Anti-skid device for a vehicle braking system

Claim 1

An antiskid device for a vehicle braking system comprising an electronic sensing unit for sensing the vehicle wheel speed and producing therefrom a control signal, and an actuating unit responding to the control signal for decreasing or cancelling the pressure in the vehicle braking system, said electronic sensing unit including means for generating a speed signal which is proportional to wheel speed, means for generating from the speed signal, an acceleration signal which is proportional to wheel deceleration or acceleration, and means selectively responsive to the acceleration signal for generating said control signal, characterized in that said selective responsive means is responsive to a first value of said acceleration signal to initiate the production of said control signal and to a second value of said acceleration signal to interrupt the production of said control signal, said selective responsive means comprises first and second branch circuits having their inputs receiving said acceleration signal and their outputs respectively connected to the two inputs of a bistable device provided for generating said control signal, said first branch circuit including in the order of a Schmitt trigger, a first differentiator and a first clipping diode and said second branch circuit including in the order of an acceleration signal shaper, a second differentiator and a second clipping diode.