EP0950746A1 - Device for tensioning a fabric placed around the fabric shafts in an embroidering machine - Google Patents

Abstract

The fabric is stretched between rollers rotated in opposite directions by sprockets (25). Chains (27) with a smooth section (28') and a drive section (28) run from an actuator (29) over the sprockets (25) to springs (63). The fabric is tensioned when the drive section of the chain is on the sprocket but the rollers are free to rotate when the smooth section reaches the sprocket. The actuator (29') can be a manual rack (57) and pinion with a ratchet (61) and ratchet wheel or alternatively a pneumatically driven screwed spindle. The drive for moving the fabric forward on the rollers is connected through a pneumatic clutch.

Description

The present invention relates to a tensioning device for tensioning one around the fabric waves of an embroidery machine laid fabric by rotating at least one wave of fabric, with a driving wheel on one axis and one in a radius traction devices placed around the axis, a tensioner for shortening and extending the traction device and one against the Clamping direction acting on the traction spring, whereby Traction device and driving wheel can be coupled by pull on the traction device or can be uncoupled by relaxing the traction mechanism.

In the embroidery machine according to EP-B-0 148 127 leads a fabric web from a lower wave to an upper wave. The area of the fabric stretched between the waves forms the embroidery ground. If this area is embroidered, then he wound up on the upper fabric shaft and new embroidery base is subtracted from the lower fabric wave. The gate will according to the mass transfer from an upper position in move to a lower position.

In order to be able to embroider the embroidery ground, it must be tensioned be. This is done with a jig. To For this purpose, both material shafts can be rotated in opposite directions. On a ratchet wheel is attached to each fabric shaft a pawl attached to a drive pulley engages, when the jig is confirmed. At every Drive pulley is the end of a traction device, e.g. one Rope, which is attached to the drive pulleys it is looped that when the traction means is shortened the Drive pulleys are moved in opposite directions. Will the Clamp actuated, so the pawls snap into it Turn on the ratchet wheel and rotate the fabric waves with the movement of the drive pulleys carrying the pawls in opposite directions to each other, so that between the material waves existing embroidery base is stretched. So during the No one-sided tension on those stuck in the fabric Needles are created and thus the embroidery ground compared to the If the needles remain precisely aligned, the tensioner is opposite the gate slidably arranged.

For the initial winding of the embroidery base or the Unwinding from one and winding onto the other fabric shaft the material shafts must be freely rotatable. With no tension The respective pawl is therefore not engaged in traction means with the driving wheel.

There is also a further development of the described jig, which differs from this distinguishes that the jigs on Driver shafts are arranged so that the material waves can be replaced while the jig even stays at the gate. It was especially one Drive housing with pawl as a ring around the pawl or Driving wheels arranged around. On the drive housing of the upper and lower fabric wave is one end of each Traction means attached. When extending the traction device the drive housing by a spring against each Clamping direction rotated. The jack jumps through it displacement occurring over the teeth of the driving wheel. In Approaching a final position, it is finally against a bolt on the gate frame and out of the teeth of the Driving wheel lifted and lifted in the end position held. With this clamping device, however, proved Manufacturing costs for this drive housing as very high.

It is therefore an object of the invention to provide a simplified and to create less expensive clamping device which the same functions, especially when clamping with the traction device the material waves can be rotated to to tension the fabric and that the traction device from the fabric waves can be uncoupled so that they can rotate freely.

According to the invention this is achieved in that the Traction means guided directly around the driving wheel and the spring is arranged directly on the traction device.

By coupling directly between the traction device and Driving wheel takes place, the manufacture of the expensive Avoid drive housing with pawl.

As a rule, the axis is one with the material wave Couplable drive shaft for material shaft and Clamping device are independent of each other.

One is advantageous between the axle and the drive wheel Freewheel hub arranged so that the drive wheel against the Clamping direction freely on the axis or the fabric shaft in The clamping direction can rotate freely in the driving wheel. This makes it easier handling the jig by the traction device not out of engagement for each winding of the embroidery base the driving wheel is to be brought, or the traction means only withdrawn a small distance against the tensioning direction can then be used again from this position Rotate the fabric shaft in the tensioning direction.

