GB2064601A

GB2064601A - Improvements in or relating to apparatus for tensioning and guiding tubular workpieces for sewing machines

Info

Publication number: GB2064601A
Application number: GB8038204A
Authority: GB
Original assignee: Union Special GmbH
Current assignee: Union Special GmbH
Priority date: 1979-12-01
Filing date: 1980-11-28
Publication date: 1981-06-17
Also published as: FR2470816B1; FR2470816A1; IT1129389B; CH650293A5; IT8068825A0; GB2064601B

Abstract

Apparatus for tensioning and guiding tubular workpieces for sewing machines is disclosed in which there is associated with at least one (6, 7, 8) of a plurality of rotatable tensioning parts arranged to receive at least part of a tubular workpiece having an edge of an opening to be sewn, workpiece alignment means e.g. in the form of gear wheels (33) arranged in radial planes in an annulus around the axis of the part and each rotatable in its respective radial plane to move the workpiece transversely of the direction of feed to a stitch formation location, by rotation relative to the part of a worm 22 in response to a sensor device sensing, in advance of the stitch formation location, the position of the edge to be sewn. Alternatively the alignment means may be provided on a member disposed parallel to and adjacent the tensioning part. <IMAGE>

Description

SPECIFICATION Improvements in or relating to apparatus for tensioning and guiding tubular workpieces for sewing machines The present invention relates to an apparatus for tensioning and guiding tubular workpieces for sewing machines.

Workpiece tensioning and guiding devices for sewing machines for stretching and guiding tubular workpieces are known from, for example, German Auslegeschrift 1,072,871, and serve as an operating aid which assists an operator to stretch and guide the edge of an opening of a tubular workpiece.

German Auslegeschrift 2,514,794 discloses an attempt to automate the guidance of the stretched edge of a workpiece. In a device as described in the latter Auslegeschrift, an attempt is made to obtain a uniform course of the edge by a special design of the surface of the guide surfaces.

Although the device avoids manual guidance of the workpiece, the tensioning and guide device is rendered uneconomical by the time-consuming stretching and aligning of the workpiece which are required before the commencement of sewing.

German Offenlegungsschrift 2,730,291 describes a device which has an active control in order to align the edge of the material with the sewing location. In this device, it is unnecessary for the operator accurately to align the edge of the workpiece before the commencement of sewing, so that the stretching of the workpiece is less time-consuming. However, several idle rotations of the workpiece are generally required after the workpiece has been stretched, in order to align the edge of the workpiece with the sewing location, thereby resulting in the loss of the time gained during stretching.

According to the present invention there is provided apparatus for tensioning at least part of a tubular workpiece and guiding an edge of an opening thereof to be sewn at a stitch formation location of a sewing machine which comprises rotatable tensioning parts arranged to receive at least part of a tubular workpiece having an edge to be sewn and to enable an edge region thereof including the edge to be sewn to be fed to the stitch formation location of the sewing machine, a sensor device for sensing the position of the edge to be sewn, and workpiece alignment elements associated with at least one of the tensioning parts and arranged to displace at least said end region of a workpiece in a direction transversely of the direction of feed of the workpiece to the stitch formation location in response to the sensing by the sensor device of the position of the edge to be sewn, whereby, when in operation, to automatically align the edge to be sewn with the stitch formation location of the sewing machine.

Intensive displacement of the edge of the workpiece transversely of the sewing direction is rendered possible by arranging, in addition to the tensioning elements, controlled alignment elements which act transversely of the sewing direction, whereby the edge of the workpiece is placed into the desired position, and upon deviating from this position, can be realigned over a very short distance. Rotatable alignment elements disposed in an annulus around a tensioning part have the advantage that they can act in an unlimited manner in any direction transversely of the direction of sewing i.e. of the direction of feed of the workpiece to the stitch formation location, become effective over the entire loop of the workpiece, and can be controlled in a relatively simple manner.

The alignment elements can be arranged stationarily around the rotating tensioning parts, although they are more effective, as in one embodiment of the invention, if they rotate together with the tensioning parts. The tensioning parts can be mounted so as to be freely rotatable and can be driven by the feed of the sewing machine by way of the workpiece. Preferably, however, the tensioning parts and the alignment elements are connected to respective drives, wherein the alignment elements rotate together with the tensioning parts.

In another embodiment, the alignment elements are mounted in at least one rotating support member which is urged towards at least one of the rotatable tensioning parts.

