Patent Publication Number: US-8122674-B2

Title: Grating system forvehicular and pedestrian traffic

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates generally to grates and grating systems. More particularly, the invention relates to a grating assembly which may accommodate vehicle traffic and pedestrian traffic. 
     2. Background Information 
     There have been various improvements in grating assemblies which are configured for supporting vehicle traffic while also conveniently accommodating pedestrian traffic. For instance, these grating assemblies are configured with spacing along the upper surface which is appropriate for accommodating wheelchairs without the risk of the wheels thereof becoming stuck, and also for accommodating walking canes and the spikes of high heeled shoes without the canes or spikes becoming stuck and thus presenting an injury problem. U.S. Pat. No. 7,121,759 granted to Woodson et al. provides such a grating assembly. However, one of the drawbacks to the Woodson configuration is the use of welds on the upper surface of the grating assembly which detracts from its aesthetic appeal. 
     The prior art also includes gratings which are used particularly to form bridge decks. For instance, U.S. Pat. No. 6,049,932 granted to Mangone discloses weld-free grids or gratings for bridge decks where the grating is typically filled with concrete and thus serves as a reinforcing structure with the concrete extending above the upper surface of the grating. Although the Mangone reference may utilize minor welding, it is configured primarily to eliminate or substantially eliminate welds between its various bars. One key aspect of the Mangone reference is the use of notches in some of its bars in order to provide an interlocking configuration at the intersections of certain bars. For instance, Mangone discloses primary load-bearing members having rectangular through openings formed therein for receiving a secondary load-bearing member therethrough wherein the secondary member includes downwardly opening bottom notches or slots which are aligned with the portions of the primary members which bound the bottom of the through openings therethrough so that the bottom slots receive therein this portion of the load-bearing member. While Mangone indicates that this configuration locks the two members in position, this configuration is less than desirable for use with a grating assembly which is intended to be used on its own without concrete inasmuch as such a locking configuration without the use of concrete or welding would tend to become loose over time especially under regular traffic traveling over the grating assembly. The present invention addresses these and other problems in the art. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a grating system having longitudinal and axial directions comprising: a plurality of axially spaced longitudinal deep bars each having top and bottom surfaces; a first set of aligned through slots formed in the deep bars; a second set of aligned through slots formed in the deep bars and longitudinally spaced from the first set of slots; a first set of aligned deep bar through holes formed in the deep bars upwardly of the first set of slots; a second set of aligned deep bar through holes formed in the deep bars upwardly of the second set of slots; a first axial crossbar slidably inserted lengthwise into the first set of slots; a second axial crossbar slidably inserted lengthwise into the second set of slots; a plurality of longitudinal filler bars seated on the crossbars between the deep bars and having respective top surfaces which are substantially flush with the top surfaces of the deep bars; a first set of aligned filler bar through holes formed in the filler bars and aligned with the first set of deep bar holes; a second set of aligned filler bar through holes formed in the filler bars and aligned with the second set of deep bar holes; a first axial joining bar slidably inserted lengthwise into the first set of deep bar holes and first set of filler bar holes; a second axial joining bar slidably inserted lengthwise into the second set of deep bar holes and second set of filler bar holes; and wherein each crossbar has joined and unjoined positions in which it is respectively separate from and joined to the deep bars; and each crossbar is slidably inserted lengthwise into the respective set of slots along a linear path to move from the unjoined position to the joined position such that the linear slidable insertion alone substantially fixes the position of the respective crossbar in the vertical and longitudinal directions relative to the deep bars. 
     The present invention also provides a grating system having longitudinal and axial directions comprising: a plurality of axially spaced longitudinal deep bars each having top and bottom surfaces; a first set of aligned through slots formed in the deep bars; a second set of aligned through slots formed in the deep bars and longitudinally spaced from the first set of slots; a first set of aligned deep bar through holes formed in the deep bars upwardly of the first set of slots; a second set of aligned deep bar through holes formed in the deep bars upwardly of the second set of slots; a first axial crossbar slidably inserted lengthwise into the first set of slots; a second axial crossbar slidably inserted lengthwise into the second set of slots; a plurality of longitudinal filler bars seated on the crossbars between the deep bars and having respective top surfaces which are substantially flush with the top surfaces of the deep bars; a first set of aligned filler bar through holes formed in the filler bars and aligned with the first set of deep bar holes; a second set of aligned filler bar through holes formed in the filler bars and aligned with the second set of deep bar holes; a first axial joining bar slidably inserted lengthwise into the first set of deep bar holes and first set of filler bar holes; a second axial joining bar slidably inserted lengthwise into the second set of deep bar holes and second set of filler bar holes; and wherein the crossbars have top and bottom surfaces; and the crossbars are free of bottom notches which extend upwardly from their respective bottom surfaces and receive therein respective portions of the deep bars to interlock the crossbars and deep bars to one another. 
