GB539160A - Improvements relating to hydraulic presses - Google Patents

Abstract

539,160. Embossing machines. TURNER TANNING MACHINERY CO., Ltd., and SCHETTLER, G. A. Feb. 28, 1940, No. 3731. [Class 100 (ii)] [Also in Group XXIX] A hydraulic press such as is used for smooth plating or embossing leather of the kind in which the main ram 2 is operated to close on the work by an auxiliary ram 4 working in an auxiliary cylinder 3 is constructed with a byepass valve 16 for opening up connection between the two cylinders when high-pressure liquid is admitted to the cylinder 1 through a pipe 12 which is preferably fitted with a valve device as described in Specification 539,159, [Group XXIX]. The valve 16 is attached to a spring-pressed plunger 15 which slides in a cylinder 14 arranged in a stepped recess in the main, ram 2, a sleeve 17 being also secured to the recess by means of 'bolts 20 which also secure the cylinder 14 in place. The sleeve 17 is formed with ports 21 which are normally closed by the valve 16 which remains closed during the initial upward movement of the ram 4. A washer 28 ensures a watertight engagement of the ram 4 with the sleeve 17, and the spring 23 keeps the valve 16 closed during this initial movement. When the main pressure is put on, the plunger 15 is raised by the fluid pressure and the valve moves to the position indicated in Fig. 3 thus opening up connection between the cylinders 1, 3. The recess in which the spring 23 is arranged is fitted with a vent passage 24, and the ram is fitted with spring buffers 9. A sealing ring 25 of soft copper makes a tight joint with the upper ends of the cylinder 14 and the plunger 15 when in its raised position Fig. 3. A vent passage 29 may be provided to assist retraction. The press is adapted to deal readily with work of various thicknesses.