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 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 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 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: A scale is fixed to one part of a position determining apparatus, and a read head is relatively movable on the other part of the apparatus. Incremental scale marks are regularly spaced along the scale and are counted in a counter to give an indication of relative position of the scale and read head. The marks may for example be recorded magnetically. Some scales are distinguishable from the other, e.g., by having different amplitudes. Positioning information can then be encoded in a binary word. This can either be absolute position values, or error correction information.

Abstract: A succession of nominally identical workpieces is measured using a probe on a coordinate measuring machine. To enable most of the workpieces to be probed at a fast speed (step 40), and compensate for the errors thereby introduced, one workpiece is also probed at a slow speed (step 32). For that workpiece, a series of error values is calculated (step 36) from the differences between the fast and slow measurements. The subsequent fast measurements on succeeding workpieces are corrected by making use of these error values (step 42).

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). The holder (310) is then lifted up to engage the kinematic support elements, and the stylus can then be carried horizontally out of the magazine (30). During this operation, the kinematic support elements are biased into engagement initially by a leaf spring (335), and subsequently by a spring-loaded arm (314) in the holder (310), which bears against the top of a plate (322) of 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.

Abstract: An optical electronic scale reading apparatus comprising a scale read by a read head to determine the relative displacement therebetween. The read head comprises reflective surfaces so arranged that light from a source is reflected therefrom and interacts with the scale at first, second and third positions. At the third position, a fringe field is developed which has the same pitch as the scale. A detector is provided to receive light modulations during relative movement of the scale and read head as the fringe field interacts with the scale at the third position. These modulations are counted to determine the relative displacement between the scale and read head.

Abstract: Measuring apparatus for use in measuring relative movements of two objects and wherein a scale and scale reader are provided mounted respectively on the objects for providing an accurate determination of the relative positions of the two objects with reference to the marks on the scale, the positions of which are accurately known. An interferometer is also provided for measuring the relative movements of the scale and scale reader in order to provide an accurate determination of the relative positions of the two objects at positions between the scale marks. In order to correlate the readings of the scale reader and the interferometer, the scale reader outputs a signal to the interferometer each time a scale mark is detected and the interferometer reading is updated.

Abstract: A machine tool has a table movable relative to a head for machining a workpiece mounted on the head by a tool mounted on the table. The table also supports a magazine for blank workpieces, and the table is movable between a first position in which the head and the tool are in machining promitiy and a second position in which the head and the magazine are proximate. The head has a work holder adapted to grip a blank workpiece at said second position for transfer, by movement of the table, to said first position. After machining, the workpiece is correspondingly returnable to the magazine. The work holder is mounted on a spindle supported on the head and rotatable for machining purposes. In a modification the spindle supports a tool, and the head has a gripper which is separate from the spindle and is used for the transfer of workpieces between the magazine and a work holder mounted on the table.

Abstract: A cutting tool includes a motor and control inside the cutting tool for adjusting the cutting radius of the cutting tool. The cutting tool is adaptable for use with machine tools which do not include integral systems for moving parts of the cutting tool adjust the cutting radius.

Abstract: A position determination apparatus comprising a coordinate measuring machine having a scale. In addition, a read/write head and a laser interferometer system are provided, both of which can measure the position of a probe. The head writes signals derived from the interferometer onto the scale and is used either to lay down the periodic scale marks, or to write error correction values onto the scale. The scale is thus calibrated in situ on the machine.

Abstract: A three-coordinate measuring machine has a probe (22) connected to an output member (11). A driving system (10) is made up of three carriages (15, 17, 19) on guide rails (14, 16, 18). In parallel with this, there is provided a driven system (20) made up of three carriages (25, 27, 29) on guide rails (24, 26, 28). The carriages 19, 29) are connected together via the output member (11). The other pairs of carriages (15, 25 and (17, 27) are linked via respective devices (55). The devices (55) each apply a force between the respective carriages in dependence on acceleration or deceleration of the carriages of the driving system (10). This compensates for dynamic deflections of the guide rails of the driven system (20) which would otherwise be caused by the accelerations. Measuring devices such as scales and readheads are provided on the driven system (20) to determine the position of the probe (22).

Abstract: A co-ordinate measuring machine has a probe used to touch points on an article under manual control by a user, e.g. from a joystick. A computer 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. This can be done automatically without the need for the user to tell the computer anything about the shape of the feature concerned.

Abstract: Optical apparatus for use with a machine having parts movable along three mutually orthogonal axes. The apparatus uses a single laser to direct a main beam along a first one of the axes and a square deflector mounted on a movable part of the machine to direct the beam orthogonally into a second direction without any angular errors due to pitch or yaw of the square deflector. Thus only roll of the square deflector need be measured. Further square deflectors are used to deflect the beam around other axes of the machine whereby the co-ordinates of a measuring probe can be accurately checked against the machine scale readings. Various methods of measuring roll are described including generating side beams from the main beam and directing them in anti-parallel direction to the main beam onto detectors which detect the deviation of the anti-parallel beams due to roll of the square deflector.

Abstract: For setting the cutting tip (30) of a cutting tool (32) of a lathe, a tool-setting probe (10) has a stylus tip (18) for contacting the tool tip (30). The stylus tip (18) is generally cube-shaped. In addition to a conventional vertical datum surface (36) for setting the tool in the horizontal direction (arrow A), it has a 45.degree. sloping datum surface (38). The tool is touched in the direction of arrow A against both surfaces (36,38). The horizontal difference between the two contact positions is a measure of the height of the tool tip (30), enabling it to be set in the vertical direction.

Abstract: A contact sensing probe is disclosed for use with a measuring machine or machine tool for measuring the dimensions of a workpiece. The probe comprises a housing within which a stylus holder is mounted on a kinematic support. A spring urges the stylus holder into a rest position on the support and yieldingly resists tilting or lifting of the stylus holder from the support when the stylus engages a workpiece. A sensing device in the form of an accelerometer is supported within the housing on the stylus holder to sense one of the effects of stylus engagement with the workpiece, and to produce a signal which is used to stop the machine and read the signal and read the coordinates of the instantaneous stylus position. The effects sensed in different embodiments of the invention are, sudden lifting of the stylus holder due to physical displacement of the stylus, or the shockwave produced in the stylus on contact with the workpiece.

Abstract: The apparatus disclosed is a co-ordinate measuring machine having a column (33) movable relative to an object (11) for determining the contour (12) thereof. A tube (15) movable relative to the column (33) has a lens (18) focussing light to a sensing point (19) intended to lie at the contour (12). When, on moving the column (33) across the contour (12), the contour (12) rises relative to the column (33) and the lens (18), the change is at first detected by an optical position sensor (23) which produces an error signal (26A) to a motor (27) causing the latter to move the tube (15) in the sense restoring the sensing point (19) to the new position of the contour (12). The movement of the tube (15) is sensed by a further position sensor (30) which outputs a signal (30Z) connected to move the column (33) in the sense of restoring its previous position relative to the tube (15).