Electrical distribution centre

Abstract: An electrical distribution centre (10) electrically interconnects electrical and electronic devices (12-16) and electrical connectors of wiring harnesses. The electrical distribution centre (10) comprises a main bus plate (28) that includes a plurality of stamped metal circuit components (34,34a) insert moulded in an insulation board (36). The stamped metal circuit components (34,34a) have a plurality of male blade terminals (38,38a) which project outwardly of the insulation board (36) and which include wire receiving slots (40). The main bus plate (28) is sandwiched between upper and lower bus plates (30,32) each including a plurality of wire circuit components (52) in an insulated routing board (44) having slots extending through it. The male blade terminals (38,38a) of the main bus plate (28) project through the slots (40) of the upper and lower bus plates (30,32) for connection with the electrical and electronic components (12-16) and the electrical connectors of the wiring harnesses. The wire receiving slots (40) of selected male blade terminals (38,38a) receive the wire circuit components (52) of the upper and lower bus plates (30,32) as the selected male blade terminals (38,38a) pass through the slots (40) to provide a bus between various male blade terminals (38,38a).

Description: This invention relates to an electrical distribution centre, for example to an electrical distribution centre which uses bus plates for interconnecting terminals which are mated to electrical or electronic devices or electrical connectors of wiring harnesses. US-A-5,023,752 discloses an electrical distribution centre for automotive use. This electrical distribution centre utilizes stamped metal circuit components to conduct current through internal circuitry. It involves multiple layers of stamped metal circuit components heat-staked into corresponding tracks of thermoplastics insulator plates. These plate assemblies are stacked and secured together in a unit handled bussing sub-assembly. The stamped metal circuit components include male blade terminals passing through slots of the insulator plates and projecting outwardly of the sub-assembly to mate to electrical connectors of wiring harnesses or to electrical and electronic devices via double-ended female terminals. The bussing sub-assembly is disposed and secured within a two-piece thermoplastic housing having plug-in portions for receiving the electrical connectors of the wiring harnesses and the electrical and electronic devices. While this electrical distribution centre has been successfully used by General Motors Corporation in its Saturn automotive vehicles, it has a significant drawback in that changes in the internal circuitry are expensive due largely to the inflexibility of the stamped metal circuit components. Each stamped metal circuit component is produced from a unique stamping die and a unique mould die is used to produce each insulator plate with the corresponding circuit tracks. As a result, any change in circuit configuration, regardless of how minor, forces tool revisions for the stampings and insulator plates. This is not only costly but also requires long lead times for the tool revisions. Moreover, completely new tooling may be required if significant changes are involved. It is also known from US-A-4,684,765 and from junction blocks produced by the Packard Electric Division of General Motors Corporation to provide a junction block comprising double-ended male blade terminals which are insert moulded into a housing plate and upper and lower bussing plates each comprising a routing board and solid core copper wire routed onto the routing board. Each end of the male blade terminals projects outwardly of the housing plate and has a wire-receiving slot of the insulation displacement-type near the base of its blade. The upper and lower bussing plates are assembled to the housing plate by pressing the upper and lower bussing plates over the projecting ends of the male blade terminals. This action forces the solid core wire into wire receiving slots creating bussing circuits between the male blade terminals. When electrical female connectors of wiring harnesses are mated to each side of the junction block, the routed wires provide for bussing between the various wiring harnesses. As indicated in US-A-4,684,765 the routing of the wire onto the routing boards is an automatic process which can quickly be reprogrammed to create any configuration of wire routing. Thus, bussing circuit configurations are easy to create and change with minimal cost and time. This routed wire technology provides flexibility in bussing. However, it too has a major drawback in that the present routed wire technology has a relatively low current carrying capability and consequently it is not suitable for use in automotive applications such as electrical distribution centres which require relatively high current carrying capability for many of its circuits. The present invention seeks to provide an improved electrical distribution centre. According to an aspect of the present invention, there is provided an electrical distribution centre as specified in claim 1. Preferably, the electrical distribution centre is suitable for automotive use and has flexibility in creating and changing circuit configurations between the electrical and electronic devices and the electrical connectors of wiring harnesses plugged into the electrical distribution centre as well as a relatively high current capability required for many automotive circuits. An embodiment of the present invention is described below, by way of illustration