EP0386519A1 - Method and device for winding a predetermined length of yarn in layers on a bobbin - Google Patents

Abstract

A method and a device for winding predetermined lengths of yarn in layers on a bobbin by means of a winding element, especially for winding roving onto flyer bobbins (46) on a flyer, a relative axial to-and-fro movement occurring between the winding element (5, 44) and the bobbin during the winding operation, are characterised in that, to obtain a predetermined location of the yarn end or roving end on the bobbin (46), the wound-up length of yarn is continuously measured during the winding operation, and in that, when a predetermined wound-up length of yarn corresponding approximately to one of the last layers, but shorter than the predetermined length of yarn is reached, the relative axial position of the winding element (5, 44) and of the bobbin (46) or a parameter proportional to this is determined, and the device varying the relative position is so controlled that the length of yarn still remaining up to the predetermined length of yarn comes to an end at least essentially at the predetermined location as a result of controlled relative axial to-and-fro movements differing in amplitude from the previous amplitude. <IMAGE>

Description

The present invention relates to a method for winding predetermined lengths of yarn in layers on a spool with the aid of a winding element, in particular for winding roving onto roving bobbins on a flyer, with a relative, axial back and forth movement between the winding element and the bobbin during winding takes place.

In particular in the case of a flyer, but also in the case of other machines, for example rewinding machines or pre-twisting machines, attempts are made to always achieve wound bobbins with the same length of roving or yarn length wound on, so that during the subsequent processing of the roving or yarn on a textile machine having several workstations, for example a ring spinning machine, all bobbins are empty at the same time and can be replaced at the same time, which is particularly beneficial for automatic doffing. Providing the same wound yarn lengths on spools is not particularly problematic in most cases, since this length can be determined, for example, on a flyer by counting the revolutions of the delivery cylinder of the drafting system, i.e. of the organ that supplies the roving for the winding process.

It is problematic, however, to ensure at predetermined wound-up yarn lengths that the last winding always comes to lie at the same axial position of the bobbin, this point, which should preferably lie in the central region of the bobbin, always in the same winding or Winding direction is to be achieved. If this can be achieved, the spinning position on the spool is always already specified, which also makes the automatic handling of the spools on the subsequent processing machine considerably easier.

It is therefore an object of the present invention to provide a method and a device of the type mentioned at the outset, in which, even in the case of predetermined yarn lengths, the end of the yarn on the bobbin always at a predetermined point on the bobbin and preferably always in the same winding direction is achieved, which should in particular be directed upwards.

To achieve this object, the method according to the invention provides that, in order to reach a predetermined point on the end of the yarn or the roving end on the bobbin, the spooled yarn length is measured continuously during winding, that when reaching a predetermined wound yarn length, which corresponds approximately to one of the last layers , but is shorter than the predetermined yarn length, the relative, axial position of the winding element and the bobbin or a parameter proportional to this is determined, and the device which changes the relative position is controlled in such a way that the yarn length remaining up to the predetermined yarn length is controlled by targeted relative, axial back and forth movements differing in amplitude from the previous amplitude comes to an end at least essentially at the predetermined point.

In the method according to the invention, the procedure is therefore such that the amplitude of the axial reciprocating movements of the winding member relative to the spool in the final phase of the winding is controlled so that the last layer of turns and in most cases the last two layers of turns has or have an axial length that deviates from the axial length of the previous layers, but is selected so that the yarn end always at the same axial position or Height of the coil comes to rest.

It is also readily possible to control the device which changes the relative position of the winding element and the spool in such a way that the last part of the reciprocating movement always takes place in the same direction, preferably upwards. If you make sure that the last windings take place in the upward direction, the last windings form a step which prevents the yarn end from falling off and the bobbin is partially unwound.

Preferably, the procedure is such that the last part of the to-and-fro movement always has the same length, which ensures that the yarn or roving always moves in the same axial direction with respect to the bobbin during the following unwinding process , which also benefits the automatic handling of the coil.

This procedure can best be explained using a numerical example.

