GB2301490A

GB2301490A - Cable entry system for an item of road furniture

Info

Publication number: GB2301490A
Application number: GB9607275A
Authority: GB
Inventors: Paul Buckley
Original assignee: FOREST CITY SIGNS Ltd
Current assignee: FOREST CITY SIGNS Ltd
Priority date: 1996-04-09
Filing date: 1996-04-09
Publication date: 1996-12-04
Anticipated expiration: 2016-04-09
Also published as: GB9607275D0; GB2301490B

Abstract

A cable entry system for an item of road furniture comprises a duct assembly (22) through which a cable can pass into an below ground enclosure (10) intended to be set in concrete. The assembly (22) has an adapter (40) by which it is sealingly attached at an entry aperture of the enclosure (10). A cable sealing gland (32) is carried on the duct assembly to allow entry of and to seal with a mains supply cable (50). The concrete is cast such that the gland (32) remains outside of the concrete in free ground so facilitating replacement of the cable.

Description

CABLE ENTRY SYSTEM FOR AN ITEM OF ROAD FURNITURE The present invention relates to an electrical feed system for an item of road furniture.

Many items of road furniture are comprise a foundation structure and a plastic superstructure. The foundation structure comprises a metal enclosure which is, in use, buried in the ground, the superstructure being mounted upon it to project above ground level.

Typically, the foundation structure is installed by digging a hole at the required place, such that the enclosure can be placed in the hole with a clear space surrounding it. The clear space is subsequently filled with concrete to fix the foundation structure permanently in place.

In many cases, an electrical feed cable must be provided to power, for example, one or more lights in the foundation structure or in the superstructure.

Conventionally, a cable is installed before the concrete is filled around the foundation structure. It is passed through a hole in a side wall of the enclosure, a sealing gland being provided in the hole to resist ingress of water and other contaminants into the foundation structure.

It will be appreciated that, in this arrangement, the cable and the sealing gland are buried in concrete.

The result of this is that particularly difficult excavations must be carried out in the event that the cable must be replaced. Such excavations are not only costly: they may also have a long-term effect upon the security of the foundations.

It is an aim of the invention to provide a foundation structure having a cable entry system for an item of road furniture which does not compromise convenience of installation and strength when compared with the above described known arrangement, but which facilitates removal and replacement of an electrical fee cable.

According to a first aspect of the invention there is provided a foundation structure for an item of road furniture comprising an enclosure to be buried in the ground, the enclosure having a wall through which is formed a cable entry hole, the foundation structure further comprising a duct member extending outwardly from the entry hole, and a sealing gland carried on the duct member remote from the enclosure, whereby a cable can be passed through the sealing gland and the duct member to enter the enclosure, and the duct member being of sufficient length such that the sealing gland projects outside of a concrete formation cast around the foundation member on installation.

By this arrangement, access to the cable and the sealing gland can be obtained through excavation of the ground surrounding the concrete, without the need to excavate the concrete itself. This is of substantial advantage.

Preferably, there is carried on the duct a fitting by means of which it can be sealingly secured to the enclosure. In this manner, the duct and gland can be provided as an assembly separate from the enclosure.

The duct member may typically be formed from a length of semi-rigid plastics tube.

The foundation structure of the first aspect of the invention may typically be used as a foundation structure for an illuminated traffic bollard.

In another of its aspects, the invention provides a duct assembly for use in construction of an item of road furniture comprising a length of tubing, an adapter carried of the length of tubing which can be secured to a foundation enclosure to resist ingress of contaminants, and a further adapter by means of which a cable gland assembly is sealing secured to the tubing.

In yet another aspect of the invention, there is provided a method of constructing a foundation structure for an item of road furniture in which a duct assembly is attached to an enclosure, the duct assembly having a cable gland separated from the enclosure by a length of tubing, the enclosure and the duct assembly is located in an excavation and a quantity of concrete is cast around the enclosure, the concrete being disposed such that at least the cable gland projects from the concrete, an electrical feed cable being installed to pass through the duct assembly into the enclosure.

An embodiment of the invention will now be described in detail by way of example with reference to the accompanying drawings in which: Figure 1 is a cross-sectional view of part of a foundation structure being a preferred embodiment of the invention; and Figure 2 shows more generally the foundation structure of Figure 1 with a traffic bollard mounted on it.

With reference to the drawings, a foundation structure for a traffic bollard comprises an enclosure 10 fabricated from steel sheets. A mounting plate 12 is pivotally carried on the enclosure 10, this being adapted to carry a superstructure for a traffic bollard 14.

Within the enclosure 10 there is provided a lighting assembly 16 disposed to direct light upwardly through an aperture 18 in the mounting plate 12 into the superstructure of the bollard 14. (It will be noted that the superstructure is in an opened condition so as to offer maintenance access.) In use, the enclosure 10 is placed into a previously excavated hole, such that a clear space surrounds it.

Concrete is then poured into the space such that the enclosure 10 is secured firmly in place.

Insofar as it has been described above, the present embodiment is conventional in structure.

It will be understood that the lighting assembly 16 must be provided with a supply of electrical power. This is typically obtained from an underground armoured mains electricity cable. Provision must be made whereby the cable can enter the enclosure 10 while maintaining a seal which is resistant to penetration of water and other contaminants into the enclosure 10.

An entry aperture 20 is provided in a sheet of the enclosure to permit entry of the electrical cable. This may be formed at one of a plurality of alternative "punch out" regions, such as shown at 20'. A duct assembly 22 is secured to the enclosure 10 at the aperture 20. The duct assembly 22 will be described below in greater detail, with particular reference to Figure 2.

