GB2258092A - Folding blank forming accessory box or cable trunking. - Google Patents

Abstract

A plastics container for electrical cabling may be embodied as trunking (figs. 2, 8), a connector for lengths of trunking or an accessory box (fig. 10) for items of electrical equipment, and is provided in a flat form with predefined fold lines (74, 75) enabling the container to be formed. The container walls have predefined areas providing access to the interior of the container, formed either by weakened areas which may easily be removed or by preformed apertures (15) optionally provided with removable covers. Trunking may be provided with one or more dividing walls (83) and optionally a lid (82). Alternatively the folded blank may form a box section. Trunking may be formed with male and female ends for interconnection. <IMAGE>

Description

SYSTEM AND COMPONENT PARTS FOR ROUTING ELECTRICAL CABLES The present invention relates to a system, and the component parts thereof, for routing electrical cables and mounting electrical equipment, particularly using trunking made from plastics material, e.g. P.V.C.

Trunking is generally used in the electrical industry to contain electric wires and cables. It is known, for instance from GB-A-2205005 to provide trunking made of plastics material which is supplied coiled in a substantially flat condition. There are provided a plurality of longitudinal fold-lines, so that the substantially flat material may be folded to give a box-section suitable for use as trunking.

In one embodiment of the above mentioned patent specification, the trunking is supplied with three longitudinal fold-lines so that when it is assembled, a rectangular cross-section is obtained, all four sides being of the same original substantially flat member.

In another preferred embodiment, the trunking is supplied with two longitudinal fold-lines so that when it is assembled, a generally U-Shaped channel is formed. There is further provided a cover which fits onto the channel to close the trunking. Thus, in this embodiment, there are two coils which must be provided: one on which the flat member to form the U-channel is coiled, and the other on which the over is coiled.

Also, in our patent application GB-A-2241385 we disclose plastics trunking comprising a plurality of sunstanz ally flat elongate member of plastics material, wherein each elongate member has a longitudinal foldline defining two elongate wall sections and comprises connection means adapted to interlock with the connection means of another member, whereby to attach the members one to another.

In a preferred embodiment, two identical elongate members lock together to give a trunking with a rectangular cross-section. In this embodiment it is only necessary to have one type of original member, while this does not need to be inconveniently wide.

The original substantially flat members forming this type of trunking are preferably manufactured by an extrusion process and this has the advantage that only one extrusion die is needed which need not be large.

In certain applications, such as computer installations, there are situations in which a number of cables are required to follow the same route but a degree of physical separation between cables is an advantage. This would arise if for instance cables carrying a mains electricity supply were to follow the same route as cables carrying low voltage data signals.

The risk of interference in the data cables caused by the mains cables can be markedly reduced by physically separating these cables. Clearly it would be possible to achieve this by using one trunking for each set of cables but this requires twice the installation work of a single trunking and may not be very efficient use of space if all of the cables to follow a particular route would in fact physically fit into a single trunking.

It is also known to provide moulded plastic boxes for mounting items of electrical equipment such as mains outlet sockets or light switches on walls for use, in the form of open rectangular boxes comprising a rectangular base and four side walls. A light switch, mains outlet socket or other item of electrical equipment is attached to the box, typically by way of screws, forming the sixth side of the box and thus forming a closed box. The size and shape of the base of the box and the depth of the box provided by the sides may vary depending on the particular item of electrical equipment to be mounted. For instance a double mains outlet socket requires a rectangular box which is relatively deep, while a light switch requires a square box which is relatively not so deep.

Such boxes are generally manufactured in their final usable state. That is the boxes are moulded with the sides standing perpendicular from the base and joined at the corners of the box. This has the disadvantage that the boxes are bulky to package, and a relatively large space is required to store a relatively small quantity of boxes.

The present invention provides a plastics container for containing electrical cabling comprising a substantially flat member having at least one fold line defining a plurality of wall sections and wherein there is at least one area at a predetermined position in at least one of said wall sections adapted to provide access to the interior of the container through the wall section.

A preferred embodiment of the present invention is a modification of the arrangement described in our two earlier cases mentioned above and provides channelling or trunking having areas at predetermined positions along the length of at least one elongate wall section for providing access to the interior of the trunking.

