Abstract: Method and apparatus for improving the efficiency of the rotating cutter of a tool by converting at least part of the rotational torque applied to the cutter to repeated rotational impact forces.

Abstract: An improved electronic controller for the motor of a high-speed spindle attachment used in conjunction with a cnc milling machine. The controller comprises preventative circuitry that protects the spindle assembly of the attachment from overload accruing as a result of relatively moderate increases in torque demand during use. The controller senses the power level being used by the motor while it causes high-speed spindle rotation, and when it identifies a power consumption rate by the spindle that exceeds the operator pre-set maximum level determined to be safe for avoiding catastrophic spindle damage, the electronic controller sends a signal back to the computer controlling the axes of the cnc milling machine that is sufficient to slow, pause, and/or stop the feed-rate.

Abstract: A numerical controlling unit includes: an inputting part into which a machining program is inputted; an analyzing part that analyzes the machining program to generate an instructed spindle rotational speed and calculates a spindle load ratio of a load applied to a spindle under a machining condition according to the machining program to a spindle load caused when the workpiece is machined: and a distributing part that generates, based on the machining program, a distribution amount per unit period inputted into a feed-axis servo driver. A spindle-rotational-amount-command outputting part receives the instructed spindle rotational speed and outputs a spindle-rotational-amount command for commanding a rotational amount per unit period which is inputted into a spindle driver. A cutting-load-for-judgment calculating part calculates a reference torque value based on the spindle load ratio, the distribution amount, and the spindle-rotational-amount command.

Abstract: A CNC tapping machine includes a spindle to which a tap is attached and a spindle motor for rotating the spindle. The load torque acting on the spindle motor that is detected when performing a tapping procedure without a workpiece is stored in a memory as referential, torque data. During a tapping procedure, a detection device detects the load torque acting on the spindle motor. A computer computes the difference between the load torque defected by the detection device and the referential load torque and uses the difference as the cutting load acting on the tap. As a result, the cutting load torque acting on the tap is accurately detected.

Abstract: A tool-driving device (1), which is particularly provided for machine tools, has an internal drive (9), which serves to drive a tool. Also provided is a control device (36), which detects the movement of the tool-driving device (1) and correspondingly controls its drive (9). The tool-driving device (1) can thus be controlled independently of the other tool-machine controls.

Abstract: An adaptive control system for adaptively controlling a turning operation performed at a work piece by a turning tool adjusts a controlled input operation parameter F to maintain an output operation parameter &Dgr;M substantially at a predetermined value &Dgr;Mo to compensate variation of the output operation paramemeter &Dgr;M caused by the variation of at least one operation condition B=B (t). The system comprises a sensor (8) of the output operation parameter &Dgr;M for providing a signal Uc proportional to a current value &Dgr;Mc and an adaptive controller (10) for determining a value Fc to which the input operation parameter F should be adjusted, as a function of kUc, where k is a signal transmission coefficient which comprises an invariant signal transmission coefficient component ko inversely proportional to &Dgr;Mo.

Abstract: A programmable command module for inputting a surface foot rating parameter into a device for controlling the spindle speed of a cutting tool. Based upon the surface foot rating, the proper speed of the spindle is determined with respect to a particular cutting tool parameter, such as the tool's diameter. The spindle speed setting is transmitted to an AC inverter which in turn controls the operation of an AC motor for rotating the spindle at its proper speed. Alternatively, a second embodiment of the present invention would include a programmed memory provided with the surface foot rating of a plurality of materials. Once the type of material, the type of tool operation, as well as the diameter of the cutting tool is inputted into this embodiment, the proper RPM speed of the spindle would be determined.

Abstract: An electrical hand operated tool driving device (1) for at least partially rotationally driving a tool has a tool chuck (3), at the front end of a housing (2) along with an operating handle (4) for an operator's hand (11), with the handle located adjacent to the tool chuck. A bearing surface (8), for supporting the electrical hand operated tool driving device (1) on the forearm associated with the operator's hand (11), is positioned in the rear end region of the housing (2) spaced from the tool chuck (3).

