GB922933A - Improvements in or relating to guillotines and press brakes - Google Patents

Abstract

922,933. Shearing; press-brakes. STEEL CONSTRUCTION & ENGINEERING CO. (NOTTS) Ltd. Jan. 5, 1961 [Jan. 6, 1960], No. 415/60. Class 83 (4). [Also in Group XXIV] A guillotine or press brake comprises two or more toggle linkages 65, 72 for converting movements of an hydraulically operated rod 44 into downward movements of the upper blade, or bending-bar, carrier 14, and intermediate links 73 connecting the toggle linkage to the pressframe. This comprises side plates 1, on upper box beam 9, and a lower box structure 2, forming a table with a slotted edge member 33 for an extension 34 on which work may be secured by clamps 35. Balls 43 recessed into the table facilitate movement of the work. A plate 22A deflects severed stock to the rear of the guillotine, and an adjustable work-stop 100 is carried by arms 101. The toggle linkages are located between a back plate 3 and a removable front plate 5 which is secured by plates 26 and spigots 28 to the beam 9 and by bolts 8 to the side plate 1. The lower blade 40 is secured to the table by bolts 42 and adjusted by further bolts, Fig. 6 (not shown). Hydraulic cylinders 94 for a hold-down bar 31 are mounted on the plate 5, and a guard 99 is advanced towards the operator by bell-crank levers 97 on depression of the starting treadle 95. The rod 44 is in three sections connected by two cross-heads 52 having bearing strips 55 and receiving a pin 60 passing through the toggle links 65. These pivot on a pin 71 passing through the links 72, 73, link 72 being mounted on a pivot 83 on a beam 84 supporting the blade 15. Pads 61 bear between the ends of pins 60, 71, 83 and the plates 3, 5, and lubrication passes from a reservoir in the beam 9 to the strips 55 passed ball or disc valves, Fig. 8 (not shown). One or more bearings (not shown) carried by the frame may support the rod 44 between the crossheads. Down strokes of the blade 15 are by the cylinder 46 or by this cylinder and cylinder 47, which also returns the blade, the piston-rods 44A, 44C, of cylinders 46, 47 being two of the sections of rod 44. Alternatively, a single double-acting, or two single-acting, cylinders may be used. A valve 106, Fig. 9, supplying the hold-down cylinders 94 and cylinders 46, 47 is controlled by two solenoids 107, 108, solenoid 107 setting the valve for supplying the cylinders 94 from a pump 104 upon operation of a switch 103 by the treadle 95. The rise in pressure operates a switch 111 that operates the solenoid 108, the combined effort of the solenoids effecting a further movement of the valve to supply the cylinders 46, 47 through pipe 112 or only cylinder 46 if valve 115 is closed. The escape of fluid from cylinder 47 is controlled by a valve 121. At the end of a stroke, an adjustable limit-switch 116 operated by a cross-head 52 or carrier 14 de-energizes solenoid 107, and solenoid 108 moves valve 106 into a position in which the pump supply is fed to pipe 117 for the return stroke. A relief valve 105 may also control the stroke-length. If valve 115 is closed, a valve 119 is opened at the same time to allow exhaust of the righthand side of cylinder 47. At the end of the return stroke, solenoid 108 is de-energized by a limit-switch 122 operated by the other crosshead 52 or the carrier 14. Specifications 922,934 and 896,761 are referred to. The fluid returning the blade may be at a lower pressure than that effecting shearing.