Abstract:
There is described a portable and foldable window blind comprising an sheet ( 1 ) of light-attenuating material having a resilient flexible frame ( 2 ) attached around its edge, the blind having fixing means ( 5 ) for attaching to a window, and the fixing means being attached to the sheet material of the blind by an elongate element ( 4 ). The elongate element ( 4 ) is preferably a flexible tension element such as a cord or strap, and may be elastic. The effective length of the elongate element ( 4 ) between the sheet ( 1 ) and the fixing device ( 5 ) may be adjusted by a clamping device ( 7 ) positioned on the side of the sheet material ( 1 ) remote from the fixing device ( 5 ) and selectively engagable at a variety of points along the length of the elongate element ( 4 ). There is also described an extension piece ( 26,27,28 ) for mounting the blind to a bay window.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of co-pending International Application No. PCT/GB2009/002943 (filed on Dec. 22, 2009 by the same inventor and designating the United States of America), which claims priority to British Application Serial No. 0900121.5 (filed on Jan. 6, 2009 by the same inventor) and to British Application Serial No. 0917172.9 (filed on Sep. 30, 2009 by the same inventor), all three of which are incorporated herein by reference in their respective entireties. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to window blinds, and particularly concerns a blind or blackout for substantially preventing light from entering a room through a window to which the blind is mounted. 
         [0003]    Many people, particularly babies and children, sleep better in a dark environment, particularly if they are accustomed so to do. Some parents fit blackout curtains in children&#39;s rooms, so that the children will not be woken by the dawn, particularly during the summer months. However, when on holiday or temporarily staying away from home, the curtains or blinds at the destination may not provide such a darkened environment for children to sleep. Curtains which admit light may cause children to wake at a much earlier hour than customary, which can be both inconvenient for the parents, and detrimental to the children&#39;s alertness and humour during the ensuing day. 
         [0004]    There therefore exists a need to provide a device which can be deployed to substantially prevent the passage of light through a window, in order to darken a room and thus promote longer periods of sleep. Preferably the device is readily portable, to enable parents to carry the device with them when travelling. 
       SUMMARY OF THE INVENTION 
       [0005]    According to the invention there is provided a window blind comprising a flexible sheet of substantially light-proof material having a resilient flexible frame adapted to impose a tensile stress in the sheet, the blind further comprising a number of fixing arrangements each comprising a fixing device adapted to be attached to a window, the fixing device or devices each being attached to the sheet material by means of an elongate element, preferably a flexible tension element, and wherein the effective length of the elongate element between the sheet material and the fixing device is adjustable. 
         [0006]    The fixing devices are preferably attached to the sheet material at locations spaced from the edge of the sheet, so that when the fixing devices are attached to a window pane the sheet material may extend laterally beyond the window and engage the surface of the wall surrounding the window. 
         [0007]    The flexible sheet material may be a rubberised fabric material, a dense non-woven fabric, or a closely-woven fabric material. The sheet material does not have to prevent all light from passing through the sheet into the room, and may permit the passage of a part of the incident light. However, in at least one embodiment the blind is made from fully opaque material and acts as a blackout by preventing the passage of light through the sheet. The blind may comprise a single thickness of the sheet material, or multiple thicknesses in order to achieve the required degree of opacity. References to “sheet material” in the following should be construed as including either a single thickness or multiple thicknesses of material. 
         [0008]    The elongate element or elements may be flexible and/or elastic. 
         [0009]    Preferably the flexible sheet is rectangular in form, with rounded corners. However, other shapes such as circular, trapezoidal or triangular may be used. Where polygonal shapes are used, the corners may be radiussed. 
         [0010]    The fixing arrangement may include a suction cup device for fixing to a window pane, or may comprise a hook or a loop adapted to engage a handle of a casement window. In one embodiment, the fixing device may comprise an enlargement at the end of a tension element, the enlargement adapted to be placed outside the window and the tension element adapted to pass between a casement or sash and a fixed part of the window frame when the window is closed. 
         [0011]    In a further embodiment, the fixing device may be attached to a window or a window frame by means of an adhesive pad. 
