IE921458A1

IE921458A1 - Tarpaulin having a perforated edge reinforcement strip

Info

Publication number: IE921458A1
Application number: IE145892A
Authority: IE
Inventors: Dieter Jablonka; Klaus Urban; Gerhard Marschitschek; Dirk Jurgensen
Original assignee: Doerken Ewald Gmbh Co Kg
Priority date: 1991-05-07
Filing date: 1992-07-01
Publication date: 1992-11-18
Also published as: GR1001168B; NO921109L; FI922041A0; PT100454A; GB9208112D0; ES2064198R; ATA62292A; FR2676484A1; NO921109D0; DE4114802C2; BE1005023A3; ES2064198B1; SE9201371L; DE4114802A1; NL9200476A; CH685618A5; DK59692A; IT1255139B; ITMI921085A1; ES2064198A2

Abstract

A tarpaulin-type cover comprises an edge-strengthening band (2) containing holes (3), the holes (3) being displaced eccentrically in the band (2) towards the edge of the cover (4).

Description

The invention relates to a tarpaulin having a perforated edge reinforcement strip.

Tarpaulins of this kind are for example used as 5 scaffolding tarpaulins. They are preferably made of woven fabrics, plastics-coated woven fabrics, plastics sheets, and plastics sheets reinforced by loosely woven fabrics, knitted fabrics, laid thread structures and matted nonwoven fabrics. Such sheets are provided with edge reinforcement strips, which are perforated to enable fastening means, for example lashing straps, tensioning ropes or the like, to be fitted. A tarpaulin of the type defined is for example known from DE 23 56 028 C3, in which perforations are provided solely in the edge reinforcement strips and these perforated edge reinforcement strips lie against the unperforated edge of the tarpaulin on one or both sides and are nondetachably joined to the tarpaulin. Other tarpaulins are also known in which, in addition to the edge reinforcement strips, the tarpaulin is also preperforated in the region of the perforations in the edge reinforcement strips. Tarpaulins are further known in which the perforations are formed by removable or ejectable parts of the tarpaulin and/or of the reinforcement strips, so that the user can open and use such perforations as desired. Tarpaulins of this kind are used not only as scaffolding tarpaulins, but also as coverings to protect materials of any kind against atmospheric conditions, or as lorry tarpaulins, as protective tarpaulins in railway and postal transport, or for many other purposes. The generic definition also includes tarpaulins which are provided in the region of the perforations with eyelets or other means strengthening the edges of the perforations, in order to improve resistance to tearing out.

When, in tarpaulins known hitherto, ropes or similar fastening means are pushed through the appropriate perforations in the edge reinforcement strips -1IE 921458 - 2 and corresponding forces occur, for example through wind loads or the like, the effect achieved is not the tearing of the perforation in question towards the edge of the tarpaulin, but the detachment of the edge reinforcement strips from the tarpaulin on the side remote from the edge of the latter; in the trade this is known as an unzipping action. This effect also occurs in the case of tarpaulins of the kind defined which have perforated edge reinforcement strips.

With this state of the art as its starting point, the problem underlying the invention is that of providing a tarpaulin having a perforated edge reinforcement strip, in which the forces occurring in the region of the perforations are introduced to an improved extent into the tarpaulin surface area, so that the so-called unzipping action is reduced or suppressed.

For the purpose of solving this problem the invention proposes alternative solutions.

A first solution is characterised in that the perforations in the edge reinforcement strip are disposed eccentrically in the latter and offset towards the tarpaulin edge adjoining the edge reinforcement strip.

Through this arrangement improved introduction of forces into the tarpaulin surface area is achieved, because the forces occurring at the perforations and edge reinforcement strips, with forces assumed to act at right angles to the tarpaulin edge, are distributed over an area extending to 45® on both sides of the line of application of the forces, and the hypotenuse of this area, formed by the relatively internally situated active reinforcement strip edge, is increased by the eccentric arrangement of the perforations in the edge reinforcement strip. With this arrangement it is basically advantageous to use a wider edge reinforcement strip than hitherto, so that the width of the region between the perforation and the reinforcement strip edge facing the edge of the tarpaulin is at least equal to that hitherto customary in the prior art, while the width of the reinforcement - 3 strip on the other side, that is to say in the direction of the tarpaulin surface area, is considerably larger. For example, the width between the perforation and the reinforcement strip edge facing the tarpaulin can be twice as great as the width between the perforation and the edge of the reinforcement strip facing the edge of the tarpaulin.

