GB2090895A - Blind - Google Patents

Abstract

The blind (1) is in its closed position tightened by an edge connection which comprises a longitudinally suspended, flexible membrane (10), which can be the blind itself interacting or cooperating with the edge (5) of a tightening moulding (3) or a loose longitudinally suspended membrane (10) interacting or cooperating with the edge (2) of the blind (1). The tightening is obtained when the blind or the membrane is pressed against the edge (5 or 2), respectively, by an air pressure difference between the outer and the inner side of the blind conditioned by the temperature difference. <IMAGE>

Description

SPECIFICATION Curtain for light and/or heat screening The present invention relates to a curtain for light or heat screening and of the type which is adapted to be positioned in a room with the front edge of the curtain displaceable along a predetermined curtain guiding track, preferably along the lower side of the roof of a greenhouse, between an open position, in which the inner air, i.e. the air in the room within the curtain guiding track, is openly connected with the outer air, i.e.

the air in the room outside the curtain guiding track, and a closed position in which the inner air is separated from the outer air by means of the curtain.

By hitherto known curtains of this type the curtain separates the inner air from the outer air when the curtain is positioned in its closed position and the movable edge of the curtain has been brought to abut a corresponding edge at the end of the curtain guiding track. In order to obtain a reasonable tightening with such an edge connection the interacting edges for the tightening must be made with large precision, and it must be ensured that the front edge of the curtain extends completely parallelly with the other edge of the edge connection in the closed position of the curtain. This calls for a large construction precision and curtain guiding precision with corresponding considerable cost of construction.

The curtain according to the invention is characterized in that in its closed position the curtain is tightened by an edge connection which comprises a longitudinally suspended, flexible membrane or lip edge and a relatively stiff rectilinear member cooperating with the said membrane or lip edge. In this way a pressure gradient or a pressure difference between the outer and the inner air is able to press the membrane or the lip edge to be tightening against the rectilinear member whereby an effective light or heat screening is obtained.In order to be flexible the membrane has of course a certain extent in its transverse direction which membrane causes the longitudinally rectilinear member cooperating with the membrane in the closing position of the curtain not to be displaced to a certain position, but only to be displaced into the area in which the flexible membrane by a pressure difference can be pressed to abut the rectilinear member in a tightening manner. The extent of this area is determined by the extent or width of the flexible membrane at the edge of the curtain.The rectilinear member can be positioned on and along the edge of the curtain if this edge is the front edge of the curtain perpendicular to the curtain guiding track, or be positioned along the opening which can be closed by the curtain, in which case the very curtain constitutes the flexible membrane which by an air pressure difference can be forced to abut in a tightening manner the rectilinear member along the opening.

The force by which the membrane is urged to abut in a tightening manner the rectilinear member increases with the pressure difference, so that the tightening of the edge connection increases with increasing pressure difference exactly when there is a need for the increased tightening of for example energy saving reasons.

The mentioned pressure difference can originate in the difference between the buoyancy in warm air and weight of cold air above curtains being stretched horizontally in consideration of the low own weight of the curtain and of the membrane.

The membrane or the edge lip can expediently be adapted to be pressed to abut in a tightening manner the rectilinear member by an excess pressure in the inner air and/or in the outer air.

This embodiment is especially suitable for horizontal curtains in greenhouses where warm inner air tends to flow upwards at the middle of the greenhouse and consequently yields an excess pressure for tightening of the curtain, and where cold outer air especially at the sides of the greenhouse tends to flow downwards and in the same way yields an excess pressure for tightening of the curtain. By inclined or vertical windows on cold days or in the night the cold air at the lowermost part of the curtain will press the curtain a little outwards away from the pane towards the interior of the room for tightening against a rectilinear member which may consist of a free edge of a U-shaped edging positioned on the frame of the window, whereby this edge as a rectilinear member cooperates for tightening with the very curtain material which then serves as a membrane.At the upper part of the window the warm inside air will press a membrane to abut the upper end of the curtain, which membrane to the frame is securely loosely suspended between its edges, and which upper end may be supported by a curtain rewinding rod which in this way constitutes the rectilinear member here interacting with the membrane for tightening of the edge connection. At the vertical sides of the window there will be an inner excess pressure at the top and an outer excess pressure at the bottom so that the side edges of the curtains are able to be tightened both ways. Furthermore a membrane which is loosely suspended between its secured edges cooperates with the very side edges of the curtain at the top of the window, while the side edges of the curtain can cooperate with the outermost secured edge of the said membrane at the bottom of the window.At the top edge, the bottom edge and the side edges of the window may e.g. be positioned a perforated Ushaped moulding in which a membrane is loosely suspended between its secured side edges. In this way is obtained a tightening with a simple frame profile member provided with a membrane where the tightening is obtained by two completely different principles dependent on the position around the window, i.e. partly between the membrane and the curtain side edge, between the membrane and curtain top and partly between the curtain side edge and the outer edge of the membrane and between the curtain bottom edge and the outer edge of the membrane.

