WO2000036202A1

WO2000036202A1 - Method and device for sewing labels underneath fabric in a sewing machine

Info

Publication number: WO2000036202A1
Application number: PCT/EP1999/010005
Authority: WO
Inventors: Helmut Schips
Original assignee: Schips Ag Nähautomation
Priority date: 1998-12-17
Filing date: 1999-12-16
Publication date: 2000-06-22
Also published as: DE19858257A1

Abstract

The invention relates to a method and device for sewing labels underneath fabric in a sewing machine. In addition to including steps known from prior art (i.e. the label is clamped in a clamping device, inserted into the fabric below the sewing foot on the needle plate, the fabric is sewn with a seam, the clamping device is brought forwards by means of an advancing device, whereby the label is placed at least in the region of the fabric conveyor), the inventive method comprises the following: the clampingevice and the advancing device guide the clamped label over the fabric conveyor until the former is clearly affixed to the fabric, whereupon the clamping device is opened and the label and fabric are further conveyed by the fabric conveyor. Preferably, the speed at which the clamping device advances is synchronized with the speed of the fabric conveyor and the sewing speed. Several embodiments are described in order to carry out the inventive method. Common to all of these embodiments, the advancing device is arranged close to the sewing foot. Proposeddvancing devices include a combined stepper motor/spindle, a combined direct current synchronous motor/spindle and direct drives with direct current synchronous motors, direct current linear motors and pneumatic cylinders.

Description

Method and device for sewing labels under a fabric in a sewing machine

The invention relates to a method and a device for sewing labels under a fabric in a sewing machine. Such a method is required, for example, to sew a label onto the inside of the bundle of laundry items. For this purpose it is known to use a slide-in device, as is known, for example, from DE 27 32 488 C3, which goes back to the same applicant, and from CH 634 617.

In the first-mentioned DE 27 32 488, the label to be fed is fed under the fabric, the following process steps already being known:

1. Pinching a label in a clamping device which is arranged in front of a sewing head of a sewing machine.

2. Place the fabric with the sewing surface facing down under the presser foot on the needle plate.

3. Sew the fabric with a seam with the clamping device in the starting position.

4. Advance the clamping device with a feed device in such a way that the label reaches at least in the area of the mass transporter.

The above-mentioned process steps are known from the aforementioned DE 27 32 488. However, this has the disadvantage that this clamping device was only able to bring the label clamped in the clamping device only into the area of the fabric feeder and the sewing foot arranged above it. However, this had the disadvantage that, at the moment when the fabric feeder caught the clamped label, it was released from the clamping device and was transported into the sewing area due to the feed feeder's movement.

However, this had the disadvantage that it was possible to feed the label improperly, because the label was removed from the clamping device by the The fabric feeder is pulled out and brought into the sewing area via the fabric feeders.

The clamping device was pivoted according to the subject of this patent, i.e. the clamped label was fed into the sewing area (into the gripping area of the fabric feeders) due to a swivel movement.

However, such a pivoting movement is relatively imprecise and, above all, cannot be synchronized with the sewing feed movement.

There was therefore the disadvantage that the label was drawn in obliquely or insufficiently, which led to difficulties in later sewing.

In particular, the label could accidentally be sewn on at an angle, which was criticized.

The subject matter of CH 634 617 shows a further feed device for feeding labels under a fabric, which is placed on a needle plate, the feed device also consisting of a swiveling gripper clamp, between the gripping jaws of which the label is clamped. This clamping device had no feed device. It was arranged directly in front of the fabric feeder, so that here again there was the disadvantage that the label to be sewn was taken over directly by the clamping device into the fabric feeder and was guided by it into the sewing area. Here, too, there was a risk that the label could warp due to a different transfer process from the clamping device to the fabric feeder and was accidentally sewn on at an angle.

The invention is therefore based on the object of developing a method and a device operating according to the method so that a clean feeding of the label into the sewing area is possible with a label to be sewn under a fabric, without the risk that the label on Fabric is sewn at an angle or offset. To achieve the object, the invention proceeds from the known method steps 1 to 4 mentioned above and provides for further steps essential to the invention:

that after the label has been clamped and after the clamped label has been fed, at least in the feed area, the label is still held in a clamped manner and is guided in the sewing area in a clamped manner, whereby it is passed across the fabric feeders in a clamped manner and the label is held in a clamped manner until at least one One third of the label width the seam was completed.

