Reversible pneumatic impacting arrangement for driving holes in the ground

摘要

PCT No. PCT/SU84/00076 Sec. 371 Date Oct. 24, 1985 Sec. 102(e) Date Oct. 24, 1985 PCT Filed Dec. 28, 1984 PCT Pub. No. WO85/03963 PCT Pub. Date Sep. 12, 1985.A reversible air-operated percussive action machine for driving holes in the ground has a housing accommodating a hammer 2 capable of reciprocating therein. An air distributor 3 is arranged in the hammer 2 in the form of a fixed tube 12 and a valving member 13 movable relative to the tube. Defined between the tube 12 and valviong member 13 is an accumulating chamber 18 which communicates with an air feeding line 4. An air restrictor is further provided for discharging air from the accumulating chamber 18 when the supply of compressed air to the air feeding line is terminated. The valving member 13 spring-loaded relative to the tube 12 by a spring arranged so that during feeding compressed air to the accumulating chamber 18 the valving member 13 is acted upon by a pressure force directed counter to the action of the spring.