Patent Publication Number: US-7914012-B2

Title: Independent suspension system for in-line skates

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a DIVISIONAL application claiming the benefit of priority of the co-pending U.S. Utility Non-Provisional patent application Ser. No. 11/985,473, with a filing date of 15 Nov. 2007, which claims the benefit of priority of U.S. Utility Provisional Patent Application No. 60/859,563, filed 16 Nov. 2006, the entire disclosures of all Applications are expressly incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates to in-line skates and, more particularly, to an independent suspension system thereof that uses an elastomer in the form of a synthetic resin spring, a non-limiting example of which is a polyurethane spring. 
     (2) Description of Related Art 
     In-line skates are well known, and have essentially replaced regular roller-skates, and are used by speed skaters and ice-hockey players for dry-land activities. In general, in-line skates are used outside on sidewalks and other road surfaces that may be uneven, which can cause stress on the wheels, boots, and other structural elements of the skate as well as discomfort for the skater. 
     In the past, systems and mechanisms have been developed to improve the suspension system of the in-line skate so that the skate will absorb the shocks caused on the skate by uneven riding surfaces. Reference is made to the following few exemplary U.S. Patent Publications, including U.S. Pat. Nos. 7,048,281; 6,644,673; and 6,454,280, all to Longino, the entire disclosures of all of which patents is expressly incorporated by reference in their entirety herein. 
     As illustrated in  FIG. 1A , prior art conventional suspension systems use a polyurethane spring  100  that has a smooth and even outer surface, and that is captured within a smooth and even cavity  106  of rocker arms  102  and  104 , which are compressed into the polyurethane spring  100 . As best illustrated in  FIGS. 1B to 1G , the prior art polyurethane spring  100  generally includes a through-hole  108 , which provides a more flexible spring compared with solid polyurethane springs that are more rigid. As seen in  FIGS. 1B to 1D , the through-hole  108  can be of any general shape wherein each shape provides for different degrees of variability for the spring  100 . In addition to the regular elasticity of the polyurethane, the through-hole  108  provides space into which polyurethane material can additionally move. The size and dimension of the through-hole  108  can effect the rigidity of the spring  100 , and as can be appreciated, the larger the surface area of the through-hole  108 , the more variability that is provided by the spring  100 . 
     In prior art springs  100 , in order to further adjust their strength or resistance, an adjustment post  110  ( FIG. 1E ) is placed into the through-hole  108 . The post  110  placed within the through-hole  108  reduces the size (volume) of the void space of the through-hole, and hence, reducing the space into which polyurethane material can additionally move and thereby, increasing spring  100  resistance. The size of the adjustment post  110  from the furthest edges formed by the wave-like shape is proximate the size of the through-hole  108  so that the post  110  fits easily into the through-hole  108  while engaging the spring  100  at the sides of the through-hole  108 . The adjustment rod  110  is made of a suitably rigid material so that it can contribute to the variability of the spring  100 . The adjustment rod  110  must also be flexible so that when the spring  100  flexes within the confines of the hole  108  the integrity of the rod is maintained and that it will return to its original shape when the force is removed from the spring.  FIGS. 1F and 1G  illustrate the spring  100  with the adjustment post  110  in two different positions thereby changing and varying the rigidity of the spring  100 . In  FIG. 1F , the post  110  is in the vertical position whereby the spring material is given the greatest area to flex within the hole  108  (least resistance); in  FIG. 1G , the post  110  is in the horizontal position whereby the spring material does not have the same ability to deform, or flex within the hole and provides a more rigid spring than that compared to  FIG. 1F . In addition, the adjustment rod  110  itself contributes to the rigidity of the spring  100 . The adjustment post  110  can be rotated between the vertexes of the hole  108  to vary the strength or resistance of the spring. As the post  110  rotates from a vertical orientation to a horizontal orientation, the strength of the spring is enhanced. As the post is moved to the horizontal, the resistance within the space is increased against the pressing of the rocker arms, thereby making a more rigid spring. 
     As described above, regrettably, the prior art suspension systems are complicated, and require user meddling with the suspension system for adjustment of the spring resistance for specific users. Further, having the holes within springs also means that the springs would not function properly with heavier weight individuals, and hence, the need for the post. Therefore, the prior art suspension systems must be particularized and specifically made and adjusted for different individuals, which makes the use and manufacturing of the entire in-line skates too complicated and costly, with variations in the quality of the end product. 
