Wheel-Brake Cylinder (18, 20)
Wheel-brake cylinders can be distinguished into simple diaphragm cylinders that convert air pressure into a clamping force at the brakes and combination brake cylinders with integrated springs.
The combination brake cylinder consists of a single-chamber diaphragm cylinder for the service brake and a spring-type piston cylinder for the parking brake. They are arranged one behind the other and act on a common pressure rod. They can also be operated independent of each other. When operated simultaneously, their forces add up. The central release screw allows the tightening of the spring-type cylinder so that in case of an emergency the brake can also be released in the absence of compressed air.
When compressed air flows in front of the spring-loaded piston (release of the parking brake), the piston moves against the spring force, compresses the spring and releases the brake. When the service brake is actuated, compressed air flows behind the diaphragm and displaces the piston disk and pressure rod against the brake linkage.