A TARPAULIN

Abstract: The invention relates to a tarpaulin (1) comprising a woven basic fabric (2) made water-proof, and several fastening means (5, 6) for fastening the tarpaulin (1) to a transport means. A problem with previous tarpaulins has been that they are not alone able to bind the load but chains, for instance, have to be used. This problem is avoided by means of a tarpaulin according to the invention, which is characterized in that the warp yarns of the basic fabric (2) are multifilament yarns, and that areas (3) woven mainly with flat-film yarns as weft yarns and reinforced areas (4) woven with multifilament weft yarns having a greater thickness and tensile strength than warp yarns alternate in the basic fabric in the warp direction, the fastening means (5, 6) being attached to the reinforced areas (4) of the basic fabric (2).

Description: A tarpaulin The invention relates to a tarpaulin comprising a woven basic fabric made water-proof, and several fastening means for fastening the tarpaulin to a transport means. Tarpaulins of this type are used widely during transport to protect the load against rain and snow or other disadvantageous environmental or weather ef- fects. Tarpaulins are usually made of woven and/or laminated polyethene or polypropylene. They usually comprise cords or the like means for binding the tar¬ paulin to the transport means and for tightening it over the load. Prior art tarpaulins, however, are not alone able to keep the load in position during trans¬ port, because they are easily torn under the influence of the weight of the load when a ship sways or when a lorry brakes suddenly, for instance. According to re¬ gulations, a load should be fastened so as to with- stand forces of 1 G in every direction in transport by sea and forces of 1 G in the forward direction and forces of 0.5 G in the backward or any other direction in transport by land. In order to comply with the re¬ gulations, the load has to be fastened separately by means of various irons and chains, which requires sev¬ eral workmen at the different transport stages and is many cases also machines for displacing heavy irons and chains. Similarly, the load fastening means are difficult to detach at the receiving end. The fas- tening means are not usually returned by the receiver, which increases the cost of transport. In addition, the fastening chains may damage the load, e.g., tear down paper rolls. The object of the present invention is to elim- inate the above problems and disadvantages. This is achieved by means of a tarpaulin of the type described in the preamble, which according to the invention is characterized in that the warp yarns of the basic fabric are multifilament yarns, and that areas woven mainly with flat-film yarns as weft yarns and reinforced areas woven with multifilament weft yarns having a greater thickness and tensile strength than the warp yarns alternate in the basic fabric in the warp direction, the fastening means being attached to the reinforced areas of the basic fabric. The tarpaulin according to the invention is sufficiently durable to be used both for the packing and protection of the load as well as for the fasten¬ ing of the load so as to comply with the above-men- tioned regulations. No other fastening means are needed. Since the fastening means are attached to the reinforced areas of the tarpaulin, the strains caused by the load are mainly exerted on these reinforced areas. For this reason, the areas between the rein¬ forced areas can possess considerably poorer tensile strength. This involves several advantages. First, the use of thick multifilament weft yarns increases remarkably the weight of the tarpau- lin. As such thick multifilament yarns are used only in relatively narrow zones while flat-film yarn is used in the zones between them, the tarpaulin is suf¬ ficiently light to be handled by a single workman who is able to cover the load easily and rapidly with re- sultant savings in labour costs. Second, the use of relatively narrow reinforced areas reduces the cost of manufacture of the tarpaulin and, as a consequence, its price, because thick multi¬ filament yarn is considerably more expensive than flat-film yarn. The cost of manufacture is largely de- pendent on the time spent on weaving. The solution ac¬ cording to the invention thus provides a tarpaulin which withstands high loads while the weight and price of the tarpaulin are optimized. The invention will now be described in more de¬ tail by way of example with reference to an embodiment shown in the attached drawings, wherein Figure 1 is a planar view of a tarpaulin ac¬ cording to the invention; and Figure 2 shows a fastening means to be used at the ends of the tarpaulin. Figure 1 shows a specific tarpaulin according to the invention. The tarpaulin 1 comprises a woven basic fabric 2 of desired shape, in this particular case rectangular. In Figure 1, the warp yarns extend in the horizontal direction and the weft yarns in the vertical direction. Reinforced areas 4 woven with relatively thick multifilament weft yarns and weaker areas 3 woven with flat-film yarn as weft yarn alternate in the basic fabric 2. The warp yarns of the basic fabric are multifilament yarns preferably thinner than those used as weft yarns in the reinforced areas. The warp yarn should, however, have sufficient tensile strength to prevent longitudinal