GB1602864A

GB1602864A - Electrical ducting

Info

Publication number: GB1602864A
Application number: GB1827678A
Authority: GB
Original assignee: Legrand SA
Current assignee: Legrand SA
Priority date: 1977-05-06
Filing date: 1978-05-08
Publication date: 1981-11-18
Also published as: DE2819812A1; DE2819812C2; FR2390073A1; BE866570A; FR2390073B1

Description

(54) IMPROVEMENTS RELATING TO ELECTRICAL DUCTING (71) We, LEGRAND S A, a body corporate organised and existing under the laws of France, of 128, Avenue du Marechal de Lattre de Tassigny, 87000 Limoges, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates generally to electrical ducting and more particularly to mounting supports for mounting electrical components in electrical ducting.

Such ducting which is usually made of insulating synthetic material can accommodate various electrical components, such as switches or terminal blocks, and also electric cables for supplying current to such components.

According to the invention there is provided a mounting support, for mounting and supporting an electrical component in ducting having longitudinally extending ribs formed as right-angled flanges projecting from the inner face of a base of the ducting, the mounting support comprising a median bar having means whereby the electrical component can be secured thereto and at each end of the median bar, a foot-piece to be engaged with one of said ribs, each footpiece being formed by two co-operating resilient shanks comprising an inner shank and an outer shank.

The mounting support can be clipped onto the ribs of the ducting and have the electrical component secured thereto by said means which preferably comprise screw threaded apertures in the median bar.

Such a mounting support can advantageously optionally be engaged so that it extends either transversely of the ducting from one of the ribs on the base of the ducting to another, or longitudinally of the ducting on only one of the ribs.

Preferably for ducting of the kind having two side-walls on inwardly turned portions of which a cover may be fitted, the depth of the mounting support in relation to that of the side-walls is such that when an electrical component is mounted by the mounting support and covers of the ducting are in position on said side-walls, there exists between the component, including any decorative facing plates that may be fitted thereon, and the edge portions of said sidewalls with which said cover is in contact, a space sufficient to enable the covers to extend beneath edge portions of the electrical component.

The advantages of this arrangement will be more readily appreciated if it is recalled that in previously proposed ducting of this kind, it is necessary, when fitting an electrical component, either to provide the cover of the ducting with a local recess having the exact contour of the electrical component, which involves a careful and lengthy operation, or to fit the cover edge-to-edge with the electrical component. This latter alternative involves cutting out part of the cover in a precise manner and also does not take account of the differential thermal expansion that inevitably occurs, during use, between the cover and the ducting on to which it is fitted.

Thus cutting away portions of the cover is avoided and all that is needed is a roughly formed opening at the end, which is covered by the electrical component by its decorative facing element which masks such opening from view. Said opening may be of such size that, when the covers are fitted there is sufficient clearance to ensure that any differential thermal expansion that may occur is subsequently automatically absorbed.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is an elevation of a mounting support according to the invention; Figure 2 is a side view taken in the direction of arrow II of Figure 1; Figure 3 is a plan view taken in the direction of arrow III of Figure 1; Figure 4 is a perspective view illustrating one possible use of the mounting support of Figures 1 to 3 in a ducting, before an electrical component that the mounting support is to mount has been secured thereto; Figure 5 is a view similar to that of Figure 4 after the electrical component has been secured to the mounting support; Figure 6 is a sectional view of a detail taken on line VI-VI of Figure 5; Figure 7 is a perspective view illustrating another use of the mounting of Figure 1 to 3 in a ducting; Figures 8A and 8B are plan views of parts of mounting supports according to the invention and to be fitted end-to-end, these Figures showing how such mounting supports can latch with one another; Figure 9 is a perspective view illustrating the use of a mounting support according to the invention in another kind of ducting; Figures 10 and 11 are views of parts of two further kinds of ducting in which a mounting support according to the invention can be used; Figure 12 is a perspective view of part of a ducting with which can be associated a covering element; Figure 13 is a partial sectional view on line XIII-XIII of Figure 12; and Figure 14 is a perspective view of a modified form of covering element to that shown in Figure 13.

Referrin first to Figures 4 and 5, ducting 10, in which a mounting support according to the invention can be used, takes the form of an extruded member of insulating synthetic material having a base 11 and two side-walls 12.

