GB2087440A

GB2087440A - Thread Delivery Device

Info

Publication number: GB2087440A
Application number: GB8133817A
Authority: GB
Original assignee: Memminger GmbH
Current assignee: Memminger IRO GmbH
Priority date: 1980-11-14
Filing date: 1981-11-10
Publication date: 1982-05-26
Also published as: IT1146719B; GB2087440B; ES505079A0; IT8168483A0; DE3042957A1; JPS57107366A; ES8206684A1

Abstract

A thread delivery device is disclosed, particularly for supplying elastomer threads in circular knitting machines or circular hosiery machines. An endless belt (1) is guided in a horizontal plane along the periphery of the machine by means of guide rollers (2) mounted for free running, and is driven at a predetermined speed. It is in friction engagement with the peripheral surface of delivery spools (11) carrying the threads via a predetermined angle of grip in each case. Each of the delivery spools (11) mounted on a holder (9) for rotation about a vertical axis, is moveable, by means of its holder (9), towards and away from the belt (1) subject to the action of a resilient force loading it towards the belt (1). <IMAGE>

Description

SPECIFICATION Thread Delivery Device The invention relates to a thread delivery device, particularly for supplying elastomer threads in circular knitting machines or circular hosiery machines, having an endless belt which is guided in a horizontal plane by means of coaxial guide rollers mounted for free running and driven at a predetermined speed and which is in frictional engagement with the peripheral surface of delivery spools carrying the threads, over a predetermined angle of grip in each case, each of which delivery spools is mounted on a holder for rotation about a vertical axis.

Such a thread delivery device is known from the DE-OS 1 760 504. It has the advantage that the delivery spools are each driven at a constant peripheral speed by the endless belt regardless of their diameter, so that the speed of the thread delivery is also constant. In addition, only a single thread deflection is necessary up to the particular knitting system. Furthermore, knitting almost without tension is possible even with elastomer yarns. The comparatively long travel of the thread from the spool to the knitting system and the low inertia moment of the belt guide rollers render possible an effective reduction in tension in the thread on the way from the delivery spool to the knitting system.

In the known thread delivery device, the arrangement is such that the holders of the delivery spools are disposed fixed to the machine while the endless belt itself is guided in a loop over a resilient belt length equalizing device which automatically equalizes the alteration in the length of the belt effective for the spool drive, originating from the change in diameter of the delivery spools and so ensures that the belt always remains frictionally pressed against the peripheral surface of the delivery spools.Now when a single delivery spool has to be changed, which has become empty prematurely for example, on the one hand this is comparatively difficult because the travelling belt must first be kept away from this spool and on the other hand there is a risk that a brief alteration in the thread tension may be caused in the other knitting systems during this spool changing operation. In addition, irregularities at the periphery of a delivery spool may lead to brief local alterations in the belt speed which are rendered possible by the resilient belt length equalizing device and likewise cause an adverse effect on the uniformity of the thread delivery at all knitting systems.

It is therefore the object of the invention to provide a thread delivery device of the kind referred to at the beginning which, with a greater uniformity of the thread delivery at all knitting positions, permits a simple change of the delivery spools without the thread delivery conditions in the region of other delivery spools being adversely affected during the exchange of individual delivery spools.

In order to solve this problem, the thread delivery device according to the invention is characterised in that each delivery spool is mounted, by means of its holder, for movement towards the belt running over the guide rollers and away from this and is subject to the action of a resilient force loading it towards the belt.

Thus the effect is achieved that the belt length effective for the drive of the delivery spools is always kept constant. Each individual delivery spool can be uncoupled from the endless belt simply by being moved away and be changed, for example, without the thread tension at the other delivery spools being able to be influenced as a result. The thread delivery device easily permits the use of delivery spools with rims on the spool body because, when a delivery spool becomes empty, the belt can enter the space between the two rims without the spool changing operation itself being hindered as a result.

