GB707815A - Improvements in or relating to power presses - Google Patents

Abstract

707,815. Toggle presses. PARSONS, A. T. April 4, 1952 [Jan. 10, 1951], No. 734/51. Class 87 (2) In a power press in which a reciprocating press head is connected by toggle links to a fixed part of the press and to a valve-controlled fluidoperated piston and cylinder disposed at rightangles to the toggle links and adapted to extend and contract them, the piston rod 8 of the operating cylinder is associated with the press frame (at 6) and press head 1 by a set of short toggle links 7, 13 and the operating cylinder 10 is associated with the press frame and press head by a set of longer toggle links 9, 14. The front end of the cylinder 10 is thus suspended by the links 9, 14; its rear end is suspended by links 17 from a pin 19 which is engaged in arcuate slots 20 in the side plates 4 of the frame and held in position by nut carrying a handle 22. To adjust the working stroke the height of the upper toggle links axis pin is altered by screws 25, 26 passing through a cross-bar 6 of the frame, 'the pin 19 then being altered to the same level by moving it in the slots 20 with the nut slacked off. As the piston rod 8 is forced by fluid pressure out of the cylinder 10, i.e. to the left as in Fig. 3, the toggle links 7, 13 first straighten and thus give a second stamp (the first having been given when the Piston rod moved into the cylinder) and then, after passing through dead-centre, raise the press head 1. At the same time the cylinder 10 moves in the opposite direction to the piston and thus collapses the toggle links 9, 14 (which can never straighten although the links 7, 13 can), thereby assisting in raising the press head, which is guided by rods 2 running in bearings in the side plates 4. The valve gear 28, which may be in any convenient position, controlling the inlet and exhaust of fluid to and from the operating cylinder, may be interlocked with the press guard so that operation of the press depends on the position of the guard. Instead of suspending the rear end of the cylinder 10 by links 17 it' may be supported by long links associated with the upper and lower toggle link axis pins.