GB622709A - Improvements in or relating to percussive tools - Google Patents

Abstract

622,709. Percussive drills. CHICAGO PNEUMATIC TOOL CO. March 3, 1947, No. 5983. Convention date, Aug. 15, 1946. [Class 124] [Also in Groups XXIV and XXVII] In a percussive tool driven by an internal combustion engine, having a first crankshaft driving a second crankshaft, a hammer assembly, including a hammer piston reciprocating within a sliding member, reciprocates in a barrel member mounted on the tool housing, connecting means from the second crankshaft transmitting reciprocating motion to the hammer assembly, and a collared working implement, receiving intermittent blows from the hammer piston, arranged within the barrel. As shown a hammer piston 19, slidingly arranged within a cage 20 which is reciprocated by a connecting rod 24 driven by a crankshaft, delivers blows on a steel 18 having a collar 42 mounted in the space between two snubber rings 32 and 35 separated by a flange 33. The snubber rings are maintained in contact with the flange 33 by springs 31 and 36 which also cushion any excess movement of the steel. A chamber 52 above and a chamber 53 below the cage 20 are connected by passages and ports and may have ports to the atmosphere. The piston 19 has a cupshaped recess 59 which loosely receives a depending portion 56 of the cage head. The upward movement of the cage causes a vacuum in a space 57 and results in the upward movement of the piston, the downward movement of the cage compressing the air in the space 57 and causing the piston to deliver a blow on the steel. One of the handles of the tool may operate a starter for the internal combustion engine and may be locked in a position against the body of the tool Fig. 1 (not shown).