GB2234922A - Electrical connectors - Google Patents

Abstract

An electrical connector of generally elongate form with integral terminals 102 projecting outwardly from each side is formed by cutting from a sheet of conductive material. The remaining sheet material 104 attached to the connector between the terminals 102, is bent away from the terminals to leave them freely projecting and may be bent away far enough to contact the connector body 110 thereby to increase the thickness and thus the current carrying capability thereof. Multiple connectors can also be arranged in a desired relative disposition by "potting" in a settable resin. <IMAGE>

Description

ELECTRICAL CONNECTORS This invention relates to an electrical connector of the bus bar type having an elongate body section with integral projecting terminals.

Electrical connectors of the above kind are used to interconnect devices in electric power supply circuits.

Known connectors are commonly made from copper strip, the desired bus bar shape being stamped out of the strip. If a larger current handling capability is required, then it is common to increase the width of the body section of the bus bar. However in all cases the portions of the copper strip cut to define the projecting terminals are removed as waste.

It is an object of the present invention to produce an electrical bus bar connecter with reduced wastage material, and at the same time to permit an increase in the current carrying capability without necessitating an increase in the width of the body section of the connector.

According to one aspect of the invention therefore there is provided a method of producing an electrical bus bar connector in which a strip of conductive material is cut to define an elongate body section, a plurality of terminals extending transversely thereof, and remaining material between the terminals, said remaining material being bent away to leave the terminals freely projecting.

According to a second aspect of the invention there is provided an electrical bus bar connector formed from conductive material and comprising an elongate body section, a plurality of spaced terminals projecting transversely thereof, and remaining said conductive material attached to said body section and extending between said terminals, said further material being bent away to leave the terminals freely projecting.

The connector may have a plurality of side-by-side terminals projecting on at least one side of the body section and the remaining material at such side between the terminals may comprise separate sections of remaining material linked only by the body section or may comprise sections which are also linked at ends thereof remote from the body section thereby to form a continuous bent back strip. Where such sections of remaining material are provided on each of two opposite sides they may be bent away sufficiently to bring the ends of the sections of one side into contact or close proximity with the ends of the sections on the other side and if desired such ends may be conductively secured together.

Alternatively the section of remaining material on one side of the body section may be bent away in an opposite direction to the section on the opposite side. Thus one section may be bent upwardly and the other section downwardly.

Each respective section may be bent sufficiently in order to contact upper and lower surfaces of the body section respectively. The ends of the bent back sections may be conductively secured to the body section if desired.

The bending away of the remaining material may be effected to any extent as desired and as appropriate. Thus, the material may be folded away so as to overlie the body section i.e. such that it contacts or lies closely ajacent to the body section. This arrangement is especially appropriate where ends are secured together as mentioned above. However, other arrangements involving only partial folding away or displacement are also possible.

With the invention a bus bar connector can be easily and conveniently manufactured with little or no wastage of material. A further advantage is that the current carrying capability of the bus bar connector can be increased because of the increased amount of conductive material comprising the body section, without requiring large increase of the width of such section. Due to the increased surface area of the body section it is possible that any losses due to the "skin effect" can be reduced.

The strip of conductive material from which the connector is cut may be flat and generally rectangular and may be formed from copper. The integral terminals may be cut out by for example stamping, so as to extend perpendicularly to the body section. The terminals may have holes in their free end regions to receive fixing bolts.

There may be provided two kinds of terminal on the bus bar, a supply input terminal for connection to a source of electric supply, and a plurality of supply output terminals for connection to appropriate electrical devices. The terminals may be identical or may be distinguishable by, for example, the input terminal being wider than the output terminals. The terminals may be coplanar with the body section or one or more terminals may be displaced relative thereto.

In the latter respect the terminals may be bent such that they adopt a cranked configuration. This allows an assembly of a number of such connectors to be arranged.

According to a third aspect of the present invention therefore there is provided an assembly of electrical connectors comprising a plurality of connectors disposed one on top of another, said connectors being contained within a structure which holds the connectors spaced from and insulated relative to each other, wherein the said containing structure comprises a solid body of polymeric material within which the connectors are embedded.

