The invention relates to a casing system for laying": electrical supply and/or signal conductors along the outer surfaces of walls, said casing system comprising as. ^' its principal component a casing of insulating material with at least two longitudinal cavities for accomodating the conductors.

Such casing systems are known in a multitude of variations and are being used to an increasing extent instead of or supplementary to the more traditional forms of fixed electric supply systems in buildings, such as insulated wires drawn through embedded or exposed metal or plastics tubes, or special installation cables for outward mounting on walls and the like.

The utility of casing systems of the kind referred to depends very much on the amount of work, and particularly skilled work, required for mounting the casing system on one or more walls of a room in a neat manner, for wiring the casing system and for mounting and connecting up installation components, such as wall sockets or other electrical connectors, in selected positions, and also on the flexibility in selecting such positions, and on the safety against abusive and hazardous tampering by non-skilled persons.

It is the object of the invention to provide a casing system of the kind referred to, which is optimized in respect of all the factors mentioned above.

With this object in view, according to the invention, a casing system of the kind referred to comprises pre-fabricated unitary, permanently closed profiled casing sections of a variety of fixed lengths with built-in conductors, each such casing section being provided with a number of built-in access modules distributed over the length of the section and each providing access for the touch and creep proof connection of outer conductors or installation components from the front side of the casing to the built-in conduc¬ tors, the casing system further comprising sliding cover sections profiled to engage with the profile of the casing sections and

adapted to be secured to the wall in positions to over-lap and completely cover the gaps between two adjacent casing sections or between a casing sect-ion and an adjacent end section or corner section having a profile equal to that of the casing section for the sliding engagement with a cover section.

In the use of this system, it will always be possible, when the length of wall to be covered is known, to determine the optimum combination of available casing ^' section lengths, and it is then a very simple job to secure these to the wall, while at the same time placing the required number of sliding cover sections in engagement with the profile of the casing sections. In this manner it becomes possible, without cutting or in any other way adapting the parts as manufactured and delivered, to establish casings running from corner to corner or from corner to door frame along one or more walls of a room. Usually the casings will be placed as floor or ceiling skirt¬ ings or alongside existing floor or ceiling skirtings. Casings meeting at an inner or outer corner may be interconnected through corner sections. Casings running along the floor and the ceiling respectively may be interconnected by means of casings of the same kind as those running along the floor and the ceiling, or through simple triangular or flat tubings accomodating insulated conductors for inerconncting the conductors in the floor and ceiling casings.

After the casings have been secured to the walls, the wiring must be completed by establishing electrical connection with external conductors, and between the built-in conductors of adjacent casing sections to the extent this has not already been accomplished in the mounting of the casings, as will later be explained. Where such additional wiring is required, the sliding cover sections will be pushed aside so as to expose the gaps between the casing sections. The interconnection of the ends of the built-in conductors may require some basic skill of an electrician, but may be performed easily and quickly, and this work may even be further facilitated by providing the built-in conductors with suitable terminals, as will later be explained.

After the mounting of the casings and the wiring have been comple¬ ted, the system is ready for the mounting of installation

components, such as wall sockets or other electrical connectors at the location of any one of the access modules, which may e.g. be distributed along the casing sections at a spacing of 1 m or less. The mounting of installation components is an extremely simple operation, which can be performed without hazard - even if the built-in conductors happen, by negligence, to be live - because it does not involve any manipulation of the built-in conductors, but these are on the contrary, with a safety margin, outside the reach of the operator. For the same reason, the access modules at any time not in use are perfectly safe. The moving of an installation compo¬ nent from the location of one access module to that of another is an equally simple operation, so that the system is very flexible for adaptation to changing installation needs.

A further advantage of the invention is that, because the casing sections are profiled elements which remain closed and intact from the moment they are manufactured till the time when the installation on the spot of use has been completed, the casing sections can be made with a relatively feeble cross section and will still have a satisfactory mechanical strength and rigidity in all handling steps to which they are subjected on their way. The consumption of raw materials for the production can therefore be kept low, and owing to their sli ness, the casing sections, when mounted in a room, will be little obtrusive and may even have a decorative effect.

