An electric power tool in one aspect of the present disclosure includes a motor, an output shaft, a torque detector, a correction circuit, and an output circuit. The correction circuit corrects a drive command value based on load torque detected by the torque detector. The drive command value indicates a magnitude of electric power to be supplied to the motor. The output circuit outputs a drive signal indicating the drive command value. The drive circuit (i) receives the drive signal from the output circuit and (ii) supplies electric power in accordance with the drive signal to the motor to drive the motor.

An electric power tool in one aspect of the present disclosure includes a motor, first and second paths respectively and electrically connect the motor to a DC power supply, a first switch on the first path, a second switch on a the second path, a first drive circuit, and first and second holding circuits. The first drive circuit (i) switches the first switch to the ON-state and (ii) outputs a first drive signal to the second switch. The first holding circuit holds the second switch in the ON-state while the first drive circuit is activated. The second holding circuit holds the first switch in the OFF-state based on the second switch being held in the ON-state.

An electric power tool in one aspect of the present disclosure includes a motor, first and second paths respectively and electrically connect the motor to a DC power supply, a first switch on the first path, a second switch on a the second path, a first drive circuit, and first and second holding circuits. The first drive circuit (i) switches the first switch to the ON-state and (ii) outputs a first drive signal to the second switch. The first holding circuit holds the second switch in the ON-state while the first drive circuit is activated. The second holding circuit holds the first switch in the OFF-state based on the second switch being held in the ON-state.

A power tool and a safety control circuit module and a safety control method thereof are provided. The power tool includes a power supply device, a control processing device, a safety control circuit module, and a power output device. The control processing device is electrically connected with the power supply device. The safety control circuit module includes a first switch control circuit, a second switch control circuit, a third switch control circuit, a first resistor, and a first diode. The power output device includes a first power connection terminal and a second power connection terminal. Before switch units of the control circuits are controlled, the control processing device detects whether the switch unit has failed, so as to increase safety.

A power tool and a safety control circuit module and a safety control method thereof are provided. The power tool includes a power supply device, a control processing device, a safety control circuit module, and a power output device. The control processing device is electrically connected with the power supply device. The safety control circuit module includes a first switch control circuit, a second switch control circuit, a third switch control circuit, a first resistor, and a first diode. The power output device includes a first power connection terminal and a second power connection terminal. Before switch units of the control circuits are controlled, the control processing device detects whether the switch unit has failed, so as to increase safety.

A portable torque power tool is disclosed herein and includes: a motor to generate a turning force; a drive to transfer the turning force; a turning force multiplication mechanism assembly to multiply the turning force; a shifter assembly to shift the tool between a lower speed/higher torque (LSHT) mode and a higher speed/lower torque (HSLT) mode; a torque transducer to measure torque output; wherein torque output is controlled by the torque transducer in LSHT mode; and wherein torque output is controlled by motor current in HSLT mode. In one embodiment of the present application, the torque transducer is a wireless torque transducer assembly formed at or near an output of a housing of the turning force multiplication assembly to improve measurement accuracy of torque output. Advantageously, simplified tool and system design and operation; reduced tool and system size; expanded functionality, greater durability and intuitive usability; and increased tool and system portability, efficiency, reliability and repeatability, all at low cost, are achieved. Further disclosed herein is an operation parameter regulation unit for use with a bolting system having a plurality of networked electrically powered torque tools and/or drive portions of torque tools described above for simultaneous tightening of industrial threaded fasteners. The operation parameter regulation unit includes: a processing unit; an output unit connected and/or integrated with the processing unit; an input unit connected and/or integrated with the processing unit; an activation unit connected and/or integrated with the processing unit for activating operation units of the plurality of networked electrically powered torque tools and/or drive portions of torque tools; and a control unit for controlling operation parameters of each of the plurality of networked electrically powered torque tools and/or drive portions of torque tools to maintain a difference between the operation parameters within a predetermined value. Advantageously, innovations disclosed in this application include operation parameter regulation units for bolting systems having a plurality of networked electrically powered torque tools and/or drive portions of torque tools for simultaneous tightening of industrial threaded fasteners. Indeed SIMULTORC® is achievable with a plurality of networked electrically powered torque tools and/or drive portions of torque tools, particularly those of the handheld and/or mobile variety.