The third aspect of the invention may have some or all the features of the first and second aspects.

Preferably each connector has, affixed thereto so as to project from edges thereof a plurality of terminals and futhermore preferably each connector and the respective terminals are formed integrally in one piece.

The assembly of connectors may comprise any number of connectors and may be arranged such that the terminals of each connector interleave with those of the other connectors in the assembly. Thus the assembly may be arranged such that the interleaved terminals extend parallel to each other and the terminals on each side of the assembly may be coplanar. Preferably all the terminals are in a coplanar relationship.

The assembly of connectors of the invention may be used for any suitable purpose in any suitable context but may be particularly suitable for use in the interconnection of electrical devices such as circuit breakers (e.g. miniature circuit breakers and moulded case circuit breakers), fused switches, isolators and the like handling voltages and currents up to say 600 volts and 800 amps or higher.

If desired one or more connectors may be 'potted' in a polymeric material.

With regard to the polymeric material this may comprise any suitable extended, filled or unfilled system. For example, any suitable polyurethane, epoxide, polyester, mettacrylic or acrylic resin which may contain any suitable inert non-conductive filler may be used.

Once 'potted' the or each connector may be removed from the mould. Alternatively the or each connector or assembly of connectors may be retained in the mould, the mould forming the packaging for the assembly. Thus the mould may be a closed hollow structure. The mould may be one or two pieces or may be formed from any number of parts as desired The mould may enclose the terminals or may have apertures on each side thereof through which the terminals may extend, and the mould may have further filling openings through which the resin may be introduced into the interior of the mould.

The invention will now be described further by way of example only and with reference to the accompanying drawings of which: Fig. 1 shows three bus bar structures used in the manufacture of one form of an electrical connector which is an encapsulated universal bus bar assembly according to the invention; Fig. 2 shows a perpective view of one form of a connector shown at an intermediate stage in the formation thereof.

Fig. 3 shows an end view of an alternative form of connector after folding; Fig. 4 shows an end view of the connector of Fig. 3 with cranked terminals; and Fig. 5 shows a perspective view of an assembly of connectors stacked in a mould.

Fig. 1, shows three copper bus bar structures 1, 2, 3 each comprising a respective flat rectangular plate 4, 5, 6 with flat strip-shaped terminals 7, 8, 9, 10, 11, 12 projecting perpendicularly from edges of the plates 4, 5, 6. Each plate 4 or 5 or 6 and the respective terminals 7, 8 or 9, 10 or 11, 12 are stamped out in one piece from a copper sheet. The three plates 4, 5, 6 are of different lengths but of the same width.

One bus bar structure 1 has two terminals 7 on each of two opposite long edges of the plate and one terminal 8 on one short edge. The terminals 7, 8 are all coplanar with the plate 4. The terminals 7 on the long edges are all of a common width which is less than that of other terminal 8.

One of the other bus bar structures 2 has two terminals 9 on each of two opposite long edges of the plate, all of which terminals 9 are of common width, (equal to that of the terminals 7), and a further terminal 10 on one long edge adjacent to one short edge which is of greater width than that of the terminals 9 (and is equal to that of the terminal 8). The terminals 9 are bent as shown so that free end portions of the terminals 9 lie in a common plane parallel to and spaced from the plate 5.

The third bus bar structure 3 has four terminals 11 of common width and one wider terminal 12 and is of the same construction as the bus bar structure 2 except that the terminals 11 are spaced differently from the terminals 9 as shown.

All terminals 7-12 have bolt holes in their free end regions.

The bus bar structures 1, 2, 3 are stacked on top of each other within a mould with the free end regions of the terminals 7-12 projecting through slots in side walls of the mould whereby the bus bar structures 1-3 are held in predetermined spaced disposition with the terminals 7-12 in desired position relative to each other.

As shown, the positioning of the bus bar structures 1-3 is such that all end regions of all terminals 7-12 are coplanar, the three wider terminals 8, 10, 12 are at the same end of the assembly of the bus bar structures, and the narrower terminals 7, 8, 11 are at least generally evenly spaced at each long side of the assembly. At each side, these terminals 7, 9, 11 terminate level with each other and form a row of two sets of three terminals, the terminals 7, 9, 11 of each set relating respectively to the three bus bar structures 1, 2, 3.

A pourable, settable polymeric material comprising a suitable resin (e.g. polyurethane, epoxide, polyester, mettacrylic or acrylic) and an inert non-conductive filler is poured into the mould so as to fill the mould between and around the plates 4, 5, 6. The polymeric material is then caused or allowed to cross-link and set hard thereby to encapsulate the plates 4, 5, 6 rigidly in a block of polymeric material from which the coplanar end regions of the terminals 7-12 freely project. The plates 4, 5, 6 are pre-primed (by painting, spraying, dipping or tinning with an appropriate material) prior to encapsulation to ensure adhesion of the polymeric material.

The encapsulated bus bar assembly is then detached from the mould by removing the mould walls. The assembly can then be used as an electrical connector by connecting the three wider terminals 8, 10, 12 to three-phase supply input and by connecting the narrower terminals 7, 9, 11 at each long side to electrical devices (circuit breakers etc.).

It will be seen that two devices can be connected to each side.

The connector described above can be manufactured easily and conveniently to give a desired number and arrangement of terminals. Changes to suit different electrical devices can be readily accommodated by appropriately changing the stamping out of the bus bars and/or by appropriately adjusting the positioning of the bus bars in the mould before the polymeric material is poured and set.

Alternative embodiments are described hereinafter with reference to Figs. 2 to 5.

With reference to Fig. 2, a solid rectangular strip of conductive material, i.e. copper, is cut to the desired size and shaped to define a rectangular central elongate section 100, two opposed sets of generally rectangular terminals 102 symmetrically disposed respectively on each side of the centre line of the central section and extending perpendicularly thereto, and a single terminal 103 at one end of the central section aligned with the central line.

The terminals 102 are of a common width and the terminal 103 is wider.

The width of the strip is greater than the width of the central section 100 and projecting terminals 102, and the terminals 102 are cut out simply by the formation of cuts around their peripheries. This leaves remaining material 104 of the strip between and beyond the terminals 102 forming intermediate tab-shaped sections 105 linked at their ends remote from the central section by an edge strip 106. This strip 106 may also link with end tab sections 107 beyond the end terminals. The wider supply terminal 103 may be cut out by removing completely material on each side.

Once the terminals 102, 103 have been cut out, the remaining material of the strip is folded along the two fold lines parallel and symmetrical with respect to the central line defined by uncut sides 108 of the intermediate end tab sections until the free edges 109 of the edge strips 106 meet and the remaining material contacts the surface 110 of the central section 100.

The two edges 109 are joined together along their whole length by for example tinning. Thus there is formed a single conducting block of greater thickness and hence current carrying capability than the body section 100 alone. Problems due to the presence of the surface eddy currents ("skin effect") can be minimised with this structure.

Once assembled in this way the bus bar connector may be conveniently mounted (together with one or more other like connectors) within the body of a polymeric material with only the terminals projecting outside of the body in a coplanar arrangement in a manner to be described hereinafter.

If desired the two free edges 109 of the edge strips 106 need no be joined together, and the remaining material need not be bent back far enough to contact the central section 100. Also, although it is desirable to link the tab sections 105 with the edge strips 106, if desired the edge strips 106 can be omitted (by cutting through to the edge 109 of the strip) to give separate tab sections 105 linked only by the central section 100 of the connection.

In an alternative embodiment, as shown in Fig. 3, the connector 200 is cut from the conductive material strip as described above. However in this embodiment when the remaining material is folded along the two fold lines, the material 201 on one side of the central line, as defined by uncut sides of the intermediate end tab sections, is folded upwardly and over the central section and the material 202 on the other side is folded downwardly and under the central section.

The material from both sides is folded into contact with the top and bottom surfaces of the central section respectively increasing the total thickness thereof.

At one end of the connector, on each side of the central section, two terminals are cut closely spaced for each other. The two end terminals are folded downwardly under the central section and into contact with adjacent two terminals thus creating two terminals 203, 204 of increased thickness. These two terminals can be used for connection to a power supply.

The advantage of this arrangement lies in the fact that it is possible for the transverse dimensions (i.e. width) of the connector 200 to be decreased whilst still maintaining the advantages of increased current carrying capability due to the increased thickness of the conductive material in the central region. Indeed in this respect it is also possible to bend the terminals such that they become cranked, as shown in Fig. 4, in order to further reduce the transverse dimension and facilitate ease of assembling a number of such connectors.

As mentioned above it is possible to encapsulate a number of such connectors within a body of polymeric material with only the terminals projecting outside of the body in a coplanar arrangement. To achieve this it is necessary to mount the connectors in a desired arrangement in a mould, fill the mould with a polymeric material, remove the assembly of connectors thus formed and package the assembly.

In Fig. 5 there is shown an assembly of connectors 300 mounted within a mould 301. The mould 301 is formed from a plastics material which is of rigid enough construction to retain its shape during encapsulation and to afford a reasonable degree of protection to the assembly 300 once encapsulated. It is envisaged that the mould 301 will be retained around the assembly 300 subsequent to encapsulation and will be of a kind suitable to form a packaging for the assembly 300 thereby removing the need for further packaging.

The mould 301 is formed from two separate halves 302, 303 adapted to cooperate with each other and to be joined along adjacent edges when placed together. An upper half 303 of the mould 301 is shaped to define a generally U-shaped channel 304 having outwardly projecting edges 305, 306 from the channel walls 307, 308. The walls 307, 308 of the channel 304 are tapered outwardly from the axis of symmetry of the mould 301. A lower half 302 of the mould 301 is similarly configured to the upper half 303 and has a channel having outwardly projecting edges 340, 341 at upper ends of the channel walls 342, 343 which are arranged to cooperate with the like edges 305, 306 on the upper mould half 303 to form side extensions to the mould 301. The lower mould half 302 has further leg extensions 345 of generally rectangular configuration spaced along its length.In the embodiment shown in Fig. 4, three such leg extensions are shown disposed one at each end of the mould 301 and another in the centre of the mould 301. The leg extensions 345 have apertures (not shown) in the lower ends 346 thereof through which the polymeric material may be introduced into the interior of the mould 301 when the assembly is complete.

Thus the mould 301 is filled from the bottom and is then turned over.

The assembly of connectors 300 is disposed in the lower half 302 of the mould 301. The arrangement shown in Fig. 4 comprises three connectors 350, 351, 352 stacked one on top of the other, with their body sections substantially parallel and the terminals being evenly spaced and projecting outwardly into the side extensions. The top 350 and bottom 351 connectors are of the type having cranked terminals whilst the intermediate one 352 has planar terminals projecting transversely from the central section. The arrangement is such that when the connectors 350, 351, 352 are assembled together as described above the terminals interleave and all end regions of the terminals are coplanar. The connectors 350, 351, 352 are all of the type with the remaining material on one side folded under the central section and the remaining material on the other side folded over the central section.

With the two halves of the mould 302, 303 joined together and the desired arrangement of connectors 350, 351, 352 disposed in the mould 301 the side extensions can be sealed in order to prevent the terminals being encapsulated in the polymeric material. The extensions can be sealed by welding the mould 301 to the terminals along the lines of the channel walls 307, 308, 342, 343 by any suitable means for example RF welding or the application of heat or the like.

The polymeric material is introduced into the mould 301 via the apertures 346 in the leg extensions 345. The polymeric material is a settable resin compound and will encapsulate the connector assembly 300, when set, in a rigid block of such material in accordance with the configuration of the mould 301. Thus by appropriate shaping of the mould 301 it is possible to achieve encapsulation of an assembly of connectors 300 of any desired configuration.

