Title of Invention	"DEVICE CAPABLE OF SIGNALLING THE INFLATING CONDITION IN THE TIRES"
Abstract	1. A device capable of signaling the inflating condition of a tire when screwed onto a jointing tube (5) of an Inflating value e (6) that has a self-closing valve core (7) stressed for closure by a valve spring (8), the claimed device comprising: a. an external envelope (1); b. a threaded body (4) stidabty mounted at least partially within end rotating together with the external envelope (1), which threaded body (4) Is adapted to be screwed onto the jointing tube (5); c. s plunger (11) filed with 8 rod positioned to engage the self-closing valve core (7), and housing a lamina (18) that varies geometrical configuration from a resting configuration to a pressured configuration, which variation effects movement within the rod of a bistable verve fitted with a double closing member (22); d. a movable sealing member (10) comected to the plunger (11), which movable seating member (10) delmfts, with respect to the envelope (1), at teast a first chamber (15) located under the plunger (11). and at least a second chamber (16. 20) located over the plunger (11); wherein the plunger (11) Is movably the second chamber (16, 20) with a range of motion of a magnitude sufficient to cause the opening of the self-closing valve core (7) from a closed position, said range of motion being limited between: I. a first limit stop position Into which the plunger (11) Is urged by the movable sealing member (10), and in which the plunger (11) does not cause the opening of the self-closing valve core (7), and II. a second limit stop position, in which the plunger (11) separates a third chamber (26) from the first chamber (15) by steamily contacting a gasket (25) and causes the opening of the self-closing valve core (7); wherein this second limit stop position is successively maintained only if the difference between: I. the pressure In the second chamber (16, 20), the value of which reaches the value in of the tire during the loading phase of the device, and I. the pressure in the first chamber (15), which is correctable to atmospheric pressure is maintained higher than a first pro-established threshold value, so that a resultant thrust acting on the plunger (11) is higher than the forces of the valve spring (8) and the movable sealing member (10); and e. means used for signaling the configuration of the lamina (18) or of the plunger (11), whereby the device indicates if the pressure exceeds or not sated first pre-established threshold value.

Title of Invention

"DEVICE CAPABLE OF SIGNALLING THE INFLATING CONDITION IN THE TIRES"

Abstract

1. A device capable of signaling the inflating condition of a tire when screwed onto a jointing tube (5) of an Inflating value e (6) that has a self-closing valve core (7) stressed for closure by a valve spring (8), the claimed device comprising: a. an external envelope (1); b. a threaded body (4) stidabty mounted at least partially within end rotating together with the external envelope (1), which threaded body (4) Is adapted to be screwed onto the jointing tube (5); c. s plunger (11) filed with 8 rod positioned to engage the self-closing valve core (7), and housing a lamina (18) that varies geometrical configuration from a resting configuration to a pressured configuration, which variation effects movement within the rod of a bistable verve fitted with a double closing member (22); d. a movable sealing member (10) comected to the plunger (11), which movable seating member (10) delmfts, with respect to the envelope (1), at teast a first chamber (15) located under the plunger (11). and at least a second chamber (16. 20) located over the plunger (11); wherein the plunger (11) Is movably the second chamber (16, 20) with a range of motion of a magnitude sufficient to cause the opening of the self-closing valve core (7) from a closed position, said range of motion being limited between: I. a first limit stop position Into which the plunger (11) Is urged by the movable sealing member (10), and in which the plunger (11) does not cause the opening of the self-closing valve core (7), and II. a second limit stop position, in which the plunger (11) separates a third chamber (26) from the first chamber (15) by steamily contacting a gasket (25) and causes the opening of the self-closing valve core (7); wherein this second limit stop position is successively maintained only if the difference between: I. the pressure In the second chamber (16, 20), the value of which reaches the value in of the tire during the loading phase of the device, and I. the pressure in the first chamber (15), which is correctable to atmospheric pressure is maintained higher than a first pro-established threshold value, so that a resultant thrust acting on the plunger (11) is higher than the forces of the valve spring (8) and the movable sealing member (10); and e. means used for signaling the configuration of the lamina (18) or of the plunger (11), whereby the device indicates if the pressure exceeds or not sated first pre-established threshold value.