It is advisable for the resilient force, which presses the individual delivery spools with their peripheral surface against the belt, to be adjustable in its magnitude so that an adaptation to the particular operating conditions can be effected.

In a preferred form of embodiment, the arrangement is such that the individual delivery spool holders are each constructed in the form of a lever carrying a mounting spindle at one end which lever is mounted at the other end for pivoting about a vertical axis on a stationary support secured to the machine, the holder being subject to the action of a spring disposed between it and the support. This spring may appropriately be a helical spring with which there is associated a detent device for the selective alteration of its initial tension.

This construction of the thread delivery device has the advantage that with a large diameter of the delivery spool, the peripheral surface of the delivery spool is pressed with a greater force against the belt than is the case with a smaller diameter of the delivery spool, that is to say in the case of a delivery spool which is already nearly empty. Thus, as a result of the deflection of the holder with increasing reduction in size of the diameter of the delivery spool, an automatic reduction in the spring force acting on the holder is effected. This is particularly important when the machine is started up because with a large spool diameter, the starting resistance and the inertia moment of the delivery spools is greater than is the case with a small spool diameter.The greater pressure effective with a larger delivery spool diameter counteracts the risk of a slip occurring between the drive belt and the peripheral surface of the delivery spools during the starting or stopping of the machine. As a result, a farreaching careful treatment of the delivery spools is assured.

A guide roller may also be advantageously mounted on the support which can be fixed to the machine, in which case it is advisable for the guide roller to be mounted on a pin which simultaneously forms the pivot pin of the holder.

In addition, at least one holding means for a thread guide pulley may additionally be disposed on the support just as it is also possible to mount at least one thread breakage stopping device additionally on the support. In this manner, the support which can be secured to the machine, with the guide roller and the spool holder pivotally mounted on it as well as with the thread breakage stopping device and possibly the thread guide pulley, forms a constructional unit which greatly facilitates the mounting of the thread delivery device on the machine itself. Such a unit must merely be mounted for each knitting system: since only units of like construction are used, stocking is also simple while the thread delivery device can be used for any type of machine, regardless of the number of knitting systems.

In order to facilitate the mounting, each support may comprise a device for detachable securing to a supporting ring of the machine.

Finally, it is conceivable to adapt the mounting spindles of the individual supports to receive at least two delivery spools to be mounted one above the other and so to render possible a socailed double mounting as a result of which the space requirements and also the capital costs of the machine are reduced considerably.

One example of embodiment of the subject of the invention is illustrated in the drawing.

Figure 1 shows a thread delivery device according to the invention in detail, illustrated in perspective, Figure 2 shows another detail of the thread delivery device of Figure 1 in plan view and Figure 3 shows a support of the thread delivery device of Figure 1, on section on the line Ill-Ill in Figure 1 in a side view illustrated diagrammatically.

The thread delivery device, particularly for elastomer yarns, Lurex etc., illustrated in detail in Figures 1 and 2, comprise an endless belt 1 which is guided in a horizontal plane along the periphery of a circular knitting machine or circular hosiery machine, over a substantially circular path, and which may also be constructed in the form of a band. The belt 1 is driven by a driving wheel, not illustrated, round which it is wrapped and the diameter of which may be variable in the manner of a so-called patterning wheel and the drive of which is effected, for example, in fixed dependence on the machine drive shaft. The rotational speed of the endless belt 1 is therefore constant.

The endless belt 1 is guided over its circular path by a plurality of guide rollers 2 which may be constructed, for example, in the form of pin rollers with a low inertia moment. Each of the guide rollers 2 is mounted for rotation on a vertical spindle 4 by means of a rolling bearing 3, in the manner which can be seen from Figure 3, the vertical spindle being mounted for rotation in a support 5 which may be constructed in the form of a housing. The support 5 comprises a securing device n the form of a transverse groove 6 open at the edge, which is disposed at the end and into which a setscrew 7 projects and by means of which it can be fitted to a supporting ring, indicated at 8 (Figure 1), of the circular knitting machine or circular hosiery machine, the setscrew 7 then causing the fixed location.

