Claims
- 1. A splicing arrangement for carrying out a yarn splicing operation at a spinning point of a spinning machine of the type having a yarn delivery device for delivering yarn spun at the spinning point and a yarn package winding device for winding yarn from the spinning point onto a package, said splicing arrangement comprising:
- a splicing device for splicing new yarn delivered by the delivery device with old yarn withdrawn from the yarn package,
- an intermediate yarn storage device disposed upstream of the splicing device for storing new yarn delivered by the delivery device during splicing in the splicing device,
- and winding control apparatus for controlling the winding device so as to increase the speed of the winding of the yarn package as compared to its normal spinning operation speed during normal spinning operations to thereby withdraw yarn from the intermediate yarn storage device after splicing operations in the splicing device are completed, said winding device control apparatus including a stored yarn detection device for detecting the amount of intermediate stored yarn remaining in the storage device and means for effecting a reduction in the speed of the winding of the yarn package toward its normal spinning operation speed when the amount of yarn remaining in the storage device reaches a predetermined low level to thereby minimize tension peaks in the yarn being withdrawn from the storage device.
- 2. An arrangement according to claim 1, wherein the yarn detection device includes a detector for detecting the length of a yarn loop in the intermediate storage device.
- 3. An arrangement according to claim 2, wherein the intermediate storage device comprises a tube which is open on one side which can be applied to the path of the yarn and wherein a suction air source is connected to the tube to generate a suction pull which pulls the yarn into the tube in the form of a loop, and wherein the detector includes means for creating a light barrier in the tube.
- 4. An arrangement according to claim 1, wherein the yarn detection device includes a detector for detecting a point in time when a stored yarn loop in the intermediate storage device has a predetermined residual size during withdrawal of yarn from the intermediate storage device.
- 5. An arrangement according to claim 1, wherein an additional storage device is provided upstream of the intermediate storage device for receiving a predetermined yarn length during delivery of new yarn by the delivery device during splicing operations, and wherein the yarn detection device includes a detector for detecting the yarn at a point in time when it empties from the intermediate storage device.
- 6. An arrangement according to claim 1, wherein the yarn detection device includes a detector for detecting the extent of winding of yarn on the yarn package subsequent to completion of splicing operations.
- 7. An arrangement according to claim 1, wherein the yarn detection device includes a detector for detecting the yarn length withdrawn from the intermediate storage device after completion of splicing operations.
- 8. An arrangement according to claim 1, wherein the intermediate storage device comprises a tube which is open on one side which can be applied to the path of the yarn and wherein a suction air source is connected to the tube to generate a suction pull which pulls the yarn into the tube in the form of a loop.
- 9. An arrangement according to claim 1 wherein the yarn detection device includes a detector for detecting rotation of the yarn package after completion of the splicing operation.
- 10. An arrangement according to claim 1, wherein the winding control apparatus includes a computer control device for controlling the speed of the winding of the yarn package as a function of signals from the yarn detection device.
- 11. An arrangement according to claim 10, wherein the winding of the yarn package is controlled by a driven winding device during normal spinning operations.
- 12. An arrangement according to claim 11, wherein an auxiliary package driving device is provided for splicing operations, and wherein the speed of the winding of the yarn package is controlled by controlling the auxiliary package driving device.
- 13. An arrangement according to claim 12, wherein the auxiliary package driving device is provided on a mobile splicing unit which is selectively movable to respective spinning points of a multiple spinning point spinning machine.
- 14. An arrangement according to claim 13, wherein the intermediate storage device is carried by the mobile splicing unit.
- 15. An arrangement according to claim 14, wherein the yarn detection device includes a detector for detecting the length of a yarn loop in the intermediate storage device.
- 16. An arrangement according to claim 14, wherein the yarn detection device includes a detector for detecting a point in time when a stored yarn loop in the intermediate storage device has a predetermined residual size during withdrawal of yarn from the intermediate storage device.
- 17. An arrangement according to claim 10, wherein the computer control device and intermediate storage device are carried on a mobile splicing unit which is selectively movable to respective spinning points of a multiple spinning point spinning machine.
- 18. An arrangement according to claim 17, wherein the yarn detection device includes a detector for detecting the length of a yarn loop in the intermediate storage device.
- 19. An arrangement according to claim 17, wherein the yarn detection device includes a detector for detecting a point in time when a stored yarn loop in the intermediate storage device has a predetermined residual size during withdrawal of yarn from the intermediate storage device.
- 20. An arrangement according to claim 17, wherein an additional storage device is provided upstream of the intermediate storage device for receiving a predetermined yarn length during delivery of new yarn by the delivery device during splicing operations, and wherein the yarn detection device includes a detector for detecting the yarn at a point in time when it empties from the intermediate storage device.
- 21. An arrangement according to claim 17, wherein the yarn detection device includes a detector for detecting the extent of winding of yarn on the yarn package subsequent to completion of splicing operations.
- 22. An arrangement according to claim 17, wherein the yarn detection device includes a detector for detecting the yarn length withdrawn from the intermediate storage device after completion of splicing operations.
- 23. An arrangement according to claim 17, wherein the intermediate storage device comprises a tube which is open on one side which can be applied to the path of the yarn and wherein a suction air source is connected to the tube to generate a suction pull which pulls the yarn into the tube in the form of a loop.
- 24. An arrangement according to claim 1, wherein said spinning point includes spinning means for spinning a yarn having only a relatively low resistance to tearing and formed by prestrengthening with pneumatic false twist spinning.
