Abstract: The disclosure provides a method, device and equipment for monitoring screwing. The method for monitoring screwing comprises: obtaining an air pressure value in an air supply line; the air supply line being used to supply air to a pneumatic screwdriver to trigger the pneumatic screwdriver to perform a screwing operation; determining a target monitoring value according to the air pressure value; wherein the target monitoring value comprises at least one of: an initial air pressure value when the pneumatic screwdriver starts performing the screwing operation; a lower air pressure limit value when the pneumatic screwdriver performs the screwing operation; a working time of the pneumatic screwdriver for performing the screwing operation; judging whether the target monitoring value conforms to a corresponding predetermined range value and obtaining a judgment result; determining, based on the judgment result, whether the pneumatic screwdriver performs the screwing operation properly.

Abstract: The electric screwdriver apparatus control method is executed by an electric screwdriver apparatus. A processing module of the electric screwdriver apparatus loads a configuration data, and the processing module controls a motor module to accelerate a rotational speed to a target rotational speed. When a revolution number exceeds a first revolution number, the processing module controls the motor module to decelerate to a first rotational speed. When a torque value exceeds a first torque value, the processing module determines whether a fastening process of a screw ends with a hard stop or a soft stop according to the configuration data. If the fastening process ends with the hard stop, then the screw is additionally tightened for a hard stop angle, vice versa. The processing module tightens the screw according to the configuration data, the torque value and a rotational speed value, improving the process of fastening the screw.

Abstract: A flywheel device is adapted to be installed in an electric nail gun. The electric nail gun includes a main frame, a drive pulley rotatably mounted to the main frame, and a transmission belt. The flywheel device includes a flywheel pulley adapted to be mounted to the main frame, a flywheel connected coaxially and co-rotatably to the flywheel pulley, and a weight disc connected coaxially and co-rotatably to the flywheel and the flywheel pulley. The transmission belt is trained on the drive pulley and the flywheel pulley. During co-rotation of the flywheel pulley, the flywheel and the weight disc, a swing arm is pivotable to move an impact member to contact the flywheel for actuating a nailing process of the electric nail gun.

Abstract: An electric working machine in one aspect of the present disclosure includes a motor, a setter, and a controller. The setter is configured to modifiably set a change characteristic in changing a rotational state of the motor from a low speed rotation to a high speed rotation. The high speed rotation is greater than the low speed rotation in rotational frequency of the motor.

Abstract: A method detects whether a fastener is already tightened using a tightening tool with a pulse mechanism. The method includes placing the tightening tool on the fastener, and accelerating rotational parts of the tightening tool. The rotational speed of the rotational parts is limited to a first rotational threshold value in revolutions per minute during an initial tightening phase, the first rotational threshold value being set to be in a range of 20% to 80% of a second rotational threshold value in revolutions per minute needed in a secondary tightening phase to provide a target fastening value for the fastener. And it is detected whether a pulse occurs during the initial tightening phase, the initial tightening phase being measured from a moment when the rotational parts are accelerated.

Abstract: In a nut runner with a motor (3) for generating a torque, a tool holder (9) which is operatively connected with the motor (3) and transmits the generated torque to a tool, a measuring device (7) which continuously measures at least one measurement quantity for determining the torque and forwards the measurement value, and a control device (12) which is connected with the motor (3) and the measuring device (7) and controls the operation of the motor (3) such that after starting it generates a continuously increasing torque, and which shuts off the motor upon reaching a setpoint measurement value, the measuring device is a torque sensor (7) and the torque sensor (7) is arranged between the motor (3) and the tool holder (9).

Abstract: A client computing system (CCS) receives a tool measurement from a measurement tool other than by determining the tool measurement from a vehicle data (VD) message. The CCS generates a VD report including a vehicle identifier of a vehicle associated with the tool measurement and the VD report. The VD report can include temporal and/or spatial identifiers pertaining to the tool measurement. The VD report can be provided to a server computing system (SCS) for storage as part of a VD record associated with the vehicle. The CCS that generated the VD report or another CCS can request the VD report from the SCS. The SCS can determine if the requesting CCS is authorized to receive the VD report to maintain the vehicle owner's privacy. The tool measurement can be selected from a service procedure provided to the CCS from SCS and displayed at the CCS.