The duct assembly comprises a length of semi-rigid plastics tubing 24. In this particular embodiment, this tubing is < *** diameter and material *** > tube, coloured black to comply with normal colour coding conventions for underground services. Additionally the tubing 24 must be sufficiently strong to resist crushing by concrete cast around it.

The duct assembly further comprises a first adapter 26 is secured to an outer end of the tube 24. This comprises a sleeve having a first length which has a plain internal bore which is a close fit with the external diameter of the tube 24. A permanent, impermeable seal is formed between the tube 24 and the first length, as shown at 28. A second length of the sleeve projects beyond the outer end of the tube 24. The second length, indicated at 30, is internally threaded.

In this example, a 25mm thread is provided, this being a standard in the industry.

A cable gland assembly 32 is secured to the first adapter 26. The cable gland assembly 32, which is, in this case, a conventional component, has an externally threaded spigot 34 which is screwed into the thread of the first adapter 26. A sealing washer 36 is disposed between the first adapter 26 and a shoulder of the cable gland assembly 32 to provide a highly impermeable seal between them. As will be recognised by those skilled in the art, the cable gland assembly 32 will allow a cable to pass through itself into the tube 24, while forming a seal with an outer surface of the cable to resist ingress of water into the tube 24.

The duct assembly has, at an inner end of the tube 24, a second adapter 40. The second adapter 40 comprises a sleeve which has a first portion which has a plain internal bore. A permanent, impermeable seal is formed between the first portion and an end portion of the tube 24, as shown at 32.

The second adapter 40 further comprises a threaded spigot 44 which projects form the sleeve away from the tube 24. The threaded spigot 44 has a 25mm external thread. On this, is carried a sealing washer 46 and a nut 48.

For use, nut 48 is removed from the threaded spigot 44 of the second adapter. The spigot 44 is then passed through the entry aperture 20 of the enclosure 10 such that the washer 46 comes into contact with the wass surrounding the entry aperture. The nut 48 which is then screwed onto the spigot 44 and tightened to securely and sealingly fasten the duct assembly to the enclosure 10.

(This operation may be carried out before or after the enclosure 10 is placed in an excavation.) A cable (shown in phantom at 50) is then passed though the duct assembly into the enclosure 10, and the cable gland assembly 32 is tightened to form a seal. A concrete base for the enclosure 10 may then be cast, provided that a barrier is first erected to protect the gland assembly 32 from the concrete.

It will be seen that this results in the enclosure 10 being cast into a concrete base in a manner suitable for providing a firm foundation structure. A particular advantage is that the cable gland assemble 32 is outside of the cast concrete surround, in free ground. Thus, should a subsequent need to replace the cable arise, only free ground need be excavated. There is no need to break into the cast concrete surround. This represents a substantial labour saving, and ensures the continued integrity of the foundation structure.

For any particular application, the length of the tube 24 can be selected with consideration to the thickness of the concrete to be cast.

It will be appreciated that the particular construction described is not central to the invention, and that many variations are possible.

Claims

CLAIMS.

1. A foundation structure for an item of road furniture comprising an enclosure to be buried in the ground and surrounded by cast concrete, the enclosure having a wall through which is formed a cable entry hole, the foundation structure further comprising a duct assembly extending outwardly from the entry hole, and a sealing gland carried on the duct member remote from the enclosure, whereby a cable can be passed through the sealing gland and the duct member to enter the enclosure, and the duct member being of sufficient length such that the sealing gland projects outside of a concrete formation cast around the foundation member on installation.

2. A foundation structure according to claim 1 in which there is carried on the duct assembly as adapter by means of which it can be sealingly secured to the enclosure.

3. A foundation structure according to claim 1 or claim 2 in which the duct assembly comprises a length of semirigid plastics tube.

4. A foundation member according to any preceding claim in which the duct assembly comprises an adapter to which the sealing gland may be threadingly connected.

5. A foundation structure substantially as described herein with reference to the accompanying drawings.

6. A foundation structure according to any preceding claim on which is mounted a traffic bollard.

7. A duct assembly for use in construction of an item of road furniture comprising a length of tubing, an adapter carried of the length of tubing which can be secured to a foundation enclosure to resist ingress of contaminants, and a further adapter by means of which a cable gland assembly is sealing secured to the tubing.

8. A method of constructing a foundation structure for an item of road furniture substantially as herein described with reference to the accompanying drawings.

8. A duct assembly according to claim 7 in which the tubing is sufficiently crush resistant and corrosion resistant to withstand being buried in concrete.

9. A duct assembly substantially as herein described with reference to the accompanying drawings.

10. A method of constructing a foundation structure for an item of road furniture in which a duct assembly is attached to an enclosure, the duct assembly having a cable gland separated from the enclosure by a length of tubing, the enclosure and the duct assembly is located in an excavation and a quantity of concrete is cast around the enclosure, the concrete being disposed such that at least the cable gland projects from the concrete, an electrical feed cable being installed to pass through the duct assembly into the enclosure.

Amendments to the claims have been filed as follows 6. A foundation structure according to any preceding claim on which is mounted a traffic bollard.

7. A method of constructing a foundation structure for an item of road furniture in which a duct assembly is attached to an enclosure, the duct assembly having a cable gland separated from the enclosure by a length of tubing, the enclosure and the duct assembly is located in an excavation and a quantity of concrete is cast around the enclosure, the concrete being disposed such that at least the cable gland projects from the concrete, an electrical feed cable being installed to pass through the duct assembly into the enclosure.