Patent attributes
A tool assembly (10), for example a hydraulic or pneumatic hammer assembly, includes a housing (11) defining a chamber (16), a removable reciprocating work tool (20) arranged in the chamber, and a tool retention member (80) having an aperture through which the work tool extends. The housing (11) includes an engaging structure (50) which permits the engagement of the tool retention member (80) with the housing by relative rotation of the tool retention member and housing. The work tool (20) is provided with retention structure (44) such as a retaining flange which prevents the removal of the work tool from the housing when the tool retention member is engaged with the housing. At least some of the disclosed embodiments may eliminate the need for a retainer pin, thereby allowing the work tool to rotate, possibly avoiding wear, increasing tool life and simplifying tool replacement.