Title of Invention	A LOCKING DEVICE FOR AN ELECTRICAL SWITCH AND AN WITHDRAWABLE LOCK WITH LOCKING DEVICE
Abstract	The invention relates to a locking device (81) for an electrical switch (2), which is guided displaceably in a withdrawable rack (1) by means of an actuating shaft (14) and which, with the switch located in a preferred position, in particular an isolating position, can be moved from a release position, in which the switch is displaceable in the withdrawable rack, into a locking position, the locking device (81) in the locking position blocking a displacement of the switch in the withdrawable rack in a predetermined direction (117), and the actuating shaft (14) being capable of being actuated via an actuating crank (13), wherein the actuating crank(13) cannot be removed from the actuating shaft (14) being a part of a traveling drive (15), characterized in that the locking device can only be moved into the locking position if the actuating crank (13) is blocked against actuation.

Title of Invention

A LOCKING DEVICE FOR AN ELECTRICAL SWITCH AND AN WITHDRAWABLE LOCK WITH LOCKING DEVICE

Abstract

The invention relates to a locking device (81) for an electrical switch (2), which is guided displaceably in a withdrawable rack (1) by means of an actuating shaft (14) and which, with the switch located in a preferred position, in particular an isolating position, can be moved from a release position, in which the switch is displaceable in the withdrawable rack, into a locking position, the locking device (81) in the locking position blocking a displacement of the switch in the withdrawable rack in a predetermined direction (117), and the actuating shaft (14) being capable of being actuated via an actuating crank (13), wherein the actuating crank(13) cannot be removed from the actuating shaft (14) being a part of a traveling drive (15), characterized in that the locking device can only be moved into the locking position if the actuating crank (13) is blocked against actuation.

