Electrical connection box

Abstract: An electrical connection box containing at least one generally planar base insulative plate having two flat surfaces. There is at least one busbar on or adjacent the first surface which is capable of electrical contact with a plurality of insulated wires. The busbar has one or more pressure connection sections which include a pair of blades which cut through the insulation on the wires and make electrical contact therewith. The insulated wires are straight, parallel to each other, and are located in the wire concentration section which is on or adjacent the second surface of the base insulative plate. The wire concentration section and the pressure connection section are in register with each other and openings are provided in the base insulative plate through which the blades can project. Thus, when pressure is exerted on the blades or on the insulated wires, the blades cut through the insulation on the wires, forming an electrical contact between the busbar and the wires in a single operation. It is unnecessary to insert the wires one at a time. This provides increased ease of assembly, reduces costs, and provides secure and reliable connections.

Description: The present Invention is directed to an electrical connection box, particularly designed for use in automobiles. More specifically, it provides a high-density branching circuit wherein the wire connection section is on a busbar stacked on an insulative plate and the wire serves as an intermediate connection, thereby increasing the wire efficiency of the busbar. Preferably, the elements are within the electrical connection box. The Invention will be described with relation to an automobile, but its use is not limited thereto. BACKGROUND OF THE INVENTION In recent years, the number and diversity of electronic parts to be installed in automobiles has increased rapidly. As a result, the circuits contained in automotive electrical connection boxes have also been increased. In an attempt to form high density branch circuits, busbars and pressure-connections between the wire and the terminal have been used. As shown particularly in Figure 3, busbars 7 and 8 are to be connected to each other. However, busbar 9 is located between them. In order to avoid electrical contact between busbars 7 and 8 and busbar 9, wire 6 is pressed between blades 11, thereby avoiding busbar 9 and securing the electrical connection between busbars 7 and 8. As shown in Figure 4, insulative plate 4D carries busbars 7 and 8. Connection sections 10 pass through openings 17 in insulative plate 4E and blades 11 cut through the insulation on wires 6 to make electrical contact with the cores thereof. A further modification is shown in Figure 5, wherein insulative plate 4C carries busbar 9 and insulative plate 4D carries busbars 7 and 8. Connection section 10 of busbar 9 passes through opening 17 in insulative plate 4D and through opening 17 in insulative plate 4E. Since busbars 7 and 8 are resting on insulative plate 4D, connection sections 10 thereof only have to pass through openings 17 in insulation plate 4E. However, since busbar 9 rests on insulative plate 4C, section 10 passes through openings 17 in plates 4D and 4E. However, the busbar method is such that an increased number of circuits in the connection box is accompanied by a decrease in the number of circuits'which can be placed on a single layer. Thus, a greater number of layers must be provided, thereby making the connection box larger and more complex. On the other hand, if pressure-connection methods are used, the circuit density is increased and design changes can be readily implemented; however, greater equipment costs result. In some cases, the two methods are combined. In such structures, busbar layers are stacked with layers formed from wires and pressure-, connection terminals. These layers are connected to external circuits. However, this combined method results in higher production costs, creating problems in manufacture of low cost automobiles. In US 4 950 168 A an electrical connection base according to the preamble of claim 1 is disclosed. It can be reparated into a plurality of reparately formed connection blocks each having terminals in which a plurality of conductors are press-fitted. SUMMARY OF THE INVENTION It is an object of the present Invention to provide a simple structure for the internal circuits in an electrical connection box, while permitting these circuits to be arranged in a highly dense configuration. It is also an object of the present Invention to provide such circuitry wherein the wires can be pressure-connected to the busbars at one time, the circuits can easily be changed and which results in a low-cost connection box suitable for mass production of inexpensive automobiles. There and other objects of the present invention are achieved by an electrical connection base according to claim 1. The dependent claims treat further developements of the present invention. In practicing the present Invention, there is provided an electrical connection box containing at least one generally planar base insulative plate. There is at least one busbar on or adjacent the first surface of the insulative plate which can electrically contact a first plurality of insulated wires. For this purpose, the busbar has one or more pressure connection sections, each of which includes a pair of blades which cut through the insulation on the wires to make electrical contact with the core thereof. There is a plurality of openings extending through the base insulative plates in line with the points on the wires at which electrical. contacts are desired. The busbars are bent so that they are in alignment with the predetermined points and the plurality of openings giving access thereto. The bent portions of the busbars form connection sections which, when the box is