GB2255986A

GB2255986A - Yarn feeding device.

Info

Publication number: GB2255986A
Application number: GB9210575A
Authority: GB
Inventors: Paul Neher; Jurgen Hufner
Original assignee: Sipra Patententwicklungs und Beteiligungs GmbH
Current assignee: Sipra Patententwicklungs und Beteiligungs GmbH
Priority date: 1991-05-21
Filing date: 1992-05-18
Publication date: 1992-11-25
Anticipated expiration: 2012-05-18
Also published as: GB2255986B; JP3357955B2; DE4116497A1; JPH05178534A; ITMI921193A1; TW198738B; SE9201343D0; IT1255740B; ITMI921193A0; DE4116497B4; SE508146C2; SE9201343L; GB9210575D0

Description

- c)) "),.) X Strand FeedinR Device This invention relates to a strand

feeding device of the Idnd specified in the pre-characterizing part of claim 1.

In devices using or consuming strands, e.g. textile machines, especially knitting machines, it is frequently desired to feed thread, strand, strip or wire type material or the like, referred to briefly below as strands, selectively continuously or intermittently (DETS 2 939 803, USTS 3 418 831, USTS 4 027 405). Strand feed devices used primarily for this are socalled belt feeders, which have a rotatable strand drum with a first peripheral section in contact with a feed and transport conveyor formed as a belt and a second peripheral section free from the feed and transport conveyor. Accordingly, if the strand is between the first peripheral section and the feed belt, it is necessarily and continuously fed with a speed corresponding to the peripheral velocity of the strand drum or the transport velocity of the feed band (positive strand feed). If however the strand is arranged on the second peripheral section, it is only fed when a pull is exerted thereon by the device processing the strand (intermittent strand feed). To select the desired End of feed, a strand guide element adjustable manually or automatically, especially under pattern control, is associated with the strand and can be coupled to a mechanical or electromagnetic control device and locates the strand on the first or the second peripheral section. Band feeders of this Idnd however involve two different disadvantages, which are unacceptable, especially in their use in Imitting machines.

The first disadvantage consists in that the strand is drawn directly off a supply reel or the like during intermittent feed and can therefore only be fed with a comparatively high minimum tension. Tbs is dependent on the one hand on the number of deflecting points between the strand feed device and the supply reel and on the other hand on the un avoidable fluctuations in tension imposed by the use of the supply reel and is determined more or less arbitrarily. Since no active feed device is provided in intem-littent strand feed, unavoidable fluctuations in tension arise in this feed mode.

The second disadvantage consists in that, reliable changeover from positive to intermittent strand feed and vice versa presumes that the feed belt and the strand are in contact only over a small part of the circumference of the peripheral surface of the strand drum. Accordingly it is hardly possible to effect the positive strand feed without some slip between the strand drum and the feed belt, so that differing strand tensions are unavoidable even in positive strand feed.

The two disadvantages last referred to do not occur in strand feed devices of the kind initially specified, so-called storage feeders. In fact known strand feed devices of this kind (DETS 1760 600 or DETS 2 312 267) also have a strand guide element serving the purpose of selectively winding the strand off the storage drum tangentially -with a speed corresponding precisely to the winding on speed (positive strand feed) or drawing the strand over the lower edge of the storage druxn, substantially wdally, i.e. overhead, with a speed dependent on the quantity of strand consumed in the device (intermittent strand feed). In such strand feed devices the strand guide element can only be moved manually into the one or the other position, since it is not intended to bring the strand selectively into the one or the other position during running of the device using the strand, but is for setting the strand feed device either to permanent positive or permanent interrrdttent strand feed. In addition such storage feeders can be switched temporarily to intermittent strand feed if it is normally operating with positive strand feed, as is frequently desired during adjustment and repair work on knitting machines while substantially stationary or driven in creep mode.

The invention is accordingly based on the object of also designing the strand feeding device of the kind initially specified in such a manner that automatic changeover between positive and intermittent strand feed is possible.

The characterizing features of claim 1 serve to meet this object.

Further advantageous features of the invention appear from the dependent claims.

Tbrough the invention there is provided in the first place a strand feed device in the form of a storage feeder which can be set selectively and according to a pre-selected programme to positive or intermittent strand feed. Since the strand can be wound with a plurality of turn on the storage drum in both kinds of feed, there is the substantial advantage over belt feeders that the positive feed is ensured reliably and the strand is only subject to the small tension needed for the overhead take-off of the strand from the storage drum during intermittent feed. Apart is from this the control device can be made extraordinarily simple, since in essence only an electronically controllable solenoid or rotary magnet is needed for the setting of the strand guide element.

