Drive mechanism for dough shaping apparatus

In apparatus for forming french fry shaped bodies from potato dough of the type in which dough is moved through the spaces between a plurality of parallelly spaced elongate members so as to form protruding dough pieces that protrude by a distance corresponding to the width of a french fry shaped piece and wherein a cutter wire is reciprocated across the protruding dough to sever the protruding dough pieces from the dough on the opposite side of the elongate members, the improvement comprising a piston for moving the dough toward said elongate members, an elongate rod secured to said piston, a plurality of uniformly spaced apart slots in said rod, each said slot having a concave cylindric surface extending transversely and chordally of said rod, the interval between adjacent slots being approximately equal to the width of a french fry shaped potato piece, a crank arm and means for supporting said crank arm for pivotal movement above a fixed pivot axis perpendicular to and spaced from said rod, said crank arm having a distal end spaced from said rod by an increment so that said distal end is intermediate said pivot axis and said rod, a yoke having a first end pivotally supported at said distal end and a free end spaced from the distal end by a distance greater than the increment, a cross pin mounted at said free end and extending in parallelism to said pivot axis and engagable with said notches, said cross pin being of cylindric shape and having a radius substantially equal to that of said notch surface so as to contact said notch surface over a substantial surface area, means for biasing said yoke relative said crank arm to effect engagement of said cross pin with the notches in said shaft, means for rocking said crank arm in an arc less than 360.degree. to produce a power stroke so that said cross pin moves said rod and said piston toward the spaced apart elongate members, said distal end describing an arcuate path during said power stroke so that said crank arm and said yoke pass through a dead center position during said power stroke, said cross pin, said distal end and said pivot axis residing in coplanar relation at said dead center position so that further pivotal movement of said crank does not effect further movement of said rod and said piston, and means linked to said rocker arm for reciprocating said cutter wire, said reciprocating means acting to reciprocate said wire cutter only after said dead center position.