A rotary impact tool in one aspect of the present disclosure includes a motor, an impact mechanism, an impact detector, and a controller. The controller executes constant duty ratio control from when the motor is started until an impact is detected by the impact detector. The controller executes constant rotation speed control in response to detection of an impact by the impact detector.

An operation switch sends an ON signal to a control processor indicating the operation switch is triggered by a user. A magnetic sensor sends a sensor signal to the control processor based on a displacement of a chip rod in a rearward direction. In the case where the sensor signal has not yet been sent, the control processor performs a control in a first mode where a brushless DC motor is not driven. In the case where sensor signal is sent, control processor performs a control in a second mode wherein the brushless DC motor is driven. An output in the first mode is lower than in the second mode. Because of this manner of construction, even if an ON input is triggered and held by the user, electric power is conserved while the operation switch is switched on and a hexagonal nut is not fastened, improving power consumption efficiency.

A threaded member tightening tool for setting the length of drive time to elapse before rotation is switched from high-speed rotation to low-speed rotation. A motor-driven screwdriver system in which a screwdriver bit is first driven at a predetermined high rotational speed only for a high-speed drive time and thereafter driven at a predetermined low rotational speed lower than the high rotational speed. A control unit drive-controls an electric motor so that the screwdriver bit is rotationally driven at a setting rotational speed, measures a tightening time required until a Hall element detects that a threaded member engaged with the screwdriver bit has been tightened completely, calculates an initial setting time by multiplying the tightening time by a predetermined positive value less than 1 and a value obtained by dividing the setting rotational speed by the high rotational speed, and sets the high-speed drive time to the initial setting time.

An improved multi-bolt and nut torque wrench for installing and removing bolts or nuts from flanged joints or the like which includes a plurality of torque stations having a plurality of high torque wrenches for engaging the heads of the bolts or nuts during a high torque phase of removal or installation; a plurality of low-torque motors operatively engaged with the wrenches for rotating the bolts or nuts during the low torque phase of removal or installation; a source of hydraulic fluid for driving the low-torque motors during the low-torque phase, and driving the high-torque wrenches during the high torque phase; and a mechanism for switching between the two phases depending on the torque needed.

A fastening tool includes: a bit holding portion which detachably holds a driver bit and is configured to rotate in a circumferential direction of the driver bit and move in an axial direction of the driver bit; a first motor configured to rotate the bit holding portion; a second motor configured to move the bit holding portion along the axial direction; and a control unit configured to control a position of the bit holding portion along the axial direction by the number of rotations of the second motor. The control unit is configured to control a moving speed of a screw moved by rotation of the first motor or a rotation speed of the first motor.

A machine and a method for drilling a hole or setting a screw is provided, wherein the machine comprises a motor having a shaft and one or more magnetic coils, providing electric current to the one or more magnetic coils to rotationally drive the shaft, and switching the electric current at a commutation frequency to define a rotational speed of the shaft. A signal may be generated when a force towards the machine applied to the shaft increases and/or a torque applied to the shaft increases and the rotational speed of the motor may be increased to a first rotational speed when the signal is received. The rotational speed may be at least 6,800 RPM and at most 8,500 RPM.

The present invention discloses a speed changing tool, comprising: a housing; a motor, disposed in the housing and outputting rotary power; a trigger switch, used for starting and stopping the motor; an output shaft; a gear transmission, which is disposed between the motor and the output shaft to transmit rotation of the motor to the output shaft, and comprises at least one group of gear system, a gear ring meshed with the gear system and a moving member, wherein the moving member can be moved between a first position and a second position and when in the first position and the second position, the moving member has different states relative to the housing, such that the gear transmission outputs a rotary speed of the motor with different speed reduction ratios; the variable speed tool further comprises a drive mechanism for driving the moving member to move between two positions, when a load of the output shaft reaches or exceeds a preset value, the drive mechanism can drive the moving member to move to the second position from the first position, the trigger switch can push the drive mechanism to drive the moving member to move to the first position from the second position when the trigger switch comes back from a work position to an original position.

A control method according to an aspect of the invention includes a process for setting target fastening torque, a pulse interval of neighboring pulses, and an elevated value of torque per pulse, detecting last fastening torque at an Nth pulse (N is a natural number of 1 or more) after seating of a fastening member, setting pulse loading time at an N+1th pulse and pulse strength at the N+1th pulse based on the last fastening torque at the Nth pulse so that fastening torque at the N+1th pulse coincides with a multiple of the elevated value, controlling a fastening tool based on the pulse interval, the pulse loading time, and the pulse strength so that last fastening torque at an N+Mth pulse (M is a natural number of 1 or more) reaches target fastening torque.

An electric work machine includes: a motor; a first planetary gear mechanism; a second planetary gear mechanism; a spindle; a first speed switch mechanism including a first internal gear of a first stage unit and a second internal gear of a second stage unit; and a second speed switch mechanism. The first speed switch mechanism performs switching between a first speed reducing mode in which rotation of the second internal gear is prevented and rotation of the first internal gear is allowed and a second speed reducing mode in which rotation of the first internal gear is prevented and rotation of the second internal gear is allowed. The second speed switch mechanism performs switching between an enabled mode in which rotation of an internal gear of the second planetary gear mechanism is prevented and a disabled mode in which the rotation of the internal gear is allowed.

A method is provided for setting a fastener in a workpiece. The method includes: monitoring a parameter of the power tool during operation of the power tool, where the parameter is indicative of the placement of a fastener being driven by the power tool in relation to the workpiece; detecting, a change in the parameter, where the detected change in the parameter indicates that the power tool became disengaged with the fastener; modifying operation of the power tool in response to the detected change in the parameter; subsequently detecting a second change in the parameter; and interrupting transmission of torque to the output spindle in response the detected second change in the parameter, thereby properly setting the placement of the fastener in relation to the workpiece.