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:
Nov. 15, 1994
Filed:
Dec. 15, 1992
Abstract
A thread tensioning device comprising a stationary electromagnet mounted on a sewing machine arm and a tensioning wheel having a relatively low mass. The tensioning wheel is rotatable concentric to a longitudinal axis of the electromagnet and is mounted on the electromagnet so as to be moveable only slightly in the direction of the longitudinal axis. A friction disk is positioned at one end of the electromagnet so as to be between the electromagnet and the tensioning wheel. A current flows through an excitation winding in the electromagnet and its value is varied within given limits by a suitable current control device, thereby causing the electromagnet to pull a flat side of the tensioning wheel with corresponding force against an application side of the friction disk, whereby a corresponding variable thread tensioning force is applied to a sewing thread passing through the tensioning wheel to the sewing machine.