GB2134551A

GB2134551A - Sewing Machines

Info

Publication number: GB2134551A
Application number: GB08301256A
Authority: GB
Inventors: Peter Arthur Taylor
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-01-18
Filing date: 1983-01-18
Publication date: 1984-08-15
Also published as: GB8301256D0

Abstract

A sewing machine has a holding device in which a workpiece is clamped and which is mounted on a swing arm to be moved in translation to carry the workpiece along a predetermined circular path relative to a sewing position. Where the workpiece consists for instance of a strap to be attached to a satchel, document case or the like, the sewing effort is quite substantial, and in order to improve the quality of the goods by maintaining control of the sewing, the holding device (3,4) is supported in a machine frame (1,2) by means of thrust bearings (11, 12, 15). <IMAGE>

Description

SPECIFICATION Improvements in sewing machines This invention relates to sewing machines and pa rticolarly to machines for attachment of straps or the like to articles by a predetermined pattern of sewing in a localised area.

In such machines a workpiece is clamped in a holding device carried by a swing arm so as to move in translation during sewing to carry the workpiece along a predetermined path related to a sewing position.

In accordance with a first aspect of the invention, there is provided a sewing machine including a holding device for clamping a workpiece and movable to carrytheworkpiece in a predetermined path relative to a sewing position to generate predetermined patterns of stitching over a localised area, in which the holding device is mounted in a machine frame by means of an arrangementofthrust bearings to stabilisethe positions ofthe holding device and workpiece.

The arrangement ofthrust bearings may include opposed thrust bearings remote from the sewing position and a further thrust bearing surrounding the sewing position.

The holding device may be arranged to traverse full circular paths to generate circular lines of stitching.

In accordance with a second aspect ofthe invention, there is provided a sewing machine including a holding device for clamping aworkpieceand movable in a full circular path relative to a sewing position to generate a circular pattern of stitching on the workpiece.

In either aspect ofthe invention, the machine may comprise two similar and similarly movable spaced holding devices forconjoint movement to generate similar predetermined patterns of stitching at spaced locations of the workpiece.

Conveniently, the holding device comprises a bottom plate having an aperture in the region ofthe sewing position and a raisable foot is spring loaded so as to clamptheworkpiece between the foot and the bottom plate when in its lower position, and wherein the foot is spring loaded by springs acting directly in the direction of lowering.

The invention will be further described with refer encetotheaccompanying drawings, ofwhich the single Figure is a diagrammatic section showing relevant parts of a sewing machine in accordance with a preferred form of the invention.

The drawing shows a fixed machine member 1, and a machine frame member 2. A swing arm is shown as comprising a bottom plate 3 and a generally G shaped bracket member4 rigidly attached to the bottom plate 3.

An extension 5 of the plate3 is provided with an aperture 6through which a sewing needle (not shown) protrudes, defining a sewing position, during stitch forming. Thefree end of the bracket4 has a slide mechanism 7 mounted on it, and within this slide mechanism there is mounted a foot 8 aligned with the aperture 6. The foot 8 and its attached slide are spring loaded directlytowards the extension 5 by means of springs which are not illustrated in the Figure, and a mechanism (also not illustrated) is provided to retract thefootagainsttheaction ofthe springs and hold tin the retracted position for insertion and removal of the workpiece. Oncethefoot is released,the springs urge ittowards the extension 5 so that a workpiece located between the two is firmly clamped in position.The foot8 and extension 6thus constitutes a holding means.

A drive means, not shown, but involving a crank mechanism, is provided for causing the swing arm to move in a circular path relative to the members 1 and 2 sothatthe limited zone defined bythe apertures 6 and 8 moves around the needle during the sewing process and, in the preferred arrangement, the path is circular so that a circular stitching pattern is set up on the workpiece.

Sincethe machine is designed, for example, forthe attachment of straps, e.g. of leather or other stout material,to a backing piece, such as the flap of a satchel, document case orthe like, a very considerable effort has to be withstood during the sewing process, and in orderto react such forces adequately, it is proposed that the swing arm and holding device should be supported by an arrangement of thrust bearings.

