Abstract: A clamping chuck is provided for clamping palettes having a clamping spigot. The clamping chuck includes a receiving opening for the clamping spigot and a clamping device that includes an actuating piston displaceable between an initial position and a locking position for actuating clamping members for clamping the clamping spigot in the receiving opening. The clamping chuck includes a monitoring line that is acted upon pneumatically and leads from an inlet to an outlet. the receiving opening includes a conical insertion region, into which at least one control hole connected to the monitoring line emerges, the control hole being closed by the clamping spigot. A valve device is arranged between the inlet and the outlet of the monitoring line to vary the flow of a fluid through the monitoring line depending on the position of the actuating piston.

Abstract: A main spindle device for a machine tool that checks the seating of a tool holder using compressed air, wherein the main spindle device for a machine tool comprises: a main spindle that has a distal end face in close contact with a flange end of the tool holder; an annular recess that is formed on the distal end face of the main spindle so as to be covered by the flange end of the tool holder; an air supply flow channel that is linked to the annular recess and that supplies compressed air to the annular recess; a compressed air source that supplies air to the air supply flow channel; and a pressure detector that detects the pressure of the compressed air in the air supply flow channel. The annular recess has a first section and a second section that is deeper than the first section, and the air supply flow channel is opened to the second section.

Abstract: A universal manufacturing vise jaw plate for use on a machine tool with a vise fixture, and configured for real-time operational data collection and analysis. The vise plate comprises a combination of acoustic and vibration sensors with a plate for cutting tool monitoring applications.

Abstract: An angle grinder includes a housing, a drive unit configured to drive a usage tool, a sensor device configured to provide a rotation parameter, and a control unit configured to evaluate the rotation parameter to detect a clamped state of the usage tool. The sensor device has a yaw rate sensor configured to provide the rotation parameter in accordance with a rotational movement of the housing. The control unit triggers a safety mode in accordance with the rotation parameter or throttles the rotational speed and/or torque of the drive unit.

Abstract: The invention relates to a machining center for work piece machining. The machining center comprises a machine frame, a machine spindle driven by a motor and rotatably arranged on the machine frame, and a group of machine tools that can be exchanged on the machine spindle. The machine tools comprise a coupling shaft that is compatible with a holder of the machine spindle. Furthermore, a rotary transmitter for electric energy is provided, having a stator fixed to the machine in a stationary manner and a rotor rotating along with the machine spindle. It is claimed as novel that the rotary transmitter comprises at least two transmission paths for electric energy which can be selected according to the electric power to be transmitted and the rotational speed of the spindle to be set and which can be activated in the coupled state of the machine tool.

Abstract: An apparatus for indicating a drilling thrust of a hand-operated drill includes a thrust-indicator assembly for attaching between a drill motor and a drill chuck of the hand-operated drill to indicate the drilling thrust. A method of indicating a drilling thrust asserted on a hand-operated drill includes: attaching a thrust-indicator assembly between a drill motor and a drill chuck of a hand-operated drill; and indicating, with the thrust-indicator assembly, a drilling thrust asserted on the drill chuck.

Abstract: A spindle control system for a milling machine is provided. The milling machine includes a column, an overarm, a spindle for mounting a cutter, a first motor mounted on the column for driving movement of the overarm, and a second motor mounted on the overarm for driving rotation of the spindle. The spindle control system includes a distance sensor and a temperature sensor, each to be mounted on the overarm and to be disposed proximate to the end portion of the spindle. The spindle control system further includes a central control unit for determining a compensation parameter based on the displacement sensed by the distance sensor and the temperature sensed by the temperature sensor, and for controlling movement of the overarm by the first motor through a compensation distance based on the compensation parameter to compensate for at least one of the cutter deformation and the spindle deformation.

Abstract: A cordless magnetic drill is disclosed. The drill comprises a control unit, a motor which is connected with the control unit, a gearbox which is connected with the motor, a power source which is connected with the control unit, and a magnetic base. The gear box is used for regulating the output rotation speed of the motor. The power source is used for supplying power to the motor. The magnetic base can be an electromagnetic chuck, an electro-permanent magnetic chuck, a permanent magnetic chuck or the combination of a permanent magnetic chuck and an electromagnetic chuck. The control unit is used for controlling the operations of the motor and the power source and establishing or cutting off the connection between the power source and the motor. The cordless magnetic drill of the present invention is convenient and very safe to use.