Mounted on the spindle 4 for rotation therewith but not in relation thereto is a spool holder 9 which is constructed substantially in the form of a flat lever and which is connected at one end to the spindle 4 and at the other end carries a vertical mounting spindle 10 which, in the example of embodiment illustrated, is constructed in such a manner that two delivery spools 11 can be mounted thereon one above the other.

Connected to the spindle 4 is a helical spring which is indicated at 110 and which is anchored at the other side in a spring housing 12 which is rotatably mounted on the spindle 4. The spring housing 12 is provided with knurling at its outside at 1 3 and carries at its side adjacent to the holder 5 detent projections 14 which cooperate with corresponding detent elements of the support 5, indicated at 1 5.

The helical spring 110 exerts a torque in counterclockwise direction-in relation to Figure 1-on the spool holder 9 so that the peripheral surface of the lower delivery spool 11 mounted on the mounting spindle 10 is pressed from the outside resiliently agaisnt the belt 1 supported at each side of the delivery spool 11 by a guide roller 2, as can be seen from Figure 2. By appropriate turning of the spring housing 12, the initial tension of the helical spring 110 can be altered which means a corresponding alteration in the driving force occurring between the belt 1 and the peripheral surface of the delivery spool 11.

Secured to the support 5 is a holding means adapted in the form of a bracket 1 6 which is bent at an angle and on the end arm 17 of which, extending vertically with spacing beside the mounting spindle 17, there are disposed two thread breakage stopping devices 1 8 for the two associated delivery spools 11. Each of the thread breakage stopping devices 18 comprises a thread guide pulley 19 constructed in the form of a sensing member via which the thread indicated at 20 is supplied to the knitting position, not illustrated, of the knitting machine.

Thus with the spool holder 9 and the guide roller 2 mounted with this on the same spindle 4 as well as with the holding means 16 and the thread breakage stopping devices 18, the support 5 forms a fixed constructional unit which is mounted on the supporting ring 8 of the machine in a simple manner by means of the groove 6 and the setscrew 7, as explained. The number of these units corresponds to the number of threads to be supplied on a machine.

In operation, the de;ivery spools 11 are driven by the belt 1, rotating at a constant speed, at a constant peripheral speed, regardless of their particular diameter. Thus the thread delivery speed is also constant. With a full delivery spool 11, the associated holder 9, in relation to Figure 1, is at first swung comparatively far out which means that the helical spring 110 is relatively greatly tensioned and accordingly the pressing of the peripheral surface of the delivery spool 11 against the belt 1 is effected with a relatively great force. This is desirable because with a large diameter the inertia moment and the starting resistance of the delivery spools 11 are comparatively great and accordingly a greater pressing force is necessary to prevent a slip between the endless belt 1 and the delivery spools 11 during the starting and stopping of the machine.Such a slip would severely stress the delivery spools 11 and is therefore undesirable.

As the diameter of the delivery spool 11 decreases, the associated holder 9 is pivoted in counter-clockwise direction by the helical spring 11 as a result of which the helical spring 110 is relaxed to a certain extent. The consequence of this is that the pressure of the delivery spool 11 against the belt 1 automatically becomes less which is desirable in view of the inertia moment of the delivery spool becoming less with the diameter.

In a circular knitting machine or circular hosiery machine, the delivery spools 11 do not, as a rule, become empty at the same time. If one of the spools has to be changed, it is sufficient to swing the corresponding spool holder 9 outwards in clockwise direction by hand and so to uncouple the spool body from the belt 1. After a new delivery spool 11 has been mounted on the mounting spindle 10, the spool holder 9 is released so that the helical spring 110 can again apply the delivery spool with its peripheral surface against the belt 1. The thread delivery conditions at the other delivery spools 11 are not influenced during the spool change described.

