JPS5556938A - Cloth feeder - Google Patents

Abstract

PURPOSE: To prevent the occurence of a phase difference between a cloth feeding motion and a needle reciprocating movement, which are performed by rotary mechanism, and a cloth feeding motion performed by a feeding gear, by obtaining driving pulses for a step motor running in synchronism with the rotation of a main shaft at an industrial sewing machine.

CONSTITUTION: As a result of a given number of discs 57 being rotated against a disc 55, a given number of slits 56 are covered with shielding strips 58 so that a pulse equivalent to one cloth feeding cycle, i.e., a cloth feeding amount required for each rotation of a sewing machine main shaft 59 can be obtained. Thus, starting and driving characteristics being most suitable to a step motor 5 should be obtained. As a result of respective mechanisms being driven, the discs 55 and 57 are also rotated, a series of pulses generated on the basis of the slits not shielded being supplied from a light receiving element 54 to a drive circuit 63. An output shaft of the motor 5 is then rotated in stages, a roller 47 being also rotated through the medium of a pulley 7, a belt 13, and a pulley 17a. Simultaneously, the cloth is displaced by means of a feeding mechanism comprising feed teeth 21 or the like, and thus, the cloth nipped between the roller 47 and a stand 1 is displaced backward.

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