Full Text	Description Locking device and withdrawable rack with a locking device The invention is in the field of electrical switches and relates to a locking device for an electrical switch, which is guided displaceably in a withdrawable rack by means of an actuating shaft and which, with the switch located in a preferred position, in particular an isolating position, can be moved from a release position, in which the switch is displaceable in the withdrawable rack, into a locking position, the locking device in the locking position blocking a displacement of the switch in the withdrawable rack in a predetermined direction, and the actuating shaft being capable of being actuated via an actuating crank. The invention also relates to a withdrawable rack with such a locking device. A locking device of the generic type and a withdrawable rack of the generic type are known, for example, from the document EP 0 842 556 B1. Starting from this known locking device, the invention is based on the object of designing the locking of the switch in its preferred position to be even more reliable. This object is achieved according to the invention by virtue of the fact that the locking device can only be moved into the locking position if the actuating crank is blocked against actuation. Such a design also prevents the actuation of the actuating crank. In an advantageous manner, the risk of damage to the mechanism of the locking device owing to the high leverage forces which act on the actuating shaft via the actuating crank is thus eliminated. One preferred configuration of the novel locking device provides for a means for querying the position of the switch to be provided which, with the switch located in the preferred position, can only be moved from an open position into a blocking position if the actuating crank is blocked against actuation. In a further preferred configuration, the locking device has the following elements: - a means for blocking the actuating shaft, which means is coupled to the means for querying the position of the switch, in order to block the displacement of the switch, - an actuating element (blocking slide), which can be moved from a free position into a blocking position, in order to block the actuation of the actuating crank, - a sensing means, which can be moved from a first position, which corresponds to the blocking position of the blocking slide, into a second position, which corresponds to the free position of the blocking slide, in order to sense the position of the blocking slide, and - a first blocking means, which is coupled to the sensing means by means of a coupling section, in order to block the means for querying the position of the switch, the first blocking means only releasing the means for querying the position of the switch such that it can be moved into its blocking position if the blocking slide is located in its blocking position. In a further configuration, provision is made for the sensing means to be mounted on a carriage which can be displaced by means of the switch. Furthermore, a restraining means can advantageously be provided which, with the switch removed from the withdrawable rack, keeps the sensing means in its first position, which corresponds to the blocking position of the blocking slide. It is advantageous if the means for querying the position of the switch can be stopped in its blocking position. A locking cylinder, which is coupled to the means for querying the position of the switch by means of a cable pull, is preferably used for this purpose. In order, when the switch has been removed once from the withdrawable rack, to prevent a switch from being inserted into the withdrawable rack again, a second blocking means is provided which, with the means for querying the position of the switch stopped in its blocking position and once the switch has been removed from the withdrawable rack, pivots into the movement path of the switch which points in the direction of the preferred position. The novel locking device is preferably associated with the withdrawable rack and, for this purpose, is arranged beneath the electrical switch on the withdrawable rack, in particular by means of a bearing plate. A locking device designed in accordance with the invention is illustrated in figures 1 to 11, in which: figure 1 shows a front side of a switchgear cell with a withdrawable rack in which a low-voltage circuit breaker is arranged, figure 2 shows a traveling drive of the low-voltage circuit breaker with a view of an actuating crank, which has been plugged onto an actuating shaft and can be blocked by means of an actuating element (blocking slide), figure 3 shows the traveling drive shown in figure 2 with a view of a blocking pawl, by means of which the actuating shaft can be stopped, figure 4 shows a perspective illustration of the withdrawable rack with the locking device according to the invention which is arranged beneath the low-voltage circuit breaker on the bottom of the withdrawable rack, figure 5 shows a plan view of the locking device according to the invention, figure 6 shows the locking device according to the invention with a view of its underside, figure 7 shows the withdrawable rack with the locking device in an unlocked first position with the switch removed from the withdrawable rack, figures 8 to 11 show further characteristic positions of the locking device, and figure 12 shows a particular configuration of a means for blocking the actuating shaft. As shown in figure 1, a withdrawable rack 1 is arranged in a switchgear cell of a switchgear cabinet or a switchgear assembly, a low-voltage circuit breaker 2 being arranged displaceably in a known manner in the withdrawable rack 1. The low-voltage circuit breaker 2, which has been inserted in the withdrawable rack 1, has a housing 3 for accommodating a switching pole assembly and a control panel 4, which is fixed to the front side of the housing 3 and forms the front side of the switch and by means of which a switching drive and further parts of the switch are covered. An overcurrent release 5, control and display elements 6 to 10, a manually operated winding lever 11 for tensioning a spring energy store of the switching drive and an actuating crank 13, which can be lowered into an accommodating pocket 12, for actuating an actuating shaft 14 of a traveling drive 15 are arranged on the control panel 4. As shown in figure 2, the traveling drive 15 has a housing 16, which can expediently comprise two shell-like halves, between which gear mechanism parts and further components are arranged. A rotary movement exerted by means of the actuating crank 13 is converted into a rotation of a traveling shaft 17 by means of the actuating shaft 14. For this purpose, a worm is arranged on the actuating shaft 14, which worm is in engagement with a gearwheel. The longitudinal axes of the actuating shaft 14 and the traveling shaft 17 are at right angles with respect to one another. The traveling shaft 17 is not fixedly connected to the traveling drive 15, but is displaceable in a profiled opening 20 of the gearwheel which is matched to the profile of the traveling shaft 17. In this way, the traveling drive 15 can be used for circuit breakers of different sizes and is not tied to a specific position along the traveling shaft 17. Traveling cranks 21 (cf. figure 4) are fitted in a known manner to the ends of the traveling shaft 17, which traveling cranks 21 interact with stationary parts, for example in the way shown schematically in DE 44 20 580 C1 or DE 44 20 581 C1 (in each case in figure 1) . Likewise not illustrated is the fixing of the traveling drive 15 to a circuit breaker, since this is well known to a person skilled in the art. As has already been mentioned, an actuating crank 13 is used for rotating the actuating shaft 14 which is mounted in the housing 16, which actuating crank 13, in contrast to the other known traveling drives (cf. DE 44 20 580 C1 and DE 44 2 0 581 C1, mentioned) , cannot be removed from the actuating shaft 14, but is part of the traveling drive 15. The actuating crank 13 has a hollow shank 22, which is coupled in a rotationally locked fashion to a free end of the actuating shaft 14 and can be displaced on the actuating shaft 14. The hollow shank 22 bears a guide pin 25, which engages in a guide groove 26 provided on the housing 16. Since the guide groove 26 is matched to the guide pin 25, the shank 22 can be displaced along the guide groove 26, but without any possibility of rotation. This is only enabled when the shank 22 has been pulled out completely towards the front, where the guide groove 2 6 opens out into an annular groove in the housing 16. "Annular groove" is in this context understood to mean differently shaped cutouts of the housing 16 which make free rotation of the shank 22 possible. In addition to the shank 22, the actuating crank 13 comprises a crank arm 27, which is connected to the shank 22 (or is produced integrally with said shank) and at whose end an opening for accommodating a grip piece 28 is located. The grip piece 28 can be displaced in the mentioned opening in the direction of an arrow 29 parallel to the shank 22 and can be moved from the inserted rest position shown in figure 3 into a withdrawn working position by the user. In the rest position, the actuating crank 13 therefore needs to be accommodated in the accommodating pocket 12 such that it is lowered so as to be flush. The accommodating pocket 12 belongs to a control panel insert 3 0 (cf. figures 1 and 2) , which is arranged on the lower edge of the control panel 4 of the circuit breaker 2. When the actuating crank 13 is inserted into its rest position, an end face 31 (cf. figure 3) at the end of the shank 22 comes to bear against a supporting ring 32, which is loaded by a stop spring 33. The stop spring 33 is a helical compression spring, which rests on the actuating shaft 14. Then, the user pushes the grip piece 28 through the opening located in the crank arm 27 until it is in a position which is flush with the crank arm 27. The inner end of the grip piece 28 then bears against a stop 34. In this inserted rest position, the user in fact has no possible way of gripping the crank arm because the contour of the accommodating pocket 12 is matched to the crank arm 2 7 with the shank 22 and the grip piece 28. Nevertheless, if required quick access is ensured. This takes place by virtue of the fact that the depth of the accommodating pocket is dimensioned such that it is larger by a certain extent than is required to accommodate said parts. The user can therefore push the crank arm 27 slightly into the accommodating pocket, counter to the force of the stop spring 33. However, the grip piece 28, owing to the fact that it bears against the fixed stop 34, cannot take part in this movement and now protrudes from the crank arm 27 by the same amount. The user can now pull out the grip piece 28 and then the crank arm 27 with the shank 22. In a similar way to in the case of known traveling drives, arranged alongside the actuating crank 13 is a display window 24, in which a display means 35 for the operational position of the circuit breaker in its withdrawable rack can be seen. These positions - operating position, test position and isolating position - relate in a known manner to the relative positions of movable main isolating contacts and auxiliary isolating contacts and therefore, with a given arrangement of these isolating contacts, to the position of the circuit breaker 2 in the associated withdrawable rack 1. Owing to the fact that the traveling cranks 21 (cf. figure 4) at the ends of the traveling shaft 17 engage in a stationary guide of the withdrawable rack 1, the angular position of the gearwheel therefore forms a reliable feature for the mentioned positions. For the purposes of the display device, a control cam is therefore arranged at an end side of the gearwheel (not shown), against which control cam a sensing pin of a two-armed display lever 38 bears under the action of a tension spring 39. The display lever 38, which can be pivoted about a bearing screw 40, therefore moves the control cam into a position of the display means 35 which can be perceived by the user in the display window 24 (cf. figure 2). It is essential here that the user, when actuating the actuating crank 13, can easily identify when the mentioned positions have been reached. For this purpose, the control cam is provided with sections having different slopes, which are designed such that the display means 35 assumes an intermediate position in each case shortly after one of the mentioned positions has been left and then indicates the following position shortly before this