Abstract:
This skateboard invention has novel swiveling caster wheels mounted on a cross carriage (axle) holding spaced apart swivel caster wheels in place on the undersurface of the board by fixed in place fastening brackets. Dual front and dual rear caster wheels—two in front and two in the rear—as well as a three caster wheeled skateboard is disclosed. Inwardly directed axle stubs (angled toward the center of the board, front and back) are employed with said stubs holding long front and long rear caster arms with wheel hubs supported by the long caster arms. A centering movement for the cross axles—whether front and/or rear—and each caster wheel is disclosed such that the cross axle and/or wheel returns itself to an initial straight line position.

Description:
This is a regular patent application that is being timely filed within the one year period allotted from a Provisional Application Entitled “Three Caster Skateboard” as filed on Nov. 12, 2010 having the same inventor as hereof and awarded Ser. No. 61/456,845. 
    
    
     FIELD OF INVENTION 
     This invention relates to the field of sports and the sport of skateboarding in particular. A new method and an improved apparatus are disclosed. This invention improves a known sport while providing a new method and structure that has many advantages over known prior art skateboards. The apparatus finds particular strength in regard to a self forwarding, narrow caster wheeled skateboard that “walks” and does not require the user to push off in order to get the board moving. Instead, the board invention “walks” itself forward in response to user weight. Such weight is amplified by shifts—in a move similar to a twisting dance step—from one side of the board to neutral and onto the opposite board side. Such weight shifts amplify the natural forward force on the board. 
     BACKGROUND OF THE INVENTION 
     A skateboard is a small piece of wood in the shape of a surfboard with predominantly four non-swivel wheels attached to it. A single person rides the skateboard, guiding and initiating movement by his feet. While some skateboards are useful as transportation over short distances, most skateboards are used to perform stunts. 
     Skateboards consist of three parts: the deck (the actual board), the truck (a component usually made of metal that holds the fixed wheels to the deck), and the wheels. The average skateboard deck is about 32 in (81.3 cm) long, 8 in (20.3 cm) wide, and is a little less than 0.5 in (1.3 cm) thick. The deck has a defined nose and tail end with a generally concave section in the middle. Skateboard wheels are usually made of polyurethane and range in width from about 1.3-1.5 in (3.3-3.8 cm). While nearly all skateboards have similar shapes and characteristics, their dimensions vary slightly based on use. There are skateboards built for speed, slalom, and freestyle. 
     Historical Background 
     Though there is unconfirmed evidence that a skateboard-like apparatus existed as early as 1904, the more commonly accepted predecessor to the skateboard was created in the 1930s. In Southern California, a skate-scooter was made out of fruit crates with wheels attached to the bottom. This evolved into an early skateboard that was made out of 2×4 ft. (61×121.9 cm) piece of wood and four fixed metal wheels taken from a scooter or from roller skates. This early version of the skateboard featured rigid axles and fixed wheels. 
     Recognizable skateboards were first manufactured in the late 1950s. These were still made of wood and a few were decorated with decals and artwork. Skateboards became especially popular among surfing enthusiasts, primarily in California. Surfers practiced on skateboards when the ocean was too rough, and they became known as “sidewalk surfers.” 
     There was a renewed interest in skateboards when wheels made of polyurethane were introduced. These early polyurethane wheels were composites of sand-like material that was formed into a flat and wide wheel with an adhesive binder under extreme pressure. With the advent of such polyurethane wheels, boards became easier to control and more stunts were possible. 
     Subsequently, skate parks were introduced. Skate parks were specially designed places that catered specifically to skateboarders. Popular interest in skateboarding increased due both to improvements in technical innovation and skateboarding videos which featured skateboarders performing extremely difficult and dangerous stunts using ramps, stairs, handrails and the like. New interest in the sport resulted. High-profile exposure like ESPN and MTV&#39;s X-Games and skateboard competition added increased interest in the sport. Televised events of “extreme sports” showed the best of many kinds of skateboarding. Skateboarding was regarded as the first extreme sport. 
     Skateboard technology has also continued to evolve. Skateboard manufacturers experimented with different thicknesses of veneers for the decks, but practically speaking, very little has changed in the actual manufacture components of skateboards until this invention. 
