Reciprocating drive apparatus

Abstract

A reciprocating drive apparatus (10) comprises a housing (12) and a mandrel (14), wherein the mandrel (14) and the housing (12) are configurable to be rotated relative to each other. The apparatus (10) further comprises a reciprocating piston (16) mounted within a piston housing (18) to define a piston chamber (20a), wherein the piston (16) is moveable in reverse first and second axial directions (A,B), and a rotary valve assembly (24) comprising a valve inlet (28) for communicating with a pressure region (P) and a valve exhaust (30) for communicating with an exhaust region (E). The rotary valve assembly (24) is operated by relative rotation between the mandrel (14) and the housing (12) to be cyclically reconfigured between a pressure configuration and an exhaust configuration. When in the pressure configuration the piston chamber (20a) is in pressure communication with the valve inlet (28) and isolated from the valve exhaust (30) to permit the piston to move in the first axial direction (A) in accordance with the piston chamber being pressurised via the valve inlet (28). When in the exhaust configuration the piston chamber (20a) is isolated from the valve inlet (28) and in pressure communication with the valve exhaust (30) to permit the piston chamber to be depressurised and the piston (16) to move in the second axial direction (B). Movement of the piston (16) in at least one of the first and second axial directions (A,B) generates an applied force within the apparatus (10) and/or an applied force output from the apparatus (10).

Dependencies are inferred from the claim text.