Pulse wheel system with shaft mounting

Claim 1

A pulse wheel system for developing at least first and second pulse trains having a predetermined phase shift between them, comprising: a pulse wheel including a rotational axis, and a series of perimetrically spaced discontinuities, a shaft having a longitudinal axis, a rotatable element journaled for rotation about said shaft, means mounting said pulse wheel for rotation with said rotatable element, coaxial with said shaft, mounting plate mounted on said shaft, and first and second detector means having predetermined center lines, said first and second detector means being mounted on said mounting plate to detect the discontinuities of said pulse wheel and provide first and second pulse trains in response thereto, said mounting plate having an opening for receiving said shaft and openings for orienting the center lines of said first and second detector means relative to the longitudinal axis of said shaft, with said mounting plate being devoid of means for changing the dimensional between its openings, with the center of the openings which orient the center lines of the first and second detector means being located a like distance from the longitudinal axis of the shaft, spaced apart on the periphery of a circle whose center coincides with the longitudinal axis of the shaft, and with the spacing between the center of the openings being selected to provide the predetermined phase shift between the first and second pulse trains, and wherein the series of perimetrically spaced discontinuities include teeth having a width T spaced by a dimension N, each detector means includes a beam of electromagnetic radiation having a diameter D, with the pulse wheel system providing pulse trains having a resolution R, and wherein the width T is equal to 1/2R+2D and the width N is equal to 1/2R-2D, to provide pulse trains having equal on and off times.