GB2059783A - Cover sheet for sports grounds and the like - Google Patents

Abstract

The sheet comprises: a sheet of waterproof material 2 having one or more inflatable ribs or sleeves 4 each provided with a means 6 whereby the rib or sleeve can be inflated and deflated; and lengths of coiling wire 8 secured along the length of the ribs 4, the elastic forces urging the wires to coil being less than the straightening force applied to the sheet by inflating the ribs, but being sufficiently great to roll the sheet 2 when the ribs 4 are deflated. <IMAGE>

Description

SPECIFICATION Cover sheet The present invention relates to a cover sheet for providing waterproof protection for large areas such as building sites, sections of newly-laid concrete, football pitches or tennis courts.

Cover sheets for these purposes at present in common use comprise flat sheets of waterproof material which are laid over the required area. Generally, the size of the area to be covered requires a few very large sheets, which are difficult and heavy to handle, particularly when wet or snow-covered; our a large number of smaller sheets which have to be aligned and fastened together.

An object of the present invention is the provision of a cover sheet which can be laid and removed quickly and easily.

The present invention provides a cover sheet comprising: a sheet of waterproof material; one or more inflatable ribs connected to the sheet, the or each rib being provided with means whereby the rib can be inflated and deflated, and having secured along at least the length thereof a coiling wire which is pre-set in a coil; the elastic force urging the wire or wires to coil being less than the straightening force applied to the sheet by inflating the or each rib, but said elastic force being sufficiently great to roll the sheet when the or each rib is deflated.

Embodiments of the present invention will be described in detail by way of example. The accompanying drawing shows a top plan view of one embodiment of the invention.

Referring to the drawings, a cover sheet comprises a rectangular sheet 2 of heavy-guage synthetic plastics material, with spaced eyelets 3 along each edge.

At positions approximately 1/3 and 2/3 of the distance across the width of the sheet 2, airtight ribs 4 are secured to the sheet. The ribs 4 are formed separately and then welded or otherwise secured to the sheet Each rib 4 is an elongated airtight pocket with an airtight seal at one end 5 and at the other end a nozzle 6, through which air from a suitable source of compressed air (not shown) can be blown into the rib through a pipe 7, common to both nozzles 6. Each nozzle 6 is fitted with a cut-off for closing the nozzle so that the nozzle can be disconnected from the pipe 7 without exhausting air from the rib.Each nozzle 6 also is provided with a restricting valve whereby the rate of flow of air into and out of the rib 4 can be controlled, to permit gradual inflation and deflation of the rib. A coiling wire 8 is secured along the length of each rib 4 and projects a short distance beyond the rib at the sealed end 5. Each wire 8 is pre-set into a coil, the elastic force of both the wires 8 together being such that when the ribs 4 are deflated, the elastic force is sufficient to re-coil the wires 8 and roll up the sheet 2. However, the elastic force of both the wires 8 tis sufficiently small to be overcome by the straightening force applied to the rolled sheet when the ribs 4 are inflated. Thus, when air is blown into the ribs, they are inflated and straightened against the elastic force of the wires 8, unrolling the sheet 2.

The cover sheet of the present invention is used as follows.

The rolled sheet is laid along one side of the area to be covered, and the pipe 7 is connected to a supply of compressed air. The nozzles 6 are then opened, allowing the compressed air to flow into the ribs 4, inflating them and thereby unrolling the sheet 2 over the area. When the sheet is fully unrolled the nozzles 6 are isolated from the pipe 7 using the cutoff in each nozzle, and the pipe 7 is disconnected from the compressed air supply. This procedure is repeated with further cover sheets if more than one sheet is necessary to cover the whole area. Adjacent sheets can be laced together by threading thongs through the eyelet holes 3 on the edges of adjacent sheets.

To remove the cover sheets from the area, the thongs connecting adjacent sheets are removed, and the restricting valve on each nozzle is adjusted to allow exhaustion of air from the ribs at a suitable rate. For example, if the sheets are covered in snow, a very slow rate of air exhaustion is necessary to allow the snow to be swept from the sheets manually as the sheets roll up. When the ribs are deflated the wires 8 re-coil, rolling the sheet 2 as they do so.

The end of the wire 8 extending beyond the sealed end 5 of each rib helps the wire to start re-coiling against the inertia of the sheet.

The above-described embodiment may be modified to suit particular applications. If the sheet is small or of very light material, one rib may be sufficientto roll and unroll the sheet. A larger or heavier sheet may require more than two ribs to roll and unroll it. Adjacent ribs may be joined at their unsealed ends so that one nozzle serves two or more ribs.

Ribs may be formed integrally with the sheet.

A rope may be secured to the sealed end of the rib, or one of the ribs, and led back to the nozzle end of the rib over the surface of the sheet, so that if the elastic force of the wire or wires proves insufficient to overcome the inertia of the sheet, the rope can be pulled to help start the re-coiling movement of the wire.

Although it is possible to utilise wire of any suitable cross-section such as circular, it is thought desirable to use a flat wire i.e. a wire having a width greater than its thickness. The use of a flat wire tends to assist coiling of the wire to take place along its longitudinal axis.

The ribs can be combined with the sheets in any suitable manner. For example, parallel ribs formed from synthetic plastics material can be superimposed on a sheet of synthetic plastics material at spaced intervals as by welding. Alternatively, a sheet of any required size can be built up using standard ribs which inter-connect adjacent flat sheets of predetermined standard dimensions. As before, any suitable means such as welding can be used to interconnect the intermediate ribs to the adjacent sheet or sheets.

It will be readily appreciated that sheets in accordance with the invention can be used for many applications. For example, if produced from transparent material it can be used for greenhouses or as temporary protective shields during cleaning of buildings or the like. Alternatively, using relatively thin ribs it can be inflated from say the exhaust of a motor vehicle and used to protect and insulate a motor vehicle and possibly occupants in hazardous winter conditions e.g. heavy snow.

Although the ribs and sheets are preferably of synthetic plastics material, it will be appreciated that other suitable materials can be used.

Claims (7)

1. A cover sheet comprising: a sheet of waterproof material; one or more inflatable ribs connected to the sheet, the or each rib being provided with means whereby the rib can be inflated and deflated, and having secured along at least the length thereof a coiling wire which is pre-set in a coil; the elastic force urging the wire or wires to coil being less than the straightening force applied to the sheet by inflating the or each rib, but said elastic force being sufficiently great to roll the sheet when the or each rib is deflated.

2. A cover sheet as claimed in claim 1, wherein the waterproof material comprises synthetic plastics.

3. A cover sheet as claimed in either preceding claim, wherein the inflatable ribs are formed separately from the sheet and welded thereto.

4. A cover sheet as claimed in any preceding claim, wherein said means for inflating and deflating each rib comprises a cut-off valve.

5. A cover sheet as claimed in any preceding claim, wherein a coiling wire is secured to the sheet along the length of each rib.

6. A cover sheet as claimed in any preceding claim, wherein the or each coiling wire is flat in cross-section having a width greater than its thickness.

7. A cover sheet as claimed in claim 1, and substantially as hereinbefore described with reference to the accompanying drawing.