Swing throw crank structure

Claim 1

An improved swing throw crank structure in combination with an internal combustion engine that includes a piston, a cylinder in which said piston reciprocates, a piston rod pivotally connected to said piston, said piston rod including a journal, and a drive shaft rotatably supported in a fixed position relative to said cylinder for transforming reciprocating movement of said piston to rotary motion of said drive shaft, said swing throw crank structure including: a. first and second parallel, laterally spaced rotor plates that are co-axially aligned, said first rotor plate having an arcuate slot extending within a side surface thereof most adjacent said second rotor plate, said second rotor plate having an arcuate opening therein transversely aligned with said slot, said first rotor plate secured to said drive shaft, said slot and opening each partially defined by a force receiving edge of said first and second rotor plates; b. first means for maintaining said first and second rotor plates in fixed laterally spaced relationship; c. a force transmitting assembly at least partially disposed between said first and second rotor plates that include an elongate rigid body that has first and second end portions, a first arcuate force transmitting member projecting rearwardly from said body that slidably engages said slot, a second arcuate force transmitting member that projects forwardly from said body and slidably engages said opening, and first and second transversely spaced cam rollers rotatably supported from said first and second end portions of said body; d. a stub shaft that extends outwardly from said second force transmitting member and is rotatably engaged by said journal of said connecting rod; and e. first and second generally elliptical, transversely spaced, cam surface defining means that are at all times engaged by said first and second cam rollers and are so related to said force transmitting assembly that a power stroke only starts as said piston moves through top dead center and said second force transmitting member and the portion of said force receiving edge of said opening in contact therewith have moved to a position substantially to one side of the axis of rotation of said first and second rotor plates and continues to be so disposed until substantially bottom dead center on the power stroke is reached to substantially increase the torque delivered to said drive shaft in the rotation thereof over that attained when a conventional crank is employed to rotate a drive shaft.