Electrical transmission or interconnection systems – Vehicle mounted systems – Automobile
Reexamination Certificate
1999-06-11
2001-07-10
Ballato, Josie (Department: 2836)
Electrical transmission or interconnection systems
Vehicle mounted systems
Automobile
C307S010100, C439S490000
Reexamination Certificate
active
06259170
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates generally to an electrical connector and, more particularly, to an electrical plug for connecting a tow vehicle electrical system wires to a trailer electrical system wires.
INVENTION BACKGROUND
Trailers configured to be towed behind automotive vehicles typically include trailer electrical systems that include lights, wiring and a trailer electrical plug. The lights are generally mounted on or near a rear portion of the trailers they are mounted on. The lights include left and right turn signal lights, and left and right taillights. Each light normally includes an incandescent lamp and a socket configured to receive the incandescent lamp. The wires extend from the light sockets to the trailer electrical plug. A standard type of plug used in such electrical systems is known as a “four-flat” trailer wiring plug and is configured to plug into a complementary vehicle electrical plug mounted on a tow vehicle. When joined together, the trailer and vehicle plugs connect tow vehicle electrical system wires to the trailer electrical system wires, which transmits power from vehicle lighting circuits to the trailer electrical system to illuminate the trailer lights.
Each trailer electrical plug typically includes four electrical connectors. One of these four connectors is connected to a chassis ground wire that connects to a chassis ground lead from each light through the trailer chassis. Another of the four connectors is connected to a wire that extends and connects to the left turn signal light. A third of the four connectors is connected to a wire that extends and connects to the right turn signal light. The remaining connector is connected to a wire that extends to both the left and right taillights.
The four connectors of the trailer plug generally include one female and three male connectors encased in a parallel disposition in a plastic jacket or casing. Similarly, the vehicle plug includes four connectors encased in a plastic jacket. However, the four connectors of the vehicle plug generally include one male and three female connectors to complement the one female and three male connectors of the trailer plug. The one female trailer plug connector and the one male vehicle plug connector are conventionally the chassis ground connection. The other three connectors are conventionally, in order from the ground connectors, the tail light connectors and the left and right turn signal light connectors. This convention insures that the correct contacts are made between taillight and turn signal light circuits whenever a trailer electrical system is connected to a tow vehicle electrical system.
Trailer electrical systems are also known to include circuit breakers. The circuit breakers are configured to open circuits that are shorted or supplied with an excessive amount of electrical current. The circuit breakers must then be reset before the circuit can be closed after a fault has been corrected. Some trailer electrical systems also include sensor lights that illuminate when a given circuit is closed and extinguish when the circuit is opened.
In the electrical arts, it is known to employ polymeric positive temperature coefficient resettable fuses (PTC devices) that use conductive-polymer technology to limit the flow of dangerously high current during fault conditions. These are solid-state devices configured to reset after a fault is cleared and power to the circuit is removed.
Also known in the electrical arts are bi-color light-emitting diodes (LED's), each of which includes two monochromatic light sources. Each monochromatic light source includes a tiny chip that generates a very narrow band of electromagnetic energy in the visible spectrum, i.e., colored light. The two chips are encased in a single epoxy lens, which may also be colored.
What is needed is a trailer electrical system circuit protection and fault indication system that is readily observable and understandable and that is self-resetting.
INVENTION SUMMARY
In accordance with this invention an electrical trailer plug device is provided that includes at least one electrical connector configured to connect an electrical current path of a vehicle electrical system to an electrical current path of a trailer electrical system to complete an electrical circuit supplying electricity from the vehicle electrical system to a lamp supported on the trailer. A circuit protection device in the form of a circuit breaker or fuse is connected in the circuit between at least one of the connectors and a lamp connected in the circuit. The circuit protection device is configured to limit current flow in the circuit when the current exceeds a predetermined value. The device includes a first sensor light and is configured to illuminate the first sensor light when current is flowing in the circuit but has not exceeded the predetermined value. The device may also include a second sensor light and be configured to illuminate the second sensor light when the circuit protection device is limiting current flow in the circuit in response to a fault in the circuit.
Other aspects of the invention include a plug device that includes three sets of connectors, circuit protection devices and lights along with a third connector serving to provide a common ground connection. The four connectors complete three electrical circuits that supply electricity from the vehicle electrical system to four trailer lamps supported on the trailer.
Other aspects of the invention also include a single bi-color light-emitting diode (LED) comprising the two sensor lights in each circuit, and the circuit protection devices comprising polymeric positive temperature coefficient (PTC) resettable fuses.
Another aspect of the invention is that the three bi-color LED's are encapsulated into a one-piece translucent cast acrylic block that is inserted as a single piece into the device. This provides simplified assembly over the installation of six separate “loose piece” LED's. This one-piece construction also promotes a superior moisture seal when the components are overmolded into a plug casing. The moisture seal is superior because only one component (the block) protrudes from the surface of the plug casing.
Other objects, features and advantages of this invention include the provision of a trailer plug that includes components that help identify trailer electrical problems such as shorts in the wiring or excessive loads, that can identify a problem in the towing vehicle electrical system, that protect the towing vehicle wiring against shorts or overloads in a trailer electrical system and that is constructed in such a way as to be resistant to moisture damage.
REFERENCES:
patent: 4057310 (1977-11-01), Young
patent: 5052951 (1991-10-01), Johnson
patent: 5442332 (1995-08-01), Hughes
patent: 5498910 (1996-03-01), Hopkins et al.
patent: 5604439 (1997-02-01), Walkington et al.
patent: 5936407 (1999-08-01), Borland
patent: 6177865 (2001-01-01), Bryant et al.
Short Stop packaging and illustration dated ©1997—plus in circuit breaker for trailer wiring.
U-haul traier wiring harness packaging dated Feb. 1996—4-way flat piggy plugs with 60′ lead.
Bryant Richard
Johnson Richard
Limoge Henry J.
Ballato Josie
Doigan Lloyd D.
Draw-Tite Inc.
Polk Sharon
Redman Leon E.
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