GB191224090A - Improvements in Power Operated Portable Hammers for use with Percussive Tools for Rivetting, Caulking, Chipping and the like. - Google Patents

Abstract

24,090. Electric Hammers, Ltd., and Scott, J. Oct. 22. Percussive hand tools.-In a power-operated portable hammer having a hammer head reciprocated relatively to a tool held in the hammer casing, a piston block, reciprocated by a crank, is located in the hammer head and is elastically connected thereto by springs on opposite sides of the block. The handle a<2>, in two parts bolted together and secured to the hammer casing A by a nut a<3>, carries the driving-shaft D and crank-shaft C, which may be connected by a friction or other clutch E controlled by levers e<1>, e<5>; a spring e<2>, ball e<3>, and stud e<4> normally hold the clutch members apart. The crank c<2> engages the slotted head g<1> of a connecting-rod G secured to a piston block P arranged in the hammer head F; the slotted head g<1> engages guides H. Springs J, K, preferably under initial compression, transmit motion from the piston block P to the hammer head F, and spiral grooves f<1> in the latter prevent cushioning. One or more springs may be provided on each side of the piston block P and are arranged concentrically, adjacent springs being oppositely wound. Buffer springs may also be provided to act during only a part of the stroke. The driving-shaft D is driven by a flexible shaft and supported in a bearing d<1> which is threaded to receive the sheath of the flexible shaft. The piston block P may be connected to the crank in other ways, as by an oscillating connecting-rod, the piston block then having a trunk extension. Specification 9329/11 is referred to.