It is assumed that the predetermined length of yarn should be 5000 m, that the axial length of the fully wound bobbin is 50 cm, and that the last 100 m of the roving requires a space of 30 cm in one layer with the diameter of the fully wound bobbin.

When the reel is wound up, the wound length is measured continuously and when a wound length of 4900 m is reached, the exact axial position of the winding element relative to the reel is measured. Assuming that this axial position is 20 cm from the lower end of the bobbin, in the normal winding process of winding the last 100 m, the roving would end 50 cm from the lower end of the coil.

To prevent this, and to bring the roving end into the center of the bobbin, with the last turns in the upward direction and an axial length of 5 cm, the machine is controlled so that the winding in the upward direction over a further axial length of 12.5 cm is made that the winding direction then reverses and takes place over an axial length in the opposite direction of 12.5 cm, after which it reverses again and the last 5 cm to the center of the coil again in the upward direction be wound up.

It can be seen that by controlling the last two reversal points of the winding element with respect to the bobbin, it is always possible to bring the roving end to the desired axial position of the bobbin in the desired winding direction.

Since it is relatively difficult in practice to determine the axial length to be taken up by the end piece of the yarn to be wound up, so that even if the method according to the invention is used, the yarn end may lie in the region of the desired axial position of the bobbin, but may not be accurate At this point, the procedure according to the invention is preferably such that, after reaching the predetermined wound-up yarn length, a value from the subsequent winding operation is determined which represents the relative, axial movement of the winding element and the bobbin per meter of yarn or is proportional. This means that the control of the winding process and the determination of the last two reversal points is now carried out on the basis of the value determined in this way.

In the case of a flyer, the stated value can be determined from the roving length wound up during a certain time and the stroke movement of the bobbin taking place during this time. Knowing this value, you only need to multiply the remaining roving length by the factor determined in this way in order to calculate the axial length of the remaining yarn piece, whereby, starting from the first measuring point, the controller controls this lifting movement together with the lifting movement that has already taken place since the predetermined thread length must be taken into account for setting the reversal points. It would also be entirely possible within the meaning of the invention to determine the reversal points directly on the basis of the additional stroke length calculated in this way, provided that the control is then constructed in such a way that it starts from the current stroke height.

The stated value can also represent the relative, axial movement per winding length on the coil. Using the example of a flyer, this winding length can be determined from the roving length delivered by the delivery cylinder of the drafting system during a certain time and the number of turns resulting from the difference in speed of the flyer wings and the flyer spools during this time. By simultaneously determining the lifting movement of the flyer coils during the stated time, it is then possible to calculate the desired value of the relative axial movement per winding length on the coil.

The lifting movement of the flyer coils during the time mentioned can itself be determined, for example, from the speed of a motor producing the lifting movement by means of threaded spindles and the pitch of the threaded spindles, provided that the motor drives the spindles at the motor speed. Should a gearbox with gear ratio between motor and threaded spindle the gear ratio must be taken into account.

Even when determining the axial length for the end piece of the yarn during the winding operation, as explained above, due to the reversing movement of the winding element and the resulting increased diameter of the windings, a certain inaccuracy can occur. This inaccuracy can be corrected according to the invention in that when a large number of windings are wound on the last position originally assumed or when the relative back and forth movements change direction during the determination of the value mentioned, this is determined again in order to control the newly determined Value.

There are many options for the specific design of the control. For example, it is not necessary to specify the predetermined yarn length in meters, but one can simply specify a count of the counter counting the revolutions of the delivery cylinder. The axial lifting movement does not need to be expressed in centimeters either, but can be done by counting the revolutions of the lifting motor between the reversal points.

A preferred device for winding predetermined lengths of yarn in layers on a bobbin with the aid of a winding element, in particular according to one of the preceding claims, for example for winding roving onto flyer bobbins on a flyer, with a drive for generating a relative, axial back and forth movement between the winding element and the bobbin during winding, is characterized in that a measuring device for reaching a predetermined position of the yarn end or the roving end on the bobbin is provided, which continuously measures the wound-up yarn length during winding up, that a determining device is provided which, when reaching a predetermined wound-up yarn length, which corresponds approximately to one of the last layers, but is shorter than the predetermined yarn length, the relative axial position of the winding element and the bobbin or one of these proportional parameters determines that a control device is provided which, taking into account the remaining length of yarn up to the predetermined length of yarn, controls said drive to a reciprocating movement which differs in amplitude from the previous amplitude and which at least essentially come to an end at the specified position.

