VENETIAN BLIND

Abstract: The present invention pertains to a venetian blind (50) comprising an operating system and a plurality of horizontally disposed slats (55) suspended vertically from said operating system. In order to be suitable for use with large window panels (20) of modern high-rise building construction, the slats (55) are particularly large and stable. Each of the slats comprise an elongated hollow body made from aluminium sheet material and filled with foamed plastic material. The operating system allows flexible positioning of the support cords (60) and the stable slats (55) allow a large span between the supporting cords (60) without sagging of the slats (55).

Description: VENETIAN BLIND TECHNICAL FIELD The present invention relates to a Venetian blind comprising an operating system and a plurality of horizontally disposed slats suspended vertically from the operating system. BACKGROUND ART Screening or protective devices for walls or openings in walls with or without operating or securing mechanisms such as shutters, movable grills, screens or other constructions affording protection against light, in particular against sunshine and similar screens for privacy or appearance such as Venetian blinds as known from US-5, 906,232 and US-4, 155,395 are an integral part of contemporary fagade construction. The trend in modern high rise buildings is to use large window panels. The architectural desires lead to facades that require screens against sunlight. Most commonly conventional laminar blinds are used to provide the required shading. The size of the slats of such blinds and the maximum free span between the support ladders are, however, limited. Simply scaling up the blinds and slats would lead to various kinds of stability problems. Consequently, the Venetian blinds with the largest slats that are presently available have dimensions up to about 10 cm width and a free span between the support ladders of about one meter. The limited span between the support ladders and the consequent high number of support ladders combined with a large number of narrow slats spoil the original aesthetic effect provided by the large glass panels. Another solution has been to limit the size of the glass panels to the dimensions of the available blinds, thus limiting the architectural freedom. DISCLOSURE OF THE INVENTION On this background, it is the object of the present invention to provide a Venetian blind of the kind referred to initially, which overcomes the above-mentioned problems. This object is achieved in accordance with independent claim 1 by providing a Venetian blind that allows use of slats with dimensions that were hereto not possible. In order to increase the usable dimensions of the slats of the Venetian blind, the overall rigidity of the slats are according to the invention increased by providing slats comprising an elongated hollow body of a suitable material such as a metal or metal composite, said body being filled with a foamed material and comprising upper and lower confronting side walls extending the length of said hollow body. The rigidity of the slats are according to the invention further increased by shaping the upper side wall of the hollow body transversally convex and by shaping at least a substantial part of the lower side wall transversally concave. In practice, the above hollow body formed by said upper and lower side walls and containing said foamed material may be produced using a roll-forming technique, whereby said non-linear shape of the side walls of the hollow body and the filling of this body with suitable, foamed material during production can take place in a simple and effective manner. The Venetian blind according to the invention further allows large span between the support ladders. This object is further achieved in accordance with claim 5 by the slats comprising at least one longitudinally extending channel in the lower side wall defining an attachment location for connecting the slat to the operating system thus allowing large slats to be mounted in a secure and flexible manner. The present Venetian blind provides for slats with a width from 10 to 25 cm and more, free spans between the supporting ladders of up 2 m and more, slats with a length of 6 m and more and a height of the blind of 6 m and more. According to an embodiment of the invention, the lower side wall is provided with a plurality of perforations for improving the sound dampening characteristics of the blind. Preferable the inner side of the lower side wall is covered with a sound dampening fabric to further improve the sound dampening characteristics. According to a further embodiment of the invention, the operating gear comprises at least two parallel supporting cords or tapes spaced from each other, a plurality of coupling members connected to each of the supporting cords or tapes at spaced locations along the length thereof, the coupling members defining a coupling head at their free end that releasably engages the channels in the lower side surface of the slats, the plurality of slats being transversely disposed between the spaced supporting cords or tapes and connected to the respective pairs of coupling members. This embodiment provides a simple and reliable system for connecting the slats to the supporting cords, in a releasable manner that also allows for adjustment of the placement of the supporting cords. According to another embodiment of the invention, the supporting cords or tapes are suspended from a tilt-roll so that rotation of the tilt-roll will cause the slats to be tilted. This tilt-roll is preferably mounted on an upper non-adjustable slat. Thus, a simple and effective tilt-gear is provided. According to yet another embodiment of the invention, the operating system comprises at least two lift cords spaced from each other, the plurality of