Abstract: A capacitance sensing probe is disclosed for taking measurements of features on a workpiece surface. The probe has two electrodes (E.sub.1, E.sub.2) spaced apart in the direction of movement of the probe with the electrodes being disposed in an attitude normal to the surface. Only the edge of the electrodes are exposed to the surface and an electric circuit (EC) is provided for determining the effect of the surface on the fringe field capacitance between the electrodes. Guard electrodes are used to reduce the stray capacitance being measured. Various embodiments are shown with different numbers and arrangements of electrodes.

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 rotable object table which has a stator (112) a rotor (114), and positioning servo and measuring system (16). The system (16) is calibrated using an angular interferometer and an intermediate table having stator 122 and rotor 124. Values of angular displacement of stator 124 are determined by the interferometer by solving 3 orthogonal simultaneous equations derived from the equation R+R.sub.o =K sin (.THETA.-.THETA..sub.o), and are compared with corresponding angular displacement as determined by the system (16).

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 modular multi-fixturing system for a machine tool comprises an elongate core (22) for mounting on a rotary axis of the machine with its longitudinal axis aligned with the rotary axis, and a plurality of workpiece-providing cassettes (24) mounted on the periphery of the core. The core has three flat surfaces on its periphery onto which the cassettes are clamped by fixed and moveable clamping plates (36, 34) which extend along the whole length of the core. The clamping plates define with the flat surfaces axial vee grooves with which corresponding vee surfaces on the cassettes can be engaged by axial movement of the cassettes. The cassettes may carry workpieces and be re-used or may themselves constitute workpieces and be sacrificial.

Abstract: The 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 shank (10) for retaining a tool or touch probe in the socket (S) of a machine tool spindle comprises 6 areas of surface which, in use, bear against the wall of the socket (S). The areas of surface are provided by three balls (34) resiliently supported for movement radial to a shank axis (A) on small flange section (26) (FIG. 2 ) at one end of the shank (10), and three further balls (36) embedded in the other end of the shank (10). As the shank is drawn into the socket (S) the small flange sections (26) deform allowing the balls (34) to move radially inward until the surface of balls (36) engage the wall of the socket (S). A pull-up stud (38), supported on a frusto-conical block (40) is connected to the shank by a plunger (42) and compression spring (46). Retraction of the shank into the socket by pull-up stud (38) against the resilience of the small flange sections (26), causes the plunger ( 42) to compress spring (46) until the block (40) bears firmly against the wall of the socket (S).

Abstract: A sample (14) is illuminated by light from a laser source (16), which is reflected to it by a dichroic filter (18) and passed through a microscope objective (20). The microscope objective (20) focusses a two dimensional image of the illuminated area onto a detector (22). On the way to the detector (22), the light passes through an interference filter (26), which selects a desired line from the Raman spectrum scattered by the sample (14). The filter (26) can be tuned to any desired Raman line by rotating it through various angles of incidence (.THETA.), about an axis (28) perpendicular to the optical axis.

Abstract: A method of scanning a workpiece surface is disclosed in which a machine carrying a scanning head is moved along a path, preferably at constant velocity, while a surface contacting device is moved by the scanning head to oscillate transversely to the instantaneous path direction to scan an area of the surface. Transducers on the machine, the head, and where necessary the surface contacting device provide data relating to the positions of the surface contacting device to data gathering device under the control of a computer. Apparatus for carrying out the method is also disclosed and includes a scanning head for moving the surface detecting device which may be a stylus or a probe relative to one axis, and preferably orthogonal axes. The head can include a set-up for inertia balancing the head and mass balancing the surface detection device. Also the head may include air bearings on which the stylus or probe are supported for oscillation.

Abstract: An opto-electronic scale reading apparatus comprises a light source (20) which projects light via an index grating (22) onto a reflective scale (10). Light is reflected from the scale (10), passes through an auxiliary grating (36) and is incident upon an analyser grating (28), at which a plurality of periodic light patterns are formed. Light from the light source (20) travels initially parallel to the scale plane, and is subsequently deflected through 90.degree. by a beam splitter cube (26); the light is thus incident upon and reflected and off the scale (10) at 90.degree. to the scale plane. This arrangement enables large movements of the readhead in a direction perpendicular to the scale.

