Abstract: There is disclosed: a measurement scale suitable for use with scale reader for determining displacement; various tracks all for holding the scale and all having a channel into which the scale is magnetically attracted; and a scale tensioner which in use tensions the scale in situ by release of a preload, prior to the scale being secured to a substrate, the tensioner being removable thereafter.

Abstract: There is disclosed: a measurement scale suitable for use with scale reader for determining displacement; various tracks all for holding the scale and all having a channel into which the scale is magnetically attracted; and a scale tensioner which in use tensions the scale in situ by release of a preload, prior to the scale being secured to a substrate, the tensioner being removable thereafter.

Abstract: A tiltable table 10 is shown having (in this embodiment) two tilt positions to which top 20 and base 30 are repeatably repositionable. Support parts 32, 34, 36 and 38 provide a kinematic support in both of the two positions. Further embodiments provide more than two tilt positions. Positions are held by magnetic attraction, here, magnets, 40 and 42.

Abstract: Apparatus which can be used to calibrate, or provide measurement data on, a machine. The apparatus comprises two structures each with three spherical supports spaced in a triangular array thereon. The supports may be balls or sockets. The structures are interconnected by six members and each support has the ends of two members connected to it. The members are passive extensible measuring bars and the structures are respectively connected to fixed and movable parts of a machine so that movement of the machine parts causes relative movement between the structures and varies the lengths of the measuring bars. From measurements of the lengths of the measuring bars the actual movement of the machine part can be determined. Calibration of the spherical supports is carried out using a measuring bar which is pre-calibrated in a Zerodur jig.

Abstract: Apparatus which can be used to calibrate, or provide measurement data on, a machine. The apparatus comprises two structures each with three spherical supports spaced in a triangular array thereon. The supports may be balls or sockets. The structures are interconnected by six members and each support has the ends of two members connected to it. The members are passive extensible measuring bars and the structures are respectively connected to fixed and movable parts of a machine so that movement of the machine parts causes relative movement between the structures and varies the lengths of the measuring bars. From measurements of the lengths of the measuring bars the actual movement of the machine part can be determined. Calibration of the spherical supports is carried out using a measuring bar which is pre-calibrated in a Zerodur jig.

Abstract: An articulating probe head includes motors 12 and 18 for driving respective output shafts 14 and 20 about respective orthogonal axes z and x to move a stylus 22 over the surface of a workpiece under the control of a controller 26. At least one of the motors is inertia balanced by mounting the stator 32 of the motor on bearings 42 to allow it to rotate in opposition to the rotation of the rotor 34. Control of the speed of the spinning stator is achieved by connecting it to the winding assembly 46 of an additional “back-to-earth” motor 47 the magnet assembly 48 of which is connected to the housing. The motor 47 acts as a brake to prevent overspeeding of the rotatable stator, and can have power supplied to it to ensure that the stator does not slow down excessively when the main motor is running at constant angular velocity. Control of the power supply to the motors is achieved by the controller 26.

Abstract: A method of calibrating a scanning system comprising a machine and a measuring probe, includes the steps of error mapping the system statically and qualifying the stylus tip so that the system will provide accurate measurements, determining the positions of a number of datum points on the surface of an artefact with the probe stylus in contact with the workpiece and at zero deflection normal to the surface, scanning the surface through the datum points at a nominal stylus deflection and at the maximum speed which provides repeatable position measurements to make a second determination of the positions of the datum points, determining the errors attributable to the scanning process by subtracting the positions obtained in the first and second determinations, and storing the error values for correction of subsequent measurements of similar artefacts.

Abstract: A probe arm comprises a base member 10 securable to a surface of a machine tool, and a rotatable hub 12, carrying an arm member 16 with a tool-setting probe (18 FIG. 1). The hub has a portion 22 with three radial projections (26 FIG. 2) which rotates within an aperture 24 of the base which also has three inward radial projections 30. Together these projections form stops at the operative and non-operative positions of the probe. The aperture also has three axial raised areas 42 on an annular ledge 40 which support an annular should 44 on the hub. Thus there are six points of contact between the hub and base member in the operative and non-operative positions. A biasing arrangement comprises a detent plate 46 secured to the aperture and a planar spring 48 secured to the hub by its central region. Ball bearings 56 are loosely retained in two opposite lugs (54 FIG. 6) on the spring and run around the detent plate between two pairs of detent holes (58 FIG. 5).

Abstract: Apparatus which can be used to calibrate, or provide measurement data on, a machine. The apparatus comprises two structures each with three spherical supports spaced in a triangular array thereon. The supports may be balls or sockets. The structures are interconnected by six members and each support has the ends of two members connected to it. The members are passive extensible measuring bars and the structures are respectively connected to fixed and movable parts of a machine so that movement of the machine parts causes relative movement between the structures and varies the lengths of the measuring bars. From measurements of the lengths of the measuring bars the actual movement of the machine part can be determined. Calibration of the spherical supports is carried out using a measuring bar which is pre-calibrated in a Zerodur jig.

Abstract: Described is a device which enables toolsetting on a machine tool. The device includes a light emitting unit (10) and a light detecting unit (14). A light source (30) causes a light beam (12) to propagate from the emitting unit (10) to the detecting unit (14). A light detector (40) detects the presence or absence of the beam. A trigger signal is produced when occlusion occurs and so the position of an object can be determined by reference to the machine's coordinate readings. The beam (12) may be uncollimated and thus provide a device with an easier set-up and a greater resistance to vibration in use. The light detector (40) and/or light source may be protected from contamination by windows (34,44) or a protector having an aperture therein. The light emitting and detecting units each have an aperture for the light beam.

