Abstract: The invention relates to a discontinuous clamping wrench, of the type comprising a motor and a pulse clutch integrated in a casing, characterised in that it comprises measurement means of dynamic phenomena induced by said clamping on said casing, with a view to correlating said measurement with a clamping level.

Abstract: The system is intended to block the tool operation for an operator holding a badge the authorized working time of which is over. The system comprises: the operator badge, comprising a storage memory for the working time carried out by the operator and a communication unit; the tool, comprising an accelerometric sensor and a housing for control and vibratory traceability comprising a communication module, arranged to exchange data with the operator badge and means for blocking the tool operation. For the vibratory charge traceability of the tool, in the tool, the accelerations experienced by the tool while operating and its corresponding working times, forming traceability data, are measured; the traceability data in the tool are saved; the traceability data are transmitted to an operator personal badge.

Abstract: A discontinuous drive power tool assembly for generating rotational torque includes a spindle having a first end portion and a second end portion. The first end portion of the spindle is configured to engage and rotate an object. The tool assembly also includes a pulse hammer selectively engagable with the second end portion of the spindle, and a motor that includes a motor shaft engagable with the pulse hammer. The motor is configured to rotate the pulse hammer. The tool assembly also includes a rotational position sensor disposed adjacent the motor. The rotational position sensor is configured to measure the rotational position of a second portion of the motor shaft which is opposite the first end portion of the motor shaft during operation of the tool assembly.

Abstract: A rotary tool includes an externally operable operation switch; a motor serving as a power source; a power transfer block for transferring the rotation of the motor; a load detection unit for detecting an amount of load of the motor; and a control unit for controlling the motor. The control unit is configured to perform an operation control by which the motor is controlled so that a rotation speed of the motor is increased in proportion to the operation amount of the operation switch and a feedback control by which the rotation speed of the motor is controlled depending on the detection result of the load detection unit. The control unit inhibits the feedback control during the time when the operation amount of the operation switch is equal to or less than a threshold and performing the feedback control only when the operation amount of the operation switch is greater than the threshold.

Abstract: A power tool, such as a hammer drill and/or a chiseling hammer, includes a lubricated transmission arranged in a sealed transmission box. The transmission box is in fluid connection with the atmosphere via a venting channel. A sealing element is arranged in the venting channel. The sealing element cooperates with the venting channel to create a meandering pathway for air to pass through the venting channel so that leakage of lubricant between the sealing element and the venting channel is at least substantially prevented.

Abstract: An effective technique for detecting several load conditions different in presence or absence and magnitude of load applied to a tool bit is provided in a hand-held tool. A hand-held tool 101 performs a predetermined operation while pressing a tool bit 119 mounted in a front end region of a tool body 103 against a workpiece. A plurality of detecting sensors 161 of different kinds detect several load conditions different in presence or absence and magnitude of load applied to the tool bit 119. The hand-held tool 101 includes at least one of an indicating device 171 which indicates the load conditions based on a result detected by the detecting sensors 161, and a driving control device 135 which controls driving of the tool bit 119 based on the detected result.

Abstract: The invention is based on a handheld power tool device, having at least one safety mechanism, which intervenes in an uncontrolled blocking situation, and which has a sensor unit. It is proposed that the sensor unit is provided for directly detecting at least one orientation parameter of a handheld power tool.

Abstract: Power tools are taught that may include, for example, means for detecting impact sounds generated, e.g. by a hammer strikes an anvil or by oil pulse from an oil unit. The detecting means may include a receiver (30) adapted to selectively convert sound within a narrow frequency range into electric signals. Preferably, the impact sounds fall within the narrow frequency range of the receiver (30). A processor 38 may be utilized to control the motor (22) in order to stop the rotation of the hammer when a pre-determined number of impact sounds has been detected by the detecting means. In addition or in the alternative, various means for setting various operating conditions are taught, including dials 34, sound sensors 30, keypads and remote control devices 250. Further, means for performing maintenance condition status checks are taught.

Abstract: An improved method is provided for controlling a power tool having a rotary shaft. The method includes: disposing an inertial mass in a housing of the power tool, such that the inertial mass is freely rotatable about an axis of rotation which is axially aligned with the rotary shaft; monitoring rotational motion of the power tool in relation to the inertial mass during operation of the power tool; and activating a protective operation based on the rotational motion of the power tool in relation to the inertial mass.

