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A percussive drill has a bit holder, a percussive drive including a ram slidably mounted in a hollow piston, and a drive transmission for reciprocating the ram in the piston via an air cushion. The forward travel of the ram during percussive action of the drill is limited by a drill bit or an interm

A percussive drill has a bit holder, a percussive drive including a ram slidably mounted in a hollow piston, and a drive transmission for reciprocating the ram in the piston via an air cushion. The forward travel of the ram during percussive action of the drill is limited by a drill bit or an intermediate member interposed between the drill bit and the ram. A member holds the ram in a position further forward, than that attained during the above limited travel allowed the ram, when percussive action is not desired. The holding member is resilient, has a U shaped cross-section, and is entered by the ram as it moves to the further forward position, the ram then forming a seal therewith, and the member also functioning to absorb the energy of an impact by the ram.

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A percussive drill, comprising: a bit holder; a percussive drive including a ram slidably mounted in a hollow piston; drive means for reciprocating the ram in the piston via an air cushion formed between said piston and said ram, the forward travel of the ram during percussive action of the drill be

A percussive drill, comprising: a bit holder; a percussive drive including a ram slidably mounted in a hollow piston; drive means for reciprocating the ram in the piston via an air cushion formed between said piston and said ram, the forward travel of the ram during percussive action of the drill being limited by a drill bit or an intermediate member interposed between the drill bit and the ram; a resilient annular hollow-section member for holding the ram, when percussive action is not desired, in a position further forward than the forward travel to which the ram is limited during percussive action; said resilient annular hollow-section member being entered by the ram as the latter moves to said position further forward and the ram forming a seal with said hollow-section member, the latter also absorbing the energy of an impact by the ram thereagainst; and said piston having a forward portion of wider internal cross-section than a rear portion of said piston and in which rear portion said ram reciprocates during percussive action of the drill, and said ram being located fully in said forward portion in said position further forward whereby the air cushion between the piston and the ram is vented.