An essential feature of the present method is therefore that the label with the clamping device and the associated feed device is no longer required only in the area of the material conveyor arranged in front of the sewing device, but that it is still held in a clamped manner and guided over the material conveyor in this clamping position is so that it is clamped in the sewing area and is held clamped until it is clearly fixed to the fabric by means of a seam.

Such a clear fixation is given, for example, when at least a third of the entire label seam has been clamped. However, the invention is not limited to this; it can also be provided that the clamping device is only effective until, for example, a quarter of the total seam to be made over the label has been completed.

After completion of the seam, which is sewn when the label is clamped, the clamping device is opened and the label and the fabric are continued in a manner known per se with the fabric transporter.

It was recognized as important here that warping of the label can be avoided if the feed speed of the clamping device is exactly synchronized with the speed of the material feeder (feed of the sewing material). For this reason, devices are claimed as essential to the invention which relate to feed devices which are able to move the clamping device synchronously with the sewing speed.

In a first, preferred embodiment, it is therefore provided that the clamping device is designed as a slide on which at least one holding clamp is arranged, the slide being arranged on a fixed guide and the feed device essentially consisting of a spindle on which a spindle nut is mounted is movable, which is fixedly connected to the carriage. It is further preferred here if the spindle is driven by a stepper motor, because the control of such a stepper motor enables a particularly sensitive and speed-accurate control of the rotational speed of the spindle.

The combination of a stepper motor with an associated spindle to form the feed device is claimed in a first embodiment as essential to the invention.

In a second embodiment, it is claimed as essential to the invention that the feed device consists of a direct current synchronous motor which is coupled to a control circuit (angle encoder). In this exemplary embodiment, too, the angle of rotation of the motor is precisely controlled by means of a control circuit, so-called angle of rotation encoders being used which make an exact, step-by-step, angle-dependent rotation of the direct current motor possible. In this way, it is possible to either drive the spindle via the above-mentioned rotary motor or also direct drive by means of such a direct current motor.

The third embodiment, which provides a so-called linear motor, points in the same direction. Such a linear motor is also controlled by means of direct current, cyclically and enables linear displacement via an exact, defined clock frequency, which brings about a defined displacement of the linear motor. In a fourth embodiment, the invention provides that the feed device consists of a pneumatic cylinder which also advances the carriage drive in a defined manner.

All of the exemplary embodiments have in common that the feed speed is exactly synchronized with the sewing speed. This can also be done by a mechanical positive coupling between the feed of the material and the feed of the mentioned clamping device.

In any case, it is important in all of the exemplary embodiments that the clamping device is effective until the label is sewn to a large extent to the fabric and there is no longer any danger that the label may warp or twist due to the further feed in the feed dog.

In addition to the special design of the feed device, a device for carrying out the method also provides that the entire feed device is arranged next to the presser foot.

This means that the entire clamping device can now be guided into the sewing area for the first time, which was not possible with the prior art arrangements mentioned at the beginning. In the prior art, this failed because the clamping device could only ever be fed in front of the presser foot and a further feed into the sewing area was not possible.

This is where the invention comes in, which provides that the entire feed device is pushed past the sewing foot, so that the clamping device connected to the feed device can bring the label into the sewing area at all, i.e. not only in the feed area, but directly in the area where the single needle or the double needle is arranged.

According to the invention, the insertion of the label in front of the fabric feeder is thus avoided and the clamped label is moved over the fabric feeder to such an extent that it certainly comes into the needle area and thus into the stitch area of the needle plate. The subject matter of the present invention results not only from the subject matter of the individual patent claims, but also from the combination of the individual patent claims with one another.

All of the information and features disclosed in the documents, including the summary, in particular the spatial design shown in the drawings are claimed to be essential to the invention, insofar as they are new to the prior art, individually or in combination. The invention is explained in more detail below with the aid of drawings which illustrate only one embodiment. Here, from the drawings and their description, further features and advantages of the invention that are essential to the invention emerge.

