GB2436844A

GB2436844A - Excavation cover

Info

Publication number: GB2436844A
Application number: GB0611476A
Authority: GB
Inventors: Andrew Edwards
Original assignee: Balfour Beatty PLC
Current assignee: Balfour Beatty PLC
Priority date: 2006-06-09
Filing date: 2006-06-09
Publication date: 2007-10-10
Anticipated expiration: 2026-06-09
Also published as: GB0611476D0; GB2436844B

Abstract

The excavation cover, for covering open trenches and the like, comprises a cover plate with upper and lower surfaces, the lower of which has an arrangement of support members, and a number of retaining devices 18 adapted to be releasably supported by the support members so that in use they project downwardly into the excavation beneath the cover. The cover and retaining devices are preferably formed from plastic. The retaining devices preferably comprise a shaft and a perpendicular head with the support members preferably being openings leading to a cavity that are adapted to receive the head of a retaining device such that once inserted the retaining device can be rotated to lock it within the cavity. The arrangement of the support members preferably forms a grid which enables at least two rectangles of different dimensions to be defined by a set of four retaining devices. The cover plate preferably has a ribbed upper surface and chamfered edges.

Description

1

EXCAVATION COVER

2436844

Field of the invention

This invention relates to excavation covers (also known as trench covers), which 5 are devices providing a temporary cover to excavation holes while works are being conducted, for example works to underground utility pipes.

Background of the invention

Many different trench covers are available, and these are generally in the form of a 10 plate which is large enough to cover a particular excavation hole. These covers are essentially designed to meet targets for weight loading. The designs do not, however, provide any securing mechanism for keeping the covers in place.

Summary of the invention

15 According to the invention, there is provided an excavation cover, comprising:

a cover plate having an upper surface and a lower surface, the lower surface having an arrangement of support members;

a plurality of retaining devices adapted to be releasably supported by the support members, the retaining devices in use projecting downwardly from the 20 lower surface into the excavation beneath the cover.

The invention provides a trench cover and simple locking mechanism which provides an adjustable fitting of the cover over a trench, to limit movement and prevent accidental uncovering of the excavation beneath.

25

The cover plate can be formed from plastic, providing the desired durability and also recycling ability.

The support members can each comprise an opening adapted to receive a head 30 of a retaining device. The support members are thus simply defined as part of the overall shape of the cover plate, which can be a single moulded item.

2

Each opening can comprise an entry opening leading to a cavity, and the head of a retaining device is then adapted to be inserted through the entry opening and rotated into a locked position within the cavity.

5 The retaining device may comprise a shaft and a perpendicular elongate head. The head is then inserted through the corresponding shaped opening and rotated into a locked position. The retaining devices can also be plastic.

The arrangement of support members preferably comprises a grid which enables 10 at least two rectangles of different dimensions to be defined by a set of four retaining devices. Thus, a rectangle can be defined by the retaining devices with a size and shape selected to match the excavation opening. The grid may comprise at least ten support members.

15 Brief description of the drawings

An example of the invention will now be described in detail with reference to the accompanying drawings, in which:

Figure 1 shows an example of excavation cover of the invention;

Figure 2 shows the cover of Figure 1 in use; and 20 Figure 3 shows the retaining device in more detail.

Detailed description

The invention provides an excavation cover in which retaining devices project downwardly from a cover plate into the excavation beneath the cover, so that 25 lateral movement of the cover is limited.

As shown in Figure 1, the excavation cover has a cover plate 10 having an upper surface 12 and a lower surface 14. The lower surface 14 has an arrangement of support members 16 in the form of shaped openings. Some of these opening are 30 provided with retaining devices 18 in the form of rotatable keys, and these are releasably engaged in the openings 16.

3

There are more openings 16 than the number of keys which will typically be used with the device, so that the configuration of keys can be selected according to the particular trench.

5 The keys 18 project downwardly from the lower surface 14 so that in use they project into the excavation beneath the cover, and limit lateral movement by butting against the side walls of the trench.

Figure 2 shows the cover in use, covering an excavation which houses a pipe 20, 10 and seated on the earth 22 at the edges of the excavation. The cover plate 10 will typically have dimensions of less than 2m by less than 2m, for example 1.5m x 1m. The cover plate 10 can be formed from polyethylene plastic, for example 35mm thick with a 40 degree chamfer on all edges. The top has a ribbed anti-slip surface.