     The present invention further provides a grating system having longitudinal and axial directions comprising; a plurality of axially spaced longitudinal deep bars each having top and bottom surfaces; a first set of aligned through slots formed in the deep bars; a second set of aligned through slots formed in the deep bars and longitudinally spaced from the first set of slots; a first set of aligned deep bar through holes formed in the deep bars upwardly of the first set of slots; a second set of aligned deep bar through holes formed in the deep bars upwardly of the second set of slots; a first axial crossbar slidably inserted lengthwise into the first set of slots; a second axial crossbar slidably inserted lengthwise into the second set of slots; a plurality of longitudinal filler bars seated on the crossbars between the deep bars and having respective top surfaces which are substantially flush with the top surfaces of the deep bars; a first set of aligned filler bar through holes formed in the filler bars and aligned with the first set of deep bar holes; a second set of aligned filler bar through holes formed in the filler bars and aligned with the second set of deep bar holes; a first axial joining bar slidably inserted lengthwise into the first set of deep bar holes and first set of filler bar holes; a second axial joining bar slidably inserted lengthwise into the second set of deep bar holes and second set of filler bar holes; wherein the deep bars and crossbars intersect one another at respective intersections; and a plurality of welds securing the deep bars and crossbars to one another at a majority of the intersections. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       A preferred embodiment of the invention, illustrated of the best mode in which Applicant contemplates applying the principles, is set forth in the following description and is shown in the drawings and is particularly and distinctly pointed out and set forth in the appended claims. 
         FIG. 1  is a perspective view of the grating system of the present invention as it would appear installed in the ground. 
         FIG. 2  is a perspective view of the base structural framework of the grating assembly which primarily is formed of multiple deep bars. 
         FIG. 3  is an enlarged perspective view of a portion of  FIG. 2  illustrating the insertion of the crossbars through the slots in the deep bars. 
         FIG. 4  is similar to  FIG. 3  and shows the filler bars prior to being lowered onto the crossbars. 
         FIG. 5  is similar to  FIG. 4  and shows the insertion of the joining bars through the holes in the deep bars and the filler bars. 
         FIG. 6  is similar to  FIG. 5  and shows the grating assembly after the crimping of the joining bars. 
         FIG. 7  is a sectional view taken on line  7 - 7  of  FIG. 1 . 
         FIG. 8  is a sectional view taken on line  8 - 8  of  FIG. 1 . 
         FIG. 9  is a top plan view of a portion of the grating assembly adjacent one of its corners. 
     
    
    
     Similar numbers refer to similar parts throughout the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The grating system of the present invention is shown generally at  10  in  FIG. 1  installed on a supporting structure  12  which may include a bed of concrete or the like in which grating system  10  is embedded. Grating assembly or system  10  is mostly typically formed of metal and has a top or upper surface  14  which is substantially flush with or at the same height of an upper surface  16  of supporting structure  12 . System  10  also has a bottom or lower surface  15  ( FIG. 2 ). System  10  has first and second ends  18  and  20  defining therebetween a longitudinal direction of the system, and first and second opposed sides  22  and  24  defining therebetween an axial direction of the system. Although system  10  is shown  FIG. 1  as imbedded in the ground, it may also be used to form an overhead walkway or bridge whereby the openings defined between its various components allow a person to see objects therebelow as they walk or ride across the bridge in a vehicle. Upper surface  14  of system  10  is thus intended to be a contact surface which is contacted by a pedestrian or the wheels of a wheelchair or other vehicle during travel over the grating assembly. System  10  is thus configured as a see-through grating assembly which stands on its own as opposed to being used as a reinforcement structure for concrete or the like. System  10  is thus ordinarily free of concrete disposed within the spaces defined between its various bars, which are described in greater detail below. 
