GB618546A - Improvements in or relating to fluid pressure operated engines, such as pneumatic picks or concrete breakers - Google Patents

Abstract

618,546. Percussive tools. TIERNEY, J. W., and HILLS, F. Oct. 4, 1946, Nos. 29612/46, 35295/46, and 6604/47. [Class 124] [Also in Group XXVI] In a pneumatic pick or concrete breaker, a resilient buffer is disposed between a slidably mounted cylinder head and a tool-chuck which is slidably mounted within an extension of the cylinder. In the form shown, an oil-proof rubber buffer 12 is disposed between a shoulder 11 formed by the front face of the larger-diameter portion 7a of a mushroomshaped sleeve 7 serving as the head of the cylinder 1 and the rear end of a sleeve member 9 forming a rearward extension of the chuck 6. The member 9 is surrounded by an outer stationary sleeve 13 and a second resilient buffer 17 may be arranged between an abutment 18 on the chuck 6 and a co-operating abutment on a retaining sleeve 14 rigidly secured to the sleeve 13. The piston 2 has a reduced-diameter plunger portion 3 and the annular chamber 1b so formed is supplied through a port 1a with compressed air which serves as a buffer for the piston and causes its return stroke. In a modification, the buffer 12 is replaced by one or a plurality of rings of sponge or cellular rubber, or of inflatable tubes, disposed between a pair of solid rings of rubber or like resilient material. In another modification, the plunger portion 3 is replaced by a separate anvil block.