slats being disposed longitudinally between the space lift cords and preferably the lowest of said plurality of slats is connected to said lift cords, preferably by the lift cords running under said lower slat, the lift cords thus effectively being one continuos cord. Thus, a simple, reliable lifting-gear is provided that does not require perforations of the slats. BRIEF DESCRIPTION OF THE DRAWINGS In the following detailed portion of the present description, the invention will be explained in more detail with reference to the exemplary embodiments shown in the drawings, in which Figure 1 is a perspective view on a facade of a building provided with the Venetian blinds in accordance with the invention, Figure 2 is the same view with conventional Venetian blinds, Figure 3 is a side view of a Venetian blind in accordance with an embodiment of the invention, Figure 4 is a perspective view of a Venetian blind in accordance with an embodiment of the invention, Figure 5 is a detailed view of a slat and cord according to an embodiment of the invention, Figure 6 is a sectional view of a slat according to an embodiment of the invention, Figure 7 is a sectional view of a slat according to another embodiment of the invention, Figure 8 is a sectional view of a slat according to a further embodiment of the invention provided with an external sound dampening fabric, and Figure 9 sectional view of a slat according of yet another embodiment of the invention provided with gaskets. DETAILED DESCRIPTION OF THE INVENTION Figure 1 is a perspective view on a fagade 10 of a building provided with the Venetian blinds 50 in accordance with the invention. The size of the slats 55 in both width and length is in proportional agreement with the size in height and width of the window panels 20 in the wall 5 that forms the fagade 10 of the building. Typically the blinds 50 have a length of up to 6 meters and more and a width of up to 25 cm or more. The height of the blind 50 is typically up to 6 meters or more. The span between the support cords 60 that carry the individual slats 55 is typically up to 2 meters and more. The position of the support cords 60 is variable and can thus be adjusted to coincide with the posts or frames between the window panels 20. This allows the overall appearance of the Venetian blind to be in harmony with the appearance of the glass panels 20 of the fagade 10 so that the overall appearance of the fagade 10 when the blinds 50 are lowered is substantially identical with the appearance when the blinds 50 are up. Figure 2 is a perspective view on the same fagade 10 provided with conventional Venetian blinds. The distance between the ladder tapes or support cords is significantly smaller (typically less than one meter) than the width of the window panels. Therefore, the appearance of the fagade when the prior art blinds are lowered is much more fractured than without blinds and does not correspond to the appearance that the architect had in mind when designing the building. The relatively narrow width of the slats (typically less than 10 cm) means that a high number of slats is required to cover the height of the window panel and therefore, the window panel of the fagade is also highly fractured in a vertical direction, thus spoiling the appearance of the fagade even more. Further the high number of narrow slats hampers effective cleaning. Figure 3 is a side view of a Venetian blind 50 according to an embodiment of the invention in a lowered position with the slats 55 not tilted; i.e. the slats 55 are substantially in a horizontal position. In a preferred embodiment, the Venetian blind 50 includes a head rail (not shown), and a plurality of slats 55 supported on sets of two parallel support cords 60. Instead of support cords 60 it is also possible to use support tapes (not shown). In conventional blinds, the slats are supported by ladders that are formed by two parallel cords or tapes connected at right angles to each other by short strings called rungs. According to a preferred embodiment of the present invention, the slats 55 are not supported by rungs, but form themselves the rungs of the ladder as explained below. The sets of parallel support cords 60 are mounted in the head rail in a manner that enables raising of one support cord 60 while lowering the other to control tilting of the slat 55 when the blind 50 is in a lowered or partially lowered condition. According to a preferred embodiment, the lower ends of the support cords 60 are attached to the lowest slat 62 so that the blind 50 does not require a bottom rail. Two parallel support cords 60 may extend crosswise under the lowest slat 62 to form effectively one cord. According to an embodiment of the invention, a lift cord 65 extends lengthwise under the lowest slat 62 and extends upwardly along the side edges of the slats 55 into the head rail (cf. Figure 4) or into a carrying construction part (cf. Figure 3) of the fagade towards a lift motor 70. The lift motor 70 is arranged in the lifting rail in the embodiment wherein the lift cords 60 extend into the lift rail, whereas the lift motor 70 is arranged on the carrying construction when the lift cords extend through the carrying construction. As is conventional, the lift cords 65 are wound on a drum (not shown) driven by the lift motor 70. By operating the lift motor 70, the lift cords 65 can be pulled to raise the lowest slat 62 and move the slats 55 to a raised condition, and the lift motor 70 can be operated in the opposite direction in order to lower the blind 50. The free end of the support cords 60 or tapes at spaced location along the length of the slats 55 is suspended from a tilt-roll 80 driven by a tilt motor (not shown). Rotation of the tilt-roll 80 will cause the slats 55 to be tilted. The tilt-roll 80 and the tilt motor are in a preferred embodiment