stretching or tearing of the tar¬ paulin. As used herein, the term "multifilament yarn" refers to synthetic fibre yarn comprising at least several tens of filaments, preferably hundreds of filaments. Yarns manufactured by the multifilament technique are well known in the art. In the preferred embodiment of the invention, the multifilament yarns are made of polypropylene or polyester. Other suitable material can be used as well. The flat-film yarn used as weft yarn is also well known in the art. In the preferred embodiment of the invention, the flat-film yarn is made of high-den¬ sity polyethylene (HDPE) but other suitable materials can be used as well. If there are sharp points in the load that may tear the unreinforced areas of the tarpaulin, part of the flat-film yarns used as weft yarns in these areas can be replaced with, e.g., multifilament yarns of the same thickness as the warp yarn. For instance, every forth flat-film yarn may be replaced with a multifila¬ ment yarn. The basic fabric 2 is not usually fully water¬ proof as such but it has to be treated to obtain good water-proof properties. In the preferred embodiment of the invention, the basic fabric 2 is coated with a tough, weather-proof and water-proof plastic film. In order to reduce the weight and the price of the tarpaulin, the reinforced areas 4 are usually substantially narrower than the unreinforced areas 3. The spacing between the reinforced areas depends main¬ ly on the position and number of the fastening points in the transport means. A container bottom or platform typically comprises fastening points at intervals of 80 to 120 cm. A tarpaulin suited for such a container platform may comprise a corresponding number of rein¬ forced areas having a width of about 10 to 30 cm. How¬ ever, it is to be noted that the width, number and spacing of the reinforced areas may vary considerably in different applications. A fastening band 5 for fastening the tarpaulin to the transport means is attached to or close to one end of each reinforced area 4 by stitching or in some other way. In the preferred embodiment of the inven¬ tion, each fastening band 5 forms a loop, whereby its both ends are attached to the reinforced area 4 of the tarpaulin 1. This facilitates the fastening and tight¬ ening of the tarpaulin as another fastening band can be passed through the fastening band loop 5 and fas¬ tened to the transport means and tightened in a suit- able manner. This provides a further advantage in that when detaching the tarpaulin, this additional fasten¬ ing band can be cut off while the fastening band loop 5 attached to the tarpaulin 1 remains undamaged so that the tarpaulin can be reused if required. Of course, it is likewise possible to attach the fasten¬ ing band to the tarpaulin 1 in such a manner that it does not form a loop or in any other suitable way. Since the fastening band loops at the ends of the tarpaulin 1 strain the tarpaulin in a direction perpendicular to the reinforced area 4 and parallel to the warp yarns, the fastening bands 5 are attached to the basic fabric 2 on all sides by means of a triangu¬ lar fastening piece 6 woven of multifilament yarns, for instance. The triangular piece 6 of woven fabric is stitched onto the basic fabric 2 in such a manner that one of its sides extends in parallel with the weft yarns of the basic fabric 2, and the warp and weft yarns of the piece 6 of fabric are substantially parallel with the other two sides of the piece 6 of fabric. Both ends of the fastening band loop 5 are stitched onto the triangular piece 6 of fabric, pre¬ ferably onto a point opposite to the first-mentioned side, whereby the point load exerted by the fastening band loop 5 is transferred via the triangular piece 6 over a wider area within the tarpaulin and does not cause stretching of the tarpaulin in the longitudinal direction. The triangular piece 6 is dimensioned so as to correspond to the strength of the basic fabric. If the tensile strength of the reinforced areas is three times that of the basic fabric 2, the length of the side of the triangle 6 may be three times the width of the reinforced area 4. By means of the piece 6, the fastening bands 5 can be attached anywhere in the basic fabric. The length of the side of the triangular piece is preferably about 40 to 70 cm. A very durable triangular piece 6 of fabric is achieved by bending a square piece of fabric into triangular shape in such a manner that the warp and weft yarns of the piece 6 of fabric are diagonally positioned as described above. By means of the tarpaulin according to the in¬ vention, a load can be fastened as desired even though the tarpaulin would cover only the top of the load. In one embodiment of the invention, the basic fabric of the tarpaulin is dimensioned so as to cover the top of the load while skirt portions of a lighter water-proof weather protection material are attached by stitching or in some other way to the edges of the basic fabric so that the size of the tarpaulin is increased to such an extent that the lower part of the load will be covered as well. In this way the weight and the cost of manufacture of the tarpaulin can be further re¬ duced. The figures and the description related thereto are only intended to illustrate the invention. In its details, the tarpaulin according to the invention may vary within the scope of the attached claims.

