ARM SEWING MACHINE

TECHNICAL AREA

The invention is related to an innovation in the pallet puller mechanism of a sewing machine.

KNOWN STATE OF THE ART

The pallet puller mechanism of the Feed Off The Arm sewing machines in the known state of the art is provided with a double-acting pneumatic piston acting as a pressure piston.

The pressure fork, which is positioned at the top of the double-acting pneumatic piston acting as a pressing piston, is pressed on the levers carrying the puller belt, and it is tried to ensure that the pallet puller mechanism, which is known in the art at the fold of the sewn fabric, moves in such a way as to ensure that the sewing stitch remains constant.

The force from the double-acting pneumatic piston acting as the pressing piston to the puller belt via the pressure fork must remain unchanged at the set value, so that the pallet puller mechanism in the known state of the art can pass through the folded of the stitched fabric by moving in the intended direction. When the force on the puller belt remains constant at the set value; when the puller, which pulls the fabric while sewing the cloth, is forced when passing through the fold of the stitched fabric, the pulling rate does not change and the sewing stitches remain constant. The pressure of the compressed air coming into the upper air inlet hole, which provides the downward movement of the double-acting pneumatic piston in order to keep the force on the puller belt constant, is adjusted by a regulator positioned on the hose connected to this hole. The pressure set in the regulator is constant if the pressure of the air coming from the system or the compressor is the same. When the pressure of the air coming from the system or the compressor changes, the pressure set in the regulator also changes. The change in the pressure set in the regulator causes the pressure force to change in the double-acting pneumatic piston, which causes the pressure force on the puller belt to change, which causes the unwanted seam structure to be formed at the stitching point of the sewn fabric.

In the known state of the art, the double-acting pneumatic piston presses the shaft downwards while the puller pulls the fabric. When the puller is pulling the fabric, the double-acting pneumatic piston shaft is forced upwards due to the thickness difference in the fabric fold. In the known state of the art, since the puller mechanism has a double-acting piston, this force is used to compress the air at the rear of the piston head. At high rates of speed such as 5000 cycles per minute, the air at the rear cannot be compressed by reacting quickly and elongation occurs in the fabric while the puller pulls the fabric. This causes the sewing stitch to be longer. The stitching, which continues with equivalent stitch intervals on the sewn fabric, can be long or short at a certain interval when passing through the fabric fold. This situation is absolutely undesirable by the customer.

The pallet puller mechanisms in the known state of the art in the Feed Off The Arm sewing machines in the known state of the art are provided with a regulator for adjusting the air pressure to the double-acting pneumatic piston. This regulator is an additional cost.

The double-acting pneumatic piston in the pallet puller mechanisms of the Feed Off The Arm sewing machines in the known state of the art is controlled and operated by a 5/2 directional control valve. The cost of the double acting pneumatic piston and the 5/2 directional control valve is high.

DEFINITION OF INVENTION

The invention solves the problems described above in a simple, inexpensive and ergonomic way.

In the pallet puller mechanism developed in the invention, there is a single-acting adjustable pneumatic piston acting as a pressure piston.

The single-acting adjustable pneumatic piston, which acts as a pressure piston, compresses the spring positioned on the upper side of the piston head by means of the pressurised air at the bottom of the piston head, and the spring is compressed and the shaft is waiting in the up position. The amount of spring compression is adjusted by means of an adjusting screw. When the single-acting regulated pneumatic piston, which acts as a pressure piston on the puller belt, needs to apply pressure, the core position of the 3/2 directional control valve is changed and the pressurised air at the bottom of the piston head is discharged. When the pressurised air at the bottom is discharged, the compressed spring moves downwards and provides the pressure of the pressure fork on the puller belt by means of the shaft with the force it is adjusted. The pressure fork does not directly press the puller belt, but presses the puller belt by means of the shaft or pulley series passing through the points where it is connected. This pressure force is constant, it does not change. For this reason, the desired stitching is obtained by ensuring that the puller mechanism moves in the desired way at the fold of the sewn fabric. When the compression force on the puller belt needs to be changed in case of changing fabric thickness or operations, the compression force of the spring on the piston head is changed by tightening or loosening the spring by means of the adjusting screw. A change in the force on the piston head means a change in the force from the piston head to the puller belt via the shaft and pressure fork. If we explain this situation on an example, for example, one thousand trousers obtained by sewing two fabrics with fabric thickness x will be sewn. Let P1 be the intended pressure force on the puller belt when the pallet puller mechanism passes through the fabric fold. The force P1 is obtained by compressing or loosening the spring by the adjusting screw. With the constant force P1 obtained, the pallet pullermechanism passes through the fabric fold while the puller belt is pressed. In a thousand trousers sewn from fabrics of X thickness, the compression force on the puller belt is a constant P1 force when the pallet puller mechanism passes through the fold. Then, two thousand trousers will be sewn from y-thick fabric. In this case, the puller belt is pressed by the constant force P2 obtained by tightening or loosening the spring of the adjusting screw according to the y thickness, while the pallet puller mechanism passes through the fold of the fabric. In this way, the desired sewing properties are obtained.

