You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority from provisional patent application Ser. No. 60/191,704, filed Mar. 23, 2000; and is a continuation-in-part of co-pending U.S. patent application Ser. No. 09/394,595, filed Sep. 13, 1999, which is a continuation-in-part of U.S. patent application Ser. No. 08/870,101, filed Jun. 5, 1998, the entire contents of all of which are incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention is directed to a knock-down hand rail system. More particularly, the present invention relates to a unique knock-down hand rail system for use both indoors and outdoors.  
         BACKGROUND OF THE INVENTION  
         [0003]    The typical hand rail is formed of metal and susceptible to affects of weather or other environmental conditions causing the rail to rust and deteriorate. A disadvantage of these metal rails is that such rails require regular upkeep such as painting to prevent rust or complete replacement when the metal rusts away.  
           [0004]    To overcome this, galvanized steel has been used to avoid rust and hopefully, eliminate regular upkeep. A disadvantage of galvanized steel is that the sheen is too bright and is distracting when used in environments such as auditoriums or stadiums.  
           [0005]    A still further disadvantage of both the metal and galvanized steel hand rail systems is that their assembly is of a permanent nature. That is, once the rail structure is assembled, the rail is permanently fixed at that location in that configuration.  
           [0006]    There is a need for fence or barrier assemblies to support a panel, such as a sheet of glass, perforated metal, or steel mesh. Such an assembly can be used to protect equipment, prevent personnel from falling through an opening or over a ledge, and to block passage of unwanted materials or objects. U.S. Pat. No. 6,138,993 to Mitchell, Jr. et al. shows a protection screen that includes a plurality of screen panels and is self-supporting. This screen has limited utility, lacks a heavy-duty steel support frame surrounding the panel, does not provide for interchange of panels, and does not have a sheathing or covering to protect a support frame. U.S. Pat. No. 5,967,214 to Berretta discloses a barrier with a tubular frame and an extruded sheet-like element shaped into a closed loop that may be fitted over the tubular frame. This barrier also has limited utility, is not adjustably configurable, and lacks sheathing on the tubular members. The panels also are shrink-fit to the frame making interchangeability difficult. U.S. Pat. No. 5,967,089 to Alan discloses a lightweight, collapsible, hinged fencing structure that includes multiple rectangular panels that are hingedly interconnected. Each panel consists of a plastic tubular frame with a lightweight polymeric sheet supported by the frame. This structure again has a limited utility and is not flexibly configurable. The plastic frame also lacks the requisite strength for application where a steel frame is required. U.S. Pat. No. 4,841,967 to Hogg et al. discloses a glass panel mounting assembly that forms a glass barrier with a rail at the top edge. The glass panel forms a decorative barrier that lacks the requisite strengths for many applications. It is not flexibly configurable, and lacks a steel surrounding frame. In light of the above, there remains a need for a barrier assembly that is adjustably configurable, has steel frame members interconnected with one another, and a plastic sheathing over the rails, and supports a panel.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention provides a knock-down hand rail assembly that is formed of both metal and plastic. The hand rail assembly is readily and easily assembled and disassembled. The hand rail is maintenance free and requires no paint or other upkeep.  
           [0008]    The assembly of the present invention can be used in many applications both indoor and out. The hand rail assembly can readily be assembled anywhere. The assembly can also readily be disassembled to form a different hand rail structure configuration or to add more rails to the structure. Further, the hand rail can be readily disassembled to change the plastic for the purpose of changing colors of the rail or adding/subtracting signage provided on the structure. This is advantageous when using the invention in an auditorium setting. The ability to color code railings with seating makes it easier on attendees to find their seats during a game or show. The knock down hand rail assembly of the present invention includes at least two spaced apart vertical rails and at least two base supports for supporting the vertical rails in an upright position. Alternatively, the vertical rails may be supported by the ground using standard coring procedures. At least two spaced apart horizontal rails are provided and removably engaged with the vertical rails. These horizontal rails are preferably positioned above the base supports. Each vertical and horizontal rail is surrounded by removable and replaceable polymerized sheathing. The polymerized sheathing has an interior diameter equal to or greater than the outer diameter of each rail. Slip-on structural fittings are provided to removably engage the horizontal rails to the vertical rails. In other preferred embodiments, a plurality of vertical and horizontal rails surrounded by polymerized sheathing and engaged by slip-on structural fittings can be used.  