The invention will now be described in more detail in conjunction with the accompanying drawings of embodiments. These show:

Figure 1 an embodiment of the strand feed device according to the invention in a partially sectioned front view; Figures 2 to 5 two further embodiments of the strand feed device according to the invention, each in a partial front view and a partially sectioned plan view, to a larger scale than Figure 1; and Figures 6 and 7 a control device, shown schematically, with a setting member for selective adjustment of a strand guide element of the strand feed device according to Figure 1.

The strand feed devices shown in Figures 1 to 3 have a housing 1 fonned as a hollow body, which can be fixed at one end by means of a screw 2 to a mounting rail of device using a strand, e.g. a circular knitting machine. On the underside of the housing 1 there is arranged a storage drum 3, which is fixed to a drive shaft rotatably mounted in the housing 1. Two drive wheels 5 and 6, e.g. belt or toothed belt pulleys, serve for the drive of the shaft, being mounted coaxially and rotatably on an upwardly projecting part of the drive shaft. Between the two drive wheels 5 and 6 is mounted a manually shiftable clutch disc 7, coaxial with the drive shaft and so mounted on the projecting part of the drive shaft that it is rotationally fast with the drive shaft but can be shifted in the direction of a common axis 8 and coupled selectively to the drive wheel 5 or the drive wheel 6. The two drive wheels 5 and 6 are set in rotation by conventional drive elements 9 and 10, e.g. belts or toothed belts, where the drive elements can be driven with different speeds in the case of equal diameters of the drive wheels 5 and 6 or with equal speeds in the case of different diameters of the drive wheels 5 and 6. Alternatively it would be possible to provide only one drive wheel, in which case the storage drum 3 can only be driven at one speed of rotation.

On the free end of the housing 1 there is provided a support arm 11, on which there are arranged an in-feed eye 14, a strand brake 15, a slub monitor 16 1 and a further strand eye 17 for a strand coming from a conventional supply source, e.g. a supply reel. The free end of a sensor lever 18, pivotally mounted on the housing 1, terminates between the slub monitor 16 and the strand eye 17. A further strand eye 19, an out-feed eye 20 coaxial therewith but spaced therefrom and, arranged therebetween, a sensor lever 21 pivotally mounted on the housing 1 are fitted to a further support arm 22 fixed to the housing 1, this arm also serving as a support for a sensor unit 23, the strand eye 19 and out-feed eye preferably being coaxial with the axis 8 and being fixed fast on the support arm 22. On account of the described arrangement, the strand passes during intermittent strand feed in turn through the in-feed eye 14, the strand brake 15, the slub monitor 16, the sensor lever 18 bearing thereon and the strand eye 17, before it is fed substantially tangentially on to the peripheral surface of the storage drum 3 driven by the drive wheel 5 or 6. From the storage drum 3, on which the strand is wound in a plurality of turns to form a strand supply, the strand 12 is fed through the strand eye 19, over the sensor lever 21 and through the out-feed eye 20 to the device using the strand 12.

In this path from the, storage drum 3 to the strand eye 19 the strand 12 moreover passes through an air gap, which is formed by a brake ring 25 sitting on the storag c drum 3, and which can be omitted in positive strand feed, and the peripheral surface of the storage drum 3, before the strand 12 is fed to the device using it. In such an overhead - take-off of the strand 12 the storage drum 3 is rotated intermittently and in dependence on the strand usage and for this a clutch 13 arranged in the housing 1 but not described in detail is engaged or disengaged, i.e.

rotated or stopped. As soon as the strand supply on the storage drum. 3 falls below a minimum amount monitored by the sensor unit 23, the clutch 13 engages and the storage drum 3 is rotated. When the strand supply has then reached a predetermined maximum amount, likewise monitored by the sensor unit 23, the clutch 14 is disengaged, so that the storage drum 3 again stops. A preferred clutch 13 of this kind is known from DE-PS 2 743 749, to which reference is hereby expressly made.

Finally there can be fitted on or in the housing 1 a light 26 for indicating a strand breakage detected by the sensor levers 18 and 21, a manual switch 27 for manual actuation of the clutch for positive drive and the power supply 28 for the sensor arms 18 and 21, the sensor unit 23, the light 26 and the switch 27.

Strand feed devices of this kind and the functioning thereof are generally known (e.g. DE-PS 1760 600, 2 312 267 and 2 743 749) so that further (% 5 explanation can be dispensed with.

