Abstract: A torque wrench comprises a body member containing a piston-cylinder assembly to the piston of which is secured a shuttle member reciprocable with the piston within the body member, and a housing mounted on the body member and including a drive member pivotal about an axis and having a neck portion radially remote from the pivot axis. The shuttle member has a cylindrical bore therein the central longitudinal axis of which extends parallel with the pivot axis of the drive member, said bore housing a cylindrical drive pin in which is formed a transverse bore, the neck portion of the drive member being received within said bore whereby, on linear movement of the piston, the drive member is pivoted about the pivot axis with the neck portion of the drive member undergoing guided sliding movement in the bore of the drive pin, and the drive pin pivoting about the central longitudinal axis of the bore in the shuttle member.

Abstract: A hydraulic torque wrench comprises a body member housing a piston-cylinder assembly and a drive member pivotal by the piston of the assembly about an axis radially spaced from the line of action of the piston, the drive member carrying a shaft or socket connected to the drive member by a ratchet connection. A spherical bearing member is mounted to the end of the piston for guided linear reciprocal movement therewith, a neck portion of the drive member being slidably received in a bore in the bearing member whereby, as the drive member is pivoted by movement of the piston, the neck portion of the drive member undergoes guided sliding movement in the bore of the bearing member, the bearing member rotating relative to the piston such that the perpendicular distance between the line of action of the piston and the pivot axis remains constant.