     Raw Materials 
     Most skateboard decks are made of glue and wood (usually maple), but some are made of composites, aluminum, nylon, Plexiglas, fiberglass, foam, and other artificial materials. Skateboard trucks are usually made of aluminum or other metal (steel, brass, or another alloy), though a few are made of nylon. These trucks, in all prior art skateboards, are fixedly mounted on a vertical post fastened or formed in the bottom of the board. 
     To assemble a skateboard, the maker also needs ball bearings (usually full precision and made of metal) and a sizable piece of grip tape. Grip tape comes in a sufficiently large piece—bigger than the deck—and looks like a piece of sandpaper. It is secured to the top of the deck, friction surface upward, to provide traction for the user&#39;s feet. 
     FEATURES OF THE INVENTION 
     Particular attention is directed to the chassis underneath the upper board surface. The improved chassis of this invention has an angled front and an angled rear axle stub to which are attached narrow caster type wheels with a rounded traction surface. Such caster wheels are further characterized as having a pair of support arms swivel mounting said wheels to mounting stubs supported by the underneath surface of the board and behind which the caster wheels themselves follow and swivel. 
     In the invention the mounting posts, or studs, are bracket mounted at central positions at the front and at the rear of the board proper. These studs are spaced apart and are mounted centrally along the longitudinal axis which runs the length of the board and are leaning inward so that they face each other. The angles which these studs make with the plane of board surface are selected between 20 degrees and 40 degrees for the rear casters and about 60 degrees for the front caster. 
     The mounting angles change for different performance characteristics. The steeper the angle, the more the wheels and the board leans. Simply stated, angles control the performance characteristics for the board. Accordingly, this orientation, together with other novel features described and depicted herein, provides for improved stability. The novel combinations as described herein are responsible for added versatility in movement and turning maneuvers that may readily be accomplished by this caster wheeled skateboard invention. 
     Several new features, neither shown nor suggested by prior art skateboards are presented by this invention. First, novel swiveling caster wheel embodiments—rather than fixed wheels—are employed. Second, a carriage cross (axle) holding two spaced apart swivel caster wheels is held in place to the undersurface of the board by fixed in place fastening brackets. Dual front and dual rear caster wheels may be employed. The board, however, does not turn as sharply with a total of four caster wheels—two in front and two in the rear—as compared to a three caster wheeled board. Third, inwardly directed axle stubs (angled toward the center of the board, front and back) are employed with said stubs holding long front and long rear caster arms with wheel hubs supported by the long caster arms. A unique combination of technical features allows for a sizable and novel turning and performance movements as provided by the invention. 
     A full 360 degree swivel movement is available in the front of the board for a three-caster wheel embodiment. Downward weight on such a caster wheeled board is translated to a forward force on the board simply in response to such downward weight or force. A distinguishing feature of a caster wheel skateboard is the necessity of a centering movement for the cross axles—whether front and/or rear—such that the cross axle returns to a straight line position. Extra maneuverability is achieved by caster wheels, and the return-to-center structure for the cross axle is a significant feature for a caster wheeled skate board. 
     Standard prior art boards with fixed wheels do not face this wheel and axle centering problem, nor do they achieve the flexibility and significant accomplishments of the invention. 
     Several embodiments of a caster wheel axle return-to-center position direction feature are presented herein. As described, each has as its basic structure, a version of spring loading in order to assure a self centering position for the caster axles and individually for all of the caster wheels. Additionally the extreme maneuverability of this skateboard invention has warranted, or required, a braking mechanism. A skateboard braking mechanism of this invention is readily activated by the user&#39;s heel. Other new and novel features will readily become apparent as the caster skateboard invention is described and claimed in more depth. 
     I am enclosing herein several drawing figures that assist in understanding and appreciating the description and the principles of my invention. Each Figure is numbered and each demonstrates new and unique features that are described in my written description. This patent application drawing is identified and discussed herein by appropriate Figures and is provided with number designations in order to further exemplify the novelty of the invention. 
    
    
     
       DESCRIPTION OF THE FIGURES OF THE DRAWING 
         FIG. 1  is a side perspective view looking down on my three caster-wheeled skateboard invention; 
         FIG. 2  depicts the underside of a development board and clearly shows a front caster, and a pair of rear casters together with an embodiment of a return-to-center position structure for the rear truck and axle configuration; 
         FIG. 3  depicts another underside view having a second return-to-center or return-to-neutral structure for the rear truck and axle configuration and discloses structural detail about the underside of the brake for the skate board of the invention; 
         FIG. 4  depicts a partial cutaway view of a dual mounting bracket fastened on the underside of the board with one mounting for the stud holding the rear axle and the other mounting for a return to center position embodiment of the invention. This  FIG. 4  also includes  FIG. 4A  which is an enlarged cross section of a portion of the mounting bracket, which enlarged cross section depicts figuratively a downward weight absorbing assembly for angled downward forces as initiated by rider weight shifts; 
         FIG. 5  includes  FIGS. 5A ,  5 B,  5 C, and  5 D and exemplifies a “walking” movement of my skateboard invention; 
         FIG. 6  includes  FIGS. 6A and 6B  which together depict another return-to-center position embodiment for my invention; and 
         FIG. 7  supplies some additional operational views helpful in understanding the braking system of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     I will describe the apparatus and process involved by reference first to  FIG. 1 .  FIG. 1 , a side perspective view, depicts board  50  having a total of three caster wheels  60 ,  80  and  90 . Other inventive embodiments may have a total of four caster wheels with a pair of long caster wheels both in front and in the rear. Each caster wheel is characterized by having a swivel mounting on an angled stub fastened into or formed in the underside of board  50 . Front stub  55  is angled slightly to the rear while rear stub  70  is angled toward the front of the board. 
       FIG. 2 , a development model without a brake assembly  300  of  FIG. 1 , supplies more operational detail. In  FIG. 2 , front caster  60 , housed in cantilever yoke  62 , is swiveled for full rotation about the angled stub  55 . The flexibility and stunt-performing capability of this board  50  is perhaps mostly attributed to the rear dual caster truck comprising stud  70  and cross axle  71  that carries caster wheels  80  and  90 . Cross axle  71  is swivel mounted on a central stub  70  that is angled toward the front of the board  50 . 
     In accordance with the principles of my invention, there is in this embodiment a centering spring  20 ,  FIG. 2 , which is turnbuckle connected at one end beyond the center of the board at fastener  25 . The other end of centering spring  20  is connected by Y brace  32 , which brace is rigidly linked to the cross arm or axle  71 . The actual swivel movement of the rear truck and caster wheels may be limited in part by the wheels either contacting the side of the board when turned too far, and/or by the centering spring assembly  20  which prevents overly large swings. With too large swings, the board will simply tip over. As it is, the board  50  turns very sharply and is capable of executing extreme stunts including 360 degree circles by the rider. 
     Returning briefly to  FIG. 1 , the distance between the mounting stub  55  and the axis for caster wheel  60  is about five to six inches. Weight shifts on the board cause a twisting (leverage) motion on the wheel&#39;s axle (and on the caster wheels themselves) which fixed wheel skateboards just do not exhibit. Casters for this invention may be referred to as “long” casters because the forks or yoke  62  are long in distance between the mounting point and the wheel axle itself. In shorthand technical terms, these long casters travel “higher uphill or higher downhill” as explained in more detail by reference to  FIG. 5  hereafter. And, that “uphill” and/or “downhill” movement is what makes this caster wheeled skateboard invention develop a move forward force on its own. The higher up hill each caster wheel travels, the more forward force the board provides on its own momentum as the caster wheels return to center position or direction. 
     The upper surface of board  50 ,  FIG. 1 , receives a user in the normal fashion facing generally sideways, but looking forward, with the user&#39;s feet spread apart slightly. As the user shifts his/her weight, the board will, on its own, start to “walk” in response to such user weight shifts. This “walking” for a three caster board, involves first one rear caster moving forward, followed by the other rear caster moving forward. Both movements are in response to weight shifts by the rider using the board. In other words, one does not have to “shove” or “push off” in order to get the board moving. Instead, it will start forward on its own (“walks”) as the rider shifts his/her weight in a twist type movement. 