In the following the invention will be described in more detail in connection with some embodiments and with reference to the accompanying drawing, in which Fig. 1 shows a vertical window, seen from inside and provided with a blind and a tightening lip frame according to the invention with the curtain or blind partly drawn down, Fig. 2 a section along the line Il-Il of Fig. 1, Fig. 3 a vertical window seen from inside and provided with a blind and a loosely suspended tightening membrane, Fig. 4 a section along the line lV-lV of Fig. 3, Fig. 5 a vertical window seen from inside and provided with a blind and a combined tightening lip frame and tightening membrane, Fig. 6 a section along the line VI-VI of Fig. 5, Fig. 7 a section along the line VIl-VIl of Fig. 5, Fig. 8 a section along the line VIll-VIll of Fig. 5, Fig. 9 a cross section of a greenhouse with a curtain suspended below the under (inner) side of the roof, Fig. 10 a part of a section along the line X-X of Fig. 9, Fig. 11 a detail of a known curtain edge connection, Fig. 12 a detail of an edge connection according to the invention utilized at the movable front edge of a horizontal curtain, Fig. 13 a detailed section along the line Xlll-Xlll of Fig. 12, Fig. 14 the detail of Figs. 12 and 13, seen from the top, Figs. 15 and 16 the closing member of Fig. 12 seen inclined from above and inclined from below, respectively, where the membrane for the sake of clarity is omitted, and Fig. 17 a closing member profile with a tightening lip edge.

Fig. 1 shows a curtain for light and/or heat screening of a vertical window and of the type adapted to be placed in a room, the front edge 2 of the curtain 1 being displaceable in a predetermined curtain guiding track between an open position, in which the inner air, i.e. the air in the room within the curtain guiding track, stands in open connection with the outer air, i.e. the air in the room outside the curtain guiding track, and a closed position in which the inner air is separated from the outer air by means of the curtain 1. In the case shown the curtain is a so-called blind which is drawn to a middle position between the open and closed position of the curtain. Around and along the side edges of the curtain and at the front edge of the curtain in the closed position are placed some tightening lip profiles 3 for formation of a partly closed tightening lip frame.

Fig. 2 shows a section along the line lI-Il of Fig. 1, wherein the curtain 1 is drawn to its closed position so that the front edge 2 of the curtain is situated behind the lowermost tightening lip profile 3. The tightening lip frame and the curtain 1 are mounted in such a manner that a window frame 4 is completely blinded in the closed position of the curtain and completely free in the open position of the curtain.When the temperatures of the inner air between the pane of glass and the curtain in the closed position of the curtain 1 are lower than those of the outer air in the room the cold inner air will flow downwards and out to the outer air along the edges of the curtain 1, but this is prevented by an edge connection which in this case comprises the very suspended curtain material 1 which serves as a tightening membrane, and the relatively stiff edge 5 on the tightening lip profiles 3, the edge constituting a rectilinear member cooperating with the curtain at the side edges of the curtain, which side edges act as yielding tightening lip edges, and with the curtain at the bottom edge of this, where the curtain material above the front edge 2 of the curtain is urged outwards against the edge 5 by the weight of the cold inner air.

When thereby the closed edge connection is established the curtain will seen from the interior of the room be slightly domed in the outwards direction and be tight-fitting along the edges 5.

