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Apparatus for measuring the speed of rotation of a wheel or the angular orientation thereof relative to a fixed point. A first portion of a transmitter unit is positioned along the periphery of the wheel and a second portion of the transmitter unit is positioned at a stationary location outside of t

Apparatus for measuring the speed of rotation of a wheel or the angular orientation thereof relative to a fixed point. A first portion of a transmitter unit is positioned along the periphery of the wheel and a second portion of the transmitter unit is positioned at a stationary location outside of the wheel. The two portions of the transmitter unit together from one or more lined screens which, when one is viewed through the other, create a moire interference pattern. Optical means are provided to read the interference pattern created as the wheel is moved to thereby determine the speed or angular orientation thereof.

대표청구항 ▼

A device for indicating the speed of a rotating wheel, comprising an open-sided cylindrical member extending from a face of said wheel, a transmitter unit including a first portion positioned along the outwardly facing periphery of the cylindrical member and a second stationary portion overlying sai

A device for indicating the speed of a rotating wheel, comprising an open-sided cylindrical member extending from a face of said wheel, a transmitter unit including a first portion positioned along the outwardly facing periphery of the cylindrical member and a second stationary portion overlying said first portion and located adjacent to said wheel and cylindrical member and spaced radially therefrom, said first and second portions including one or more screens formed of opaque parallel lines separated by transparent areas, the opaque lines forming the screen of the first portion being arranged substantially normal to the direction of movement of the periphery of the cylindrical member and the opaque lines forming the screen of the second portion being arranged substantially parallel to the opaque lines of the first portion, the relationship and location of the two sets of lines being such that rotary movement of the cylindrical member will present a moire interference pattern when the screen of the first portion is viewed through the screen of the second portion, the number of opaque lines per unit length of the first screen being different from the number of opaque lines per unit length of the second screen, and light-sensitive reading means for detecting movement of the interference pattern and generating electrical pulses which may be counted to indicate wheel speed, said reading means including a light-emitting element for lighting the screens and a light-receiving element for sensing movement of said moire pattern, one of said elements being located within said cylindrical member between the axis of the wheel and the periphery and the other of said elements being located radially spaced outwardly from said second portion.