The traction means can be a rope, a chain or a Toothed belt and the drive wheel corresponding to a roller Sprocket or a toothed belt wheel.

The traction means advantageously has a lot which Can engage with the driving wheel, and a batch, which transmit practically no torque to the driving wheel can. In particular, a chain expediently sometimes at least one game with, for example triple chain, with the sprocket two sprockets and has or has a sliding surface between them Timing belt expediently a toothed area and an area without teeth, which over a toothed belt wheel can slide.

So that the driving wheel and the traction device are uncoupled can, a spring is preferably provided, which Traction device against the tension force of the tensioner against one Position pushes or pulls in which with the drive wheel Interventionable part of the traction mechanism out of engagement with the driving wheel. By extending the traction device can Traction means and driving wheel are uncoupled. Either spread a spring pulls the traction mechanism away from the driving wheel so that it Driving wheel is uncoupled, or on the traction device against the Spring pulling the tension pulls the engaging engagement Area of the traction device from the driving wheel as soon as the traction device is released with the tensioner. In the former case it works a spring on the traction device so that it extended that or loosened traction device from the wheel so that the traction device is not in contact with the wheel when de-energized. In the latter case touches after extending the traction device only one area of the traction mechanism is the driving wheel, which is not Torque can be transferred to the wheel. This pulling off or Spreading the traction from the driving wheel causes a Uncoupling of traction device and driving wheel, so that the driving wheel can be rotated freely. The advantage of spreading away is that the driving wheel hardly needs to be turned for this, i.e. of the The embroidery base is only slightly relaxed.

Each wave is expediently at least assigned a clamping device on one side, for long ones Material waves preferably one on each side. For wrapping the fabric is proven on one side of the gate Manner with the clamping devices one coupling each connected, via which the material shaft from a drive driven and controlled the rotation of the fabric shaft can.

The driver shaft is advantageous by one to it parallel axis swiveling and in an adjustable Position ascertainable. So the fabric position can be adjusted be by the position of the axis of the jig and thus the position of the fabric wave or the embroidery base corrected for alignment with the needles.

Fig. 1

ein Gatter mit beidseitig an jeder Stoffwelle einer erfindungsgemässen Spannvorrichtung,

Fig. 2

eine vereinfachte Seitenansicht der linken Seite des Gatters aus Fig. 1,

Fig. 3

eine Kette für die Spannvorrichtung,

Fig. 4

eine Explosionszeichnung einer Spannvorrichtung gemäss Fig. 1 links unten.

Exemplary embodiments of the invention are described below with reference to the figures. It shows:

Fig. 1

a gate with on both sides on each material shaft of a tensioning device according to the invention,

Fig. 2

2 shows a simplified side view of the left side of the gate from FIG. 1,

Fig. 3

a chain for the tensioner,

Fig. 4

an exploded view of a clamping device according to FIG. 1 bottom left.

In Figure 1, an embroidery machine gate is shown with one stretched between two material waves 11 and 13 Embroidery base 15. The material waves 11, 13 extend from a side part 17 to a second side part 19 and rotatably supported in these. The storage of the material waves 11, 13 is carried out with two driver shafts 21, 23 each. On each Driving shaft 21, 23 is a driving wheel 25 for driving the Driver shaft 21, 23 and the fabric shaft 11, 13. To do that Driving wheel 25 is a chain 27 around, which with a Spanner 29,29 'is connected. Will with the tensioner 29.29 ' Chain 27 shortened, i.e. via the upper drive wheel 25 guided and the guided over the lower drive wheel 25 chain 27 contracted, the drive wheels 25 are rotated. This however only if there is an engaging part 28 of the chain 27 is wrapped around the drive wheel 25 and with this in Intervention is.

On the right side of the fabric waves 11, 13 is next to the means for tensioning a winding device in the Integrated side panel 19. For winding and unwinding the Embroidery base 15 serves a motor 31. The motor drives one Chain 33 and this on each drive shaft 23 a sprocket 35. The sprockets 35 can thanks to compressed air couplings 37 in Be engaged with the driver shafts 23. By the direction of rotation of the motor 31 and pressurizing it one or both couplings 37 are the material waves 11, 13 individually or together in one or the other direction rotatable. By turning the motor 31 to the left, for example the driving chain 33 pulled up, the upper one Corresponding material shaft 11 when clutch 37 is engaged turned to the left and therefore the fabric on top Material shaft 11 wound up.

So that the material shafts 11, 13 can be freely rotated the disengageable parts 28 of the chains 27 except Engagement with the sprockets 25 be. To do this, the tensioner 29, 29 'extended, with a spring (Fig. 2; 63) the chain 27 pulls back over the sprocket 25. With the so relaxed and extended chain 27 is the engaging triplex chain 28 no longer placed around the sprocket 25, but hangs behind the side panel 17,19 next to the sprocket 25. At Shortening the tensioner 29, 29 'is the chain 27 by Sprocket 25 pulled around. As soon as the triplex chain 28 is pulled around the sprocket 25, this hangs in the teeth of the chain wheel 25 and rotates it in the tensioning direction. If the material shafts 11, 13 rotate in the tensioning direction, the Embroidery ground 15 tensioned. The clamping force can be with the tensioner 29.29 'dosed and monitored with a suitable device become.

The tensioning device on the left side part 17 differs from the clamping device on the right Side part 19 in that it has no couplings 37, since the drive for winding only on the right side part 19 he follows. In addition, right side part 19 is a tensioner Air motor 41 shown, while on the left side part 17 shows another embodiment of a tensioner is, namely a simple, manually operated tensioner 29 '.

In the tensioner 29 with the compressed air motor 41 Spindle 43 rotated, which thereby fits into a mother tube 45 screwed in or unscrewed from the mother tube. This will the distance between those attached to the tensioner 29 Chain ends 47 shortened or lengthened and the chain 27 and at the same time the embroidery base 15 is tensioned or relaxed and solved.

No motor is provided in the tensioner 29 '. On a rotatable by hand with a lever not shown Shaft 49, a gear 51 and a ratchet 53 is arranged. The shaft 49 is supported in two jaws 55. Between Jaw 55, the gear 51 is arranged, which is engaged with a rack 57. The rack 57 is in one pipe 59 connected to the jaws 55. On a cheek 55 a pawl 61 is arranged, which with the ratchet wheel 53 cooperates. By turning the shaft to the right, the rack 57 moves into the tube 59 while the Pawl 61 slides over the teeth of ratchet wheel 53. This shortens the distance between those on the tensioner 29 ' fixed ends 47 of the chains 27, and an opposite Rotation of the shaft 49 is caused by the ratchet wheel 53 engaging pawl 61 prevented. The tensioners 29, 29 'are on the side parts 19, 17 slidably mounted.

In Figure 2, the clamping device is on the left side part 17 in FIG. 1 is shown in simplified form in a side view. The side part 17 is drawn cut. Of the Clamping device are only the two sprockets 25 and the chains 27 and the tensioner 29 'shown. The waves 21 and their storage are not shown. The chains 27 are drawn in two positions: each at the ends 47.65 of the chains 27 is tensioned with I and with II the resolved position. The chains 27 are on the one hand Tensioner 29, on the other hand attached to a spring 63. The Spring 63 is in turn at its other end on the side part 17 moored. It would also be possible to use the two chain ends 65 of the upper and lower chain 27 with a spring connect, and this spring on the side part 17 too fasten. In the loosened, extended or loosened Position II of the chains 27 is the spring 63, which at Extend the tensioner pulls back the chains 27, short and the tensioner 29 'long. The lots 28, which with the Sprockets 25 can be engaged, are not around the sprockets 25, but hang between the sprockets 25 and the springs 63 in the air. In the cocked position I are the chain ends 47 through the shortened tensioner 29 ' closer together, the other chain ends 65 moved apart accordingly and the springs 63 extended. The parts 28 are around the chain wheels 25 and are in Engaging with these. By shortening the tensioner 29 ' the chain wheels 25 become tensioned state of the chains 27 rotated, whereby the material waves 11, 13 rotated in opposite directions and the embroidery base 15 can be stretched. From the it is clear that the embroidery base 15 on that Side of the side parts 17, 19 must be on which the Springs 63 are arranged.

