Abstract:
The present invention comprises various combinations of 2″×4″, 2″×6″, 2″×8″, 2″×10″ and 2″×12″ members stacked on top of one another with one longitudinal edge of each member co-aligned. In this configuration, the non-aligned longitudinal edges form shallow steps which act as a ramp, allowing wheeled implements to easily transition form ground level to the floor level of the portable building.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention generally relates to portable buildings and, more particularly, to a level transition device for portable buildings. 
     BACKGROUND OF THE INVENTION 
     Portable buildings, such as small garden sheds or yard barns, are popular means for providing an enclosed storage area or workspace near one&#39;s home. Typically, the portable building is either constructed on-site or constructed off-site and transported to the site where the building is to be used. In either case, the building is typically constructed so that it simply rests upon a relatively flat piece of ground, with no masonry foundation. Not only does this reduce cost, but it allows for easy movement of the building to another location in the future. 
     One drawback of the lack of a finished foundation is that the floor threshold at the entrance to the portable building is raised significantly above the level of the surrounding ground, typically about eight (8) inches. While this height differential is not significant for persons walking into and out of the portable building, it does represent a significant obstacle to rolling implements, such as lawn mowers, wheelbarrows and hand trucks. 
     There is therefore a need to a device that will allow for rolling implements to easily ingress and egress to and from a portable building. The present invention is directed toward meeting this need. 
     SUMMARY OF THE INVENTION 
     The present invention comprises various combinations of 2″×4″, 2″×6″, 2″×8″, 2″×10″ and 2″×12″ members stacked on top of one another with one longitudinal edge of each member co-aligned. In this configuration, the non-aligned longitudinal edges form shallow steps which act as a ramp, allowing wheeled implements to easily transition from ground level to the floor level of the portable building. 
     In one form of the invention a level transition device for a portable building is disclosed, the level transition device comprising a first board having cross-section dimensions of approximately 2″×4″ and cut to a predetermined length; a second board having cross-sectional dimensions of approximately 2″×6″ and cut to the predetermined length; a third board having cross-sectional dimensions of approximately 2″×10″ and cut to the predetermined length; a fourth board having cross-sectional dimensions of approximately 2″×12″ and cut to the predetermined length wherein the first, second, third and fourth boards are stacked such that a longitudinal edge of each of said boards are substantially co-aligned; a first hole drilled through the first, second, third and fourth boards; a second hole drilled through the first, second, third and fourth boards; a first bolt disposed through the first hole; a first nut secured to the first bolt; a second bolt disposed through the second hole; and a second nut secured to the second bolt whereby the first, second, third and fourth boards are held securely together. 
     In another form of the invention, a portable building is disclosed comprising an enclosure; an opening in the enclosure; a sill disposed in the opening; a level transition device coupled to the sill, the level transition device comprising a first board having cross-section dimensions of approximately 2″×4″ and cut to a predetermined length; a second board having cross-sectional dimensions of approximately 2″×6″ and cut to the predetermined length; a third board having cross-sectional dimensions of approximately 2″×10″ and cut to the predetermined length; a fourth board having cross-sectional dimensions of approximately 2″×12″ and cut to the predetermined length wherein the first, second, third and fourth boards are stacked such that a longitudinal edge of each of said boards are substantially co-aligned; a first hole drilled through the first, second, third and fourth boards; a second hole drilled through the first, second, third and fourth boards; a first bolt disposed through the first hole; a first nut secured to the first bolt; a second bolt disposed through the second hole; and a second nut secured to the second bolt whereby the first, second, third and fourth boards are held securely together. 
     In yet another form of the invention, a level transition device for a portable building is disclosed, the level transition device comprising a first board having cross-section dimensions of approximately 2″×4″ and cut to a predetermined length; a second board having cross-sectional dimensions of approximately 2″×8″ and cut to the predetermined length; a third board having cross-sectional dimensions of approximately 2″×12″ and cut to the predetermined length; wherein the first, second, and third boards are stacked such that a longitudinal edge of each of said boards are substantially co-aligned; a first hole drilled through the first, second, and third boards; a second hole drilled through the first, second, and third boards; a first bolt disposed through the first hole; a first nut secured to the first bolt; a second bolt disposed through the second hole; and a second nut secured to the second bolt; whereby the first, second, and third boards are held securely together. 
     In another form of the invention, a portable building is disclosed comprising an enclosure; an opening in the enclosure; a sill disposed in the opening; a level transition device coupled to the sill, the level transition device comprising a first board having cross-section dimensions of approximately 2″×4″ and cut to a predetermined length; a second board having cross-sectional dimensions of approximately 2″×8″ and cut to the predetermined length; a third board having cross-sectional dimensions of approximately 2″×12″ and cut to the predetermined length; wherein the first, second, and third boards are stacked such that a longitudinal edge of each of said boards are substantially co-aligned; a first hole drilled through the first, second, and third boards; a second hole drilled through the first, second, and third boards; a first bolt disposed through the first hole; a first nut secured to the first bolt; a second bolt disposed through the second hole; and a second nut secured to the second bolt; whereby the first, second, and third boards are held securely together. 