Warm air cannot enter behind the curtain at the top when the cold inner air cannot escape through the edge connection. in this way is by simple means obtained an excellent heat screening of the window. Complete light screening can be obtained by placing a not shown pelmet at the top end of the blind. In this case the membrane is constituted by the very curtain material, and the rectilinear member is constituted by a tightening profile edge, here the edge 5 of the tightening lip profile.

Because of its larger density the excess pressure of the inner air between pane of glass and curtain urges the curtain material 1 to abut the edge 5 in a tightening manner.

Figs. 3 and 4 show the same as in Figs. 1 and 2, but of an embodiment which is particularly suited where complete heat screening is desired irrespective of the screened window being completely hermetic or not. By this embodiment the edge connection according to the invention is utilized for tightening in two different ways. To the window frame or the wall around the window 4 is here fixed a frame 7 of a sturdy wire material which surrounds the window and the curtain in its entire track length. To the frame 7 is fixed some support brackets which are bent to an L-shape and to the outer, free end of which is fixed a mounting frame in the form of a mounting wire or a stretched mounting rope, around which is fixed one side edge of a flexible membrane 10. The other side edge of the membrane 10 is attached to the frame 7 and the width of the membrane is sufficiently large for giving the membrane 10 an abundant freedom of movement between its suspended side edges. The material width of the membrane between the frames 7 and 9 is for example more than 20% larger than the distance between the frames 7 and 9. The membrane 10 is thus loosely suspended between the frames 7 and 9. In this case, however, the membrane 10 must not have that large a width that it can be wound around the curtain at its rewinding mechanism.

The membrane 10 consists of a slightly flexible material, preferably hermetic and lightproof and can consist of a so-called slip material coated with an anti-friction-coating at the side being turned against the curtain 1.

When the curtain is drawn this will take place without the membrane 10 preventing it, as the membrane is not yet affected by a pressure difference between its two sides. When the blind is completely drawn and an excess pressure prevails in the inner air between pane and curtain caused by cold or draught the curtain will be forced away from the window into abutment with the mounting frame 9 in a tightening manner. This illustrates one of the tightening ways of the curtain in the edge connection.If there is an excess pressure in the room inner air the curtain 1 will be urged away from the mounting frame 9, but at the same time the membrane 10 will be urged against the edges of the curtain by the prevailing excess pressure, i.e. against its top edge, side edges and bottom edge in order to abut these in a tightening manner, whereby the alternative way of tightening the edge connection is obtained. This situation can for example exist by a not tight window with outgoing draught. If the window is completely free of draught a third situation will exist on cold days or nights as behind the drawn curtain between this and the pane there will be established a cold air cushion and outside the curtain 1 i.e. in the room there will be warm air.In this situation the cold air will at the lower part of the curtain force the curtain 1 outwards for abutting the mounting frame 9 in a tightening manner and at the upper part of the curtain the membrane 10 will by the excess pressure of the warm air be pressed to abut the edges of the curtain in a tightening manner so that tightening will be established along the entire edge area of the curtain. Where the curtain and the membrane 10 are of a light-impervious material lightimperviousness will be obtained. The imperviousness to air flows between the inner and the outer air is of course also limited by the air imperviousness of the curtain 1 and the membrane 10.

Figs. 5-8 show a third embodiment which is also suitable for light and/or heat screening of vertical or inclined windows. Also here is used a flexible membrane 10 corresponding to the one shown in Figs. 3 and 4, but in this case along its edges the membrane is attached in a frame which is made of U-shaped profiles 12 or of the cross section shape shown in Fig. 6. The profile moulding 12 is like the frame 7 attached along the circumference of the window and is provided with ventilating openings 13 which permit air between the membrane 10 and the inner side of the moulding to escape to the inner air of the room so that the free movement of the membrane 10 will not be prevented. The same moulding 12 with the membrane 10 is used for closing of all the sides of the curtain. Tightening is obtained in the same way as by the construction shown in Figs. 3 and 4.

In Figs. 7 and 8 are illustrated the tightening ways mentioned in connection with Figs. 3 and 4. This embodiment represents a specially solid curtain edge tightening construction which will be suitable for effective light as well as heat screening.

