Abstract:
An adjustable self-centering trolley for suspending a horizontally sliding door such as a shower door from an overhead track.

Description:
RELATED APPLICATIONS  
       [0001]     This specification hereby incorporates by reference and claims priority of U.S. provisional patent application Ser. No. 60/721,520, Martin inventor, filed Sep. 27, 2005 and entitled Self-Centering Trolley for Horizontally Sliding Doors. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates to horizontally sliding doors and more particularly to horizontally sliding shower doors.  
       BACKGROUND OF THE INVENTION  
       [0003]     Horizontally sliding doors are typically carried along a track in an overhead bracket. The door is hung from one or more trolleys having rollers or wheels that run along an overhead track.  
         [0004]     Many of these doors of the prior art sometimes bind in the overhead track through torsional forces, causing the door to be difficult to move. For example if the wheels are not originally installed to distribute weight on both wheels equally, or twist during use, they are off-centered with an unequal load on the two wheels of the trolley. The wheels may then bind or move with more difficulty when the door is moved because the leading wheel on each trolley bears a greater load than the trailing wheel. Two trolleys are typically used on a door or window and if one or both of them do not hang evenly from the track then moving the door may be difficult.  
         [0005]     What is needed then is a self-centering door trolley that will dynamically center itself in response to use.  
       SUMMARY OF THE INVENTION  
       [0006]     A solution to the above has been devised. A trolley for supporting a door or window from a track in an overhead bracket is disclosed, the trolley comprises an elongate member having two rollers affixed on one end that are adapted to move in an overhead bracket track. At the other end of the member is a pivot that affixes to the door being carried by the trolley, the door is pivotally affixed to the pivot. The trolley member can be formed from two plates joined together and the pivot is affixed to and sandwiched between the two plates. In the preferred embodiment the pivot further includes a bushing made of elastic material such as neoprene. When the wheels are placed in the track to suspend the door, the trolley will rotate about the pivot and orient itself in the track and relative to the door to automatically more evenly distribute the weight of the door between the two rollers resting in the track.  
         [0007]     At the end of the trolley member distal the pivot, flanges or arms can be extended at an angle to the length of the member and each flange or arm adapted to be affixed to a roller at a plurality of points, so that a user can adjust the distance between the door and the rollers by selecting a point of attachment for each roller prior to installing the door on the track. In the preferred embodiment each flange or arm has a plurality of voids formed in the flange or arm to be coupled with a roller by an axle inserted in a void and the roller.  
         [0008]     The trolley can be used in a system including an overhead bracket having a track adapted to support the rollers of the trolley. In the preferred embodiment the overhead bracket is of a generally concave U-shape and the track is on the inside of the bracket. Alternatively, the track might be formed on an exterior of a side of the bracket or even the top of the bracket. In any of these embodiments more than one track and trolley system can be included in a bracket, a plurality of tracks, and each track supports a door or window and the track is oriented on the bracket to allow the doors to move or slide past relative each other. In a typical shower door application for example two tracks will be formed on the interior of the bracket, and two doors will slide past each other to allow access to the shower.  
         [0009]     In a method of the present invention, one or more trolleys are pivotally affixed to a door and the rollers or wheels are placed in a track formed in the overhead bracket. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a side view of the trolley of the present invention adjacent a track shown in an end view of an overhead bracket.  
         [0011]      FIG. 2  is a front view of the trolley of the present invention.  
         [0012]      FIG. 3  is a schematic side view of trolleys of the present invention and end view of an overhead bracket.  
         [0013]      FIG. 4  is a schematic side view of joined plates forming the trolley of the present invention, without rollers affixed.  
         [0014]      FIG. 5  is a schematic front view of the trolley of the present invention, without rollers affixed.  
         [0015]      FIG. 6  is a back view of the door trolley of the present invention.  
         [0016]      FIG. 7  is a side view of the door trolley of the present invention.  
         [0017]      FIG. 8  is a side view of the trolley of the present invention resting in the track of an overhead bracket.  
         [0018]      FIG. 9  is a perspective view of the trolley of the present invention resting in the track of an overhead bracket.  
         [0019]      FIG. 10A  is a schematic side view of another embodiment of the present invention, with an embodiment of an overhead bracket.  
         [0020]      FIG. 10B  is a schematic side view of yet another embodiment of the present invention, with yet another embodiment of an overhead bracket. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     The following description, and the figures to which it refers, are provided for the purpose of describing examples and specific embodiments of the invention only and are not intended to exhaustively describe all possible examples and-embodiments of the invention.  
         [0022]     Referring now to  FIGS. 1-5  a trolley  11  having a plurality of wheels or rollers  13 A and  13 B is provided that is attached to a door  15  on a pivot  17 , to allow the trolley to move rotationally about the pivot point (as indicated by arrow). A bushing  19  preferably made from an elastic material such as neoprene is provided on the pivot pin  17  to facilitate rotation. The rollers  13 A and  13 B of the trolley  11  are placed in a groove or track  21  in an overhead bracket  23 , whereby the door  15  is suspended from the overhead bracket  23 . This rotational movement allows the wheels  13 A,  13 B of the trolley  11  to distribute the weight of the door equally on each wheel on a track or groove  23 , making the trolley self-centering.  
         [0023]     In the preferred embodiment of the trolley  11  of the present invention is used with a door  15  made of a pane of plastic or glass as a shower enclosure door. Two rollers  13 A and  13 B are used on the trolley  11  and the bushing  19  is made of neoprene. The door is suspended from a track or groove  21  formed inside a U-shaped overhead bracket  23 . Two doors  15  are installed in overhead bracket  23 , that may slide over one another, as shown in  FIG. 3 .  
         [0024]     Alternatively, the rollers could be suspended from a groove or track  34  formed outside of the overhead bracket  23 , as shown in  FIG. 10A  or even ride along the top of an overhead bracket itself  36  as shown in  FIG. 10B .  
         [0025]     In the preferred embodiment of the trolley  11  of the present invention is made of joined first plate  30  and second plate  32  having flanges or arms  25 A and  25 B extending laterally at an upward angle. Voids  27 A and  27 B are formed in the flanges to receive axles  29 A and  29 B holding rollers  13 A and  13 B respectively. In this construction a user can therefore select a pair of voids  27 A and  27 B to fix wheels  13 A and  13 B to, to adjust the distance of the door from the track when installing the door. First plate  30  is affixed to pivot pin  17  at one end and second plate  32  is formed to be attached to and support the pivot at its opposite end. Alternatively the trolley  11  could be formed from a single piece of rigid material such as metal or plastic.  
         [0026]     It will be appreciated that the invention has been described hereabove with reference to certain examples or preferred embodiments as shown in the drawings. Various additions, deletions, changes and alterations may be made to the above-described embodiments and examples without departing from the intended spirit and scope of this invention.