Abstract:
Work platform systems and related methods of assembly and use are disclosed herein. In one exemplary embodiment, a method of installing a work platform system into an internal cavity of a structure includes supporting a first platform portion at a first location, and adding a plurality of additional platform portions to the first platform portion, where successive ones of the additional platform portions are respectively positioned at respective locations that are successively farther outward away from the first platform portion. The method further includes coupling the additional platform portions to one or more other locations, and detaching the additional platform portions from one another. The method additionally includes lowering or raising one or more of the first and additional platform portions to one or more additional levels below or above the first level, where the work platform system includes the first and additional platform portions.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    — 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates, generally, to the field of work platforms that are erected to access various parts of various structures. More particularly, the present invention relates to work platforms that can be erected within structures having large internal volume chambers and including, for example, conic structures. 
       BACKGROUND OF THE INVENTION 
       [0003]    A number of types of work platforms are available on the market for use in a variety of environments, circumstances, and projects including, for example, construction or maintenance projects. Whether a project is a public works project (e.g., low bid), or a private project, reducing and/or maintaining costs is critical to the contractor(s) and the owner. One environment in which work platforms are used is within structures providing large internal volume chambers. Such work platforms can be employed for various reasons including, for example, to allow workers to work within the chambers to perform various construction procedures, such as assembling structures within the chamber, and/or various maintenance procedures such as inspecting and cleaning, repairing or refurbishing the interior of the chamber or performing repairs along the internal walls surrounding the chamber. 
         [0004]    Some such structures having large internal chambers in which work platforms are employed are large conical primary separation vessels utilized to extract oil from the oil sands. Such conical structures are downwardly-oriented (downwardly-pointing, or funnel-shaped) cones having a cross-sectional horizontal area that decreases as one moves downwardly from the top of the structure toward the bottom (toward where the tip is located, or would be located if the tip was not removed). Often the heights and diameters of the interior chambers within such conical structures can be quite large, for example, on the order of  50  to more than  100  feet. Due to the abrasive materials processed in these conical structures, these structures require frequent inspections, cleanings, and repairs, for example, to repair worn internal walls (worn down due to exposure to sand/rock) or perform other spot repairs, to weld in steel plating (e.g., particularly near the bottom of the structure), and/or to repair equipment mounted within the interior chambers. 
         [0005]    A desirable work platform in a conical structure such as that mentioned above will have platform portions extended alongside the interior surfaces of the conical structure typically at a variety of height levels within the structure, so as to allow workers to access and execute scope of work to substantial portions of those internal surfaces, or even all or substantially all portions of the internal surfaces. Yet construction of a work platform having portions positioned to allow for satisfaction of these goals is typically costly and time-consuming, both because of the size of the internal chamber and because the shape of the internal walls of the chamber make it difficult to assemble the work platform due to the walls being generally all inclined outward as one progresses upward within the internal chamber. These difficulties are experienced with a number of different types of work platform systems, for example, Regardless of whether the work platform is assembled mostly outside of the conical chamber at a different location and then brought into the conical chamber, or assembled from scratch within the conical chamber. 
         [0006]    For at least these reasons, therefore, it would be advantageous if a new or improved work platform system and/or method of use (e.g., in terms of installing the work platform system) could be developed that addressed one or more of the above-described concerns. 
       SUMMARY OF THE INVENTION 
       [0007]    In at least some exemplary embodiments, the present invention relates to a method of installing a work platform system into an internal cavity of a structure. The method includes supporting a first platform portion at a first location in relation to the internal cavity, and adding a plurality of additional platform portions to the first platform portion, where successive ones of the additional platform portions are respectively positioned at respective locations that are successively farther outward away from the first platform portion along or proximate to a first level. The method further includes coupling the additional platform portions to one or more other locations so that the additional platform portions are supported in relation to the structure, and detaching the additional platform portions from one another. Additionally, the method also includes lowering or raising one or more of the first platform portion and additional platform portions to one or more additional levels below or above the first level, where the work platform system includes the first platform portion and the additional platform portions. 
         [0008]    Further, in at least some additional exemplary embodiments, the present invention relates to a work platform system configured for implementation within a cavity defined by one or more interior walls within a structure. The work platform system includes a starter assembly including at least one component that is configured to be supported at a first location substantially above the cavity and further including a first platform portion coupled to the at least one component, and a plurality of additional platform portions configured to be positioned along or proximate to the one or more interior walls. The work platform system also includes a plurality of suspension components by which the additional platform portions are linked to one or more of the first location and one or more of a plurality of additional locations substantially above the cavity. The first and additional platform portions are respectively positioned so that each respective one of the platform portions is at a respective vertical level along a vertical axis extending through the cavity and through the first platform portion, and successive ones of the additional platform portions are respectively positioned successively outwardly relative to the vertical axis. 
