GB1156824A - Vibratory Impact Tool. - Google Patents

Abstract

1,156,824. Percussive tools. GENERAL DYNAMICS CORP. 24 May, 1966 [24 May, 1965(2)], No. 22191/66. Heading B4C. [Also in Division E1] In an impact tool 50 a hammer 88 reciprocates in a bore connecting a plurality of cavities 74, 76, 78, 80, fluid being continuously supplied to one cavity 74 and the flow of fluid from this cavity to another cavity 76 being controlled by the movement of the hammer. The tool is slidably mounted on the tower of a mobile drill rig and is fed by a chain drive. The hammer 88 is floatingly supported in the equilibrium position (shown) by the pressure of fluid in a cavity 78, the pressure in the cavity being controlled by a pump 198 and a centering arrangement 90. Fluid from a large pressure chamber 66 (or an accumulator) is supplied to increase the pressure in a cavity 74 and causes the hammer 88 to commence oscillation, the fluid flowing past the top of the hammer through passages (not shown) into a cavity 76 (maintained at constant pressure by an accumulator, not shown) and back to the chamber through a pump 120. The pressure of the pump 198 may be adjusted to bias the hammer in one direction or the other. As the pressure in the cavity 76 increases the hammer strikes the anvil which comprises a titanium rod 224 attached to a drill steel 214 carrying the drill 228. The anvil and steel are rotated by mechanism in a cavity 82, and a hose may be attached to a casing part 284 to supply flushing fluid to the bit. In a modification (Fig. 11, not shown) the apparatus is inverted and adapted to be mounted on a lift for overhead drilling. In the modifications described below the steel and anvil are not rotated. Modifications include a restriction in the connection between the centering arrangement and the cavity (78) (Figs. 17, 18, not shown), the cavities (74), (76) and (78) and the centering arrangement connected to a single pump (Figs. 18, 19, not shown), and an anvil supported in a housing below the cavity (78), (Fig. 19, 20, not shown), the hammer and anvil connected by a lost motion connection (Fig. 20, not shown), the anvil dispensed with and the tool given an aperture for a pile (Fig. 2, not shown), the anvil including a cushion of oil (Fig. 23, not shown), the centering arrangement dispensed with and the pressure of fluid supplied to the cavity 78 controlled by a valve (Fig. 15, not shown), and the hammer housing, a rodlike extension which strikes the anvil (Fig. 12, not shown). Fig. 13, shows a construction in which the hammer 400 acts as a valve at each end, fluid being supplied to cavities 404, 408 and discharging from cavity 406. In a modified construction (Fig. 16, not shown) the tool is connected to a pump (508) and the hammer (470) is shaped to alternately supply fluid to and discharge fluid from cavities (488), (490).