GB2282278A - Trunking and busbars assembly - Google Patents

Abstract

A fixing element 103 is provided for use in attaching busbars to a synthetic polymeric trunking 3, in the form of a separate support channel with edge walls 104 between which clips 112 may be resiliently held. <IMAGE>

Description

TRUNKING AND BUSBARS ASSEMBLY This invention relates to the assembly, and to the components, of polymeric trunking and internal electrical supply means such as busbars.

It is well known to fabricate, as polymeric extrusions of indefinite length, profiles comprising a base, wall portions, and a cover to define a duct of uniform external appearance which can be attached to a wall, running along the skirting board or at any other desired height, and which can contain elongate electrical or other conductors, such as wires, printed circuit elements, fibreoptic materials, or the like.

A particularly useful ducting profile comprises a generally flat base with upstanding dividing walls, and cover members such as to define with the base and the wall a central duct and two parallel flanking ducts.

The invention is particularly concerned with, but not limited to, improvements in such ducting and related assembly components.

A major electrical connector which is utilized with polymeric and electrically insulating ducting in the form of busbars, that is to say, relatively large dimension electrical connectors extending along the ducting in parallel relationship and accessible at any point if the ducting is opened, whereby any desired electrical of fake unit can be added at any desired location along the ducting.

In one aspect the invention consists in extruded synthetic polymeric trunking, comprising at least a base and a removable cover which jointly define an elongate duct of indefinite length, in which the base is configured to present a pair of parallel upstanding walls each of which is shaped to retain fixing elements and/or a covering element for elongate metal bus bars lying within and parallel to the walls.

Preferably the upstanding configured walls are each shaped, over at least an upper part of their structure, as an upwardly open channel itself defined between two parallel channel walls. Preferably at least the laterally outer channel wall of each such channel has an out-turned edge. The two channels may be of identical or mirror image cross section, but in one preferred embodiment the laterally outer channel wall of one channel has its out-turned edge of greater lateral extension than that of the other out-turned edge of that same channel.

In such a case especially the laterally outer channel wall of one channel only may have an out-turned edge with a downwardly inclined lead surface.

One preferred embodiment of trunking has, along its base, two upwardly open channels both with out-turned channel wall edges. Preferably this structure is symmetrical about the centre of the base. It may be used in conjunction with conventional upstanding base ribs, and (as described below) permit both a covering element to be retained by the laterally outer out-turned edges, and fixing elements to be held by the laterally inner out-turned edge.

In another preferred embodiment the parallel upstanding walls, preferably shaped over at least an upper part of their structure as respective upwardly open channels have only a laterally outer outturned edge (e.g. for use to retain a covering element) and in which additional inner walls are provided, preferably symmetrically about the trunking base centre line, to locate and retain fixing elements. Such additional walls should not extend above the parallel upstanding walls and may themselves have laterally out-turned upper edges.

In another aspect the invention consists in fixing elements for use in attaching busbars within synthetic polymeric trunking, each in the form of a clip of a generally serpentine nature at least some of the convolutions of which possess flat opposed surfaces spaced apart by an amount to define a channel to hold a bus bar.

Preferably the clip is It is also preferred for each clip to be asymmetrical, that is to say, to define convolutions whereby a pair of bus bars may be held at mutual spacing different from their spacing in relation to a third busbar.

Because of the serpentine nature of the clip it possesses compressive resilience, whereby it can be pressed into restraint members to either side so as to one the one hand to be held by each restraint member and on the other hand to place the convolutions under compression so that the busbars themselves are gripped by the clip. This is discussed in more detail below.

The restraints for the clip can be the upstanding wall members or the additional wall members of the trunking as defined above.

The fixing elements may further comprise a separate support channel with edge walls between which clips may be resiliently held. In such an instance it is preferred in use for such a support channel to be held between and by the out-turned upper edges of the additional walls on the trunking base.

Moreover, the channel preferably possesses, running along its length, upwardly extending locating and engaging members (e.g ribs of various heights and profiles) and the clips include on their undersurfaces projections adapted to locate and secure the clips in the support channel interengaging with such rib members.

In yet a further aspect the invention consists in a shroud member for a bus bar assembly within a synthetic polymeric trunking, the shroud member comprising a central cover portion, stepped down margin portions, and retaining configuration whereby the cover may be held above and spaced from the busbars.

The retaining configuration at the ends of the stepped down portions of the shroud or cover may on the one side be a simple retaining lip, capable of fitting over suitable projections in the trunking (for example those upstanding channel walls, as discussed in more detail below) and on the other hand terminate in a snap engagement configuration with downwardly inclined lead surface.

In addition to the above three aspects of the invention, namely the embodiments of modified trunking, the novel clip and optional support channel, and the shroud or cover member (each of which can be used in assemblies independently of the others), the invention further extends to combinations of the above elements.

In particular, the invention extends to a combination of the trunking as defined, more especially trunking of the type possessing channel shaped walls with out-turned lips on each element of the channel and a succession of clips spaced along the trunking and held within the two such walls with the channels defined by their flat serpentine convolutions upwardly open to receive and grip busbars. The preferred features of the clip and of the trunking are as defined above. In the assembly it will be found advantageous if the convolutions on the clip match in position other reinforcing and stabilizing structure of the base, such as conventional upstanding walls, which can be used, for example, to clip the flat outer faces of a double convolution, or to locate the flat outer face of a single convolution.

Likewise, the invention extends to a combination of (a) the trunking as defined, more especially trunking of the type with only laterally outer out-turned edges on the upstanding channel wall and with additional inner walls with laterally out-turned edges, with (b) the support channel as above located between and held by the out-turned edges of the additional walls, and (c) a succession of clips spaced along and resiliently held with the support channels with the channels defined by their flat serpentine convolutions upwardly open to receive busbars. Again, it envisages that the upwardly extending locating and engaging members on the support channel are engaged for retention with the clip undersurface projections.

The invention of course further extends to such a combination of trunking and clips (and optional support channel) in which one or more busbars are pressed into and held by the flat convolutions of the clips.

The invention still further extends to an assembly in which the bus bars in the above combination are covered by the cover or shroud as defined above. More especially it is envisaged that this cover or shroud shall fit over the upstanding walls. The environment permits the shroud to be held by a upturned lip on one wall, and to click over a lead in surface on the outer channel portion of the other wall.

In such an assembly it is envisaged that screw fixing may be applied at relatively wide intervals.

It is further envisaged that the assembly may include one or more switch boxes located within the trunk, such boxes having base flanges extending along the ducting away from the base and and held beneath the cover or shroud member.

The invention will be further described with reference to the accompanying drawings, in which: Figure 1 is a transverse section through a trunking and busbar assembly; Figs 2a, 2b and 2c are sections through component parts of another embodiment of trunking and bus-bar assembly; Fig, 3 shows the component parts of Figs. 2a, 2b and 2c assembled together with connector members to illustrate the use of the assembly, and Fig. 4 shows a detail of assembly of a switch housing to the trunking and bus bar assemblies of Fig. 1 or 3.

The trunking and busbar assembly of Fig. 1 is in the form of a construction of uniform cross section and indefinite length. It comprises two main portions namely a trunking construction 1, similar to known trunking constructions, and an internal busbar fixing and shrouding assembly 2.

The trunking construction 1 itself comes in four readily assembled parts, namely an integral base and dividing walls 3, a main cover 4, and two side covers 5 and 6.

The base portion extends as a generally planar profile of indefinite length with symmetrically arranged elongate fixing and strengthening projections mostly located to project internally of the trunking construction. In more detail, these projections comprise successively 11 integral elements namely: (a) An outermost clasping rib 7, flat at the outside surface 7a and internally hooked at the top edge at 7b.

(b) A rib 8 of lesser projection, formed at the top with an arrow shape.

(c) A double leaf wall generally indicated at 9 and described in more detail below.

(d) An upstanding channel defined between two closely spaced walls 10 and 11, each wall with out turned lips 10a and 11a respectively: (e) Another rib, 12, identical with rib 8.

(f) A central rib, 13, identical with rib 8, and (g), (h), (i), (j) and (k) structures identical to features (e), (d), (c), (b) and (a) respectively.

Externally the base has minor strengthening ribs 14 and 15 extending downwards as a continuation of the clasping ribs 7 respectively. It further possesses a like minor rib 16 extending downwards as a continuation of central rib 13. Two other such strengthening ribs 17 and 18 underly part of the base just outward of the doubleleaf wall portion.

Each such doubleleaved wall portion comprises leaves such as 19a and 19b which jointly terminate in an outwardly stepped channel shaped configuration 20 the side walls 21 of which are inwardly inclined.

The main cover 4 is generally planar and possesses at each side a fixing channel 22, with its outer wall 23 of smaller projection than the inner wall 24. This inner wall terminates in a fixing configuration with tapered surface 24a and retaining face 24b. Thus, when the main cover is pushed onto the tapered tops of the upstanding walls the tapered surface 24a slides down an adjacent inclined side wall 21 of channel configuration 20 to clip under the outward step of the double leaved wall.

Each side cover 5 and 6 is configured similarly to the side edge of the main cover so as to be attachable to the double-leafed of the base. As shown, it fixes in the same fashion with its respective channel shaped configuration, with inclined wall 25a sliding into place down the stepped portion.

At its lower edge each side wall comprises a further channel configuration 26. This is defined internally of the smooth outer face 27, and comprises a retaining lip 28 with an inclined surface 29 and retaining edge 30.

This slides over the internally hooked top edge 7g of the rib 7 as described above, so that, as shown, the side wall is fixed both at the top and the bottom.

The type of chambered construction is generally well known, and permits of electrical or fiber optic cables or the like such as printed circuits and bus bars to extend along within the chambers in isolation and in electrical insulation from one another. Indeed, by suitable use of bridge pieces (not shown) the base piece shown can be further connected to a like parallel base piece to form trunking of any desired depth.

Attention is drawn to the channel shape 10, 11 extending along the base of the main portion between the two double retaining walls. This modification of the trunking as described in more detail below is particularly adapted to retain on the one hand suitably shaped clips holding bus bars and on the other hand a shroud member which fits over the whole clip and bus bar assembly for safety purposes.

The bus bar fixing and shrouding assembly 2 then comprises a plurality of spaced and added polymeric clips 30, three parallel busbars 31, 32 and 33 which are asymmetrically held by the clips, and a shrouding cover 34 covering the whole of the bus bar and clip assembly.

The clips 30 are of small width, and although somewhat stiff are flexible enough that they can be pressed inward and then resiliently held at each end under a portion of the outwardly turned lip 11, 11a of the channel configurations 10, 11 on the base. It will be appreciated that when fixing this clip the bus bars are not present. There are three gaps 35, 36, 37 extending within the serpentine structure of each clip 30 and these provide the necessary length wise resilience to allow the clip to be manipulated into place as shown.

As shown, however, it is envisaged that intermediate portions 38 of each clip shall fit snugly between the upstanding projections 12, 13, so that additional security of assembly is achieved. If desired, moreover, another of the serpentine convolutions 39 of the clip 30 can abut a further projection 12 as shown.

An array of such clips 30 is placed at desired spacings along the bases of the trunking 1. Electrical busbars, e.g. copper strip of a size to fit within the clips as shown is then pressed into each available gap 35,36,37, which by the inherent friction of the material hold the busbars 31,32,33 in the desired straight parallel and spaced configuration. Thus, since the clips 30 can be placed at any desired location, any part of the bus bar conductive surfaces is theoretically available for the incorporation of switches or light fitments at each desired position along the trunking.

It will be appreciated by a man skilled in the art that the cover can be readily removed to permit an electrical socket or like unit to be incorporated.

Nonetheless, it is desirable to cover the busbars so that there is no risk of electric shock when the operative is dismantling the system or changing the position of a socket. For this purpose the cover 34, of synthetic polymeric material and of indefinite length, is shaped with a shroud top portion 43, sidewalls 44, and marginal portions 45 themselves downwardly and inwardly configured at 46 and 47 as shown. In the embodiment shown, marginal portion 46 is configured to form a distinct retaining recess. This portion is placed over one or other of the outwardly turned lips 10a, 11a of the channel configuration 10,11, but need not be secured. The other marginal portion 47 can carry a click detent configuration 48, with a lead-in surface 49 as shown, which can be pressed into place so as to click over the outwardly turned edge 10a, 11a of the other channel portion. To give additional security, it is envisaged that the shroud portion 34 shall at intervals be provided with a fixing screw 50. We have found that preferably such screws are applied at the side with the click detent.

Thus, an operative who wishes to gain access to the bus bars and install for example a socket need only remove the top or main cover 4, and thereafter such relatively few fixing screws 50 as may be encountered.

When these relatively few fixing screws 50 are removed the shroud 34 can be manipulated back over the lips 10a, 11a of the respective channel, and taken out to expose the busbars in their spaced clips.

A second embodiment of busbar assembly is shown in Figs. 2a and 2b and 2c.

In Fig 2a the trunking profile 1 is identical with that shown in Fig. 1 except for a central region of the base 3 between the respective channels defined by walls 10,11 in each case. The identical portions are therefore numbered as in Fig. 1.

The channel base 3 is shown slightly depressed at 100. Extending upwards from the depression, at equal distances from the notional central axis of the base are additional walls 101, 102 each with a respective outwardly turned retaining lip 101a, 102a.

A busbar support channel 103 is located in thespace between walls 101, 102, its defining channel walls 104 being outwardly and then downwardly extending at 105, 106 to terminate in a retaining bead 107 with the usual inclined lead-in surface whereby the bead 107 can engage lips 101a, 102a to assemble the channel 103 to the trunking. Channel 103 of course extends indefinitely along the trunking.

Within channel 103 are four upward projections. The outer pair 108, 109 project almost to the top of the channel 103 and are cruciform in cross section to exhibit lateral fitment ribs 108a and 108b, and 109a and 109b. Projections 108, 109 are symmetrically arranged about the notional centre line of the channel -103. The inner, lower, pair of projections 110, 111 are displaced slightly to one side of this line.

Fig. 2a shows the trunking and channel 103 assembled; Fig 2b shows the support channel 103 separately.

Fig. 2c shows a flexible fixing clip 112. Such clips are pressed at intervals into support channel 103. Each clip 112 is of a serpentine nature with flat upper surfaces 113, 114 separating upwardly open deep channels 115, 116, 117 each dimensioned to accept a busbar 118, 119 or 120 and hold it by friction. Surface 113 is slightly wider than surface 114, so that the outer busbars 118, 120 are not equispaced about the central busbar 119.

From the underside of flat surface positions 113, 114 extend minor internal walls 121, 122 each terminating in an outwardly turned lip 121a. 122a.

Opposite each lip 121a, 122a there is a retaining shoulder 115a, 117a on the respective channel walls 115, 117. These features jointly provide inter-engagement with channel 103.

Resilient clips 112 fit into channel 103 at intervals between the channel-defining walls 104. Each clip is retained by lips 115a, 121a scatching on ribs 108a and 108b, and lips 117a, 122a similarly catching against lateral ribs 109a and 109b. Channels 115 and 117 locate against the end walls 104 and channel 116, at its lowest part, between projections 110, 111. The position of channel 103 on assembly is shown in dotted lines in Fig. 2c.

Fig. 3a shows the complete assembly of busbars 118, 119, 120 and trunking 1 with however a shrouding cover 34 (see Fig. 1) omitted for clarity. Since the three busbars 118, 119, 120, while firmly supported are exposed (once shroud 34 is removed) along their lengths between occasional clips 112 three connectors 124, 125, 126 located in their support 127 beneath housing 128 (and not per se forming part of the present invention) can be installed, e.g. as part of a switch or at an internal corner, wherever desired.

Figure 4 shows a switch box 130 which can be used with either of the above embodiments of trunking and bus bar assembly. It is a generally square deep tray construction with access at 130a for connectors e.g.

connectors 124, 125, 126 (Fig. 3) in electrical contact with the underlying bus bars. We have found that in accordance with one feature of the invention a more secure fixing, and an additional safeguard against electric shock, can be achieved by base flange member 131 and an opposed counterpart member (not shown) on the opposite side. In use, flanges 131 are designed to fit beneath the fixing shroud 34 without separate metal screws being used for this purpose in the close proximity of the switch except optionally for a more or less adjacent shroud fixing screw 50.

Thus, in either embodiment of the invention, removal of the main trunking cover 4 displays a safety shroud 34 which is (optionally) secured by only a small number of fixing screws 50 and which abuts and secures the switch or like casing. Removal of this shroud involves only the removal of the small number, if any of screws 50 and prising-off shroud against the click detent. The busbars, themselves firmly secured by the serpentine clip of Fig. 1 or Figs 2a, 2b, 2c, are then exposed for further installation of switches or the like as necessary.

Claims (7)

CLAIMS:

1. A fixing element suitable for use in attaching busbars to a synthetic polymeric trunking, in the form of a separate support channel with edge walls between which clips may be resiliently held.

2. A fixing element as claimed in claim 1 in which the support channel possesses, running along its length, upwardly extending locating and engaging members.

3. The combination of the support channel as claimed in claim 1 or 2 and a succession of fixing clips each having a generally serpentine nature at least some of the convolutions of which possess flat facing surfaces spaced apart by an amount to hold a bus bar, the clips being spaced along and resiliently held within the support channels with clip channels as defined by their flat serpentine convolutions upwardly open to receive busbars.

4. The combination as claimed in claim 3 with the upwardly extending locating and engaging members on the support channel said members being engaged for retention with interengaging projections at the respective clip under surfaces which are adapted to locate and secure the clip to the support channel.

5. The combination as claimed in claim 3 or 4 such that three busbars may be held within the flat serpentine convolutions of the clips.

6. The combination as claimed in claim 5 in which the clips are each asymmetrical to define convolutions whereby a pair of bus bars may be held at mutual spacing different from their spacing in relation to the third bus bar.

7. The combination claimed in any of claims 3 to 6 with one or more busbars pressed into and held by the flat convolutions of the clips.