GB2462031A

GB2462031A - Access cover lid for manholes

Info

Publication number: GB2462031A
Application number: GB0919435A
Authority: GB
Inventors: Ronald Francis Clark
Original assignee: CLARKSTEEL HOLDINGS Ltd
Current assignee: CLARKSTEEL HOLDINGS Ltd
Priority date: 2005-06-21
Filing date: 2005-06-21
Publication date: 2010-01-27
Anticipated expiration: 2025-06-21
Also published as: GB0919435D0; GB0512578D0; GB2427426A; GB2427426B; GB2462031B

Abstract

An access cover lid 10 for use with manholes such as those used for accessing drains, meters, telecommunications nodes. It comprises a first base part 12 dimensioned to cover or substantially cover an opening of the manhole and a second rim part 18 which extends around the base part 12. Fixings are unitarily formed in the base and/or rim to securely engage them together. The fixings may be one or more recesses 32 formed in the rim 18 in which the edge of the base locates so they are held together without the need for further fastening. The recesses 32 can be formed under ribs 24. The lid is preferably tray-shaped to receive an infill. The rim part may only define a side or sides of the tray-shape. Preferably the base part is formed from metal and the rim part from plastics and/or rubber material. A shrink-fit process can be used to secure the rim around the base.

Description

ACCESS COVER LID FOR MANHOLES

This invention relates to an access cover lid for manholes and other utility accesses.

The term utility access' is intended to mean any purpose made opening providing access to a recessed or hidden utility. Such utility accesses are, by way of example, for sewers, drains, meters, telecommunication access points, valves, and stopcocks.

Access cover lids are typically formed from one piece of metal material. This is expensive, both in terms of cost and to the environment. Furthermore, all-metal access cover lids can tend to bind or conode over time to the mating support frame located around the opening being covered. This makes removal of the access cover lid difficult, if not impossible.

The present invention seeks to provide a solution to these problems.

According to the present invention there is provided an access cover lid for a manhole or other utility access as herein defined, the access cover lid comprising a first base part dimensioned to cover or substantially cover an opening of the manhole or other utility access, a second rim part which extends around the first base part, and means unitarily formed as part of the first base part and/or the second rim part for securely engaging the first base part with the second rim part.

A method of forming an access cover lid, in accordance with the invention, comprises the steps of: (a) forming the first part having the base element; (b) moulding the second part; and (c) positioning the first and second parts relative to each other so that, as the second part cools, the second part engages the first part as a shrink fit.

The first part acts as a jig for dimensioning the second part as it cools, advantageously reducing tooling costs.

Preferably, the second part is formed by injection moulding.

Additionally, a further preferable feature is that engagement between the first and second parts is solely by the second part being a shrink fit on the first part. This reduces costs in terms of materials required, and increases production rate.

The present invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of one embodiment of an access cover lid, in accordance with the present invention; and Figure 2 is a section of the access cover lid, taken along line A-A in Figure 1.

Referring to the drawings, there is shown an access cover lid 10 which comprises two parts, a first part 12 being a planar or substantially planar, optionally embossed, rectangular base plate element 14, and a second part 16 being a surrounding rim 18 with a substantially L-shaped lateral cross-section, as can be seen in Figure 2.

The base plate element 14 is formed of any suitable structurally resilient material, such as galvanised steel, stainless steel, brass, aluminium, mild steel, carbon fibre, GRP, glass fibre. Although in this case the base plate element 14 is single ply, it can be a multi-ply plate formed of one or more materials.

The L-shaped rim 18 is, typically injection, moulded from, preferably recycled or recyclable, plastics material, such as polypropylene, PVC or other thermoplastic polymer. However, the rim 18 can be formed from rubber material, a composite material, or any other material which prevents or reduces binding or other undesirable engagement with a cover supporting frame.

As best seen in Figure 2, the interior surface 20 of a back 22 of the rim 18 includes a plurality of spaced buttress-like ribs 24. Each rib 24 is spaced from an interior surface 26 of a base 28 of the rim 18 and tapers from an inwardly projecting position towards a free or upper edge 30 of the back 22 of the rim 18. The spacing of the ribs 24 from the base 28 of the rim 18 provide recesses 32 for engagement of the base plate element 14.

As the rim 18 is extracted from the moulding, it is in a hot expanded state. The base plate element 14 is thus positioned within the expanded rim 18 so that it rests on the base 28 of the rim 18. As the rim 18 cools and contracts, the base plate element 14 enters the recesses 32 formed between the ribs 24 and the base 28 of the rim 18. The base plate element 14 is thus clamped securely by the rim 18.

This method of shrink-fit engagement of the rim 18 with the base plate element 14 dispenses with the need for further discrete fastening means, such as welding, bonding, and screw-threaded fasteners. Tooling is also reduced since the base plate element 14 acts as ajig for dimensioning the rim 18 as it cools.

The arrangement described above provides a tray-shaped access cover lid to receive structural and/or decorative infil, wherein the second rim part solely forms sides of the tray. However, many other shapes of access cover lid can be envisaged, providing the second rim part includes one or more interior recesses allowing the first base part to be held captive therein. For example, the rim could comprise a C-shaped lateral cross-section, thereby enabling a solid-top planar or substantially planar access cover lid to be formed.

The first part itself can include a rim which extends, continuously or non-continuously, around the base plate element. In this case, the recesses of the second rim part are dimensioned to accommodate the rim of the first part.

Instead of a plurality of recesses, the second part can have a single, typically continuous, recess.

Furthermore, access cover lids of other non-circular shapes are possible.

Circular access cover lids can also be produced.

The second rim part can have one or more projections, instead of recesses, adapted to be received in one or more respective recesses formed in an edge of the first base part.

It is thus possible to provide an access cover lid for a manhole or other utility access which is not only structurally extremely resilient to everyday wear and tear, but which can utilise recyclable material. The access cover lid is consequently cheaper to produce, aesthetically more pleasing, and is easier to remove from a supporting frame when in use.

The embodiments described above are given by way of examples only, and modifications will be apparent to persons skilled in the art without departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS1. An access cover lid for a manhole or other utility access as herein defined, the access cover lid comprising a first base part dimensioned to cover or substantially cover an opening of the manhole or other utility access, a second rim part which extends around the first base part, and means unitarily formed as part of the first base part and/or the second rim part for securely engaging the first base part with the second rim part.
2. An access cover lid as claimed in claim 1, wherein the engaging means includes one or more recesses formed in the second rim part in which an edge portion of the first base part is locatable to securely engage the first base part and the second rim part.
3. An access cover lid as claimed in claim 1 or claim 2, wherein the first part is formed of metal material, and the second part is formed of plastics and/or rubber material.
4. An access cover lid as claimed in claim 1, 2 or 3, wherein the base element of the first part is held captive by the second part without independent fastening means.
5. An access cover lid as claimed in any one of the preceding claims, wherein the access cover lid is tray-shaped to receive an infil.
6. An access cover lid as claimed in claim 5, wherein the second part solely defines a side or sides of the said tray-shape.
7. An access cover lid substantially as hereinbefore described with reference to the accompanying drawings.