Proiecting from the base 11 are two lonai- tudinally extending ribs 13 which, in the example illustrated in Figures 4 and 5, are formed integral with the base 11 and each have two oppositely extending flanges 14 which project at right-angles to the part of the rib which extends from the base 11, the flanges 14 extending parallel 'o the base 11.

Across the flanges 14, each rib 13 has a width D1.

Between the inwardly directed flange 14 of one of the ribs 13 and the inwardly directed flange on the other rib 13 there is a transverse gap that has a width D2.

The side-walls 12, which are parallel to one another, have inwardly directed flanges 15 at their free edges, the facing edge-portions of which flanges 15 are so formed as to constitute receiving means for the longitudinal edges of a cover 16 shown in Figure 5.

In the arrangement illustrated in Figures 4 and 5, the inner edges of the flanges 15 are formed to present channels 18 extending the entire length of the ductina, which channels 18 receive dependent edges 20 at the lonaitudinal edges of the cover 16.

The arrangement is such that when the cover 16 is fitted with its dependent edges 20 engaged in the channels 18 of the ducting 10, the cover 16 lies flush with the outer surfaces of the flanges 15 of the side-walls 12 of the ducting, since free edges of the flanges 15 lie at a height H1 measured from the inner surface of the base 11, which height H1 is equal to the depth of the sidewalls 12 minus the thickness of the cover 16, (see Figure 5).

The ducting 10 is designed to accommodate an electrical component designated by the reference numeral 22 in Figures 4 and 5, as well as accommodating the electric cables necessary for supplying said component with current.

Such electrical component does not itself form part of the invention and will not therefore be described in detail.

In the example illustrated, the component is a rocker switch.

Generally, such an electrical component will comprise a body 23, which has to be accessible to the user, connected to a fixing plate 24.

The fixing plate 24, shown only diagrammatically in Figure 4, has various openings formed therein including holes 25 for receiving screws for enabling the fixing plate to be secured to a mounting support.

As shown in Figure 5, the electrical component 22 is usually completed by a decorative facing plate 26 which has in its central zone an opening 27 for receiving the body 23 and which is provided with tabs for latching it onto the plate 24 carrying the body 23 (not shown in detail in the drawins).

For example, and as illustrated in Figures 4 and 5, the arrangement is such that the width L1 of the decorative facing plate 25 is substantially equal to that of the cover 16 for the duct 10.

In practice however, the width L1 of the decorative facing plate 26 may, if desired, be greater than that of the cover 16 so as to ensure that the full width of the cover 16 is covered.

Thus, such a decorative facing plate 26 can be substituted locally for the cover 16 so as to close the ducting 10 or to form, itself, a means for closing the gap between two spaced apart lengths of cover 16.

As can be seen from Figures 1 to 3, a mounting support 30, which can be readily attached to the ribs 13 to mount and support in the ducting 10 an electrical component such as the component 22 referred to above, comprises a median bar 31, provided at its upper surface with tapped holes 32 forming fixing means suitable for securing with the aid of screws not illustrated the electrical component 22, and at each end of said median bar 31, a foot-piece 33 comprising at least one shank to be resiiienflv fitted onto a or a respective one of the ribs 13 of the ducting 10.

In the illustrated example, each foot-piece 33 comprises two co-operating shanks, com prising an inner shank 34 and an outer shank 35.

The inner shanks 34 extend substantially perpendicular to the median bar 31.

The outer shanks 35, beginning at the median bar 31, slope away from the shanks 34.

The shanks 34 and 55 of each foot-piece 33 each have on their respective transverse mutually opposite faces and at a distance from their free ends, recesses 37 defining shoulders to co-operate by engaging beneath the oppositely directed flanges 14 of one of ribs 13 of the ducting 10.

The distance separating the side-walls of a recess 37 in one of the shanks 34 from that of the recess in the adjacent shank 35 measured in a direction parallel to the longitudinal extent of the median bar 31 is substantially equal to the distance D1 defined above in connection with the flanges 14 of a rib 13.

Each recess 37 is preceded, in the direction of engagement with rib 13, by an inclined bearing face 38.

As can be best seen in Figure 2, the shanks 34 and 35 of a foot-piece 33 are offset from each other in the transverse direction and perpendictilarly to the longitudinal extent of the median bar 31 and each has in its face opposite the corresponding face of the other and at a distance from its free end a recess 40 forming a shoulder to co-operate with the opposite recess by engaging beneath the opposite directed flanges 14 of one of the ribs 13 of the ducting 10.

