PNEUMATIC REVERSIBLE PERCUSSIVE DEVICE FOR DRIVING HOLES IN EARTH

摘要

PCT No. PCT/SU85/00049 Sec. 371 Date Feb. 10, 1986 Sec. 102(e) Date Feb. 10, 1986 PCT Filed Jun. 20, 1985 PCT Pub. No. WO86/00357 PCT Pub. Date Jan. 16, 1986.An air-operated reversible percussive action machine comprises a housing (1) accommodating a reciprocating hammer (2). Secured inside the housing (1) is a stepped tube (5). The step of larger diameter of the tube (5) is received by a cavity (4) of the hammer (2) and has a port (12) for distributing air flow and feeding it to the interior of the housing (1). The tube (5) receives a sleeve (14) having a port (15) alternately communicable with the port (12) of the tube (5) in one of its two positions. One end face of the tube (5) has a projection (13) in the form of a sector of a circle, whereas the sleeve (14) is provided with a radial projection (16) so that in turning the sleeve (14) its projection (16) bears on one of the side walls of the projection (13) of the sleeve (5) thus assuming one of the two positions.