assembled, extend through the openings and terminate in contact blades. The blades are adapted to receive the insulated wires; when the wires are pressed therein, the blades cut through the insulation and make electrical contact with the wire core. The insulated wires are straight, parallel to each other, and located in a wire concentration section on or adjacent the second surface of the base insulative plates. The wire concentration section is in register with the pressure connection section. Thus, since the wires are suitably aligned and closely adjacent each other, the various blades can engage the wires and make electrical contact therewith by means of a single application of pressure. Thus, all of the wires are connected at one time and it is not necessary to insert each wire individually. Preferably, all of the wires should be of the same length so that they can be easily placed in the wire concentration section. After the circuits have been formed by making the desired electrical contacts, unneeded portions of the wires are cut away and removed, thereby simplifying the final product. In order to retain the wires on the insulative plates, pairs of wire guides are provided. These constitute protuberances extending from the second surface of the insulative plates and are spaced apart transversely to the axes of the wires by a distance which does not exceed the diameter of an individual wire. Preferably, the distance should be slightly less than the wire diameter. Some of the connection sections may extend, not only through an opening in the base insulative plate, but also through further opening(s) in one or more additional insulative plates, thereby making contact with the plurality of wires on one of the additional insulative plates. It is also within the scope of the present Invention to provide a second plurality of insulated wires which are also straight and located within the wire concentration section. They are parallel for most of their length but cross over each other at a particular point. At least one pair of blades contacts this point under pressure to form the electrical contact with the wires. Here, too, it is advantageous if the wires are all of the same length. In view of the complexity of the electrical systems of automobiles, a preferred form of the Invention consists of a plurality of interleaved insulative plates. These stacked plates carry either the busbar(s), the wires, or both. In a modification of the Invention, the busbars may be spaced from the wires to which they are to be connected by one or more insulative plates. In such cases, the openings are aligned with one another and with the point at which the connections between the wires and the busbars are desired. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, constituting a part hereof, and in which like reference characters indicate like parts, Figure 1 is an exploded perspective view of the connection box according to the present Invention; Figure 2(A) is a plan view of an insulative plate having a wire concentration section; Figure 2(B) is a view, similar to that of Figure 2(A) showing the underside of the insulative plate; Figure 3 is an exploded perspective view of the formation of the pressure-connection between the busbar and one of the wires according to the prior art; Figure 4 is a cross section of a wire providing an intermediate connection for busbars on the same level according to the prior art; Figure 5 is a view, similar to that of Figure 4, wherein the connections for the busbars are on different levels according to the prior art; and Figure 6 is a schematic view showing the wires parallel to each other and indicating the unused portions which are to be cut off. DETAILED-DESCRIPTION OF THE INVENTION As shown in Figures 1 and 2, connection box 1 comprises upper case 2 and lower case 3. Within the box are alternated insulator plates 4A, 4B, 4C, 4D, and 4E and busbars 5A, 5B, 5C, and 5D. Wires 6A and 6B are located in wire concentration sections 15. Wires 6a, 6b, 6c, 6d, 6e, 6f, and 6g are retained on the second surface of (for example) insulative plate 4E by wire guides 16. Openings 17, through which connection sections 10 project to make contact with the wires, extend through insulative plate 4E. On the first surface of insulative plate 4E, openings 17 are provided at the predetermined contact points. Connection sections. 10 terminate in blades 11 which are adapted to receive wires 6 and cut through the insulation thereon to make contact with the electrically conductive wire cores. Referring more specifically to Figure 6, blades 11 on connection sections 10 are in electrical contact with wires 6. Unused sections 12 (cross hatched) are cut away in order to minimize the bulk of the finished connector box. In a preferred form of the Invention, as best shown in Figure 1, a second plurality of wires 6B is located adjacent wire concentration section 15. In particular, these wires are parallel to each other throughout most of their length, but are provided with cross over point 6a where the wires come together. Thus, if a connection is to be made to such wires, contact can be carried out quite readily. Furthermore, the circuits can be modified simply by adding or removing connections with the wires. Furthermore, the wires used for intermediate connections for the busbars can be concentrated in the wire concentration section and preferably arranged in straight lines parallel to each other. This makes the wiring easier and the equipment necessary is readily available. Thus, the device of the present Invention is well suited for mass production and low assembly costs. While only a limited number of specific embodiments has been expressly disclosed, it is, nonetheless, to be broadly construed, and not to be limited. The scope of the invention is only limited by of the claims appended hereto.

