PATENT ABSTRACT
A braking device is provided for an in-line skate where the braking device selectively alters the motion of the in-line skate depending upon the angulation of the in-line skate relative to a surface. As a user angulates or tilts the in-line skate, the braking device increasingly engages the surface to provide a braking force to alter the motion of the in-line skate.

PATENT DESCRIPTION
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 61/780,181, filed Mar. 13, 2013, which is incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     Embodiments of the present invention are generally related to a braking device used to selectively alter the speed of an individual wearing in-line skates. 
     BACKGROUND OF THE INVENTION 
     In-line skates comprise boot portion for receipt of the user&#39;s foot. A wheel frame, which supports at least two tandem wheels, is interconnected to a lower surface of the boot. In-line skates have become popular recreational equipment and are often used as an alternative to roller skates. Furthermore, in-line skates are preferred by floor or roller hockey enthusiasts who seek an ice hockey experience. However, many players find it difficult to slow and stop in the same manner and fashion as experienced in ice skating when wearing in-line skates. 
     Most in-line skates employ a brake pad on the aft end of the frame and/or boot. To stop, the user tilts his or her toe upwardly, which rotates the boot about the rearmost wheel and places the brake pad in contact with the ground. As one of skill in the art will appreciate, pad-to-ground contact generates a friction load that slows and eventually stops forward motion. Brake pads work well to stop forward motion, but cannot slow or stop a user when his or her boots are moving laterally, i.e., when attempting to make a turning stop often performed while playing ice hockey, or participating in other in-line skate activities. Further, using such brakes is awkward as the user must shift his or her body weight rearwardly in such a way to place the pad in contact with the ground. Over-rotation will cause the user to fall, which could cause serious injury. 
     To address this latter issue, some in-line skates employ handbrakes similar to those used in bicycles that comprise a pad that contacts a portion of at least one wheel of the in-line skate. For example, U.S. Published Patent Application No. 2004/0207163 to Smyler discloses a handbrake that contacts a rear wheel to reduce the forward velocity. The system is unusable for floor or roller hockey players because they require both hands to hold a hockey stick. 
     Other in-line skates employ disc brakes as disclosed in WIPO Publication No. 2008/082675 to Lin, which discloses a device that includes a mechanism that interconnects above the user&#39;s ankle wherein the user must tilt rearwardly to actuate the brake. These devices suffer the same drawbacks of over-rotation and potential injury described above. Still other in-line skates include a toe-actuated brake as disclosed in U.S. Pat. No. 5,143,387 to Colla. These braking devices add complexity and cost to the in-line skate and are not intuitive to use, especially to those who are accustomed to slowing or stopping as they do when using ice skates. 
     It is a long felt need to provide an in-line skate braking device that allows for ease of braking while not adding complexity to the in-line skate or by requiring the user to use his or her hands. The following disclosure describes an improved braking device that allows the user to slow and stop while turning as commonly performed by ice hockey players, and to make in-line skating safer and more enjoyable for other enthusiasts. 
     SUMMARY OF THE INVENTION 
     It is one aspect of embodiments of the present invention to provide an in-line skate braking device that generates braking force dependant on degree of lateral tilt or change in orientation. This aspect of the present invention is desirable to individuals who play floor hockey, roller hockey, or participate other in-line skate activities because braking force is not dependent on the distance between the skate heel or tip and the ground. 
     It is thus another aspect of embodiments of the present invention to provide an in-line skate brake that allows the in-line skate to slow or stop much like an ice skate wherein the amount of ice skate lateral deflection dictates the applied braking force. Braking while laterally tilting the in-line skate more accurately simulates ice-skating where the degree of turn dictates the generated force that impedes forward motion of the skate and the user. Thus, individuals playing floor hockey, roller hockey, or participating in other in-line skate activities will have a more realistic experience. Individuals who play ice hockey can use the in-line skate and braking apparatus as contemplated herein for training purposes and not have to adjust their normal play to account for alternative braking methods employed by existing in-line skates. In addition, the realistic slowing and stopping options provided to all users will increase user safety and enjoyment. 
     It is an aspect of embodiments of the present invention to provide a braking force that increases as a user progressively engages a braking device. More specifically, the braking device of one embodiment comprises a housing or receiver interconnected to a brake frame that accommodates a plurality of spring-loaded balls that selectively contact the ground when the in-line skate is tilted laterally a predetermined amount. The amount of skate tilt will dictate the normal force the ball applies to the ground and, thus, the applied frictional braking force. The ball may rotate within the housing or fixed relative thereto. 
     It is yet another aspect of the present invention to provide braking device that includes replaceable elements. To provide maximum braking force, some embodiments of the present invention employ a ball that rotates to some degree which will cause it to wear over time. When the ball, or other friction-producing member, wears, it can be quickly and easily replaced by removing a retainer that secures the components of the braking device to the slider receiver. Further, if a user desires to upgrade components of the present invention or replace worn-out parts, the parts may be easily replaced. 
     It is yet another aspect of some embodiments of the present invention to provide a fully adjustable braking device to suit different user preferences and skill levels. Adjustable aspects of the braking device include, but are not limited to, modification of the angle of the braking device from a vertical plane, the distance that the braking device extends from the frame or in-line skate, and whether the brake force responds linearly, non-linearly, or otherwise from the user&#39;s input, i.e., tilting of the braking device into a surface. Further, a user may arrange the braking devices in various configurations. In some embodiments, the braking devices are arrayed on either side of an in-line skate frame. Alternative embodiments may allow a user to selectively remove and replace braking devices such that one side of the in-line skate has one or more braking devices, and the other side may have no braking devices. 
     It is one aspect of embodiments of the present invention to provide an in-line skate assembly, comprising: a frame having a plurality of receivers each having a proximate end and a distal end; a spring cap positioned in each of the plurality of receivers at the proximate end of each receiver; a sliding collar positioned in each of the plurality of receivers, wherein an outwardly extending flange is disposed on a proximate surface on each of the sliding collars, and wherein a distal surface on each of the sliding collars includes an aperture; a ball positioned in each of the sliding collars, wherein at least a portion of the ball is exposed through the aperture on each of the sliding collars; a locator disk positioned within each of the sliding collars and located on a side of the ball opposite the aperture on each of the sliding collars; a spring positioned in each of the plurality of receivers, the spring having a first end and a second end, wherein the first end of the spring interfaces with each the spring cap, wherein the spring extends into the sliding collar, and wherein the second end of the spring interfaces with the locator disk such that the spring exerts a force on the locator disk, which in turn exerts a frictional force on the ball, which biases a portion the ball against the distal surface of the sliding collar; a retainer with an inwardly extending flange on a distal surface of the retainer, wherein the retainer operatively interconnects to each of the plurality of receivers; wherein each of the sliding collars has a first position of use wherein the inwardly extending flange of the retainer is selectively engaged with the outward extending flange of the sliding collar; and wherein each of the sliding collars has a second position of use wherein the ball is in contact with a surface and the ball is forced into each of the plurality of receivers. 
     It is still yet another aspect of embodiments of the present invention to provide a braking device for interconnection to an in-line skate, comprising: a slider receiver having an inner diameter, a proximate end, and a distal end; a slider partially disposed in the slider receiver, the slider having an outer diameter that is less than the inner diameter of the slider receiver; a ball partially disposed in the slider, the ball having a diameter that is less than the outer diameter of the slider; and a biasing device having a first end and a second end, wherein the first end of the biasing device interfaces with the proximate end of the slider receiver, and wherein the second end of the biasing device is operatively interconnected with the ball. 
     It is a further aspect of embodiments of the present invention to provide an in-line skate assembly, comprising: a frame having a plurality of receivers having a proximate end and a distal end, the distal end of each of the plurality of receivers having an inwardly facing flange that forms an aperture; a first friction-generating means disposed in each of the plurality of receivers at the distal end of the receivers, wherein at least a portion of the first friction-generating means is exposed through the aperture of the inwardly facing flange of each of the plurality of receivers; and a biasing means disposed between the proximate end of each of the plurality of receivers and the first friction-generating means of each of the plurality of receivers, wherein the biasing means produces a force against the first friction-generating means of each of the plurality of receivers. 
     The Summary of the Invention is neither intended nor should it be construed as representing the full extent and scope of the present invention. Moreover, references made herein to “the present invention” or aspects thereof should be understood to mean certain embodiments of the present invention and should not be construed as limiting all embodiments to a particular description. The present invention is set forth in various levels of detail in the Summary of the Invention and in the attached drawings and the Detailed Description of the Invention and no limitation as to the scope of the present invention is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary of the Invention. Additional aspects of the present invention will become more readily apparent from the Detail Description, particularly when taken with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and with the general description of the invention given above and the detailed description of the drawings given below, explain the principles of these inventions. 
         FIG. 1  is an isometric, exploded view of a braking device of one embodiment of the present invention; 
         FIG. 2A  is a front elevation view of a frame with a shield in accordance with embodiments of the present invention; 
         FIG. 2B  is a side elevation view of the frame and shield of the embodiment in  FIG. 2A ; 
         FIG. 2C  is a top plan view of the frame and shield of the embodiment in  FIG. 2A ; 
         FIG. 3  is a front elevation view of a frame and braking device of one embodiment of the present invention; 
         FIG. 4  is a front elevation view of the frame and braking device of  FIG. 3  where a friction-generating element is biased into the frame; 
         FIG. 5A  is an isometric view of a frame and braking device with spring cap pairs; 
         FIG. 5B  is an isometric view of a spring cap assembly; 
         FIG. 6  is a bottom isometric view of a frame of one embodiment of the present invention; 
         FIG. 7  is an isometric view of a frame with a side shield in accordance with some embodiments of the present invention; 
         FIG. 8A  is an isometric, exploded view of a braking device of one embodiment of the present invention; 
         FIG. 8B  is a cross-sectional view of a braking device of one embodiment of the present invention; 
         FIG. 9A  is a side elevation view components of a braking device of one embodiment of the present invention; 
         FIG. 9B  is a side isometric view of a frame with the braking device components of the embodiment in  FIG. 9A ; 
         FIG. 9C  is an isometric view of the frame and braking device of the embodiment in  FIG. 9B ; 
         FIG. 10A  is a front elevation view of a frame of one embodiment of the present invention; 
         FIG. 10B  is a top plan view of the frame of the embodiment in  FIG. 10A ; 
         FIG. 10C  is a side elevation view of the frame of the embodiment in  FIG. 10  A; 
         FIG. 11A  is an isometric view of the frame of the embodiment in  FIG. 10A ; 
         FIG. 11B  is a side view of the frame of the embodiment in  FIG. 10A ; and 
         FIG. 11C  is a top view of the frame of the embodiment in  FIG. 10A . 
     
