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:
Jul. 31, 1979
Filed:
Apr. 25, 1978
Donald J Coughenour, Morristown, NJ (US);
Jack Brown, Union, NJ (US);
John A Herr, Garwood, NJ (US);
The Singer Company, New York, NY (US);
Abstract
A mechanism for detecting the depletion of bobbin thread in a sewing machine. A bobbin is formed with a polygonal core having a plurality of light reflecting surfaces contained thereon. A light source transmits a beam of light toward the polygonal core of the bobbin and the light reflected therefrom is intercepted by a photodetector. The polygonal reflecting surfaces contained on the bobbin core do not begin to reflect light until a sufficient quantity of bobbin thread has been consumed in the sewing process to expose a part of the reflective surface portion of the bobbin core. The rotation of the bobbin thereafter results in flashes of light being received by the photodetector. An electronic circuit analyzes the output of the photodetector and distinguishes between the flashes and steady ambient light to signal the impending depletion of bobbin thread.