The magnitude of the angle of grip with which the belt 1 wraps round the peripheral surface of the individual delivery spools 11 can be appropriately adjusted by appropriate dimensioning of the distance between the two adjacent guide rollers 2 or their support 5, in such a manner that a reliable coupling is ensured between the belt 1 and the peripheral surface of the delivery spool 11.

In the example of embodiment illustrated the spool holders 9 are each swingably mounted on the supports 5. Fundamentally, however, other forms of embodiment are also conceivable wherein the spool holders 9 are mounted, for example in a sliding guide, for movement towards the belt 1 and away from this, in which case the resilient force which presses the peripheral surface of the delivery spools against the belt 1 can be produced by a tension spring. Apart from this, in all forms of embodiment, the resilient force may for example, be produced by pneumatic means.

The diameter of the delivery spools 11 decreases as the course of the thread progresses.

By appropriate selection of the length of the spool holder 9 and the position of the spindle 4 it is possible to achieve that the delivery spools 11, as the diameter becomes smaller, as a result of the pivoting movement about the spindle 4, are moved simultaneously in the peripheral direction of the machine by the same amount as that by which the spool radius decreases. As a result, assurance is provided that the thread 20, running tangentially off the delivery spool 11, always runs onto the associated thread guide pulley 19 at the same angle 21 (Figure 2) regardless of the diameter of the delivery spool, so that even on a change of spool, this angle 21 remains at least substantially constant. This increases the operational reliability of the thread breakage stopping device 18.

Claims

1. A thread delivery device, particularly for supplying elastomer threads in circular knitting machines or circular hosiery machines, having an endless belt which is guided in a substantially horizontal plane along the periphery of the machine by means of coaxial guide rollers mounted for free running, and is driven at a predetermined speed and which is in engagement frictionally with the peripheral surface of delivery spools carrying the threads via a predetermined angle of grip in each case, each of the delivery spools being mounted on the holder for rotation about a vertical axis, and moveable on its holder towards and away from the belt subject to the action of a resilient force loading it towards the belt.

2. A thread delivery device as claimed in claim 1, wherein the resilient force is adjustable in its magnitude.

3. A thread delivery device as claimed in either claim 1 or claim 2, wherein each of the holders is in the form of a lever carrying a mounting spindle at one end and mounted at the other end for pivoting about a vertical axis on a stationary support secured to the machine, the holder being subject to the action of a spring disposed between it and the support.

4. A thread delivery device as claimed in claim 3, wherein a guide roller is mounted on the support.

5. A thread delivery device as claimed in claim 4, wherein the guide roller is mounted on a pin which simultaneously forms the pivot pin of the holder.

6. A thread delivery device as claimed in any one of claims 3 to 5, wherein the spring is a helical spring with which there is associated a detent device for the selective alteration of its initial tension.

7. A thread delivery device as claimed in any one of claims 3 tQ 6, wherein at least one holding means for a thread guide pulley is additionally disposed on the support.

8. A thread delivery device as claimed in any one of claims 3 to 7, wherein at least one thread breakage stopping device is held on the support.

9. A thread delivery device as claimed in any one of claims 3 to 8, wherein the support comprises means for detachable securing thereof to a supporting ring of the machine.

1 0. A thread delivery device as claimed in any one of claims 3 to 9, wherein the mounting spindle is adapted to receive at least two delivery spools mounted one above the other.

11. A thread delivery device as claimed in any one of the preceding claims, wherein in addition to the movement directed towards and away from the belt, a component of movement in the peripheral direction of the belt may be imparted to each of the holders, the magnitude of which component is in fixed dependence on the particular diameter of the delivery spool on that holder, such that the angle between thread running off tangentially from the delivery spool and a thread guide element through which the thread runs first is kept at least substantially constant regardless of the diameter of the delivery spool.

12. A thread delivery device substantially as described herein with reference to the accompanying drawings.