Abstract: A hydraulically-actuated brake system for off-road, heavy vehicles that includes separate accumulators for braking the front and rear brakes and brake valves that are both manual and pilot actuated for controlling the flow of hydraulic fluid from the accumulators to the brakes. Also included are valves for comparing the pressure in the front and rear accumulators so that, should one of the systems become low, the brakes are immediately set. Also included is a manual valve for overriding the brake valves in the event that a malfunction occurs in one of the brake valves.

Abstract: An anti-skid hydraulic braking system for a vehicle having the usual wheel cylinders, master cylinder and brake pedal, with a brake release valve interposed ahead of each wheel cylinder for selectively reducing the pressure in the wheel cylinder in accordance with a slip signal generated at the associated wheel. For the purpose of generating a slip signal, positive displacement hydraulic pumps are coupled to the respective wheels, the pumps being connected in a series loop circuit charged with control fluid so that control fluid circulates idly at low pressure in the loop as long as the wheels rotate at the same speed, but with back pressure being developed at the input connection of a pump associated with a wheel which is in a relatively slipping condition of incipient skid.

Abstract: An anti-skid hydraulic braking system for a vehicle having the usual wheel cylinders, master cylinder and brake pedal, with a brake release valve interposed ahead of each wheel cylinder for selectively reducing the pressure in the wheel cylinder in accordance with a slip signal generated at the associated wheel upon going into a relatively slipping condition of incipient skid. Each brake release valve has an inlet port connected to the master cylinder, an outlet port connected to the wheel cylinder, and a control port. In the preferred embodiment the valve has a first or "signal" piston movable in response to slip signal pressure applied to the control port and a second piston for creating a cavity for temporary accommodation of brake fluid from the wheel cylinder.

Abstract: A pressure intensifier unit formed of a low pressure air cylinder and a high pressure hydraulic cylinder joined substantially end-to-end, with a large diameter air piston in the low pressure cylinder and a cylindrical piston, in the form of a straight-sided post, secured to the air piston and extending into the high pressure cylinder. An annular gland is provided at the junction between the cylinders for surrounding and sealing the cylindrical piston and for isolating the cylinders from one another. The inner diameter of the high pressure cylinder is greater than the diameter of the cylindrical piston so that, when the cylindrical piston moves into the high pressure cylinder upon application of air to the low pressure cylinder, clearance exists around the cylindrical piston, with hydraulic fluid being volumetrically displaced. The gland serves to mount a pair of axially spaced annular sealing elements with a replenishment port in between them connected to a source of replenishing fluid.