Abstract: A power tool enabled to detect an inadvertent rotation at higher accuracy includes a first sensor that detects a first driving information corresponding to a kinetic movement state of the tool body when the tool body is rotated around a longitudinal axis of the tool bit in the event of a working operation of the power tool, a second sensor that detects a second driving information corresponding to an output torque of the tool bit driven by the motor, and a controller connected to the first sensor and the second sensor for controlling the power tool. The controller is configured to calculate holding information corresponding to a holding force of a user to hold the tool body based on the first driving information and the second driving information and control the driving of the power tool based on the holding information.

Abstract: A safety apparatus for a portable tool having an internal combustion engine has at least one accelerometer providing a measurement of an acceleration of the portable tool in at least one plane or axis. An electronic controller is connected to an output of the accelerometer so as to receive analog or digital information. A generator is driven by the internal combustion engine so as to supply power to the accelerometer. A management card processes the analog or digital information so as to activate the system acting on an ignition exciter box so as to nearly instantaneously stop the internal combustion engine when the acceleration of the portable tool exceeds a predetermined level.

Abstract: A power tool device, in particular a hammer drill device and/or a chisel device, includes at least one torque limiting unit that is configured to limit a torque in a drivetrain in at least one operating state. The at least one torque limiting unit includes at least two force transmission mechanisms configured to transmit the torque in the at least one operating state. The at least two force transmission mechanisms have different transmission characteristics.

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 portable power tool having a housing with a rotation motor for powering a working implement, wherein sensors are provided to indicate the motor speed and the power supply, and a programmable evaluation unit is arranged to compare indicated speed and pressure values with stored limit values, and to accumulate the total operation time of the power tool and compare that with preset time limits for tool service intervals, and an optical information unit is provided on the housing to indicate whether those stored limit values have been reached.

Abstract: The invention relates to a power drill, having a tool-clamping device that is fastened to a spindle shaft, having a torque clutch that includes an axially movable clutch plate on which an axial force is exerted by a plurality of compression springs that cooperate at least indirectly with an adjusting nut situated on a housing component. The compression springs are accommodated in first recesses embodied in the longitudinal direction of the housing component. A device for axially moving an axial bearing situated on the spindle shaft, is provided at the end of the spindle shaft oriented toward the tool-clamping device. According to the invention, on its side oriented toward the clutch plate, the device for axially moving the axial bearing has at least one actuating section that is situated in a second recess of the housing component and on the side oriented toward the clutch plate, cooperates with an adjusting element for the device.

Abstract: A torsion-adjustable impact wrench, includes a housing, a powering unit including an impact mechanism configured to generate an intermittently increasing torque, an adjusting unit configured to manually set a first torsion value and generate a corresponding a first torsion signal, a detecting unit configured to detect a rotational speed of the powering unit and generate a corresponding first rotational speed signal, and a control unit configured to generate a control signal for controlling the output of the rotational speed of the powering unit. The control unit generates a second rotational speed signal according to the first torsion signal outputted by the adjusting unit, compares the first rotational speed signal with the second rotational speed signal, and generates a control signal enabling the rotational speed of the powering unit to approach the second rotational speed.

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: The invention relates to an assembly device (100) and method having a screw device (101) for tightening and loosening screws, having a screw head (102) and a housing (103), wherein measurement errors of an angle measuring device (104) are corrected by means of a detecting unit (105) for detecting erroneous sensor data in the rest state, and more precise and secure tightening of screws of nuts is thereby enabled.

Abstract: An improved method is provided for operating a power tool. The method includes receiving an input control variable from an input unit; determining a second derivative of the input control variable; selecting one of a plurality of control profiles based on the control input variable and the second derivative, 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: A rotary tool is provided with a mode selecting part that selects one operating mode from a predetermined plurality of operating modes when a mode switching button is pressed. The plurality of operating modes include: a first auto stop mode where a motor rotates only for a first time period after an impacting operation is detected; and a second auto stop mode where the motor rotates only for a second time period which is shorter than the first time period after the impacting operation is detected.

Abstract: A pneumatic torque impulse wrench comprises a housing (10), a motor (15), a hydraulic impulse unit (20) including an inertia drive member (21) and intermittently coupling the motor (15) to an output shaft (18), a shut-off valve (23) controlling the pressure air supply to the motor (15), and an activating mechanism (25) arranged to shift the shut-off valve (23) from a fully open position to a closed position via one or more partly closed positions. An activating mechanism (25) for shifting the shut-off valve (23) comprises a retardation responsive inertia element (28) movably supported on the inertia drive member (21), and a trip element (24) displaceable by the inertia element (28) and arranged to initially support the shut-off valve (23) in a fully open position during a screw joint tightening process and in succeeding one or more partly open positions for obtaining a power reduction of the motor (15) when approaching a target torque level.