Abstract: An improved pneumatic ADE-machine with a built-in logic has a clutch in the power transmission chain between a first drive gear and a second driven gear. The clutch includes two clutch parts (D, F), whereof a first part (D) is axially biased by a spring (C). Movable elements (E) are arranged between the clutch parts, which transfer the rotation from the first to the second clutch part, and an actuator (H) is arranged in connection with the first spring biased clutch part (D). When a feed force on a drill during drilling exceeds the biasing force of the spring, the movable elements displace the spring biased clutch part axially, which triggers the actuator (H) to send a corresponding signal to the machine logic.

Abstract: The invention relates to a protection device for a motor spindle (1) arranged in a housing (2), particularly of a machine tool, having an inner ring (6) fixedly joined to the motor spindle (1) and an outer ring joined to the housing (2). The inner ring (6) is arranged in the outer ring (7) in a way permitting axial motion and a tilting motion, and is placed under elastically resilient preload against the outer ring (7) by means of preloading members (8).

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

Abstract: A drill has a tubular outer housing and a tubular inner housing. The inner housing is movable between extended and retracted positions. A pneumatic motor with a chuck mounts to the inner housing. Air pressure is delivered to annular pistons to cause the inner housing to extend and retract. Also, an annular hydraulic chamber with a variable orifice bypass controls the rate of feed. A processor records the total number of holes being drilled as well as recording the time duration for each hole.

Abstract: An electric drill having a function for preventing drilling of unexpected oblique hole. Further in the electric drill, when the direction of drilling is displaced in drilling work using the electric drill, it is sensed automatically to stop the drilling. The electric drill (1) performs drilling in the direction perpendicular a workpiece (7) and have a tilt sensor (10) mounted on a tilt sensor mounting surface (8) defined in parallel to the ground surface. When the rotation axis (C) of the drill positioned perpendicular to the surface of the workpiece is tiled to an angle equal to or greater than a predetermined angle, the tilt sensor (10) senses the tilt shutoff a drive current of the electric drill.

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

Abstract: An electric drill having a function for preventing drilling of unexpected oblique hole. Further in the electric drill, when the direction of drilling is displaced in drilling work using the electric drill, it is sensed automatically to stop the drilling. The electric drill (1) performs drilling in the direction perpendicular a workpiece (7) and have a tilt sensor (10) mounted on a tilt sensor mounting surface (8) defined in parallel to the ground surface. When the rotation axis (C) of the drill positioned perpendicular to the surface of the workpiece is tiled to an angle equal to or greater than a predetermined angle, the tilt sensor (10) senses the tilt shutoff a drive current of the electric drill.

Abstract: An electric drill having a function for preventing drilling of unexpected oblique hole. Further, in the electric drill, when the direction of drilling is displaced in drilling work using the electric drill, it is sensed automatically to stop the drilling. The electric drill (1) performs drilling in the direction perpendicular a workpiece (7) and has a tilt sensor (10) mounted on a tilt sensor mounting surface (8) defined in parallel to the ground surface. When the rotation axis (C) of the drill positioned perpendicular to the surface of the workpiece is tilted to an angle equal to or greater than a predetermined angle, the tilt sensor (10) senses the tilt to shutoff a drive current of the electric drill.

Abstract: A gemstone drill is of the drill press type which includes a motor suspended and slidably affixed between upstanding vertical telescoping rods. A drill bit is affixed to a spindle which is a direct extension of the motor shaft which is in parallel alignment with the rods. A body of the motor includes a cylindrical spindle housing extending downwardly from the bottom of the motor body adjacent the drill bit. The rods are extensible from tower sleeves mounted directly to a base which has a top support surface enclosed by a transparent containment cover. The door is moveable between open and closed positions to gain access to a clamping mechanism releasably attached to the support surface that holds the stone to be drilled. The containment cover, when closed, includes a circular aperture at the top which closely receives the spindle housing.