Abstract: An electric power tool in one aspect of the present disclosure comprises a main body, a motor, a driver, a detector, and a kickback determiner. The kickback determiner determines that the main body is kicked back from a workpiece when an attitude change amount of the main body detected by the detector exceeds a preset kickback determination threshold during driving of the motor by the driver.

Abstract: A system for use in a mineral extraction system includes a spinner assembly having a motor configured to drive rotation of a roller shaft. The spinner assembly also includes a roller non-rotatably coupled to the roller shaft and configured to contact a first tubular structure, and rotation of the roller is configured to cause rotation of the first tubular structure until the first tubular structure is spun into a second tubular structure. The spinner assembly further includes a detection wheel coupled to the roller shaft and configured to contact the first tubular structure, and the detection wheel is configured to rotate with the first tubular structure and to rotate independently of the roller. The spinner assembly further includes a sensor configured to detect rotation of the detection wheel.

Abstract: A torque wrench for applying a torque to a fastener includes a handle, a user interface carried by the handle, and a fastener drive. The fastener drive can be detachably engaged with the handle and also include a head shaped to receive a fastener. The user interface can indicate an applied torque on the fastener.

Abstract: A power tool includes a motor, a power circuit coupled to the motor, and a speed sensor coupled to the motor. The power circuit provides power to the motor. The speed sensor detects a position of the motor. The power tool also includes an electronic processor coupled to the motor and the speed sensor. The electronic processor is configured to receive an output signal from the speed sensor indicative of a measured speed of the motor at a first time, determine a cumulative value based on the measured speed of the motor, and interrupt power from the power circuit to the motor when the cumulative value exceeds an accumulator threshold.

Abstract: The disclosure is based on a sensor device, in particular a hand-held power-tool sensor device, for identifying an uncontrolled occurrence of jamming in the case of a hand-held power tool, having at least one sensor unit, which is provided to sense at least one motion characteristic value of the hand-held power tool, and having a protective unit, which is provided to control the hand-held power tool in dependence on at least one triggering threshold value and the at least one motion characteristic value. It is proposed that the protective unit be provided to set the at least one triggering threshold value in a variable manner and/or to define at least one further triggering threshold value.

Abstract: A method is presented for controlling operation of a power tool having an electric motor drivably coupled to an output spindle. The method includes: receiving an input indicative of a clutch setting for an electronic clutch, where the clutch setting is selectable from a plurality of driver modes; setting the value of a maximum current threshold in accordance with the selected one of the plurality of driver modes; determining rotational speed of the electric motor; determining an amount of current being delivered to the electric motor; comparing the amount of current being delivered to the electric motor to the maximum current threshold; and interrupting transmission of torque to the output spindle when the amount of current being delivered to the electric motor exceeds the maximum current threshold and the rotational speed of the electric motor is decreasing.

Abstract: An electric working machine including: a motor; a driving unit configured to be driven by the motor; a trigger switch configured to allow rotation of the motor; a power supply unit configured to supply electric power to the motor; and a control unit configured to control rotation of the motor, characterized in that: the electric working machine further comprises a switching element configured to perform short-circuiting between terminals of the motor to apply electronic braking, wherein the control unit is configured to perform adjustment of the braking by controlling the switching element when stopping the motor.

Abstract: An electric boring tool comprises an electric motor, a switch trigger, a tip tool driven by driving force of the electric motor, a power transmission mechanism for transmitting the driving force of the electric motor to the tip tool as rotational force and/or hammer force, and a motor control unit for controlling speed of the electric motor in response to an extent of pulling of the switch trigger. The motor control unit subjects the electric motor to low speed control after the electric motor is started up, and controls the speed of the electric motor in response to the extent of pulling of the switch trigger when the load current of the electric motor is set value or greater during the low speed control.

