Title of Invention

SPINNING FRAME WITH SEPARATE DRIVE UNITS FOR THE DRAWING UNIT CYLINDERS

Abstract

(57) Abstract: A spinning frame with a drawing unit whose cylinders are driven separately by a number of synchronous motors onto which via allocated frequency adjusters alternating currents of different frequencies, adjusted to a required ratio of drawing with respect to each other, being fed with adjustable frequency at a respective frequency control inlet of the frequency adjuster, a spindle drive being also fed with alternating current of adjustable frequency via a further frequency adjuster and' a confrol means to serve to determine the alternating current frequency is to be specified, which in particular ensures a reliable mutual adjustment of the rotational speeds of the drawing unit cylinders and in which deviations from the required ratios of drawing can be avoided reliably. For this the control means is to be furnished with an analogous outlet which emits an analogous signal to a frequency control analogue inlet of a first frequency adjuster and to a voltage- controlled main frequency generating circuit, which generates a main frequency signal being determined through the voltage of the analogue signal to be emitted to the inlets of respective frequency dividers, which provide varying sub-frequencies at the frequency control inlets of the remaining frequency adjusters in order to obtain the required amount of drawing. PRICE: THIRTY RUPEES

Full Text

The invention relates to a spinning frame according to the preamble of claim 1. A general problem in spinning frames consists of the fact that for the achievement of the-required ratios of drawing for a specified yarn, the rotating speeds of the single drawing cylinders have to be adjusted exactly in relation to each other, as well as to the rotation of the spindles. In particular when starting the frame from a standstill and when slowing the frame down to a standstill drawing'errors can occur/ which can even result in yarn breaks. The conventional gear wheel drives which served the purpose of keeping the rotation speeds of the single drawing unit cylinders at a fixed relation to each other, have recently been replaced by arrangements in which for each axis one or more independently running electro-motors are provided. Such an arrangement is for instance known from the patent specification EP-Bl-0 349 831, according to which the cylinders of a drawing unit are driven by one drive each. From the patent application DE 39 32 614 Al furthermore a spinning frame is known whose cylindrical rollers are directly coupled to drive shafts of separately controlled motors. The control means is provided with a memory device in which the rotation speeds of the single motors are stored in advance in order to tra-nsmit corresponding signals to the respective motors that are in operation. Such an arrangeinent, however, is very expensive because of the great number of single motors present in a spinning frame, that have to be controlled, in particular if the control means is to work so fast, that the spinning frame for instance could be started within a short time of a few seconds from a standstill to for instance 20.000 revolutions/minute. It is the task of the present invention to create a new type of spinning frame of the above mentioned design, which in particular provides a reliable adjustment of the rotation speeds of the drawing unit cylinders in relation to each other and in which deviations from the required rations of drawing can be avoided in a reliable way. The task of the present invention is solved by a spinning frame with the characteristic features of the independent claim 1. The idea of the invention is thus to be seen in the feature, that from the control means only one control signal is emitted from which on one hand the frequency of a first frequency adjuster is derived and froir. which on the other hand, by means of only cheap small-signal-elements, the further frequency signals, being required for the control of the drawing 'unir meters, are derived. The use of reluctance motors to drive the roller cylinders is particularly preferable, because, with the corresponding specification, they run over a large frequency range without hunting and without further measures, right from starting of the frame, synchronously from zero. While in spinning frames with short cylindrical rollers one motor is sufficient, in spinning frames with particularly long cylindrical rollers it is preferable to provide a synchronous motor on both sides of the cylindrical rollers, whereby both synchronous motors are supplied v.'ith power from the same frequency adjuster, since this way the undesirable torsion of the cylindrical rollers is being reduced to a minimum. In ^jpinning frames with pair-type structured drawing unit, in which for instance each two front, two intermediate, and two back cylinders are provided, it is possible that with cylindrical rollers being driven on both sides, one single frequency adjuster can drive up to four motors, which distinctly reduces the structural expenditures. Additionally in spinning frames with particularly long cylindrical rollers the rollers can also - preferably