Abstract: The invention is directed to a method for manually measuring a workpiece with a manually guided coordinate measuring apparatus. The apparatus includes a carrier for a probe which, in turn, carries a probe ball 12 on a deflectable probe pin 11. The carrier is movably journalled in several spatial directions. The probe ball 12 is brought into contact with the geometric element of the workpiece 30' to be measured and is guided therealong in continuous contact therewith. Signals (.phi., .psi., z) of coordinate measuring devices are generated with the movement of the probe. Signals (u, v, w) of a transducer of the probe are generated with a deflection of the probe pin 11. Control signals (80 to 84) are generated from the first signals and/or the second signals and these control signals characterize the start and the end of the measuring operation on the geometric element and the validity of the coordinate measurement values (X, Y, Z).

Abstract: A contact type sensor for sensing an object includes a body; and a contacting member which contacts the body and a shaft. One end of the shaft is connected to the body of the sensor and another end of the shaft supports the contacting member. The shaft is rotatable within a predetermined plane, and the shaft is more flexible in a direction perpendicular to the predetermined plane than in a direction parallel to the predetermined plane.

Abstract: An interface circuit for processing signals from a touch trigger probe is adapted to prevent the generation of false trigger signals during an inspection cycle. The probe incorporates a plurality of strain gauges, the voltage across which rises above a predetermined threshold when a stylus supported by the probe contacts a surface. When the probe is moved away from the surface and the stylus loses contact, the outputs across the gauges drop below the trigger threshold. The interface prevents false triggers When, while the stylus is in contact with a surface, a machine vibration occurs which causes an oscillation in the voltage across the gauges; the voltage dropping below the threshold level (causing the interface to reset), and then immediately passing back up through the threshold, causing the interface to emit a trigger signal.

Abstract: A touch trigger probe for a coordinate measuring machine or machine tool has a stylus, which is biased into a rest position. The stylus has two independent supports, provided within a housing. A first support comprises a skirt of a stylus holder which is axially constrained on a surface of the housing. The second support comprises a kinematic arrangement of cylinders and balls, together with a planar spring, which together provide lateral constraint. The first support is biased by a much lighter force than the second support, so that its friction is very low. This reduces the lobing and hystersis of the stylus movement, and thereby increases the accuracy of the probe. The stylus movement first takes up a clearance between the first support and an abutment surface of the housing and then disengages the kinematic arrangement of the second support upon further stylus movement.

Abstract: A probe for a position determining apparatus includes a sensing space and a movable stylus supported for three-dimensional position determining movement which extends into the space. A device emits sensing radiation into the space and a collector collects the sensing radiation from the space. A deflector is supported on the stylus within the space to deflect emitted sensing radiation and is movable with position determining movement of the stylus. The deflector concentrates the sensing radiation and the collector is sensitive to variations in the intensity distribution of collected deflected radiation which occur due to the three-dimensional movement of the stylus.

Abstract: A method for improving accuracy of dimensional measurements of a touch trigger probe. The method includes moving a touch trigger probe in an approach direction toward an object, contacting a contact point on the object with a portion of the touch trigger probe, generating a trigger signal corresponding to coordinates of the contact point after the touch trigger probe travels a pretraveled distance, and adjusting the coordinates to compensate for the pretravel. The adjusting step compensates for bending of the touch trigger probe and the bending is calculated as a function of trigger force derived from contact forces of a kinematic seating arrangement of the touch trigger probe. The method is effective in compensating for variations in trigger force due to the approach direction commonly referred to as lobing. The method is applicable to straight and non-straight touch trigger probes.

Abstract: The invention is directed to a probe head of the measuring type equipped with measuring force generators (15 to 17) for the generation of measuring forces of pregiven magnitude and direction. The probe head further includes a system for arresting or clamping the displaceable part 10 of the probe head in preselectable directions. The measuring force generators are arranged directly on the displaceable parts (4, 9, 10) of the guide units for the different deflection directions (x, y, z). The arresting or clamping system is implemented in the form of an electronic control circuit which applies a signal to the force generators (15 to 17) which is opposite to the deflection of the displaceable part 10. In addition, the probe head includes a system for damping the displaceable part. This damping system operates also on an electromagnetic basis with the aid of the measuring force generators configured as plunger coils.

Abstract: A touch sensor of the invention can output a directional information from which direction an object to be measured touches a contact, as well as a positional information. The touch sensor includes a movable plate; at least four movable contacts provided on the movable plate and arranged in a rectangular shape; a measuring shaft attached to the movable plate to extend perpendicularly thereto and having a contact portion at one end thereof; a base plate situated at a side opposite to the movable contacts and having at least four fixed contacts formed at positions corresponding to the respective movable contacts so that the fixed contacts contact the corresponding movable contacts; a device for uring the movable plate to the base plate so that the movable contacts and the fixed contacts contact together; and insulating guides provided on the base plate or the movable plate to surround the movable and fixed contacts. The guides contact and guide the movable or fixed contacts.

Abstract: Mechanical energy is supplied to an implement on a rotating spindle, and a generator on the implement converts the mechanical energy into electric power. Preferably the energy is supplied in the form of rotary motion via the work spindle. Alternatively, a fluent medium, for example, coolant or compressed air, can be supplied, in which case the medium is used to drive a turbine wheel coupled to the generator.

Abstract: A multi-coordinate probe including a housing, at least one tracer pin for scanning an object and deflectable in a plurality of coordinate directions upon engagement with the object, and a support for supporting the tracer pin in the housing and formed of a plurality of multi-arm leaf springs having each at least one axially extending spring component.

Abstract: A control signal transmitting device is used for a control device, such as a position detecting device. The transmitting device includes a position detecting sensor, and a receiving device situated near the position detecting sensor. The position detecting sensor includes a sensing device, a radio wave transmitting device electrically connected to the sensing device, and a device for directing the radio wave in one direction. The radio wave transmitting device emits radio wave in a direction opposite the sensing device upon receiving a signal from the sensing device. The receiving device includes a radio wave receiving device disposed to face the radio wave transmitting device for receiving the radio wave transmitted from the transmitting device, and a shielding device for covering the receiving device to receive the radio wave from one direction.

Abstract: In a probe element for coordinate measuring systems using micro-probe elements and piezo-resonators which change their resonance characteristics upon contact, the probe element has piezo-resonators arranged in a polygonal configuration. Micro-probe elements are arranged in a polygonal configuration on the piezo-resonators and sense inner and outer surfaces in different coordinates. The tactile sensing of the micro-probe elements on the surface of the specimen is effected by measuring the change in the resonance characteristics of the piezo-resonators.

Abstract: An apparatus and method for center finding and physical proximity measurement, the apparatus including a reactance controlled signal source for producing a measurement signal having a measurement signal frequency dependent upon reactance and a probe tip connected to the signal source. The probe tip is operable to receive the measurement signal while presenting a measurement reactance to the signal source, the measurement reactance being due to coupling of the probe tip with a workpiece adjacent the probe tip and the measurement reactance varying in accordance with the physical proximity of the probe tip to the workpiece. The measurement reactance causes the signal source to vary the measurement signal frequency according to the proximity of the probe tip to the workpiece. The measurement signal frequency is sufficiently high to enable the measurement signal to be radiated by the probe tip for reception by a remote receiver.

Abstract: A multi-coordinate probe includes at least one tracer pin for scanning an object and deflectable in a plurality of coordinate directions upon engagement with the object, and a plurality of sensors for detecting deflection of the tracer pin and having their respective measuring axes intersecting at the scanning pole, defined by the tracer pin.

Abstract: An arrangement for measuring distortion in cylinders. A sensor projects straight out of the end of a motion-transmitting arm. The arm can be both translated and rotated. The sensor accommodates a probe that probes the geometry of the surface of the cylinder. The sensor has a distortion-measuring structure accommodated in the head of a surface-geometry probe and a check for axially secured and undeflected tensioning of the probe. The probe is an elongated geometry-probing pin. The structure is securely tensioned remote from the chuck in the vicinity of a structure-attachment section in the head. The structure includes at least one zone of attenuation between the chuck and the structure-attachment section and has a resilient section and a strain gauge.

Abstract: A touch probe includes a stylus module (54) and a sensing module (52) to which the stylus module is releasably securable by a magnetic coupling. The sensing module comprises a strain sensitive load cell on which the stylus module is supported, and which senses strain in the stylus on contact with a surface. The stylus module provides for overtravel of the probe; a stylus-supporting member being biased into a kinematic rest position with respect to the casing of the stylus module. The biasing force in the stylus module is chosen with regard to the length and configuration of stylus. This modular system enables automated stylus changing without the need to adjust the biasing force on the stylus-supporting member when different lengths of styli are employed.

Abstract: A touch trigger probe for a coordinate measuring machine or machine tool has a stylus (14), which is biased into a rest position. The stylus has two independent supports, provided within a housing (10). In the embodiment of FIG. 1, the first support comprises a skirt (18) of a stylus holder (12), which is axially constrained on a surface (20) of the housing (10). The second support comprises a kinematic arrangement of cylinders (34) and balls (36), together with a planar spring (30), which together provide lateral constraint. The first support is biased by a much lighter force than the second support, so that its friction is very low. This reduces the lobing and hysteresis of the stylus movement, and thereby increases the accuracy of the probe.

Abstract: The shaft position sensor is provided with a movable body fixed to a measuring shaft. A first switching apparatus operating in a first measuring position and a second switching apparatus operating in a second measuring position are incorporated in the movable body. The first switching means and the second apparatuses are arranged in parallel with the measuring shaft.

Abstract: An optical probe for measurement includes a first movable part having a stylus arranged at one end of the first movable part in a Z-direction and a sliding part movable in the Z-direction in an air bearing mechanism. A measuring device measures the Z coordinate of the first movable part.

Abstract: An arm 12 for holding a tool-setting probe 14 in a machine tool is rotatable between an operative position and an inoperative position. The operative position is defined by elements 48,52 which form a stop against further rotary motion beyond the operative position. These elements 48,52 are arranged as a kinematic support, so that the operative position is defined in a precisely repeatable manner. Springs 40 urge the elements 48,52 together. When the arm is in the operative position, these springs are stretched by a repeatable amount, so that they provide a repeatable force, in order to increase the precision of the operative position.

Abstract: A touch trigger probe incorporates piezoelectric sensors 50, whose outputs are processed by an interface circuit. The interface circuit discriminates between signals generated from the piezoelectric sensors 50 as a result of machine vibration and those generated as a result of a genuine measurement event, by the use of a timing circuit 90. The timing circuit 90 compares the time intervals (t.sub.1 -t.sub.2);(t.sub.2 -t.sub.3) between attainment of first 1.sub.1 and second 1.sub.2, and second 1.sub.2 and third 1.sub.3 output signal levels from the sensor 50, and upon the basis of this comparison validates (or rejects) measurements made with the probe. Additionally, the interface determines whether measurements made with the probe are taken upon the basis of outputs generated by the sensors 50 due to a shock wave in the stylus 24 of the probe, or as a result of strain in the stylus 24; as an alternative, measurements may be made only on the basis of strain.

Abstract: In the measurement of workpieces on a coordinate measuring machine having a work-contacting probe head of the switching type, the course over time of the contact signal is stored within a time interval which at least spans the procedural time of contact-signal development. After comparison or correlation with a prerecorded sample signal which has also been stored, the exact time of initial contact or the exact scanning coordinates are then subsequently computed.

Abstract: An apparatus for supporting and guiding a router in cutting work-pieces to form an interlocking joint comprises a base support member to which two work-pieces are mounted, at least one being in a horizontal plane. A template is also mounted to the base support member above the horizontal positioned work piece. The template is adjustably connectable to the base support member and vertical and horizontal work-piece clamping assemblies are provided with a movable clamping device so that clamping pressure is applied adjacent to each work-piece in holding the work-pieces on the base support member for cutting.

Abstract: A force control system (50) and method are provided for controlling a position contact sensor (10) so as to produce a constant controlled contact force therewith. The system (50) includes a contact position sensor (10) which has a contact probe (12) for contacting the surface of a target to be measured and an output signal (V.sub.o) for providing a position indication thereof. An actuator (30) is provided for controllably driving the contact position sensor (10) in response to an actuation control signal (I). A controller (52) receives the position indication signal (V.sub.o) and generates in response thereto the actuation control signal (I) so as to provide a substantially constant selective force (F) exerted by the contact probe (12). The actuation drive signal (I) is generated further in response to substantially linear approximation curves based on predetermined force and position data attained from the sensor (10) and the actuator (30).

Abstract: An analogue probe has a fixed structure and a stylus supporting member connected to the fixed structure by three serially mounted pairs of leaf springs interconnected by first and second intermediate members. The stylus supporting member supports an elongate stem upon which a cube, which supports three scales, is mounted. Readheads are mounted on the fixed structure, in register with the scales, to transduce movement of the stylus supporting member in three substantially orthogonal directions. The alignment of the scales about the yaw axis (extending in a direction perpendicular to the plane of the scale) determines the alignment of the measuring axes of the probe, while the straightness of the lines of the scales determines the straightness of the axes.

Abstract: An apparatus and method for accurately establishing a predetermined gap between two surfaces, and in particular, between a corona generating device and a photoreceptive member in an electrostatographic printing machine, comprising a first conductive member for being mounted on a first of the two surfaces, a second conductive member for being placed on a second of the two surfaces, the combined thickness of the first and second conductive members being substantially equal to the predetermined gap. A device is coupled between the first and second conductive members, for sensing electrical continuity therebetween.

Abstract: A sensing head for a three-dimensional sensing of a workpiece includes a housing; a lid secured to the housing at one end thereof; a transmission member axially slidably received in the housing; a transducer mounted in the housing and cooperating with the transmission member for generating a signal representing axial displacements of the transmission member; a spring disposed in the housing and urging the transmission member toward the lid; and a bearing body disposed in the housing between the lid and the transmission member. The bearing body is a spherical segment having a base and a spherical surface. The base is in contact with an inner face of the lid. A sensing pin secured to the bearing body passes through the lid. The transmission member has a circular edge constituting a seat being in a circular contact with the spherical surface and centering the bearing body in the housing.

Abstract: A touch trigger probe for a coordinate measuring machine or machine tool has a stylus (14), which is biased into a rest position. The stylus has two independent supports, provided within a housing (10). In the embodiment of FIG. 1, the first support comprises a skirt (18) of a stylus holder (12), which is axially constrained on a surface (20) of the housing (10). The second support comprises a kinematic arrangement of cylinders (34) and balls (36), together with a planar spring (30), which together provide lateral constraint. The first support is biased by a much lighter force than the second support, so that its friction is very low. This reduces the lobing and hysteresis of the stylus movement, and thereby increases the accuracy of the probe.

Abstract: A touch trigger probe includes a hybrid integrated circuit (58). On this circuit are provided both kinematic support elements (28) for supporting a deflectable stylus (14) in a precise rest position, and sensing elements (40) for detecting contact between the stylus (14) and a workpiece. Embodiments are also disclosed in which the kinematic support elements are provided on a silicon chip, e.g. by micro-machining.

Abstract: A touch probe for use on a coordinate positioning machine includes a stylus module and a sensing module securable to a movable arm of the positioning machine for releasably supporting the stylus module. The sensing module can include a sensor for detecting contact between the stylus and a surface and/or for detecting displacement of the stylus module relative to the movable arm. The stylus includes a support structure, releasably supported by the stylus module, and a stylus-supporting member for supporting the stylus, with the stylus-supporting member being biased into a rest position with respect to the support structure. The stylus-supporting member is displaceable from the rest position and relative to the support structure when a deflection force acts on the stylus, and returns to the rest position when the deflecting force is removed.

Abstract: A touch probe comprises a stylus-supporting member kinematically supported with respect to a housing at six points of contact between the stylus-supporting member and the housing. At each of these points of contact a conducting surface on the stylus-supporting member abuts a conducting surface on the housing. Each of the contacts are included in an electrical circuit. The conducting material of each of the conducting surfaces comprises a material having a resistivity of less than 8 .mu..OMEGA.cm and a melting voltage of at least 0.7 volts. A material having these properties is less susceptible to physical degradation than prior art materials used in such a probe. In a preferred embodiment the conducting material of each of the conducting surfaces is made of pure tungsten.

Abstract: A method and apparatus for measuring and sorting component parts of an assembly includes a single station wherein parts are continuously fed, precisely measured, sorted by measurement, and then transported. For measuring the parts a contact member is mounted for extremely precise and controlled movements by a voice coil motor. The contact member is initially referenced with respect to a datum and is then placed into contact with the part. An optical encoder senses the position of the contact member to enable a determination of the critical dimension. The contact member includes a removable portion that is shaped to measure a desired critical dimension. This may include the height, inside diameter, outside diameter, roundness, or location of a feature of the part.

Abstract: A method for part placement of a semiconductor chip for inspection where the semiconductor chip has a plurality of leads defining a seating plane and a body having a top. The method includes the steps of placing the body on a platform in an up position where the plurality of leads are suspended and probing the top of the body. Next measuring the position of the top of the body with reference to a predetermined coordinate system is done. Then the part is moved until the part is suspended on the plurality of leads on a reference plane. The top of the body is then probed for a second time, and the second position of the top of the body is measured with reference to the predetermined coordinate system. The thickness of the part is then determined as the distance between the top of the part and its seating plane.

Abstract: A probe comprises a support casing, a movable arm-set with an arm carrying a feeler and a detection device providing a signal further to contact occurring between the feeler and the workpiece. In order to enable the feeler to perform translation displacements along a longitudinal geometrical axis and rotations about transversal axes, the matching between the support casing and the arm-set is obtained by means of a cone-shaped surface, a spherical surface and a spring urging these surfaces into contact. An annular reference surface of the movable arm-set enters into contact with an annular plane surface of the support casing when a first eccentricity value of the feeler, with respect to the longitudinal geometrical axis, is reached, and when a second eccentricity value is reached the signal of the detection takes a determined value.

Abstract: A multi-coordinate probe is described for use in measuring machines and machine tools for measurement of workpieces. A support system is described which is configured as a multi-point bearing or support having a plurality of support points. Each support point comprises a bushing integrated into the measuring dish by way of a counter member for a ball as a support member and which is alignable with a bushing in the probe housing base. The automatic adjustment of the ball is assured by a spherical member carrying the ball and being rotatably supported in a seat or lodgment. In case of a misalignment between the bushing and the ball, a torque acting upon the spherical member causes an alignment of the ball. In the adjusted stable position, the spherical members are fixed relative to their seat or lodgment.

Abstract: A touch trigger probe for machine tools or coordinate measuring machines has three strain gauges SG1-3 which react to deflection of a stylus of the probe, causing a trigger signal to be generated in signal processing circuitry SP. To reduce power consumption, and thus to reduce thermal growth of the probe, the strain gauges are fed by constant current sources CS1-3. The sources CS1-3 are servo controlled from a reference resistance R.sub.ref and constant current source CS4, by an amplifier A4.

Abstract: A radio transmission system for a touch trigger probe for machine tools or coordinate measuring machines. In the transmitter shown in FIG. 1, a 1 kHz oscillator produces a signal which is phase modulated by an electronic switch and an inverter, when electrical contacts within the probe change state. This phase modulated signal is mixed in a mixer with an unmodulated 500 Hz reference signal, produced in a divider from the oscillator, so that there is a precise phase relationship between the two signals. The receiver shown in FIG. 2 has filters which separate out the 500 Hz reference signal and the phase modulated 1 kHz signal. A decoder phase demodulates the 1 kHz signal, using the 500 Hz signal as a reference in order to increase the reliability of the resulting signal.

Abstract: A proboscis and method of use that automatically detects whether or not a disposable tip has been properly picked up. The proboscis features a probe supported on a base movable within a driven housing, a sensing flag with multiple signalling stations being fixed to the base. These allow the sensor cooperating with the flag to be fixed to the frame of an analyzer using this proboscis, rather than to be adjustably attached, so that no adjustment is needed of the sensor's position for recalibration.

Abstract: A touch trigger probe has electrical contacts. A comparator compares the resistance of the contacts with a threshold, in order to generate a repeatable trigger signal when the contacts open. To ensure that the trigger signal can be generated reliably even if the resistance of the contacts when closed should increase, the threshold set is variable. The threshold can, for example, be set by a sample and hold circuit which tracks the resistance of the contacts when closed.

Abstract: A touch signal probe wherein a stylus installation shaft 2 and a stylus are connected by two springs 8 and 10 so as to move in a X-Y direction and a Z direction and a slat of a damper 9 is contained in a closed closure space S between the spring 8 and the spring 10, which space S is filled with a viscous liquid.

Abstract: A touch trigger probe for a coordinate measuring machine or machine tool has a stylus (14), which is biased into a rest position. The stylus has two independent supports, provided within a housing (10). In the embodiment of FIG. 1, the first support comprises a skirt (18) of a stylus holder (12) , which axially constrained on a surface (20) of the housing (10). The second support comprises a kinematic arrangement of cylinders (34) and balls (36), together with a planar spring (30), which together provide lateral constraint. The first support is biased by a much lighter force than the second support, so that its friction is very low. This reduces the lobing and hysteresis of the stylus movement, and thereby increases the accuracy of the probe.

Abstract: A touch probe comprises an ultrasonic vibrating horn having a piezoelectric element which is sandwiched between electrodes and converts an RF electrical signal into ultrasonic vibration, and a feeler to be brought into contact with an object to be measured. The horn is ultrasonically vibrating in accordance with the ultrasonic vibration of said piezoelectric element. The probe further comprises a device for inputting an RF electrical signal between said electrodes so that the RF electrical signal substantially coincides with a mechanical natural frequency of said ultrasonic vibrating horn and a touch detecting device for monitoring a current between said electrodes to detect a touch between the object to be measured and said feeler in accordance with a change in current value produced at the moment said feeler touches the object to be measured.

Abstract: A touch trigger probe for machine tools or coordinate measuring machines has three strain gauges 10A-C, which respond to deflection of a stylus of the probe when it contacts a workpiece. The signals from the strain gauges are each rectified by precision rectifiers 18A-C, and then combined at a summing junction 20. A first comparator 28 compares the combined signal with a threshold voltage V.sub.ref1, to produce a sensitive trigger signal. A second comparator 30 compares the combined signal with a higher threshold voltage V.sub.ref2, which produces a confirmation signal. This confirms that the trigger signal is caused by a genuine workpiece contact, and not caused falsely by vibration or acceleration.

Abstract: A probe for position-determining apparatus and the like has a housing (10) and in the housing a sensing space (60) and an aperture (915) to the sensing space, a stylus (40) extending out of the sensing space through the aperture, a low-friction stylus support (50;17) around the aperture, a resilient element (20;120) for constraining the stylus on to the support and generally towards a neutral axis while permitting position-determining displacement on the support against the constraining element, which is outside the sensing space, while in the sensing space is a sensing arrangement (30, 42; 30, 42, 35, 37) separate from the constraining element to sense directly significant movement of the stylus from the neutral axis without contact with the stylus and to indicate such significant movement of the stylus as a position-determining displacement.

