Tubular wheel speed sensor for an anti-skid system

Claim 1

An anti-skid system for regulating braking forces applied to a rotatable body comprising: control circuit means for providing a skid signal in response to a signal representative of the velocity of said body; a rotor affixed to and rotatable with said body, said rotor having at least one array of apertures on the outer periphery thereof; sensing means mounted proximate to said rotor and cooperating with said rotor to establish an air gap, said sensing means including a magnetic flux source and means for producing a split magnetic flux path, said producing means having first and second pole pieces positioned relative to said magnetic flux source so as to be parallel to and equidistant from said magnetic flux source, said magnetic flux source and said first and said second pole pieces being retained in a tubular housing permitting axial and angular movement of said sensing means to obtain the proper orientation of said sensing means for different rotor sizes and/or aperture spacings, said proper orientation of said sensing means occurring when said first and said second pole pieces are alternatively in register with said apertures in said rotor resulting in the interruption of said split magnetic flux path by said apertures when said rotor is rotated causing a flux change; means for mounting said sensing means, said mounting means permitting axial movement of said sensing means relative to said rotor while preventing angular movement of said sensing means after said proper orientation of said sensing means is established; gauging means adjacent said sensing means, said gauging means projecting from said sensing means and in communication with said rotor for limiting axial movement of said sensing means; and coil means producing an output signal resulting from said flux change, said coil means being minimally responsive to any flux change resulting from relative axial movement between said sensing means and said rotor.