Abstract: A device for impacting a fastener in one embodiment includes a lever arm pivotable between a first position whereat a flywheel is spaced apart from a drive mechanism and a second position whereat the flywheel can contact the drive mechanism, a motor operably connected to the flywheel for storing energy in the flywheel, a trigger sensor assembly for generating a trigger signal indicative of the position of a trigger, a work contact element (WCE) sensor for generating a WCE signal indicative of the position of a WCE, a memory including program instructions, and a processor operably connected to the memory for executing the program instructions to (i) energize the motor based upon the WCE signal, and (ii) pivot the lever arm based upon the trigger signal.

Abstract: A portable power drill comprises a housing, a drilling implement carrying drive spindle, and two individually powered and controlled motors for rotating and axially feeding the drive spindle. The drive spindle is rotative and axially displaceable relative to the housing and connected to the drive and feed motors via angle gears including two bevel gears supported on the drive spindle. The feed via an axially locked but rotative nut piece and an external thread on the drive spindle, whereas the drive motor is drivingly connected to the drive spindle via longitudinal keyways on the drive spindle and mating splines in one of the bevel gears. The drive motor and the feed motor are electric motors controlled and monitored by a programmable control unit.

Abstract: According to an aspect of the present invention, there is provided a rotary striking tool, including: a motor; an impact unit having a driving part being driven by the motor and an output part; a tip-tool side output shaft that is coupled to the output part; an impact detection unit that detects an impact generated at the impact unit; and a control unit programmed to: control the impact unit to perform a confirmation striking when the impact detected by the impact detection unit reaches a prescribed value, detect a rotation angle of the output shaft at the confirmation striking, determine whether a fastening operation is completed when the detected rotation angle is equal to or smaller than a predetermined angle, and continue the fastening operation when the detected rotation angle is larger than the predetermined angle.

Abstract: An electric assembly device for tightening of fastener includes a housing and a rotation motor which is drivingly connected to an output shaft. The output shaft has a forward portion extending out of the housing, and is adapted to carry a coupling device for releasable coupling with a fastener during tightening, which is to be performed along a first rotation axis. The device is adapted to determine an angular displacement of the housing with respect to the first rotation axis during tightening of the fastener, and to control the rotation speed of the motor during tightening based on the determined angular displacement of the housing.

Abstract: According to an aspect of the present invention, there is provided a rotary striking tool includes: a motor; an oil pulse unit that is driven by the motor; an output shaft that is coupled to the oil pulse unit so that a tip tool can be attached to the output shaft; a first detection unit that detects a rotation angle of the motor and outputs a first output signal; a second detection unit that detects an impact generated at the oil pulse unit and outputs a second output signal; and a control unit that controls a rotation of the motor, wherein the control unit uses a portion of the second output signal based on the first output signal for control of the rotation of the motor.

Abstract: A Single Piezo-Actuator Rotary-Hammering (SPaRH) Drill includes a horn actuator having high power piezoelectric materials and a flexure pre-stress to increase the actuators effectiveness. The drill is a low mass, low power, compact coring drill measuring 20-cm high by 7-cm diameter and having a total weight of 2 kg including drive electronics. Using an average power of 50-Watts, the drill basalt is expected to cut basalt at a rate of 0.2 cm/min down to depth of 10-cm and create cuttings and an intact core. The drill is expected to operate under different environments including Martian ambient (6 Torr and down to ?50° C.), and liquid nitrogen temperatures (77 K) and low pressure (<<1 Torr) to simulate lunar polar and Europa conditions. Materials expected to be sampled include Kaolinite, Saddleback Basalt, Limestone, Volcanic Breccia, Siltstone, ice, permafrost and layered rocks with different hardness.

Abstract: Power tools are taught that may include, for example, means for detecting impact sounds generated, e.g. by a hammer strikes an anvil or by oil pulse from an oil unit. The detecting means may include a receiver (30) adapted to selectively convert sound within a narrow frequency range into electric signals. Preferably, the impact sounds fall within the narrow frequency range of the receiver (30). A processor 38 may be utilized to control the motor (22) in order to stop the rotation of the hammer when a pre-determined number of impact sounds has been detected by the detecting means. In addition or in the alternative, various means for setting various operating conditions are taught, including dials 34, sound sensors 30, keypads and remote control devices 250. Further, means for performing maintenance condition status checks are taught.

