Abstract:
A system and method for preventing vertical blinds from tangling is disclosed. The system and method comprise the location of apertures at the vertical centers of rotation of the vertical vanes used in the blinds. A long thin member, such as a flexible cord, a flexible ribbon, or a rigid rod, is then placed through the apertures in a horizontal orientation and fixed on both ends. This prevents the vanes from overlapping one another in a manner that would cause entanglement.

Description:
BACKGROUND 
       [0001]    This disclosure relates to coverings for windows and doors and more specifically to vertical blinds used to shade the interior of a residence or commercial building. 
         [0002]    Most vertical blinds hang freely from a head rail using clips at the top of each vane located at the center of vertical rotation of the vanes. The horizontal spacing and rotation of the clips about a vertical axis of rotation is controlled by a mechanism in the head rail that in turn is controlled by cords, rods, or motors responsive to sensors and/or operated by a user. 
         [0003]    The vanes are generally free to swing about their points of attachment to the head rail in axes perpendicular to the vertical axis of rotation. In some cases there are untensioned cords connecting the vanes together near the bottoms of the vanes that limit the distance the vanes can swing, but many modern vertical blinds don&#39;t have these, meaning that the vanes have only a single point of attachment. Whether these untensioned cords are present or not, the vanes can easily swing individually in the wind or in response to users touching them. The vanes are often made of a flexible material, which allows them to bend and twist as well. As a result, external disturbances often causes the vanes to overlap in a configuration that does not allow the horizontal spacing between the clips holding the vanes be reduced when the blinds are opened. Careless users may then ignore the misaligned vanes and try to open the blinds by pulling too hard on the opening/closing cords or rod that control the spacing between the vanes to try to overcome the resistance created by overlapping vanes. These high forces to try clear jammed vanes can result in permanent damage to the system—or costly repairs. The frequency of damage and the high cost of repairs has caused vertical blinds not to be used in many situations where they would be optimal for shading a room while still allowing maximum visibility to the outdoors. 
       SUMMARY 
       [0004]    In one embodiment a system and method for preventing vertical blinds from tangling is disclosed. The system and method use an over-rotation prevention element that runs horizontally through openings in the vanes of a vertical blind system in a manner that prevents the vanes from having a total rotation about a vertical axis greater than approximately 180 degrees and/or prevents overlapping of the vanes in a way that impedes the opening of the blinds. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The present disclosure is described in conjunction with the appended figures in which: 
           [0006]      FIG. 1  shows prior art vertical blinds mounted in front of a sliding glass door; 
           [0007]      FIG. 2  shows the blinds of  FIG. 1  with an over-rotation prevention element mounted through openings in each vane; 
           [0008]      FIG. 3  shows the blinds of  FIG. 1  or  FIG. 2  with a valence mounted over the head rail and over-rotation prevention element; 
           [0009]      FIGS. 4   a  to  4   h  show how the vanes of typical prior art vertical blinds get tangled and show how an embodiment of the present invention can mitigate this issue; 
           [0010]      FIG. 5  shows a perspective view of an over-rotation prevention element mounted in a set of vanes; 
           [0011]      FIG. 6   a ,  FIGS. 6   b , and  6   c  show configurations for openings in vanes suitable for use with an over-rotation prevention element; and 
           [0012]      FIGS. 7   a  and  7   b  show examples of geometries for over-rotation prevention elements. 
       
