Abstract: A trailer brake control module (300a; 300b; 300c) for a towing vehicle (502) facilitating braking of a towed vehicle or trailer (504) includes a pressure supply port (P11), a trailer control pressure port (P22), a primary control port (P42) for receiving either directly and/or indirectly a control brake pressure for operating the trailer brake control module (300a; 300b; 300c). The primary control port (P42) receives the control brake pressure from a pneumatically operated pressure medium, a pneumatic control pressure line (308.1) provides alternative control brake pressure for operating the trailer brake control module (300a; 300b; 300c), wherein the pneumatic control pressure line (308.1) receives the alternative control brake pressure from an electronically operated pressure medium, and a relay valve (310) is activated using either the control brake pressure received at the primary control port (P42), or the alternative control brake pressure from the pneumatic control pressure line (308.1).

Abstract: A brake pressure modulator (110; 106) includes a relay valve (202) for controlling a supply of pressurized air from a primary source (II) to at least one brake actuator (112a, 112b), a first valve sub-unit (204) configured to be electronically actuated and configured to receive a primary control pressure from the primary source (II) intended for operating the relay valve (202), and a second valve unit (206) configured to receive a secondary control pressure from a secondary source (‘BST’) and at least part of the primary control pressure from the primary source (II) and to transmit either the primary control pressure or the secondary control pressure to the relay valve (202). When the secondary control pressure is transmitted to the relay valve (202), the primary control pressure from the primary source (II) is disconnected.

Abstract: A control valve for applying a spring-loaded brake pressure to spring-loaded parts of a rear-axle wheel brake is pneumatically activated as a function of a parking-brake braking demand and a service-brake braking demand. A first control chamber is connected via a first control piston to a control arrangement in the control valve. During an adjustment of the first control chamber via the service-brake control pressure, the spring-loaded brake pressure at the working output is a function of the service-brake control pressure or of the parking-brake control pressure. The first control piston is connected to a third control chamber, wherein the pressure in the first control chamber acts on the first control piston in one direction, and the pressure in the third control chamber acts on the first control piston in the opposite direction. The first control chamber is selectively connectable to the third control chamber via a switchable bypass valve.

Abstract: A control valve for applying a spring-loaded brake pressure to spring-loaded parts of a rear-axle wheel brake is pneumatically activated as a function of a parking-brake braking demand and a service-brake braking demand. A first control chamber is connected via a first control piston to a control arrangement in the control valve. During an adjustment of the first control chamber via the service-brake control pressure, the spring-loaded brake pressure at the working output is a function of the service-brake control pressure or of the parking-brake control pressure. The first control piston is connected to a third control chamber, wherein the pressure in the first control chamber acts on the first control piston in one direction, and the pressure in the third control chamber acts on the first control piston in the opposite direction. The first control chamber is selectively connectable to the third control chamber via a switchable bypass valve.