The invention will now be described in further detail with reference to the accompanying drawings, in which

Fig. 1 is a perspective illustration of a casing section, a corner section, and a sliding cover section, by means of which these can be connected with each other, in accordance with one embodiment of the invention,

Fig. 2 shows a similar casing section with one non-used access module and another module made ready for the mounting of an installation component,

Fig. 3 is a ^" front view of a double wall socket adapted td be mounted on the casing section of Fig. 2,

Fig. 4 a perspective rear view of the wall socket of Fig. 3,

Fig. 5 a diagrammatic perspective transparent view of the casing section of Fig. 2 with built-in conductors and contact legs of an installation component mounted on the casing section,

Fig. 6 illustrates the mounting of a contact piece on a conductor adapted to be built into the casing section of Fig. 5,

Fig. 7 is a cross section through the same casing section and two holding plugs for insertion through slots in the rear wall of the casing section,

Fig. 8 is a corresponding partial section with the holding plug inserted,

Fig. 9 a fragmentary rear view of the casing section in the area of the cross section of Fig. 7,

Fig. 10 is a top view of a casing workpiece for use in the making of a casing section according to a further embodiment of the invention,

Fig. 11 is a front perspective view of same,

Fig. 12 is a top view of a front piece for use in connection with the workpiece of Figs. 10 and 11,

Fig. 13 is a rear view of the front piece of Fig. 12,

Fig. 14 is-a top view of a rear piece for use together with the front piece of Figs. 12 and 13,

Fig. 15 is a front view of same,

Fig. 16 is a longitudinal section through a casing section according to the invention made from the parts of Fig. 10-15, with an outer conductor connected to a built-in conductor, the section being taken along a line corresponding to the line XVI-XVI in Fig. 13,

Fig. 17 is a part section taken along the line XVII-XVII in Fig. 16,

Fig. 18 is a perspective view of the'end of a casing section and a terminal plug belonging thereto, the figure il¬ lustrating the parts in a stage of the production be- fore the terminal plug has been secured in position,

Fig. 19 is a perspective view of the parts of Fig. 18 after the terminal plug has been secured in position,

Fig. 20 shows a sinuous spring that may be used for impart¬ ing increased elasticity to the built-in conductors, as illustrated in Fig. 18,

Fig. 21 is a front view on a larger scale of a contact bush- ing forming part of the terminal plug of Fig. 18,

Fig. 22 is a top view of same,

Fig. 23 is an end view of same, as viewed from the right,

Fig. 24 is a view corresponding to Fig. 21, but with a built-in conductor and a connecting conductor clamped in the contact bushing,

Fig. 25 is a perspective view of a connector section that may be used for interconnecting two adjacent casing sections,

Fig. 26 is a sliding cover section for use in connection

with the connector section of Fig. 23,

Fig. 27 is a perspective view of an end section,

Fig. 28 is a perspective view of a transition section, that may be used for establishing connection between an end section or a corner section and a corner casing of triangular cross section,

Fig. 29 is a front view of a casing length built up from two end or corner sections, one casing section and two sliding covers.

In Fig. 1, 1 is a casing section, which is the main component of a casing system according to one embodiment of the invention. The casing section 1 consists of insulating material, such as an extru¬ ded plastics material. The casing section is profiled as shown and contains three longitudinal cavities 2, 3 and 4. The casing section is unitary, i.e. in one piece, and is thus permanently closed. The cavities 2 and 4 serve to accomodate built-in conductors (not shown in Fig. 1), that may be non-insulated hard copper conductors. The cavity 3 is reserved for the passage of screws for fastening to a wall and also provides a separation of the passages 2 and 4.

The profile of the casing section 1 comprises two grooves 5 and 6 serving as sliding guides for sliding cover sections. Such a sliding cover section is shown at 7 and serves to connect the casing section 1 with a corner section 8, the legs of which have grooves 9 and 10 corresponding to the grooves 5 and 6, and therebetween an open space for the accomodation of insulated conductors 12 which may be connec¬ ted with the built-in conductors in the cavities 2 and 4 by means well known in the art, but preferably by means of a terminal plug fastened in the mouths of the cavities 2-4. One form of such a terminal plug will be described later with reference to Figs. 18-24. By means of a corner section as described two casing sections meeting at a corner may be connected with each other by sliding the sliding cover sections into axial abutment with the inner end faces of the corner section and then fastening each sliding cover section to the wall by means of a screw 13. The figure illustrates that

insulated conductors 12 can be passed from casing section to casing section meeting at a corner, or from either up through an opening 14 to which a profiled tube may be connected for enclosing insulated conductors connecting a casing section at the floor with a casing section at the ceiling or with network supply wires. If two casing sections are to be connected at a corner without connection of their built-in connectors to external conductors, a corner section without an opening 14 may be used. At an outer corner a corner section may be used having a configuration substantially laterally reversed with respect to that illustrated.