    
    
       [0013]    To assist in the understanding of one embodiment of the present invention, the following list of components or features and associated numbering found in the drawings is provided herein: 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
               
                   
                 Number 
                 Component or Feature 
               
               
                   
                   
               
             
             
               
                   
                 100 
                 Vertical blinds mounted in front of a sliding glass door 
               
               
                   
                 101 
                 Vane 
               
               
                   
                 101a 
                 Vane rotated 90 degrees clockwise 
               
               
                   
                 101b 
                 Vane rotated 45 degrees counter-clockwise 
               
               
                   
                 101w 
                 Disrupted vane 
               
               
                   
                 101x 
                 Disrupted vane 
               
               
                   
                 101y 
                 Disrupted vane 
               
               
                   
                 102 
                 Head rail 
               
               
                   
                 103 
                 Vane rotation adjustment rod 
               
               
                   
                 104 
                 Opener/closer cord 
               
               
                   
                 105 
                 Valence 
               
               
                   
                 106 
                 Vane attachment element (or clip) 
               
               
                   
                 200 
                 Improved system 
               
               
                   
                 201 
                 Over-rotation prevention element 
               
               
                   
                 201a 
                 Over-rotation prevention element having a flat profile 
               
               
                   
                 202 
                 Attachment element 
               
               
                   
                 203 
                 Opening 
               
               
                   
                 203a 
                 Keyhole notch opening 
               
               
                   
                 203b 
                 Shared opening 
               
               
                   
                 204c 
                 Elliptical opening 
               
               
                   
                   
               
             
          
         
       