mounted on the upper slat 64. Consequently, the upper slat 64 is in this embodiment not tiltable. Figure 4 displays this embodiment in a perspective view. With reference to Figures 5, 6 and 7, a detailed view on a single slat 55 and a pair of support cords 60 according to further embodiments of the invention is shown. The slat 55 is provided with at least two longitudinal channels 90 in the lower side wall 57. The channels 90 provide an attachment location for connection of the slat 55 to the support cords 60. The support cords 60 are provided with coupling strings 63 at spaced locations along the length thereof. The coupling strings 63 define a coupling head 66 at their free end that releasably engages the channels 90 in the slats 55. The opening of the channel is slightly smaller than the largest cross-section of the channel 90 itself and slightly smaller than the cross-section of the coupling heads 66 of the coupling strings 63. The size of the coupling heads 66 is preferably such that they have a slightly tight fit in the channels 90. The coupling heads are preferably ball-shaped and of material with good elasticity, such as plastic or (synthetic) rubber. The coupling heads 66 can be clicked into the channels 90 and by force removed from the channels. Thus, a releasable coupling system between the support cords 60 and the slats 55 is established. Moreover, the use of a channel 90 as connecting element allows the position of the coupling head 66 to be adjusted along the length of the channel. Thereby the lengthwise position of the support cords 60 with respect to the slats 55 can be adjusted by sliding the coupling heads 66 in the channel to another position as indicated by the arrows in Figures 4 and 5. Because the support cords 60 are suspended from a tilt-roll 80 that preferably extends over the full length of the slats 55, the support cords 60 can also be slided lengthwise over the tilt-roll 80 and thus, a completely flexible positioning system for the support cords 60 is established. Therefore, the support cords 60 can be placed such that they are not in front of window panels 20 but instead can be placed according to the construction of the fagade 10 in front of the posts between the window panels 20. An appearance of the fagade 10 when covered by the blind 50 is thus created that corresponds to the appearance of the fagade 10 without the blind 50. In addition, the slats 55 cannot be unintentionally shifted by wind forces as in blinds with conventional braided ladders, thus reducing wear, noise and maintenance. The slats may be provided with further two channels (cf. Figure 5,8 and 9) which for example allow a fabric 98, such as a sound absorbing fabric to be spanned between the channels 90 for improving sound dampening characteristics of the blind or allow flexible gaskets 97 to be mounted for improving the light tightness of the closed blind. The slat 55 does not have to have four channels 90 as shown in figure 8 and 9, because the fabric 98 and/or the gaskets 97 can also be mounted in the same channel 90 that receives the coupling heads 66. Figure 6 is a sectional view of a slat 55 according to a preferred embodiment of the invention. The slat 55 comprises an elongated hollow body made from aluminium sheet material. The preferable method of producing the slats 55 is the conventional roll-forming process. The slat 55 comprises upper and lower confronting side walls 56,57 extending the length of the slat to form a tubular body. The upper sidewall 56 is transversely convex and at least a substantial part of the lower sidewall 57 is transversely concave. As shown in the embodiment according to Figure 6, the slat 55 is made of two pieces of aluminium sheet. The first aluminium sheet 51 forming the upper side wall 56 being bended at two sharp angles thus forming front and rear edges 53,54 of the slat 55. The first sheet 51 also forms a part of the lower side wall 57. At the transition between the first sheet 51 and the second sheet 52, the channels 90 for receiving the coupling heads 66 are formed. The rest of the lower sidewall 57 is formed by the second sheet 52. The first and second sheets 51 ,52 are beaded to one another. Preferably the bead and thus the transition from one sheet to the other is arranged at the channels 90. The interior of the slat 55 is filled with foamed material 85 in order to improve its stability and sound dampening characteristics. The foam 85 is according to preferred embodiment plastic foam in particular polyurethane foam. Other foamed materials such as foamed metals, in particular foamed aluminium are also suitable for filling the slat 55. Though the slat 55 is preferably made of aluminium sheet material, further embodiments comprise slats 55 made of metal sheets such as thin steel sheet and composite sheets formed of metal and non-metal sheets, in particular combinations of aluminium sheet with plastic and or fibre reinforced sheet (not shown). The construction of the slats 55 results in a stable slat that allows a large span between the pairs of support cords 60 without sagging of the slats. Thereto the stiffness as well as the compactness of the stacking of the slats 55 in the raised blind 50 has been taken onto account. According to a preferred embodiment, the lower side wall 57 of the slat, in particular the part formed by the second sheet 52, is provided with a plurality of perforations (not shown). On the inside of the slat 55, this perforated area is covered by a sound dampening fabric 95. Thus, the sound-dampening characteristics of the blind construction are further enhanced. The perforations allow part of the sound waves to be absorbed and dampened by the fabric 95 and the foam-plastic 85. Further the sheet that is preferably bonded by adhesive to the inner side of the lower side wall prevents the foamed material from