     With reference to  FIG. 2 , system  10  includes a rigid primary framework or grating subassembly  26  primarily comprising a plurality of straight longitudinal deep bars  28  which are typically axially evenly spaced from one another and rigidly mounted within a perimeter wall  30  which includes first and second opposed typically parallel axial end bars  32  and  34 , and first and second typically parallel longitudinal side bars  36  and  38  which extend perpendicularly between and are rigidly connected to end bars  32  and  34  to form respective corners in system  10 . Side bars  36  and  38  are deep bars  28  that also serve as the respective ends of subassembly  26  and form part of perimeter wall  30 . Deep bars  28  and end bars  32  and  34  are formed of a rigid material which is most typically a metal. Each deep bar  28  has first and second opposed ends  40  and  42  which are respectively rigidly secured to inner surfaces of first and second end bars  32  and  34 , typically by respective welds  44  ( FIGS. 2 ,  3  and  9 ). Each deep bar  28  is in the exemplary embodiment a vertically oriented plate of metal having an uppermost or top surface or edge  46  and a lowermost or bottom surface or edge  48 . Edges  46  and  48  are straight, parallel and continuous from end to end. Edges  46  and  48  define therebetween a height H 1  ( FIG. 7 ) which represents the height of deep bars  28 , side bars  36  and  38  and end bars  32  and  34 . Height H 1  in the exemplary embodiment is about 3.5 inches and typically within the range of about 2 to 8 inches. In the exemplary embodiment, the tops and bottoms of the respective deep bars, end bars  32  and  34  and side bars  36  and  38  are respectively at the same height as one another. Deep bar  28  has flat vertical first and second opposed sides  50  and  52  defining therebetween a thickness thereof which in the exemplary embodiment is about 3/16 inch and typically is within the range of about ⅛ to ½ inch. Inasmuch as side bars  36  and  38  have the same configuration as the other deep bars  28 , the numerical indicators  46 ,  48 ,  50  and  52  likewise represent the top, bottom and opposed sides respectively of said side bars. Each adjacent pair of deep bars  28  is axially spaced from one another so that the centers thereof define therebetween a distance D 1  which is typically on the order of about four inches although this may vary depending on loading requirements. A plurality of longitudinally spaced crossbar-receiving vertical through openings or slots  54 A-C is formed in each deep bar extending from first side  50  to second side  52 . The slots  54 A in the various deep bars are aligned along a straight horizontal axial line which is perpendicular to deep bars  28  and parallel to end bars  32  and  34  whereby the slots  54 A together form a first set of slots, the aligned slots  54 B together form a second set of slots, and slots  54 C together form a third set of slots. Additional sets of slots like slots  54  may be formed depending on the spacing between each set and the length of deep bars used. Each slot  54  in the exemplary embodiment is in the form of a vertically elongated rectangle. Slots  54  are spaced upwardly from bottom surface  48  so that they do not communicate therewith. A plurality of longitudinally spaced through holes  56 A-C is also formed in each deep bar from side  50  to side  52  such that holes  56 A-C are formed directly above slots  54 A-C respectively. Each of holes  56  is spaced upwardly of the respective slot  54  and downwardly of the upper or top surface  46  of the corresponding deep bar. Thus, each of slots  54  and holes  56  are spaced downwardly of top surface  46  so that none of said slots or holes communicates with the top surface  46  nor the top surface  14  of system  10  inasmuch as top surfaces  46  form a part of top surface  14 . The holes  56 A formed in the deep bars together form a first set of holes while holes  56 B together form a second set of holes and holes  56 C form a third set of holes so that the holes in each set are aligned along a straight horizontal axial line which is perpendicular to deep bars  28  and parallel to end bars  32  and  34 . Each adjacent set of slots  54  measured from center to center defines therebetween a distance D 2  which is the same as the distance between each adjacent set of holes  56  as measured from center to center. Each set of holes  58  is thus aligned directly above the corresponding set of slots  54 . 
