A ground surface access assembly cover

Abstract

A ground surface access assembly cover 10 with an aperture or keyhole 12 that is threaded 18 and allows for two different means to remove the cover. The ground cover has a hole that is configured to a

Description

Technical Field This invention relates to a cover for a ground surface access assembly (GSAA); and in particular, a cover with an aperture / keyhole providing stable lifting-gear engagement means. Background Art Ground surface access assemblies may be used to gain access to underground chambers housing water supply stop-cocks and water meters, and are frequently located on street pavements. These assemblies often have to withstand heavy loads, imposed by vehicles passing thereover. This means that the covers are typically fabricated from cast (ductile) iron, or the like; which, owing to their weight, should be lifted using approved lifting gear, in order to avoid possible injury to operatives during installation or servicing. In the UK, one or more Lifting Keys (in accord with BS 7903) are generally used to engage keyholes in the cover member. These Lifting Keys engage GSAA keyholes in a similar way to a key engaging a door-lock; that is by alignment of the key-blade with the keyhole, prior to insertion and then by part rotation of the key-shaft. Such Lifting Keys (see Figure 8) are generally configured to allow ergonomic hand engagement by an operative, and thus are not well suited for rigid / safe connection to motorised lifting gear. Summary of Invention An aim of the present invention is to provide a GSAA cover with an aperture adapted, in use, to engage two different lifting-means. A further aim is to provide means of rigidly connecting said cover to one of these said lifting-means so as to allow safe mechanical lifting of heavy GSAA covers. The present invention provides a ground surface access assembly cover with a novel aperture: that can be either engaged for lifting using a standard (for example; in accord with BS 7903) lifting key, or alternatively by additional engagement means; using rigid connection thereby, allowing safer, non-manual, lifting of the cover; typically using mechanical lifting equipment. In one aspect, the invention comprises: a ground surface access assembly cover (10) having an aperture (12) configured to allow insertion of a standard lifting key (K) characterized in that said aperture (12) further comprises an internally threaded portion (18) configured to also / alternatively allow rigid connection of a lifting tool (L) having an externally threaded shaft. In another aspect the invention is a ground surface access assembly cover (10) comprising an aperture (12) configured to allow insertion and subsequent engagement using a standard UK lifting key (K): characterized in that said cover aperture (12) further comprises an internally threaded portion (18) configured to also / alternatively allow rigid screwed-connection of an externally threaded lifting tool (L). In another aspect, the invention comprises a system / method of rigidly engaging a ground surface access assembly cover (10) comprising an aperture (12) configured to allow insertion of a standard hand-held lifting key (K): characterized in that said aperture (12) further comprises an internally threaded portion (18) dimensioned to allow tight connection to a lifting tool (L) comprising a male-threaded shaft dimensioned to engage said threaded portion (18); comprising the following steps: (a) Screwing said male-threaded shaft of said lifting tool (L) within said internally threaded portion (18) of said cover aperture (12); (b) Connecting said lifting tool (L) to mechanised lifting equipment. In all of the above aspects: Preferably, said aperture (12) comprises a circular hole (14) with at least one adjoining rectangular hole (20,22). Thus, in plan view, the aperture (12) comprises at least one rectangular portion (20) adjoining a segmented circular portion (14). More preferably, in plan view, the aperture (12) comprises two rectangular portions (20,22) with an intermediate “circular” portion (14) comprising two minor segments. Preferably, said internally threaded portion (18) is formed within said circular hole (14). Preferably, said internally threaded portion (18) is formed within a central portion of said aperture (12). Preferably, said lifting tool (L) comprises a threaded lifting loop. Brief Description of Drawings The present invention is illustrated by the following diagrammatic figures in which: Figure 1 shows a (cut-away) perspective view of a GSAA aperture / keyhole according to the present invention; Figure 2 shows a perspective view of the aperture / keyhole illustrated in Figure 1 located centrally in a rectangular GSAA cover member; Figure 3 shows a plan view / elevation of the aperture / keyhole illustrated in Figure 1; Figure 4 shows a sectioned view (along the lines X-X) of the aperture / keyhole illustrated in Figure 3; Figure 5 shows a sectioned view (along the lines Y-Y) of the aperture / keyhole illustrated in Figure 3; Figure 6 shows a sectioned of stable keyhole engagement means (L) connected to the keyhole illustrated in Figure 4; Figure 7 shows an example of stable keyhole engagement means (L) in accord with the present invention; and Figure 8 illustrates a Lifting Key in accord with BS 7903. Detailed Description Figure 2 illustrates a perspective view of preferred embodiment of a GSAA cover aperture / keyhole, located centrally in a rectangular cover; according to a preferred embodiment of the present invention. The ground surface access assembly cover (10) comprises an aperture (12) configured to allow insertion of a lifting key / tool (K): characterised in that said aperture (12) comprises an internally threaded portion (18), configured to alternatively allow rigid connection of an externally threaded lifting tool (L). Many GSAA covers in the UK have at least one keyhole configured to allow partial insertion of a standard UK Lifting Key (as illustrated in Figure 8). Following insertion of the Key Blades (Kb), the key handle (Kh) is used by an operative to partially rotate the Key Shaft (Ks) thereby allowing non-rigid engagement of said cover, thus enabling manual lifting of many covers. However, some covers are too heavy to be lifted manually; typically, roadway covers that have to withstand high loads imposed by heavy commercial vehicles. Also, some medium-weight covers can be unsafe to lift manually, owing to sealing to the supporting frame, due to physical deterioration of the cover and said surrounding support frame. In such circumstances, the ability to engage said aperture (12) with both a standard lifting key (K) or alternatively with a rigidly connectable lifting tool (L) that forms part of a mechanical lifting system is advantageous; compared with known alternatives. Figure 1 shows an enlarged cut-away perspective view of engagement aperture housing (16) and the engagement aperture (12), illustrated in Figure 2; and part of the rest of the cover (10). In particular, Figure 1 shows that the engagement aperture (12) comprises an internally- threaded portion (18) configured to allow rigid connection of a lifting tool comprising a male-threaded shaft (not illustrated). The engagement aperture housing (16) may, optionally, be manufactured separately from the remaining part of the cover; that is typically of cast-iron; and subsequently permanently connected to the surrounding (main) cast-iron portion. Figure 3 shows a plan view corresponding to Figure 1 and Figures 4 and 5 show sectioned views along the lines X-X and Y-Y (shown in Figure 3) respectively. When the cover (10) is rectangular (as illustrated), the GSAA aperture (12) typically comprises a centrally positioned (generally circular segment portions 14) that are threaded and two adjoining generally rectangular portions (20,22). Figure 4 shows sidewalls 20a, 22a of the two adjoining generally rectangular portions (20,22) respectively and also a keyway pocket (24), located beneath the aperture / keyhole (12); the purpose of which is to prevent unwanted material passing through the GSAA to any cavity underneath. Thus, material can only enter / exit said keyway pocket (24) via aperture / keyhole 12. Optionally, there may be just one (single) rectangular portion (20) - not illustrated in Figure 3. The GSAA aperture (12) illustrated in Figure 3 is commonly described as a lifting-key “Keyhole” and would be suitable for engagement of a standard UK Lifting-Key, in accord with BS 7903 (as illustrated in Figure 8). However, a less preferable lifting key with a single blade (Kb) would normally engage a GSAA aperture (12) with just a single rectangular portion (20). The lifting tool (L) having an externally threaded shaft may take several forms; however, it is important that the GSAA aperture has a matching internally threaded portion (18), that, firstly by partial insertion; and then by turning within said GSAA aperture (12), can firmly engage said externally threaded shaft; in a similar way to how a nut engages a bolt. Figure 6 shows show a cross-sectional view of lifting tool that (L) that has rigidly engaged said GSAA aperture (12), illustrated in Figure 5; following insertion and turning within said aperture (12). This (preferred) Lifting Tool (30) comprises a loop (32) that can readily be connected to a mechanical lifting device; supported by a base portion (34) that has an adjoining shaft (36) the greater part of which has a threaded portion (38) dimensioned to match the internally threaded portion (18) of said GSAA aperture (12). Figure 7 shows a side view of the preferred Lifting Tool (30) illustrated in Figure 6. Figure 8 illustrates a Lifting Key in accord with BS 7903. The cover (10) may comprise two separate triangular parts, in such circumstances an aperture (12) is preferably located at the centre of gravity of each triangular part / portion. Whatever the shape of the cover (10) any single aperture (12) is preferably located at, or near to, its centre-of gravity. Large GSAA covers may have two or more apertures (12).