Preferably, a rotating support member carrying alignment elements is mounted above the tensioning part disposed in advance of the stitchforming location in the direction of workpiece feed, the tensioning parts comprise rotatable cylindrical rollers, and the support member for the alignment elements comprises a counter-roller opposite the tension roller disposed in advance of the stitch-forming location, wherein the alignment elements are disposed in planes radially of the axis of rotation of the counter-roller, project beyond the outer surface thereof, and rotate each in its respective radical plane.

The invention will be further described by way of example with reference to the accompanying drawings in which: Fig. 1 is an elevation of a device according to one embodiment of the invention for sewing the edges of tubular workpieces, viewed from the operating side, Fig. 2 is a side elevation the device of Fig. 1, Fig. 3 is a portion of the device of Fig. 1, drawn to an enlarged scale, Fig. 4 is a plan view of the portion of Fig. 3, Fig. 5 is a cross section through a portion of the device, taken on the line A-B on Fig. 4, Fig. 6 is a cross section through the same portion of the device, taken on the line C-D of Fig. 5, Fig. 7 shows a different embodiment of a tensioning- and alignment element, Fig. 8 is an elevation of a device according to another embodiment of the invention, viewed from the operating side, Fig. 9 is a side elevation of the device of Fig. 8, Fig. 10 shows a portion of the device of Fig. 9, drawn to a larger scale, and Fig. 11 is a plan view of the portion of Fig.10, drawn to a larger scale.

Referring first to Figs. 1 to 6 of the drawings, a sewing machine 1 is mounted in a conventional manner on a table plate 2 which is carried by a support 3. A drive motor 4 for the sewing machine 1 is suspended from the table plate 2. The table plate 2 carries a switching- and control box 5 and tensioning parts 617 for stretching tubular workpieces. A guide 10 for the edge of the material of a workpiece, such as a conventional folder for hemming the edge, is located in advance of the sewing location of the sewing machine 1.

The tensioning parts 617 each comprise a cylindrical sleeve 6 which is closed at one end by a hemispherical shell 7. The cylindrical sleeve 6 is mounted on a cylinder 81 of a support member 8 so as to be axially displaceable. The support member 8 is provided with longitudinal slots 84 which are engaged by studs 11 on the casing 6, whereby the two parts are interconnected so as to be non-rotatabfe relative to one another. The sleeve 6 is connected to a piston rod 14 by means of driving member 13 and a roller bearing 12.

The support member 8 merges from the cylinder 81 into a V-shaped necked-down portion 82 having a flange 83 contiguous therewith. A drive member 16 is bolted to the flange 83 by means of bolts 15 and a flange 1 61. The drive member 1 6 has a hollow shaft 162 which is contiguous with the flange 161 and which is journalled in a support 18 by means of roller bearings 17, the support 18 being connected to a carrier 1 9.

A further hollow shaft 21 is mounted in the hollow shaft 162 and carries a worm 22 in the region of the flanges 83 and 161. That end of the hollow shaft 162 which extends out of the carrier 19 carries a gear wheel 23 axially adjacent to which is located gear wheel 24 mounted on the hollow shaft 21. The gear wheels 23, 24 are connected by way of respective toothed belts 25, 26 to respective gear wheels 27, 28 of motors 29, 30 which are secured to the carrier 19.

The mutually oppositely located surfaces of the flanges 83, 161 each incorporate respective halves of bores which are tangential to a coaxial circle around the worm 22 and in which are mounted spindles 32 of gear wheels 33. The gear wheels 33 are located in slots 34 which extend in planes radially of the axis of rotation of the worm 22. The gear wheels 33 mesh with the worm 22 on the one hand and, on the other hand, they project beyond the outer surfaces of the flanges 83,161.

The piston rod 14 extends outwardly through the hollow shaft 21 to a piston and cylinder drive 35 which is secured to the holder 19 by means of a bracket 36.

The holder 19 is secured to an arm 37 by means of a bolt 38. The bolt 38 engages through a slot 39 which is formed in the arm 37 and which permits adjustment of the holder 19 along the arm 37 and rotation thereof about the axis of the bolt 38. The arm 37 is connected to a tube 40 which is clamped in support clamps 41 which are secured to the table plate 2 and which permit adjustment of the tube 40 in an axial direction and rotation thereof.

Furthermore, the bolt 38 serves for securing a support 42 for a housing 43 in which a light source and a photoelement are disposed. The housing 43 is aligned such that it is located opposite a reflector 44 on the support 18.

