GB2467532A

GB2467532A - Roller blind system comprising two blinds with overlapping wound portions

Info

Publication number: GB2467532A
Application number: GB0901714A
Authority: GB
Inventors: David Davies
Original assignee: ENVIROTECH Ltd
Current assignee: ENVIROTECH Ltd
Priority date: 2009-02-04
Filing date: 2009-02-04
Publication date: 2010-08-11
Also published as: GB0901714D0

Abstract

A roller blind system comprises roller 26, first and second blinds 28, 29 that can be wound around and unwound from roller 26 to form overlapping wound and drop portions, respectively, and guide 38 for spacing apart the drop portions. Blinds 28, 29 are to be made of or treated with low conductivity nanomaterial, which may have morphological features such as nano-voids or nanofibres. For each turn of roller 26, the length of second blind 29 in the turn may be greater than that of first blind 28 by a predetermined amount. Guide 38 may be arranged so that the difference in length added to each blind for each turn as blinds are unwound is less that a predetermined amount. Elongate space 42 may extend along lower edges of blinds 28, 29, and may be rotatable along a longitudinal axis so that blinds 28, 29 can wrap around spacer 42. Spacer 42 may have passageways 46 to permit ariflow, and may be received in a lower channel (18, Fig 5B) which blocks passageways 46. Side frame channels (22, 24, Fig 3A) may seal and guide side edges (48, Fig 6B).

Description

TITLE

Roller blind systems

DESCRIPTION

This invention relates to roller blind systems.

In addition to blocking light, closing a conventional roller blind in a window opening of a room can also reduce thermal transmission through the window opening, partly by reflecting radiant heat, partly by reducing the convection of air across the window, and partly by reducing conduction of heat between the air in the room and the air between the blind and the window.

The convection reducing effect can be enhanced if the closed roller blind can be substantially sealed in the window opening, because the air between the blind and the window can then be substantially trapped. The conduction reducing effect can be enhanced by increasing the thickness of the blind.

The overall thermal insulation effect can also be enhanced by employing two or more overlapping roller blinds and substantially sealing the air between the blinds. Two roller blinds could be provided by two separate roller blind systems, but that would double the cost and be more obtrusive. Alternatively, two overlapping blinds could be wound onto a single roller.

However, with each turn of the roller, the two blinds would roll onto or unroll from the roller by different amounts due to the thickness of the blinds, the difference per turn being about 2t times the thickness of the blinds. Therefore, for a blind thickness of, say 0.5 mm, one of the blinds would unroll by about 35 mm more than the other blind with eleven turns of the roller.

This unequal winding of the blinds causes problems when it is desired to seal the air between the blinds. Increasing the blind thickness to enhance the conduction reducing effect exacerbates the unequal winding effect. Increasing the roller diameter to decrease the number of turns of the roller and therefore reduce the unequal winding effect makes the roller more obtrusive.

An aim of the present invention, or at least of specific embodiments of it is to deal with these problems.

In accordance with a first aspect of the present invention, there is provided a roller blind system comprising: a roller; first and second blinds that can be wound around the roller to form overlapping wound portions of the blinds, and can be unwound from the roller to form overlapping drop portions of the blinds; and an arrangement for guiding at least one of the blinds adjacent the top of the drop portions so that the drop portions are spaced apart; wherein the blinds are made of, or treated with, a nanomaterial of low thermal conductivity. By employing such a nanomaterial, the blinds can be much thinner than conventional roller blinds while still providing a significant barrier to heat conduction, and therefore the unequal winding effect can be reduced.

Preferably, the blinds have a thickness not exceeding 0.2 mm, more preferably not exceeding 0.15 mm, and even more preferably not exceeding 0.1 mm. In the case of a blind thickness of 0.1 mm, one of the blinds would unroll by only about 7 mm more than the other blind with eleven turns of the roller.

Preferably, the nanomaterial has morphological features, such as nano-voids and/or nanofibres, smaller than 100 nm in at least one dimension.

In the case where the second blind extends from its drop portion to its wound portion outside of the first blind so that, for each full turn of the blinds around the roller, the length of the second blind in that turn is greater than the length of the first blind in the corresponding turn by a predetermined amount, the guide arrangement is preferably arranged such that, as the blinds are unwound taut from the roller, the difference in lengths of the blinds added to the drop portions for each full turn of the roller is less than said predetermined amount. Therefore, in addition to the unequal winding effect being reduced by the thinness of the blinds, it is also reduced by the guide arrangement.

This feature may be provided independently of the first aspect of the invention.