           [0009]    In yet other preferred embodiments of the present invention, vertical and horizontal posts or rails form a perimeter frame and define a framed area. An infill panel is supported in the framed area. The infill panel may be a sheet of glass or polymer, steel mesh, or perforated steel. In some versions, slip-on structural fittings engage and removably interconnect the horizontal and vertical rails. Clips or brackets interconnect to the infill panel with the vertical and horizontal rails. In other embodiments, slip-in structural fittings are provided that have one end that engages the inner diameter of a horizontal or vertical rail, and another end that mounts to the side of another rail. These and other objects, advantages and features of this invention will become apparent upon review of the following specification in conjunction with the drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a perspective view of the hand rail assembly of the present invention;  
         [0011]    [0011]FIG. 2 is an exploded view of a preferred embodiment of the hand rail assembly of the present invention;  
         [0012]    [0012]FIG. 3 is a cross-sectional view taken along line  3 - 3  of FIG. 1;  
         [0013]    [0013]FIG. 4 is a perspective view of a second preferred embodiment of the hand rail assembly of the present invention;  
         [0014]    [0014]FIG. 5 illustrates, from an oblique perspective, an alternative embodiment of the invention including a mesh infill;  
         [0015]    [0015]FIG. 6 is a close-up detail of the corner of the assembly of FIG. 5;  
         [0016]    [0016]FIG. 7 illustrates an alternative way of forming U-channels according to the invention to ensure that there are no gaps in the infill;  
         [0017]    [0017]FIG. 8 illustrates the use of clips as opposed to full-length channels, and an alternative corner gap-filling corner configuration;  
         [0018]    [0018]FIG. 9 is a perspective view of another preferred embodiment of a barrier assembly with an infill panel according to the present invention;  
         [0019]    [0019]FIG. 10 is an end view of the barrier assembly of FIG. 9;  
         [0020]    [0020]FIG. 11 is a front elevational view of the barrier assembly of FIG. 9;  
         [0021]    [0021]FIG. 12 is a top plan view of the barrier assembly of FIG. 9;  
         [0022]    [0022]FIG. 13 is a bottom plan view of the barrier assembly of FIG. 9;  
         [0023]    [0023]FIG. 14 is a perspective view of another embodiment of a barrier assembly with an infill panel according to the present invention, utilizing an alternative slip-in structural fitting;  
         [0024]    [0024]FIG. 15 is an end view of the barrier assembly of FIG. 14;  
         [0025]    [0025]FIG. 16 is a front elevational view of the barrier assembly of FIG. 14;  
         [0026]    [0026]FIG. 17 is top plan view of the barrier assembly of FIG. 14;  
         [0027]    [0027]FIG. 18 is a bottom plan view of the barrier assembly of FIG. 14;  
         [0028]    [0028]FIG. 19 is a detailed end view of one embodiment of a clip for holding an infill panel for a barrier assembly according the present invention;  
         [0029]    [0029]FIG. 20 is a detailed perspective view of a slip-in structural fitting interconnecting a horizontal and vertical rail;  
         [0030]    [0030]FIG. 21 is a detailed perspective view of another slip-in structural fitting interconnecting a horizontal and vertical rail, along with an end cap closing the end of a horizontal rail;  
         [0031]    [0031]FIG. 22 is an exploded perspective view of a portion of a horizontal and vertical rail along with a slip-in structural fitting; and  
         [0032]    [0032]FIG. 23 is a detailed view of an alternative embodiment of a slip-in structural fitting. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]    With reference to FIGS. 1 and 2, a knock down hand rail system  10  is thereshown. In this first preferred embodiment, at least two spaced apart vertical rails  12 ,  14  are provided and supported in an upright position by base supports  16 ,  18 . These base supports  16 ,  18  provide removable and replaceable support with the ground  20  and are preferably secured to the ground  20  by bolts  22 . Alternatively, the hand rail assembly can be cored to the ground for support.  