Full Text	BACKGROUND OF THE INVENTION The present invention relates to a device capable of signalling the inflating condition in the tires; the device comprises an external covering capable of rotating together with a threaded body used for screwing the device on the body of a standard inflating valve, a chamber defined inside the threaded body, an element sensible to the pressure existing in the chamber, a member which can be deformed by the pressure considering the temperature and a system capable of signalling the position of the deformable member. STAND OF THE TECHNIQUE US-A- 5.694,969 relates to a device for inflating a tire of a wheel- A pressure relief tire valve for inflating a tire wheel assembly has a tire inflation valve body having a chamber therein with openings through the top and bottom ends thereof and having a relief opening formed in the tire valve body. An inflation valve having a spring toaded central core to allow to pass inward is located in the tre vatve body adjacent the tire inflation valve body top end for inflating the tire there through. pressure valve is located in the tire valve body for releasing air from the tire when the air pressure in the tire exceeds a predetermined level. The over pressure valve has a valve seat and valve element biased against the valve element by a compression for maintaining the valve element in a closed position until the predetermined air pressure is reached in the tire and to allow the valve element to open to release air through the valve body relief opening when the air pressure in the tire and to allow the valve element to open to release air through the valve body relief opening when the air 3 pressure in the tire exceeds the predetermined pressure. A heat variable bellows supports the compression spring and is responsive to changes in temperature of the air in the tire so that the over pressure valve can prevent over inflating the tire as well as loss of tire pressure upon an increase of air pressure in the tire from an increase in temperature of the air in the tire. This and other documents of prior art do not regard a device for signalling the inflating state in the tires, but an assembly limiting pressure in the case of an excessive increase of the air tube temperature. AIMS AND FEATURES OF THE INVENTION The present invention, as claimed, solves the problem of creating a deyice capable of signalling the inflating condition in the tires. The results obtained by means of the present invention mainly consist in the fact that the function of controlling and automatically preventing the escape of air from the tire continues to be effected by the self-closing core of the inflating varve also in presence of the device, which is, therefore, used only for signalling if the tire pressure is correct or not, without introducing the risk of the tire being deflated in case the same device presents an escape. The advantages offered by the invention consist in the fact that the tire pressure is indicated considering at least one threshold value; above said thresh old value the device signals the normal inflating state of the tire, while the same device signals the non correct inflating state when the tire pressure is below the same threshold value or another pre-established value lower than the previous threshold value; a temperature-sensing element allows to consider the temperature for defining the threshold values while a signalling system indicates if the tire inflating condition is correct or not. 4 Other advantages, features and aims of the invention may be more readily understood by referring to the accompanying drawings, which concern a preferred embodiment, in which; Fig.1 represents the device before its tightening on the valve; Fig.2 represents the device after its tightening; F»g.3 shows the device during the loading phase; Fig.4 represents the device after the loading phase; Ftg.5 demonstrates the behaviour of the device when the tire pressure has reached a value below a pre-established threshold; Fig,6 represents the device after the decrease of the tire pressure below the threshold value. DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION The device according to the invention consists of an external envelope 1, the upper wail 2 of which is preferably transparent; the envelope 1 rotates with a threaded body 4 which can be screwed on the threaded jointing tube 5 of the inflating valve 6; the valve 6 presents a self-closing valve core 7 stressed by a spring 8, The self-closing valve core 7 automatically prevents the escape of the air from the tire though allowing its inflating. The external envelope 1 can slide axially with respect to the threaded body 4, being maintained in a stable limit stop with respect to the same body 4 by means of a spring 9; the sealing between the envelope 1 and the threaded body 4 is secured by a toroidal gasket 3. A bellows 10 connects the threaded body 4 to a plunger 11. where three internal ducts 12, 13, 14 are bored. The bellows 10 allows the frictioniess axial 5 sliding of the plunger 11 inside the device; in addition, said bellows 10 separates two chambers 15. 20; the chamber 15 is found under the plunger 11 and inside the bellows 10, while the chamber 20 is located over the plunger 11 being connected to a chamber 16 with continuity; the chamber 16 is located outside the bellows 10. In this way, the plunger 11 can be axially moved by the differences of pressure which take place between the chamber 15 (lower) and the chamber 20 (upper). In a not shown embodiment, the function of the bellows 10, consisting in separating the two chambers 15. 20 located, respectively, under and over the plunger 11, is carried out by a sliding gasket which causes friction when the plunger 11 is moved. The upper part of the plunger 11 presents a housing 17 closed by a lamina 18 which can be deformed; a toroidal gasket 19 assures the sealing between the inner part of the housing 17 dosed by the lamina 18 and the chamber 20 which is located between the upper wall 2 and the lamina 18. the chamber 20 being directly connected to the chamber 16. A channel 21 joints the housing 17 with the duct 13 bored inside the rod of the plunger 11; the rod presents two portions with different external diameters. The lamina 18 controls the channel 21 by means of a bistable valve 22 fitted with a double closing de vice, the valve 22 being operated by the same lamina 18 presenting a first position of stability when a first section of the closing device closes the connection between the housing 17 and the channel 21 allowing the connection between the duct 13 and the channel 21, and a second position of stability when a second section of the closing device closes the connection between the duct 13 and the channel 21 allowing the connection between the housing 17 and the channel 21. The duct 14 connects the internal part of the housing 17 to the chamber 15 located under the plunger 11 and inside the bellows 10, the duct 14 being con trolled by a self-dosing valve 23 allowing the air passage from the housing 17 into the chamber 15, but not vice versa. 6 The duct 12 connects the chambers 16 (located in the external part of the bellows 10) and 20 (situated over the plunger 11) to the channel 21 where the rod 24 of the bistable valve 22 with the double dosing device is inserted. The envelope 1 transmits a torque to the threaded body 4, i.e. a rotation: in practice, when the device is screwed on the valve 6; the valve 6 is screwed on the envelope 1 with the fingers in order to transmit the torque which causes the rotation of the threaded body 4 for clamping the gasket 25 used for sealing the body of the valve 6 with respect to the device. A chamber 26 is defined inside the jointing tube 5 of the inflating valve 6, the chamber 26 being separated from the chamber 15 only if the plunger 11 is found in the bottom limit stop so that the section of its rod having the larger diameter clamps the internal edge of the gasket 25. When the gasket 25 is completely damped, the chamber 15 located inside the bellows 10 is connected to the atmosphere 27 through a duct 28, a groove 31 and a channel 29. The duct 28 is controlled by a self closing valve 30. which is in opening position for allowing the air flow from the chamber 15 to the channel 21 and.the channel 29, and consequently to the atmosphere 27; only if the gasket 25 has been completely clamped; in the case of insufficient clamping of the gasket 25 the valve 30 is not open, therefore, the passage of the air from the chamber 15 to the channel 21 and the channel 29, and consequently to the atmosphere 27, is prevented; this occurs even in the case of incomplete damping of the gasket 25, provided that the gasket 25 is brought into contact with the threaded jointing tube 5. The device shown in Fig.1 has not yet been damped on the valve 5. 6; in this case the attempt of loading the device causes no effect, therefore, the device automatically unloads, since, on one hand, the chamber 26, the ducts 13, 21, 12. the chamber 16 and the chamber 20, located over the plunger 11. do not maintain the tire pressure because of the air escape which takes place be- 7 tween the gasket 25, insufficiently clamped, and the valve body 5, with consequent blow-by and direct discharging to the atmosphere 27 through the channel 29, and, on the other hand, the discharge to the atmosphere of the chamber 15 located under the plunger 11 cannot occur (during the transient loading, the chamber 15 is subject to the air tube pressure before being isolated from the chamber 28 at the instant when the portion of the rod of the plunger 11 having the external larger diameter clamps the internal edge of the gasfcet 25): in fact, the vaive 30 remains dosed since it opens only because of the clamping compression of the gasket 25 and because of the thrust applied on the same vaive 30 by the pressure existing in the chamber 15, In addition, if the clamping of thegasket 25 on the threaded jointing tube 5 is incomplete, so that the blow-by towards the channel 29 and groove 31 occurs, the air will also tend to flow back to the chamber 15 through the groove 31 be cause of the losses of pressure due to the back flow through the channel 29, The right equilibrium between the losses of pressure in said channels 28, 29 can assure the unloading of the device for insufficient damping of the gasket 25, even in the case of absence of the self-closing valve 30. For this reason, it is possible to immediately understand that the device is insufficiently tight, anyhow, situations of risk of deflating of the tire for insufficient tightening do not occur, Rg.2 showsvthe device after its tightening; after the complete screwing of the device on the valve 5,6 of the tire, and therefore, obtaining the adequate tightening of the gasket 25 through screwing of the body 4 on the valve 5, 6, the device is ready to work. In the condition of Fig.2 the device exactly works as a cap of a traditional tire inflating valve, i.e. the device does not carry out any function, but it is only used for protecting the valve. The tire valve 5, 6 is closed by the self-closing valve core 7, therefore, the air tube is neither connected to the chamber 26, nor to the atmosphere. Usually, the lamina 18 is bent upwards; this bending is maintained untiJ the pressure in the chamber 20 has reached a sufficiently high value with respect to the value of the pressure existing in the housing 17. (i.e. the atmospheric pressure, since the housing 17 is connected to the atmosphere, as it will more readily understood by referring to following description), therefore, when the pressure value is sufficiently high, the bending is directed downwards. In fact, the bending of the lamina 18 depends on the difference between the pressure in the chamber 20, which successively will be connected to the tire air tube, and the pressure in the housing 17, which will be connected to the atmosphere. If this difference of pressure, which advantageously can be corrected considering the temperature value in the case of balanced measure effected by a bimetal 18, is sufficiently high, the bimetal 18 will bend down wards, for reaching a stable downward bent position shown in Figs 3, 4 representing .the functioning .of the device, otherwise the bimetal 18 will maintain its upward bent configuration. The subsequent operation consists in loading the device; this operation.takes place (Fig.3) by means of a manual external axial thrust P which causes the axial motion of the external envelope 1 with respect to the threaded body 4 by exceeding the thrust of the spring 9. Because of the thrust Papplied on the external body of the device (external envelope 1, wail 2) aiso the plunger 11 is moved downwards by the thrust P transmitted to the lamina 18 through the upper wall 2; owing to the thrust P, the lamina 18 is bent downwards just as it would happen if the pressure in the chamber 20 was sufficiently higher than the pressure in the housing 17. This is the loading operation, when the device is set at work, which would happen if the difference between the pressure in the chamber 20, on one hand, and the pressure in the housing 17 and the chamber 15 on the other hand, was sufficiently high. It is remarkable that in this first phase of the transient loading, the difference between the pressure in the chamber 20, on one hand, and the 9 pressure in the chamber 15 and the housing 17 (connected to each other through the duct 14) on the other hand, has not yet happened and stabilised, therefore, the bending of the lamina 18 and the downward motion of the plunger 11 occur only because-of the mechanical thrust P. This new geometrical configuration of me lamina 18 also causes the motion of the valve 22 fitted with a double closing device towards the first position of stability; therefore, the vaive 22 connects the duct 13 to the duct 12 and the chambers 16, 20, and disconnects the jointing between the channel 21 and the housing 17. It is to remembeLthat the chamber 20 extends from the upper surface of the lamina 18 to the chamber 16 external to the bellows 10 with continuity. In addition, owing to the same thrust P the plunger 11 is moved downwards; therefore, the lower end of the rod of the plunger (inside which the duct 13 is bored) pushes downwards the end of the self-closing valve core 7, which opens to allow the air inside the tube to fill the chamber 26 defined inside the jointing tube 5 of the inflating valve 6. The gasket 25 is also capable of sealing the rod of the plunger 11 by means of its internal lip only when the plunger 11, the rod of which presents two diameters, is moved towards the low limit stop shown in Fig.3 (loading position). Consequently, if at the beginning of the opening of the self-closing valve core 7, during the downward motion of the plunger 11, the air coming out of the tube fills the chamber 26, the chamber 15, the duct 28, the channel 29, the qroove 31 (and the ducts 12,13, the channel 21, and the chambers 16, 20, since those cavities are connected to each other), in the moment when the plunger 11 has reached its low limit stop, and, therefore, the sealing between the rod of the plunger 11 and the gasket 25 is allowed, also the separation of the chamber 26 defined inside the jointing tube 5 of the inflating valve 6 takes place from the chamber 15 located under the plunger 11 and inside the bellows 10. It is remarkable that the sealing on the rod of the plunger 11, which is necessary for insulating the chambers 26 and 15 when the plunger 11 is found at the low limit stop, can also be obtained by means of a gasket different from the gasket 25. for example, a toroidal gasket integral with the threaded body 4: the solution consisting in integrating the sealing in the same gasket 25 allows the reduction of the axial dimensions. Once this condition is reached, the pressure existing in the air tube is established in the chamber 26, the ducts 12, 13, and the chambers 16 and 20; vice versa, the atmospheric pressure is established in the chamber 15 and the housing 17 and in the ducts 14. 