     In addition, the prior art suspension systems have a limited range of resistance for different user weights, and have an undesired responsiveness in terms of their rate of resistance in relation to shifting of user weight during the ride of the in-line skates (for example, during quick, sharp turns when large amounts of force are applied to the spring). Further, the prior art suspension systems that use the adjustment rod are prone to breakage. In particular, when the adjustment rod is turned horizontally, it can only contact two of the vertexes of the holes while the rest of the vertices remain free. This creates uneven resistances within the spring hole, which can easily cause cracking and breakage of the spring due to fatigue under very large forces on only two vertexes. 
     Accordingly, in light of the current state of the art and the drawbacks to current polyurethane springs mentioned above, a need exists for a spring apparatus that would provide a wide range of resistance to accommodate a smooth ride against the application of different forces and, more particularly, that would provide a rate of resistance that would commensurately vary and be correspondingly responsive in relation to shifting of user weights during the ride of the in-line skates, without requiring any adjustments. In addition, a need exists for such an apparatus that would be simple and not require user meddling with the suspension system for adjustment of resistance and rate of resistance of the spring. 
     BRIEF SUMMARY OF THE INVENTION 
     One aspect of the present invention provides a polyurethane biasing mechanism (e.g., a polyurethane spring), comprising:
         a first surface contact area with a first mass having a durometer that provides a first resistance and a first rate of resistance responsive to application of forces;   a second surface contact area with a second mass having the same durometer that provides a second resistance and a second rate of resistance responsive to the forces;   with the first resistance and the first rate of resistance different from the second resistance and second rate of resistance, a combination of which provides a rate of resistance that commensurately varies and is correspondingly responsive in relation to varying forces.       

     Another aspect of the present invention provides a method for varying a resistive response and resistive rate of response of a polyurethane biasing mechanism, comprising:
         increasing a contact surface area and lowering a mass of the polyurethane spring by providing:   two mass regions and two surface contact areas, including:   a first surface contact area with a first mass having a durometer that provides a first resistance and a first rate of resistance responsive to application of forces;   a second surface contact area with a second mass having the same durometer that provides a second resistance and a second rate of resistance responsive to the forces;   with the first resistance and the first rate of resistance different from the second resistance and second rate of resistance, a combination of which provides a rate of resistance that commensurately varies and is correspondingly responsive in relation to varying forces.       

     Yet another aspect of the present invention provides a spring, comprising:
         a polyurethane material having an axial length L, a width W, and a thickness T;   a top surface that includes a slightly concaved section that is extended longitudinally, along the axial length L of the spring;   the slightly concaved section includes lateral edge depressions extending longitudinally, along the axial length L of the spring;   two lateral side surfaces, and extending longitudinally along the axial length L of the spring;   the lateral side surfaces includes a plurality of notches that are formed into the lateral side surfaces of the spring;   the notches are aligned laterally along the axial length L of the spring, forming an alternating notch and protuberance;   each notch of the plurality of notches is comprised of a substantially flat base, with the curved protuberances forming two side walls of each notch;   a bottom surface.       

     A further aspect of the present invention provides a set of rocker arms, comprising:
         a first rocker arm having a first axial length L, a first axial width W, and a first height H;   a second rocker arm having a second axial length L, a second axial width W, and a second height H;   the first rocker arm having a first skate wheel connection;   the second rocker arm a second skate wheel connection;   a pivoting axle connection, the pivoting axle connection pivotally coupling the first rocker arm and the second rocker arm;   a spring housing:   the pivoting axle connection forming a bottom of the spring housing;   the spring housing further including two lateral side walls that are longitudinally extended along the axial width W of the set of rocker arms, with each lateral side wall, comprising:   a plurality of flanges, the flanges are aligned laterally along the axial width W of the forming an alternating protuberance and depression; and   a top.       

     Still a further optional aspect of the present invention provides a set of rocker arms, wherein:
         the first axial length L, the first axial width W, and the first height H are equal to the second axial length L, the second axial width W, and the second height H.       

