Abstract: The present invention provides a rotational force transmitting device including: an inertia wheel 100 connected to an output gear 22 rotating engagedly with a driving motor 11 and rotating by receiving the rotational force of the driving motor 11; a spindle 200 coupled freely rotatable to the center of the front surface of the inertia wheel 100; a power transmitting eccentric body 210 extended vertically with respect to the rotary shaft of the spindle 200 from one side of the spindle 20; an insert pin 300 inserted into a guide hole 110 formed passed through the front and rear surfaces of the inertia wheel 100; a position restoring spring 320 inserted into the guide hole 110, for elastically supporting the insert pin 300 in a backward direction; and a balance weight 400 coupled rotatably to the rear surface of the inertia wheel 100, for supporting the rear end periphery of the insert pin 300, the balance weight 400 rotating with the centrifugal force generated by the rotation of the inertia wheel 100 to push t

Abstract: A power tool that includes a driving motor and a power transmitting mechanism. The power transmitting mechanism includes a first clutch cam part, a second clutch cam part, clutch teeth, a clutch detecting mechanism and a controller that can control the driving motor in a first control mode in which the driving motor is controlled to rotate at a first rotation speed until before the first and second clutch cam parts are engaged with each other at the clutch teeth and in a second control mode in which the driving motor is controlled to rotate at a second rotation speed higher than the first rotation speed after the first and second clutch cam parts are engaged with each other at the clutch teeth.

Abstract: A driving section generates rotational driving force and has an output shaft that outputs the rotational driving force. An end-bit mounting section holds an end bit and is rotatable about a rotational axis. A friction clutch is provided between the end-bit mounting section and the driving section. The friction clutch includes a drive member and a follow member. The drive member rotates together with the driving section and has a drive-side contact surface. The follow member rotates together with the end-bit mounting section and has a follow-side contact surface contactable with the drive-side contact surface. The friction clutch is movable between a transmission position where frictional force is produced between the drive-side contact surface and the follow-side contact surface so that the output shaft and the end-bit mounting section can rotate together, and a cutoff position where the output shaft and the end-bit mounting section are non-rotatable together.

Abstract: In a clutch mechanism of a percussion driver drill, a plurality of engageable members held in a gear case is configured to be engageable with an end face of a final-stage internal gear, and a coil spring is configured to press the engageable members against the end face of the internal gear. The coil spring is disposed frontwardly of the engageable members between a switch member and an operating member of a vibration mechanism. A coupling member connected with the switch member and the operating member is disposed to pass through a gap between the plurality of engageable members and detour around a rear end of the coil spring.

Abstract: The invention relates to a hand-held power tool with a drive shaft embodied in the form of a spindle shaft, which is connected to a tool-clamping device. The drive shaft, which is coupled to a drive motor, cooperates with a torque clutch. The torque clutch is provided with a clutch-adjusting ring that is coupled to a transmission element that cooperates with at least one clutch-adjusting device in order to adjust a torque. The transmission element is situated in an axially and/or radially movable fashion on the outer circumference of a housing component. According to the invention, in at least one position of the clutch-adjusting ring, the transmission element protrudes axially beyond the housing component in the direction toward the tool-clamping device.

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: The invention describes a hand-held power tool having a drive train, which includes a motor with a rotor, a drive shaft, and a transmission. According to the invention, at least one flywheel mass is provided that is positionable rotationally symmetrical to the drive shaft and connectable to the drive shaft for co-rotation therewith.

Abstract: A power tool includes a housing, a motor supported in the housing, a transmission operably coupled to the motor, an output shaft rotatable about a central axis, a clutch mechanism including a resilient member, and a clutch mechanism adjustment assembly having a first ring rotatable about the central axis. The first ring includes a cam surface spaced from the central axis in a radial direction. The clutch mechanism adjustment assembly also includes a second ring coaxial with the first cam ring and in facing relationship with the cam surface, and a cam member disposed between the cam surface and the second ring. In response to rotation of the first ring relative to the second ring, the cam member engages the cam surface to displace the first ring relative to the second ring and compress the resilient member to increase the amount of torque transferred to the output shaft.

Abstract: An electric power tool includes a motor having a drive shaft, a tool output shaft rotated by rotational force of the drive shaft, a clutch unit that connects or disconnects a torque transmission line between the drive shaft and the tool output shaft according to load torque of the tool output shaft, a load detector that outputs a load torque signal in accordance with the load torque of the tool output shaft, and a control unit that performs a rising detection mode, which detects rising of the load torque signal to stop rotation of the motor, and a falling detection mode, which detects falling of the load torque signal to stop rotation of the motor. The control unit selects the rising detection mode or the falling detection mode according to a usage condition signal indicating a usage condition of the electric power tool.

Abstract: A control method for a power tool and a power tool is disclosed. The control method has an operating mode and a safety mode. In the operating mode, a motor drives a tool receptacle in a rotating manner. In the operating mode, the motor has a power consumption in the amount of at least an operating value. The safety mode is triggered if a sensor device detects a rotational blockade of the tool receptacle. In the safety mode, a clutch that is switchable by electrical signals located in the drive train between the motor and tool receptacle is periodically opened and closed and a power consumption of the motor is reduced as compared to the operating value.

Abstract: Embodiments of clutches for electric pole saws, and related methods, are disclosed herein. An electric pole saw may include an electric motor, a drive shaft coupled between the electric motor and a cutting instrument, and a clutch coupled between the electric motor and the drive shaft. The clutch may include a motor portion having an exterior surface, a drive shaft portion having an exterior surface and forming a mated assembly when mated with the motor portion, and a spring around the motor and drive shaft portions. The spring may exert a holding force on the mated assembly, such that rotation of the motor portion in a first direction loosens the spring and reduces the friction holding force until a torque between the motor and drive shaft portions exceeds the holding force, causing rotation of the motor portion to be decoupled from rotation of the drive shaft portion.

Abstract: The invention relates to a power tool, in particular an electrically operable hand-held power tool, having at least one tool drive shaft for direct or indirect rotary drive of an insert bit, with the insert bit being accommodated in a tool holder that is connected or detachably connected to the tool drive shaft, particularly in a replaceable fashion. At least one drive device and at least one clutch device that couples the at least one drive device to the at least one tool drive shaft is provided which has at least two different, user-selectable, limit torques. An actuating device is provided that makes it possible, with a replacement of the insert bit and/or a replacement of the tool holder, to reset the clutch device to a lower limit torque, preferably to the lowest possible limit torque.

Abstract: The invention relates to a multi-gear transmission device, particularly a two-gear transmission device, for transferring a drive torque from an input side to an output side, which transmission device has at least two selectable gear ratios. The multi-gear transmission device further has a multi-stage clutch device, particularly a two-stage clutch device, with at least two different, selectable limit torques. According to the invention, the multi-stage transmission device has at least two preferably switchable translating gear pairs, and the multi-stage clutch device is included in the translating gear pairs.

Abstract: In a hand-held power tool having a transmission and a torque clutch, which has a torque limiting coupling associated with the transmission and with which a limiting transfer element is associated, to which at least one spring element is axially applied in the direction of the torque limiting coupling, a torque level of the torque clutch being settable via a user-operable operating element at least within predefined limits, the torque limiting coupling has at least one roller-shaped latch member.

Abstract: The invention relates to a power drill, having a tool-clamping device that is coupled to a drive motor via a drive shaft and a torque clutch equipped with a transmission element. The torque clutch has a clutch-adjusting ring that cooperates at least indirectly with at least one clamping element that exerts a prestressing force on the transmission element. An end of the drive shaft oriented toward the tool-clamping device is guided in a bearing that axially fixes the drive shaft in a drilling or screwdriving position and axially releases the drive shaft in an impact drilling position. The bearing cooperates with a bearing holder, which moves the bearing axially via a user-actuatable actuating element. According to the invention, the actuating element is coupled to an adjusting element that axially fixes the transmission element and axially releases the bearing in the impact drilling position and axially releases the transmission element and axially fixes the bearing in the drilling or screwdriving position.

Abstract: A synchronization mechanism of a clutch mechanism includes a drive side contact member and a driven side contact member provided on a drive side clutch member and a driven side clutch member of a clutch mechanism at positions radially inwardly of a drive side clutch portion and a driven side clutch portion, respectively. The driven side contact member does not contact the drive side contact member when the driven side clutch member is in a disengaging position. As the driven side clutch member moves from the disengaging position to an engaging position, the driven side contact member contacts the drive side contact member, so that the rotation of the drive side clutch member is transmitted to the driven side clutch member through frictional contact between the driven side contact member and the drive side contact member before the driven side clutch member reaches the engaging position.

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 temporarily decreasing or increasing a rotational power of the motor depending on detection results of the driving state detector and the slide position detector, respectively.

Abstract: A technique is provided which improves durability in a power tool having a torque transmission device. The representative power tool has a torque transmission device 151. The torque transmission device 151 includes a projection 171 formed on one of opposed surfaces of a first rotating member 153 and a second rotating member 155 and protruding in a direction of a rotational axis, a recess 161 for receiving the projection 171, which is formed in the other of the opposed surfaces and recessed in the direction of the rotational axis, a projection-side engagement surface 175a formed on the projection 171, and a recess-side engagement surface 165a formed on the recess 171. Torque is transmitted when the projection-side and recess-side engagement surfaces 175a, 165a are engaged with each other, while the torque transmission is interrupted when the projection-side and recess-side engagement surfaces 175a, 165a are disengaged from each other.