28, 29 and the groove 31. Two cavities have, therefore, been separated, the first cavity 20 is found over the plunger 11, while the second cavity 15 is located under the plunger 11; this separation is due to the gasket 25 on one hand (sealing on the rod of the plunger 11) and, on the other hand, the bellows 10 (sealing on the plunger 11). When the external thrust P is removed, if the difference between the pressure in the chamber 20 and the pressure in the housing 17 (i.e. between the tube and the atmosphere) is sufficiently high (we remember that the chamber 15, through the internal duct 14, is also connected to the housing 17, which, in this way. is subject to the atmospheric pressure), the lamina 18 will maintain the down ward bent configuration due to the thrust P, even when the same thrust P has been removed, and consequently the connection of the duct 13 to the housing 17 through the channel 21 will be dosed, but the connection of the duct 13 to the duct 12 (and, therefore, of the duct 13 to the chambers 16, 20) through the same channel 21 will be open, thanks to the first position of stability reached by the bistable valve 22 fitted with a double dosing device. After the releasing of the thrust P, the spring 9 and the air pressure in the chambers 16, 20 move the external envelope 1 back upwards which reaches its original position shown in Fig.4. In this configuration, if the air pressure (air tube pressure) existing in the chamber 20 (eventually corrected considering the temperature value in the case of a balanced measure effected by a bimetal 18), is such as to exert a stress on the upper surface of the lamina 18, the stress WO 99/61264 11 being sufficient to maintain the lamina 18 bent downwards (in fact, the atmospheric pressure exists in the housing 17); said stress also holds the plunger 11 fastened in its low limit stop, since, owing to difference in the active sections, said stress easily exceeds the thrust due to the air tube pressure on the rod of the plunger 11 and the thrust of the spring 8. In such a way, the rod of the plunger 11 maintains the self-closing valve core 7 open for assuring the continuous connection between the air tube and the measuring system 18 through both the chamber 26 and the chamber 20, where the air tube pressure exists. Each air escape is obviously prevented by the sealing due to the gaskets 25. 19, 3 and the beliows 10. Consequently, as shown in Fig.4, as long as the tire pressure (eventually corrected considering the temperature value) is maintained at a sufficient value, i.e. above the established threshold value defining the low limit of the correct inflating pressure of the tire, the device will remain loaded, i.e. with the lamina 18 bent down wards and the plunger 11 in its low limit stop; the same device will maintain the connection to the air tube.through the self-dosing valve core 7 It is necessary to specify that the utility of the function attained by the device (i.e. signalling when the tire pressure falls bellow at least one pre-established threshold value) is relative to all normal working conditions, where the deflating of the tire takes place slowly, therefore, in a way difficult to perceive by means of common observation (phenomenon which takes place either be cause of natural causes, (ike an escape through the structure of the same tire, or because of external causes, like small punctures which cause a slow deflating); therefore, the device allows the duration needed for sensing the signal and operating as soon as possible in order to restore the most correct pressure value (and/or repair the eventual puncture for preventing the compulsory stop of the vehicle). Obviously, the device will not offer any practical utility in the case of punctures or other serious phenomena causing the deflating of the tire in such a quick way that the duration for sensing the signal and acting consequently is insufficient. Naturally, the pre-established threshold value defining the low limit of the.cor-rect inflating pressure can be defined in such a way to assure that the signalling of the exceeding of the same threshold value occurs when the pressure value in the tire is still sufficiently high to allow the duration needed for sensing the signal and acting in the usual operating situations when the deflating takes place slowly. When the pressure (eventually corrected considering the temperature value) falis below said pre-established threshold value (or beiow another threshold value lower than the previous), as shown in Fig.5, the lamina 18 will bend up wards. This bending will immediately enable the bistable valve 22 fitted with a double closing device to automatically commute from the first to the second position of stability for closing the connection between the duct 13 and the chambers 16 and 20 (through the channel 21 and the duct 12); vice versa the connection between the chamber 20 and the housing 17 (through the duct 12 and the channel 21) remains open. The housing 17, through the duct 14, is connected to the chamber 15 which, in its turn, is connected to the atmosphere 27 through the duct 28, the channel 29 and the groove 31. The aim to be attained when this situation occurs is the safe dosing of me tire, therefore, the tire is insulated from the environment by means of the self-closing valve core 7 for preventing any air escape through the valve core 7 or the device. For this purpose, the device is so planned that the downward thrust acting on the group of the plunger 11 because of the difference between the pressure in the upper chamber 20 (where the tube pressure exists) and the pressure in the lower chamber 15 (where the environmental pressure exists), when the difference in pressure between the chamber 20 and the housing 17 is capable of maintaining the lamina 18 bent downwards, is so high to widely exceed the upward thrust acting on the plunger 11; this thrust being caused by the valve core 7 stressed upwards by the spring 8, the air tube pressure acting on the rod WO 99/61264 13 section of the plunger 11 and the elasticity of the bellows 10. In this way, the plunger 11 is guaranteed to remain in the loading position (low limit stop) even in presence of external perturbations (vibrations, forces of inertia, etceteras). The starting of the phenomenon which causes the unloading of the device is due to a change in the tire pressure (eventually corrected considering the temperature vaiue) referred to the atmospheric pressure, said change being capable of bending the lamina 18 upwards, when the pressure in the cavities 17. 14. 15, 28 and 29 still presents the atmospheric value and the pressure in the cavities 16, 20, 12, 21, 13 and 26 presents the air tube value (which has just fallen below the established threshold). In these conditions, the difference between the pressure in the upper chamber 20 (where the tube pressure exists) and the pressure in the lower chamber 15 (where the environmental pressure exists) acting on the plunger 11 is anyway still capable of maintaining the plunger 11 in the loading position (i.e. in the low limit stop): in fact, the planning of the active sections of the plunger 11 and of the relative rod will be chosen in such way that the resultant vector of the various above listed forces acting on the plunger 11 will anyway be directed downwards also for tire pressure values lower than the pre-established threshold value, while, once above said threshold value, the lamina 18 will bend upwards. Since the de vice has been planned for a practical utility in all normal working conditions where the deflating of the tire takes place slowly, at the instant when the tire pressure (eventually corrected considering the temperature) passes to a value lower than the threshold pre-established for this purpose, the lamina 18 will bend immediately upwards, but the resultant of the forces acting on the plunger 11 (the module of which will be changed in its turn, but only by a very small quantity the phenomenon being slow) will keep always directed down wards; furthermore, said resultant will present a value such as to permanently maintain the plunger 11 in the low limit stop, until the pressure in the upper chamber 20 falls considerably. This notable fall occurs as a direct immediate consequence of the upward bending of the lamina 18. WO 99/61264 14 In fact, the motion towards the second position of stability of the valve 22 fitted with a double dosing device consequent to the modification of the geometrical configuration of the famrna 18 causes a sudden change in the pressures within the various cavities. The jointing between the duct 13 (which remains at the tire pressure together with the chamber 26) and the chambers 16 and 20 (thorough the ducts 21 and 12) is disconnected, while the chambers 20 and 16 are emptied through the same duds 12 and 21, the housing 17 (which now is connected to the channels 21 and 12), the duct 14,.the chamber 15 and the channel 28, the groove 31 and the channel 29 which are directly connected to the atmosphere 27. In this way, the pressure in the chamber 20 quickly fails, while, because of the losses of pressure wnich hinder the air flow to the atmosphere 27 through the duct 28, the groove 31 and the channel 29, the pressure in the chamber 15 tends to increase (previously the pressure in the chamber 15 presented the atmospheric value). This phenomenon associated with the upward thrust acted on the rod of the plunger 11 by the self-closing valve core 7 stressed by the spring 8 and the bellows 10, causes the sudden upstroke of the plunger 11 towards its tow limit stop. As soon as the upstroke of the plunger 11 starts, the rod with two diameters disengages from the gasket 25: in this way a direct connection is suddenly created between the chamber 26, which until the self-closing vatve core 7 doses, remains at the tire pressure and is potentially fed by an considerable air flow, and the chamber 15 located under the plunger 11. In this way, the pressure in the chamber 15 immediately reaches the tire pressure value by exerting an upward stress on the plunger 11; said pressure value is maintained until the self-closing vatve core 7 completely closed by reaching the scope of the present invention, while the self-closing valve 23 prevents the air from flowing towards the housing 17, and from this one, through the ducts 21 and 12, the air can reach the chamber 20 situated over the plunger 11, where in the meantime WO 99/61264 15 the pressure has fallen with respect to the tire value presented before exceeding the threshold. In this way, the plunger 11, until the self-dosing valve core 7 is completely closed, will be subject to an upward resultant thrust, the resultant thrust being due to the difference between the pressure in the chambers 15 and 20 plus the thrust applied to the needle of the self-dosing valve core 7 stressed by the spring 8 and the thrust of the beltows 10, the resultant thrust being sufficient to move the plunger 11 upwards, even if an identical pressure value should be found in the chambers 15 and 20. In fact, the pressure in the chamber 15 re mains at the tire value, since the outlet flow from the self-closing valve core 7 still open is much higher than the loss flowing towards the atmosphere through the duct 28, the groove 31 and the channel 29: this fact assures that, even if the pressure in the chamber 20 should fall by a small quantity, or, even, revert to the value of the air tube at the moment when the disengagement of the rod of the plunger 11 from the gasket 25 occurs, as it might occur if the self-closing valve 23 was removed, the resultant of the stresses acting on the plunger 11 would anyway be always directed upwards thanks to the elastic action of the spring 8 and the bellows 10. This fact causes the sudden upstroke of the plunger towards its high limit stop and the closing of the self-closing valve core 7 by obtaining the desired result and the unloading of the device: when the self-dosing valve core 7 closes, both chambers 20 and 15 are suddenly connected to environmental pressure (atmospheric pressure), while the plunger 11 completes its upstroke until it reaches the high limit stop thanks to the elasticity of the bellows 10 (Fig.6). In this way, the tire is immediately insulated from the environment; therefore, the self-closing valve core 7 always performs its function of safety and closing against air escapes through the inflating valve. This fact prevents any risk due to eventual escapes in the device. If the plunger 11, after the loading phase, remains in the position such as to keep the self-closing valve core 7 open, i.e. in its low limit stop, that means the WO 99/61264 16 pressure in the air tube (eventually corrected considering the temperature value) is higher than the pre-established threshold value defining the low limit of the correct inflating tire pressure; vice versa, when the plunger 11 moves back to the high limit stop {i.e. it unloads) the pressure in the air tube (eventually corrected considering the temperature value) is lower than said pre-estab-iished threshold value, or another pre-defined threshold value lower than the previous one. ft is, then, sufficient to sense either the bendina of the lamina 18 or the position of the plunger 11 (the stroke of which is of some mm.) for signalling the exceeding or not of the threshold value to the external with known means, the threshold value defining the low limit of the correct tire pressure. For example, a chromatic variation in function of the position of the plunger 11 can be displayed on a transparent visor applied to the wall 2. In addition, the displacement of the plunger 11 (or the change in the geometrical configuration of the lamina 18) can set at work an electrical circuit by means of which the emission of optical andfor acoustic signals can be obtained, said signals being transmitted by induction, or hertzian waves etc. with all its possible combinations. The device can obviously be reloaded indefinite times; all times the condition of exceeding the threshold value will occur it will automatically unload and remain unloaded until subsequent hand loading by assuring that the signal can be received. Fig.6 shows the device after the falling in the tire pressure; in this case, the components of the device are again in the position of Fig.2. 