     Another aspect of the present invention provides a suspension system, comprising:
         a first rocker arm having a first skate wheel connection at first distal end;   a second rocker arm having a second skate wheel connection at a second distal end;   a spring housing;   a pivoting axle connection, the pivoting axle connection pivotally connecting the first rocker arm at a first proximal end and the second rocker arm at a second proximal end, and forming a bottom of the spring housing;   the spring housing further including two lateral side walls at the first and second proximal end of the respective first and second rocker arms;   the lateral side walls include a plurality of flanges that are-aligned laterally along the lateral side walls; and   a spring comprised of polyurethane, including:   a top surface that includes two lateral edge depressions that securely abut the lip;   two lateral side surfaces that include a plurality of notches that are aligned laterally, and abut the plurality of flanges; and   a bottom surface that abuts the pivoting axle connection;   the spring contacting the first rocker arm and the second rocker arm and biasing the rocker arms so that the rocker arms counter-rotate about the pivoting axle.       

     Another aspect of the present invention provides an in-line skate wheel suspension product, the product comprising:
         a tracking system that is comprised of:   a base-support comprised of a fore plate and an aft plate coupled with a sole of a boot;   side panels extending downward from the base-support;   the side panels are spaced apart, which enable positioning a skate wheel between the side panels;   a first rocker arm disposed between the side panels;   the first rocker arm having a first skate wheel rotatably connected to the first rocker arm at a first skate wheel connection;   a second rocker arm disposed between the side panels;   the second rocker arm having a second skate wheel rotatably connected to the second rocker arm at a second skate wheel connection;   a pivoting axle, the pivoting axle pivotally connecting the first rocker arm and the second rocker arm to at least one of the tracking system side panels;   a spring, the spring positioned above the pivoting axle;   the spring positioned between the first rocker arm and the second rocker arm;   the spring having a plurality of notches, positioned laterally along an axial length of the spring, with each notch biased against a corresponding protrusion on the rocker arm;   the spring contacting the first rocker arm and the second rocker arm and biasing the rocker arms so that the rocker arms counter-rotate about the pivoting axle;   the spring contacting the first rocker arm at a position radially between the pivoting axle and the first skate wheel connection; and   the spring contacting the second rocker arm at a position radially between the pivoting axle and the second skate wheel connection.       

     These and other features, aspects, and advantages of the invention will be apparent to those skilled in the art from the following detailed description of preferred non-limiting exemplary embodiments, taken together with the drawings and the claims that follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       It is to be understood that the drawings are to be used for the purposes of exemplary illustration only and not as a definition of the limits of the invention. Throughout the disclosure, the word “exemplary” is used exclusively to mean “serving as an example, instance, or illustration.” Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. 
       Referring to the drawings in which like reference character(s) present corresponding part(s) throughout: 
         FIG. 1A , is an exemplary illustration of a prior art conventional suspension system; 
         FIGS. 1B to 1G , are exemplary illustrations of prior art polyurethane spring mechanisms; 
         FIG. 2A  is an exemplary perspective illustration of an in-line skate in accordance with the present invention; 
         FIG. 2B  is an exemplary enlarged perspective illustration of the in-line skate illustrated in  FIG. 2A , showing an assembled tracking system in accordance with the present invention; 
         FIG. 2C  is an exemplary perspective illustration of the bottom aft-section of the assembled tracking system of  FIG. 2A ; 
         FIG. 3A  is an exemplary perspective illustration of a semi-disassembled tracking system that is illustrated in  FIG. 2A , showing a first side thereof in accordance with the present invention; 
         FIG. 3B  is an exemplary perspective illustration of the tracking system that is illustrated in  FIG. 2A , showing the second side thereof; 
         FIG. 3C  is an exemplary top perspective view of the tracking system of  FIG. 2A ; 
         FIG. 3D  is an exemplary bottom perspective illustration of the tracking system of  FIG. 2A  with the fore suspension mechanism removed; 
         FIG. 3E  is an exemplary bottom perspective illustration of the tracking system of  FIG. 2A  with the fore suspension mechanism semi-assembled; 
         FIG. 3F  is an exemplary bottom perspective illustration of the tracking system of  FIG. 2A  with the fore suspension mechanism being secured thereto by a fastener mechanism; 
         FIG. 4A  is an exemplary perspective illustration of the suspension mechanism in accordance with the present invention; 
         FIG. 4B  is an exemplary lateral top perspective illustration of the suspension mechanism of  FIG. 4A ; 
         FIG. 4C  is an exemplary bottom-axial perspective view of the suspension mechanism of  FIG. 4A ; 
         FIG. 4D  is an exemplary bottom perspective view of the suspension mechanism of  FIG. 4A ; 
         FIG. 4E  is an exemplary perspective view of the suspension mechanism of  FIG. 4A , with the rocker arms semi-separated, illustrating a removable biasing mechanism and the housing for a biasing mechanism; 
         FIG. 4F  is an exemplary perspective plan view of the rocker arms and the biasing mechanism detachably coupled therein; 
         FIG. 5A  is an exemplary perspective view of the assembled rocker arms in accordance with the present invention; 
         FIG. 5B  is an exemplary perspective of semi-assembled rocker arms illustrated in  FIG. 5A ; 
         FIG. 5C  is a perspective illustration of disassembled rockers illustrated in  FIG. 5A ; 
         FIG. 6  is an exemplary illustration of a second embodiment of a suspension mechanism in accordance with the present invention; 
         FIGS. 7A to 7D  are exemplary illustration of the biasing mechanism, illustrating various top views thereof in accordance with the present invention; 
         FIGS. 8A to 8D  are exemplary illustrations of the biasing mechanism of  FIGS. 7A to 7D , illustrating the various bottom views, in accordance with the present invention; and 
         FIGS. 9A to 9C  are exemplary illustrations of various other embodiments of a biasing mechanism in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The detailed description set forth below in connection with the appended drawings is intended as a description of presently preferred embodiments of the invention and is not intended to represent the only forms in which the present invention may be constructed and or utilized. 