Therefore, in accordance with a second aspect of the invention, there is provided a roller blind system comprising: a roller; first and second blinds that can be wound around the roller to form overlapping wound portions of the blinds, and can be unwound from the roller to form overlapping drop portions of the blinds; and an arrangement for guiding at least one of the blinds adjacent the top of the drop portions so that the drop portions are spaced apart; wherein: the second blind extends from its drop portion to its wound portion outside of the first blind so that for each full turn of the blinds around the roller, the length of the second blind in that turn is greater than the length of the first blind in the corresponding turn by a predetermined amount; and the guide arrangement is arranged such that, as the blinds are unwound taut from the roller, the difference in lengths of the blinds added to the drop portions for each full turn of the roller is less than said predetermined amount.

In a preferred arrangement, the blinds have respective lead-off portions extending between their wound portions and their drop portions, the lead-off portions being oppositely inclined with respect to the vertical. As the total thickness of the windings of the blinds on the roller varies, the inclination of one of the lead-off portions will therefore increase and the inclination of the other lead-off portion will decrease.

The system of the first or second aspect of the invention preferably further includes an elongate spacing member extending along lower edges of the blinds for holding the lower edges of the drop portions of the blinds spaced apart, preferably by substantially the same amount as is provided by the guiding arrangement, so as to assist in maintaining the drop portions of the blinds substantially parallel.

The spacing member is preferably rotatable about a longitudinal axis, and at least one of the blinds can wrap partially around the spacing member upon rotation of the spacing member.

Therefore, in addition to the unequal winding effect being reduced by the thinness of the blinds, or by the guide arrangement, it can also be reduced by allowing the one of the blinds to wrap partially around the spacing member.

This feature may be provided independently of the first or second aspect of the invention. Therefore, in accordance with a third aspect of the invention, there is provided a roller blind system comprising: a roller; first and second blinds that can be wound around the roller to form overlapping wound portions of the blinds, and can be unwound from the roller to form overlapping drop portions of the blinds; an arrangement for guiding at least one of the blinds adjacent the top of the drop portions so that the drop portions are spaced apart; and an elongate spacing member extending along lower edges of the blinds for holding the lower edges of the drop portions of the blinds spaced apart; wherein: the spacing member is rotatable about a longitudinal axis; and at least one of the blinds can wrap partially around the spacing member upon rotation of the spacing member.

The system preferably further includes a lower frame member for receiving the spacing member when the blinds are fully closed. In this case, the spacing member preferably has at least one passageway to permit air to pass through the passageway into or out of the space between the drop portions of the blinds when the blinds are being opened or closed, and the lower frame member is arranged to block the passageway(s) when the blinds are fully closed.

The space between the drop portions of the blinds is therefore vented to prevent a build-up of pressure or vacuum when the blinds are being opened or closed, but can then be sealed when the blinds are fully closed so as to trap the air between the drop portions and provide a sealed double-glazing effect.

The system preferably further includes a pair of side frame members for sealing with side edges of the drop portions. The side frame members are preferably also arranged to guide the ends of the spacing member for vertical movement and permit rotation of the spacing member.

Although reference has been made above to first and second blinds, it should be noted that the blinds may be provided by a single sheet of material or separate sheets of material.

A specific embodiment of the present invention will now be described, purely by way of example, with reference to the accompanying drawings, in which: Figure 1 is a face view of a window opening fitted with a roller blind assembly of the embodiment of the invention shown in a partly closed position; Figure 2A is a sectioned side view, taken on the section line 2-2 shown in Figure 1, with the roller blind open; Figure 2B is similar to Figure 2A, but with the roller blind closed; Figures 3A-C are sectioned views, taken on the section line 3A-3A to 3C-3C, respectively, shown in Figure 1; Figures 4A-B are views, on an enlarged scale, of the regions marked 4A and 4B, respectively, in Figures 2A and 2B, respectively; Figures 5A-B are views, on an enlarged scale, of the regions marked 5A and 5B, respectively, in Figures 2A and 2B, respectively; and Figures 6A-C are views, on an enlarged scale, of the regions marked 6A to 6C, respectively, in Figures 3A to 3C, respectively.

Referring to the drawings, a window opening in a wall 10 is fitted with a conventional window frame having top, bottom, left and right frame members 12 and glazing 14. The glazing may be provided by a single sheet of glass or by a double-glazing panel. The window may be fixed or openable. A roller blind assembly is fitted in the opening on the interior side of the window frame. The roller blind assembly has an upper roller mechanism 16, a lower channel 18, and left and right side channels 20,22.

