Patent ID: 6729252
Filing Date: 2004-05-04
Classification: D05B,D05D

Abstract:
A thread device for a sewing machine, comprising:a spool mounting member which rotatably supports a thread spool wound with thread to be fed to a needle of the sewing machine and is attached to a machine body of the sewing machine; a thread winding mechanism which is connected to the thread spool and feeds backward the thread, being fed from the thread spool to a needle side, to the thread spool; a feed mechanism which is disposed on a thread path between the thread winding mechanism and the needle of the sewing machine and performs an operation feeding the thread of the thread spool to the needle side and an operation feeding the thread in the needle side to a side of the thread winding mechanism; a thread detecting mechanism which is disposed between the feed mechanism and the thread winding mechanism and generates a first detecting signal when detecting the thread in a tense state; a feed-backward amount detecting mechanism which generates a second detecting signal when an amount of the thread fed backward to the thread spool by the thread winding mechanism reaches a given value; and a controller which feeds a given amount of the thread to the side of the thread winding mechanism by operating the feed mechanism when the first detecting signal is generated by the thread detecting mechanism, repeats a feed-backward operation in which the given amount of the thread is fed backward by the thread winding mechanism after feeding the given amount of the thread, and stops winding when the second detecting signal is generated by the feed-backward amount detecting mechanism.