       FIGS. 2A to 2C  illustrate an in-line skate that includes a suspension mechanism made in accordance with the principals of the present invention.  FIG. 2A  is an exemplary perspective illustration of an in-line skate in accordance with the present invention.  FIG. 2B  is an exemplary enlarged perspective illustration of the in-line skate illustrated in  FIG. 2A , showing an assembled tracking system, and  FIG. 2C  is an exemplary perspective illustration of the bottom aft-section of the assembled tracking system in accordance with the present invention. 
     As illustrated in  FIGS. 2A to 2C , the in-line skate  200  includes a boot  202  that is configured to hold and support the foot of the wearer. The boot  202  includes a sole  230  with a tracking system  210  attached to it by a set of fasteners, non-limiting examples of which may include a set of screws  212  in the aft-plate  304 , the mid-plate  306 , and the fore-plate  308  sections ( FIG. 3A ) of the tracking system  210 . The tracking system  210  is made of any suitable material and is preferably made of plastic or aluminum. The tracking system  210  includes a series of wheels  206  rotatably attached to it so that the wheels  206  form a line. The wheels  206  are coupled with the tracking system  210  using the suspension mechanism  204  of the present invention. The suspension mechanism  204  is pivotally coupled with the tracking system  210  at a pivoting axis  310  ( FIG. 3D ) by an exemplary fastener  222 , with the wheels  206  coupled to the distal ends of the suspension mechanisms  204  by exemplary fasteners  218 . The suspension mechanism  204  allows the wheels  206  to move individually and independently relative to the boot  202  so that the in-line skate  200  can move smoothly over an uneven surface. Further, the suspension mechanism  204  maintains the wheels  206  in contact with the ground surface longer as the force from the weight of the wearer shifts, which provides increased stability. The suspension mechanism  204  further improves the maneuverability of the skates by enabling turns with shorter radius, wherein only one set of the wheels may be used to complete a turn. 
     As further illustrated in  FIGS. 2A to 2C , fasteners  226  are complementary secured at the other end by a set of exemplary nuts  222 , with the head of the fasteners  226  housed in a commensurately configured housings  224  so to prevent the rotation of the fasteners  226  during the movement of the suspension mechanism  204  while riding the skates. The fasteners  218  are also housed in respectively configured housings  220  so to prevent the rotation of the fasteners  218  during the movement of the suspension mechanism  204  while riding the skates. 
       FIGS. 3A to 3F  exemplarily illustrate the tracking system  210  in accordance with the present invention.  FIG. 3A  is an exemplary perspective illustration of a semi-disassembled tracking system that is illustrated in  FIG. 2A , showing a first side thereof; and  FIG. 3B  is an exemplary perspective illustration of the tracking system that is illustrated in  FIG. 2A , showing the second side thereof.  FIG. 3C  is an exemplary top perspective view of the tracking system of  FIG. 2A .  FIG. 3D  is an exemplary bottom perspective illustration of the tracking system of  FIG. 2A  with the fore suspension mechanism removed;  FIG. 3E  is an exemplary bottom perspective illustration of the tracking system of  FIG. 2A  with the fore suspension mechanism semi-assembled; and  FIG. 3F  is an exemplary bottom perspective illustration of the tracking system of  FIG. 2A  with the fore suspension mechanism being secured thereto by a fastener mechanism. 