Abstract: A transmission assembly for a power tool comprises a first transmission path comprising a high speed transmission path and a second transmission path comprising a low speed transmission path. Driven gears of each transmission path are permanently driven during operation of the transmission. A controller is provided for engaging or disengaging the high speed transmission path in response to monitored operating current of an electric motor providing a driving torque to an input of the transmission. When disengaged, a driven gear of the high speed transmission path continues to be driven, but the driven gear is disengaged from an output of the transmission. Consequently, under these circumstances, the low speed transmission path is the ‘active’ transmission path providing a low speed, high torque drive to the transmission output.

Abstract: A power tool comprising a housing, a motor, an output shaft, a gear transmission mechanism and a control system. The gear transmission mechanism is connected between the motor and the output shaft to transmit the rotary power of the motor to the output shaft. The gear transmission mechanism has a high speed position and a low speed position. The control system is coupled to the gear transmission mechanism for detecting an operating characteristic of the power tool to actuate a ring gear to automatically move from the high speed position to the low speed position and to reduce the rotational speed of the ring gear when the operating characteristic exceeding a predetermined value.

Abstract: A force-limiting clutch for a surgical instrument includes a drive element and a transmission element. An actuator is coupled to the drive element, and a drive shaft is coupled to the transmission element for providing an output force. If the force input from the actuator to the clutch reaches a predetermined threshold, the force-limiting clutch “slips” and does not transfer the actuator force to the drive shaft to prevent excessive force/pressure output. Normally, drive features on the drive element engage with transmission features on the transmission element to transfer forces from the actuator to the drive shaft. When a threshold force is reached, the drive features slip past the transmission features. This clutch “breakpoint” determines the maximum loading that the surgical instrument can provide at its output. In various embodiments, multiple transmission features can be arranged in a serial manner, such that the force-limiting clutch provides multiple breakpoints.

Abstract: A power tool 1 is connected to a battery pack 5 including an overcurrent detector 533 which detects overcurrent of a battery module 51 and outputs a detection signal, and an overdischarge detector 532 which detects overdischarge of the battery module 51 and outputs a detection signal. The power tool 1 includes a motor 2 which is driven by electric power supplied from the battery pack 5, a trigger switch 31 for setting the power supply from the battery pack 5 to the motor 2 in ON/OFF state, and an FET 410 which sets the power supply to the motor 2 in ON/OFF state on the basis of the detection signal from the overcurrent detector 533 or the overdischarge detector 532.

Abstract: A method of operating a hand power tool in one embodiment includes generating a variable speed control signal with a solid state switch that corresponds to a selected speed for a motor, generating a pulse width modulated (PWM) signal corresponding to the variable speed control signal, generating H-bridge driving signals for an H-bridge circuit in correspondence with the PWM signal, and selectively coupling a motor to a power source using the H-bridge circuit in accordance with the H-bridge driving signals.

Abstract: A current detection circuit (18) detects that a drive current of the stator coil (2d) is exceeding a threshold value Ir. A rotation number detection circuit (17) detects that the number of rotations of a rotor (2a) is lower than a threshold value Nr. A computing part (20) outputs a PWM signal which switches a semiconductor switching element (3a) of the inverter circuit part (3). The computing part (20) changes the threshold values Ir and Nr in accordance with the PWM duty of the PWM signal determined in accordance with a pressed distance of a switch trigger (7) and detects a locked state of the motor (2) on the conditions that the motor current I is exceeding the set threshold value Ir and that the number of rotations N thereof is lower than the threshold value Nr.

Abstract: A power tool system includes a two-handed power tool having first and second start actuators, one for each hand of an operator. A controller prevents the power tool from initiating an operating cycle unless both actuators are turned ON to reduce the possibility of the operator's hands being disposed in a hazardous position during operation of the power tool. To discourage manual override of the dual-start-switch system, the controller prevents the power tool from initiating an additional operating cycle until both actuators have been switched OFF and then ON again. The second actuator includes a tubular sleeve that extends over part of the power tool to allow the sleeve to slide axially relative to the power tool between ON and OFF positions. Axial movement of the sleeve from its OFF position to its ON position turns ON the second start actuator.

