Abstract:
A variable stackable ramp system for forming ramp assemblies for providing challenging obstacle courses including ones for aerial lift for sport jumping with skateboards, inline skates, bicycles and the like. The ramp system includes ramp modules of at least two different configurations with one being an inclined ramp module having an inclined upper riding or support surface and a straight ramp module having a generally horizontal straight upper riding or support surface. The ramp modules are adapted to be interconnected horizontally and vertically in a variety of orientations to provide ramp assemblies of selectively different overall configurations.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to ramps for providing aerial lift for sport jumping with skateboards, inline skates, bicycles and the like and, more particularly, a system for creating ramp assemblies that can be readily assembled to selectively provide obstacle courses of a variety of configurations with different challenge levels and can be readily disassembled for transport or storage.  
       BACKGROUND OF THE INVENTION  
       [0002]     There are a variety of ramp designs for skateboard, inline skates and bicycle enthusiasts for performing simple aerial jumps or complex aerial acrobatics or other forms of ramp challenges. Such activities are generally performed on straight inclined ramp surfaces or arcuate surfaces some of which may extend as much as a half pipe. In addition there are collapsible and/or modular ramp assemblies some of which are used for the transport of wheeled vehicles such as wheelchairs, carts and the like.  
         [0003]     Even with prior modular or collapsible ramp assemblies such structures provide only limited, selective versatility of the final desired configuration and hence use.  
         [0004]     In the present invention a system for modular ramp assemblies is provided comprising a plurality of similar ramp modules of at least two different structures which can be selectively assembled together vertically and horizontally to define ramp assemblies having a variety of desired overall configurations. Here one of the modules is an inclined ramp module having an inclined upper support, or riding surface and another module a straight module having a straight, flat upper support or riding surface. These surfaces are adapted to be readily operatively joined together to form configurations with desired contours.  
         [0005]     With the versatile system of the present invention the modules can be selectively assembled to provide ramp assemblies of multiple lengths, multiple widths and multiple ramp elevations along with a large variety of overall contours. In addition the modules are provided with unique interfitting structures whereby the modules can be readily manually assembled and disassembled without the need for special tools. In addition each module is of a relatively lightweight structure to facilitate handling.  
       SUMMARY OF THE INVENTION  
       [0006]     In the present invention, a unique modular ramp system is provided to permit the user to selectively vary the overall contour of the ramp assembly as finally assembled.  
         [0007]     Here a plurality of modules of at least two different configurations are used. A first module is provided with an inclined upper support or riding surface with the inclined surface extending substantially over the entire upper surface. A second module is substantially rectangular having a straight, generally horizontal planar upper support or riding surface extending substantially over the entire upper surface.  
         [0008]     In one form the first and second modules are of substantially the same width and length. In addition the upper end of the inclined surface of the inclined ramp module is of substantially the same height as the uniform height of the rectangular module to provide continuity between the support surfaces when operatively connected together in line. This then facilitates assembly of the modules together in a large variety of selected configurations.  
         [0009]     In addition, a simple, unique structure is provided for selectively interconnecting the modules together length wise (end-to-end), width wise (side-by-side), width-to-length (end-to-side) and/or stacked one on top of the other. This simple structure facilitates an ease of assembly and disassembly of the modules into a variety of overall structural ramp assemblies.  
         [0010]     At the same time the capability of providing a selective variety of configurations of ramp assemblies can be done with the use of modules of only two different structures. This then minimizes the overall cost of manufacture for a reasonable cost to the end user.  
         [0011]     Therefore, it is an object of the present invention to provide ramp modules of unique structures for facilitating the formation of ramp assemblies of different overall contours.  
         [0012]     It is another object of the present invention to provide a modular ramp system having a plurality of ramp modules which can be connected together horizontally and vertically in a variety of ways to provide ramp assemblies of numerous, selectively desirable overall contours.  
         [0013]     It is another object of the present invention to provide a modular ramp system including a plurality of ramp modules of different constructions with a structure facilitating relatively easy assembly and disassembly.  
         [0014]     It is another object of the present invention to provide a modular ramp system including a plurality of ramp modules of two different structures to provide ramp assemblies of selectively desirable contours.  
         [0015]     It is also an object of the present invention to provide ramp modules of unique structures for forming unique structural ramp assemblies.  
         [0016]     It is still another object of the present invention to provide a unique modular ramp system.  
