GB2427426A

GB2427426A - Access cover lid for a manhole

Info

Publication number: GB2427426A
Application number: GB0512578A
Authority: GB
Inventors: Ronald Francis Clark
Original assignee: CLARK DRAIN Ltd; CLARKSTEEL HOLDINGS Ltd
Current assignee: CLARKSTEEL HOLDINGS LIMITED
Priority date: 2005-06-21
Filing date: 2005-06-21
Publication date: 2006-12-27
Anticipated expiration: 2025-06-21
Also published as: GB2427426B; GB2462031A; GB0919435D0; GB0512578D0; GB2462031B

Abstract

The access cover lid 10, for use with manholes such as those used for accessing drains, meters, telecommunications nodes etc., comprises a first part 12 and a second part 16 engageable to the first part, with the first part including a base element formed of a first structurally resilient material that is dimensioned to cover or substantially cover an opening of the manhole, while the second part includes a rim 18 that extends around the periphery of the base of the first part and which is formed of a second material, different to the first material, which prevents or reduces undesirable binding of the lid to the supporting frame. The first part is preferably formed from metal while the second part is preferably formed from plastics and/or rubber material. The base element of the first part is preferably held captive by the second part without independent fastening, with the first part preferably taking the form of a plate and the second part including one or more recesses which engage the plate. The lid is preferably tray-shaped to receive an infill. The second part may only define a side or sides of the tray-shape. Also claimed is a method of forming an access cover lid.

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 corrode 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 a first aspect of 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 part, and a second part engageable with the first part, the first part including a base element dimensioned to cover or substantially cover an opening of the manhole or other utility access and which is formed of a first structurally resilient material, and the second part including a rim which extends around the periphery of the base element of the first part and which is formed of a second material different from the first material and which prevents or reduces undesirable binding of the access cover lid to an access cover support frame. Preferable and/or optional features of the first aspect of the invention are set forth in claims 2 to 6, inclusive. According to a second aspect of the present invention, there is provided a method of forming an access cover lid, in accordance with the first aspect of the invention, the method comprising 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 therefore 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. According to a third aspect of 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. 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 a jig 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 crosssection, 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 noncontinuously, 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

1. An access cover lid for a manhole or other utility access as herein defined, the access cover lid comprising a first part, and a second part engageable with the first part, the first part including a base element dimensioned to cover or substantially cover an opening of the manhole or other utility access and which is formed of a first structurally resilient material, and the second part including a rim which extends around the periphery of the base element of the first part and which is formed of a second material different from the first material and which prevents or reduces undesirable binding of the access cover lid to an access cover support frame.

2. An access cover lid as claimed in claim 1, wherein the first part is formed of metal material, and the second part is formed of plastics and/or rubber material

3. An access cover lid as claimed in claim 1 or claim 2, wherein the base element of the first part is held captive by the second part without independent fastening means.

4. An access cover lid as claimed in any one of the preceding claims, wherein the base element of the first part is in the form of a plate, and the second part includes one or more recesses which engage the plate.

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.

8. A method of forming an access cover lid as claimed in any one of the preceding claims, the method comprising 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

9. A method as claimed in claim 8, wherein the second part is formed by injection moulding.

10. A method as claimed in claim 8 or claim 9, wherein engagement between the first and second parts is solely by the second part being a shrink fit on the first part.

11. 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.

12. An access cover lid as claimed in claim 11, 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