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

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

Abstract: A rock drilling apparatus with several actuator units, a user interface control unit, and at least one control means connected to the user interface control unit for controlling the functions of the rock drilling apparatus, and for each actuator unit, a control element connected under the control of the user interface control unit for controlling the operation of the actuator unit in accordance with control signals provided by the user interface control unit, and a method for controlling the rock drilling apparatus. When the control element of an actuator unit of the rock drilling apparatus turns faulty, the control element of another actuator unit is connected to control the first actuator unit when the other actuator unit need not be controlled.

Abstract: Apparatus for controlling a drilling machine to drill a series of parallel holes, where the drilling machine comprises a carrier vehicle movable over the terrain, a boom mounted on the vehicle for movement side to side on the vehicle, a mast carried on an outer end of the boom and movable about two separate axes relative to the end of the boom, includes a first sensor responsive to an azimuth angle relative to the earth's magnetic north direction and two additional sensors, which are used to measure the two inclinations relative to two vertical planes transverse to and longitudinal of the boom. The sensor system is mounted in an housing on the mast close to the longitudinal center of the mast and offset to the side. A controller calculates from the sensed values of the azimuth and inclination angles required target angles for the mast for drilling each hole.

Abstract: A pneumatic screw driver includes: a tool body; a nose portion; a main air chamber; a hammering cylinder; a driver bit integrally combined with a hammering piston in the hammering cylinder; an air motor; a valve housing provided in an air passage between the main air chamber and the air motor; a stop valve piston provided in the valve housing; a stop valve stem coaxially provided with the stop valve piston; a timer chamber connected to the hammering cylinder; a first pipeline and a second pipeline respectively formed at upper and lower positions in a lower portion of the stop valve stem; and a upper end proximal portion of a contact member provided slidably in a driving direction. The upper end proximal portion of the contact member is provided engageably with the stop valve stem. The first pipeline and the second pipeline are arranged so as to close the first pipeline after closing the second pipeline by moving the stop valve stem upward from a bottom dead center.

Abstract: A combustion-engined setting tool (10) for driving fastening elements in a workpiece includes a combustion chamber (11), a drive piston (15) displaceable in a piston guide (17) and driven by expanding gases produced in the combustion chamber (11), and a device for returning the drive piston (15) in its initial position as a result of pressure difference between chambers formed on opposite axial sides of the piston head (115), and including a pump (20).

Abstract: An electric power tool includes a motor, a reduction mechanism, a driving unit, a bearing unit, a housing, a speed changing unit, a power switch, and an operation detecting unit which detects a reduction ratio changing operation performed by the speed changing unit to control electric power supplied to the motor. The reduction mechanism transfers the rotating power of the motor, and the driving unit transfers the rotating power of the reduction mechanism to a tip end tool. The bearing unit rotatably supports the driving unit, and the housing accommodates the motor, the reduction mechanism, the driving unit and the bearing unit. The speed changing unit changes a reduction ratio of the reduction mechanism, a power switch for turning on and off a power source of the motor.

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

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

Abstract: In a hydraulic system for mining equipment and a method of adjusting the power of a rock drill machine, at least one mining actuator used for detaching rock is connected to a dedicated separate hydraulic circuit having a special hydraulic pump. The power of the mining actuator is adjusted by changing the hydraulic power generated by the separate hydraulic circuit of the hydraulic pump.

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

Abstract: A power tool, such as a pipe cutter, includes a rotatable cutting head assembly, an electric motor connectable to a rechargeable battery, and a controller. The controller is configured to monitor the state of charge on the battery, compare the state of charge to one or more thresholds, and prevent or limit operation of the power tool when the state of charge is less than or equal to one or more of the thresholds. In some embodiments, the threshold includes the state of charge required to cut a pipe, the state of charge required to return the cutting head assembly to a home position, and a state of charge indicative of an overdischarged condition of the battery. In some embodiments, the controller is configured to detect when the pipe cutter has completed cutting the pipe and returns the cutting head assembly to the home position.

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 method and a software product for positioning a drilling unit in a rock drilling rig, and a rock drilling rig. The drilling unit (5) included in the rock drilling rig (1) is manually displaced towards a starting point (14) of a hole (19) to be drilled next. A control unit (11) in the rock drilling rig (1) performs after the manual displacement (A) an automatic positioning (B) accurately to the starting point in order to initiate drilling.

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

Abstract: A power tool includes a power unit with a rotation motor, and a reduction gearing, wherein the reduction gearing includes a set of interchangeable gearing units attachable one at a time to the power unit and having different operational characteristics including different total gear ratio and torque capacity. Each gearing unit has an electronic identification device programmed with data specific for each gearing unit, such as total gear ratio, torque range, and relating to compatibility of the gearing unit with a certain power unit. The power unit includes an electronic operation control unit programmed with a number of different operation parameter sets each intended for a specific one of the gearing units, and a circuit for communicating with a gearing unit attached to the power unit to determine whether there is compatibility and which parameter set is applicable.

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

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

Abstract: An air compressor includes: a tank portion for reserving compressed air used in a pneumatic tool; a compressed air generation portion for generating compressed air and supplying the compressed air to the tank portion; a drive portion including a motor for driving the compressed air generation portion; a control circuit portion for controlling the drive portion; and a pressure sensor for detecting pressure of the compressed air reserved in the tank portion. The control circuit portion includes a unit for controlling the rotational speed of the motor multistageously based on a detection signal output from the pressure sensor.

Abstract: A drill slide (1) for a drilling apparatus, the slide (1) adapted to slidably support a drifter (6), the slide (1) comprising a telescopic shaft (2) having a first elongate member (3) telescopically slidable with respect to a second elongate hollow member (4); a first rail mounted to or integral with the second elongate hollow member (4) upon which the drifter (6) travels along; and wherein a second removable rail (7) is adapted to be fitted adjacent to the first elongate member (3) in an extended configuration, where the second rail (7) is end to end with the first rail (5) thereby allowing the drifter (6) to slide along the first (5) and second rails (7).

Abstract: Methods and apparatus to apply axial force to a packer in a downhole tool are described. In one described example, an apparatus to apply an axial force to an inflatable packer associated with a downhole tool includes a sleeve slidingly coupled to a body of the downhole tool and an end of the packer. An inner portion of the sleeve is sealed against the body of the downhole tool to form a chamber, and the chamber is fluidly coupled to a pump associated with the downhole tool to receive a pressurized fluid to cause the sleeve to apply an axial force to the packer.

Abstract: The present invention aims to provide a screw fastening machine for reliably switching and changing a driving force transmitting path with the seating on a work as a reference. According to the screw fastening machine in which a first pulley is connected to a first driving mechanism for applying high speed low torque drive to a drive shaft, a second pulley is fixed in an integrally rotatable manner to a transmission shaft for connecting the drive shaft, and an endless belt is interposed between the pulleys to obtain a configuration for high speed low torque drive, a second driving mechanism for low speed high torque drive is arranged on an extension of the transmission shaft, and the second driving mechanism performs the drive until a final fastening torque is reached when a screw component is seated on the work and the stall state is achieved, the final fastening torque is always reliably obtained and the work time is reduced without waste.

Abstract: A positioning structure of the transmission device of a screw fastening apparatus is disclosed. The transmission device includes a stopping block, gear body and a braking body. An elastic rim is positioned between the lateral side of the stopping block and the inner face of a mobile seat. The gear body is H-shaped structure and one lateral side is provided with a plurality of slanting holes for corresponding protruded blocks, and the other lateral side is provided with a plurality of engaging holes. One side of the seat plate of the braking body is protruded with a shaft for mounting with the gear body, and the stopping block and the elastic rim are mounted to the hole on the mobile seat, and the seat plate is provided with a plurality of engaging blocks to engage with the engaging holes of the gear body. The other lateral side of the seat plate corresponding to the center of the shaft is a slot to accommodate a spring urging a square-shaped board.

Abstract: A hammer drill comprising: a motor; a drive transmission capable of operating in at in at least a rotary mode and a reciprocating mode; a mode change mechanism; a switch which, when closed, provides power to the motor; and a mechanical lock-on mechanism which, when locked mechanically holds the switch closed to maintain the power to the motor. Additionally, the hammer drill includes a first sensor, which indicates the mode of operation of drive transmission; and a second sensor which indicates whether the lock-on mechanism is locked; and a controller which is capable of interfering with the operation of the motor, when the controller detects that the drive transmission is in the rotary mode of operation and the lock-on mechanism has been locked.

Abstract: An electronic control, for automated earth drilling using a pneumatic hammer-operated bit, preliminarily weighs a drill string, and, during drilling, automatically maintains a desired weight on the bit, and also maintains a constant rate of drilling progress by regulating drill string rotation speed. The weight on the bit is automatically maintained at a fraction of the pre-established desired weight as the air pressure in the supply to the pneumatic hammer builds up to an operating level. The control detects voids and broken formations by monitoring air pressure and torque respectively, and responds by reducing the weight on the bit. The control automatically raises the drill bit though a short distance as the drill head reaches the lower limit of its travel, pauses until the air pressure drops, and then raises the drill string to a position for insertion of a new length of pipe.

Abstract: A method of generating a stress pulse, and an impact device. In the method, pressure fluid is fed as pressure pulses to a working chamber residing between the frame of the impact device and a tool such that the resulting force presses the tool towards the material to be processed. The impact device comprises a working chamber and device for conveying pressure fluid as pressure pulses thereto such that a force is produced between the frame of the impact device and a tool to press the tool towards the material to be processed.

Abstract: A novel displacement instrument that can be used to measure the density or modulus of an aggregate pier upon which a multistory building or parking garage can be built. The aggregate piers are often 35 feet or deeper. These aggravate piers are constructed by adding lifts of approximately 12 to 18 inches of aggregate at a time and tamping it into the pier forming hole. Each lift of aggregate is being tamped or struck by a force of approximately 15,000 psi or greater. The displacement instrument allows aggregate piers to be constructed having a density or modulus that is consistent from the bottom of the hole to the top of the hole. The displacement instrument would be mounted on the side plate of a hydraulic breaker that is mounted on the end of a boom of a crane. The displacement instrument need not be permanently installed on the side of the hydraulic breaker and it is freely removed and installed on another crane.

Abstract: The rock drilling rig comprises a first control unit (8) arranged on a carrier (1) and a second control unit (9) arranged to a rock drilling apparatus (4). The first control unit (8) and the second control unit (9) communicate with each other by means of a first data communications link (10). The rock drilling apparatus (4) has one or more sensors (11, 12, 15), the measuring results of which are processed in the second control unit (9) and only then transmitted to the first control unit (8) that controls actuators regulating the operation of the rock drilling apparatus (4). Correspondingly, the rock breaking machine, such as a breaking hammer, comprises one or more sensors (11, 12, 15) and a control unit (9).

Abstract: This invention is generally directed towards a system designed to assist the rig operator by alerting him/her that the air pressure is too low to be using the drum clutch, to provide a log for studies on rig operation technique, and to provide a training tool for rig operators. If the pressure on the clutch bladder is above a predetermined range, the clutch is allowed to engage. If the signal is below the range, the clutch is assumed to have not been engaged. If the signal is within the range, the clutch is not allowed to engage and the rig operator is notified of the problem.

Abstract: The invention relates to a rock drilling arrangement and a method and program for controlling rock drilling on the basis of specific energy consumption. The specific energy of drilling is the quantity of energy used per a unit of length of the drilled hole. Not only the used impact energy, but also the energy used by at least one other sub-process is taken into account when determining the specific energy. Rotation energy is typically included, but feeding energy and flushing energy can also be considered. Drilling variables are adjusted so that the specific energy is of a predetermined size.

Abstract: A nose (5) of an air impact driver (1) is mounted with a slidable contact nose (12) and by the contact nose, a contact valve (23) upward therefrom is operated to switch. An AND circuit operated to pilot an air motor controlling pilot valve (39) and a piston controlling pilot valve (41) is constituted by a trigger valve (8) operated by a trigger lever (9) and the contact valve (23). When the contact nose is pressed and the trigger lever is pulled, the air motor controlling pilot valve and the piston controlling pilot valve are switched to starting positions to start the air impact driver.

Abstract: A rock drill includes a string of components interconnected by screw threads and connected to a shank. A percussion piston is reciprocated against the shank during a drilling operation, while a support device applies axial support to the rear of the shank, to enhance the drilling action. When the components are being unscrewed, the percussion piston is actuated to strike the rear end of the drill string, after the support device has at least partially released the axial support of the shank, to enable tensile stress to be generated in the components by the percussive impacts to facilitate unscrewing of the components.

Abstract: A compact and light-weight pneumatically operated screw driver providing high speed screw fastening with high operability. A rotary member rotationally driven by a pneumatic motor includes a main rotary member made from a plastic material and a sliding segment fixed to the main rotary member. A rotation slide member is axially slidably movable relative to the rotary member and is rotatable together with the rotation of the rotary member. A shut-off section is provided on which the rotation slide member is rotationally seated when the rotation slide member is moved toward the shut-off section. The rotation slide member is made from an elastic material. A sleeve like piston having a seal ring in sliding contact with a cylinder is provided. The seal ring shuts off a supply of compressed air to the pneumatic motor only by the seating of the rotation slide member onto the shut-off section.

Abstract: A method and a computer program for controlling a drilling cycle in a rock drilling apparatus, and a rock drilling apparatus. In accordance with the invention, each drilling unit in the rock drilling apparatus is monitored during a drilling period, and a drilling sequence of a control unit in the rock drilling apparatus is updated at predetermined intervals during the drilling period. The total time of the drilling and the time elapsed for different operations can be registered. In addition, according to an embodiment, the drilling sequence is changed during updating, if changes occur in the drilling conditions during the drilling period.

Abstract: A pneumatic motor-controlled valve of a screwdriver is installed between an air guide hole of a pneumatic motor and a main air valve gate in the screwdriver. A valve hole is formed on a guide seat and is communicated to an air guide hole of the motor. A plug is formed on an outer wall of a cylinder; and the cylinder is movably mounted within the guide seat. A lower spring resists against the cylinder. At least one ventilating hole is formed on a wall of the cylinder for communicating the valve hole to one of the upper valve opening and the lower valve opening of the main air valve gate. The plug drives the cylinder to actuate with the descending and rising of the piston valve so as to open or close the valve hole of the guide seat, thereby, the rotation of the motor is controlled.

Abstract: A method and an equipment for controlling the operation of a rock drilling apparatus, which rock drilling apparatus comprises a percussion device for producing impact energy to a tool of the rock drilling apparatus, a rotating device for rotating the tool in a drill hole, a feeding device for feeding the tool in the drill hole and a flushing device for supplying flushing agent through the tool and the bit for flushing loose drilling waste from the hole. The feed force and the percussion power are determined and the relation between the feed force and the percussion power is adjusted to a targeted operation area within an upper and a lower limit.

Abstract: The invention is based on a hand power tool, in particular a drill hammer and/or a chipping hammer, having a striking mechanism (14) capable of being driven in a housing (10) by an electric motor (12), via which an insertable tool (18) situated in a tool mount (16) is capable of being driven in an impacting manner, and having a sensor unit (30) via which a characteristic value for a no-load position can be detected. It is proposed that, when a no-load position is detected via a motor control unit (22), the electric motor (12) and, therefore, the striking mechanism (14) can be actively decelerated.

Abstract: The invention provides a bolting installation apparatus comprising a base having a pair of parallel cylindrical rods held between two end plates; an intermediate carriage slidably mounted on said rods; a drilling unit carriage having at least one first rod and at least one second rod spaced apart from said first rod; a drilling unit slidably mounted on said second rod and said intermediate carriage slidably receiving said first rod of said drilling unit carriage; at least one moving means to move each of said base, said intermediate carriage and said drilling unit carriage relative to each other.

Abstract: The rock drilling rig comprises a first control unit (8) arranged on a carrier (1) and a second control unit (9) arranged to a rock drilling apparatus (4). The first control unit (8) and the second control unit (9) communicate with each other by means of a first data communications link (10). The rock drilling apparatus (4) has one or more sensors (11, 12, 15), the measuring results of which are processed in the second control unit (9) and only then transmitted to the first control unit (8) that controls actuators regulating the operation of the rock drilling apparatus (4). Correspondingly, the rock breaking machine, such as a breaking hammer, comprises one or more sensors (11, 12, 15) and a control unit (9).

Abstract: The present invention relates to a percussion electrical hand-held tool having an electronic control unit (5) for controlling at least one power parameter of the electrical tool, and a substantially flat force sensor for controlling operation of the electronic control unit (5) and arranged sliding displacement-free for sensing a press-on force (F, F1) applied by a user in an operational direction of the electric tool, without being displaced, between at least two, associated with each other, press-surfaces (7a, 7b) extending at least partially transverse to a percussion axis (A) of the electrical tool.

Abstract: This invention provides a roof bolt installation apparatus including a drill stabilizing mechanism including a base having a cylindrical bore therein, and a stabilizing rod extendable from the base and slidably located in the bore. The rod has a distal end, and a drill stabilizing end plate is mounted on the rod distal end. The roof bolt installation apparatus also includes a drilling unit which is adapted to rotatably carry a drill, the drilling unit being slidably mounted on the drill stabilizing mechanism, and a mechanism for moving the drilling unit along the drill stabilizing mechanism. The roof bolt installation apparatus also includes a drill depth control device including a base, a top adapted to engage the mine roof, and at least two bars connected between the drill depth control base and the drill depth control top. The bars pass through openings in the drill stabilizing plate.

Abstract: An excavation apparatus especially useful when mounted on backhoes and other lighter vehicles used in the construction industry. The excavation apparatus does not require a winch for letting out and retracting its cable nor a reel for storing retracted cable which reduces the weight of the excavation apparatus, lowers its cost while facilitating both operation and servicing. The apparatus has a kelly assembly housing which houses an outer kelly section, and an extendable innermost kelly section adaptable for attachment of a tool. More than one extendable kelly section can be used. A rotary table rotates the kelly sections. A support structure supports the rotary table and the housing. A frame allows the housing to slide relative to the frame in a direction parallel to the axis of the assembly. A downcrowd mechanism, supported by the frame, downcrowds the support structure relative to the frame.

Abstract: Power tool (1) may include a drive source (22). A device for generating an elevated torque, such as a hammer (4) and anvil (2), may be operably coupled to the drive source. Further, a trigger switch (48) may energize the drive source. Preferably, a sensor (30) detects when the hammer has begun to strike the anvil and generate the elevated torque. A control device (38) communicates with the sensor, the trigger switch and the drive source. Preferably, the control device may control the drive source according to either a measurement mode or an automatic stop mode. In the measurement mode, the control device preferably activates the drive source when the trigger switch is switched from the OFF position to the ON position, and stop the drive source when the trigger switch is switched from the ON position to the OFF position.

Abstract: The invention concerns an hydraulically powered mechanism of the kind having a piston assembly which is arranged to be driven by hydraulic fluid acting on it in a working zone and an item of equipment which is to be driven by the piston assembly. The piston assembly presents a face which acts at an interface against a complemental face on the item of equipment. A fluid passage is provided to supply hydraulic fluid from the working zone to the interface for lubrication purposes. In a specific application of the invention it may be used in the rotary indexing mechanism of an hydraulically powered, typically a water-powered, rockdrill.

Abstract: A hand-held rotary-percussion power tool includes an electrical drive (2) for generating a torque transmittable to a boring tool used with the power tool for forming blind bores, a hammer mechanism (3) for applying impacts to the boring tool, control device (7, 7′, 7″) for controlling operation of at least one of the electrical drive (2) and the hammer mechanism (3), and an electronic depth stop (4). The depth stop include a sensor (5) for contactless, distance measuring of a depth of a blind bore, and a computation unit (6) for generating a signal indicating that a sensed measurement value (M) corresponds to a set value of the depth of the blind bore, and connected with the control device (7, 7′, 7″).

Abstract: It is an object of the present invention to overcome various drawbacks of a conventional oil pulse wrench by using an electric motor, to reduce a reaction force and to fasten a screw with high precision. To achieve the object, the invention provides a control method of a screw fastening apparatus using an electric motor as a rotation driving source, the method comprising the steps of; intermittently supplying current pulse DP to the motor, detecting an actual torque at predetermined time intervals, maintaining a current value when a detected torque value does not exceed a maximum value of past detected torques value and increasing the current value by a predetermined amount when the detected torque value exceeds the maximum value of the past detected torque value, and stopping the supply of the current pulse DP when the detected torque value reaches a target value TQJ.

Abstract: Two guide members cooperatively constitute a chuck portion for holding a screw head. Opening and closing of the chuck portion is regulated depending on a mutual position between a machine body and a member into which a screw is driven. Guide pin portions of respective guide members engage with a stopper portion of a push lever until a screw is driven to a predetermined depth. The chuck potion tightly holds the screw head until a screw fastening operation is substantially finished, thereby suppressing the lifting of a machine body.

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

Abstract: A piercing apparatus compact in size having a decreased number of hoses is suited for use as an iron runner port-opening machine for a blast furnace or the like furnace in an iron mill.