Pneumatically-operated braking system for tractor-trailer combinations
AssigneeMeritor Heavy Vehicle Systems, LLC
InventorDenis John McCann
Life of this patent
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Abstract
A pneumatically-operated braking system for a tractor-trailer combination incorporates a trailer control valve (4) for providing braking pressure for the trailer. The control valve (4) is adapted to be actuated by a pressure differential acting across it to limit the flow of air in the supply line (2) when a leak is present in the trailer control line (12), and the pressure differential is generated between the pressure in the supply line (2) and pressure supply from another independent source (1).
Claims13
A pneumatically-operated braking system for a tractor-trailer combination, in which a trailer control valve for providing braking pressure for the trailer is actuated by a pressure differential acting across it to limit the flow of air in a supply line when a leak is present in a trailer control line, the pressure differential being generated between the pressure in a trailer control line and pressure supply from a trailer/park pressure supply tank, the trailer control valve including a control piston subjected on one face to pressure in the control line which, when in operation, causes the control piston to cooperate with a brake-applying piston to isolate the trailer control line from atmosphere by closing a through bore in a brake-applying piston, further movement of the control piston in the same direction unseating the brake-applying piston from a valve seating to supply pressure to the trailer control line.
A pneumatically-operated braking system comprising:
- an independent pressure supply tank having a supply pressure line therefrom;
- and
- a valve assembly having a dump valve attached to said supply pressure line, such that said supply dump valve substantially maintains a neutral position during normal application of said brake system, said valve assembly attached to a trailer control pressure line to restrict said supply pressure line in response to a failure of said trailer control pressure line;
- said valve assembly operable to restrict a flow associated with said supply pressure line in response to a pressure differential between said trailer control pressure line and said supply pressure line.
A method of limiting a supply pressure for a pneumatically-operated braking system having a valve assembly associated with a supply pressure line and a trailer control pressure line comprising the steps of:
- (1) supplying a supply pressure to the valve assembly from an independent supply tank;
- (2) supplying a control pressure to said valve assembly;
- (3) determining whether a pressure differential exists between said trailer control pressure line and said supply pressure line;
- and
- (4) restricting a flow associated with said supply pressure line in response to determining that said pressure differential exists and exhausting a trailer supply line to atmosphere.
A pneumatically-operated braking system for a tractor-trailer combination comprising:
- a trailer control valve for providing braking pressure for the trailer actuated by a pressure differential acting across said valve to limit the flow of air in a supply line when a leak is present in a trailer control line, the pressure differential being generated between the pressure in a trailer control line and pressure supply from a trailer/park pressure supply tank,
- said trailer control valve including a control piston subjected on one face to pressure in the control line which, when in operation, cause the piston to cooperate with a brake-applying piston to isolate the trailer control line from atmosphere by closing a through bore in a brake-applying piston, further movement of the control piston against a spring loading unseating the brake-applying piston from a valve seating to supply pressure to the trailer control line.
A pneumatically-operated braking system comprising:
- an independent pressure supply tank having a supply pressure line therefrom;
- and
- a valve assembly having a supply dump valve and a control valve, said supply dump valve attached to said supply pressure line such that said supply dump valve substantially maintains a neutral position during normal application of said brake system and a control valve attached to a trailer control pressure line;
- said valve assembly operable to restrict a flow associated with said supply pressure line in response to a pressure differential between said trailer control pressure line and said supply pressure line.
A method of limiting a supply pressure for a pneumatically-operated braking system having a valve assembly associated with a supply pressure line and a trailer control pressure line comprising the steps of:
- (1) supplying a supply pressure to the valve assembly from an independent supply tank;
- (2) supplying a control pressure to said valve assembly;
- (3) determining whether a pressure differential exists between said trailer control pressure line and said supply pressure line;
- and
- (4) restricting a flow associated with said supply pressure line and exhausting the trailer supply line to atmosphere in response to determining that said pressure differential exists.
Dependencies are inferred from the claim text.