A portable torque power tool is disclosed herein and includes: a motor to generate a turning force; a drive to transfer the turning force; a turning force multiplication mechanism assembly to multiply the turning force; a shifter assembly to shift the tool between a lower speed/higher torque (LSHT) mode and a higher speed/lower torque (HSLT) mode; a torque transducer to measure torque output; wherein torque output is controlled by the torque transducer in LSHT mode; and wherein torque output is controlled by motor current in HSLT mode. In one embodiment of the present application, the torque transducer is a wireless torque transducer assembly formed at or near an output of a housing of the turning force multiplication assembly to improve measurement accuracy of torque output. Advantageously, simplified tool and system design and operation; reduced tool and system size; expanded functionality, greater durability and intuitive usability; and increased tool and system portability, efficiency, reliability and repeatability, all at low cost, are achieved. Further disclosed herein is an operation parameter regulation unit for use with a bolting system having a plurality of networked electrically powered torque tools and/or drive portions of torque tools described above for simultaneous tightening of industrial threaded fasteners. The operation parameter regulation unit includes: a processing unit; an output unit connected and/or integrated with the processing unit; an input unit connected and/or integrated with the processing unit; an activation unit connected and/or integrated with the processing unit for activating operation units of the plurality of networked electrically powered torque tools and/or drive portions of torque tools; and a control unit for controlling operation parameters of each of the plurality of networked electrically powered torque tools and/or drive portions of torque tools to maintain a difference between the operation parameters within a predetermined value. Advantageously, innovations disclosed in this application include operation parameter regulation units for bolting systems having a plurality of networked electrically powered torque tools and/or drive portions of torque tools for simultaneous tightening of industrial threaded fasteners. Indeed SIMULTORC® is achievable with a plurality of networked electrically powered torque tools and/or drive portions of torque tools, particularly those of the handheld and/or mobile variety.

A power-driven tool may include a clutch mechanism selectively provides for engagement between and transmission mechanism and an output mechanism of the tool. The clutch mechanism may include a variable rate, or a dual rate biasing mechanism. mechanism that transmits power from a motor to an output device. A speed selection mechanism may be coupled to the transmission mechanism, to control a speed reduction through the transmission mechanism, and an output speed of the tool. The transmission mechanism may employ a compound, stepped, planetary gear assembly, to provide for an axially compact arrangement of transmission mechanism components, to reduce an axial length of the tool. The speed selection mechanism may employ a multi-staged grounding device, corresponding to the reduced axial length of the transmission mechanism.

A power-driven tool may include a clutch mechanism selectively provides for engagement between and transmission mechanism and an output mechanism of the tool. The clutch mechanism may include a variable rate, or a dual rate biasing mechanism. mechanism that transmits power from a motor to an output device. A speed selection mechanism may be coupled to the transmission mechanism, to control a speed reduction through the transmission mechanism, and an output speed of the tool. The transmission mechanism may employ a compound, stepped, planetary gear assembly, to provide for an axially compact arrangement of transmission mechanism components, to reduce an axial length of the tool. The speed selection mechanism may employ a multi-staged grounding device, corresponding to the reduced axial length of the transmission mechanism.

The electric work machine in one aspect of the present disclosure includes an output shaft, a motor, a current measuring circuit, and a controller. The current measuring circuit measures a current value, the current value corresponding to a magnitude of a drive current flowing through the motor. The controller sets a maximum value and a threshold. The controller calculates the correction value less than or equal to the maximum value so that the drive current decreases, in response to the current value having reached the threshold. The controller subtracts, from the control parameter, the correction value calculated, thereby correcting the control parameter. The controller drives the motor based on the control parameter corrected.