A trailer brake system that generates load-dependent braking forces. Variable trailer load information is used to generate load-dependent control signals which serve to control an electrically-controlled proportional valve. A load sensing valve serves to modify brake command signals in dependence on a control pressure that is regulated by the proportional valve.

A system for electrically controlling air brakes on a trailer having an electrically actuated valve for releasing pressurized air at a controlled rate. The trailer is connectable to a standard electrical connector on a towing vehicle that provides a proportional braking signal. The proportional signal is sent to a controller that actuates the electrically actuated valve. When the controller receives the proportional braking signal from the towing vehicle representing no braking force, the controller actuates the electrically actuated valve to produce no air pressure to the air brake. When the controller receives the proportional braking signal from the towing vehicle representing full braking force, the controller actuates the electrically actuated valve to provide air to the air brake corresponding to full braking force of the air brakes.

A vehicle braking system comprising a spring brake actuator having a spring brake chamber, a spring brake control assembly and an immobiliser valve which is movable between brake release position in which the spring brake control assembly is operable to cause the flow of pressurised fluid into the spring brake chamber or to vent the spring brake chamber to a low pressure region, and an immobilise position in which the spring brake control assembly is operable to connect the spring brake chamber to a low pressure region but cannot be operated to cause the flow of pressurised fluid into the spring brake chamber.

A parking brake device for motor vehicles includes at least one compressed air connection, an inlet venting-solenoid valve unit, a relay valve and at least one first compressed air outlet. The compressed air connection is connected to the inlet venting solenoid valve unit and the relay valve. A control line is provided such that the relay valve is connected or can be connected to the inlet venting solenoid valve unit, wherein the control line has a first branch and a second branch upstream of the relay valve. An output line is provided, which is connected to the at least one first compressed air outlet and has an output branch. A spring brake line is connected via the first branch to the control line and via the output branch to the output line, and a trailer valve line is connected via the second branch to the control line. The parking brake device has a spring brake valve, which is arranged in the spring brake line and is connected to the relay valve, and a throttle unit, which is situated in the spring brake line between the output branch of the output line and the first branch of the control line.

A parking brake device for motor vehicles includes at least one compressed-air connection, an inlet venting-solenoid valve unit, a relay valve and at least one first compressed-air outlet. The compressed air connection is connected to the inlet venting-solenoid valve unit and the relay valve. A control line is mounted such that the relay valve is or can be connected to the inlet venting-solenoid valve unit, the control line having a first branch and a second branch upstream of the relay valve. An outlet line is provided that is connected to the at least one first compressed-air outlet and has an outlet branch. The parking brake device further has a spring brake line that is connected to the control line via the first branch and to the outlet line via the outlet branch, and a trailer valve line that is connected to the control line via the second branch. The parking brake device also has a spring brake valve that is arranged in the spring brake line and is connected to the relay valve, and a throttle unit that is arranged in the spring brake line between the outlet branch of the outlet line and the first branch of the control line.

A method of brake control of a vehicle combination (2) composed of a tractor vehicle (4) with an electronically controlled braking system (5) and a trailer vehicle (6, 8) with a pneumatically controlled pneumatic braking system (7, 9), involves introducing the brake control pressure (p.sub.BC) of the trailer vehicle (6, 8) into a tractor brake control line (19) extending to a tractor vehicle-side “brake” coupling head (26) via an electronically controlled trailer control valve (13) of the tractor vehicle (4). At the beginning of a braking operation, a pressure pulse (34) exceeding a target brake control pressure (p.sub.BC_soll) is introduced into the tractor brake control line (19). The volume of a trailer brake control line (28, 29, 32) coupled to the “brake” coupling head (26) is ascertained, and the absolute value (Δp.sub.PI) and/or the duration (Δt.sub.PI) of the pressure pulse (34) introduced are/is established depending on the ascertained volume.

A utility vehicle control device for a parking brake device of a trailer vehicle includes a pneumatic supply connection, a control connection for controlling a spring brake cylinder, a directly manually actuatable parking valve, a first connection line and a control valve for controlling the parking valve. The parking valve is arranged in the first connection line, and wherein as a result of the parking valve, the supply connection and the control connection can be connected via the first connection line. A control line branches from the first connection line. The control line is connected to a first pneumatic control input of the control valve, wherein the control valve has a second pneumatic control input. In the event of an unexpected reduction in operating pressure in the first connection line and/or in the control line, the control valve can be controlled by the first or second control input of the control valve such that a switching state of the parking valve can be pneumatically controlled by the control valve independently of an operating state of the supply connection, whereby the control connection is ventilated by the parking valve.

A brake system for a vehicle, the vehicle including a service brake control module and a parking brake with at least one spring brake chamber, the service brake control module controlling at least a first pressure module to brake a first set of wheels. The brake system comprises a parking brake control module configured to control the spring brake chamber to brake a second set of wheels and to control the first pressure module to brake the first set of wheels.

Disclosed is a valve arrangement for aerating spring accumulator brake cylinders in a trailer vehicle with a pneumatic braking system, the valve arrangement having a first connection for a line connected to a reservoir of the trailer vehicle, a second connection for a line leading to the spring accumulator brake cylinders, and a first pneumatic control input, wherein the first connection can be connected to the second connection depending on the pressure on the first pneumatic control input. The first control input is connected to a line connected to a control connection of the trailer vehicle or to a line connected to the reservoir. A valve unit, a pneumatic braking system, a method of operating the same, and a trailer vehicle including the same are also disclosed.

An electronic brake system for a trailer with a pneumatic brake installation is disclosed. The electronic brake system comprises a brake controller (18) in the trailer (11) connected to a first communication device (20) that is part of a first communication channel (23) for wirelessly receiving brake signals of a towing vehicle (10). The electronic brake system also comprises a second communication channel for receiving brake signals of the towing vehicle. The brake controller (18) converts the brake signals of the first communication channel (23) into brake commands for the pneumatic brake installation only if brake signals arrive via the second communication channel (24) at the same time or within a defined time window. The time window begins as soon as a brake signal arrives on one of the first and second communication channels (23, 24).