GB2321486A

GB2321486A - Temporary covers for trenches and other excavations

Info

Publication number: GB2321486A
Application number: GB9800644A
Authority: GB
Inventors: David Kevan
Original assignee: TARMAC UK Ltd; Tarmac Heavy Building Materials UK Ltd
Current assignee: TARMAC UK Ltd; Tarmac Heavy Building Materials UK Ltd
Priority date: 1997-01-14
Filing date: 1998-01-14
Publication date: 1998-07-29
Also published as: GB9800644D0; GB9700587D0

Abstract

A temporary cover (10,20) for bridging trenches or other excavations comprises a hollow shell of plastics material shaped so as to afford a bridging portion (11) having an upper face (12) which is preferably of generally convex configuration, and locating means comprising a downwardly protruding portion (14) at the underside of the bridging portion (11) to define outwardly presented lateral abutment faces (15) spaced apart by a width corresponding to that of the bench. The hollow shell may be filled with any suitable material, such as foamed plastics material, light-weight foamed concrete, sand or water. Opposite ends of the cover (20) may be formed with means for establishing an articulated connection between adjacent covers along the line of a trench, preferably comprising a part-circular tongue (30) Fig 3 and a part-circular recess (40).

Description

Title: "Temporary covers for trenches and other excavations" Description of Invention This invention relates to temporal+^ covers for trenches or other similar excavations particularly on public highways and associated footpaths or pedestrian areas. The invention has been developed primarily to provide temporally bridging for trenches that ma) be fonned. for example, for the purpose of laying pipes or cables, especially, but not exclusively, in connection with cable television, telephones and other communications systems.

Customarily, such clenches are formed b) means of an excavator with an appropliately dimensioned bucket and, after the pipes or cables have been laid, the trench is filled, eithel with tlle excavated material or foamed concrete or other suitable material, and finished by the application of a layer of macadam or slabs as appropriate.

It is normally desilable to provide temporary bridging over at least selected pans of such trenches, for example to enable pedestrians or vehicles to cross safely. Conventionally, this has been acllieved by the use of steel plates which are simply laid across the trench and retained in position by virtue of their substantial weight. However, the use of steel plates has a number of disadvantages.

In particular their weight makes them difficult to handle and they may easily damage paving slabs or macadamised surfaces onto which they are dropped when being placed in position across a trench.

These considerations apply not only in the bridging of elongated excavations in the fonn of trenches. but also localised holes that mav be foiled to gain access to service pipes or cables in order to effect repair at specific locations.

According to the invention we provide a temporary cover for bridging tienches or other excavations and comprising a hollow shell of plastics material shaped so as to afford a bridging portion with locating means at the underside thereof adapted to enter into a trench or other excavation so as to resist lateral displacement of the bridging portion when in place, the interior of the hollow shell being filled with suitable material.

It will be appreciated that such a temporary cover may be formed in a range of sizes corresponding to specific widtlls of trench tliat are commonly employed, and specifically corresponding to the widths of excavator buckets, or other excavating machines as used in trenching operations. The bridging portion will then have a width which substantially exceeds the width of the trench witli which it is intended to be used, and the locating means will be so dimensioned as to engage the side walls of the trench.

Since such covers are manufactured from plastic, they are much lighter than the steel plates currently used and can in most cases easily be handled by one person.

The, can be manufactured in a range of widths and lengths and can be appropriately reinforced, where necessary, to give the required strength in accordance with anticipated loading conditions. Such reinforcement may take the form of internal or external ribs and!or internal reinforcement in the form of metal rods, grids or the like.

Conveniently, the bridging portion is formed with a generally convex surface at the upper side, and is generally flat at the underside. apart from the provision of the locating means, which may comprise a downwardly protruding portion of the cover at the underside thereof.

Such downwardly protruding portion may define respective laterally presented abutment faces at the opposed edges thereof. spaced apart by a distance corresponding to the width of the trench with which the cover is intended to be used. Alternatively, in some cases, the downwardly protruding portion may comprise t".o ribs each affording a respective laterally presented abutment face spaced apart fiom each other by- the appropn'ate distance.

The material filling the hollow interior may be a foamed plastics material, concrete, particularly light-weight foamed concrete, a particulate solid, such as sand, or a liquid sucli as satel.

