GB775694A - Improvements in or relating to liquid pressure operated presses - Google Patents

Abstract

775,694. Hydraulic presses. HARE, Ltd., P. J., and HARE, P. J. Nov. 24, 1955 [Oct. 12, 1954], No. 29384/54. Class 69 (2). [Also in Group XXIV] An hydraulic press for light work has the press ram brought into contact with the work by a spring. A pump 18 is disposed in a reservoir 17 and supplies liquid through a valve 23 to a press cylinder 15 above or below a ram 16, therein to apply the working pressure to the ram or to retract it. A spring 35 brings the rani rapidly into contact with the work, liquid additional to that supplied by the pump being drawn from the reservoir 17 through a conduit 41 and non-return valve 42. The ram 16 is guided in an extension 25 of the lower wall of the reservoir, and the stroke is limited by the contact of an adjustable nut 49 with this extension. A plate 56 is clamped to the lower end of the ram, is guided between pillars 12, and carries a yoke 57 having pins 58 engaging the upper sides of a pair of links 59 which are pivoted at one end to the press frame and at the other end to a vertically movable guard 61. A second pair of links 62 connect the guard to a shaft 63 which carries an arm 64 contacting a plunger 65 of the valve 23. When the guard 61 is pulled down, the last part of the movement depresses the plunger 65, thus connecting the upper end of the ram cylinder to the pump and the lower end to the reservoir. The ram is thus moved into engagement with the work by the spring 35, the pressure then building up to the working value determined by a relief valve 44. When the working stroke is completed the guard is lifted manually, the initial part of the movement allowing the plunger 65 to rise, changing over the valve 23 and causing liquid to be admitted to the lower end of the cylinder 15 to raise the ram.