Abstract: A connecting rod for reciprocally driving a piston within a cylinder wherein the piston rod includes upper and lower portions which are connected by an area of thinner dimension which is also yieldable so as to permit the lower end of the connecting rod to assume varying angular orientations with respect to the upper end thereof and wherein the lower end of the rod includes a bearing surface which is cooperatively received so as to be driven by the end of an operating lever by way of which motion is imparted to the connecting rod.