Claims: Claims : 1. A tarpaulin (1) comprising a woven basic fabric (2) made water-proof, and several fastening means (5, 6) for fastening the tarpaulin (1) to a transport means, c h a r a c t e r i z e d in that the warp yarns of the basic fabric (2) are multi¬ filament yarns, and that areas (3) woven mainly with flat-film yarns as weft yarns and reinforced areas (4) woven with multifilament weft yarns having a greater thickness and tensile strength than the warp yarns al¬ ternate in the basic fabric in the warp direction, the fastening means (5, 6) being attached to the rein¬ forced areas (4) of the basic fabric (2). 2. A tarpaulin according to claim 1, c h r¬ a c t e r i z e d in that the reinforced areas (4) of the basic fabric (2) are narrower than the areas (3) in which the weft yarns are flat-film yarns. 3. A tarpaulin according to claim 2, c h a r- a c t e r i z e d in that the reinforced areas (4) of the basic fabric (2) are positioned at intervals of about 80 to 120 cm and that their width is about 10 to 30 cm. 4. A tarpaulin according to any of the preced- ing claims, c h a r a c t e r i z e d in that every forth weft yarn is a multifilament yarn in those areas (3) of the basic fabric in which the weft yarns are mostly flat-film yarns. 5. A tarpaulin according to any of the preced- ing claims, c h a r a c t e r i z e d in that the fastening means are fastening bands (5), at least one such fastening band (5) being attached to both ends of each reinforced area (4) . 6. A tarpaulin according to any of the preced- ing claims, c h a r a c t e r i z e d in that at least one triangular piece (6) of fabric is attached to the basic fabric on sides perpendicular to the warp yarns, the piece (6) of fabric being stitched onto the basic fabric (2) on all sides in such a manner that one side of the piece (6) of fabric is substantially parallel with the weft yarns of the basic fabric (2) and the warp and weft yarns of the piece (6) of fabric are substantially parallel to the other sides, the fastening bands (5) being attached to the triangular piece (6) of fabric onto a point opposite to the first-mentioned side. 7. A tarpaulin according to claim 6, c h a r¬ a c t e r i z e d in that the length of the side of the triangular piece (6) of fabric is about 40 to 70 cm. 8. A tarpaulin according to any of the preced¬ ing claims, c h a r a c t e r i z e d in that the multifilament yarns are polypropylene or polyester yarns and the weft yarns are polyethylene flat-film yarns. 9. A tarpaulin according to any of the preced¬ ing claims, c h a r a c t e r i z e d in that the basic fabric (2) of the tarpaulin is dimensioned so as to cover the top of the load, water-proof skirt por- tions being attached to the edges of the basic fabric (2) so as to cover the lower portion of the load.

Inventors: CEDERBLOM CHRISTER, FINELL JOHN, CEDERBLOM, CHRISTER, FINELL, JOHN
Applicants: KYMMENE OY
Application year: 1989
Main classification: B60P7
IPC codes: B60P7