The distance separating the side-wall of the recess 40 in one of the shanks 34 from that of the recess in the other shank 35 is substantially equal to the above-mentioned distance D1.

Also, as in the case of the previously mentioned recesses, each recess 40 is preceded by an inclined bearing face 41.

Furthermore, in the embodiment illustrated and for reasons that will appear hereinafter, each of the inner shanks 34 of each foot-piece 33 has, at a distance from its free end, a recess 42 forming a retaining shoulder on its face which is towards the inner shank 34 at the other end of the median bar 31.

The distance separating the side-walls of these retaining shoulders 42, from one of the shanks 34 to the pother, is designated D3 in Figure 1.

As in the previous cases, each retaining shoulder 42 is preceded by an inclined bearing face 43.

The free ends of the various shanks 34 and 35 are at the same level in the embodiment illustrated.

Thus, in the case of ducting 10 of the kind illustrated in Figures 4 and 5, the mounting support 30 is located transversely in the ducting 10 with the inclined bearing faces 38 of the support 30 engaged with the flanges 14 of the ribs 13 of the ducting 10, pressure is then applied to the support to cause elastic deformation of the shanks 34 and 35, until the retaining shoulders 37 of the shanks can move beyond the flanges 14 of the ribs 13.

The support 30 is thus clipped onto the ribs 13 of the ducting 10 and this operation can be carried out very easily and very rapidly.

On completion of this clipping action, the free ends of the shanks 34 and 35 of the support 30 may bear against the base 14 of the ducting 10.

Alternatively, the ends of the shanks may remain at a distance from the base of the ducting, the support 30 being retained in relation to the base because of the slope of the outer shanks 35.

Two supports 30 can in this way be arranged transversely in the ducting 10 and parallel to each other at a distance corresponding to the corresponding dimension of the plate 24 of the electrical component 22 to be secured.

The centre-to-centre distance of the tapped holes 32 formed in the surface of the median bar of one of the supports 30 will correspond to those normally used for the holes 25 in the plate 24 of the component 22.

In practice, the number and location of such tapped holes 32 are such as to correspond to the number and location of the holes formed in several different types of apparatus.

The component 22 is then attached, with the aid of screws, not shown, extending through the holes 25 in its plate 24, to the two supports 30 secured in the ducting 10.

The decorative facing plate 26 of the component 22 is then secured to the plate 24 of the apparatus using methods known per se and therefore not described here-Figure 5.

The depth H2 of the support 30 (Figure 1) in relation to the depth H1 of the side-walls 12 of the ducting 10, defined above, is so selected in practice that when a component 22 is secured in this way to the supports 30 and the cover 16 associated with the ducting 10 is itself connected to the ducting, there exists between the apparatus 22 and the decorative facting plate 26 thereof, and the edge portions of the side-walls 12 and the end faces of the channels 18 formed in the flanges 15 of the side-walls, a space having a depth e2 which is greater than the thickness el of the cover 16 and which therefore enables this cover 16 to be readily fitted below the decorative facing plate 26, as illustrated in Figure 6.

The cover 16 can then simply be cut to the require length in a relatively unprecise manner, and furthermore this cover 16 is afforded free play, particularly to allow for thermal expansion, below the decorative facing plate 26, as illustrated in broken lines in Figure 6.

In an alternative method of use illustrated in Figure 7, one of the supports 30 is fitted in the ducting 10, extending, not transversely as previously, but longitudinally, and it is clipped onto a single rib 13 of the ducting by means of the retaining shoulders 40 of each of the foot-pieces 33, using a procedure similar to that described above.

It is thus possible either to cater for items of apparatus having holes 25 with different centre-to-centre distances, or to position such items of apparatus longitudinally in relation to the ducting 10 and not transversely as previously, particularly in the case where the ducting 10 extends vertically.

When each support 30 is positioned in this way on a single rib 13 of the ducting 10, it may be required to interconnect such supports 30 in pairs along the rib.

This possibility is illustrated in Figures 8A and 8B.

For this purpose each of the outer shanks 35 of the support 30 is provided with clip means suitable for coupling it to the outer shank of another similar support 30.

In the arrangement illustrated, such clip means are constituted by a rounded projection 45 provided on the inner face of the outer shank 35, i.e. on that face of this shank that, parallel to the median bar 31, faces the inner shank 34 of the same foot-piece.

