Method for controlling brakes in a trailer vehicle

1. A method for controlling brakes in a trailer vehicle, wherein the trailer vehicle comprises a pneumatic brake system, service brakes and an electronic brake system with anti-lock control, wherein at least one axle of the trailer vehicle is fitted with spring-loaded brakes and revolution rate sensors, wherein the spring-loaded brakes include a pneumatically actuated valve unit, and wherein the pneumatic brake system further comprises a reservoir container with a reservoir container pressure, said method comprising the steps of:

monitoring with the electronic brake system whether there is a braking demand,

monitoring with the electronic brake system whether at least one wheel of at least one axle is locking up,

if there is no braking demand and at least one wheel of the at least one axle is locked while traveling, controlling the pneumatic braking system with the electronic brake system to pressurize the spring-loaded brakes and to brake the trailer vehicle by the service brakes automatically and with anti-lock control, and

pressurizing the pneumatically actuated valve unit if a control pressure above a limit value is applied to a control input of the pneumatically actuated valve unit, the reservoir container pressure being delivered to the control input of the pneumatically actuated valve unit for triggering the pressurization of the spring-loaded brakes, wherein the control input of the pneumatically actuated valve unit is alternatively coupled to the reservoir container or a control pressure line depending on a position of a solenoid valve.

2. The method as claimed in claim 1 , wherein the braking demand exists if a pressure above a limit value is measured in a pneumatic control pressure line in the trailer vehicle or in a towing vehicle of the trailer vehicle or if a signal for actuation of the service brakes is transmitted on an electric brake line.

3. The method as claimed in claim 1 , further comprising decelerating the trailer vehicle to a standstill by controlling the pneumatic braking system.

4. The method as claimed in claim 1 further comprising the step of monitoring a longitudinal deceleration of the trailer vehicle and automatically braking the trailer vehicle and pressurizing the spring-loaded brakes only if the longitudinal deceleration exceeds a limit value.

5. A valve arrangement for a pneumatic brake system of a trailer vehicle including service brakes and spring-loaded brakes, wherein the pneumatic brake system comprises a reservoir container with a reservoir container pressure, said valve arrangement comprising:

a pneumatically actuated valve unit for pressurizing the spring-loaded brakes with the reservoir container pressure if a pressure above a limit value is applied to a control input of the pneumatically actuated valve unit, and

a solenoid valve, the solenoid valve being connected to a control pressure of the pneumatic brake system and to the reservoir container pressure, wherein the solenoid valve is switchable between the control pressure of the pneumatic brake system and the reservoir container pressure, and wherein the solenoid valve is connected to the control input of the pneumatically actuated valve unit, such that the control pressure of the pneumatic brake system and the reservoir container pressure are alternatively applied to the control input of the pneumatically actuated valve unit depending on a position of the solenoid valve.

6. A trailer vehicle with a pneumatic brake system, an electronic brake system and a valve arrangement, the valve arrangement being the valve arrangement as claimed in claim 5 .

7. An electronic control unit for carrying out the method as claimed in claim 1 .

8. An electronic control unit for controlling the valve arrangement as claimed in claim 5 .

9. An electronic control unit for a trailer vehicle as claimed in claim 6 .