The invention is also well suited for utilization in connection with greenhouses where the curtain with its front edge is displaceable along a predetermined curtain guiding track along the roof undersides of a greenhouse. In Fig. 9 is seen a cross section of a greenhouse, where the curtain extends both horizontally and inclinably below the underside of the roof.

Figs. 10 and 1 1 show a longitudinal section along the line X-X of Fig. 9 in which there is a number of curtain supporting lines 15 which as shown can be mounted from one house end to the other in the entire length of the house and can be supported by the supporting construction 16 of the greenhouse. The supporting lines can in pairs be positioned in a mutual distance of e.g. 1 metre in the cress direction of the greenhouse. The curtain 1 is supported on the supporting lines partly by mounting hooks 17 being adapted to be slidable easily on the supporting lines 15, partly by supporting pipes 18 supporting the front edge of the curtain, and the supporting pipes themselves being supported by curtain front edge supporting clips 19 which also are adapted to be easily displaceable along the supporting lines 15.At its front edge the curtain 1 is provided with a casing for the supporting pipe 18 which may be an aluminium pipe which extends across the greenhouse. The mounting hooks 17 may be attached in pairs to the curtain in a mutual distance of about 25 cm. The curtain front edge transporting clips 20, e.g. of nylon, are furthermore attached to the supporting pipe 18 in a suitably mutual distance, the said clips being also attached to a curtain transporting line 21 which extend in the longitudinal direction of the greenhouse, and by power-driven winding and dewinding reciprocately is able to pull the curtains in the lonitudinal direction of the house. The curtains 1 may also extend along the vertical side walls of the greenhouse.

Fig. 11 shows a detail of a known curtain edge connection in which the rear edge of a curtain 1 placed to the left is attached around a cross supporting line 22 at the supporting construction 1 6 of the greenhouse. The edge connection is closed when the curtain 1 at the right by the supporting 18 being suspended in front edge supporting clips 19 is conveyed forwards to abut the cross supporting line 22 of the transporting clips 20 on the transporting line 21. Here great accuracy is demanded of the parallelism for the supporting line 22 and the supporting pipe 18, and the transporting line 21 must be stopped in an accurate manner when the supporting pipe 18 abuts the supporting line 22.If the transporting line 21 is stopped too late there will be a risk for a damage of the transporting clips 20, displacement of these, or a breaking of the transporting line 21, and if the transporting line 21 is stopped too early there will be a risk for a great leakiness between the supporting line 22 and the supporting pipe 18.

In Fig. 12 is shown an edge connection according to the invention in which a great imperviousness of the edge connection is obtained despite the large inaccuracies in the adjustment of the parallelism for the supporting pipe 18 and the stopping of the movement of the transporting line 21. Closing fittings or support brackets 23 are here suspended in the curtain supporting lines 1 5 at the rear edge of the pair of curtains 1 shown at the left. The fittings are being kept in their shown position by a cross supporting line 22 and a cross supporting line 24. A membrane 25 is loosely suspended in the fittings 23, e.g. in the form of a curtain strip which along its edges extending across the greenhouse partly is fastened to the cross supporting line 24 and partly to the rear edge of the section of curtain 1 being positioned at the left.The section of curtain is furthermore being attached to the cross supporting line 22, which besides supports all the supporting lines 15 that are not supported by the supporting construction of the greenhouse. For securing of the edges of the membrane 25 partly to the section of curtain 1 at the left and partly to the cross supporting line 24 are preferably used staples of stainless steel which are as well used for securing the rear edge of the curtain 1 to the cross supporting line 22.