     As illustrated in  FIGS. 3A to 3F , the tracking system  210  of the present invention is comprised of a base-plate  302 . The sole  230  of the boot  202  is coupled to the base plate  302  by a set of fasteners in the aft-plate  304 , the mid-plate  306 , and the fore-plate  308  sections of the tracking system  210 . The tracking system  210  is further comprised of two side panels  208 A and  208 B that enable the positioning of the suspension mechanisms  204  underneath the base-plate  302 . The two side panels  208 A and  208 B extend substantially, longitudinally along an axial length L ( FIG. 3C ) of the tacking system  210 , and further extend (or protrude) downward from the base-plate  302  to form the sides  208 A and  208 B, illustrated. The two side panels  208 A and  208 B are spaced apart laterally at varying distances D ( FIG. 3D ) along the axial length L of the tracking system  210  to allow positioning of the suspension mechanism  204  and the wheels  206  in between the side panels  208 A and  208 B. The two side panels  208 A and  208 B may also be spaced apart laterally at an equal distance along the axial length L of the tracking system. 
     As best illustrated in  FIG. 3C , the base-plate  302  of the tracking system  210  is comprised of the mid-plate section  306  that is laterally narrower than the aft-plate  304  or the fore-plate  308 , which reduces the overall mass of the tracking system  210  without loss in overall strength and ride stability. The base-plate  302  is comprised of a set of apertures  320  in both the aft-plate portion  304  and the fore-plate portion  308  for fastening the boot  202  onto the tracking system  210  via the set of exemplary fasteners  212 . Further included on the base-plate  302  is a first aperture  322  at the aft-plate portion  304  and a second aperture  326  at the fore-plate portion  308  that function as mounting holes, and are optionally used to further secure the boot  202  with the tracking system  210 . The chamber hole  324  at the mid-plate  302  is not an aperture or a through-hole, but is formed as an exemplary cylinder added as part of the bulk structures  360  for added strength. The aperture  328  between the respective mid-plate and fore-plate sections  306  and  308  is created to provide a void space to allow the front middle wheel to move into when the front middle wheel is in its maximum upward position, thereby preventing contact with the bottom side  332  of the base plate  302 . 
     As best illustrated in  FIGS. 3D to 3F , the bottom side  332  of the tracking system  210  includes the longitudinally extended two side panels  208 A and  208 B that are spaced apart laterally at varying lateral distances D ( FIG. 3D ) along the axial length L of the tracking system  210  to allow positioning of the suspension mechanism  204  and the wheels  206  in between the panels  208 A and  208 B. The two lateral sides  208 A and  208 B protrude substantially vertical from the bottom side  332  of the base-plate  302  of the tracking system  210 , and are further supported by added bulk structures  360  for added strength. The suspension mechanism  204  is pivotally coupled with the tracking system  210  at a pivoting axis  310  ( FIG. 3D ) by an exemplary fastener  226 , with the wheels  206  coupled to the distal ends of the suspension mechanisms  204  by exemplary fasteners  218 . 
       FIGS. 4A to 4F  are exemplary illustrations of the suspension mechanism  204  in accordance with the present invention. As illustrated, the suspension mechanism  204  is comprised of a set of rocker arms  214  and  216 , and a biasing mechanism  340 . The set of rocker arms includes a first rocker arm  214  having a first skate wheel connection  312  at first distal end  460 , and a second rocker arm  216  having a second skate wheel connection  314  at a second distal end  462 . The suspension mechanism  204  also includes a biasing mechanism housing  420  ( FIG. 4E ) for detachably and removably securing the biasing mechanism  340  therein. The suspension mechanism  204  includes a pivoting axis  310  and a pivoting axle connection  318 , the pivoting axle connection  318  pivotally connecting the first rocker arm  214  at a first proximal end  464  and the second rocker arm  216  at a second proximal end  466 . The pivot axle connection  318  further couples the rocker arms to the tracking system  210 , and forms a bottom  500  ( FIG. 5A ) of the biasing mechanism housing  420 . 
