Fastener tools

A reaction transducer construction adapted to be mounted within a tool housing to provide a torque output signal from a power tool, comprising;

• a generally annular member having a stationary portion at one end adapted to be fixed to the housing, a reduced thin-walled central section adapted to extend within the housing and a section at the other end having torque responsive drive means formed thereon, and torsional strain responsive means carried by the central section and operable to provide a signal proportional to the strain in the central section.

A transducer construction for a power tool or the like having a motor, a torque output member, and drive means connecting said motor with said torque output member, said transducer construction comprising an annular member adapted to encircle at least a portion of said drive means and having one end thereof adapted to be fixed against rotation relative to said output member, an internal gear means at the other end thereof for so connecting said annular member to said drive means as to subject said annular member to at least a portion of the torque being transmitted by said drive means, and torsional strain responsive means carried by said annular member and operable to provide a signal proportional to the torsional strain in said annular member and consequently to the torque output at said torque output member.