The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 25, 1982
Filed:
May. 23, 1980
Susumu Hanyu, Hachioji, JP;
Yoshinobu Tonomura, Hachioji, JP;
Hideaki Takenoya, Hachioji, JP;
Masanori Hara, Hachioji, JP;
Janome Sewing Machine Co., Ltd., Tokyo, JP;
Abstract
A device for automatically adjusting the tension of a lower thread, which comprises a lower thread bobbin arranged on a bottom plate of a bobbin carrier turnably carrying the bobbin, a loop taker mounted on a magnetic shaft, and an energizing coil arranged around the magnetic shaft and providing together with said bottom plate and magnetic shaft a path of magnetic flux. The device is further provided with a detector detecting the consumed amount of the bobbin thread and a control circuit for energizing the coil when the lower thread is wound to the maximum capacity of the bobbin, interrupting the light of the detector. The detector operates the control circuit to decrease the amount of electric current applied to the energizing coil so as to set the lower thread tension back to its initial predetermined value.