GB312525A - Improvements in metal cutting shears - Google Patents

Abstract

312,525. Hancock, L. J. July 3, 1928. Shearing. - A portable metalshearing machine having a movable blade operated by fluid pressure comprises a U-shaped frame 1 of H-section carrying a fixed blade 9 and a movable blade 10. The latter is attached to a fluid-pressure cylinder 2 whose piston-rod 3 is shouldered and secured to the frame. Two side strips 6 on the cylinder slide in guides 7 on arms 8 of the frame and a rubber buffer 27 cushions the return stroke. Fluid is admitted to opposite sides of the piston 4 by two passages in the piston-rod connected to a valve box 11 whose valve stems 18 are arranged in two pairs, each operated by a pivoted plate 19. Two spring triggers 14 are provided, the action being such that on depressing one trigger a plate 19 is raised to admit fluid in part of the piston and connect the space behind the piston to exhaust, while on depressing the other trigger the supply and exhaust are reversed. When the cylinder reaches the forward limit of its cutting stroke the lower part thereof engages two stops 20, whereof one draws forwards a spring-controlled rod 15 and causes a ramp 22 to raise one of the plates 19 through a rod 23 and admit fluid to the rear end of the cylinder, while the other acts through a second rod on a lever 24 to which withdraws a sleeve 25 from under the other plate 19 and allows it to fall, even though the operator continues to depress the corresponding trigger 14, and thus cuts off the supply of fluid to the front of the cylinder. This stop motion prevents the cylinder from jarring against the opposite limb of the frame when the cut has been completed. A handle 28 is provided on the frame.