Abstract:
A mechanism directed to the art of rolling ladders is provided. A swivel roller capable of being attached to a rolling ladder to enable the rolling ladder to traverse an interior corner. The swivel roller has a mounting bracket with a hinged member and first and second wheels for supporting and moving the rolling ladder along a rail.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of co-pending U.S. Provisional Patent Application Ser. No. 61/791,710, filed on 15 Mar. 2013, and titled “Ladder Corner Roller.” 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Rolling ladders, such as ladders which roll along a fixed rail, are well known to those in the art. Rolling ladders are generally used in shelving situations in which the uppermost shelves are out of reach. Step ladders are not ideal as their A-frame design prohibits the ladder from being placed close enough to the shelf for the user to reach the shelf contents, and if turned sideways, the user is required to rotate the body to reach the shelves, putting strain on the back, hips, and knees. Additionally, extension ladders are not ideal, as they must rest against the shelf, which could cause damage to the shelving or the objects being stored on the shelving. Moreover, placement of the ladder may be inconsistent and unstable. Therefore, rolling ladders provide a stable, easily movable, ladder which provides both aesthetic and functional value. 
         [0003]    However, rolling ladders are generally hindered by their inability to travel through corners. Due to the way rolling ladders are attached to a rail, by rollers near the top of each leg, the radius of the rail in a corner must be fairly large to prevent binding of the rollers on the rail. A large rail radius bend in a corner means that the rail will be a fairly large distance away from the shelving, thus reducing the benefits gained by using a rolling ladder as a user will have to extend away from the ladder to reach items stored on the shelves in a corner. Accordingly, the art of rolling ladders could benefit from a rolling ladder capable of traversing smaller radius corners. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention relates to a roller assembly for a rolling ladder, more particularly a swivel roller capable of traversing corners. The swivel roller comprising a mounting bracket with a hinged member attached to the rolling ladder and a pair of wheels attached to the hinged member positioned to be on opposite sides of a rail. It is contemplated that the present invention allows the ladder to traverse a rail having a significantly smaller radius corner than other rollers, thereby permitting the ladder to remain closer to the shelving. 
         [0005]    One aspect of the invention provides a swivel roller for interfacing a rolling ladder with a rail, the swivel roller having an attachment bracket attached to the ladder, a hinged mounting bracket connected to the attachment bracket, and a wheel attached to the hinged mounting bracket. 
         [0006]    The ladder may have length and the hinged mounting bracket may have a pivot axis substantially parallel with the length of the ladder and the wheel may have a rotation axis substantially perpendicular to the hinged mounting bracket pivot axis. 
         [0007]    The hinged mounting bracket may be slidably connected to the attachment bracket. 
         [0008]    The wheel may have a wheel first end portion, a wheel second end portion opposite the wheel first end portion, and a wheel valley between the wheel first end portion and the wheel second end portion, whereby the wheel first end portion is closer to the hinged mounting bracket member than the wheel second end portion, and wherein the wheel valley has an inwardly curved profile to receive the rail within. 
         [0009]    The wheel first end portion may have a wheel first end portion diameter and the wheel second end portion may have a wheel second end portion diameter, wherein the wheel first end portion diameter is larger than the wheel second end portion diameter. 
         [0010]    Another aspect of the invention provides a swivel roller for interfacing a rolling ladder having a length to a rail, the swivel roller having an attachment bracket attached to the rolling ladder, a hinged mounting bracket comprising a mating member rotatably affixed to a hinged member, wherein the mating member is slidably attached to the attachment bracket for linear movement of the ladder relative to the hinged mounting bracket, a first wheel having a first wheel axis of rotation, a second wheel having a second wheel axis of rotation, the first wheel and the second wheel attached to the hinged member, wherein the first wheel is next to the second wheel, with the first wheel axis of rotation and the second wheel axis of rotation are substantially perpendicular to the length of the ladder, and whereby the first wheel may be configured to be placed substantially above the rail and the second wheel may be configured to be placed substantially below the rail. 
         [0011]    The first wheel may have a first wheel first end portion, a first wheel second end portion opposite the first wheel first end portion, and a first wheel valley between the first wheel first end portion and the first wheel second end portion, and the second wheel may have a second wheel first end portion a second wheel second end portion opposite the second wheel first end portion, and a second wheel valley between the second wheel first end portion and the second wheel second end portion, whereby the first wheel first end portion is closer to the hinged member than the first wheel second end portion, whereby the second wheel first end portion is closer to the hinged member than the second wheel second end portion, wherein the first wheel valley has an inwardly curved profile to receive the rail within, and wherein the second wheel valley has an inwardly curved profile to receive the rail within. 
         [0012]    The first wheel first end portion may have a first wheel first end portion diameter, the first wheel second end portion may have a first wheel second end portion diameter, the second wheel first end portion may have a second wheel first end portion diameter, and the second wheel second end portion may have a second wheel second end portion diameter, and whereby the first end portion diameter of at least one of the first wheel first end portion and second wheel first end portion is larger than the respective second end portion diameter of the first wheel second end portion or second wheel second end portion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a perspective view of a rolling ladder incorporating swivel rollers according to the present invention. 
           [0014]      FIG. 2  is a perspective view of one of the swivel rollers of  FIG. 1 . 
           [0015]      FIG. 3  is a side view of the swivel roller of  FIG. 1 . 
           [0016]      FIG. 4  is a top view of the swivel roller of  FIG. 1 . 