    
    
     To assist in the understanding of the embodiments of the present invention the following list of components and associated numbering found in the drawings is provided herein: 
     
       
         
               
               
             
               
               
             
           
               
                   
               
               
                 No. 
                 Component 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 90 
                 Boot 
               
               
                 100 
                 Braking Device 
               
               
                 102 
                 Frame 
               
               
                 104 
                 First Wheel 
               
               
                 105 
                 Second Wheel 
               
               
                 106 
                 Third Wheel 
               
               
                 107 
                 Fourth Wheel 
               
               
                 108 
                 Slider 
               
               
                 112 
                 Ball 
               
               
                 114 
                 Base Opening 
               
               
                 116 
                 Spring Cap 
               
               
                 120 
                 Spring Cap Assembly 
               
               
                 124 
                 Cross Rib 
               
               
                 128 
                 Wheel Axle Aperture 
               
               
                 130 
                 Wheel Axle 
               
               
                 132 
                 Slider Receiver 
               
               
                 136 
                 Side Shield 
               
               
                 140 
                 Spring 
               
               
                 144 
                 Locator Disk 
               
               
                 148 
                 Sliding Collar 
               
               
                 152 
                 Retainer 
               
               
                 156 
                 Pad 
               
               
                 160 
                 Spring Spacer 
               
               
                 164 
                 Shield 
               
               
                 168 
                 Shield Width 
               
               
                 172 
                 Shield Height 
               
               
                 176 
                 Wheel-to-Wheel Length 
               
               
                 177 
                 Horizontal Extension 
               
               
                 178 
                 First Vertical Extension 
               
               
                 179 
                 Second Vertical Extension 
               
               
                 180 
                 Vertical Extension Thickness 
               
               
                 184 
                 Vertical Extension Gap 
               
               
                 188 
                 Horizontal Extension Thickness 
               
               
                 192 
                 Receiver Rib Thickness 
               
               
                 196 
                 Receiver Angle 
               
               
                 200 
                 Receiver Radius 
               
               
                 204 
                 Base Opening Length 
               
               
                 208 
                 Base Opening First Width 
               
               
                 212 
                 Horizontal Extension Width 
               
               
                 216 
                 Base Opening Radius 
               
               
                 220 
                 First Base Opening Distance 
               
               
                 224 
                 Second Base Opening Distance 
               
               
                 228 
                 Third Base Opening Distance 
               
               
                 232 
                 Horizontal Extension Length 
               
               
                 236 
                 Vertical Extension Radius 
               
               
                 240 
                 Vertical Extension Angle 
               
               
                 244 
                 First Radius Length 
               
               
                 248 
                 First Wheel Aperture Length 
               
               
                 252 
                 Second Wheel Aperture Length 
               
               
                 256 
                 Third Wheel Aperture Length 
               
               
                 260 
                 Fourth Wheel Aperture Length 
               
               
                 264 
                 Second Radius Length 
               
               
                 268 
                 Receiver Width 
               
               
                 272 
                 First Receiver Diameter 
               
               
                 276 
                 Second Receiver Diameter 
               
               
                 280 
                 Notch Height 
               
               
                 284 
                 First Receiver Radius 
               
               
                 288 
                 Receiver Rib Width 
               
               
                 292 
                 Third Receiver Diameter 
               
               
                   
               
             
          
         
       
     