The roller mechanism 16 comprises a housing 24 generally of box-section extending the whole width of the window opening. A roller 26 having a diameter A of, e.g., 40 mm extends through the housing 24 across substantially the whole width of the window opening. The roller 26 is mounted for rotation about its axis in a conventional fashion.

Two blinds 28,29 are fixed by their upper edges 32 in a shallow longitudinal recess 34 (see Figure 4B) in the peripheral surface of the roller 26. Each blind 28,29 has a width which is slightly less than the width of the window opening. Each blind 28,29 is thin, having a thickness B of, for example, 0. 1 mm or less, compared to the material of a conventional roller blind which usually has a thickness of 0.3 mm or more. The blinds 28,29 may be transparent, translucent or opaque; they may be plain or bear a pattern; and they may be coloured as desired.

The blinds 28,29 are formed from sheets of a nanomaterial, or provided with a nanomaterial coating, so that they have a very low coefficient of thermal conductivity. For example, as described in the patent document W02006/ 126232, the blinds may be made from fabric of natural yarns (such as cotton or wool) impregnated by a silica sol which is processed to form a silica aerogel with nano-voids having a size of the order of 100 nm. Alternatively, the silica sol may be processed to form the silica aerogel, which is then powdered and deposited on the yarn by polymeric binding. As a further alternative, short fibres may be impregnated by the silica sol which is then processed to form the silica aerogel, and then the fibres are spun. As described in W02006/126232, the thermal conductivity of the fabric is about one third of that of a similar but untreated fabric. Therefore, despite its thinness, each blind 28,29 provides a significant barrier to the conduction of heat from one side of the blind 28,29 to the other.

Rather than having nano-voids, the material of the blinds 28,29 may be treated in other ways, for example as described in Colloids and Surfaces A: Physiochemical and Engineering Aspects, vol. 300, 1 June 2007, pages 136-139, "Transport properties of fabrics treated with nano-wool fibrous materials." In that case, wool fibres are pulverised in three stages so as to produce wool particles having length of about 80 to 300 nm and a diameter or about 10 to 80 nm. A cotton woven fabric was then dipped into an emulsion of the wool particles in water, dried and cured.

Two parallel slots 36,37 are formed in the underside of the housing 24, extending almost the entire width of the window opening, so that a separating portion 38 of the housing 24, having a width C of, e.g., about 25 mm, is formed between the slots 36,37. From the roller 26, the blind 28 passes through the slot 36, and the blind 29 passes through the slot 37. The blinds 28,29 are pressed against the separating portion 38 by strips 40,4 1 of brush, sponge or rubber draught-excluder material.

At their lower ends, the blinds 28,29 partly wrap around a rod 42 in opposite directions and are fixed by their lower edges 44 in a slot formed along the rod 42. A number of through-holes 46 are formed through the rod 42 and the blinds 28,29, spaced apart along the length of the rod 42. The rod 42 has a diameter C equal to the width C of the separating portion 38 of the housing 24 of the roller mechanism 16. The rod 42 has a length which is slightly longer than the width of the blinds 28,29 and is of reduced diameter D (see Figure 6B) at its ends where it projects beyond the side edges 48 of the blinds 28,29. A pull string 50 with a knob 52 is attached to the middle of the rod 42.

The side channels 20,22 face each other and have an internal width E (see Figure 6C) which is slightly larger than the diameter C of the rod 42 plus twice the thickness B of the blinds 28,29 so that the ends of the rod 42 can slide along the side channels 20,22 (see Figure 6B). At each internal corner of each side channel 20,22, a length of brush draught-excluder strip 54 extends along substantially the whole length of the side channel 20,22 and can seal with the respective side edge 48 of the respective blind 28,29 (see Figure 6A).

The lower channel 18 faces upwardly and has an internal width E (see Figure 5A) which is slightly larger than the diameter C of the rod 42 plus twice the thickness B of the blinds 28,29 so that the rod 42 can be drawn downwardly into the lower channel 18 (see Figure SB). A length of brush draught-excluder strip 56 extends along substantially the whole length of the lower channel 18 and can seal with the blinds 28,29 on the rod 42. A notch 58 is cut in the centre of the inner side wall of the lower channel 18 to receive the pull string 50 when the blinds 28,29 are closed (see Figure SB).

The roller mechanism 16 includes a conventional arrangement for allowing the blinds 28,29 to be opened and closed. For example, the blinds 28,29 may be pulled down manually by the pull string 50 and raised by a spring arrangement, electric motor or manual winding system turning the roller 26.

