Patent ID: 7572264

Claim:
A surgical instrument for driving a threaded member into a substrate, comprising: a drive shaft extending generally along a longitudinal axis and including a distal end portion releasably and rotationally engaged with the threaded member; a support member including a distal end positioned adjacent said distal end portion of said drive shaft, said drive shaft axially coupled with said support member to allow relative axial displacement therebetween, said drive shaft rotatably coupled with said support member by features that substantially prevent rotational displacement therebetween while allowing said relative axial displacement such that a rotational force applied to said support member is transmitted through said drive shaft to the threaded member, said features comprising a transverse projection positioned within an axially-extending groove, wherein said drive shaft includes an axially-extending shaft portion having a non-circular outer cross-section taken in a plane perpendicular to said longitudinal axis and positioned within an axially-extending passage portion defined by said support member; and a biasing member engaged with portions of said support member and said drive shaft to transmit an axial force from said support member to said drive shaft, said biasing member exerting an axial biasing force onto said drive shaft in a distal direction which is transmitted through said drive shaft to the threaded member as the threaded member is driven into the substrate, said axial force being limited as said distal end of said support member is engaged against a surface adjacent the substrate to correspondingly limit an axial force exerted onto the threaded member by said drive shaft to said axial biasing force to facilitate rotational disengagement of said distal end portion of said drive shaft from the threaded member.