         [0017]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0019]      FIG. 1  is a perspective view of one form of a ramp assembly including inclined ramp modules having an inclined, straight upper riding or support surface and straight modules having a straight, planar, generally horizontal upper riding or support or surface;  
         [0020]      FIG. 1   a  is an enlarged fragmentary view of a portion of the ramp assembly taken generally in the Circle  1  a in  FIG. 1 ;  
         [0021]      FIG. 2  is a perspective view similar to  FIG. 1  with a number of inclined ramp modules and straight ramp modules shown in phantom and illustrating different possible horizontal and vertical interconnections between modules for forming a variety of different ramp assemblies;  
         [0022]      FIG. 3  is an upper perspective view of an inclined ramp module with T-shaped connecting protrusions and T-shaped connecting grooves for connection with other ramp modules;  
         [0023]      FIG. 3   a  is a longitudinal sectional view along the length of the inclined ramp module of  FIG. 3  and taken generally along the line and in the direction of the Arrows  3   a - 3   a  in  FIG. 3 ;  
         [0024]      FIG. 4  is a front end elevational view of the inclined ramp module of  FIG. 3  taken in the direction of the Arrows  4 - 4  in  FIG. 3 ;  
         [0025]      FIG. 5  is an enlarged fragmentary view with some parts shown in section of the portion of the inclined ramp module of  FIG. 4  taken generally in the Circle  5  in  FIG. 4 ;  
         [0026]      FIG. 6  is a side elevational view of the inclined ramp module of  FIG. 3  taken in the direction of the Arrows  6 - 6  in  FIG. 3 ;  
         [0027]      FIG. 7  is an upper perspective view of a straight ramp module with T-shaped connecting protrusions and T-shaped connecting grooves for connection with other ramp modules;  
         [0028]      FIG. 7   a  is a longitudinal sectional view along the length of the straight ramp module of  FIG. 7  and taken generally along the line and in the direction of the Arrows  7   a - 7   a  in  FIG. 7 ;  
         [0029]      FIG. 7   b  is a transverse sectional view along the width of the straight ramp module of  FIG. 7  and taken generally along the line and in the direction of the Arrows  7   b - 7   b  in  FIG. 7 ;  
         [0030]      FIG. 7   c  is an enlarged, fragmentary sectional view of a bottom portion of the straight ramp module of  FIG. 7  taken generally in the Circle  7   c  in  FIG. 7   b  depicting the slip resistant foot member as applied to the bottom end of one of the side walls of the straight ramp module;  
         [0031]      FIG. 7   d  is an enlarged end elevational view of the foot member of  FIG. 7   c;    
         [0032]      FIG. 8  is an end elevational view of the straight ramp module of  FIG. 7  taken in the direction of the Arrows  8 - 8  in  FIG. 7 ;  
         [0033]      FIG. 9  is a side elevational view of the straight ramp module of  FIG. 7  taken in the direction of the Arrows  9 - 9  in  FIG. 7 ;  
         [0034]      FIG. 10  is a front, upper perspective view of a connector for securing the ramp modules together when stacked vertically;  
         [0035]      FIG. 11  is a front elevational view of the connector of  FIG. 10 ;  
         [0036]      FIG. 12  is an exploded, fragmentary view showing the layered connection prior to assembly between a straight ramp module on the bottom and an inclined ramp module on top with connectors of  FIGS. 10 and 11  for securing the ramp modules together;  
         [0037]      FIG. 13  is a fragmentary pictorial view to enlarged scale taken generally in the Circle  13  in  FIG. 1  and showing the layered connection of a straight ramp module on the bottom and an inclined ramp module stacked on top of the straight ramp module and secured together with the connector of  FIGS. 10 and 11 ;  
         [0038]      FIG. 14  is a fragmentary sectional view of the layered connection between the straight and inclined ramp modules by the connector of  FIGS. 10 and 11  taken generally along the line and in the direction of the Arrows  14 - 14  in  FIG. 13 ;  
         [0039]      FIG. 15  is a fragmentary vertical sectional view to enlarged scale of the confronting surfaces of the T-shaped protrusion of the lower inclined ramp module and the T-shaped groove of the adjacent lower straight module of  FIG. 2  when connected together and taken generally along the line and in the direction of the Arrows  15 - 15  in  FIG. 2 , with the section line in the direction of Arrows  15 ′- 15 ′ in  FIG. 2  providing a view which would be a mirror image of  FIG. 15  and thus that view has been omitted for purposes of simplicity;  
         [0040]      FIG. 16  is a fragmentary view to enlarged scale of the T-shaped connecting protrusion of the straight ramp module of  FIG. 8  taken generally in the Circle  16  in  FIG. 8 ;  
         [0041]      FIG. 17  is a fragmentary view to enlarged scale of the T-shaped connecting groove of the straight ramp module of  FIG. 8  taken generally in the Circle  17  in  FIG. 8 ;  
         [0042]      FIG. 18  is a fragmentary view to enlarged scale taken generally vertically downwardly in the direction of the Arrows  18 - 18  in  FIG. 2  depicting the upper end of the connection between a T-shaped connecting protrusion on the straight ramp module and a T-shaped connecting groove on the inclined ramp module; and  
         [0043]      FIG. 19  is a fragmentary view depicting the T-shaped protrusion and T-shaped groove of  FIG. 18  separated prior to assembly. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0044]     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0045]     Looking now to  FIG. 1 , a modular ramp assembly  10 , of one form, is shown and is made up of a plurality of inclined ramp modules  12  of one uniform structure and straight ramp modules  14  of a second uniform structure. The inclined ramp modules  12  are generally of a right triangular, wedge shape while the straight ramp modules  14  are generally of a rectangular box shape. Both the inclined ramp modules  12  and straight ramp modules  14  are of a generally lightweight, hollow construction to be described.  
         [0046]      FIGS. 3, 4  and  6  show the inclined ramp module  12 , to have an inclined, straight, planar rectangular upper support or riding surface  16  supported on opposite sides by generally triangularly shaped side walls  18 a and  18 b and at the upper end by a generally rectangularly shaped end wall  20 . The side wall  18   a  has a plurality of longitudinally spaced T-shaped connecting protrusions  22   a  and  24   a  and a plurality of longitudinally spaced T-shaped connecting channel grooves  26   a  and  28   a . As can be seen the connecting protrusions  22   a  and  24   a  are alternately spaced relative to the connecting channel grooves  26   a  and  28   a . The opposite side wall  18   b  has T-shaped connecting protrusions  22   b  and  24   b  which are longitudinally offset from the opposite sided connecting protrusions  22   a  and  24   a  and are substantially in transverse alignment with the T-shaped channel grooves  26   a  and  28   a , respectively. Likewise, the side wall  18   b  has T-shaped channel grooves  26   b  and  28   b  which are substantially in transverse alignment with the T-shaped protrusions  22   a  and  24   a , respectively. Such alignment serves a connecting purpose to be described. The end wall  20  has a T-shaped connecting protrusion  30  and a T-shaped connecting channel groove  32 .  FIG. 5  is a fragmentary partially sectioned view depicting the upper end of the T-shaped protrusion  24   a.    
         [0047]      FIGS. 7, 8  and  9  show the straight ramp module  14 .  
         [0048]     As will be seen the T-shaped protrusions and T-shaped grooves provide a unique and simple way of slidably connecting the ramp modules to form assemblies of a variety of horizontal and vertical configurations.  
         [0049]     The straight ramp module  14  has a generally horizontal rectangular, straight or planar upper riding or support surface  34  which is supported on opposite sides by generally rectangularly shaped side walls  36   a  and  36   b  and at opposite ends by generally rectangularly shaped front and rear end walls  38   a  and  38   b , respectively. The side wall  36   a  has a pair of longitudinally spaced T-shaped connecting protrusions  40   a  and  42   a  and a plurality of longitudinally spaced T-shaped connecting channel grooves  44   a  and  46   a . Again, the connecting protrusions  40   a  and  42   a  are alternately spaced relative to the connecting channel grooves  44   a  and  46   a . The opposite side wall  36   b  has T-shaped connecting protrusions  40   b  and  42   b  which are longitudinally offset from the opposite side protrusions  40   a  and  42   a  and are substantially in transverse alignment with the T-shaped channel grooves  44   a  and  46   a . Likewise the side wall  36   b  has T-shaped connecting channel grooves  44   b  and  46   b  which are longitudinally offset from the opposite side channel grooves  44   a  and  46   a  and are substantially in transverse alignment with the T-shaped protrusions  40   a  and  42   a , respectively.  
         [0050]     The front end wall  38   a  has a T-shaped connecting protrusion  48   a  and a transversely spaced T-shaped connecting channel groove  50   a . The rear end wall  38   b  has a T-shaped connecting protrusion  48   b  in longitudinal alignment with the T-shaped channel groove  50   a  and a transversely spaced T-shaped connecting channel groove  50   b  in longitudinal alignment with the T-shaped protrusion  48   a.    
         [0051]     In all of the above, the T-shaped protrusions and T-shaped grooves on the inclined ramp modules  12  and on the straight ramp modules  14  are of similar constructions and equally spaced with the T-shaped protrusions adapted to slidingly fit within the T-shaped channel grooves to connect an inclined module  12  and straight ramp module  14  together end-to-end. In this regard the shortened T-shaped protrusions  22   a, b  and  24   a, b  and shortened T shaped channel grooves  26   a, b  and  28   a, b  of the inclined ramp modules  12  are of substantially the same contour as the full length T-shaped protrusion  30  and channel groove  32  at their same lower sections.  
         [0052]     At the same time, the transverse spacing between the protrusion  30  and channel groove  32  in the end wall  20  of inclined ramp modules  12  and between the end protrusions  48   a  and  48   b  and end channel grooves  50   a  and  50   b  in end walls  38   a  and  38   b  of the straight ramp modules  14  is inversely the same to provide interfitting end-to-end connection. Also the longitudinal spacing between the side protrusions  22   a ,  24   a  and side channel grooves  26   b ,  28   b  and side protrusions  22   b ,  24   b  and side channel grooves  26   a ,  28   a  in side walls  18   a ,  18   b  of the inclined ramp modules  12  is inversely the same to provide interfitting side-by-side connection between two inclined ramp modules.  
