Brother Kogyo Kabushiki-Kaisha

Yoshikazu Yamamoto

Toshiaki Yanagi

Shiro Yamada

Akira Sugiyama

Kunio Haneda

Kohzoh Sano

A sewing machine in which the start and stop of a main shaft is controlled by a cam mechanism through a motion control mechanism at the sewing cycle corresponding to a predetermined number of stitches. The working position of a work holder is controlled by positional data in original instructions stored in a memory. Additional instruction corresponding to the number of stitches to reach the next stop time point controlled by the cam mechanism is prepared for back-tacking, unless the number of stitches corresponding to the original instructions are equal to an integral multiple of the predetermined number of stitches.

Cyclic sewing machine

An automatic sewing machine provided with a memory for storing stitch instructions directing a relative position between a vertically reciprocated needle and a work piece and a speed control means for controlling the machine's drive motor at a suitable speed for each particular sewing operation carried out according to the stitch instructions. To determine the maximum permissible speed suitable to the variation of the relative position for each stitch, all of the stitch instructions in the memory are checked by a central processing unit before starting each sewing operation. The unit provides a control signal concerning the maximum permissible speed to a speed control means so that the driving speed of the drive motor is limited to no more than the maximum permissible speed.

Automatic sewing machine

An automatic sewing machine having an improved drive speed control system. Many stitch instructions each indicating the relative position between a vertically reciprocated needle and a workpiece are stored in a memory in a predetermined sequence. The large number of stitch instructions are divided into a plurality of groups consisting of a predetermined number of consecutive stitch instructions. For each group, a maximum permissible speed is determined in accordance with the variations of the relative position between the needle and the workpiece directed by the instructions of the group. This maximum permissible speed causes formation of an exact stitch pattern in the workpiece according to the stitch instructions in each of the groups. A speed control device controls the speed of the drive motor in accordance with the various maximum permissible speeds. This causes sewing to be performed in a highly effective and exact manner.

This invention relates to a contour tracing sewing machine for forming a line of seam on a workpiece in conformity with a contour of a stitching templet of a desired shape. The tracing device used in the contour tracing sewing machine comprises a light source for emitting light towards the stitching templet, and a light sensing head consisting of a plurality of optical fibers arranged in an annular form for transmitting the light radiated on the stitching templet to a plurality of photoelectric cells. The tracing device further comprises a device for selecting a predetermined tracing direction according to electric signals produced from the plurality of photoelectric cells, so that the stitching templet and the workpiece may be shifted relatively to the light source and the sensing head by a drive device of an open-loop type in the tracing direction thus selected.

Growing community of inventors

Nagoya, Japan

Yoshikazu Yamamoto