in the middle - be divided and be driven by a motor each at an end. The frequency adjusters can either be frequency converters being supplied with alternating current, for instance 380 V current or they can be inverted rectifiers supplied with direct current. The voltage controlled main frequency generation circuit comprises preferably an analogue-to-digital converter and a digital multiplier in order to generate from the analogous signal which is emitted by the control means, a dii^itcJ. Tiiaiii frequency signal. Said digital main frequency sianal ca-T h-e down-divided, at high precision and with minor effort:, ty a digital-effective frequency dividers, in order to provide sub-frequency signals for the digital control of the frequency adjusters. Thus the ratio-accuracy of gear wheel drives can easily be reached. If the requirements on the ratio-accuracy are not as high, then alternatively an anaI6gous signal transmission could also be applied. The ratio of division, which is Set on the frequency dividers, and thereby the desired ratios of drawing, can selectively be generated via a code switch and/or via a rotio of division-outlet of the control means, for instance via a serial interface. In a preferred embodiment the control means consists of a memory-programmable control means which emits a time-varied analogous signal for following through a predetermined spinning programme. Preferably the analogous signal from the control means is connected to the voltage controlled main frequency circuit via a loading circuit, in order to first build a balloon while .starting up the spindles and while the drawing unit is not switched on yet. The loading circuit, for instance formed as an RC-link:, in this case can thus in a simple way generate a delayed start-up of the drawing unit cylinders in relation to Che spindle rotation. A switch provided ahead of the load circuit, for instance a transistor being driven by the control means, can moreover switch on the load circuit after a delay. If necessary, a further switch could be used in order to separate the condensator of the RC-link in a load circuit formed as an RC-link, from the Load circuit, and preferably be discharged for the next delayed run-up of the spinning frame. Thus on the one hand sufficient time can be provided for the run-up of the spindles, that means for the formation of the balloon, before the drawing unit starts. On the other hand it is avoided, that, while the drawing unit is in operation, a change of the spindle speed is followed only slowly. The preferred embodiments thus present an extremely inexpensive electronic coupling, thereby avoiding a mechanical coupling which is much more expensive, in particular when applying reluctance motors in the drawing unit drive. With said arrangement a particularly high degree of ^^ adjustability of the speed of the single drive motors can be ■Si achieved during normal spinning operations. O m ^ The control means can in a preferred way be applied for a & drawing unit being disclosed and claimed in an application being filed at the same time (our reference R 3360), whose substance of disclosure, by way of references, is also made the object of the present invention. CD Accordingly, the present invention provides spinning frame, a ring spinning frame in particular, with a drawing unit whose cylinders are separately driven by synchronous motors, onto which motors alternating currents with varying and adjustable currents are being applied via frequency adjuster at respective frequency control terminals, on said frequency adjusters, whereby the frequency is being determined by the respective rotation required for the specified amount of drawing, a spindle drive being also supplied with alternating current of adjustable frequency via a further frequency adjuster and a control means serving the determination of the alternating current frequencies, characterized in that the confrol means is provided with an outlet which issues an analogue voltage signal to a frequency control inlet of a frequency adjuster and to a voltage controlled main frequency generating circuit, which generates a main frequency signal, determined by the signal, to be issued at the inlets of the respective frequency divider, which frimish, down-divided, varying sub-frequencies to the frequency control inlets of the remaining frequency adjusters, in order to achieve the necessary drawing effect. In the following the invention will be described merely for example in relation to the drawing, wherein shows : Fig. 1 a schematical view of a spinning frame according to the S invention fig. 2 a speed-time diagram, which illustrates the starting characteristic of a preferred embodiment of the spinning frame according to the invention by the example of the speed of the spindle and pre-cylinder. fig. 3 various alternatives of the power-flow in a spinning frame according to the invention. According to figure 1 a spinning frame 10 comprises a spindle drive 20, preferably with an asynchronous motor, which receives alternating current from a frequency adjuster 18. The frequency of the alternating current is controlled via control signals from a control outlet 22a of a control nieans 22 with programmable memory, said frequency being connecred tc a frequency control analogue input 18a of the frequency adjuster. At this point provision can be made, T:h=- a voltage between 0 and 10 volt on the frequency control j^r.