Abstract: A probe used for programming a robot arm in order to perform a cutting operation on a work-piece. During the programming operation, the probe is attached to the robot arm and moved around the profile of a test-piece. An electric lamp is provided for indicating contact between the probe and the test piece. Additional circuitry including an electric lamp is provided for indicating when the body of the probe and a pin (4) having an end tip (8) which actually forms the contracting portion of the probe are misaligned.

Abstract: A probe for use on a coordinate positioning machine has a stylus supporting assembly (15), which supports a stylus (14) for three dimensional movement relative to the probe housing (10). The stylus supporting assembly (15) comprises a first member (16) mounted on the housing (10) and having a first plane surface (18). A second member (20) has a second plane surface (22) which is retained against the first plane surface (18) by magnets (24). The second member (20) may move in all directions in the XY plane relative to the first member (16) on an air bearing (26), and rotation of the second member (20) relative to the first member (16) is prevented by a spring bellows (30). The stylus (14) is fixedly connected to a third member (42) having plane surfaces (52A,B), which are retained against corresponding surfaces (50A,B) provided on the second member (20) by magnets (56), and for movement relative to the second member (20) in the Z direction on air bearings (48).

Abstract: A touch probe comprises a stylus carrier which, in use, supports a workpiece-contacting stylus. The stylus carrier is urged into a kinematic rest position with respect to the housing of the probe by a spring which acts between a movable clamping shuttle and the stylus carrier. The clamping shuttle is movable within a bore and is engageable by an adjusting screw to adjust displacement of the clamping shuttle within the bore, and thus the degree of compression of the spring and the biasing force on the stylus carrier.

Abstract: A stylus counterbalancing mechanism for a probe includes a stylus support member suspended on a resilient suspension system and connected to a spring which provides a force to counterbalance the weight of the stylus. The spring is connected to one end of a plate which is capable of sliding up and down a rod but is locked in position due to the clockwise moment produced by the spring force. The plate is unlocked from its position, when required, by movement of an actuating member. The actuating member is slidable up and down the rod and has bearing areas arranged to provide an anti-clockwise moment to the plate to unlock it and to move it along the rod to increase or decrease the spring force as required.In the probe, the actuating member includes a projection extending through the probe housing to be operable from the outside either manually or by the co-ordinate positioning machine, the machine being programmed to move the probe to engage the projection with a fixed ledge on the machine.

Abstract: A touch probe (10) has a housing (12) and stylus-supporting member (14) biased into a kinematic rest position relative to the housing (12) by a biasing mechanism. The biasing mechanism includes a first helical spring (40) which acts between a movable shuttle (44) and an intermediate member (48). The shuttle (44) is movable within a bore (46) and the position of the shuttle within the bore may be adjusted by the action of an adjusting screw (74). A second helical spring (42) acts between intermediate member (48) and the supporting member (14). The first spring (40) has a low spring rate and is pre-loaded such that the second spring (42), which has a high spring rate, will deflect first upon movement of the shuttle (44) or supporting member (14). Once the pre-load of spring (40) has been overcome the two springs (40,42) co-operate to act as a single spring whose spring rate is the sum of the reciprocals of the spring rates of springs (40,42).

Abstract: A displacement-measuring apparatus including a cylindrical housing, a static-pressure bearing located within the housing, a probe shaft supported by the bearing so that the bearing is supported in non-contact fashion and is movable in the axial direction, and a stylus connected to the end of the probe shaft so as to apply pressure to an object. Part of the static-pressure bearing includes a hollow cylindrical bush and at least two restriction holes formed in the bush and equidistantly spaced along the circumference of the bush. These holes supply air into the gap between the probe shaft and the bush. The static-pressure bearing further includes a first set of grooves formed in the inner surface of the bush that extend along the axis of the bush so that each opposes at least one restriction hole, and a second set of grooves formed in the circumferential surface of the probe shaft that extend along the axis of the probe shaft.