GB1562638A - Tarpaulins - Google Patents

Description

(54) IMPROVEMENTS IN AND RELATING TO TARPAULINS (71) We, CLARO PLASTICS LIMITED, of Thorpe Arch Trading Estate, Boston Spa, Wetherby, West Yorkshire, (formerly of Carrbridge in the County of Inverness, Scotland), a British Company, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: The invention relates to tarpaulins.

In its broadest aspect, the invention provides a tarpaulin comprising a sheet of flexible thermoplastics material and an elongate flap which extends along at least one edge region of the sheet and which is secured to the sheet along a line spaced inwardly of that edge of the sheet, the flap and the said edge region of the sheet each carrying respective co-operating halves of one of a series of cleat-and-eyelet fasteners which enable the flap to be releasably fastened to the sheet at spaced points along said edge region and which also allow a correspondingly-eyeleted edge of a further tarpaulin to be sandwiched and fastened between the flap and the said edge region of the sheet.

Preferably a flap having the features outlined above extends along each of two adjacent edges of the tarpaulin. For example, where the tarpaulin is rectangular, a flap may extend along each of two mutually perpendicular edges of the tarpaulin. The remaining two edges can then be eyeleted, or one eyeleted and one cleated, without flaps so that a plurality of tarpaulins each embodying this construction can be joined to one another along their edges, by sandwiching and fastening the non-flapped edges of one tarpaulin between the flapped edges of the next.

The invention is particularly applicable to tarpaulins for use in sheeting a scaffolded structure, and accordingly the tarpaulin may be reinforced with strips of webbing (i.e.

elongate bands of material having high width-to-thickness ratio) which extend around the periphery of the sheet and are bonded to the sheet. These reinforcing strips may extend along and across the tarpaulin in an open mesh along lines which, in use of the tarpaulin, will coincide with the runs of the scaffold standards (vertical poles) and ledgers (horizontal poles); the strips in such a construction being bonded to one another as well as to the sheet.

The reinforcing strips may for example comprise thermoplastics, metallic or inorganic yarns enclosed in a thermoplastics casing.

Such yarns may also extend along and across the tarpaulin as a whole, and in this case the necessary reinforcement may be achieved without increasing the overall amount of yarn used, by lessening the yarn and/or polymer density in areas of the tarpaulin between the reinforcing strips and by increasing the yarn and/or polymer density in the reinforcing strips themselves.

The reinforcing strips at the edges of the tarpaulin, which conveniently may accommodate the cleat-and-eyelet fasteners, may be so constituted as to have a minimum of 40% extension under load before they break. In a further development of this aspect of the invention, all the reinforcing strips may be so constituted.

Thus, a tarpaulin embodying the construction just outlined has all the advantages of light weight, translucence, high strength and prevention of tear spreading which the reinforced construction gives; has the additional advantage, when applied to the sheeting of a scaffolded structure, that tearing of the tarpaulin by the scaffold standards, ledgers and fittings is specifically allowed for and resisted by the tarpaulin construction; and allows a windproof and virtually waterproof connection of one tarpaulin to another to be made.

In addition, if strips having a minimum 40% extension under load before breaking are used, a scaffolded structure sheeted with tarpaulins embodying the invention can withstand some shock loading (for example, gusts of wind) since this is again specifically allowed for in the tarpaulin construction.

With known canvas-based tarpaulins, sudden or repeated shock gusts can loosen the tarpaulin from its points of attachment to the scaffold or - in frequent cases - can rip the tarpaulin since it has virtully no inherent resilience.

In a presently-preferred construction, cleats and eyelets of a plastics material are heat-welded in a spaced series along the back faces of the sheet and the flap, and preferably specifically along the reinforcing strips running up one or more edges of the tarpaulin. With such a construction, the shear forces along the cleat/sheet or eyelet/ sheet interface are minimised. Even if the cleat or the eyelet is pulled from the sheet or flap by such forces, the sheet or flap will still be held between the cleat and the securing rope, and the tarpaulin will stay in place.

In any of these arrangements in which the strips also run across the tarpaulin, they may run diagonally along the lines which, in use of the tarpaulin, will coincide with the diagonal braces of the scaffold structure.

British Patent Specification No. 1,454,314 discloses specific methods of making tarpaulins comprising a sheet of flexible thermoplastics material integrally reinforced with strips of webbing which extend in an open mesh over substantially the whole of the sheet and are bonded to the sheet and to one another. The reader is directed to the disclosure of Specification 1.454.314 should he need detailed instructions, over and above those which now follow, to put the present invention into practice.