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 thereof 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 surface (12A) during a scanning operation.

Abstract: Probes (18A,18B,18C) can be interchangably 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 (26) is transmitted to a receiver module 28. Such an arrangement requires a battery in the probe. To conserve battery power, the probe is normally in a stand-by mode, but can be switched on by an optical signal transmitted from the module 28 to a receiving photodiode 32 on the probe. This switch-on signal is modulated at a different frequency for each probe. Each probe contains a filter for the signal received by the photodiode 32, responsive only to the frequency of modulation of its own switch-on signal. Probes which are not intended to be switched on therefore do not react to the switch-on signal of another probe, thus conserving battery power further.

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 measuring system for measuring the position of an object comprises a laser (10), a laser interferometer (16), and a detector (24). A series of sensors for sensing environmental conditions are provided; the sensors may be attached to the object. The sensors transmit information back to a central control (46) via LED transmitter (54). The transmitter (54) is powered from a battery (56) which is in turn charged by transducing (with a solar cell) part of the power of the light beam (12) generated by the laser (10). The sensors may be temperature sensors, pressure sensors, humidity sensors, refractive index sensors, vibration sensors, or beam alignment sensors.

Abstract: A device to assist in setting up the pitch, roll, yaw and standoff of a read head relative to a scale, so as to improve the quadrature relationship of its outputs. Two superimposed Lissajous figures are produced on an oscilloscope screen. One of these figures is a rotation or reflection of the other. The read head is adjusted until the Lissajous figures coincide. Simpler, less accurate arrangements are also described, in which a variable DC output signal is produced which represents the radius of a hypothetical Lissajous derivable from the signals. The read head is then adjusted to give a constant DC output, representing a constant Lissajous radius.

Abstract: Disclosed is a method of obtaining data to determine a rotation matrix R, for rotating the axes (x,y,z) of an analogue probe coordinate system (PCS) onto the axes (X,Y,Z) of a machine coordinate system (MCS). The head (14) of the machine is driven to bring a measuring tip (16) of a stylus (12) supported by the probe for movement relative to the head (14) into engagement with a kinematic location (20). With the tip (16) fixed in the location (20) the head is then moved to six different locations. The coordinate positions of the head (14) in the machine coordinate system (MCS), and the stylus (12) in the probe coordinate system are used to set up six simultaneous equations and thus determine the rotation matrix R.

Abstract: A device for changing styli or probes in a coordinate measuring machine has a magazine (330) with several stations each holding a stylus or probe (320). A holder (310) on the quill of the coordinate measuring machine has an opening (313A), so that kinematic support elements (325) in the holder (310) can be moved underneath cooperating kinematic support elements (324) on the stylus (320). When the holder (310) is engaged in the magazine (330), an extension plate (334) causes the arm (314) to swing out of the way. This arrangement enables the holder (310) to pick up the stylus (320) purely by translational movements of the holder (310), without the need for any separate motor or electromagnet to couple the stylus to the holder.

Abstract: A measuring probe includes a fixed housing (2) and a movable stylus carrier (10) which is urged by a spring (18) into a rest position in a support (14). The support comprises six seating elements confronting corresponding seating elements (12) on the stylus carrier. Strain gauges (20) are provided on the seating elements of the supports (14) to measure the strain produced in the supports (14) by the movable member resting on them. Each strain gauge produces a signal from which any variation in strain, and hence any displacement of the movable member relative to the fixed member due to a change in forces between the two, can be determined by a computer.

Abstract: A manually operable probe head (10) has a support (12), by which the probe head may be attached to the head of a coordinate measuring machine, a first rotor (14) rotatable about an axis (16) relative to the support (12), and a second rotor (46) rotatable relative to the first rotor about a perpendicular axis (48). The first rotor (14) and second rotor (46) are each rotatable through a plurality of kinematic rest positions, into which they may be axially urged through retraction of a tie bar (90). Location of the first and second rotors when not in their rest positions is achieved by three spring loaded pistons (34) and (72). The pistons (34) and (72) ensure that even when not in their rest positions, the first and second rotors always come to rest adjacent such a position. The second rotor (46) carries a connector (54) for receiving a touch probe (50).