     As illustrated in  FIGS. 4A and 4B , during the ride of the in-line skate  200 , when encountering an uneven surface, the wheels  206  coupled at the distal ends  460  and  462  of the respective rocker arms  214  and  216  move along the substantially vertical reciprocating path  450 , pushing the respective proximal ends  464  and  466  along the substantially horizontal reciprocating path  452  (along the axial length  460  of the suspension mechanism  204 ). Stated otherwise, top sections  402  and  404  of the respective rocker arms  216  and  214  will move in the direction of the reciprocating path  452 , pressing against the biasing mechanism  340 , while the distal ends  460  and  462  move along the vertical reciprocating path  450 . The combined rocker arms  214  and  216  move pivotally along the reciprocating paths  408  and  410 , pivoting along the pivot axis  310 . As illustrated, in response to the applied compression by the rocker arms  214  and  216 , the biasing mechanism  340  is deformed in the direction indicated by the vertical arrow referenced  414 , which provides a spring action for the wheels. As best illustrated in  FIGS. 4C and 4D , the suspension mechanism  204  includes a curved-in section  470  to accommodate a set of wheels  206  so to allow the wheels  206  to rotate without contacting the body of the rocker arms  214  and  216 . 
     As best illustrated in  FIGS. 4E and 4F , the biasing mechanism  340  (in the form of a polyurethane spring) is configured to mate with the biasing mechanism housing  420 , forming the suspension mechanism  204  of the present invention. As illustrated, the biasing mechanism  340  includes two lateral side surfaces that include a plurality of vertically oriented notches  426  that are aligned laterally, and abut the plurality of vertically oriented flanges  422  of the biasing mechanism housing  420 . A bottom surface  802  ( FIG. 8A ) of the biasing mechanism  340  abuts the pivoting axle connection. It should be noted that the entire described structure of the biasing mechanism  340  and the biasing mechanism housing  420  can be reversed (upside-down) or inversed. That is, the top of the biasing mechanism  340  can be contained within the biasing mechanism housing  420 , and the bottom  802  thereof can abut the top  402  and  404  of the biasing mechanism housing  420 . One non-limiting important factor is to contain the biasing mechanism  340 , and allow for one free side (longitudinally) of the biasing mechanism  340  for depression and or expansion thereof against pressure or forces from the rocker arms. The biasing mechanism  340  contacts the first rocker arm  214  and the second rocker arm  216  and biases the rocker arms so that the rocker arms counter-rotate about the pivoting axle, against applied forces due to ride on uneven surface areas. 
       FIGS. 5A to 5C  are exemplary illustrations of the rocker arms, including the biasing mechanism housing in accordance with the present invention. As illustrated in  FIGS. 5A to 5C , the rocker arms  214  and  216  are comprised of a set of pivot knuckles  502 ,  504 ,  506 , and  508  that form the pivoting axis  310  in the form of pivoting axle connections  318  and  440  for each rocker arm, allowing the rocker arms  214  and  216  to pivot about the pivoting axis  310 . The respective first and second proximal end  464  and  466  of the respective first and second rocker arms  214  and  216  form the two lateral side walls  490  and  492  of the biasing mechanism housing  420 . The vertically oriented lateral side walls  490  and  492  include a plurality of vertically oriented flanges  422  that are aligned laterally along the lateral side walls  490  and  492 . The biasing mechanism housing  420  also includes a top  402  and  404  at the first and second proximal end  464  and  466  having a length that extends longitudinally along an axial width W of the set of rocker arms and a width forming a lip  432  and  434 . A top surface  450  of the biasing mechanism  340  includes two lateral edge depressions  442  that securely abut the lip  432  and  434  of the biasing mechanism housing  420 . 
       FIG. 6  is an exemplary illustrations of a second embodiment of a suspension mechanism  604  in accordance with the present invention. The suspension mechanism  604  includes similar corresponding or equivalent components as the suspension mechanism  204  that is shown in  FIGS. 2A to 5C , and described above. Therefore, for the sake of brevity, clarity, convenience, and to avoid duplication, the general description of  FIG. 6  will not repeat every corresponding or equivalent component that has already been described above in relation to the suspension mechanism  204  that is shown in  FIGS. 2A to 5C . 
     As illustrated, the suspension mechanism  604  includes a first rocker arm  214  that is shorter than a second rocker arm  616 . In general, it is preferred that the suspension mechanism  604  be coupled with the tracking system  210  in such manner that allows the second, longer rocker arm  616  to be positioned at the distal ends of the tracking system  210 . In other words, it is preferred that the first and the last wheels  206  of the in-line skate (at the extremities—most distal ends of the tracking system  210 ) be coupled to the longer rocker arm  616 . However, the suspension mechanism  604  may be oriented along the tracking system  210  at any position. This will provide a greater flexibility in the selection of wheel size and wheel placement along the tracking system  210 . 