-et 18a of the frequency adjuster 18 corresponds with a rotation of between 0 and 25.000 revolutions/minute. Yarn [not shown) is lead to the spindles from drawing units comprising a front or supply cylinder 14a, an intermediate cylinder I'^b and a back or inlet cylinder 14c, which, in the present spinning frame 10 are being provided as pairs and which are driven separately by synchronous motors, preferably reluctance motors 12a, 12b, 12c, and which, in connection with the use of very long drawing cylinders as is shown are arranged in pairs on both sides of each cylinder, so that in a three-cyiindrical drawing unit at maximum tiiree groups of four synchronous motors, as for instance 12ai, 12ar, i2a.i, 12a^ with preferably identical specification, are arranged. For the achievement of a predetermined ratio of drawing each group of motors, comprising four motors 12a, 12b, 12c, receive alternating current of a predetermined frequency from their own frequency adjusters 16a, 16b, 16c at a frequency control inlet 16a:, 16b:, 16c of the respective frequency adjuster, in a way to be described in more detail below. The analogous signal being generated by a memory-prograraraable control means 22 at its outlet 22a, is led furthermore preferably via a switch 40a being normally closed during operation and a load circuit 32, which load circuit is formed for instance by an RC-linJc with the use of a switch 40b for selective charging or discharging a condensator, to a inaii;i frequency generating circuit 24, which in a preferred embodiment comprises an analogue-to-digital converter 24a and a digital multiplier 24a conhected to it in succession. For the supply of the drawing unit motors 12a, 12b, 12c, the output signal from che main frequency generalior. circuit is connected via the lines 42a-42d and the frequency dividers 26a, 26b, 26c ccr.nected to it, to the frequency ccntrri inlets 163:, 16b:, 16c: cf the frequency adjusters ic-a;, I'z., l€c. The frequency dividers 26a/ 26b, 26c each are furnished, with a second inlet, which is connected via the respective lines 44a, 44b, 44c with an input switc-h 30, as for instance a code switch, for determininq the ratio of division achieved in the frequency dividers. The single ratios of division can also be determined selectively by signals being emitted on a suitable outlet of the nvemory-programmable control means 22. The power inlet of each frequency adjuster can be connected to an intermediate network 28 which is common to all frequency adjusters of the drawing unit and the frequency adjuster of trie spindle. Furthermore a ring frame motor 34 is provided on the spinning frame, said ring frame motor is being supplied with alternating current power of controllable freguency from a frequency adjuster 36 also being supplied with power from an intermediate network 29, which controllable frequency is being supplied to a frequency control inlet 36ai of the frequency divider 36 through a control signal via a line 38 of a second control inlet 22b of the memory-programmable control means 22. In a preferred embodiment a respective release control connection 36a; is provided on the frequency adjusters 16a, 16b, 15c of the drawing unit, on the frequency adjuster 36 of the ring rail respectively, which is connected with the control means 22 via a release line 46a-'36d for selective release. Possible configurations for the intermediate network are shown in figure 3. According to figure 3a the frequency adjusters 18, 16 and 34 are furnished as inverted rectifiers, which are supplied with a constant voltage of for instance 540 V from a rectifier 52, which rectifier is common for all frequency adjusters and which is being supplied with three-phase current 3f 3SC V. According to figure 5b the frequency adjusters 18, 16 and 34 are all furnished as frequency converters, which ar-i supplied with power by a common 380 V threephase current intermediate network 28. According to figure 3c only the frequency adjuster 18 is furnished as a frequency converter being supplied with 380 V threephase current, from whose 540 V intermediate circuit the intermediate network 28 is being fed with power for the further frequency adjusters 16 and 34 being furnished as inverted rectifiers. The frequency adjuster thus can be inverted rectifier or frequency converters, depending on whether the common intermediate network 28 is being supplied with direct current power or otherwise vjith polyphase alternating currenr powet. Furthermore the frequency adj'jster 18 can be a frequency converter, with the inverted rectifiers 16a, 16b, 16c connected to its direct current intermediate circuit. The spinning frame accordiaq—to the present invention operates as follows: When starting the spinning frame at first the low level signal ::ircuits such as the control means 22, the main frequency g'=nei:atoi 24, the frequency dividers 2b etc. are switched on, and from the intermediate network 28 the necessary electrical power to