17 CIaim 1. A device capable of signalling the inflating condition of a tire when screwed onto a jointing tube (5) of an Inflating value (6) that has a self-closing vatve core (7) stressed for closure by a valve spring (8), the claimed device comprising: a. an external envelope (1); b. a threaded body (4) shdabty mounted at least partially within end rotating together with the external envelope (1), which threaded body (4) Is adapted to be screwed onto the jointing tube (5); c. a plunger (11) filed with a rod positioned to engage the self-closing valve core (7), and housing a lamina (18) that varies geometrical configuration from a resting configuration to a pressured configuration, which variation effects movement within the rod of a bistable very fitted with a double closing member (22); d. a movable sealing member (10) connected to the plunger (11), which movable sealing member (10) delmfts, with respect to the envelope (1), at least a first chamber (15) located under the plunger (11). and at least a second chamber (16. 20) located over the plunger (11); wherein the plunger (11) Is movabty the second chamber (16, 20) wlh a range of motion of a magnitude sufficient to cause the opening of the self-closing valve core (7) from a closed position, said range of motion being limited between: I. a first limit stop position Into which the plunger (11) Is urged by the movable sealing member (10), and in which the plunger (11) does not cause the opening of the self-closing vatve core (7), and II. a second limit stop position, in which the plunger (11) separates a third chamber (26) from the first chamber (15) by sealmgly contacting a gasket (25) and causes the opening of the self-closing vatve core (7); wherein this second limt stop position is successively maintained only If the difference between: I. the pressure In the second chamber (16, 20), the value of which reaches the value in of the tire during the loading phase of the device, and 18 I. the pressure in the first chamber (15), which is connect able to atmospheric pressure Is maintained higher than a first pre-established threshold value, so that a resultent thrust acting on the plunger (11) is higher than the forces of the valve spring (8) and the movable sealing member (10); and e. means used for signalling the configuration of the lamina (18) or the position of the plunger (11), whereby the device Indicates If the pressure In the tire exceeds or not said first pre-established threshold value. 2.Device as in claim 1, wherein the lamina (18) with variable geometrical configuration acts on the double closing member (22) consisting of a bistable valve (22), the lamina (18) presenting a first position of stability and a second position of stabifty; in which first posiion of stability, the bistable valve (22) connects a first duct (12, 21) to a plunger housing (17) and closes the connection between the first duct (12) and a second duct (13); and in which second position of stability, the bistable vatve (22) connects the second dud (13) to the first duct (21, 12) and closes the connection between a the first duct (12, 21) and the housing (17). 3. Device as In claim 2, wherein the lamina (18) with variable geometrical configuration is a bimetal for which the pressure threshold, at which the commutation of the geometrical configuration occurs, is a function of the temperature. 4.Device as in claim 1, wherein the movable sealing member (10) comprises a beiows (10) allowing the frldloniess axial translation of the plunger (11) inside the device, and separates a first chamber (15) from a second chamber (16, 20), said first chamber (15) and second chamber (16, 20) being respectively located under and over the plunger (11). 5. Device as in claim 1, wherein en external axial force (P) applied to the external envelope (1): a. causes the axial translation of the external housing of the device and moves the envelope (1) with respect to the threaded body (4) against fi thrust of a spring (9), so that the envelope (1) passes 10 n. from the frst limit stop position which Is in absence of said force maintained by the thrust of the spring (9), Hi. to a second timl stop position, in which the envelope (1) remains only until the external force (P) is released; b. is transmitted from the well (2) to the lemine (18), and c. causes both: tv, the change or the geometrical configuration of the lamina (18) toward? n$ second configuration of stability and, v. the motion of the plunger (11) towards the second limit stop position, h which the plunger (11) causes the opening of the sef-ctoslng valve core (7), and by interfering win the gasket (25), separates the third chamber (26) from the frst chamber (15). 6. Device as in claim 1, wherein after the releasing of the force (P), the spring (9) and the thrust of the air pressure in the second chamber (16, 20) move the external envelope (1) towards the first stable limit stop position. 7. Device as in claim 1, wherein the position of the plunger (11) signals the exceeding or not of at least a first pre-established threshold pressure value, and wheren the wall (2) is transparent for displaying an indication consisting of a chromatic change as a function of the position of the plunger (11). and the configuration of the lamina (18). 8. Device as in claim 7, wheren the displacement of the plunger (11) and the change In the geometrical configuration of the lamina (18) set at work an electrical circuit causing the emission of optical and/or acoustic signals. 9. Device as in claim 2, wherein the lamina (18) with variable geometrical configuration Is connected to a housing (17) by a sealing member (19); and wherein further the bistable valve (22), through a channel (21), alternative* connects a first duct (12) to a second duct (13), or to the housing (17) according to the configuration of stabllly reached by the lamina (18). such that when the device is unloaded, the lamina (18) maintains a first configuration in which the plunger (11) does not cause the opening of the setf-closing vaive core (7), and the chambers (15. 16. 20. 17. 26). the ducts $ 20 and the channels (12,13, 21) communicate with the atmosphere (27). 10. Device as In claim 1 (2), wherein the force necessary to move the plunger (11) from the first to the second limit stop position is transmitted by said envelope (1) and wall (2) to plunger (11) through the wal (2), which directly acts on the lamina (18 and causes the deformation of the lamina (18) to the second configuration; In this configuration the plunger (11) is located at the second limit stop position, the bistable value fitted with a double closing member (22) connects the second duct (13) to the first duct (12), so that pressure of the tire exists in the third chamber (26), the second duct (13), the first duct (12) and the second chamber (16, 20), while the atmospheric pressure exists n the housing (17), a third duct (14) and the first chamber (15); in which position said second configuration of lamina (18) is maintained onty If the difference between the pressure In the second chamber (16, 20) and in the housiig (17) exceeds at least a first pre-established threshold value; In said condition the deference between the pressure In second chamber (16, 20) and first chamber (15) Is the same as the difference between the pressure in second chamber (16, 20) and housing (17); until said difference in pressure is sufficient to maintain the second configuration of the lamina (18) the resultant force on the plunger (11) is sufficient to assure that the plunger (11) is maintained in the second limit stop poslion, so that the device remains loaded; if said deference In pressure Is, or soon after decreases, until a value lower than a second and tower pre-established threshold value, the lamina (18) Instantaneously moves again towards the first configuration; in such a way, the bistable valve fitted with a double dosing member (22) intercepts the communication between the first duct (12) and the second duct (13) and connects the first duct (12) to the housing (17) which, in Is turn, through third duct (14), the first chamber (15) and the channels (28, 29), is connected to the atmosphere (27); this causes the quick felling of the pressure In the second chamber (16, 20) to the atmospheric value; for this reason the plunger (11) moves again towards the frsf stabie limit stop poslion; therefore, the lamina (18) indicates if the 7 21 pressure in the tre exceeds or not at least a higher pre-established threshold value and causes the recovery of the plunger (11) to the first limit stop position (unloading condition) In which the plunger (11) does not cause the opening of the self-dosing vatve core (7) which closes again the communication with the Internal part of the tire. 11. Device as In claim 9, wherein the force necessary to move the plunger (11) from the first to the second Iimit stop position during the loading phase Is applied to the envelope (1) and the wad (2) Integral with the envelope (1), said force is transmitted by said envelope (1) and waft (2) to plunger (11) through the wall (2), which directly acts on the lamina (18) with variable geometrical configuration and causes the deformation of the lamina (18) to a second configuration; in this configuration the plunger (11) is located at the second llmft stop position, the bistable double closing member (22) connects the second dud (13) to the first duct (12), so that pressure of the tire exists In second chamber (26), second duct (13), first duct (12) and second chamber (16, 20). while the atmospheric pressure exists In the housing (17). a third duct (14) and in first chamber (15); said second configuration of the lamina (18) can be maintained only f the difference between the pressure In second chamber (16, 20) and housing (17) exceeds at least a first pre-established threshold value; In said condition the difference between the pressure In second chamber (16, 20) and first chamber (15) Is the same as the difference between the pressure in second chamber (18.20) and housing (17); until said difference in pressure Is sufficient to maintain the second configuration of the lamina (18) the resultant on the plunger (11) Is sufficient to assure that the plunger (11) is maintained In the second limit stop position, so that the device remains loaded; If said difference In pressure Is. or soon after decreases, untl a vatue tower than a second and tower pre-established threshold value, the lamina (18) instantaneously moves again towards the first configuration; In such a way, the bistable vatve fitted with a double closing member (22) intercepts the communication between the first duct (12) and the second duct (13) and connects the first duct (12) to the housing 8 22 (17), which, in its turn, through the third duct (14), the first chamber (15) and the channels (28, 29), Is connected to the atmosphere (27); this causes the quick falling of the pressure in the second chamber (16, 20) to the atmospheric value, for this reason the plunger (11) moves again towards the first limit stop position; therefore, the lamina (18) Indicates If the pressure in the tire exceeds or not at feast a higher pre-established threshold value and causes the recovery of the plunger (11) to the first limit stop position (unloading condition) in which the plunger (11) does not cause the opening of the setf-closing valve core (7) which closes again the communication with the internal part of the tire. 12. Device as in claim 9, wherein the lamina (18) with variable geometrical configuration is a bimetal (18) allowing to change the pressure threshold which causes the commutation of the configuration tn function of the temperature. 13. Device as In daft 5, wherein after the releasing of the force (P). the spring (9) and the thrust of the air pressure existing in the second chamber (16, 20) move again the external envelope (1) towards the first stable limit stop position. 14. Device as in claim 1, wherein the displacement of the plunger (11) or the change in geometrical configuration of the lamina (18) set at work an electrical circuit by means of which the emission of optical and/or acoustic signals is obtained to be transmitted via electromagnetic waves. 1. A device capable of signaling the inflating condition of a tire when screwed onto a jointing tube (5) of an Inflating value e (6) that has a self-closing valve core (7) stressed for closure by a valve spring (8), the claimed device comprising: a. an external envelope (1); b. a threaded body (4) stidabty mounted at least partially within end rotating together with the external envelope (1), which threaded body (4) Is adapted to be screwed onto the jointing tube (5); c. s plunger (11) filed with 8 rod positioned to engage the self-closing valve core (7), and housing a lamina (18) that varies geometrical configuration from a resting configuration to a pressured configuration, which variation effects movement within the rod of a bistable verve fitted with a double closing member (22); d. a movable sealing member (10) comected to the plunger (11), which movable seating member (10) delmfts, with respect to the envelope (1), at teast a first chamber (15) located under the plunger (11). and at least a second chamber (16. 20) located over the plunger (11); wherein the plunger (11) Is movably the second chamber (16, 20) with a range of motion of a magnitude sufficient to cause the opening of the self-closing valve core (7) from a closed position, said range of motion being limited between: I. a first limit stop position Into which the plunger (11) Is urged by the movable sealing member (10), and in which the plunger (11) does not cause the opening of the self-closing valve core (7), and II. a second limit stop position, in which the plunger (11) separates a third chamber (26) from the first chamber (15) by steamily contacting a gasket (25) and causes the opening of the self-closing valve core (7); wherein this second limit stop position is successively maintained only if the difference between: I. the pressure In the second chamber (16, 20), the value of which reaches the value in of the tire during the loading phase of the device, and I. the pressure in the first chamber (15), which is correctable to atmospheric pressure is maintained higher than a first pro-established threshold value, so that a resultant thrust acting on the plunger (11) is higher than the forces of the valve spring (8) and the movable sealing member (10); and e. means used for signaling the configuration of the lamina (18) or of the plunger (11), whereby the device indicates if the pressure exceeds or not sated first pre-established threshold value.