       FIGS. 7A to 7D  are exemplary illustration of the biasing mechanism, illustrating various top views thereof, and  FIGS. 8A to 8D  are exemplary illustrations of the biasing mechanism of  FIGS. 7A to 7D , illustrating various the bottom views, all in accordance with the present invention. As illustrated, the polyurethane biasing mechanism  340  is comprised of a first surface contact area  428  with a first mass having a durometer that provides a first resistance and a first rate of resistance responsive to application of forces. It further includes a second surface contact area  426  with a second mass having the same durometer that provides a second resistance and a second rate of resistance responsive to the forces, with the first resistance and the first rate of resistance different from the second resistance and second rate of resistance, a combination of which provides a rate of resistance that commensurately varies and is correspondingly responsive in relation to varying forces. In other words, a method for varying a resistive response and resistive rate of response of a polyurethane is provided by the present invention by increasing its contact surface area and lowering its mass. 
     The polyurethane material biasing mechanism  340  has an axial length L, a width W, and a depth (or thickness) T. Its top surface  450  includes slightly concaved section or depression that is extended longitudinally, along the axial length L thereof, with the slightly concaved section including lateral edge depressions  442  extending longitudinally, along the axial length L of the biasing mechanism  340 . 
     As further illustrated, the polyurethane material biasing mechanism  340  further includes two lateral side surfaces with periphery that is curved forming a radial protuberance  428 , and extending longitudinally along the axial length L of the basing mechanism  340 . The curved forming radial protuberance  428  of the lateral surfaces may be flat or any form, including concaved or convex. The lateral side surfaces further include a plurality of vertically oriented notches  426  that are formed into the curved protuberance  428  of the lateral side surfaces of the biasing mechanism  340 . The notches  426  are aligned laterally along the axial length L of the biasing mechanism  340 , forming an alternating notch  426  and protuberance  428 . Each notch  426  of the plurality of notches is comprised of a substantially flat base  720 , with the curved protuberances forming two side walls of each notch  426 . The flat base  720  extends from the top surface  450  to a bottom surface  802  of the biasing mechanism  340 , and substantially perpendicular to the interior two side walls that form the notch. The biasing mechanism  340  further includes a bottom surface  802  having a respective first and second distal ends  804  and  806  that are substantially flat, and a center portion  803  that is slightly convex extending longitudinally along the axial length L of the basing mechanism  340  between the respective first and second distal ends  804  and  806 . It should be noted that the bottom surface  802  can vary in form to match the biasing mechanism housing  420 . 
     As illustrated, the above described structure of the biasing mechanism  340  and the accommodating biasing mechanism housing  420  of the rocker arms  214  and  216  increase the overall contact surface area while reducing the overall mass of the biasing mechanism  340 . The structural arrangement provides a wide range of resistance to accommodate a smooth ride against the application of different forces and, more particularly, provides a rate of resistance that commensurately varies and is correspondingly responsive in relation to shifting of user weight during the ride of the in-line skates, without requiring any adjustments. In addition, the structure of the suspension mechanism  204  of the present invention is simple and does not require user meddling for adjustment of resistance and rate of resistance of the biasing mechanism  340 . 
     The overall contact surface area of the biasing mechanism  340  is increased by providing the notches and the curved protrusion along the lateral side walls thereof. The overall mass of the biasing mechanism is decreased by removing material form the lateral side walls to create the notches. The overall increase in contact surface area and decrease in polyurethane mass provides for a biasing mechanism that has a greater overall wider range of resistance against the application of different forces and, more particularly, wider range of rate of resistance that commensurately varies and is correspondingly responsive in relation to shifting of user weights during the ride of the in-line skates. 
     In particular, the contact point surface area of the base  720  of the notches  426  has an overall less polyurethane mass than at the protuberances of the lateral side walls  428 . In general, the smaller the mass of the polyurethane is, the greater its stiffness (higher resistance against deformation under compressive forces). These sections (notches  426 , with their base  720 ) have a greater degree of resistance against an applied pressure or force due to less mass and therefore, require a higher level of compression (forces) to deform. In other words, the contact points (the base  720 ) respond with different resistance and rate of resistance against an application of force, compared to the protuberances  428  (with higher level of polyurethane mass). The protuberances  428  (with higher polyurethane mass) have a lesser degree of resistance and therefore, would deform quicker against a smaller force (compression). For quicker response rate (of resistance), the base  720  and the interior lateral side walls forming the walls of the notches  426  are preferably formed at a substantially  90  degree angle, providing the least mass with highest level of contact surface area. 
