Brake system for heavy duty semi-trailer brake systems
AssigneeMidland Brake, Inc.
InventorsSteven D. Wallestad, Joseph C. Spenser
Life of this patent
Estimating the term…
Abstract
A braking system is improved by addition of a spring brake pressure protection valve, to prohibit pressurization of the spring brakes prior to the build up of sufficient pressure to insure complete release of the spring brakes. This prevents the significant problems associated with known systems that permit operation of a tractor trailer with partially released spring brakes, which will cause unnecessary wear and reduced fuel economy. The spring brake pressure protection valve is located between the reservoir and the spring brakes, most preferably between the spring brake quick release valve and the spring brakes, or alternately, between the reservoir and the spring brake quick release valve.
Claims20
In a brake system for a trailer having a supply fluid line connected to a reservoir by a pressure protection valve and a check valve, said reservoir being operably connected to a spring brake, the improvement comprising:
- a spring brake pressure protection valve provided in a line connecting said reservoir with said spring brake, said spring brake pressure protection valve being maintained in a closed position until fluid pressure at a reservoir side of said spring brake pressure protection valve is sufficient to fully release said spring brake, said spring brake pressure protection valve being maintained in an open position when fluid pressure at said reservoir side thereof is sufficient to fully release said spring brake.
In a brake system for a trailer having a supply air line connected to a reservoir by a pressure protection valve and a check valve, said reservoir being operably connected to a spring brake by a spring brake line containing a spring brake quick release valve located between said reservoir and said spring brake, the improvement comprising:
- a spring brake pressure protection valve provided in a portion of said spring brake line connecting said spring brake quick release valve with said spring brake, said spring brake pressure protection valve being maintained in a closed position until air pressure at a spring brake quick release valve side of said spring brake pressure protection valve is sufficient to fully release said spring brake, said spring brake pressure protection valve being maintained in a open position so long as air pressure at said spring brake quick release valve thereof is sufficient to fully release said spring brake;
- and
- a check valve located in a line in parallel with said portion of said spring brake line containing said spring brake pressure protection valve, said check valve being closed when an air pressure on a spring brake quick release valve side of said check valve exceeds an air pressure on a spring brake side of said check valve, said check valve being open when an air pressure on said spring brake quick release valve side of said check valve is less than an air pressure on said spring brake side of said check valve.
In a brake system for a trailer having a supply air line connected to a reservoir by a pressure protection valve and a check valve, said reservoir being operably connected to a spring brake by a spring brake line containing a spring brake quick release valve located between said reservoir and said spring brake, the improvement comprising:
- a spring brake pressure protection valve provided in a portion of said spring brake line connecting said reservoir with said spring brake quick release valve, said spring brake pressure protection valve being maintained in a closed position until air pressure at a reservoir side of said spring brake pressure protection valve is sufficient to fully release said spring brake, said spring brake pressure protection valve being maintained in an open position when air pressure at said reservoir side thereof is sufficient to fully release said spring brake;
- and
- a check valve located in a line in parallel with said portion of said spring brake line containing said spring brake pressure protection valve, said check valve being closed when an air pressure on said reservoir side of said check valve exceeds an air pressure on a spring brake quick release valve side of said check valve, said check valve being open when an air pressure on said reservoir side of said check valve is less than an air pressure on said spring brake quick release valve side of said check valve.
In a brake system for a trailer having a supply air line connected to a reservoir by a pressure protection valve and a check valve, said reservoir being operably connected to a spring brake by a spring brake line containing a spring brake quick release valve located between said reservoir and said spring brake, the improvement comprising:
- a spring brake pressure protection valve provided in a portion of said spring brake line connecting said reservoir with said spring brake quick release valve, said spring brake pressure protection valve being maintained in a closed position until air pressure at a reservoir side of said spring brake pressure protection valve is sufficient to fully release said spring brake, said spring brake pressure protection valve being maintained in a open position when air pressure at said reservoir side thereof is sufficient to fully release said spring brake.
A brake system comprising:
- a valve assembly, including
- a valve housing having a plurality of ports therein, said ports comprising a supply air inlet, at least one spring brake outlet, at least one reservoir outlet, and a spring brake exhaust;
- said ports extending through said housing;
- a pressure protection valve in fluid communication with a passageway connected to said supply air inlet, said pressure protection valve being openable at a selected supply air pressure to connect said supply air inlet to a first check valve and to a passageway leading to said reservoir outlet;
- a spring brake quick release valve operable to open when a pressure at an upstream side thereof is sufficient to displace said spring brake quick release valve to connect said supply air inlet to be in fluid communication with said spring brake outlet, said spring brake quick release valve being operable in an exhaust mode, when a pressure at an outlet side thereof is greater than a pressure at an inlet side thereof, to connect said spring brake
- outlet with said spring brake exhaust;
- an air reservoir for containing pressurized air, said air reservoir being operably connected to said reservoir outlet;
- a spring brake chamber, for release of spring brakes by pressurization of said spring brake chamber, operably connected to said spring brake outlet;
- a control air line;
- a relay valve operably connected to said reservoir and to said control air line;
- a service brake chamber for operation of service brakes operably connected to said relay valve upon increase of control air pressure;
- and
- a spring brake pressure protection valve located in fluid communication with said reservoir and said spring brake chamber, said spring brake pressure protection valve being maintained in a closed position until air pressure at a reservoir side of said spring brake pressure protection valve is sufficient to fully release said spring brake, said spring brake pressure protection valve being maintained in an open position when air pressure at said reservoir side thereof is sufficient to fully release said spring brake.
Dependencies are inferred from the claim text.