GB1286518A - Fluid operated hammers - Google Patents

Abstract

1286518 Hammers SPETSIALNOE KONSTRUKTORSKOE BJURO GIDROIMPULSNOI TEKHNIKI SIBIRSKOGO OTDELENIA AKADEMII NAUR USSR and INSTITUT GIDRODINAMIKI SIBIRSKOGO OTDELENIA AKADEMII NAUK USSR 21 Nov 1969 57051/69 Heading B4C A percussive hammer comprises a working element 14 connected by a resilient coupling to a rod 12 rigid with a piston 2 which is such as to permit angular deflection of the piston and rod relative to the axis of cylinder 1. Lateral deflections of the working member are cushioned by pistons 26 movable in cylinders against gas therein. The resilient coupling comprises resilient members 25 on either side of a member 22 rigidly connected with the rod. An annular member 20 carrying a sealing ring 21 is movable normal to the cylinder axis in a groove 19 to accommodate angular deflection of the rod. Compressed gas is contained in a plurality of cylinders 7 which via passages 5 are in constant communication with chamber 3 and with a cylinder 53. A fluid pressure pump 9 supplies fluid so that when a valve sleeve 11 is in the position illustrated, fluid in chamber 4 acts on piston 2 to force the piston on a return stroke. Engagement of the piston with projection 51 of a movable member 50 will cause via linkage 49, 58 and 59 movement of the valve sleeve 11 so as to open chamber 4 to exhaust. Thus pressure of fluid within that chamber drops and the piston is driven on its working stroke by gas pressure in the cylinders 7. Outflow of fluid from the chamber 4 during the working stroke forces the valve sleeve 11 to a position in which the ports 10 are fully open to exhaust. When the implement 14 impacts a workpiece, the valve 11 will be returned to the illustrated condition by gas acting on piston 52, and the piston 2 may be cushioned if its working stroke exceeds a predetermined length by part 35 entering space 34. In an alternative embodiment (Fig. 2, not shown) the piston (2) is slidable within a sleeve (36) closed at one end, the sleeve wall at the open end of the sleeve being tapered and provided with notches (33). The sleeve is slidable relative to and within the cylinder so that when the piston overtravels the ports 10 are initially closed by the sleeve which then reverses its movement to open the ports 10.