JPH0130512B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a feed rate adjusting device in a welt forming sewing machine, particularly in an automatic welt stitching machine for lockstitching work cloth.

[Conventional technology]

FIG. 2 is a perspective view of a main part of a conventional automatic welt sewing machine of this type, which is used to sew, for example, a flap cloth for an outer pocket onto the body fabric of a sewn product. Since this type of device is a known technology, the details will be omitted and only an overview will be explained.
A is the sewing machine body, B is the clamp device, C is the elevating body, and D is the sewing machine table. The workpiece is placed on the sewing machine table and moved forward in the X direction to proceed with the sewing work. The sewing machine main body A includes a needle bar 3, two needles N ₁ and N ₂ , and a light-reflecting fabric edge (detection) sensor S ₁ for detecting the front and rear edge positions of a flap cloth as a work cloth. , _S2 are arranged and fixed on the machine frame at a distance a in the X direction from the needle (described as _N1 ) (described as _S1 ). Clamp device B is
Each pair of large presser foot 13, receiving plate 14, flap presser foot 1
6, etc., and each flap presser 16 clamps the flap cloth onto the receiving plate 14 by inward rotation of each clamp arm 12 in the direction of the arrow shown in the figure. This clamp device B is configured to be able to reciprocate on the table D in the X direction. 16a is a flap presser 16
It shows the fabric edge detection hole drilled on the top. Also, 17
Reference numerals 4 and 18 indicate a presser foot of the elevating body C, and 4 and 18 indicate a center knife and a corner knife that can be retracted onto the surface of the table D, respectively.

The procedure for sewing the pocket flap cloth F onto the body fabric W is shown in FIGS. 3a, 3b, and 3c. _F1 ,
_F2 represents the front and rear edges of the flap cloth F in the X direction, S represents the flap cloth edge (detection) sensor position, N represents the needle drop position, and ST represents the seam.

Here, the sewing start position and sewing end position of the flap cloth F are required to precisely match the front edge _F1 and the rear edge _F2 of the flap, respectively, within an error range of approximately a fraction of a millimeter. . This is due to the quality of the sewn product and the corner knife 18.
This is to prevent problems caused by misalignment of the cutting portion (the cutting position is determined in relation to the sewing start position and the sewing length).

[Problem that the invention seeks to solve]

In order to determine the above flap sewing start position, a feed amount corresponding to the distance a from the position where the fabric edge sensor S detects the front edge of the flap fabric to the actual first needle drop position N is provisionally set in advance. In advance, trial sewing was actually performed on a test cloth different from the body material W of the sewn product, and the sewing position was confirmed using the actual material. If the trial sewing product is not in the desired correct position, use the adjustment switch of the stepping motor for feeding to reduce the above deviation to 0.1.
It was necessary to make corrections by making fine adjustments to the order of millimeters, perform test stitches again, check the actual product, and repeat the test stitches (that is, throw away stitches) until the required accuracy was achieved. The above necessity is due to a positional error when fixing the cloth edge sensor S to the sewing machine frame with a set screw or the like.

For this reason, conventional accurate sewing position setting requires a large number of man-hours and requires a large number of waste stitches, which is extremely uneconomical.

The present invention has been made in view of the problems of the prior art as described above, and has an object of providing a feed amount adjusting device that can accurately determine the sewing position without the need for actual trial sewing as described above. There is.

[Means for solving problems]

Therefore, in the present invention, when the sewing machine is in the cloth feed mode, the start switch is turned on, the cloth is fed to the needle drop position, and then the feed is stopped so that the sewing start position can be visually confirmed. The configuration is such that the stitching is fed by the sewing length when the next start switch is turned on, and then immediately stopped so that the sewing end position can be visually confirmed, allowing fine adjustments to both accurate positions without having to perform actual trial sewing. This allows for adjustments to be made.

〔Example〕

The present invention will be explained below based on examples.
FIGS. 1a and 1b are flowcharts of an example of the feed amount adjustment operation sequence for determining the accurate sewing start/end positions of the flap according to the present invention.
Each sequence is clear from the drawings, so a detailed explanation will be omitted and only the main points will be supplemented and explained.