Abstract: There is disclosed: a measurement scale suitable for use with scale reader for determining displacement; various tracks all for holding the scale and all having a channel into which the scale is magnetically attracted; and a scale tensioner which in use tensions the scale in situ by release of a preload, prior to the scale being secured to a substrate, the tensioner being removable thereafter.

Abstract: A method of calibrating a scanning system comprising a machine and a measuring probe, includes the steps of error mapping the system statically and qualifying the stylus tip so that the system will provide accurate measurements, determining the positions of a number of datum points on the surface of an artefact with the probe stylus in contact with the workpiece and at zero deflection normal to the surface, scanning the surface through the datum points at a nominal stylus deflection and at the maximum speed which provides repeatable position measurements to make a second determination of the positions of the datum points, determining the errors attributable to the scanning process by subtracting the positions obtained in the first and second determinations, and storing the error values for correction of subsequent measurements of similar artefacts.

Abstract: A measuring probe includes a suspension module 112 in which a stylus holder 140 is suspended from a housing on a pair of diaphragms 142,144. At least one of the diaphragms is formed with spiral cut-outs whereby the stylus, which is connected at the center of the diaphragms, is able to move transversely of the axis of the housing as the stylus holder pivots when transverse forces are applied to the stylus tip. A transducer module 110 is releasably supported on the suspension module by a kinematic mounting 116,118 and is retained in position by magnets 120. The transducer module contains optical transducers 200,210,220 for measuring the deflection of the stylus.

Abstract: An articulating probe head includes motors 12 and 18 for driving respective output shafts 14 and 20 about respective orthogonal axes z and x to move a stylus 22 over the surface of a workpiece under the control of a controller 26. At least one of the motors is inertia balanced by mounting the stator 32 of the motor on bearings 42 to allow it to rotate in opposition to the rotation of the rotor 34. Control of the speed of the spinning stator is achieved by connecting it to the winding assembly 46 of an additional “back-to-earth” motor 47, the magnet assembly 48 of which is connected to the housing. The motor 47 acts as a brake to prevent overspeeding of the rotatable stator, and can have power supplied to it to ensure that the stator does not slow down excessively when the main motor is running at constant angular velocity. Control of the power supply to the motors is achieved by the controller 26.

Abstract: A tiltable table 10 is shown having (in this embodiment) two tilt positions to which top 20, and base 30 are repeatably repositionable. Support parts 32, 34, 36 and 38 provide a kinematic support in both of the two positions. Further embodiments provide more than two tilt positions. Positions are held by means of magnetic attraction, here, magnets, 40 and 42.

Abstract: The component parts of an optical measuring system include two housings (20,22) each of which contains optical elements of the system, and a base (10). The two housings are each provided on at least one face with the complementary parts of a kinematic support (18), and the optical components are arranged within the respective housings so that when the kinematic support is engaged the optical components are properly aligned. The base is provided with a kinematic support (16) on its surface which is arranged so that when the base is aligned with a machine axis, any housing placed on the kinematic support will automatically be aligned with the machine axis. Thus by aligning the base with a machine axis, the optical components of the system will automatically be aligned when the housings are connected to the base and to each other using the kinematic supports.

Abstract: A method of calibrating a scanning system comprising a machine and a measuring probe, includes the steps of error mapping the system statically and qualifying the stylus tip so that the system will provide accurate measurements, determining the positions of a number of datum points on the surface of an artefact with the probe stylus in contact with the workpiece and at zero deflection normal to the surface, scanning the surface through the datum points at a nominal stylus deflection and at the maximum speed which provides repeatable position measurements to make a second determination of the positions of the datum points, determining the errors attributable to the scanning process by subtracting the positions obtained in the first and second determinations, and storing the error values for correction of subsequent measurements of similar artefacts.

Abstract: A measuring probe includes a suspension module 112 in which a stylus holder 140 is suspended from a housing on a pair of diaphragms 142, 144. At least one of the diaphragms is formed with spiral cut-outs whereby the stylus, which is connected at the centre of the diaphragms, is able to move transversely of the axis of the housing as the stylus holder pivots when transverse forces are applied to the stylus tip. A transducer module 110 is releasably supported on the suspension module by a kinematic mounting 116, 118 and is retained in position by magnets 120. The transducer module contains optical transducers 200, 210, 220 for measuring the deflection of the stylus.

Abstract: A coordinate positioning machine has an operating module such as a tool or probe (10) mounted for translational motion relative to a table (16) with three degrees of freedom by means of three articulated linkages (18). Each of the linkages is made up of a torsion box (22) which is pivotally mounted to a vertical pillar (20) with one degree of freedom, and a pair of struts (26), each of which is pivotally mounted with two degrees of freedom to the torsion box at one end, and to the operating module at the other. The linkages cooperate to prevent all rotational motion of the operating module, while allowing translation. Motion of the operating module is actuated manually, and the mass thereof is counterbalanced by an articulated counterbalance arm which guides a cable that is in turn connected to a fusee. Displacement of the operating module is measured using scale and readhead encoders.

Abstract: A coordinate positioning machine has an operating module such as a tool or probe (10) mounted for translational motion relative to a table (16) with three degrees of freedom by means of three articulated linkages (18). Each of the linkages is made up of a torsion box (22) which is pivotally mounted to a vertical pillar (20) with one degree of freedom, and a pair of struts (26), each of which is pivotally mounted with two degrees of freedom to the torsion box at one end, and to the operating module at the other. The linkages cooperate to prevent all rotational motion of the operating module, while allowing translation. Motion of the operating module is actuated manually, and the mass thereof is counterbalanced by an articulated counterbalance arm 90 which guides a cable 96 that is in turn connected to a fusee. Displacement of the operating module is measured using scale and readhead encoders (40,50).