         [0009]    Additionally, in at least some further exemplary embodiments, the present invention relates to a work platform system into an internal cavity of a structure. The method includes supporting a first platform portion in relation to the internal cavity at a first level, and adding a plurality of additional platform portions to the first platform portion, where each of the additional platform portions is respectively positioned substantially concentrically around a respective subset of the first and additional platform portions and each successive one of the additional platform portions is positioned further radially outwardly from the first platform portion. The method also includes coupling the additional platform portions to one or more other locations by way of a plurality of suspension components so that the additional platform portions are supported in relation to the internal cavity in a manner other than by way of the first platform portion, and detaching the additional platform portions from one another. The method additionally includes lowering one or more of the first platform portion and additional platform portions to one or more additional levels below the first level, and interconnecting the first and additional platform portions at the first level and the one or more additional levels by way of additional components that are configured to facilitate movement of personnel or machinery among the platform portions. The first and additional platform portions subsequent to the lowering are arranged so as to conform to an inverted conical shape of the internal cavity. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective, partially cutaway view showing an example structure with a large internal cavity in which a work platform system is to be implemented, which in this example particularly is a downwardly-orientated conical (funnel-shaped) separation vessel where, in accordance with at least one embodiment, a cap with rigid top beams is formed across a top of the vessel linking an outer upper rim of the vessel with a ring in the middle forming an open orifice, along with an upper portion of the work platform system having a starter platform, where the upper portion is suspended above and about to be positioned into the ring corresponding to an initial stage of implementation of the work platform system; 
           [0011]      FIG. 2  is a further perspective, partially cutaway view of the vessel of  FIG. 1  shown with the cap and portions of some of the rigid top beams removed, along with the upper portion of the work platform system now positioned within the ring, as occurs during a subsequent stage of implementation of the work platform system; 
           [0012]      FIG. 3  is a further perspective, partially cutaway view of the vessel of  FIGS. 1 and 2  shown with the cap and some of the rigid top beams or portions of some of those beams removed, along with the starter platform of the work platform system now modified to include additional extension platform portions around it, representative of a further stage of implementation of the work platform system; 
           [0013]      FIG. 4  is an additional perspective, partially cutaway view of the vessel of  FIGS. 1-3  now shown with the cap and a portion of the outer upper rim of the vessel and other conical wall portions of the vessel removed to reveal the work platform system positioned within the vessel in a further stage of implementation in which the starter platform has been modified to include multiple additional extension platform portions around it, the additional extension platform portions substantially forming concentric rings surrounding the starter platform, which is representative of an additional stage of implementation of the work platform system; 
           [0014]      FIG. 5  is a top plan view of several example components employed to form the platform portions of the work platform system, particularly interconnected hub and joist components employed in this regard, as well as several other structures including the rigid top beams of the cap that are positioned above those platform portions; 
           [0015]      FIG. 6  shows in more detail an example hub such as can be used in forming the platform portions of  FIG. 5 ; 
           [0016]      FIG. 7  shows in more detail an example joist such as can be used in forming the platform portions of  FIG. 5 ; 
           [0017]      FIGS. 8A and 8B  respectively show exploded top perspective view and top perspective views of an example interconnection between the hub and joist of  FIGS. 7 and 8 , as can be employed in forming the platform portions of  FIG. 6 ; 
           [0018]      FIG. 9  is a further perspective, partially cutaway view of the vessel of  FIGS. 1-4  where for convenience of illustration the upper portion (aside from the starter platform) is shown to be removed (even though the upper portion should be understood to still be present) and instead various suspension linkages are shown to be present, by which the additional extension platform portions of  FIG. 4  can be understood to be connected to and supported by the rigid top beams of the cap (which, although not shown in  FIG. 5 , should be understood to be present in substantially the form shown in  FIG. 1 ), and additionally where (in contrast to  FIG. 4 ) several portions of the additional extension platform portions are shown to have been removed, in accordance with a subsequent stage of implementation of the work platform system; 
           [0019]      FIG. 10  is a schematic diagram corresponding to the platform portions of the work platform system shown in  FIG. 5 , intended to illustrate example points on the platform portions at which those portions can be suspended from the cap of  FIG. 1 ; 
           [0020]      FIG. 11  is an additional perspective, partially cutaway view of the vessel of  FIGS. 1-4  and  9 , similar to that of  FIG. 9  except insofar as now certain ones of the additional extension platform portions corresponding to a next-to-outermost one of the concentric rings has been lowered downwardly further into the vessel, in accordance with a further stage of implementation of the work platform system; 
           [0021]      FIG. 12  is a cross-sectional schematic view of the vessel and work platform system illustrating yet later stages of implementation of the work platform system within the vessel of  FIGS. 1-4 ,  9 , and  11 , where multiple successive concentric ring portions of the work platform system of successively smaller diameters have been lowered to successively lower levels within the vessel; and 
           [0022]      FIG. 13  is a further perspective, partially cutaway view of the vessel of  FIGS. 1-4 ,  9 , and  11 - 12 , illustrating from another vantage point the arrangement already shown in  FIG. 12 , it being understood that, for clarity, many of the suspension linkages by which various different portions of the work platform system are linked to the cap are not shown. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]      FIGS. 1-4 ,  9 , and  11 - 13  illustrate various steps of an example process of implementing an example work platform system within a structure having a large interior chamber. In the present example embodiment, the structure within which the work platform system is implemented is a downwardly-orientated conical (funnel-shaped) separation vessel  100 , having both a diameter and a height of approximately  50  to  100  feet, as is used in the oil sands industry particularly for the purpose of separating oil from oil sand. As shown, the separation vessel  100  particularly includes a top rim  102  that is circular, and a conical wall  104  that extends downward from the top rim to a bottom tip region  106  that extends downward somewhat off of the conical wall. As shown, the conical wall  104  is shaped and orientated such that its cross-sectional horizontal area decreases as one moves downwardly from the top rim  102  of the structure toward the bottom (toward where the bottom tip region  106  is located, or would be located if the tip was not removed). Although this progression occurs smoothly and in uniform manner as shown, in other embodiments the conical wall  104  can be generally conical while still having features that are not conical (for example, a portion of the wall that juts outward from the remainder of the wall). 
         [0024]    Notwithstanding that the description provided herein particularly focuses upon implementation of a work platform system within the vessel  100 , this is only intended as an example. Indeed, it should be appreciated that the same or similar (or substantially similar) processes for implementing work platform systems, and/or the same or similar (or substantially similar) work platform systems and/or associated component(s), can be utilized in connection with a variety of other types of structures having large internal chambers within which the work platform systems are to be erected, positioned, or otherwise implemented. For example, while the vessel  100  is a conical structure having the top rim  102  that is circular, in other embodiments, the structure within which the work platform system is implemented can be a downwardly-orientated pyramidal structure (e.g., with a top rim that takes the shape of a square, rectangular, or some other polygon). Also, it is envisioned that the same or similar (or substantially similar) work platform systems, and/or the same or similar (or substantially similar) work platforms and/or associated components, can be utilized in relation to other structures having large internal chambers, even where those structures have walls that do not progress inwardly towards one another as one proceeds downward from the top of the structure to the bottom of the structure. In particular, encompassed herein are also embodiments in which the work platform systems are configured to be implemented in a conical structure or polygonal structure in which the walls of the structure proceed inwardly toward one another as one proceeds upwardly rather than downwardly (e.g., the tip of the structure is at the top rather than the bottom). 