penetrating into and flowing out through the perforations when filling the inner space of the slat with the loam material. Figure 7 shows an alternative embodiment in which the channels 90 and beads are located nearer to the front and rear edges of the slat. The coupling members 63 have been described as preferably being formed by strings. According to another preferred embodiment (not shown) the coupling members 63 are formed by arms made of metal or plastic. Although the blinds have been described and shown in the figures as external blinds it falls within the scope of the present invention to apply the blinds on internally or between layers of glass. LIST OF REFERENCE NUMERALS 5 wall 10 fagade 20 window panel 50 Venetian blind 51 first aluminium sheet 52 second aluminium sheet 53 front edge 54 rear edge 55 slat 56 upper side wall 57 lower side wall 60 support cord 62 lowest slat 63 coupling strings 64 upper slat 65 lift cord 66 coupling heads 70 lift motor 80 tilt-roll 85 foam-plastic 95 fabric 97 gasket 98 fabric

Claims: C L A I M S: 1. Venetian blind comprising an operating system and a plurality of horizontally disposed slats (55) suspended vertically from said operating system, said slats (55) each comprising an elongated hollow body of metal or metal-composite material and filled with foamed material (85), upper and lower confronting side walls (56, 57) extending the length of said hollow body from a front end (53) to a rear end (54), said upper side wall (56) being transversely convex and at least a substantial part of said lower side wall (57) being transversely concave. 2. Venetian blind according to claim 1 , wherein a substantial part of said lower side wall (57) is provided with a plurality of perforations. 3. Venetian blind according to claim 2, comprising a sound dampening fabric (95) covering the inside of the perforated part of the lower side wall (57). 4. Venetian blind according to any of claims 1 to 3, comprising at least one longitudinally extending channel (90) in the lower side wall (57) defining an attachment location for connecting the slat to said operating system. 5. Venetian blind comprising an operating system and a plurality of horizontally disposed slats (55) suspended vertically from said operating system, said slats (55) each comprising an elongated hollow body, upper and lower confronting side walls (56, 57) extending the length of said elongated body from a front end to a rear end (53, 54), said upper side wall being transversely convex and at least a substantial part of said lower side wall (57) being transversely concave, said slats (55) further comprising at least one longitudinally extending channel (90) in the lower side wall (57) defining an attachment location for connecting the slat (55) to said operating system. 6. Venetian blind according to any of claims 1 to 5, wherein said hollow body is made of aluminium sheet material or made of extruded aluminium material or made of composite metal and metal sheet material or metal and non-metal sheet material. 7. Venetian blind according to claim 5, wherein said hollow body is filled with foamed material. 8. Venetian blind according to any of claims 1 or 7, wherein said foamed material is plastic foam, in particular polyurethane foam, or metal foam, in particular aluminium foam. 9. Venetian blind according to any of claims 4 to 8, wherein said channel (90) is arranged proximate to said front or rear edge of the slat, respectively. 10. Venetian blind according to any of claims 1 to 9, wherein an edge of said aluminium sheet (51 , 52) material extends parallel with said elongated body and forms a joint with another edge of said aluminium sheet material, at least one of said edges being provided with a bead wrapped around the other edge. 11. Venetian blind according to claim 10, wherein said edges (53,54) of said sheet material are arranged at said channel (90). 12. Venetian blind according to any of claims 4 to 11 , wherein said channels (90) have an opening in said lower side wall (57) that is narrower than their broadest cross-section. 13. Venetian blind according to any of claims 1 to 12, wherein said operating gear comprises at least two parallel supporting cords (60) or tapes spaced from each other, a plurality of coupling members (63) connected at one end to each of said supporting cords (60) or tapes at spaced locations along the length thereof, said coupling members (63) defining a coupling head (66) at another end that releasably engages said channels (90), said plurality of slats (55) being transversely disposed between said spaced supporting cords (60) or tapes and connected to the respective pairs of coupling members (63). 14. Venetian blind according to claim 13, wherein said coupling members (63) are strings. 15. Venetian blind according to claim 14, wherein said supporting cords (60) or tapes are suspended from a tilt-roll (80) so that rotation of the tilt-roll (80) will cause the slats (55) to be tilted. 16. Venetian blind according to claim 15, wherein the tilt-roll (80) is mounted on an upper non-adjustable slat (64). 17. Venetian blind according to any of claims 1 to 16, wherein said operating system comprises at least two lift cords (65) spaced from each other, said plurality of slats (55) being disposed longitudinally between said lift cords (65). 18. Venetian blind according to claim 17, wherein the lowest (62) of said plurality of slats (55) is connected to said lift cords (65), preferably by said lift cords (65) running under said lower slat (62), said at least two lift cords (65) thus effectively being one continuos cord.

Inventors: KRAB JOERGEN, MOELLER BRENT, KRAB, JOERGEN, MOELLER, BRENT
Applicants: ART ANDERSEN AS, KRAB JOERGEN, MOELLER BRENT, ART ANDERSEN A/S, KRAB, JOERGEN, MOELLER, BRENT
Application year: 2001
Main classification: E06B9
IPC codes: E06B9