In the arrangement shown, there is a first lower thrust bearing 11 1 shown substantially centrally ofthe lower plate 3 and opposed to an upperthrust bearing 12 which is located between a plate 13 bolted to the frame member 2 and a plate 14 adjustably attached to the G shaped bracket4. In addition,a second lower thrust bearing 15 is shown as being mounted in the member 1 in the region ofthe sewing position so asto surround the aperture 6 so asto supportthe extension 5 at all times during its precessional movement around the needle.

As an example, the G shaped bracket may for instance be of a width (through the plane of the drawing) of 1 inch (25 mm) or 1.5 inches (38 mm).

It is envisaged that in a preferred machine for carrying out the invention, there may be provided two sewing stations each having a swing arm and a holding device as illustrated, and thetwo swing arm may be actuated simultaneously by similar crank mechanisms, which will be driven from a common drive with the needle so as to provide proper synchronism with the stitch forming mechanism.

The space in between such holding devices may be adjustablesothatthe machine may be used for attaching two straps simultaneously at predetermined adjustable spacings.

Various modifications may be madewithin the scope ofthe invention.

1. A sewing machine including a holding device for clamping a workpiece and movable to carry the workpiece in a predetermined path relative to a sewing position to generate predetermined patterns of stitching over a localised area, in which the holding device is mounted in a machine frame by means of an arrangement ofthrust bearings to stabilise the positions of the holding device and workpiece.

2. A sewing machine as claimed in claim 1, in which the arrangement of thrust bearings includes

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in sewing machines This invention relates to sewing machines and pa rticolarly to machines for attachment of straps or the like to articles by a predetermined pattern of sewing in a localised area. In such machines a workpiece is clamped in a holding device carried by a swing arm so as to move in translation during sewing to carry the workpiece along a predetermined path related to a sewing position. In accordance with a first aspect of the invention, there is provided a sewing machine including a holding device for clamping a workpiece and movable to carrytheworkpiece in a predetermined path relative to a sewing position to generate predetermined patterns of stitching over a localised area, in which the holding device is mounted in a machine frame by means of an arrangementofthrust bearings to stabilisethe positions ofthe holding device and workpiece. The arrangement ofthrust bearings may include opposed thrust bearings remote from the sewing position and a further thrust bearing surrounding the sewing position. The holding device may be arranged to traverse full circular paths to generate circular lines of stitching. In accordance with a second aspect ofthe invention, there is provided a sewing machine including a holding device for clamping aworkpieceand movable in a full circular path relative to a sewing position to generate a circular pattern of stitching on the workpiece. In either aspect ofthe invention, the machine may comprise two similar and similarly movable spaced holding devices forconjoint movement to generate similar predetermined patterns of stitching at spaced locations of the workpiece. Conveniently, the holding device comprises a bottom plate having an aperture in the region ofthe sewing position and a raisable foot is spring loaded so as to clamptheworkpiece between the foot and the bottom plate when in its lower position, and wherein the foot is spring loaded by springs acting directly in the direction of lowering. The invention will be further described with refer encetotheaccompanying drawings, ofwhich the single Figure is a diagrammatic section showing relevant parts of a sewing machine in accordance with a preferred form of the invention. The drawing shows a fixed machine member 1, and a machine frame member 2. A swing arm is shown as comprising a bottom plate 3 and a generally G shaped bracket member4 rigidly attached to the bottom plate 3. An extension 5 of the plate3 is provided with an aperture 6through which a sewing needle (not shown) protrudes, defining a sewing position, during stitch forming. Thefree end of the bracket4 has a slide mechanism 7 mounted on it, and within this slide mechanism there is mounted a foot 8 aligned with the aperture 6. The foot 8 and its attached slide are spring loaded directlytowards the extension 5 by means of springs which are not illustrated in the Figure, and a mechanism (also not illustrated) is provided to retract thefootagainsttheaction ofthe springs and hold tin the retracted position for insertion and removal of the workpiece. Oncethefoot is released,the springs urge ittowards the extension 5 so that a workpiece located between the two is firmly clamped in position.The foot8 and extension 6thus constitutes a holding means. A drive means, not shown, but involving a crank mechanism, is provided for causing the swing arm to move in a circular path relative to the members 1 and 2 sothatthe limited zone defined bythe apertures 6 and 8 moves around the needle during the sewing process and, in the preferred arrangement, the path is circular so that a circular stitching pattern is set up on the workpiece. Sincethe machine is designed, for example, forthe attachment of straps, e.g. of leather or other stout material,to a backing piece, such as the flap of a satchel, document case orthe like, a very considerable effort has to be withstood during the sewing process, and in orderto react such forces adequately, it is proposed that the swing arm and holding device should be supported by an arrangement of thrust bearings. In the arrangement shown, there is a first lower thrust bearing 11 1 shown substantially centrally ofthe lower plate 3 and opposed to an upperthrust bearing 12 which is located between a plate 13 bolted to the frame member 2 and a plate 14 adjustably attached to the G shaped bracket4. In addition,a second lower thrust bearing 15 is shown as being mounted in the member 1 in the region ofthe sewing position so asto surround the aperture 6 so asto supportthe extension 5 at all times during its precessional movement around the needle. As an example, the G shaped bracket may for instance be of a width (through the plane of the drawing) of 1 inch (25 mm) or 1.5 inches (38 mm). It is envisaged that in a preferred machine for carrying out the invention, there may be provided two sewing stations each having a swing arm and a holding device as illustrated, and thetwo swing arm may be actuated simultaneously by similar crank mechanisms, which will be driven from a common drive with the needle so as to provide proper synchronism with the stitch forming mechanism. The space in between such holding devices may be adjustablesothatthe machine may be used for attaching two straps simultaneously at predetermined adjustable spacings. Various modifications may be madewithin the scope ofthe invention. CLAIMS

2. A sewing machine as claimed in claim 1, in which the arrangement of thrust bearings includes opposed thrust bearings remote from the sewing position.

3. Asewing machineasclaimed in claim 2, in which the arrangement of th rust bearings further includes a thrust bearing located to surround the sewing position.

4. Asewing machine as claimed in any of claims 1 to 3, in which the holding device is arranged to traverse a full circular path to generate a circular line of stitches.

5. A sewing machine including a holding device for clamping a workpiece and movable in a full circular path relative to a sewing position to generate a circular pattern of stitching on the workpiece.

6. Asewing machine as claimed in any ofthe preceding claims comprising two similar and similarly movable spaced holding devices forconjoint movementto generate similar predetermined patterns of stitching at spaced locations ofthe workpiece.

7. Asewing machine substantially as hereinbefore - described with reference to the accompanying drawings.

7. A sewing machine as claimed in claim 6, in which the spacing between the holding devices is adjustable.

8. A sewing machine as claimed in any of the preceding claim, in which the holding device comprises a bottom plate having an aperture in the region of the sewing position and a raisablefoot is spring loaded so as to clamp the workpiece between the foot and the bottom plate when in the lower position, and wherein the foot is spring loaded by springs acting directly in the direction of lowering.

9. Asewing machine substantially as hereinbefore described with reference to the accompanying drawings.

New claims or amendments to claimsfiled on 24th October 1983 Superseded claims 1-9

1. Asewing machine including a holding device for clamping a workpiece and movable to carrythe workpiece in a predetermined full circular path relative to a sewing position to generate a predetermined circular pattern of stitching, in which the holding device is mounted in a machine frame by means of an arrangement of annularthrust bearings to stabilise the positions ofthe holding device and workpiece.

3. Asewing machine as claimed in claim 2, in which the arrangement ofthrust bearingsfurther includes a thrust bearing located to surround the sewing position.

4. Asewing machine as claimed in any of the preceding claims comprising two identical and identically movable spaced holding devices for conjoint movement to generate identical predetermined single circular patterns of stitching at spaced locations ofthe workpiece.

5. Asewing machine as claimed in claim 4, in which the spacing between the holding devices is adjustable.

6. Asewing machine as claimed in anyofthe preceding claims, in which the holding device com prises a bottom plate having an aperture in the region ofthe sewing position and a raisablefoot is spring loaded so as to clamp the workpiece between the foot and the bottom plate when in the lower position, and wherein the foot is spring loaded by springs acting directly in the direction ofthe lowering.