     
         [0014]    It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood that the invention is not necessarily limited to the particular embodiments illustrated herein. 
       DETAILED DESCRIPTION 
       [0015]    The ensuing description provides preferred exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description of the preferred exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing a preferred exemplary embodiment. It should be understood that various changes could be made in the function and arrangement of elements without departing from the spirit and scope as set forth in the appended claims. 
         [0016]    Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, shapes and geometries may be shown generically and details may be left out in order not to obscure the embodiments in unnecessary detail. 
         [0017]      FIG. 1  shows typical prior art vertical blinds at  100 . The blinds  100  have vertical vanes  101  connected to a horizontally mounted head rail  102 , using vane attachment elements (clips)  106  that secure the vanes  101  to the head rail  102  at a point near the top of each vane  101 . The vane attachment elements  106  allow the vanes  101  to hang freely, meaning that the vanes  101  are able to swing about axes perpendicular to their vertical axes of rotation (i.e. pivot about a horizontal plane) at a point near the tops of the vanes  101 . The vanes  101  typically have a constant thickness and have a center of gravity located at their centers, which means that the vane attachment elements  106  are typically located at the centers of the tops of the vanes  101  in order for the vanes  101  to hang straight vertically. The vane attachment elements  106  typically connect securely to the vanes  101  by means of a hole in each vane  101  through which a part of the attachment element  106  is placed (i.e. clipped into). 
         [0018]    Further referring to  FIG. 1 , the headrail  102  typically has a mechanism capable of moving the vane attachment elements  106  horizontally in a longitudinal direction in the headrail  102  using an opener/closer cord  104  hanging from one end of the head rail  102  to open or close the blinds wherein opening the blinds means moving the vane attachment elements  106  closer to one another to one or both ends of the head rail and closing the blinds means distributing the vane attachment elements longitudinally on the underside of the head rail. In some cases a motor instead of an opener/closer cord  104  moves the vanes. A second actuator, shown as a vane rotation adjustment rod  103 , is used to rotate the vanes  101  in unison about their individual vertical axes of rotations to change the viewing angle through the vanes  101  or to move the vanes  101  to a position that blocks view completely. In some cases, a motor is used an actuator for rotating the vanes  101  instead of the vane rotation adjustment rod shown at  103 . 
         [0019]    By looking at  FIG. 1 , one can understand that the individually rotatable vanes are in a horizontally aligned row—meaning that centers of the tops of the vanes are all in a straight horizontal line. Since the vertical centers of rotation of the vanes intersect the centers of the tops of the vanes, the lines defining the vertical centers of rotation of the vanes are all in the same vertical plane. One can also see that each of the vanes of the system shown in  FIG. 1  has a single attachment point, at its top. There are also vertical blinds that have multiple attachment points, one example of which is vertical blinds that have untensioned cords connecting the vanes together near the bottoms of the vanes that limit the distance the vanes can swing. 
         [0020]      FIG. 2  shows an improved system  200  that incorporates an over-rotation prevention element, shown at  201 , which goes through openings in the vanes  101  and prevents the vanes from rotating to a position that causes overlap. The over-rotation prevention element  201  is secured at both ends by attachment elements  202 . The attachment elements  202  in the embodiment shown are located underneath and near the ends of the head rail. The attachment elements  202  may be secured to the head rail, the attachment elements  202  may be secured to a wall, or the attachment elements  202  may be secured to any other fixed points. The attachment elements  202  may be rigid or flexible. With the exceptions of the over-rotation prevention element  201 , the attachment elements  202 , and the openings in the vertical blinds (not shown), the improved system  200  is identical to the vertical blinds  100  shown in  FIG. 1 . 
         [0021]      FIG. 3  shows the vertical blinds of  FIG. 1  or  FIG. 2  with a valence  105  that hides the vane attachment elements,  106  in  FIG. 1 , and head rail  102  in  FIG. 1 . The valence  105  can also hide the over-rotation prevention element  201  and attachment elements  202  shown in  FIG. 2 . 
         [0022]      FIG. 4   a  to  4   h  illustrate the principle of operation of an embodiment of the present invention.  FIG. 4   a  shows Section A-A of  FIG. 1  in which the vanes  101  are spaced apart and rotated about a vertical axis to a straight visibility position that allows one to look straight through a window or sliding glass door. Phantom lines show what happens when the vanes  101  are rotated. Note that the rotation is about a vertical axis at a point close to the center of the vanes and that the allowed rotation of the vanes is approximately 90 degrees in each direction from the straight visibility position giving a total rotation of approximately 180 degrees from a point at which an end of a vane touches an adjacent vane to its right (as shown at  101   a ) to the point at which that same end of the vane touches an adjacent vane to its right (approximately 45 degrees of rotation beyond the position shown at  101   b ).  FIG. 4   b  shows the same vanes  101  of  FIG. 4   a  when the blinds are opened (i.e. centers of rotation moved together and to one side of the window or sliding glass door to be covered).  FIGS. 4   c  and  4   d  show the vanes of  FIG. 4   a  and  FIG. 4   b  in positions that do not allow a user to see through a window or sliding glass door. In  FIGS. 4   a  to  4   d  there is no tangling of the vanes and it is easy to open and close the blinds as one moves them from the position shown in  FIG. 4   a  to the position shown in  FIG. 4   b  or from the position shown in  FIG. 4   c  to the position shown in  FIG. 4   d.    