         [0034]    The hand rail assembly of the present invention also includes at least two spaced apart horizontal rails  24 ,  26  removably engaged with vertical rails  12 ,  14  and positioned above base supports  16 ,  18 .  
         [0035]    As shown in FIG. 2, vertical rails  12 ,  14  are surrounded by removable and replaceable polymerized sheathing  28 ,  30 . This sheathing  28 ,  30  preferably slip fits about vertical rails  12 ,  14  and has an interior diameter equal to or greater than the exterior diameter of vertical rails  12 ,  14 . This aspect of the invention will be described in greater detail below.  
         [0036]    As with vertical rails  12 ,  14 , corresponding horizontal rails  24 ,  26  are also surrounded by polymerized sheathing  32 ,  34  respectively. Additionally, this polymerized sheathing has an interior diameter that is equal to or greater than the exterior diameter of horizontal rails  24 ,  26 . As stated above, this slip fit of the polymerized sheathing  32 ,  34  about horizontal rails  24 ,  26  will be described in detail later.  
         [0037]    Slip-on structural fittings  36 ,  40  are provided to removably engage horizontal rails  24 ,  26  to each other and to vertical rails  12 ,  14 . These slip-on structural fittings are preferably Hollaender structural fittings manufactured by The Hollaender Manufacturing Company, Cincinnati, Ohio. T-shaped slip-on structural fitting  36  may be provided to join horizontal rail  24  to horizontal rail  26  and include an extra opening for additional vertical rails if desired. T-shaped slip-on structural fitting  36  removably engages horizontal rails  24 ,  26  and polymerized sheathing  32 ,  34  by set screws  38 .  
         [0038]    L-shaped Hollaender slip-on structural fittings  40  removably engage horizontal rails  24 ,  26  to vertical rails  12 ,  14 . L-shaped slip-on structural fittings  40  removably secure the rails to each other by set screws  42 .  
         [0039]    With reference to FIG. 3, each slip-on structural fitting provided to removably secure the knockdown hand rail system  10  of the present invention typically includes a structural fitting  40  for securing horizontal rail  24  with polymerized sheathing  32  to vertical rail  14  with polymerized sheathing  30 . More specifically, interior diameter  44  of polymerized sheathing  32  is equal to or greater than exterior diameter  46  of horizontal rail  24 . Additionally, interior diameter  48  of L-shaped slip-on fitting  40  is equal to or greater than the exterior diameter  50  of polymerized sheathing  32 . Set screw  42  is preferably a counter bore knurled cup point set screw that securely fastens L-shape slip-on fitting  40  through polymerized sheathing  32  onto horizontal rail  24 . This structural assembly is typical of all rails, polymerized sheathing, and slip-on fittings of the present invention.  
         [0040]    In a second preferred embodiment of the present invention, a third vertical rail  52  may be provided therewith. Vertical rail  52  is also preferably surrounded by polymerized sheathing  54  having an interior diameter equal to or greater than the exterior diameter of vertical rail  52 . Vertical rail  52  is typically provided with base support  56  for supporting vertical rail  52  in an upright position. Base support  56  may be secured to the ground  20  by bolts  22  as typically shown in base supports  16 ,  18 .  