Abstract: A method for producing Shockwave pulses in a tool direction (R) of a pulse machine (1) having a housing (2), wherein an impulse piston (4) is arranged, wherein the impulse piston is influenced by a first force in a direction opposite to said tool direction through a first fluid pressure (Pi) in a first chamber (7), and by a second force in said tool direction, wherein a Shockwave pulse is produced through a rapid relief of the first fluid pressure after displacement of the impulse piston (4) relative to the housing in a direction opposite to the tool direction, is distinguished in that the length of the shock wave is controlled by the length (L) of said displacement is regulated. The invention also concerns a device, rock drilling machine and a rock drilling rig.

Abstract: A system and method of tracking location and orientation of power tools utilized in the assembly and maintenance of complex systems is disclosed. The system can facilitate collaboration between maintenance and alert maintenance personnel to complete complex system activities.

Abstract: A bolt is fastened up to a predetermined snug torque Ts and then the bolt is further fastened by a specified angle ?t from a bolt angle corresponding to the snug torque Ts. Herein, in order to obtain excess and deficiency of the fastening angle up to the snug torque Ts, an angle-variation difference between the fastening angle ?sb of the bolt at the point where the fastening torque of the bolt has reached the snug torque Ts and a standard angle ?sa of the snug torque Ts is calculated. And, addition of this angle-variation difference to a base angle is set as the new specified angle ?t to correct the excess and deficiency. Accordingly, variation in a fastening shaft force can be restrained even if the snug torque is set at a relatively high torque in the bolt fastening method using the torque+angle method.

Abstract: An improved method is provided for controlling a power tool having a rotary shaft. The method includes: disposing an inertial mass in a housing of the power tool, such that the inertial mass is freely rotatable about an axis of rotation which is axially aligned with the rotary shaft; monitoring rotational motion of the power tool in relation to the inertial mass during operation of the power tool; and activating a protective operation based on the rotational motion of the power tool in relation to the inertial mass.

Abstract: A power wrench includes a housing divided into two parts which are rotatable relative to each other: a first part including a handle and a transverse section lodging a rotation motor, and a second part including a reduction gearing, an output shaft and a rigidly attached and laterally extending reaction bar. A swivel connection is provided between the housing parts and includes an angle sensor arranged to generate signals in response to relative angular movements between the housing parts, and a power control unit communicates with the angle sensor and is arranged to at least substantially reduce the motor power as a pre-set maximum angular movement between. the housing parts is exceeded as the motor is started.

Abstract: An apparatus and method for preventing theft in automotive vehicle service centers. The apparatus includes at least one portable tool and a controller. The portable tool includes circuitry configured to communicate with the controller. The portable tool further includes anti-theft circuitry, which is configured to disable the portable tool if no communication occurs between the portable tool and the controller for a predetermined time period.

Abstract: An object is to improve accuracy of tightening torque and to shorten time necessary for fastening a screw in an impact type screw fastening device that uses an electric motor as a rotation driving source. A control method for the impact type screw fastening device that uses an electric motor as a rotation driving source includes the steps of driving the motor to rotate by supplying current to the motor intermittently so that torque exerted on a load by rotation of the motor becomes like pulses on the time axis, and controlling the current of every time of each pulse so that an increment of every time of each pulse of the torque after the torque reaches a target approach torque TQN that is a first set value becomes smaller than that before it reaches the target approach torque TQN.

Abstract: The present invention relates to a method, with which an electric power tool is operated, which comprises a drive motor, a drive unit as well as a tool, the tool being operated by means of the drive unit and the drive motor. Said tool can be operated in at least two operating modes, said operating modes varying due to the properties of the drive motor and/or the drive unit. The setting of at least one of the two operating modes occurs automatically. The present invention furthermore relates to an electric power tool, which particularly can be operated with the one method according to the invention, having a drive motor, a drive unit as well as a tool, said tool being operable in at least two operating modes by means of the drive unit and the drive motor. The operating modes vary due to the properties of the drive motor and/or the drive unit.

Abstract: An electric hammer comprising a hammer bit performing hammering work on a work, a drive motor, a hammering piece driven by the drive motor to apply a hammering force to the hammer bit, and a mechanism for damping vibration generated during hammering. The damping performance of the electric hammer is enhanced by causing the driving amount applied to the damping mechanism to vary between a first mode where the damping mechanism generates vibration of the hammer bit subjected to an external force from the work during the load driving time and thereby optimizes the damping and a second mode where the damping mechanism generates vibration corresponding to the vibration of the hammer bit not subjected to an external force from the work during the no-land driving time and optimizes damping.

