1. Field of the invention
The present invention relates to a wiring apparatus for use in wiring automotive electrical circuits which apparatus has an improved connection-mechanism between a basic-circuit block having basic circuits common to all types of models and classes of the automobiles and option-circuit blocks having optional circuits specific to individual models and classes of the automobiles.
2. Prior Art
A connection block has been commonly used for eliminating many multi-branch wirings existing in a wire harness to simplify wiring. Such a connection block generally incorporates many relays, fuses, and branch circuits consisting of a plurality of bus bars in a housing, and is connected through connectors to the wire harness from various loads and a variety of electrical components in the automobile.
Complexity of circuits within the connection blocks, however, depends on models, classes, and manufacturers of the vehicles, and may be expected to be changed when mounting additional electrical components to the vehicles later on. Thus a problem arises in wiring the automobile electrical circuits to provide and administer a wide variety of connection blocks.
In order to overcome this problem, the Applicant has proposed in Japanese Patent KOKAI publications No. 55-47931 a wiring method wherein the wiring apparatus consists of a basic block having basic circuits that can be incorporated in all types of cars regardless of their models and classes etc., and a block on which optional circuits can be selectively constructed in accordance with the models and classes of the vehicles thus providing general applicability by suitably combining these two blocks.
That is, in FIG. 4, an connection block a having basic circuits and a connection block b having optional circuits are connected to each other through a dovetail joint i.e., a groove and a plug inserted thereinto. Both blocks are provided with a plurality of fuses f and relays r. Many connectors C1, C2, C3 . . . are provided on the connection block a and wire harness WO, Wo'. . . are provided on the connection block b. Electrical connection between the connection block a and the connection block b is made by, for example, fitting the connector C1', on which the harness WO' is assembled, into the aforementioned connector C1.
The prior art wiring method having the connection block a inserted into the connection block b suffers from a drawback in that a two-step fitting procedure is required, one for fitting the two blocks through a dovetail joint and the other for fitting the connector C1' into C1. In this method the wire harness must have a sufficient play in its length for connector-fitting and connecting the two blocks in side by side relation through a dovetail joint requires a wide mounting space.