         [0025]    Referring particularly to  FIG. 1 , in the present embodiment, the process of implementing a work platform system within the vessel  100  begins by provision of a cap  108  extending over the top rim  102  of the vessel. As shown, the cap  108  more particularly includes a plurality of rigid top beams (or roof rafters)  110  extending inwardly from the top rim  102 , upon which those beams (and the cap) are supported, up to an inner ring  112  forming on orifice (or oculus)  114  in the middle of the cap. A vertical axis  115  extends from the bottom tip region  106  of the vessel  106  all of the way through the vessel up through the center of the orifice  114  (an arrow  117  also shown to be along this axis is discussed further below). In the present embodiment, an annular roof or ceiling portion  116  rests upon the rigid top beams  110  so as to extend inward from the top rim  102  to the inner ring  112 .  FIG. 1  particularly shows a portion of the annular roof  116  removed to better reveal some of the beams  110  (which are otherwise shown in phantom), albeit it should be understood that the annular roof forms a complete annulus extending around the ring  112 . Although in the present embodiment the cap  108  and its various subcomponents  110 ,  112 ,  114 ,  116  can be considered a part of the work platform system, it can also alternatively be considered a part of the vessel  100  that preexists establishment of the work platform system. 
         [0026]    Further as shown in  FIG. 1 , the beginning of the process of the implementing of the work platform system additionally includes provision of a starter assembly  118  having a hexagonal starter platform portion (or simply starter platform)  120  suspended beneath a square (or rectangular) spreader frame assembly  122 . The connection of the starter platform  120  to the spreader frame assembly  122  can be achieved using suspenders or linkages  124 , which in the present embodiment are flexible linkages such as chains or wire ropes but, in alternative embodiments, can also or instead be achieved using other types of linkages such as rigid bars. In the present embodiment, there are six of the linkages  124  linking each of the corners of the hexagonal starter platform to corresponding locations along the spreader frame assembly  122 . The starter assembly  118  overall is suspended from a crane or other lifting mechanism (not shown), by way of additional suspenders  126  attached to four corners  128  of the spreader frame assembly  122  that are all coupled to an ultimate hoisting linkage  130  (shown in cutaway), which in turn is coupled to the crane or other lifting mechanism. In at least one embodiment, the linkages  124  and hoisting linkage  130  are chains that are all connected to one another by way of one or more chain links or loops. 
         [0027]    Turning to  FIG. 2 , at a second step in the process of implementing the work platform system, by virtue of appropriate lowering of the starter assembly  118  by way of the crane or other lifting mechanism, the starter assembly  118  is lowered into and through the ring  112  (e.g., in a direction as indicated by an arrow  117  shown in  FIG. 1 ) so that the spreader frame assembly  122  rests upon the top of the ring and is supported thereon. More particularly, it will be noted from  FIG. 2  that the corners  128  of the spreader frame assembly  122  particularly extended outward over the ring  112  so that the ring can support the spreader frame assembly, while the linkages  124  extend downward through the ring and into an interior chamber  200  within the vessel  100  and covered by the cap  108 , such that the starter platform  120  particularly is then positioned within that interior chamber. To better illustrate the relative positioning of these structures in this regard, the annular roof  116  is no longer shown in  FIG. 2  and portions of the beams  110  (particularly portions of the beams by which the beams are coupled to the ring  112 ) are cutaway, albeit it should be understood that in actuality these missing structures are in fact present. 
         [0028]    Turning next to  FIG. 3 , a further perspective, partially cutaway view of the vessel  100  of  FIGS. 1 and 2  is shown with the roof  116  and several of the beams  110  and portions of the beams removed for simplicity of illustration (albeit again it should be understood that the missing roof and beams/beam portions in fact are present). As shown in  FIG. 3 , once the starter assembly  118  is in position as shown in  FIG. 2  such that the starter platform  120  is within the interior chamber  200  at a sufficiently low level that the starter platform level coincides with the level within the chamber having the largest horizontal cross-sectional area or diameter (e.g. at the level of the rim  102 ), additions can be made to the starter platform. More particularly in this regard,  FIG. 3  illustrates a step of the process of implementing the work platform system in which a first additional platform portion  300  has been added around the starter platform  120 . As shown, the first additional platform portion  300  particularly includes a series of main platform portions  302  that are positioned immediately around the starter platform  120  so as to form a first platform ring  304 , as well as a series of intermediate portions  306  that are positioned immediately around that platform ring formed by the main platform portions  302  so as to form a further intermediate ring  308 . 
         [0029]    Although the first additional platform portion  300  is described as encompassing the rings  304  and  308 , it will be observed that, more accurately speaking, main platform portions  302  and intermediate portions  306  encompass rectangular/square and triangular portions that in combination with one another approximate an annular shape without being exactly annular. That is, the main platform portions  302  provide a ring-like structure (the ring  304 ) having six sides internally, adjacent the six sides of the hexagonal starter platform  120 , while having twelve sides or a dodecagon-shape externally, while the intermediate portions  306  provide a ring-like structure (the ring  308 ) having twelve sides internally and twenty-four sides externally. Notwithstanding these particular shapes, it should be understood that numerous other arrangement are possible depending upon the embodiment, and this particular arrangement is partly reflective of the use of the hexagonal starter platform  120 . 
         [0030]    As also illustrated, the first additional platform portion  300  is suspended vertically by way of additional linkages  310  by which that additional platform portion is connected to ones of the beams  110 . In  FIG. 3 , due to the manner in which the beams  110  are illustrated, several of the additional linkages  310  are shown in cutaway, albeit it should be understood that these additional linkages are in actuality coupled to those of the beams that are directly above those additional linkages. In the embodiment shown, the additional linkages  310  particularly link each of the outer corners of the ring  304  (twelve in all) with corresponding ones of the beams  110 , although in other embodiments linking connections can be established at or with other points/sections of the additional platform portion  300 . Also, depending upon the embodiment, the additional linkages  310  can take a variety of forms, for example, flexible linkages or suspenders such as wire rope or chain linkages, and/or other types of linkages such as rigid linkages. 
