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RELATED APPLICATIONS 
     This application is based on, and claims priority from U.S. Provisional Patent Application Ser. No. 60/276,971, filed Mar. 18, 2001, the disclosure of which is incorporated herein by this reference. 
    
    
     TECHNICAL FIELD 
     This invention is directed to the field of portable stairs. More particularly, the invention is directed to improved stairs for use with mobile construction trailers and modular or pre-fab building structures, such as are commonly utilized on construction projects. 
     BACKGROUND 
     Various platforms have long been utilized for placing adjacent exit and entry ports, normally conventional doors, found in construction trailers and other similar portable structures. A wide variety of such structures have been known and utilized as appropriate for various applications. And, although most such stairs and accompanying platforms have historically been constructed with fixed, non-adjustable platform heights, a few alternate structures have been developed which, in some limited fashion or another, enable the user to accommodate or provide some adjustment in the platform height. 
     However, a common problem encountered in locating such structures which are known to me is that, when operating on uneven ground, such structures are often not uniformly adjusted (often are not even variably adjustable) to provide a level platform. Thus, those structures inevitably leave a gap of a few inches between the required or desirable platform height, and the actual platform height. Additionally, a certain amount of tilt often occurs if the stair and platform combination is not carefully set up or assembled, as the case may be. Also, it is often rather difficult to achieve a quick adjustment of the available adjustable designs, so, workmen often found to be simply too lazy or too pressed for time to properly make available adjustments. Often, the result is a job-site trailer with an entrance/exit stairs/platform which does not comply with applicable regulatory requirements, such as the Occupational Safety and Health Act (OSHA), or equivalent state acts, when the projects are in the United States. 
     Thus, there remains a continuing unmet need for a combination stairs/platform for portable structures which are adjustable in height, and which, even though the platform height is adjustable, can utilize a single stair design, and wherein both the stairs and the platform are fully compliant with applicable regulatory standards. 
     SOME OF THE OBJECTS, ADVANTAGES, AND NOVEL FEATURES 
     Accordingly, one objective of my invention is to provide a design for portable stairs which have an adjustable platform height. 
     Another objective of my invention is to provide a design for portable stairs in which the platform height is adjustable while the same set of stairs is utilized. 
     Another important objective is to provide a platform structure which is rapidly adjustable in height, yet retains the high strength necessary to support the design load with adequate safety factor. 
     A related and important objective is to provide a structure in which the platform legs are quickly adjustable, yet of high strength. 
     Another important objective is to provide a structure and design in a portable stair unit in which the stairs may be conventionally installed, yet can be installed in different heights attached to the same platform, rather than having the requirement for a new set of stairs when the platform height is adjusted. 
     Finally, another important objective is to provide a high strength portable stair structure which can be conveniently and easily built with conventional manufacturing processes, so that manufacturing costs are minimized. 
     BRIEF SUMMARY 
     I have now invented a portable platform and stairs for portable office buildings, where the platform is of adjustable height. This is important since it enables the platform to be reused at different sites, although uneven ground, or building setups of differing heights, is encountered. 
     My portable stair system has four major components. These components are a platform, a stair assembly, a stair handrail, and a platform handrail. 
     Importantly, my novel platform has individually adjustable legs, preferably at least four in number. I prefer to use a slidably adjustable mechanism that is securable with friction fit fasteners at any desired length, preferably from more than zero up to at least as much as fourteen inches in height. In this manner, the platform can be adjusted to fit any of the various portable office building types currently available. 
     Moreover, my platform stair system needs no extra bolts for assembly, and resultantly, it is one of the easiest to assemble stair systems available. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In order to enable the reader to attain a more complete appreciation of the invention, and of the novel features and the advantages thereof, attention is directed to the following detailed description when considered in connection with the accompanying drawings, wherein: 
     FIG. 1 is a partially exploded perspective view of my novel portable stair system for portable office buildings, showing the major parts and pieces, including the platform unit with (i) individually adjustable legs, and (ii) upper and lower stair unit receiving mounts, the stair assembly with a pair of individually adjustable feet and a pair of platform attachment pocket pins for mounting the stair assembly to either the upper or to the lower stair receiving mounts on the structural framework of the main platform, a stair handrail frame, and a platform unit hand rail frame. 
     FIG. 2 is a partially exploded perspective view of my portable stair system, showing the stair assembly in a position for attachment to the upper stair unit receiving mounts on the structural framework of the platform unit, with one adjustable stair leg shown affixed to the stairs, and one adjustable stair leg removed from the stairs to reveal threads for adjustment, and with the platform legs extended downwardly. 