Abstract: An improved method is provided for controlling a power tool having a rotary shaft. The method includes: disposing an inertial mass in a housing of the power tool, such that the inertial mass is freely rotatable about an axis of rotation which is axially aligned with the rotary shaft; monitoring rotational motion of the power tool in relation to the inertial mass during operation of the power tool; and activating a protective operation based on the rotational motion of the power tool in relation to the inertial mass.

Abstract: A tightening tool for tightening a fastener is disclosed which comprises a motor and a main shaft that engages with the fastener. A clutch is disposed between the motor and the main shaft so that the clutch rotates the main shaft by transmitting torque from the motor to the main shaft when a load acting on the main shaft is less than a predetermined value. The clutch shuts off torque transmission from the motor to the main shaft when the load acting on the main shaft reaches or exceeds the predetermined value. When in use, the current flowing to the motor and rotation angle of the main shaft of the motor are detected. The detected current and rotation angle are used to determine whether the tightening torque of the fastener is normal.

Abstract: This invention relates to the control of a machine for performing drilling or bolting operation, such as in an underground mine. In one aspect, the invention comprises a system including an input device for manually controlling at least one aspect of the drilling or bolting operation and a controller associated with at least one neutral switch. An actuator actuates the drilling or bolting operation and includes a valve associated with the input device and the neutral switch. The input device is operative for controlling the drilling or bolting operation only when the valve is in a neutral position according to the neutral switch. Related input devices and methods are also disclosed.

Abstract: A power tool includes an optical speed control switch for controlling the variable speed of an electrical motor in the tool. The tool includes a moveable member having a reflective surface and the moveable member traversing a distance between a stop position and a full speed position, a biasing member operatively coupled to the moveable member to bias the moveable member toward the stop position, an optical signal generator for generating an optical signal, the optical signal generator being oriented so that the optical signal is directed toward the reflective surface of the moveable member, and a speed control signal generator for generating a speed control signal that corresponds to a reflection of the generated optical signal reflected by the reflective surface of the moveable member.

Abstract: A hand power tool has a percussion mechanism; a drive motor that drives the percussion mechanism; a conversion element for converting a movement of the drive motor into an axial movement; and an operating unit that adjusts a rotary movement of the conversion element within a percussion period depending on at least one optimization criterium.

Abstract: An impact tool (100) includes a spindle (11), a motor (1), a rotational impact system (10), a current detecting unit (32), and a current control unit (31). The spindle extends in an axial direction thereof. The motor provides the spindle with a rotational power in accordance with a motor current flowing therethrough. The rotational power rotates the spindle about the axis at an rpm value. The rotational impact system provides the spindle with an impact force in the axial direction, thereby transmitting both the rotational power and the impact force to an end bit. The current detecting unit detects a current value of the motor current. The current control unit reduces the current value if the current value detected by the current detecting unit exceeds a predetermined value.

Abstract: A portable power tool, wirelessly communicates with a stationary process control unit for exchange of operation parameter values, includes a housing with a battery powered motor connected to an output shaft, an on-board operation controller, and a wireless communication device in the form of a communication module. The communication module is received in a docking portion on the housing, and the docking portion and the communication module have matching electrical connectors. The communication module is one of a number of exchangeable communication modules all having identical electrical connectors for co-operation with the connection of the docking portion but which include communication devices for wireless communication according to different communication systems.

Abstract: The invention relates to a power tool, which comprises a motor for driving a tool bit rotating, the motor attains a rotational speed, a source for supplying an electric current to said motor, a sensor for measuring said current, and a control device. The control device fulfills the task of detection of a variation of the slope of the current in the course of time, and generates a control signal. The rotational speed of the tool is reduced in response to the control signal. The present invention automatically detects whether the work piece operated by the tool bit reaches a predetermined position by providing electronic control means. It may make sure that the screw is driven into a piece of wood and does not go beyond the predetermined position once detect that the work piece reaches the position and carries out the changing action.

Abstract: An electric power tool includes a tool body and a battery pack. A terminal voltage setting unit of the tool body sets a voltage of a body side terminal to a first voltage when a command to drive a drive portion of the tool body is issued by a switch of the tool body. A voltage changing unit of the battery pack changes a voltage of a battery side terminal from the first voltage to a second voltage when supply of electric power from the battery pack to the drive portion is permitted.

