Fluid-pressure and analogous brake systems – Multiple fluid-receiving devices – Multiple motors
Reexamination Certificate
1994-11-08
2002-10-08
Rodriguez, Pam (Department: 3683)
Fluid-pressure and analogous brake systems
Multiple fluid-receiving devices
Multiple motors
C303S002000, C303S013000
Reexamination Certificate
active
06460940
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a supplemental, vacuum-operated brake system by which the brakes of a vehicle equipped with the supplemental system, in addition to the vehicle's main brake system, can be actuated from a vacuum system without the application of foot pressure on the brake pedal. In particular, the invention relates to a system in which a vacuum-responsive servo unit mounted in the vehicle and mechanically connected to the brake pedal can be connected pneumatically to the vacuum system of a towing vehicle and controlled either by a valve located in the towing vehicle and in series with the vacuum system in the latter vehicle, or by an electric circuit controlled by a switch actuated by the brake pedal in the towing vehicle.
The term “vacuum” is used throughout the following description and claims in the sense in which it is commonly used by persons familiar with automotive brake systems as indicating a pressure much lower than atmospheric pressure although as much as several pounds per square inch higher than absolute vacuum.
When a vehicle being towed either has no brakes or has brakes that are not being operated, the towed vehicle tends to push the towing vehicle forward when the brakes of the latter are applied. This requires that the force applied to the brakes of the towing vehicle be increased, which not only wears out those brakes more rapidly than would otherwise be the case but, in extreme cases of abrupt stops, can make the connected vehicles very unstable.
Trucks that tow large semi-trailers used to haul heavy loads are equipped with air-operated brakes, as are the semi-trailers, so that the force applied to the brake pedal by the driver is greatly augmented by compressed air and applied to both the truck brakes and the trailer brakes in proportion to the driver's foot pressure on the pedal. Thus, if the driver presses hard on the brake pedal in the truck, all of brakes in both the truck and the semi-trailer will be applied forcefully, while, if the driver applies only light pressure, all of the brakes in the truck and the semi-trailer will be lightly applied. This is a full-time brake system for such vehicles and is not the sort of operation contemplated for this invention. In addition, semi-trailers do not have a separate brake system and are not driven as separate vehicles.
U.S. Pat. No. 5,031,729 to Wittkop et al shows a cement mixer being towed with its front end attached to a crane on a tow truck. The invention includes a bar that has an air cylinder extending longitudinally from one end and a piston rod extending in the same direction from the air cylinder to engage the brake pedal. At the other end of the bar is a yoke to attach that end of the bar to the steering wheel of the vehicle being towed, which prevents the steering wheel of that vehicle from turning and makes it necessary to tow it with its front wheels off the ground. An air compressor in the tow truck supplies compressed air to the cylinder under the control of the brake pedal of the tow truck to force the piston rod to press down on the brake pedal of the cement mixer and apply brake pressure to the rear wheel brakes of the latter to help stop both vehicles.
Another form of brake system is shown in U.S. Pat. No. 4,635,758 to Beard. That patent shows a motor home towing a small car. While the vehicle being towed has all four of its wheels on the ground, the motor home has a second master cylinder to transmit hydraulic pressure from the motor home to the hydraulic system of the car. The brakes of the car are not vacuum-actuated.
U.S. Pat. No. 4,249,643 to Yoder and U.S. Pat. No. 4,763,958 to Öbgard show brake systems involving tractor-trailer vehicles. The trailers never operate independently of the tractors and do not have their own independent brake systems.
The type of vehicle in which the supplemental brake system of this invention is to be used is one that is capable of being driven separately when it is not being towed and which, therefore, has its own main brake system with a brake pedal and brakes. In accordance with this invention, the supplemental brake system is connected to the brake pedal and, thus, to the brakes of the vehicle to apply force to the brake pedal in the absence of any other force applied directly to the brake pedal. In addition, the supplemental brake system of this invention does not interfere with the steering system. Therefore, all of the wheels of the vehicle can be on the ground when the vehicle is being towed.
Such a supplemental brake system is especially, although not exclusively, useful in a vehicle intended to be towed by a motor home or other recreational vehicle. At the end of a journey or a part thereof, the towed vehicle can be easily released so that it can be driven locally while the towing vehicle remains in one spot, either at a temporary location, such as a camp ground, or a more permanent location, such as its home base.
OBJECTS AND SUMMARY OF THE INVENTION
One object of this invention to provide a supplemental brake system separate from the main brake system of a vehicle so that braking can be effected without the necessity of having a driver apply force to the brake pedal of the vehicle.
Another object is to arrange all controls of the supplemental system and all parts connecting the supplemental system to a towing vehicle so that the manipulation and actuation of such parts can be carried out in as unambiguous and fail-safe a manner as possible whether the vehicle that has the supplemental system is connected to or is disconnected from a towing vehicle.
Still another object is to provide a vehicle with a supple-mental brake system that makes it possible to tow that vehicle without supporting the front wheels of that vehicle clear of the pavement.
Yet another object is to make it possible to tow larger vehicles more safely.
A further object is to make both the release of a towed vehicle from a towing vehicle and the reconnection to the towing vehicle easy to accomplish.
Still another object is to provide a two-vehicle system in which actuation of a supplemental brake system in the towed vehicle from the towing vehicle applies the brakes in the towed vehicle to a fixed extent that is less than the maximum amount possible.
After persons skilled in the technology of automotive brake systems have studied the following description, further objects of this invention may become apparent to them.
The supplemental brake system for a vehicle in accordance with this invention includes a vacuum-operated servo unit, such as the type of servo unit used in cruise control systems. The servo unit is rigidly mounted in the vehicle and has an evacuable chamber between a stationary wall and a movable wall, or diaphragm, resiliently pushed away from the stationary wall. Pneumatic means through which a chamber in the servo unit can be evacuated are connected to the chamber, and mechanical means connect the diaphragm to the brake pedal of the vehicle to apply braking force to the pedal in response to vacuum actuation of the servo unit. The supplemental brake system also includes valve means by which the main vacuum line of the primary brake system of the vehicle can be separated from the engine manifold of that vehicle while the supplemental brake system is being used and by which the main vacuum system and the supplemental vacuum line can be sealed from the atmosphere when the vehicle is running free.
A second vehicle to be used to tow a vehicle equipped with a supplemental brake system in accordance with this invention has a vacuum line that extends from a vacuum source, such as the intake manifold in the towing vehicle, to the rear of that vehicle to be connected to the pneumatic means of the towed vehicle to form a complete vacuum path. The towing vehicle has a control operated by the driver of that vehicle to actuate the supplemental brake system of the towed vehicle, but neither the brake system of the towing vehicle nor the primary brake system of the vehicle provided with a supplemental brake system need be modified,
LandOfFree
Supplemental brake system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Supplemental brake system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Supplemental brake system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2999861