Since the reaction of the spring in the single-acting adjustable pneumatic piston is much faster when the pallet puller mechanism developed in the invention passes through the fabric fold, the piston shaft can move back faster (compress the spring a little more) at a speed of 5000 cycles. In this way, the synchronisation between the pulling speed of the fabric and the needle's penetration and extraction speed is not interrupted and the sewing stitch does not change.

The cost of the single-acting adjustable pneumatic piston in the pallet puller mechanism of the Feed Off The Arm sewing machine developed in the invention is low.

Since the palletpuller mechanism of the Feed Off The Arm sewing machine developed in the invention has a single-acting adjustable pneumatic piston, the single-acting adjustable pneumatic piston can be controlled and operated with a 3/2 directional control valve. This reduced the cost of the directional control valve.

PARTS AND COMPONENTS

1 . Feed Off The Arm Sewing Machine 1.1 Double Acting Pneumatic Piston

1.2 Puller Belt

1 .3 Pressure Fork

1.4 Regulator

1 .5 5/2 Directional Control Valve

1 .6 Single-Acting Adjustable Pneumatic Piston

1.6.1 Nut

1.6.2 Shaft

1.6.3 Coupling

1 .6.4 Front cover

1.6.5 Piston Head

1.6.6 Spring

1.6.7 Body

1.6.8 Adjusting Screw

1 .7 3/2 Directional Control Valve

10 Pallet Puller Mechanism in the Known State of the Art

20 Pallet Puller Mechanism

A Detail View

B Detail View

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 . Perspective view of the Feed Off The Arm sewing machine with the pallet puller mechanism in the known state of the art.

Figure 2. Perspective view of the Feed Off The Arm sewing machine with the pallet puller mechanism in the known state of the art.

Figure 3. A Detail view.

Figure 4. Side perspective view of the palletpuller mechanism in the known state of the art with regulator and 5/2 valve. Figure 5. Front perspective view of the pallet puller mechanism in the known state of the art with regulator and 5/2 valve.

Figure 6. Perspective view of a Feed Off The Arm sewing machine with the pallet puller mechanism of the invention.

Figure 7. Perspective view of a Feed Off The Arm sewing machine with the palletpuller mechanism of the invention.

Figure 8. B Detail View.

Figure 9. Front perspective view of the pallet puller mechanism of the invention with the 3/2 valve.

Figure 10. Side perspective view of the pallet puller mechanism of the invention with the 3/2 valve.

Figure 11. Perspective view of a single acting regulated pneumatic piston in assembled state.

Figure 12. Perspective view of the single acting adjustable pneumatic piston in assembled state.

DESCRIPTION OF INVENTION

The pallet puller mechanism (10) of the Feed Off The Arm sewing machines (1 ) in the known state of the art is provided with a double-acting pneumatic piston (1.1 ) acting as a pressure piston. The pressure fork (1 .3), which is positioned at the top of the double-acting pneumatic piston (1.1 ) acting as a pressure piston, is pressed against the puller belt (1.2) by means of the rollers to which it is connected, so that the pallet puller mechanism (10) in the known state of the art moves in the intended manner at the fold of the sewn fabric. The force from the double-acting pneumatic piston (1.1 ) acting as the pressing piston to the puller belt (1.2) via the pressure fork (1.3) must remain unchanged at the set value, so that the pallet puller mechanism (10) in the known state of the art can pass through the fold of the stitched fabric by moving in the intended direction. The pressure of the compressed air coming into the upper air inlet hole, which provides the downward movement of the double-acting pneumatic piston (1.1 ) in order to keep the force on the puller belt (1.2) constant, is adjusted by a regulator (1.4) positioned on the hose connected to this hole. The pressure set in the regulator (1.4) is constant if the pressure of the air coming from the system or the compressor is the same. When the pressure of the air coming from the system or the compressor changes, the pressure set in the regulator (1 .4) also changes. The change in the pressure set in the regulator (1 .4) causes the pressure force to change in the double-acting pneumatic piston (1.1 ), which causes the pressure force on the puller belt (1.2) to change, which causes the unwanted seam structure to be formed at the stitching point of the sewn fabric.

The double-acting pneumatic piston (1.1 ) in the pallet puller mechanisms (10) of the Feed Off The Arm sewing machines (1 ) in the known state of the art is controlled and operated by a 5/2 directional control valve (1.5). The cost of the double-acting pneumatic piston (1.1 ) and the 5/2 directional control valve (1.5) is high.

In the pallet puller mechanism (20) developed in the invention, there is a singleacting adjustable pneumatic piston (1.6) acting as a pressure piston. The singleacting adjustable pneumatic piston (1.6), which acts as a pressure piston (1.6.5), compresses the spring (1.6.6) positioned on the upper side of the piston head (1.6.5) by means of the pressurised air at the bottom of the piston head, and the spring (1 .6.6) is compressed and the shaft (1 .6.2) is waiting in the up position. The amount of compression of the spring (1.6.6) is ensured by means of an adjusting screw (1.6.8). When the single-acting regulated pneumatic piston (1.6), which acts as a pressure piston on the puller belt (1.2), needs to apply pressure, the core position of the 3/2 directional control valve (1.7) is changed and the pressurised air at the bottom of the piston head (1 .6.5) is discharged. When the pressurised air at the bottom is discharged, the compressed spring (1.6.6) moves downwards and provides the pressure of the pressure fork (1 .3) on the puller belt (1 .2) by means of the shaft (1.6.2) with the force it is adjusted. Even at high speeds, this compression force is constant and does not change because the spring reaction is faster than the pneumatic reaction. For this reason, the desired stitching is obtained by ensuring that the pallet puller mechanism (20) moves in the desired way at the fold of the sewn fabric. When the compression force on the puller belt (1.2) needs to be changed in case of changing fabric thickness or operations, the compression force of the spring (1.6.6) on the piston head (1.6.5) is changed by tightening or loosening the spring (1.6.6) by means of the adjusting screw (1.6.8). A change in the force acting on the piston head (1.6.5) means a change in the force acting on the piston head (1 .6.5) through the shaft (1 .6.2) and the pressure fork (1.3) to the puller belt (1.2). If we explain this situation on an example, for example, one thousand trousers obtained by sewing two fabrics with fabric thickness x will be sewn. Let P1 be the intended pressure force on the puller belt (1.2) when the pallet puller mechanism (20) passes through the fabric fold. The force P1 is obtained by compressing or loosening the spring (1.6.6) by the adjusting screw (1.6.8). With the constant force P1 obtained, the pallet puller mechanism (20) passes through the fabric fold while the puller belt (1.2) is pressed. In a thousand trousers sewn from fabrics of X thickness, the compression force on the puller belt (1.2) is a constant P1 force when the pallet puller mechanism (20) passes through the fold. Then, two thousand trousers will be sewn from y-thick fabric. In this case, the puller belt (1.2) is pressed by the constant force P2 obtained by tightening or loosening the spring (1.6.6) of the adjusting screw (1.6.8) according to the y thickness, while the pallet puller mechanism (20) passes through the fold of the fabric. In this way, the desired sewing properties are obtained.

The pressure fork (1.3) does not directly press the puller belt (1.2), but presses the puller belt (1.2) by means of the shaft or pulley series passing through the points where it is connected.

The invention provides a pallet puller mechanism (20) of the Feed Off The Arm sewing machine (1 ), comprising a single-acting adjustable pneumatic piston (1.6) which presses the puller belt (1.2) at the desired constant force by means of shafts or rollers passing through the points where the pressure fork (1.3), which is positioned on the shaft (1 .6.2), is connected.

Single-acting adjustable pneumatic piston (1.6) in the pallet puller mechanism (20) of the invention,

- positioned behind the spring (1.6.6) positioned on the upper side of the piston head (1.6.5), by turning the spring (1.6.6) in one direction (e.g. clockwise), the spring (1.6.6) is compressed, thereby increasing the force acting on the piston head (1.6.5) on which the spring (1.6.6) acts,

- by turning the spring (1.6.6) in the opposite direction (anticlockwise), the spring (1.6.6) is released, thereby reducing the force acting on the piston head (1 .6.5) on which the spring (1 .6.6) acts,

It includes the adjusting screw (1 .6.8) which allows the force on the piston head (1 .6.5) to be adjusted.

The single-acting adjustable pneumatic piston (1.6) in the pallet puller mechanism (20) shown in Figure-12 and developed in the invention is assembled as follows: The shaft (1.6.2) with nut (1.6.1 ) attached to its front side is inserted into the piston head (1.6.5) through the centre hole of the front cover (1.6.4). There are sealing elements on the piston head (1.6.5) and the front cover (1.6.4). After positioning the spring (1.6.6) at the rear of the piston head (1.6.5), the body (1.6.7) is mounted on the front cover (1.6.4) so as to enclose the spring (1.6.6) and the piston head (1.6.5). The adjusting screw (1.6.8) is then positioned at the rear of the body (1.6.7) so that it is located behind the spring (1.6.6). There are external threads on the adjustment screw (1.6.8) and it is screwed to the internal threads in the hole where it is mounted on the body (1.6.7). When the adjusting screw (1 .6.8) is turned in a direction according to the thread on it, e.g. clockwise, it moves downwards and presses the spring (1.6.6) and compresses the spring (1.6.6). When turned anti-clockwise in the opposite direction, the adjusting screw (1 .6.8) moves upwards, releasing the force on the spring (1 .6.6) and loosening the spring (1 .6.6).

The adjusting screw (1 .6.8) can be of any suitable external thread size.

The part of the adjusting screw (1 .6.8) which is turned by holding it can be of any suitable geometrical shape (circular, hexagonal, etc.).

The coupling (1 .6.3) is positioned on the front cover (1 .6.4).