This mechanism is as well, a modification of the conventional four-bar mechanism in a way that, both links except the coupler are extended to meet at a point, on which two sliders are placed and connected with a revolute joint to each other. Each slider moves respectively on one of the links through guideways or a prismatic joint. Hence the system has in all five bodies namely two links one coupler and two sliders; and seven planar joints, namely five revolute joints and two prismatic joints, and therefore it has only one degree of freedom.