Antiskid systems and apparatus for vehicles

Claim 1

Vehicle brake control apparatus including: a. sensing means for producing electrical signals which are analogues of the speed of a vehicle wheel or associated component, b. means for differentiating said analogue signals, c. a first comparator device responsive to the differentiated signals for producing a first output signal therefrom whenever the wheel deceleration exceeds a predetermined value, d. an inverter device responsive to said first output signal from said first comparator device for producing a second output signal, e. braking pressure antilock control valve means responsive to said second output signal to effect brake pressure relief, f. means for generating an electrical reference signal having a value determined in accordance with vehicle deceleration, g. dual mode integrator means responsive to said analogue signals and to said reference signal for producing a third output signal representative of wheel speed when the integrator means operates according to one mode, and for producing a fourth output reference signal representative of vehicle speed and controlled by vehicle deceleration when the integrator means operates according to the second mode, h. a second comparator device responsive to said analogue signals, said output signals from said inverter device and said integrator means for producing a control signal for deactivation of said antilock control valve means to reapply the braking pressure whenever the wheel speed signal is equal in magnitude to the output signal from said integrator means, i. and means wherein the output of the second comparator device is connected to a relay coil arranged to be energized whenever the wheel deceleration exceeds said predetermined value and having a pair of associated contacts connected in the circuit of said integrator means, the analogue signals being normally supplied to said integrator means via a first of said pair of contacts and the vehicle deceleration reference signal being supplied via the integrator means to an input of said second comparator device whenever said relay coil is energized to effect brake release via the antilock valve control means.