     The curved protuberance area  428  of the biasing mechanism  340  increases the contact surface area between the biasing mechanism  340  and the rocker arm housing  420 , while the notches  426  reduce the overall mass of the biasing mechanism. When compressed by the rocker arms, the top concaved portion  450  of the biasing mechanism  340  becomes convex, and hence, under pressure, the biasing mechanism  340  must first overcome the concaved curve resistance, providing greater resistive characteristics. The concaved configuration further removes more mass from the biasing mechanism  340 , lowering its overall mass to increase its stiffness while increasing surface area. In addition, the thin edge  442  mating with the lip  432  and  434  of the rocker arms top  402  and  404 , decreases overall mass to increase resistance and further, increases contact area. 
       FIGS. 9A to 9C  are exemplary illustrations of various other embodiments of a biasing mechanism in accordance with the present invention. The biasing mechanisms  902 ,  910 , and  914  include similar corresponding or equivalent components as the biasing mechanism  340  that is shown in  FIGS. 2A to 8D , and described above. Therefore, for the sake of brevity, clarity, convenience, and to avoid duplication, the general description of  FIGS. 9A to 9C  will not repeat every corresponding or equivalent component that has already been described above in relation to the biasing mechanism  340  that is shown in  FIGS. 2A to 8D . 
     As illustrated, the polyurethane biasing mechanisms  902 ,  910 , and  920  are comprised of a respective first surface contact area  904 ,  912 , and  916  with a first mass having a durometer that provides a first resistance and a first rate of resistance responsive to application of forces. They further include a second surface contact area  906 ,  914 , and  918  with a second mass having the same durometer that provides a second resistance and a second rate of resistance responsive to the forces. As with the biasing mechanism  340 , the first resistance and the first rate of resistance for the biasing mechanism  902 ,  910 , and  920  are different from the second resistance and second rate of resistance, a combination of which provides a rate of resistance that commensurately varies and is correspondingly responsive in relation to varying forces. In other words, a method for varying a resistive response and resistive rate of response of a polyurethane is provided by the present invention by increasing its contact surface area and lowering its overall mass, regardless of orientation of notches. Of course, the orientation of the flanges of the biasing mechanism housing of the rocker arms must commensurate with the orientation of the notches on the biasing mechanism so to house and accommodate the biasing mechanisms. In other words, for example, the horizontally oriented set of notches  914  of the biasing mechanism  910  illustrated in  FIG. 9B , would require a biasing mechanism housing that has a corresponding set of horizontally oriented flanges. The same may be said for the biasing mechanisms  902  and  920 . 
     Although the invention has been described in considerable detail in language specific to structural features and or method acts, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as preferred forms of implementing the claimed invention. Stated otherwise, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. Therefore, while exemplary illustrative embodiments of the invention have been described, numerous variations and alternative embodiments will occur to those skilled in the art. For example, the top  402  and  404  with the lip  432  and  434  are optional, it is only used to secure the biasing mechanism  340  that have vertical notches. Biasing mechanisms with notches having horizontal or other orientations do not require a top. Such variations and alternate embodiments are contemplated, and can be made without departing from the spirit and scope of the invention. 
     It should further be noted that throughout the entire disclosure, the labels such as left, right, front, back, top, bottom, forward, reverse, clockwise, counter clockwise, up, down, or other similar terms such as upper, lower, aft, fore, vertical, horizontal, proximal, distal, etc. have been used for convenience purposes only and are not intended to imply any particular fixed direction or orientation. Instead, they are used to reflect relative locations and/or directions/orientations between various portions of an object. 
     In addition, reference to “first,” “second,” “third,” and etc. members throughout the disclosure (and in particular, claims) is not used to show a serial or numerical limitation but instead is used to distinguish or identify the various members of the group. 
     In addition, any element in a claim that does not explicitly state “means for” performing a specified function, or “step for” performing a specific function, is not to be interpreted as a “means” or “step” clause as specified in 35 U.S.C. Section 112, Paragraph 6. In particular, the use of “step of,” “act of,” “operation of,” or “operational act of” in the claims herein is not intended to invoke the provisions of 35 U.S.C. 112, Paragraph 6.