     With primary reference to  FIGS. 3 and 4 , system  10  further includes a plurality of longitudinally spaced straight axial crossbars  58  having first and second opposed ends  60  and  62  ( FIG. 7 ) defining therebetween an axial length of crossbar  58  which is substantially the same as the length defined between the outer surface of first side bar  36  and the outer surface of second side bar  38 . Each cross bar  58  has an uppermost or top edge  64  and a bottom or lowermost surface or edge  66  defining therebetween a height H 2  ( FIG. 7 ) which is slightly less than the height of each slot  54 . Height H 2  is in the exemplary embodiment about ½ inch and typically within the range of about ½ to 1.0 inch. Edges  64  and  66  are straight, parallel and continuous from end to end. Crossbar  58  has first and second opposed vertical sides  68  and  70  defining therebetween a thickness which is slightly less than the width of each slot  54 . The thickness of each crossbar  58  is in the exemplary embodiment about ⅛ inch and typically within the range of about ⅛ to 3/16 inch. The shape of each slot  54  and the cross sectional shape of each crossbar  58  is typically substantially the same except that the size of the cross sectional dimensions of the crossbar are slightly smaller than that of the slot. Each set of slots  54  is thus configured to slidably receive therein a respective one of crossbars  58  as it moves from an unjoined position separate from deep bars  28  horizontally and linearly in the axial direction perpendicular to deep bars  28  as illustrated by arrows A 1  and A 2  in  FIG. 3 , with Arrow A 1  corresponding to one crossbar  58  already slid lengthwise into a joined position and Arrow A 2  corresponding to another crossbar  58  in its unjoined position prior to insertion into slots  54 A. Slots  54  and crossbars  58  are configured so that the insertion of crossbar  58  into a corresponding set of slots  54  to reach its final joined position within system  10  requires only this horizontal and linear sliding movement of the given crossbar. This is in accordance with the slots  54  having height and width dimensions which are only slightly greater than the cross sectional shape of the crossbar  58  such that each crossbar  58  upon its linear insertion is in its joined position substantially fixed relative to the deep bars  28  in the vertical direction as well as in the horizontal longitudinal direction of system  10  parallel to deep bars  28 . The configuration of crossbars  58  and slots  54  also substantially prevents each crossbar from rotating about its longitudinal axis (which extends in the axial direction of system  10 ). Thus, each crossbar  58  is free of notches formed therein which would align with any portion of deep bars  28  which bound slots  54  whereby a crossbar  58  could be moved vertically up or down or horizontally in a longitudinal direction or rotated about its longitudinal axis in order that a portion of a deep bar was received in such a notch formed in the crossbar. Preferably, each crossbar is free of notches or other openings formed therein which extend from one side to the other. 
     Arrow A 1  represents one of crossbars  58  having slid all the way into its final position with its first end  60  adjacent and generally flush with the outer surface of first side bar  36  and its second end  62  ( FIG. 7 ) adjacent and typically substantially flush with the outer surface of side bar  38 . Preferably, no portion of crossbar  58  extends outwardly beyond the outer surfaces of first and second side bars  36  and  38 . Arrow A 2  in  FIG. 3  represents the movement of another crossbar  58  toward the set of slots  54 A for insertion therein.  FIG. 4  shows that crossbars  58  after their insertion into the respective set of slots  54  are rigidly secured to deep bars  28  by welds  71  therebetween. Typically, welds  71  are formed at a majority of the intersections between crossbars  58  and deep bars  28  and usually at all or substantially all of these intersections in order to provide a rigid structurally sound framework for mounting the other bars of system  10  thereon. 
     With primary reference to  FIG. 4 , additional structure and assembly of system  10  is described. System  10  further includes multiple axially spaced straight longitudinal filler bars  72  which in the exemplary embodiment are positioned in sets  74  of three filler bars each so that each set  74  when assembled is positioned between a respective adjacent pair of deep bars  28 . Each filler bar  72  has a first end  76  ( FIGS. 1 ,  8 ) and a second end  78  defining therebetween a length which is just slightly shorter than the normal distance between the respective inner surfaces of end bars  32  and  34 . Each filler bar  72  has an uppermost or top surface or edge  80  and a lowermost bottom surface or edge  82  defining therebetween a height H 3  ( FIG. 7 ) which is typically the same as or less than height H 2  of crossbars  58  and thus substantially less than that of deep bars  28 . Height H 2  of crossbars  58  in the exemplary embodiment is typically substantially less than one half that of height H 1  and more typically less than one third of height H 1  and generally on the order of about one quarter or less than height H 1 . Each filler bar  72  has first and second opposed vertical sides  84  and  86  which define therebetween a thickness of filler bar  78 . In the exemplary embodiment, filler bars  72  are formed from the same stock as crossbars  58  such that height H 1  and the thickness of filler bars  78  is the same as that previously noted with regard to crossbars  58 . In the exemplary embodiment, filler bars  72  and deep bars  28  when assembled are evenly spaced from one another as illustrated at distance D 3  in  FIGS. 7 and 9 . More particularly, for each adjacent pair of filler bars  72 , the first side  84  which faces the second side  86  of said adjacent pair defines therebetween distance D 3 . Similarly, the first side  84  of each filler bar  72  which is adjacent and facing second side  52  of an adjacent deep bar  28  defines therebetween distance D 3 , as does the second side  86  of a filler bar which is adjacent and facing first side  50  of an adjacent deep bar  28 . Distance D 3  in the exemplary embodiment is about 5/16 inch and preferably ranges from ¼ to ½ inch. Typically, distance D 7  is no more than ½ inch in order to stay within maximum guidelines of the American With Disabilities Act (ADA). 
