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:
Feb. 17, 1981
Filed:
Mar. 01, 1979
Toshibumi Kamiyama, Kadoma, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A sewing machine having a rotary hook shaft, a bobbin case with a hollow cylindrical shaft journalled through the rotary hook shaft, and a bobbin rotatably mounted on the shaft of the bobbin case. An axially spring-biased cylindrical member is provided for unitary rotation with the bobbin and axially movable between a first position in which it is held against the lateral edges of the thread layers when the latter is present through the length of the cylinder of the bobbin and a second position in which the thread layers have reduced to a predetermined radial extent. A detector is provided to sense the axial movement of the spring-biased cylinder member from the first to second positions.