Importance

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Abstract

This invention relates to apparatus for detecting the contact or nip width between two contacting surfaces. The apparatus includes first and second insulating substrates each of which has a pattern of conductive material formed on a facing inner surface thereof, which substrates are adapted to be fitted between the contacting surfaces. For a first embodiment, the pattern of conductive material on one substrate includes a pair of conductive terminals spaced by a distance greater than the contact width to be measured and the conductive pattern on the other substrate includes a conductor which extends over at least a distance greater than the maximum width W to be measured. A resistance path is provided between the conductive terminals having a resistance R0 which is higher than that of the conductor and material is provided in the space between the conductor and the resistance path which material substantially permits current flow therethrough between the conductor and the resistance path in areas where the contacting surfaces are not in contact and which has a resistance less than R0 permitting current flow therethrough in areas where the contact surfaces are in contact. Circuitry is also provided for applying current to one of the terminals and for utilizing the difference in current flow between the terminals to determine contact width. For a second embodiment, the conductive pattern on one substrate includes N substantially parallel and evenly spaced conductive columns and the pattern on the other substrate is a plurality of substantially parallel and evenly spaced rows. The columns are divided into M groups, where M is an integer which is at least 2, and each of the rows is at an angle .theta. to a line perpendicular to the columns when extending across alternate ones of the groups and at an angle -.theta. when extending across the remaining groups. The number of columns in each group is selected to achieve a desired resolution, and .theta. is selected so that the distance in the direction of the columns between the ends of a row for each group is substantially equal to the spacing between adjacent rows.

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First Claim