Abstract: A motor-operated hand-held device (1), such as a drilling device, has a rotary spindle 6 located in and projecting out of a housing (2). Rotational movement of a driving motor (8) is transmitted to a tool (7) situated in an end of the rotary spindle (6). A safety device (11) within the housing (2) prevents deflection of the housing about an axis (A) of the rotary spindle (6) in the event the tool (7) becomes suddenly jammed. The safety device (11) can be activated by a detection device (12) if the tool becomes jammed. The safety device (11) is located inside the housing 2 adjacent to the rotary spindle (6) and is formed of at least two component parts which cooperate in frictional engagement in the event the device is activated. One of the component parts is connected to the housing (2) and the other is connected to the rotary spindle (6).

Abstract: A device for and method of preventing accidents caused by jamming of a tool when working with hand-operated machine tools driving a rotating tool, especially hammer drills, is outfitted with an interrupter device for interrupting the action of the driving motor on the rotating tool depending on the operating state detected by a deflection sensor (1). The device includes a computer unit (R) in which a probability for an expected accident is determined from the sensor signals supplied by the deflection sensor (1), and in that the interrupter device (5, 6) can be activated when a preset accident probability is exceeded. In the method rotational movement values are determined from the measurement signals supplied by the deflection sensor (1), these rotational movement values are converted in a computer unit (R) by nonlinear logic operations to form accident probabilities and activating the interrupter device as soon as the estimated accident probability exceeds a preadjustable threshold value.

Abstract: One of two arms is mounted adjacent one end thereof for rotation and axial adjustment on a cylindrical column which projects vertically upwardly from a generally flat, rigid base. The second arm is rotatably connected adjacent one end to the opposite end of the first arm, and has mounted in its opposite end a rotatable spindle which is connected at its upper end to the drive shaft of a reversible electric motor that is secured on the second arm, and which is disposed to have a tool bit secured releasably to its lower end. The first arm is manually adjustable vertically on the column, and each arm can be releasably locked against rotation. The direction of rotation of the motor can be reversed by a switch mounted on the second arm and its speed can be adjusted by a potentiometer, the rotatable handle of which is mounted on the second arm adjacent the motor reversing switch.

Abstract: A machine tool includes a spindle having a cutting tool for cutting a workpiece. For fault detection, a control unit of the machine tool detects a value representing a torque applied on the spindle while the spindle is stopped in a state the cutting tool is engaged with the workpiece. The control unit further compares the detected value (representing a torque) with a predetermined threshold thereby to determine that a fault has occurs. Since the detection of the value representing a torque is performed while the spindle is stopped, the detection is free from the effects of acceleration or deceleration of the spindle.

Abstract: A motor-operated hand-held device (1), such as a drilling device, has a rotary spindle (6) located within and projecting out of a housing (2). Rotational movement of a driving motor (8) is transmitted to a tool (7) secured to the end of the rotary spindle (6). A safety device (11) within the housing (2) prevents a deflection of the housing about an axis (A) of the rotary spindle (6) in the event the tool (7) becomes suddenly jammed. The safety device (11) can be activated by a detection device (12) if the tool (7) becomes jammed. An overload slip clutch (10) is provided in the drive (9) between the driving motor (8) and the rotary spindle (6). The safety device (11) is arranged in series with the overload slip clutch (10) and is located in the drive (9) adjacent the overload slip clutch (10). When activated, the safety device (11) couples the housing (2) with the drive (9) for the rotary spindle so that the housing (2) and the drive (9) are fixed with respect to rotation relative to one another.

Abstract: An apparatus for controlling a tapping-drilling machine is disclosed in which holes can be formed by means of drilling tools, and threads can be formed by means of tapping tools. A worm is elongately formed on a spindle, and a worm wheel which is meshed with the worm is secured by a lateral shaft. At the leading end of the lateral shaft, there is installed a brake. In the preferred embodiment of the present invention, the electronic type brake is employed, and the electric current flowing through this brake is adjusted, so that the velocity of the vertical movement of the spindle sleeve (which is defined to be the ratio of the vertical moving distance to the revolutions of the spindle) can be automatically adjusted.