4b In the intermittent strand feed the strand 12 is drawn off over a lower edge of the storage drum 3, widening conically radially outwardly, while its contact point on the edge 30 can wander freely in the circumferential direction in known manner, depending on whether the storage drum 3 is at rest at the moment or is rotated with a circumferential velocity which is greater than, equal to or less than the take-off speed of the strand 12.

In order to make possible positive strand feed also, a strand guide element 31 is associated with the storage drum 3, according to Figure 1, which element is coupled to or formed as a part of an electromagnetic setting member 32. The setting member has a mounting plate 33 which is fixed to the support arm 22 by means of screws 34. In the particular case of Figure 1, the strand guide element 31 is formed as a pin with an axis 35 perpendicular to the axis 8 of the storage drum 3 and is slidable parallel to this axis 35, in that it is at the same time formed as the slidable armature of a solenoid forming the setting member 32. The strand guide element 31 can thus be set by means of the setting member 32 to a retracted first position, shown in Figure I in full lines, and a projected second position shown in Figure 1 in broken lines. The strand guide member 31 projects rearwardly out of the solenoid body in the first position.

The setting member 32 is arranged radially spaced from the axis 8 of the storage drum 3 by an amount which is greater than the radial spacing of the outermost end of the lower edge 30 from this axis 8. This distance is in particular sufficiently large for the retracted strand guide element 31 to leave enough of a gap between its front end facing the edge 30 for the customary overhead take- off of the strand 12 to be possible in intermittent and irregular strand feed. During this state the storage drum 3 is driven by means of the drive wheel 5 or 6 through the clutch disc 7 at a speed of rotation which is greater than the greatest possible take off speed of the strand 12 or is at least equal thereto. Accordingly a strand supply h fw 5 builds up on the storage drum 3 and is monitored by the sensor unit 23, leading to the known engagement and disengagement of the drive i.e. the clutch 13 of the storage drum 3.

If however the strand guid element 31 is in the projected second position, its front end so projects under the lower margin of the edge 30, radially in the direction of the axis 8, that it prevents further circulation round the edge 30 during overhead - take-off. In this case the strand can therefore only be drawn off with the same speed as it is wound on to the storage drum 3. Accordingly the storage drum 3 is driven in this case by means of the drive wheel 5 or 6 through the clutch 7 at a circumferential speed which corresponds precisely to the constant demand of the device using the strand. In this case the drive i.e. the clutch 13 is permanently engaged.

If the axis 35 of the pin-shaped strand guide element 31 is aligned radially with respect to the axis 8 of the storage drum 3, the direction of rotation of the storage drum 3 is optional. With other alignments of the strand guide element 31 it is however possible that it is only operative with one predetermined direction of rotation of the storage drum 3.

In the embodiment according to Figures 2 and 3, in which the same parts are provided with the same reference numerals, a strand guide element 38 is provided, which as in Figure I is formed as a pin 39, which is at the same time the armature of a solenoid forming a setting member 40. In contrast to Figure 1 the strand guide element 38 has a strand eye 41 in which the strand can be threaded on its end facing the storage drum 3, the eye being closed or partially open to facilitate laying in the strand 12. Moreover the axis of the strand guide element 38 is in accordance with Figure 2 not perpendicular but inclined and arranged at an angle to the axis 8 of the storage drum 3 lying between 90' and 180 relative to the downwards extension of the axis 8. In a retracted position of the strand guide element 38 shown in full lines in Figures 2 and 3 the strand eye 41 is so arrang -7 ed closely beneath the lower edge 30 and radially at approximately the level of its greatest diameter that the strand 12 can only leave the edge 30 through the strand eye 41 arranged in a fixed position, before it passes through the eyes 19, 20, but cannot carry out the circulating I C, 5 h movement around the edge 30 characteristic of intermittent strand feed. In this case the strand 12 is accordingly fed positively.

If however the strand guide element 38 and the strand eye 41 are located in a second position projected towards the axis 8, shown in broken lines in Figures 2 and 3, the strand eye 41 is substantially coaxial with the axis 8 and arranged a significant distance below the storage drum 3. In this case the strand 12 can accordingly be drawn off over the head, i.e. with intermittent strand feed. The distance of the strand eye 41 from the lower edge 30 of the storage drum 3 in this position is dependent mainly on the angle between the axis 8 and the axis of the pin 39 along which the displacement of the strand eye 41 takes place. An advantage of the strand eye 41 lies in that the strand is kept constantly under control even during the changeover from positive to intermittent strand feed and vice versa.

Furthermore the setting member 40 is fixed to a support arm 22a ofthe strand feed device by means of a mounting plate 42 and screws 42a similarly to Fill' re 1. Since the strand eye 41 has the same effect during intermittent feed as the Clu eyes 19, 20, the latter could even be omitted. The sensor lever 21 could be replaced by another device in this case.

