Electro-pneumatic hand brake system

An electronic braking system for a vehicle with spring-applied brakes comprising:

• an electro-pneumatic hand brake system including a pneumatic relay valve having a relay valve outlet, a bistable solenoid valve for controlling said relay valve;
• said electro-pneumatic hand brake system further including a control unit for controlling the bistable solenoid valve and a plurality of ports associated with the spring-loaded brakes;
• said relay valve outlet being connected to said plurality of ports;
• said bistable solenoid valve having an inlet for connecting to a line carrying ventilation pressure;
• said electro-pneumatic hand brake system further including a self-retaining switching valve having a control input provided before said inlet of said bistable solenoid valve, a self-retaining switching valve inlet, and a self-retaining switching valve outlet;
• wherein:
• a) said self-retaining switching valve is moveable against a force of a restoring element from a blocking position into a flow-through position when there is sufficient pressure at said control input to move said self-retaining switching valve back into the flow-through position;
• b) said self-retaining switching valve has a self-retaining switching valve outlet connected to said inlet of the bistable solenoid valve;
• c) said control input of said self-retaining switching valve is also connected to a signal line via which a signal pressure is feedable to said control input as a control pressure at least for a period of time;
• d) said self-retaining switching valve in said flow-through position connects said self-retaining switching valve outlet to said self-retaining switching valve inlet;
• and,
• e) said self-retaining switching valve in said blocking position connects said self-retaining switching valve outlet with a self-retaining switching valve bleed outlet.

A vehicle comprising:

• a pneumatic brake installation;
• spring-loaded brakes;
• an electronic braking system having an electro-pneumatic hand brake system including a pneumatic relay valve having a relay valve outlet, a bistable solenoid valve for controlling said relay valve;
• said electro-pneumatic hand brake system further including a control unit for controlling the bistable solenoid valve and a plurality of ports associated with the spring-loaded brakes;
• said relay valve outlet being connected to said plurality of ports;
• said bistable solenoid valve having an inlet for connecting to a line carrying ventilation pressure;
• said electro-pneumatic hand brake system further including a self-retaining switching valve having a control input provided before said inlet of said bistable solenoid valve, a self-retaining switching valve inlet, and a self-retaining switching valve outlet;
• wherein:
• a) said self-retaining switching valve is moveable against a force of a restoring element from a blocking position into a flow-through position when there is sufficient pressure at said control input to move said self-retaining switching valve back into the flow-through position;
• b) said self-retaining switching valve has a self-retaining switching valve outlet connected to said inlet of the bistable solenoid valve;
• c) said control input of said self-retaining switching valve is also connected to a signal line via which a signal pressure is feedable to said control input as a control pressure at least for a period of time;
• d) said self-retaining switching valve in said flow-through position connects said self-retaining switching valve outlet to said self-retaining switching valve inlet;
• and,
• e) said self-retaining switching valve in said blocking position connects said self-retaining switching valve outlet with a self-retaining switching valve bleed outlet.