Sliding cover sections corresponding to the section 7, though with omission of the incision 15 at one corner - to provide space for the upper wall of the corner section - can be used for interconnecting aligned casing sections so as to enclose the gap between the sect¬ ions at an overlap.

By means of the described elements in a moderate assortment it is possible to equip a room with concealed fixed supply conductors along one or more, or conceivably all walls, not only at the floor and/or ceiling but also in intermediate positions where the casings may e.g. form boundaries of panels or fields. It is likewise possib¬ le to arrange the casings vertically from floor to ceiling.

Each casing section is provided, in a number of positions distribu¬ ted over its length, with access modules, of which various embodi¬ ments will be described in the following, and thereby it becomes possible in a simple manner to mount and connect up fixed installa¬ tion components, such as wall sockets, light plugs or other electri- cal connectors, in any one or several of a large number of posi¬ tions, or to move about previously mounted components if the need arises.

In the embodiment illustrated in Figs. 2-9, a cylindrical contact piece 18, 19 is clamped on the built-in conductors 16, 17, as illustrated in Fig. 7, and, if deemed necessary, consolidated by soldering, in each of the access module positions. In one mode of producing the casing section as a commercial product, the contact pieces are clamped on the conductors 16, 17 before these are slid

into the cavities 2, 4, e.g. by applying suction to the ends of the cavities remote from those, at which the conductors are introduced. One or more of the contact pieces may thereafter be held in correct position by means of forked holding plugs 20, 21, which are introdu- ced through slots in the rear wall of the casing section to engage annular grooves 22, 23 of the cylindrical contact pieces 18, 19, as illustrated in Figs. 7, 8 and 9.

In each access module position, a fixed installation component- may be mounted. In Figs. 3 and 4 such a component is illustrated in the form of a double wall socket 24 with switches 25, 26. The contact sleeves 27, 28 of the wall socket are connected with rearwardly projecting forked contact legs 29, which are arranged at an inclina¬ tion and can be pushed through inclined slots 31, 32 in the front wall of the casing section to be clamped around the cylindrical contact pieces 18, 19, whereafter the wall socket is fastened to the wall by means of a screw 33, which is passed through a hole 34 of the casing section in the region of the intermediate cavity 3.

When the access module is not to be used, the slots 31, 32 are covered by a sliding cover 35 which is fastened to the wall by means of a screw 36 passing through the hole 34, as illustrated to the right in Fig. 2.

When the access module is to be used, the sliding cover 35 is pushed aside, as illustrated to the left in Fig. 2. It is fastened in its new position by passing the screw through another hole, which is shown at 37 for the access module to the right. Hereafter the wall socket 24 can be mounted as previously described.

Figs. 10 and 11 illustrate a stage in the production of a casing section according to. a modified embodiment of the invention. These figures show a casing length corresponding to the casing section 1 of Fig. 1, the grooves 5 and 6 having been omitted for simplicity of illustration. In the areas 38 and 39 where access modules are to be provided, the front and rear wall portions of the casing have been cut away, as by milling, to a depth such as to expose the longitudi¬ nal cavities 2, 3 and 4. Hereby it becomes possible, in the manufac¬ turing process, to apply contact pieces to the built-in conductors

after these have been placed in the cavities, and consequently contact pieces may be used, which cannot, or can only with difficul¬ ty be slid longitudinally through the cavities- so as to arrive in correct positions for take-off from the front ,side of the casing. After such contact pieces have been mounted in correct positions on the conductors in the cut-away areas, these areas can be covered by means of a front piece and a rear piece which are clamped and sealed together against the left-over rib-like portions of the casing structure so as to permanently close the profile. By suitably constructing the front piece, various forms of touch and creep free access from the front side of the casing to the built-in conductors may be established.

One example of a casing section, that can suitably be manufactured by the method just described is illustrated in Figs. 12-16.

In this example, the front piece 40, Figs. 12 and 13, is constructed on its rear side with short pegs 41a for engaging in positioning holes 42 on the front side of the casing section at the sides of the cut-away area 38, Fig. 10, and long pegs 41b which can be inserted through holes 43 of the casing section and holes 44 of the rear piece 45 and can then be heat sealed on the rear side of the rear piece 45. The casing section is now permanently closed in the cut-away areas, and the front piece 40 and the rear piece 45 form integrated portions of the front wall and the rear wall of the casing section.

Before the front piece 40 and the rear piece 45 can be clamped and sealed together as described, an electrically conducting clamping member 47, Figs. 16 and 17, is clamped on each of the conductors. The clamping member 47 has a clamping screw 48 for clamping the clamping member on the conductor 46, and besides a clamping screw 49 with an insulated head 50 which in the finally assembled state can clamp the stripped-off end 51 of an insulated outer wire 52 in a clamping passage 53 formed in the member 47.