The accompanying drawings show by way of example only, one tarpaulin embodying the present invention. In these drawings: Figure 1 shows in perspective a corner region of the tarpaulin; Figure 2 shows, to an enlarged scale and in side elevation, an edge region of the tarpaulin of Figure 1; and Figure 3 shows, to an even more enlarged scale, one of the reinforcing strips and the pattern of yarn filaments running through it.

Referring now to these drawings in detail, the tarpaulin basically comprises a rectangular sheet of flexible thermoplastics material such as polyvinylchloride or polyethylene.

The sheet is reinforced across substantially the whole of its area with strips of webbing (i.e. elongate bands of material having a high width-to-thickness ratio). The webbing strips extend in an open mesh over the sheet, and are bonded to the sheet and to one another.

In this particular tarpaulin, the sheet and the webbing strips are both initially transparent, and are reinforced with bundles of inorganic yarn filaments which are heatfused to the thermoplastics material by, for example, any of the methods disclosed in our British Patent Specification No.

1,454,314. The yarn filaments may comprise a straight foward rectangular scrim pattern throughout the sheet and the webbing strips, or alternatively they may be arranged as in Figure 3 in which they follow sinusoidal patterns in the sheet. In the particular example of Figure 3, the scrim pattern adopted gives the sheet a greater extension lengthways than width-ways, and this property can be useful in certain applications to which the tarpaulin is put.

Elongate flaps extend along two adjacent and mutually perpendicular edge regions of the tarpaulin, as Figure 1 shows. These flaps are each made of the same yarn-reinforced thermoplastics sheeting as the remainder of the tarpaulin. They are each secured to the tarpaulin along a respective continuous line of heat-bonding. The heat-bonding lines are spaced inwardly of the tarpaulin from the respective edge of the sheet and, as Figure 1 shows, run parallel to the sheet edges. The free edge of each flap overlies the adjacent edge of the sheet and so also overlies the webbing strip running along that edge. Each flap is of only a single thickness of material, except along the lines of heat-bonding where the sheet combines with the flap material to form a double-thickness layer.

As Figure 2 shows in detail, a plastics eyelet is heat-welded to the back face (i.e.

the face which overlies and contacts the tarpaulin edge region of the flap. As Figure 2 shows also, a co-operating cleat of similar plastics material is heat-welded to the back face of the tarpaulin. The flap and the sheet have, of course, first been perforated to accommodate respectively the eyelet and the cleat. A series of co-operating pairs of such cleats and eyelets is welded along the length of each of the two flapped edges of the tarpaulin, as shown in Figure 1.

The other two edges of the tarpaulin, not shown in the drawings, are reinforced with the webbing strips but are not provided with flaps. Instead, a line of eyelets each similar to the eyelet shown in Figure 2 is secured along each of these edges.

In use, the eyeleted and un-flapped edge of an adjacent tarpaulin (not shown in the drawings) can be sandwiched and fastened between the flap and the underlying edge of the tarpaulin of Figure 1, so that when securing ropes are passed through the fastened cleats a windproof and virtually waterproof joint between the two tarpaulins is obtained. A series of tarpaulins of this two-edge-flap construction can then be used to sheet completely a scaffolded structure.

The tarpaulins described above find a number of practical uses. For example, when sheeting the load on an open-topped vehicle the reinforcing strips of webbing can be disposed in areas subject to high flexing forces - such as the top of the load, when they would extend across the central regions of the sheet. Thus, a vehicle sheet can be produced offering extremely high flexing resistance at low cost and light weight. As has already been mentioned, the density of the sheeting and reinforcing yarn could be distributed appropriately to withstand the flexing forces in such a sheet.

It is emphasised that it may not always be necessary to secure an initially separate eyelet component into the flap. The eyelet could simply be formed in the flap, rather than being constituted by a separatelywelded component.

WHAT WE CLAIM IS: 1. A tarpaulin comprising a sheet of flexible thermoplastics material and an elongate flap which extends along at least one edge region of the sheet and which is secured to the sheet along a line spaced inwardly of that edge of the sheet, the flap and the said edge region of the sheet each carrying respective co-operating halves of one of a series of cleat-and-eyelet fasteners which enable the flap to be releasably fastened to the sheet at spaced points along said edge region and which also allow a correspondinly-eyleted edge of a further tarpaulin to be sandwiched and fastened between the flap and the said edge region of the sheet.