Preferably, the areas are weakened areas which are still integral with the remainder of the wall section. Alternatively, holes may be formed in the wall section which then may be filled or closed by snap fitting closures.

The intention of the weakened areas is to provide access to the interior of the trunking when an area is removed in such a way as to leave an opening the surround of which is neatly finished. This is not only better from a cosmetic point of view but also enables neater joints to be made.

The present invention may also be embodied in a moulded connector for creating junctions between lengths of trunking as an initially flat member with fold lines to form a upstanding side walls. Preferably the cover is also part of the same moulding. At least one of the side walls of the connector is preferably provided with areas to provide access to the interior of the connector.

The present invention also preferably provides a different modification of the trunking described in the two previous applications mentioned above and provides means for inter-engagement between lengths of trunking.

Trunking formed according to this invention may incorporate either or both of the features mentioned above as features of this invention.

The present invention also provides plastics trunking comprising a substantially flat elongate member having at least one longitudinal fold line defining a plurality of wall sections and a further elongate member adapted to form an internal dividing wall and wherein the first mentioned elongate member comprises means in one of said wall sections for supporting said further elongate member.

This trunking is particularly useful in the above discussed applications where it is advantageous to separate cables following the same route. The trunking and the wall are provided in a flat state and the trunking is formed of one or more sections folded along their length. The trunking has provision for supporting the internal wall, and this wall may be used for some or all of the length of trunking, as required by the particular application. The cables to be separated are placed on different sides of the internal wall and thus a degree of physical separation is guaranteed even if the trunking is subject to movement.

The trunking according to this aspect of the invention therefore provides advantages in terms of ease of installation and efficient use of space.

The divided trunking described above is preferably formed of a U-shaped section into which the dividing wall and cables are put before the attachment of a cover section. However the trunking may be formed in other configurations, for instance two L-shaped sections may be joined to form a rectangular section, or a single section having three fold lines may form all four external walls of a rectangular trunking.

The present invention also envisaged trunking incorporating both of the features of the invention discussed above (ie - providing acces to the interior of the trunking and providing a dividing wall).

A variation of the divided trunking is a cable tray having a plurality of dividing walls each as mentioned above. This is similar to the U-shaped trunking with a divider described above except that the its is comparatively wide and there is provision for accepting a plurality of walls or dividers. Such a cable tray may be provided with or without a cover.

Such a cable tray is useful in applications where there is a very large number of cables in close proximity which are advantageously separated from each other. This may not be for electrical interference reasons as described above but simply'for neatness and ease of access. In such a situation a cable tray could be attached to a wall, floor or shelf, dividers installed and the cables routed in the channels between the dividers as required.

It will be apparent that a divider as described may be used in conjunction with either or both of the first two described aspects of the invention.

In the system of the present invention there is also provided an electrical mounting box comprising a substantially flat plastics moulding having a base portion and side portions each having a first edge attached by way of a hinge to a respective side of the base portion, and each having, at the edges adjacent said first edge, interconnection means whereby the side portions may be locked together when folded about said first side.

The side and/or base portions of such a box may be provided with apertures adapted to accept trunking for instance according to the aspects of the invention described above.

In order that the present invention be more readily understood, embodiments thereof will now be described by way of example with reference to the accompanying drawings, in which: Fig. I shows a part of an extrusion according to a first aspect of the present invention; Fig. 2 shows a part of a channel constructed from the extrusion shown in Fig. 1; Fig. 3 shows a plan view of a moulding of a Tpiece connector according to the present invention; Fig. 4 shows an alternative connector according to the present invention; Fig. 5 is an end view of an extrusion to form trunking according to a second aspect of the present invention; Fig. 6 is a perspective view of a part of trunking formed from the extrusion shown in Fig. 5; Fig. 7 shows a cross-sectional view of a generally flat elongate extrusion of plastics material which forms the major section of a third aspect of the invention;; Fig. 8 shows a cross-sectional view of fully assembled trunking of which the extrusion of Fig.7 is the major part; Fig. 9 shows a cross-sectional view of a further embodiment of the invention; and Fig. 10 illustrates an electrical mounting box according to this invention.