When the front piece 40 and the rear piece 45 are clamped together against the casing ribs, the conductors 46 are nested in insulating bucks 54 on the inner side of the rear piece 45, while the

insulating head 50 of the clamping screw 49 penetrates into a hole 54 in the front piece 40 surrounded by a collar 55. In this position two inclined access passages 56 provided, in the _. front piece 40 merge into the clamping passages 53 of the clamping members 47.

When all access modules of a casing section have been completed in the manner described, the casing section is ready for sale.

When a casing system comprising such casing sections has been mounted on a wall, an installation component with insulated attach¬ ment wire bits 52 can be set up at the location of any one of the access modules by stripping off the insulation from the ends 51 of the wires, introducing these through the access passages 56 into the clamping passages 53 of the clamping member 47 and tightening the clamping screws 49, whereafter the installation component can be fastened to the wall across the access module.

Figs. 18 and 19 illustrate a suitable manner in which a casing section can be closed at its ends by means of terminal plugs, reference being also made to Figs. 20-24.

The terminal plug illustrated in these figures comprises an insula¬ ting housing 57, which has a front plate 58 and three rearwardly extending legs 59, 60 and 61 fitting in the front ends of the longitudinal passages 2, 3 and 4, respectively. The housing 57 has two longitudinal passages 62 and 63 extending from the front end of the housing 57 through the legs 59 and 61, respectively. Each of the passages 62 and 63 serves to receive a contact bushing 64 and 65, respectively. The upper contact bushing 64 is illustrated in Figs. 21-23, and the lower contact bushing 65 is identical, though inver¬ ted with respect to a horizontal plane. At its front end, the bushing 64 has an upwardly protruding edge portion 66 adapted to engage with a stop face (not shown) in the passage 62. The front half of the interior of the bushing 64 is subdivided by means of a partition 67 so as to form two vertical flat slots 68 and 69. Clamping screws 70 and 71 are provided for clamping the denuded end of a connecting conductor 72 against the partition 67, and the end of the built-in conductor 16 against the opposed inner wall of the bushing 64, respectively, as illustrated in Fig. 24.

The middle leg 60 of the insulating housing 57 has a hole 73 for receiving a screw 74, by means of which, upon insertion of the

: terminal plug into the end. of the casing section, the material of the leg can be expanded so as to hold the terminal plug firmly in position by friction.

In the embodiment illustrated, the built-in conductors are construc¬ ted with elasticized portions 75 formed by passing each conductor in a zig-zag path through staggered holes 76 of a sinuous spring 77, e.g. consisting of beryllium-bronze. The provision of such elastici¬ zed portions is advantageous in the case of casing sections of great length, because the built-in conductors may be subjected to substan¬ tial tensile stress if the casing section is bent during transporta¬ tion or handling. In casing sections of shorter length, elasticizied portions are not required.

If, in the manufacturing process, the conductors 16 and 17, with contact pieces 18,19 secured thereto in correct positions for the access modules, are slid into and through the longitudinal cavities 2 and 4 from one end of the casing section, as described with reference to the embodiment of Figs. 2-9, the conductors may at that end beforehand be passed through the slots 68 and clamped in the bushings 64, 65 by directly applying a screwdriver to the heads of the clamping screws 71. The same procedure may be used at the other end of the casing section, if the conductors are constructed with elasticized portions 75, so that the conductor ends can be pulled out from the mouths of the cavities of the casing section, while the tightening of the clamping screws 71 is taking place. Otherwise the clamping screws 71 will be accessible after insertion of the termi- nal plug through holes 78 in the front wall of the casing section and holes 79 in the insulating housing 57.

Further holes 80 and 81 in the front wall of the casing section and in the insulating housing 57, respectively, are provided for provi- ding access to the heads of the clamping screws 70, by means of which connecting conductors 71 can be clamped in the slots 69 when a casing system is being set up in a room with use of casing sections with terminal plugs of the kind described.

When the terminal plugs of the kind described are used in connection with the embodiment of Fis. 2-9, these terminal plugs may suffice for holding the built-in conductors 16,17 in a position such that the contact pieces 18,19 are correctly positioned behind the access slots 31,32, the length of the contact pieces being so chosen that their position relatively to the slots is not critical. However, for casing sections of a relatively great length it is recommendable to use holding plugs 20,21, as described with reference to Figs. 7-9, for holding at least one pair of contact pieces 18,19 in accurate position.