Claims: An electrical connection box (1) containing at least one generally planar base insulative plate (4A, 4B, 4C, 4D, 4E) having a first surface, at least one busbar (5A, 5B, 5C, 5D) on or adjacent said first surface adapted to electrically contact a first plurality (6A) of insulated wires, said busbar (5A, 5B, 5C, 5D) having at least one pressure connection section (1 0) which includes a pair of blades (11) adapted to make electrical contact with at least one of said insulated wires, said insulated wires being straight, parallel to each other, and located in a wire concentration section (15) on or adjacent a second surface of said base insulative plate (4A, 4B, 4C,4D, 4E), said second surface being opposite said first surface, said wire concentration section (15) being in register with said pressure connection section (10), openings (17) in said base insulative plate (4A, 4B, 4C,4D, 4E) through which said blades (10) project, whereby pressure exerted on said busbar (5A, 5B, 5C, 5D) or said insulated wires forms electrical contacts between said busbar (5A, 5B, 5C, 5D) and said plurality (6A) of wires in a single peration characterised by wire retainers (16) securing said first plurality of wires to said insulative plate, extending from the second surface of said insulative plate (4A, 4E) each comprising a pair of protuberances, wherein said protuberances are spaced apart in a direction transverse to a longitudinal axis of one of said first plurality (6A) of wires by a distance not greater than a diameter of said wires, said busbars (5A, 5B, 5C, 5D) being bent so that the bent portions of the busbars (5A, 5B, 5C, 5D) form said pressure connection sections (10). The electrical connection box (1) of Claim 1, wherein each of said first plurality (6A) of wires, when placed in said wire connection section (15), is of substantially the same length. The electrical connection box (1) of Claim 2, wherein, after said electrical contacts have been made, unneeded sections (12) of said first plurality (6A) of wires are removed. The electrical connection box (1) of Claim 1, wherein there is at least one additional interleaved insulative plate (4B, 4C, 4D) carrying said busbar (5A, 5B, 5C, 5D) and/or said first plurality (6A) of wires. The electrical connection box (1) of Claim 1, comprising a second plurality (6B) of insulated wires which are straight, parallel to each other through most of their length, and located in said wire concentration section (15) adjacent said first plurality (6A) of wires, said second plurality (6B) of wires having a point at which said wires cross each other, at least one said pair of blades (11) forming said electrical contact with said wires at said point. The electrical connection box (1) of Claim 5, wherein each of said second plurality (6B) of wires, when placed in said wire connection section (15), are of substantially the same length. The electrical connection box (1) of Claim 4, wherein at least one of said pressure connection sections (10) extends through an opening in said additional insulative plate (4B, 4C, 4D), thereby making electrical contact with said first plurality (6A) of wires on said additional insulative plate (4B, 4C, 4D).

Inventors: KAWAKITA SHINJI, KAWAKITA, SHINJI, Kawakita, Shinji, c/o Sumitomo Wiring Systems,Ltd.
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1999
Main classification: B60R16
IPC codes: B60R16, H02G3, H05K3