position is reached. Owing to the bearing screw 4 0 of the display lever 38 which is positioned relatively close to the control cam, relatively small deflections are converted into easily visible movements of the display means 35 in the display window 24. Owing to a latching slide 41, which is loaded by means of a prestressing spring, the shank 22 is protected against being unintentionally inserted into the housing 16. The latching slide 41 is guided in the front part of the housing 16 and likewise interacts with the end face 31 at the inner end of the shank 22. When the shank 22 is pulled out into its working position, the latching slide 41 springs behind the end face 31 and therefore blocks the insertion of the shank 22. In order to release the shank 22 such that it can be inserted, an actuating tab 43 is available to the user which is arranged such that it protrudes into the accommodating pocket 12 and therefore is only accessible when the actuating crank 13 has been pulled out. The latching slide 41 has an additional function in the central position (test position) of the traveling drive 15. In contrast to the operating position and isolating position, this does not manifest itself for the user by a noticeable resistance at the actuating crank owing to end stops having been reached. In order that, nevertheless, the user can insert the actuating crank 13 only when the test position has been reached precisely, the latching slide 41 is provided with a tongue 44, which emerges laterally at the housing 16 if the actuating tab 43 is operated and a window opening 3 8a, which is arranged in the display lever 38, is opposite the tongue 44. In order to deny the user access to the actuating crank 13, when the crank arm 2 7 has been lowered into the accommodating pocket 12, the shank 22 of the actuating shaft can be fixed axially by a first blocking mechanism. This takes place owing to a first blocking element in the form of a blocking lever 45 in conjunction with a blocking groove 46, which is arranged in the shank 22 of the actuating crank and is delimited in the axial direction of the switch. In this case, the blocking lever 45 is correspondingly connected to a first actuating element in the form of a blocking slide 47, as is described in DE 44 20 580 C1. If the preconditions exist for the traveling drive 15 to be capable of being actuated without any risk to the user, the blocking lever 45 is lifted by the blocking slide 47 corresponding to an arrow 4 7a shown in figure 1, a blocking tab 48 of the blocking lever 45 being pulled out of the blocking groove 46 of the shank 22. Conversely, it is only possible to switch the circuit breaker 2 on when the actuating crank 13 has again been inserted into its rest position in the accommodating pocket 12 and therefore the blocking tab 4 8 on the blocking lever 4 5 can again enter the blocking groove 46. As shown in figure 3, the traveling drive 15 has a second blocking mechanism for blocking the actuation of the actuating shaft 14. This second blocking mechanism serves the purpose of preventing a displacement of the switch in the withdrawable rack by means of cylinder locks 49, 50. This second blocking mechanism also fixes the shank 22 of the actuating crank 13 in its axial direction 24 if the second blocking mechanism is activated in blocking fashion and if the crank arm 27 of the actuating crank has been lowered into the accommodating pocket 12. This takes place by means of a second blocking element, in the form of a blocking pawl 52, in conjunction with a second blocking groove 53, which is arranged in the shank 22 of the actuating crank and is likewise delimited in the axial direction 24 of the shank 22. The blocking pawl 52 is in the form of a stamped metal part and is guided displaceably on stop faces on the traveling drive in the direction of the arrow 54 at right angles to the shank 22. In addition to a blocking tab 55, which is integrally formed on the side facing the shank 22, it has a window-like opening 56, from one of whose inner walls a first retaining pin 57, which runs parallel to the displacement direction 54 of the blocking pawl, for a pretensioning spring 58 is integrally formed. A first arm 59 of a second actuating element 60, which is held on the traveling drive displaceably in the displacement direction 54 of the blocking pawl, protrudes into the window-like opening 56 of the blocking pawl 52. A cylindrical pin 61, which passes through inner walls, which run at right angles to the displacement direction 54, of the actuating element 60 and fixing lugs (opposite these walls) of the traveling drive in the region of corresponding through- holes, is used for holding this second actuating element 60 on the traveling drive 15. In order to axially fix the inserted pin, the pin has a tapered section 62, into which a sprung tab 63 of the actuating element 60 snaps. In order to dismantle the actuating element 60, this tab 63 can be lifted out of the tapered section 62 of the pin 61 by means of a screwdriver or a comparably narrow tool and the pin can therefore be released such that it can be pulled out. A second retaining pin 64 for the pretensioning spring 58 is integrally formed on the first arm 59 of the second actuating element 60. A second arm 65 of the actuating element 60, under the force of a resetting spring 66, which is supported on a first supporting face 61 of one of the housing halves of the traveling drive, bears against a second supporting face 68 of this housing half. In order to guide the resetting spring 66, one supporting face 67 and the actuating element 60 are provided with in each case one retaining pin 69, 70. A first cylinder lock 49 (illustrated schematically) is used for controlling the actuating element 60. When this first cylinder lock 49 is closed, a tab (not illustrated) acts in the direction of the arrow 71 on the second arm 65 and displaces the actuating element 60 and the blocking pawl 52, which is coupled to the actuating element 60 via the pretensioning spring 58, counter to the force of the resetting spring 66 from an OFF position into an ON position in the direction of the shank 22 of the actuating crank. When the shank 22 has been inserted completely, i.e. when the crank arm 27 has been lowered into its accommodating pocket, the second blocking groove 53 of the shank 22 is opposite the blocking tab 55 of the blocking pawl 52, with the result that said blocking tab 55 can enter the blocking groove 53. When attempting to pull the crank arm 27 out of the accommodating pocket 12, one side face of the blocking groove 53 comes to bear against a stop face 72 of the blocking tab 55 and therefore indicates to the operating personnel that blocking of the traveling drive is taking place. In this case, even a slight resistance is sufficient for indicating blocking of the traveling drive. The second actuating element 60, in contrast to the first actuating element 47 (blocking slide) of the first blocking mechanism, can be displaced from its OFF position into its ON position even when the crank arm 27 has not or has not yet been completely lowered into the accommodating pocket 12. With the shank 22 completely pulled out, the blocking pawl 52 is likewise raised when the actuating element 60 is raised and therefore protrudes into the movement path of the shank 22. When the shank is pushed in, the end face 31 of the shank 22 slides over a sliding face 73 of the blocking tab 55 of the blocking pawl and pushes the blocking pawl 52, counter to the force of the pretensioning spring 58, out of the movement path of the shank. Then, the blocking tab 55 slides along a flattened outer section 74 of the shank until it latches into the blocking groove 53. For the alternative actuation of the blocking pawl 52, the second actuating element is coupled to a third actuating element 75 in the form of a two-armed lever. For the coupling process, the second actuating element 60 has a U-shaped cutout 76 at the free end of its first arm 59, a first arm 77 of the two-armed lever engaging in said cutout 76. This two-armed lever is capable of rotating about a stationary bearing screw (not illustrated), which passes through a hole 78 of the third actuating element 75. The second lever arm 79 of the third actuating element 75 can be actuated by means of a pawl of the cylinder lock 50 in the direction of the arrow 80. As shown in figure 4, the locking device 81 according to the invention is fixed beneath the low-voltage circuit breaker 2 to the bottom of the withdrawable rack 1. As shown in figures 5 and 6, the locking device 81 has a bearing plate 82, which, on one side, with a bent-back portion (not visible in the figures) passes through the bottom 83 of the withdrawable rack and which, on its opposite side, is fixed to the bottom 83 of the withdrawable rack by means of a fixing means 84 in the form of a screw. The bearing plate 82 has supporting faces 86, 87, 88, which are bent back at right angles to its bottom face 85 and are used for holding and guiding further elements of the locking device. For example, two hexagon bolts 89, 90 are mounted in rotatable fashion on a first bent-back supporting face 86 and a second bent-back supporting face 87, in each case one lever 91, 92 being held such that it is fixed against rotation on said hexagon bolts 89, 90. The two levers 91, 92 are connected by means of a rod assembly 93. A cable pull 94, which can be actuated by means of a further cylinder lock 95, acts on one lever 91. The rod assembly 93 is loaded by a second resetting spring 96, which holds the two levers 91, 92 and therefore the two bolts 89, 90 in a rest position when the cylinder lock 95 is unlocked. While a means 97 for querying the position of the switch in the form of two stop levers is held such that it is fixed against rotation on one of the hexagon bolts 89, the other of the two levers 92 is provided with a means 98 for blocking the actuating shaft 14 in the form of a cam disk. In this case, the cam disk acts in the direction of the arrow 71 on the second arm 65 of the second actuating element 60 (cf. figure 3) . The means 97 for querying the position of the switch and the means 98 for blocking the actuating shaft 14 in an open position, which corresponds to the unactuated OFF position of the second actuating element 60, are located in the rest position of the rod assembly 93. A carriage 99, which is bent in the form of a U, is held displaceably on the third bent-back supporting face 88. For this purpose, the third supporting face 8 8 is provided with a slot 100 (cf. figure 7), in which two bolts 101, 102, which are connected to the carriage 99, are guided displaceably. In this case, one of the two bolts 101 passes through the two lateral guide faces 103, 104, which run parallel to the third supporting face, of the carriage, which is bent in the form of a U. A restraining means 105 in the form of a two-armed lever is mounted pivotably on this bolt 101. In this case, one lever arm 106 extends in the form of a bent-back portion which runs parallel to the guide faces of the carriage bent in the form of a U (cf. figure 8) in the direction of a rear wall 107 of the withdrawable rack 1 (cf. figure 4). The second lever arm 108, which extends in the direction of the open side 109 (cf. figure 4) of the withdrawable rack 1 in a plane which runs substantially parallel to the bottom 110 of the carriage bent in the form of a U has a bent-back portion 111, which points in the direction of the bottom 110, at its free end (cf. figure 8). Two bearing arms 112, 113 (cf. figure 8), which run parallel to the guide faces of the carriage bent in the form of a U and have a distance from one another such that the outer width of the restraining means is matched to the inner width of the carriage bent in the form of a U, are used for pivotably mounting the restraining means 105 on the bolt 101. A third resetting spring 114 in the form of a helical compression spring is supported between the bottom 110 of the carriage 99 and the free end of the first lever arm 106. The second 102 of the bolts acts as a first abutment for a fourth resetting spring 115, which is in the form of a tension spring and whose second abutment is formed by a pin 116. In this case, the pin 116 protrudes away from the outwardly pointing, third supporting face 88, mounted in front of the first bolt 101 in the insertion direction 117. The guide face 103, which is opposite this third supporting face 88, of the carriage 99 bent in the form of a U has a tab 118, which protrudes into the movement path of the low-voltage circuit breaker 2 and is used for guiding the carriage 99 along with the switch when a specific insertion position is reached. A sensing means 119 in the form of a further two-armed lever is mounted pivotably on the first bolt 101 between the carriage 99 and the restraining means 105. This sensing means 119 serves the purpose of sensing the position of the actuating element 47 (of the blocking slide). Two guide slits 120, 121 are used for axially positioning the sensing element 119, of which guide slits a first 120 is provided in a rear bent-back portion 122 of the carriage 99 and the second 121 is provided in the second lever arm 108 of the restraining means 105 and in the bent-back portion 111 thereof. While the upwardly pointing edge of the end of one lever arm 123 of the sensing means 119 is opposite an actuating face 124 (cf. figure 9) of the first actuating element 47 (blocking slide), a bow 126 of a lever mechanism 127 bears against the upwardly pointing edge of the free end of the other lever arm 125. A first blocking means 128 in the form of a blocking flap, which is bent in the form of a U, is held such that it is fixed against rotation on the lever mechanism 127. The blocking flap is held by a fifth resetting spring 129 in a rest position, in which it covers the two stop levers which form the means for querying the position of the switch 97 and, as a result, holds them in their open position (cf. figure 9). The hexagon bolt 8 9 bears, in addition to the means 97 for querying the position of the switch, a second blocking means 13 0 in the form of a frame-like flap, which bears against retaining tabs 133, 134 of the two stop levers by means of an edge 131 under the force of a second prestressing spring 132. Figure 7 shows the locking device 81 in its unlocked release position with the switch removed from the withdrawable rack. In this case, the means 98 (cam disk) for blocking the actuating shaft 14 is located in its OFF position, and the means 97 (stop levers) for querying the position of the switch 97 is located in its open position. Owing to the fact that there is no low- voltage circuit breaker in the withdrawable rack, there is also no first actuating element (blocking slide) acting on the one lever arm 123 of the sensing means 119. In this case, the forces of the fifth resetting spring 129, which acts on the first blocking means 128 (blocking flap) , and of the third resetting spring 114 (cf. figure 5), which acts on the restraining means 105, are dimensioned such that the first lever arm 123 of the sensing means 119 is pivoted downwards into a first position corresponding to the blocking position of the first actuating element 47 (blocking slide) and the first blocking means 128 (blocking flap) is therefore pivoted upwards such that the means 97 for querying the position of the switch is released such that it can be moved into its blocking position. Figure 8 shows the locking device 81 in its locked locking position with the switch removed from the withdrawable rack. In contrast to the position as illustrated in figure 7, in this case the means 97 for querying the position of the switch (stop levers) is moved into its blocking position by the actuation of the cylinder lock 95. In this case, the second blocking means 130 (frame-like flap) is released by the retaining tabs 133, 134 of the stop levers and is therefore pivoted upwards such that a front edge 135 protrudes into the movement path 13 6 of the switch which points in the insertion direction. Once a switch has been removed from the withdrawable rack, renewed insertion of a switch is therefore prevented when the locking device is locked. In this locking position, the means 98 for blocking the actuating shaft 14 is located in a position in which the actuating element 60 is raised such that the blocking pawl 52 is located in its ON position and the shank 22 is stopped in its axial direction. As an alternative to the second blocking means, a third blocking means, which is coupled to the means 97 for querying the position of the switch, can be provided such that, when the locking device is located in the locking position, removal of a switch from the withdrawable rack is also prevented. For this purpose, as shown in figure 12, a bent-back portion 138 is also provided on the means 13 7 (in the form of a cam disk) for blocking the actuating shaft, which bent-back portion 13 8 runs at right angles to the movement path of the switch and, when the switch is located in the isolating position in the withdrawable rack and the locking device is located in its locking position, is opposite a stop face 139 of the second actuating element 60 and therefore blocks removal of the switch. When the locking device is located in its locking position, the same bent-back portion 138 is opposite a stop face 140 (cf. figure 3) of the housing 16 of the traveling drive 15 of a switch 1 if an attempt is made to insert the switch 1 into the withdrawable rack when the locking device is located in its locking position and therefore prevents the insertion. Figure 9 shows the locking device 81 in its release position, in which it cannot be locked since the low-voltage circuit breaker is located in an intermediate position outside of the preferred isolating position. In this intermediate position, the first actuating element 47 is in its free position, i.e. in its upwardly displaced position, since the preferred position, namely the isolating position of the switch in the withdrawable rack, has not yet been reached. The lever arm 106 of the restraining means 105 is pivoted by the inserted switch and the spring force of the third resetting spring 114 is blocked such that the first blocking means 128 and the lever arm 125 are held in their rest position under the force of the fifth resetting spring 129, in which rest position the means 97 for querying the position of the switch (stop levers) is stopped in its open position. A cam 136 is formed on the lever arm 106 of the restraining means 105 such that the sensing means 119 and the first actuating element 47 (blocking slide) are reliably associated with one another irrespective of the position of the first actuating element 47. Figure 10 shows the locking device 81 with the switch located in the isolating position in its unlocked release position, in which, however, the means 97 for querying the position of the switch is released such that it can be moved into its blocking position. This release is brought about by the first actuating element 47 (blocking slide) being moved into its blocking position, i.e. by the blocking slide being lowered. Such lowering of the blocking slide, as has already been explained, is only possible, however, if the crank arm 27 has been recessed completely into the accommodating pocket 12 and therefore an actuation of the actuating crank 13 is prevented (cf. figure 2). Figure 11 shows the locking device 81 with the switch located in the isolating position in its locking position, in which the means 97 for querying the position of the switch is moved from its open position (cf. figure 10) into its blocking position. In its blocking position, the means 97 protrudes into the movement path of the switch, with the result that a further displacement of the switch beyond its isolating position in the direction of the test and operating position is stopped. In this case too, the blocking pawl 52 is caused to move into its ON position owing to the rotation of the means 98 (cam disk) for blocking the actuating shaft, with the result that the shank 22 is stopped in its axial direction in this case, too. Figure 7 WE CLAIM : 1. A locking device (81) for an electrical switch (2), which is guided displaceably in a withdrawable rack (1) by means of an actuating shaft (14) and which, with the switch located in a preferred position, in particular an isolating position, can be moved from a release position, in which the switch is displaceable in the withdrawable rack, into a locking position, the locking device (81) in the locking position blocking a displacement of the switch in the withdrawable rack in a predetermined direction (117), and the actuating shaft (14) being capable of being actuated via an actuating crank (13), wherein the actuating crank(13) cannot be removed from the actuating shaft (14) being a part of a traveling drive (15), characterized in that the locking device can only be moved into the locking position if the actuating crank (13) is blocked against actuation. 2. The locking device as claimed in claim 1, wherein a means (97) for querying the position of the switch (2) is provided which, with the switch located in the preferred position, can only be moved from an open position into a blocking position if the actuating crank (13) is blocked against actuation. 3. The locking device as claimed in claim 2, wherein a means (98) for blocking the actuating shaft (14), which means (98) is coupled to the means (97) for querying the position of the switch, is provided in order to block the displacement of the switch (2), an actuating element (47), which can be moved from a free position into a blocking position, is provided in order to block the actuation of the actuating crank (13), a sensing means (119), which can be moved from a first position, which corresponds to the blocking position of the actuating element, into a second position, which corresponds to the free position of the actuating element, is provided in order to sense the position of the actuating element (47), and a first blocking means (128), which is coupled to the sensing means (119) by means of a coupling section, is provided in order to block the means (97) for querying the position of the switch, the first blocking means (128) only releasing the means (97) for querying the position of the switch such that it can be moved into its blocking position if the actuating element (47) is located in its blocking position. 4. The locking device as claimed in claim 3, wherein the sensing means (119) is mounted on a carriage (99) which can be displaced by means of the switch (2). 5. The locking device as claimed in claims 3 or 4, wherein a restraining means (105) is provided which, with the switch (2) removed from the withdrawable rack (1) , keeps the sensing means (119) in its first position, which corresponds to the blocking position of the actuating element (47). 6. The locking device as claimed in one of claims 2 to 5, wherein the means (97) for querying the position of the switch can be stopped in its blocking position. 7. The locking device as claimed in claim 6, wherein a locking cylinder (95), which is coupled to the means (97) for querying the position of the switch by means of a cable pull (94), is used for stopping the means (97) for querying the position of the switch in its blocking position. 8. The locking device as claimed in claim 6, wherein a second blocking means (130) is provided which, with the means (97) for querying the position of the switch stopped in its blocking position and once the switch (2) has been removed from the withdrawable rack (1), pivots into the movement path of the switch which points in the direction of the preferred position. 9. The locking device as claimed in claim 6, wherein a third blocking means (138) is provided which, when the means (97) for querying the position of the switch is moved into its blocking position, pivots into the movement path of the switch. 10. A withdrawable rack (1) with a locking device (81) for an electrical switch (2) , which is guided displaceably in the withdrawable rack by means of an actuating shaft (14), the locking device (81) is designed as claimed in one of claims 1 to 9. 11. The withdrawable rack as claimed in claim 10, the locking device (81) has a bearing plate (82) for arranging the locking device on the withdrawable rack (1) beneath the switch (2). ABSTRACT TITLE A LOCKING DEVICE FOR AN ELECTRICAL SWITCH AND AN WITHDRAWABLE LOCK WITH LOCKING DEVICE" The invention relates to a locking device (81) for an electrical switch (2), which is guided displaceably in a withdrawable rack (1) by means of an actuating shaft (14) and which, with the switch located in a preferred position, in particular an isolating position, can be moved from a release position, in which the switch is displaceable in the withdrawable rack, into a locking position, the locking device (81) in the locking position blocking a displacement of the switch in the withdrawable rack in a predetermined direction (117), and the actuating shaft (14) being capable of being actuated via an actuating crank (13), wherein the actuating crank(13) cannot be removed from the actuating shaft (14) being a part of a traveling drive (15), characterized in that the locking device can only be moved into the locking position if the actuating crank (13) is blocked against actuation.

Full Text

Description
Locking device and withdrawable rack with a locking device
The invention is in the field of electrical switches and
relates to a locking device for an electrical switch, which is
guided displaceably in a withdrawable rack by means of an
actuating shaft and which, with the switch located in a
preferred position, in particular an isolating position, can be
moved from a release position, in which the switch is
displaceable in the withdrawable rack, into a locking position,
the locking device in the locking position blocking a
displacement of the switch in the withdrawable rack in a
predetermined direction, and the actuating shaft being capable
of being actuated via an actuating crank.
The invention also relates to a withdrawable rack with such a
locking device.
A locking device of the generic type and a withdrawable rack of
the generic type are known, for example, from the document
EP 0 842 556 B1.
Starting from this known locking device, the invention is based
on the object of designing the locking of the switch in its
preferred position to be even more reliable.
This object is achieved according to the invention by virtue of
the fact that the locking device can only be moved into the
locking position if the actuating crank is blocked

against actuation. Such a design also prevents the actuation of
the actuating crank. In an advantageous manner, the risk of
damage to the mechanism of the locking device owing to the high
leverage forces which act on the actuating shaft via the
actuating crank is thus eliminated.
One preferred configuration of the novel locking device
provides for a means for querying the position of the switch to
be provided which, with the switch located in the preferred
position, can only be moved from an open position into a
blocking position if the actuating crank is blocked against
actuation.
In a further preferred configuration, the locking device has
the following elements:
- a means for blocking the actuating shaft, which means is
coupled to the means for querying the position of the switch,
in order to block the displacement of the switch,
- an actuating element (blocking slide), which can be moved
from a free position into a blocking position, in order to
block the actuation of the actuating crank,
- a sensing means, which can be moved from a first position,
which corresponds to the blocking position of the blocking
slide, into a second position, which corresponds to the free
position of the blocking slide, in order to sense the position
of the blocking slide, and
- a first blocking means, which is coupled to the sensing means
by means of a coupling section, in order to block the means for
querying the position of the switch,
the first blocking means only releasing the means for
querying the position of the switch such that it can be moved
into its blocking position if the blocking slide is located in
its blocking position.

In a further configuration, provision is made for the sensing
means to be mounted on a carriage which can be displaced by
means of the switch.
Furthermore, a restraining means can advantageously be provided
which, with the switch removed from the withdrawable rack,
keeps the sensing means in its first position, which
corresponds to the blocking position of the blocking slide.
It is advantageous if the means for querying the position of
the switch can be stopped in its blocking position. A locking
cylinder, which is coupled to the means for querying the
position of the switch by means of a cable pull, is preferably
used for this purpose.
In order, when the switch has been removed once from the
withdrawable rack, to prevent a switch from being inserted into
the withdrawable rack again, a second blocking means is
provided which, with the means for querying the position of the
switch stopped in its blocking position and once the switch has
been removed from the withdrawable rack, pivots into the
movement path of the switch which points in the direction of
the preferred position.
The novel locking device is preferably associated with the
withdrawable rack and, for this purpose, is arranged beneath
the electrical switch on the withdrawable rack, in particular
by means of a bearing plate.
A locking device designed in accordance with the invention is
illustrated in figures 1 to 11, in which:

figure 1 shows a front side of a switchgear cell with a
withdrawable rack in which a low-voltage circuit
breaker is arranged,
figure 2 shows a traveling drive of the low-voltage circuit
breaker with a view of an actuating crank, which has
been plugged onto an actuating shaft and can be
blocked by means of an actuating element (blocking
slide),
figure 3 shows the traveling drive shown in figure 2 with a
view of a blocking pawl, by means of which the
actuating shaft can be stopped,
figure 4 shows a perspective illustration of the withdrawable
rack with the locking device according to the
invention which is arranged beneath the low-voltage
circuit breaker on the bottom of the withdrawable
rack,
figure 5 shows a plan view of the locking device according to
the invention,
figure 6 shows the locking device according to the invention
with a view of its underside,
figure 7 shows the withdrawable rack with the locking device
in an unlocked first position with the switch
removed from the withdrawable rack,
figures 8 to 11 show further characteristic positions of the
locking device, and
figure 12 shows a particular configuration of a means for
blocking the actuating shaft.
As shown in figure 1, a withdrawable rack 1 is arranged in a
switchgear cell of a switchgear cabinet or a switchgear
assembly, a low-voltage circuit breaker 2 being arranged
displaceably in a known manner in the withdrawable rack 1. The
low-voltage circuit breaker 2, which has

been inserted in the withdrawable rack 1, has a housing 3 for
accommodating a switching pole assembly and a control panel 4,
which is fixed to the front side of the housing 3 and forms the
front side of the switch and by means of which a switching
drive and further parts of the switch are covered. An
overcurrent release 5, control and display elements 6 to 10, a
manually operated winding lever 11 for tensioning a spring
energy store of the switching drive and an actuating crank 13,
which can be lowered into an accommodating pocket 12, for
actuating an actuating shaft 14 of a traveling drive 15 are
arranged on the control panel 4.
As shown in figure 2, the traveling drive 15 has a housing 16,
which can expediently comprise two shell-like halves, between
which gear mechanism parts and further components are arranged.
A rotary movement exerted by means of the actuating crank 13 is
converted into a rotation of a traveling shaft 17 by means of
the actuating shaft 14. For this purpose, a worm is arranged on
the actuating shaft 14, which worm is in engagement with a
gearwheel. The longitudinal axes of the actuating shaft 14 and
the traveling shaft 17 are at right angles with respect to one
another. The traveling shaft 17 is not fixedly connected to the
traveling drive 15, but is displaceable in a profiled opening
20 of the gearwheel which is matched to the profile of the
traveling shaft 17. In this way, the traveling drive 15 can be
used for circuit breakers of different sizes and is not tied to
a specific position along the traveling shaft 17. Traveling
cranks 21 (cf. figure 4) are fitted in a known manner to the
ends of the traveling shaft 17, which traveling cranks 21
interact with stationary parts, for example in the way shown
schematically in DE 44 20 580 C1 or DE 44 20 581 C1 (in each
case in figure 1) . Likewise not illustrated is the fixing of
the traveling drive 15 to a circuit breaker, since this is well
known to a person skilled in the art.

As has already been mentioned, an actuating crank 13 is used
for rotating the actuating shaft 14 which is mounted in the
housing 16, which actuating crank 13, in contrast to the other
known traveling drives (cf. DE 44 20 580 C1 and
DE 44 2 0 581 C1, mentioned) , cannot be removed from the
actuating shaft 14, but is part of the traveling drive 15. The
actuating crank 13 has a hollow shank 22, which is coupled in a
rotationally locked fashion to a free end of the actuating
shaft 14 and can be displaced on the actuating shaft 14.
The hollow shank 22 bears a guide pin 25, which engages in a
guide groove 26 provided on the housing 16. Since the guide
groove 26 is matched to the guide pin 25, the shank 22 can be
displaced along the guide groove 26, but without any
possibility of rotation. This is only enabled when the shank 22
has been pulled out completely towards the front, where the
guide groove 2 6 opens out into an annular groove in the housing
16. "Annular groove" is in this context understood to mean
differently shaped cutouts of the housing 16 which make free
rotation of the shank 22 possible.
In addition to the shank 22, the actuating crank 13 comprises a
crank arm 27, which is connected to the shank 22 (or is
produced integrally with said shank) and at whose end an
opening for accommodating a grip piece 28 is located. The grip
piece 28 can be displaced in the mentioned opening in the
direction of an arrow 29 parallel to the shank 22 and can be
moved from the inserted rest position shown in figure 3 into a
withdrawn working position by the user.
In the rest position, the actuating crank 13 therefore needs to
be accommodated in the accommodating pocket 12 such that it is
lowered so as to be flush. The accommodating pocket 12 belongs
to a control panel insert 3 0 (cf.