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: An overspeed protection subsystem is provided for a power tool having an electric motor. The overspeed protection subsystem is comprised of: a motor switch coupled in series with the motor; a motor control module interfaced with the motor switch to control switching operation of the motor switch; and an overspeed detection module that determines rotational speed of the motor and disables the power tool when the rotational speed of the motor exceeds a threshold.

Abstract: According to a first aspect of the invention we provide an apparatus for reaction—free and reaction—assisted tightening and loosening of an industrial fastener including: a motor (102) to generate a turning force to turn the fastener; a turning force multiplication mechanism (210) for a lower speed/higher torque mode including a plurality of turning force multiplication transmitters (211, 212, 213); a turning force impaction mechanism (250) for a higher speed/lower torque mode including a plurality of turning force impaction transmitters (251, 252); a housing (220) operatively connected with at least one multiplication transmitter; a reaction mechanism (401) to transfer a reaction force generated on the housing during the lower speed/higher torque mode to a stationary object; wherein during the lower speed/higher torque mode at least two multiplication transmitters rotate relative to the other; and wherein during the higher speed/lower torque mode at least two multiplication transmitters are unitary to achiev

Abstract: An electric driver (1) as a power tool comprises a motor (2) which actuates a tool bit (100). The electric driver (1) has a first planetary gear mechanism (30), a second planetary gear mechanism (40), and a regulation member which regulate a second outer gear (43) to rotate. The regulation member includes an outer gear engaging member (50) and a deformable member (51) which is fixedly connected to the outer gear engaging member (50). The deformable member (51) extends in a direction in which a rotational axis of the first and the second planetary gear mechanism (30, 40) extends. A controller (61) is adapted to measure rotation torque based on displacement of the deformable member (51) via a strain gauge (55) which is attached on the deformable member (51).

Abstract: The invention relates to a method for decelerating a drive movement of a power tool and to a power tool suitable for carrying out the method, having a drive driven by a motor, an energy supply device for the provision of electrical energy, a controller having a motor controller for activating the motor and an operating-state recognition module which is to detect at least one operating-state variable and, as a function of this, to output a brake signal, the controller being designed to initiate, as a function of the brake signal, a braking procedure in which brake cycles are provided which have a first time segment, in which the motor is short-circuited, and a second time segment in which current is fed to the motor opposite to its original direction of rotation.

Abstract: There is provided a rotary impact tool that includes: a motor; a hammer configured to be rotated by the motor; an anvil configured to be intermittently applied with an impact force in a rotation direction by a rotational force of the hammer; a rotation speed detection device configured to detect a rotation speed of the motor; an extreme value pair detection device configured to detect an extreme value pair, which is a pair of a maximum value and a minimum value of the rotation speed, based on the rotation speed detected by the rotation speed detection device; and an impact detection device configured to detect that the impact force is being applied when an extreme value difference, which is a difference between the maximum value and the minimum value, is equal to or more than a first threshold value.

Abstract: The present invention includes a section (102) for generating a plurality of contributing random numbers using a random number, a section (110) for generating a plurality of contributing data using a plurality of contributing random numbers, a section (103) for selecting a number designating contributing data, a section (104) for generating a commitment of the number, a section (126) for saving a contributing random number of the number and disclosure information of the commitment, a section (125) for sending the plurality of contributing data and the commitment, section (134) for generating auxiliary data using a contributing data set and the contributing random number, wherein the auxiliary data and the disclosure information of the commitment are sent from the section (125), and a section (139) for generating a shared key using the contributing data set, the disclosure information of the commitment, the auxiliary data, and the contributing random number.

Abstract: The invention relates to a hand-guided electric tool having a motor and a pulse width modulator for generating a pulse width modulated signal for operating the motor. A unit is provided for reducing the EMC interferences emitted by the electric tool.

Abstract: A power tool for operating on a workpiece, the power tool having a housing and a motor disposed within the housing. A controller is connected to the motor and receives user inputs for turning on the motor and a power tool battery pack is connected to the controller and the motor. At least one light is connected to the controller for illuminating the workpiece. The controller can turn on the light in a predetermined pattern to alert the user to a tool condition, such as the charge level being below a predetermined level.

