BUSBAR JOINT WITH MEANS FOR ATTACHING A COVER

Abstract: The figure shows a length of busbar (1) carrying elongate conductors (2, 3, 4, 5) extending beyond the end of said length and straddled by two side plates (6) and (7) which provide means on which a cover may be mounted. The side plates (6, 7) are fastened to a joint pack (2) with said plates extending into slots (9, 10).

Description: Busbar joint with means for attaching a cover This invention relates to improvements in or relating to busbars and is more particularly concerned with the manner in which lengths of busbar conductors are connected together in end-to-end relationship. Various designs of busbar are in operation and these may consist of trunking having an extruded aluminium alloy channel shaped housing defining a base and side walls and an interlocking top cover strip made of Noryl (insulating material). This form of busbar is in use by the Applicant Company, and four or five elongate conductors, for example of aluminium or copper extend side-by-side within the housing. In order to join the elongate conductors together joints (known as joint packs) are utilised consisting of a number of metal conductor plates and insulation plates mounted on a central bolt with spring means extending inbetween the plates around the bolt. Reference is made to our co-pending application of even date for a joint, the content of which is included in this application by way of appendix A. It is known to connect elongate conductors together using "joint packs" and it is known for shaped side plates to be attached to the busbar trunking in a manner straddling the elongate conductors and extending parallel with them to be received in associated slots in the joint pack, more particularly as described in the first paragraph of page 11 of Appendix A. The two side plates are joined in end-to-end relationship (but not in contact) with a second pair of side plates extending from an adjoining length of busbar into opposed slots in the joint pack. When such prior art trunking joints (side plates) are utilised a cover is provided on either side of the busbar to obscure the joint pack from view. In order to connect the covers to each length of busbar to bridge the gap in the trunking packing pieces have to be connected to each length of busbar to provide supporting edges on which the associated cover can engage. The packing pieces normally take the form of metal bars of square cross section which are bolted to the trunking transverse to the trunking axis. Thus, in employing the side plates straddling the elongate conductors, it is also necessary to provide some means of covering the joint pack and gap and the Applicant believes that having to provide separate packing pieces tends to be disadvantageous for several reasons. Firstly, it is believed that the connection of two busbar lengths in end- to-end relationship is more time consuming that need be the case, the connection of the packing pieces to the trunking being a time consuming operation which in itself may not be necessary. Additionally, the extra material required and cost of the packing pieces may perhaps be avoided or alleviated if another design of cover attachment were provided. It is believed there may be other disadvantages with the aforementioned arrangement. Accordingly, it is an object of the present invention to at least alleviate one or more of the aforementioned, or other, problems involved in joining together busbar lengths or to provide an improved trunking joint. According to the present invention there is provided a joint for joining together lengths of busbar, said joint comprising two side plates which, in use, lie on either side of or straddle elongate conductors of the busbar and engage a conductor joint joining together said elongate conductors, said side plates being provided with means on which a cover can be mounted. In this way, there is no need to provide separate packing pieces attached to each busbar length for mounting the cover. Thus, once the side plates have been assembled together in the conductor joint and to each busbar length a cover can be located easily onto said means provided on the side plates. It is envisaged that two covers will be mounted opposed to one another on said means to cover the front and rear of the joint bridging the gap (i.e. the top and bottom of the busbar in use) between the two lengths of busbar. The means on which the cover may be mounted may comprise a generally rectangular projecting wall portion having opposed side walls over which flanges of the cover can be engaged. Alternatively, said opposed side walls of said rectangular wall portion may be provided with mounting plates (preferably bolted thereto and/or preferably of angle section) having means for mounting the associated cover thereto. Holes may be provided in the mounting plates to receive screw fastening means passing through slots in the cover thereby allowing some adjustability of the cover along the busbar to take into account any tolerances in fitting of the conductor joint to the side plates. Additionally, and advantageously the mounting plates may connect each plate of the pair securely together giving a greater degree of rigidity to the joint. In one embodiment of the present invention the trunking joint comprises four side plates, one pair of side plates in use being fitted on to one length of busbar straddling elongate conductors extending beyond the busbar tracking and the other pair of side plates being connected to an adjoining length of busbar trunking in a manner surrounding the elongate conductors extending beyond the end of that length of trunking. Usually each of the side plates will have a flange which is connected to the busbar by fastening means such as a bolt and preferably the side plates will have tabs (preferably projecting at right angles to the flange and inwardly thereof) which fit together when the pair of side plates is assembled in order to define a closed opening for snugly receiving the elongate conductors. Usually, the side plates of the pair will be separately formed rather than being integrally made owing to the fact that the opening will usually embrace the elongate conductors at a position before they have been splayed apart and thus it would not be feasible to slot the splayed apart elongate conductors through the opening if the conductors are to be snugly received. Nevertheless, it is possible that in some embodiments the side plates of one pair may be integrally formed, more particularly if the means for mounting a cover is to be provided at the top or bottom of the busbar only i.e. a front cover might be provided bridging the gap inbetween two lengths of busbar trunking without a rear cover also being provided. Owing to the manner in which the elongate conductors are splayed apart the side plates of each pair need not be identical and it will be usual for one dimension of one of the side plates of the pair to be longer than a similar dimension of the other plate of the pair in order to cater for the asymmetric manner in which the elongate conductors may be splayed apart and indeed to cater for any asymmetry of the conductor joint itself. Provision may be made for the cover or covers to be adjustable along the lengths of busbar to cater for any tolerances that may be involved and this is preferably by angle section mounting plates connecting to the side plates in the manner previously stated. It is believed to be particularly advantageous to provide a closed opening snugly surrounding the elongate conductors since these will provide a firm and secure joint. Still further according to the present invention there is provided a kit of parts including at least one length of busbar and at least one trunking joint in accordance with the preceding statement of invention. Further according to the present invention there is provided a method of connecting together two busbar lengths using a joint in accordance with the statement of invention as recited on page 3 of this specification. Further advantageous features of the present invention will be evident from the following description and drawings. An embodiment of a joint for joining together two lengths of busbar in end-to-end relationship will now be described, by way of example only, with reference to the following much simplified accompanying drawings in which: FIGURE 1 shows a front view of a joint pack connected to side plates of a busbar trunking joint in accordance with the present invention provided at one end of a busbar length; FIGURE 2 shows a sectional view taken on line 11-II of FIGURE 1 ; FIGURE 3 shows a view of the end of the busbar and trunking joint side plates looking in the direction of arrow A on FIGURE 2; FIGURE 4 shows to a different scale a view similar to FIGURE 1 with a cover (cut away) which in use covers the trunking joint and bridges a gap in between two lengths of busbar placed in end-to-end relationship; FIGURE 5 shows to a different scale views views of one of the side plates in orthographic projection; FIGURE 6a shows in oblique projection but not to scale two side plates of the trunking joint brought together prior to attachment to a length of busbar in juxtaposition to two side plates for attachment to an adjoining length of busbar; FIGURE 6b shows a view of a cover not to scale, FIGURE 7 shows views of a cover mounting plate connectable to a pair of side plates, and FIGURE 8 shows a view of the side plates fitted with cover mounting plates. Referring more particularly to the FIGURES 1 to 4 of the drawings, a length of busbar 1 (only the end of the busbar is shown in FIGURES 1 to 4) is generally of a known form comprising a section which is generally "H" shaped and carrying elongate conductors 2,3,4,5 (four in this instance) which extend outwardly beyond the end of the busbar length 1. The elongate conductors 2 to 5 are engaged in slots T of a joint pack 2 which forms the subject of our co-pending application of Appendix A. One half of the trunking joint J, in accordance with the present invention, comprises two side plates 6 and 7 which are brought together (in the manner as shown in FIGURE 6a) to define a rectangular opening 8 for receiving the elongate conductors 2,3,4,5 therethrough, such that the side plates 6 and 7 lie on either side of or straddle the elongate conductors and are received in slots 9 and 10 of the joint pack 2 (see FIGURE 1). The two side plates 6 and 7 are shown juxtaposed a similar pair of side plates 6a,7a (shown in dotted lines in FIGURE 6a) which in use will be connected to a second length of busbar (not shown) to be joined in end-to-end relationship with the busbar length 1. In practice, although side plates 6 and 7 are shown in contact with side plates 6a,7a, there will be a gap between the two pairs of side plates 6,7;6a,7a since they will not actually contact one another in the slots 9 and 10 of the joint pack 2, owing to the central channels C provided in the conductor plates P of the joint pack 2 as generally described in Appendix A. Thus, the joint J comprises the four side plates 6,7;6a,7a which are assembled together surrounding the ends of the elongate conductors 2,3,4,5 (and adjoining ends - not shown - of elongate conductors of a second length of busbar) and defining means on which a cover 11 (see FIGURES 4 and 6b) can be engaged. The trunking joint J defines a generally rectangular projecting wall portion 12 having opposed side walls 12a and 12b over which flanges lla and lib of the cover 11 can be engaged. Thus, the projecting side walls 12a,12b provide the means on the joint for engaging the cover 11. Similarly, rectangular wall portion 13 projecting from the joint J in the opposite direction to rectangular portion 12 forms means for attachment of a similar cover 11 covering the rear gap between two adjoining busbar lengths. In practice, the length of each cover 11 will be slightly longer than that shown in FIGURE 6b to cater for the gap which will exist in practice between the two pairs of side plates 6,7;6a,7a when engaged in slots 9 and 10. One of the side plates 7 is shown in orthographic projection in FIGURE 5. The other side plate 6 of the pair 6,7 is virtually identical to side plate 7 except that one dimension is longer to cater for the asymmetry of the joint pack 2 and the manner in which the conductor lengths 2 to 5 are splayed apart. Side plate 7 is provided with a first flat sheet portion 7b which curves at right angles at 7c to form projecting tabs 7d,7e which extend beyond and at right angles to side flange 7f lying inbetween the tabs 7d and 7e and parallel to portion 7b (but which is arranged slightly inwardly of portion 7b). As shown in FIGURES 1 to 3 and more particularly in FIGURE 3, the flange 7f (and also the flange 6f of side plate 6) is somewhat longer than shown in FIGURES 5 and 6a, said side plates 7f and 6f being bolted to the end of the busbar 1 by bolt B (see FIGURE 3). As previously mentioned, side plate 6 is similar to side plate 7 the difference being the length of the right angled tabs 6d (only one of which is shown) and the tabs 7d,7e. Additionally, the displacement between the flange 6f and flat portion 6b is somewhat greater than the displacement between the flange 7f and flat portion 7b of the side plate 7 in a manner which should be evident from the FIGURES of the drawings. Thus, in assembling the busbar length 1 in end-to-end relationship with another length of busbar the trunking joint J is used comprising side plates 6,7;6a,7a which are assembled together with one pair of side plates 6,7 being bolted to the end of the busbar 1 (by flanges 6f,7f) and the other pair of opposed side plates 6a,7a being bolted to the adjoining length of busbar with said side plates extending into the slots 9 and 10 of the joint pack 2. Additionally, one or more of the side plates 6,7;6a,7a can be connected directly to the joint pack using screw fastening means f (only one such fastening means shown in FIGURES 1 to 3). The projecting wall portions 12 and 13 contact the end of the busbar 1 and extend above and below the associated channel base Xχ,X2 respectively of the busbar 1 (as shown more particularly in FIGURE 2). The projecting wall portions 12 and 13 extend above and below the conductor lengths 2,3,4,5 close to the boundary limits of the busbar section for engagement of the flanges lla,lib of respective covers 11 shown at the top and bottom of the busbar 1 in FIGURE 2. AS shown in FIGURE 5, side plate 7 (and also side plates 6,6a,7a) is provided with two transverse grooves G (not shown in FIGURE 6a). The ring detail Z shows enlarged the form of each of the grooves G. Two slots S are defined at either end of the flange 7f and similar slots are provided on side plates 6,6a;7a. The grooves G enable better grip characteristics in the slots 9 and 10 of the joint pack. The embodiment of the present invention as aforedescribed may be modified to provide for some adjustability of the cover 11 which may be in the form of a flat plate (or of C-shaped cross section) having screw receiving slots S' provided at each corner (see FIGURE 4) . The modification is shown in FIGURE 8, where cover mounting plates 100 in the form of angle section (angle brackets) are bolted to opposed side walls 12a,12b of the generally rectangular projecting wall portion 12 in a manner which should be self-evident. One of the angle brackets 100 is shown in FIGURE 7. Each angle bracket 100 has screw mounting holes 101 to receive screws (not shown) which pass through the slots in the cover with the heads of the screws being movable along the slots a small amount to allow for some adjustability of the cover along the busbar in a manner which should be evident. Side walls 13a,13b may also be provided with angle brackets for mounting a cover at the bottom of the busbar, in use, in a manner which should readily be envisaged. A further important modification to the arrangement as described is the replacement of the threaded bolt and nut connections 200 (see FIGURE 4) with self-piercing rivets. Connecting the busbar extrusion lengths together back-to-back by the nut and bolt connections 200 requires the setting-up of a special jig and it is believed that the process of connecting together the busbar extrusions tends to be more laborious and possibly more expensive than need be the case. Thus, importantly and advantageously, the Applicant connects the busbar extrusions together in back- to-back relationship using self-piercing rivets which do not require the provision of a special jig in the same way as a nut and bolt connecting system. Although self- piercing rivetting systems are known for some applications it is believed that the application in this instance is both novel and inventive partly owing to the scale, thicknesses and type of material used for the busbar. In developing the system the Applicant has had to employ much stronger rivets and thus the application of a self-piercing rivetting method to hold the extruded sections of busbar together is something which could not have been expected. Nevertheless, the Applicant has managed to solve the problems posed by attaching the busbar sections together using self-tapping rivets. Therefore, still further according to the present invention there is provided a method of connecting together (extruded) lengths of busbar section, preferably in back- to-back relationship, by means of rivetting and preferably by rivetting with self-piercing rivets. Further according to the present invention there is provided a busbar length comprising two sections connected together along their length by means of (self-piercing) rivets, preferably arranged at equal spacings along the axis of the busbar. It is to be understood that the scope of the present invention is not to be unduly limited by a particular choice of terminology and that a specific term as used herein may be replaced or supplemented by an equivalent or generic term. For example, "plate" may be replaced by "member", "cover" may be replaced by "cover means". Further it is to be understood that the individual features, method or function relating to the trunking joint, or parts thereof might be individually or in combination patentably inventive. The singular may include the plural or vice versa. Additionally, the content of two further co-pending applications of the Applicant are included in this Patent Specification by reference and are attached hereto as Appendix B and Appendix C. The present invention may include features and concepts gleaned from this description and combined with any features from any of the appendices A,B and C.

Claims: CLAIMS 1. A joint for joining together lengths of busbar, said joint comprising two side plates which, in use, lie on either side of or straddle elongate conductors of the busbar and engage a conductor joint joining together said elongate conductors, said side plates being provided with means on which a cover can be mounted. 2. A joint as claimed in Claim 1 in which the means on which the cover can be mounted comprises a generally rectangular projecting wall portion having opposed side walls over which flanges of the cover can be engaged. 3. A joint as claimed in Claim 1 in which opposed side walls of a generally rectangular wall portion are provided with mounting plates having said means for mounting the associated cover thereto. 4. A joint as claimed in Claim 3 in which the mounting plates are bolted to the rectangular wall portion. 5. A joint as claimed in Claim 3 or Claim 4 in which the mounting plates are of angle section. 6. A joint as claimed in any one of Claims 3 to 6 having holes in the mounting plates to receive screw fastening means passing through slots in the cover. 7. A joint as claimed in any one of claims 3 to 6 in which the mounting plates connect the two side plates securely together. 8. A joint as claimed in Claim 1 comprising four side plates, one pair of side plates in use being fitted on to one length of busbar straddling elongate conductors extending beyond the busbar trunking and the other pair of side plates being connected to an adjoining length of busbar trunking in a manner surrounding the elongate conductors extending beyond the end of that length of trunking. 9. A joint as claimed in Claim 8 in which each of the side plates has a flange connected, in use, to the busbar by fastening means. 10. A joint as claimed in Claim 9 in which the fastening means is a bolt. 11. A joint as claimed in any one of Claims 8 to 10 in which the side plates have tabs. 12. A joint as claimed in Claim 11 in which the tabs project at right angles to the flange and inwardly thereof. 13. A joint as claimed in any one of Claims 8 to 12 in which the side plates of each pair are separately formed. 14. A joint as claimed in any one of the preceding claims in which one dimension of one of the side plates of the associated pair is longer than a similar dimension of the other plate of the pair. 15. A joint as claimed in any one of the preceding claims in which, in use, the cover is adjustable along the length of busbar. 16. A joint for joining together lengths of busbar substantially as herein described with reference to the FIGURES of the accompanying drawings. 17. A kit of parts including at least one length of busbar and at least one joint in accordance with any of the preceding claims. 18. A method of connecting together two busbar lengths using a joint in accordance with any one of Claims 1 to 16. 19. A method of connecting together (extruded) lengths of busbar section, preferably in back-to-back relationship, by means of rivetting and preferably by rivetting with self- piercing rivets. 20. A method as claimed in Claim 19 and substantially as herein described. 21. A busbar length comprising two sections connected together along their length by means of (self-piercing) rivets, preferably arranged at equal spacings along the axis of the busbar. 22. A busbar length as claimed in Claim 21 and substantially as herein described with reference to FIGURES 3 and 4 of the accompanying drawings.

Inventors: BROOKS KEVIN, BUTCHER ROBERT, REYNOLDS ANDREW, BROOKS, KEVIN, BUTCHER, ROBERT, REYNOLDS, ANDREW
Applicants: BROOKS KEVIN, BUTCHER ROBERT, KLOECKNER MOELLER GMBH, REYNOLDS ANDREW, BROOKS, KEVIN, BUTCHER, ROBERT, KLOCKNER-MOELLER GMBH, REYNOLDS, ANDREW
Application year: 1996
Main classification: H02G5
IPC codes: H02G5