According to the invention we also provide a temporary cover for bridging trenches or other excavations and comprising a hollow shell of plastics material shaped so as to afford a bridging portion with locating means at the underside thereof adapted to enter into a trench or other excavation so as to resist lateral displacement of the bridging portion when in place, the shell having a closable filling aperture whereby the interior of the hollow shell may. be filled with suitable liquid or particulate solid.

As mentioned previously, such covers may be made in various lengths and widths, but in accordance with a particularly preferred feature of the invention, the cover is formed with connecting means at opposite ends thereof to enable an articulated connection to be established between longitudinally adjacent covers, thereby enabling the covers to be used to construct a continuous bridging member capable of use on curved sections of trenches as well as on straight sections.

The invention further resides in a tempolary cover for bridging trenches or like excavations and comprising a generally rectangular body shaped so as to afford a bridging portion with locating means at the underside thereof adapted to enter into a trench or other excavation so as to resist lateral displacement of the bridging portion when in place wherein the cover is formed with connecting means at opposite ends thereof to enable an articulated connection to be established bet seen longitudinally adjacent covers, thereby enabling the covers to be used to construct a continuous bridging member capable of use on culled sections of trenches as well as on straight sections.

Niost conveniently, said connecting means comprises a tongue which projects end-wise at one end of the cover and deFines a part-circular bearing face between shoulders formed by' end faces of the cover adjacent thereto, and a corresponding part-circular recess fonned at the other end of the cover and defining a complementary palt-circulat- beanng face between shoulders formed b! end faces of the cover at the other end.

Preferalzln, the part-circular bearing faces afford by the tongue and the recess each subtend an angle of substantially greater than 180 , preferably approximating to 280 -290 , in the case of the tongue and about 250 -260 in the case of tlie recesses, so that the recess Is of undercut forni and ilie tongue is held captive therein against endwise withdrawal, whilst being capable of withdrawal in a direction perpendicular to the bridging portion These and other features of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: FIGURE 1 is a plan view of one embodiment of elongated cover in accordance with the invention; FIGURE 2 is a partially sectioned end iew thereof, FIGURE 3 is a plan view of a second embodiment of elongated cover formed with articulated connecting means in accordance with the invention; FIGURE 4 is a transverse section on the line IV-IRr of Figure 3; FIGURES SA and 5B are respectively- end views in the direction of arrows A and B of Figure 3; and FIGURE 6 is a plan view of three such articulated cover members in assembled relation over a curved section of trench.

The embodiment of cover as shown in Figures 1 and 2 is of simple rectangular form in plan view, and may be of an appropliate length. The cover 10 shown therein is formed as a hollow moulding of any suitable plastics material defining a bridging portion 11 having an upper face 12 of generally convex configuration, in the illustrated embodiment comprising a central flat face 12a and inclined lateral faces 12b. At its underside, the bridging portion 11 includes a pair of laterally spaced supporting faces 13 which are adapted to rest on the surface (S) of the ground on either side of a trench (T) covered thereby. and centrally the cover 10 is formed with a downwardly protruding portion 14 which affords outwardly presented lateral abutment faces 15 spaced apart by a width corresponding to that of the trench (T) with which the cover 10 is intended to be used. so as to engage the side walls of the trench and resist lateral displacement of the cover 10 when in use.

It will be understood that the spacing between the lateral abutment faces 15 need not be such as to afford a close fit between the walls of the trench, and a substantial tolrance Inlay be allowed.

In an alternative arrangement, the lateral abutment faces 15 may be afforded by spaced parallel hollow or- solid downwardly producing ribs formed at the underside of tulle cover 10.

To provide additional rigidity, the hollow interioir 16 of the cover 10 is in the illustrated embodiment filled with a light-weight foamed plastics material 17 which may be introduced thereto through one or more apertures 1S formed in the underside of the portion 14. However, other materials may be used to fill the hollow cover, such as lightweight foamed concrete or particulate material such as sand, or as hereinafter described in relation to the second embodiment a liquid such as water.

The supporting faces 13 may, if desired, be formed with transversely or longitudinally' extending lidges or other suitable glipping folmations to provide resistance to longitudinal or lateral movement of the cover 10 when resting on the surface (S), but it will be appreciated that resistance to lateral movement is predominantly provided by engagement of the lateral abutment faces 15 of the portion 14 with the side walls of the trench (T) adjacent to the surface (S) on which the faces 13 rest.

