GB2331539A

GB2331539A - Keyhole plug

Info

Publication number: GB2331539A
Application number: GB9724451A
Authority: GB
Inventors: John Brown; Iain Anthony Campbell
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-11-20
Filing date: 1997-11-20
Publication date: 1999-05-26
Anticipated expiration: 2017-11-20
Also published as: GB2331539A9; GB2331539B; GB9724451D0

Abstract

A resilient plug (20) for plugging a keyhole in a manhole cover (10, fig. 1) to prevent the ingress of dirt and debris, comprises a resilient cap (22) and a shank portion (24). The shank portion is dimensioned to project into the keyhole and be an interface fit therein. The cap portion should be larger than said shank portion and shaped so as not to project above the surface (16, fig. 2) of the manhole cover. The plug is removed by inserting a screwdriver under the cap and levering it out.

Description

2331539 ACCESS COVERS The present invention relates to improvements in or

relating to access covers such as groundhole covers, ground chamber covers, manhole covers, and such like.

An access cover is located as a snug fit within a frame which is fixed to the surface of a pavement or road. Many providers of utility services (such as gas, electricity, water, telecommunications links, and the like) use access covers to gain access to the utilities for maintenance purposes.

These access covers are opened by inserting a lifting tool (key) into one or more apertures (keyholes) in the cover, rotating the key, and then lifting the cover.

However, the keyholes may be blocked by ground dirt, is stones, tar or such like. To allow the key to be inserted, these blockages have to be forcibly removed, often by means of a hammer and chisel.

It is an object of the present invention to obviate or mitigate the above disadvantage.

According to a first aspect of the present invention there is provided a resilient plug for use with an access cover, the plug comprising: a cap portion, and a shank portion projecting from the cap portion, wherein the shank portion is adapted to be removably inserted into a keyhole in the access cover to provide a secure fit therein.

Preferably, the cap portion is dimensioned so that the top of the cap portion does not extend beyond any protrusions on the access cover.

The plug may have lugs on a region of the shank portion so that the shank portion forms an interference fit with the keyhole.

Preferably, the plug is moulded as an integral unit. Alternatively, the portions may be moulded separately and then coupled prior to use.

According to a second aspect of the present invention there is provided a method of maintaining the integrity of a keyhole in an access cover so that a key may be inserted into the keyhole, the method comprising the steps of providing a resilient plug adapted to be removably located in the keyhole and to provide a secure fit therein, and inserting the plug into the keyhole, whereby, in use, the plug covers the keyhole thereby preventing blockage of the keyhole by debris, so that when the plug is removed the keyhole is free of any blockage.

According to a third aspect of the present invention there is provided an access cover system, the system comprising an access cover having one or more keyholes disposed therein, and a resilient plug removably located in at least one of the keyholes, whereby when the access cover is to be opened the resilient plug is first removed from the at least one keyhole to enable a lifting key to be inserted into the keyhole.

These and other aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

Figs la to 1c illustrate three different keyhole shapes in portions of an access cover; Fig 2 is a sectional view showing a keyhole extending all the way through an access cover; Fig 3 is a sectional view showing a keyhole extending only part of the way through an access cover; Fig 4 is a side view of a resilient plug according to one embodiment of the present invention; and Fig 5 is a side view of another embodiment of the present invention.

Figs la to ic show portions of an access cover 10 having a keyhole 14. The access cover of Fig la has surface protrusions 16 (only shown on a portion of the cover 10).

Figs 2 and 3 show sectional side views of an access cover 10 having a keyhole 14 and protrusions 16. In Fig 3 the keyhole 14 only extends part of the way through the cover 10.

Fig 4 shows a plug according to one embodiment of the present invention. The plug 20 comprises an elastomer cap portion 22 and an elastomer shank portion 24 projecting from the cap portion 22. In use, the plug 20 is inserted into the keyhole 14 of an access cover 10 and thereby prevents any debris entering the keyhole 14. When an access cover 10 having a plug 20 fitted therein, is to be removed, the plug 20 is removed by inserting a screwdriver or other flat-bladed implement underneath the cap 22 to lever or prise up the cap 22 to aid cap removal.

The cap 22 is dimensioned so that the width (shown by arrow 26) of the cap 22 extends beyond all parts of the keyhole 14. The cap 22 is oval in shape, having a length of 63.5mm (2.5 inches). In other embodiments the shape of cap 22 may be chosen to match a keyhole shape.

The cap 22 is also dimensioned so that the height of the cap portion (shown by arrow 28) does not extend above any protrusions 16 in the plate. in this embodiment the height of the cap is 2mm. This has the advantage that the cap 22 is not removed by, for example, vehicles or pedestrians passing over the access cover 10.

The shank portion 24 is circular, having a diameter of 25.4mm (1 inch), a length of 35mm (1. 38 inches), and lugs 26 protruding laterally therefrom. These lugs 26 provide an interference fit within the keyhole 14 so that a greater force is required to remove the plug 20, thereby reducing the possibility of accidental plug removal.

Fig 5 shows a modified plug 20a wherein the plug 20a has a shank portion 24 without lugs 26.

It will be appreciated that the plug 20 may be made from any suitable material provided the material has at least a degree of resilience. This may be provided by the shank 24 having a resilient portion.

6

Claims

CLAIMS 1. A resilient plug for use with an access cover, the plug comprising: a cap portion, and a shank portion projecting from the cap portion, wherein the shank portion is adapted to be removably inserted into a keyhole in the access cover to provide a secure fit therein.

1

2. A resilient plug as claimed in claim 1 wherein the shank portion has lugs or ribs on its outer surface.

3. A resilient plug as claimed in either preceding claim, wherein the shank portion is hollow and open at its end remote from the cap portion.

4. A resilient plug as claimed in any preceding claim, wherein the shank portion is generally cylindrical.

5. A resilient plug as claimed in any preceding claim, wherin the cap portion and the shank portion are interconnected by one or more buttress portions.

G. A resilient plug as claimed in any preceding claim and made of a single injection moulded piece from butyl, natural or neoprene rubber or from a urethane plastic material.

7 7. A method of maintaining the integrity of a keyhole in an access cover so that a key may be inserted into the keyhole, the method comprising the steps of providing a resilient plug adapted to be removably located in the keyhole and to provide a secure fit therein, and inserting the plug into the keyhole, whereby, in use, the plug covers the keyhole thereby preventing blockage of the keyhole by debris, so that when the plug is removed the keyhole is free of any blockage.

8. An access cover system, the system comprising an access cover having one or more keyholes disposed therein, and a resilient plug removably located in at least one of the keyholes, whereby when the access cover is to be opened the resilient plug is first removed from the at least one keyhole to enable a lifting key to be inserted into the keyhole.