GB437913A - Improvements in portable punching and riveting presses - Google Patents

Abstract

437,913. Hydraulic presses. FORICHON, G. S., 3, Rue de Strasbourg, Asnieres, Seine, France. Nov. 2, 1934, Nos. 31549 and 31550. Convention dates, Nov. 2, 1933 and Oct. 17, 1934. [Class 69 (ii)] [See also Group XXII] In a punch or riveting press, wherein the movable head is actuated through a liquid of constant volume and is moved up to the work by a low-power piston, whereupon the working stroke is effected by a high-power piston, the movable head and the two pistons are disposed coaxially, to form an easily transportable assembly. A press for riveting or punching comprises a movable ram 1 engaging within a cylinder 4 which is in screw-threaded engagement with a cylinder 5. The approach movement of the ram is effected by a piston 2 causing liquid to pass from cylinder 5 into cylinder 4 through orifices 10. The plunger of a piston 3 then closes the orifices 10 and enters the bore 9 of the ram, after sealing the cylinder 4 at the joint 8 to effect the riveting or punching operation at high pressure. Escape of fluid is prevented during the complete cycle of operations by two high pressure joints 8, 40, arranged between two low pressure joints 6, 1<2>. The admission of pressure fluid behind the piston 3 initially occurs through restricted passages 3<2>, 3<3>, the rapid movement of the piston occurring only when a projection 3<1> has cleared the inlet 18<1>. The initial position of the piston 2, and therefore of the ram 1, is controlled by a handle 26 in screw-threaded engagement with a projection 2<1> on the piston. The valve controlling the admission of fluid to the pistons 2, 3 is operated by a lever 12. A modified form is described wherein a pipe provides constant communication between the chamber 5<2> of the cylinder 5, and the chamber housing the spring 24.