Abstract: The method for measuring dimensions of a workpiece (15) in a coordinate measuring machine having an optical probe (14) arranged to output radiation in a direction (21A) at an angle to a surface (15A) to be measured. The probe has a housing (17) which is arranged to lie clear of a projection formed by the surface (15A) to be measured and another, adjacent, surface (15B) so that the housing can pass clear of the projection and the measurement can be made without halting the machine at the surface to be measured.The probe (14) is adapted for the radiation to be in the form of a cone (21) symmetric about an axis (Z1) transverse to the direction of movement of the probe so that the probe can sense all around the axis and therefore can sense any surface parallel or inclined to the axis regardless of the direction in which the surface faces.

Abstract: A machine tool having 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 proximity 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: The machine tool is a machining center having an angularly positionable tool spindle 16, a work table 11 movable relative to the spindle, and a surface-sensing probe 25 mountable on the spindle for measuring dimensions or positions on a work piece situated on the table. The probe senses a surface when the latter lies a small distance ("the probe offset") away from the spindle axis.The method comprises providing on the workpiece a bore 24 defining opposite test surfaces -DX and +DX. The mid-point between the test surfaces has a known nominal position but an unknown actual position. The method further comprises operating the machine in a specified way to measure the test surfaces, the operation including rotating the spindle through 180.degree. between certain of the measuring operations. The measurements are then used for computing the probe offsets and the distance ("the work offset") between said nominal and actual positions.

Abstract: The machine tool is a machining center having an angularly positionable tool spindle, a work table movable relative to the spindle, and a surface-sensing probe mountable on the spindle for measuring dimensions or positions on a work piece situated on the table. The probe senses a surface when the latter lies a small distance ("the probe offset") away from the spindle axis.The method comprises providing on the workpiece a bore 24 defining opposite test surfaces -DX and +DX. The mid-point between the test surfaces has a known nominal position but an unknown actual position. The method further comprises operating the machine in a specified way to measure the test surfaces, the operation including rotating the spindle through 180.degree. between certain of the measuring operations. The measurements are then used for computing the probe offsets and the distance ("the work offset") between said nominal and actual positions.

Abstract: A probe for sensing the position of a workpiece comprises a housing adapted to be secured to a coordinate measuring machine. A stylus projecting from the housing is engageable with the workpiece for sensing the position thereof. The stylus is secured to a moveable member supported within the housing by three bellows having mutually perpendicular axes and each secured to the moveable member and the housing in position therebetween. Since a bellows is inherently stiff in torsion about its axis but is flexible axially and transversely, the bellows cooperate to constrain the stylus for parallel motion. More particularly, any one first bellows can expand or contract to accommodate movement of the stylus in the direction of the axis of that the first bellows, a second one of the bellows prevents tilting of the stylus by virtue of its torsional stiffness. At the same time both the second and third bellows flex transversely to accommodate the expansion or contraction of the first bellows.

Abstract: A numerically controlled machine tool comprises a tool movable into engagement with a workpiece, means for generating a first signal being a measure of the distance between the tool and a datum surface provided on a relatively fixed part of the machine, a first closed loop system adapted to move the tool toward the workpiece and having the first signal as feedback, means for generating a second signal being a measure of the distance between the tool and the workpiece, a second closed loop system (33) having the second signal as feedback, and means responsive to the second-mentioned distance attaining a threshold value, while being moved under the control of the first system, for changing control of the tool movement from the first to the second system.

Abstract: A probe for measuring dimensions of a workpiece in coordinate positioning apparatus, comprises a base (20), a stylus holder (21) having an axis (21A), an intermediate member (22, 30) having a fixed region (22A) connected to said base and a free region (22B) connected to said holder, said intermediate member being resilient so as to be responsive to a displacing force (FW) acting on said holder in the sense tending to tilt or axially move said holder relative to said base, and sensing means (30) connected between said free region and said base for sensing the occurence of a said displacing force.The intermediate member is only sufficiently resilient to make possible said sensing.

Abstract: A probe having a movable member including an elongate stylus and a plate extending in a plane transverse to the longitudinal axis of the stylus. The plate is seated on a seat having a circular edge provided on the fixed member. Displacement of the free end of the stylus, either transversely to or longitudinally of the stylus, is measured by a transducer having an electrical output signal. Like transverse and longitudinal displacements of the free end unavoidably produce unlike signals. To compensate for this, the signal is passed through a voltage divider whose output is made variable by a relay in a circuit containing the plate and the edge as electrical contacts. Transverse displacement of the free end tilts the plate on the edge, thus maintaining engagement therebetween. Longitudinal displacement separates the plate from the edge, thus breaking contact therebetween.