         [0023]      FIG. 4   e  shows vanes at  101   w ,  101   x , and  101   y  that have been disrupted from their natural rotational limitations relative to one another, i.e. over-rotated. Over-rotation can be described as vanes that have been rotated past one another (overlapped) or have been rotated more than the natural 180 degrees of rotation for each vane  101  in a set of vertical blinds. Specifically over-rotation is illustrated in  FIG. 4   e  by the following examples: (a) the same side of vane  101   w  is touching two adjacent vanes ( 101  and  101   x ) on opposite edges, (b) vane  101   x  is touching vane  101   w  on a side opposite of what a vane operating in its natural 180 degrees of rotation would touch a vane to its left (i.e. it has overlapped the vane to its left), (c) vane  101   x  is touching vane  101   y  on a side opposite of what a vane operating in its natural 180 degrees of rotation would touch a vane to its right (i.e. it has overlapped the vane to its right), and (d) the same side of vane  101   y  is touching an adjacent vane to its left on a side opposite of what would be natural. Disruptions of the types exhibited by vanes  101   w ,  101   x , and  101   y  in  FIG. 4   g  can be caused by wind or by a person sticking their hands through the blinds.  FIG. 4   f  shows what occurs when one tries to slide the vanes  101  together when there is a disrupted vane  101   x —the blinds cannot be opened. If one tries to use force, something bends or breaks, creating damage. 
         [0024]      FIGS. 4   g  and  4   h  show section BB in  FIG. 2  and illustrate an embodiment of the present invention—an over-rotation prevention element  201 . The over-rotation prevention element  201  goes through an opening in each vane and prevents the vanes from rotating beyond a point where they will jam as was illustrated in  FIG. 4   f . Instead, the vanes  101  stay in proper orientation relative to one another, the vanes  101  cannot rotate more their natural 180 degrees of rotation, the vanes  101  cannot overlap, and the vertical blinds can be opened (i.e. centers of the vanes moved adjacent to each other) as illustrated in  FIG. 4   h.    
         [0025]      FIG. 5  provides an isometric view of the key elements of one embodiment of the present invention;  FIG. 6   a ,  FIG. 6   b , and  FIG. 6   c  show alternate embodiments of openings for an over-rotation prevention element  201 ; and  FIG. 7   a  and  FIG. 7   b  show alternate embodiments of the cross-sectional geometry of over-rotation prevention elements.  FIG. 5  shows four vanes  101  hanging from clips  106 . The over-rotation prevention element  201  is shown as a cord that is mounted to an attachment element  202 . If the entire system were to be shown, there would be another attachment element  202  at the right side of the set of vanes  101 . The over-rotation prevention element  201  goes through an opening  203  in each vane at approximately the vertical centers of rotation of the vertical vanes  101 . In the embodiment shown, the openings  203  and over-rotation prevention element  201  are also located close to the clips  106  and near the tops of the vertical vanes  101 . The openings in  FIG. 5  are shown as round holes.  FIG. 6   a ,  FIG. 6   b , and  FIG. 6   c  show alternate embodiments of the openings such as a keyhole notch  203   a , an opening that is part of the clip attachment hole  203   b , and an elongated hole  203   c . Referring to  FIG. 6   b , the opening  203   b  does not necessarily need to be below the vane attachment element  106 , the opening  203   b  could also comprise an opening in the vane attachment element, thereby being integrated into the head rail attachment element. The over-rotation prevention element  201  in the embodiment shown in  FIG. 5  is a tensioned round cord having a relatively small cross-sectional area. As shown by  FIG. 6   a , the over-rotation prevention element  201  can also be defined as having a cross-sectional width and height that is substantially less than its horizontal length in a direction parallel with the head rail (shown in  FIG. 2 ). As shown by  FIG. 7   b , the over-rotation prevention element does not necessarily need to have a round cross sectional profile. The embodiment of the over-rotation prevention element  201   a  shown in  FIG. 7   b  is a flat tape, strip, or ribbon that has a vertical dimension (i.e. height) that is much greater than its thickness. It is possible to fabricate an over-rotation prevention element  201  or  201   a  from a rigid material. It is also possible to fabricate an over-rotation prevention element  201  or  201   a  from a larger diameter flexible non-tensioned material. The specifics of the materials, cross-sectional size, cross-sectional shape, and rigidity of the over-rotation prevention element can be of any form or material capable of being understood by anyone skilled in the art. 
         [0026]    Further referring to  FIG. 5 , the attachment element  202  shown connects to the over-rotation prevention element by means of a hole in the attachment element  202 . This connection can be made in any form capable of being understood by anyone skilled in the art. There can be benefit to having an attachment means that provides and maintains tension if a flexible cord is to be used as the over-rotation prevention element. The attachment element  202  and over-rotation prevention element  201  can also be a single unit. The attachment element  202  can be secured to the head rail ( 102  in  FIG. 2 ), to a wall, or to any other fixed location. 
         [0027]    A number of variations and modifications of the disclosed embodiments can also be used. The principles described here can also be used for in applications other than vertical blinds. While the principles of the disclosure have been described above in connection with specific apparatuses and methods, it is to be clearly understood that this description is made only by way of example and not as limitation on the scope of the disclosure.