Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – In vehicle wiring
Reexamination Certificate
1999-07-23
2001-11-27
Metjahic, Safet (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
In vehicle wiring
Reexamination Certificate
active
06323651
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a diagnostic device for cargo trailers and, more particularly, to a device for testing both electrical circuits and braking systems of a cargo trailer.
BACKGROUND OF THE INVENTION
Cargo hauling trailers drawn by over the road tractors are equipped with many signaling and safety features. Illuminated signaling lamps include brake lights, turn signals, and running lights. Safety features also include pneumatic braking systems, including primary braking and emergency braking systems. Trailers must be periodically inspected for proper operation of these signaling and braking systems. Breaks in the electrical wiring or in the pneumatic hoses are common problems which arise. Corrosion of electrical connections or of braking system components are also frequently encountered.
One way of testing and observing these systems is to connect a towing vehicle, such as a tractor trailer, to the trailer. A tractor has the voltage and pneumatic sources for operating the systems. An observer can activate the various systems individually, and then observe the results. This method can be quite inefficient, since it relies upon the presence of an unused tractor and also requires time to make connections and carry out the cumbersome processes of manually activating each system, before then walking around the trailer to verify proper performance.
A number of patents concerned with monitoring and testing systems for vehicles, including cargo trailers and attached tractors are known. DiLullo et al., in U.S. Pat. Nos. 4,897,642 and 5,025,253, describe a system and method for remotely monitoring the status and location of multiple part vehicles using satellite communications. In U.S. Pat. No. 5,142,278, Moallemi et al. disclose an apparatus and method for communication between a tractor and trailer via existing truck wiring, and transmitting the status to a remote receiver. Gee et al., in U.S. Pat. Nos. 5,397,924 and 5,693,985, describe a truck tractor and trailer communication system that uses a standard seven pin connector where high speed data communication links are employed for control and diagnostics of the electrical system. In U.S. Pat. No. 5,488,352, Jasper discloses a communications channel that interconnects controllers located in a tractor and a trailer unit. The controllers monitor and control various subsystems of the tractor/trailer combination.
An apparatus and method for performing diagnostic tests on the electrical systems of recreational vehicles is disclosed by Hammerly in U.S. Pat. No. 5,086,277. The device contains switches and LEDs plus a voltmeter and an ammeter for use in testing the circuits. A simple trailer lamp testing and lamp storage apparatus is described by Doland, Sr., et al. in U.S. Pat. No. 5,416,421. Walkington et al., in U.S. Pat. No. 5,604,439, disclose a tractor/trailer lamp circuit continuity test device with LEDs to indicate if the lamps are operating. Gutierrez, in U.S. Pat. No. 5,602,482, discloses a trailer system tester that includes a portable diagnostic device for checking electrical signaling systems for trailers. Also included on the device is a pneumatic system to pressurize the air breaks of the trailer for leak testing. The use of vacuum or hydraulic breaks is also mentioned.
Thus, there is an unmet need for a device that will allow an individual to test both the electrical circuits and the pneumatic braking systems of a cargo trailer, as well as assist the individual in locating trouble spots in any of these systems.
SUMMARY OF THE INVENTION
The invention is a device for testing the electrical circuitry on all trailers used in the cargo industry. The device plugs into the electrical connector of a trailer and allows a single mechanic to test and make break adjustments without the assistance of another individual, to check the operation of all lighting and signal lights of the trailer, and to test the integrity of each electrical circuit and locate shorts in the circuits.
The electrical and pneumatic diagnostic device comprises a housing member enclosing an electrical circuitry for testing the electrical and pneumatic systems of cargo hauling trailers. A power supply means is connectable to the electrical circuitry for supplying nominal 12 volt direct current thereto. A first set of sub-circuits is contained in the electrical circuitry, with each sub-circuit serving a selected illumination and signaling lighting circuit of the trailer. A second set of sub-circuits is contained in the electrical circuitry, with these sub-circuits serving the pneumatic system of the trailer. A means for connecting the first and second sets of sub-circuits to the electrical system of the trailer is present. A switch means is present for selectively powering the first set or the second set of sub-circuits. The first set of sub-circuits each has a control switch means for powering a corresponding trailer electrical circuit, and each sub-circuit has a visual indicator means for denoting sub-circuit power. There is a conduit with a valve for supplying compressed air to a sealed conduit in the housing, with first and second fittings on the sealed conduit for connection to the service and emergency hoses of the cargo trailer braking system. The second set of sub-circuits contains a timer means for periodically actuating the valve that actuates the cargo trailer braking system at a selected time interval.
Any electrical short in a circuit is located by applying a low amperage current, at 12 volts, to the inoperative circuit and locating the warm point in the wiring where the short exists. The break system adjustments provided by the device include checking sticky or frozen cams, moving the cams while lubricating them, and testing the various valve functions in the air breaks system of the cargo trailer.
REFERENCES:
patent: 4771387 (1988-09-01), Hexel et al.
patent: 4897642 (1990-01-01), Dilullo et al.
patent: 5025253 (1991-06-01), Dilullo et al.
patent: 5086277 (1992-02-01), Hammerly
patent: 5142278 (1992-08-01), Moallemi et al.
patent: 5397924 (1995-03-01), Gee et al.
patent: 5416421 (1995-05-01), Doland, Sr. et al.
patent: 5488352 (1996-01-01), Jasper
patent: 5488859 (1996-02-01), Britt
patent: 5602482 (1997-02-01), Gutierrez
patent: 5604439 (1997-02-01), Walkington et al.
patent: 5693985 (1997-12-01), Gee et al.
LeRoux Etienne P
Metjahic Safet
Randall Tipton A.
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