Self compensating optoelectronic ply and edge detector for sewing machine
AssigneeThe Singer Company
InventorEugene A. Sansone
Life of this patent
Estimating the term…
Abstract
A light sensing device for a sewing machine with a sensing circuit which automatically compensates for the work fabric being utilized so as to be able to detect a ply change event in any fabric without requiring an operator adjustment for the type of fabric being stitched upon. Being able to detect a ply change event without the necessity for adjustment also permits automatic operation of certain sewing machine components, further facilitating operation of the sewing machine.
Claims12
A self compensating fabric ply and edge detector for a sewing machine having a frame including a work supporting bed, said frame supporting a needle bar for endwise reciprocation, a sewing needle fastened to one end of said needle bar, a throat plate, a needle accommodating orifice extending through said throat plate, a loop taker supported beneath said throat plate for cooperation with said sewing needle extending through said needle accommodating orifice in the formation of stitches, means for feeding a work fabric through said sewing machine beneath said sewing needle, said fabric ply and edge detector comprising:
- a light sensing device, means for supporting said light sensing device in said work supporting bed before said needle accommodating orifice in the direction of feed of said work fabric, a source of light for said light sensing device, means for establishing a DC level related to average light reaching said light sensing device, means for passing an AC component of a change in incident light reaching said light sensing device, means for variably diverting current in response to said AC component from said passing means, means for supplying current related to said average light for diversion by said diverting means, and means for initiating a selected response on diversion of current by said diverting means substantially greater than that related to said average light.
A self compensating fabric ply and edge detector for a sewing machine having a frame including a work supporting bed, said frame supporting a needle bar for endwise reciprocation, a sewing needle fastened to one end of said needle bar, a throat plate, a needle accommodating orifice extending through said throat plate, a loop taker supported beneath said throat plate for cooperation with said sewing needle extending through said needle accommodating orifice in the formation of stitches, means for feeding a work fabric through said sewing machine beneath said sewing needle, a presser foot, means for selectively supporting said presser foot in and out of engagement with said work fabric and feeding means, said fabric ply and edge detector comprising a light sensing device, means for supporting said light sensing device in said work supporting bed before said needle accommodating orifice in the direction of feed of said work fabric, a source of light for said light sensing device, means for passing an AC component derived from a change in incident light reaching said light sensing device, a power source, means biased for normally diverting current from said power source but responsive to a decreasing voltage excursion from said passing means for not diverting current from said power source, and means responsive to the duration of said decreasing voltage excursion for initiating a selected response.
Dependencies are inferred from the claim text.