When two adjacent supports 30 are brought together in the direction indicated by the arrows F in Figure 8A, the corresponding projections 45 overlap and engage in a resilient manner, and the supports become clipped together and their corresponding foot-pieces become nested one within the other, because of the dispositions of these foot-pieces and, in particular the slope of their outer shank and the transverse offsetting of the inner and outer shanks forming each foot-piece (Figure 8B).

The holes 32 permit a choice in the predetermined spacing El, E2 or E3, in the example illustrated, for the component 22 concerned.

Figure 9 illustrates the use of the supports 30 in the case where the ducting 10 is provided at its base 11 with ribs 13 with each rib having only one right-angled flange 14, the flange 14 of the one rib extending in a direction opposite to that of the flange on the other rib.

By a procedure similar to that described above with reference to Figure 4, the support 30 can be engaged transversely in the ducting 10 until, due to elastic deformation of its inner shanks 34, the retaining shoulders 42 on these shanks engage beneath the flanges 14 of the ribs 13, the distance D3 that separates the side-walls above the retaining shoulders 42 being substantially equal to that between the free edges of the right-angled flanges 14 of the ribs 13.

The retaining shoulders 42 thus co-operate with the right-angled flanges 14 of two separate ribs 13.

As before, engagement of a support 30 in the ducting 10 can be limited by the contact of the free ends of these shanks with the base of this ducting.

However, and as illustrated, this engagement is in practice limited by support shoulders 421 which extend parallel to the retaining shoulders 42 at a distance thereabove that is substantially equal to the thickness of the flanges 14 of the ribs 13, the shoulders 42 and 421 of a shank 34 forming opposite sides of one and the same slot.

In the foregoing, it has been assumed that the channels 18 of the flanges 15 of the ducting 10 are simply of U-shaped cross-section.

However, as shown in Figure 10, such channels can be provided with a retaining beading 50 to co-operate with a rounded clip-in projection 51 provided for the purpose on the corresponding dependent edge 20 of the cover 16.

In the modified arrangement illustrated in Figure 11, a channel 18 formed in the ducting 10 is inclined throughout its length, and the corresponding dependent edge 20 of the cover 16 is inclined in a complementary manner.

As illustrated in broken lines in Figure 11, it is thus necessary to deform elastically the dependent edges 20 of the cover 16 to be able to fit the cover on the ducting 10, and when the cover returns to its initial con finuration after having been engaged, it is firmly connected to the ducting 10.

Figures 12 to 14 illustrate the case where, for wiring reasons in particular, the ducting 10 has a transverse dimension, L2, from one of its channels 18 to the other, that is greater than the corresponding dimension L1 of the decorative facing plate 26 for the components 22 that are to be housed.

Associated with such ducting is a frontplate 55, forming a covering element to be connected to the ducting to close off a local portion thereof, which front-plate comprises, at least transversely, raised end portions 56 to permit the end portions of two covers 16 to be readily engaged beneath them (Figures 12 and 13) to provide the advantages of a rough cut and possible play as described above, and which comprises, in its central zone 57, at least one cut-away portion 58 through which can be passed the facing portion of a component fitted vertically into the ducting 10.

In the case where, as illustrated, the central zone 57 of such a front-plate 55, when connected to the ducting 10, is located at the same level as the covers 16 flanking the front-plate 55, the decorative facing plate of the apparatus concerned is laid flat on this central zone 57 around the entire cut-away portion 58 (this arrangement not being shown in the drawings).

However, particularly if the level of the central zone 57 of the front plate 55 is higher, the cut-away portion 58 of this central zone may have sufficiently large dimensions to form a frame around such decorative facing plate.

Furthermore, a plurality of recesses 58 may be formed for accommodating a plurality of components side-by-side.

In the modified arrangement illustrated in Figure 14, the raised portion of the component constituted by the front-plate 55 forms a peripheral frame around its central zone 57.

In all cases, such a front-plate 55 is provided with lateral depending edges 60 suitable for engaging the front-plate in the channels 18 of the ducting 10, in the same manner as the depending edges 20 of a cover 16.

Then, the edges may be simple rectilinear ones as described by reference to Figures 1 to 9, or they may be provided with rounded projections, as described by reference to Figure 10, or they may be inclined edges as described by reference to Figure 11.

The invention is not however limited to the embodiments described and illustrated; many other embodiments being possible within the scope of the appended claims for example, as regards the fixing means provided on the median bar of support 30, and/or as regards the shape of the dependent edges of the cover elements and of the front-plates 55.