Claims

1. A ground surface access assembly cover (10) with an aperture (12) comprising a circular / elliptical hole (14) and at least one additional adjoining rectangular hole (20,22) configured to allow insertion of a standard lifting key (K) characterised in that said aperture (12) further comprises internally threaded portion(s) (18) configured to allow rigid connection of a lifting tool (L) having an externally threaded shaft.

2. A ground surface access assembly cover (10) according to Claim 1 comprising two additional adjoining rectangular holes (20,22).

3. A cover (10) according to Claim 1 or 2 wherein said internally threaded portion (18) is formed within said circular / elliptical hole (14).

4. A cover (10) according to any of Claims 1 to 3 wherein said internally threaded portion (18) is formed within the central portion of said aperture (12)5. A method of rigidly engaging a ground surface access assembly cover (10) with an aperture (12) comprising a circular / elliptical hole (14) and at least one additional adjoining rectangular hole (20,22) configured to allow insertion of a lifting key (K): characterized in that said aperture (12) further comprises an internally threaded portion (18) dimensioned to allow tight connection to a lifting tool (L) comprising a male-threaded shaft dimensioned to engage said cover aperture (12); comprising the following steps:(a) Threading said male shaft of said lifting tool (L) within said internally threaded portion (18) of said cover aperture (12);(b) Connecting said lifting tool (L) to mechanised lifting equipment.

6. A method / system according to any preceding claim wherein said lifting tool (L) comprises a threaded lifting loop.

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