APPARATUS AND METHOD FOR DETECTING REMAINING THREAD OF A SEWINGMACHINE

摘要

The present invention relates to an apparatus and a method for checking a remaining lower thread length around a lower thread bobbin during a sewing machine operation. According to the present invention, a sewing operation is performed with a predetermined amount of lower thread required for the sewing operation wound around the lower thread bobbin. In the case of sewing machines in general, a stitch length per needle set by a lever in the sewing machine during an operation is calculated in the rotation speed of the sewing machine so that a user can be aware of a lower thread consumption amount and the degree of consumption. In a computer design-accommodating sewing machine, stitch length per needle and stitch number information is checked in advance by means of sewing design so that the lower thread can be wound and used in accordance with an operation amount As the operation is in progress, the lower thread is calculated in the rotation speed of the sewing machine so that a user can be aware of a lower thread consumption amount and the degree of consumption in advance. The general sewing machine stitch length setting device according to the present invention includes: a cylindrical stitch length setting lever and setting a stitch length per needle; a wheel rotating in response to a vertical movement of an upper thread needle and having a slit formed on an outside circumference; a wheel rotation detection sensor emitting light to the slit formed in the wheel and measuring the pulse amount of an optical signal received after being reflected among the emitted beams; and a control unit calculating a lower thread consumption length from the stitch length per needle set by the stitch length setting lever and the rotation speed of the wheel calculated based on the information provided from the wheel rotation sensor. The sewing design-accommodating computer sewing machine refers to previously sewing-designed design and performs use and setting with reference to the data.