In the embodiment of a tensioning part illustrated in Fig. 7, the support member 8 of Figs.

1 to 6, and the parts of the tensioning part contiguous therewith, are replaced by a hemispherical support member 45. The support member 45 also has a flange 83 which, together with the flange 161 of the drive member 16, forms the bearings for gear wheels 31.

The support member of Figs. 1 to 6 is chiefly used for the machining of longer workpieces, such as the hemming of undershirts, while the support member of Fig. 7 is used in the case of shorter workpieces, such as in the production of a waistband on shorts.

The mode of operation of the device will be described hereinafter with reference to the embodiment of Figs. 1 to 6.

A workpiece is stretched over the support members 8 and the gear wheels 33 of the tensioning parts 617 in a manner known per se, so that the edge of the opening is located approximately in the region of the reflector 44.

The device is then switched on, whereupon by means of the piston rod 14 the piston and cylinder drive 35 displaces the sleeve 6 towards the necked-down portion 82 in order to form a pleat in the vicinity of the edge of the material. This pleat facilitates subsequent alignment of the edge of the material, since it renders it possible to change the position of the edge of material without having to displace the entire workpiece transversely of the sewing direction.

After the pleat has been formed in the material, the support members 8 commence to rotate without the sewing machine 1 commencing to sew, that is to say, the presser foot is raised. The gear wheels 33 controlled by the photoelement than move the edge of the material into the desired position and into the guide device 10. This displacement of the edge of the material into the desired position is achieved by reducing and increasing the rotational speed of the motor 27 relative to the rotational speed of the motor 30, the two motors rotating in synchronism when the desired position is reached.

As soon as the desired position has been reached and the edge of the material has entered the guide 10, the sewing machine 1 starts. Whilst the edge of the material is running through the sewing machine, the edge of the material is realigned by the gear wheels 33 in the event of it leaving the desired position. As soon as the entire length of the circumference has passed through the sewing location, the sewing machine is stopped, the stopping of the sewing machine being controlled by measuring the sewn length or counting the stitches which have been sewn.

Upon stopping the sewing machine, the threads are cut in a manner known per se and the presser foot is raised, so that the workpiece can be removed.

It is generally sufficient to provide alignment elements only for the tensioning part which is disposed in advance of the sewing location in the direction of sewing. However, in the case of workpieces which are difficult to align, such as workpiece having a heavily corrugated edge, it is advantageous to equip both the tensioning parts 617 with controlled alignment elements.

The tensioning parts of the embodiment shown in Figs. 8 to 11 comprise cylindrical rollers 57, 58.

The roller 57 isjournalled in a holder 61 adjustably secured to an arm 62 which is in turn adjustably clamped to the table plate 2. The roller 58 is journalled in a holder 63 adjustably secured to an arm 64 which, like the arm 62, is adjustably clamped to the table plate.

A further arm 65 is pivotally mounted on the arm 63 and carries a further roller 66. Gear wheels 68 project from the roller 66 and are mounted in radial planes around the axis of rotation of the roller 66 and are driven by a worm on a wormgear shaft 72. The worm-gear shaft 72 is mounted in a drive shaft 73 for the roller 66. The drive shaft 73 carries a gear wheel 74 which is connected by way of a toothed belt 75 to a gear wheel 76 on the shaft of a drive motor 79. A further gear wheel 77 on the shaft of the drive motor 79 is connected by way of a toothed belt 81 to a gear wheel 78 on the shaft of the roller 58. The shaft of the motor 79 at the same time forms the pivot axis about which the arm 65 pivots on the holder 63. The arm 65 pivots the roller 66 towards the roller 58.

The roller 66 is raisably held against the roller 58 by its own weight or under the force of a spring.

The arm 65 carries a further motor 84 on the shaft of which is mounted a gear wheel 85. The gear wheel 85 is connected by way of a toothed belt 86 to a gear wheel 87 on the shaft 72.

The roller 57 can be mounted on the holder 61 so as to be freely rotatable and can be driven by the moving piece of material. In the illustrated embodiment, however, a motor 88 is provided on the holder 61 in order to drive the roller 57 in synchronism with the sewing speed.