When the front edge of the curtain 1 at the right side of Fig. 12 by the supporting pipe 18, the front edge supporting clips 19, and the transporting clips 20 is conveyed to the position shown in Fig. 12 a tightening depending on the conditions being present in the greenhouse is obtained. If there are no serious differences between the tendency of the outer air, i.e. the air above the curtain, to sink or flow downwards, and the tendency of the inner air, i.e. the air below the curtain, to rise or flow upwards the two sections of curtain 1 will be tightened at the cross supporting line 24, since the curtain 1 at the right of the figure abuts this line as shown. If the tendency of the outer air of flowing downwards increases, i.e.

when the cooling of the outer air increases its specific gravity the pressure of the curtain 1 against the cross supporting line 24 will increase for increasing the imperviousness of the edge connection. If on the contrary the tendency of the inner air of flowing upwards through the edge connection, e.g. by the increasing buoyancy of the inner air deriving from the heating, the inner air will press the membrane or the curtain strip 25 upwards for abutment against the supporting pipe 18, and an increasing pressure in the inner air will increase the imperviousness of the connection.At the center of the greenhouse the buoyancy of the inner air will be particularly large and consequently the imperviousness will be obtained at the supporting pipe 1 8, while at the sides of the greenhouse the weight of the outer air will exceed the buoyancy of the inner air and establish imperviousness at the cross supporting line 24.

Also at the vertical sides of the greenhouse imperviousness will mainly be present at the cross supporting lines 24.

The situation shown in Fig. 12 is by section Xlll-Xlll of Fig. 12 shown in Fig. 13. The closing fittings 23 are seen suspended in the supporting lines 1 5 in which also the front edge supporting clips 19 are suspended. The curtain transporting lines 24 are placed on curtain transporting lines 21 between some of the curtain supporting lines 15.

Fig. 14 shows the view of Figs. 12 and 13, seen from above. The supporting pipe 18 with the curtain front edge, however, has not here been brought completely into the position as shown in Fig.12, so that the closing fittings 23 can be seen more clearly with the membrane or curtain strip 25 attached edgewise herein.

In Figs. 1 5 and 16 the fittings 23 are seen more clearly before its mounting on the supporting lines 15 and the cross lines 22, 24 with the curtain strip 25 omitted. Before the curtain strip 25 is positioned in the fitting 23 the curtain strip 25 is fixed as shown in Figs. 12 and 14 with the staples 26 also indicated in Fig. 14.As shown the fittings 23 are practically U-shaped having at one of the uneven long leg ends of the U, namely at the longest flap, a folded finger-shaped part 30, the outer point 31 of which is projecting inwardly towards a concave face or depression 32 for interaction with this, so that the curtain strip 25 with the cross supporting line 24 inserted must be a little deformed in order to be placed as shown in Fig. 12, whereafter, when the line 24 is tightened, the curtain strip 25 with the cross supporting line 24 cannot escape the space between the fingershaped part 30 and the concave face 32. In the short leg of the U a deflected part 33 with recesses is performed as shown in Fig. 1 6 for the suspension of the fitting 23 on its supporting line 1 5.In the short leg of the U a hook 34 is punched out and bent outwards in order to keep the fitting 23 attached to the supporting line 22. The function of the fitting 23 is in practice the same as the function of the support brackets shown in Figs.

-3 and 4.

Instead of using fittings 23 as shown in Figs.

1 2-1 6 in connection with cross supporting lines 22, 24 and a curtain strip 25 can be used the Ushaped closing fitting profile moulding 35 shown in Fig.17 with uneven long legs, where there is a deflected part 36 at the end of the short leg. The part 36 is during the mounting of the moulding 35 in a greenhouse intended to be provided with insertion and supporting recesses for the supporting lines 15 on the places where these are crossing the profile. At the longest leg end of the U there is a slightly deflected part 37 having a convex surface serving to abut the curtain 1 when this with its front edge supported by the supporting pipe 18 has been inserted into a position corresponding to the position shown in Fig.12. This embodiment obtains its imperviousness where the curtain 1 abuts the deflected part 37 and is well suited in cases where the cold outer air above the curtain and/or the sheet weight of the curtain 1 is predominant in relation to the buoyancy of the inner air below the curtain.In this closing profile moulding 35, however, can also be embedded a strip-shaped membrane in the same way as in the closing profile of Fig. 12, and the membrane strip can for example be a thin plastic foil which is adhered along its edges respectively to the deflected part 37 and to the bottom of the U near the short leg with an excess width in relation to the distance between the adhered edges of the membrane. In this case the moulding 35 must be provided with openings so that the inner air below the curtain can penetrate the moulding and by its pressure influence the thin membrane.