     This novel “walking” movement by the board is first disclosed and taught by the principles of this invention. This “walking” feature is depicted best in  FIG. 5  which includes some side-by-side views, depicted at the bottom, middle and partial top views of  FIG. 5 . Taken as a whole,  FIG. 5  shows the manner in which the board tilts and moves in response to weight shifts by the user. 
     Look first at the bottom side by side view  FIG. 5A , of  FIG. 5 . Please understand that the bottom end view,  FIG. 5A , of the board  50  is shown in a balanced, or neutral, weight situation. The caster wheels in this condition are in a straight or neutral position. The middle and top end views,  FIG. 5A  and  FIG. 5B , of board  50  show how the board tilts when weight, applied on opposite board sides, causes board  50  to shift away from a neutral position and begin its forward motion. 
     At  FIG. 5A  is a situation where the user&#39;s weight is evenly, or neutrally, balanced. This is shown by the end view whereby board  50  is shown as level. Accordingly, the straight forward movement for the board  50  would be along the direction shown by arrow  250 . This is a balanced or neutral condition for the board 
     In the middle of  FIG. 5 , at  FIG. 5B , the user&#39;s weight has shifted heavily to the right hand or inside side edge, and the board  50  has tilted down on the right as shown (Looking, of course, at the rear end of board  50 ). Note then, that the rear caster wheel  90  moves forward on the board&#39;s tilted side in response to that weight shift. Accordingly, the rear caster wheel  90  moves forward, and relatively speaking, the left hand caster wheel  80 , in essence, has dropped back. Board  50  thus swings to the inside right as would be expected due to the extra weight on that side. 
     Please note that the front caster wheel  60  swivels or pivots in a direction that is opposite to the pivoting direction of the rear caster wheels on axle  71 . This difference in pivot direction makes for a smooth transition between turns, and sets the general direction of the board&#39;s movement. Thus, contra steering by opposite pivot directions of front and rear caster wheels has a valuable result not heretofore experienced in this art. 
     Summarizing then, the rider&#39;s weight on one edge of board  50 , causes axle  71  to swivel on its own in response to that extra weight on that side of the board. Indeed, both caster wheels  80  and  90  have climbed “up” hill as shown the wheel outlines on arc  130  in  FIG. 5D . Then, as the user shifts his weight toward the other side of the board, the rear axle swivels the other direction on arc  130  and the caster wheels come “down” hill. This “up” hill followed by a “down” hill movement is what causes a force which moves board  50  forward in a direction along arrow  250 . 
     Step by step, the board “walks” on its own in response to rider weight shifts. Each weight shift thus results in a new “up hill” movement followed by a “down hill” movement that creates additional forward force for board  50 . The caster wheels and axles of this invention achieve this totally new result. Results not known before or contemplated by the fixed wheel prior art skateboards are achieved by the invention. Other new and improved features will readily be appreciated by the reader as the invention is more fully described herein. 
     Fastener  25 ,  FIG. 2 , anchors centering spring assembly  20  in place. An exterior spring-turnbuckle assembly  20  may tend toward damage due to extreme stunts and maneuvers. The spring assembly  20  is safer if concealed. What is essential, however, is that the same return-to-center position function and associated structure takes place for board  50 . Other centering forms of the invention, as disclosed herein, may be employed such as those self contained in the housing  42  of  FIGS. 4 and 6 . 
     Bracket  42 ,  FIG. 4 , is a dual mounting structure for two distinct shafts. One shaft is the mounting stud  70  that is on an axis  72  that leans toward the center of the board  50 . Stud  70  is actually an anchoring stud or king pin machined in, or otherwise formed in the yoke-shaped portion of cross axle  71 . This protrusion of axle  71  is seated in an appropriate receiving opening aligned on the mounting axis  72  formed in a shoulder on bracket  42 . 
     Note that both of the mountings in bracket  42  are on axes that intersect one another at a right angle, with one axis leaning forward (mounting stud axis  72 ) and one axis (return shaft axis  49 ) leaning rearward. Rear axle  71  swivels right or left about a central hole therein which is secured by a nut  48 ,  FIG. 3 , riding on the top of axle  71 . Hole  48  aligns with and is seated over the threaded shaft  49  of the return to center system which is on axis  49 ,  FIG. 4 . 
     Rubber bushing  40  will be compressed equally for a neutral position initially and that bushing will further compress on one side or the other as weight shifts by the rider take place. Bushing  40 , however, always tries to urge axle  71  back to a neutral or balanced condition. 
     Caster wheels normally have a 360 degree turning ability. The caster wheels of the invention don&#39;t turn that far because I have provided a caster wheel limiting and centering function that does not allow the wheels to swing to that extreme. Indeed, all three casters have a centering function mounted within the swivel housings  10 ,  30  and  35  of  FIG. 3 . Such structure restricts the turning ability of these casters 60, 80 and 90 to about 90 degrees. 
     Swivel bearings  10 ,  30  and  35 ,  FIG. 3 , are employed for each caster wheel  60 ,  80  and  90 . Note in  FIG. 3  that the caster wheels are thin and rounded for smooth turning and stunts about the swivel bearings provided for all caster wheels. These swivel bearings allow the caster(s) to smoothly swivel within fixed limits. Each bearing is a group of three bearings stacked one above the other on a common central axis as is described in greater detail hereinafter. Briefly, however, the upper and lower bearings of each bearing group are standard smaller-sized ball bearings. The middle position bearing of each group is actually a return-to-neutral or center position bearing. 
     The bearings for board  50 , such as bearing groups  10 ,  30  and  35  each have a return to center structure located within them. Furthermore, such bearings also restrict the amount of swing for the wheels  60 ,  80  and  90 . Clearly wheels  60 ,  80  and  90  swing both right and to the left, but the caster wheel motion for the invention is more complex than that. 
     Each caster wheel travels in an arc shape as symbolically shown by the upward curved arc  130  presented in the drawing of  FIG. 5D  of  FIG. 5 . For straight travel, the caster wheels  60 ,  80  or  90  are at the valley of its own arc. Weight shifts moves the wheels away from that valley or center position. Thus, pivoting of weight by the rider, either right or left, results in the wheels actually travelling up hill as it swings along arc  130 ,  FIG. 5D , from its neutral position. When the board is in use and the wheels are in contact with the skate surface, such wheel movement translates to a forward force for the board itself. 
     A downward force applied to the board provides enough rotating motion to the caster wheels that the board  50  will be propelled in a forward direction. Understand that this forward motion to board  50  is done on its own in response to a downward force (rider&#39;s weight) on the board. Twisting weight shifts by the rider further amplify this forward movement and the board is off and rolling without any necessity for the rider to push off. 
     A caster wheeled skateboard requires a return to center structure for reasons of safety and practicality. Another embodiment of a return-to-center device is depicted in  FIG. 6 . This embodiment, which may be embedded within bracket  42  of  FIG. 4  (or bracket  55  of  FIG. 1 ) acts as a return to neutral structure. In either case, however, such structure and function is associated with mounting stub  70  for rear axle  71 ,  FIG. 4 . This return to center employs a principle of operation which is basically the same as that described for  FIG. 2 . While  FIG. 2  relies upon an externally visible spring  20 , the centering of  FIG. 4  is contained out of sight in a bearing group  160  to be described in connection with  FIG. 6 . 
     Each caster wheel is outfitted with a bearing group  160  for a smooth transition between maneuvers. Every caster must pivot and return to neutral after the transition. Additionally, each caster wheel must bear the weight of the rider and yet smoothly turn as required for stunts and enjoyment of use.  FIG. 6  includes  FIGS. 6A and 6B  which respectively are a side and a top view of a bearing group  160 . Such a group would, for example, constitute one bearing each for both the front and rear caster wheels  60 ,  80  and  90  of  FIG. 1 . Assume, for discussion purposes, that the structure shown in  FIG. 6  is for a front caster wheel  60 ,  FIG. 3 . 