Full Text

BACKGROUND OF THE INVENTION
The present invention relates to a device capable of signalling the inflating condition in the tires; the device comprises an external covering capable of rotating together with a threaded body used for screwing the device on the body of a standard inflating valve, a chamber defined inside the threaded body, an element sensible to the pressure existing in the chamber, a member which can be deformed by the pressure considering the temperature and a system capable of signalling the position of the deformable member.
STAND OF THE TECHNIQUE
US-A- 5.694,969 relates to a device for inflating a tire of a wheel- A pressure relief tire valve for inflating a tire wheel assembly has a tire inflation valve body having a chamber therein with openings through the top and bottom ends thereof and having a relief opening formed in the tire valve body. An inflation valve having a spring toaded central core to allow to pass inward is located in the tre vatve body adjacent the tire inflation valve body top end for inflating the tire there through. pressure valve is located in the tire valve body for releasing air from the tire when the air pressure in the tire exceeds a predetermined level. The over pressure valve has a valve seat and valve element biased against the valve element by a compression for maintaining the valve element in a closed position until the predetermined air pressure is reached in the tire and to allow the valve element to open to release air through the valve body relief opening when the air pressure in the tire and to allow the valve element to open to release air through the valve body relief opening when the air

3
pressure in the tire exceeds the predetermined pressure. A heat variable bellows supports the compression spring and is responsive to changes in temperature of the air in the tire so that the over pressure valve can prevent over inflating the tire as well as loss of tire pressure upon an increase of air pressure in the tire from an increase in temperature of the air in the tire.
This and other documents of prior art do not regard a device for signalling the inflating state in the tires, but an assembly limiting pressure in the case of an excessive increase of the air tube temperature.
AIMS AND FEATURES OF THE INVENTION
The present invention, as claimed, solves the problem of creating a deyice capable of signalling the inflating condition in the tires. The results obtained by means of the present invention mainly consist in the fact that the function of controlling and automatically preventing the escape of air from the tire continues to be effected by the self-closing core of the inflating varve also in presence of the device, which is, therefore, used only for signalling if the tire pressure is correct or not, without introducing the risk of the tire being deflated in case the same device presents an escape.
The advantages offered by the invention consist in the fact that the tire pressure is indicated considering at least one threshold value; above said thresh old value the device signals the normal inflating state of the tire, while the same device signals the non correct inflating state when the tire pressure is below the same threshold value or another pre-established value lower than the previous threshold value; a temperature-sensing element allows to consider the temperature for defining the threshold values while a signalling system indicates if the tire inflating condition is correct or not.

4
Other advantages, features and aims of the invention may be more readily understood by referring to the accompanying drawings, which concern a preferred embodiment, in which;
Fig.1 represents the device before its tightening on the valve; Fig.2 represents the device after its tightening; F»g.3 shows the device during the loading phase; Fig.4 represents the device after the loading phase; Ftg.5 demonstrates the behaviour of the device when the tire pressure has reached a value below a pre-established threshold; Fig,6 represents the device after the decrease of the tire pressure below the threshold value.
DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
The device according to the invention consists of an external envelope 1, the upper wail 2 of which is preferably transparent; the envelope 1 rotates with a threaded body 4 which can be screwed on the threaded jointing tube 5 of the inflating valve 6; the valve 6 presents a self-closing valve core 7 stressed by a spring 8, The self-closing valve core 7 automatically prevents the escape of the air from the tire though allowing its inflating.
The external envelope 1 can slide axially with respect to the threaded body 4, being maintained in a stable limit stop with respect to the same body 4 by means of a spring 9; the sealing between the envelope 1 and the threaded body 4 is secured by a toroidal gasket 3.
A bellows 10 connects the threaded body 4 to a plunger 11. where three internal ducts 12, 13, 14 are bored. The bellows 10 allows the frictioniess axial

5
sliding of the plunger 11 inside the device; in addition, said bellows 10 separates two chambers 15. 20; the chamber 15 is found under the plunger 11 and inside the bellows 10, while the chamber 20 is located over the plunger 11 being connected to a chamber 16 with continuity; the chamber 16 is located outside the bellows 10. In this way, the plunger 11 can be axially moved by the differences of pressure which take place between the chamber 15 (lower) and the chamber 20 (upper).
In a not shown embodiment, the function of the bellows 10, consisting in separating the two chambers 15. 20 located, respectively, under and over the plunger 11, is carried out by a sliding gasket which causes friction when the plunger 11 is moved.
The upper part of the plunger 11 presents a housing 17 closed by a lamina 18 which can be deformed; a toroidal gasket 19 assures the sealing between the inner part of the housing 17 dosed by the lamina 18 and the chamber 20 which is located between the upper wall 2 and the lamina 18. the chamber 20 being directly connected to the chamber 16. A channel 21 joints the housing 17 with the duct 13 bored inside the rod of the plunger 11; the rod presents two portions with different external diameters. The lamina 18 controls the channel 21 by means of a bistable valve 22 fitted with a double closing de vice, the valve 22 being operated by the same lamina 18 presenting a first position of stability when a first section of the closing device closes the connection between the housing 17 and the channel 21 allowing the connection between the duct 13 and the channel 21, and a second position of stability when a second section of the closing device closes the connection between the duct 13 and the channel 21 allowing the connection between the housing 17 and the channel 21. The duct 14 connects the internal part of the housing 17 to the chamber 15 located under the plunger 11 and inside the bellows 10, the duct 14 being con trolled by a self-dosing valve 23 allowing the air passage from the housing 17 into the chamber 15, but not vice versa.

6
The duct 12 connects the chambers 16 (located in the external part of the bellows 10) and 20 (situated over the plunger 11) to the channel 21 where the rod 24 of the bistable valve 22 with the double dosing device is inserted. The envelope 1 transmits a torque to the threaded body 4, i.e. a rotation: in practice, when the device is screwed on the valve 6; the valve 6 is screwed on the envelope 1 with the fingers in order to transmit the torque which causes the rotation of the threaded body 4 for clamping the gasket 25 used for sealing the body of the valve 6 with respect to the device.
A chamber 26 is defined inside the jointing tube 5 of the inflating valve 6, the chamber 26 being separated from the chamber 15 only if the plunger 11 is found in the bottom limit stop so that the section of its rod having the larger diameter clamps the internal edge of the gasket 25.
When the gasket 25 is completely damped, the chamber 15 located inside the bellows 10 is connected to the atmosphere 27 through a duct 28, a groove 31 and a channel 29. The duct 28 is controlled by a self closing valve 30. which is in opening position for allowing the air flow from the chamber 15 to the channel 21 and.the channel 29, and consequently to the atmosphere 27; only if the gasket 25 has been completely clamped; in the case of insufficient clamping of the gasket 25 the valve 30 is not open, therefore, the passage of the air from the chamber 15 to the channel 21 and the channel 29, and consequently to the atmosphere 27, is prevented; this occurs even in the case of incomplete damping of the gasket 25, provided that the gasket 25 is brought into contact with the threaded jointing tube 5.
The device shown in Fig.1 has not yet been damped on the valve 5. 6; in this case the attempt of loading the device causes no effect, therefore, the device automatically unloads, since, on one hand, the chamber 26, the ducts 13, 21, 12. the chamber 16 and the chamber 20, located over the plunger 11. do not maintain the tire pressure because of the air escape which takes place be-

7
tween the gasket 25, insufficiently clamped, and the valve body 5, with consequent blow-by and direct discharging to the atmosphere 27 through the channel 29, and, on the other hand, the discharge to the atmosphere of the chamber 15 located under the plunger 11 cannot occur (during the transient loading, the chamber 15 is subject to the air tube pressure before being isolated from the chamber 28 at the instant when the portion of the rod of the plunger 11 having the external larger diameter clamps the internal edge of the gasfcet 25): in fact, the vaive 30 remains dosed since it opens only because of the clamping compression of the gasket 25 and because of the thrust applied on the same vaive 30 by the pressure existing in the chamber 15,
In addition, if the clamping of thegasket 25 on the threaded jointing tube 5 is incomplete, so that the blow-by towards the channel 29 and groove 31 occurs, the air will also tend to flow back to the chamber 15 through the groove 31 be cause of the losses of pressure due to the back flow through the channel 29, The right equilibrium between the losses of pressure in said channels 28, 29 can assure the unloading of the device for insufficient damping of the gasket 25, even in the case of absence of the self-closing valve 30. For this reason, it is possible to immediately understand that the device is insufficiently tight, anyhow, situations of risk of deflating of the tire for insufficient tightening do not occur,
Rg.2 showsvthe device after its tightening; after the complete screwing of the device on the valve 5,6 of the tire, and therefore, obtaining the adequate tightening of the gasket 25 through screwing of the body 4 on the valve 5, 6, the device is ready to work. In the condition of Fig.2 the device exactly works as a cap of a traditional tire inflating valve, i.e. the device does not carry out any function, but it is only used for protecting the valve. The tire valve 5, 6 is closed by the self-closing valve core 7, therefore, the air tube is neither connected to the chamber 26, nor to the atmosphere.