Figs. 1 and 2 show a part of an extrusion 10 according to the first aspect of the invention which is provided with a plurality of, in this case two, fold lines 11 forming a base section 12 and side wall sections 14 which, in use, are arranged to be folded along the fold lines 11 to form upstanding side walls as shown in Fig. 2.

Bracing means such as are described in our earlier patent specifications mentioned above may be provided along the fold lines.

One or both of the side wall sections 14 is formed with weakened areas 15 which can be readily removed in use to provide access to the interior of the trunking. The weakened areas may be formed by stamping only part of the way though the thickness of the wall section to form a section which may be easily knocked out. Alternatively, complete holes may be stamped which are then provided with snap-fit covers.

The base is shown as being unaltered but of course weakened areas could be provided in it also. The base may have an adhesive backing and may be marked for screw fixing to a surface.

Fig. 3 shows a T-piece connector which is arranged to be moulded as an initially flat member 30 with a number of fold lines or hinges 31 which form wall sections 32. The wall sections may be plain or may be provided with weakened area 33 similar to those described in relation to Figs. 1 and 2.

The preferred materials for forming the components of this invention are plastics materials e.g.

PVC of the type described in GB-A-2205005.

The holes or weakened areas can be of any desired shape or size e.g. square, rectangular or circular and the periphery may be formed with a shoulder to improve the rigidity of the joint.

While a T-piece connector has been shown, it will be appreciated that on folding up the side wall sections, holes will be formed in the corners. This can be avoided by moulding a connector whose general shape in plan view is a three or more sided figure without any interior angle around its periphery.

Fig. 4 shows one such connector with integral cover section which allows a T-connection to be made but without leaving gaps at the corners.

As in Fig. 3, the connector of Fig. 4 is initially moulded as a flat member 40. This has fold lines or hinges 41 defining base 42, a first wall 44, two second walls 46 and a cover 45. It will be appreciated that when all of the hinges 41 are folded to define a right angle a connector will be formed having a plan shape the same as that of the base 42, and with three apertures able to accept trunking as indicated by numeral 47.

The two connectors shown in Figs. 3 and 4 each provide for three lengths of trunking to join in a 'T' formation. Other connectors may be formed within the scope of this invention which form junctions between different numbers of lengths of trunking, and/or enable lengths of trunking to meet at angles other than right angles.

Trunking or conduit according to the second aspect of the invention is produced from an extrusion or moulding for instance as shown in Fig. 5. This figure shows the cross-section of a generally flat member 50 with longitudinally extending fold lines 54 which form hinges and define therebetween a base section 51 and wall sections 52 and 53. The outer wall sections 53 of the flat member 50 are formed with mating engaging portions 55 and 56 so that when the member is folded up, the mating portions inter-engage to form a complete box section as illustrated in Fig. 6. The number of wall sections may vary so that rectangular, hexagonal or octagonal sections may be formed.

It is to be noted that in the drawing, the length of the wall section 53 from the outermost hinge 54 to the adjacent edge is only a part e.g. one half, of the width of the base 51 of the trunking so that the interconnection is not at a corner. If desired, the hinges 54 may be provided with bracing means as disclosed in GB-A-2205005.

The trunking according to the second aspect of the invention is produced as finite lengths either by moulding (for short lengths) or by extrusion for longer lengths. In either case but especially for extruded lengths a PVC of the type disclosed in GB-A-2205005 may be used if it is available.

A further feature of this embodiment of the invention is the provision at the ends of the lengths of trunking of engagement means so that two lengths of trunking may engage with each other when butted end to end. The engagement means 60 illustrated in Fig. 6 comprises a simple tongue and groove arrangement but more complicated arrangements such as snap fits are envisaged.

One or more of the wall sections of the trunking according to the second aspect of the invention may be provided with openings at predetermined locations or with weakened portions as in the first aspect of the invention which can be removed to provide access to the interior of the trunking in use. The shape and size of the opening or weakened areas may be chosen to be square, rectangular, circular or any shape depending on the use to which the opening is to be put.

The connector pieces as illustrat in Figs. 3 and 4 may be provided with engagement means such that the trunking according to the second aspect of the invention may be attached thereto in a similar manner to that in which the lengths of trunking are attached one to another.

The embodiment of this invention illustrated in Figs. 7 and 8 provides a plastics trunking which it is possible to divide into two parts by means of an internal wall. The dividing wall provided by this invention is optional in use and the trunking may be used un-divided or divided for all or part of its length.

Referring to Fig. 7 there is shown the crosssection of a generally flat elongate extrusion of plastics material forming the major section of the first embodiment. Section 70 comprises three wall portions 80, 71, 72. Portion 80 is conveniently referred to as the base and portions 71, 72 as side-walls, but this terminology is not intended to limit the invention in any way. Section 70 further comprises hinge 74 between base 80 and side-wall 71 and hinge 75 between base 80 and side-wall 72. In order to assemble the trunking, the strip illustrated in Fig. 7 is folded along hinges 74, 75 in order that side-walls 71, 72 are perpendicular to base 80.

The trunking is provided with bracing means 76, 77. As will be appreciated from Fig. 7, when sidewall 71 is folded up along hinge 74, part 76a fits over part 76b and parts 76a and 76b interlock to retain sidewall 71 perpendicular to base 80. Parts 77a and 77b similarly interlock to retain side-wall 72 perpendicular to base 80. Other embodiments of this invention may utilize different means for retaining the side-walls in position with respect to the base on assembly of the trunking.

Side-walls 71, 72 are provided with interconnection means 78, 79 respectively. These provide for connection to a cover section as will be described in relation to figure 8.

As may be seen in Fig. 7 the trunking of this embodiment is further provided with a groove 73 running along its length. This is illustrated as being in the centre of base 80, although its exact position may be varied according to the intended use of the trunking.

Groove 73 is adapted to receive and support an internal dividing wall within the trunking as will be described below.

Fig. 8 illustrates a cross-sectional view of fully assembled trunking according to this aspect of the invention. The same reference numerals designate the same parts as in Fig. 7. In figure 8 section 70 has been folded along hinges 74, 75 and side-walls 71, 72 are braced in position by bracing means 76, 77 as described above.

As can be seen from Fig. 8, in addition to section 70 the trunking comprises a cover 82 and a dividing wall 83. Cover 82 is also a substantially flat elongate extrusion of plastics material which forms, as shown, the fourth side of the generally rectangular cross-section of the completed trunking. Cover 82 is provided with interconnection means 84, 85 which cooperate with interconnection means 78, 79 as shown to attach cover 82 to section 70.

In other embodiments it is possible to utilize interconnection means having a different shape to that illustrated in Figs. 7 and 8. It is also possible to dispense with one or both of bracing means 76, 77 and rely on the fixing of cover 82 to retain side-walls 71, 72 in position. Further, it is possible to provide all four walls of the trunking as a single extrusion having three fold lines, and interconnection means such as means 78, 84 to attach the two edges together.

Dividing wall 83 is a further substantially flat elongate extrusion of plastics material. Dividing wall 83 is provided with interconnection means 81 which fits into groove 73 in base 80. Interconnection means 81 and groove 73 are adapted to maintain dividing wall 83 perpendicular to base 80 as shown.

Thus in this embodiment the interconnection between the wall 83 and base 80 is provided by a male interconnection means on wall 83 and a female interconnection means on base 80. Wall 83 may alternatively be attached to and supported by base 80 by means of male interconnection means on base 80 and corresponding female interconnection means in wall 83.

In a further alternative the support means on base 80 for wall 83 may be provided only at intervals along the trunking.

The various interconnection means and longitudinal channels described above may be simply extruded into the trunking, which can be formed in any convenient thickness. The extruded section 70 may be formed with fixing screw holes therein or plain, as shown, or may have an adhesive backing.

The extrusions according to this invention are preferably of polyvinylchoride (P.V.C.) which is semirigid with a "memory" for remembering shape. The extrusions can be coiled when not'longitudinally folded or joined together (i.e. when in a substantially flat condition).

The material is advantageously stable at temperatures below 0 C and is resistant to shattering.

A suitable material is commercially available from Plycol (PVC) Limited under the grade reference FC 15/85T and has, approximately, a Cold Fiex temperature of -3"C, a Cold Bend temperature of -25"C and a Tensile Strength of 15.3 MN/m2.