Abstract: A tapping method for performing a tapping process in a punch press includes engaging a front end of a tap provided at a tapping tool attached to a rotating mold indexing device rotatably provided at the punch press with a prepared hole formed in a workpiece. When the front end of the tap is engaged with the prepared hole, a control motor of the rotating mold indexing device is rotated positively to rotate the tap positively. When it is detected that the control motor of the rotating mold indexing device has rotated a determined number of times, positive rotation of the control motor is stopped and the motor is rotated reversely, thereby to detach the tap from the prepared hole of the workpiece.

Abstract: It is an object of the present invention to prevent recurrence of an overload condition after occurrence of the overload condition, thereby improving operability and safety in a drilling device. A motor 12 for rotating a drill is connected to an AC power source 10 through a motor control unit 28, a current detector 30, and a power switch 36. A magnet 16 is also connected to the AC power source 10 through the power switch 36 and a full-wave rectifier 18. The motor control unit 28 rotationally drives the motor on the basis of a signal sent from a main control unit according to a state in which a motor start switch 38 is on. The main control unit 14 controls the motor control unit 28 to gradually reduce a supply voltage to the motor 12 when the motor 12 becomes overloaded, to gradually increase the voltage to the normal power supply condition when the overload condition is vanished, and to stop power supply to the motor 12 if the overload condition continues for a predetermined period.

Abstract: A compact drilling system capable of improving working efficiency. The drilling system includes a drilling machine and a compressor. A control circuit controls performances of a drill motor in the drilling machine and an air compression motor in the compressor based on the detection result of a pressure sensor that detects a pressure within an air tank provided in the compressor. When one of the motors is activated, the other motor is not allowed to be operated and only when the drill motor is activated, compressed air is supplied from the air tank to the drilling machine. An electrical socket is provided in the compressor. A power cord extending from the drilling machine can be connected to the socket.

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

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

Abstract: An electric drill having a function for preventing drilling of unexpected oblique hole. Further, in the electric drill, when the direction of drilling is displaced in drilling work using the electric drill, it is sensed automatically to stop the drilling. The electric drill (1) performs drilling in the direction perpendicular a workpiece (7) and has a tilt sensor (10) mounted on a tilt sensor mounting surface (8) defined in parallel to the ground surface. When the rotation axis (C) of the drill positioned perpendicular to the surface of the workpiece is tilted to an angle equal to or greater than a predetermined angle, the tilt sensor (10) senses the tilt to shutoff a drive current of the electric drill.

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

Abstract: The invention relates to a measuring device 5 of the type which detects the interruption of a beam of radiation (e.g. light 20) by an object (50 FIG. 1) in the beam. The device includes a light emitter 12 and a light detector 32 each enclosed in a housing 10 and 30. In order to accommodate different spacings between the housings different caps 14 having varying size apertures 11 are fittable to the housings. This allows varying amounts of light to be issued and/or detected. Other ways of adjusting the amount of light passing through the cap are disclosed.

Abstract: A drill has a tubular outer housing and a tubular inner housing. The inner housing is movable between extended and retracted positions. A pneumatic motor with a chuck mounts to the inner housing. Air pressure is delivered to annular pistons to cause the inner housing to extend and retract. Also, an annular hydraulic chamber with a variable orifice bypass controls the rate of feed. A processor records the total number of holes being drilled as well as recording the time duration for each hole.

Abstract: An electric drill apparatus having a low profile is provided which comprises an annular cutter, a motor for rotating the annular cutter, a rotary shaft assembly for rotating the annular cutter attached to its leading end about a rotating, a rotation reduction mechanism disposed between the motor and rotary shaft assembly for transmitting a driving force of the motor to the annular cutter through the rotary shaft assembly, a feed mechanism responsive to an operation of a manual handle, for moving the rotary shaft assembly along with a straight line to advance or retract the annular cutter attached to the rotary shaft assembly with respect to a workpiece, and an adhesion base for securing the electric drill apparatus to the workpiece. The annular cutter has a plurality of cutting blades comprised of cemented carbide tips fixed on its lower end, thereby it is capable of rotating at a high speed.

