| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to surely detect the presence or absence of a thread with substantially no influence of the slack of the thread and further to easily set the thread to a thread presence or absence detector as the thread presence or absence detector of a sewing machine. SOLUTION: The thread presence or absence detector for detecting the presence or absence of the needle thread A of the sewing machine has a light emitting section 12, a light receiving part 14 for receiving the light from this light emitting part 12 and a thread guide member 10 having slender thread guide grooves 17 and 27 penetrating the top of the optical path connecting the light emitting part 12 and the light receiving part 14 in a direction intersecting across the prescribed length. The needle thread A is passed into these thread guide grooves 17 and 27 and the change in the photodetecting quantity accompanying the presence or absence of the needle thread A in the thread guide grooves 17 and 27 is detected, by which the presence or absence of the needle thread is detected. The thread guide member 10 has apertures 16 and 26 for thread insertion which are bent and are communicated with the thread guide grooves 17 and 27 and open outward.
|
