Abstract: A measurement probe for use on machine tools or coordinate measuring machines has a stylus (12) mounted in a probe body (10), for displacement in each of the axes x,y,z. On each axis, the relative motion is supported by a pair of cylindrical linear bearings, which are parallel to each other and spaced apart. The bearings comprise a shaft (30) and concentric sleeve (26), between which is located a cage (28) of ball bearings. The arrangement achieves good performance in a relatively small housing.

Abstract: An optical metrological scale produced by a rolling method, to give a profiled upper scale surface which is imparted by an embossing roller. To prevent uneven strains, which could affect the pitch of the scale, the support roller has a similar embossing profile, so that the lower side of the scale is also given a profiled surface. The embossing roller is freely rotatable, while the support roller is driven.

Abstract: A mounting comprises a base supporting a first rotary motor whose shaft has secured thereto a housing supporting a second rotary motor whose shaft has the stylus secured thereto. Each motor is operable optionally in a constant torque mode and a positioning mode and each motor has an angular position transducer. In use, the base is secured to the operating member of a coordinate measuring machine and the machine is driven through a path such that the free end of the stylus can maintain engagement with the surface of a workpiece under the force generated by one of the motors while that motor is in the constant torque mode. The profile of said surface is then determined as a function of the coordinate position of the operating member, the angular position and the length of the stylus.

Abstract: A probe head for orientating a probe relative to a head of a coordinate measuring machine, has a support a rotor rotatable relative to the support, and a swivel rotatable relative to the rotor. The rotor and swivel are mounted for rotation through a series of discrete, and repeatable rest positions. The relative orientation of support, rotor and swivel is detected by an indicating mechanism comprising a printed circuit board having a series of electrical conductive elements and a contact arm mounted for rotation over the conductive elements on the circuit board. When the electrical contacts of the contact arm come into register with the conductive elements on the circuit board a pulse is transmitted to a micro-processor which determines the relative orientation of e.g. the support and rotor which is shown on the LCD.

Abstract: A contact-sensing probe for use in co-ordinate measuring machines has a housing (10) intended to be supported by the machine and a plate (11) supporting a stylus (12) intended to engage a workpiece (15) to be measured. The plate (11) is connected to the housing (10) by a first set of three wires (14A) extending obliquely upward from the plate (11) and a second set of three wires (14B) extending obliquely downwards from the plate (11). The wires (14A, 14B), which are flexible, are placed into tension by torque applied to the plate (11) by a torsion spring (18). This establishes a rest position for the stylus (12). Displacement of the stylus (12) from the rest position, due to engagement with the workpiece (15), is accommodated by buckling of the wires (14A and/or 14B). The stylus (12) is displaceable in the sense of being tilted in any plane containing the axis (10A) of the housing (10 ), and the arrangement of wires (11) enables displacement in either sense of the direction of the axis (10A).

Abstract: A tape scale applicator (100) has a guiding channel (142) for aligning a metrological scale (126) relative to a substrate (150) to which the scale is applied. The applicator (100) is attached to a mounting bracket (153) for a read head (used to read the scale) provided on a member (154), which moves relative to the substrate (150). The applicator (100) is used to apply the scale (126) to the substrate in order to ensure that the scale (126) has a precise alignment with the read head, once the read head is connected to the mounting bracket (153). The tape scale (126) has a backing strip (140) which is removed via a second channel (170) as the scale (126) passes through the guiding channel (142).

Abstract: Apparatus for generating a quadrature signal for the purpose of determining the direction in which the scale is being read. There is provided a primary grating means defining spaced lines and adapted for generating orders of diffraction, secondary grating means defining spaced lines arranged at an angle to those of the primary grating means thereby to separate said orders of diffraction into differing phases, and tertiary grating means movable together with the secondary grating means relative to said primary grating means and adapted for detecting the respective said phases and for generating correspondingly phased light modulations which are detected by respective transducers connected to a quadrature-forming circuit.

