US Patent 7197964 Wrench

A wrench (1) is disclosed having a handle (3) mounted pivotally with a head portion (2) for engaging a drive socket to tighten or slacken a fastener such as a nut, bolt or screw, and a resilient split ring (5) as operative portion intermediate the handle (3) and head portion (2). The head portion (2) has an aperture into which the split ring (5) is sprung to define a radial gap in the split ring (5) and a camming arm (33, 34) extending radially outwardly from each end of the split ring (5) respectively. The split ring (5) also has stops (37, 38) engaging the head portion under the natural resilience in the split ring (5) to prevent undue rotation of the ring in the head portion.