Abstract: An electronic caliper configuration making such calipers more reliable in the presence of liquid and particulate contaminants. Included in the caliper configuration is an elongated cavity added to the main beam of the caliper. The cavity is sealed with a cover. The measuring scale element of the measuring transducer, and the associated shorter pickoff element are mounted in this cavity. The depth bar, ordinarily attached to the sliding jaw in conventional calipers, is inserted into the cavity through a hole or holes aligned parallel to the longitudinal axis of the caliper and internally joined to the moving transducer element. A conventional lip seal provides an effective seal around the diameter of the depth bar. An external portion of the depth bar is coupled to the sliding jaw of the caliper via axially rigid linkage or alternately an axially rigid flexure. In this way, the internally isolated transducer elements can be actuated by the external sliding caliper jaw.

Abstract: A capacitive position transducer with reduced sensitivity to particulate and fluid contaminants. The electrodes of the position transducer are provided with a relatively thick coating of dielectric material so that the series impedance of the dielectric coatings is at least equal to the maximum capacitive impedance between the coatings whether or not there are any contaminants positioned therebetween. In one embodiment, the coatings are spaced-apart from each other to create an air gap while in another embodiment the coatings are resiliently biased toward each other so that the coatings slide along each other.

Abstract: A combined optical and capacitive absolute positioning encoding system uses a plurality of metallized strips deposited onto a glass scale substrate. A movable transceiver is positioned adjacent to the scale. The transceiver generates interrogating electrical an optical signals which interact with the scale. The movable transceiver also carries with it receiver mechanisms for receiving the signals after interaction with the scale. Signal processing electronics are provided to determine the relative positions of the scale and transceiver by comparing the transmitted, interrogating signals with the received signals. The system is able to determine the relative positions of the scale and transceiver even if power to the system is interrupted, or if the scale and transceiver are moved relative to one another very rapidly.

Abstract: Capacitive-type measuring apparatus for making absolute measurements comprises first and second support members which are relatively displaceable with respect to a measurement axis; an array of first electrodes disposed on the first support member; an array of second electrodes disposed on the second support member such that differing portions of the second electrode array are capacitively coupled with the first electrode array in dependence on the relative positions of the support members; an array of third electrodes disposed on the second support member so as to be electrically connected to corresponding second electrodes and spatially offset therfrom by an amount which varies according to the position of the third electrodes from a reference position; and a fourth electrode arrangement disposed on the first support member for providing in combination with the other arrays a plurality of discrete signal transmission paths each having a capacitive transfer function with two components, one of which varies a

Abstract: Capacitive-type measuring apparatus for making absolute measurements comprises first and second support members which are relatively displaceable with respect to a measurement axis; an array of first electrodes disposed on the first support member; an array of second electrodes disposed on the second support member such that differing portions of the second electrode array are capacitively coupled with the first electrode array in dependence on the relative positions of the support members; an array of third electrodes disposed on the second support member so as to be electrically connected to corresponding second electrodes and spatially offset therefrom by an amount which varies according to the position of the third electrodes from a reference position; and a fourth electrode arrangement disposed on the first support member for providing in combination with the other arrays a plurality of discrete signal transmission paths each having a capacitive transfer function with two components, one of which varies

Abstract: A capacitance-type measuring apparatus includes first and second support members which are movable with respect to one another along a measurement axis; a first electrode array and a second electrode disposed on the first support member; and a third electrode array disposed on the second support member and capacitively coupling the first electrode array and second electrode for transmission of a signal between the first electrode array and second electrode through the third electrode array. One of the first electrode array or the second electrode is formed to have end portions configured such that the degree of coupling between the first electrode array and second electrode through the third electrode array decreases linearly along the extent of each end portion relative to the measurement axis. This configuration permits improved measurement accuracies by reducing the effects of tilt between the first and second support members which changes the spacing between such members along the axis of measurement.

Abstract: Capacitive-type measuring apparatus for making absolute measurements comprises first and second support members which are relatively displaceable with respect to a measurement axis; an array of first transmitter electrodes disposed on the first support member; an array of first receiver electrodes disposed on the second support member such that differing portions of the first receiver electrode array are capacitively coupled with the first transmitter electrode array in dependence on the relative positions of the support members; an array of second transmitter electrodes disposed on the second support member so as to be spatially offset from and electrically connected to corresponding first receiver electrodes; and a second receiver electrode arrangement disposed on the first support member for sensing the voltage distribution of the electric field created by the second transmitter electrode array in response to excitation of the first transmitter electrode array with N excitation signals.

Abstract: A capacitive type measuring apparatus comprises first and second electrode arrays mounted on first and second support members which are relatively displaceable with respect to each other. The first electrode array comprises a series of discrete first electrodes uniformly spaced with a pitch P.sub.r defining a scale wavelength and the second electrode array comprises a series of discrete second electrodes arranged so as to define a plurality of electrode groups each having N electrodes, where N is an integer greater than 2.

Abstract: A system for measuring the relative movement of one object with respect to another, such as the movement of a slide with respect to a scale of a measuring instrument utilizes the capacitative effect of a series of electrodes associated with a slide and another series of electrodes associated with the cooperating scale, the changes in capacity caused by relative movement between the two members being analyzed by an electronic circuit.

Abstract: A system for measuring the relative movement between two elements, such as the scale and slide of a hand-held measuring instrument includes the provision of a number of groups of supply electrodes on the slide, each of the electrodes in each group being supplied from a respective one of a multiple number of output signals from a signal generator so that all of the supply electrodes are furnished with voltages according to a cyclic pattern, the slide also having at least one receiving electrode which feeds a signal processing unit. The scale is provided with an electronic pattern comprising internally galvanically connected parts, one being a detecting part, located close to the area where the supply electrodes of the slide are moved, the other of the two parts being a transferring part which is located close to the area where the receiving electrode of the slide is moved.

Abstract: An electronic caliper having a reduced offset position transducer that uses two sets of coupling loops on a scale to inductively couple a transmitter winding on a read head on a slide to one or more receiver windings on the read head. The transmitter winding generates a primary magnetic field. The transmitter winding is inductively coupled to first loop portions of first and second sets of coupling loops by a magnetic field. Second loop portions of the first and second sets of coupling loops are interleaved and generate secondary magnetic fields. A receiver winding is formed in a periodic pattern of alternating polarity loops and is inductively coupled to the second loop portions of the first and second sets of coupling loops by the secondary magnetic fields. Depending on the relative position between the read head and the scale, each polarity loop of the receiver winding is inductively coupled to a second loop portion of either the first or second set of coupling loops.