Show it:

FIG. 1: schematically, in plan view, an arrangement according to the invention with a label in the sewing position,

FIG. 2: a section through a detail in FIG. 1,

FIG. 3: a perspective side view of the fabric to be sewn with the label inserted,

Figure 4 is a perspective view of the clamping and

Feed device,

According to the invention, the method provides that the label 10 to be clamped is first clamped in a position 43 (preparation position) in a clamping device 8. The clamping device 8 is moved back into the retracted position (arrow direction 13 ') and the feed device 12, which drives the clamping device in the direction of displacement, is also in the retracted position.

Only the plan view of parts of the sewing machine arm is shown, where it is shown that one or more conveyors 2, 3 are arranged next to one another in parallel for the material transport. Between the carriers are one or several stitch holes 4, depending on whether it is a single-needle or a multi-needle drive.

The throat plate essentially has a front edge 7 located in the sewing direction, an outer side edge 6, an inner side edge 5 and a rear edge.

The clamping device consists essentially of Figures 1 and 4 of a bracket 9 which is rotatably held with a connection 21 in a cross member 23. The cross member consists of two mutually parallel and fixed to each other support legs 20, 22, which are firmly connected to each other by said cross member 23. The cross member 23 is fixedly connected to a carriage 24 which is guided on a fixed carriage guide 25 in the direction of arrow 13 and in the opposite direction.

A piston-cylinder arrangement 31 is articulated on the crossbeam 23 via a pivot bearing 34, the piston rod 32 of which engages on the free, pivotable end of a lever 30, the other end of which is connected to the connection 21 in a rotationally fixed manner. The connection 21 thus forms a pivot axis 33 for pivoting the clamp 9.

The clip is thus designed as a lever that can be pivoted on one side and is fastened to the support bracket 11.

The feed device 12 consists essentially of a spindle nut 26 which is fixedly connected to the cross member 23. This spindle nut 26 is displaceable on a spindle 27 in the arrow directions 13, 13 ', the spindle being held between two bearings 28. The two bearings are arranged in a carrier 29 which is fixedly attached to the sewing machine arm 1 as an angular carrier.

The spindle 27 is driven here by a belt wheel 36 which is driven by a toothed belt 35 which is looped by a further belt wheel 37 which is connected in a rotationally fixed manner to a drive shaft 38 which is driven by a stepper motor 42. In the illustration according to FIG. 4, only the motor bearing 39 is shown, which has a receptacle 40 in which the stepper motor 42 is fastened according to FIG.

For the sewing of the label 10 to a fabric 15 in connection with a fabric 14, reference is made to FIGS. 2 and 3 in connection with FIG. 4.

It can be seen that the label is first held in its ready position with its front edge at position 43 and the needles (or the double needles) make a seam 41 in the fabric 15, so that the rubber underneath is sewn onto the underside of the fabric 15 is, as can be seen in Figure 2.

At a certain point in time, which can be set in a programmable manner, the feed device 12 is started and the label 10 held in the bracket 9 in the support frame 11 is guided with its front edge from position 43 into the sewing area in the direction of arrow 13, the stepping motor 42 correspondingly drives the spindle 27 and the spindle nut is moved in the direction of arrow 13 upwards in FIG. 1.

In the position shown in FIG. 1 and FIG. 4, the label is introduced directly into the sewing area, i.e. thus in the area of the tap hole 4, which is shown in FIG. 1 as a single tap hole and in FIG. 4 as a double tap hole.

The seam is now attached to the label in connection with the fabric and the rubber until a quarter to 1 third of the label width has been sewn in the direction of the arrow 13, so that it is arranged firmly and without distortion under the fabric and under the rubber, as shown in Figure 2.

3 shows only for the sake of clarity that the lower edge of the fabric in FIG. 3 is folded up to make it clear that this label 10 is sewn to the underside of the fabric. In practice, however, this folded-up edge is arranged exactly flush on the throat plate 17 and below the presser foot 16.

FIG. 3 also shows a further variant, namely a variant in which no rubber 14 is used, but a bead which is folded in the form of a fold and surrounds the fabric.

Here, too, the label is sewn using either a double needle 18 and a double seam 41 or a single seam 19.

The design of the feed device as a spindle drive in conjunction with a stepper motor results in the essential advantage that the feed movement of the clamping device 8 in the sewing direction 13 can be precisely synchronized with the transport speed of the conveyors 2, 3. Therefore, after the label has been fixed with the help of the seams 19, 41, the label on the fabric is secured absolutely securely, without the risk that the transporters 2, 3 will bend, tilt or angle the label.