     It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood that the invention is not necessarily limited to the particular embodiments illustrated herein. 
     DETAILED DESCRIPTION 
     As described below, various embodiments of the present invention include a braking device  100  that provides a force used to generate braking friction. Embodiments of the present invention have significant benefits across a broad spectrum of endeavors. It is the Applicant&#39;s intent that this specification and the claims to be accorded a breadth in keeping with the scope and spirit of the described invention or inventions despite what might appear to be limiting language imposed by referring to specific disclosed examples. 
       FIG. 1  is an isometric view of one embodiment of the present invention where a boot  90  is interconnected to a shield  164 , and various braking devices are shown in an exploded view. A user wears the boot  90  on his or her foot, and when a user tilts the boot  90  to either side, a friction-generating element or biasing device, a ball  112  in this embodiment, engages the surface to rotate the ball  112  and generate braking force. The braking devices in  FIG. 1  comprise a slider receiver  132  disposed in the frame, a spring  140 , a sliding collar  148 , the ball  112 , and a retainer  152 . However, the embodiment in  FIG. 1  also comprises a pad  156  and a spring spacer  160 . The pad  156  provides a surface upon which the spring  140  can press against, and the pad  156  translates the spring force to the ball  112 . As the ball  112  rotates against the pad, friction is generated that influences ball rotation which creates a braking friction between the ball and the surface that slows or stops longitudinal movement of the skate. The friction produced at the ball/pad interface is influenced by the spring stiffness, the pad material, the pad shape and configuration, the pad surface configuration, the ball material, the ball surface configuration, etc. Also, the pad may include an indent or pocket that receives the ball, which acts as a dynamic joint and increases contact between the ball and the pad. Accordingly, embodiments allow for the replacement of the ball, spring, and pad so that stopping characteristics can by selectively tailored to meet the user&#39;s needs. The spring spacer  160  is disposed in the slider receiver  132  and provides a surface upon which the spring  140  can press against. 
       FIG. 1  also shows other components of the present invention. A wheel axle  130  may be positioned in wheel axle apertures (shown in  FIG. 6 ) to provide an axis upon which wheels may rotate. Further in this embodiment, a shield  164  interfaces with the top of the frame. 
       FIGS. 2A-2C  show various views of the frame and the braking devices with the shield affixed to the frame.  FIG. 2A  is a front elevation view of the frame and shield assembly. The shield width  168  in this embodiment is approximately 4.6″. Further, the shield height  172 , or the distance between the bottom of the wheels and the top of the shield, is approximately 4.5″.  FIG. 2B  shows a side elevation view of the frame and shield assembly, which comprises four wheels: a first wheel  104 , a second wheel  105 , a third wheel  106 , and a fourth wheel  107 . In this embodiment of the present invention, the first wheel  104  is approximately 72 mm in diameter, the second wheel  105  is approximately 76 mm in diameter, the third wheel  106  is approximately 76 mm in diameter, and the fourth wheel  107  is approximately 80 mm in diameter. These wheel sizes provide the user with a forward-leaning stance. One skilled in the art will appreciate other sequences of wheel sizes that are advantageous. For example, embodiments may have wheels that are the same size or that are larger towards the front end of the frame.  FIG. 2C  shows a top plan view of the shield and frame assembly. 
       FIGS. 3 and 4  show an embodiment of the present invention where braking devices  100  engage a surface to rotate a ball  112  and generate braking friction, which may be dependent on the amount of ball rotation.  FIG. 3  shows the frame  102  tilted at from a vertical plane wherein a first wheel  104  is visible. A slider  108  is partially disposed in the frame  102 , and the ball  112  is partially disposed in the slider  108 . The slider  108  and the ball  112  extend outwardly at an angle relative to a plane through the longitudinal axis of the frame  102 . The slider  108  and the ball  112  are forced outward by a spring. The braking device  100  in  FIG. 3  is shown initially engaged because the ball  112  has just contacted the surface. 
       FIG. 4  shows the braking device  100  fully engaged. When the user tilts the frame  102  the ball  112  will initially contact with the ground. Further rotation will force the ball  112  upward into the frame  102 , which will compress a spring positioned between the slider  108  and the frame  102 . As the spring is compressed, the force exerted on the ball  112  will increase, thereby increasing the normal load imparted on the ground by the ball  112 . As one skilled the art will appreciate, the greater the normal load, the greater the friction generated by the ball  112 . Eventually, the slider  108  will be substantially positioned within the frame  102  wherein additional lateral rotation will increase the normal load to the ball  112  to affect maximum braking. When the frame  102  is rotated laterally in an opposite direction, force on the ball  112  and friction will decrease proportionately, which reduces the braking force. When the frame  102  is rotated a predetermined amount, the spring will expand and the ball  112  will be positioned away from the frame  102  and away from the ground. 
     In the embodiment depicted in  FIGS. 3 and 4 , the ball  112  may be 1″ or 25 mm in diameter. However, one skilled in the art will appreciate embodiments of the present invention employ balls  112  of other sizes, and the balls  112  used in the same frame  100  do not have to be the same size. Further, in some embodiments, the ball  112  may freely rotate inside of the slider  108 . In this instance, the ball  112  generates less braking force. In other embodiments of the present invention, the ball  112  may have a stifled or slowed rotation so the ball  112  generates a greater braking force. The ball  112  may generate different friction forces depending on various characteristics of the ball  112  such as, but not limited to, durometer hardness, other indicators of hardness, compressive strength, ductility, grain size, and crystalline structure. 
       FIGS. 3 and 4  show an embodiment of the present invention that has a slider  108  which is not confined to the braking device  100  with a separate retainer. Rather, the slider  108  comprises a flange disposed at a proximate end of the slider  108  that prevents the spring from pushing the slider  108  out of the braking device  100 . Other embodiments, discussed in greater detail below, comprise a separate retainer that prevents the spring from pushing the slider  108  out of the braking device  100 . 
     In further embodiments of the present invention, a slider  108  is not included. The distal end of the slider receiver portion of the frame  100  that houses the braking device may comprise an inwardly extending flange or an aperture such that a portion of the ball  112  is exposed through the flange or aperture to engage a surface. The spring pushes the ball  112  against the flange or aperture and function similar to other embodiments described herein. 
       FIGS. 5A and 5B  show the braking device  100  and three spring cap pairs  116  above the frame  102 . This embodiment comprises a frame  102  and a series of braking devices  100  comprising of sliders  108  and balls  112 . The three spring cap pairs  116  provide a location upon which a spring may press against. The base openings  114 , which the spring cap pairs  116  are disposed, allow the frame  102  to mount into another device  100 , typically an in-line boot.  FIG. 5B  shows a spring cap assembly  120  where the spring cap pairs  116  are configured into a single piece. 