In Figure 3, the chain 27 can be engaged Lot 28 and the spring 63 shown. The chain 27 is made consisting of two parts: firstly the 28 'chain, which is not led over a sprocket, but over a sliding surface between two sprockets on the sprocket 25, and second, the triplex chain 28, which with the Chain axes 67 and the rollers arranged thereon in two Engage sprockets on sprocket 25.

Figure 4 shows the individual components in the Area of suspension of the driver shaft 21 and Sprocket 25. The lower drive shaft 21 is shown on left side part 17 of Figure 1. Two axes, namely the Driver shaft 21 and the pivot axis 69 sit in two Holding jaws 71.73. The driver shaft 21 is with bearings 75 stored in it while the pivot axis with screws 77 in the holding jaws 71, 73 clamped and in bores 79 in Side part 17 is introduced. This is about the pivot axis 69 whole part can be swiveled to the position of the embroidery base to adjust with respect to the needles, i.e. perpendicular to To adjust the fabric surface. This is done with a screw 81, which with a fork 83 in the holding jaw 73 interacts and is adjustable.

On the drive shaft 21 sits on two freewheel hubs 85 the chain wheel 25. This has a central region 87 on which the pull chain 28 'slides, and two Sprockets 89 left and right of which the triplex chain 28 can snap into place. So that the freewheel hubs 85 a can transmit sufficiently large torque, the Driver shaft 21 in the area 91, in which it with the Freewheel hubs 85 cooperates, a suitable diameter on. In the area of the bearings and in the head area 93, which one fits positively with the fabric shaft, the Driver shaft 21 the same dimensions as known Drive shafts. On the driver shafts 23 (see figure 1) on the right side of the gate is the sprocket 25 not laterally as with the drive shafts 21 with clamping rings 95 held, but the driver shaft 23 is on the corresponding point cut off, with the clutch 37 a coupling shaft is attached to the driving shaft 23. This clutch 37 gives the sprocket 25 the corresponding Stop. The clutch shaft has holes for the Compressed air supply to clutch 37.

Before tensioning an embroidery base 15 (see in The following figures 1 and 2) must be wound up. For this purpose, the fabric web 15 is around the upper 11 and lower 13 Placed on the lower shaft 13 wound up. To wind up the under fabric shaft 13 with Compressed air coupled to the drive, causing rotation of the motor 31 via the chain 33 and the sprocket 35, the Clutch disc and the bolt on it Coupling housing and the drive shaft 23 and thus on the Material wave 13 is transmitted. So the stuff with the Motor 31 wound on the fabric shaft 13. For winding up of embroidered fabric on the fabric shaft 11 becomes the top Coupling 37 coupled for the fabric shaft 11 and with the Motor 31 rotated the fabric shaft 11. In addition, the Tensioning device of the fabric shaft 13 does not hold it back. Therefore, the tensioners 29, 29 'are relaxed before the winding, so that the triplex chain parts 28 no longer engage with the sprockets 25. In this position II the Chains 27 can freely rotate the fabric shafts 11, 13. Then the fabric 15 is wrapped. For tensioning, be it after the Set up a new fabric to be embroidered 15 or after winding the embroidered fabric onto the Material shaft 11, the couplings 37 are relaxed, so that they cannot transmit power. Then the tensioner 29,29 'shortened as evenly as possible. This will get the Triplex chain sections 28 in the engaging position I. Now the sprockets 25 turn and the fabric is curious; excited. The freewheel hubs 85 transfer that to Sprocket 25 acting torque on the drive shaft 21.23. When the chain 27 is relaxed, on the other hand, it is the spring 63 is retracted with the sprocket 25 rotating freely and therefore the embroidery base 15 is only relaxed, but not is handled.

The traction means 27 and corresponding ones are analogous Driving wheels 25 can also be realized with a toothed belt and a toothed belt wheel or a rope and a roller, without the Deviate inventive ideas. Instead of or in addition to the freewheel hub 85 can also a spring 97 between Driving wheel 25 and traction means 27 may be arranged, which the Traction means 27 lifts off the driving wheel 25 as soon as the train on the Traction means 27 is minimized. A possible one is shown in FIG Execution variant drawn.

In summary it can be said that a Tensioning device for tensioning the embroidery base 15 between the Material waves 11, 13 of an embroidery machine gate a sprocket 25, over which a chain 27 is guided. Becomes the Tensioned on the chain 27, the chain engages a triplex chain section 28 into two sprockets, whereby the material waves 11, 13 by further shortening the Chain can be rotated. However, the chain extended, a spring 63 pulls the chain 27 back. Thereby the triplex chain section 28 disengages from the Sprocket 25. In a central area of the sprocket 25 with a sliding surface for the pull chain 28 ', this can the sprocket 25 slide without transmitting torque can. Therefore, in such a position II of the chain 27 over the same shaft 21.23 the fabric shaft 11.13 rotated and the fabric can be wound up or unwound over which the fabric is also tensioned without the tension and winding function hinder each other.

Claims (10)

Tensioning device for tensioning a fabric web (15) placed around the fabric shafts (11, 13) of an embroidery machine by rotating at least one fabric shaft (11, 13), with a drive wheel (25) on an axis (21, 23) and one in a radius the traction means (27) placed on the axis (21, 23), a tensioner (29, 29 ') for shortening and lengthening the traction means (27) and a spring (63) acting against the tensioning direction on the traction means (27), wherein traction means ( 27) and drive wheel (25) can be coupled by pulling on the pulling means (25) or can be uncoupled by relaxing the pulling means (27), characterized in that the pulling means (27) is guided directly around the drive wheel (25) and the spring (63) is arranged directly on the traction means (27). Clamping device according to claim 1, characterized characterized that the axis is a drive shaft (21,23), which can be coupled to the material wave (11,13) is. Clamping device according to claim 1 or 2, characterized characterized in that between the axis (21,23) and the Driving wheel (25) a freewheel hub (85) is arranged. Clamping device according to one of claims 1 to 3, characterized in that the traction means (27) is a rope and the drive wheel (25) is a roller. Clamping device according to claim 1 to 3, characterized characterized in that the traction means (27) is a chain or a toothed belt and the drive wheel (25) a chain wheel or is a toothed belt wheel. Clamping device according to claim 5, characterized characterized in that the traction means (27) a lot (28) which can engage with the driving wheel (25) and a lot (28 '), which is practical no torque can be transmitted to the drive wheel (25), in particular the chain (27) partially at least one is triple (28) and the sprocket (25) two Sprockets (89) and in between a sliding surface (87) has or the toothed belt a toothed and one Area without teeth. Clamping device according to one of claims 5 or 6, characterized by a spring (63,97), which the Traction means (27) against the clamping force in one position pushes or pulls in which the one with the drive wheel (25) Interceptible part (28) of the traction means (27) is not in engagement with the drive wheel (25). Clamping device according to one of claims 4 to 7, characterized in that on the traction means (27) Spring (63) is arranged and this spring (63) on one Embroidery machine gate is attachable, so that mounted device the spring (63) against the Tensioning direction pulls and the traction device (27) as soon as this is relieved with the tensioner (29, 29 ') the spring (63) is moved against the tensioning direction. Clamping device according to one of claims 4 to 8, characterized in that a spring force so on the Traction means (27) acts that their weight from Driving wheel (25) is able to lift off so that the traction means (27) not in engagement with the Driving wheel (25) is. Clamping device according to one of claims 2 to 9, characterized in that the driver shaft (21, 23) pivotable about an axis (69) parallel to it and in an adjustable position can be determined, so that the fabric position is adjustable.

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