GB905115A - Improvements relating to hydraulically operable tools - Google Patents

Abstract

905,115. Shearing; bending. McNAIR, D. G. March 6, 1961 [Dec. 4, 1959], No. 41203/59. Class 83 (4). An hydraulically-operable reciprocating tool is controlled by valve means comprising a reciprocable piston, a spring urging the piston to an exhaust position and a lever actuable to move the piston to an inlet position against the spring action. The device comprises a tool head 1 carrying a tool 39 and mounted on a ram 2 which slides in cylinder 4 and is biased to the inward position by a spring 22. One end of the cylinder is closed by a head 5 having a bore 6 in which slides a waisted piston 7. Hydraulic fluid reaches the cylinder through a radial inlet port 8 and a passage 4 and is exhausted through an outlet 9. The piston has an extension 11 which is acted on by an arm 18 which is part of a lever 16 pivoted to the head 5 and which also has a part 19 to form a hand-operated trigger. The piston is urged upward to a position in which the inlet 8 is connected to the outlet 9 by a spring 13 which surrounds a stem 12 projecting downwardly from the head. Clamped between the end face of the ram and the tool head 1 is a radial arm 25 which has a rearwardly-directed bifurcated part 28 carrying a cross-pin 29. The cross-pin engages a lost-motion slot in one end of a rod 30 which is pivoted at its other end to one arm of a bell-crank mounted on a pivot 34. The other arm 35 of the crank engages the stem 12 when the ram moves the rod 30 and raises the piston 7 to the position in which the exhaust port 9 is opened. The rod 30 is biased to a position in which the part 35 is clear of the stem 12 by a spring 36. When used as a barstraightener the device also comprises a pair of spaced-apart transversely grooved work supports (only one shown) 41, supported by arms 43 and 44. The tool is applied to the work by a handle 15, the trigger 19 is operated to depress the piston 7 and the return movement is initiated automatically when the ram reaches the end of its travel and operates the bellcrank arm 35. In a modification (Fig. 5), a shear blade 46 which has a cutting edge 46A is detachably secured to the spigot 23 of the ram 2 by a cross-pin 48. The co-operating work support (not shown) comprises a transversely grooved block secured to the cylinder.