Fig. 25 illustrates a connector section 82 which may be used at one or more junctions between adjacent casing sections. The connec¬ tor section 82 consists of a short block 83 of insulating material with embedded strips of electrically conducting material extending in the form of pegs 84 at both ends of the block. When using the connector section, the pegs 84 are introduced int _^ the clamping slots 69 of the terminal plugs at the adjoining ends of the two casing sections, and are clamped therein by means of the clamping screws 70. A sliding cover section 85 is then slid into position so as to cover the block 83 at an overlap, and is fastened to the wall by means of a screw 86 passing through a hole 87 of the block.

Alternatively the built-in conductors of adjacent casing sections can be interconnected by means of loose insulated conductors which are clamped in the slots 69, as previously described with reference to Fig. 24.

Fig. 27 shows an end section 88 for use in cases where an end of a casing length along a wall is not to be connected to further parts of the casing system. As will be seen, the end section 88 is very similar to the corner section 8 shown in Fig. 1, with the exception that the second leg of the corner section has been replaced by a flat wall 89, which is flush with the front wall of a sliding cover (not shown) corresponding to the sliding cover 7 in Fig. 1. 90 is a screw by means of which the end section can be fastened to a wall.

At its top the end section 88 has a square opening (corresponding to the opening 14 in Fig. 1) which is closed by means of a plug 91. In

this form the end section is used, when the built-in conductors of the adjacent casing section are not to be connected to external conductors. If, on the. contrary, such a connection is to be establi¬ shed, the plug 91 may be removed, and a transition section may be connected to the square opening. One form of a transition section is shown in Fig. 28. It comprises a lower portion 93 of square cross- section, and an upper portion 94 of triangular cross-section for receiving the end of a triangular tube or casing fitting in the corner of a room. In such a triangular tube or casing insulated conductors may be placed, which are connected to the built-in conductors of the adjacent casing section and serve to connect these e.g. with the built-in conductors in casing sections mounted at the ceiling, or with a network supply switch.

The transition section of Fig. 28 can also be used in connection with the corner section 8 of Fig. 1. It will be obvious to those skilled in the art that other forms of transition sections can be used, if it is e.g. desired to use a flat tube or casing for the external conductors instead of a triangular one.

Example.

Fig. 29 illustrates how a casing length, e.g. from one corner of a room to another, can be built up from two end or corner sections 8, 88, one casing section 1 and two sliding covers 7.

The various dimensions are indicated in Fig. 29 as follows:

a = length of wall to be covered, b = length of casing section, c = length of end section or one leg of corner section, d = length of gap between casing section and end or cover section, e = length of overlap between casing section and sliding cover, f = length of sliding cover.

In the example, the following conditions apply:

c = 50 mm, d = minimum 50 mm, - e = minimum 50 mm. - ^■ • ^{* '} \ "-

For varying lengths of wall a to be covered, a casing syste can now be composed from standard elements in accordance with the following table:

Length of wall Length of casing Length of sliding section cover

a b f

0.7 - 0.9 500 mm 250 mm

0.9 - 1.2 m 500 mm 400 mm

1.2 - 1.7 m 1000 mm 400 mm

1.7 - 2.2 m 1500 mm 400 mm

2.2 - 2.7 m 2000 mm 400 mm

2.7 - 3.2 m 2500 mm 400 mm

3.2 - 3.7 tu ^¬ 3000 mm 400 mm

3.7 - 4.2 rn 3500 mm 400 mm

4.2 - 4.7 m 4000 mm 400 mm

4.7 - 5.2 m 4500 mm 400 mm

5.2 - 5.7 m 5000 mm 400 mm

5.7 - 6.2 m 5500 mm 400 mm

6.2 - 6.7 m 6000 mm 400 mm

Similarly, if two casing sections 1 are interconnected by means of the connector section 82 of Fig. 25 with cover 85 of Fig. 26, wall lengths from 6.7-12.7 m can be covered, and with three interconnec- ted casing sections wall lengths up to 18.7 m, etc., and similar tables can be set up for determining the appropriate composition in each individual case.

Conversely, should a consumer wish to build up a casing system from casing sections not exceeding a length of, say 3000 mm, wall lenghts from 3.7-6.7 m could be covered by using two casing sections 1 within the range of 500 mm-3000 mm interconnected by means of a connector section 82, etc.

While the invention has been described with particular reference to its application to two wire electrical supply systems, it will readily be understood, that the invention is equally applicable to three wire electrical supply systems, or to signal wire or combined supply and signal wire systems.