figures 1 and 2) , which is arranged on the lower edge of the
control panel 4 of the circuit breaker 2. When the actuating
crank 13 is inserted into its rest position, an end face 31
(cf. figure 3) at the end of the shank 22 comes to bear against
a supporting ring 32, which is loaded by a stop spring 33. The
stop spring 33 is a helical compression spring, which rests on
the actuating shaft 14. Then, the user pushes the grip piece 28
through the opening located in the crank arm 27 until it is in
a position which is flush with the crank arm 27. The inner end
of the grip piece 28 then bears against a stop 34.
In this inserted rest position, the user in fact has no
possible way of gripping the crank arm because the contour of
the accommodating pocket 12 is matched to the crank arm 2 7 with
the shank 22 and the grip piece 28. Nevertheless, if required
quick access is ensured. This takes place by virtue of the fact
that the depth of the accommodating pocket is dimensioned such
that it is larger by a certain extent than is required to
accommodate said parts. The user can therefore push the crank
arm 27 slightly into the accommodating pocket, counter to the
force of the stop spring 33. However, the grip piece 28, owing
to the fact that it bears against the fixed stop 34, cannot
take part in this movement and now protrudes from the crank arm
27 by the same amount. The user can now pull out the grip piece
28 and then the crank arm 27 with the shank 22.
In a similar way to in the case of known traveling drives,
arranged alongside the actuating crank 13 is a display window
24, in which a display means 35 for the operational position of
the circuit breaker in its withdrawable rack can be seen. These
positions - operating position, test position and isolating
position - relate in a known manner to the relative

positions of movable main isolating contacts and auxiliary
isolating contacts and therefore, with a given arrangement of
these isolating contacts, to the position of the circuit
breaker 2 in the associated withdrawable rack 1. Owing to the
fact that the traveling cranks 21 (cf. figure 4) at the ends of
the traveling shaft 17 engage in a stationary guide of the
withdrawable rack 1, the angular position of the gearwheel
therefore forms a reliable feature for the mentioned positions.
For the purposes of the display device, a control cam is
therefore arranged at an end side of the gearwheel (not shown),
against which control cam a sensing pin of a two-armed display
lever 38 bears under the action of a tension spring 39. The
display lever 38, which can be pivoted about a bearing screw
40, therefore moves the control cam into a position of the
display means 35 which can be perceived by the user in the
display window 24 (cf. figure 2). It is essential here that the
user, when actuating the actuating crank 13, can easily
identify when the mentioned positions have been reached. For
this purpose, the control cam is provided with sections having
different slopes, which are designed such that the display
means 35 assumes an intermediate position in each case shortly
after one of the mentioned positions has been left and then
indicates the following position shortly before this position
is reached. Owing to the bearing screw 4 0 of the display lever
38 which is positioned relatively close to the control cam,
relatively small deflections are converted into easily visible
movements of the display means 35 in the display window 24.
Owing to a latching slide 41, which is loaded by means of a
prestressing spring, the shank 22 is protected against being
unintentionally inserted into the housing 16. The latching
slide 41 is guided in the front part of the housing 16 and
likewise

interacts with the end face 31 at the inner end of the shank
22. When the shank 22 is pulled out into its working position,
the latching slide 41 springs behind the end face 31 and
therefore blocks the insertion of the shank 22. In order to
release the shank 22 such that it can be inserted, an actuating
tab 43 is available to the user which is arranged such that it
protrudes into the accommodating pocket 12 and therefore is
only accessible when the actuating crank 13 has been pulled
out.
The latching slide 41 has an additional function in the central
position (test position) of the traveling drive 15. In contrast
to the operating position and isolating position, this does not
manifest itself for the user by a noticeable resistance at the
actuating crank owing to end stops having been reached. In
order that, nevertheless, the user can insert the actuating
crank 13 only when the test position has been reached
precisely, the latching slide 41 is provided with a tongue 44,
which emerges laterally at the housing 16 if the actuating tab
43 is operated and a window opening 3 8a, which is arranged in
the display lever 38, is opposite the tongue 44.
In order to deny the user access to the actuating crank 13,
when the crank arm 2 7 has been lowered into the accommodating
pocket 12, the shank 22 of the actuating shaft can be fixed
axially by a first blocking mechanism. This takes place owing
to a first blocking element in the form of a blocking lever 45
in conjunction with a blocking groove 46, which is arranged in
the shank 22 of the actuating crank and is delimited in the
axial direction of the switch. In this case, the blocking lever
45 is correspondingly connected to a first actuating element in
the form of a blocking slide 47, as is described in
DE 44 20 580 C1. If the preconditions exist for the traveling
drive 15

to be capable of being actuated without any risk to the user,
the blocking lever 45 is lifted by the blocking slide 47
corresponding to an arrow 4 7a shown in figure 1, a blocking tab
48 of the blocking lever 45 being pulled out of the blocking
groove 46 of the shank 22. Conversely, it is only possible to
switch the circuit breaker 2 on when the actuating crank 13 has
again been inserted into its rest position in the accommodating
pocket 12 and therefore the blocking tab 4 8 on the blocking
lever 4 5 can again enter the blocking groove 46.
As shown in figure 3, the traveling drive 15 has a second
blocking mechanism for blocking the actuation of the actuating
shaft 14. This second blocking mechanism serves the purpose of
preventing a displacement of the switch in the withdrawable
rack by means of cylinder locks 49, 50. This second blocking
mechanism also fixes the shank 22 of the actuating crank 13 in
its axial direction 24 if the second blocking mechanism is
activated in blocking fashion and if the crank arm 27 of the
actuating crank has been lowered into the accommodating pocket
12. This takes place by means of a second blocking element, in
the form of a blocking pawl 52, in conjunction with a second
blocking groove 53, which is arranged in the shank 22 of the
actuating crank and is likewise delimited in the axial
direction 24 of the shank 22. The blocking pawl 52 is in the
form of a stamped metal part and is guided displaceably on stop
faces on the traveling drive in the direction of the arrow 54
at right angles to the shank 22. In addition to a blocking tab
55, which is integrally formed on the side facing the shank 22,
it has a window-like opening 56, from one of whose inner walls
a first retaining pin 57, which runs parallel to the
displacement direction 54 of the blocking pawl, for a
pretensioning spring 58 is integrally formed. A first arm 59 of
a second actuating element 60, which is held on the traveling
drive displaceably in the displacement direction 54 of the
blocking pawl,

protrudes into the window-like opening 56 of the blocking pawl
52. A cylindrical pin 61, which passes through inner walls,
which run at right angles to the displacement direction 54, of
the actuating element 60 and fixing lugs (opposite these walls)
of the traveling drive in the region of corresponding through-
holes, is used for holding this second actuating element 60 on
the traveling drive 15. In order to axially fix the inserted
pin, the pin has a tapered section 62, into which a sprung tab
63 of the actuating element 60 snaps. In order to dismantle the
actuating element 60, this tab 63 can be lifted out of the
tapered section 62 of the pin 61 by means of a screwdriver or a
comparably narrow tool and the pin can therefore be released
such that it can be pulled out.
A second retaining pin 64 for the pretensioning spring 58 is
integrally formed on the first arm 59 of the second actuating
element 60. A second arm 65 of the actuating element 60, under
the force of a resetting spring 66, which is supported on a
first supporting face 61 of one of the housing halves of the
traveling drive, bears against a second supporting face 68 of
this housing half. In order to guide the resetting spring 66,
one supporting face 67 and the actuating element 60 are
provided with in each case one retaining pin 69, 70. A first
cylinder lock 49 (illustrated schematically) is used for
controlling the actuating element 60. When this first cylinder
lock 49 is closed, a tab (not illustrated) acts in the
direction of the arrow 71 on the second arm 65 and displaces
the actuating element 60 and the blocking pawl 52, which is
coupled to the actuating element 60 via the pretensioning
spring 58, counter to the force of the resetting spring 66 from
an OFF position into an ON position in the direction of the
shank 22 of the actuating crank. When the shank 22 has been
inserted completely, i.e. when