     FIG. 3 is perspective view of the structural framework below the deck of a platform unit, and also showing, at the upper end of the vertical support leg members, receivers adapted to receiving the lower ends of columns of the main platform hand rail frame and the main platform end rail hand rail frame, and also showing the pivotally mounted main platform end rail frame. 
     FIG. 4 is a side pictorial view of my portable stair system as first illustrated in FIG. 1, but now showing the stair assembly mounted to the upper stair receiving mounts of the structural framework for the main platform unit, and with the adjustable stair leg at a first extended length, and with one of the platform legs fully retracted, but with another platform vertical support leg member partially retracted, so as to provide level support of main platform unit over uneven ground. 
     FIG. 5 is a side pictorial view of my portable stair system as first illustrated in FIG. 4, but now showing the stair assembly mounted to the lower stair receiving mounts of the structural framework for the main platform unit, and with the adjustable stair leg at a second, retracted length, and with one of the platform legs fully extended, retracted, but with another platform vertical support leg member almost fully extended, so as to provide level support of main platform unit over uneven ground. 
     FIG. 6 shows in detail a vertical support leg member that supports the main platform unit, showing how a C-shaped portion in the lower member is adapted for adjustably nesting in an upper tubular member, and also showing a bolt and caged nut for securing the foot of the lower member at a selected height H below the lower end of the upper tubular member, so as to position the main platform unit in a level condition at a preselected distance above a substrate(e.g., earth or parking lot). 
     FIG. 7 shows, in cross-sectional view, one embodiment for a slidable sleeve and J-latch for connecting the stair hand rail frame to the main platform unit hand rail frame. 
     FIG. 8 shows the strength of the structural support framework to support the platform unit, where a test is in progress to support an automobile from the structural support framework. 
     FIG. 9 shows, in cross-sectional view, the nesting of a C-shaped lower support member in an upper tubular member, as well as a caged nut, with external washer and bolt for securing the upper tubular member to the lower support member at a desired position. 
    
    
     The foregoing figures, being exemplary, contain various elements that may be present or omitted from actual implementations depending upon the circumstances. An attempt has been made to draw the figures in a way that illustrates at least those elements that are significant for an understanding of the various embodiments and aspects of the invention. However, various other elements of the platform and stairs system are also shown and briefly described to enable the reader to understand how various optional features may be utilized in order to provide a useful platform and stair system that is easily changed from various heights and to both left hand and right hand rail configurations. 
     DETAILED DESCRIPTION 
     Attention is directed to FIG. 1, where a perspective view of my portable platform stair system is illustrated. The system includes an adjustable platform unit  10  and stairs  12 . At least one platform unit  10  is provided, having preselected dimensions and having a plurality of side portions, here, with a rectangular deck  14 , side portions  16 ,  18 ,  20 , and  22  are provided. Below the deck  14 , a structural support framework  24  is provided to support the deck  14  of the platform unit  10 . The structural support framework  24  has plurality of substantially vertical support leg members  30 . Each of the vertical support leg members  30  has a vertically displaceable slide portion or lower member  32 . Each of the slide portion lower members  32  has a foot  34  that is securable at a desired length L with respect to a lower end  36  of an upper tubular member  38  of the vertical support leg members  30 . For example, a first lower member  32   1 , has a foot  34   1  that is securable at a length L 1  with respect to lower end  36   1  of upper tubular support member  38   1 . Likewise, a second lower member  32   2  has a foot  34   2  that is securable at a length L 2  with respect to lower end  36   2  of a second upper tubular support member  38   2 . Thus, as in the embodiment illustrated, where four vertical support leg members  30  are provided, then a third lower member  32   3  has a foot  34   3  that is securable at a length L 3  with respect to lower end  36   3  of a third upper tubular support member  38   3 , and a fourth vertical support leg member  30   4  has a fourth lower member  32   4  having a foot  34   4  that is securable at a length L 4  with respect to lower end  36   4  of a fourth upper tubular support member  38   4 . 
     Along at least one of the plurality of side portions  16 ,  18 ,  20 , and  22  at least one upper stair receiving member  40   1  and at least one lower stair receiving member  42   1 , are affixed to a portion of said structural support framework  24 . As illustrated in FIG. 1, a pair of upper stair receiving members (or “pockets”)  40   1  and  40   2  are provided. Likewise, as illustrated in FIG. 1, a pair of lower stair receiving members (or “pockets”)  42   1 , and  42   2  are provided. 