           [0017]      FIGS. 5A-7B  illustrate a rolling ladder incorporating the swivel rollers in use on a rail. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0018]    Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention. Further, it should be known that any reference to a top or a bottom in this disclosure is for illustrative purposes only and should not be construed as limiting the spatial orientation of the present invention. 
         [0019]      FIG. 1  illustrates rollers  10 A and  10 B according to the present invention. Swivel rollers  10 A and  10 B are substantially identical in form but individually designated for ease of describing the swivel rollers  10 A and  10 B in use. However, part number “10” will be used when describing the components of an individual swivel roller  10 . As shown here, the rollers  10 A and  10 B are attached to a rolling ladder  72  and installed on a rail  74  attached to a shelving system  76 . In addition to the rollers  10 A and  10 B positioned at the top of the ladder, bottom rollers  78  may be attached to the bottom of the ladder to assist in rolling the ladder  72 . 
         [0020]      FIGS. 2-4  show an enlarged view of a swivel roller  10  attached to the ladder  72  and positioned on the rail  74 . The roller  10  comprises an attachment bracket  20  and a mounting bracket  30 . 
         [0021]    With particular attention to  FIG. 4 , the attachment bracket  20  may be seen. The attachment bracket  20  comprises a first side member  22  adjacent to an interface side member  24 , and a second side member  26  also adjacent to the interface side member  24  and opposite the first side member  22 . The interface side member  24  preferably extends past the first side member  22  and the second side member  26  thereby providing extensions  28 . 
         [0022]    The mounting bracket  30  comprises a mating member  32 , a hinged member  40  rotatably attached to the mating member  32 , and a first wheel  50  and a second wheel  60  both attached to the hinged member  40 . 
         [0023]    The mating member  32  shown here comprises a receiving portion  34  and mating member knuckles  36  having mating member knuckle holes  38  (see  FIG. 3 ) located longitudinally therethrough. The receiving portion  34  is configured to receive the extensions  28  of the attachment bracket  20  in a sliding relationship. 
         [0024]    The hinged member  40  comprises hinge member knuckles  42  and a face  46  opposite the hinge member knuckles  42 . The face  46  provides a place to attach the first wheel  50  and the second wheel  60  with wheel pins or screws  68 . Additionally, the hinge member knuckles  42  have hinge member knuckle holes  44  located longitudinally therethrough (see  FIG. 3 ). The hinge member knuckles  42  interface with the mating member knuckles  36  and are joined by a hinge pin or screws  70  placed through the respective knuckle holes  38  and  44 , thereby allowing the hinged member  40  to pivot relative to the mating member  32  in the directions illustrated by arrow A in  FIG. 4 . Thus, the hinged member  40  preferably has a rotational axis substantially parallel with the length of the ladder  72  and substantially perpendicular with rotational axis of the first and second wheels  50  and  60 . 
         [0025]    The first wheel  50  comprises a first wheel first end portion  52 , a first wheel valley  54 , and a first wheel second end portion  56 . The first wheel valley  54  preferably has an inwardly curved profile substantially similar to the curved circumferential surface profile of the rail  74 . The first wheel first end portion  52  has a larger diameter than the diameter of the first wheel second end portion  56 , and, as shown here, the first wheel first end portion  52  is closest to the hinged member face  46 . 
         [0026]    The second wheel  60  comprises a second wheel first end portion  62 , a second wheel valley  64 , and a second wheel second end portion  66 . The second wheel valley  64  preferably has an inwardly curved profile substantially similar to the curved circumferential surface profile of the rail  74 . The second wheel first end portion  62  has a larger diameter than diameter of the second wheel second end portion  66 , and, as shown here, the second wheel first end portion  62  is positioned closest to the hinged member face  46 . 
         [0027]    The substantially similar profiles of the rail  74  and the first and second wheel valleys  54  and  64  encourages consistent alignment of the first and second wheels  50  and  60  on the rail  74  and discourages the hinged member  40  from rotating relative to the mating member  32  at any time other than when traversing a corner (shown in  FIGS. 6A-6B ). 
         [0028]    The substantially circumferential interface between the roller  10  and the rail  74  permits the ladder  72  to rotate radially about the rail  74 . This capability in combination with the slidable interface between the mounting bracket  30  and the attachment bracket  20  permits the ladder  72  to be placed in a position in which the ladder  72  is substantially vertical and parallel to the shelving system  76 , yet also permits the ladder  72  to be rotated away from the shelving system  76  to provide a more user-friendly climbing angle. The ladder  72  and attachment bracket  20  may also be completely separated from the mounting bracket  30 . 
         [0029]      FIGS. 5A-7B  demonstrate how the rollers  10 A and  10 B move along the rail  74  and the interior corner IC in the direction of arrow B. With attention to  FIGS. 5A and 5B , the ladder  72  is shown moving along rail  74  towards the interior corner IC. Roller  10 A is forward with respect to roller  10 B in direction A and both rollers  10 A and  10 B are parallel 
         [0030]    As the ladder  72  moves along the rail  74  through the interior corner IC as shown in  FIGS. 6A and 6B , the rollers  10 A and  10 B rotate with respect to the ladder  72  to permit the ladder to traverse the interior corner IC. 
         [0031]      FIGS. 7A and 7B  illustrate the ladder  72  exiting the interior curve IC. The swivel rollers  10 A and  10 B return to their parallel orientation. 
         [0032]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention.