THEORY OF SYMMETRICAL MECHANISMS

The paper deals with double crank linkages with symmetrical properties. Concepts like coordinate, kinematic, mass and force symmetries are strictly defined, and input motions providing equal kinematic status of the cranks are specifically discussed. An infinite number of symmetrical motions are shown to exist, and appropriate procedures to derive such motions are developed. A similar analysis is presented to cover the force symmetry problem, and a scheme for equivalent power distribution between the cranks is offered. Numerical analyses of sample linkages shows that considerable improvement in the dynamic performance is possible if the theory is followed. © 1990.