Usually, the lamina 18 is bent upwards; this bending is maintained untiJ the pressure in the chamber 20 has reached a sufficiently high value with respect to the value of the pressure existing in the housing 17. (i.e. the atmospheric pressure, since the housing 17 is connected to the atmosphere, as it will more readily understood by referring to following description), therefore, when the pressure value is sufficiently high, the bending is directed downwards. In fact, the bending of the lamina 18 depends on the difference between the pressure in the chamber 20, which successively will be connected to the tire air tube, and the pressure in the housing 17, which will be connected to the atmosphere. If this difference of pressure, which advantageously can be corrected considering the temperature value in the case of balanced measure effected by a bimetal 18, is sufficiently high, the bimetal 18 will bend down wards, for reaching a stable downward bent position shown in Figs 3, 4 representing .the functioning .of the device, otherwise the bimetal 18 will maintain its upward bent configuration.
The subsequent operation consists in loading the device; this operation.takes place (Fig.3) by means of a manual external axial thrust P which causes the axial motion of the external envelope 1 with respect to the threaded body 4 by exceeding the thrust of the spring 9.
Because of the thrust Papplied on the external body of the device (external envelope 1, wail 2) aiso the plunger 11 is moved downwards by the thrust P transmitted to the lamina 18 through the upper wall 2; owing to the thrust P, the lamina 18 is bent downwards just as it would happen if the pressure in the chamber 20 was sufficiently higher than the pressure in the housing 17. This is the loading operation, when the device is set at work, which would happen if the difference between the pressure in the chamber 20, on one hand, and the pressure in the housing 17 and the chamber 15 on the other hand, was sufficiently high. It is remarkable that in this first phase of the transient loading, the difference between the pressure in the chamber 20, on one hand, and the

9
pressure in the chamber 15 and the housing 17 (connected to each other through the duct 14) on the other hand, has not yet happened and stabilised, therefore, the bending of the lamina 18 and the downward motion of the plunger 11 occur only because-of the mechanical thrust P. This new geometrical configuration of me lamina 18 also causes the motion of the valve 22 fitted with a double closing device towards the first position of stability; therefore, the vaive 22 connects the duct 13 to the duct 12 and the chambers 16, 20, and disconnects the jointing between the channel 21 and the housing 17. It is to remembeLthat the chamber 20 extends from the upper surface of the lamina 18 to the chamber 16 external to the bellows 10 with continuity.
In addition, owing to the same thrust P the plunger 11 is moved downwards; therefore, the lower end of the rod of the plunger (inside which the duct 13 is bored) pushes downwards the end of the self-closing valve core 7, which opens to allow the air inside the tube to fill the chamber 26 defined inside the jointing tube 5 of the inflating valve 6.
The gasket 25 is also capable of sealing the rod of the plunger 11 by means of its internal lip only when the plunger 11, the rod of which presents two diameters, is moved towards the low limit stop shown in Fig.3 (loading position). Consequently, if at the beginning of the opening of the self-closing valve core 7, during the downward motion of the plunger 11, the air coming out of the tube fills the chamber 26, the chamber 15, the duct 28, the channel 29, the qroove 31 (and the ducts 12,13, the channel 21, and the chambers 16, 20, since those cavities are connected to each other), in the moment when the plunger 11 has reached its low limit stop, and, therefore, the sealing between the rod of the
plunger 11 and the gasket 25 is allowed, also the separation of the chamber 26
defined inside the jointing tube 5 of the inflating valve 6 takes place from the
chamber 15 located under the plunger 11 and inside the bellows 10. It is remarkable that the sealing on the rod of the plunger 11, which is necessary for

insulating the chambers 26 and 15 when the plunger 11 is found at the low limit stop, can also be obtained by means of a gasket different from the gasket 25. for example, a toroidal gasket integral with the threaded body 4: the solution consisting in integrating the sealing in the same gasket 25 allows the reduction of the axial dimensions.
Once this condition is reached, the pressure existing in the air tube is established in the chamber 26, the ducts 12, 13, and the chambers 16 and 20; vice versa, the atmospheric pressure is established in the chamber 15 and the housing 17 and in the ducts 14. 28, 29 and the groove 31. Two cavities have, therefore, been separated, the first cavity 20 is found over the plunger 11, while the second cavity 15 is located under the plunger 11; this separation is due to the gasket 25 on one hand (sealing on the rod of the plunger 11) and, on the other hand, the bellows 10 (sealing on the plunger 11). When the external thrust P is removed, if the difference between the pressure in the chamber 20 and the pressure in the housing 17 (i.e. between the tube and the atmosphere) is sufficiently high (we remember that the chamber 15, through the internal duct 14, is also connected to the housing 17, which, in this way. is subject to the atmospheric pressure), the lamina 18 will maintain the down ward bent configuration due to the thrust P, even when the same thrust P has been removed, and consequently the connection of the duct 13 to the housing 17 through the channel 21 will be dosed, but the connection of the duct 13 to the duct 12 (and, therefore, of the duct 13 to the chambers 16, 20) through the same channel 21 will be open, thanks to the first position of stability reached by the bistable valve 22 fitted with a double dosing device.
After the releasing of the thrust P, the spring 9 and the air pressure in the chambers 16, 20 move the external envelope 1 back upwards which reaches its original position shown in Fig.4. In this configuration, if the air pressure (air tube pressure) existing in the chamber 20 (eventually corrected considering the temperature value in the case of a balanced measure effected by a bimetal 18), is such as to exert a stress on the upper surface of the lamina 18, the stress

WO 99/61264

11

being sufficient to maintain the lamina 18 bent downwards (in fact, the atmospheric pressure exists in the housing 17); said stress also holds the plunger 11 fastened in its low limit stop, since, owing to difference in the active sections, said stress easily exceeds the thrust due to the air tube pressure on the rod of the plunger 11 and the thrust of the spring 8.
In such a way, the rod of the plunger 11 maintains the self-closing valve core 7 open for assuring the continuous connection between the air tube and the measuring system 18 through both the chamber 26 and the chamber 20, where the air tube pressure exists. Each air escape is obviously prevented by the sealing due to the gaskets 25. 19, 3 and the beliows 10. Consequently, as shown in Fig.4, as long as the tire pressure (eventually corrected considering the temperature value) is maintained at a sufficient value, i.e. above the established threshold value defining the low limit of the correct inflating pressure of the tire, the device will remain loaded, i.e. with the lamina 18 bent down wards and the plunger 11 in its low limit stop; the same device will maintain the connection to the air tube.through the self-dosing valve core 7 It is necessary to specify that the utility of the function attained by the device (i.e. signalling when the tire pressure falls bellow at least one pre-established threshold value) is relative to all normal working conditions, where the deflating of the tire takes place slowly, therefore, in a way difficult to perceive by means of common observation (phenomenon which takes place either be cause of natural causes, (ike an escape through the structure of the same tire, or because of external causes, like small punctures which cause a slow deflating); therefore, the device allows the duration needed for sensing the signal and operating as soon as possible in order to restore the most correct pressure value (and/or repair the eventual puncture for preventing the compulsory stop of the vehicle). Obviously, the device will not offer any practical utility in the case of punctures or other serious phenomena causing the deflating of the tire in such

a quick way that the duration for sensing the signal and acting consequently is insufficient.
Naturally, the pre-established threshold value defining the low limit of the.cor-rect inflating pressure can be defined in such a way to assure that the signalling of the exceeding of the same threshold value occurs when the pressure value in the tire is still sufficiently high to allow the duration needed for sensing the signal and acting in the usual operating situations when the deflating takes place slowly.
When the pressure (eventually corrected considering the temperature value) falis below said pre-established threshold value (or beiow another threshold value lower than the previous), as shown in Fig.5, the lamina 18 will bend up wards. This bending will immediately enable the bistable valve 22 fitted with a double closing device to automatically commute from the first to the second position of stability for closing the connection between the duct 13 and the chambers 16 and 20 (through the channel 21 and the duct 12); vice versa the connection between the chamber 20 and the housing 17 (through the duct 12 and the channel 21) remains open. The housing 17, through the duct 14, is connected to the chamber 15 which, in its turn, is connected to the atmosphere 27 through the duct 28, the channel 29 and the groove 31. The aim to be attained when this situation occurs is the safe dosing of me tire, therefore, the tire is insulated from the environment by means of the self-closing valve core 7 for preventing any air escape through the valve core 7 or the device. For this purpose, the device is so planned that the downward thrust acting on the group of the plunger 11 because of the difference between the pressure in the upper chamber 20 (where the tube pressure exists) and the pressure in the lower chamber 15 (where the environmental pressure exists), when the difference in pressure between the chamber 20 and the housing 17 is capable of maintaining the lamina 18 bent downwards, is so high to widely exceed the upward thrust acting on the plunger 11; this thrust being caused by the valve core 7 stressed upwards by the spring 8, the air tube pressure acting on the rod

