NEEDLE THREAD BREAKAGE DETECTOR OF SEWING MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a needle thread breakage detector of a sewing machine which obviates the deterioration in accuracy by dirt of dust and oil. SOLUTION: A magnet 1 is mounted via a magnet case 10 to one end 31 of a thread take-up spring 3. A magnetic sensor 4 is disposed to face this magnet 1. The position of the magnetic sensor 2 is so determined that the sensor turns on when the magnet 1 exists in a thread tightening position and turns off when the magnet exists in an open position.