GB2031497A - Cover of sheet form - Google Patents

Abstract

A cover comprises a stretched sheet of plastics film 1 of high elasticity and clinging capability. A carrier element 4 is provided with of one or more surfaces of material 3 to which the stretched sheet of plastics film clings, forming a durable joint which, however, can be opened and re-sealed without substantial damage to the joining surfaces. Thermal insulation may be obtained by covering an existing window, alternatively the cover may be used on a light filter over a display window. <IMAGE>

Description

SPECIFICATION Thermal insulation systems Existing thermal insulation systems incorporating plastics in nonrigid sheet form, which are used primarily in lieu of expensive double glazing to reduce heat losses through windows, suffer from a number of serious drawbacks which tend to inhibit a wider use of such systems.

For example, there is no method devised and in use by which nonrigid plastics sheets can be fixed cheaply, simply, effectively and neatly to a window assembly, or to certain carrier elements which in turn are then inserted into the window space or are attached to window elements (e.g. frames, panes).

Again, the view through windows provided with existing thermal insulation systems incorporating nonrigid plastics sheet elements usually is grossly distorted as a result of sagging, ripples, crinkles etc. of the plastics sheet elements. Thicker plastics sheeting which is less prone to such defects is more expensive and has a lower transparency; its fixing also tends to be difficult.

Similarly, replacement of a damaged or soiled plastics sheet element in existing thermal insulation systems is usually connected with difficulties arising from the fact that permanent joints are at present used with such elements.

The objective of the present invention is to provide a low-cost, yet thermally effective and esthetically acceptable alternative to conventional double glazing systems, which is free from the major shortcomings of existing systems mentioned above.

This invention, in addition to its major application to windows, can be extended for use in other fields. For example, it can be used to provide additional thermal insulation to greenhouses, to reduce heat losses through building walls, to provide cloches and similar devices used in gardening practice. It can be used to provide cheap additional thermal insulation of solar heat collecting devices, and may be applied to numerous other situations where thermal insulation is required. The invention is based on the use of certain properties of certain types of plastics materials exemplified by the so-called stretch and cling films.One such material is being produced by Filmco International Inc., Salters Lane, Sedgefield, County Durham, under the names MEAT WRAP and MEAT WRAP 'F', in a range of thicknesses including 65 gauge and 100 gauge, and in a range of roll widths including 52 inches.

The properties of such a material relevant to the invention are: high transparency, high elasticity, and capability to cling itself and similar materials but not to other materials commonly encountered in everyday life. This selective clinging property is especially important, and will be examined in more detail as a preliminary to the description of the invention.

The term 'cling film' will be used in the following to denote any material possessing properties similar to those listed above.

A durable joint capable of taking up considerable tangential forces F can be formed by overlapping the edge portions of two cling film sheets 1 and 2 as shown in Fig. 1. These tangential forces, after sufficient normal pressure has been applied to the joint being formed by the contacting surfaces, are adequate to maintain the cling film sheets thus joined in tension without noticeable sag. At the same time the joint can be easily opened by application of tensile forces normal to the contacting surfaces. It can be rejoined, for example, after appropriate relative positonal adjustments of the sheets to remove ripples in sheets as a results of uneven tensioning of parts of the sheets.

In Fig. 2 a cling film sheet 1 is joined to a strip 3 of cling film, or a material with a similar 'clinging' capability, attached in some manner to or forming a part of a carrier element 4. Such a carrier element may be a part of a structure capable of taking up forces, or it may act as a transferrer of forces to other structures, without itself possessing adequate stiffness to sustain these forces.

In the joint shown in Fig. 3 the sheet 1 has a portion 5 going around a corner for an increased joint strength. In Fig. 4 a round carrier element is shown; in both cases element 3 of cling film or similar material may cover the entire circumference of the carrier element 4 or only a part of its circumference.

Again, the entire carrier element may be made of a material having 'clinging' properties.

Figures 2 to 4 embody the basic idea underlying the invention: instead of a cling film sheet being permanently glued or otherwise permanently attached to an item such as a window frame, for example, the item in question is provided with a cling film element, either directly or via a carrier element, and a durable yet easily separable and re-joinable connection is formed between the cling film sheet and the cling film element. A variety methods can be used to fix the carrier element with a cling film element to the item which is to be provided with the thermal insulation system. Nailing, glueing, screwing, stapling are examples of such methods.

According to the invention there is provided a thermal insulation system comprising a carrier element of one of the kinds defined herein and a cling film sheet or a plurality of such sheets stretched over the said carrier element which possesses a surface or a plurality of surfaces to which the said cling film sheet or plurality of sheets clings and forms a durable yet easily openable and rejoinable draft-proof joint or plurality of such joints capable of taking up the tensile forces inherent in the said stretched film sheet or plurality of sheets; a cling film material, or any other material to which cling film material clings, may be used to provide the said carrier element with a surface or a plurality of surfaces with which the said stretched cling film sheet or plurality of sheets is to make a durable joint or a plurality of such joints.

It is understood that the method inherent in the invention is applicable to other fields besides thermal insulation. For example, lightfiltering protective systems used for display windows can be attached in the same manner.

Specific embodiments of the invention will now be described by by of example, with reference to the accompanying drawings (commencing with Fig. 5) where desirable for the sake of clarity and/or brevity.

Figure 5 depicts a thermal insulation system applied to a large window pane 7 in a frame 6; the carrier element 8 of the system, carrying the cling film stretched sheet 9, is attached to the pane, for example, by adhesive (the carrier element and adhesive may be transparent materials).

Figure 6 shows the cross section of an alternative carrier element 8 for this type of application of the thermal insulation system.

Here the body of the carrier element is made of two regions 1 1 and 12, the former being relatively stiff and the latter more elastic. The region 12 is provided with a series of depressions which function as suction cups when the carrier element is pressed against the pane and released. The stiffer region 11 is provided with a cling film strip 10 forming a joint with the stretched cling film sheet 9.

Figure 7shows a unit of a thermal insulation system with two stretched cling film sheets 9 and 9A. The carrier element 8 is provided with with an elastic sealing element 14.

Figure 8 shows the cross section through the edge of the unit shown in Fig. 7. The carrier element in this instance is a channel section provided with surfaces outside and inside the channel to which the cling film sheets adhere. The sealing element 14 is shaped to exert pressure to portions of the sheets 9 and 9A, in order to increase the joint strength between the carrier element 9 and the said sheets.

Figure 9 depicts the method of applications of thermal insulation units of the kind shown in Fig. 7. Here the sealing element, being elastic and having been compressed in the window space, ensures that the insulation units are kept in position in the window space. However, the stiffness and dimensions of the sealing element are chosen so that the insulation units can easily be removed from or repositioned in the window space.

Figure 10 shows an alternative to the arrangement in Fig. 8 for the same type of application of thermal insulation units. Here the carrier element 8, which may be T-sectioned timber or plastic (e.g. rigid light-weight foam, with appropriate surface treatments to seal pores), is provided with surfaces 10 and 1 0A to which the stretched cling film sheets 9 and 9A cling. The sealing (and fixing) element may have a cross section as shown, or it may have some alternative form, dependent on the particular conditions of application (e.g. the contour of the surfaces around the window space).

Figure 11 shows a possible corner piece 15 of carrier element frames, with holes 16 for dowel pins, while Fig. 12 shows such a corner piece joined to members 17 and 18 of such frames.

Figure 13 illustrates another method of application of a thermal insulation system. Here the carrier element frame 8 is larger than the opening accommodating the window. This frame is provided with a face seal 20 running along its three sides, and a peripheral seal 19 running along its bottom side. The frame is held against the wall (the method of holding not shown), so that a draft-proof connections are made with the wall (by the seal 20) and with the window ledge (by the seal 19).

Figure 14 depicts examples of devices which could be attached to carrier elements or act as carrier elements themselves. They can take the form of an elongate objects (strips, filaments) with appropriate mechanical properties. They consist in principle of the surface 21 to which cling film clings, the substrate 22 for strength, stability and shape requirements, the adhesive layer 23, and possibly a protective layer 24 (e.g. paper) which can be peeled off before application of such devices.

Figure 15 shows another example of devices which may be attached to carrier elements or which can function as carrier elements. Here countersunk holes are provided for fastening (screwing, nailing) purposes. A sealing strip 25 is provided to ensure a draftproof connection between the device and the item to which it will be fixed.

Figure 16 represents an example of distance pieces, consisting of a body 27 and layers 21 and 21A of material to which cling film clings.

Figure 1 shows an application of a capping piece, which consists of a body 28 with appropriate mechanical properties and surface (or layer) of material to which cling film clings. Its purpose is to increase the strength and stability of the joint made between the layer 10 of cling film material on the carrier element 8 and the stretched cling film sheets 9 and 9A.

Figure 18 shows a capping piece, where the body 28 is provided with the surface 21 to which cling film clings; additionally countersunk holes 26 are provided for added me chanical fixing of such capping pieces.

Figure 19 shows (in a cross section) a possible use of a capping piece 31, a distance piece 30 and a device exemplified by Figs. 14 and 15 attached to the carrier element 8 (or to a part of the item which is to be provided with a thermal insulation system. As is see from this figure, there are two cling film sheets, 9 and 9A, with an air layer between them, incorporated for added insulation. It can be seen, however, that by the use of additional distance pieces the number of cling film sheets can be increased in such a system.

Figure 20 depicts in cross section of a joint where the capping piece is made of permanent magnetic material such as, for example, magnetic rubber, while the carrier element is made of magnetically responsive material (e.g.

steel). The purpose of this is to increase the strength and stability of the joint between the cling film sheet 9 and the layer 10 to which cling film clings.

Figure 21 shows timber sections provided with surfaces to which cling film clings. These surfaces may be smooth or they may have various relief patterns such, for example, knurling and serrations. Fig. 22 shows elements of cling film sheets (strips, bands, patterns such as annuli etc.) provided with adhesive layer 23 and an protective (peel-off) layer 24. The surface may be smooth or it may knurled or provided with other patterns. Again it may be provided with ridges 33 to make more manageable when applying them to surfaces which have to make joints with cling film for variety of purposes.

Figure 23 shows a possible method of fabricating a thermal insulation unit. Here the carrier frame is laid flat and the roll 35 of cling fim sheeting is unrolled over it, pressing the unrooling material into close contact with the carrier element 8. Unless the roll 35 contains sheeting which is specifically pretensioned, the cling film material thus attached to the carrier element is not adequatly tensioned.

To overcome this, when the required length has been cut off from the roll, the joints formed must be undone and remade with the required tension applied to the sheet. In the same way possible ripples in the stretched sheet can be removed. When the sheet is stretched and without wrinkles, the superfluous edges are cut off, the carrier frame is turned over and the process repeated for the other side. The property of the cling film of not clinging to most of the other materials allows the fabrication process to be carried out in most surroundings.

Figure 24 illustrates the use of the invention in providing thermal insulation to a greenhouse. Here the greenhouse frame 36 has been provided with carrier elements of the type exemplified by Fig. 18. Cling film sheeting is applied from an appropriately dimensioned roll 35.

Greenhouses can entirely be made of carrier elements 38 and, say, two cling film sheets 9 and 9A as indicated diagrammatically in Fig 25.

Figure 26 represents an exploded view of the details of such a greenhouse construction.

The carrier frame 38 is provided with an inner cling film sheeting 9, a distance piece 30, an outer cling film sheeting 9A, and a capping piece 31.

Figure 27 shows the use of the invention to provide insulation to a solar heat collector 39 provided underneath with conventional thermal insulation layer 40. The top which must be accessible to sunlight is provided with two cling film sheets 9 and 9A strecthed respectively over carrier elements 8 and 8A.

Figure 28 shows a sheet of some other material (e.g. a light filter) provided with a cling film border 41, to allow the fixing techniques described herein to be applied to it, to ensure a distortion-free through such a sheet 42.

Figure 29 depicts another variant in the construction of a thermal insulation unit consisting of a frame made up of carrier elements 8 and 8A, cling film sheets 9 and 9A with an air gap between them, an elastic compressible layer 43 between the carrier elements, and channel section 44 to hold the assembly thus formed together.

Figure 30 shows a thermal insulation unit of similar construction, having four cling film sheets with three air gaps between them. The method of construction described in its application to thermal insulation systems can obviously be used for other purposes, such as for sealing containers against dust, insects and other pollutants. For example an element 45 depicted in Fig. 31 can be used to attach cling film sheets over an open-top container.

Such an element 45 consists of an appropriately shaped carrier layer 22 with required mechanical properties (e.g. stiffness, elasticity) and layers of cling film or similar material.

Figure 32 shows an application of the element 45 to a tray 46 with vertical sides.

There is an overlapping portion 47 of the element 45 where the layers 21 and 21A cling to one another. In other cases especially manufactured elements 45 are used. An example of such element could be a closed loop which fits around a car fog light, allowing a protective cling film sheet to be stretched over the light to prevent it from being covered with dirt dead insects etc. A similar arrangement may be used to protect car windscreens or roofs, when parked under trees for example, from droppings of birds etc.

Finally, it is understood that all conventional methods used with cling film sheets to form permanent joints, such as, for example, use of heat, can be applied to make the joints in the thermal insulation systems described and in other applications permanent. It is also under stood that conventional frame and sealing methods used with conventional double glazing systems may be used with thermal insulation systems according to the invention. However, since the weight of such systems is very low in comparison with glass units, the supporting frame systems can be made of lighter sections and less strong materials such as, for example, plastics of various kinds.

Claims (13)

1. A method of producing constructions incorporating at least one stretched sheet of plasticised polyvinyl film or film of any other material with similar properties of elasticity and selective clinging, in which means for producing durable but re-openable joints with the said sheet are provided by a carrier element of material furnished with means of attachment to or means of incorporation into the said constructions-the said carrier element being characterised by the presence of a surface or a plurality of surfaces of plasticised polyvinyl chloride or any other material with similar selective clinging property, with which the said stretched sheet forms a joint, by virtue of the clinging property, which can reopened and closed more than once without substantial deterioration of the joining surfaces.

2. A thermal insulation system obtained by the method of producing constructions as claimed in claim 1, in which the said stretched sheet of film is a material marketed by Filmco International Inc., Salters Lane, Sedgefield, Cotsnty 3urham, under the name MEAT WRAP, and the respective surface or plurality of surfaces of the said carrier element is of the same material.

3. A carrier element of material as claimed in claim 1, having an elongate form of arbitrary cross section and provided with means of attachment to other bodies.

4. A carrier element of material as claimed in claim 1, of an elongate form and arbitrary cross section, possessing strength and stiffness which are adequate for use of the said carrier element in the manufacture of frames capable of supporting, without substantial deflections, the said stretched sheet of film.

5. A carrier element of material as claimed in claim 3, in which the said means of attachment to other bodies are mechanical, such as screws, nails, staples, clips, and a sealing strip is provided on the side of the carrier element next to the body to which it is to be attached.

6. A carrier element of material as claimed in claim 3, in which the said means of attachment are adhesive, in the form of a layer or a plurality of parallel layers provided with a protective layer of material which is removable prior to attaching the said carrier element to a body.

7. A carrier element of material as claimed in claim 3, in which the said means of attachment are magnetic, such as permanent magnetic elements.

8. A carrier element of material as claimed in claim 7, in which the said permanent magnet elements are flexible strips of magnetised barium ferrite-loaded rubber or plastics material.

9. A carrier element of material as claimed in claim 3, in which the means of attachment are vacuum cup type devices capable of adhering to smooth surfaces of dense material such as, for example, glass window panes.

10. A carrier element of material as claimed in any of the preceding claims, in which the surfaces with clinging property are provided with relief patterns such as, for example, knurling, to promote the formation of a durable joint between these surfaces and the said stretched sheet of film.

11. A carrier element of material substantially according to the description herein with reference to the attached drawings.

12. A thermal insulation system substantially according to the description herein with reference to the attached drawings.

13. A method of producing constructions incorporating at least one stretched sheet of film, substantially according to the description herein with reference to the attached drawings.