Abstract: A threading apparatus is capable of eliminating a rise delay in the feed velocity due to friction resistance and can perform high-precision threading even in high-speed tapping. A feed servo amplifier is controlled to operate using one of a plurality of gains. A gain setter sets the plurality of gains, which include a high gain, which is high enough to overcome static friction resistance, and a normal gain. A gain changer selects one of the plurality of gains for the feed servo amplifier. In particular, the gain changer selects the high gain during a start period of tapping operation and then selects the normal gain after the start period. Therefore, a rise delay in the feed velocity due to friction resistance during the start period of the tapping operation can be compensated for. After the start period, the normal gain is selected. Thus, high-precision threading can be performed over the course of the tapping operation with no errors.

Abstract: A method of and an arrangement for preventing accidents during operation of a manually-operated machine tool having a rotatable toolbit and a drive motor for driving the toolbit, wherein an operational condition of the toolbit is determined with a rotational motion sensor, a time constant is selected, a maximum forecast rotational angle at an end of a time period determined by the selected time constant is calculated on a basis of a rotational motion signal generated by the sensor, and transmission of drive motion from the drive motor to the rotatable toolbit is interrupted as soon as the calculated, forecasted rotational angle exceeds a value of the maximum allowable rotational angle.

Abstract: An automatic drilling machine has an electric drilling unit on which a cylindrical cutter is rotatably mounted. The drilling machine includes a drill motor for rotating the cutter and a feed motor for linearly moving the cutter for the purpose of drilling into materials such as concrete. The current flowing through the drill motor before a drilling load is imposed thereon is detected for a microprocessor to determine the type of the cutter being used. The drill motor is driven at a rotation speed suitable for the cutter being used and the feed motor is driven at a speed such that the rotation speed of the drill motor thus set is maintained unchanged. Particularly, the drill motor is driven at a reduced rotation speed from the start of drilling until a predetermined drilling depth is reached to reduce chatter vibration which may otherwise be generated if the drill motor is driven at a regular constant speed from the beginning of drilling until the end.

Abstract: A hand-held machine tool has a housing, a tool rotatable about a rotational axis, a motor provided with a gear unit and driving the tool in rotation about the rotational axis, the gear unit having at least one rotating part which is arranged so as not to be axially parallel to the rotational axis of the tool, a bearing supporting the rotating part of the gear unit, and a sensor arranged at the bearing so that the sensor lies in an effective region of bearing forces which are produced by a moment of occurring gyroscopic effect when the housing rotates around the rotational axis of the tool.

Abstract: An improved numerically controlled machine tool is provided by resiliently coupling an independent drive mechanism to a toolholder which in turn is fitted to the numerically controlled machine. The drive mechanism in turn is coupled to a working tool used for drilling, tapping, milling or other machine functions. The drive mechanism and the toolholder are resiliently coupled together so that they may be relatively displaced one with respect to each other depending upon the amount of vertical force being through the working tool applied to the drive mechanism tending to urge the drive mechanism either toward or away from the toolholder. The torque, power and/or rate of rotation of the working tool is controlled as a function of the relative displacement of the working tool with respect to the toolholder along a predetermined axis of coupling between them.

Abstract: In drilling control method and apparatus for making holes through a composite workpiece made of a plurality of materials having different machining properties, the workpiece is first drilled at a feed speed and a rotational speed of a drill which are selected. When the drilling of the workpiece is initiated, the amounts of the feeding speed and the rotational speed are detected by a feed speed sensor and a rotational speed sensor, respectively, and thrust force applied to the drill during the drilling is also detected by a thrust sensor. The detected feed speed and the rotational speed of the drill are compared in a comparison unit with optimum values which are adapted to the detected thrust force.

Abstract: A control unit capable of driving a compound lathe so that an end face of a rotating workpiece can be tapped. The control unit (100) comprises first and second control circuits (110, 120) for controlling the rotation of first and second spindles (10, 20) respectively fitted with the workpiece (60) and a tapper (70). At start of tapping operation, the second control circuit executes position loop control in accordance with a deviation (.epsilon.) between position feedback signals (PCC1, PCC2) related to the two spindles, thereby equalizing rotational speeds of the two spindles, and then causes the second spindle to rotate at a speed higher than that of the first spindle by a tapping speed in accordance with the deviation (.epsilon.