An alternative solution of the problem defined in the introduction, which can however also be applied in conjunction and in combination with the feature of Claim 1, is characterised in that in the region of the perforations the edge reinforcement strip is widened in the direction of that region of the tarpaulin which is remote from the adjoining edge of the tarpaulin.

An advantageous further development in this respect is characterised in that the width of the widened zone transversely to the longitudinal direction of the edge reinforcement strip, viewed in the plane of the tarpaulin, corresponds to at least half the width of the edge reinforcement strip in the unwidened region.

In addition, in this case provision is preferably made for the length of the widened zone to correspond to at least twice the width of the edge reinforcement strip, measured from the perforation to that edge of the reinforcement strip which is remote from the adjoining edge of the tarpaulin.

It is in particular preferable for provision to be made for the edge reinforcement strip to be in the form of a wavy line making the transition from the unwidened region to the widened zone.

Owing to the fact that in the region of the perforations provided in the edge reinforcement strip the latter is widened in the direction of that region of the tarpaulin which is remote from the adjoining tarpaulin edge, the desired improved introduction of forces into the tarpaulin surface area is achieved in this region, while the widening brings about a lengthening of the hypotenuse of the triangle of lines of force which is - 4 produced when forces occur. The width and length dimensions of the widened zone should be adapted to the selected length of the hypotenuse of this triangle. The latter should preferably correspond in length to about twice the width of the reinforcement strip, measured from the perforation to that edge of the reinforcement strip which is remote from the adjoining edge of the tarpaulin. In the preferred form of the widening having the shape of a wavy line, the force introduction line (separating line) between the edge reinforcement strip and the tarpaulin (on the side remote from the edge of the tarpaulin) is further lengthened because the wave shape results in a longer force introduction line.

In this arrangement it is in addition an ad15 vantage that, similarly to the case of a serrated formation of the reinforcement strip, material can be saved in the production of the reinforcement strip. A reinforcement strip having a wavy line or serrated shape of this kind may optionally be stamped without waste from a band strip having parallel longitudinal edges, thus forming two edge reinforcement strips shaped as mirror images of one another. These can then be joined to the tarpaulin in a manner known per se.

A further alternative solution of the problem defined in the introduction consists in that, in the region of the edge reinforcement strip and of an adjacent zone remote from the adjoining tarpaulin edge, the tarpaulin is reinforced by a reinforcement insert which is formed in or on it and joined as a plane surface to the tarpaulin and which is in the form of a laid thread structure, grid woven fabric or nonwoven fabric.

Through the inclusion of a reinforcement insert of this kind improved introduction of forces over a larger area into the actual tarpaulin surface area is achieved, since, starting from the element acting at the perforation in the edge reinforcement strip, the introduction of forces extends via the edge reinforcement strip and then via the reinforcement insert to that edge - 5 of the latter which lies in the interior of the tarpaulin.

The reinforcement insert may be disposed eccentrically in accordance with the characterising feature of Claim 1, although it is also possible to form the reinforcement insert in the manner described in connection with the edge reinforcement strip in Claims 2 to 5.

In combination with a reinforcement insert of 10 this kind it is also possible to make advantageous use of an arrangement according to Claim 1 or according to Claims 2 to 5.

A further alternative solution, which in particular is also advantageous in conjunction with Claims 6 and 7, is described in Claim 8.

A further development in this connection is characterised in Claim 9.

It has been found that tarpaulins having reinforcement inserts over the entire surface, in grid or similar form, additionally tear in particular in the edge region of the edge reinforcement strip, since the grid brings about a notch effect in that region because the structure of the grid or the like extends parallel to the edge of the reinforcement strip. This occurs particularly in those tarpaulins which are produced by first applying a grid to a plastics sheet laid out and then applying a second sheet over the grid by extrusion. This manufacturing process gives rise to the thinning of the material of the additional sheet applied by extrusion, in the regions of the threads of the grid, thus weakening the sheet and thereby increasing the risk of tearing.