Abstract: An impact torque adjusting device is constructed by forming an operating fluid channel 11b communicating through the inside of a liner 7 which becomes a high-pressure chamber H and a low-pressure chamber L at the time impact torque is generated. In the operating fluid channel 11b, a valve disc 11d is urged in the direction opening the operating fluid channel 11b. Behind the valve disc 11d, an oil chamber 11e communicates with the inside of the liner 7 which becomes a high-pressure chamber H at the time impact torque is generated, so that the operating fluid channel 11b may be narrowed in proportion to the increase of the operating fluid.

Abstract: An improved method is provided for operating a power tool. The method includes: monitoring rotational motion of the power tool about an axis using a rotational motion sensor disposed in the power tool; determining a direction of the rotational motion about the axis; and driving the output member in a direction defined by the detected rotational motion of the tool, where the output member is driven by a motor residing in the power tool. Thus, the output member is drive clockwise when the rotational motion of the tool is clockwise about the axis and the output member is drive counter-clockwise when the rotational motion of the tool is counter-clockwise about the axis.

Abstract: An improved method is provided for operating a power tool. The method includes receiving an input control variable from an input unit; determining a derivative of the input control variable; selecting one of a plurality of control profiles based on the control input variable and the derivative, 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 electric power tool includes: a motor; an operation unit; a control parameter setting unit; and a control unit. The control parameter setting unit sets, as a control parameter of the motor, an optimum maximum rotational speed of the motor corresponding to a predetermined set torque or a control amount corresponding to the optimum maximum rotational speed. The control unit is configured to drive the motor in response to an operation amount of the operation unit and to control a rotational speed of the motor at or smaller than the optimum maximum rotational speed based upon the control parameter. The control parameter setting unit determines, as the optimum maximum rotational speed, a rotational speed of the motor that rotates with a rotational energy required to rotate the output shaft at the set torque and sets the optimum maximum rotational speed as the control parameter.

Abstract: An object of the present invention is to provide a threaded fastener tightening and loosening device capable of achieving operations of both tightening and loosening a threaded fastener at high speed and with high torque precision by means of a single rotation drive source. A first input shaft (5) which is rotated by being driven by an AC servo motor (3) is provided. A second input shaft (9) is connected to the first input shaft (5) via an electromagnetic clutch (8). An output shaft (11) to which a threaded fastener tightening tool is connected is provided. The second input shaft (9) is connected to the output shaft (11) while the first input shaft (5) is connected via a speed reduction device (12) and a tool clutch (14).

Abstract: A mechanical assembly for a power tool, and a power tool incorporating the mechanical assembly are provided. The mechanical assembly includes (i) a first member having a first axis and a first engagement portion inclined relative to the first axis, (ii) a second member having a second axis and a second engagement portion inclined relative to the second axis, wherein the first and second engagement portions engage each other by movement of the first and second members relative to each other in the direction of at least one of the axes; and wherein the first member is a ring gear and the second member is a central gear and the first and second engagement portions engage and disengage each other by movement of the second member within a space defined within the first member.

Abstract: A control scheme is provided for a power tool having a rotary shaft. The control scheme includes: monitoring rotational motion of the tool generally about a longitudinal axis of the shaft; detecting a condition of the tool based on the rotational motion of the tool; and controlling torque imparted to the shaft upon detecting the tool condition, where the torque is inversely related to an angular displacement of the tool about the longitudinal axis of the shaft.

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 improved method is provided for operating a power tool. The method includes receiving an input control variable from an input unit; determining a derivative of the input control variable; selecting one of a plurality of control profiles based on the control input variable and the derivative, 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: The invention is based on a hand-held power tool, in particular a cordless power tool, having a torque-limiting device that is provided for setting a maximum torque that a motor output is able to transmit to a tool-driving element. A spring mechanism equipped with at least one first disk spring is provided such that the at least one disk spring acts on at least two detent mechanisms arranged in a circumferential direction.

Abstract: An electric power tool includes an electric motor, a rotation speed detection device, a brake device, and a rotation speed-based activation device. The electric motor generates a driving force to rotate an object to be driven. The rotation speed detection device detects a rotation speed of the electric motor. The brake device executes braking control to brake the electric motor. The rotation speed-based activation device activates the brake device when the rotation speed detected by the rotation speed detection device becomes equal to or less than a specified rotation speed, which is arbitrarily set, after a stop command to shut off electric current supply to the electric motor is issued.