15

The use of a plastic cover provides increased durability compared to conventional fibreglass trench covers. The device can be used as a temporary footpath, driveway and even low category carriageway.

20 Figure 3 shows in more detail the anti-movement key, which has a shaft 30 and a perpendicular rectangular head 32. The head 32 is inserted through the correspondingly shaped opening 16 and is then rotated between a locked and an unlocked position as shown by the dotted representations and arrows in Figure 3. The keys can also be plastic.

25

The locking mechanism is quick and easy to install, by simply inserting the key and twisting it by 90 degrees out of position. The board is then ready to be placed over an open excavation. This then keeps the trench cover firmly in position. If required the cover can also be secured with masonry nails.

30

The keys create a buffer to prevent the board moving away from the excavation.

4

The arrangement of openings on the underside of the cover plate enables the keys to be fitted to define different sizes and shapes, representing average sizes of excavation. Figure 1 shows ten openings on a substantially circular path. There may be concentric rings of openings or a uniform grid of openings or openings 5 arranged as a star configuration.

The arrangement of openings will be selected to give the required flexibility for the defining opening shapes with a limited set of keys (for example four).

10 The locking device can be considered to be a consumable item, so that keys can be produced on mass though injection moulding and kept in stores on free issue.

The openings have an entry opening corresponding in shape to the shape of the key head, and leading to a cavity in which the head can be rotated. The head can 15 be designed to lock into place, for example at a locking position 34, with the up and down movement of the key restricted.

As mentioned above, the key and cover plate are preferably plastic, but one or other of these components may be in metal.

20

Other locking arrangements are also possible, for example the support members may be recessed threaded shafts and the keys may have threaded bores at the end of a shaft. This again enables each component to be defined as a single moulded item, and enables the keys to be simply screwed into the selected 25 locations.

The dimensions of the cover plate are of course easily scalable, and the particular materials to be used can be freely selected.

30 Various other modifications will be apparent to those skilled in the art.

5

Claims

1. An excavation cover, comprising:

5 a cover plate having an upper surface and a lower surface, the lower surface having an arrangement of support members;

a plurality of retaining devices adapted to be releasably supported by the support members, the retaining devices in use projecting downwardly from the lower surface into the excavation beneath the cover.

10

2. A cover as claimed in claim 1, wherein the cover plate is plastic.

3. A cover as claimed in claim 1 or 2, wherein the support members comprise an opening adapted to receive a head of a retaining device.

15

4. A cover as claimed in claim 3, wherein the opening comprises an entry opening leading to a cavity, and wherein the head of a retaining device is adapted to be inserted through the entry opening and rotated into a locked position within the cavity.

20

5. A device as claimed in any preceding claim, wherein the retaining devices comprise a shaft and a perpendicular elongate head.

6. A device as claimed in any preceding claim, wherein the retaining devices 25 are plastic.

7. A device as claimed in any preceding claim, wherein the arrangement of support members comprises a grid which enables at least two rectangles of different dimensions to be defined by a set of four retaining devices.

30

8. A device as claimed in any preceding claim, wherein the cover plate upper surface is ribbed and the cover plate has chamfered edges.

8. A device as claimed in claim 7, wherein the grid comprises at least ten support members.

6

9. A device as claimed in any preceding claim, wherein the cover plate upper surface is ribbed and the cover plate has chamfered edges.

Amendments to the claims have been filed as follows

1. An excavation cover, comprising:

a plurality of retaining devices adapted to be releasably supported by the support members, the retaining devices in use projecting downwardly from the lower surface into the excavation beneath the cover, wherein the support 10 members comprise an opening adapted to receive a head of a retaining device.

2. A cover as claimed in claim 1, wherein the cover plate is plastic.

3. A cover as claimed in claim 1 or 2, wherein the opening comprises an entry 15 opening leading to a cavity, and wherein the head of a retaining device is adapted to be inserted through the entry opening and rotated into a locked position within the cavity.

4. A device as claimed in any preceding claim, wherein the retaining devices 20 comprise a shaft and a perpendicular elongate head.

5. A device as claimed in any preceding claim, wherein the retaining devices are plastic.

25 6. A device as claimed in any preceding claim, wherein the arrangement of support members comprises a grid which enables at least two rectangles of different dimensions to be defined by a set of four retaining devices.

7. A device as claimed in claim 6, wherein the grid comprises at least ten 30 support members.