       FIG. 6  shows a bottom isometric view of an embodiment of the present invention. Here, six slider receivers  132  disposed on the frame  102 , with three slider receivers  132  disposed on one side of the frame  102 , and three slider receivers  132  disposed on the opposite side of the frame  102 . The two arrays of slider receivers  132  may exhibit bilateral symmetry about a plane through the longitudinal axis of, and perpendicular to the top surface of, the frame  102 . Cross ribs  124  are disposed between the slider receivers  132  to add rigidity to the frame  102 . 
     Also shown in  FIG. 6  are a series of wheel axle apertures  128  where wheels and wheel axles may be located. The wheel axle apertures  128  are spaced along the longitudinal length of the frame  102  such that the slider receivers  132  may be disposed between each wheel axle aperture  128 . 
     In the embodiment shown in  FIG. 6 , the frame  102  is made from cast aluminum which is light weight and strong. However, other materials may be used, such as, but not limited to, carbon fiber, pressed aluminum, polyurethane, or magnesium. 
       FIG. 7  shows another embodiment of the present invention that comprises a side shield  136  that extends from the top of the frame  102  towards the braking device balls. The side shield  136  acts as a governor when the user tilts the frame  102  and engages the braking device on a surface. As the balls are pressed into the frame  102 , the shield will stop the travel of the balls at a certain point during operation of the braking device. This governing of the braking device prevents the ball and slider assemblies from locking up and damaging the braking device. As such, the side shield  136  may be made of a friction producing material. The side shield  136  may also be compliant so not to damage the playing surface when contact is made. Further, the side shield  136  provides protection so pucks or balls impacting the skate do not damage the braking devices. In addition, the side shield  136  prevents entanglement between the braking devices of the user&#39;s left and right skates as well as between the user&#39;s skates and a third party&#39;s skates. The side shields  136  may be removable. 
       FIGS. 8A and 8B  show a retainer  152  used to secure the sliding collar  148  and prevent the spring  140  from pushing the sliding collar  148  out of the braking device  100 . The frame  102  accommodates a slider receiver  132 , which is an opening or cavity that houses components of the braking device  100 . A spring  140  is partially disposed in the slider receiver  132 . The spring  140  size and stiffness may be altered to suit player needs or desires. The springs may also be different where the braking devices provide different braking characteristics. As the ball  112  is pressed into the frame  102 , specifically the slider receiver  132 , the spring  140  compresses and provides an increasing force against a locator disk  144 , and in turn, an increasing force against the ball  112 . The locater disk  144  helps the spring  140  align with the ball  112  and allows the ball  112  to rotate, or not rotate, as the braking device  100  is engaged. 
     More specifically, the frictional interaction between the ball  112  and the locater disk  144  may dictate the braking force of the braking device. The locator disk  144  comprises an indentation to provide more surface area contact with the ball  112 . The locator disk  144  can be made from a variety of materials with a number of features that determine the friction generated between the locator disk  144  and the ball  112 . For example, the locator disk  144  may comprise a textured or coarse surface that generates a high amount of frictional force with the ball  112 . A user may desire to change the locator disk  144  and/or ball  112  to set up different performance characteristics of the braking device  100 . 
     The sliding collar  148  and the retainer  152  are disposed on the end of the braking device  100 . The sliding collar  148  comprises an aperture on its bottom edge or distal surface, teeth on its outer surface, and a flange on its top edge or proximate surface. The aperture allows the ball  112  to extend out from the braking device  100 , but the aperture does not allow the ball  112  to fall out. This means the diameter of the aperture is less than or equal to the diameter of the ball  112 . The teeth on out the outer surface of the sliding collar  148  correspond to teeth on the retainer  152  which prevents rotation of the sliding collar  148  as the user engages the braking device  100 . The flange on the proximate surface of the sliding collar  148  extends outward in the radial direction to provide a surface upon which the retainer  152  can secure the sliding collar  148 . 
     The retainer  152  comprises teeth on its inner diameter, threads on its outer surface, and an inward facing flange located proximate the teeth on the inner surface. The teeth correspond to the teeth on the outer surface of the sliding collar  148  which prevents rotation of the sliding collar  148  when a user engages the braking device  100 . The inward facing flange of the retainer  152  is also located towards the same distal end of the retainer  152  as the teeth. The inward facing flange corresponds to the flange of the sliding collar  148  such that the inner diameter of the inward facing flange is equal to or less than the outer diameter of the flange of the sliding collar  148 . This allows the two flanges to selectively engage such that the retainer  152  secures the sliding collar  148  to prevent the danger of the sliding collar  148  falling out of the braking device  100 . The retainer  152  also comprises threads on its inner surface that correspond to threads on the outer surface of the slider receiver  132  such that the retainer  152  is threaded onto the slider receiver  132  and the frame  102 . 
       FIG. 8B  shows a cross-sectional view of an assembled braking device  100 . The retainer  152  screws into the slider receiver  132  on the frame  102  such that the other components of the braking device  100  are secured. The flange on the proximate surface of the sliding collar  148  interfaces with the inward facing flange of the retainer  152 , and the ball  112  interfaces with the sliding collar&#39;s  148  aperture. One end of the spring  140  presses against a base of the slider receiver  132  or a spring cap, and the other end of the spring  140  presses against the locator disk  144 , which presses against the ball  112 . The ball presses against the sliding collar  148  which causes the flanges of the sliding collar  148  and the retainer  152  to interface. 
     Embodiments of the present invention may include adjustable components or features. For example, in  FIGS. 8A and 8B  the distance that the sliding collar  148  extends outward from the frame  102  may be adjusted. The flange on the proximate surface of the sliding collar  148  governs the maximum distance that the sliding collar  148  may extend outward. A user can alter the distance by altering the interface between the sliding collar&#39;s  148  flange and the inward facing flange of the retainer  152 . A user may insert an object between the flanges to move the sliding collar  148  further into the frame  102 . Objects such as washers, o-rings, or other similar objects may be utilized to adjust the distance that the sliding collar  148  extends outward from the frame  102 . 
     A more straightforward adjustment of the braking device  100  is the substitution of the spring  140  for another spring  140 . The replacement spring  140  may have different properties such as stiffness. Further, the scope of the present invention is not limited to springs  140 . In some embodiments air cushions, leaf springs, hydraulics, or magnetic repulsion may be used to providing a dampening effect between the ball  112  and the frame  102 . Further yet, embodiments of the present invention are not limited to the linear force equation of the spring  140 :
 
 F=k ( x   2   −x   1 )
 
where F is the force generated by the compression of the spring, k is the stiffness constant of the spring, x 2  is the final position of the spring, and x 1  is the initial position of the spring. Other embodiments may comprise features that exhibit non-linear responses to various inputs. In some embodiments, this may mean that the initial input results in little response, but after a threshold input the resulting response greatly increases, similar to an ice skater or snowboarder using an edge to turn.
 
     The embodiment depicted in  FIGS. 8A and 8B  comprise a retainer  152  selectively interconnected to the slider receiver  132 . In this embodiment, the selective interconnection is a threaded connection where a user screws the retainer  152  onto the slider receiver  132 . One skilled in the art will appreciate other means of selective interconnection. The retainer  152  allows a user to quickly disassemble the braking device  100  and change out worn parts or upgrade with improved parts. 
       FIGS. 9A-9C  show various views of the frame  102  and braking device  100 .  FIG. 9A  shows the spring cap  116 , the locator disk  144 , the slider  108 , and the ball  112  in an exploded view. Also shown in  FIG. 9A  are two ribs on the outer diameter of the slider  108 , one rib disposed toward the leading edge of the frame  102  and one rib disposed towards the trailing edge of the frame  102 . These ribs correspond to notches in the slider receivers in the frame  102  such that the sliders do not rotate when the user engages the braking device  100 . The top edge of the slider  108  has a flange that extends outward. This flange governs the extent to which a spring can press the ball  112  and the slider  108  outward from the frame  102 . When a user inserts the slider  108  through a base opening on top of the frame  102 , the slider  108  passes through the slider receiver, and the slider  108  extends outward from the frame  102 . However, the flange catches the inner surface of the slider receiver, and the slider  108  cannot extend all the way through the slider receiver. This allows the braking device  100  to function without a retainer as described elsewhere herein.  FIG. 9B  shows the embodiment in  FIG. 9A  where the components are assembled into a frame  102  and a braking device  100 .  FIG. 9C  shows an isometric view of a frame  102  and three braking devices  100  with the rib-notch configuration described above. 
     Although a generic ball  112  is used as an example of a friction-generating device in  FIGS. 9A-9C , the ball  112  may be configured to interact with a variety of surfaces and conditions. For example, when embodiments of the present invention are used on a sport court, the ball  112  may be a compliant and made from the same or similar material as the wheel or court, which includes, but is not limited to, polyurethane, hard rubber, copolymer plastic, aluminum, carbon fiber, and titanium. On less forgiving surfaces such as asphalt and concrete the ball  112  may be made from a stiffer material to prevent ball deformation. Further, the ball  112  may be dimpled, created by a bead-blasting technique, for example. Surface features that add texture to the ball  112  can extend its useful life within embodiments of the present invention. 
     Even further, other embodiments of the present invention do not utilize a ball  112  as a friction-generating device. Other embodiments utilize a bar that has a longitudinal axis disposed substantially parallel to the longitudinal axis of the slider receiver. Further embodiments may utilize different orientations of the bar or other friction-generating device including, but not limited to, disks, blades, wheels, rectangular prisms, and plates. 
     One skilled in the art will appreciate the ball  112 , or friction-generating device, is not the only component that may provide the braking force against a surface. Other components of the braking device  100  such as the slider  108  may contact the ground and generate braking friction. This may prove advantageous because a greater surface area contacts the ground and provides additional friction and braking force. There is also advantage in the multi-stage aspect of the slider  108  contacting the ground. As the ball  112  contacts the surface a certain amount of braking force exists, but as the slider  108  contacts the surface there is a jump in braking force. This may be akin to ice skates cutting into the ice with an edge of the skate&#39;s blade. Further embodiments of this concept are not limited to the slider  108 , and other embodiments may comprise several components that progressively contact the surface as a user engages the braking device  100 , much like a telescoping device. One skilled in the art will appreciate various combinations of components that contact the ground at different stages of braking device  100  engagement to provide a braking force response that may be linear, non-linear, or otherwise. 
       FIGS. 9A-9C  show three braking devices  100  disposed on each side of the frame  102 . Other embodiments of the present invention may have different combinations and configurations of braking devices  100 . A side of the frame  102  may have fewer or greater braking devices  100  than three or even no braking devices  100  at all. In an asymmetric configuration, one side of the frame  102  has one or more braking devices  100 , and the opposite side has no braking devices  100 . This configuration may be advantageous because it&#39;s more economical and simpler than other configurations, and the single braking device  100  may be sufficient for the user&#39;s purposes. 
     Similarly, the braking devices  100  themselves need not be identical. In one embodiment, the center braking device  100  could comprise a larger ball  112  or a ball  112  that extends further from the frame  102 . This configuration would allow the center braking device  100  to contact a surface first and provide an initial braking force. As the user continues to tilt the frame  102 , the other two braking devices  100  may contact the surface and provide additional braking force. One skilled in the art will appreciate various symmetrical and asymmetrical combinations of the braking devices  100  to achieve various advantages. 