Abstract: The disclosure relates to a hand-held power tool including a housing having a handle portion, a tool portion for a tool that can be driven to move linearly and/or oscillate, an operator part on the housing side for the activation of the tool and/or the power tool on the user side, a drive unit for producing a working movement of the tool, an electronic unit for supplying the drive unit at least with open-loop control and/or closed-loop control signals, and an operating voltage unit for making an electrical DC voltage available. The drive unit includes at least one excitation actuator, especially an ultrasonic actuator, having a volume of an excitation-active material. The actuator is supplied with power by the operating voltage unit, when operated, and is controlled in an open or closed loop control by the electronic unit.

Abstract: A transmission assembly is powered by an electric motor and includes a transmission having an outer ring gear, a connector moveable relative to the outer ring gear between a first position, in which the connector is rotatable with the transmission in response to torque received from the motor, and a second position, in which the connector and the outer ring gear are non-rotatable, and a control mechanism operable to detect the operating current of the motor and compare the operating current to a threshold current. The control mechanism is operable to move the connector from the first position to the second position in response to the motor operating current exceeding the threshold current.

Abstract: A power tool includes an output shaft configured to rotate about a longitudinal axis, a motor drivably connected to the output shaft to impart rotary motions thereto, and a rotational motion sensor spatially separated from the output shaft and operable to determine the user-imparted rotational motion of the power tool with respect to the longitudinal axis. A controller is electrically connected to the rotational motion sensor and the motor. The controller determines angular velocity of the power tool about the axis, rotational displacement of the power tool about the axis, and/or a direction of the rotational displacement using input from the rotational motion sensor. The controller then controls the motor according to the angular velocity, the rotational displacement, and/or the direction of the rotational displacement.

Abstract: A hammering tool includes, within its tool main body, a piston which reciprocates by using a motor as its drive force, a hammering member which carries out its hammering operation in linking with the reciprocating motion of the piston, and an intermediate member which transmits a hammering force of the hammering member to a top end tool mounted on the top end of the tool main body. The tool main body further includes a measuring device which measures a hammering state of the hammering member and a control device which controls the number of rotations of the motor. The control device, according to measurement results of the measuring device, determines the limit number of times of hammering where the hammering member becomes unable to follow the reciprocating motion of the piston, and thus controls the number of rotations of the motor.

Abstract: A clutch arrangement that includes a clutch member and a follower member. The clutch member is coupled to a member of the transmission assembly that is proximate the torsional input of the transmission assembly and which must be in a non-rotating position to permit the transmission assembly to perform a torque multiplication operation. The follower member is biased into engagement with the clutch member to inhibit relative rotation therebetween. As the clutch member and the transmission member are coupled to one another, the transmission assembly is able to perform a torque multiplication operation. When, however, the torsion that is exerted onto the clutch member is sufficient to overcome the frictional engagement between the follower and clutch members, the clutch member, and the transmission member, rotate, thereby inhibiting the capability of the transmission to continue to perform the torque multiplication operation.

Abstract: A power tool having a gear speed reducing mechanism which is free of backlash and a planetary gear speed reducing mechanism. The planetary gear speed reducing mechanism has a driving-side member that is rotationally driven by a prime mover, a driven-side member which is rotatably and coaxially disposed with the driving-side member and to which a tool bit is coupled, and an intervening member which is disposed between the driving-side member and the driven-side member. The intervening member is configured as a planetary member and at least caused to rotate by frictional force acting on its contact surface in contact with the driving-side member when the driving-side member is rotationally driven, so that torque of the driving-side member is transmitted to the driven-side member at reduced speed.

Abstract: A power tool with a handle housing, a motor, an output member and a cassette. The handle housing that defines a handle. The motor is received in the handle housing. The cassette is received in the handle housing and includes a transmission housing, a multi-stage transmission received in the transmission housing, and a rear thrust washer. The transmission housing has a first end with first and second circumferentially extending channels formed therein. The rear thrust washer has a body and first and second lock members that extend radially from the body. Each of the first and second lock members is received in an associated one of the first and second circumferentially extending channels.

Abstract: Apparatus for determining when a fastener has been tightened by an impact wrench comprises determining when the number of hammer impacts to advance an anvil of the impact wrench through a predetermined angle reaches a predetermined number. The cumulative angular displacement of the anvil from the first detected hammer impact is determined from the corresponding cumulative angular displacement of the hammer at the corresponding hammer impact from the first detected hammer impact. The cumulative angular displacement of the hammer is determined just prior to the direction of rotation of the hammer reversing at the corresponding hammer impact, and is determined by computing the difference between the cumulative angular displacements of the hammer at the corresponding and previous hammer impacts and subtracting an angle through which the hammer freely rotates between the two hammer impacts from the computed difference.

Abstract: It is an object of the invention to provide a technique that contributes to further improvement of an impact tool. A representative impact tool includes a motor, a tool body that houses the motor, a dynamic vibration reducer and a driving mechanism part that is driven by the motor and forcibly drives the dynamic vibration reducer by applying an external force other than vibration of the tool body to the dynamic vibration reducer, during hammering operation. At least one of the dynamic vibration reducer and the driving mechanism part is mounted to the tool body in a form of an assembly into which at least one of a plurality of component parts forming the dynamic vibration reducer and a plurality of component parts forming the driving mechanism part are assembled in advance.

Abstract: A portable device having an overload protection device for motor-operated tools has a drive motor, a drive shaft connected to the drive motor and driven in rotation by the drive motor, and an output shaft for driving a cutting tool, wherein the output shaft is arranged substantially perpendicularly to the drive shaft. A drive pinion is connected to the drive shaft. A drum is supported on the output shaft and driven in rotation by the drive pinion. A coupling is arranged between the drum and the output shaft and engages the drum. The coupling is connected to the output shaft. When the output shaft is blocked, the coupling effects an automatic decoupling between the drum and the output shaft in order to prevent overloading of the drive motor.

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: In suppressing chatter vibration of a rotary shaft in a machine tool by fluctuating rotation speed of the rotary shaft, easy setting of a fluctuation parameter is realized. In a monitor apparatus of the machine tool, a graph showing a fluctuation amplitude of the rotation speed is displayed. On this graph, a current fluctuation position (first point) is indicated by a black circle marker, and also, a power limit line L of a motor fluctuation period is depicted based on a predetermined equation. In an area not exceeding the power limit line L, a new fluctuation position (second point) having a larger fluctuation amplitude and a shorter fluctuation period than the current fluctuation position is calculated and indicated with an arrow A guiding this new point from the current fluctuation position.

Abstract: The invention is based on a method for producing a screw connection by means of a cutout screwdriver (10) that terminates a screw driving operation when a predetermined torque is achieved. According to the invention, data relating to an operation are detected in the cutout screwdriver (10) and transmitted to an external monitoring unit (20). The invention also discloses a device for executing the method as well as a cutout screwdriver.

Abstract: A device has a torque-limiting unit of a power drill, wherein torque-limiting unit is intended to limit a screwdriving moment in a screwdriving function; and a power drill is provided with the new torque-limiting unit.

Abstract: An impact rotary tool is provided that is switchable between an impact mode where the tool delivers an impacting torque on an output tool and a drill mode where the driver delivers a smooth output on an output tool. The impact rotary tool includes an impact mechanism and a hammer block that in the impact mode is movable parallel to the axis of the driver shaft and delivers reciprocating blows to rotate an anvil and in the drill mode substantially constantly engages the anvil. The impact mechanism includes a stopper that does not contact the hammer block in the impact mode and engages the hammer block in the drill mode to maintain the substantially constant contact between the hammer block and the anvil.

Abstract: The invention relates to a hand tool machine with a torque limiter (2) enabling a user to set a maximum torque which is transmitted by a motor drive (4) to a tool carrier (6). According to the invention, the hand tool machine comprises an overload clutch which interrupts a power flux between the motor drive (4) and the tool carrier (6) when the transmitted torque exceeds the overload torque.

Abstract: An electric power tool includes a motor; a speed reducer for transferring a rotational power of the motor at a reduced speed; and a reduction ratio changing unit for changing a reduction ratio of the speed reducer. The speed reduction mechanism includes an axially slidable changeover member and a gear member, the changeover member being engaged with or disengaged from the gear member depending on an axial slide position thereof. The reduction ratio changing unit includes a shift actuator for axially sliding the changeover member, a driving state detector for detecting a driving state of the motor, a slide position detector for detecting a slide position of the changeover member and a controller for driving the shift actuator and for changing a drive control of the shift actuator depending on detection results of the slide position detector unit and the driving state detector unit, respectively.

Abstract: A control system is provided for use in a power tool. The control system includes: a rotational rate sensor having a resonating mass and a controller electrically connected to the rotational rate sensor. The rotational rate sensor detects lateral displacement of the resonating mass and generates a signal indicative of the detected lateral displacement, such that the lateral displacement is directly proportional to a rotational speed at which the power tool rotates about an axis of the rotary shaft. Based on the generated signal, the controller initiates a protective operation to avoid further undesirable rotation of the power tool. The controller may opt to reduce the torque applied to shaft to a non-zero value that enables the operator to regain control of the tool.