Fluid-pressure and analogous brake systems – Multiple fluid-receiving devices – Multiple motors
Reexamination Certificate
2001-09-18
2003-12-23
Graham, Matthew C. (Department: 3613)
Fluid-pressure and analogous brake systems
Multiple fluid-receiving devices
Multiple motors
C188S11200R
Reexamination Certificate
active
06666527
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Not Applicable
REFERENCE TO MICROFICHE APPENDIX
Not Applicable
FIELD OF THE INVENTION
The present invention generally relates to a vehicle brake system and, more particularly, to a hydraulic brake system for a trailer which operates in cooperation with a brake system of a tow vehicle.
BACKGROUND OF THE INVENTION
Tow vehicle/trailer brake systems have long presented certain problems. The tow vehicle is often not equipped with air brake systems and therefore the trailer cannot be provided with air brakes powered by the tow vehicle air brake system. To provide the trailer with a self powered air brake system is expensive. Even when the tow vehicle is provided with an air brake system, there must be air hose connections between the tow vehicle and the trailer which are inconvenient. One solution has been to provide electric trailer brake systems. In these electric brake systems, however, the braking force is often inadequate because it is limited by the size of the magnetic armature in the brake. Also, electric brake systems are maintenance intensive. Another solution has been to provide the tow vehicle with a hydraulic system capable of operating brakes of both the tow vehicle and the trailer. With these hydraulic brake systems, however, there must be hydraulic hose connections between the tow vehicle and the trailer which are inconvenient. A further solution has been to provide the trailer with its own hydraulic circuit. These hydraulic brake systems, however, have been complicated, unreliable, and expensive. Accordingly, there is a need in the art for an improved trailer brake system.
SUMMARY OF THE INVENTION
The present invention provides a trailer brake system which overcomes at least some of the above-noted problems of the related art. According to the present invention, a trailer brake system includes, in combination, a control sensor adapted to provide a signal when the braking system of the tow vehicle is actuated, at least one brake actuated by pressurized brake fluid, a brake fluid reservoir, a brake fluid pump connected to the brake fluid reservoir, a first valve connected to the brake fluid pump and directly connected to the at least one brake, and a second valve connecting the at least one brake and the brake fluid reservoir. A controller is in communication with the control sensor, the first valve, and the second valve and is adapted to open the first valve to increase braking force applied to the at least one brake and to open the second valve to decrease braking force to the at least one brake. A feedback sensor is in communication with the controller and is capable of generating a signal that represents braking force applied to the at least one brake.
According to another aspect of the present invention, a trailer brake system includes, in combination a control sensor adapted to provide a signal when the braking system of the tow vehicle is actuated, at least one brake actuated by pressurized brake fluid, a source of pressurized brake fluid, a first valve connected to the source of pressurized brake fluid and directly connected to the at least one brake, a brake fluid reservoir, and a second valve connecting the at least one brake and the brake fluid reservoir. A controller is in communication with the control sensor, the first valve, and the second valve and is adapted to open the first valve to increase braking force applied to the at least one brake and to open the second valve to decrease braking force to the at least one brake. A feedback sensor is in communication with the controller and is capable of generating a signal that represents braking force applied to the at least one brake.
According to yet another aspect of the present invention, a trailer brake system includes, in combination, a control sensor adapted to provide a signal when the braking system of the tow vehicle is actuated, at least one brake actuated by pressurized brake fluid, a brake fluid reservoir, a brake fluid pump connected to the brake fluid reservoir, and a first solenoid valve connected to the brake fluid pump and directly connected to the at least one brake. An accumulator is adapted to hold pressurized brake fluid and is connected to the first solenoid valve to provide pressurized brake fluid thereto and to the brake fluid pump to receive brake fluid therefrom. A second solenoid valve connects the at least one brake and the brake fluid reservoir. A controller in communication with the control sensor, the first solenoid valve, and the second solenoid valve is adapted to open the first solenoid valve to increase braking force applied to the at least one brake and to open the second solenoid valve to decrease braking force to the at least one brake. A feedback sensor in communication with the controller is capable of generating a signal that represents braking force applied to the at least one brake. The controller is adapted to automatically provide a predetermined braking force to the at least one brake by opening and closing the first and second solenoid valves when the controller receives a signal from the control sensor indicating the braking system of the tow vehicle is actuated.
From the foregoing disclosure and the following more detailed description of various preferred embodiments it will be apparent to those skilled in the art that the present invention provides a significant advance in the technology and art of trailer brake systems. Particularly significant in this regard is the potential the invention affords for providing a high quality, reliable, low cost assembly. Additional features and advantages of various preferred embodiments will be better understood in view of the detailed description provided below.
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Gill George Patrick
Swanson David Leonard
Dura Global Technologies Inc.
Graham Matthew C.
Kiczek Casimir R.
Mescher Richard M.
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