       FIGS. 10A-10C  show various views of a frame  102  according to an embodiment of the present invention.  FIG. 10A  shows a front elevation view of the frame  102 . The frame  102  is generally comprised of a horizontal extension  177  and first and second vertical extensions  178 ,  179  that descend below the horizontal extension  177 . In this embodiment, the first and second vertical extensions  178 ,  179  are substantially parallel to each other and substantially perpendicular to the horizontal extension  177 . One skilled in the art will appreciate other configurations and orientations of extensions. The vertical extension thickness  180  is approximately 5 mm. In this embodiment, there is bilateral symmetry about a vertical plane through the longitudinal axis of the frame  102 , and thus both vertical extensions  178 ,  179  have the same thickness in this embodiment. There is also a gap between the two vertical extensions  178 ,  179  where wheels of an in-line skate may be disposed. This vertical extension gap  184  is approximately 24 mm. Also, the horizontal extension  177  from which the two vertical extensions  178 ,  179  descend has a horizontal extension thickness  188  of approximately 5 mm. 
     The embodiment in  FIGS. 10A-10C  has slider receivers disposed on either side of the frame  102 . These slider receivers are generally cylindrical in shape, but in this embodiment ribs run along opposite sides of the slider receivers to reinforce the slider receivers and provide a notch on the inner surface of the slider receivers. When viewed from  FIG. 10A , the receiver rib thickness  192  is approximately 9.63 mm. Further, the lower sides of the receiver ribs  192  blend into the vertical extensions  178 ,  179  at a radius. The receiver radius  200  in this embodiment is approximately 5 mm. In addition, the slider receivers are oriented at an angle from a vertical plane traveling through the longitudinal axis of the frame  102 . The receiver angle  196  in this embodiment is approximately 33.75 degrees. 
     Other embodiments of the present invention may include a system to adjust the receiver angle  196  to an angle other than 33.75 degrees. The braking devices  100  arrayed on either side could be compartmentalized and discrete from the frame  102 . Such a braking device system could be affixed to a longitudinal axis on either side of the frame  102  where the braking device system could be adjusted to alter the receiver angle  196 . In some embodiments the receiver angle  196  is between approximately 0 and 90 degrees. In preferred embodiments of the present invention, the receiver angle  196  is between approximately 15 and 50 degrees. In a most preferred embodiment, the receiver angle  196  is approximately 33.75 degrees. 
       FIG. 10B  shows a top plane view of the frame  102  in  FIG. 10A . From this perspective, there are base openings disposed over the slider receivers. These base openings provide a location to dispose spring caps from which springs may press against. Also, these base openings are where another device  100 , such as an in-line boot, may interconnect with the frame  102 . The base openings in this embodiment are generally ovoid with a rectangular section disposed at the center of the base openings. The base opening length  204  is the length of the rectangular portion measured along the longitudinal axis of the frame  102 . The base opening length  204  in this embodiment is approximately 45.35 mm. 
     The base opening first width  208  is the width of the rectangular potion measured in the lateral direction, and the base opening first width is approximately 25.45 mm in this embodiment of the invention. The transition between the rectangular portion of the base opening  114  and the ovoid portion of the base opening  114  is not necessarily abrupt. Rather, the transition may be radiused. The base opening radius  216  in this embodiment is approximately 1 mm. In addition, the base horizontal extension width  212  in this embodiment is approximately 84 mm. 
     As mentioned above, the embodiment of the present invention depicted in  FIGS. 10A-10C  exhibits bilateral symmetry, and thus the base openings  114  are laterally centered on the horizontal extension  177  shown in  FIG. 10B . The longitudinal location of each base opening  114  can be expressed in terms of distance from the leading edge of the horizontal extension  177  to the center of the base opening  114 . The first base opening distance  220  is approximately 81.5 mm, the second base opening distance  224  is approximately 161.5 mm, and the third base opening distance  228  is approximately 241.5 mm. The horizontal extension length  232  is approximately 323 mm. Therefore, in this embodiment, the frame  102  is also symmetric about a lateral plane that extends through the center of the middle base opening. One skilled in the art will appreciate braking device location other than the symmetric ones described above. For example, it may be advantageous to group braking devices towards the leading edge or the trailing edge of the frame  102 . 
       FIG. 10C  shows a side elevation view of the embodiments shown in  FIGS. 10A and 10B . From this perspective, the vertical extensions  178 ,  179  are not a rectangle. Rather, the vertical extensions  178 ,  179  taper inward from the leading edge (and the trailing edge) at a vertical extension angle  240 , which is approximately 110 degrees in this embodiment. As the tapering edge approaches the bottom edge of the vertical extensions  178 ,  179 , the tapering edge curves inward at a vertical extension radius  236  to provide a smooth transition. The vertical extension radius  236  is approximately 30 mm. Further, the vertical extension radius  236  is curved about a single point on the vertical extensions  178 ,  179 . The horizontal distance between this point and the leading edge of the frame  102  is the first radius length  244 , which is approximately 39.93 mm in this embodiment. Likewise, the horizontal distance between the point about which the trailing edge radius is curved and the leading edge is the second radius length  265 , which is approximately 283.07 mm in this embodiment of the present invention. 
     Also shown in  FIG. 10C  are the various wheel axle apertures where the axles from wheel assemblies may be disposed. Similar to the base openings above, the longitudinal position of the wheel axle apertures can be measured from the leading edge of the frame  102  to the center of the wheel axle apertures. The first wheel aperture length  248  is approximately 42.5 mm, the second wheel apertures length  252  is approximately 120.5 mm, the third wheel aperture length  256  is approximately 199.5 mm, and the fourth wheel aperture length  260  is approximately 280.5 mm. In addition, the width of the receiver from rib to rib is shown in  FIG. 10C . In this embodiment, the receiver width  268  is approximately 51.35 mm. 
       FIGS. 11A-11C  show alternative isometric and elevation views of the embodiment in  FIGS. 10A-10C .  FIG. 11A  shows an isometric view of the frame  102  and corresponding slider receivers.  FIG. 11B  shows a type of elevation view of the frame  102  that is aligned with the longitudinal axis of the slider receivers. In other words, the frame  102  is tilted at 33.75 degrees to look straight down the slider receivers. The slider receivers have two different diameters when viewed from this perspective. The first receiver diameter  272  is approximately 41.36 mm, and the second receiver diameter  276  is approximately 31.88 mm. The transition between the smaller diameter and the larger diameter of the second receiver diameter  276  may provide a surface upon which a spring may press against. Further, there are two notches in the second receiver diameter  276 . These notches are on opposite sides of the second receiver diameter  276  with one disposed towards the leading edge of the frame  102  and one disposed towards the trailing edge of the frame  102 . The notch height  280  is approximately 3.63 mm. The distance between the outermost edge of the notch and the center of the slider receiver is the first receiver radius  284 , which is approximately 8.68 mm. The distance between the outermost edge of the notch and the outermost edge of the receiver rib is the receiver rib width  288 , which is approximately 7.07 mm. 
       FIG. 11C  shows another perspective of the frame  102  from  FIGS. 11A and 11B , but this perspective is the opposite of that in  FIG. 11B . In other words, the perspective in  FIG. 11C  is a top plane view of the frame  102  that has been tipped at 33.75 degrees. From this vantage, one can see the third receiver diameter  292 , which in this embodiment is the same as the first receiver diameter  272  of 41.36 mm. 
     For exemplary purposes only, most embodiments of the present invention described herein have been directed toward in-line skates. However, the present invention should not be limited to only in-line skates. The present invention is applicable to any device that may benefit from present invention and the braking devices described herein. For example, embodiments of the present invention may be utilized on bicycles, ice skates, or motorcycles. 
     Similarly, most embodiments of the present invention described herein have been directed toward stand-alone in-line skates with braking devices already incorporated into the frame of the in-line skates. In other embodiments of the present invention, the braking device, or combination of braking devices, may be adapted for use on existing in-line skates that do not have slider receivers or other braking device components integrated into the frame. 
     The phrases “at least one”, “one or more”, and “and/or”, as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B, and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C,” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B, and C together. 
     Unless otherwise indicated, all numbers expressing quantities, dimensions, conditions, and so forth used in the specification, drawings, and claims are to be understood as being modified in all instances by the term “about” or “approximately.” 
     The term “a” or “an” entity, as used herein, refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. 
     The use of “including,” “comprising,” or “having,” and variations thereof, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Accordingly, the terms “including,” “comprising,” or “having” and variations thereof can be used interchangeably herein. 
     It shall be understood that the term “means” as used herein shall be given its broadest possible interpretation in accordance with 35 U.S.C., Section 112(f). Accordingly, a claim incorporating the term “means” shall cover all structures, materials, or acts set forth herein, and all of the equivalents thereof. Further, the structures, materials, or acts, and the equivalents thereof, shall include all those described in the summary of the invention, brief description of the drawings, detailed description, abstract, and claims themselves. 
     The foregoing description of the present invention has been presented for illustration and description purposes. However, the description is not intended to limit the invention to only the forms disclosed herein. In the foregoing Detailed Description for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention. 
     Consequently, variations and modifications commensurate with the above teachings and skill and knowledge of the relevant art are within the scope of the present invention. The embodiments described herein above are further intended to explain best modes of practicing the invention and to enable others skilled in the art to utilize the invention in such a manner, or include other embodiments with various modifications as required by the particular application(s) or use(s) of the present invention. Thus, it is intended that the claims be construed to include alternative embodiments to the extent permitted by the prior art.