Metal working – Means to assemble or disassemble – With work-holder for assembly
Reexamination Certificate
2001-05-24
2003-05-27
Bryant, David P. (Department: 3726)
Metal working
Means to assemble or disassemble
With work-holder for assembly
C029S890121, C029S402080, C269S043000, C269S069000, C269S007000, C269S909000
Reexamination Certificate
active
06568059
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a tool and a method for replacing brake system components for automotive vehicles. Specifically, the present invention relates to a tool and a method for achieving proper orientation and alignment of fittings when installed on a replacement treadle valve so that the fittings align and couple with multiple tubing connections on the vehicle upon installation of the replacement treadle valve.
BACKGROUND OF THE RELATED ART
Automotive braking systems, especially the type commonly used on trucks and heavy equipment, often use pressurized air or hydraulic fluid as a working fluid. Some braking systems provide a centralized source of pressurized air connected through tubing to two or more brake cylinders, usually one brake cylinder located at each wheel of the vehicle. Each brake cylinder is adapted to receive air pressure from the centralized source and apply it to actuate the brake cylinder thereby resisting or stopping rotation of the adjacent wheel. A treadle valve, or “foot valve”, is operated by application of force to a brake pedal that is coupled to and operates the treadle valve to controllably distribute air pressure from the centralized source to each brake cylinder. The treadle valve has a mounting flange to facilitate securing the treadle valve to the vehicle. Each brake cylinder is usually biased toward its original, disengaged position by a return spring or an opposing return cylinder for returning the brake cylinder to its original disengaged position after the brake pedal is released. The distribution of air pressure from the centralized source to the treadle valve, and from the treadle valve to the brake cylinders, is accomplished using tubing with threaded, airtight couplings at the treadle valve, centralized source and brake cylinders. Tubing may be made of metal, nylon, plastic, rubber or other materials that are well suited for supplying or delivering pressurized air because it can be shaped, bent and manipulated to conform to available surfaces of the vehicle, it is strong, relatively inexpensive and corrosion resistant. Treadle valves usually receive air from the centralized source through multiple air supply lines of tubing and distribute air to brake cylinders through multiple delivery lines of tubing.
The use of tubing to route air pressure from the centralized source to the treadle valve and distribute on to the brake cylinders also has its disadvantages. Many types of tubing used for delivering pressurized air are not very flexible and may easily kink or collapse if overstressed while bending. When the lengths of tubing and the treadle valve with fittings are originally installed, the lengths of tubing are coupled to the treadle valve and bent and aligned as necessary to allow proper make-up of the the fittings threadably inserted into the treadle valve to the tubing. Once installed, anchored to the vehicle frame or chassis and threadably coupled at its ends to the brake cylinder and the treadle valve, a length of tubing becomes very difficult to bend, redirect or manipulate during removal or replacement of the treadle valve. This problem is compounded by the use of pressure fittings or “elbows” that are used to couple the ends of the tubing to the treadle valve. Each fitting has a threaded male end for coupling to threaded ports in the treadle valve body, and a threaded female port, usually at a 90-degree angle with the threaded male end, for receiving the seal nut on the end of the length of tubing. In addition to the angle of the fitting itself, the angular orientation of the female port of the fitting, and consequently that of the mating end of the tubing, depends on how far the threaded male end of the fitting is threaded into the port in the treadle valve body. When a worn or defective treadle valve requires replacement, the defective treadle valve is unbolted at its mounting flange from its fixed location near the brake pedal, and the ends of the lengths of tubing are disconnected from the fittings in the treadle valve body by reversing the threaded male seal nuts out of the threaded female ports in the fittings. After removal of the worn or defective treadle valve with fittings still intact, the fittings must each be removed from the worn or defective treadle valve body and each fitting, or new fitting, must then be threaded into the replacement treadle valve body prior to its installation on the vehicle. Since the inflexible tubing is difficult to bend and manipulate, replacement of a worn or defective treadle valve becomes problematic. In order to minimize bending and manipulation of tubing, it is important that each fitting be threaded into the replacement treadle valve body so that it provides the same position and angular orientation for receiving the threaded male seal nut as it previously had on the worn or defective treadle valve that is replaced. After the treadle valve is decoupled from up to eight or more lengths of tubing (e.g., four providing air pressure from the centralized source to the treadle valve and four providing air pressure from the treadle valve to the brake cylinders upon braking), great care must be taken in removing the fittings from the worn or defective treadle valve and installing them or their replacements in their corresponding coupled positions relative to the replacement treadle valve. If the threaded male end of each fitting is not threaded into its port in the treadle valve body to achieve its prior angular orientation, an attempt to bend and align the end of the tubing with the fitting after installation of the replacement treadle valve may result in tubing kinks or collapse, requiring costly and time-consuming replacement of the tubing.
There is a need for a tool that facilitates the replacement of the treadle valve with each fitting threaded into the corresponding port of the replacement treadle valve in exactly the same orientation and alignment as they previously had on the worn or defective treadle valve. There is a further need for a tool that facilitates proper orientation and alignment of fittings installed on a replacement treadle valve in order to prevent damage during coupling to tubing upon installation of the treadle valve. There is a need for a tool that enables the user to properly orient and align fittings on a replacement treadle valve in their permanent positions before the replacement treadle valve is installed on the vehicle. There is a need for a method of removing a fitting from a worn or defective treadle valve and installing it in its previous orientation and alignment on the replacement treadle valve. This tool may be used with a gauge that measures angular orientation of each fitting before the fitting is removed from the worn or defective treadle valve that is being replaced so that the fitting can be oriented and aligned in the same position when it is subsequently installed on the replacement treadle valve before the replacement treadle valve is installed on the vehicle. It is desirable that the tool of the present invention be easily used by mechanics with equipment commonly found in repair shops. It is also desirable that such a tool be designed for use with a common bench vise.
It is desirable that the tool be ergonomically designed to facilitate easy removal of the fittings from the worn or defective treadle valve and easy installation with proper orientation and alignment on the replacement treadle valve. It is desirable that the tool of the present invention be designed so that the worn or defective treadle valve and the replacement treadle valve can be mounted on the tool side by side to facilitate transfer of fittings from the worn or defective treadle valve to the replacement treadle valve, and to ensure that fittings of differing configurations are properly transferred to installed in the corresponding port of the replacement treadle valve. It is desirable that the tool of the present invention allows both the worn or defective treadle valve and the replacement treadle valve to generally be rotated about their centra
Bryant David P.
Steele Patrick K.
Streets & Steele
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