PURPOSE: To obtain an internal force utilizing engine, by forming a cylinder and a main body in a unitary manner, connecting a piston and a piston rod by a piston pin, and connecting pressure receiving plates and the main body and connecting the pressure receiving plates and the piston rod respectively by pins.

CONSTITUTION: A piston 3 and a piston rod 4 are connected by a piston pin 5, and pressure receiving plates 7 and a main body 6 are connected together by means of pins 8, 10, 11. Further, a cylinder 1 and the main body 6 are formed in a unitary manner by connecting the plates 7 and the piston rod 4 by reaction pins 9. When a force F1 is applied to the piston 3 by an article 13, it is divided at the piston pin 5 into component forces F2 and F3. The component force F2 is acted to the pressure receiving plates 7 via reaction pins 9, so that the plates 7 are rotated together with the main body pivoting about pins 10, 11. On the other hand, when a force F4 is applied to the cylinder 1 by the article 13, the entire body is rotated pivoting around pins 10, 11. Further, if forces F1 and F4 are applied simultaneously, it works in the direction in which the resultant force of F3 and F6 is acted.