A further suitable material is available from Norsk Hydro Polymers Limited under the grade reference XN 75467 and has, approximately, a maximum Cold Flex temperature of -6 C, a maximum Cold Bend temperature of 2 -20"C, a minimum Tensile Strength of 15.2 MN/m and a nominal Shore A Hardness of 92.

In practice a coil of one of the extrusions according to this embodiment may be formed by producing the appropriate extruded section, cooling the extrusion by a suitable method (e.g. water, air or refrigeration), feeding the extrusion into a set of nip rollers, and winding it into a coil.

When a section of the trunking is required a suitable length of the section may be unrolled from the coil, cut off, straightened (due to the "memory" of the material), and folded to form the basic U-shape. This can then be affixed to the wall or ceiling as required with the open side facing outward to receive e.g.

electrical wires or cables. Lengths of dividing wall if provided are inserted as required and a cover if necessary is finally affixed to complete the trunking.

The embodiment of this invention illustrated in Fig. 9 provides a cable tray made of plastics material, which may be extruded in a similar manner to the embodiments described above, and is preferably made of the same materials as those described above.

The cable tray of this embodiment comprises a major section 90 and dividing walls 95. Section 90 is similar to section 80 in the embodiment of Figs. 7 and 8 and comprises a base 91 having side-walls 92, 93 hinged thereto. Section 90 is provided initially in a substantially flat state and for use side-walls 92, 93 are folded into the positions shown. As can be seen from figure 9, section 90 comprises similar bracing means to those illustrated in Fig. 7 to hold side-walls 92, 93 at the required angle with respect to base 91.

Base 91 is substantially wider than the base of the above embodiment and is provided with a number of longitudinal grooves 94. There are four grooves 94 illustrated in figure 9, but there may be more or less than this number provided as required by the application of the cable tray. There is also provided a number of dividing walls 95 which fit into grooves 94 as shown.

These are similar to the dividing wall of the above embodiment. Because the dividing walls 95 are provided separately from the major section 90, dividing walls 95 may be used in some or all of the grooves 94 for some or all of their length according to the requirements of the particular application.

Fig. 10 illustrates an electrical mounting box according to this invention.

The electrical mounting box illustrated in Fig. 10 may be of similar construction to the connector illustrated in Fig. 4 and comprises a base 101, two side walls 102 and two end walls 103. Initially the plastics moulding forming the box has a substantially flat or planar form as may be seen in the right hand portion of Fig. 10.

At the edge where sides 102, 103 are attached to base 101 hinges are formed which allow the sides to be folded to be perpendicular to the base. The hinges may simply be grooves running between the base and the sides. In order to form the box for use, the first step is to fold the sides to be upright along the hinges.

In order to retain the shape of the box with sides 102, 103 upright with respect to the base 101, there is provided interconnection means between the edges of the sides where the sides meet. This is illustrated in Fig. 10 by the numeral 104 and is shown as a tongue and groove joint. However, the interconnection means may take any appropriate form and is preferably a snap fit.

When all four sides are joined together a rigid box is formed which may be used in the applications as described above. However the boxes according to the preset invention have the advantage that they are easier to store and package than the prior art boxes and they need not be assembled until immediately before use.

Boxes according to this invention may be manufactured having a number of differing shapes, sizes and depths according to the particular intended use. As illustrated in Fig. 10, there are further provided mouldings 105 on end walls 103 which are designed to receive screws attaching an item of electrical equipment to the box. Mouldings 105 may be provided with threaded metal inserts, not shown, into which the screws may be screwed.

The electrical mounting box according to this invention may further be provided with holes in base 101 to allow attachment by way of screws to a wall, for instance, and also with "knock-out" portions in the base which may be removed at the user's choice to allow entry of cables into the box.

Claims (25)

CLAIMS:

1. Plastics container for containing electrical cabling comprising a substantially flat member having at least one fold line defining a plurality of wall sections and wherein there is at least one area at a predetermined position in at least one of said wall sections adapted to provide access to the interior of the container through the wall section.

2. Plastics container according to claim 1 wherein each said at least one area at a predetermined position is a weakened area integral with the wall section and which may be easily removed to provide an aperture giving said access.

