Interconnecting rotary and reciprocating motion

Apparatus for converting reciprocating motion to rotary motion and vice-versa comprising a reciprocatory assembly guided for reciprocation in a first direction and comprising first and second reciprocating members each terminating in a planar guide surface transverse to the direction of reciprocation, and spacing tie means interconnecting the two reciprocatory members to maintain the guide surfaces parallel, spaced apart and facing each other, a drive block having opposed guide faces each slidably engaged with a respective one of the guide surfaces of the reciprocatory members for travel therealong, and a rotary member mounted for rotation about an axis transverse to the direction of reciprocation and having an eccentric portion rotatably engaged in the drive block, and spacing tie means comprising two pairs of side plates, said pairs being associated respectively one with each end of said guide surfaces, each said side plate having a reentrant providing clearance for said eccentric portion of the rotary member during movement of said rotary member relative to said reciprocating members, securing means securing portions of each said side plate on opposite sides of said reentrant respectively to said reciprocatory members at intervals along said side plate portions, said side plate portions and said reciprocatory members having load-transmitting interfitting depressed and protruding formations therealong.