Examples of materials for the curtain 1 or the membrane 10, 25 may be clothes with or without a coating and with the designation aluporfrom A/S Fibertex, Aalborg, shade providing and energy saving webs from Ludvig Svensson AB, Kinna, Sweden, woven or extruded plastic clothes or non-woven, impregnated paper clothes.

The fittings 23 or the profile mouldings 35 may be of aluminium, stainless steel or of plastic. The same goes for the profile 3, the parts 7-9, 12 and 1 7-20. The supporting lines 15, 22 and 24 and the transporting line 21 may be massive or cable-laid steel or aluminium ropes or wires, or hemp, sisal or cotton cords possibly coated with plastic.

The fitting 23 being preferably of rustproof material, e.g. stainless steel, may also be provided with a reinforcement of the U-shaped end at the bottom part and the adjoining leg parts of the U.

This reinforcement may be in the form of a further possibly profiled U-shaped structural member being welded onto the outer surface of the Ushaped end of the fitting 23. The reinforcement may alternatively be a local increase of the U-shaped end material or merely a reinforcing profiling of the U-shaped end in order to increase its flexural strength.

Claims (9)

1. A curtain for light or heat screening and of the type which is adapted to be positioned in a room with the front edge of the curtain displaceable along a predetermined curtain guiding track, preferably along the lower side of the roof of a greenhouse, between an open position, in which the inner air, i.e. the air in the room within the curtain guiding track, is openly connected with the outer air, i.e. the air in the room outside the curtain guiding track, and a closed position, in which the inner air is separated from the outer air by means of the curtain, characterized in that the curtain (1) in its closed position is tightened by an edge connection, which consists of a longitudinally suspended, flexible membrane or lip edge and a relatively stiff rectilinear member cooperating with the said membrane or lip edge.

2. A curtain according to claim 1, characterized in that the membrane or the lip edge is adapted to be pressed to abut the rectilinear member in a tightening manner by an excess pressure in the inner air and/or in the outer air.

3. A curtain according to claim 1 or 2, characterized in that the membrane (10 or 25) is loosely suspended between its two edges, and that the rectilinear member (2 or 18) is attached to the movable front edge of the curtain (1).

4. A curtain according to any of the preceding claims 1-3, characterized in that the membrane (10 or 25) has a width which is at least 20% more than the distance between its attached edges.

5. A curtain according to claim 4, characterized in that along its two edges the membrane (10 or 25) is attached to each one of two stationary positioned, longitudinal stretched rods, lines c wires (7, 9 or 22, 24), or to each one of two longitudinal fastening areas being positioned in a mutual distance in a stationariiy placed profile moulding (12,35).

6. A curtain according to any of the preceding claims 1-5, characterized in that where the membrane (25) is loosely suspended between two stretched rectilinear members (22, 23), such as lines or wires, these members are secured in mutual distance by U-shaped support brackets or fittings (23) which in turn are suspended in lines or wires (15) extending along the curtain guiding track, one edge of the membrane (25) being connected to one (22) of the lines and sealingly connected to a stationary curtain section (1), and the other edge of the membrane (25) being wrapped or fixed around the other line (24) and maintained with the line (24) to the outer end (30) of the U-shaped brackets (23).

7. A curtain according to claim 6, characterized in that the outer end (30) of the U-shaped bracket (23) maintains the line (24) in the wrapped membrane edge to the bracket (23) by a deflected pointed part, the point (31) of which being bent inwardly in the bracket (23) and being directed towards a depression (32) at the outer end (30) of the bracket.

8. A curtain according to claim 6 or 7, characterized in that the longest leg of the Ushaped bracket (23) is almost twice as long as its shortest leg, in the outer end of which a deflected supporting flap (36) is formed for the suspension of the bracket (23).

9. A curtain according to any of the preceding claims 1-4, characterized in that the membrane (10 or 25) is secured inside a U-shaped profile moulding (12 or 35) to at least one of its side edges (14 or 37), the membrane loosely abutting the inner side of the moulding (12 or 35), the moulding where the membrane is loosely abutting the moulding being provided with at least one perforation (13) for ventilation of air between the outer side and the inner side of the moulding, and the moulding (12 or 35) at said one side edge (14 or 37) has a rounded cross section shape.