GB866989A - Improvements in or relating to machine presses - Google Patents

Abstract

866,989. Angular bending ; shearing. CHARLES, S. W., GRIGG Ltd., and STEVENS, A. T. W. Feb. 18, 1959 [Feb. 18, 1958], No. 5303/58. Class 83 (4). A press brake or guillotine shear having a beam moved to and from a bed by two main fluid-pressure cylinders, one at or near each end of the beam and valve means for controlling fluid supply to the pressure cylinders is characterized in that the valve means is controlled by transmission members, e.g. chains, connected one to each end of the beam, so that the ends of the beam have equal movement. A beam 2 formed with a longitudinal bending edge 6 is moved down towards a bed 1 formed with a longitudinal groove 5 to bend sheet-metal between the edge and the groove, by hydraulic cylinders 8 disposed one at each end of the beam 2. To ensure that ends of the beam 2 are moved equal amounts, valve means 9 controlling fluid flow to the cylinders 8 is in turn controlled as follows : A chain 13 is adjustably secured at one end at 26 to one end of the beam 2 and passes over a sprocket 47 on a press frame member 3a, and over a pinion 43, formed on a wheel 15, to a compressed air cylinder 18. Another chain 14 secured to the other end of the beam 2 and to cylinder means 18, at the same pressure as the other cylinder 18, likewise passes over pinions 42, 44 formed on the wheel 15, the chain 14 dividing into two parallel runs at this point. The wheel 15 is loose on a shaft 19 mounted on a carriage 16 slidable in guides 17 in the press frame 3a. If the ends of the beam 2 move equally the wheel 15 merely rotates on the shaft 19 but if one end should move more than the other the carriage 16 moves to rock, through links 20, bell-cranks 21 to actuate the valve associated with the appropriate cylinder 8. Arms 27 on the shaft 19 operate switches 30 to stop the machine on excessive unequal movement of the beam ends. The beam 2 may be set at an angle to the bed 1. In a modification, Fig. 8, the shaft 19 is carried by a pivoted lever 72, the upper end of which engages a roller 78 on the bell-crank 21 to actuate the valve means 9. Alternatively, Fig. 10 (not shown), the lever 72 may be connected by a link to the bell-crank 21. The stoparms 27 are carried by the pivoted lever. Straight parts of the chains 13, 14 may be replaced by rods. Only one chain may be adjustable on the beam 2. Each chain may be connected to the wheel 15 by a pin and the part of the chain extending from the cylinder 18 connected to the wheel 15 by a diametricallyopposite pin. The machine may be arranged so that the beam moves horizontally or at an angle instead of vertically.