Patent ID: 7793602

Claim:
A machine for stitching at least one fabric layer, said machine comprising: an upper arm and a lower arm mounted in vertically spaced substantially parallel relationship to define a throat space therebetween; a substantially horizontally oriented plate mounted proximate to said lower arm for supporting said fabric layer for guided movement in said throat space; a needle arm supported from said upper arm actuatable to reciprocally move a needle substantially perpendicular to said plate for piercing said fabric layer with a top thread paid out from a top thread supply source; means for paying out a bottom thread from a bottom thread supply source for forming a lock stitch with said top thread each time said fabric layer is pierced by said needle; guide means for guiding one of said threads for longitudinal movement along a defined path; detector means including an optical sensor mounted proximate to said path for producing an output signal representative of longitudinal thread movement along said path; and control means responsive to said output signal for actuating said needle arm at a rate related to the rate of longitudinal thread movement along said path.