In the embodiment according to Figures 4 and 5, in which the same parts are again given the same reference numerals, a strand guide element 43 is provided extending transversely to the axis 8 of the storage drum 3, this element being bent like a hook and coupled at one end to a rotary spindle 44 and provided in a central part with a receiving pocket 45 shaped like a jaw or an eye for the strand 12. The rotary spindle 44 is part of a rotary electromagnet forming a setting member 46 and can be rotated by this about an axis 47 running parallel to the axis 8.

The strand guide element 43 can be rotated by means of the setting member 46 at least into a first position retracted from the axis 8, shown in broken lines in Figure 5, and a second position projected towards the axis 8, shown in full lines in Figures 4 and 5. The setting member 46 is again arranged at a great enough radial spacing from the axis 8 for the strand guide element 43 to form a sufficiently large gap between itself and the lower edge 30 in the first position for the usual over-the 0 head take-off of the strand 12 to be possible, whereas it is arranged closely beneath the outermost radial margin of the lower edge 30 in its second position, in order to prevent the strand 12 running round this edge 30, as is necessary for positive strand feed. On account of the hook-shaped form of the strand guide element 43, the sense of rotation of the storage drum 3, the receiving pocket 45 of the strand guide element 43 and the sense of rotation of the rotary spindle 44 are so matched to one another that the strand 12 automatically falls into this receiving pocket 45 during positive feed and can come out of it without hindrance on switching to intermittent strand feed.

Furthermore the setting member 46 is fixed by means of a mounting plate 48 and screws 49 to a support arm 22b of the strand feed device.

Figures 6 and 7 shown the setting member 32 consisting of a solenoid of conventional construction to an enlarged scale. The setting member 32 includes in particular a magnetic winding 50, which has two terminals 52, 53 and is fixed on the mounting plate 33 having screw holes 51 for the screws 34. 71e two terminals are connected by electric wires to a current supply 54, i.e. a battery or the like, suited to whether a direct or alternating current magnet is involved. A switch 55 is connected in one of these wires and can be opened and closed by means of a relay 56, in order to bring the strand guide element 31 into the projected state by making the terminals 52, 53 to the current supply or into the retracted state by opening the switch 55.

The relay 57 is connected to an electronic pattern device 57, which forms with the relay 56, the switch 55 and setting member 32 an electronic control device for the strand guide element 31. The pattern device 57 can be formed in conventional manner and brings the strand guide element 31 into one or the other position in accordance with a pattern stored on a programme carrier, e.g. a stripe pattern. In particular the pattern device 57 for the strand guide element 31 can be a circuit arrangement known per se (DE-OS 3 909 817) which is connected to a pattern device for the needles of a knitting machine and which sends signals to the relay 56 in dependence on 1101' or 'T' signals, i.e. turns the relay 56 on or off, which appear as a predetermined signal sequence at the output of a pattern device for the knitting needles- In this manner it would be possible e.g. to energise the relay 56 constantly and thereby set the strand feed device to positive strand feed after a predetermined number of sequential needles have been selected to knit or 0 k 15 after the end of such a signal sequence, e.g. on appearance of the first signal selecting a needle to miss, to open the switch 55 again and thereby change over the strand feed device to intermittent strand feed again, before the predetermined number of sequential needles are again selected for knitting.

In addition it can be provided that, on the appearance of the knitting signals for the predetermined number of knitting needles it is determined by electronic means whether sufficient further knitting needles follow this sequence and accordingly whether the changeover to positive strand feed is actually necessary. The number of needles which will still knit the strand during the changeover phase can also be taken into account by means of suitable software.

The changeover instant from intermittent to positive strand feed or vice versa could alternatively be controlled by a sensing lever sensing the strand feed, in that there is a switch to positive strand feed on sensing a certain continuity in the strand feed, as takes place when all needles knit. If this continuity is no longer present, as is the case with irregular strand usage, e.g. during Jacquard selection of the knitting needles, operation is switched to intermittent.

The drive to the storage drum. 3 is moreover so controlled in known manner that the storage drum 3 is permanently coupled to one of the drive wheels 5 and 6 through the clutch 13 during positive drive, while in intermittent drive it is only coupled to one of the drive wheels 5 and 6 through the clutch 13 as required and at the same time, by means of the sensor unit 23, in such a way that a certain minimum supply of strand on the storage drum is ensured.

Further possibilities for controlling the relay 56 will be found in the state of the art (e.g. DE-PS 2 939 803, US-PS 3 418 831, US-PS 4 027 505), so that these need not be further explained.

