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:
Aug. 10, 1993
Filed:
Sep. 13, 1991
Stephen L Bellio, West Roxbury, MA (US);
The Charles Stark Draper Laboratory, Inc., Cambridge, MA (US);
Abstract
Apparatus and method for detecting skipped stitches for chainstitch sewing machines having a looper assembly using a needle thread movement sensor and/or a looper thread movement sensor in combination with a shaft rotation sensor. Needle thread movement is correlated with needle shaft rotation per stitch cycle to detect instances when there is no needle thread movement during a stitch cycle. Similarly, looper thread movement may be correlated with needle shaft rotation per stitch cycle to detect instances when there is no looper thread movement during a stitch cycle. The invention includes methods for detecting needle loop and triangle skips by detecting instances of substantially no needle thread or looper thread movement during certain respective portions of the stitch cycle.