Patent ID: 7334849
Filing Date: 2008-02-26
Classification: B60T

Abstract:
1. System for controlling the brakes on a rail or light rail motive power unit, where these brakes are provided with a pneumatic braking system including a pneumatic main pipe and a pneumatic brake pipe; the system comprising an electronic control unit, manually controlled actuating means, a pneumatic relay valve interposed between the main pipe and the brake pipe, and provided with a pneumatic control inlet, an electropneumatic control unit, connected to the main pipe and operable under the control of the electronic control unit to supply a variable brake control pressure; pneumatic back-up means connected to the pneumatic main pipe and operable to supply, under the control of said manually controlled actuating means, an outlet pneumatic back-up pressure for use in the control of the brakes; and enabling valve means, switchable between a normal operating condition and a back-up operating condition for connecting the control inlet of said relay valve selectively to the outlet of the electropneumatic control unit or to the back-up means; said relay valve being a valve with two control sections and having an additional control inlet, a control valve unit being interposed between the outlet of the aforesaid enabling valve means and the additional control inlet of the relay valve; said control valve unit being activatable when the enabling valve means are in the back-up operating condition, and being capable—when activated—of creating an increase or overcharge of the operating pressure emitted from the relay valve towards the brake pipe, and—when disabled—of subsequently discharging said pressure overcharge, according to predetermined time functions.