       FIG. 6  depicts a cutaway top and side view with the top view looking into an individual return to center bearing  175  of the bearing group  160 . Middle position bearing  175  is seated in an outer housing  140 , which housing  140  forms part of the spoke (“yoke”) arms for caster wheel  60 .  FIG. 6  shows a similar portion of this outer housing  140  which also show an Allen screw  181 , which screw connects the outer housing  140  to an inner divider stub  186 . 
     As a caster wheel, such as wheel  60 ,  FIG. 1 , pivots, the outer housing  140  rotates with it. Reference to  FIG. 6A  discloses that the inner stub  186  receives an Allen screw  181  through housing  140 . Thus, components  186  and housing  140  are rigidly fastened together, and both rotate as a single unit. 
     Mounting stud  55  is shaped with a flat surface  55 A such that divider  56  is fixed in position within outer housing  140 ; and housing  140  rotates about a divider bridge  56  and stud  55 . Divider  56 , as shaped, becomes in essence, part of stud  55 . As best depicted in  FIG. 6A , some—or all—of the race space normally occupied by ball bearings has been replaced instead by strong springs  190 ,  191  and a limited number of ball bearings positioned at the extreme ends of the springs. Clearly if the springs  190 ,  191  occupy all of the race space no ball bearings are present at all. I have found that each option provides satisfactory results. Regardless of the set up, however, each such spring is nestled within each half of the race. These springs  190 ,  191  are in a balanced state when the housing  140  and its attached caster wheel  60  are in a center, or neutral, position. That neutral position defines a continuing straight forward motion. 
     Springs  190  and  191 —when either spring is compressed—act as a centering spring in order to move the housing  140 , and therefore the caster wheel, such as  60 ,  FIG. 1 , back to a standard center position. The operation is as follows. Swivel movement, left or right,  FIG. 6 , creates a compression build up in one spring (say spring  190 ) and an expansion or lengthening of the other spring,  191 . 
     For example, a clockwise rotation of caster wheel  60  results in a corresponding clockwise rotation of housing  140  as shown by arrow  188 ,  FIG. 6A . Such a rotation will compress spring  190  and lengthen spring  191 . Centering spring  190  then resumes its normal condition and will move the housing  140  back to its initial position. Thus, concurrently with the user&#39;s weight shift back to a balanced, or neutral direction, for board  50 , spring  190  expands back to an initial condition. Board  50  is thus returned to its balanced straight ahead configuration. 
     Referring again to  FIGS. 3 and 4 , a dual mounting bracket  42  is depicted. Two separate mounting axes are defined by the bracket  42 . One axis  72  is along the stud  70  which holds axle  71  in place. The other axis  49  is along a shaft  48 ,  FIG. 3 , that houses a single rubber bushing  40  between the underside of axle  71  and the shaft seat in an angled shelf  38  formed or otherwise affixed in bracket  42 ,  FIG. 4 . 
     These two axes are at right angles to each other and operate together with the structure as shown which serves to bring axle  71  back to center. Thus bracket  42  is both a supporting and a return-to-center structure for rear axle  71 . Although not shown, a pair of rubber bushings, such as  40 , may be employed on both sides of the axle hanger  71  in order to absorb the twisting motion caused by a rider. If, however, the force caused by the rider is too great, twisting in the board may cause a pair of rubber bushings to separate and wear excessively. 
     I found that by replacing an upper rubber bushing with a well known Ball Swivel Joint (not shown) located just beneath nut  48 ,  FIG. 3 , the axle  71  is both advantageously mounted and the board performs well. Such a technique also prevents the rubber bushing  40  from excessive wear. My desired rotating motion of axle  71 , however, is still available and board  50  exhibits the walking movement described above for  FIG. 5 . 
     Turning to the enlargement of  FIG. 4A , as the user shifts his/her weight on the board, the twist by weight shift is actually directed at an angle downward. It is not, however, straight down. A ball and socket type mounting  185  in bracket  42  takes advantage of this angled twist by employing a pivot, or cup, bushing shown in cross section in  FIG. 4A . Bushing  185  forms the circular socket element in a ball and socket type mounting assembly as shown figuratively in  FIG. 4A . The lowest end  70 A of mounting stud  70  is rounded on the mounting end. That rounded end  70 A sits in a mating rubber cup or pivot bushing  185  as shown in the enlargement of  FIG. 4A . Together they absorb the angled downward thrust of the rider&#39;s weight shifts. 