         [0053]     Along the same line, the protrusion  48   a  and channel groove  50   a  in the end wall  38   a  of the straight ramp modules  14  are longitudinally in line with the channel groove  50   b  and protrusion  48   b , respectively, in the opposite end wall  38   b  to provide end-to-end connection. Also the longitudinal spacing between the channel grooves  44   a ,  46   a  on side wall  36   a  and protrusions  40   b ,  42   b  on side wall  36   b  is the same placing them in transverse alignment and the spacing between protrusions  40   a ,  42   a  on side wall  36   a  and channel grooves  44   b ,  46   b  is the same also placing these in transverse alignment to provide interfitting side-by-side connection between two straight ramp modules  14 .  
         [0054]     In this regard, it can be seen from  FIG. 2  that the inversely uniform spacing of T-shaped connecting grooves and T-shaped connecting projections on the end and side surfaces of the inclined ramp modules  12  and straight ramp modules  14  are uniform whereby the end wall  20  of the inclined ramp module  12  can also be connected to either of the side walls  36   a ,  36   b  of the straight ramp modules  14  and likewise either end wall  38   a ,  38   b  of a straight ramp module  14  can be connected to either of the side walls  36   a ,  36   b  of another straight ramp module  14 . Thus the inclined ramp modules  12  and straight ramp modules  14  can be connected together in a substantial variety of vertical and horizontal combinations. Examples of such variations in assembly are shown in  FIG. 2  with some members shown in phantom. In this regard, it can be seen in  FIG. 2  that ramp assemblies can be selectively erected with inclined ramps  12  at the beginning and end such that there may be little or no aerial left. This clearly shows that ramp assemblies can be assembled to provide obstacle courses of a selected variety of challenge levels. It can also be seen then that the orientation of the T-shaped projections and T-shaped grooves of the inclined ramp modules  12  and straight ramp modules  14  facilitates the ease of assembly since no particular orientation is required for end-to-end or side-to-side connection.  
         [0055]     As can be seen from  FIG. 1 , the width and height of the end wall  20  of the inclined ramp modules  12  and of the end walls  38   a  and  38   b  of the straight ramp modules  14  are the same such that an inclined ramp module  12  and straight ramp module  14  are in an in-line alignment when assembled end-to-end. In addition the lengths of the inclined ramp modules  12  and the straight ramp modules  14  are the same to provide alignment for vertical stacking when an inclined ramp module  12  is stacked on top of a straight ramp module  14 .  
         [0056]     In order to secure the different ramp modules together for vertical stacking a separate connecting member is provided. Looking now to  FIGS. 10 and 11  a connector  52  is shown and is of a generally open structure having an inner substantially enclosed portion  54  having an opening  56  at its lower end and a closed cap portion  58  at its upper end. A generally U-shaped, open flanged, channel  60  extends outwardly from the forward side. The connector  52  has an upper section  62  and a lower section  64 . The lower section  64  is somewhat larger transversely than the upper section  62  to define an outer alignment and stop ridge  66  which serves a purpose to be described.  
         [0057]     The T-shaped connecting protrusions, such as  22   a ,  24   a , and T-shaped channel grooves, such as  26   a ,  28   a , are uniquely constructed for connecting the inclined ramp modules  12  and straight ramp modules  14  together, side-by-side or end-to-end. At the same time the connectors  52 , T-shaped protrusions and T-shaped channel grooves are uniquely constructed for providing connections between the inclined ramp modules  12  and straight ramp modules  14  for vertical stacking.  
         [0058]     All of the T-shaped projections and T-shaped channel grooves are of an identical configuration and construction except for the shortened T-shaped protrusions  22   a, b  and  24   a, b  and shortened T-shaped channel grooves  26   a, b  and  28   a, b  on the side walls  18   a ,  18   b  of the inclined ramp modules  12 . However, the configuration of the shortened T-shaped projections and T-shaped grooves are the same as the corresponding lower portions of the full length T-shaped projections and T-shaped grooves.  
         [0059]     A representative example of the structure of the full length T-shaped protrusions and T-shaped channel grooves can be seen in  FIG. 16  which is of the T-shaped protrusion  48   a  and  FIG. 17  which is of the T-shaped channel groove  50   a . These views are taken from  FIG. 8  which, as can be seen, is at the front end wall  38   a  of the straight ramp module  14 . Other features of the T-shaped protrusions  48   a  and of the T-shaped channel groove  50   a  can be seen in  FIGS. 12, 15 ,  18  and  19 .  
         [0060]     Looking now to  FIGS. 16, 18  and  19  the T-shaped protrusion  48   a is of a tapered construction with a narrower upper end  68  tapering to a wider lower end  70 . The protrusion  48   a  has an outer rectangular section  72  connected to the end wall  38   a  by a narrower neck section  74 . The rectangular section  72  and neck section  74  are similarly tapered and in one form of the invention the taper angle A was selected to be around 1.5°. As can be seen in  FIG. 12 , the protrusion  48   a  is of a hollow construction with the neck section  74  opening into the generally hollow interior of the straight ramp module  14 . The T-shaped protrusion  48   a  is closed at the upper end  68  and open at the lower end  70 . In this regard, the shorter T-shaped protrusions on the side walls  18   a  and  18   b  of the inclined ramp module  12  are also hollow and closed at their upper ends as can be seen with the T-shaped protrusion  24  in  FIG. 5 .  
         [0061]     Looking now to  FIGS. 17, 18  and  19 , the T-shaped channel groove  50   a  is also of a tapered construction but which is of a reverse taper relative to that of the T-shaped protrusion  48   a . Thus the channel groove  50   a  tapers from a wider upper end  76  to a narrower lower end  78 . The T-shaped channel groove  50   a  has an outer, slotted narrow neck section  80  connected to a wider inner rectangular groove section  82 . The rectangular groove section  82  is closed at its inner surface  84  whereby the channel groove  50   a  is not open to the hollow interior of the straight ramp module  14 . As can be seen in  FIG. 17 , the neck section  80  and rectangular groove section  82  are similarly tapered at an angle AA of around 1.5° which is thus substantially the same as the reverse taper angle A of the T-shaped protrusion  48   a.    
         [0062]     Looking now to  FIGS. 18 and 19 , the size of the T-shaped protrusion  48   a  at its wider lower end  70  is substantially the same as the size of the T-shaped channel groove  50   a  at its narrower lower end  78  to provide mating engagement at the location. However, the size of the narrower upper end  68  of the T-shaped protrusion  48   a  is less than the size of the wider upper end  76  of the T-shaped channel groove  50   a  to provide a preselected clearance for a purpose to be seen.  
         [0063]      FIG. 15  shows the vertical relationship of the T-shaped protrusion  48   a  when interconnected into the T-shaped channel groove  50   b . Here it can be seen that the outer rectangular section  72  is angled inwardly lengthwise from the lower end  70  to the upper end  68  at an angle B. The inner surface  84  of the rectangular groove section  82  of the T-shaped groove  50   a  is also angled inwardly lengthwise from the lower end  78  to the upper end  76  at angle BB. Here in one form of the invention the angle B was set at around 0.75° while the angle BB was also set at around 0.75°. This provides a preselected clearance at the upper ends  68 ,  76  while the lower ends  70 ,  78  are in mating engagement.  
         [0064]     The noted clearances facilitate assembly of the ramp modules together for horizontal in-line connection, i.e. end-to-end, side-to-side or end-to-side. The clearance also facilitates assembly of the ramp modules in a variety of vertically stacked relationships. In addition while the tapers and inclinations of the T-shaped protrusions  48   a  and T-shaped channel grooves  50   a  facilitate assembly they also facilitate manufacture by assisting in ejection of the modules from the molds in the molding process.  
         [0065]     As noted in order to securely stack one ramp module upon another, the connectors  52  are used. This can be seen in  FIGS. 12-14  where an inclined ramp module  12  is being stacked upon a straight ramp module  14 . First each of the connectors  52  is located over the upper end  68  of the T-shaped protrusions such as protrusions  42   a  and  48   a . Here the lower section  64  of the connector  52  will fit snugly on the upper end  68 . With the connectors  52  in place next the inclined ramp module  12  is placed on top of the straight ramp module  14  with the T-shaped protrusion  24   a  on the side wall  18   a  and protrusion  30  on the end wall  20  in line with the T-shaped protrusion  42   a  on the side wall  36   a  and the T-shaped protrusion  48   a  on the front end wall  38   a . The opening at the lower end  70  of the T-shaped protrusion  48   a  is of a contour to move over the upper section  62  of the connector  52  with the bottom side of the lower end  70  of the T-shaped protrusion  48   a  engaging the outer stop ridge  66 . The inclined ramp module  12  is pressed downwardly until the bottom of the inclined ramp module  12  engages the straight, planar upper riding or support surface  34  of the straight ramp module  14 .  
         [0066]     Where the vertical stacking is an inclined ramp module  12  on a straight ramp module  14 , connectors  52  will be applied to the T-shaped protrusions on both side walls  36   a ,  36   b  and the front end wall  38   a . Where a straight ramp module  14  is stacked on top of another straight ramp module  14 , then connectors  52  will be applied to each of the T-shaped protrusions on both side walls  36   a ,  36   b  and both end walls  38   a ,  38   b.    