     To provide access to the deck  14  of the main platform unit  10 , at least one stair unit  12  is provided. The stair unit has a predetermined length L S , and is connectable with each of the upper stair receiving members  40   1  and  40   2  or alternately, with the lower stair receiving members  42   1 , and  42   2 , for secure, stable attachment at a desired height. As seen by comparison of FIGS. 4 and 5, the stairs  12  can be provided secured in a first position wherein a first stair member  48   1  is substantially even, heightwise, with the level of the deck  14 . Alternately, the stairs  12  can be secured in a second position wherein a first stair member  48   1 , is located below deck  14  by a height substantially equal to H s , the height between first  48   1  and second  48   2  stair members. In the embodiment illustrated herein, four stairs, specifically first stair member  48   1 , second stair member  48   2 , third stair member  48   3 , and fourth stair member  48   4  are provided. 
     A pair of opposing side panels  50  and  52  is provided for the stair unit  12 . The stair unit has an upper end  54 , at which is located at least one platform attachment member  56 . In the embodiment illustrated, a pair of platform attachment members  56   1 , and  56   2 , each of which is sized and shaped for attachment to each of the upper stair receiving members  40   1  and  40   2  or alternately, to each of the lower stair receiving members  42   1  and  42   2 , for secure, stable attachment of stairs  12  to platform unit  10  at a desired height H P  above a substrate G such as the earth or a parking lot (see FIG.  5 ). Note that height H P  may vary, below different portions of the deck  14 , due to an uneven or non-level substrate G. As more easily seen in FIG. 2, attachment members  56   1  and  56   2  provide a cylindrical shape of outer diameter D 56  complementary to inner diameter D 40  of tubular cylindrical upper stair receiving members  40   1  and  40   2  or alternately, with inner diameter D 42  of tubular cylindrical lower stair receiving members  42   1  and  42   2 . 
     The stair unit  12  also has a lower end  60 , at which a first adjustable foot  62  having a ground engaging pad  64  is located, and at which a second adjustable foot  66  having a second ground engaging pad  68  is located. The first  62  and second  66  adjustable feet are independently vertically adjustable for securement of ground engaging pads and  68  at desired distances D 1  and D 2 , respectively, below the lower end  60  of stair unit  12 , thus supporting the lower end  60  of stair unit  12  at a desired distance H S  above a selected substrate therebelow (see FIGS.  3  and  4 ). As noted in FIGS. 4 and 5, the distances D 1  and D 2  may have a first instance and a second instance (for example D 2  (1) and D 2  (2)) of varying height. As illustrated in the embodiment shown in FIGS. 1 and 2, the first  62  and second  66  adjustable feet are extensible and threadably adjustable via use of threaded shaft  67  acting with threaded foot receiver  69  to move feet  62  and  66  along a vertical axis. 
     As noted above, a plurality of steps  48  are positioned between said upper end  54  and the lower end  60  and between the pair of opposing side panels  50  and  52 . 
     Importantly, the at least one stair unit  12  is adapted for attachment to the at least one platform unit  10  at the at least one upper stair receiving member  40   1  (and  40   2  as applicable), or alternatively, at the at least one lower stair receiving member  42   1  (and  42   2  as applicable), so as to enable utilization of the stairs  12  at a first selected height H s  above a selected substrate G 1 , and, by repositioning the stair unit  12 , at a second selected height H s  of the main platform unit  10  above a selected substrate G 2 . 
