Type synthesis of single-DOF single-loop mechanisms with two operation modes

A single-DOF single-loop mechanism with two operation modes is a single-DOF single-loop mechanism which works as two different single-DOF single-loop mechanisms each in one of its two operation modes. It is also called a discontinuously movable mechanism or kinematotropic mechanism. This paper deals with the type synthesis of single-DOF single-loop mechanisms with two operation modes. An intuitive approach is proposed to the type synthesis of this class of mechanisms at first. Using the proposed approach, single-DOF single-loop mechanisms with two operation modes are then constructed using planar 4R, Spherical 4R, Bennett 4R mechanisms and/or paradoxical 5R- and 6R- mechanisms. In addition to the two classes of 7R single-DOF single-loop mechanisms with two operation modes proposed in the literature, 16 new classes of 6R and 7R mechanisms are proposed.