Abstract: A power wrench with a torque sensing unit includes a housing, a motor, an output shaft, and a planetary reduction gearing connecting the motor to the output shaft and including a stationary ring gear supported in the housing, wherein the torque sensing unit includes a torque transferring element with a single radially extending reaction arm arranged to transfer reaction torque from the ring gear to the housing and carrying strain measuring sensors for generating signals in response to the transferred reaction torque. The torque transferring element includes an annular body with two weak portions to be elastically deformed during torque transfer and having flat surfaces for carrying the strain measuring sensors.

Abstract: A torque applying system includes a torque applying tool having a motor and rotating output spindle, a torque sensor that measures an instantaneous torque exerted by the output spindle during a fastening cycle, and a controller operatively connected to the tool to control the tool's rotational speed during the fastening cycle. The controller is programmed to control the tool's rotational speed to be [(?F??C)/t]/r, wherein t is a time constant of speed control, ?F is a target final torque for the fastening cycle, and r is a torque rate.

Abstract: A power tool includes a motor having an output shaft that defines an axis, a drive train connected to the output shaft and operable to drive a tool output and a housing at least partially surrounding the motor and the drive train. The power tool further includes a reference disk fixed to the housing, a collar including internal teeth that engage at least a portion of the drive train and a torque transducer having a hub, a web and a rim. The torque transducer is positioned between the collar and the reference disk such that the rim is connected to the collar and the hub is connected to the reference disk. The web defines a first thickness measured parallel to the axis and the rim defines a second thickness measured in a radial direction with respect to the axis, such that the second thickness is greater than the first thickness.

Abstract: A power screwdriver is disclosed, having a drive for driving a tool spindle having a controller for controlling the drive, having a monitoring device for monitoring the rotation speed or the torque, and having a monitoring device for monitoring a switch-off criterion, which monitoring device is coupled to the controller, in order to switch off the drive when the switch-off criterion is reached, with the controller being programmed such that (a) the drive is first of all accelerated until the rotation speed has reached a specific first rotation speed; (b) if the rotation speed then falls by at least a specific amount within a specific time increment, or the torque rises by at least a specific amount within a specific time increment, the drive is braked until the rotation speed has reached a specific second rotation speed, which is lower than the first rotation speed; (c) the drive is then regulated at the second rotation speed for a specific time; and (d) after step (c), the drive is accelerated again at most

Abstract: A power tool has a motor, a power supply unit, a trigger unit, a control unit, and a motor load detection unit. The power supply unit supplies power to the motor. The trigger unit causes the power supply unit to start applying a voltage to the motor. The control unit controls the power supply unit to increase the voltage to the motor at a constant increasing rate. The motor load detection unit detects a motor load. The control unit changes the constant increasing rate in accordance with the motor load.

Abstract: A power tool has a continuously variable transmission, a condition detection device, and an operation control device. The continuously variable transmission changes a velocity of a rotational output from a drive motor and outputs the rotational output to a spindle to which a tip end tool is mounted. The condition detection device detects a condition of the power tool. The operation control device determines a target RPM of the spindle based on the condition of the power tool detected by the condition detection device, and controls an RPM of the drive motor and/or a transmission gear ratio of the continuously variable transmission based on the target RPM.

Abstract: Disclosed is a medical driving device having a first motor coupled to a region of a first drive shaft; a second motor coupled to a second drive shaft; a coupler coupled to the second drive shaft and interchangeably connected to a working tool; a tool guide assembly comprising a tool guide surrounding the working tool and a surface guide having a distal region configured to couple to the tool guide and a proximal region configured to couple to the first motor, wherein the first motor causes axial motion of the tool guide assembly to a retracted state and drives a length of the working tool into a target region of a bone; a torque sensor configured to sense torque in at least the second motor by continuously measuring current used to drive the second motor; and programmable electronics package to keep RPMs constant. Related methods, systems, and/or articles are described.

Abstract: An electric screwdriver includes a housing, a motor having a rotor and a maximum torque at constant speed of Cmax, and an end member. A transmission drives the end member and has a reduction gear coupled to the motor and having a ratio R and an efficiency ?. A torque sensor detects an attainment of a set value torque Cc. A motor driver drives the motor with a series of electric current impulses, The transmission enables an accumulation of kinetic energy Ec in the rotor and a restitution to the end member of the kinetic energy Ec between two impulses from the motor driver. The motor and reduction gear are configured such that: R*?*Cmax<Cc, the set value of torque Cc being attained through the transfer of kinetic energy Ec to the end member, wherein ratio R is smaller than or equal to 10/(?Cmax).