         [0041]    Vertical rail  52  with polymerized sheathing  54  may be provided with a cross-shaped slip-on structural fitting  70  for supporting additional horizontal rails  58 ,  60 . These horizontal rails  58 ,  60  are also preferably surrounded by polymerized sheathing  62 ,  64  respectively. As with all polymerized sheathing of the present invention, polymerized sheathing  62 ,  64  has an interior diameter equal to or greater than the exterior diameter of horizontal rails  58 ,  60 . Cross-shaped slip-on structural fitting  70  removably secures horizontal rails  58 ,  60  with polymerized sheathing  62 ,  64  to third vertical rail  52  with polymerized sheathing  54  by set screws  72 . Horizontal rails  58 ,  60  with polymerized sheathing  62 ,  64  are secured to vertical rails  12 ,  14  with polymerized sheathing  28 ,  30  by T-shaped slip-on structural fittings  66  with set screws  68 .  
         [0042]    Proper assembly of the preferred present invention is as follows. Vertical rails  12 ,  14 ,  52  are spaced apart and supported in an upright position by base supports  16 ,  18 ,  56 . These base supports are removably secured to the ground  20  by any mechanical means such as bolts  22 . Removable and replaceable polymerized sheathing  28 ,  30 ,  54  is preferably slip-fit about corresponding vertical rails  12 ,  14 ,  52 . T-shaped slip-on structural fittings  66  are slipped over polymerized sheathing  28 ,  30  to be secured and positioned later.  
         [0043]    Horizontal rails  24 ,  26  are provided therewith and surrounded by corresponding polymerized sheathing  32 ,  34 . One end of each horizontal rail is secured to L-shaped slip-on fitting  40  by a corresponding set screw  42 . The opposite end of horizontal rails  24 ,  26  with corresponding polymerized sheathing  32 ,  34  is secured to a T-shaped slip-on fitting  36  by corresponding set screws  38 . The entire removably secured structure of these horizontal rails is then placed atop corresponding vertical rails  12 ,  14 ,  52  with polymerized sheathing  28 ,  30 ,  54  respectively. Remaining set screws  38 ,  42  removably attach the horizontal rail structure to the vertical rail structure. Lastly, horizontal rails  58 ,  60  are surrounded by polymerized sheathing  62 ,  64  respectively. Each horizontal rail  58 ,  60  with corresponding polymerized sheathing  62 ,  64  are removably secured between vertical rails  12 ,  14 ,  52  with corresponding polymerized sheathing  28 ,  30 ,  54  by slip-on structural fittings  66 ,  70 . Set screws  68 ,  72  removably engage these additional horizontal rails to the vertical rails at any point along the vertical rails.  
         [0044]    An alternative embodiment of the present invention involves extension and bending of vertical rails  28 ,  30  to form horizontal rail  34 , as shown in FIG. 4. That is, inner frame vertical rail  12 ,  14  is slip-fit into corresponding polymerized sheathing  28 ,  30  and is then bent to create a rounded corner and thereby extend into a horizontal rail. In this way, Hollaender fittings  40  would be eliminated and horizontal rails  24 ,  26  with corresponding polymerized sheathing  32 ,  34  would be replaced by extended vertical rails  12 ,  14  with polymerized sheathing  28 ,  30  to meet at Hollaender fittings  36 . In an extended version of this preferred embodiment, Hollaender fitting  36  may be provided to simply support vertical rail  52  with polymerized sheathing  54  to the singularly extended vertical rail  12  with corresponding sheathing  28 . In this embodiment, vertical rail  12  would then extend to form both exterior vertical rails  12 ,  14  and horizontal rails  24 ,  26 . A singular unit of polymerized sheathing would also extend about the singular rail and be bent to form rounded corners at the upper edges.  
         [0045]    Alternative embodiments of the present invention may involve the use of only one top horizontal rail or several horizontal and vertical rails extending to create an elongated hand rail assembly  10 . It was envisioned that each vertical rail will be removably supported to the ground by a base or structure if necessary. Additional base structures are also shown in FIG. 4. Moreover, each additional horizontal rail is preferably supported to the vertical rails by Hollaender slip-on structural fittings conforming to any shape necessary to create the overall structural shape of the hand rail assembly of the present invention. That is, the hand rail of the present invention may extend linearly, triangularly, circularly, or any other shape that may reasonably be configured. Moreover, each rail, vertical and horizontal, shall preferably be surrounded by polymerized sheathing having an interior diameter that is equal to or greater than the exterior diameter of the corresponding rail.  