Abstract: A probe for use in measuring apparatus has a base member including a two-dimensional seat for an intermediate member which, in turn, includes a two-dimensional seat for a stylus holder. The two seats face in opposite directions so that the stylus holder can be displaced from the seated position in either of two opposite directions.

Abstract: A method and apparatus for measuring a dimension of a workpiece mounted on a numerically controlled machine tool having a probe for sensing the surface of the workpiece, an automatic means for moving the probe relative to a datum, the automatic means including a first measuring means for producing a signal defining units of distance corresponding to the relative movement of the probe with respect to the datum, and a second measuring means coupled to the first measuring means for accumulating a count corresponding to the relative movement of the probe in respect to the datum. The actual position of the workpiece surface is determined relative to a nominal position thereof, the nominal position being at a known distance from the datum. According to the method the probe is moved to a first position which is one of the actual and nominal positions of the workpiece surface.

Abstract: Apparatus for monitoring the state of a first circuit (19) by means of a second circuit (29) has an inductive coupling (23) linking the circuits across a gap (32). The second circuit embodies an oscillator (27) producing primary oscillations in that circuit and, through the coupling, secondary oscillations in the first circuit (19). If the state of the first circuit (19) is changed as by opening or closing of contacts (17,18), the resulting change in the impedance of the first circuit results in a change in the frequency of the primary and secondary oscillations. The second circuit (29) is connected to a detector (35) producing a signal (37AI) when the frequency changes. Instead of an inductive coupling, a capacitative coupling may be used.The apparatus is described as applied to a machine for measuring length. The first circuit (19) is embodied in a probe (12) whereby the machine contacts a workpiece to be measured. The first circuit is opened by such contact.

Abstract: In a co-ordinate measuring machine a probe is connected to the head of the machine by a pivotal arm, and the orientation of the probe is charged by moving the head so that the arm engages a fixed structure and a moment is applied to the arm which is thereby caused to turn and present the probe in the required orientation.

Abstract: A probe for use in measuring apparatus has a base member including a two-dimensional seat for an intermediate member which, in turn, includes a two-dimensional seat for a stylus holder. The two seats face in opposite directions so that the stylus holder can be displaced from the seated position in either of two opposite directions.

Abstract: A rotary mounting for supporting a workpiece for rotation has a number of support members which are small in relation to the workpiece and each of which forms an aerostatic bearing with a flat surface of a table. The support members are connected by respective links to a radial bearing connected to the table and supporting the mounting for rotation.

Abstract: In a co-ordinate measuring machine a probe is connected to the head of the machine by a pivotal arm, and the orientation of the probe is changed by moving the head so that the arm engages a fixed structure and a moment is applied to the arm which is thereby caused to turn and present the probe in the required orientation.

Abstract: Measuring apparatus comprises a probe having a stylus supported on a housing by a spring extending in a plane transverse to the axis of the stylus and allowing the stylus to pivot about a center lying on the axis and to move linearly in the direction of the axis. A sensor has fixed and movable parts off-set from the axis, the movable part being connected to the stylus by a transverse arm. The sensor senses both pivotal and axial movement, the pivotal movement corresponding to movement of the work-contacting end of the stylus transverse to the axis. At least one further sensor is provided to sense at least the axial movement of the stylus. An electrical network responsive to both sensor outputs is arranged to discriminate between transverse and axial movements of the stylus. Alternatively the sensors are arranged to give a single output for any movement of the stylus.

Abstract: In a contact-sensing probe having a stylus holder supported for tilting about support surfaces at any one of three locations, additional support surfaces are provided in positions between the three locations to increase the number of locations about which the holder is tiltable.

Abstract: A probe for use in measuring machines comprises a stylus holder tiltably supported on three first seats arranged about an axis and on one side of an intermediate member. The intermediate member is tiltably supported at its other side on three second seats provided on a housing on the same pitch circle as the first seats but intermediate between the first seats. The stylus holder is therefore supported with the stability inherent in a three-point support but is tiltable about any two adjacent ones of six seats thereby improving the sensitivity of the probes.

Abstract: The stylus of a work piece measuring probe is supported for movement in three dimensions by three pairs of leaf springs connected in series and arranged as if lying at the six sides of a rectangular box.