Sewing machine

Abstract

The invention relates to the technical field of cloth sewing, in particular to a sewing machine. The machine comprises a motor, a thread trimming cam, a thread trimming driving crank and a thread trimming mechanism, the motor drives the thread trimming cam to rotate forwards or backwards, and the thread trimming cam is provided with a thread trimming driving profile surface and a first reset driving profile surface. One end of the thread trimming driving crank is provided with a thread trimming roller matched with the thread trimming driving profile surface and a first reset pin matched with the first reset driving profile surface, and the other end of the thread trimming driving crank is connected with the thread trimming mechanism; and when the thread trimming cam rotates forwards, the thread trimming drive profile surface can act on the thread trimming roller to drive the thread trimming drive crank to move so as to drive the thread trimming mechanism to execute the thread trimmingaction, and the first reset driving profile surface acts on the first reset pin to drive the thread trimming drive crank to move reversely after the thread trimming action is completed so as to drivethe thread trimming mechanism to execute the reset action. The thread trimming action and the reset action of the thread trimming mechanism after thread trimming can be completed in the whole-circle rotation process of the motor, and the motor does not need to be suddenly stopped or suddenly started for steering.

Description

technical field [0001] The invention relates to the technical field of cloth sewing, in particular to a sewing machine. Background technique [0002] In the existing sewing machine, the thread trimming mechanism is driven by a stepping motor to perform the thread trimming action, and its drive control logic sequence is thread trimming, and then reverse reset. In the process of completing the thread trimming action, when the motor rotates from the initial zero position to the maximum thread trimming moment, after driving the thread trimming mechanism to complete the thread trimming action, it needs to be reversed and reset to the initial zero position to reset the thread trimming mechanism. During the execution of such control logic, the motor needs to be stopped and started quickly to realize the steering. The motor needs to be started and stopped twice in one cycle, and there is a problem of slow response to the thread trimming action. For the structure where a stepping mo...

AI Technical Summary

Problems solved by technology

For the structure where a stepping motor simultaneously drives the thread trimming mechanism and the presser foot lifting mechanism to realize the thread trimming function and the presser foot lifting function respectively, when performing the action of lifting the presser foot after thread trimming, the motor needs to rotate from the initial zero position to the maximum At the moment of thread trimming, drive the thread trimming mechanism to complete the thread trimming action, then reverse and reset to the initial zero position to reset the thread trimming mechanism, and then continue to reversely drive the presser foot lifting mechanism to perform the presser foot lifting action. Sudden stop and start of steering will result in a long cycle of action and slow response of presser foot lifter

In the above two structures, although the time period can be shortened by increasing the motor speed, this will increase the load on the motor, which is not conducive to the service life of the motor

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