Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – With provision to conduct electricity from panel circuit to...
Reexamination Certificate
2001-02-06
2004-06-22
Prasad, Chandrika (Department: 2839)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
With provision to conduct electricity from panel circuit to...
C439S067000, C439S038000
Reexamination Certificate
active
06752637
ABSTRACT:
FIELD OF THE INVENTION
The field of the present invention is that of flexible circuits. More particularly the field of the present invention is that of flexible circuits utilized in the automotive industry which can additionally incorporate the terminals of surface mounted devices as contacts for various electrical components.
BACKGROUND OF THE INVENTION
In the most recent quarter century there has been a significant increase in the utilization of electronics in automotive vehicles. For example virtually all automotive vehicles are now controlled by an engine control module to optimize the performance of the engine with regard to fuel efficiency and environmental emissions. Inflatable restraints have been added to enhance occupant safety in an event of a crash situation. Advanced braking systems have been provided such as in anti-skid braking and traction control to further enhance safe operation of the vehicle occupants. Other electrical systems have been added or enhanced to add to the comfort of the vehicle. The above mentioned additions and enhancements have added to the complexity of the wiring system which supplies power and signal transfer to and from various electrical components and controllers. Currently most power requirements and signaling requirements in a vehicle are supplied by hard conductor wiring. The required wiring is provided in a bundle which is commonly called a wiring harness. Fabrication of a wiring harness is a very labor intensive operation. Additionally installation and/or repair of a wiring harness can also be very time consuming and expensive. Another disadvantage associated with the hard copper conductive wiring currently provided in most vehicles is in the cost associated with the copper. For certain applications the copper wire needed to provide for signal transfer at a low electrical load can be provided by a copper wire of a very small cross-sectional area. However, a minimum diameter of copper wiring is not determined not by its electrical requirements. The minimum diameter of the wiring is determined by its frailty during the assembly process of the wiring harness and of the wiring of the vehicle.
In an attempt to reduce the cost of automotive wiring harnesses a new type of electrical conduit has been provided. This new conduit is typically referred to as a flexible circuit. In a flexible circuit a polymeric (or insulated metallic ribbon) substrate which is flexible provides support for the various electrical conductor lines. The electrical conductors needed are then supplied by a foil which is affixed to the flexible substrate. Another flexible layer of polymeric material can cover the conductors on the flexible substrate.
The utilization of flexible circuits as a replacement for the prior wiring harnesses has been limited due to the particular problems faced by flexible circuits at the various component interfaces. For instance, the interface of the flexible circuit with a fuse box has been a particular limiting factor. To overcome those limitations an inventive contact method has been provided as explained in U.S. patent application Ser. No. 09/298,240 filed Apr. 22, 1999. Other examples of connector interfaces for flexible circuits can be found in a review of U.S. Pat. Nos. 5,885,091 and 5,969,418, commonly assigned.
Another problem which comes about with the utilization of flexible circuits is in the use of relays. Relays are typically switches that have two contacts which are either spring biased towards or away from each other, which are activated (closed or opened) by an electromagnetic force by a selectively excitable electromagnetic coil. Relays are typically provided for high current applications which require momentary application. Relays are commonly self-contained entities that contain a coil and contacts. Relays are typically pre-packaged to a pre-determined physical footprint. The design of relays is mostly controlled by their manufacturers and users of such relays adapt their circuits to pre-designed physical specifications. Two major elements in the design of relays is the generation of high current contact heat between the contacts, and the amount of current which is allowed in the exciting coil which is typically of a much lower current. Because of the current capabilities of the contacts of the relay, most relays have a solid post with a relatively high mass. The relay coil is typically specified to be excited by a low current and therefore has very low mass copper wires. When connecting the relay to a conventional circuit board the high relative mass of the relay terminals provide a relatively large heat sink so that lots of heat is required to assemble the relay to the remainder of the circuit. This heat required for assembly is typically within the limits of a rigid circuit board. However, with a flexible circuit no such rigid circuit board is provided and items such as relays which require a high heat input are difficult to assemble to the flexible circuit. An attempt to provide the heat required for many relays will cause the flexible circuit to be warped and deformed. Prior to the present invention to accommodate the heat of assembly the flexible circuit would often have to be redesigned to be a non-planar structure with a much larger mass then what was desirable. Such a modification of the flexible circuit diminishes its many advantages. Flexibility of the flexible circuit is especially important in applications of engine control modules which often have physically large circuits which are folded over for placement within a mounting box to conserve space within the engine compartment of the vehicle. It is desirable to provide freedom of utilization of a flexible circuit which allows for the relatively higher current contacts in connecting one circuit to another that is typically required in the utilization of a relay without having a flexible circuit with an increased mass which will diminish its characteristics of flexibility.
SUMMARY OF THE INVENTION
To make manifest the above noted and other desires a revelation of the present invention is brought forth. In a preferred embodiment circuit arrangement of the present invention, the contact members of the relay are separated from the coil mechanism. The contact members are brought into contact by displacement of two flexible substrates which are normally separated from each other. The contacts of the substrates can be one of the circuit conductive traces with an end cap of a surface mounted device on the other substrate. The device which brings the separated substrates in the contact with each other can be an aforementioned coil or can be due to physical displacement such as in a keyboard. With the utilization of surface mounted devices which are already utilized on the flexible circuits the end caps of the surface mounted devices can be utilized as the contacts. The present invention is even more particularly advantageous since most end caps are made from a silver alloy conductive material which provides a low interface resistance. When used in the embodiment of a relay, the flexible circuit arrangement of the present invention can have a coil that can be post connected with one of the substrates on a ferritic carrier. The coil need not be exposed to the heat of assembly of the surface mounted devices.
Other features of the invention will become more apparent to those skilled in the art upon a reading of the following detailed description and upon reference to the drawings.
REFERENCES:
patent: 4093883 (1978-06-01), Yamamoto
patent: 4403166 (1983-09-01), Tanaka et al.
patent: 4445732 (1984-05-01), Wafer
patent: 4564832 (1986-01-01), Inoue
patent: 4918513 (1990-04-01), Kurose et al.
patent: 5121091 (1992-06-01), Fujiyama
patent: 5156553 (1992-10-01), Katsumata et al.
patent: 5161985 (1992-11-01), Ramsey
patent: 5501009 (1996-03-01), McClure
patent: 5513075 (1996-04-01), Capper et al.
patent: 5726861 (1998-03-01), Ostrem
patent: 5727956 (1998-03-01), Mitra et al.
patent: 5921787 (1999-07-01), Pope et al.
Belanger, Jr. Thomas Dudley
Rutkowski David John
Ford Global Technologies LLC
Prasad Chandrika
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