Safety mechanism for brake holder of automotive hydraulic brake system

Claim 2

In a hydraulic vehicle wheel brake system having a brake holder including a control valve actuated upon detection of said vehicle coming to a stop to hold the vehicle still until deliberate release of said brake holder, the improvement comprising: a. a signal generator for producing pulses proportional to the rotation of at least one of said vehicle wheels; b. a circuit for integrating said pulses into a corresponding voltage signal as a function of said wheel speed; and c. delay means for actuating said control valve only when said voltage signal drops to a predetermined value to delay said control valve actuation for times that are longer at higher speeds of said vehicle.

Claim 3

The system of claim 1 including means for varying the rate of discharge of said integrated voltage signal to vary said time delay for different road conditions.

Claim 4

The system of claim 2 wherein said discharge rate varying means includes a variable resistor.

Claim 5

The system of claim 2 wherein said signal generator is a dynamo-type pulse generator mechanically connected to said one vehicle wheel.

Claim 6

In a hydraulic vehicle wheel brake system for the wheels of a powered vehicle, comprising wheel cylinder means, a master cylinder, a piping system connected hydraulically between said master cylinder and wheel cylinder means, and an electromagnetically operated hydraulic brake pressure control means inserted in said piping system for control of the hydraulic brake pressure supplied to said wheel cylinder means, the improvement comprising a brake holder electrically connected with said hydraulic brake pressure control means, said brake holder comprising a first circuit means for generating an electrical signal current responsive to the rotational speed of one of said wheels, said first circuit means comprising a signal generator mechanically coupled with one of said wheels for unitary rotation therewith and adapted for generating a series of electrical current pulses in response thereto, a second circuit means for converting said signal current into a corresponding signal voltage, said second circuit means comprising an integrator electrically connected with said signal generator for conversion of said current pulses into a series of corresponding voltage pulses, said hydraulic brake pressure control means being adapted for interrupting fluid passage flow through said piping system to said wheel cylinder means when said voltage signal received from said brake holder drops beyond a predetermined value, a switch means between said integrator and said control means for actuation upon lowering of said voltage signal below said predetermined value, said control means having a solenoid coil responsive to said switch actuation, and a variable electrical means for making said voltage signal output from said converter circuit variable in response to road surface conditions, so as to modify the actuation period of said control means responsive thereto.

Claim 7

In a hydraulic vehicle wheel brake system for the wheels of a powered vehicle, comprising wheel cylinder means, a master cylinder, a piping system connected hydraulically between said master cylinder and wheel cylinder means, and an electromagnetically operated hydraulic brake pressure control means inserted in said piping system for control of the hydraulic brake pressure supplied to said wheel cylinder means, the improvement comprising a brake holder electrically connected with said hydraulic brake pressure control means, said brake holder comprising a first circuit means for generating an electrical signal current responsive to the rotational speed of one of said wheels, said first circuit means comprising a signal generator mechanically coupled with one of said wheels for unitary rotation therewith and adapted for generating a series of electrical current pulses in response thereto, a second circuit means for converting said signal current into a corresponding signal voltage, said second circuit means comprising an integrator electrically connected with said signal generator for conversion of said current pulses into a series of corresponding voltage pulses, said hydraulic brake pressure control means being adapted for interrupting fluid passage flow through said piping system to said wheel cylinder means when said voltage signal received from said brake holder drops beyond a predetermined value, a switch means between said integrator and said control means for actuation upon lowering of said voltage signal below said predetermined value, said control means having a solenoid coil responsive to said switch actuation, and a variable electrical means for making said voltage signal output from said converter circuit variable in response to road surface conditions, so as to modify the actuation period of said control means responsive thereto.

Claim 8

The hydraulic vehicle wheel brake system as claimed in claim 5 wherein said variable electrical means is a variable resistor provided between said integrator and said switch means for modifying the electrical current input from said integrator to said switch means in response to occasional road surface conditions.

Claim 9

The hydraulic vehicle wheel brake system as claimed in claim 5 wherein said signal generator is a dynamo-type pulse generator mechanically coupled with one of said vehicle wheels.