- 25. An arrangement according to claim 10, wherein said spinning point includes spinning means for spinning a yarn having only a relatively low resistance to tearing and formed by prestrengthening with pneumatic false twist spinning.
Priority Claims (2)
| Number |
Date |
Country |
Kind |
| 3829151 |
Aug 1988 |
DEX |
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| 3905940 |
Feb 1989 |
DEX |
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BACKGROUND AND SUMMARY OF THE INVENTION
This application is a Continuation-in-Part application of Application Ser. No. 07/398,429, filed Aug. 25, 1989, now U.S. Pat. No. 4,972,668.
The invention relates to an arrangement for carrying out a yarn piecing operation at a spinning unit or point of a spinning machine. The yarn piecing apparatus includes devices for taking over an end piece of an old yarn wound onto a package, devices for taking over a new yarn produced by the spinning point, devices for connecting the old and the new yarn, devices for the intermediate storage of the yarn length of the new yarn produced during the connecting, and devices for winding the connected yarn onto a spool package which contain a package drive. The package drive is controlled by a controlling device which is held at a speed which is increased in comparison to the operating speed until the intermediately stored yarn length is used up,.
An arrangement of this type is the object of the above identified U.S. application (Corresponding also to German Patent Application P 38 29 151.7). It is endeavored, after establishing the yarn connection, to evacuate the intermediate storage device as fast as possible so that the concerned spinning point may resume its operative condition as soon as possible. This is particularly useful in the case of a movable arrangement which is assigned to a plurality of spinning points so that the arrangement will be ready again as soon as possible for a piecing operation at another spinning point. In addition, it must be ensured that, when the intermediate storage device is evacuated, the yarn is not stressed excessively. Particularly in the case of a yarn with a low resistance to tearing, this stress may otherwise result in a yarn breakage. A particularly critical point in time is at the end of the using-up of the intermediately stored yarn length, because at the latest at that point the withdrawing can no longer take place at a high wind-up speed because otherwise a tension peak may occur which results in the destruction of the yarn.
An object of the present invention is to develop an arrangement of the initially mentioned type such that, on the one hand, a fast evacuation of the intermediate storage device is possible and, on the other hand, tension peaks are largely avoided.
This object is achieved according to preferred embodiments of the invention in that the control device is connected to a device for determining the expected point in time of the using-up of the intermediately stored yarn length and, as a function of that, controls the reduction of the speed of the devices for the winding-up.
By means of this development, the circumstance is taken into account that the wind-up operation, during the evacuation of the intermediate storage device, may take p lace at very different conditions and at very different speeds. The packages may have very different diameters and/or also differences in the density of the winding and thus in the hardness of the surface so that very different acceleration behaviors occur, by which the packages are accelerated up to the increased wind-up speed. Here it must also be observed that the yarn must by no means be wound onto the package too loosely because this ma result in difficulties during the further processing. These different conditions which lead to a different slippage between a driving element and a package, are taken into account by monitoring the winding-up and determining the point in time at which the using-up of the intermediately stored yarn length is expected. Correspondingly, the speed of the package is controlled so that tension peaks are avoided. It is therefore possible to precisely control the speeds at the start as well as at the end of the wind-up up at increased speed, so that smooth transitions are obtained.
In a further development of the invention, it is provided that that the control device contains a computer determining the time period that remains for the using-up, a signal generating device being assigned to this computer which generates a signal that is representative of the yarn length still to be wound up. The drive will then be controlled as a function of the actual circumstances so that all sources of error are compensated which occur as a result of different slippage conditions between the driving element and the package.
In a first embodiment of the invention, it is provided that the signal generating device contains devices for detecting the length of a yarn loop received in the intermediate storage device. By means of a continuous monitoring of the intermediately stored yarn length, the evacuation of the intermediate storage device can therefore be controlled very precisely.
In another embodiment of the invention, it is provided that the signal generating device contains devices connected to the intermediate storage device for detecting the point in time at which the stored yarn loop during the evacuation has a given residual size. The point in time of the reaching of this residual size of a yarn loop is a sufficiently accurate signal from which the expected end of the using-up of the intermediately stored yarn length may be determined.
In a further embodiment of the invention, it is provided that an additional storage device, which receives a defined yarn length, is connected in front of the intermediate storage device, and in that the signal generating device contains devices for detecting the yarn at the point in time of leaving the intermediate storage device. In these embodiments, it is also not important which length of the yarn was in fact stored in the intermediate storage device.
In a further embodiment of the invention, it is provided that the signal generating device contains devices for detecting the course of the wind-up speed after the connecting of the old and the new yarn. This embodiment is based on the fact that it is certain with sufficient accuracy which length of yarn is stored in the intermediate storage device so that, on the basis of the course of the wind-up speed, the point in time of the using-up of the yarn length can be determined. In another embodiment, it is provided under the same conditions that the signal generating device contains devices for detecting the yarn length withdrawn from the intermediate storage device after the connecting. It is also a prerequisite here that the yarn length to be withdrawn is known with sufficient accuracy. Since this yarn length is a function of the delivery speed of the spinning point at which the yarn piecing is carried out, this is known with sufficient accuracy.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
US Referenced Citations (9)
Continuation in Parts (1)
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Number |
Date |
Country |
| Parent |
398429 |
Aug 1989 |
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Patent Grant
5079908