Abstract: The states of contact switches are switched when a mode switch is turned on. If the drilling operation is effected by means of a drill motor in this state, an oscillation signal which is repeatedly set to "H" and "L" in a preset period corresponding to an output of an oscillator is supplied to the control terminal of a firing pulse generator. The firing pulse generator interrupts supply of the control signal to the control terminal of a triac in the above preset period based on the oscillation signal supplied to the control terminal thereof to interrupt supply of an AC power source from a commercial AC power source to a bridge-type rectifier so as to intermittently drive a feed motor which is energized by an output of the rectifier in the above preset period. As a result, the drill motor can be intermittently fed towards a to-be-worked object by means of the feed motor, and, when the feeding operation is interrupted, a cutting operation can be instantaneously stopped and swarf can be cut apart.

Abstract: An apparatus for controlling an operating stroke of a reciprocating member to be reciprocated by a drive motor. The apparatus includes an encoder adapted to generate pulses each of which corresponds to a predetermined incremental distance of movement of the reciprocating member, a counter for counting the pulses during movement of the reciprocating member in a forward direction, a device for converting the operating stroke into the number of the pulses corresponding to a multiple of the incremental distance of movement, and a residual distance which is a difference between the operating stroke and the multiple, a device for converting the residual distance into a corresponding residual time, and a device for commanding the drive motor to stop an operation thereof causing a further forward movement of the reciprocating member, when the residual time has elapsed after a count of the counter is equal to the above-indicated number of the pulses.

Abstract: A positive feed drill and method of operation is disclosed for drilling through a workpiece consisting of a softer overlay material on a harder base material. The positive feed drill includes a high-speed air motor and a low-speed air motor and will start and drill through the softer overlay material at the high speed but will shift to the low speed when the drill senses that the thrust on the drill bit has increased because the drill bit has contacted the harder base material. After drilling through the harder base material, the drill bit will shift to the high speed because the drill senses that the thrust on the drill bit has decreased. The drill will retract from the workpiece at high speed and will shut off. Control apparatus is provided to control the flow of air to the high-speed and low-speed air motors. Sensing apparatus senses the thrust on the drill bit and sends a signal to the control apparatus to switch between the air motors.

Abstract: A drill control organization includes a cam member rotatably mounted within spaced support blocks, wherein a forward support block is mounted within a side surface of a handle and coextensively therewith. A dial plate is mounted to a forward support shaft of the cam, including an indicator handle to effect selective rotation of the cam to provide a selective abutment surface in cooperation with a rear surface of a speed control trigger of a drill organization.

Abstract: Disclosed is a tapping control system capable of performing tapping work with high accuracy and reliability in a manner such that rotation of a tap by means of a digital spindle motor (1) is synchronized with axial drive of the tap by means of a servomotor (2).A digital control circuit (5), used to drive the spindle motor, is supplied with a speed command from position control means (4). The speed command is based on a distributed pulse from an interpolating circuit (3a) for linear interpolation in accordance with the pitch value of a screw to be worked, and a feedback signal indicative of the rotational position of the spindle motor. Also, a servo-circuit (12) for the servomotor is supplied with a distributed pulse from the interpolating circuit. Thus, the two motors are driven synchronously.According to an aspect of the present invention, the tapping work is performed in a fixed cycle such that forward and reverse rotations of the two motors are repeated to reciprocate the tap.

Abstract: A thread cutting machine is provided with a control system in which, according to one aspect, the rotation of the spindle is controlled in the synchronous manner following up the feed amount of the spindle head and the rotation instruction is computed in accordance with the feed deviation, In another aspect, the feed of the spindle head is controlled in the synchronous manner following up the rotation of the spindle and the feed instruction is computed in accordance with the rotation deviation. In a further aspect, the rotation instruction is operated in accordance with the feed speed and the feed acceleration. In still a further aspect, the feed instruction is computed in accordance with the rotation speed and the rotation acceleration. In the preferred embodiments disclosed herein, the synchronism between the rotation of the spindle and the feed of the spindle head can be remarkably improved with various control modes, thus achieving the high speed thread cutting working with high accuracy.