only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an embodiment of electrical distribution centre in which a cover thereof is shown in a raised position to illustrate components plugged into the distribution centre; Figure 2 is an exploded perspective view of the electrical distribution centre of Figure 1; Figure 3 is an enlarged view of a corner portion of the electrical distribution centre of Figure 2; Figure 4 is a cross-sectional view of the electrical distribution centre of Figure 1 taken substantially along line 4-4 of Figure 2; Figure 5 is a cross-sectional view of the electrical distribution centre of Figure 1 taken substantially along line 5-5 of Figure 2; Figure 6 is a cross-sectional view of the electrical distribution centre of Figure 1 taken substantially along line 6-6 of Figure 5; and Figure 7 is a fragmentary view of a portion of a second embodiment of electrical distribution centre. Referring to Figure 1, an electrical distribution centre 10 provides electrical interconnections between electrical and electronic devices, such as mini-fuses 12, maxi-fuses 14 and relays 16 plugged into the top of the electrical distribution centre 10 and electrical connectors of wiring harnesses (not shown) plugged into a plurality of connector sockets 18 in the bottom of the electrical distribution centre 10. The electrical distribution centre 10 includes a housing 20 and cover 22 moulded from a thermoplastics electrically insulating material. The housing 20 comprises a lower housing 24 and an upper housing 26. The connector sockets 18 for receiving the electrical connectors of wiring harnesses (not shown) are moulded as an integral part of the lower housing 24. The mini-fuses 12, maxi-fuses 14 and relay 16 are plugged into terminal cavities in the upper housing 24 and held in place by the cover 22 when it is attached to the housing 20. This feature is explained in US-A-5,023,752. The electrical distribution centre 10 comprises several components disposed within the housing 20, as shown in Figures 2 to 6. These include a main bus plate 28 sandwiched between upper and lower bus plates 30 and 32. The main bus plate 28 comprises a plurality of stamped metal circuit components 34 and 34a and an insulation board 36 of moulded thermoplastics material for fixing the stamped metal circuit components 34 and 34a in a predetermined pattern. Two different general types of stamped metal circuit components 34, 34a are used, each type including male blade terminals 38 and/or 38a which protrude from the insulation board 36. One general type of stamped metal circuit component comprises a flat planar body interconnecting a plurality of male blade terminals 38 and/or 38a perpendicularly attached at the edges of the body. These male blade terminals 38 and/or 38a may be bent upwardly in the drawings (that is, towards the cover 22) to protrude above the insulation board 36 or bent downwardly (that is, away from the cover 22) to protrude below the insulation board 36. Moreover, the male blade terminals 38 and/or 38a may extend in the same or in opposite directions, the stamped metal circuit components 34 and 34a including either U-shaped portions or Z-shaped portions when viewed on end. Another general type of stamped circuit component 34 comprises a series of male blade terminals 38 or 38a connected by a carrier strip coplanar with the male blade terminals 38 or 38a. This latter type includes variants such as a single pair of oppositely extending male blade terminals, several pairs of such terminals strung together by a carrier strip and several male blade terminals strung together, where some are double-ended male blade terminals and some are single-ended male blade terminals extending in one direction or another. In any event, the main bus plate 28 comprises one or more stamped metal circuit components 34 and 34a having male blade terminals 38 and 38a arranged in a predetermined pattern and maintained in this predetermined pattern by the insulator board 36, preferably by insert moulding the stamped metal circuit components 34 in an insulator board 36 of moulded thermoplastics material. One advantage of insert moulding the stamped metal circuit components 34 and 34a is that it immobilizes the male blade terminals 38 and 38a so that there is little, if any, relative movement between the male blade terminals 38 and 38a and the electrical wires connected to it, as described below. This is important in maintaining the integrity of the these electrical connections. Another advantage is that insert moulding is an efficient manufacturing process which can reduce the number of components and manufacturing cost. Nearly all of the male blade terminals 38 and 38a include a narrow wire receiving slot or slots 40 of the insulation displacement type near the base of its blade which is provided by a short finger 42 disposed on one or both sides of the blade, as best shown in Figures 5 and 6. The width of the wire receiving slots 40 is narrower than the conductor core of the wire it receives so that electrical contact is established when the wire is pushed into the slot, in a well know manner. The stamped metal circuit components 34, 34a have a relatively high current carrying capacity and thus are adequate for even the highest currents normally encountered in automotive wiring circuits, that is up to around 40 amps continuous current. This is especially necessary for the main stamped metal circuit component 34a which is a power bus including an ear portion 34b for connection to a battery cable (not shown) and high capacity male terminal blades 38a for connection to maxi-fuses 14. The upper and lower