Sleeve-valve-controlled pneumatic in-hole impact drill - has sleeve valve tripped by movement of striking piston to allow complete filling of both working chambers with compressed air.

摘要

The stepped striking piston (1) slides backwards and forwards in a corresponding stepped bore of the impact drill body. In the starting position (fig 1) with the drill bit pressed against the work surface, compressed air passes along passages (3,4) and simultaneously fills chambers (6) behind and chambers (5) in front of the piston. The control sleeve (2) is constrained by the friction of self-adjusting ring seal (11) and remains where it is until, just before impact (fig 2), it is carried forward with the piston to close-off the air inlet to the rear chamber (6). With pressure now only in the front chamber (5) the piston returns and moves the control sleeve (2) back to its starting position, thus initiating another impact cycle. USE/ADVANTAGE - Impact drill with better utilisation of compressed air and improved performance within machine dimensional limits.