         [0046]    [0046]FIG. 5 illustrates, from a perspective view, an alternative embodiment of the invention generally at  102  including an infill disposed between the horizontal and vertical sheathing-covered rails  30  and  34 . Although the embodiment depicted in FIGS. 5 and 6 illustrate the use of a mesh panel  106  received by continuous channels  104 , it is readily apparent that the arrangement is conducive to the use of other types of infills, including clear and opaque plastics, glass, and meshes and perforated sheets having apertures of any scale, depending upon the application.  
         [0047]    [0047]FIG. 6 is a close-up view of the way in which the channels  104  attach to the rails  30  and  34 , and the way in which infill  106  is received thereby. Preferably, a plurality of spaced-apart self-tapping fasteners  105  are used to adhere the U-channels  104  to the members as shown. Since the fasteners  105  must go through the U-channel material, sheathing and wall of the associated rail, it may be advisable to predrill holes for each fastener, as the case may be. Although the material used for the infill may not include a finished edge, particularly when mesh panels are used, it is preferable to have a peripheral seam  108  to provide a more finished look. In terms of materials, the U-channels  104  are preferably constructed of some type of corrosion-resistant metal such as aluminum, though other types of metals and even non-metals may be used, so long as they are of sufficient strength and durability.  
         [0048]    To fill the triangular gap which would otherwise be left due to the difference in height between the sheath covered rails and corner/T-assemblies  40  and  46 , a configuration such as that depicted in FIG. 7 may alternatively be utilized. In this case, the U-channels  112  include relieved areas  114  such that, when assembled, a cleaner full corner appearance is achieved. In such a case, an infill having a square corner may be used, such as mesh screen  120  having a finished squared-off corner  122 .  
         [0049]    [0049]FIG. 8 illustrates certain additional alternative configurations according to the invention, which may be used independently or in combination with other arrangements described herein. For example, in place of a continuous U-channel, clips  140  may alternatively be used, particularly if the edge of the infill is peripherally finished or otherwise continuous. As a further option, the edge of the infill may be scalloped, as shown at  150 . With such a shaped configuration, which may be used with clips or a continuous U-channel, the triangularly shaped gap shown in FIGS. 5 and 6 would be filled without having to grind or otherwise modify the U-channel or clip members.  
         [0050]    Referring now to FIGS.  9 - 13 , an additional embodiment of a knock down hand rail system according to the present invention is generally shown at  200 . The hand rail system has a pair of spaced apart vertical rails  202  and  204 , each covered with a polymerized sheathing, as previously described. An upper rail  206  extends horizontally between the upper ends of the vertical posts  202  and  204  and is also covered with a removable and replaceable polymerized sheathing. Slip-on structural fittings  208  and  210  interconnect the ends of the upper rail  206  with the upper ends of the vertical posts  202  and  204 , respectively. A lower rail  212  extends horizontally between the vertical posts  202  and  204  and is covered with a polymerized sheathing. It is interconnected at its ends with the vertical posts  202  and  204  using T-shaped slip-on structural fittings  214  and  216 , respectively. The T-shaped fittings  214  and  216  may be moved upwardly and downwardly so as to change the spacing between the lower rail  212  and the upper rail  206 . Though not shown, the structural fittings  208 ,  210 ,  214 ,  216  preferably includes screws or bolts that allow the fittings to grip the vertical and horizontal rails to which they connect. Preferably, the screws or bolts do not penetrate the polymerized sheathing or the rails or posts.  