       FIGS. 4 and 5  illustrate that each set  74  of filler bars  72  moves downwardly (Arrow B in  FIG. 4 ) from a position above subassembly  26  so that each set  72  is positioned as shown in  FIG. 5  between an adjacent pair of deep bars  28  and so that each filler bar  72  is seated atop crossbars  58  with bottom edges  82  contacting top edges  64 , as best illustrated in  FIGS. 7 and 8 . In keeping with the straight continuous end-to-end top and bottom surfaces of crossbars  58  and filler bars  72 , crossbars  58  are free of upwardly opening notches which communicate with the top surfaces thereof for receiving a portion of filler bars  72  therein, and filler bars  72  are free of downwardly opening notches communicating with lower surfaces thereof for receiving therein respective portions of crossbars  58  when filler bars  72  are lowered into position. Longitudinally spaced circular holes  88 A-C are formed in each filler bar  72 , holes  88 C being illustrated in  FIG. 8 . The holes  88 A formed in the filler bars  72  together form a first set of holes while the corresponding holes  88 B form a second set and the corresponding holes  88 C form another corresponding set of holes. As shown in  FIG. 4 , set  88 A and set  88 B are longitudinally spaced from one another by distance D 2 . As illustrated in  FIG. 8 , set  88 B and set  88 C of holes also spaced from center to center by distance D 2 . Sets  88 A,  88 B and  88 C are thus respectively appropriately spaced from one another so that when filler bars  72  are moved downwardly to the position shown in  FIG. 5 , these sets  88 A-C respectively align with the sets of holes represented by holes  56 A,  56 B and  56 C formed in deep bars  28 . Holes  88  are thus spaced upwardly from slots  54  by the same distance by which holes  56  are spaced upwardly from slots  54  when filler bars  72  are seated atop crossbars  58  as shown in  FIG. 5 . 
     With primary reference to  FIG. 5 , system  10  further includes a plurality of longitudinally spaced straight axial joining bars  90 A-C wherein joining bar  90 C is shown in FIGS.  1  and  7 - 9 . In the exemplary embodiment, each joining bar is a cylindrical hollow tube having first and second ends  92  and  94  ( FIGS. 7 ,  9 ) defining therebetween a length which is substantially the same as that of each crossbar  58 . In the exemplary embodiment, each joining bar  90  is formed of a metal tube having an outer diameter within a range of about 3/16 to 5/16 inch with a wall thickness typically ranging from about 0.028 to about 0.065 inch prior to the crimping or swaging process described further below.  FIG. 5  illustrates filler bar  90 B having been inserted lengthwise (Arrow C 1 ) horizontally and linearly in the axial direction of system  10  through aligned holes  56 B of each deep bar  28  and holes  88 B of each filler bar  72  so that its first end  92  is adjacent and typically flush with the outer surface of side bar  36  and second end  94  ( FIGS. 7 ,  9 ) is adjacent and typically substantially flush with the outer surface of side bar  38 . As with crossbars  58 , preferably no portion of filler bars  72  extend outwardly beyond the outer surfaces of side bars  36  and  38 .  FIG. 5  further shows joining bar  90 A moving toward insertion (Arrow C 2 ) into holes  56 A and  88 A. The horizontal axial insertion of joining bars  90  into the corresponding holes  56  and  88  thus prevents or substantially prevents vertical and longitudinal movement of filler bars  72  with respect to subassembly  26 . This simple horizontal and linear insertion of a given joining bar  90  also prevents or substantially prevents the vertical and longitudinal movement of joining bar  90  and filler bars  72  relative to one another and relative to bars  28  and  58 . Prior to insertion of joining bars  90 , the diameter of said bars  90  is slightly smaller than the diameter of holes  56  and  88 . After insertion of said joining bars  90 , the portions of joining bars  90  which are disposed within the spaces between adjacent filler bars and between each filler bar and an adjacent deep bar are crimped or otherwise deformed to produce deformed segments  96  ( FIG. 6 ) which in the exemplary embodiment have a vertical dimension which is larger than the diameter of holes  56  and  88  whereby segments  96  serve as spacers which secure filler bars  72  in the desired spaced relationship previously noted. Deformed sections  96  thus define therebetween and alternate with circular segments  98  ( FIG. 9 ) which generally retain their original circular configuration which is slightly smaller than the corresponding holes  56  and  88  in which segments  98  are disposed. The top and bottom of each circular segment  98  thus defines therebetween a diameter or height H 4  which is slightly smaller than the diameter of holes  56  and  88 . Height H 4  is in the exemplary embodiment substantially the same as the outer diameter of the joining bar  90  as noted above. The top and bottom of deformed segments  96  define therebetween a height H 5  which is somewhat larger than height H 4  and the diameter of holes  56  and  88 . Each of height of H 4  and height H 5  is less than that of height H 3  of filler bars  72 . In the exemplary embodiment, height H 4  is about one third that of height H 3 . Joining bars  90  and filler bars  72  are joined directly to one another preferably without any welds therebetween. Joining bars  90  are likewise preferably joined to deep bars  28  without any welds therebetween. 