Based on the calculations to be performed, the determining device preferably includes a microprocessor that is programmed to perform the calculations based on the signals detected. Preferably, both the measuring device and the determining device and the control device are at least partially formed by a microprocessor that carries out the winding process. As a result, the microprocessor has the function of a control processor, which takes over the entire control of the winding process.

When the device according to the invention is designed in the form of a flyer, the measuring device is preferably characterized in that it measures the length of the roving wound by the rotations of the delivery cylinder and is preferably in the form of a tachometer generator. The latter would then be connected to the microprocessor, possibly with the interposition of a counter and / or a suitable interface. When using a microprocessor, the turning points are the back and forth movements from or over it can be predetermined, the back and forth movements of different amplitude being fixed by changing the reversal points during the last phase of the winding. For example, the microprocessor can change the position of adjustable limit switches that determine the reversal points, or, what is preferred, set or set these reversal points in a purely electronic manner.

The invention is explained in more detail below on the basis of an exemplary embodiment with reference to the drawing, which shows a work station of a flyer in a perspective, partially sectioned view.

As is well known, a flyer 2 nowadays usually has 100 to 200 such spinning positions. These spinning positions 4 are arranged in two rows on the same side of the flyer, the flyer wings 5 of one row being arranged offset from the flyer wings of the other row. The two rows of flyer wings are mounted in a common hollow beam 8 and are driven together by a drive arranged in this beam 8, as will be explained in more detail below. Such a flyer is described for example in DE-OS 25 43 842.

In the spinning station shown, a fuse 10 is pulled out of a can 12 and fed to a drafting device 16 via a deflection roller 14. The drafting system has two spaced-apart pairs 18 and 20 of drafting rollers, which are driven at different speeds in a manner known per se and form a draft zone in which the sliver 10 is stretched for the first time. Following the pair of rollers 20 there is at least one further pair of rollers 22, that runs faster than the previously switched pair of rollers 20 and thus forms a main warping area. As is usual with a drafting system, only the lower rollers of the roller pairs 18, 20, 22 are driven, the rollers being driven by all drafting systems by means of continuous shafts, while the upper rollers are pressed against and driven by the driven lower rollers so that the drafting systems perform the same drawing at all spinning positions and work at the same speed in each case. As shown in this exemplary embodiment, the fuse is often guided in the main draft zone by two endless belts 23, 25, which each wrap around a roller of the roller pair 20 and run over respective guides arranged in the region of the roller pair 22.

The lower rollers of the last roller pairs 22, for example driven by a continuous shaft, thus form the delivery cylinders for the respective work stations. The revolutions of this shaft, which at the same time correspond to the revolutions of the delivery cylinders 26, are measured via a tachometer generator 30 (only indicated schematically) and fed via line 32 to a microcomputer 34, which counts the impulses obtained and from this evaluates the roving length emitted by the pair of rollers 22. The stretched roving 36, which emerges from the pair of rollers 22, then comes directly into the neck 38 of one of the flyer wings 5 and through its right arm 42 in the drawing to the press finger 44, which is rotatably arranged about its longitudinal axis at the lower end of the arm and which by means of a Spring (not shown) is constantly pressed against the surface of the developing reel 46. The further arm part 48 of the flyer wing serves to balance the flyer wing. 10.1 indicates that a further fuse is also fed to the adjacent flyer wing in the outer row.

