GB2028233A

GB2028233A - Plastics structural element

Info

Publication number: GB2028233A
Application number: GB7929197A
Authority: GB
Original assignee: Plastic und Form Kunststoff Verarbeitungs GmbH
Current assignee: Plastic und Form Kunststoff Verarbeitungs GmbH
Priority date: 1978-08-22
Filing date: 1979-08-22
Publication date: 1980-03-05
Also published as: NL7906358A; DE2836634A1; AT365268B; BE878374A; FR2434031A1; FR2434031B3; DE2836634C2; ATA561579A; IT7925218A0; IT1122842B

Abstract

A single or double-layer structural element made of plastics material and having an appreciable area, which element has a plurality of mutually parallel rigid ribs 1, which are connected, at at least one of their ends, to a foil or foils 2 having a thickness substantially smaller than that of the ribs 1, which may be unitary with a foil. <IMAGE>

Description

SPECIFICATION Plastics structural element The invention relates to a single-layer or doublelayer structural element made of plastics material and to a method of producing such elements. The element is particularly intended for use in constructions which are required to have good insulation properties, considerable transparency and low weight, and may have to be arranged along curves, and which are of relatively low cost.

It is known to produce sheets and panels having a very large number of different cross-sections by the extrusion method, the material being cooled in a sizing zone after leaving the die. In the production of such sheets, the flow behaviour of the plastics materials makes it necessary to maintain certain minimum wall-thicknesses, and high tool and machine costs have to be incurred, particularly in the production of box and other hollow sections. Such structural elements are therefore of necessity made from a uniform material, having a certain colour four each particular case. Because of the necessary relatively great wall-thicknesses, such constructional elements cannot easily be used for forming curved surfaces either.

The present invention seeks to provide singlelayer or double-layer structural elements which do not suffer from the above-mentioned disadvantages and which, in particular, are considerably cheaper two produce.

According to a first aspect of the invention, there is provided a single-layer or double-layer structural element made of plastics material and comprising a plurality of mutually parallel rigid ribs 1 each connected, at at least one end, to a foil having a thickness substantially smaller than that of the ribs.

If a thickness of less than approximately 100 y is selected for the foil, then a structural element is obtained that is substantially rigid in the direction along which the ribs extend, but is deformable in the direction transverse of the ribs, so that the structural element can be adapted to suit any curvature imposed by a supporting construction and can be transported in a rolled state. The structural element is therefore particularly suitable for covering hothouses and artificial swimming pools, as well as in the construction of tents and as rigging for supporting the covers of lorries.

The considerably reduced cost of producing such structural elements results from the fact that the ribs, optionally combined with a continuous transverse connection, can be produced by the extruder method, whereupon the thin foil is welded on to the ribs while they are still in the plastic state.

According to a second aspect of the invention, there is provided a method of producing the structural element according to the invention, said method comprising extruding from a die a plurality of ribs having an angled cross-section and connecting said ribs, while still in the plastic condition, to at least one deformable foil which is welded on to them.

To enable two structural elements to be interconnected in a simple manner and, if so required, at the site where they are to be used, the outer ribs at each end of one of the structural elements are so formed that they can be hooked to the terminal rib of an adjacent structural element. For the purpose of interconnecting two structural elements, each rib may be of a rail section having a dovetail groove into which the free ends of the foil of two structural elements are fitted and clamped by means of a clamping bar which is of substantially T-shaped cross-section and has a resilient pear-shaped central web.

In order that the invention may be better understood various different embodiments thereof will now be described by way of example only and with reference to the accompanying drawings in which Figures 1 to 8 each show a side sectional view of one embodiment of a structural element in accordance with the invention in the form of a panel.

In the structural element illustrated in Figure 1, a thin foil 2 is welded on to each of the T-section ribs t.

Figure 2 shows a connection between two structural elements of the type shown in Figure 1, the outer ribs 3 and 3' of which are of substantially U-shaped cross-section which enables the two elements to be hooked together.

In the structural element illustrated in Figure 3, a thin foil 2 is welded to the tops and bases of a plurality of I-section webs 1.

Figure 4 shows a connection between two structural elements of the type shown in Figure 3. The overlapping ends of the foils 2' of one element are welded on to the foils 2 of the other element in the region of a rib 1.

In the example shown in Figure 5, a hollow section 4, inserted between the ribs 1, is used for interconnecting two structural elements, the foils 2 and 2' of which overlap and are welded together.

Figure 6 shows a connection between two structural elements in which the free ends of the foils 2 and 2' are laid in a respective dovetail groove in a double U-section element 5 and are pressed into this section and against its limbs by means of a resilient clamping bar 6 having a T-shaped cross-section. The free ends of the foils 2 and 2' are thus clamped between the resilient central web of a respective clamping bar 6 and the limbs of the element 5.

In the structural element shown in Figure 7, the extruded section comprises a plurality of T-section ribs 1, which are interconnected by means of a layer 7 of plastics material forming the outer wall of the structural element, whereas the inner wall of the element is formed by a foil 2 welded on to the ribs.

Such a structural element which is likewise bendable, though to a lesser extent, is particularly suitable, because of the greater strength and impactresistance of its outer wall, for forming the outer surface of constructions subjected to severe weather conditions or high wind pressure.

Figure 8 illustrates an element of symmetrical construction, the ribbing of which is formed by a plastics layer 8 which is disposed in a central plane and on each side of which is arranged T-section ribs 1 on to which foils 2 are welded.

Claims

1. A single-layer or double-layer structural element made of plastics material and comprising a plurality of mutually parallel rigid ribs 1 each connected, at at least one end, to a foil having a thickness substantially smaller than that of the ribs.

2. A structural element according to claim 1 wherein the foil is deformable.

3. A structural element according to either of claims 1 or 2 wherein the rigid ribs each have an L-, T-, I-, or U- cross-section or a box cross-section.

4. A structural element according to any one of claims 1 to 3, wherein the ribs are produced by extrusion.

5. A structural element according to any one of claims 1 to 4 wherein the ribs are produced by extrusion in the form of a one-piece extrusion comprising the ribs and interconnecting material in sheet form.

6. A structural element according to any one of claims 1 to 5 wherein the ribs at at least one outer edge of a structural element have a U-shaped cross-section with limbs of unequal length, so as to enable elements to be interconnected one with another.

7. A structural element according to any one of claims 1 to 6 wherein each end of each of said ribs is connected to a respective one of a pair of said foils, such that the ribs are sandwiched between the foils.

8. A structural element according to any one of claims 1 to 6 wherein the foil or foils project beyond the edge ribs.

9. A structural element according to any one of claims 1 to 8, wherein the edge ribs have recesses open at their edges which serve as latching means for the anchoring element of a supporting construction.

10. A structural element according to any one of claims 1 to 9 wherein the two edge ribs of two abutting structural elements are formed by the limbs of a double U-section element, interconnecting the two structural elements, which limbs form a pair of dovetail grooves, the two structural elements enclosing the resilient, outwardly widening central web of a clamping bar of T-shaped cross-section.

11. A structural element made of plastics material substantially as hereinbefore described with reference to any one of the accompanying drawings.

12. A method of producing a structural element as claimed in any one of claims 1 to 11 comprising extruding from a die a plurality of ribs having an angled cross-section and connecting said ribs, while still in the plastic condition, to at least one deformable foil which is welded on to them.