Renco Encoders Inc.

Donald E Barnett

Robert M Setbacken

Kevin M Carbone

An optical encoder has a single data track which is scanned photoelectrically by a scanning unit. The data track consists of an incremental track and a plurality of overlying code tracks so that it is possible to generate incremental output signals as well as at least coarse absolute positional information by scanning only one track. The scanning unit comprises a first detecting unit with a phased array of photodetectors to scan the incremental graduation. A second detecting unit with a plurality of photodetectors is provided for scanning the code tracks. The code tracks can be used to generate commutation signals for brushless motors.

Encoder for providing incremental and absolute position data

A method and device for generating a reference signal for comparison with scanning signals generated by a position measuring device. The reference signal is generated using the same components used to scan a scale by averaging the scanning signals so that the reference signal is always less than the higher state of any scanning signal.

Method for generating a synthetic reference signal for comparison with

A simplified mechanism for rotationally aligning and gapping a pattern wheel with respect to a stationary mask are provided as part of a modular optical shaft encoder in accordance with the present invention. Moreover, the present invention includes a simplified method of connecting and aligning a modular encoder to a shaft. A radial alignment mechanism is provided between engagement surfaces of the hub of the pattern wheel and the encoder housing for independently providing radial alignment. The engagement surfaces are designed so that as the surfaces are urged into engagement with one another, the encoder housing (and thus the mask pattern) becomes radially aligned to the pattern wheel (and specifically its pattern). As an independent functional mechanism, a linear cam member is utilized for gapping the hub of the pattern wheel and thus the pattern thereon to the stationary mask pattern. The method of the present invention includes steps for independently radially aligning the optical pattern of the pattern wheel to the mask pattern of the mask and for separately gapping the pattern wheel with respect to the mask.

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West Chester, PA, United States of America

Donald E Barnett