bus plates 30 and 32 each comprise a routing board 44 of electrically insulating thermoplastics material which includes a plurality of terminal stations 46 and a plurality of guide stations 48. The terminal and guide stations are raised and separated from each other so as to provide a network of wire channels which communicate with wire passages extending through the terminal and guide stations. The terminal stations 46 also have terminal slots 50 extending through the routing board 44 to intersect the wire passages. The upper and lower bus plates 30 and 32 each include electrical buses comprising lengths of electrically conductive wire 52 passing through various terminal and guide stations via the network of wire channels in a predetermined pattern. Suitable bus plates and a suitable method of their manufacture are disclosed in greater detail in US-A-4,684,765. The electrically conductive wire 52 used in the upper and lower bus plates 30 and 32 is preferably a solid core 20 gauge copper wire which is easily routed onto the routing boards 44 and also adequate to carry the relative low current bus between wiring harnesses, that is up to about 15 amps continuous current. As indicated in US-A-4,684,765, the routing of the wire 52 onto the routing boards 44 is an automatic process which can be reprogrammed quickly to create any configuration of wire routing. Thus, the low current bus circuits (which are most likely to change often for automotive wiring applications) can be created and changed easily with minimal cost and time. This flexibility provided by the routed wire bus plates 30 and 32 combined with the high current carrying capacity of the stamped metal circuit bus plate 28 is a major advantage of this embodiment. The routing boards 44 used in the upper and lower bus plates 30 and 32 are preferably identical in order to minimize the number of parts and reduce production costs. The routing boards 44 are assembled to the main bus plate 28 with their respective networks of wire channels facing the main bus plate 28. Thus, the routing board 44 for the upper routed wire bus plate 30 is effectively upside down while the identical routing board 44 for the lower bus plate 32 is shown right side up, as viewed in the Figures. After completion, the bus plates 30 and 32 are assembled to the main bus plate 28, one at a time, by pressing their respective routing boards 44 over the protruding male blade terminals 38, 38a of the main bus plate 28, which pass through the terminal slots 50 as the routed wire bus plates 30 and 32 are pressed onto the main bus plate 28. This action forces the solid core wire 52 into the wire receiving slots 40 of the male blade terminals 38, 38a establishing electrical connections and creating bus circuits between the male blade terminals 38, 38a as shown in Figures 4, 5 and 6. The main bus plate 28 has a plurality of round mounting holes 54, while the routing boards 44 for the upper and lower bus plates 30 and 32 have larger square holes 56, as best illustrated in Figure 6. These larger square holes 56 leave the surfaces of the insulation board 36 of the main bus plate 28 adjacent the round mounting holes 54 exposed after a routed wire bus plate 30 or 32 is fitted. After one routed wire bus plate is assembled to the main bus plate 28, these exposed surfaces are used to support the main bus plate 28 for assembly of the second routed wire bus plate on the opposite side of the main bus plate. The main bus plate 28 includes a plurality of integral raised abutments 58 and integral posts 60 on its upper and lower surfaces. The raised abutments 58 engage the guide stations 48 and hold down any wires 52 passing through the guide stations when the routed wire plates 30 or 32 are pressed onto the main bus plate 28. The integral posts 60 adjacent the longer edges of the insulation board 36 are received in mating holes 62 of the routing boards 44 of the bus plates 30 and 32 when these bus plates are pressed onto the main bus plate 28. The integral posts 60 are heat staked or otherwise enlarged at their ends after the routed wire bus plates 30 and 32 are pressed on so that the main bus plate 28 and routed wire bus plates 30 and 32 are fixed to each other and form a unitary sub-assembly 64, as best shown in Figure 4. The immobilization provided by the formation of the unitary sub-assembly 64 together with the immobilized male blade terminals 38 and 38a of the insert moulded main bus plate 28 enhances the electrical connections between the male blade terminals 38 and 38a and the wires 52 received in the wire receiving slots 40 because there is virtually no movement between these components due to vibration or shock. The unitary sub-assembly 64 is assembled into the lower housing 24 and properly located by three longitudinally spaced, integral, hollow stems 66 in the lower housing 24 (best seen in Figure 5). The lower housing 24 has a plurality of slots 68 that extend through its floor so that the male blade terminal 38, 38a of the sub-assembly 64 protruding below the sub-assembly passes through the floor and into the connector sockets 18 depending from the bottom of the housing 24. After the unit handled sub-assembly 64 is placed in the lower housing 24, double-ended female terminals 70 are fitted onto selected ones of the male blade terminals 38, 38a protruding above the sub-assembly 64. The upper housing 26 is then fitted on the lower housing 24 and secured by bolts 72 screwed into the two end hollow stems 66. The attached upper housing 26 holds the sub-assembly 64 against the floor of the lower housing 24, as shown in Figure 4. The upper housing 26 also has elongated