JPS6116195B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an upper feed mechanism of a sewing machine.

Conventionally, as shown in Fig. 1, overlock sewing machines, etc. have an upper feed that feeds the cloth in four movements in cooperation with the lower feed dog F in order to improve the feeding force of the cloth, stretch the cloth, or form scratches. Top feed mechanisms with teeth are known.

As shown in the figure, this upper feed mechanism is swingably supported by pins 3 and 4 fixed to a presser foot arm 2 having a presser foot 1, and includes an upper feed arm 5 having an upper feed tooth 5A at its tip, and an upper feed arm 5 having an upper feed tooth 5A at its tip. The pin 6 provided on the feed arm 5 and the pin 6
The swing arm 7 is fitted with the upper feed dog 5A to provide four motions to the upper feed dog 5A.

As shown in FIG. 2, the upper feed arm 5 and the upper feed dog 5A make four movements using a pin 3 fixed to the presser arm 2 as a fulcrum, and the position of this pin 3 is such that the upper feed dog 5A is always in the position when the cloth is transferred. It is set to be in a substantially horizontal state.

For this reason, when sewing stretchable materials such as stockinette or non-stretchable materials, the upper feed dog cannot move in accordance with the characteristics of the material, resulting in puckering, twisting, etc. The disadvantages are that the feeding force varies depending on the material and that good sewn products cannot be obtained.

SUMMARY OF THE INVENTION The present invention provides an upper feed mechanism for a sewing machine that can eliminate the above-mentioned drawbacks by varying the inclination of the upper feed dog depending on the fabric material.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 3 shows an exploded perspective view of the upper feed mechanism of the present invention.

In the figure, reference numeral 10 denotes a support stand rotatably supported on a machine frame (not shown) around a horizontal axis 11;
13 is a vertical shaft rotatably supported on the support base 10 about a vertical axis, and 13 is a cloth presser whose base end is rotatably supported on the vertical shaft 12 and has upper and lower through holes 14 and 15 at the tip. This is a presser foot arm having a diameter of 16. Therefore, the presser arm 13 can rotate vertically about the horizontal axis 11 and horizontally about the vertical axis 12.

Reference numeral 17 denotes a lower feed dog 1 that moves in conjunction with a main shaft (not shown) and moves forward and backward relative to the throat plate (not shown).
It is a swinging arm that moves four times as shown by the arrow Y in synchronization with 8, and has a pin 19 projecting horizontally from its tip.

20 is a hole 20A opened at the base end of the presser foot arm 13.
The annular body 20 is rotatably supported, and the rotational position of the annular body 20 can be maintained by an adjustment screw 21 screwed into the upper surface of the presser arm 13.

22 is a screw hole opened in the annular body 20 at a position eccentric from the center of the annular body 20, and the screw 2 is inserted into this screw hole 22.
3 is screwed in, and a square piece 25 serving as a support member is rotatably supported via a ring 24.

Therefore, since the square piece 25 supports the screw 23 at an eccentric position by rotating the annular body 20, its vertical position can be varied.
Reference numeral 26 denotes a feed arm having a forked portion 27 at the base end and an upper feed tooth 28 at the tip that loosely fits into the upper and lower through holes 15 and 16 of the presser foot 16, and the tip of the presser foot arm 13 at the tip of the feed arm 26. A hole 30 that fits loosely into a pin 29 provided in
A support hole 31 is provided in which a pin 19 provided on the swing arm 17 is fitted.

The four movements of the swing arm 17 are transmitted to the feed arm 26 via the pin 19, causing the feed arm 26 to make four movements around the square piece 25 serving as a support member.

Next, the operation of this invention will be explained.

When sewing ordinary cloth, the annular body 20 shown in FIG. 3 is rotated to set the height of the screw hole 22 at an intermediate level, and the position is fixed by tightening the screw 21.

Thereafter, when the sewing machine is started, as shown in FIG.
The upper feed dog 28 as shown in the figure moves in a trajectory parallel to the bed surface B during cloth feeding.
Next, when sewing relatively easily stretchable cloth such as stockinette, the annular body 20 is rotated to set the height of the screw hole 22 to the highest height, and the screw 21 is tightened to fix the position.

After that, when the sewing machine is started, the feed arm 26 moves four times within the range regulated by the pin 29 and the hole 30, centering on the square piece 25 at the uppermost position, as shown in FIG. During cloth feeding, the upper feed dog 28 moves in a trajectory that is inclined by α° to the right with respect to the bed surface B.

For this reason, the upper feed dog 28 and the lower feed dog 18 come into contact only at a portion away from the needle to the right, so during cloth feeding, the upper feed dog 28 and the lower feed dog 18 close to the needle
A gap is created between them. For this reason, easily stretchable fabrics such as knitted fabrics are sent to the upper feed dog 28 and lower feed dog 18 so that they are not stretched abnormally but rather contracted before being sent to the sewing area, so that even if the upper differential ratio is small, it will not work normally. It will be sewn together as a cloth.

When sewing a cloth that is relatively difficult to stretch, the annular body 20 is rotated to set the height of the screw hole 22 to the lowest level, and the screw 21 is tightened to fix the position.

After that, when the sewing machine is started, the feed arm 26 makes four movements within the range regulated by the pin 29 and the hole 30, centering on the corner piece 25 at the lowest position, as shown in FIG. 6. During cloth feeding, the upper feed dog 28 moves in a trajectory inclined to the left by β° with respect to the bed surface B.

For this reason, the upper feed dog 28 and the lower feed dog 18 come into contact with each other from the left side closest to the needle, and the fabric between the needle and the upper feed dog 28 and lower feed dog 18 does not play before being sewn with the needle. To reliably feed the cloth to a sewing section and to stitch it in a normal state without the cloth running out or shrinking.

As described above, according to the present invention, the supporting member, which is the center of swing of the feed arm having the upper feed dog, is moved up and down and is supported on the presser foot arm in an adjustable manner, so that the inclination of the upper feed dog can be adjusted to the fabric material. By adjusting accordingly, it is possible to obtain good quality sewn products with beautiful seams for various materials.

[Brief explanation of the drawing]

Fig. 1 is a front view of a conventional upper feed mechanism, Fig. 2 is a schematic diagram showing the movement of the upper feed dog of the mechanism shown in Fig. 1, and Fig. 3 is an exploded perspective view of an embodiment of the mechanism of the present invention. 4 to 6 are front views showing the movement state of the upper feed dog of the mechanism shown in FIG. 3. 13... Presser arm, 17... Rocking arm, 25...
Support member, 26... feed arm, 28... upper feed dog.

Claims (1)

[Scope of Claims] 1. A presser foot arm whose base end is rotatably supported on the machine frame around a horizontal axis, and which has a presser foot with upper and lower through holes at its tip; A swing arm that moves along the movement direction in synchronization with the lower feed dog that moves back and forth, a support member that is rotatably and movably locked up and down at the base end of the presser arm, and a tip end. The upper feed of the sewing machine consists of a feed arm, which has an upper feed dog that loosely fits into the upper and lower through holes of the presser foot, and whose base end is supported on a support member so that the upper feed dog moves four times in conjunction with the swing arm. mechanism.