operate the motors is provided to the frequency adjusters. Then either via the key board 30 or the control means 22 and the line '54 or via the separate code switches 30', the required ratios of division for a certain amount of drawing are set on the frequency dividers 26a, 26b, 26c of the drawing units. If necessary, the switch 40a is opened previously and the switch 40b is turned into the loading position. Then, if necessary, via the lines 46 one release signal each is fed to the release inlets 16a;, 16b:, 16c; of the frequency adjuster 16 of the drawing unit as well as to the release inlet 36a; of the frequency adjuster 36. Now ::he spinning frame is set tr a desired drawing ratio of drawing. After this preparation phase, from the analogue outlet 22b of the control means, via the line 38 an analogue signal for "the control of the ring frame drive is emitted as required to the frequency control analogue inlet 36a2 of the frequency adjuster 36 and at the analogue outlet 22a of the control means 22 an analogous signal within the range between 0 and 10 Volt is transmitted to the frequency control analogue inlet 18a of the frequency adjuster 18, whereafter said frequency adjuster issues an alternating current to the spindle drive 20 with a frequency which for instance corresponds with a relation of bet'/-eeu 0 and 25.000 revolutions per minute. As soon as a predetermined time interval has passed, the switch 40a is closed, so that the analogue signal, from the analogue ^gnal 22a of the control means 22, is applied further via the load circuit 32 to the main frequency generator 24, at whose inlet the voltage now increases according to the load rate of the condensator provided in the RC-link 32, as is shown in figure 2. In the illustrated exemplified embodiment, said increasing analogue signal is transformed into a digital value by the analogue-to-digital converter 2^a, said digital value being fed to the digital multiplier 24b. The digitally multiplied value is applied to the frequency dividers 26a, 26b, 26c of the drawing unit as a main frequency signal via the lines 42b, 42c and 42d branching of the line 42a. In the frequency dividers 26 the applied main frequency signal is down-divided to sub-frequency signals, that means according to Che independently adjustable ratios of division which were transmitted to the respective frequency dividers 26 via the lines 44 from the key board, the code switch 30' respectively cr from the ccntrox means 22. These suc-tre-q^jiency =i'Tn.£ls in turn are digital values, which represent a desixed frequency adjuster outlet frequency. The sub-freq-Lier.cy sirnals are fed into the digital frequency control inlets iz=. , Itr and 16c: of the frequency adjusters 16a, 16b and 16c of the drawing unit. At response to the sub-frequency signals the frequency adjusters 16a, 16b and 16c Chus generate an alternating current of a frequency, which causes the motors 12 to rotate at the required speed for the desired ratio of drawing. As soon as the drawing unit has been started smoothly through the slow increase of the output voltage of the load circuit, the switch 40b is opened. Thereafter the drawing unit follows exactly (gear wheel-conform) to each change of the spindle frequency if for instance the signal given to the frequency adjuster 18 of the spir.dle drive changes at the auaJ.ogous outlet 22a of the control means 22 according to □ predetermined programme. The provision of a high-frequency main frequency signal which is down-divided, thus allows an especially precise adjustment ^ of the rotational speeds achieved on the individual motors. The speed of the drawing unit cylinders and of the ring frame thus follow the spindle drive rotation frequency predetermined via the control means 22, without the need of an extra tachogenerator or any other expensive device on the spindle drive. With a respective layout of the RC-link a delayed start¬up of the individual cylinder rollers with respect to the spindle motor can be achieved. The effect of delay can be increased in that the switch 40 is only closed after the spindles have already been started. In figure 2 said starting characteristic of a spinning frame according to the invention is shown with the example of the rotational speeds n of the spindle and pre-cylinder for the case that the switch 40 is being closed after a time tl in succession of start-up of the spindle drive at the zero point. The control means 22 c=r: t^ air=_vged tc enit an analogue signal which timely changes acc;riir_; 'o a pre-determined spinning programme. If desired, the rat^o cf drawing can be corrected ot changed during the spinning process either via the key board 30 or the control means 22. Thus it is possible to very quickly change the ratios of drawing. Due to the high-frequency motor frequency signal "the ratio of drawing can be set very precisely through the frequency dividers 26. If reluctance motors are used as synchronous motors, it is furthermore possible, to fixedly connect said motors directly with the cylinder rollers without the necessity of a coupling in-between, since the reluctance motors draw themselves into synchronisation as described above. A preferred arrangorr^ent