the crank arm 27 has been lowered into its accommodating
pocket, the second blocking groove 53 of the shank 22 is
opposite the blocking tab 55 of the blocking pawl 52, with the
result that said blocking tab 55 can enter the blocking groove
53. When attempting to pull the crank arm 27 out of the
accommodating pocket 12, one side face of the blocking groove
53 comes to bear against a stop face 72 of the blocking tab 55
and therefore indicates to the operating personnel that
blocking of the traveling drive is taking place. In this case,
even a slight resistance is sufficient for indicating blocking
of the traveling drive. The second actuating element 60, in
contrast to the first actuating element 47 (blocking slide) of
the first blocking mechanism, can be displaced from its OFF
position into its ON position even when the crank arm 27 has
not or has not yet been completely lowered into the
accommodating pocket 12. With the shank 22 completely pulled
out, the blocking pawl 52 is likewise raised when the actuating
element 60 is raised and therefore protrudes into the movement
path of the shank 22. When the shank is pushed in, the end face
31 of the shank 22 slides over a sliding face 73 of the
blocking tab 55 of the blocking pawl and pushes the blocking
pawl 52, counter to the force of the pretensioning spring 58,
out of the movement path of the shank. Then, the blocking tab
55 slides along a flattened outer section 74 of the shank until
it latches into the blocking groove 53.
For the alternative actuation of the blocking pawl 52, the
second actuating element is coupled to a third actuating
element 75 in the form of a two-armed lever. For the coupling
process, the second actuating element 60 has a U-shaped cutout
76 at the free end of its first arm 59, a first arm 77 of the
two-armed lever engaging in said cutout 76. This two-armed
lever is capable of rotating about a stationary bearing screw
(not illustrated), which passes through a hole 78

of the third actuating element 75. The second lever arm 79 of
the third actuating element 75 can be actuated by means of a
pawl of the cylinder lock 50 in the direction of the arrow 80.
As shown in figure 4, the locking device 81 according to the
invention is fixed beneath the low-voltage circuit breaker 2 to
the bottom of the withdrawable rack 1.
As shown in figures 5 and 6, the locking device 81 has a
bearing plate 82, which, on one side, with a bent-back portion
(not visible in the figures) passes through the bottom 83 of
the withdrawable rack and which, on its opposite side, is fixed
to the bottom 83 of the withdrawable rack by means of a fixing
means 84 in the form of a screw. The bearing plate 82 has
supporting faces 86, 87, 88, which are bent back at right
angles to its bottom face 85 and are used for holding and
guiding further elements of the locking device.
For example, two hexagon bolts 89, 90 are mounted in rotatable
fashion on a first bent-back supporting face 86 and a second
bent-back supporting face 87, in each case one lever 91, 92
being held such that it is fixed against rotation on said
hexagon bolts 89, 90. The two levers 91, 92 are connected by
means of a rod assembly 93. A cable pull 94, which can be
actuated by means of a further cylinder lock 95, acts on one
lever 91. The rod assembly 93 is loaded by a second resetting
spring 96, which holds the two levers 91, 92 and therefore the
two bolts 89, 90 in a rest position when the cylinder lock 95
is unlocked.
While a means 97 for querying the position of the switch in the
form of two stop levers is held such that it is fixed against
rotation on one of the hexagon bolts 89, the other of the two
levers 92 is provided with a means 98 for blocking the
actuating

shaft 14 in the form of a cam disk. In this case, the cam disk
acts in the direction of the arrow 71 on the second arm 65 of
the second actuating element 60 (cf. figure 3) . The means 97
for querying the position of the switch and the means 98 for
blocking the actuating shaft 14 in an open position, which
corresponds to the unactuated OFF position of the second
actuating element 60, are located in the rest position of the
rod assembly 93.
A carriage 99, which is bent in the form of a U, is held
displaceably on the third bent-back supporting face 88. For
this purpose, the third supporting face 8 8 is provided with a
slot 100 (cf. figure 7), in which two bolts 101, 102, which are
connected to the carriage 99, are guided displaceably. In this
case, one of the two bolts 101 passes through the two lateral
guide faces 103, 104, which run parallel to the third
supporting face, of the carriage, which is bent in the form of
a U. A restraining means 105 in the form of a two-armed lever
is mounted pivotably on this bolt 101. In this case, one lever
arm 106 extends in the form of a bent-back portion which runs
parallel to the guide faces of the carriage bent in the form of
a U (cf. figure 8) in the direction of a rear wall 107 of the
withdrawable rack 1 (cf. figure 4). The second lever arm 108,
which extends in the direction of the open side 109
(cf. figure 4) of the withdrawable rack 1 in a plane which runs
substantially parallel to the bottom 110 of the carriage bent
in the form of a U has a bent-back portion 111, which points in
the direction of the bottom 110, at its free end
(cf. figure 8). Two bearing arms 112, 113 (cf. figure 8), which
run parallel to the guide faces of the carriage bent in the
form of a U and have a distance from one another such that the
outer width of the restraining means is matched to the inner
width of the carriage bent in the form of a U, are used for
pivotably mounting the restraining means 105 on the bolt

101. A third resetting spring 114 in the form of a helical
compression spring is supported between the bottom 110 of the
carriage 99 and the free end of the first lever arm 106. The
second 102 of the bolts acts as a first abutment for a fourth
resetting spring 115, which is in the form of a tension spring
and whose second abutment is formed by a pin 116. In this case,
the pin 116 protrudes away from the outwardly pointing, third
supporting face 88, mounted in front of the first bolt 101 in
the insertion direction 117. The guide face 103, which is
opposite this third supporting face 88, of the carriage 99 bent
in the form of a U has a tab 118, which protrudes into the
movement path of the low-voltage circuit breaker 2 and is used
for guiding the carriage 99 along with the switch when a
specific insertion position is reached.
A sensing means 119 in the form of a further two-armed lever is
mounted pivotably on the first bolt 101 between the carriage 99
and the restraining means 105. This sensing means 119 serves
the purpose of sensing the position of the actuating element 47
(of the blocking slide). Two guide slits 120, 121 are used for
axially positioning the sensing element 119, of which guide
slits a first 120 is provided in a rear bent-back portion 122
of the carriage 99 and the second 121 is provided in the second
lever arm 108 of the restraining means 105 and in the bent-back
portion 111 thereof. While the upwardly pointing edge of the
end of one lever arm 123 of the sensing means 119 is opposite
an actuating face 124 (cf. figure 9) of the first actuating
element 47 (blocking slide), a bow 126 of a lever mechanism 127
bears against the upwardly pointing edge of the free end of the
other lever arm 125. A first blocking means 128 in the form of
a blocking flap, which is bent in the form of a U, is held such
that it is fixed against rotation on the lever mechanism 127.
The blocking flap is held by a fifth resetting spring 129 in a
rest

position, in which it covers the two stop levers which form the
means for querying the position of the switch 97 and, as a
result, holds them in their open position (cf. figure 9).
The hexagon bolt 8 9 bears, in addition to the means 97 for
querying the position of the switch, a second blocking means
13 0 in the form of a frame-like flap, which bears against
retaining tabs 133, 134 of the two stop levers by means of an
edge 131 under the force of a second prestressing spring 132.
Figure 7 shows the locking device 81 in its unlocked release
position with the switch removed from the withdrawable rack. In
this case, the means 98 (cam disk) for blocking the actuating
shaft 14 is located in its OFF position, and the means 97 (stop
levers) for querying the position of the switch 97 is located
in its open position. Owing to the fact that there is no low-
voltage circuit breaker in the withdrawable rack, there is also
no first actuating element (blocking slide) acting on the one
lever arm 123 of the sensing means 119. In this case, the
forces of the fifth resetting spring 129, which acts on the
first blocking means 128 (blocking flap) , and of the third
resetting spring 114 (cf. figure 5), which acts on the
restraining means 105, are dimensioned such that the first
lever arm 123 of the sensing means 119 is pivoted downwards
into a first position corresponding to the blocking position of
the first actuating element 47 (blocking slide) and the first
blocking means 128 (blocking flap) is therefore pivoted upwards
such that the means 97 for querying the position of the switch
is released such that it can be moved into its blocking
position.
Figure 8 shows the locking device 81 in its locked locking
position with the switch removed

from the withdrawable rack. In contrast to the position as
illustrated in figure 7, in this case the means 97 for querying
the position of the switch (stop levers) is moved into its
blocking position by the actuation of the cylinder lock 95. In
this case, the second blocking means 130 (frame-like flap) is
released by the retaining tabs 133, 134 of the stop levers and
is therefore pivoted upwards such that a front edge 135
protrudes into the movement path 13 6 of the switch which points
in the insertion direction. Once a switch has been removed from
the withdrawable rack, renewed insertion of a switch is
therefore prevented when the locking device is locked. In this
locking position, the means 98 for blocking the actuating shaft
14 is located in a position in which the actuating element 60
is raised such that the blocking pawl 52 is located in its ON
position and the shank 22 is stopped in its axial direction.
As an alternative to the second blocking means, a third
blocking means, which is coupled to the means 97 for querying
the position of the switch, can be provided such that, when the
locking device is located in the locking position, removal of a
switch from the withdrawable rack is also prevented. For this
purpose, as shown in figure 12, a bent-back portion 138 is also
provided on the means 13 7 (in the form of a cam disk) for
blocking the actuating shaft, which bent-back portion 13 8 runs
at right angles to the movement path of the switch and, when
the switch is located in the isolating position in the
withdrawable rack and the locking device is located in its
locking position, is opposite a stop face 139 of the second
actuating element 60 and therefore blocks removal of the
switch. When the locking device is located in its locking
position, the same bent-back portion 138

is opposite a stop face 140 (cf. figure 3) of the housing 16 of
the traveling drive 15 of a switch 1 if an attempt is made to
insert the switch 1 into the withdrawable rack when the locking
device is located in its locking position and therefore
prevents the insertion.
Figure 9 shows the locking device 81 in its release position,
in which it cannot be locked since the low-voltage circuit
breaker is located in an intermediate position outside of the
preferred isolating position. In this intermediate position,
the first actuating element 47 is in its free position, i.e. in
its upwardly displaced position, since the preferred position,
namely the isolating position of the switch in the withdrawable
rack, has not yet been reached. The lever arm 106 of the
restraining means 105 is pivoted by the inserted switch and the
spring force of the third resetting spring 114 is blocked such
that the first blocking means 128 and the lever arm 125 are
held in their rest position under the force of the fifth
resetting spring 129, in which rest position the means 97 for
querying the position of the switch (stop levers) is stopped in
its open position.
A cam 136 is formed on the lever arm 106 of the restraining
means 105 such that the sensing means 119 and the first
actuating element 47 (blocking slide) are reliably associated
with one another irrespective of the position of the first
actuating element 47.
Figure 10 shows the locking device 81 with the switch located
in the isolating position in its unlocked release position, in
which, however, the means 97 for querying the position of the
switch is released such that it can be moved into its blocking
position. This release is brought about

by the first actuating element 47 (blocking slide) being moved
into its blocking position, i.e. by the blocking slide being
lowered. Such lowering of the blocking slide, as has already
been explained, is only possible, however, if the crank arm 27
has been recessed completely into the accommodating pocket 12
and therefore an actuation of the actuating crank 13 is
prevented (cf. figure 2).
Figure 11 shows the locking device 81 with the switch located
in the isolating position in its locking position, in which the
means 97 for querying the position of the switch is moved from
its open position (cf. figure 10) into its blocking position.
In its blocking position, the means 97 protrudes into the
movement path of the switch, with the result that a further
displacement of the switch beyond its isolating position in the
direction of the test and operating position is stopped.
In this case too, the blocking pawl 52 is caused to move into
its ON position owing to the rotation of the means 98 (cam
disk) for blocking the actuating shaft, with the result that
the shank 22 is stopped in its axial direction in this case,
too.
Figure 7

WE CLAIM :
1. A locking device (81) for an electrical switch (2), which is guided
displaceably in a withdrawable rack (1) by means of
an actuating shaft (14) and which, with the switch located in a
preferred position, in particular an isolating position, can be
moved from a release position, in which the switch is
displaceable in the withdrawable rack, into a locking position,
the locking device (81) in the locking position blocking a
displacement of the switch in the withdrawable rack in a
predetermined direction (117), and the actuating shaft (14) being capable
of being actuated via an actuating crank (13), wherein the actuating
crank(13) cannot be removed from the actuating shaft (14) being a part
of a traveling drive (15),
characterized in that the locking device can only be moved into
the locking position if the actuating crank (13) is blocked
against actuation.
2. The locking device as claimed in claim 1, wherein
a means (97) for querying the position of the switch
(2) is provided which, with the switch located in the preferred
position, can only be moved from an open position into a
blocking position if the actuating crank (13) is blocked
against actuation.

3. The locking device as claimed in claim 2, wherein
a means (98) for blocking the actuating shaft (14), which means
(98) is coupled to the means (97) for querying the position of
the switch, is provided in order to block the displacement of the
switch (2), an actuating element (47), which can be moved from a free
position into a blocking position, is provided in order to
block the actuation of the actuating crank (13),
a sensing means (119), which can be moved from a first
position, which corresponds to the blocking position of the
actuating element, into a second position, which corresponds to
the free position of the actuating element, is provided in
order to sense the position of the actuating element (47), and
a first blocking means (128), which is coupled to the sensing
means (119) by means of a coupling section, is provided in
order to block the means (97) for querying the position of the
switch, the first blocking means (128) only releasing the means (97)
for querying the position of the switch such that it can be
moved into its blocking position if the actuating element (47)
is located in its blocking position.
4. The locking device as claimed in claim 3, wherein the sensing means
(119) is mounted on a carriage (99) which can be displaced by means of
the switch (2).

5. The locking device as claimed in claims 3 or 4, wherein
a restraining means (105) is provided which, with the switch
(2) removed from the withdrawable rack (1) , keeps the sensing
means (119) in its first position, which corresponds to the
blocking position of the actuating element (47).
6. The locking device as claimed in one of claims 2 to 5, wherein
the means (97) for querying the position of the switch can be
stopped in its blocking position.
7. The locking device as claimed in claim 6, wherein a locking cylinder (95),
which is coupled to the means (97) for querying the position of the switch
by means of a cable pull (94), is used for stopping the means (97) for
querying the position of the switch in its blocking position.
8. The locking device as claimed in claim 6, wherein
a second blocking means (130) is provided which, with the means
(97) for querying the position of the switch stopped in its
blocking position and once the switch (2) has been removed from
the withdrawable rack (1), pivots into the movement path of the
switch which points in the direction of the preferred position.
9. The locking device as claimed in claim 6, wherein a third blocking means
(138) is provided which, when the means (97) for querying the position of
the switch is moved into its blocking position, pivots into the movement
path of the switch.

10. A withdrawable rack (1) with a locking device (81) for an electrical switch
(2) , which is guided displaceably in the withdrawable rack by means of
an actuating shaft (14), the locking device (81) is designed as claimed in
one of claims 1 to 9.
11. The withdrawable rack as claimed in claim 10, the locking device (81) has
a bearing plate (82) for arranging the locking device on the withdrawable
rack (1) beneath the switch (2).

ABSTRACT

TITLE A LOCKING DEVICE FOR AN ELECTRICAL SWITCH AND AN
WITHDRAWABLE LOCK WITH LOCKING DEVICE"
The invention relates to a locking device (81) for an electrical switch (2),
which is guided displaceably in a withdrawable rack (1) by means of
an actuating shaft (14) and which, with the switch located in a
preferred position, in particular an isolating position, can be
moved from a release position, in which the switch is
displaceable in the withdrawable rack, into a locking position,
the locking device (81) in the locking position blocking a
displacement of the switch in the withdrawable rack in a
predetermined direction (117), and the actuating shaft (14) being capable
of being actuated via an actuating crank (13), wherein the actuating
crank(13) cannot be removed from the actuating shaft (14) being a part
of a traveling drive (15), characterized in that the locking device can only
be moved into the locking position if the actuating crank (13) is blocked
against actuation.

A LOCKING DEVICE FOR AN ELECTRICAL SWITCH AND AN WITHDRAWABLE LOCK WITH LOCKING DEVICE

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