Abstract: Disclosed is a three dimensional coordinate measuring machine which is used to measure a workpiece. The machine has a probe containing a piezoelectric crystal which is capable of detecting the shockwave generated when the probe stylus contacts the surface of the workpiece, in order to provide a trigger signal. In order to reduce the risk of the piezoelectric crystal not triggering satisfactorily upon receipt of this shockwave, the workpiece is vibrated so that immediately upon contact the vibrations travel up the probe stylus to trigger the piezoelectric crystal. The vibrations are introduced by a vibration transducer which is bolted to the bed of the coordinate measuring machine.

Abstract: Probes (18A, 18B, 18C) can be interchangeably mounted in the spindle (12) of a machine tool. Each probe has an optical signal transmission system, in which an optical signal from a light emitting diode (24) is transmitted to a receiving photodiode (26). To prevent interference between the different probe signals, each probe modulates the emitted light at a different carrier frequency. The receiver (28) contains electronic bandpass filters to separate out the different carrier frequencies. The signal information is encoded onto the optical signal by phase modulation of the carrier frequency.

Abstract: A laser inteferometer system is disclosed which is able to make measurements of any deviations in the movement of a machine component which is moving along a main movement axis. The system can measure roll, pitch, yaw, straightness, and parallelism of two tracks using a single laser beam. FIG. 1 shows an arrangement for measuring roll of a vertical machine column (2) during movement of the column along the x-axis of a machine. A straight mirror (6) is positioned on the machine bed with its longitudinal axis aligned with the x-axis, and its reflecting surface normal to the x-axis. An optical component including a polarizing beam splitter is mounted for movement with the machine column and generates from a laser beam (A), a measuring beam (B1) and a reference beam (B2) both directed at the mirror, but laterally separated in the direction of the Z axis. The reflected beams from the mirror are re-combined in the optical device to form a return beam (C) directed towwards a detector adjacent the laser (9).

Abstract: A probe for use in co-ordinate measuring comprises three orthogonal spring parallelograms, each with a respective scale and read head, for measuring the location of a workpiece-contacting stylus. The probe also has a trigger sensor in the form of a piezoelectric crystal, which gives a trigger signal at the instant the stylus contacts the workpiece. This enables the scale readings to be taken at the instant of contact, in order to reduce dynamic errors.

Abstract: The disclosure pertains to a probe head (PH) for use in coordinate measuring machines and having a stylus (10) supported for axial displacement (D1) and angular displacements (D2,D3). A transducer (T1) senses axial forces (F1) on the sensing end (11) of the stylus due to engagement therefore with a workpiece 12. A strain gauge system (16) provided on the stylus senses transverse forces (F2) on the sensing end (11) of the stylus. The forces (F1,F2) are used to determine the orientation of the surface (12A) of the workpiece and a control system is described which responds to those forces to maintain the stylus normal to said surfce (12A) during a scanning operation.

Abstract: A mechanism for clamping a tool (e.g. a probe) and a shank together comprises a clamping pin (144), which bears against an annular lip (142) in the rear face of the probe. A shaft (148) of the pin (144) extends into the shank (150), and two diametrically opposite, radially extending clamping bolts (160) supported by the shank (150), bears against a frusto-conical clamping surface (158). The action of the bolts (160) on the surfaces (158) urges the probe and shank together. The probe and shank are adjusted laterally relative to each other by four adjusting bolts (166) supported in the annular lip (142) which bear against a flange (152). The flange (152) is provided on the shank (150) and extends into the probe (140).

Abstract: A scale for use with scale reading apparatus having grooves spaced along its length at a pitch P. Each groove is made with a shape or depth variation along its length to provide a scatter mechanism for breaking up the ordered diffraction pattern which would otherwise be generated by the grating structure defined by the grooves. Methods of making the scale involve applying a transverse vibration to the cutting tool during the groove cutting operation.