The hollow neck 38 of the flyer arm is supported in a bearing which is located within the hollow bar 8. The hollow bar 8 extends over the entire left side of the flyer and comprises the rotary drive for the flyer wings 5. For this purpose, a shaft 56 carrying gears 54 extends along the hollow bar 8, the gears 54 being attached to the sleeves 38 of the flyer wings Comb fixed gears 58. The motor producing the rotary movement 60 of the gear wheels 58 and therefore the rotary movement of the flyer wing 5 in the direction of arrow 56 is not shown in the drawing for the sake of illustration, but is merely indicated by a line 64 that the control of the corresponding motor that controls the entire spinning positions drives, takes place from the computer 34. Instead of a common drive motor, it is also possible to provide a separate motor for each spinning station.

The flyer spool partially wound in the drawing each has sleeves 66 which are driven by further gear wheels 68 via a further longitudinal shaft 70 equipped with gear wheels 72. The longitudinal shaft 70 as well as the gear wheels 68 and the gear wheels 72 are located within a further hollow beam 76. The longitudinal shaft extending along the hollow beam 76 is driven by a motor (not shown). This motor, not shown, is connected via line 74 to the computer 34 and controlled by it.

The hollow bar 76, which forms the so-called coil bank, is supported at both ends by threaded spindles 78, only one of which is shown schematically in the drawing. The threaded spindle 78, like the further threaded spindle, not shown, extends through a circumferential ball nut (not shown), which is mounted in a corresponding housing part 80 of the coil bank 76. The two spindles 78 are driven synchronously by a respective motor 82, these motors also being controlled from the microcomputer 34 via corresponding lines 84 (only one shown).

With 85 and 86 two limit switches are shown purely schematically, which come into contact, for example, with the upper and lower surfaces of the housing part 80 at the upper and lower ends of the normal stroke movement and are actuated by them to reverse the spindle movement. Although such limit switches would be technically possible, the function of the limit switches 85, 86 is in fact managed electronically from the microcomputer 34, which counts the number of revolutions of the lifting motors 82 and from this electronically calculates the desired reversal points. When the reversing points thus electronically calculated are reached, the spindle motors 82 are actuated again in the sense that the lifting movement reverses at these points. As indicated by the double arrow 88, the flyer spool and the spool bank 76 take part in this lifting movement, while the height of the flyer wings 40 remains constant during the winding operation.

Due to the difference in speed between the flyer wings 5 and the flyer spool 66, windings with the shape shown are formed on the sleeves 66, the conical parts at the upper and lower ends of the flyer spool being produced by electronic change in the reversal points of the stroke movement by means of the computer 34 and to form a stable structure lead for the fully wound flyer spool.

At the end of the winding process, the spool bank 76 is moved all the way down so that the full spool 46 is released from the flyer wings and then against the Tilted clockwise (to perform a doffing operation).

As previously explained, the computer 34 receives signals which correspond to the yarn length supplied by the delivery cylinder 26 and therefore also to the yarn length wound on the flyer spool. When the predetermined yarn length is reached, which can be entered into the microcomputer via the keyboard, the microcomputer 34 checks, based on the control signals for the drive motor 82, the current axial height of the pressing finger 44, which is the winding element, relative to the flyer spool 46. The computer determines from the subsequent winding operation 34 then from the signals of the tachometer generator 30 and from the control signals for the motor 82 a value which corresponds to the relative, axial movement of the winding element and the bobbin per meter of yarn. From this value and the remaining length of yarn to be wound up, which is necessary to achieve the predetermined length of yarn, the computer 34 then determines the required lifting movement and the reversal points which are necessary to bring the end of the yarn to the desired position.

Likewise, as previously explained, the computer 34 can determine the axial stroke movement per turn and the length of this turn, for which the different speeds of the shaft 54 and the shaft 70 are taken into account, based on the control signals sent to the respective motors via the lines 64 and 74 are delivered.