The inteiior of the hollow cover' 10 maxi, if requited, be divided into longitudinally separate compartments by means of transverse ribs, similar to the end walls 19, in older to provide additional strength. Additionally, or alternatively, metallic or non-metallic reinforcement members man be incorporated in the cover 10.

The second embodiment of cover 20 as illustrated in Figures 3 to 6 is constructed in a generally similar manner to the cover 10, and like reference numerals are used to designate like parts. However, the cover 20 illustrated in Figures 3 to 5 is adapted to be filled with water, and additionally is formed with means providing for an articulated connection between longitudinally adjacent covers.

To enable the interior of the cover 20 to be filled. iii use. with v water, a single filling aperture 2S is fonned at the underside of tlie downwardly protruding portion 14 to receive an externally threaded collar 27 with a tapered bung 29 by means of which the interior cover 20 may be closed subsequent to its being filled with water. It will understood that where the interior of the cover is divided into separate compartments, a respective filling aperture 28 and associated collar 27 and bung 29 will be provided for each compartment Such an arrangement has the advantage that the covers can be filled with water at the site of usage, and drained after use, so as to reduce the weight of the covers during transportation and storage.

Whilst it is prefen-ed to provide a collar 27 within the filling apelture 28, in some cases it may be possible to utilise a bung or stopper that fits directly into the filling aperture. Also, whilst the filling aperture is preferably formed at the underside of the cover, it may in some cases be provided at the upper side.

It will be understood that it would alternatively be possible to fill the cover 20 with a particulate material, such as sand, through the aperture 28 instead of water.

In order to establish an articulated connection, at one end the cover 20 is formed with an end-wise extension in the form of a tongue 30 which maintains the cross-sectional profile of the cover 20. but is of part-ciicular form so as to afford an outwardly directed part-circular bearing face 31, which subtends an angle (p) of substantially in excess of 180 , typically about 285 so as to form a neck 32 at the junction of the tongue 30 with the end face of the cover 20, and the end face is thereby divided into two shoulders 33 which extend away from the tongue at an angle (α) relative to a line transverse to the centreline of the covet 20.

At the other end, the cover 20 is formed with a corresponding partcircular recess 40 which affords an internal part-circular beating face 41 which subtends an angle (y) less than that of the locating face 31, typically about 225 and an open mouth 42 having a width less than the diameter of the recess 40, but greater than the width of the neck 32. Tlie opposite end face of the cover 20 outwardly of the mouth 42 of the recess 40 likewise forms shoulders 43 extending at an angle (α) opposite to the angle (ct) of the shoulders 32.

The arrangement is such iliad a series of covers 20 man be secured together in endwise relation by dropping tile tongue 30 of one cover 20 into the corresponding recess 40 of an adjaceiit cover 20 as shown in Figure 5. The shape and size of the tongue 30 and tlie corresponding recess 40 prevents the adjacent covers 20 being separated in a longitudinal direction and the angled arrangement of the shoulders 32 and 43 enables the adjacent covers 20 to be arranged with the longitudinal centrelines at an angle, so as to allow such covers to follow the line of a curved section of trench.

Whilst the covers as described above are of generally elongated form and intended piinaarily for use in providing temporary bridging over elongated trenches, it will be understood that appropriately shaped and dimensioned covers of similar construction may be used to cover localised square or rectangular holes in a similar manner. For example, it would be possible to cover a rectangular hole using a pair of end cover members and one or more intermediate cover members, each of rectangular form, but smith the end cover members haing inclined lateral faces (similar to be inclined faces 12b of the first embodiment) along one of its longer edges and both of its shoter edges, and with the intermediate cover members having such inclined lateral faces at only their shorter edges, so that in combination such cover members define a flat, rectangular central area with inclined faces around its periphery. At their undersides, the end cover members and intermediate cover members would then be formed with respective downwardly protruding poltions to define outwardly presented lateral abutment faces so located as to be engageable with the sides of the rectangular hole.

Not only does the use of such covers have the advantages of ease and lack of darnage to the surface adjacent to the trench or hole, but additionally, using such covers it may be possible in some cases to eliminate the customar,,' requirement for temporary' banters alongside or around the excavation. Lndeed, the use of such covers may be an economical and preferable alternative to the use of such barriers even where it would not normally be required to bridge the excavation to enable vehicles or pedestrians to cross.

