| 摘要 |
A hole opener (10) having a tubular body (11) with threaded ends (12, 14) for connection in a drill string. The hole opener provides slots or grooves (21, 21') along its longitudinal axis (16) into which are inserted cutter arm support members (30, 30', 60, 60') which may be screwed, (43) pinned (68) or bolted (168) to the body (11) to permit easy replacement of the support arms (30). The grooves (21, 21') in the body (11) of the hole opener (10) also provide a spindle (20) spatially aligned with the groove (21, 21') to support the proximal end of a rotatable journal body (28) supporting the cutter body (25) providing hard facing for grinding of the bore hole to be enlarged. The support arms (30) at their distal end provide further support for the cutter journals (70). The hole opener (10) also may provide pressure compensated lubrication mechanism (71) to provide grease to the bearing surfaces to increase their service life and thereby extend the useful life of the tool. |