     Turning now to FIGS. 6 and 9, a better view can be seen of one of the substantially vertical support leg members  30 , which is made up of an upper tubular member  38  and a lower support member  32 . The lower support member  32  is slidingly nested in the upper tubular member  38 . The upper tubular member  38  and the lower support member  32  are adapted for moving with respect each to the other along a common vertical axis. The upper tubular member  38  and the lower support member  32  are fixable in axial relationship so as to support the platform deck  14  at a selected vertical distance H P  above a selected substrate G. In one embodiment, the lower support member  32  is provided as a generally C-shaped tubular member having a vertically running channel  80  defined by edge walls  82  and  84  of the C-shaped tubular member of a selected length. A nut  88  is located within the generally C-shaped tubular lower support member  32 . A bolt  90 , and a washer  92 , are provided for affixing bolt  90  to nut  88 . A bolt hole  94  defined by edge wall  96  is provided in the lower reaches  98  of the upper tubular member  38 . The bolt hole  94  is aligned with the vertically running channel  80  in the lower support member  32 , and is adapted to receive bolt  90  therethrough for securement with the nut  88 . In the embodiment illustrated in FIGS. 6 and 9, the nut  88  is caged by the generally C-shaped tubular lower support member  32 . The vertically running channel  82  in the lower support member  32  provides a slot for passage of the bolt  90  when the lower support member  32  is adjusted upwardly to nest in the upper tubular member  38 , or when lower support member  32  is otherwise extensibly adjusted. As shown in FIG. 6, to facilitate the use of a caged nut, the nut  38  may be provided in a generally square configuration, so that the nut  88  is easily caged within the generally C-shaped tubular member  32 . Although mentioned above, FIG. 6 also provides a view of the foot or foot plate  34 , which is sized and shaped for transmitting a portion of a load from the platform unit to a substrate below, with a preselected force loading on said substrate, so that the platform unit is supported by the substrate G. 
     Returning now to FIG. 2, in one embodiment, the at least one upper stair receiving member  40  comprises at least two upper step mounting brackets  40   1  and  40   2 . Two of the at least two upper step mounting brackets  40   1  and  40   2  are spaced apart along a longitudinal axis to opposite sides of one side portion (here, side  22 ) of the platform unit  10  in a matched, spaced relationship to the platform attachment members  56   1  and  56   2  on stair unit  12 . In one embodiment illustrated, a pair of upper step mounting brackets  40   1  and  40   2  is provided. Likewise, the at least one lower stair receiving member  42  comprises at least two lower step mounting brackets  42   1  and  42   2 . Two of the at least two lower step mounting brackets  42   1  and  42   2  are spaced apart along a longitudinal axis to opposite sides of one side portion (here, side  22 ) of the platform unit  10  in a matched, spaced relationship to the platform attachment members  56   1  and  56   2  on stair unit  12 . In one embodiment illustrated, a pair of lower step mounting brackets  42   1  and  42   2  is provided. In one embodiment, each of the at least one upper stair receiving members is provided in the form of a tubular member welded to one of said substantially vertical support leg members  30 . In similar fashion, in one embodiment each one of the at least one lower stair receiving members is provided in the form of a tubular member welded to one of said substantially vertical support leg members  30 . 
     The apparatus illustrated in FIGS. 1,  2 ,  4 , and  5  utilizes a configuration wherein the at least one platform attachment member  56  at the upper end of the at least one stair  12  includes at least two pocket pins, and more specifically a pair of pins  56   1  and  56   2 , which are each sized and shaped for close fitting mating engagement within one of the at least two upper step mounting brackets  40   1  and  40   2 . Likewise, the at least one platform attachment member  56  at the upper end of the at least one stair  12  includes at least two pocket pins, and more specifically a pair of pins  56   1  and  56   2 , which are each sized and shaped for close fitting mating engagement within one of the at least two lower step mounting brackets  42   1  and  42   2 . 
     Turning now to FIGS. 1 and 3, it should be noted that each of the vertical support leg members  30  have, at the upper end  100  thereof, a receiver  102 . A main platform unit hand rail side frame  110  is provided. The main platform unit hand rail side frame  110  has a pair of vertically oriented main platform rail column members  112  and  114 , and running therebetween, an upper horizontal rail  116 , and a central horizontal rail  118 . Each of the vertically oriented main platform rail column members  112  and  114  have a lower end  120 , and, spaced upward from lower end  120 , a stop  122 . Each of the vertically oriented main platform rail column members  112  and  114  are sized and shaped for placement downwardly into a receiver  102  until stop  122  is reached, so that a vertically standing, secure main platform unit hand rail side frame  110  is provided. 
     Additionally, a unique, interchangeable main platform end hand rail frame  130  is provided. The main platform unit end frame  130  has a vertically oriented main platform end hand rail column member  132 , and a vertically oriented main platform end hand rail partial column member  134 , and running therebetween, an upper horizontal end rail  136  and a central horizontal end rail  138 . The vertically oriented main platform end rail column member  132  has a lower end  140 , spaced upward from the lower end  140 , a stop  142 . The vertically oriented main platform end rail column member  132  is sized and shaped for placement downwardly into a receiver  102  until stop  142  is reached. 
