A power tool includes a housing, a drive mechanism supported within the housing, a spindle operatively coupled to an output of the drive mechanism such that torque from the drive mechanism rotates the spindle about an axis, and a clutch assembly configured to selectively limit torque transfer from the drive mechanism to the spindle. The clutch assembly includes a plurality of rolling elements, a biasing member configured to bias the plurality of rolling elements into engagement with the output of the drive mechanism, and a sleeve movable along the axis to adjust a torque limit of the clutch assembly by varying a preload of the biasing member. The sleeve is made of a high-temperature, engineering thermoplastic.

A power tool includes a housing, a drive mechanism supported within the housing, a spindle operatively coupled to an output of the drive mechanism such that torque from the drive mechanism rotates the spindle about an axis, and a clutch assembly configured to selectively limit torque transfer from the drive mechanism to the spindle. The clutch assembly includes a plurality of rolling elements, a biasing member configured to bias the plurality of rolling elements into engagement with the output of the drive mechanism, and a sleeve movable along the axis to adjust a torque limit of the clutch assembly by varying a preload of the biasing member. The sleeve is made of a high-temperature, engineering thermoplastic.

A rotary power tool includes a housing and a drive mechanism disposed within the housing. The drive mechanism includes an electric motor, a transmission operably coupled to the electric motor, a spindle operably coupled to an output of the transmission, the spindle configured to transmit torque generated by the electric motor to a working tool bit, and a clutch disposed between the output of the transmission and the spindle. The clutch includes a plurality of spherical rolling elements configured to engage the output of the transmission, a plurality of cylindrical clutch elements, and at least one biasing member configured to bias the cylindrical clutch elements towards the spherical rolling elements. Each of the cylindrical clutch elements includes a length measured parallel to a rotational axis of the spindle and a diameter, and the diameter is greater than the length.

A rotary power tool includes a housing and a drive mechanism disposed within the housing. The drive mechanism includes an electric motor, a transmission operably coupled to the electric motor, a spindle operably coupled to an output of the transmission, the spindle configured to transmit torque generated by the electric motor to a working tool bit, and a clutch disposed between the output of the transmission and the spindle. The clutch includes a plurality of spherical rolling elements configured to engage the output of the transmission, a plurality of cylindrical clutch elements, and at least one biasing member configured to bias the cylindrical clutch elements towards the spherical rolling elements. Each of the cylindrical clutch elements includes a length measured parallel to a rotational axis of the spindle and a diameter, and the diameter is greater than the length.

A power transmission device has a first clutch member 4a coupled to an output member 3. A second clutch member 4b has a plurality of driven-side clutch plates 7. A back-torque transmitting cam presses the drive-side clutch plates 6 and the driven-side clutch plates 7 against each other by moving the second clutch member 4b when a rotational force is input to the first clutch member 4a. A cushioning member 12 is interposed between the first clutch member 4a and the second clutch member 4b. The cushioning member 12, by being compressed, applies an urging force while allowing movements of an interlocking member 9 and a pressure member 5 in a process where the interlocking member 9 moves and the pressure member 5 moves from the inactive position toward the active position.

A power transmission device has a first clutch member 4a coupled to an output member 3. A second clutch member 4b has a plurality of driven-side clutch plates 7. A back-torque transmitting cam presses the drive-side clutch plates 6 and the driven-side clutch plates 7 against each other by moving the second clutch member 4b when a rotational force is input to the first clutch member 4a. A cushioning member 12 is interposed between the first clutch member 4a and the second clutch member 4b. The cushioning member 12, by being compressed, applies an urging force while allowing movements of an interlocking member 9 and a pressure member 5 in a process where the interlocking member 9 moves and the pressure member 5 moves from the inactive position toward the active position.

A power transmission device has a first pressure member (5a), a second pressure member (5b) and a back-torque transmitting cam. The first pressure member (5a) presses the drive-side clutch plates (6) and the driven-side clutch plates (7) against each other. The second pressure member (5b) releases a press-contact force between the drive-side clutch plates (6) and the driven-side clutch plates (7). The back-torque transmitting cam moves the second pressure member (5b) relative to the first pressure member (5a) to keep pressing the drive-side clutch plates (6) and the driven-side clutch plates (7) against each other when a rotational force is input to the clutch member (4), via the output shaft (3), in a process where the weight member (8) moves from the radially-outer position to the radially-inner position and the first pressure member (5a) moves to follow the interlocking member (9).

A power transmission device has a first pressure member (5a), a second pressure member (5b) and a back-torque transmitting cam. The first pressure member (5a) presses the drive-side clutch plates (6) and the driven-side clutch plates (7) against each other. The second pressure member (5b) releases a press-contact force between the drive-side clutch plates (6) and the driven-side clutch plates (7). The back-torque transmitting cam moves the second pressure member (5b) relative to the first pressure member (5a) to keep pressing the drive-side clutch plates (6) and the driven-side clutch plates (7) against each other when a rotational force is input to the clutch member (4), via the output shaft (3), in a process where the weight member (8) moves from the radially-outer position to the radially-inner position and the first pressure member (5a) moves to follow the interlocking member (9).

In response to a torque that is applied to a clutch module not exceeding a torque threshold, the clutch module is locked where a blade is configured to be at a first pitch angle in response to the clutch module being locked. In response to the torque that is applied to the clutch module exceeding the torque threshold, the clutch module is released where the blade has a range of motion which extends from the first pitch angle to a second pitch angle in response to the clutch module being released.

An overload limiting device includes: a rolling element; a rotatable first rotation member having a housing portion that houses the rolling element; a rotatable second rotation member having an engagement recess portion that engages detachably with the rolling element housed in the housing portion, the second rotation member being arranged opposing the first rotation member; a biasing member that biases the rolling element toward the engagement recess portion; and an adjustment nut that adjusts a biasing force of the biasing member by moving in a rotation axis direction of the first rotation member, the adjustment nut being provided to the first rotation member, the first rotation member including a scale showing a position of the adjustment nut in the rotation axis direction.