Abstract: Normal operating fluid pressure is applied behind a brake release piston in a first pressure chamber in the brake assembly. Variable operator control fluid pressure is applied in a second chamber of the assembly behind a brake applying piston which opposes the brake release piston in the assembly. A dry chamber for stator and rotor discs of the brake lies between the two pistons with a skirt of the brake release piston surrounding the discs and engaging a pressure plate forming the endmost stator disc adjacent to the brake applying piston. Brake applying springs are intervened between the pressure plate and brake applying piston to impart to the disc brake a fail-safe capability as well as a brake "on" condition when the system is depressurized.

Abstract: A disc brake primarily for use in a power transmission train between a drive motor and a gear speed reducer features a standardized compact and simplified hydraulic module containing a single piston and a coacting floating cylinder head and an adjusting collar to regulate the movement of the piston. The standardized module is compatible with and operationally connectable to a variety of brake disc assemblies of differing size and torque arresting capacity. The disc brake is biased "on" by constantly acting spring means behind the piston in the hydraulic module when the hydraulic system is depressurized. The brake also possesses a fail-safe capability and has a very desirable "soft feel" during operation due to hydraulic cushioning between the piston and floating cylinder head.