Abstract: A hinge probe is described (see FIG. 1) in which a plurality of plates (4,10,45,46,47) are stacked in the direction of the probe axis (11). The plates are connected together in pairs by hinge means (12,50,52 and 53), various forms of which are described, which define pivot axes and which constrain each pair of plates for relative pivoting movement about a side edge of the pair. The pivot axes are arranged to be mutually orthogonal to enable tilting of a stylus (2), attached to one of the plates (4), in any direction by pivoting of one or more of the plates when a force is applied to the stylus. An axial rest position for each movable plate on an adjacent plate is defined in combination with the hinge by a further support (14,16) disposed between each pair of plates on the opposite side of the probe axis (11) to the respective pivot axis. A spring (17) urges the plates into their respective rest positions.

Abstract: The linear drive motor is based around a proportional solenoid L1, to which is connected a velocity transducer F1. The velocity output of the transducer F1 is compared to a reference voltage V1 by an error amplifier/driver A1, which in turn drives the solenoid L1. This gives velocity control to the linear motor, without the usual disadvantageous rotary to linear conversion mechanisms. The linear motor therefore has a higher bandwidth, and is free from mechanical vibrations and resonances, and from backlash.

Abstract: The invention relates to a straightness interferometer system, for measuring transverse deviations in the relative movement of machine parts. The preferred embodiment comprises a laser (30) which directs a single frequency laser beam, polarized in two orthogonal modes, along a principal axis P onto a beam splitter (24) which splits the beam into its two modes to provide two secondary beams (26,28). One of the secondary beams (26) is undeviated from the principal axis, the other (28) is deviated through a small angle. A roof-top reflector-prism combination (30/40) is positioned in the paths of both secondary beams in a plane normal to the principal axis, the prism being arranged to deflect the deviated beam into a direction parallel to the principal axis so that both beams are reflected back to the beam splitter where they re-combine to form a combined beam.

Abstract: A coordinate measuring machine has X and Y component drives for a probe. The two drives are driven to produce a resultant motion describing a curve having a given start velocity vector, a given end velocity vector, and following a given velocity function V=f(K,t) wherein K=a maximum acceleration term and t=time. A computer is programmed to determine the X and Y components (V1X,V1Y) of the start velocity vector and the X and Y components (V2X,V2Y) of the end velocity vector. Thereafter the program determines the difference (DVX) between the X component (V1X) of the start velocity vector and the X component of the end velocity vector, and computes values of the function V=f(K,t) for that difference (DVX). Proportionate values are computed for the difference (DVY) of the respective Y components (V1Y,V2Y) of the start and end velocity vectors. The values are output to the respective X and Y component drives of the machine to drive the probe through the resulting curved path.

Abstract: A co-ordinate measuring machine has a probe (62) used to touch points on an article (61) under manual control by a user, e.g. from a joystick (69). A computer (71) determines a vector describing the direction of probe movement prior to touching each point. On the basis of the number of points touched by the user and their respective vectors, the computer makes a decision as to the shape of a feature of the article under inspection, e.g. whether it is a flange, slot, boss, bore, internal sphere, external sphere, cylinder or cone. It can then either calculate a relevant geometrical parameter such as a dimension of the feature, or write a part program for future inspection of the feature on further, nominally identical articles (61). This can be done automatically without the need for the user to tell the computer anything about the shape of the feature concerned.

Abstract: For laser interferometer systems used for taking measurements on a machine, optical devices such as interferometers, reflectors and beam splitters are required to be mounted on the machine spindle or the machine bed. It is an advantage for some of the optical devices to be interchangeably mountable on the spindle or the bed to avoid duplication. The invention proposes that for interchangeability, a bed-mounted retro-reflector having the geometric center of its optical component positioned at a distance (b) from the side in contact with the machine bed, and (b-x) from the opposite side, while a spindle mounted interferometer has the geometric center of its optical component positioned at a distance (b-x) from the side confronting the bed (which is at a distance (x) from the bed) and at a distance (b) from the opposite side. Thus the geometric centers of the optical components are each at a distance (b) from the bed.