thereto is described in the application being filed at the same time under the heading „gear for a ring spinning frame" (our reference; P 3360). Due to the fact that the ring frame obtains its frequency control si^a^al from a second analogous outlet'22b of the '~ control means 22, the ring rail can be moved independently of the drawing unit cylinders and the spindle drive, in particular also then v/hen the other drives are at rest. WE CLAIM : 1. Spinning frame, a ring spinning frame in particular, with a drawing unit whose cylinders (14ai, 14a2, Mb,, 14b2, 14ci, 14c2) are separately driven by synchronous motors (12ai, 12a2, 12a3, 12a4, 12b,, 12b2, 12b3, 12b4, 12ci, 12c2, 12c3, I2C4), onto which motors alternating currents with varying and adjustable currents are being applied via frequency adjuster (16a, 16b, 16c) at respective frequency control terminals, on said frequency adjusters, whereby the frequency is being determined by the respective rotation required for the specified amount of drawing, a spindle drive (20) being also supplied with alternating current of adjustable frequency via a further frequency adjuster (18) and a control means (22) serving the determination of the alternating current frequencies, characterized in that the control means is provided with an outlet (22a) which issues an analogue voltage signal to a frequency control inlet (18a) of a frequency adjuster (18) and to a voltage controlled main frequency generating circuit (24), which generates a main frequency signal, determined by the signal, to be issued at the inlets of the respective frequency divider (26a, 26b, 26c), which furnish, down-divided, varying sub-frequencies to the frequency control inlets (16ai, 16b|, 16ci) of the remaining frequency adjusters (16a, 16b, 16c), in order to achieve the necessary drawing effect. 2. Spinning frame according to claim 1, wherein the synchronous motors that drive the drawing unit cylinders are reluctance motors or permanent excited induced synchronous motors. '-^,. i^ .■ 3. Spinning frame according to one of the preceding claims wherein the frequency adjusters (18, 16a, 16b, 16c) are provided with a power inlet being fed from one of die frequency adjusters (18). 4. Spinning frame according to one of the preceding claims wherein each drawing unit cylinder is frimished with two synchronous motors, one at each of the opposite ends of the drawing unit cylinders, both of which are supplied by the same frequency adjuster, with alternating current of same frequency. 5. Spinning frame according to claim 4, wherein the drawing unit cylinders are divided, divided in the middle in particular and that each sub-cylinder is driven separately. 6. Spinning frame according to one of the preceding claims wherein the frequency adjusters are fiamished as inverted rectifiers being supplied with direct-current power at their inlet side or as frequency converters being supplied with alternating current power at their inlet side. 7. Spinning frame according to one of the preceding claims characterized in that the voltage-controlled main frequency generating circuit (24) ^ comprises an analogue-to-digital converter (24a) and a digital frequency multiplier (24b), which generate a digital main frequency signal, which is digitally down-divided by the frequency dividers (26a, 26b, 26c) and that the frequency control inlets of the frequency adjusters are designed to receive digitally predetermined control signals. 8. Spinning frame according to one of the preceding claims, wherein for the adjustment of the ratio of divisions of the frequency dividers (26a, 26b, 26c) coding switches (30) are provided. 9. Spinning frame according to one of the preceding claims, wherein the control means (22) is a memory-programmable control means. 10. Spinning frame according to one of the preceding claims wherein the analogous signals emitted at the analogous outlet (22a) of the control means (22) are transmitted to the voltage-controlled main frequency generating circuit (24) via a load circuit (32). 11. Spinning frame according to claim 10, wherein a switch is provided ahead of the load circuit. 12. Spinning frame according to one of the preceding claims wherein for the ring rail a separate motor (34) and frequency adjuster (36) are provided. 13. Spinning frame according to one of the preceding claims, wherein the control means (22) is configured to prepare release signals for the frequency adjusters (16a, 16b, 16c, 36) in particular the frequency adjusters of the drawing unit (16a, I6b, 16c). 14. Spinning frame according to one of the preceding claims wherein the frequency adjuster (18) being furnished with a frequency control analogue inlet (18a) is supplying power to the spindle drive (20). 15. Spinning frame substantially as herein described with reference to the accompanying drawings.

Documents:

1090-mas-1996 abstract.jpg

1090-mas-1996 abstract.pdf

1090-mas-1996 claims.pdf

1090-mas-1996 correspondence-others.pdf

1090-mas-1996 correspondence-po.pdf

1090-mas-1996 description (complete).pdf

1090-mas-1996 drawings.pdf

1090-mas-1996 form-2.pdf

1090-mas-1996 form-26.pdf

1090-mas-1996 form-4.pdf

1090-mas-1996 form-6.pdf

1090-mas-1996 petition.pdf