         [0067]     In the event, it is desired to double the width of the ramp assembly  10 , a second straight ramp module  14  will first be secured side-by-side to the first straight ramp module  14  with the opposite side wall  36   b  located next to the side wall  36   a . Here the T-shaped protrusions  40   a ,  42   a  will be connected with the T-shaped grooves  44   b ,  46   b  and the T-shaped grooves  44   a  and  46   a  will be connected with the T-shaped protrusions  40   b ,  42   b . Now the connectors  52  will be located over the T-shaped protrusions  40   a ,  42   a  and in a generally clearance fit in the related T-shaped grooves  44   b ,  46   b . The clearance between the upper end of a T-shaped protrusion  48   b  and the upper end of a T-shaped groove  32  can be readily seen in  FIGS. 18 and 19 . Now the inclined ramp module  12  will be assembled onto the first straight ramp module  14 , as noted. Next a second inclined ramp module  12  will be placed on top of the second straight ramp module  14  with the T-shaped protrusions  22   b ,  24   b  on side wall  18   b  located in the T-shaped grooves  26   a ,  28   a  on side wall  18   a  and also with the T-shaped protrusions  22   a ,  24   a  on the side wall  18   a  located in the T-shaped grooves  26   b ,  28   b  on the side wall  18   b . In addition further stacked connection could be provided between the side-to-side surfaces utilizing connectors  52  between the T-shaped protrusion  40   b  and  42   b  on the straight ramp module  14  and the T-shaped protrusions  22   b  and  24   b  on the inclined ramp module  12 . It can be seen, however, that the straight ramp module  14  can be connected side-by-side with two side walls  36   a  or two side walls  36   b  connected together by simply rotating the second ramp module  14  by 180°. This will bring the T-shaped protrusions  22   a ,  24   a  and the T-shaped grooves  26   a ,  26   b  on the second side wall  18   a  in alignment with the T-shaped grooves  26   a ,  26   b  and T-shaped protrusions  22   a ,  24   a  on the first side wall  18   a . The same versatility is true in connecting one end wall  38   a  to another end wall  38   a  or  38   b  to  38   b  for end-to-end connection.  
         [0068]     As can be seen from  FIGS. 1 and 2 , the ramp system of the present invention permits the user to create ramp assemblies of varying configurations. An example of one such ramp assembly  10  is shown in  FIG. 1 . Here a first inclined ramp module  12  is connected end-to-end with a first straight ramp module  14  at ground level. This is done simply by slidably moving the T-shaped protrusion  48   b  on the end wall  38   b  into the T-shaped channel groove  32  on the end wall  20  and at the same time moving the T-shaped channel groove  50   b  on the end wall  38   b  over the T-shaped protrusion  30  on the end wall  20 . In this regard a similar connection could be made with the end wall  38   a . Next the overall length can be extended by connecting a second straight ramp module  14  end-to-end with the first straight ramp module  14  at ground level. This is done similarly to the above by placing the T-shaped protrusion  48   b  on the rear end wall  38   b  into the T-shaped channel groove  50   a  on the front end wall  38   a  and slidably moving the T-shaped channel groove  50   b  on the rear end wall  38   b  over the T-shaped protrusion  48   a  on the front end wall  38   a.    
         [0069]     Now a second inclined ramp module  12  is placed on the upper riding or support surface  34  on the first straight ramp module  14 . These stacked ramp modules  12  and  14  are then connected together by use of the connectors  52 . Looking now to  FIGS. 10-12 , connectors  52  are located over the upper ends of the T-shaped protrusions  40   a, b  and  42   a, b  on the side wall  36   a  of straight ramp module  14  and on the T-shaped protrusion  48   a  on the front end wall  38   a.    
         [0070]     Now to extend the height of the ramp assembly  10  as shown a third straight ramp module  14  is located on the planar upper support surface  34  of the second straight ramp module  14 . As this is done the T-shaped channel groove  50   b  and T-shaped protrusion  48   b  on the rear end wall  38   b  of the second straight module  14  are interconnected with the T-shaped protrusion  30  and T-shaped channel groove  32  on the front end wall  20  of the second inclined module  12 . At the same time connectors  52  have already been located on the upper ends of the T-shaped protrusions  40   a, b  and  42   a, b  of the second straight module  14  and are moved into the lower ends of the aligned T-shaped protrusions  40   a, b  and  42   a, b  on the third straight module  14 . This is done by moving the lower or bottom end of the T-shaped protrusions  40   a, b  and  42   a, b  over the upper section  62  of the connectors  52  against the outer stop ridge  66 .  
         [0071]     Now the assembly  10  is completed by locating a third inclined ramp module  12  on the planar upper support surface  34  of the third straight ramp module  14 . Again the connectors  52  are first located over the upper ends of the T-shaped protrusions  40   a, b  and  42   a, b  and the T-shaped protrusions  22   a , b and  24   a, b  are located over the upper section  62  of the connectors  52  to secure the modules together.  
         [0072]     The outer edge of the riding or support surface  16  at the end wall  20  of the inclined ramp modules  12  and the outer edges of the riding or support surface  34  at the end walls  38   a, b  of the straight ramp modules  14  are arcuately formed to avoid stress. Such arcuate outer edges  86  and  88  are shown in  FIG. 1   a . In order to cover the slight gap between the adjacent edges  86  and  88  at the juncture of the end walls  20  and  38   b , the inclined riding or support surface  16  of the inclined module  12  is provided with a somewhat flexible, generally tapered lip  90  at its lower, front end. This provides for a relatively smooth transition between the two adjacent inclined support surfaces  16  on the lower and upper inclined ramp modules  12  so as to render the gap between the adjacent edges  86  and  88  substantially imperceptible to the user.  
