Drive mechanism for a sewing machine puller wheel

Claim 1

A puller wheel drive mechanism for use in association with a sewing machine having a pedestal provided with a horizontally projecting arm spaced above a work surface sufficiently to allow unobstructed movement beneath said arm of material being sewed, said arm supporting a reciprocable needle and presser foot assembly at a distance from the pedestal and a horizontal main shaft connected with a motor to drive said needle assembly, said drive mechanism comprising: (a) a variable speed gearbox positioned behind said pedestal having an input shaft, an output shaft, and external control means to vary the rotational speed of the output shaft with respect to the rotational speed of the input shaft; (b) toothed endless belt and pulley means drivingly connecting said input shaft to said main shaft; an idler puller wheel rotatably mounted at the level of said work surface and behind said reciprocable needle assembly; (d) a yoke assembly having a driven puller wheel disposed above said idelr puller wheel; (e) second drive means drivingly connecting said output shaft to said driven puller wheel comprising horizontal flexible shaft means connected at one end with said output shaft of the gearbox and supported at the other end by said yoke assembly at a distance above said work surface sufficiently to allow unobstructed movement of sewed material beneath said shaft, and toothed endless belt and pulley means drivingly connecting said driven puller wheel with the other end of said shaft and (f) pneumatic means to raise and lower said yoke assembly including said driven puller wheel independently of said reciprocable presser foot assembly.