Claims (16)

1. A method for winding predetermined lengths of yarn in layers on a spool with the aid of a winding element, in particular for winding roving onto flyer bobbins on a flyer, with a relative, axial back and forth movement between the winding element and the bobbin taking place during winding, thereby characterized in that to reach a predetermined position of the yarn end or the roving end on the spool, the wound yarn length is measured continuously during winding, that when reaching a predetermined wound yarn length, which corresponds approximately to one of the last layers, but shorter than the predetermined yarn length the relative, axial position of the winding element and the spool or a parameter proportional to this is determined, and the device which changes the relative position is controlled in such a way that the yarn length still remaining up to the predetermined yarn length comes to an end at least essentially at the predetermined point through targeted relative, axial reciprocating movements which differ in amplitude from the previous amplitude. 2. The method according to claim 1, characterized in that the relative position of the winding element and the coil changing device is controlled such that the last part of the reciprocating movement always takes place in the same direction and preferably upwards. 3. The method according to claim 2, characterized in that the last part of the back and forth movement always has the same length. 4. The method according to any one of the preceding claims, characterized in that after reaching the predetermined wound yarn length, a value is determined from the subsequent winding operation, which represents the relative, axial movement of the winding element and the bobbin per meter of yarn or this is proportional. 5. The method according to claim 4, characterized in that in a flyer said value is determined from the length of roving wound during a certain time and the stroke movement of the bobbin taking place during this time. 6. The method according to claim 4, characterized in that said value represents the relative axial movement per winding length on the coil. 7. The method according to claim 6, characterized in that in the case of a flyer, the winding length is determined from the roving length supplied by the delivery cylinder of the drafting system during a certain time and the number of turns resulting from the differential speed of the flyer wings and the flyer spools during this time. 8. The method according to claim 7, characterized in that the lifting movement of the flyer coils is determined during the said time. 9. The method according to claim 8, characterized in that the lifting movement of the flyer coils is determined during the said time from the speed of a motor producing the lifting movement by threaded spindles and the pitch of the threaded spindles. 10. The method according to any one of the preceding claims 4 to 9, characterized in that when winding a plurality of turns on the last position originally assumed or in a change of direction of the relative back and forth movements during the determination of the said value this is determined again perform the control based on the newly determined value. 11. Device for winding predetermined lengths of yarn in layers on a spool (46) with the aid of a winding element (44), in particular according to one of the preceding claims, for example for winding roving onto flyer bobbins on a flyer, with a drive (78, 80, 82) for generating a relative, axial back and forth movement between the winding element (44) and the spool (46) during winding, characterized in that to achieve a predetermined Position of the yarn end or the roving end on the bobbin, a measuring device (30) is provided, which continuously measures the spooled yarn length during winding, that a determining device (34) is provided which, when reaching a predetermined wound yarn length, which is approximately one of the corresponds to the last layers, but is shorter than the predetermined yarn length, the relative axial position of the winding element (44) and the bobbin (46) or one of these proportional parameters determines that a control device is provided which takes into account the remaining yarn length up to the predetermined Yarn length controls the drive (78, 80, 82) mentioned to back and forth movements which differ in amplitude from the previous amplitude and which come to an end at least essentially at the predetermined position. 12. The apparatus according to claim 11, characterized in that at least the determining device includes a microprocessor (34). 13. The apparatus of claim 11 or 12, characterized in that both the measuring device (30) and the determining device and the control device are at least partially formed by a microprocessor (34) performing the winding process. 14. Device according to one of claims 11 to 13 in the form of a flyer with a plurality of workstations, each consisting of a drafting device for stretching the sliver (10, 10.1) fed to it, the delivery cylinder (26) of the drafting device (16), the drawn sliver (10, 10.1) forming the roving (36, 36.1) corresponds to the associated one Leaflet (5) feeds, with a reel bank (76) holding the flyer spools (46) and driven by the drive for a forward movement and with devices (68, 70, 72; 54, 56, 58) for driving the reels (66) and the flyer wing (5) for rotary movements of different speeds, characterized in that the measuring device (30) measures the length of the roving wound by the rotations of the delivery cylinder (26) and is preferably designed as a tachometer generator. 15. The apparatus of claim 13 and 14, characterized in that the tachometer generator (32) is connected to the microprocessor (34), optionally with the interposition of a counter. 16. The apparatus according to claim 15, characterized in that the reversal points of the back and forth movements from or via the microprocessor (34) can be predetermined and that during the last phase of the winding up the back and forth movements of different amplitude are determined by changing the reversal points .

Images