Abstract: A power tool that includes a housing, a motor, a pair of motor bearings, a transmission, an output spindle and front and rear spindle bearings. The motor is received in the housing and includes a stator and an output shaft that extends through the stator. The motor bearings support the output shaft for rotation relative to the housing and are disposed on opposite ends of the stator. The transmission is driven by the motor and includes an input pinion that is mounted to the output shaft for rotation therewith. The output spindle is driven by the transmission. The front spindle bearing is mounted to a front end of the output shaft radially between the housing and the output shaft. The rear spindle bearing is mounted to a rear end of the output spindle and a portion of the rear spindle bearing rotates with the output shaft.

Abstract: The universal control module is designed for controlling the operation of a plurality of motors and/or configured for a plurality of different motor applications. In an example, the control module is configurable within a housing of a power tool. The control module includes a top cover, a bottom cover and a printed circuit board (PCB) with control components thereon. The control module includes a spacer configured between the top and bottom covers and attached to the PCB for providing tolerances for the control components during a soldering process to fixedly attach the control components to the PCB.

Abstract: A transmission assembly for a power tool includes a first transmission path comprising a high speed transmission path, a second transmission path comprising a low speed transmission path, a controller for one of engaging and disengaging the high speed transmission path, and a clutch for enabling the low speed transmission path to operate at a lower speed than an output of the transmission assembly when the high speed transmission path is engaged.

Abstract: A tool holder for use with a power tool includes an input shaft with a rear portion couplable to a power tool, and an output shaft with a front portion couplable to a tool bit. A clutch assembly releasably non-rotationally couples a front portion of the input shaft to a rear portion of the output shaft, and includes a recess in the front portion of the input shaft or the rear portion of the output shaft, an aperture in the other of the front portion of the input shaft or the rear portion of the output shaft, a roller received in the aperture, and a spring that biases the roller radially inwardly toward the recess. The spring enables release of the roller radially outwardly from the recess when a predetermined torque threshold is exceeded, such that torque is not transmitted from the input shaft to the output shaft.

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: A power tool having an electric motor with a static stall torque and a housing, a tool holder being mounted on the housing rotatably about an axis of rotation, the electric motor being connected to the tool holder, a handle for an operator being provided on the housing, the handle having a handle length, characterized in that the ratio of the static stall torque to the handle length is greater than 400 Nm/m.

Abstract: An electrical power tool may include an electric motor, a speed change device, and a battery pack. The speed change device is capable of changing a reduction ratio thereof and capable of automatically switching between a high speed low torque mode in which a high speed low torque is output and a low speed high torque mode in which a low speed high torque is output, based on an external torque applied to a spindle. A distance from the axis to a center of gravity of the battery pack and a mass of the battery pack are set such that an inertia moment around the axis is greater than a reaction around the axis that is produced when the high speed low torque mode is changed to the low speed high torque mode in the speed change device.

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 power tool with a motor, a housing, a transmission, an output spindle, a front bearing and a rear bearing. The motor has an output shaft. The transmission is disposed in the housing and receives a rotary input from the output shaft. The transmission includes an input planetary stage, which has an input planet carrier, and an output planetary stage. The output spindle is driven by the transmission and has a first end, which extends at least partly through the input planetary stage, and a second end opposite the first end. The front bearing is disposed between the output spindle and the housing to support the second end of the output spindle for rotation about the spindle axis. The rear bearing indirectly supports the first end of the output spindle in the housing for rotation about the spindle axis.

Abstract: A hand-held power tool has a tool housing in which a gear unit which is drivable by a drive motor for driving a drive shaft is situated and to which a torque clutch is assigned. On the hand-held power tool, the drive shaft is provided with a tool holder for holding an assigned insertion tool, and an acceleration sensor is provided which is designed for enabling detection of an activation of the torque clutch.

Abstract: The screwdriving power tool includes a hollow spindle (8) rotatably supported in the tool housing (4) and driven by a motor (26), a clutch (30) that rotatably connects and disconnects the hollow spindle (8) with and from the motor (26), respectively, in engagement and disengagement positions of the clutch (30), a screwing-in spindle (6) connected with a chuck (10) for a working tool (12) and connected with the hollow spindle (8) for a joint rotation therewith and for an axial displacement relative thereto, and a percussion mechanism (14) for applying a pulsed axial force to the screwing-in spindle (6), with the clutch (30) being brought into its engagement position by the screwing-in spindle (6) by being displaced against a biasing force of the clutch springs (40, 44), and being locked in its engagement position.

Abstract: In a speed change device of an electrical power tool, a reset arm is provided separately from a switch lever, which arm is operated by a reset motor. Due to tilting motion of the reset arm, a lock ring can be returned to an unlocking position in which a second stage internal gear can be rotated, so that the speed change device can be rest to a high speed low torque mode.

Abstract: A surgical cutting and fastening instrument. The instrument comprises an end effector and a shaft connected to the end effector. The shaft comprises a drive train for powering the end effector. The instrument also comprises an electric, DC motor connected to the drive train for powering the drive train. The instrument also comprises a torque-limiting device connected between to an output pole of the motor and an input pole of the drive train.

Abstract: A power tool includes a housing, a motor disposed in the housing, a transmission disposed in the housing and coupled to the motor, an output end effector coupled to the transmission, a control circuit for controlling power delivery from a power source to the motor, and a force sensing electronic clutch including a force sensor coupled to a substantially stationary element of the transmission. The force sensor senses a reaction torque transmitted from the end effector to at least a portion of the transmission. The sensor is configured to generate a first electronic signal corresponding to an amount of the reaction torque. The control circuit compares the first electronic signal with a second electronic signal corresponding to a desired threshold torque value, and initiates a protective operation when a value of the first electronic signal indicates that the reaction torque has exceeded the desired threshold torque value.

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: 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: A pneumatic power tool includes a pneumatic motor mounted in a housing and supplied to pressured air through an air control unit to rotate a drive coupler, a coupling shell member surrounding the drive coupler and having axially opposite actuating and engaging regions, an output spindle having a bearing surface disposed between the drive coupler and the engaging region, and an override clutch unit coupling the drive coupler to the coupling shell member. An override movement of a driven clutch half on the engaging region brings the actuating region to move axially so as to force a latch to an unlatched position such that the air control unit is displaced to a shut-off state.

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: 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: A torque system of a power tool includes a combination of a first body and a second body, in which a toothed ring is assembled; and a mode selecting assembly, a torque adjusting module and control pins disposed on the second body. The torque system further includes restricting mechanisms formed on the second body, and the control pins are respectively disposed in the restricting mechanisms. One side of the control pin has a stopper block, and the restricting mechanism includes a first stopper, a second stopper and a through hole. When the control pin is driven to rotate and the stopper block faces the first stopper or the through hole, the object of switching each operation mode is achieved.

Abstract: In a clutch mechanism of a percussion driver drill, a plurality of engageable members held in a gear case is configured to be engageable with an end face of a final-stage internal gear, and a coil spring is configured to press the engageable members against the end face of the internal gear. The coil spring is disposed frontwardly of the engageable members between a switch member and an operating member of a vibration mechanism. A coupling member connected with the switch member and the operating member is disposed to pass through a gap between the plurality of engageable members and detour around a rear end of the coil spring.

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: In a power tool, a planetary gear speed reduction mechanism is provided in a gear case, and a spindle is configured to receive a torque of a motor transmitted through the planetary gear speed reduction mechanism. A final-stage internal gear is rotatably provided at a final stage of the planetary gear speed reduction mechanism. A clutch mechanism includes a coil spring configured to press the final-stage internal gear from a front side. The clutch mechanism is configured to cause the internal gear to run idle, thereby interrupting transmission of torque, at overload beyond a pressing force of the coil spring. An elastic member is interposed between an inner peripheral surface of the gear case and an outer peripheral surface of the final-stage internal gear, to give resistance to the final-stage internal gear at idle.

Abstract: A transmission assembly for a power tool includes a first transmission path comprising a high speed transmission path, a second transmission path comprising a low speed transmission path, a controller for one of engaging and disengaging the high speed transmission path, and a clutch for enabling the low speed transmission path to operate at a lower speed than an output of the transmission assembly when the high speed transmission path is engaged.

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 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: 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 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 screw driver capable of avoiding co-rotation of an end bit and a motor in case of sharp shooting the end bit with a groove in a head of a screw. A co-rotation preventing mechanism is engageable with an end bit mounting portion when the end bit mounting portion is at a frontward position to prevent the end bit mounting portion from being rotated in the forward direction and to allow the end bit mounting portion to rotate in the reverse direction. The preventing mechanism is disengageable from the end bit mounting portion when the end bit mounting portion is at the rearward position to allow the end bit mounting portion to rotate in both forward and reverse directions.

Abstract: The invention related to a multi-functional power tool, comprises an housing, a motor set in the housing, a main shaft driven through the rotation of the motor, a working shaft extended outside the housing, an active impact block, which can rotate with and make axial motion with respect to the main shaft, is configured on the main shaft, a passive impact block which rotates with the working shaft and can alternatively make axial motion with respect to the working shaft is mounted on the working shaft, the active impact block rotates to drive the passive impact block through the coordination of the first end tooth set on the active impact block and the second end tooth set on the passive impact block; the power tool further includes a function shifting button which can move between the first location and the second location to alternatively limit the passive impact block's axial motion with respect to the working shaft, in this way to realize the shifting between the first function and the second function of t

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.