         [0073]      FIG. 2  shows examples of the variety of horizontal and vertical interconnections between the inclined ramp modules  12  and straight ramp modules  14  to provide a selective variety of modular ramp assemblies generally indicated by the numeral 10′. As noted a number of the inclined ramp modules  12  and straight modules  14 , are shown in phantom to indicate the variety of interconnections for different ramp assemblies. Thus the same end user can have the versatility of setting up ramp assemblies of different configurations for different objectives and even different uses, i.e. inline skates, skateboards, etc. This then allows the user to set up ramp assembly obstacle courses with different degrees of challenge.  
         [0074]     Both the inclined upper riding or support surface  16  on the inclined ramp module  12  and the straight planar upper riding or support surface  34  on the straight ramp module  14  can be roughened to enhance gripping of the engaging rolling member such as bike tires, skate rollers, etc. and to assist in traction and to inhibit slippage especially if wet. In one form, the roughened surfaces were formed in molding. However, it should be understood that such roughened surfaces could be created after molding. In this regard, it can be seen in  FIG. 7  that in some forms of a ramp assembly the planar upper support surface  34  of at least one straight ramp module  14  will be exposed for engagement by the rolling member. For purposes of simplicity of the drawings only the inclined ramp module  12  in  FIGS. 3 and 4  and straight ramp module  14  in  FIG. 7  are shown with roughened surfaces.  
         [0075]     As noted, both the inclined ramp modules  12  and straight ramp modules  14  are of a hollow construction and as such are designed to be molded from a plastic material. In one form of the invention the plastic material was a high density polyethylene (HDPE). In this regard, the connectors  52  can be molded from the same material.  
         [0076]     In order to facilitate molding of the inclined ramp modules  12  and straight ramp modules  14  and to provide modules that are relatively light weight, a hollow structure is provided with numerous internal ribs.  
         [0077]     Such a structure for the inclined ramp module  12  can be seen in the longitudinal section of  FIG. 3   a . There, a plurality of longitudinally extending main ribs  92  connect the inclined riding or support surface  16  with the end wall  20 . Only one rib  92  is shown for purposes of simplicity. At the same time a plurality of transverse main ribs  94  are connected between the inclined support surface  16 , the side walls  18   a ,  18   b , and the longitudinal ribs  92 . The center portions of the ribs  92  and  94  are of a reduced vertical length while the sides extend to the bottom.  
         [0078]     The internal structure for the straight ramp module  14  can be seen in  FIGS. 7   a  and  7   b .  FIG. 7   a  shows a plurality of longitudinally extending main ribs  96  which connect the riding or support surface  34  with end walls  38   a, b .  FIG. 7   b  shows a plurality of transversely extending main ribs  98  which connect the support surface  34  with the side walls  36   a, b  and are interconnected with the longitudinal ribs  96 . Again the center portions of the ribs  96  and  98  are of a reduced vertical length while the sides extend to the bottom. These structures facilitate the molding process and the production of the inclined modules  12  and straight module  14  of a lightweight structure.  
         [0079]     In one form of the invention the inclined module  12  and straight module  14 , generally of the construction noted, each has five generally equally spaced longitudinal main ribs  92  and  96 , respectively, and five generally equally spaced transverse main ribs  94 ,  98 , respectively. As noted the longitudinal main ribs  92  and  96  extend for substantially the full length of the ramp modules  12  and  14  while the transverse main ribs  94  and  98  extend for substantially the full width of the ramp modules  12  and  14 . In addition, the Inclined module  12  has four longitudinal rib segments  93  in between the five longitudinal main ribs  92  and four transverse rib segments  95  in between the five transverse main ribs  94 . The rib segments  93  and  95  are also connected to the support surface  16  but do not extend for the full length or full width of the inclined ramp module  12 . Similarly, each of the straight ramp modules  14  has four longitudinal rib segments  97  In between the five longitudinal main ribs  96  and four transverse rib segments  99  in between the five transverse main ribs  98 . The rib segments  97  and  99  are also connected to the planar support surface  34  but which do not extend for the full length or full width of the straight ramp module  14 .  
         [0080]     As can be seen the overall strength and rigidity of the riding or support surfaces  16  and  34  are thereby substantially enhanced. Also it can be seen that the outer lower ends of the main ribs  92  and  94  of the inclined ramp module  12  and the main ribs  96  and  98  of the straight ramp module  14  extend to the bottom of the respective ramp modules  12  and  14 . These then provide a distributed support surface against the ground or when engaged with the riding or support surfaces  34  when in a stacked condition.  