If now according to the proposal of the invention a nonwoven fabric is applied to the grid structure before the extrusion of the second sheet, and if the latter is only then applied by extrusion to form the tarpaulin, the grid threads are, so to speak, coated by the covering nonwoven layer, so that the thinning of material in the region of the second sheet applied by extrusion does not - 6 10 occur or occurs only to an insignificant extent. At most the action of the extruder rollers will result in the compacting of the entire nonwoven fabric, but nevertheless a substantially even surface free from grid structures will be produced as support surface for the second sheet applied by extrusion. In principle the tendency to tear is thereby already reduced, while this effect is particularly advantageous in combination with the solutions described in Claims 1 to 7.

Examples of embodiment of the invention are illustrated in the drawings and described more fully below.

Figure 1 shows a first example of embodiment in highly schematic form in elevation, Figures 2 to 4 are similar views of other embodiments, and Figures 5 and 6 are sections of the embodiment shown in Figure 4, taken on the lines V-V and VI-VI respectively in Figure 4.

Figure 1 shows a tarpaulin 1 having edge reinforcement strips 2, in which perforations 3 are provided. The perforations 3 in the edge reinforcement strip 2 are disposed eccentrically in the latter and offset towards the tarpaulin edge 4 adjoining the edge reinforcement strip. The construction of an edge reinforcement strip known in the prior art and in use hitherto is indicated by the dashed line 5. In the prior art the perforation 3 was disposed centrally in the edge reinforcement strip 2. Substantially only the region Ll was available as force introduction line. Through the eccentric arrangement of the perforations 3 the force transmission line is extended to the length L2, it being assumed that the force is applied in the direction of the arrow K and that a field of force is formed therefrom between the 45° lines 6 with its hypotenuse formed by the edge of the length L2.

In the embodiment shown in Figure 2 in the region of the perforations 3 the edge reinforcement strip 2 is - 7 widened in the direction of that region of the tarpaulin 1 which is remote from the adjoining edge 4 of the tarpaulin. On the other hand, in the unperforated region the edge reinforcement strip 2 is not widened. The width of the widened zone transversely to the longitudinal direction of the edge reinforcement strip 2, viewed in the plane of the tarpaulin, corresponds to at least half the width of the edge reinforcement strip 2 in the unwidened region. The length of the widened zone corresponds to at least twice the width of the edge reinforcement strip 2, measured from the perforation 3 to that edge of the edge reinforcement strip 2 which is remote from the adjoining edge 4 of the tarpaulin. In the example of embodiment a preferred embodiment is illustrated in which the edge reinforcement strip 2 is in the form of a wavy line making the transition from the unwidened region to the widened zone. The resulting force introduction line is a line of the length L3, which, in comparison with the arrangement (length Ll) known in the prior art, is considerably longer, so that an improvement of force introduction and consequently a reduction of the so-called unzipping action are achieved.

In the example of embodiment shown in Figure 3 the tarpaulin 1 is reinforced, in the region of the edge reinforcement strip 2 and of an adjacent zone 7 remote from the adjoining tarpaulin edge 4, by a reinforcement insert 8 which is formed in or on it and joined as a plane surface to the tarpaulin 1 and which is in the form of a laid thread structure, grid, woven fabric or nonwoven fabric. The reinforcement insert 8 brings about improved force introduction, since with forces acting in the direction of the arrow K and with resulting force action lines 6, this force action is transmitted to the reinforcement insert 8 and thus the length L4 can be substantially regarded as reference magnitude for the force introduction line. With this embodiment a combination with the features of the example of embodiment shown in Figures 1 and 2 is of course also - 8 possible.

In Figures 4 to 6 of the drawings a tarpaulin 1 is shown which has an edge reinforcement strip 2 and which is reinforced over the entire surface by two plastics sheets 9, 10 and a reinforcement insert integrated between them and in the form of a grid 11. In the region acted on by the edge strip 2 a nonwoven fabric 12 is inserted between the reinforcement insert 11 and the second plastics sheet 10 covering the latter and is joined to the sheets by pressing. The effect thus achieved is clearly visible in Figures 5 and 6. Figure 5 shows a region of the tarpaulin 2 which is free from the nonwoven layer 12. In the production process the bottom sheet 1 is first laid out and the grid 11 is laid on it.