Abstract: A hand-held device, such as a hammer drill, has a replaceable axially extending holder for a working tool. The device includes a sensor and a signal transmitter for adjusting its operating characteristics. The holder has through openings containing locking elements and control elements. The locking elements and control elements are radially displaceable within the through openings by a locking sleeve. The position of the locking sleeve in the axial direction of and relative to the holder determines the cooperation of the sensor and the signal transmitters.

Abstract: The trust exerted on a drill bit is sensed and employed to determine the speed at which the bit is driven. A controller for the drill compares the thrust to a predetermined threshold value and in response to the comparison emits a control signal which shifts a transmission in the drill into high or low speed. After each shift, a number of thrust samples are taken in order to compute an average thrust for different strata of the material being drilled. At the completion of drilling each hole, the average thrusts for the hole are used to recalibrate the shift threshold value. In this manner, the shift threshold is adjusted to compensate for drill bit wear. The sensed thrust is also compared to a bit reject threshold value to determine when the bit is too dull for proper drilling.

Abstract: A hand-held device with a holder for a working tool has a sensing mechanism for automatically initiating different operating modes. Different configurations of working tools inserted into the holder can be sensed by sensing elements in the form of balls. The balls cooperate with pivotal levers and a sensor for producing switching signals for initiating a switching operation.

Abstract: A drive motor connected to a drill bit serves to actuate the drill bit. An electric current is allowed to flow through the drive motor to activate the drive motor. A mechanism serves to feed the drill bit with respect to a workpiece. The current flowing through the drive motor is sensed. A device stores a value of the current which is sensed when the drill bit is out of engagement with the workpiece. A determination is made as to whether or not a drilling process is completed in accordance with a value of the present sensed current and the stored value of the sensed current.

Abstract: A thrust and torque sensor is provided for an automatic drill so as to result in an efficient drilling operation for laminated materials. Sensors are placed in one instance in conjunctioln with a spindle and in another instance to a shaft in the drive train so as to sense the thrust and torque placed on the spindle. In a preferred manner, a yoke with strain gauges is connected to a bearing race on the spindle to sense thrust and strain gauges are placed on a beam connected to a shaft to sense torque. Signals from the strain gauges are then employed by a computer to control the drill.

Abstract: A tap drive unit for machine tools, which is coupled to the machine-head of the machine tool such as a machining center, includes a driver detachably coupled to a main spindle of the machine tool so as to be rotated with the main spindle, a support member for rotatably supporting the driver, the support member being fixedly mounted on a stationary portion of the machine tool when the driver is coupled to the main spindle of the machine tool, a tubular guide member supported by the support member so as to be concentric with the driver, and a rotational shaft on one end of which a tap is mounted. The guide member is axially moved when a load larger than a predetermined value acts on it. An internal thread is formed in the inner periphery of the guide member. An external thread is formed in the outer periphery of the rotational shaft so as to be threadably engaged with the internal thread.

Abstract: A thread cutting machine where the rate of advance of the thread cutting tool is controlled by means of a control system whereby the rotation of the tool and its rate of advance toward the workpiece are both used to control the position of the cutting tool.

Abstract: A threading attachment is provided in the tooling area of a multiple spindle machine tool, wherein the tap holder is rotated by a motor which has an infinitely variable speed within a given range and includes a first speed for advance movements to tap workpieces. This advance movement is provided by a motive power unit to move the tap holder in the advance movement and also in a retract movement at the completion of tapping. The motor has a second variable speed condition to back the tap out of the workpiece. This threading attachment is modular in construction to permit it to be physically mounted in any of the spindle positions of the multiple spindle machine tool and to be capable of being utilized with machine tools of different frame sizes. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Abstract: A machine tool setting device and control system are provided. The machine tool setting device sets the machine tool tip at a predetermined distance above a work piece by detecting when the machine tool tip intercepts an optical beam. The control system allows for the drilling of multi-ply work pieces wherein the multi-plies comprise different thicknesses and hardnesses. The drill bit translational velocity and rotational velocity are continuously controlled for optimization depending upon the type of material and thickness as a hole is drilled through the work piece.