3. Plastics container according to claim 1 wherein each said at least one area at a predetermined position is a preformed aperture in the wall section.

4. Plastics container according to claim 3 wherein each said preformed aperture is provided with a closure which fits into and closes said aperture and which may be removed to provide said access.

5. Plastics container according to claim 4 wherein said closures are a snap fit into said apertures.

6. Plastics container according to any of claims 2 to 5 wherein said aperture is adapted to receive the end of a length of electrical trunking.

7. Plastics container according to claim 6 wherein said aperture has a shoulder formed around the periphery thereof.

8. Plastics container according to any of claims 1 to 7 forming trunking wherein said substantially flat member is elongate and said at least one fold line is longitudinal along said elongate member.

9. Plastics trunking according to claim 8 wherein the ends of the elongate member are provided with interengagement means whereby a plurality of lengths of trunking may be joined together end to end.

10. Plastics trunking according to claim 9 wherein the first end of the elongate member is provided with male interengagement means and the second end is provided with corresponding female interengagement means.

11. Plastics trunking according to any of claims 8 to 10 further comprising a further elongate member adapted to form an internal dividing wall and wherein the first mentioned elongate member comprises means in one of said wall sections for supporting said further elongate member.

12. Plastics trunking according to any of claims 8 to 11 comprising a first elongate member having two longitudinal fold lines defining a base section and two wall sections and a second elongate member forming a cover section, the first and second elongate members having interengagement means whereby the cover section may be attached to the first elongate section to form closed trunking having a substantially rectangular cross-section.

13. Plastics trunking according to any of claims 8 to 11 comprising a single elongate member having three longitudinal fold lines defining a base section, two wall sections and a cover section, the longitudinal edges of the elongate section having co-operating interengagement means whereby on folding the elongate member and engaging the interengagement means closed trunking having a sustantially rectangular cross-section is formed.

14. Plastics container according to any one of claims 1 to 7 forming a cable tray wherein said substantially flat member is elongate and comprises two longitudinal fold lines defining a base wall section and two side wall sections and further comprising a plurality of further elongate members adapted to form dividing walls, wherein said base wall section comprises means for supporting said further elongate members.

15. Plastics container according to any one of claims 1 to 7 forming a connector for lengths of electrical trunking, said substantially flat member comprising a base wall section having a plurality of straight edges and a smaller plurality of side wall sections each connected to one edge of said base wall section, there being a fold line between each side wall section and the base wall section such that when the side walls are folded to be at an angle with respect to the base wall section access is provided to the interior of the connector by way of the spaces at the edges of the base wall section not having side wall sections connected thereto.

16. Plastics connector according to claim 15 further comprising a cover member having substantially identical shape to the base wall section.

17. Plastics connector according to claim 16 wherein the cover member is hinged to one of said side wall sections.

18. Plastics container according to any one of claims 1 to 7 forming an electrical mounting box comprising a substantially flat plastics moulding having a base portion and side portions each having a first edge attached b way of a hinge to a respective side of the base portion, and each having, at the edges adjacent said first edge, interconnection means whereby the side portions may be locked together when folded about said first side1 further comprising means adapted to permit an item of electrical equipment to be mounted on said mounting box.

19. An electrical mounting box comprising a substantially flat plastics moulding having a base portion and side portions each having a first edge attached by way of a hinge to a respective side of the base portion, and each having, at the edges adjacent said first edge, interconnection means whereby the side portions may be locked together when folded about said first side.

20. An electrical mounting box as defined in claim 19 in which said base portion is rectangular and the box comprises four side portions.

21. An electrical mounting box as defined in claim 19 or 20 in which an opposing pair of side portions comprises means to receive screws for mounting a cover on said box.

22. Plastics trunking comprising a substantially flat elongate member having at least one longitudinal fold line defining a plurality of wall sections and a further elongate member adapted to form an internal dividing wall and wherein the first mentioned elongate member comprises means in one of said wall sections for supporting said further elongate member.

23. Plastics container for containing electrical cabling substantially as hereinbefore described with reference to the accompanying drawings.

24. Plastics trunking substantially as hereinbefore described with reference to the accompanying drawings.

25. Electrical mounting box substantially as hereinbefore described with reference to the accompanying drawings.