The sheet 10 is then applied by extrusion. In the region of the grid threads (grid 11), that is to say in the region 13, the material of the sheet 2 is weakened, so that at these points a notch action occurs when forces, particularly forces acting in the direction of the arrow K, are applied to the sheet. Figure 6 shows the region in which a nonwoven fabric 12 is laid on the grid 11. In this case the sheet 9 is once again laid out first, whereupon the grid 11 and the nonwoven layer 12 are laid on it and the sheet 10 is then applied by extrusion.

Despite the action of the press rollers no weakening occurs in the region of the threads of the grid 11, so that the tarpaulin as a whole is less susceptible to tearing in the region of the threads of the grid 11. The thickness of the nonwoven fabric 12 is preferably selected to be equal to or greater than the thickness of the reinforcement insert in the form of the grid 11.

The embodiment illustrated in Figures 4 to 6 can in particular also be used, and is advantageous, in combination with the features of the other examples of embodiment.

The invention is not restricted to the examples of embodiment, but is capable of great variation within the scope of this disclosure. - 9 All novel individual and combination features disclosed in the description and/or the drawings are considered to be integral parts of the invention.

Claims

Patent Claims

1. · Tarpaulin having a perforated edge reinforcement strip, characterised in that the perforations (3) in the edge reinforcement strip are disposed eccentrically in

2. Tarpaulin having a perforated edge reinforcement strip, characterised in that in the region of the perforations (3) the edge reinforcement strip (2) is widened 10 in the direction of that region of the tarpaulin (1) which is remote from the adjoining edge (4) of the tarpaulin.

3. Tarpaulin having a perforated edge reinforcement strip according to Claim 2, characterised in that the 15 width of the widened zone transversely to the longitudinal direction of the edge reinforcement strip (2), viewed in the plane of the tarpaulin, corresponds to at least 1¾ times the width of the edge reinforcement strip (2) in the unwidened region. 20

4. Tarpaulin having a perforated edge reinforcement strip according to Claim 2 or 3, characterised in that the length of the widened zone corresponds to at least twice the width of the edge reinforcement strip (2), measured from the perforation (3) to that edge of the 25 reinforcement strip (2) which is remote from the adjoining edge (4) of the tarpaulin. 5. 5 strip (2) is or are constructed in accordance with at least one of the characterising features of Claims 1 to

5. Tarpaulin having a perforated edge reinforcement strip according to one of Claims 2 to 4, characterised in that the edge reinforcement strip (2) is in the form of 30 a wavy line making the transition from the unwidened region to the widened zone. 5 the latter and offset towards the tarpaulin edge (4) adjoining the edge reinforcement strip (2).

6. Tarpaulin having a perforated edge reinforcement strip, characterised in that, in the region of the edge reinforcement strip (2) and of an adjacent zone remote 35 from the adjoining tarpaulin edge (4), the tarpaulin (1) is reinforced by a reinforcement insert (8) which is formed in or on it and joined as a plane surface to the tarpaulin (1) and which is in the form of a laid thread - 11 structure, grid, woven fabric or nonwoven fabric.

7. Tarpaulin having a perforated edge reinforcement strip according to Claim 6, characterised in that the reinforcement insert (8) and/or the edge reinforcement

8. Tarpaulin having a perforated edge reinforcement strip particularly according to Claim 6 or 7, which is 10 reinforced over the entire surface by two plastics sheets and a reinforcement insert integrated between them and in the form of a grid or grid laid thread structure, characterised in that, at least in the region of the edge reinforcement strip (2) and preferably in a wider region, 15 particularly in regions such as are characterised in particular in Claims 1 to 7, a nonwoven fabric (12) is inserted between the reinforcement insert (11) and the second plastics sheet (10) covering the latter and is joined to the sheets (9, 10) by pressing. 20

9. Tarpaulin having a perforated edge reinforcement strip according to Claim 8, characterised in that the nonwoven fabric (12) has at least a thickness equal to or greater than the thickness of the reinforcement insert (11).

10. A tarpaulin substantially as described herein with reference to and as shown in any one or more of the accompanying drawings.