In use of the described strand feed device with other strand-using machines, especially textile machines, corresponding possibilities for control arise. It is evident that the control device according to Figures 5 and 6 can also be used with the strand feed devices according to Figures 2 to 5, viz. with their setting members 40 and 46.

The invention is not limited to the described embodiments, in which many changes are possible. For example more than two drive wheels 5, 6 as well as means for stepless alteration of the speed of rotation of the storage drum 3 during positive strand feed could be provided. These means consist for example of a drive wheel of variable diameter, a steplessly variable gear or interchangeable gear-wheels within the drive for the feed and transport belts 9 and 10. Furthermore it would be possible to arrange the setting member 32, 40 or 46 radially inside the projection of the storage drum 3 rather than radially outside this projection. In addition other strand guide element than those shown and other than the setting members shown can be used. In particular it would be possible to use the armatures of solenoids or rotary magnets not directly as the strand guide elements or to couple them thereto but for example to provide between the strand guide elements and the armatures lever mechanisms or the like, for example to magnify the stroke of the strand guide element relative to the stroke of the magnet, or transmission members for the fastest switching operations.

- The closed or open solenoids of the firm Harting of D-4992 Espelkamp for example are suitable as solenoids, these being available with strokes of 3 to 24 nim.

In the use of rotary magnets the stroke of the armature created by a solenoid is converted into a rotary movement of a rotary spindle, which can be effected in known manner inside or outside the magnet body with the aid of a coarse thread coupling the armature to the rotary spindle.

It is further possible either to form the storage drum 3 as a rotary drum or to mount it in fixed position and this case to effect the winding on of the strand with an additional winding arm (DE-PS 1760 600). In place of the drive for the continuous or intermittent rotation of the storage drum 3 there is then a suitable drive for the winding arm.

The strand feed device according to the invention is suitable for use in conjunction with knitting machines, especially circular knitting machines, above all for the production of large area Jacquard patterns in plain-plain or plain-purl knitting or plain-purl plush knitting, where the strand feed takes place positively in large, un-patterned regions and intermittently in small patterned regions.

1

Claims

1. A strand feeding device with a storage drum having an axis and a lower edge, on to which the strand can be wound with a plurality of turns to form a strand supply, an out-feed eye, through which the strand can be drawn from the storage drun-4 and a strand guide element associated with the storage drum, arranged in the region of the lower edge and which can be adjusted into a first position for intermittent strand feed and a second position for positive strand feed, characterized in that the strand guide element (31;38;41;43) is coupled to an electromagnetic setting member (32,40,45) of an electronical control device.

2. A strand feeding device according to claim 1, characterized in that the strand guide element (31) consists of a pin movable transverse to the axis (8) of the storage drum (3).

3. A strand feeding device according to claim 1, characterized in that the strand guide element (38) consists of pin (39) movable obliquely relative to the axis of the storage drum (3) and carrying a strand eye (41).

4. A strand feeding device according to claim 2 or 3, characterized in that the setting member (32,40) is a solenoid coupled to the strand guide element (31,38) and designed to move this linearly.

5. A strand feeding device according to claim 2, characterized in that the strand guide element (31) is formed as the armature of the solenoid forming the setting member (32).

6. A strand feeding device according to claim 3, characterized in that the pin (39) is formed as the armature of the solenoid forming the setting member (40).

7. A strand feeding device according to claim 3, 4 or 6, characterized in that the strand eye (41) is arranged in the second position of the strand guide element (38) closely beneath the lower edge (30) of the storage drum (3) and is arranged in the first position of the strand guide element (38) significantly below the storage drum (3) and substantially coaxial therewith.

8. A strand feeding device according to claim 1, characterized in that the strand guide element (43) consists of a hook arranged transverse- to the aids (8) of the storage drum (3) and with a receiving pocket (45), the hook being mounted to rotate about an wis (47) running substantially parallel to the aiis (8) of the storage drum (3).

r %, 14k

9. A strand feeding device according to claim 8, characterized in that the strand guide element (43) is coupled to a rotary spindle (44) of a rotary magnet forming the setting member (46).

10. A strand feeding device according to any of claims 4 to 7, characterized in that the magnet is arranged radially spaced from the Mis (8) of the storage drum (3) by a distance which is greater than the greatest radial distance of the lower edge (30) of the storage drum (3) from this a)ds (8).

11. A strand feeding device according to any of claims 1 to 10, characterized in that the storage drum (3) is rotatably mounted for winding on the strand (12) and is provided with a controllable drive.