It will be appreciated that with the arrangement shown in the drawings in which a turn of the inner blind 28 is rolled around the roller 26 inside the corresponding turn of the outer blind 29, each turn of the outer blind 29 will be longer than the corresponding turn of the inner blind 28 by an amount equal to about 2itB, i.e. about 0.63 mm in the case where the blind thickness B is 0. 1 mm. Therefore, if there are, say, eleven complete turns of both blinds 28,29 on the roller 26, the total wound length of the outer blind 28 will be about 6.9 mm longer than that of the inner blind 28. Accordingly, if both blinds 28,29 departed from the roller 26 at the same point, the unwound length of the outer blind 29 would increase by about 0.63 mm per turn of the roller 26 relative to the unwound length of the inner blind 28 as the blinds 28,29 were unwound from the roller. The arrangement shown in the drawings has two ways of dealing with this unequal winding problem.

First, the roller 26 is arranged relative to the separating portion 38 so that, as the blinds 28,29 are unwound from the roller 26, the distance along the outer blind 29 from a datum position F on the roller 26 to a datum position J on the separating portion 38 increases relative to the distance along the inner blind 29 from the datum position F on the roller 26 to the datum position J on the separating portion 38. In particular, in the case where the roller 26 has a diameter of 40 mm and the blinds 28,29 have a thickness of 0.5 mm, when the blind is wound up as shown in Figure 4A, the lengths along the blinds 28,29 for each turn from and to the angular datum position F on the roller 26, for the part turn from the position F to the position G or H where the blind departs from the roller 26, and from the position G or H to a datum level J relative to the separating portion 38 are as shown in the following table: 1st 126.0 126.6 2nd 127.3 127.9 3rd 128.5 129.1 4th 129.8 130.4 5th 131.0 131.6 6th ftillturnFtoF 132.3 132.9 7th 133.5 134.2 8th 134.8 135.4 9th 136.0 136.7 10th 137.3 137.9 11th 138.6 139.2 Totalfullturns 1455.1 1462.0 LastpartturnFto G 85.9 LastpartturnFtoH 65.1 LeadoffGtoJ 19.6 LeadoffHtoJ _____________ 36.0 Total last part turn and lead off 105.5 101.1 Total length in roller mechanism 24 1560.6 1563.1 By contrast, when the blind is unwound by eleven turns of the roller as shown in Figure 4B, the lengths along the blinds 28,29 for the part turn from the position F to the position G or H where the blind departs from the roller 26, and from the position G or H to the datum level J relative to the separating portion 38 are as shown in the following table: UNWOUND Inner blind 28 Outer blind 29 Totalfullturns 0.0 0.0 LastpartturnFto G 74.9 LastpartturnFto H 57.4 LeadoffGtoJ 22.3 LeadoffHtoJ _____________ 37.3 Total last part turn and lead off 97.2 94.8 Total length in roller mechanism 24 97.2 94.8 It will therefore be appreciated that the total lengths of the blinds 28,29 that are extracted from the roller mechanism upon eleven full turns of the roller 26 are given by: Inner blind 28 Outer blind 29 Total length in roller mechanism 24 when wound 1560.6 1563.1 Less total length in roller mechanism 24 when unwound -97.2 -94.8 Length extracted from roller mechanism 24 1463.4 1468.3 It should therefore be noted that, although the difference in the lengths of the blinds 28,29 wound around eleven full turns of the roller 26 is 1462.0 -1455.1 = 6.9 mm, the difference in the lengths of the blinds 28,29 extracted from the roller mechanism 24 upon eleven full turns of the roller 26 is reduced to 1468.3 -1463.4 = 4.9 mm.

The second way of dealing with unequal extraction of the blinds 28,29 from the roller mechanism 24 is provided by the ability of the rod 42 to swivel around its own axis as the blind is opened and closed. As can be seen in Figure 4A, when the blind is open, the pull string 50 is vertical. However, referring to Figure SB, when the blind is closed, the rod 42 has been allowed to rotate anticlockwise so that the pullstring 50 is inclined into and through the notch 58 in the side wall of the lower channel 18 and so that both blinds 28,29 can be equally taut.

When the blinds 28,29 are being raised or lowered, the holes 46 in the rod 42 allow air to escape from or enter the space 60 between the blinds 28,29 so that there is not a build-up of pressure or vacuum between the blinds 28,29. However, when the blinds 28,29 are closed, (i) the holes 46 in the rod 42 are substantially blocked by the draught-excluder strip 56 in the lower channel 18, (ii) the side edges 48 of the blinds 28,29 are substantially sealed to the side channels 20,22 by the draught-excluder strips 54, and (iii) the blinds 28,29 are substantially sealed to the separating portion 38 of the roller assembly 16 by the pressure provided by the draught-excluder strips 40,41. Therefore, when the blind is closed, the space 60 between the blinds 28,29 is substantially sealed so that the air in the space 60 is trapped and acts as a double-glazing insulator. The low thermal conductivity of the air trapped in the space 60, combined with the low thermal conductivity of the blinds 28,29, despite their thinness, results in significant thermal insulation of the window opening.

Although the embodiment of the invention has been described for use with a window opening, it may also be used with other building openings, such as door openings.

It should be noted that the embodiment of the invention has been described above purely by way of example and that many modifications and developments may be made thereto within the scope of the present invention.

Claims

-10 -CLAIMS1. A roller blind system comprising: a roller; first and second blinds that can be wound around the roller to form overlapping wound portions of the blinds, and can be unwound from the roller to form overlapping drop portions of the blinds; and an arrangement for guiding at least one of the blinds adjacent the top of the drop portions so that the drop portions are spaced apart; wherein the blinds are made of, or treated with, a nanomaterial of low thermal conductivity.
2. A system as claimed in claim 1, wherein the blinds are thin.
3. A system as claimed in claim 1 or 2, wherein the blinds have a thickness not exceeding 0.2 mm.
4. A system as claimed in claim 1 or 2, wherein the blinds have a thickness not exceeding 0.15 mm.
5. A system as claimed in claim 1 or 2, wherein the blinds have a thickness not exceeding 0.1 mm.
6. A system as claimed in any preceding claim, wherein the nanomaterial has morphological features smaller than 100 nm in at least one dimension.
7. A system as claimed in claim 5, wherein said morphological features include nano-voids.
8. A system as claimed in claim S or 6, wherein said morphological features include nanofibres.
9. A system as claimed in any preceding claim, wherein the second blind extends from its drop portion to its wound portion outside of the first blind so that, for each full turn of the blinds around the roller, the length of the second blind in that turn is greater than the length of the first blind in the corresponding turn by a predetermined amount, and the guide arrangement is arranged such that, as the blinds are unwound taut from the roller, the difference in lengths of the blinds added to the drop portions for each full turn of the roller is less than said predetermined amount.
10. A roller blind system comprising: a roller; first and second blinds that can be wound around the roller to form overlapping wound portions of the blinds, and can be unwound from the roller to form overlapping drop portions of the blinds; and an arrangement for guiding at least one of the blinds adjacent the top of the drop portions so that the drop portions are spaced apart; wherein: the second blind extends from its drop portion to its wound portion outside of the first blind so that for each full turn of the blinds around the roller, the length of the second blind in that turn is greater than the length of the first blind in the corresponding turn by a predetermined amount; and the guide arrangement is arranged such that, as the blinds are unwound taut from the roller, the difference in lengths of the blinds added to the drop portions for each full turn of the roller is less than said predetermined amount.
11. A system as claimed in claim 9 or 10, wherein the blinds have respective lead-off portions extending between their wound portions and their drop portions, the lead-off portions being oppositely inclined with respect to the vertical.
12. A system as claimed in any preceding claim, further including an elongate spacing member extending along lower edges of the blinds for holding the lower edges of the drop portions of the blinds spaced apart.
13. A system as claimed in claim 12, wherein the spacing member is rotatable about a longitudinal axis, and at least one of the blinds can wrap partially around the spacing member upon rotation of the spacing member.
14. A roller blind system comprising: a roller; first and second blinds that can be wound around the roller to form overlapping wound portions of the blinds, and can be unwound from the roller to form overlapping drop portions of the blinds; an arrangement for guiding at least one of the blinds adjacent the top of the drop portions so that the drop portions are spaced apart; and an elongate spacing member extending along lower edges of the blinds for holding the lower edges of the drop portions of the blinds spaced apart; wherein: -12 -the spacing member is rotatable about a longitudinal axis; and at least one of the blinds can wrap partially around the spacing member upon rotation of the spacing member.
15. A system as claimed in any of claims 12 to 14, further including a lower frame member for receiving the spacing member when the blinds are fully closed.
16. A system as claimed in claim 15, wherein the spacing member has at least one passageway to permit air to pass through the passageway into or out of the space between the drop portions of the blinds when the blinds are being opened or closed, and the lower frame member is arranged to block the passageway(s) when the blinds are fully closed.
17. A system as claimed in any preceding claim, further including a pair of side frame members for sealing with side edges of the drop portions.
18. A system as claimed in claim 17 when dependent on directly or indirectly on claim 13 or 14, wherein the side frame members are arranged to guide the ends of the spacing member for vertical movement and permit rotation of the spacing member.
19. A roller blind system substantially as described with reference to the drawings.