Abstract: A shiftable transmission drive with assured input-output relationship includes a drive motor-transmission mechanism wherein a drive motor drives an output shaft at different rates through a shiftable transmission, and wherein the output shaft is always connected with the drive motor through the shiftable transmission. The output shaft is thus always under control and its position precisely known. The shift position of the gears is known. Shifting is directed at predetermined positions by a microprocessor when the transmission is stopped or at low speeds of rotation. The drive is a direct drive or alternatively a gear ratioed drive.

Abstract: An apparatus for conducting high-speed drilling bone tissue of varying density causing proportioned variations in the speed of the drill bur. A means is provided for automatically sensing the momentary bur rotational speed and producing either a visual or audible signal represented of the changing speed and its companion density.

Abstract: In an automatic fastening machine comprising a frame, drilling assembly carried by the frame for drilling a fastener receiving hole in a workpiece and an arrangement carried by the frame for installing a fastener in the hole drilled in the workpiece, the drilling assembly comprising a drill spindle having an axis of rotation and a drilling tool at one end thereof and rotatably mounted in a ram movable on the machine frame toward and away from the workpiece, the improvement of a brushless synchronous a.c. servomotor including an output shaft having an axis of rotation and an arrangement for connecting the motor directly to the drill spindle with the axis of rotation of the motor shaft coincident with the axis of rotation of the drill spindle. There is also provided a fan on the frame and positioned to direct cooling air onto the motor.

Abstract: A thread cutting machine where the rate of advance of the thread cutting tool is controlled by means of a control system whereby the rotation of the tool and its rate of advance toward the workpiece are both used to control the position of the cutting tool.

Abstract: A power drill and automatic control system includes a drill spindle for mounting a rotary cutter, a spindle rotation drive including a drive motor and an associated rotation drive mechanism operably connected to the spindle to rotate it; a spindle feed drive includes a feed motor and an associated feed drive mechanism operably connected to the spindle to feed it in a forward direction toward a workpiece and in a reverse direction retracting it away from the workpiece. Control is provided to start and stop the spindle rotation drive motor and the spindle feed motor independently. Control is provided for the spindle rotation drive to vary the rotational speed. Control is provided with the spindle feed drive to vary the rate of feed of the spindle. A sensor with the spindle rotation drive senses operational torque of the spindle. Another sensor with the spindle feed drive senses thrust force on the spindle and the associated cutter.

Abstract: A hand tool machine, in particular a drill machine, has a feeler device for determining the diameter of a tool element to be used with the hand tool machine. For measuring the tool elements prior to insertion into the clamping element of the hand tool machine, a feeler device is provided which is arranged separately from the clamping element and is connected with an indicator. The diameter determined by the feeler device is administered to a control unit which is controlling the driving motor. The control unit can also receive in addition further information concerning the material to be treated by means of an input device. In view of the measuring value with regard to the diameter of the tool element and the administered information concerning the material, the optimum rotary speed for the tool element and consequently for the driving motor is determined and adjusted.

Abstract: A tool for maintaining ice baskets associated with a nuclear reactor system. The frame of the tool includes a platform which is disposed on a lattice support structure surrounding a selected and isolated basket. The tool includes an electric drill mounted for vertical reciprocation, in parallel axial relationship with the ice basket, and plural, selectively connectable auger shaft sections having a continuous helical fin thereabout which are connected in succession between the drill and a rotary drill bit, for drilling a hole of the required length, down through the ice within the ice basket. The drill then is maintained at an upper, vertically fixed position and a funnel positioned about the auger; ice chips or flakes are fed into the funnel while the drill is driven in reverse rotation, the auger conveying the ice to the bottom of the ice basket for filling lowermost voids and for filling successively higher voids as the auger is withdrawn.

