Patent ID: 8240777
Filing Date: 2012-08-14
Classification: B60T

Abstract:
1. A device for controlling hydraulic braking of a trailer hitched to a tractor, which device comprises a hydraulic circuit having a brake pipe suitable for being connected to a pressurized fluid source or to a pressure-free reservoir via a proportional pressure reducer controlled by an electronic control unit and including a link solenoid-valve arrangement comprising at least one link solenoid-valve suitable for connecting the proportional pressure reducer to the reservoir or, via a calibrated pressure reducer, to the pressurized fluid source, wherein the circuit includes a hydraulic brake selector valve that, when in a link position in which the inlet and the outlet of the brake selector valve are interconnected, is suitable for causing a link pipe to be connected to a fluid feed or to a pressure-free enclosure, and at least one control solenoid-valve for controlling the brake selector valve, which control solenoid-valve is controlled by the electronic control unit, the control solenoid-valve for controlling the brake selector valve being suitable for taking up a first working configuration in which said control solenoid-valve makes it possible to feed a first control chamber of the brake selector valve with fluid so as to cause said brake selector to go into an isolation position in which the inlet and the outlet of the brake selector valve are isolated from each other by the brake selector valve, a second working configuration in which said control solenoid-valve makes it possible for a second control chamber of the brake selector valve to be fed with fluid so as to cause said break selector to go into said link position, and a neutral configuration in which neither of the two control chambers of the brake selector valve is fed with fluid, and in which the inlet of the brake selector valve is connected to the fluid feed, wherein the device includes at least one holder for holding the brake selector valve in position when the control solenoid-valve go from the first working configuration or from the second working configuration thereof to the neutral configuration thereof; wherein the link pipe is connected to link valve means themselves connected to the brake pipe so as to enable said brake pipe to be fed with fluid or to be connected to the reservoir depending on whether the link pipe is connected to the fluid feed or to the pressure-free enclosure; and wherein the device includes an indicator for delivering to the electronic control unit information indicating whether the brake of the trailer is of a first type requiring brake release by fluid feed, or of a second type, the control unit taking that information into account in controlling the control solenoid-valve for controlling the brake selector valve.