     Importantly, the main platform end hand rail partial column member  134  is secured to, for pivotal movement with respect to, one of the main platform rail column members,  112  or  114 , so that a vertically standing, secure main platform unit hand rail side frame is provided. In this manner, the same main platform end hand rail frame unit  130  is usable whether on the right hand side (when oriented facing rising stairs), or on the left hand side (when oriented facing rising stairs) of platform unit  10 . One configuration useful for providing such a pivotally connected apparatus as just described is shown in FIG. 3, where the main platform end hand rail frame  130  is pivotally secured to a vertical oriented main platform rail column member (here, column  114 ) via a sleeve  150 . In this configuration, the vertically oriented main platform rail column member  114  is a cylindrical tubular member having an outer diameter D 114 , and the sleeve  150  is sized and shaped larger than (with inner diameter D 150 ), but complementary to and designed for close fitting engagement with, the outer diameter D 114  of the vertically oriented main platform rail column member  114 . The sleeve  150  is securely affixed to the main platform end hand rail partial column member  114 , and thus securely affixes the main platform unit hand rail side frame  110  with the main platform unit end rail frame  130 . As shown in FIGS. 1,  3 ,  4 , and  5 , the sleeve  150  is vertically affixed to the main platform end hand rail partial column member  114 . As noted in FIG. 3, the main platform end hand rail frame  130  is free to pivot by at least an angle alpha of 180°, so that the main platform side rail frame  110  can be utilized either on the left hand or on the right hand side of the main platform unit  10 . 
     For safety, the stair unit  12  is provided with a step hand rail frame  160 . The step hand rail frame  160  has an upper column member  162 . The upper column member  162  has an upper end  164 , a middle portion  166 , and a lower end  168 . Spaced upwardly from the lower end  168  is a stop  170 . The step hand rail frame  160  also has a lower column member  172 . The lower column member  172  has an upper end  174 , and lower end  176 . Spaced upwardly from the lower end  176  is a stop  178 . A horizontally oriented generally V-shaped rail member  180  is provided, and, in one embodiment, as an integral part of step hand rail frame  170 . The horizontally oriented generally V-shaped rail member  180  has an apex end  182 , a first leg  184 , and a second leg  186 . The first leg  184  is oriented generally horizontally and has an outer end  188  affixed to the middle portion  166  of the upper column member  162 . The second leg  186  has an outer end  190  affixed to the upper end  164  of the upper column member  162 . Near the apex end  182 , the horizontally oriented generally V-shaped rail member  180  is affixed to the upper end  174  of the lower column member  172 . 
     To secure the stair rail frame unit  130  to the stairs  12 , lower ends  168  and  176  of upper column member  162  and lower column member  172 , respectively, are inserted into either the left hand or right hand set of upper stair rail receiving pockets  190  and lower stair rail receiving pockets  192 . 
     To secure the stair rail frame unit  130  to the main platform unit hand rail frame  110 , a hook  200  is displaceably affixed (such as via hook sleeve  202  that is slidable over upper column member  172 , see FIG. 7) to the upper column member  172  between the upper end  164  and the middle portion  166 . The hook  200 , as shown, may be provided in a generally J-shaped configuration sized and shaped for secure, linking engagement with one of the vertical oriented main platform rail column members (here, column  112 ) so as to secure the step hand rail frame  130  to the main platform unit hand rail frame  110 . 
     In one embodiment, as generally illustrated herein, the main platform unit  10  comprises a deck  14  portion generally rectangular in planar shape, but this disclosure should not be considered so limited, as the teachings provided herein may be utilized in many desired shapes for a deck  14 . Also, it is generally desirable, but not absolutely necessary, that deck  14  be provided with a slip resistant surfacing such as the diamond plate design  206  shown in FIG.  2 . Likewise, generally desirable, but not absolutely necessary, that steps  48   1 ,  48   2 ,  48   3 , and  48   4 , etc., of stairs  12  be provided with a slip resistant surfacing such as the diamond plate design  208  shown in FIG.  2 . 
     For strength, various additional features are desirable. First it is often desirable, and depending on step plate thickness, perhaps necessary, that some or all of the steps  48   1 ,  48   2 ,  48   3 , and  48   4 , etc., of stairs  12  be provided with a vertically oriented, longitudinally running stiffener portion  210  extending between said opposing side panels  50  and  52 . Also, a stiffening lip  212  is desirable on each of the steps  48   1 ,  48   2 ,  48   3 , and  48   4 , etc. Next, the structural support framework  24  to support the platform unit  10  includes, in one embodiment, a plurality of upper perimeter tubular frame members or upper braces  230 . The plurality of upper perimeter tubular frame members  230  include upper tubular frame members  230  running between, and affixed to, each one of the plurality of substantially vertical support leg members  30 . Where, as shown in FIG. 3, the platform unit  10  and deck  14  are rectangular, each one of the vertical support leg members  30  may be positioned at a corner of the rectangular platform unit  10 . 
     As seen in FIG. 3, in one embodiment, the platform unit  10  apparatus has a structural support framework  24  that further includes a plurality of floor beam members  234 . The floor beam members  234  are affixed to, and run between, two of the plurality of upper perimeter tubular frame members  230 . 
     Also, the structural support framework  24  desirably further includes a plurality of intermediate perimeter tubular frame members  240 . The plurality of intermediate perimeter tubular frame members or center braces  240  desirably include intermediate tubular frame members  240  running between, and affixed to, each one of the plurality of substantially vertical support leg members  30 . The overall-strength provided by the design just described for platform unit  10  can be further appreciated by reference to FIG. 8, which illustrates the platform unit  10  supporting an automobile  300 . 
     In summary, the portable stair system described herein is simple to assembly and install. The platform stair handrail needs no additional bolts or other hardware to assemble, and thus it will be one of the most readily installed systems available. As illustrated, the portable stair system mounts in two different positions. An upper or high position makes the first step a part of the platform deck. A lower position adds one more step. Also, the stair assembly has adjustment legs. As illustrated, the adjustment legs of the stair assembly are adjustable from a height of about 2 inches above the ground to as much as about 8 inches from the ground. In conjunction with adjustment of the vertical legs  30 , an adjustment in height of deck  14  from about 26 inches to about 40 inches from the substrate G is easily accomplished. 
     The platform handrail is unique in that it incorporates a swivel hinge, making it possible to be installed on either the right side or on the left side of the deck  14 . As illustrated, the step rail must be mounted first, and the hook fastener will slide up and down on the step rail vertical column. Then, the platform rail is installed, which using the hook described herein, locks the steps and rail in place, making it possible to slide together, without the need for bolts, pins, or clips. 
     Importantly, the portable platform stair system is manufactured of strong, yet lightweight materials. Normally, a strong steel frame is provided to meet the anticipated loads. However, it is to be understood that other materials of construction can be utilized, such as structural composites, etc., and advantageously utilize the adjustable step structures described herein. 
     It is to be appreciated that my portable stair system for portable office buildings is an appreciable improvement in the art of portable stairs. My novel design addresses the problem of how to provide for differing building height, as well as for uneven ground, while minimizing the labor requirement for installation and for removal, to provide a significantly portable stair system. Although only a few exemplary embodiments have been described in detail, various details are sufficiently set forth in the drawings and in the specification provided herein to enable one of ordinary skill in the art to make and use the invention(s), which need not be further described by additional writing in this detailed description. It will be readily apparent to those skilled in the art that my portable stair system structure may be modified from those embodiments provided herein, without materially departing from the novel teachings and advantages provided. 
     The aspects and embodiments described and claimed herein may be modified from those shown without materially departing from the novel teachings and advantages provided by this invention, and may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Therefore, the embodiments presented herein are to be considered in all respects as illustrative and not restrictive. As such, this disclosure is intended to cover the structures described herein and not only structural equivalents thereof, but also equivalent structures. Numerous modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention(s) may be practiced otherwise than as specifically described herein. Thus, the scope of the invention(s), as set forth in the appended claims, and as indicated by the drawing and by the foregoing description, is intended to include variations from the embodiments provided which are nevertheless described by the broad interpretation and range properly afforded to the plain meaning of the claims set forth below.

Summary:
An adjustable stair and platform system. The apparatus includes a set of stairs which is affixable to a platform at a first height or alternately at a second height. Both the platform unit and the stair unit include vertically adjustable legs above ground engaging feet. The stairs includes a stair rail frame which is releasably affixable to a side hand rail frame provided for the platform unit. The hand rail frame provided for the platform unit includes an end rail which is pivotally mounted to the side hand rail frame. The end rail frame is changeable to support a right hand or a left hand configuration of the side hand rail frame provided on the platform unit. The combination of vertical adjustability, and left and right hand adjustability, make the unit adaptable for various installation configurations, and avoids the need for multiple stair system units for portable buildings.