Abstract: A multi-speed drill includes a housing with a motor including an output member. A constant mesh parallel axis transmission can be disposed in the housing and can include a high speed and low speed gears. A clutch member can be associated with the low speed gear. A conical spring can bias the low speed gear and the clutch member together for torque transfer up to a predetermined torque level. Above the predetermined level, cam surfaces between the low speed gear and the clutch member move them apart, thereby limiting torque transfer to the output spindle. In the high speed mode the torque transfer between the input pinion and the output spindle bypasses the clutch member. The maximum torque level capable of being generated at the output spindle in the high speed mode can be less than the predetermined torque level.

Abstract: Problems: For enhanced safety of a work apparatus with an internal combustion engine, a cutting element is prevented from an accidental run due to an accidental increase of the engine revolution while a throttle control trigger is in a released state. Solution: In an engine start period, a throttle valve (10) is in a first idling position. The engine 2 at its initial run phase does not increase in revolution because of instability of its running condition. When the running condition begins to stabilize, the revolution rapidly increases. When the engine revolution (Ne) reaches 4,000 rpm or higher, a non-firing control mode is set up. In the non-firing control mode, when the engine revolution reaches or exceeds 4,500 rpm, a non-firing processing is executed (S4). A centrifugal clutch (6) is designed to engage at 5,000 rpm.

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

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

Abstract: A method and software product for controlling a percussion device belonging to a rock-drilling machine, and a percussion device. The impact frequency of the percussion device is set so that the percussion device forms a new compression stress wave to the tool always when reflected waves from the previous compression stress waves reach a first end of the tool. This requires that the impact frequency be set proportional to the propagation time of the stress wave, whereby the length of the used tool and the propagation velocity of the stress wave in the tool material are to be noted.

Abstract: The invention relates to a power screwdriver (10) comprising a motor (12) as the drive, a desired torque default element (52) and an actual torque determination element (46), a torque gradient determination element (48) and a motor control (40) which controls the motor (12) depending on the torque gradient (dmd_lst/dt). The invention is characterized by a torque threshold determination element (50) which provides a torque threshold value (Md_Lim, Md_Lim1, Md_Lim2) that depends on the torque gradient (dmd_lst/dt) and lies below the desired torque value (Md_Soll). If the actual torque value (md_Ist) exceeds the torque threshold value (Md_Lim, Md_Lim1, Md_Lim2), a motor control (40) presets a speed reduction for the motor (12) or already completely switches off the motor (12). The power screwdriver (10) according to the invention avoids torque overshoots and yet allows the desired torque value (Md_Soll) to be exactly reached in the shortest time possible.

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

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

Abstract: The invention relates to a power screwdriver (10) comprising a motor (12) and a control circuit (22) which switches the motor (12) off by means of a switch-off signal (s_Stop) when it reaches a preset desired torque value (Md_Soll), and a supporting arm (18) which absorbs energy during screwing. The invention is characterized by a voltage limiting circuit (46) that limits the motor voltage (u_Mot) occurring on the motor (12) when the energy stored in the supporting arm (18) of the motor (12), which is driven as the generator and rotates counter to the direction of drive, is dissipated, to a predetermined limiting voltage (u_Lim). The limiting voltage (u_Lim) is fixed in such a manner that the motor (12) is capable of rotating without counter-torque counter to the direction of drive when operated in the generator mode and that yet no inadmissible overvoltages occur.

Abstract: A power tool includes a driving unit for performing screw tightening operations; a motor for rotatably driving the driving unit; a trigger switch for turning on and off the motor; and a control circuit, accommodated in a main body of the power tool, for monitoring the screw tightening operations. The control circuit having a screw tightening completion detection unit for detecting completion of a screw tightening operation, a screw tightening count unit for counting the number of detected tightening operations, a screw tightening number setting unit for presetting the number of screws to be tightened, a screw tightening completion notifying unit for notifying completion of the screw tightening operations when the number of detected tightening operations reaches the preset number of screws.

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

Abstract: A system and method for determining the actual torque being applied by an impact tool to a shaft of a fastener is disclosed, wherein an equation having a set of parameters that represent the time-amplitude curve of the individual pulses produced by the impact tool are used to correlate the impact tool pulses and the residual torque in the fastener without requiring knowledge of the torque of the fastener joint.

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: A hammer drill includes a motor; a spindle rotatingly driven by the motor and holding an output bit; a motion conversion member for converting rotational movement of the motor to reciprocating movement; a striker reciprocatingly driven by the motion conversion member for applying an axial striking force to the output bit; a striking-motion-releasing mechanism for releasing the striking force applying action exercised by the striker; and a tightening-torque adjusting clutch for interrupting the transfer of the rotational force to the output bit by increasing a load torque.

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.

Abstract: The invention relates to a method for operating a handheld electric power tool, having an electric motor that is drivable at a rated torque as the maximum allowable motor torque by the application of a maximum allowable motor current. The method includes the steps of manually furnishing a specification of a maximum torque, in which the maximum torque is within a setting range between a minimum set torque and the rated torque, operating the electric motor by applying a motor voltage which corresponds to an rpm desired by the user, and limiting the motor current to a current value that depends on the furnished specification of the maximum torque. The invention also related to a drive unit for an electric power tool, which includes an electric motor drivable at a rated torque as a maximum allowable motor torque by application of a maximum allowable motor current. A setting element manually furnishes a specification of a maximum torque, the maximum torque being within a range between zero and the rated torque.

Abstract: A power tool including a drive assembly including a first clutch assembly having an engaged configuration, in which the first clutch assembly transfers a drive force from a motor shaft to a spindle, and a disengaged configuration, in which the first clutch assembly prevents the transfer of the drive force. The first clutch assembly can be movable toward the disengaged configuration when a torque exerted on the spindle exceeds a torque limit. The drive assembly can also include a second clutch assembly having an engaged configuration, in which the second clutch assembly transmits the drive force from the motor shaft to the spindle, and a disengaged configuration, in which the second clutch assembly prevents the transmission of the drive force. The second clutch assembly can be movable toward the engaged configuration when the tool element engages a workpiece.

Abstract: Conventionally, as screw tightening axial force control, there is a control method such as a torque control method. The torque control method requires estimation of a torque coefficient, and has a problem that a calculated axial force value is an estimated value. An object of the present invention is to provide a method for directly controlling an axial force by calculating the axial force generated by an impact force by using an impact wrench. A 45-degree slant line is set from an origin O of orthogonal coordinate axes to be used for screw tightening axial force control, an impact progress point Hi generated by an i-th impact is detected on the 45-degree slant line, a length HSi of a line segment OHi is read, and an axial force value Fi after the i-th impact occurs is calculated by using the formula Fi=HSi×cos 45°. Another method for controlling the axial force by using impact information is also disclosed.

Abstract: To provide a rotary tool driven by a brushless motor with which constant torque tightening work for screws or the like can always be performed properly and efficiently, in which overall downsizing and improved torque control precision enhancement can easily be achieved, and with which it is possible to eliminate occurrences of switch contact-induced sparking and wear and of the damage imparted to the peripheral electronic equipment and electronic circuitry as occurred in drive switches or torque detection mechanisms that use a conventional mechanical switch mechanism, so that the constituting parts are able to have a reduced size and an extended life.

Abstract: A method and an apparatus for controlling the rate of pressure applied to an air controlled device. The apparatus includes a flow restrictor, a regulator, and a dome loaded regulator. The regulator is configured to be operatively connected to a pressure source and is set to a first selected pressure. The flow restrictor is arranged to control the rate of applying pressure to the air controlled device after the first pressure is reached. The dome loaded regulator is in communication with the regulator and the flow restrictor such that the regulator and the flow restrictor alternately determine the flow rate from the pressure source to the air controlled device. The method includes setting a predetermined parameter and automatically reducing the rate of applying pressure to the air controlled device after the predetermined parameter is reached.

Abstract: An electric impact tool in which a rotating mass rotates in a forward direction to impact upon and transfer torque to an anvil, and rotates in a reverse direction opposite the forward direction in response to such impact. A direction sensor monitors the direction of rotation of the rotating mass, and a controller turns an electric motor on and off during respective forward and reverse rotation of the rotating mass. An energy storing mechanism may be used to absorb energy from reverse rotation of the rotating mass and release the absorbed energy to rotate the rotating mass in the forward direction. A controller may be used to store the angular position of the rotating mass upon each impact and turn off the motor prior to the following impact to avoid energizing the motor during stall.

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

Abstract: It is an object of the invention to provide an effective technique for improving the durability of a torque limiter utilized in a power tool. The object is achieved by a representative power tool comprising a tool bit, a driving mechanism and a torque limiter. The torque limiter includes first and second rotating members, a ball, a pressing member and an elastic member. The second rotating member includes a power transmitting region with a groove continuously formed from a deepest groove part to a shallowest groove part to allow torque transmission and a power transmission interrupted region with a groove shallower than the shallowest groove part of the power transmitting region to interrupts the torque transmission. According to this construction, when the ball is in the power transmitting region, the pressing member contacts the first rotating member and is held in a position in which the biasing force of the elastic member is prevented from acting upon the ball.

Abstract: A clutch device for an electric machine tool that is drivable in a fashion selected from the group consisting of a rotary fashion, a percussion fashion, and both with an impact mechanism deliberately disengageable from or engageable with a spindle that drives a plug-in tool, has an intermediate shaft arranged between the spindle and an armature shaft of a drive motor and configured for transmitting drive energy, the intermediate shaft being axially movable so that the electric machine tool is switchable between operating modes through an axial movement of the intermediate shaft.

Abstract: An object of the present invention is to provide an electric screwdriver device having a function for determining that a correct tightening operation has been carried out when the tightening operation has taken a time longer than a reference time predetermined for the tightening operation, characterized in comprising a novel feature for determining the reference time.

Abstract: A power tool generally includes a housing and a motor assembly connected to a transmission assembly. The motor assembly and the transmission assembly are secured against rotation in the housing. A plurality of protrusions extends from a component of the transmission assembly. The power tool further includes an output spindle and a spindle lock assembly that connects the output spindle to the transmission assembly. The spindle lock assembly includes an anvil, an outer ring member and a plurality of roller members. The roller members and the protrusions are disposed between the anvil and the outer ring member. An indicator member extends from the outer ring member. A compliant member connects the outer ring member to an interior portion of the housing. A scale is connected to an exterior portion of the housing, wherein the indicator member moves relative to the scale to indicate a value of torque at the output spindle.

Abstract: The tap driver is configured to be hand-held. It has a tap-holding chuck and a motor to drive the chuck. An external switch rocks forward to rotate the motor in the tapping direction and backward to withdraw the tap. A control circuit causes forward motion of the tap for a predetermined time for the tap to make about one forward turn for tapping. At the end of that time, the motor reverses and rotates the tap outward a fractional turn to break the chips made during tapping. The timer then turns the circuit to drive the motor in the forward direction for another tapping. This action repeats until tapping is complete and the switch is rocked back to reverse the motor to withdraw the tap.

Abstract: An electric impact tool in which a rotating mass rotates in a forward direction to impact upon and transfer torque to an anvil, and rotates in a reverse direction opposite the forward direction in response to such impact. A direction sensor monitors the direction of rotation of the rotating mass, and a controller turns an electric motor on and off during respective forward and reverse rotation of the rotating mass. An energy storing mechanism may be used to absorb energy from reverse rotation of the rotating mass and release the absorbed energy to rotate the rotating mass in the forward direction. A controller may be used to store the angular position of the rotating mass upon each impact and turn off the motor prior to the following impact to avoid energizing the motor during stall.

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

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.

Abstract: A device for the high-speed drilling of boards for printed circuits and the like comprising a support (2), a drill head (11) with associated mandrel (12), and a device for locking and driving a bit (13) in the mandrel, wherein the mandrel is actuated by a compressed air turbine (33) and comprises means (40) for encoding the speed of rotation of the turbine adapted to generate a signal representing this speed, this signal being supplied to a control circuit (61) in order to drive a proportional valve (62) disposed in the circuit supplying compressed air to the turbine as a function of the speed of rotation encoded by the encoder means (40).