         [0012]    The window blind may be provided with one fixing device attached at a central position on the flexible sheet. Alternatively or additionally, a plurality of fixing devices may be provided at locations spaced around the perimeter of the flexible sheet or spaced inwardly from the edge of the sheet. 
         [0013]    The frame may comprise a resilient flexible hoop extending round the edge of the sheet. The resilient hoop may be formed of spring metal, or of resilient plastics material optionally reinforced with fibre. The hoop may be circular or rectangular in cross-section. The hoop may be received within a circumferentially-extending hem formed at the edge of the sheet. Alternatively, the frame may comprise two or more elongate members extending between corners of a polygonal blind and adapted to impart tension to the blind sheet material. The elongate members may extend diagonally or diametrally of the blind sheet. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Embodiments of the invention will now be described in detail with reference to the accompanying drawings, in which: 
           [0015]      FIG. 1  is a perspective view of the deployed window blind, seen from the side which faces into the room in use; 
           [0016]      FIG. 2  is a view similar to  FIG. 1 , showing the “outside” face of the blind; 
           [0017]      FIG. 3  is a sectional view of the window blind of  FIGS. 1 and 2 , on the line III-III in  FIG. 2 ; 
           [0018]      FIG. 4  is a vertical sectional view of the window blind deployed on a window; 
           [0019]      FIG. 5  shows an alternative embodiment of the window blind, provided with two fixing devices; 
           [0020]      FIG. 6  is a detailed review, to an enlarged scale, of a corner region of the window blind of 
           [0021]      FIG. 5 ; and 
           [0022]      FIG. 7  is a view similar to  FIG. 4 , showing an attachment device for attaching the blind to a bay window, or a window with deep reveals. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    Referring now to the drawings,  FIGS. 1 to 3  show a window blind B comprising a sheet  1  of light-impermeable blackout material which is flexible to enable the blind B to be folded for storage and transport. In alternative embodiments, the sheet  1  may permit a part of the incident light to pass through, to produce a low level illumination in the room. 
         [0024]    The blind B is of generally rectangular shape, with rounded corners. Extending round of the perimeter of the sheet  1  is a resilient flexible hoop  2  which extends within a hem sewn at the edge of the sheet  1 . 
         [0025]    The centre of the sheet  1  is formed with an opening  3 , through which a flexible cord  4  extends. The opening  3  closely surrounds the cord  4  so as to minimise light leakage, but the cord  4  may be freely drawn through the opening  3  for adjustment of the effective length of the cord, as will be described below. 
         [0026]    As can be seen in  FIG. 2 , a suction cup  5  is attached to one end of the cord  4 , on the side of the sheet  1  which will face towards the window, in use. At the other end of the cord  4  is positioned an enlarged stopper  6 , and between the stopper  6  and the sheet  1  is an adjusting clamp  7 . The adjusting clamp may be slid along the cord  4 , and a fixed at a selected position along the length of the cord. The adjusting clamp  7  is so dimensioned that it will not pass through the opening  3 . The stopper  6  is so dimensioned that the clamp  7  cannot be moved past the stopper, and thus the clamp  7  is captive. The cord  4 , clamp  7  and suction cup  5  together form the fixing device for securing the blind to a window. 
         [0027]    An alternative fixing arrangement is illustrated in  FIG. 1 . In the alternative fixing arrangement, the opening  3   a  in the sheet material  1  is slot-like, to allow a strap  4   a  to pass freely through the opening  3   a.  To one end of the strap  4   a  is attached a suction cup  5   a,  and the strap  4   a  is formed with a series of buttonholes  7   a  along its length. A button  7   b  is sewn onto the sheet material  1 , and can engage in a selected one of the buttonholes  7   a  to immobilise the strap  4   a  relative to the sheet material in a selected position, thus setting the effective length of the strap  4   a  which extends between the opening  3   a  and the suction cup  5   a.    