Abstract: A woodworking machine is disclosed. The machine includes a cutting tool and a motor adapted to drive the cutting tool. The machine further includes a detection system to detect a dangerous condition between the cutting tool and a person, such as a person coming into contact with the cutting tool. A reaction system is provided to disable the cutting tool, such as by covering, blocking, destroying, wrapping, etc., upon detection by the detection system of the dangerous condition.

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: The present invention teaches a method and apparatus for making measurement of an object on a machine, such as a machine tool, using an optical measuring apparatus which includes a light source for generating a beam of light which is incident on a detector. A detection signal is generated within the detector each time the beam is interrupted. The duration and/or frequency of the detection signals are evaluated and an output signal is emitted from the detection only if a further detection signal is present within the detector in a specified time interval from the generation of an earlier detection signal.

Abstract: There is provided an apparatus and method for detecting stuck tools in automated machining operations. When a machining operation on a workpiece is finished, the tools are retracted from the workpiece. Prior to moving the workpiece to another machining operation, a stuck tool detector is moved along a plane of separation between the machine head and the workpiece. If a stuck tool is present, the detector senses the stuck tool and sends an alarm signal of the stuck tool condition so that the operator or controlling microprocessor based system is alerted to the stuck tool. Appropriate actions or repairs can then be carried out.

Abstract: An abnormality detection apparatus for a tool (11) is described for judging abnormalities of a tool by a uniformly set threshold value in relation to a cutting load even in a machining process wherein a feed rate changes every moment. The abnormalities of the tool can be judged by the uniformly set threshold value on the basis of the tool load wherefrom the feed load that fluctuates upon the feed rate has been removed.

Abstract: A method of and an apparatus for preventing accidents caused by blockage of a rotatable tool when working with a hand-held tool including the rotatable tool (8), a drive motor (7) for driving the rotatable tool (8), and means (5, 6) for interrupting transmission of a drive torque from the drive motor (7) to the rotatable tool (8) dependent on an operational condition of the hand-held tool, with the method including determining the operational condition of the hand-held tool by measuring displacement of the hand-held tool in space in at least two points of the hand-held tool spatially spaced from each other and spaced from a tool axis; subtracting two obtained displacement measurement variable (a.sub.1, a.sub.2) from each other; and thereafter, calculating an actuation signal that actuates the interrupting means (5, 6); and with the apparatus including sensors and an evaluation circuit for implementing the method.

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 machine with a worn detection function for a tool capable of reliably carrying out a worn detection for a tool. A present consumption power PW1 of a built-in motor 19, driving a main shaft 11, is watched and compared with a reference consumption power PW2, previously defined, by using a load meter 31, an A/D converter 32, a comparator 33 and a processing unit 34, thereby wear on the tool 12 is detected when the consumption power PW1 is larger than the reference consumption power PW2 as a cutting process is advanced. The main shaft 11 is supported by air static-pressure bearings 14 to 18, so that noise created with rotating, which exert an influence upon the consumption-power detected value, is extremely smaller as compared with the conventional antifriction bearing and so on. Thereby allowing delicate fluctuation of the consumption power to be detected, and naturally the worn detection for the tool 12 to be ensured.

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: A method of monitoring the condition of a tool in a machining operation for producing a plurality of toothed workpieces. The process comprises measuring the temperature of at least a portion of the plurality of workpieces each at essentially a same predetermined amount of time after machining. The temperature of each measured workpiece is compared to at least one workpiece reference temperature value indicative of a wear condition of the tool. If the measured temperature is less than or equal to the workpiece reference temperature value, machining of subsequent parts continues, or, if the measured temperature is greater than the workpiece reference temperature, the machining operation is stopped.

Abstract: A magnetic based drill assembly comprising a support platform mounted to the magnetic base for attachment to a work piece includes a feed mechanism operatively connected to the platform for rectilinear movement between a fully retracted position and a fully extended position. The feed mechanism includes a splined collar slidably mounted to the splined arbor for movement relative to the splined arbor and for rotatably supporting a drive tool. The motor is mounted in a stationary position offset and substantially parallel to the feed mechanism to reduce overall height and weight of the drill assembly. As the splined arbor is located within a cylindrical feed arbor a liquid coolant can be directly injected on the drill tool and workpiece during operation of the drill assembly. Further, an electrical feed rate monitor provides a signal to the user to indicate the optimal feed rate of the drill tool.