         [0031]    Referring to  FIG. 4 , the implementation of the work platform system continues with further additional platform portions being constructed (mounted) circumferentially around the starter platform  120  and the first additional platform portion  300 . In particular, in the present embodiment, a second additional platform portion  400  is formed that includes main platform portions  402  that form a second platform ring  404  surrounding the ring  308 , as well as intermediate platform portions  406  that form a second intermediate ring  408  that surrounds the second platform ring. Further, a third additional platform portion  410  is formed that includes main platform portions  412  that form a third platform ring  414  surrounding the second intermediate ring  408  and intermediate platform portions  416  that form a third intermediate ring  418  that surrounds the third platform ring. Further, a fourth additional platform portion  420  is formed that includes main platform portions  422  that form a fourth platform ring  424  surrounding the third intermediate ring  418 , and intermediate platform portions  426  that form a fourth intermediate ring  428  that surrounds the fourth platform ring. Additionally, a fifth additional platform portion  430  is formed that includes main platform portions  432  that form a fifth platform ring  434  surrounding the fourth intermediate ring  428  (the fifth additional platform portion does not, however include any intermediate platform portions or intermediate ring). As illustrated, the fifth platform ring  434  extends up to, or nearly up to, the top rim  102  in the present embodiment. It should be appreciated from the above description that the “platform rings” can be considered platform portions as well. 
         [0032]    Thus, an overall platform structure  440  is formed from the combination of the starter assembly  118  along with the combination of all of the aforementioned platform portions, including both the starter platform  120  and all of the nine rings concentrically positioned surrounding the starter platform, namely, the rings  304 ,  308 ,  404 ,  408 ,  414 ,  418 ,  424 ,  428 , and  434 . As illustrated, each successive one of the rings  304 ,  308 ,  404 ,  408 ,  414 ,  418 ,  424 ,  428 ,  434  is positioned successively radially outwardly away from the starter platform  120  and the vertical axis  115  extending through the vessel  100  (likewise, this can also be said of the platform portions  302 ,  306 ,  402 ,  406 ,  412 ,  416 ,  422 ,  426 ,  432  of those successive rings, as well as the successive additional platform portions  300 ,  400 ,  410 ,  420 ,  430  each encompassing one or more of those rings). To facilitate illustration of all of the additional platform portions  300 ,  400 ,  410 ,  420 ,  430 ,  FIG. 4  only shows rear portions of the top rim  102  and the conical wall  104  of the vessel  100  (the remaining portions cutaway), and the entire cap  108  aside from the ring  112  is also removed. Nevertheless, it should be understood that, in actuality, the cap  108  and vessel  100  are present in their entirety (e.g., as shown in  FIG. 1 ). 
         [0033]    Referring to  FIG. 5  in addition to FIG.  4 ., it should be appreciated that the overall platform structure  440  includes both internal/underlying support components (e.g., a “skeleton”) as well as exterior surface components resting atop (and/or, in alternate embodiments, possibly beneath) those internal support components, which serve as surfaces upon which persons (e.g., work personnel) can walk and/or upon which tools or machinery can be supported and moved.  FIG. 4  particularly shows the exterior surface components, which typically are flat panel portions. That is, the references to the platform portions  302 ,  306 ,  402 ,  406 ,  412 ,  416 ,  422 ,  426 ,  432  can be equally understood to be references to panel portions that are provided at those respective locations as part of the platform portions. Various ones of such panel portions can be made of different materials depending upon the embodiment. In at least some embodiments, the panel portions employed in forming the platform portions  406 ,  416 ,  426  associated with the intermediate rings  408 ,  418 ,  428  can be made of plywood while the panels employed in forming the platform portions  302 ,  402 ,  412 ,  422 ,  432  associated with the platform rings  304 ,  404 ,  414 ,  424 ,  434  (as well as possibly the starter platform  120 ) can be made of sheet metal or plastic that is more robust. Such an arrangement is particularly appropriate insofar as, as will be discussed further below, the process of erecting the work platform system ultimately involves the separation of the platform rings  304 ,  404 ,  414 ,  424 ,  434  from one another and from the starter platform  120  so as to be spaced at different vertical levels within the vessel  100 . 
         [0034]    Referring particularly to  FIG. 5 , example components  500  employed to form the underlying/internal supporting portions (e.g., the “skeleton”) of the overall platform structure  440 , particularly interconnected hub components (or simply hubs)  510  and joist components (or simply joists)  530  employed in this regard, are shown along with the rigid top beams  110  and ring  112  of the cap  108  that are positioned above the overall platform structure. For simplicity of illustration, the vessel  100  is not shown in this illustration, nor is the roof  116  of the cap  108  (nor are the panels discussed above, which are supported upon these hub and joist components), albeit such structures/components should be understood to be present in actuality. In the present embodiment, the rigid top beams  110  particularly are shown to include thirty-six (36) beams extending outward radially from the ring  112  and spaced equidistantly from one another in terms of the distances and angular spacing between adjacent beams. Further, the starter platform  120  is also shown to be internally assembled from a series of interconnected ones of the hubs  510  and joists  530  as are described further in detail with respect to  FIGS. 6 ,  7 , and  8 A- 8 B. 
         [0035]    Turning then to  FIGS. 6 and 7 , there is illustrated in more detail an example of one of the hubs  510 , as well as one of the hubs  510  in connection with a given one of the joists  530 . A joist can be considered any elongate structural member adapted for bearing or supporting a load, such as a bar joist, truss, shaped-steel (i.e., I-beam, C-beam, etc.), or the like. The hub  510  is configured so that, when attached to one of the joists  530 , the hub  510  is capable of articulation relative to the joist  530  (and vice-versa). A hub is an interconnection structure, such as a node, hinge, pivot, post, column, center, shaft, spindle, or the like. Articulation, as used herein, is defined as the capability to swing, and/or rotate, about a pivot point or axis. This articulation feature among other things allows for less manpower to readily assemble and disassemble components of the system in, or near, the desired finished position. 
