IMPROVEMENTS IN OR RELATING TO A HYDRAULIC DEVICE FOR DRIVING THE PRESSING ELEMENT OF A PRESS OR THE LIKE

摘要

1291092 Shearing; stamping; press brakes V L A BIANCHI 19 Dec 1968 [27 Dec 1968] 62055/69 Headings B3E B3Q and B3W [Also in Division B5] A press, shear or the like comprises a plurality of double-acting piston-cylinder devices la, 1b, 1c, 1d which are hydraulically connected in series so that the rear chamber, e.g. 5a of one actuator is connected by a flow line to the front chamber 4b of the next, and a make-up fluid tank 18 connected through a valve 15, 16 or 17 to each flow line to supply liquid thereto, and operating means controlled by an actuator and adapted to open the valve when the actuators reach a stroke-end position. The invention ensures that a pressing &c. element 7 to which the actuators 1a ... 1d are connected moves parallel to a stationary element (41), Fig. 2 (not shown). The valves 15, 16, 17 are operated by a solenoid valve 20 connected in circuit with a switch 23 which is closed by an arm 24 when piston 2b reaches the end of its stroke. The stroke of each piston can be adjusted by means of a threaded rod, as 25b, received in a threaded sleeve, as 26b, rigidly connected to its piston 2b. The threaded rods are rotatable together by means of an electric or hydraulic motor 30 through sprockets and chains (see Fig. 3, not shown).