Abstract: A method of driving a fastener into a workpiece with a tool generally includes retracting a trigger into a housing of the tool to execute a driver sequence and establishing a magnetic field in a multistage solenoid. The magnetic field is established in at least one of a first stage and a second stage. The method includes drawing an armature member to an extended condition from a retracted condition with the magnetic field and determining a position of the armature member relative to at least one of the first stage and the second stage. The method also includes directing power between the first stage and the second stage during the driver sequence based on the position of the armature member.

Abstract: A machine tool, in particular in a handheld configuration, that is equipped with tools for a sensory detection of a trajectory that serves as a guideline and is detected in characteristic values and read in, alternatively to a programmed trajectory. The characteristic values that are on a side of the machine tool are converted into control signals for a working line that is tracked mark-free.

Abstract: The invention discloses a power tool having a motor adapted to drive a tool, comprising at least one switching element, coupled with a controller, for actuation of the motor, the controller being configured so that the motor can be switched on for driving the tool only when the at least one switching element is activated several times in a predetermined way, or when at least two switching elements are activated simultaneously or in a predetermined way in succession, there being provided at least three operating modes, namely an inoperative mode, in which the motor is out of operation, a working mode in which the motor is driven for driving the tool, and an intermediate mode, in which the user is signaled that further activation of a switching element is needed for transferring the motor to its working mode.

Abstract: A method for controlling rock drilling and a rock drilling arrangement having at least one feed channel of a feed actuator provided with a restrictor, which causes a pressure drop if the penetration rate increases and, consequently, a flow through the restrictor increases. A pressure difference and an increase in the penetration rate can be detected by sensing the pressure before the restrictor and after the restrictor. When the feed rate increases, a hydraulic system is arranged to decrease percussion pressure.

Abstract: The invention relates to a method for correcting positioning errors in rock drilling, and a rock drilling equipment. Deviation of the boom position from the theoretical position is measured as a function of the position of at least one boom joint, the measured deviations are stored in the memory of the drilling rig, and when the boom is positioned to the drilling position, its position is corrected on the basis of the stored deviation. The drilling equipment includes a memory for storing the deviations between the true position of the boom and the theoretical position calculated on the basis of the joint sensor values, and a calculating device for correcting the boom position on the basis of the deviations stored in the memory of the drilling rig.

Abstract: A handle for an electric hand tool, which in use, is detachably connected to the hand tool as an auxiliary handle (2), includes at least one detection device (6), which communicates with at least one regulating and/or control element in the electric hand tool through a contactless signal transmission device.

Abstract: A device for sensing a direction of rotation of a hand tool having an electric motor, has a rotatably supported brush plate provided in the electric motor and located in different positions depending on a direction of rotation of the electric motor; and at least one sensor which senses the different positions of said brush plate to determine a direction of rotation, wherein said sensor is configured as a contactless sensor.

Abstract: A powered driver and methods are disclosed, the driver including a head having a gapped jaw and housing a motor driven drive transfer assembly for operating a rotatable split socket engageable at a threaded connector. A reaction unit is movably maintained through the head, and a probe is associated with the reaction unit. The methods of this invention include setting a selected rotational limitation at the driver relating to fitting characteristics, operating the driver to cause relative rotation of a connector nut located in the socket and connector body engaged by the reaction unit. One of a plurality of operational modes for driver operations is selected and relative movement of the head and reaction unit are monitored during driver operation. The driver is controlled so that driver operation ceases when a selected combination of events related to operational mode selected and at least one of rotational limitation setting, monitored relative movement or driver operation occurs.

Abstract: A fastening tool with a clutch for shutting off transmission of torque, capable of self-diagnosing fastening torque of a screw or the like at low cost without using expensive elements such as a torque sensor, etc. A fastening tool (10) has a motor (13), a main shaft (20) engaging with a screw or the like, and a clutch (14) interposed between the motor (13) and the main shaft (20). The clutch (14) transmits torque from the motor (13) to the main shaft (20) when a load acting on the main shaft (20) is less than a predetermined value, and shuts off torque transmission from the motor (13) to the main shaft (20) when a load acting on the main shaft (20) is equal to or greater than the predetermined value. The fastening tool (10) further has a control unit (60) for controlling the motor (13).