     In another form of the invention, a level transition device for a portable building, the level transition device comprising a first board having cross-section dimensions of approximately 2″×4″ and cut to a predetermined length; a second board having cross-sectional dimensions of approximately 2″×6″ and cut to the predetermined length; a third board having cross-sectional dimensions of approximately 2″×8″ and cut to the predetermined length; a fourth board having cross-sectional dimensions of approximately 2″×10″ and cut to the predetermined length; a fifth board having cross-section dimensions of approximately 2″×12″ and cut to the predetermined length; wherein the first, second, third, fourth and fifth boards are stacked such that a longitudinal edge of each of said boards are substantially co-aligned; a first hole drilled through the first, second, third, fourth and fifth boards; a second hole drilled through the first, second, third, fourth and fifth boards; a first bolt disposed through the first hole; a first nut secured to the first bolt; a second bolt disposed through the second hole; and a second nut secured to the second bolt; whereby the first, second, third, fourth, and fifth boards are held securely together. 
     In yet another form of the invention, a portable building is disclosed comprising an enclosure; an opening in the enclosure; a sill disposed in the opening; a level transition device coupled to the sill, the level transition device comprising a first board having cross-section dimensions of approximately 2″×4″ and cut to a predetermined length; a second board having cross-sectional dimensions of approximately 2″×6″ and cut to the predetermined length; a third board having cross-sectional dimensions of approximately 2″×8″ and cut to the predetermined length; a fourth board having cross-sectional dimensions of approximately 2″×10″ and cut to the predetermined length; a fifth board having cross-sectional dimensions of approximately 2″×12″ and cut to the predetermined length; wherein the first, second, third, fourth and fifth boards are stacked such that a longitudinal edge of each of said boards are substantially co-aligned; a first hole drilled through the first, second, third, fourth and fifth boards; a second hole drilled through the first, second, third, fourth and fifth boards; a first bolt disposed through the first hole; a first nut secured to the first bolt; a second bolt disposed through the second hole; and a second nut secured to the second bolt; whereby the first, second, third, fourth and fifth boards are held securely together. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of a preferred embodiment level transition device of the present invention. 
     FIG. 2 is a perspective view of the preferred embodiment level transition device of FIG. 1, installed on a portable building. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, and alterations and modifications in the illustrated device, and further applications of the principles of the invention as illustrated therein are herein contemplated as would normally occur to one skilled in the art to which the invention relates. 
     With reference to FIG. 1, a preferred embodiment level transition device of the present invention is illustrated and indicated generally at  10 . The level transition device  10  is comprised of four lengths of board stock (preferably treated wood) cut to a length substantially equal to the width of the door opening of the portable building to which it will be attached (typically four (4) feet). 
     A first board  12  is preferably formed from 2″×12″ board stock. A board  14  rests upon board  12  and is preferably cut from 2″×10″ board stock. A board  16  rests upon the board  14  and is preferably cut from 2″×6″ board stock. Finally, a board  18  rests upon the board  16  and is preferably cut from 2″×4″ board stock. All of the boards  12 - 18  are preferably cut to the same width (substantially corresponding to the width of the door opening). It will be appreciated by those having ordinary skill in the art that the dimensions given above are approximate and refer to standard dimensional labels given to the board stock, even though the finished dimensions of the board stock are typically slightly less than the quoted dimensions. 
     As can be seen from reference to FIG. 2, stacking the boards  12 - 18  results in a series of small steps  20 , which will behave as a discontinuous ramp when a wheel having a diameter of approximately four inches or greater is rolled up or down the steps  20 . This is because the two-inch rise of each step within the steps  20  is not a significant rise when compared to the diameter of the wheel. 
     As can also be seen from FIG. 2, the boards  12 - 18  are aligned with one another along one longitudinal edge  22  thereof. A hole  24  is then drilled through all of the boards  12 - 18  and a carriage bolt  26  is passed therethrough and secured with a nut  28 . In a preferred embodiment, the hole  24  is countersunk on both ends such that the head of the carriage bolt  26  and the nut  28  lie substantially flush with the surface of the level transition device  10 . Carriage bolts  26  are preferably secured near either end of the level transition device  10 , and additional carriage bolts  26  may be placed intermediate thereto, depending upon the width of the level transition device  10 . In a preferred embodiment, the carriage bolts  26  and the nut  28  are galvanized. 
     With reference to FIG. 2, the level transition device  10  is illustrated when installed at the opening of a portable building. As can be seen, the level transition device  10  provides for a relatively smooth transition between a ground level  30  and the sill  32  of the door opening. In a preferred embodiment, the level transition device  10  is secured to the portable building doorsill  32  by means of a pair of lag bolts  34  which are extended through holes  36  drilled transversely through the board  18 . The lag bolts  34  may then be screwed into the door opening sill  32  in order to securely attach the level transition device  10  to the portable building. In a preferred embodiment, the lag bolts  34  are placed near opposite ends of the level transition device  10  and are preferably galvanized. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. For example, the preferred embodiment disclosed herein may be modified to accommodate various height transitions. For example, an approximately six inch (6″) height transition may use 2″×4″, 2″×8″ and 2″×12″ pieces of stacked board stock. Similarly, a ten inch (10″) height transition may use 2″×4″, 2″×6″, 2″×8″, 2″×10″ and 2″×12″ pieces of stacked board stock.