GB2115866A

GB2115866A - Double glazing

Info

Publication number: GB2115866A
Application number: GB08205060A
Authority: GB
Inventors: Ronald Ketteridge
Original assignee: CAMBRIDGE GLASSHOUSE Co L
Current assignee: CAMBRIDGE GLASSHOUSE Co L
Priority date: 1982-02-20
Filing date: 1982-02-20
Publication date: 1983-09-14
Also published as: GB2115866B

Abstract

A frame member of extruded a metal or a plastics material for tensioning eg greenhouse flexible glazing, comprises a first part 7 which, in section, has a body 9 flanges 13 extending laterally therefrom and chamfered lips 12, and a second part 8 which in section is shaped to engage closely at least over the lips when the parts are secured together with sheet(s) of flaccid material 19 disposed therebetween the sheet(s) are tensioned laterally of the member, and clamped between cooperating corrugations 14, 18. <IMAGE>

Description

SPECIFICATION Tensioning sheet material This invention relates to tensioning flacid sheet material and to double glazing and is particularly although not specifically directed to the double glazing of an existing greenhouse.

The advantages of double glazing a greenhouse are well known and where an existing structure is concerned it is most efficient to provide the extra glazing skin on the outside since this ensures that there is no air movement between the laps of existing glass panels so that these are less likely to be subject to condensation and algae growth and remain dry. It is also usually easier to alter an existing structure by providing an external skin.

Many proposals have been made for using transparent plastic film such as a polyester film and a suitable material is sold under the Registered Trade Mark "Melinex". Using such film, which typically has a thickness of say 125y, presents practical problems in erection since it needs to be stretched tightly to give optimum efficiency.

An object of the present invention is to provide two part frame members that may be used to hold opposed parts of a flacid sheet material and automatically impart tension to that material.

A further object is to provide a frame for receiving and automatically tensioning a flacid transparent plastic film material to provide a double glazing unit.

Another object is to provide an improved double glazed structure.

According to one aspect of the present invention there is provided a two part frame member each part being extruded from a metal or a plastics material, and comprising a first part which, in section, has a body and a flange extending laterally therefrom at a position spaced from one end thereof, said end having a sloped or chamfered surface extending away from the flange and a second part which in section is shaped to engage closely at least parts of the flange and the surface and means for securing the parts together with a sheet of flacid material disposed therebetween so that engagement of the second part over said surface pulls the sheet material laterally of the member.Preferably the body is -U- shaped and two flanges extend respectively outwardly from each limb the ends of which are each formed with a sloping or flanged surface and the second part is symmetrically formed to engage both flanges and both surfaces while securing means engages between the limbs. The mating surfaces of the flanges and the second part may be corrugated.

The invention also provides a glazing unit comprising rectangular frame each side of which comprises two frame members according to the preceding paragraph and a sheet of flacid transparent plastics material stretched between the parts thereof.

In addition the invention provides a double glazed structure comprising frames according to the preceding paragraph secured in spaced relationship to a glazed skin of the structure.

The above and other aspects of the invention will now be described by way of example with reference to the single figure of the accompanying drawing which shows a diagramatic perspective view of part of a frame member associated with a greenhouse.

Referring to the drawing part of a greenhouse comprises a vertical aluminium alloy glazing bar 1 and adjoining glass sheets 2 and 3. The latter are conventionally held in place by wire clips (not shown) engaging between their outer surfaces and inclined wings 4 and 5 of an outward extension 6 of the bar 1. It will be assumed that the upper end of the bar 1 extends beneath a conventional, horizontally extending, extruded gutter section (not shown) and the lower end of the bar 1 is supported on a conventional horizontally extending extruded sill (not shown).

A two part frame member has a first part 7 and a second part 8. The part 7 has a central body of -U- shape with limbs 9 separated by a slot 10 and its base 11 is extended on each side of the body. The outer ends of the limbs are thickened and formed with outwardly chamfered lips. Intermediate the lips and the base 11 flanges 1 3 extend outwardly of the limbs 9 and the surfaces 14 of the limbs are corrugated.

The part 8 is -U- shaped with a base 1 5 and outwardly inclined side walls 1 6 spaced to embrace the lips 1 2. At their outer ends the walls 1 6 are extended by flanges 1 7 the surfaces 1 8 of which are corrugated to mate with the surfaces 1 4.

Two adjoining sheets 1 9 of flacid transparent plastics film material such as that sold under the Registered Trade Mark "Melinex" so that their edge regions 20 overlap one another and extend between the parts 7 and 8.

The part 7 may be secured to the glazing bar 1 with the base 11 resting on the outer edges of the wings 4 and 5 by drilling the base and the wings between the limbs 9 and using self-tapping screws (not shown) the heads of which seat on the lips 1 2. The part 8 is secured to the part 7 by self-tapping screws 21 engaging between the limbs 9.

When the part 8 is engaged over the edge regions 20 engagement of the walls 1 6 with the chamfered lips 1 2 first slides the regions 20 into further overlapping relationship and thereafter pressing these edge regions along the limbs 9 and into the corrugations 1 4 and 1 8 stretches the sheets 19, it being assumed that opposite edge regions are similarly clamped.

In practice a series of the members may extend horizontally below the gutter extrusion and above the sill with vertically disposed members at say each alternate vertical glazing bar. Thus a series of rectangular frames is formed for receipt of the transparent film material.

Although the members are describe as "double sided" it will be understood that for the horizontal members and the end glazing bars they could be "single sided" having only one flange 1 3. In such case the body need not be of -U- shape and may have only a single limb.

At each frame corner (not shown) the members are preferably cut to provide chamfered joints but this is not essential in view of the flexible nature of the sheets 19.

Claims

1. A two part frame member each part being extruded from a metal or a plastics material, and comprising a first part which, in section, has a body and a flange extending laterally therefrom at a position spaced from one end thereof, said end having a sloped or chamfered surface extending away from the flange and a second part which in section is shaped to engage closely at least parts of the flange and the surface and means for securing the parts together with a sheet of flacid material disposed therebetween so that engagement of the second part over said surface pulls the sheet material laterally of the member.

2. A frame member according to claim 1 in which the body is -U- shaped and two flanges extend respectively outwardly from each limb the ends of which are each formed with a sloping or flanged surface and the second part if symmetrically formed to engage both flanges and both surfaces while securing means engages between the limbs.

3. A frame member according to claim 1 or claim 2 in which the mating surfaces of the flanges and the second part may be corrugated.

4. A glazing unit comprising a rectangular frame each side of which comprises two frame members according to any one of claims 1 to 3 and a sheet of flacid transparent plastics material stretched between the parts thereof.

5. A double glazed structure comprising frames according to claim 4 secured in spaced relationship to a glazed skin of the structure.

6. A two part frame member substantially as herein described with reference to the single figure of the accompanying drawing.

7. A glazing unit substantially as herein described.

8. A double glazed structure substantially as herein described.