In order to expose the terminals when using the assembly 300 the mould 301 can be selectively broken along the line of the weld, the welding process having created a weakness in the mould 301 along this line. Furthermore it is possible to incorporate a back plate (not shown) into the arrangement to aid mounting of the assembly 300 for example after introduction of the resin into the mould 301 and before it has set, a back plate (not shown) having spaced pins protruding therefrom can be attached by introduction of the pins into the resin through the apertures 346 in the leg extensions 345. Thus when the resin sets the back plate is held in position and can be used to fix the assembly 300 to a wall or other structure. Also the configuration of the mould 301 allows passage of cables or wires through the spaces between the leg extensions 345 when so mounted.

With the arrangements described above it is possible for a connector to be manufactured with little or no wastage of materials. Furthermore the current carrying capability of the connector can be increased without a corresponding increase in connector width. A further advantage lies in the ability to accomodate a range of different electrical devices by adjusting the configuration and number of connectors in the mode.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiments which are described by way of example only.

Thus for example prior to encapsulation of one or more connectors within the settable resin, all or at least a part of the or each connector can be provided with a coating of paint or plastics material to enhance adhesion to the resin material when set.

Claims (19)

1. A method of producing an electrical bus bar connector in which a strip of conductive material is cut to define an elongate body section, a plurality of terminals extending transversely thereof, and remaining material between the terminals, said remaining material being bent away to leave the terminals freely projecting.

2. An electrical bus bar connector formed from conductive material and comprising an elongate body section, a plurality of spaced terminals projecting transversely thereof, and remaining said conductive material attached to said body section and extending between said terminals, said remaining material being bent away to leave the terminals freely projecting.

3. A connector according to claim 2 wherein said terminals are disposed side-by-side and project on at least one side of the body section.

4. A connector according to claim 2 or 3 wherein said remaining material comprises separate sections linked only by the body section.

5. A connector according to either claim 2 or 3 wherein said remaining material comprises sections which are linked at ends thereof remote from the body section thereby to form a continuous bent back strip.

6. A connector according to any one of claims 2 to 5 wherein sections of said remaining material are provided on each of two opposite sides of said body section and such sections are bent away sufficiently thereby to bring the ends of the sections of one side into close proximity or contact with the ends of the sections on the opposite side.

7. A connector according to any one of claims 2 to 5 wherein sections of said remaining material are provided on each of two opposite sides of the body section and said sections on one side of said body section are bent upwardly to contact an upper surface thereof and said sections on the other side of said body section are bent downwardly to contact a lower surface thereof.

8. A connector according to claim 6 or claim 7 wherein said ends of the bent away sections are conductively secured to said body section.

9. A connector according to any one of claims 2 to 8 wherein an input terminal is provided which is wider than the remainder of the terminals.

10. A connector according to any one of claims 2 to 8 wherein said terminals are bent to adopt a cranked configuration.

11. An assembly of electrical connectors comprising a plurality of connectors, having projecting terminals, disposed one on top of the other, said connectors being contained within a structure which holds the connectors spaced from and insulated relative to each other, wherein the containing structure comprises a solid body of polymeric material within which the connectors are embedded.

12. An assembly according to claim 11 wherein the terminals of each connector interleave with those of the other connectors such that said terminals extend in a coplanar fashion.

13. An assembly according to claim 11 or claim 12 further including a mould within which said assembly is disposed.

14. An assembly according to claim 13 wherein said mould is formed from two parts adapted to be linked together along adjacent edges thereof.

15. An assembly according to claim 13 or claim 14 wherein said mould is provided with filling openings through which said polymeric material is introduced into the interior of the mould.

16. An assembly according to any one of claims 11 to 15 wherein said polymeric material comprises a settable resin

17. A method substantially as hereinbefore described with reference to the accompanying drawings.

18. A connector substantially as hereinbefore described with reference to and as illustrated in Figs. 1, 2, 3 or 4.

19. An assembly of connectors substantially as hereinbefore described with reference to and as illustrated in Fig. 5.