GB2373278A

GB2373278A - Temporary cover plate for a manhole

Info

Publication number: GB2373278A
Application number: GB0203978A
Authority: GB
Inventors: Roger Nicholas Hicks
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-02-20
Filing date: 2002-02-20
Publication date: 2002-09-18
Anticipated expiration: 2022-02-20
Also published as: GB2373278B; GB0203978D0; GB0104106D0

Abstract

The temporary cover plate, particularly for covering manholes during construction work, comprises a plate 1 provided with at least two locating lug means 2,3 that extend downwardly, in use, therefrom and which are so spaced from one another as to be contactible with opposed edges of the manhole to prevent sideways movement of the plate. The cover plate preferably has each of the at least two locating lug means extending substantially parallel to a respective side of the plate and spaced from the respective side so as to define a support zone of the plate adapted to rest on the edge of the manhole. The locating lug means may comprise a section of angle that has one face fixed to the plate and the other face forming the locating lug means. The cover plate may have four angles fixed to the underside, with a first pair of angles parallel to one another and the second pair of angles disposed perpendicular to one another. One or more reinforcing ribs may be located in a zone between the locating lug means.

Description

MANHOLE COVER PLATE This invention relates to a device which is used to cover the opening of a drainage manhole during construction work.

During the course of a construction project, drain pipes are laid in the ground and manholes are constructed, but the permanent manhole covers cannot be fitted to the manhole structure itself, as the precise level at which the manhole cover should be set, to align with the level of and any gradient of the finished tarmacadam or other surface, is not known until much later during the project.

The opening within the top of the manhole presents a hazard to persons on the construction site, where they may fall into the manhole. The opening is, by design, large enough to allow a person to enter the manhole itself, to carry out maintenance work. In the UK the common size of this opening is 600mm x 600mm. The depth of the shaft will vary, but may often be sufficient for a fall to cause serious injury or even death. The opening may also present a hazard to vehicles crossing the'onstruction site, where their wheel (s) may become stuck in the opening.

Construction materials or general detritus may fall into the opening, causing a blockage in the newly laid drain.

Often, the permanent manhole cover may be placed loosely over the opening. This may afford protection to foot traffic, preventing persons from falling into the manhole. However, should a vehicle pass by the manhole or travel over the manhole, the manhole cover may be dislodged, as it has no method of being restrained against horizontal movement.

A sheet of wood may be placed to protect the opening, but, should a vehicle drive over the sheet of wood, the load transmitted by the vehicle's wheel may pierce the sheet of wood, rendering the manhole opening unprotected.

A large sheet of steel may be placed to protect the opening, the sheet being of sufficient size over and above the size of the manhole opening to allow for the sheet being dislodged horizontally without the opening in the manhole becoming uncovered. However this would mean that the sheet of steel would have a considerable size and therefore weight, and it would require mechanical means to place and remove the sheet.

It is an object of this invention to provide a cover plate of suitable strength to allow the passage of a goods vehicle over it, with downward facing lugs attached to the plate, which would prevent the plate from moving horizontally when struck by a vehicle, but where the combination of plate and lugs can easily and safely be lifted and sited by hand. According to the present invention, there is provided a temporary cover plate for a manhole comprising a plate provided with at least two locating lug means extending downwardly, in use, therefrom and so spaced one from another as to be contactible with opposed edges of the manhole to prevent sideways movement of the plate.

Preferably, each of the at least two locating lug means extends substantially parallel to a respective side of the plate and is so spaced from said side as to define a support zone of the plate adapted to rest on the edge of the manhole.

Advantageously the or each locating lug means comprises a section of angle having one face affixed to the plate and the other face forming the locating lug means.

The plate may be provided with four angles fixed to its underside, in which case the four angles are disposed with a first pair of angles parallel one to the other, and the second pair of angles are disposed perpendicular to the first pair.

The plate may further comprise one or more reinforcing ribs located in a zone between the locating lug means.

A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 shows a plan view of the cover; Figure 2 shows a view of the underside of the cover; Figure 3 shows a perspective view of the underside of the cover; Figure 4 is an elevation from one side ; and Figure 5 is an elevation from a second side.

As stated above, a manhole is approximately 600mm square (2 foot x 2 foot). Immediately below the manhole cover is a chamber, perhaps 800mm square and at least 200mm deep which accommodates a seat for the manhole cover. Below this is a shaft down to the drain.

On a building site, the final ground level or its gradient profile cannot be determined until near the end of the project. Until then the upper chamber cannot be completed, although it will form a base for a temporary cover plate.

As shown in Figure 3, the manhole cover plate comprises a plate I having two pairs of locating angles 2,3 fixed to its underside, with one face of each angle 2,3 fixed to the plate 1, so the other face of the each angle 2,3 extends downwards, at 90 degrees from the plate 1.

When the plate 1 together with the angles 2,3 are sited on the opening in a drainage manhole which is under construction, the downward projecting faces of the angles 2,3 locate easily within the opening in the drainage manhole, and the plate is supported by the portions outwardly of the angles 2,3.

When a person or vehicle travels across the drainage manhole the plate 1 supports the load of the person or vehicle, preventing the person or vehicle from falling into the opening in the drainage manhole. Should any force be transmitted horizontally by the person or vehicle so as to cause the plate 1 to attempt to move horizontally, the downward projecting faces of the angles 2, 3 will hit the sides of the opening in the drainage manhole, and prevent the plate 1 from moving horizontally.

The angles 2,3 may be shortened to form effectively individual locating lugs, with one, two or more on each side.

Should any construction materials or detritus be spilled around the drainage manhole, the location of the plate 1, being positioned across the opening in the drainage manhole, will prevent such materials or detritus from falling into the drainage manhole.

The manhole cover plate would be removed from the opening in the drainage manhole prior to the final fixing of any permanent manhole cover.

The manhole cover plate can then be reused to cover the opening in another drainage manhole.

The manhole cover plate could be reused as described above on many other future projects.

The manhole cover plate would be so constructed as to be sufficiently strong to carry imposed loads from persons, vehicles or materials, yet to be light enough to be placed by hand, rather than requiring mechanical means of lifting, transporting and placing. Ideally, the plate 1 comprises steel of thickness between 2mm and 10mm, optionally between 3mm and 6mm. The angles 2,3 contribute to the stiffness of the plate. In order to reduce the plate thickness, one or more reinforcing ribs (not shown) may be attached across the central zone of the plate, for example in a diagonal orientation.

Claims

CLAIMS 1. A temporary cover plate for a manhole comprising a plate provided with at least two locating lug means extending downwardly, in use, therefrom and so spaced one from another as to be contactible with opposed edges of the manhole to prevent sideways movement of the plate.
2. A plate as claimed in claim 1, wherein each of the at least two locating lug means extends substantially parallel to a respective side of the plate and is so spaced from said side as to define a support zone of the plate adapted to rest on the edge of the manhole.
3. A plate as claimed in either claim 1 or claim 2, wherein the or each locating lug means comprises a section of angle having one face affixed to the plate and the other face forming the locating lug means.
4. A plate as claimed in claim 3, provided with four angles fixed to its underside.
5. A plate as claimed in claim 4, wherein the four angles are disposed with a first pair of angles parallel one to the other, and the second pair of angles are disposed perpendicular to the first pair.
6. A plate as claimed in any one of the preceding claims, further comprising one or more reinforcing ribs located in a zone between the locating lug means.
7. A manhole cover plate substantially as herein described with reference to the Figures of the accompanying drawings.