terminal cavities 74 which receive the double-ended female terminals 70 attached to the protruding upper ends of selected male blade terminals 38, 38a. The elongated terminal cavities 74 have slot-shaped entrances opening onto the upper surface of the upper housing 26, as shown in Figure 2, so that the mini-fuses 12, maxi-fuses 14 and relays 16 can be plugged into the electrical distribution centre, as shown in Figure 1. These electrical and electronic devices are then preferably held down and protected by the cover 22 which is secured to the centre hollow stem 66 by a knobbed fastener 76 having a threaded shank. While sub-assembly 64 has been shown to include three stacked bus plates, that is a main "stamped metal circuit" bus plate 28 sandwiched between two "routed wire" bus plates 30 and 32, it is possible to add more bus plates. For instance, Figure 7 shows an alternate embodiment of electrical distribution centre 100 having a sub-assembly 164 comprising a main "stamped metal circuit" bus plate 128 and three "routed wire" bus plates 130, 132 and 134. The main bus plate 128 has protruding male blade terminals 138a and 138b of different configurations to accommodate the two bus plates 130 and 132 pressed onto the upper surface of the main bus plate 128. More specifically, the male blade terminals 138a have low level wire receiving slots 140a receiving the wires 152a of the "routed wire" bus plate 130 immediately above the main bus plate 128. Conversely, the male blade terminals 138b have high level wire receiving slots 140b receiving the wires 152b of the "routed wire" bus plate 132 of the first "routed wire" bus plate 130. The modified electrical distribution centre 100 shown in Figure 7 has a single "routed wire" bus plate 134 below the main bus plate 128. However, it too can be modified to accommodate a fourth "routed wire" bus plate below the bus plate 134, by modifying the male blade terminals 138a and 138b to accommodate a fourth bus plate. Any suitable number of "routed wire" bus plates may be provided.

Claims: An electrical distribution centre for providing electrical interconnections between electrical and/or electronic devices and one or more electrical connectors of one or more wiring harnesses, comprising a first bus plate (28) including a plurality of stamped metal circuit components (34,34a) and an insulation board (36) for fixing the stamped metal circuit components in a predetermined pattern, at least one of the stamped metal circuit components being in use connected to a relatively high current source and including a first plurality of male blade terminals (38,38a) projecting from the insulation board, others of the stamped metal circuit components including a second plurality of male blade terminals (38,38a) projecting from the insulation board; and at least one second plate (30,32) including a plurality of circuit components (52) of relatively low current carrying capacity and an insulated board (44), the or each second bus plate including first and second slots (46) extending through the insulated board, the circuit components extending across selected ones of the second slots, the first plurality of male blade terminals extending through the first slots of the or each second bus plate for connection with selected electrical and/or electronic devices located in use on a side of the or each second plate opposing the first bus plate; characterised in that the or each second plate (30,32) serves as a bus plate routing and fixing wire circuit components (52); and in that the stamped metal circuit components have a wire receiving slot (40), the wire receiving slots of selected ones of the second plurality of male blade terminals passing through the second slots of the or each second bus plate receiving the wire circuit components of the or each second bus plate. An electrical distribution centre according to claim 1, wherein the or each second bus plate (30,32) includes an insulated routing board (44) which comprises a network of channels in a surface of the second bus plate, the second slots (46) of the second bus plate communicating with the network of channels. An electrical distribution centre according to claim 1 or 2, comprising upper and lower second bus plates (30,32) each including a plurality of wire circuit components (52) of relatively low current carrying capacity and an insulated routing board (44) for fixing the wire circuit components in a predetermined pattern. An electrical distribution centre according to claim 3, wherein the upper and lower second bus plates (30,32) are disposed on opposite sides of the first bus plate and are pressed on the first plurality of male blade terminals to cause a surface of each second bus plate which includes the or a network of channels to abut the insulation board (36) of the first bus plate. An electrical distribution centre according to any preceding claim, wherein the first and the or each second bus plates include fixing means (60) for fixing the first and second bus plates together to form a unitary sub-assembly. An electrical distribution centre according to any preceding claim, wherein the stamped metal circuit components (34,34a) of the first bus plate (28) are insert moulded in the insulation board (36).

Inventors: GARRETSON JAY HAROLD, HAMILL BRIAN DAVID, KIRALY PATRICK STEPHEN, MONROE AARON DILLON, SCHMIDT THEODORE RAYMOND, GARRETSON, JAY HAROLD, HAMILL, BRIAN DAVID, KIRALY, PATRICK STEPHEN, MONROE, AARON DILLON, SCHMIDT, THEODORE RAYMOND
Applicants: GEN MOTORS CORP, GENERAL MOTORS CORPORATION
Application year: 1993
Main classification: B60R16
IPC codes: H01R9, B60R16, H01R25, H01R4, H05K7