2. A tarpaulin according to claim 1, in which the sheet of thermoplastics material is reinforced with strips of webbing (i.e. elongate bands of material having a high widthto-thickness ratio) which extend around the peripheral region of the sheet and are bonded to the sheet, and in which the cleats (or the eyelets) carried by the tarpaulin edge region are secured to the tarpaulin along one of said reinforcing strips.

3. A tarpaulin according to either preceding claim, in which the cleats (or eyelets) are bonded to the back face of the thermoplastics material of the flap (or the edge region).

4. A tarpaulin according to either of claims 2 and 3, in which the or each edge-reinforcing strip can accommodate a minimum of 40% extension under load before breaking.

5. A tarpaulin according to claim 4, in which reinforcing strips extend in an open mesh over substantially the whole of the sheet and can each incorporate a minimum of 40% extension under load before they break.

6. A tarpaulin according to claim 5, in which the reinforcing strips extend in a rectangular mesh whose lines can, in use, conicide approximately with scaffold standards and ledgers forming a scaffolded structure to be covered by a number of the tarpaulins.

7. A tarpaulin according to claim 6, including reinforcing strips extending diagonally across the rectangular mesh.

8. A tarpaulin according to any of the preceding claims, in which flaps are provided along two adjacent edges of the tarpaulin.

9. A tarpaulin substantially as described herein with reference to, and as illustrated in, Figures 1 and 2 of the accompanying drawings.

10. A tarpaulin according to claim 9 when modified as in Figure 3 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. two-edge-flap construction can then be used to sheet completely a scaffolded structure. The tarpaulins described above find a number of practical uses. For example, when sheeting the load on an open-topped vehicle the reinforcing strips of webbing can be disposed in areas subject to high flexing forces - such as the top of the load, when they would extend across the central regions of the sheet. Thus, a vehicle sheet can be produced offering extremely high flexing resistance at low cost and light weight. As has already been mentioned, the density of the sheeting and reinforcing yarn could be distributed appropriately to withstand the flexing forces in such a sheet. It is emphasised that it may not always be necessary to secure an initially separate eyelet component into the flap. The eyelet could simply be formed in the flap, rather than being constituted by a separatelywelded component. WHAT WE CLAIM IS:

1. A tarpaulin comprising a sheet of flexible thermoplastics material and an elongate flap which extends along at least one edge region of the sheet and which is secured to the sheet along a line spaced inwardly of that edge of the sheet, the flap and the said edge region of the sheet each carrying respective co-operating halves of one of a series of cleat-and-eyelet fasteners which enable the flap to be releasably fastened to the sheet at spaced points along said edge region and which also allow a correspondinly-eyleted edge of a further tarpaulin to be sandwiched and fastened between the flap and the said edge region of the sheet.

2. A tarpaulin according to claim 1, in which the sheet of thermoplastics material is reinforced with strips of webbing (i.e. elongate bands of material having a high widthto-thickness ratio) which extend around the peripheral region of the sheet and are bonded to the sheet, and in which the cleats (or the eyelets) carried by the tarpaulin edge region are secured to the tarpaulin along one of said reinforcing strips.

3. A tarpaulin according to either preceding claim, in which the cleats (or eyelets) are bonded to the back face of the thermoplastics material of the flap (or the edge region).

4. A tarpaulin according to either of claims 2 and 3, in which the or each edge-reinforcing strip can accommodate a minimum of 40% extension under load before breaking.

5. A tarpaulin according to claim 4, in which reinforcing strips extend in an open mesh over substantially the whole of the sheet and can each incorporate a minimum of 40% extension under load before they break.

6. A tarpaulin according to claim 5, in which the reinforcing strips extend in a rectangular mesh whose lines can, in use, conicide approximately with scaffold standards and ledgers forming a scaffolded structure to be covered by a number of the tarpaulins.

7. A tarpaulin according to claim 6, including reinforcing strips extending diagonally across the rectangular mesh.

8. A tarpaulin according to any of the preceding claims, in which flaps are provided along two adjacent edges of the tarpaulin.

9. A tarpaulin substantially as described herein with reference to, and as illustrated in, Figures 1 and 2 of the accompanying drawings.

10. A tarpaulin according to claim 9 when modified as in Figure 3 of the accompanying drawings.