     Protruding outwardly from the center of the cross axle is a pivot stem  70  with a rounded pivot ball  185  shown partially in black cross hatching surrounding stub  70 . This rounded ball is seated in a rubber lined cup  185  secured within the fastening bracket  42 . The rubber lined cup  185  acts as a side thrust absorbing structure. Pivot stem  70 A and its rounded ball and socket type junction  185  serve an important role in responding to the twisted force resulting from a weigh shift by the rider. This pivot ball-and-cup  70 ,  185  provides relative movement for the axle  71  as a rider weight shift takes place. To the hand touch, the axle  71  feels rigid, but when the rider weight shift on the board  50  takes place, a great deal of force is transmitted to the axle  71  and the cone bushing  185 . 
     In  FIG. 3 , a rearward leaning centering stud  49  leans toward the back of the board and helps support the cross axle  71  in proper position for holding a pair of rear caster wheels  80  and  90 . This cross axle  71 , for centering purposes, is hung on a single cone bushing  40  made of hard rubber, or other firm but yieldable substance. Top nut  48 , when sufficiently tightened during assembly, evenly compresses the rubber bushing  40  beneath the cross axle  71  and holds axle  71  firmly in place. 
     Please note cone bushing  40 ,  FIG. 4 , which normally is evenly balanced at an initial centered position ie. a position that is without any imbalance in weight on board  50 . When a rider shifts his/her weight, however, one side of the cone bushing  40  is compressed and the other side simply follows (expands) along. The structure thus seeks to return-to center as described before. The centering axle hanger along axis  49  is forced back toward the normal balanced condition. Weight on the other side of board  50  does just the opposite to that described. In any event, the rubber cone bushing  40  tends to restore the axle  71  back to it original centered and balanced condition. 
     An added technical feature is the braking system  300  of this caster wheeled invention. A rear end section  310 ,  FIG. 1 , of the board  50  is separated from the rest of the board but yet is easily depressible by the user&#39;s weight. Brake actuation requires a downward force resulting from pressure, say by a user&#39;s heel. This tail section  310  of board  50  has affixed thereto a braking block  320 , FIGS.  1 , 3 ,  7  which block  320  is spring loaded to normally be held in an upright position at an angle of about 45 degrees above the board&#39;s upper plane or deck as shown best perhaps in  FIG. 1 . When pushed downward, say by the rider&#39;s heel, the braking surface  310  is depressed through linkage  340 ,  FIG. 7 , and becomes essentially level with the plane of board  50 . This braking system  300  still retains an overall streamlined appearance for the board while adding a valuable new and improved function and structure. 
     This braking block  320  is both hinged and spring loaded as depicted in  FIG. 3 . A double acting spring  330 ,  FIG. 3 , presses spring ends against both the braking tail section  310  and the rear end of primary board  50 . Spring  330  is normally biased upward at a selected upward angle amount (say 20 to 30 degrees as shown in  FIG. 1 ) for the braking block  320 . That upward bias for spring  330  is overcome by the user&#39;s application of the brake assembly  300 . Connecting linkages  340 ,  FIG. 7 , when pressed downward, forces the drag plug of block  320  into frictional contact with the surface  350  upon which the board  50  is operating. The frictional drag on block  320  against surface  350  stops board  50  safely and adds a valuable feature to my caster wheeled skateboard invention. 
     An added benefit of the drag plug  320  is that, when applied properly by the rider a momentary “brake” movement can also develop additional flexibility and maneuver-ability for this caster skateboard. For example, a momentary drag or “pop” brake force of plug  320  to surface  350 ,  FIG. 7 , allows the rider to perform additional extreme stunts. Braking system  300  thus provided increased safety and novel maneuverability while presenting a safe and efficient braking system for the board. 
     The invention provides many non obvious features and advantages over the prior art described above. Other novel features and advantages of this invention will readily become apparent in accordance with a brief summary of my inventive claims as set forth below.