         [0051]    The vertical posts  202  and  204  and the upper and lower rails  206  and  212  together define a perimeter frame with a framed area  218  defined therein. The framed area has a top edge defined by the upper rail  206 , a lower edge defined by the lower rail  212 , and sides defined by the vertical post  202  and  204 . An infill member or panel  220  is supported in the framed area. As previously discussed, the infill member or panel  220  may be any of a variety of materials including a glass, polymer, or perforated steel or plastic sheet, or a steel or fiberglass mesh. In the embodiment illustrated in FIG. 9, the panel  220  is a piece of steel or plastic with perforations. The panel  220  is supported in the framed area by a variety of clips  222 . Each clip  222  grips an edge of the panel  220  and interconnects with one of the posts or rails. The illustrated infill panel  220  may be eliminated in some applications, with the vertical posts and horizontal rails acting as a hand rail.  
         [0052]    In the illustrated embodiment, the lower ends of the vertical posts  202  and  204  extend downwardly below the underside of the lower rail  212 . This design is configured so that the lower ends of the vertical post  202  and  204  fit into holes in a support surface. Alternatively, support members may be attached to the lower ends of the vertical posts  202  and  204 .  
         [0053]    Referring now to FIGS.  14 - 18 , another embodiment of a knock down hand rail system with an infill panel according to the present invention is generally shown at  230 . The hand rail system  230  is similar to the previous embodiments, and includes a pair of vertical posts  232  and  234 , an upper rail  236  extending between the upper ends of the vertical post  232  and  234 , and a lower rail  238  positioned below the upper rail  236  and also extending between the vertical posts  232  and  234 . This embodiment differs from the prior embodiment in that the infill panel  240  is a sheet of glass or plastic, support members  242  and  245  engage the lower ends of the vertical post  232  and  234 , respectively, and, most importantly, a different type of structural fitting is used to interconnect the rails and posts.  
         [0054]    As with the previous embodiment, clips  246  interconnect the infill panel  240  with the rails and posts. FIG. 19 shows an end view of a clip  246 . A clip  246  in FIG. 19 is oriented as are the clips that interconnect the infill panel with the upper rail  236  in FIG. 14. In this orientation, the clip  246  has an upper end  248  that is radiused so as to mate with the outer radius of the polymerized sheathing surrounding the upper rail  236 . A bolt or screw, not shown passes through a bore  250  in the upper end and engages the upper rail  236 . The lower end  252  of the clip has a slot-like opening  254  that accepts the edge of the infill panel  240 . The width of the slot  254  depends on the thickness of the panel  240 . Alternatively, the clip may be made adjustable to accommodate variations in thickness of infill panels, or the slot  254  may be lined to improve the engagement between the clip and panel. For example, a glass panel may require a rubberized lining in the clips to avoid chipping the edges of the glass.  
         [0055]    Referring now to FIGS.  20 - 23 , the alternative structural fitting used with the hand rail system of FIGS.  14 - 18  will be described in more detail. FIG. 20 is a detailed view of one of the lower comers of the hand rail system of FIG. 14 showing the support member  242  supporting the lower end of vertical post  232  which extends upwardly from the support member  242 . The horizontal lower rail  238  is interconnected with the vertical post  232  just above the support member  242  using a structural fitting  260 . The structural fitting  260  differs from the previous slip-on structural fitting in that it is a much more flush design.  