Claims

1. Apparatus for tensioning at least part of a tubular workpiece and guiding an edge of an opening thereof to be sewn at a stitch formation location of a sewing machine, comprising rotatable tensioning parts arranged to receive at least part of a tubular workpiece having an edge to be sewn and to enable an edge region thereof including the edge to be sewn to be fed to the stitch formation location of the sewing machine, a sensor device for sensing the position of the edge to be sewn, and workpiece alignment elements associated with at least one of the tensioning parts and arranged to displace at least said end region of a workpiece in a direction transversely of the direction of feed of the workpiece to the stitch formation location in response to the sensing by the sensor device of the position of the edge to be sewn, whereby, when in operation, to automatically align the edge to be sewn with the stitch formation location of the sewing machine.

2. Apparatus as claimed in claim 1, in which the alignment elements are disposed in an annulus around the axis of rotation of at least one of the tensioning parts and are arranged to be rotated in planes lying radially of said axis of rotation.

3. Apparatus as claimed in claim 1 or 2, in which the alignment elements comprise toothed wheels which are disposed around a worm of a worm-gear shaft located coaxially with the axis of rotation of a tensioning part.

4. Apparatus as claimed in claim 3, in which a portion of the peripheries of the toothed wheels projects beyond the outer surfaces of the tensioning part with which they are associated.

5. Apparatus as claimed in any preceding claim, in which the alignment elements rotate with the associated tensioning part which which they are associated.

6. Apparatus as claimed in any of the preceding claims, in which the outer surface of at least the tensioning part with which the alignment elements are associated is provided with a necked-down portion between the free end and the alignment elements and in the vicinity of the alignment elements.

7. Apparatus as claimed in claim 6, in which the region of the surface of the tensioning part between the necked-down portion and its free end is axially displaceable.

8. Apparatus as claimed in any of claims 1 to 5, in which the outer surface of at least the tensioning part with which the alignment elements are associated extends spherically from the alignment elements to its free end.

9. Apparatus as claimed in one of the preceding claims, in which the tensioning part with which the alignment elements are associated has, for the edge of the workpiece to be sewn, a sloping contact surface which extends beyond the alignment elements axially away from its free end and sloped inwardly axially away from its free end and is contiguous with the alignment elements.

10. Apparatus as claimed in any preceding claim, in which drive shafts of the tensioning parts with which the alignment elements are associated and for the alignment elements are journalled one within the other and in a common bearing.

11. Apparatus as claimed in claim 10, in which the drive shaft of the tensioning part and the drive shaft for the alignment elements are each connected to a respective drive motor.

12. Apparatus as claimed in claim 11, in which the drive motors together with the tensioning part and alignment elements are secured to a carrier which is secured to an arm so as to be adjustable relative to the sewing location of the sewing machine both in respect of distance and of position.

1 3. Apparatus as claimed in one of the preceding claims, in which when in operation, the common rotational speed of the tensioning part with which the alignment members are associated and of alignment elements about the axis of said tensioning part is controlled in dependence upon the sewing speed of the sewing machine synchronous with the sewing speed of the sewing machine.

14. Apparatus as claimed in one of the preceding claims, in which, upon deviation of the edge of the workpiece from a desired position, the sensor device sensing the edge of the workpiece feeds correction data to an adjusting member which controls the rotational speed of the alignment elements each about its own axis.

15. Apparatus as claimed in claim 1, in which the alignment elements are mounted in at least one rotatable support member which is urged towards an associated one of the rotatable tensioning parts.

1 6. Apparatus as claimed in claim 15, in which a rotating support member carrying alignments elements is mounted above that one of the tensioning part which is disposed in advance of the stitch-forming location in the direction of feed.

17. Apparatus as claimed in preceding claim 15 or 16, in which the tensioning parts comprise rotatable cylindrical rollers, and the support member for the alignment elements comprises a counter-roller opposite that one of the tensioning rollers which is disposed in advance of the stitchforming location in the direction of feed, and in which the alignment elements are disposed in planes radially of the axis of rotation of the counter-roller, project beyond the outer surface thereof, and are rotatable each in its respective radial plane.

1 8. Apparatus for tensioning at least part of a tubular workpiece having an opening to be sewn in a sewing machine, constructed and arranged and adapted to operate substantially as hereinbefore particularly described with reference to and as illustrated in Figs. 1 to 6 of the accompanying drawings.

19. Apparatus as claimed in claim 18, embodying the modification constructed and arranged and adapted to operate substantially as hereinbefore particularly described with reference to and as illustrated in Fig. 7 of the accompanying drawings.

20. Apparatus for tensioning at least part of a tubular workpiece having an opening to be sewn in a sewing machine, constructed and arranged and adapted to operate substantially as hereinbefore particularly described with reference to and as illustrated in Figs. 8 to 11 of the accompanying drawings.