Abstract: An optical control is disclosed which is particularly suitable for application as a switching device, regulating device or sensor device for a power tool. At least two optical waveguides are provided one of which being configured as a transmitting waveguide is coupled to a light source, a second one of which being configured as a receiving waveguide cooperating therewith is coupled to an evaluation circuitry. Both waveguides cooperate with a control element that is movable at least between two positions in which light signals of different magnitude are transmitted from the transmitting waveguide into the receiving waveguide.

Abstract: A percussion electrical hand-held tool including a housing (10), a percussion element (2) located in the housing, and a planetary gear unit (5) located in the housing (10) for converting a rotational movement (107) of the drive shaft (&ohgr;) of the hand-held tool (8) into a reciprocating movement (&ugr;) of the percussion element (2), with the planetary gear unit (5) including a sun gear (6) changing of a setting (&agr;) of which provides for adjusting of an impact amplitude of the reciprocating movement (&agr;) of the percussion element (2), and control unit located in the housing (10) for adjusting the impact amplitude in accordance with a manual axial force applied to the handle of the hand-held tool (8).

Abstract: A depth assembly for use with a hand-held power tool (2) and including a motorized control unit for adjusting a position of a depth-setting member (3) and connectable with an energy source (4) which supplies power thereto, and a micro-controller (6) for controlling the operation of the control unit (5) and connected with a length-determining sensor.

Abstract: A method of controlling electric- and fluid-powered torque-applying tools to avoid torque overshoot and unwanted joint stresses. During a fastening operation, a controller monitors the peak torque applied to a joint at specified intervals in time and adjusts the speed of the tool appropriately to reach a programmed torque value without overshooting. The method may be applied to arbitrary types of joints and allows the tool to adapt to the characteristics of a joint while a fastening operation is underway, without a separate “learning” or “adaptation” phase.

Abstract: A method and a device for determining the operating time and the operating condition of a hydraulic percussion unit, in particular a hydraulic hammer, having a percussion piston which is guided inside a housing and, under the effect of a controller, alternately performs an operating stroke in an impact direction and a return stroke in a return direction. The method and device obtain information to determine whether the percussion unit requires maintenance operations. Signals are generated during the consecutive, individual operational segments of the percussion unit. The number of signals is proportional to the strokes performed by the percussion piston in one movement direction. The number of the signals is continuously added and is stored as a total number. The current total number of signals can be displayed at least at times for indicating the operating condition of the percussion unit.

Abstract: The present invention provides an automatic tool changer which is adapted to detect the end of the service life of a bearing of a cam follower for systematic replacement of the bearing. The automatic tool changer comprises: a tool changer mechanism (26) including a rotation shaft, a changer arm fixed to the rotation shaft, a cam follower attached to the rotation shaft and having an engagement roller rotatably supported by a bearing, a cam engaged with the engagement roller of the cam follower, and drive for driving the cam; and a controlling section (57) for controlling an operation of the tool changer mechanism (26). The tool changer further comprises a service life end detecting section (9) for counting the number of times of the operation performed by the tool changer mechanism (26) and judging whether or not the count of the number reaches a reference operation number serving as a basis for the detection of the end of the service life of the bearing.

Abstract: An electrically powered impact tool has a removably mountable battery pack which includes an acoustic detection circuit for detecting sounds generated by the impact mechanism in use and, in response to such detection, starts an adjustable time period, at the end of which a relay is actuated for disconnecting the battery of the battery pack from the tool motor for a predetermined time period. This serves as a torque-limiting mechanism where the tool is a torque-applying tool. The time period is adjustable by a dial on the battery pack housing and the control circuitry may be selectively powered through a switch on the battery pack housing.

Abstract: An electrical hand-held power tool including an arrangement for actively damping vibrations applied to the tool handle (2) and arranged between the handle and the hammer mechanism module (3) with a possibility of a limited axial displacement along the percussion axis (A) with respect to the hammer mechanism module (3) and having at least one electromechanical actuator (5a, 5b) surrounded by an elastic spring (8a, 8b), a sensor for sensing vibrations acting on the handle (2), and a microprocessor (7) for dynamically controlling the actuator (5a, 5b) in accordance with the signal generated by the sensor.

Abstract: An electrical hand operated tool driving device (1) for producing an at least partially impacting movement of a tool (11) with an air striking mechanism (2) and a no-load stroke disconnection, which scans the no-load stroke position (9) by a sensor (14) and evaluates it with an assigned control unit (15), and in the event of a no-load stroke, lowers the rpm of an energizing driving mechanism (3) over the control unit (15) to a previously fixed reduced rpm.

Abstract: The present application relates to a pneumatic tool for applying torque to fasteners and a system incorporating such a tool.

Abstract: A hand-held rotary-percussion power tool including 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) including 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: A power tong 10 for making up and breaking apart threaded oilfield tubular connections includes a frame 11 having an open throat 20, a rotary ring 16 having an open throat 22, and a door 24 for closing over the open throat for safety. Hydraulic motor 42 is regulated by a control valve 52 for rotating the ring 16 which in turn rotates the oilfield tubular. A switch 46 responsive to the position of the door 24 controls the flow of air pressure to a cylinder 50, which renders active valve operator 54 which controls valve 52. According to the method of the invention, the door 24 must first be closed so that the switch 46 renders the valve operator 52 active, and the valve operator 52 must be reset once the door is opened before it can be manipulated to operate the motor control valve 52.

Abstract: A hand-held power tool has a machine housing, a drive motor, a tool receptacle, a drive strand accommodated in the machine housing and extending between the drive motor and the tool receptacle, and a detection device for detecting an uncontrolled operational condition of the hand-held power tool, and a blocking device which in case of the uncontrolled operational condition form-lockingly connects the drive strand with the machine housing, the blocking device including at least one locking member which is housing-fixed in a rotary direction of the drive strand and at least one locking member which co-rotates in the drive strand so that the locking member and the blocking member are bringable in engagement with one another, the locking member and the blocking member being bringable in engagement with one another axially in direction of a rotary axis of the blocking member.

Abstract: A power tool system comprises a portable power tool (10), an operation control device (11) including an integrated memory (16) for storing power tool operation data, and an auxiliary memory module (18) normally containing the same power tool operation data as the integrated memory (16) easily connectable and disconnectable in relation to the control the operation control device (11), wherein the auxiliary memory module (18) serves as a removable back-up memory intended to carry operation data from one operation control device to another, notwithstanding the control device being integrated part of a battery powered tool or a separate unit at a main powered tool.

Abstract: The present application relates to a pneumatic tool for applying torque to fasteners and a system incorporating such a tool.

Abstract: A power tool with a linear motor is disclosed. The linear motor has a movable element installing a front tool at its one end and having magnetic poles installed at a fixed pitch along the direction of the movement, magnetic pole teeth installed in opposition to each other and at a fixed pitch along the direction of the movement in a vertical direction of movable element, and a coil for exciting the magnetic pole teeth so that the adjacent magnetic pole teeth and opposed magnetic pole teeth may becomes different poles, respectively. The power tool further has a control circuit for reciprocating the movable element by exciting the coil to work something by using the front tool in the process of this reciprocating movement.

Abstract: A torque control type impact wrench includes a first storage section for storing an ideal upper limit of the pulsed torque for screwing a male screw into a female screw, as a first storage value, a second storage section for storing a driving speed at which a driving section drives a torque producing section as a second storage value, and a control section for causing the driving section to drive the torque producing section at the second storage value and stopping the driving section when the pulsed torque exceeds the first storage value, wherein the control section causes the second storage section to store a value, which is larger than the second storage value, as a new second storage value when the pulsed torque does not reach the first storage value within a given time period after the driving section starts.

Abstract: An electrical hand-held power tool including an electrical drive (2) for transmitting a torque to a working tool (3) rotatable about an axis (a), a sensor (4) for determining an actual torque transmitted to the working tool (3), a control unit (5) for controlling operation of the electrical drive (2), a microcontroller (6) connected with the torque sensors (4) and the control unit (5), and a transceiver (7) for reading in identification data contained in identification data (9) associated with a fastening element (9) located in a corresponding transmission range, container for transporting fastening elements, and identification data carrier, and connected with the microcontroller; and a method of controlling the torque transmitted to the working tool (3).

Abstract: An air powered hydraulic lift system including a hydraulic pump operably connected to the ports of a hydraulic lifting cylinder, the hydraulic pump being driven by an air motor, an air pressure pilot operated valve for controlling supply of hydraulic fluid from the hydraulic pump to the ports of the hydraulic cylinder and an air pressure control valve connected to the air motor and to the air pressure pilot operated valve to supply air pressure to the air motor when air is supplied to the air pressure pilot operated valve.

Abstract: A power tool system comprises a portable power tool (10), an operation control device (11) including an integrated memory (16) for storing power tool operation data, and an auxiliary memory module (18) normally containing the same power tool operation data as the integrated memory (16) easily connectable and disconnectable in relation to the control the operation control device (11), wherein the auxiliary memory module (18) serves as a removable back-up memory intended to carry operation data from one operation control device to another, notwithstanding the control device being integrated part of a battery powered tool or a separate unit at a mains powered tool.

Abstract: The present invention provides an automatic tool changer which is adapted to detect the end of the service life of a bearing of a cam follower for systematic replacement of the bearing. The automatic tool changer comprises: a tool changer mechanism (26) including a rotation shaft, a changer arm fixed to the rotation shaft, a cam follower attached to the rotation shaft and having an engagement roller rotatably supported by a bearing, a cam engaged with the engagement roller of the cam follower, and driving means for driving the cam; and a controlling section (57) for controlling an operation of the tool changer mechanism (26). The tool changer further comprises a service life end detecting section (9) for counting the number of times of the operation performed by the tool changer mechanism (26) and judging whether or not the count of the number reaches a reference operation number serving as a basis for the detection of the end of the service life of the bearing.

Abstract: A hydraulic pump assembly (10) for powering a hydraulic torque wrench (24) is air-powered and has hydro-pneumatic control circuitry (39) which continues operation of an air motor (18) which drives the hydraulic pump (16) for a post-advance period after an advance actuator (55) is deactuated. Operation of the pump (16) is continued for a period sufficient to retract a double-acting torque wrench (24), to permit subsequent advances of the wrench (24) within the post-advance period without restarting the pump (16) or to permit a single acting wrench to be moved from one fastener to the next within the post-advance period without restarting the pump (16). Operation of the pump (16) is terminated when the post-advance period expires if the advance actuator (55) is not reactuated, so as to conserve energy and avoid unnecessary heating of the hydraulic fluid.

Abstract: A dual-mode system for inexpensively operating electrically powered double-insulated devices (12), such as hand-held power tools and appliances. The system includes a cordless battery power module (14) that supplies the power and current demands of the device (12) in a cordless mode or a chopper module (21) that supplies the necessary power and current demands in a physical envelope commensurate in size and interchangeable with that of the battery power module (14). The chopper module (21) is provided with a non-filtered high efficiency converter circuit that allows the chopper module (21) to generate the power and current required by the driven device (12). The inductance of the motor (11) for the driven device (12) is used to filter the output of the chopper module (21). Eliminating the output filter from the chopper module (16) significantly reduces the cost and size of the module (16).

Abstract: A control apparatus for a drilling machine and a drilling method capable of quick adaptation to drilling by drills of various diameters, especially drills of small diameters, and of improving cutting efficiency. The control apparatus includes a cutting condition setting unit for setting the cutting conditions in accordance with the depth of the hole being drilled and a control unit for controlling the rotary speed and movement position of the drill. The cutting condition setting unit defines the regions of the beginning part, the inner part, and the penetration part from the side close to the drill of the workpiece toward the depth direction of the hole of the workpiece in accordance with the depth of the hole when drilling a throughhole.

Abstract: A method and an arrangement for controlling rock drilling on the basis of a pressure acting in a pressure conduit of a rotation motor of a drill rod. In the method, the pressure acting in the pressure fluid conduit of the rotation motor is measured during the rotation when the drill bit does not touch the rock to be drilled, and the control is carried out thereafter on the basis of the difference between the pressure value measured during the drilling and the idle pressure value. In the arrangement, the rock drilling machine comprises a control unit that measures the pressure acting in the pressure fluid conduit of the rotation motor when the drill rod is rotated so that it does not touch the rock to be drilled and stores it in the memory and controls the rock drilling machine during the drilling on the basis of the difference between the pressure value measured during the drilling and the idle pressure.

Abstract: A thermal control circuit (49) for inexpensively protecting the power interface of cordless and dual-mode powered devices (12), such as hand-held power tools and appliances. The powered device includes a motor (11) that is operable in a preselected voltage range. A switch assembly (110) controls the flow of electrical energy to the motor (11). A power module (14, 16) is configured to supply electric power and to mate with the low-voltage DC power tool (12). The power module (14, 16) is adapted to provide a DC voltage in the preselected voltage range suitable for powering the low-voltage DC power tool (12). A case (91) for the power tool (12) has a pre-defined envelope for electrically and mechanically mating with the power module (14, 16). A power interface that includes at least two terminals, electrically couples the power module (14, 16) to the motor (11). The thermal control circuit (49) protects the power interface from damage caused by an overtemperature level.

Abstract: An arrangement in a rock drilling apparatus comprising supports (5) directed toward the rear part of the feed, the supports being moveable by means of support cylinders (6) to support the feed during the drilling operation. The arrangement comprises a pressure detector (9), which is arranged to detect the pressure of the pressure fluid in the support cylinders (6) and to make the control unit supply more pressure fluid to the support cylinders (6) when the pressure drops below a pre-set threshold value.

Abstract: A closed loop control system for a core drilling mechanism automatically controls the penetration rate, the weight on the drill bit, and the torque load applied to the drill string, and maintains all three at or below preselected maximum values. The closed loop control system incorporates a controller that receives sensed information and generates corresponding control signals to control the penetration rate and thus the weight on the drill bit and the torque load through a servo valve in a hydraulic drive circuit. One or more sensors are provided to sense the penetration rate of the drill bit, and are coupled with the controller. Similarly, sensors are provided to determine the weight on the drill bit and the torque load applied to the drill string.

Abstract: The rock drill (9) includes a reversible rotary motor (10) and a percussion unit (11) with a percussion valve (17). Rotary unit and Percussion unit (11) are operated via separate valves (39, 46) in a control unit (34). The percussion frequency of the percussion unit (11) is coupled to the rotation rate of the rotary motor (10) in such a way that the percussion unit (11) stops automatically when the rotary motor (10) comes to a standstill. The coupling is achieved by employing a fluid driven assembly without a mechanical clutch between the rotary motor (10) and the percussion valve (17). When disassembling the drill rods a jammed thread can be shaken loose with the percussion unit (11) be manually bypassing the fluid coupling. The same is also possible in case the drill rods becomes jammed in the drill bore. With the described embodiment a simple, space-saving and cost-effective construction is achieved which is versatile in application.

Abstract: An adjusting device for an unbalance vibrator with adjustable centrifugal moment. The invention concerns specifically the specialised category of vibrators in which each unbalance shaft has its own motor (110, 112, 114, 116) and no transmission system is provided for connecting the minimum of four unbalance shafts. A novel way of hydraulically actuating the motors is described for ram vibrators of this type provided with four hydraulic motors (110, 112, 114, 116). This involves connecting two motors (the ones allocated to the two unbalance shafts which always rotate synchronously counter to one another even during adjustment) in parallel to their own respective hydraulic circuits. Each of the two hydraulic circuits (118, 120) has its own pump (P1, P2) and the pressures in the forward flow and/or back flow lines can be adjusted independently from the outside by a control and regulation device (126, 128) in such a way that they can be used to set the centifugal moment in a predeternmined manner.

Abstract: When a start SW 3 is pressed, a one-shot multivibrator circuit 15 turns on and releases a pulse. The pulse is transmitted to a self-hold circuit 16 which in turn stays in self-hold mode and releases an H level output continuously until it is reset. This cause a transistor 17 to turn on and actuate a ram downward movement relay R1. When the ram arrives at the lower limit of its movement, a lower LS 4 is opened causing a self-hold circuit 21 to produce an H level signal in accordance with an output of a one-shot multivibrator 18. The H level signal from the self-hold circuit 21 is delayed by a delay circuit 22 and turns on a transistor 23. As the result, a ram upward movement relay R2 is actuated. Because of the function of the one-shot multivibrator circuit 15, the ram will not restart when the start SW 3 is continuously depressed. The delay circuit 22 contributes to the longer operational life of a directional valve switching mechanism.

Abstract: A percussion blow added manually operable drilling tool, such as a hammerdrill, has a housing (2) containing an electric motor for rotating a tool bit chuck (9) about its axis, a control device (C) for controlling the rpm of the chuck (9) operated by the electric motor (3) which is activated by a switch (5) located on the exterior of the housing (2), and a percussion blow mechanism for periodically applying axially directed blows to a bit (10) secured in the chuck (9). The electric motor (3) is coupled to a device (12) for measuring the reaction torque. The control device (C) is connected to an evaluation unit (E) which is connected to the device (12) for measuring the reaction torque so that the rpm of the chuck can be regulated from maintaining the measured reaction torque at a maximum.

Abstract: A hand power tool has a machine housing, a drive motor accommodated in the machine housing, a drive train connected with the drive motor and provided with a tool receptacle for rotation of a tool insertable in the tool receptacle, a detecting device for detecting an uncontrolled operation of the hand power tool by detecting a blocking of the tool in a workpiece with a resulting impact-like turning of the machine housing, a blocking device provided for the drive train and releasable by the detecting device, the locking device having a locking toothing arranged in the drive train and a blocking member movably supported in the machine housing and form-lockingly engagable in the locking toothing so as to non-rotatably fix the drive train relative to the machine housing, the detecting device being formed so that it produces an electrical release signal in an uncontrolled operation, the blocking device being releasable by the electrical release signal, and further has electromagnet device actuatable by the release

Abstract: A power tool including an inertia responsive element. The power tool comprises a housing, a motor supported by the housing and adapted to be connected to a power source, an output element supported by the housing and selectively coupled to the motor, the motor imparting motion to the output element, and an inertia responsive element for disconnecting the output element from the power source if movement of the housing is greater than a predetermined threshold. In one embodiment, the power tool is a hand held power tool having a handle, and the inertia responsive element disconnects the output element from the power source should the handle move at a rate greater than a predetermined rate. In another embodiment, the power tool is a stationary power tool, such as a drill press. The housing of the stationary power tool includes a base for supporting the stationary power tool on the workpiece.

Abstract: A hydraulic pump assembly for powering a hydraulic torque wrench is air-powered and has hydro-pneumatic control circuitry which continues operation of an air motor which drives the hydraulic pump for a post-advance period after an advance actuator is deactuated. Operation of the pump is continued for a period sufficient to retract a double-acting torque wrench, to permit subsequent advances of the wrench within the post-advance period without restarting the pump or to permit a single acting wrench to be moved from one fastener to the next within the post-advance period without restarting the pump. Operation of the pump is terminated when the post-advance period expires if the advance actuator is not reactuated, so as to conserve energy and avoid unnecessary heating of the hydraulic fluid.

Abstract: In forging hammers, according to the present invention, more than one inlet valve is employed and more than one exhaust may be employed. The force of impact for a particular blow is controlled by the number of valves employed and the timing of the opening and closing of those valves relative to one another. By making successive adjustments with different combination of valves, the controls may be calibrated so that the same ram force may be repeated. Knowing the valve settings required to produce differing amounts of force, it is possible to program the settings into the memory of a computer, so that when a particular impact force is selected the appropriate valve timing will be reproduced and the desired force obtained. It is also possible to set up a sequence of blows of differing selected force, setting each blow using the computer memory.

Abstract: Apparatus for assembling fasteners includes a fastening wrench operated by a first operator and having interchangeable sockets of different sizes for engaging nuts of different sizes. The nuts are required to be tightened to different torque values on their respective bolts. When the first operator removes a socket from a socket tray in preparation for attaching the socket to the fastening wrench, a signal is sent to a controller which determines the torque value associated with that socket size. When the fastening wrench reaches the specified torque value during the tightening operation, the controller automatically shuts the fastening wrench off. The apparatus also includes a second wrench, operated by a second operator, for engaging the heads of the bolts to prevent them from turning during the tightening process. During the tightening process the second operator may not be in communication with the first operator.

Abstract: A hand held power tool includes a motor coupled to an output element and an inertia switch operative to disable the output element upon movement of the tool at a rate greater than a determined rate. The inertia switch disables the output element by open circuiting the motor or uncoupling the output element from the motor.

Abstract: A battery powered palm ratchet tool including a hemispherical palm grip. The palm grip has an upper body with a gripping ring and an under side interconnected to a stop. The upper body encases a battery and a motor powered by the battery. The upper body has a plurality of teardrop-shaped sections interconnected by a plurality of ridges. The plurality of ridges bulge outwardly beyond the teardrop-shaped sections and create an enhanced gripping surface on the upper body of the palm grip. The palm grip has an axial opening within the upper body and stop for receiving a shaft. The shaft is rotatably mounted within the axial opening and driven by the motor. The shaft is compressible within the axial opening for activating the motor and actuation of the shaft. The palm grip is positioned within one hand of a user for use on torquing an item.

Abstract: A separate thumb accessible pushbutton operated circuit revises the power operated tube nut wrench at a reduced speed to intercept a home stop wherein after the wrench is automatically shut off on the sensing of current rise in the motor on stall to avoid over stress and unnecessary heat buildup.

Abstract: An auto cycle pump in accordance with the invention includes a housing having a reservoir for storing hydraulic fluid. A hydraulic pump in the housing provides hydraulic flow. A directional valve has neutral, advance and retract positions to respectively restrict hydraulic flow, direct hydraulic flow to an advance port and direct hydraulic flow to a retract port, the ports for hydraulic connection to the hydraulic tool, in use. Fluid conduits are provided connecting the pump and reservoir to the directional valve. A flow switch detects return flow from the directional valve to the reservoir. A pressure sensor sense hydraulic pressure from the pump. A dump valve is operatively connected to the pump for directing hydraulic flow back to the reservoir when the directional valve is in the neutral position. A control is operatively connected to the pump, the directional valve, the flow switch and the pressure sensing means for controlling operation of the auto cycle pump in automatic mode of operation.

Abstract: A power tool clutch assembly is provided. A first spindle is configured to rotate in a gear case. A drive clutch element is fixed to the first spindle. A second spindle rotates independently of the first spindle. An output clutch element is fixed to the second spindle. An intermediate clutch element is positioned between the drive and output clutch elements, rotatable and slidable relative to the second spindle. A compression spring is provided between the intermediate and output clutch elements. A clutch housing supports the clutch components. The clutch housing and clutch components all can be removed from a power tool gear casing for easy service.

Abstract: A drill rig includes a main engine which drives a drilling spindle through a clutched transmission. A protective cage surrounds the spindle when the transmission is in gear to prevent workmen from being injured by drilling tools. An auxiliary drive motor operates the spindle for a limited number of revolutions when the transmission is in neutral and the protective cage is open to permit workmen to rotate the spindle to add and remove augers, couple and uncouple drilling rods, and perform other necessary tasks.

Abstract: Rock drilling device for drilling with a drill string comprising a set of tubes (1) and a set of rods (2) arranged centrally in the set of tubes.

Abstract: An improved hydraulic cylinder with a hydraulic impact hammer integrated into the cylinder rodhead of the hydraulic cylinder is provided. The hydraulic hammer is positioned inside a central chamber of the cylinder rodhead such that the impact piston can deliver at least one blow along the longitudinal axis of the cylinder rod to create an additive pulse of force.

Abstract: A drill rig which is equipped with one or more safety mechanisms designed to prevent injuries to rig operators. In a first embodiment, the safety mechanism includes a barrier which is shiftably mounted to the rig and surrounds the drilling tool when the barrier is in the closed position. The barrier includes a key member which must be fitted into a sensor-equipped keyhole in the rig for the drilling tools to operate. A brake may also be connected to the drill spindle to stop rotation until the barrier is closed. In a second embodiment, a sensor is connected to a delay timer. The sensor is also connected to the clutch and transmission and alerts the operator that the clutch is disengaged but the transmission is not in neutral by sounding a warning buzzer after a predetermined time. If the operator fails to actuate a disconnect switch by shifting to a neutral position within a second predetermined time, a second delay timer activates to shut off the engine.

Abstract: A system for automatically measuring piling results of a piling operation. The system comprises a pile numbering unit, an operational date setting unit, a reference sinking amount setting unit, an average times of hammering setting unit, a stop signal generating unit, a start signal generating unit, a pile sinking displacement measuring unit, a pile perpendicularity detecting unit, a hammering sound detecting unit, a central processing unit, a data printer, a signal display, an informing speaker, a pile perpendicularity display, and a measuring arm for mounting the pile sinking displacement measuring unit and the pile perpendicularity detecting unit.

Abstract: A tightening tool includes a hammer for impacting on an anvil which drives a nut etc. A microphone is provided for converting impact sounds of the hammer on the anvil into an electric signal. A counting device counts the number of pulses of the electric signal. A setting device is provided for setting a set number of impacts to be obtained. A switch device compares the counted number of pulses with the set number and stops a motor for driving the hammer when the number of pulses coincides with the set number.

Abstract: A control system for a hydraulic percussion mechanism (6) is based on the continuous measurement of the striking rate (z) of the striking piston, or on the continuous measurement of the striking rate (z) of the striking piston together with the quantity per unit time (Q.sub.e) of the hydraulic driving medium coming into the percussion mechanism (6). One, or possibly both, of these parameters is measured from outside the percussion mechanism itself. The control system is configured in such a way that the internal resistance of the percussion mechanism or the hydraulic pump which powers it is increased if there is an increase in the striking rate (z) or the ratio z/Q of the striking rate to the incoming stream rate beyond respective limit values.

Abstract: A portable screw fastener driving tool is driven electrically from a solid state inverter and intended to be coupled to any selected one in a set of screw fastener engaging members, each demanding a drive enabling tightening of the engaged fastener by parameters (e.g. torque, angle, speed) specific to its size or type. Code elements are provided on the members in a binary code pattern specific for each member. Sensors on the tool read the code pattern on the member connected to the tool and serve it electrically to a decoding unit which transforms the read binary pattern to signals adapted to control the inverter the way the member demands.