Abstract: An impact rotation tool includes a drive source that generates power. An impact force generation unit generates impact force by changing the power generated by the drive source to pulsed torque. A shaft transmits the pulsed torque to the distal tool with the generated impact force. A torque detector generates a signal corresponding to the torque applied to the shaft. A determination unit determines whether or not a torque value obtained from a signal corresponding to the torque has reached a predetermined torque value. A control unit controls the drive source to a predetermined driving state when the determination unit determines that the torque value has reached the predetermined torque value. The determination unit is arranged on the shaft.

Abstract: A power tool includes a housing, a motor, an output member driven by the motor, and a reaming attachment coupled to the output member. The reaming attachment has a front end portion selectively driven in rotation by the output member to drive a fastener into a workpiece, and a reaming portion selectively driven in rotation by the output member to remove material from an end surface of a conduit. A rotational motion sensor in the housing is operable to detect rotational motion of the housing about an axis. A controller receives a signal indicative of rotational motion from the sensor, determines a direction of the rotational motion of the housing, and drives the motor in a direction corresponding to the direction of rotational motion of the housing.

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 torque applying system includes a torque applying tool having a motor and rotating output spindle, a torque sensor that measures an instantaneous torque exerted by the output spindle during a fastening cycle, and a controller operatively connected to the tool to control the tool's rotational speed during the fastening cycle. The controller is programmed to control the tool's rotational speed to be [(?F??C)/t]/r, wherein t is a time constant of speed control, ?F is a target final torque for the fastening cycle, and r is a torque rate.

Abstract: A rotary impact tool includes: a hammer rotating by receiving a rotational force of a motor; an anvil rotating by receiving a rotational force of the hammer; and an end tool attached to the anvil, the rotary impact tool being constructed such that when a torque of a value not less than a predetermined value is applied to the anvil from the outside, the hammer is disengaged from the anvil to rotate idle and applies an impact to the anvil in a rotational direction after rotating idle by a predetermined angle, the rotary impact tool including an impact detector configured to detect impacts and a speed switching device configured to switch the rotational speed of the motor, and when the impact detector detects an impact during rotation of the anvil in a tightening direction, the speed switching device switches the rotational speed of the motor from a normal speed to a low speed.

Abstract: A method of operating a rotary tool driven by a brushless motor including a DC brushless motor for rotationally driving a rotary bit, a torque setting clutch mechanism, a drive switch for drive-controlling a drive control circuit of the brushless motor, and a control means to rotationally drive the brushless motor by an operation of the drive switch and wherein the method includes a first step for stop-controlling of the drive control circuit, a second step for rotating forward or in reverse the brushless motor through the control and a third step for control-operating a semiconductor of an inverter circuit provided in the drive control circuit to short-circuit the magnetizing windings of the brushless motor, thus braking the rotor of the brushless motor and stopping the brushless motor.

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 hand-operated rotary power tool and a method of operating the tool is disclosed. The tool has an electric motor for driving a rotary tool, a sensor device for detecting a blockade of the tool and a triggering device, which, in response to a blockade detected by the sensor device, reverses a direction of rotation of the electric motor prior to the blockade for a predetermined duration and immediately following induces the electric motor to again rotate in the direction of rotation.

Abstract: A power tool includes a bit mounting unit, a motor, and a control unit. The bit mounting unit is configured to mount thereon a bit. The motor is configured to rotatingly drive the bit. The control unit is configured to control a drive of the motor. The control unit includes a storing unit configured to store a plurality of prescribed values affecting the drive of the motor and a division number by which a range of the plurality of prescribed values is divided. At least one of the range and the division number is arbitrarily settable.