         [0028]    The flexible nature of the sheet  1  and the resilient hoop  2  enable the blind B to be folded for storage and transport to approximately one quarter of its full area. The blind is folded by grasping two opposite edges, and a rotating them in opposite directions so as to form the hoop  2  into a  FIG. 8 . The two loops of the  FIG. 8  can then be brought together, to form a generally circular flat package. Due to the resilience of the hoop  2 , when the flat package is released it will spring open and return to the deployed condition shown in  FIGS. 1 and 2 . The blind may be retained in the folded condition by means of tabs attached to the sheet adjacent its circumference, and releaseably attachable to the sheet at a point on the circumference which is adjacent the tab when the blind is folded. Alternatively, the blind may be retained in the folded condition by placing it within a close-fitting container or case. 
         [0029]    A principal application for the blind of the present invention is for use in darkening a room, such as a hotel room, when taking children on holiday. The blind is transported to the holiday destination in its folded condition within the user&#39;s luggage, and the dimensions of the blind (when folded) may be determined by typical dimensions of a suitcase or other travelling bag. 
         [0030]    On arrival at the destination, the blind is unfolded into the deployed condition seen in  FIGS. 1 and 2 . The clamp  7  is released, and moved so as to be adjacent to the stopper  6 , and the cord  4  is drawn through the sheet  1  so that the maximum effective length of cord  4  is available between the suction cup  5  and the sheet  1 . The suction cup  5  is then attached to the window pane at a position such that the upper edge of the blind B is positioned adjacent the wall above the window. The cord  4  is then drawn through the sheet  1  so as to reduce the effective length of the cord  4  and bring the hoop  2  of the blind into contact with the wall on each side of the window and possibly also below the window. The clamp  7  is then slid along the cord towards the opening  3 , and clamped in position adjacent the opening  3  when the cord is tight to secure the blind B. 
         [0031]    If the blind is insufficiently large to cover the entire extent of the window, a second blind may then be fitted in the manner described above, to cover the remaining area. Two or more blinds may be fitted side-by-side, or one above the other, as required to cover the window area. The weight of each blind is supported by its cord, which extends downwardly and inwardly (relative to the room) from the suction cup attached to the window pane. Alternatively, an extension panel (not shown) may be attached either permanently or releasably to one edge of the blind, the extension panel preferably being of opaque flexible sheet material and hanging down from the blind in use to obscure an area below the blind. 
         [0032]      FIG. 4  is a sectional view showing the blind in place at a window within a cavity wall. The cavity wall comprises an inner leaf  10  and an outer leaf  11 , the window frame  12  and window pane  13  being mounted in the outer leaf. It will be appreciated that the window pane  13  is set back from the surface of the wall within the room. A window board  14  forms a sill beneath the window, and extends into the room slightly beyond the inner leaf  10 . With this arrangement, the blind B is arranged with the lower edge of the hoop  2  supported on the window board  14 , the suction cup  5  attached to the window pane  13 , and the cord  4  extending generally horizontally from the suction cup since the weight of the blind is supported on the window board  14 . The depth between the window pane  13  and the surface of the wall within the room is spanned at least partly by the section of cord  4  extending between the suction cup  5  and the opening  3 , the clamp  7  providing adjustment to cope with different depths of inset of the window pane  13  from the inside surface of the wall. 
         [0033]      FIGS. 5 and 6  illustrate a second embodiment of the window blind,  FIG. 6  showing the clamp  7  in more detail. As can be seen in  FIG. 5 , the blind is provided with two fixing devices, each comprising a cord  4  passing through an opening  3  in the sheet material  1  of the blind. In this embodiment, the openings  3  are not positioned centrally in the sheet  1 , but positioned adjacent respective corners of the blind. Further fixing devices may be additionally provided, for example adjacent the lower (as seen in the Figure) corners of the blind, or adjacent the mid-regions of the edges of the blind.  FIG. 6  shows in detail the structure of the edge of the blind, where the sheet material  1  extends around the flexible hoop  2  and is then sewn together by one or more lines of stitching  15  to form a hem which contains the hoop  2 . In the illustrated embodiment, the hoop is circular in cross-section. It is however foreseen that the hoop  2  may be formed from spring metal strip or other resilient material of rectangular-cross-section. 
