Transducer for indicating torque

A reaction transducer adapted to be mounted within a tool housing having a drive train therein to provide an output signal representing torque delivered by the tool, comprising;

• generally annular means having a stationary portion at one end adapted to be non-rotatably fixed to the tool housing, said annular means having an annular central section adapted to extend within the housing, said annular means having an enlarged section adjacent the central section opposite the stationary portion having gear means to engage and react against the drive train, and torsional strain response means carried by the central section and operable to provide a signal proportional to the strain in the central section, said central section having an outer diameter less than the outer diameter of the enlarged section, said central section having an outer diameter and thickness selected for a given sensitivity to reduce the radial distortion produced by the drive train acting against the gear means.

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, comprising;

• a generally annular means having a stationary portion at one end adapted to be non-rotatably fixed to the tool housing, said annular means having an annular central section adapted to extend within the housing, said annular means having an enlarged section adjacent the central section opposite the stationary portion with an internal ring gear, torsional strain responsive means carried by the central section and operable to provide a signal proportional to the strain in the central section and the torque delivered by the tool, said central section having an outer diameter less than the outer diameter of the enlarged section, planetary gearing driven by the motor and drivingly connected to the torque output member, including a first planetary gear set and a second planetary gear set, said second planetary gear set engaging and reacting against the enlarged section ring gear to transmit torque to the central section, bearing means fixed with respect to the housing supporting the first planetary gear set, and bearing means fixed with respect to the housing supporting the second planetary gear set, said first and second planetary gear sets being unsupported in the teeth of the internal ring gear.

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, comprising;

• a generally annular transducer means having a stationary portion at one end adapted to be non-rotatably fixed to the tool housing, said annular means having an annular central section adapted to extend within the housing, said annular means having an enlarged section adjacent the central section opposite the stationary portion with an internal ring gear, torsional strain responsive means carried by the central section and operable to provide a signal proportional to the strain in the central section and the torque delivered by the tool, and planetary gearing driven by the motor and drivingly connected to the torque output member, said planetary gearing including a planet carrier having a plurality of planet gears engaging and reacting against the ring gear of the annular transducer means, said central section having an outer diameter less than the outer diameter of the enlarged section to permit an increase in the thickness of the central section, said central section having an outer diameter and thickness selected for a given sensitivity to reduce the radial distortion produced by the planet gears acting against the transducer ring gear.

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, comprising;

• a generally annular transducer means having a stationary portion at one end adapted to be non-rotatably fixed to the tool housing, said annular means having an annular central section adapted to extend within the housing, said annular means having an enlarged section adjacent the central section opposite the stationary portion with an internal ring gear, torsional strain responsive means carried by the central section and operable to provide a signal proportional to the strain in the central section and the torque delivered by the tool, and planetary gearing driven by the motor and drivingly connected to the torque output member, said planetary gearing including a planet carrier having a plurality of planet gears engaging and reacting against the ring gear of the annular transducer means, said central section having an outer diameter less than the outer diameter of the enlarged section, said central section having an outer diameter and thickness selected for a given sensitivity to reduce the radial distortion produced by the planet gears acting against the transducer ring gear.