Abstract: A power (1) tool including a driven member (15) that is operable to grip and drive at least one working element (4), drive means (25) operable to drive the driven member, the power tool being operable in either a working mode in which the driven member is driven to enable the working element to perform work, or an adjustment mode in which the driven member is adjusted to grip or release the working element, torque control means (7) controlling the torque produced by the drive means, the torque control means being operable to render the drive means inoperable when the torque exceeds a pre-determined level, the torque control means having an adjustment setting (17) which must be selected to enable the power tool to operate in an adjustment mode whereby the adjustment setting corresponds to a relatively low level of torque.

Abstract: An improved method is provided for operating a power tool. The method includes receiving an input control variable from an input unit; receiving at least one tool parameter relating to the power tool; determining a derivative of the input control variable; selecting one of a plurality of control profiles based on the control input variable, the derivative of the input control variable, and the tool parameter, each control profile correlating the control input variable of the input unit to a rotational speed at which to drive the output shaft; and driving the output shaft at a rotational speed in accordance with the selected control profile.

Abstract: An impact wrench which includes an air motor and a main shaft that is rotated by pulsed impact torque that is converted from rotary torque from the air motor to tighten a bolt, is provided with a torque sensor that detects a tightening torque on the bolt, and a controller that performs control functions to tighten the bolt, and the controller changes the rotational speed of the air motor to tighten up the bolt when the tightening torque that is detected by the torque sensor becomes equal to or higher than a prescribed value.

Abstract: The invention is based on a device for handheld power tool for detecting a torque, having at least one sensor unit. It is proposed that the sensor unit is intended for detecting a deformation parameter. The sensor unit has at least one sensor element that is embodied as a strain gauge. A gearbox is provided which has a bearing location for receiving a deformation element of the sensor unit. An electronic unit evaluates detected data from the at least one sensor unit.

Abstract: A hand-held power tool comprises a motor, an output section which is rotationally driven by the motor, and an output change section which changes the output of the output section in a stepless manner while normally driving the motor. The hand-held power tool is improved so that the output of the output section during working can be smoothly controlled.

Abstract: In a pneumatic impact wrench there is an output shaft that is connectable in a removable manner to a screw coupling member; a torque sensor, which is mounted on the shaft, sends signals to a control unit that calculates the energy transferred through the output shaft and controls the wrench on the basis of a comparison between the calculated energy and a predefined threshold value.

Abstract: Provided is a power tool which is capable of more reliably detecting excessive reaction torque acting on a tool body. More specifically, provided is a handheld power tool which causes a tip tool to rotate so as to carry out a predetermined machining operation, the handheld power tool comprising a tool body, a motor which is housed in the tool body and causes the tip tool to rotate, a first sensor which detects the torque state of the tip tool, a second sensor which detects the motion state of the tool body, and a torque cut-off mechanism which cuts off the transmission of torque between the motor and the tip tool. The torque cut-off mechanism is configured to cut off the transmission of torque on the condition that the first sensor and the second sensor respectively detect a preset threshold value for the first sensor and the second sensor.

Abstract: A system, and a method of using a system, for controlled tool operation. The method includes providing a tool used in a force application such as a such torque application. The tool communicates with a controller which can communicate with the tool, and to a display in communication with the tool and the controller. The controller can be programmed with operational information about a tool operation. Information related to the operational information is displayed to a user during use. Service information including at least information about an amount of force applied during use is recorded and stored in the controller. Also disclosed is a computerized system for controlled tool operation which sends operational instructions to the tool before use and retrieves service information from the tool after use.

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: The invention provides a transmission assembly and a power tool. One form of the power tool includes a rotatable driven member for releasably gripping and rotating a working element and a transmission assembly for transmitting rotation from a motor to the driven member. The transmission assembly includes a rotatable input shaft and first and second rotatable output shafts. In a first speed setting the input shaft is selectively lockable together with the first output shaft so that the locked input shaft and first output shaft rotate in unison to drive rotation of the driven member at a first speed of rotation relative to a speed of rotation of the motor. In a second speed setting the input shaft is selectively lockable to the second output shaft so that the locked input shaft and second output shaft rotate in unison to drive rotation of the driven member at a second speed of rotation relative to the speed of rotation of the motor.