WO 99/61264

13

section of the plunger 11 and the elasticity of the bellows 10. In this way, the plunger 11 is guaranteed to remain in the loading position (low limit stop) even in presence of external perturbations (vibrations, forces of inertia, etceteras). The starting of the phenomenon which causes the unloading of the device is due to a change in the tire pressure (eventually corrected considering the temperature vaiue) referred to the atmospheric pressure, said change being capable of bending the lamina 18 upwards, when the pressure in the cavities 17. 14. 15, 28 and 29 still presents the atmospheric value and the pressure in the cavities 16, 20, 12, 21, 13 and 26 presents the air tube value (which has just fallen below the established threshold). In these conditions, the difference between the pressure in the upper chamber 20 (where the tube pressure exists) and the pressure in the lower chamber 15 (where the environmental pressure exists) acting on the plunger 11 is anyway still capable of maintaining the plunger 11 in the loading position (i.e. in the low limit stop): in fact, the planning of the active sections of the plunger 11 and of the relative rod will be chosen in such way that the resultant vector of the various above listed forces acting on the plunger 11 will anyway be directed downwards also for tire pressure values lower than the pre-established threshold value, while, once above said threshold value, the lamina 18 will bend upwards. Since the de vice has been planned for a practical utility in all normal working conditions where the deflating of the tire takes place slowly, at the instant when the tire pressure (eventually corrected considering the temperature) passes to a value lower than the threshold pre-established for this purpose, the lamina 18 will bend immediately upwards, but the resultant of the forces acting on the plunger 11 (the module of which will be changed in its turn, but only by a very small quantity the phenomenon being slow) will keep always directed down wards; furthermore, said resultant will present a value such as to permanently maintain the plunger 11 in the low limit stop, until the pressure in the upper chamber 20 falls considerably. This notable fall occurs as a direct immediate consequence of the upward bending of the lamina 18.

WO 99/61264

14

In fact, the motion towards the second position of stability of the valve 22 fitted with a double dosing device consequent to the modification of the geometrical configuration of the famrna 18 causes a sudden change in the pressures within the various cavities. The jointing between the duct 13 (which remains at the tire pressure together with the chamber 26) and the chambers 16 and 20 (thorough the ducts 21 and 12) is disconnected, while the chambers 20 and 16 are emptied through the same duds 12 and 21, the housing 17 (which now is connected to the channels 21 and 12), the duct 14,.the chamber 15 and the channel 28, the groove 31 and the channel 29 which are directly connected to the atmosphere 27.
In this way, the pressure in the chamber 20 quickly fails, while, because of the losses of pressure wnich hinder the air flow to the atmosphere 27 through the duct 28, the groove 31 and the channel 29, the pressure in the chamber 15 tends to increase (previously the pressure in the chamber 15 presented the atmospheric value). This phenomenon associated with the upward thrust acted on the rod of the plunger 11 by the self-closing valve core 7 stressed by the spring 8 and the bellows 10, causes the sudden upstroke of the plunger 11 towards its tow limit stop.
As soon as the upstroke of the plunger 11 starts, the rod with two diameters disengages from the gasket 25: in this way a direct connection is suddenly created between the chamber 26, which until the self-closing vatve core 7 doses, remains at the tire pressure and is potentially fed by an considerable air flow, and the chamber 15 located under the plunger 11. In this way, the pressure in the chamber 15 immediately reaches the tire pressure value by exerting an upward stress on the plunger 11; said pressure value is maintained until the self-closing vatve core 7 completely closed by reaching the scope of the present invention, while the self-closing valve 23 prevents the air from flowing towards the housing 17, and from this one, through the ducts 21 and 12, the air can reach the chamber 20 situated over the plunger 11, where in the meantime

WO 99/61264
15
the pressure has fallen with respect to the tire value presented before exceeding the threshold.
In this way, the plunger 11, until the self-dosing valve core 7 is completely closed, will be subject to an upward resultant thrust, the resultant thrust being due to the difference between the pressure in the chambers 15 and 20 plus the thrust applied to the needle of the self-dosing valve core 7 stressed by the spring 8 and the thrust of the beltows 10, the resultant thrust being sufficient to move the plunger 11 upwards, even if an identical pressure value should be found in the chambers 15 and 20. In fact, the pressure in the chamber 15 re mains at the tire value, since the outlet flow from the self-closing valve core 7 still open is much higher than the loss flowing towards the atmosphere through the duct 28, the groove 31 and the channel 29: this fact assures that, even if the pressure in the chamber 20 should fall by a small quantity, or, even, revert to the value of the air tube at the moment when the disengagement of the rod of the plunger 11 from the gasket 25 occurs, as it might occur if the self-closing valve 23 was removed, the resultant of the stresses acting on the plunger 11 would anyway be always directed upwards thanks to the elastic action of the spring 8 and the bellows 10.
This fact causes the sudden upstroke of the plunger towards its high limit stop and the closing of the self-closing valve core 7 by obtaining the desired result and the unloading of the device: when the self-dosing valve core 7 closes, both chambers 20 and 15 are suddenly connected to environmental pressure (atmospheric pressure), while the plunger 11 completes its upstroke until it reaches the high limit stop thanks to the elasticity of the bellows 10 (Fig.6). In this way, the tire is immediately insulated from the environment; therefore, the self-closing valve core 7 always performs its function of safety and closing against air escapes through the inflating valve. This fact prevents any risk due to eventual escapes in the device.
If the plunger 11, after the loading phase, remains in the position such as to keep the self-closing valve core 7 open, i.e. in its low limit stop, that means the

WO 99/61264

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pressure in the air tube (eventually corrected considering the temperature value) is higher than the pre-established threshold value defining the low limit of the correct inflating tire pressure; vice versa, when the plunger 11 moves back to the high limit stop {i.e. it unloads) the pressure in the air tube (eventually corrected considering the temperature value) is lower than said pre-estab-iished threshold value, or another pre-defined threshold value lower than the previous one.
ft is, then, sufficient to sense either the bendina of the lamina 18 or the position of the plunger 11 (the stroke of which is of some mm.) for signalling the exceeding or not of the threshold value to the external with known means, the threshold value defining the low limit of the correct tire pressure. For example, a chromatic variation in function of the position of the plunger 11 can be displayed on a transparent visor applied to the wall 2. In addition, the displacement of the plunger 11 (or the change in the geometrical configuration of the lamina 18) can set at work an electrical circuit by means of which the emission of optical andfor acoustic signals can be obtained, said signals being transmitted by induction, or hertzian waves etc. with all its possible combinations. The device can obviously be reloaded indefinite times; all times the condition of exceeding the threshold value will occur it will automatically unload and remain unloaded until subsequent hand loading by assuring that the signal can be received.
Fig.6 shows the device after the falling in the tire pressure; in this case, the components of the device are again in the position of Fig.2.

17
CIaim
1. A device capable of signalling the inflating condition of a tire when screwed onto a jointing tube (5) of an Inflating value (6) that has a self-closing vatve core (7) stressed for closure by a valve spring (8), the claimed device comprising:
a. an external envelope (1);
b. a threaded body (4) shdabty mounted at least partially within end rotating
together with the external envelope (1), which threaded body (4) Is adapted
to be screwed onto the jointing tube (5);
c. a plunger (11) filed with a rod positioned to engage the self-closing valve
core (7), and housing a lamina (18) that varies geometrical configuration from
a resting configuration to a pressured configuration, which variation effects
movement within the rod of a bistable very fitted with a double closing
member (22);
d. a movable sealing member (10) connected to the plunger (11), which
movable sealing member (10) delmfts, with respect to the envelope (1), at
least a first chamber (15) located under the plunger (11). and at least a
second chamber (16. 20) located over the plunger (11); wherein the plunger
(11) Is movabty the second chamber (16, 20) wlh a range of motion of a
magnitude sufficient to cause the opening of the self-closing valve core (7)
from a closed position, said range of motion being limited between:
I. a first limit stop position Into which the plunger (11) Is urged by the
movable sealing member (10), and in which the plunger (11) does not
cause the opening of the self-closing vatve core (7), and
II. a second limit stop position, in which the plunger (11) separates a third
chamber (26) from the first chamber (15) by sealmgly contacting a gasket
(25) and causes the opening of the self-closing vatve core (7); wherein
this second limt stop position is successively maintained only If the
difference between:
I. the pressure In the second chamber (16, 20), the value of which reaches the value in of the tire during the loading phase of the device, and

18
I. the pressure in the first chamber (15), which is connect able to atmospheric pressure Is maintained higher than a first pre-established threshold value, so that a resultent thrust acting on the plunger (11) is higher than the forces of the valve spring (8) and the movable sealing member (10); and
e. means used for signalling the configuration of the lamina (18) or the position of the plunger (11), whereby the device Indicates If the pressure In the tire exceeds or not said first pre-established threshold value.
2.Device as in claim 1, wherein the lamina (18) with variable geometrical configuration acts on the double closing member (22) consisting of a bistable valve (22), the lamina (18) presenting a first position of stability and a second position of stabifty; in which first posiion of stability, the bistable valve (22) connects a first duct (12, 21) to a plunger housing (17) and closes the connection between the first duct (12) and a second duct (13); and in which second position of stability, the bistable vatve (22) connects the second dud (13) to the first duct (21, 12) and closes the connection between a the first duct (12, 21) and the housing (17).
3. Device as In claim 2, wherein the lamina (18) with variable geometrical configuration is a bimetal for which the pressure threshold, at which the commutation of the geometrical configuration occurs, is a function of the
temperature.
4.Device as in claim 1, wherein the movable sealing member (10) comprises a beiows (10) allowing the frldloniess axial translation of the plunger (11) inside the device, and separates a first chamber (15) from a second chamber (16, 20), said first chamber (15) and second chamber (16, 20) being respectively located under and over the plunger (11).
5. Device as in claim 1, wherein en external axial force (P) applied to the external
envelope (1):
a. causes the axial translation of the external housing of the device and
moves the envelope (1) with respect to the threaded body (4) against fi
thrust of a spring (9), so that the envelope (1) passes

