Transducer for indicating torque

Claim 2

A transducer construction adapted for use with a power tool or the like having a motor, a torque output member, 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 and be connected to said drive means so as to be subjected to at least a portion of the torque being transmitted thereby, 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, said annular member including a torsionally resilient portion, said torsionally resilient portion including at least one thin-walled section of said annular member, the radially inner periphery of said thin-walled section being cylindrical, including eight symmetrically arranged flat surface portions on the outer periphery of said torsionally resilient portion providing a plurality of said thin-walled sections, and said torsional strain responsive means including a plurality of strain responsive elements mounted on said flat surface portions.

Claim 3

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.

Claim 4

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.

Claim 5

A reaction transducer adapted to be mounted within a tool housing to provide an output signal representing torque delivered by the tool, as defined in claim 2, wherein the strain responsive means includes a plurality of strain gauges mounted on the outer surface of the central section.

Claim 6

A reaction transducer adapted to be mounted within a tool housing to provide an output signal representing torque delivered by the tool, as defined in claim 3, in which the central section has a plurality of flat surfaces on the outer periphery thereof extending in chordal directions, and each of said strain gauges being mounted on one of the central section chordal surfaces.

Claim 7

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.

Claim 8

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.

Claim 9

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, as defined in claim 5, wherein only the second gear set engages and reacts against the enlarged section ring gear.

Claim 10

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, as defined in claim 5, wherein the wall thickness of the central section is substantially less than the stationary portion and the enlarged section.

Claim 11

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, as defined in claim 7, wherein the radially outer periphery of said thin-walled central section has at least one flat surface portion, and said torsional strain responsive means being mounted on said flat surface portion.

Claim 12

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, as defined in claim 8, including a plurality of said flat surface portions on the outer periphery of said central section, and said torsional strain responsive means including a plurality of strain responsive elements each mounted on one of said flat surface portions.

Claim 13

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, as defined in claim 9, wherein each of said torsional strain responsive elements includes a strain gauge mounted on one of said flat surface portions.

Claim 14

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, as defined in claim 10, wherein the axes of the strain responsive elements of said strain gauges are substantially parallel to the lines of maximum strain in said central section when said annular means is subjected to a torsional force.

Claim 15

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, as defined in claim 11, wherein the axes of the strain responsive elements of said strain gauges are disposed at an angle of substantially 45 degrees with respect to the axis of said annular means.

Claim 16

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, as defined in claim 12, wherein the axes of said strain gauges are disposed at alternate angles of substantially 45 degrees with respect to the axis of said annular means.

Claim 17

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, and planetary gearing driven by the motor drivingly connected to the torque output member, said planetary gearing engaging and reacting against the enlarged section ring gear to transmit torque to the central section, said planetary gearing including a first stage planetary gear set and a second stage planetary gear set and with only said second stage planetary gear set engaging and reacting against the enlarged section ring gear, said annular central section having an outer diameter and thickness selected for a given sensitivity to reduce the radial distortion produced by the second stage planetary gear set acting against the enlarged section ring gear.

Claim 18

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, and planetary gearing driven by the motor drivingly connected to the torque output member, said planetary gearing engaging and reacting against the enlarged section ring gear to transmit torque to the central section, said planetary gearing including a first stage planetary gear set and a second stage planetary gear set and with only said second stage planetary gear set engaging and reacting against the enlarged section ring gear, said annular central section having an outer diameter and thickness selected for a given sensitivity to reduce the radial distortion produced by the second stage planetary gear set acting against the enlarged section ring gear.

Claim 19

A transducer assembly adapted for use in the housing of a power tool having a motor and a torque output member, as defined in claim 14, wherein said first and second planetary gear sets are unsupported in the annular means to increase the accuracy of the transducer.

Claim 20

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.

Claim 21

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.

Claim 22

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.

Claim 23

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.