Claims

CLAIMS:- 1. A temporary cover for bridging trenches or other excavations and comprising a hollow shell of plastics material shaped so as to afford a bridging portion with locating means at the underside thereof adapted to enter into a trench or other excavation so as to resist lateral displacement of the bridging portion when in place, the interior of the hollow shell being filled with suitable material.
2. A temporary cover according to Claim 1 wherein the bridging portion is formed with a generally convex surface at the upper side, and is generally flat at the underside, apart fi-om the provision of the locating means.
3. A A temporary cover according to Claim 2 wherein the locating means complise a downwardly protruding portion of the cover at the underside thereof.
4. A temporary cover according to Claim 3 wherein said downwardly protruding portion defines respective laterally presented abutment faces at the opposed edges thereof, spaced apart b! a distance corresponding to the width of the trench with which the cover is intended to be used.
5. A temporary cover according to Claim 3 wherein said downwardly- protruding portion comprises two libs each affording a respective laterally presented abutment face spaced apart from each other by the appropriate distance.
6. A temporary cover according to any one of tlie preceding claims wherein the matenal filling tlie hollow interior is a foamed plastics material.
7. A temporary cover according to any one of Claims I to 6 wherein the material filling the hollow interior is concrete.
8. A temporary cover according to Claim wherein the material is a light weight foamed concrete.
9. A temporary cover according to any one of Claims 1 to 6 wherein the material filling the hollow intrior is a particulate solid.
10. A temporary cover according to Claim 9 wherein said particulate solid is sand.
11. A temporary cover according to any one of Claims 1 to 6 wherein the material filling the hollow interior is a liquid.
12. A temporary cover according to Claim 11 wherein said liquid is water.
13. A temporary cover for bridging trenches or other excavations and comprising a hollow shell of plastics material shaped so as to afford a bridging portion with locating means at the underside thereof adapted to enter into a trench or other excavation so as to resist lateral displacement of the bridging portion when in place, the shell having a closable filling apelture whereby the interior of the hollow shell maybe filled with suitable liquid or particulate solid.
14. A temporary cover according to any one of the preceding claims wherein the cover is formed with connecting means at opposite ends thereof to enable an articulated connection to be established between longitudinally adjacent covers thereby enabling the covers to be used to construct a continuous bridging member capable of use on curved sections of trenches as well as on straight sections.
15. A temporary cos er for bridging trenches or like excavations and comprising a generally rectangular body shaped so as to afford a bridging portion its locating means at the underside thereof adapted to enter mto a trench or other excavation so as to resist lateral displacement of tlie bridging poitioii when in place wherein the cover is formed with connecting means at opposite ends thereof to enable an articulated connection to be established between longitudinally adjacent covers, thereby enabling the covers to be used to construct a continuous bridging member capable of use on curved sections of trenches as well as on straight sections.
16. A temporary cover according to Claim 14 or Claim 15 wherein said connecting means compnses a tongue which projects end-wise at one end of the cover and defines a palt-circular bearing face between shoulders formed by end faces of the cover adjacent thereto, and a corresponding part-circular recess formed at the other end of the cover and defining a complemental part-circular bearing face between shoulders formed by end faces of the cover at the other end.

A temporary cover according to any one of the pleceding claims wherein the cover is formed with connecting means at opposite ends thereof to enable an articulated connection to be established between longitudinally adjacent covers, thereby enabling the covers to be used to construct a continuous bridging member capable of use on curved sections of trenches as well as on straight sections.
17. A temporary cover according to Claim 16 wherein the part-circular bearing faces afforded by the tongue and the recess each subtend an angle of substantially eater than 180 , so that the recess is of undercut form and the tongue is held captive therein against endwise withdrawal, whilst being capable of withdrawal in a direction perpendicular to the bridging portion
1S. A temporary cover according to Claim 17 wherein the palt-circulal- bearing face afforded b) the tongue subtends an angle in tile range 2800 to 290
19. A tenlporaly cover according to Claims 16 wherein the part-circular beang face afibi-ded by the recess subtends an aiigie in the range 2500 to 260
20 A temporary cover substantially as herembefore described with reference to and as shown in Figure 1 and 2 of the accompanying drawings.
21. A temporary cover substantially as hereinbefore described with reference to and as shown n in Figures 3 to 6 of the accompanying drawings.