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: A chuck comprising a chuck body and monitoring electronics for detecting chuck faults fitted within the chuck body. A wireless transmission means is provided on the chuck body for transmitting signals from the monitoring electronics. The chuck has a dynamo having a housing fixed in the chuck body and a rotatable rotor having a mass for rotating relative to the housing when the chuck rotates due to an inertial moment of the mass to produce electric energy to power the monitoring electronics. Optionally provided is an electric energy storage means for storing energy from the dynamo and powering the monitoring electronics to provide for constant operation of the monitoring electronics.

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: The invention relates to a process and device for detecting and/or compensating for static jointing and wear errors in the fine drilling of workpieces by means of an adjusting tool (18) bearing an adjustable cutting insert (28) and capable of being clamped to a machine shaft (14). According to the invention, before a drilling or a series thereof is made, the diameter of the circle of travel of a radially outer cutting edge (44) of the cutting insert (28) is measured on the clamped adjusting tool with the machine shaft (14) rotating and evaluated within the adjusting tool (18) for adjustment purposes.

Abstract: A spindle device for detecting the completion of an automatic tool changing procedure comprising a spindle (11) having a tool holder support portion (22) formed at the forward end thereof, a drawing bolt (17) with a through-hole (18) through which an air is blown in the vicinity of a tool holder support portion (22) of the spindle (11) for cleaning in the automatic tool changing procedure, and a pressure detection means (21) disposed in association with the through-hole (18) of the drawing bolt (17), wherein whether or not a tool holder (9) is suitably mounted on the tool holder mounting portion (22) is judged on the basis of an air blow pressure detected by the pressure detection means (21).

Abstract: A tool holder comprises a receptacle having one end connectable with a machine spindle, to a receptacle and the like and an opposite end, a head provided on the opposite end and having a coaxial cylindrical head opening, a housing received non-rotatably and axially longitudinally displaceable in the head opening and having a coaxial cylindrical housing opening, a quick exchange insert for a tool insertable in the housing opening and coupleable with the housing, and an inner signal device reacting to a relative movement between the head and the inserted quick exchange insert to produce a disturbance signal which identifies a damaged or a destroyed tool.

Abstract: In a drilling control apparatus for properly controlling a load sitting on a drill, a cutting reaction force estimate unit (1) estimates a disturbance load torque Yz acting on a servomotor (feed axis) (63) based on a speed signal X1z to the servomotor (63) and a torque value U1z commanded to the servomotor (63). In drilling operations, the cutting reaction force Yz is equivalent to a cutting reaction force generated between a drill (75) and a workpiece (91). Note, rotation of the drill (75) is controlled by a spindle motor (73) and a position in a Z-axis direction of the drill (75) and a feed speed of the drill (75) are controlled by the servomotor (63) through a spindle head (74).

Abstract: A drilling method and a drilling apparatus of a hard brittle material in which a core drill is used for abrasive grinding of high accuracy and high durability.

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: A toolholder device for a machine tool comprises a holder body driven by a machine tool drive spindle, and a toolholder supported on the holder body so as to be circumferentially and axially displaceable. The holder body and the toolholder are provided with displacement detection elements which are arranged circumferentially in interdigitating relation. A support shaft extends from either member of the holder body and the toolholder toward the other member. The outer surface of the support shaft and the inner surface of a support hole of the other member to be fitted over the support shaft are formed with helical guide grooves which are opposite to each other and slopingly extends with respect to the rotational axis of the toolholder device.

Abstract: Peck drilling operations using a drilling tool with a rotatable bit are controlled according to the present invention. A control computer is used to detect various drilling conditions, such as dull or broken bits, transitions between different materials in a workpiece and a breakthrough condition. The control computer continually monitors the thrust and torque applied to the drill bit. A separate feed amp and computer having a pre-programmed feed motion routine for controlling the feeding movement of the drill bit signals the control computer when the bit is in a peck cycle. The control computer is responsive to an indication that the bit is a peck cycle for ignoring the thrust and torque readings during the peck cycle. By determining when the bit is in a peck cycle, the control computer is able to differentiate between a normal peck cycle and other drilling conditions, such as a dull or broken drill bit, transition between materials or breakthrough.