         [0036]    The hub  510  includes a top element  511  and a bottom element  512  spaced at distal ends of a middle section  515 . The top element  511  and bottom element  512  can be substantially planar in configuration, as well as parallel to each other. The top element  511  and bottom element  512 , in the embodiment shown, are substantially planar surfaces that are octagonal in shape (as viewed from a plan view). The middle section  515  can be a cylindrical section where a longitudinal axis of the middle section  515  is normal to the planes of the top element  511  and bottom element  512 . In the embodiment shown, the middle section  515  is a right circular cylinder. In  FIG. 6 , a lower portion of the middle section  515  is removed for clarity to reveal that the middle section  515  is hollow. 
         [0037]    Further as shown in  FIG. 6 , there are a plurality of openings  513 ,  514 , extending through both the top element  511  and bottom element  512 , respectively. The plurality of openings  513  (e.g.,  513 A,  513 B,  513 C,  513 D,  513 E,  513 F,  513 G,  513 H) are interspersed on the top element  511  so as to offer various locations for connecting to one or more of the joists  530  (see, e.g.,  FIG. 7 ). The plurality of openings  514  (e.g.,  514 A,  514 B,  514 C,  514 D,  514 E,  514 F,  514 G,  514 H) are similarly spaced on the bottom element  512  so that respective pairs of the openings  513  and  514  (e.g.,  513 A and  514 A) are coaxial. Also as shown, at the center of the top element  511  is a center opening  516  which is configured to receive a linkage or suspension connector (such as the linkages  124 ,  310  mentioned above) by which the hub  510  can be suspended from the beams  110  or the spreader frame assembly  122 . 
         [0038]    The center opening  516  can be generally cruciform in configuration with a center opening area  519  and four slots  517  (e.g.,  517 A,  517 B,  517 C,  517 D) extending therefrom. Transverse to each of the four slots  517 A,  517 B,  517 C,  517 D, and interconnected thereto, are also a series of cross slots  518 A,  518 B,  518 C,  518 D. For added strength a reinforcing plate  520  is added to the underside of the top element  511 , where openings on the reinforcing plate  520  correspond to (and are generally coextensive with) the center opening  516  configuration and all the ancillary openings thereto (e.g., the slots and area  517 ,  518 ,  519 ). A handle  522  is optionally added to a side of the middle section  515 . Although not visible in  FIGS. 6 and 7 , it should be appreciated that an identical opening is formed on the bottom element  512 , and the bottom element along its top side can likewise include a reinforcing plate with the same opening. Also not shown, attached to the reinforcing plate along the bottom element  512  and the interior face of the middle section  515  can be a plurality of gussets that provide added support to the hub  510 . 
         [0039]      FIG. 7  depicts a top perspective view of the interconnection between a single one of the hubs  510  and a single one of the joists  530 , while  FIGS. 8A and 8B  show an exploded close-up view, and a regular (unexploded) perspective close-up view, respectively, of a typical connection between the hub  510  and joist  530 . As shown, the joist  530  includes an upper element  532  and a bottom element  533 . Interspersed between the elements  532 ,  533  are a plurality of diagonal support members  538 . Each of the elements  532 ;  533  is made of two L-shaped pieces of angle iron  539 A,  539 B. The elements  532 ,  533  typically can be identical in construction, with the exception being that the upper element  532  includes connector holes  554 A,  554 B at its midspan. The joist  530  includes a first end  531 A and a second end  531 B. At each of the ends  531 A,  531 B of both the upper element  532  and bottom elements  533 , there extends an upper connecting flange  535  and a lower connecting flange  536 . Additionally, through each of the upper and lower connecting flanges  535 ,  536 , there are connecting holes  537 . Thus, there are four upper connecting flanges  535 A,  535 B,  535 C,  535 D and four lower connecting flanges  536 A,  536 B,  536 C,  536 D on the joist  530 . 
         [0040]    Thus, at a first end  531 A, extending from the upper element  532 , is an upper connecting flange  535 A and lower connecting flange  536 A, with a connecting hole  537 A therethrough (see also  FIG. 8A ). Similarly, at the second end  531 B of the upper element  532 , there extends an upper connecting flange  535 B and lower connecting flange  536 B, with a connecting hole  537 B therethrough. Also, at the first end  531 A of the lower element  533  there extends an upper connecting flange  535 D and lower connecting flange  536 D. Through these connecting flanges  535 D,  536 D are a connecting hole  537 D. Further at the second end  531 B of the joist  530  extending from the lower element  533  is an upper connecting flange  535 C and lower connecting flange  536 C with a connecting hole  537 C therethrough. In addition to the respective connecting holes  537 A,  537 B,  537 C,  537 D, each of the connecting flanges  535 A,  535 B,  535 C, and  535 D additionally includes a respective additional locking hole  360 A,  360 B,  360 C,  360 D, respectively, all of which are located inwardly of the respective connecting holes (that is, axially toward the center of the joist  530  relative to the connecting holes). 
         [0041]    Further as shown in  FIGS. 8A and 8B , pins  540  can be placed through the connecting holes  537  of the connecting flanges  535 ,  536  at each of the first end  531 A and second end  531 B of the joist  530  and further through any two corresponding ones of the openings  513 ,  514  of the hub  510 .  FIGS. 8A and 8B  particularly show one of the pins  540  employed at the first end  531 A, it being understood that the same or substantially same arrangement can be present at the end  531 B. In this manner, the joist  530  can be connected in a virtually limitless number of ways, and angles, to the hub  510 . For example, as shown particularly in  FIGS. 8A and 8B , one of the pins  540  can be placed in through the connecting flange  535 A, through the opening  513 A, through the connecting flange  536 A (all at the first end  531 A of the upper element  532 ), through the connecting flange  535 D, through the opening  514 A, and then through the connecting flange  536 D. In this scenario, the pin  540  further threads through connecting holes  537 A and  537 D. 