         [0056]    [0056]FIG. 22 shows an exploded view of an interconnection similar to that of FIG. 20. A portion of vertical post  232  is shown with structural fitting  260  engaged to its side. The structural fittings may be oriented in various positions. However, for ease of description, the fitting  260  will be described in the orientation illustrated, with such terms as left and right being arbitrary. The fitting  260  has a base  262  at its left end and engagement members  264  at its right end. The base  262  has an end surface that is radiused so as to mate with the outer surface of the sheathing covering the vertical post  232 . A bore, not shown, passes through the base  262 . A bolt or screw  268  passes through this bore and engages the vertical post  232 . The bolt or screw  268  may be self-threading, or may require that a hole be drilled and/or tapped in the post  232 . The bolt  268  engages the hole in the post  232  and brings the radiused end surface  266  of the base  262  into firm contact with the side of the post  232 . Engagement members  264  extend rightwardly out of the base  262 . The engagement members  264  include a pair of engagement fingers  270  and  272 . Each finger  270  and  272  has a semi-arcuate outer profile configured to engage the interior diameter of the lower rail  238 . As illustrated, the rail  238  has an inner steel rail  274  and a polymerized sheathing  276  surrounding the rail  274 . The steel rail  274  has an inner diameter. The fingers  270  and  272  engage this inner diameter. The fingers  270  and  272  may be tapered or shaped so as to be a press fit into the rail  274 , or may slide easily thereinto. A bolt or screw  278  interconnects the lower rail  238  with the fingers  270  and  272 . In one embodiment, a hole  280  is provided in the lower finger  270 . The lower rail  238  is slid onto the fingers  270  and  272 . A hole is then drilled through the combination of the rail  274  and sheathing  276  so that the screw  278  can engage the hole  280 . Alternatively, the screw may be self-tapping and make its own hole in the sheathing  276 , rail  274 , and/or the finger  270 . The holes may also be pre-drilled in the ends of the rail  238 . For some applications, a screw or bolt may not be required to maintain assembly of the hand rail. A press fit may be sufficient or adhesives may be used to interconnect the rail to the fitting. As another alternative, the screw  278  may engage the hole  280  in the lower finger  270  and, when sufficiently tightened, press against the upper finger  272 , thereby spreading the fingers  270  and  272  apart so as to securely engage the inner diameter of the rail  274 . Referring again to both FIGS. 20 and 22, it can be seen that the base  262  of the fitting  260  has an outer diameter similar to the outer diameter of the sheath  276  of the rail  238  so that, when assembled, the fitting  260  and the lower rail  238  have flush outer diameters giving a very pleasing appearance.  
         [0057]    Referring now to FIG. 21, a detailed view of an upper corner of the hand rail system of FIGS.  14 - 18  is shown. The upper end of one of the vertical posts  234  is shown interconnected with one end of the upper rail  236  using another slip-in structural fitting  290 . The slip-in structural fitting  290  is the same as shown in FIG. 22, though the orientation has been changed. An end cap  292  is also provided that closes the open end of the upper rail  236  where it extends beyond the upper end of the vertical post  234  and the fitting  290 .  
         [0058]    Referring now to FIG. 23, alternative structural fitting  294  is shown. The fitting  294  is again a slip-in fitting, but is designed to form a corner without the need for the end cap  292  shown in FIG. 21. Instead, the fitting  294  has a first pair of fingers  296  extending in a first direction and a second set of fingers  298  extending in a second direction, with the second direction positioned at 90 degrees to the first direction. As will be clear to those of skill in the art, other slip-in structural fittings may be provided, such as T-shaped fittings, or fittings that support any number of structural members at any number of angles. As a further alternative, a T-shaped fitting may be provided with the leg of the T including slip-in fingers while the “top” of the T is a slip-on structural fitting. This combines the benefits of the slip-on and slip-in fittings. It gives a flush appearance between the fitting and a member that extends in one direction, but allows adjustment where the “top” of the T engages another member. Any of these slip-in fittings may be used in any embodiments of the present invention.  
         [0059]    The above description is considered that of the preferred embodiment only. Modifications of the invention may occur to those of ordinary skill in the art. Therefore, it is understood that the embodiments shown in the drawing and described above are merely for illustration purposes and are not intended to limit the scope of the invention.

Summary:
The present invention provides a knockdown hand rail assembly that is formed of both metal and plastic. The hand rail assembly is readily and easily assembled and disassembled. The hand rail assembly is maintenance free and requires no paint or other upkeep. The assembly can be used in many applications both indoor and out. The hand rail assembly includes at least two spaced apart vertical posts and at least two spaced apart horizontal rails removably engaged with the vertical posts. Each rail and post is surrounded by removable and replaceable polymerized sheathing having an interior diameter equal to or greater than the outer diameter of the post or rail. Removable structural fittings interconnect the rails and posts.