         [0081]     In this regard, in one form of the invention the inclined modules  12  and straight modules  14  where made with side walls  18   a, b  and  36   a, b  of the same longitudinal length (Li, Ls), and end walls  20  and  38   a, b  of the same transverse width (Wi, Ws), and of the same vertical height (Hi, Hs). As such in one form, the longitudinal length (Li, Ls), was around  36  inches, the transverse width (WI, Ws) was around 25.5 inches and the vertical height (Hi, Hs) was around    12   inches. In this regard, the tapered lip  90  extends longitudinally slightly past the length Li of side walls  18   a, b  at the lower end to provide the desired coverage of the gap between the confronting edges  86  and  88  of the adjacent end walls  20  and  38   b . Also in this form the angle of inclination AI of the riding or support surface  16  of the inclined module  12  was selected to be around 19°. With such a structure the support surfaces  16  and  34  and main ribs  92 ,  94 ,  96  and  98  could be made of a relatively small gauge or thickness. As such the support surfaces  16  and  34  could be made around 0.140 inches thick; the side walls  18   a, b  and  36   a, b  and end walls  20  and  38   a, b  could be made around 0.100 inches thick; and the main ribs  92 ,  94 ,  96  and  98  could be made around 0.060 inches thick. The rib segments  93 ,  95 , 97  and  99  could be of the same thickness as the main ribs  92 ,  94 ,  96  and  98 . Some of the above structures would be somewhat slightly tapered to facilitate molding. Such hollow, relatively thin wall constructions can produce generally lightweight ramp modules, i.e. around 17 pounds for the straight module  14  and around 11 pounds for the inclined module  12 . Yet it is believed that the constructions as noted can safely handle loads at least up to 300 pounds.  
         [0082]     In order to provide resistance to slippage on the ground level a foot member can be provided to be selectively placed on portions of the bottom ends of the side walls  18   a, b  and  36   a, b  and the end walls  20  and  38   a, b . Such a foot member  100  can be seen in  FIG. 7   c  as applied to side wall  36   a  and in  FIG. 7   d  prior to application to a side wall  36   a . Here the foot member  100  is provided of a generally U-shaped cross-section having an open channel  102  which is of a size to be snugly located on the bottom end of the outer side walls and outer end walls of the inclined ramp modules  12  and straight ramp modules  14  of a ramp assembly.  
         [0083]     Looking now to  FIG. 7   d  the U-shaped foot member  100  has a substantially wider bottom engagement segment  104  to provide a desired amount of surface contact with the surface on which the ramp assembly  10  is located to inhibit slippage. The foot member  100  has a lower section  106  which is of a generally uniform wall thickness and is connected to an upper tapered section  108  of varying reduced wall thickness. At the same time an upper open end  110  of the foot member  100  is partially closed while the lower end  112  is of a width substantially the same as the wall thickness of the outer side walls  18   a, b  and  36   a, b  and outer end walls  36   a, b . Thus the foot member  100  can be resiliently moved through the open end  110  onto the outer side walls  18   a, b  and  36   a, b  and end walls  38   a, b  with the upper section  108  closing to grip the side walls and end walls to assist in retaining the foot member  100  in place. In addition the foot member  100  can also be applied to the outer lower ends of the main ribs  92 ,  94 ,  96  and  98 . In this regard, the main ribs  92 ,  94 ,  96  and  98  are of a lesser thickness than that of the side walls  18   a, b  and  36   a, b  and end walls  20  and  38   a, b . This will provide a clearance with the lower end  112  of the channel  102 . However, the open end  110  of the foot member  100  will still be moved apart resiliently upon application over the main ribs  92 ,  94 ,  96  and  98  and will be closed to grip the main ribs  92 ,  94 ,  96  and  98  to retain the foot member  100  in place. The foot member  100  is also made of a generally resilient, elastic material such as an EPDM rubber of around 75 to around 80 durometer whereby discontinuities in the ground supporting surface can also be substantially accommodated. The foot member  100  can be simply made of strips which can be cut to preselected limited lengths to fit the accessible portions at the bottom ends of the outer side walls  18   a, b  and  36   a, b  and outer end walls  38   a, b . It could also be applied to the end wall  20  only where a single inclined ramp module  12  is used alone. In one form, the engagement segment  104  was made around 0.30 inches wide. For purposes of simplicity the foot member  100  is shown only applied to the straight ramp module  14  in  FIGS. 7   a  and  7   b . It should be understood that the foot member  100  may not need to be applied to each of the multiple locations as shown. It should be noted that even where the foot member  100  is not applied to the main ribs  92 ,  94 ,  96  and  98 , there could still be ground contact by the lower ends of the main ribs when riding load is being applied as the foot member  100  elastically deforms.  
         [0084]     Thus it can be seen that the ramp assemblies of various configurations can be readily assembled and disassembled by vertical sliding movement to engage or disengage the T-shaped protrusions from the T-shaped channel grooves and a simple type of action for stacking or unstacking the ramp modules.  
         [0085]     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.