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

Abstract: 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 cordless power tool (300) has a transmission (12) having multiple speed ranges In the light torque range, the speed of a motor (8) of the cordless power tool is held constant to hold an output speed of the transmission (12) constant until motor power reaches a predetermined percentage of the maximum watts out of the motor.

Abstract: A hand held motor driven electrically powered tool, in particular a rotary hammer, comprising a spindle (40) for rotatingly driving a tool or bit (68), a spindle rotary drive train (14, 5, 10) for rotatingly driving the spindle (40) and an arrangement for detecting blocking events (16, 17). Blocking events occur when the tool or bit of the tool become rotationally fixed in the material being bored in which case the rotary drive on the spindle from the motor causes the tool housing to rotate in a user's grip.

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

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

Abstract: A power tool includes solid-state motor control. The tool includes a solid state variable speed control signal generator for generating a variable speed control signal, a microcontroller for generating a pulse width modulated (PWM) signal corresponding to the variable speed control signal, a driver circuit for generating H-bridge driving signals corresponding to the PWM signal, and an H-bridge circuit for selectively coupling a motor to a power source in accordance with the H-bridge driving signals.

Abstract: A pulse tool, in particular a pulse nutsetter, has at least one pneumatic drive unit with a drive rotor and a pulse unit driven by the drive unit, wherein a delay-dependent inertial cut-off device is assigned to the drive unit for the interruption of the air feed on acquiring a cut-off pules. A pulse tool of this nature is improved to the effect that it has or facilitates a compact design, a low weight and simultaneously, a fast cut-off by the inertial cut-off device. This is achieved by the inertial cut-off device having at least one cut-off piston for changing the air feed between the open and closed positions and which can be moved relative to the drive rotor and an, essentially annular, inertial body which can turn with the drive rotor. Due to the inertial body, on acquiring the cut-off pulse at least one drive body, essentially radially adjustable relative to the drive rotor, can be deflected due to an internal contour.

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: A hand-held power tool includes a drive element (12), a driven spindle (16), and a slip clutch (14) arranged between the drive element (12) and the driven spindle (16) and including a plurality of coupling bodies (24) engageable with a set of drive side receptacles (26) and a set of driven side receptacles (28), the plurality of coupling bodies (24) disengaging from the drive side receptacles (26) or the driven side receptacles (28) against a spring-biasing force (F), and the driven side receptacles (28) being formed by recesses provided in the driven spindle (16) and opening, with respect to the rotational axis (A), in a radial direction.

Abstract: A power tool including a drive assembly including a first clutch assembly having an engaged configuration, in which the first clutch assembly transfers a drive force from a motor shaft to a spindle, and a disengaged configuration, in which the first clutch assembly prevents the transfer of the drive force. The first clutch assembly can be movable toward the disengaged configuration when a torque exerted on the spindle exceeds a torque limit. The drive assembly can also include a second clutch assembly having an engaged configuration, in which the second clutch assembly transmits the drive force from the motor shaft to the spindle, and a disengaged configuration, in which the second clutch assembly prevents the transmission of the drive force. The second clutch assembly can be movable toward the engaged configuration when the tool element engages a workpiece.

Abstract: A method and a power tool system are provided for performing screw joint tightening using a pneumatic torque impulse power tool that is controlled by a control unit. A torque magnitude and a torque growth are calculated based on signals delivered by an angle sensor, and pressurized air is supplied to the power tool via a flow regulating valve which is successively adjustable between zero and full power flow. The flow regulating valve is controlled by the control unit to deliver a reduced power air flow to the power tool before and during a first delivered impulse, and then to deliver full power flow until a certain torque magnitude or a percentage of a target torque level is reached, whereafter the air supply flow is again reduced until the target torque level is reached, and when the target torque level is reached the air flow is shut off.

Abstract: In a method for controlling a drive (4) of an electrically operated screwdriving power tool (2) during a screwdriving process, a tool holder (14) with a screw bit (16) fastened thereto is acted upon by the drive (4) to drive a fastening element (18) having a contact area (24) into a constructional component (20), with the screw bit movable up to a maximum screw-in value (Dmax) at a speed (D) and a operational torque (MA) generated between the screw bit (16) and the fastening element (18), and after it has been detected that a predetermined triggering screw-in depth (s0) has been reached, the speed (D) is reduced from the maximum screw-in value (Dmax) during a tightening process (AV), and, when it has been detected that a determined end value of the operational torque (MA) is reached, the screwdriving process is terminated.

Abstract: A power tool includes an impact damping mechanism for damping an impact in a direction of rotation of a speed reduction mechanism portion 8.

Abstract: A hand-held power tool has a motor output shaft, a tool driver, and a torque-limiting unit with which a maximum torque transferred from the motor output shaft to the tool driver is adjustable by an operator, the torque-limiting unit including a spring system, the spring system including differently-acting spring elements.

Abstract: In an impact fastening tool, erroneous detection of a strike by a hammer is prevented. The impact fastening tool includes a strike mechanism that transmits a driving force of a motor to an output shaft with an impact force generated by striking an anvil by the hammer, a fastening torque calculator that calculates a fastening torque equivalent to an actual fastening torque generated by the impact forces, a strike detector that detects occurrences of strikes by the hammer, a motor controller that stops the driving of the motor at a time when the fastening torque reaches a predetermined reference value, a current detector that detects current information in an interval of strikes, and a strike judger that judges whether the detection of a strike is real or unreal by using current information. The fastening torque calculator calculates the fastening torque by ignoring the strike judged real by the strike judger.

Abstract: A method for determining the angular displacement of the output shaft (?0) of an impulse nut runner at tightening a screw joint to a predetermined final torque level (Tf) by an impulse nut runner having a motor driven impulse unit (23) with an inertia drive member (27), an output shaft (24) to be coupled to the screw joint to be tightened and an angle sensing device (35, 38) associated with the drive member (27) and arranged to deliver signals in response to the rotational movement of the drive member (27), wherein the total angular displacement of the output shaft (24) in relation to a threshold torque level (Tt) is calculated as a difference between the total angular displacement (?Dtot) of the drive member (27) as a result of a total number of delivered impulses (Ntot) and the angle of the total number of full revolutions minus one full revolution ? (Ntot?1)·360).

Abstract: A rotary impact tool can be used in a work especially precision or finishing of fastening is important. The rotary impact tool comprises a rotary driving mechanism including a driving source for rotating a driving shaft, a hammer fixed on the driving shaft, an output shaft to which a driving force is applied by impact blow of the hammer, a torque setting unit used for setting a fastening torque, a processor for calculating fastening torque from impact blow of the hammer, a rotation speed setting unit used for setting rotation speed of the driving shaft, and a controller for rotating the driving shaft of the rotary driving mechanism in a rotation speed set in the rotation speed setting unit and for stopping rotation of the driving shaft of the rotary driving mechanism when the fastening torque calculated in the processor becomes equal to or larger than a reference value of fastening torque previously set in the torque setting unit.

Abstract: A method of controlling a single-phase linear motor (1) for driving a striking mechanism (2) with a loose coupling (4) between a runner (5) of the linear motor (1) and a striker (6) of the striking mechanism (2) has, within a striking period in which exactly one force impact (K) of the striker (6) is carried out on a tool (8) or an anvil (7), a pull phase (Z) in which the loose coupling (4) contacts a runner-side contact surface (KL) with a one-sided constrained contact and a push phase (D) in which the loose coupling (4) contacts a striker-side contact surface (KS) with a one-sided constrained contact, and a change phase (W) provided between the pull phase (Z) and the push phase (D) in which the one-sided constrained contact changes between the two contact surfaces (KL-KS) along a contactless reciprocating gap (S) in that the runner (5) releases the one-sided constrained contact with one contact surface (KL/KS) in a regulated manner and produces the one-sided constrained contact with the other contact surfac