Abstract: A power screwdriver is disclosed, having a drive for driving a tool spindle having a controller for controlling the drive, having a monitoring device for monitoring the rotation speed or the torque, and having a monitoring device for monitoring a switch-off criterion, which monitoring device is coupled to the controller, in order to switch off the drive when the switch-off criterion is reached, with the controller being programmed such that (a) the drive is first of all accelerated until the rotation speed has reached a specific first rotation speed; (b) if the rotation speed then falls by at least a specific amount within a specific time increment, or the torque rises by at least a specific amount within a specific time increment, the drive is braked until the rotation speed has reached a specific second rotation speed, which is lower than the first rotation speed; (c) the drive is then regulated at the second rotation speed for a specific time; and (d) after step (c), the drive is accelerated again at most

Abstract: A power tool that includes a housing assembly, a motor received in the housing assembly, a trigger, an output spindle, a transmission and a bearing. The transmission is received in the housing assembly and transmits rotary power between the motor and the output spindle. The transmission has an output planetary stage with an output planet carrier. The transmission also has a member that is axially movable between a first position, which causes the transmission to operate in a first speed ratio, and a second position in which the transmission operates in a second speed ratio that is different than the first speed ratio. The bearing is disposed radially between and engages both the housing assembly and the output planet carrier. The output spindle is at least partially received into the output planet carrier such that the bearing indirectly supports the output spindle.

Abstract: Disclosed is a method for screwing in and tightening a screw connection (1) to a predetermined tightened level (2), especially a predetermined torque level (2) or a predetermined pretension level, with the aid of a hand-held screwing tool (3) comprising a regulated drive unit (4) and/or control functionality, particularly an electric nut runner (3). A tightening phase (B-C-D), during which the screw head rests against the supporting surface (6) of the screw connection (1), starts following a screwing phase (A). In order to improve said method, the speed (N) of the screwing tool (3) is increased to an output speed (7) for the tightening phase (B-C-D) within an acceleration time (8) in the tightening phase (B-C-D) and is lowered within a delay time (9) prior to or until reaching the predetermined tightened level (2).

Abstract: According to an aspect of the invention, an oil pulse tool includes: a motor generating a driving force according to a driving voltage; an oil pulse unit driven by the driving force and generating a torque in a pulse-like shape when the motor passes a strike position on a shaft thereof; and an output shaft on which a front end tool is mounted, the output shaft being connected to the shaft, characterized in that the oil pulse tool further comprises driving adjusting means to control the driving voltage, the driving voltage is reduced during a given period including a timing when the torque is transmitted to the output shaft, and the reduced driving voltage is increased when the given period is finished.

Abstract: A power tool includes a detecting member mounted in an output end of a housing, and a to-be-detected member mounted in a driver. When the driver is assembled with the output end of the housing, the detecting member will detect the to-be-detected member and transmit a signal to a torque adjustment unit disposed in the housing so as to enable the torque adjustment unit to automatically adjust the torque applied to the driver to reach a predetermined value, thereby preventing damage to the driver.

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: A circular saw in which cutting speed of a saw blade is smoothly controlled. A speed change mechanism of a circular saw includes first and second rotating shafts disposed parallel to each other, and first and second gear trains having different gear ratios and each having a combination of a drive gear and a driven gear as one unit which are engaged with each other and transmit torque of the first rotating shaft to the second rotating shaft. A torque transmission path via the first gear train is defined as a first power transmission path and a torque transmission path via the second gear train is defined as a second power transmission path, and the transmission path is switched between the first power transmission path and the second power transmission path.

Abstract: The present invention has disclosed a variable speed tool and a variable speed control method. The tool includes a switch; a gearbox housing; a motor; an outputting shaft; a multistage transmitting gear train and a gearshift ring which are mated with the motor and the outputting shaft, the gearshift ring having inner teeth; a gearshift fork mated with the gearshift ring; a tension spring arranged between the gearbox housing and the gearshift fork; and a torque sensing ring provided with a sliding groove in which the gearshift fork is movably disposed. When the load of the outputting shaft has reached to a predetermined value, the torque sensing ring makes the gearshift fork move axially in the sliding groove under the action of the tension spring, thus bringing the gearshift ring to move axially. The variable speed tool of the present invention may automatically adjust the rotating speed and the torque of the outputting shaft according to a variation of the load torque.