         [0042]    The pin  540  additionally includes two roll pins  542  at its upper end. The lower of the two roll pins  542  acts as a stop, thereby preventing the pin  540  from slipping all the way through the joist  530  and hub  510 . The upper roll pin  542  acts as a finger hold to allow easy purchase and removal of the pin  540  from the joist  530  and hub  510 . The design of these various parts are such that free rotation of both the joist  530  and hub  510  is allowed, even while the joist  530  and hub  510  are connected together. Rotational arrows R 1  of  FIGS. 7 and 8B  show the rotation of the joist  530  relative to the hub  510 , while rotational arrows R 2  show the rotation of the hub  510  relative to the joist  530  of  FIGS. 7 and 8B . These rotational capabilities of the joist  530  and hub.  510  relative to one another provide, in part, the articulating capability of the present design. 
         [0043]    Although articulation of the joist  530  and hub  510  relative to one another can occur in some embodiments, in other embodiments including an embodiment as shown in  FIGS. 8A and 8B , such articulation is precluded due to the presence of optional locking pins, one of which is shown as a locking pin  540 B. As shown, the locking pin  540 B can be added through the locking holes  360 A and  360 D proximate the end  531 A of the joist  530  in order to lock the joist  530  in relation to the hub  510  to prevent relative articulation, if so desired. The locking pin  540 B particularly operates to preclude such articulation (at least in part) due to contact with the hub  510  along two of several grooves (or slots/dimples)  524  formed along the perimeters of the upper element  511  and lower element  512  of the hub  510 . Because the locking pin  540  extends through two of the grooves  524 , the locking pin effectively is prevented from moving around the perimeters of the upper and lower elements  511 ,  512  and correspondingly prevents such movement of the joist  530  relative to the hub  510 . 
         [0044]    As with the pin  540 , the locking pin  540 B can include additional two roll pins  542  as shown, which serve the same purposes as discussed above with respect to the roll pins provided on the pin  540 . Although not shown in  FIGS. 8A and 8B , it should be likewise understood that another of the locking pins  540 B can similarly be added through the locking holes  360 B and  360 C proximate the end  531 B (see  FIG. 7 ) of the joist  530  when that end is connected to another one of the hubs  510  by another of the pins  540 . Indeed, notwithstanding the above description of the hubs  510 , joists  530 , and associated components shown in  FIGS. 6 ,  7 ,  8 A, and  8 B, it should be appreciated that these components are only example components that can be employed among the components  500  forming the underlying/internal supporting portions (e.g., the “skeleton”) of the overall platform structure  440 . Further, the overall platform  440  can include a variety of other components in addition to, and/or instead of, the components  500  and panel portions already discussed above. 
         [0045]    Further in this regard, among other things, various differently-shaped components can be utilized. For example, while joists such as the joist  530  can be bar joists, the joists can also be open-web joists and/or structural tubing. Further for example, one or more of the joists  530  can be made of multiple pieces of structural tubing shapes, or the joists  530  can be one single structural tubing shape. Similarly, the joist  530  could be made of shaped steel (e.g., wide flange elements, narrow flange members, etc.), or other suitable shapes and materials. Also, additionally other types of joists that are curved rather than linear (straight) can be employed, as can other types of panel portions and supports for such panel portions. Additionally in this regard, depending upon the embodiment, other components can be employed such as any of those described in U.S. Pat. No. 7,779,599 entitled “Articulating Work Platform Support System, Work Platform System, and Methods of Use Thereof”, issued on Aug. 24, 2010, which is hereby incorporated by reference herein (said issued patent being assigned to a common assignee with the present patent application). 
         [0046]    Turning now to  FIG. 9 , a further perspective, partially cutaway view of the vessel  100  of  FIGS. 1-4  is shown, where the work platform system being constructed therein is shown in yet a later stage of assembly (later than that of  FIG. 4 ). For convenience of illustration, similar to  FIG. 4 ,  FIG. 9  only shows rear portions of the top rim  102  and the conical wall  104  of the vessel  100  (the remaining portions cutaway), and the entire cap  108  is also removed. Further, the upper portions of the starter assembly  118  (e.g., the spreader frame assembly  122 ) are also not shown. Nevertheless, it should be understood that, in actuality, the cap  108 , the vessel  100 , and the starter assembly  118 , are present in their entirety (e.g., as shown in  FIG. 1 ). At the same time, by contrast with  FIG. 4 , the work platform system is shown to be in a later stage of assembly insofar as now several sets of linkages  904 ,  914 ,  924 , and  934  are shown to have been added, which are in addition to the linkages  124  of the starter assembly  118  itself and the additional linkages  310  already discussed with respect to  FIG. 3 . 
         [0047]    More particularly, it should be appreciated that the respective sets of linkages  310 ,  904 ,  914 ,  924 ,  934  connect the additional platform portions  304 ,  404 ,  414 ,  424 ,  434 , respectively, to the beams  110  of the cap  108 . These connections of the additional platform portions  304 ,  404 ,  414 ,  424 ,  434  to the beams  110  by way of the linkages  310 ,  904 ,  914 ,  924 ,  934  should be understood to be present even though, for simplicity of illustration, the portions of the linkages directly linked to the beams are not shown (since the cap  108  with the beams itself is not shown). The linkages  904 ,  914 ,  924 ,  934  can take a variety of forms depending upon the embodiment, in the same manner as discussed above to the linkages  124  and additional linkages  310 . For example, each of the linkages  904 ,  914 ,  924   934  can be flexible linkages (e.g., wire rope linkages or chain linkages) or rigid rod linkages. Relatedly, the intermediate rings  308 ,  408 ,  418 ,  428  previously linking those additional platform portions with one another are shown to have been removed. Thus, in this stage of construction of the work platform system, the additional platform portions  304 ,  404 ,  414 ,  424 ,  434  are all supported via the linkages  310 ,  904 ,  914 ,  924 ,  934  rather than by the starter assembly  118  as shown in  FIG. 4 . 
         [0048]    Referring next to  FIG. 10 , a schematic diagram  1000  is provided illustrating example placement of the linkages  124 ,  310 ,  904 ,  914 ,  924 ,  934  in relation to the rigid beams  110  and ring  112  of the cap  108 . More particularly as shown, several different types of linkages can be employed to support portions of the overall platform  440  depending upon the exact circumstance. Circular locations  1004  particularly indicate locations where hoist locations can be provided. Triangular locations  1006  indicate locations where suspension chain connections can be provided to existing rigid beams  110  (rafters), which are required for stabilizing all remaining platform rings during erection (which are to be removed after all remaining permanent suspension linkages have been installed). Finally, square locations  1008  are indicative of where beam clamp connections are located on the rigid beams  110  (rafters). 
         [0049]    Further with respect to  FIG. 10 , an outline  1002  is also provided showing example positioning of a catwalk that in at least some embodiments can be present. Although the catwalk is not illustrated in  FIGS. 1-9 , it should be appreciated from a comparison of  FIG. 10  with one or more of the  FIGS. 1-9  that the catwalk as represented by the outline  1002  can extend over the platform structure  440  from a location at or proximate to the exterior of the vessel  100  such as the top rim  102  (or even from an interior surface of a portion of the cap  108 ) inward to the starter platform  120 . Given such an arrangement, such a catwalk can allow for personnel to cross over to the starter platform  120  when the starter platform is first in place (e.g., at the step represented by  FIG. 2 ) so as to then attend to assembly of the various additional platform portions  300 ,  400 ,  410 ,  420 ,  430 . In at least some such circumstances the catwalk leads to a location above the starter platform  120 , after the starter platform has already been lowered to a level beneath the catwalk, and there is provided a ladder or similar structure allowing for personnel to then climb down to the starter platform, so as to then build out the entire remainder of the overall platform portion  440  corresponding to all of the additional platform portions  300 ,  400 ,  410 ,  420 ,  430 . 
         [0050]    Alternatively, given that the overall platform portion  440  is assembled incrementally from the numerous ones of the hubs  510  and joists  530 , in other embodiments a portion or portions of the overall platform portion are built out above or at the level of the catwalk, those assembled portion(s) are then lowered to a level beneath the catwalk, and then the remaining portion(s) of the overall platform portion are added at that time to complete the overall platform portion. For example, in some embodiments, the additional platform portion  300  but not the additional platform portions  400 ,  410 ,  420 ,  430  are formed at a level at or above that of the catwalk but the remaining additional platform portions are formed at a level below that of the catwalk. Alternatively (and/or additionally), in some embodiments, a portion of a circular platform with sector removed (e.g., a portion of one or more of the additional platform portions  300 ,  400 ,  410 ,  420 ,  430  forming a major sector of a circular platform) is built out at or above the level of the catwalk  502 , but the remaining portion (e.g., a minor sector) is left unfinished at that time so that the partially-finished portion of the circular platform can be lowered beneath the catwalk and clear the catwalk during the lowering process, after which the remaining portion of the circular platform portion is finally added so as to complete the overall platform portion  440 . 
         [0051]    Turning to  FIG. 11 , an additional perspective, partially cutaway view is provided that, although similar to  FIG. 9  in most respects, shows the work platform system at a further stage of construction within the vessel  100 . More particularly, in this stage of construction, the platform portions  422  corresponding to the further platform ring  424  have been lowered downwardly further into the vessel, even while all the remaining platform portions remain at the level of the starter platform  120 . Particularly to allow this lowering, the linkages  924  connecting the platform ring  424  with the rigid beams  110  (see  FIG. 1 ) are lengthened (it will be noted that the other linkages for suspending the other rings have been omitted for convenience of illustration, even though such linkages actually will be present). It should be appreciated that, given the shape of the conical wall  104 , the platform portions  422 /fourth platform ring  424  are lowered only so far as the outer edge of those components is in contact with or in close proximity to the interior surface of the conical wall. If not in contact with the interior surface of the conical wall  104 , the platform ring  424  can be the same distance from the conical wall as the outer edge of the ring  434  is from the rim  102  of the vessel  100 . Thus, the platform ring  424  is able to be lowered a suitable distance below the ring  434  as determined by the shape of the conical wall  104 , but not able to be lowered all of the way to the bottom of the vessel  100 . 
         [0052]    Although the platform ring  424  can only be lowered to a certain level as illustrated in  FIG. 11 ,  FIG. 12  shows how in additional stages (or steps) of the construction process several of the other platform portions are lowered to successively lower levels within the vessel  100 . That is,  FIG. 12  not only shows the platform ring  424  to have been lowered, beneath a first level  1202  at which the ring  434  remains, to a second level  1204  as represented by an arrow  1214 , but also shows the platform rings  414 ,  404 ,  304  (including the starter platform  120 ) to have been lowered to third, fourth, and fifth levels  1206 ,  1208 , and  1210 , respectively, beneath the first level  1202 . The lowering of each of the respective platform rings  414 ,  404 , and  304  to the third, fourth, and fifth levels  1206 ,  1208 , and  1210 , respectively can be understood to occur at each of several successive stages (or steps) of the construction process, as represented by arrows  1216 ,  1218 , and  1220 , respectively. As illustrated, the lowering of each of the respective platform rings  414 ,  404 ,  304  is accomplished by adjusting or elongating the respective linkages  914 ,  904 , and  310  by which those platform rings are connected to and supported by the rigid beams  110  of the cap  108 . Insofar as the starter platform  120  remains coupled to the platform ring  304 , the linkages  102  by which the starter platform is linked to the spreader frame assembly  122  also are appropriately adjusted/elongated. Notwithstanding the lowering of the various platform portions, all of the successive platform portions can be said to be positioned radially outwardly in succession relative to the starter platform  120  and vertical axis  115  (as shown in  FIG. 4 ). 
         [0053]    Upon accomplishment of all of the stages of assembly described above with respect to  FIG. 12 , the various rings  434 ,  424 ,  414 ,  404 ,  304  (including starter platform  120 ) are all in final positions as shown in  FIG. 12  and, in perspective view, additionally in  FIG. 13 . For convenience of illustration,  FIG. 13  again shows a further perspective, partially cutaway view of the vessel  100  in which only rear portions of the top rim  102  and the conical wall  104  of the vessel  100  are shown (the remaining portions cutaway), and also only portions of the cap  108  are shown (particularly, several of the rigid beams  110  and a cutaway portion of the ring  112 ). Further, only the linkages  102  connecting the starter platform  120  to the spreader frame assembly  122  are shown. Nevertheless, it should be understood that, in actuality, the cap  108 , the vessel  100 , and all of the linkages discussed with respect to  FIG. 12  (that is, including the linkages  310 ,  904 ,  914 ,  924 ,  934 ) are present in their entirety. Further as shown,  FIG. 13  is representative of a final stage of assembly in which ladders  1302  have been added to connect the various rings  434 ,  424 ,  414 ,  404 ,  304  so as to allow workers  1304  to climb easily up and down between the different levels  1202 ,  1204 ,  1206 ,  1208 ,  1210  at which the various rings are located (the ladder linking the rings  404  and  304  being shown partly in phantom). Given the addition of the ladders  1302  and the finalized positioning of the various rings  434 ,  424 ,  414 ,  404 ,  304  (including the starter platform  120 ), the work platform assembly  1310  within the vessel  100  can be said to be in its finished form. 
         [0054]    It should be appreciated that the work platform assembly  1310  described above is only intended as an example and that the present invention is intended to encompass numerous variations of the above-described work platform assembly, components thereof, and/or method of assembly and/or utilization. For example, while the work platform assembly  1310  includes five different work platform levels (that is different platform sections provided at the different levels  1202 ,  1204 ,  1206 ,  1208 ,  1210 ), in other embodiments there can be other arbitrary numbers of work platform levels. Also, the spacing of the work platform levels need not be consistent between different pairs of levels, and/or can vary depending upon the implementation or embodiment. Further although the work platform system  1310  shown in  FIG. 13  is made of five different generally annular (more particularly polygonal annular) structures, namely, the rings  434 ,  424 ,  414 ,  404 ,  304  (where the lowest ring also includes the starter platform  120 ), in other embodiments one or more of the different structures making up the work platform system need not be a complete annulus but can be a portion of an annulus (e.g., a structure extending halfway around the interior of the conical wall  104 ) or be shaped in numerous other manners. 
         [0055]    The particular shapes of the different structures of a given work platform system can vary also depending upon the size and shape of the vessel  100  or other structure within which the work platform is constructed. For example, depending upon the embodiment, the various platform portions described above can take on any of a variety of rectangular, triangular, or other polygonal shapes (further for example, the starter platform could be octagonal rather than hexagonal) or even possibly shapes other than polygonal shapes, and further the spreader frame assembly  122  need not be rectangular in all embodiments but can also take on a different polygonal or other shape. Further, as already noted, the work platform system can be configured for implementation in a conical or polygonal structure having walls that proceed inwardly toward one another as one proceeds upward rather than downward. In such implementations, the above-described process of implementing the work platform can be inverted from that discussed above. That is, in such implementations, successively inwardly-positioned portions of the work platform are raised to successively-higher positions within the conical or other structure, rather than lowered. 
         [0056]    The materials out of which the work platform system  1310  or other work platform systems in other embodiments can be formed can vary depending upon the embodiment. For example, suitable materials for components of such work platform systems can include metal (e.g., steel, aluminum, etc.), wood, plastic, composite, or other suitable materials. Also, such components can be made of items that are solid, corrugated, grated, smooth, or of other suitable configurations. For example, panel portions of such work platform assemblies can be made of wood sheeting, plywood, roof decking material, metal on a frame, grating, steel sheeting, and the like, among other things. Also, it should be appreciated that a variety of types of linkages can be employed in supporting platform portions relative to the cap/rigid beams/rafters/spreader frame assembly, and/or other support structures. The linkages can be flexible, such as wire, wire rope, chain, or similar types of linkages, as well as in some cases rigid. 
         [0057]    In at least some embodiments, work platform systems such as the work platform system  1310  are advantageous in that, because the work platform system is formed from multiple discrete components such as the hubs  510 , joists  530 , and associated panel portions, worker(s) can modify or add to existing portions of the work platform system while physically supported upon an existing, installed portion of work platform system. In at least some embodiments, worker(s) in such a circumstance can extend, relocate, or remove components of the work platform system using only hand tools, and no mechanical tools, hoists, cranes, or other equipment is required to add to, or subtract from, existing components of the work platform system. In at least some embodiments, installation of a work platform system can be done, essentially, “in the air”. That is, the work platform system can be erected and connected together “in the air”, in a piece-by-piece order via the use of multiple pieces of lifting, or hoisting, equipment. That said, in alternate embodiments, it is possible also that one or more of the hubs  510 , joists  530 , panels, and/or other components will be preassembled on the ground, or at a remote location, and then moved and hoisted as a pre-assembled module into the desired location (e.g., into a structure such as the vessel  100 , where in some cases the cap  108  can also be provided as part of the pre-assembled structure). 
         [0058]    Although not discussed above, in other embodiments other types of components can be also included in a work platform system. For example, in some embodiments, a railing system can be attached to one or more platform portions. Railings of such systems can be manufactured from a variety of materials, such as chain, cable (e.g., galvanized aircraft cable), line, and the like, among other things. For example, the railing  88  may be galvanized aircraft cable. In still additional embodiments, railing standards can also be used to erect a work enclosure system. For example, tarps, sheeting, or the like can be attached to railing standards to enclose work area(s) for various purposes. 
         [0059]    Therefore, although certain embodiments of the present invention have been shown and described in detail above, it should be understood that numerous changes and modifications can be made without departing from the scope of the appended claims. Among other things, it should be appreciated that the scope of the present invention is not limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc., as described above, but rather the above disclosures are simply provided as example embodiments. 
         [0060]    Thus, it is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.