Instead of the feed device 12 shown with the spindle drive, however, the other embodiments mentioned in the general description part can also be used.

Drawing leqende

Sewing machine arm 25 guide

Transporter 26 spindle nut

Feed dog 27 spindle

Tap hole 28 bearings

Side edge (inside) 29 straps

Side edge (outside) 30 levers

Front edge 31 piston-cylinder arrangement

Clamping device 32 piston rod

Bracket 33 pivot axis

Label 34 swivel bearing

Carrier block 35 toothed belt

Feed device 36 belt pulley

Arrow direction 13 '37 belt pulley

Rubber 38 drive shaft

Fabric 39 engine mounts

Presser foot 40 holder

Stitch plate 41 seam

Double needle 42 stepper motor

Seam 43 position

Support leg

connection

Support leg

crossbeam

carriage

Claims

claims

1. A method for sewing labels under a fabric in a sewing machine, characterized in that the following process steps are carried out:

a) clamping a label (10) in a clamping device (8) which is arranged in front of a sewing head (16, 17) of a sewing machine.

b) Insert the fabric (15) with the sewing surface facing downwards under the presser foot (16) onto the needle plate (17).

c) Sewing the fabric (15) with a seam (19) with the clamping device (8) in the starting position.

d) advancing the clamping device (8) with a feed device (12) such that the label (10) reaches at least in the area of the stock conveyor (2, 3).

e) Further advancement of the clamping device (8) with the feed device (12) such that the label (10), which is still clamped, is passed over the material transporters (2, 3).

f) holding the label (10) which is still clamped in the clamping device (8) until the label (10) has been clearly fixed to the fabric (15) in order to remain unclamped in this position with respect to the fabric, essentially in its entirety Width to be sewn completely onto the fabric (15).

g) opening the clamping device (8) and continuation of the label (10) together with the material (15) by means of the material conveyor (2, 3).

2. A method for sewing labels under a fabric in a sewing machine, according to claim 1, characterized in that the label (10) is clamped by the clamping device (8) until the seam (19) at least a third of the label width over the Label (10) has been completed.

3. A method for sewing labels under a fabric in a sewing machine, according to claim 1, characterized in that the label (10) is clamped by the clamping device (8) until the seam (19) at least a quarter of the label width over the Label (10) has been completed.

4. A method for sewing labels under a fabric in a sewing machine, according to claim 1, characterized in that the feed speed of the clamping device (8) is substantially synchronized with the speed of the stock conveyor and thus the feed of the fabric (15).

5. A device for performing the method according to claims 1-4, characterized in that the clamping device (8) is designed as a carriage (24) on which at least one retaining clip (9) is arranged, the carriage (24) on a stationary guide (25) is arranged.

6. The device according to claim 5, characterized in that the feed device (12) consists essentially of a spindle (27) on which a spindle nut (26) is movable, which is fixedly connected to the carriage (24) and that the spindle (27) is driven by a stepper motor (42).

7. The device according to claim 5, characterized in that the feed device (12) consists essentially of a DC synchronous motor which is coupled to a control circuit.

8. The device according to claim 7, characterized in that rotation angle encoders are used in this control circuit of the DC synchronous motor.

9. The device according to claim 8, characterized in that the DC synchronous motor drives the spindle (27).

10. The device according to claim 8, characterized in that the DC synchronous motor drives the carriage (24) directly.

11. The device according to claim 5, characterized in that the feed device (12) consists essentially of a DC linear motor and thereby drives the carriage (24) directly.

12. The apparatus according to claim 5, characterized in that the feed device (12) consists essentially of a pneumatic cylinder and thereby drives the carriage (24) directly.

13. The apparatus according to claim 5 - 12, characterized in that the feed speed of the carriage (24) is substantially synchronized with the sewing speed.

14. The apparatus according to claim 13, characterized in that the synchronization is carried out by a mechanical positive coupling between the feed of the substance and / or the feed of said clamping device.

15. The apparatus according to claim 5-14, characterized in that the entire feed device (12) is arranged next to the presser foot (16), so that the clamping device (8) connected to the feed device (12) enables the label (10) to bring it near the sewing needle.