     The assembly of system  10  is thus complete with the crimping of the tubular joining bars to create the deformed segments although the ends of filler bars  72  may be secured to the corresponding end bars  32  and  34  by optional welds  100  ( FIG. 7 ). If welds  100  are used, they are typically formed between the bottom edge  82  of the respective filler bar  72  and the inner surface of the corresponding end bar  32  or  34 . Thus, while system  10  is typically configured by the use of welds  44 ,  71  and  100 , each of these welds is spaced downwardly from top surface  14  of system  10 , which includes the top edges  46  of deep bars  28  and top edges  80  of filler bars  72 . In the exemplary embodiment, none of the welds in system  10  forms any portion of top surface  14  or communicates therewith. Top surface  14  is primarily formed of top edges  46  and  80  of the parallel deep bars  28  and filler bars  72  although the top edges of end bars  32  and  34  also form a small portion of top edge  14  extending perpendicular to bars  28  and  72  along the outer perimeter of system  10 . As illustrated in the various drawings, each of joining bars  90 , crossbars  58 , holes  56 , holes  88  and slots  54  are in their entirety spaced downwardly from top surface  14 . As illustrated in  FIG. 7 , the height or vertical distance between top edges  64  of crossbars  58  and top surfaces  46  of deep bars  28  is substantially the same as height H 3  so that when system  10  is assembled with filler bars  72  seated atop crossbars  58 , top edges  80  are substantially flush with or at the same height as top edges  46  and the remainder of top surface  14 .  FIG. 7  also illustrates that each joining bar  90  is spaced upwardly a short distance from the top surface  64  of crossbar  58 , while  FIG. 9  shows that each joining bar  90  is parallel to and disposed directly above the corresponding crossbar  58 . As previously noted, the top surface  14  is free of welds in order to provide a clean aesthetic appearance to system  10 . In keeping with this, deep bars  28  and the other bars which form top surface  14  are free of upwardly opening notches communicating with their respective top edges or surfaces wherein such notches are typically used to receive a crossbar or the like so that welding is commonly applied along the top surface within these upwardly opening notches. In addition, the preferred embodiment of system  10  utilizes bars such as deep bars  28 , filler bars  72  and the bars forming outer perimeter  30  which have top edges or surfaces which are horizontally continuous and straight from end to end. While these top edges or surfaces may be smooth, they are often stippled or otherwise roughened to improve traction for vehicular or pedestrian traffic. The top surface  14  of system  10  is thus substantially formed of flat continuous upwardly facing top surfaces of bars which are substantially coplanar and most commonly substantially horizontal. In addition, all of the bars used in system  10  as noted above are either parallel or perpendicular to one another in the exemplary embodiment. Furthermore, none of the components of system  10  are joined to one another by rivets, threaded connection as with bolts and nuts or the like. Although riveted grating systems are very useful in a variety of settings, they are not particularly suited to provide a grating system with spacing between the bars of the top surface which is sufficiently small to prevent the spikes of high heel shoes or lower tips of walking canes from being inserted therein and becoming stuck or causing injury risks. Thus, system  10  in the exemplary embodiment does not utilize rivets or similar fasteners so that the spacing between the filler bars and deep bars as noted above does accommodate pedestrian traffic including spiked heel shoes and walking canes. 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
     Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described.