Abstract: An electric drill safety device is provided for dynamically braking a drill when there is contact between the drill bit and an electrically conductive material. A first direction voltage is applied to the motor winding to turn the motor forward. When contact is detected between the drill bit and an electrically conductive material, voltage to the windings is discontinued momentarily and thereafter a reverse direction voltage is provided to the motor windings for a predetermined time.

Abstract: An automatic shift drill for rotationally driving a bit into a laminated workpiece at one of two speeds according to the depth of the bit in the workpiece is disclosed. A cam block element has flag sections and gap sections corresponding to the various layers of the workpiece. The cam block element is mounted on a spindle of the drill to move in translation with the bit. A vent element has an orifice which is adapted to be closed when it is adjacent to one of the flag sections and open when it is adjacent to one of the gap sections. Shifting means responsive to pneumatic pressurization changes the rotational speed of the bit from one speed to the other speed. The orifice vents the shifting means when it is adjacent to a gap section to drive the bit at the appropriate speed through the corresponding layer and seals the shifting means when it is adjacent to a flag section to drive the bit at the other speed appropriate for the layer corresponding to the flag section.

Abstract: An apparatus for angularly orienting a machine tool spindle (24) to a keylock position includes a resolver (39) which is directly mounted on a shaft (13) of a spindle drive motor (12), the spindle (24) rotating synchronously with the shaft (13) through a shiftable gear train. Resolver (39) is connected to update a register (45) so that the count shown by the register indicates the angular position of shaft (13) with respect to the spindle head (11) as the shaft rotates. During synchronous rotation, a target (33) revolving with the spindle causes a proximity sensor (32) on the spindle head (11) to generate a pulse when the spindle (24) is in a known orientation relative to the spindle head (11). When a pulse occurs a data processing unit (46) of a numerical control circuit (42) compares the actual count in register (45) with a number of possible count values contained in a data storage table (44).

Abstract: A drilling machine provided with an electromagnetic base comprises a first control system by which a warning device is actuated and/or a feed motor for automatically advancing an electric drill toward a workpiece is stopped when a load on the electric drill exceeds a prescribed first reference level while at work. A second control system further provided on the drilling machine is adapted to have the feed motor and/or the electric drill stopped when the load thereon is further increased and reaches a second reference level higher than the first reference level to assure high safety.

Abstract: A blind rivet setting tool for setting threaded rivet nuts comprises a threaded pin for engaging the rivet, and a rotating mechanism to screw the nut on to the threaded pin before a rivet upsetting operation, and to unscrew the pin from the nut after the upsetting operation. The upsetting operation is performed by imparting an axial movement to the pin. The rotating means is actuated to screw the pin into the nut by applying an axial pressure to the tool and the pin while, when the axial load on the tool is relieved, the rotating mechanism automatically rotates the pin in the opposite direction, for disengagement of the pin from the rivet.

Abstract: A drilling machine including an electric drill being selectively fixed at a desired angle with respect to a workpiece and a manual feed handle for moving the electric drill toward and away from the workpiece. A control circuit for the electric drill is provided having a sensor member being operatively connected in said control circuit for detecting a load applied on the electric drill. An alarm member is operatively connected in the control circuit for sending out a signal when a load signal exceeding a first reference level is detected. A switch is operatively connected in the control circuit for deenergizing said control circuit for the electric drill when a load signal exceeding a second reference level is detected.

Abstract: To provide for, selectively, control of the speed of a tool, such as a drill or boring tool coupled to an electric drill or boring machine motor, independently of the setting of a multi-speed transmission, speed of the tool is sensed by a contactless transducer (4, 7), one part of which is coupled to the chuck (1, 2) and the other to the housing (H) of the tool, to provide speed signals which incorporate the transmission ratio of the gear (G, 66). Speed control, for example under a command signal (40; 50), then will control the actual speed, regardless of the transmission setting, with the torque deliverable by the motor being controlled by the selected gear. The diameter of the drill or other tool bit is sensed also by the transducer, if coupled to the chuck jaws, to vary the output signal from the transducer as a function of chuck jaw diameter.