Abstract: A numerically controlled machine tool having a tool secured to a support for machining a surface of a workpiece. The tool is also used for sensing the workpiece surface for measuring the distance between the workpiece surface and a datum surface. To this end, the tool is at first moved to a position clear of the workpiece surface and an electric circuit between the tool and the workpiece switched on. The tool is then moved toward the workpiece surface by a control system adapted to continually read the position of the tool by means of a counter. When the tool touches the workpiece the circuit is made and produces a signal used to read the instantaneous content of the counter into a computer. The computer determines the difference between the actual and demanded dimension of the workpiece surface and corrects the next machining position of the tool accordingly.

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: A contact-sensing probe has a movable member including a stylus and is supported on a fixed member at two spaced-apart locations. At each location a spherical element on the one member is situated between convergent surfaces of the other member. A spring urges the movable member into engagement with the fixed member so that at each location the element slides on the convergent surfaces and by virtue of the convergence thereof attains a positive rest position therebetween. The movable member is displaceable from the rest position against the force of the spring when a force is applied to the stylus and is returnable into the rest position by the spring. The elements and surfaces may be electrical contacts, displacement of the stylus being sensed by any one of the contacts being broken. Alternatively displacement is sensed by a proximity sensor.

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 tool connecting mechanism comprising two connecting members mutually engageable by movement of one member relative to the other along and about an axis. The members have respective support elements constituted as a kinematic support whereby, when engaged, the members are supported one on the other against relative displacement transversely to or about said axis.

Abstract: A machine for measuring a workpiece is adapted to move a probe (10) relative to a workpiece to be measured, the measurement being determined by an electronic scale (25) when the probe contacts the workpiece (8). If the measurement is taken while the probe is in a state of acceleration, the deflection of those parts (e.g. 11) of the machine which extend between the probe and the scale falsifies the measurement. The invention provides an accelerometer (30) to determine the acceleration and thereby the deflection. A computer is arranged to determine the true measurement by taking account of the deflection.

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 contact-sensing probe has a movable member including a stylus and is supported on a fixed member at two spaced-apart locations. At each location an a spherical element on the one member is situated between convergent surfaces of the other member. A spring urges the movable member into engagement with the fixed member so that at each location the element slides on the convergent surfaces and by virtue of the convergence thereof attains a positive rest position therebetween. The movable member is displaceable from the rest position against the force of the spring when a force is applied to the stylus and is returnable into the rest position by the spring. The elements and surfaces may be electrical contacts, displacement of the stylus being sensed by any one of the contacts being broken. Alternatively displacement is sensed by a proximity sensor.

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 probe for determining at what point in space contact is made between an object and a stylus. The stylus is located in an acurately defined rest position relative to a housing and slight deflection of the stylus away from this rest position is detected preferably by electrical switches.

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 determining at what point in space contact is made between an object and a stylus. The stylus is located in an accurately defined rest position relative to a housing and slight deflection of the stylus away from this rest position is detected preferably by electrical switches.

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.