WHAT WE CLAIM IS:- 1. A mounting support, for mounting and supporting an electrical component in ducting having longitudinally extending ribs formed as right-angled flanges projecting from the inner face of a base of the ducting, the mounting support comprising a median bar having means whereby the electrical component can be secured thereto and at each end of the median bar, a foot-piece to be engaged with one of said ribs, each footpiece being formed by two co-operating resilient shanks comprising an inner shank and an outer shank.

2. A mounting support according to claim 1, in which the inner shank of each foot-piece has, spaced from its free end, a retaining shoulder to engage beneath the ri1Tht-angled flange of a respective one of two separate ribs.

3. A mounting support according to claim 1 or claim 2, in which the two shanks of each foot-piece have on mutually facing surfaces and spaced from their free ends, retaining shoulders to co-operate by engaging beneath the right-angled flanges of the same rib with the median bar extending perpendicular to the rib.

4. A mounting support according to any one of claims 1 to 3, in which the two shanks of each foot-piece are offset transversely from each other in a direction perpendicular to the longitudinal extent of the median bar, and the shanks each have on their mutually facing surfaces and spaced from the free ends, a recess forming a retaining shoulder to co-operate by engaging the right-angled flanges of one of the ribs with the median bar extending parallel to said rib.

5. A mounting support according to any one of claims 1 to 4, in which each retaining shoulder is preceded by an inclined bearing face when considered in the direction of movement to engage the shanks with the rib or ribs.

6. A mounting support according to any one of claims 1 to 5, in which the inner shanks extend substantially perpendicular to the median bar, each outer shank is inclined relatively to the respective inner shank and, starting at said median bar, diverges from the respective inner shank.

7. A mounting support according to any one of claims 1 to 6, in which at least one of the outer shanks is provided with clip means to clip such shank onto an outer shank of another similar mounting support engaged on the same rib.

8. A mounting support according to claim 7, in which the clip means comprises a projection from the inner surface of the outer shank.

9. A mounting support according to any one of claims 1 to 8 for ducting of the kind having two side-walls on inwardly turned edge portions of which a cover may be fitted, in which the depth of the mounting support in relation to that of the side-walls is such that when an electrical component is mounted by the mounting support and covers of the ducting are in position on said side-walls, there exists between the component, including any decorative facing plates that may be fitted thereon, and the edge portions of said sidewalls with which said cover is in contact, a space sufficient to enable the covers to extend beneath edge portions of the electrical component.

10. A mounting support, for mounting and supporting an electrical component in ducting having longitudinally extending ribs

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. front-plate 55, the decorative facing plate of the apparatus concerned is laid flat on this central zone 57 around the entire cut-away portion 58 (this arrangement not being shown in the drawings). However, particularly if the level of the central zone 57 of the front plate 55 is higher, the cut-away portion 58 of this central zone may have sufficiently large dimensions to form a frame around such decorative facing plate. Furthermore, a plurality of recesses 58 may be formed for accommodating a plurality of components side-by-side. In the modified arrangement illustrated in Figure 14, the raised portion of the component constituted by the front-plate 55 forms a peripheral frame around its central zone 57. In all cases, such a front-plate 55 is provided with lateral depending edges 60 suitable for engaging the front-plate in the channels 18 of the ducting 10, in the same manner as the depending edges 20 of a cover 16. Then, the edges may be simple rectilinear ones as described by reference to Figures 1 to 9, or they may be provided with rounded projections, as described by reference to Figure 10, or they may be inclined edges as described by reference to Figure 11. The invention is not however limited to the embodiments described and illustrated; many other embodiments being possible within the scope of the appended claims for example, as regards the fixing means provided on the median bar of support 30, and/or as regards the shape of the dependent edges of the cover elements and of the front-plates 55. WHAT WE CLAIM IS:-

1. A mounting support, for mounting and supporting an electrical component in ducting having longitudinally extending ribs formed as right-angled flanges projecting from the inner face of a base of the ducting, the mounting support comprising a median bar having means whereby the electrical component can be secured thereto and at each end of the median bar, a foot-piece to be engaged with one of said ribs, each footpiece being formed by two co-operating resilient shanks comprising an inner shank and an outer shank.

formed as right-angled flanges projecting from the inner face of the base of the ducting, substantially as hereinbefore described and illustrated with reference to Figures 1 to 9 of the accompanying drawings.