Anti-lock system

In combination with a source of service pressure for actuating a brake for decelerating a vehicle wheel and means for selectively applying service pressure to the brake,

• (a) sensing means attached for rotation about the axis of rotation of said wheel outboard of said wheel;
• (b) a source of control pressure located inboard of said wheel and offset with respect to the axis of rotation thereof to control the application of said service pressure to said brake;
• (c) means including a passageway therein connecting said sensing means to said source of control pressure through a path removed from the axis of rotation of said wheel;
• said passage means including a passageway extending through the hub of said wheel, a fixed circular member secured to said vehicle, sealing means between said wheel and circular member, a sealed chamber formed between said rotatable wheel and fixed portion of said vehicle by said sealing means, said wheel and said circular member, and said source of control pressure being connected to said sealed chamber through said circular member;
• (d) said sensing means being responsive during normal rotation of said wheel to maintain said control pressure to permit service pressure to be applied to said brake, and
• (e) said sensing means being responsive when said wheel is decelerated beyond said predetermined rate to relieve said control pressure to prevent service pressure from being applied to said brake.