         [0034]    The clamp  7  is shown in cross-section in  FIG. 6 . The clamp comprises an outer casing  20  within which a plunger  21  is movable. The plunger  21  is urged outwardly of the casing  20  by a spring  22 . The casing and plunger are formed with a through-bore  23 , through which the cord  4  can pass. Under the action of the spring  22 , the plunger  21  is moved so as to misalign the section of the through-bore in the plunger from the sections of the through-bore in the casing  20 , clamping the cord  4  and preventing the housing  20  from moving along the cord. By depressing the plunger  21  to bring the three sections of the through-bore  23  into alignment, the clamping action is removed and the casing  20  may be freely movable along the cord  4 . The end of the cord may be knotted or provided with a stopper element  6  to retain the clamp  7  captive. The cord  4  extends through an opening  3  in the sheet material  1  of the blind, and a suction cup  5  is attached to the end of the cord for attaching the cord to the window. Alternative or additional attaching means may be provided, such as a hook  24  or a loop  25  to engage a window handle, or an adhesive pad which can be fixed to a window or wall surface and detached from the cord  4  after use. In a further alternative, the cord  4  may be replaced by a strap or ribbon, and may be additionally or alternatively an elastic element to enable tension to be maintained in the cord even if the clamp  7  should slip. 
         [0035]    In any of the above embodiments, the opening  3  may be bounded by a wear-resisting eyelet of plastics or metal. In a particularly low-cost embodiment, the clamp  7  may be omitted and the cord  4  simply knotted at the eyelet  3 . In a further even more economic or embodiment, the cord  4  may be replaced by a tension element of flexible material fixed at one end to the sheet  1  and at the other end to the suction cup  5 . Adjustment of the distance between the suction cup  5  and the sheet  1  may be provided by making the tension element from an elastic material. 
         [0036]    In a further embodiment (not shown) the clamp  7  may be omitted, and the cord  4  may be provided at the stopper end with a fastener attachable to the sheet material of the blind at a number of locations spaced by differing distances from the opening  3 . By adjusting the spacing of the stopper end of the cord from the opening  3 , the length of cord between the opening and the suction cup  5  may be adjusted. The stopper end of the cord may be attached to the sheet material of the blind by any suitable means, such as by a burr-type hook-and-loop fastener, or by a tab having a buttonhole engaging one of a number of buttons sewn on to the sheet material. 
         [0037]    In a yet further embodiment, the tension element or cord  4  may be replaced by a rod extending from the fixing device to the sheet material of the blind. The rod may be telescopically adjustable in length. 
         [0038]    Adjustment of the length of the tension element joining the fixing device to the sheet material may alternatively be provided by fixing one end of the tension element to the sheet material, and providing an adjustable cleat at the fixing device. In such an embodiment, the fixing device (such as suction cup  5 ) will be fixed to the window, and a free end of the tension element hanging down from the cleat of the fixing device would then be pulled to draw the sheet material of the blind towards the fixing device and thus set the blind into position. 
         [0039]      FIG. 7  illustrates an arrangement for fixing the blind to a window deeply set into a wall, using the same reference numerals for like parts. 
         [0040]    Legislation in some countries may limit the total length of the cord  4 , such that the fixing device  5  cannot be spaced far enough from the blind  1  to reach the window pane  13  if the window has deep reveals. In such circumstances, an extension piece  26  may be used. The extension piece comprises an elongate rod-like body  26  with a fixing device such as a suction cup  27  at one end, and a fixture such as a hook  28 , loop, karabiner or other structure at its other end. The fixture  28  is constructed so that as the cord  4  is tensioned, the suction cup  5  at the end of cord  4  is drawn up to the fixture  28 , but does not pass it. In the embodiment illustrated, the fixture  28  is a hook which can be releaseably hooked round the cord  4 . 
         [0041]    To deploy the blind in a deeply inset window, the suction cup  27  of the extension piece is attached to the window so that the rod  26  projects into the room. The blind is unfolded an the cord  4  is engaged with the hook  28  at a point near the suction cup  5  of the blind. The blind  1  is then positioned to cover the window, and the cord  4  drawn through the blind into the room until the suction cup  5  is pulled against the fixture  28  and the cord  4  is in tension sufficient to support the blind. The stopper  7  is then adjusted to maintain tension in the cord, as described previously. 
         [0042]    In another embodiment (not illustrated), the extension piece may be permanently engaged with the cord  4 , and may hang down between the blind and the window when not in use.