10
n. from the frst limit stop position which Is in absence of said force maintained by
the thrust of the spring (9),
Hi. to a second timl stop position, in which the envelope (1) remains only until the external force (P) is released;
b. is transmitted from the well (2) to the lemine (18), and
c. causes both:
tv, the change or the geometrical configuration of the lamina (18) toward? n$
second configuration of stability and, v. the motion of the plunger (11) towards the second limit stop position, h which
the plunger (11) causes the opening of the sef-ctoslng valve core (7), and by
interfering win the gasket (25), separates the third chamber (26) from the frst chamber (15).
6. Device as in claim 1, wherein after the releasing of the force (P), the spring
(9) and the thrust of the air pressure in the second chamber (16, 20) move the external envelope (1) towards the first stable limit stop position.
7. Device as in claim 1, wherein the position of the plunger (11) signals the
exceeding or not of at least a first pre-established threshold pressure value, and wheren the wall (2) is transparent for displaying an indication consisting of a chromatic change as a function of the position of the plunger (11). and the configuration of the lamina (18).
8. Device as in claim 7, wheren the displacement of the plunger (11) and the
change In the geometrical configuration of the lamina (18) set at work an electrical circuit causing the emission of optical and/or acoustic signals.
9. Device as in claim 2, wherein the lamina (18) with variable geometrical
configuration Is connected to a housing (17) by a sealing member (19); and
wherein further the bistable valve (22), through a channel (21), alternative*
connects a first duct (12) to a second duct (13), or to the housing (17)
according to the configuration of stabllly reached by the lamina (18). such
that when the device is unloaded, the lamina (18) maintains a first
configuration in which the plunger (11) does not cause the opening of the
setf-closing vaive core (7), and the chambers (15. 16. 20. 17. 26). the ducts
$

20
and the channels (12,13, 21) communicate with the atmosphere (27). 10. Device as In claim 1 (2), wherein the force necessary to move the plunger
(11) from the first to the second limit stop position is transmitted by said
envelope (1) and wall (2) to plunger (11) through the wal (2), which directly
acts on the lamina (18 and causes the deformation of the lamina (18) to the
second configuration; In this configuration the plunger (11) is located at the
second limit stop position, the bistable value fitted with a double closing
member (22) connects the second duct (13) to the first duct (12), so that
pressure of the tire exists in the third chamber (26), the second duct (13),
the first duct (12) and the second chamber (16, 20), while the atmospheric
pressure exists n the housing (17), a third duct (14) and the first chamber
(15); in which position said second configuration of lamina (18) is maintained
onty If the difference between the pressure In the second chamber (16, 20)
and in the housiig (17) exceeds at least a first pre-established threshold
value; In said condition the deference between the pressure In second
chamber (16, 20) and first chamber (15) Is the same as the difference
between the pressure in second chamber (16, 20) and housing (17); until
said difference in pressure is sufficient to maintain the second configuration
of the lamina (18) the resultant force on the plunger (11) is sufficient to
assure that the plunger (11) is maintained in the second limit stop poslion, so
that the device remains loaded; if said deference In pressure Is, or soon after
decreases, until a value lower than a second and tower pre-established
threshold value, the lamina (18) Instantaneously moves again towards the
first configuration; in such a way, the bistable valve fitted with a double
dosing member (22) intercepts the communication between the first duct
(12) and the second duct (13) and connects the first duct (12) to the housing
(17) which, in Is turn, through third duct (14), the first chamber (15) and the
channels (28, 29), is connected to the atmosphere (27); this causes the
quick felling of the pressure In the second chamber (16, 20) to the
atmospheric value; for this reason the plunger (11) moves again towards the
frsf stabie limit stop poslion; therefore, the lamina (18) indicates if the
7

21
pressure in the tre exceeds or not at least a higher pre-established threshold value and causes the recovery of the plunger (11) to the first limit stop position (unloading condition) In which the plunger (11) does not cause the opening of the self-dosing vatve core (7) which closes again the communication with the Internal part of the tire.
11. Device as In claim 9, wherein the force necessary to move the plunger (11) from the first to the second Iimit stop position during the loading phase Is applied to the envelope (1) and the wad (2) Integral with the envelope (1), said force is transmitted by said envelope (1) and waft (2) to plunger (11) through the wall (2), which directly acts on the lamina (18) with variable geometrical configuration and causes the deformation of the lamina (18) to a second configuration; in this configuration the plunger (11) is located at the second llmft stop position, the bistable double closing member (22) connects the second dud (13) to the first duct (12), so that pressure of the tire exists In second chamber (26), second duct (13), first duct (12) and second chamber (16, 20). while the atmospheric pressure exists In the housing (17). a third duct (14) and in first chamber (15); said second configuration of the lamina (18) can be maintained only f the difference between the pressure In second chamber (16, 20) and housing (17) exceeds at least a first pre-established threshold value; In said condition the difference between the pressure In second chamber (16, 20) and first chamber (15) Is the same as the difference between the pressure in second chamber (18.20) and housing (17); until said difference in pressure Is sufficient to maintain the second configuration of the lamina (18) the resultant on the plunger (11) Is sufficient to assure that the plunger (11) is maintained In the second limit stop position, so that the device remains loaded; If said difference In pressure Is. or soon after decreases, untl a vatue tower than a second and tower pre-established threshold value, the lamina (18) instantaneously moves again towards the first configuration; In such a way, the bistable vatve fitted with a double closing member (22) intercepts the communication between the first duct (12) and the second duct (13) and connects the first duct (12) to the housing
8

22
(17), which, in its turn, through the third duct (14), the first chamber (15) and the channels (28, 29), Is connected to the atmosphere (27); this causes the quick falling of the pressure in the second chamber (16, 20) to the atmospheric value, for this reason the plunger (11) moves again towards the first limit stop position; therefore, the lamina (18) Indicates If the pressure in the tire exceeds or not at feast a higher pre-established threshold value and causes the recovery of the plunger (11) to the first limit stop position (unloading condition) in which the plunger (11) does not cause the opening of the setf-closing valve core (7) which closes again the communication with the internal part of the tire.
12. Device as in claim 9, wherein the lamina (18) with variable geometrical
configuration is a bimetal (18) allowing to change the pressure threshold
which causes the commutation of the configuration tn function of the
temperature.
13. Device as In daft 5, wherein after the releasing of the force (P). the spring
(9) and the thrust of the air pressure existing in the second chamber (16, 20)
move again the external envelope (1) towards the first stable limit stop
position.
14. Device as in claim 1, wherein the displacement of the plunger (11) or the
change in geometrical configuration of the lamina (18) set at work an
electrical circuit by means of which the emission of optical and/or acoustic
signals is obtained to be transmitted via electromagnetic waves.
1. A device capable of signaling the inflating condition of a tire when screwed onto a jointing tube (5) of an Inflating value e (6) that has a self-closing valve core (7) stressed for closure by a valve spring (8), the claimed device comprising:
a. an external envelope (1);
b. a threaded body (4) stidabty mounted at least partially within end rotating
together with the external envelope (1), which threaded body (4) Is adapted
to be screwed onto the jointing tube (5);
c. s plunger (11) filed with 8 rod positioned to engage the self-closing valve
core (7), and housing a lamina (18) that varies geometrical configuration from
a resting configuration to a pressured configuration, which variation effects
movement within the rod of a bistable verve fitted with a double closing
member (22);
d. a movable sealing member (10) comected to the plunger (11), which
movable seating member (10) delmfts, with respect to the envelope (1), at
teast a first chamber (15) located under the plunger (11). and at least a
second chamber (16. 20) located over the plunger (11); wherein the plunger
(11) Is movably the second chamber (16, 20) with a range of motion of a
magnitude sufficient to cause the opening of the self-closing valve core (7)
from a closed position, said range of motion being limited between:
I. a first limit stop position Into which the plunger (11) Is urged by the
movable sealing member (10), and in which the plunger (11) does not
cause the opening of the self-closing valve core (7), and
II. a second limit stop position, in which the plunger (11) separates a third
chamber (26) from the first chamber (15) by steamily contacting a gasket
(25) and causes the opening of the self-closing valve core (7); wherein
this second limit stop position is successively maintained only if the
difference between:
I. the pressure In the second chamber (16, 20), the value of which reaches the value in of the tire during the loading phase of the device, and

I. the pressure in the first chamber (15), which is correctable to atmospheric pressure is maintained higher than a first pro-established threshold value, so that a resultant thrust acting on the plunger (11) is higher than the forces of the valve spring (8) and the movable sealing member (10); and
e. means used for signaling the configuration of the lamina (18) or of the plunger (11), whereby the device indicates if the pressure exceeds or not sated first pre-established threshold value.

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Patent Number

201709

Indian Patent Application Number

IN/PCT/2000/0504/KOL

PG Journal Number

08/2007

Publication Date

23-Feb-2007

Grant Date

23-Feb-2007

Date of Filing

13-Nov-2000

Name of Patentee

BARBANTI ,GIOVANNI,

Applicant Address

ITALY VIA PODGORA,1,1-40033 CASALECCHIO DI RENO,

Inventors:

#	Inventor's Name	Inventor's Address
1	BARBANTI ,GIOVANNI,	ITALY VIA PODGORA,1,1-40033 CASALECCHIO DI RENO,

PCT International Classification Number

B 60C 23/00;23/04

PCT International Application Number

PCT/EP99/03613

PCT International Filing date

1999-05-25

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	98109696.9	1998-05-28	EUROPEAN UNION