In step 1 of FIG. 1a, first, an operating mode is set. The operating modes are (1) cloth feed mode, in which normal stitching of the sewing machine is inactive, and (2) normal sewing mode, (2) sewing machine operating, (3) above (2) + center knife operation mode, (4) above (3). + There are four types of corner knife operation modes, among which (1) cloth feeding mode is set. The start switch in step 2 is usually done with a knee switch, and the edge operation (again)
ON) to proceed to the next operation. At 10 points between step 3 and step 4, the front end _F1 position of the flap cloth is detected, the initially set feed amount is commanded, and a blank feed is performed, and in step 4, the position corresponding to FIG. 3b is reached. If YES in step 5, the feed will completely stop at the 11th section and the sewing start position can be visually checked. If there is a deviation from the desired position, the feed amount can be corrected by fine adjustment and the needle drop can be manually adjusted. Adjust to obtain the desired position while checking. Step 7 indicates turning on the start switch again, and the subsequent sequence is as follows:
This is a safety measure sequence to prevent damage to the needle due to the feed operation being performed when the needle is not in the upper position during the adjustment, and the sequence from step 6 onwards is a sequence for normal sewing with the center knife activated. This is the operation sequence, and step 8 shows the position corresponding to FIG. 3c.

Next, in step 9 of Fig. 1b, select YES.
At this time, the feed is completely stopped at the 12th section, and the sewing end position (that is, the sewing length) is visually checked and any necessary adjustments are made in the event of deviation in the same manner as in the case of the sewing start point. Also, step 10
The subsequent sequence is a safety measure sequence for the needle-up position that is exactly the same as that from step 7 onwards. Furthermore, the sequence regarding the corner knife operation after step 11 is applied when the flap cloth pocket is an inner type pocket.
If this pocket is an outer pocket,
Only the center knife is used, and a corner knife operation sequence is not necessary.

The operation sequence as explained above is
Since the hardware/software for implementing the conventional apparatus shown in the figure can be easily realized using known conventional techniques, the circuit diagram thereof will be omitted.

Furthermore, the principles of the invention are not limited to the case of flap attachment in the above embodiment, but can also be applied to the case of other work cloths having similar conditions.

〔Effect of the invention〕

As explained above, according to the present invention,
When attaching the workpiece using the welt forming sewing machine,
Since the accurate sewing position can be adjusted without repeating trial sewing as in the conventional method, it is possible to improve the number of man-hours and the uneconomical effect of waste sewing.

[Brief explanation of drawings]

FIGS. 1a and 1b are flowcharts of an example of the feed rate adjustment operation sequence of the present invention, FIG. 2 is a perspective view of the main parts of a conventional automatic welt sewing machine, and FIG. 3 is a flap cloth sewing sequence. This is a schematic diagram. A...Sewing machine body, N...needle drop position, S...
Cloth edge sensor position, W... Sewn body fabric, F... Flap cloth, F ₁ /F ₂ ... Front/back edge of flap cloth,
X...Work progress direction.

Claims (1)

[Claims] 1. Cloth edge detection means for detecting the position of the workpiece cloth edge;
In an automatic lockstitch hem sewing machine for attaching workpiece cloth, which is equipped with a feed amount adjustment means, when in sewing mode, the cloth feed motor and needle drive motor are linked, and stitch information stored in advance in RAM is used. control means for driving the automatic welt sewing machine to continuously form normal seams based on the sewing machine; and a control means for driving the automatic welt sewing machine so as to continuously form normal seams based on the sewing machine; A stopping means temporarily stops the workpiece cloth after the work cloth is fed to the first needle drop position by the operation of the control means and the start switch, and a stop means which temporarily stops the work cloth after the work cloth is fed to the first needle drop position by the operation of the control means and the start switch, and by the operation of the next start switch, it is fed to the sewing end position based on the stitch information. The sewing machine is equipped with a stop means for temporarily stopping the sewing machine after it has been fed to a predetermined sewing feed position, and a switch for selecting either the sewing mode or the cloth feeding mode can select either the sewing mode or the cloth feeding mode. A feed adjustment device for a welt forming sewing machine, characterized in that: