Abstract:
The present invention relates to a novel skateboard truck. More particularly, the present invention pertains to skateboard truck with two independently adjustable pivot points that achieve a unique variable turning motion without affecting the skateboard&#39;s stability. Additionally, the skateboard truck includes an offset axle that swings towards the direction of the turn, thus shifting the wheels away from the side of the skateboard, eliminating wheel bite, and increasing stability.

Description:
RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Patent Application 61/939,058 filed on Feb. 12, 2014, entitled “Skateboard Truck with Adjustable Pivot Point”, the entirety of which is incorporated herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an improved skateboard and skateboard truck. More particularly, the present invention pertains to skateboard truck with two independent pivot points, one fixed pivot point and one adjustable pivot point, which provide a variable turning capability without affecting the skateboard&#39;s stability. 
         [0004]    2. Description of the Related Art 
         [0005]    Conventional skateboards include an elongated board (i.e., deck) with two steering mechanisms (i.e., trucks) that are attached to the underside of the deck. A steering mechanism or truck usually consists of a base plate, bushings, a hangar or axle, and wheels. The base plates are attached to the underside of the board and have a king pin bolt and a pivot cup. The hangar has an extended tip which mates with the pivot cup of the base plate and creates the pivot point. The hangar also has a circular opening which is mounted on the king pin along with a top and bottom bushing. The bushings and hangar circular opening are held onto the king pin bolt by a lock nut which is screwed onto the open end of king pin bolt. The strength of the bushings and the level the lock nut is tightened determine the range the hangar can move or flex. The hangar also has an axle running through the long part of the hangar. The wheels are attached to the axles and held on to the axles by lock nuts. Standard skateboards have two trucks mounted or attached on the underside and at the front and back of the deck. The axis of each truck or axle is typically attached perpendicular to the longitudinal axis of the deck. 
         [0006]    In order to steer the skateboard in a certain direction, the rider shifts their weight laterally across the longitudinal axis of the board causing the hangar to flex within the bushings and pivot cup mechanism to change the orientation of the truck axle with respect to the longitudinal axis of skateboard deck. The truck also serves as a suspension system that provides stability while the rider turns the skateboard. However, by stabilizing the board by tightening the king pin lock nut or by using harder bushings, the skateboard sacrifices its turning ability. 
         [0007]    Skateboards and skateboard trucks have been made the same way for many years. However, what is needed is a way to create flexible turning on skateboards while maintaining stability. 
       SUMMARY OF THE INVENTION 
       [0008]    This summary is provided to introduce concepts in a simplified form that are further described in the detailed description of the invention. This summary is not intended to identify key or essential inventive concepts of the claimed subject. 
         [0009]    The present invention overcomes the limitations of known skateboard trucks by providing a skateboard truck with two independently operating pivot points that achieve a variable turning motion without affecting the skateboard&#39;s stability. Specifically, the present invention provides a truck with a variable turning radius which may be adjusted or modified by changing the horizontal and vertical distance between the first pivot point of the axle assembly and the adjustable secondary pivot point. By including an adjustable secondary pivot point to the truck, the skateboard is able to make tighter turns with less tilt from the rider. This is accomplished by adjusting the amount of turning angle relative to the degree of the board. Stated alternatively, if the skateboard was held at a constant angle of tilt, one could alter the turning radius of the skateboard by moving the adjustable secondary pivot point. By adjusting the second pivot point, the geometry of the truck has changed thereby changing the turning ratio or angle of turn of the skateboard even though the skateboard angle of tilt was held constant. 
         [0010]    Adjusting the turning ratio is completely independent from the adjustment for board stability. Board stability in the present invention is achieved by rubber pads which are located on either side of the first pivot point, as well as a thin adjustable urethane pad positioned between the base plate and the bottom surface of the first pivot hub. By tightening the screws and driving the pad further into the decreasing space under the first pivot hub, stability is increased. The dual pivot point adjustment options of the present invention give users or skateboarders the ability to completely customize the ride of the skateboard to his or her preference. 
         [0011]    The present invention also includes a unique offset axle. The offset of the axle from the pivot point swings or moves the axle towards the direction of the turn, thus shifting the wheels away from the side of the skateboard and eliminating or reducing wheel bite. The offset axle also provides additional stability when steering the skateboard by shifting the center of gravity towards the direction of the turn. This center of gravity shift is achieved by moving the entire axle toward the turn. As the rider shifts his weight laterally across the board, the rider&#39;s center of gravity also moves in the direction of the turn, thus keeping the center of gravity of the truck consistently under the rider giving him much more stability during a turn. 
         [0012]    These and other objects, features, and/or advantages may accrue from various aspects of embodiments of the present invention, as described in more detail below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The foregoing summary, as well as the following detailed description of the invention, is better understood when read in conjunction with the appended drawing. For the purpose of illustrating the invention, exemplary constructions of the invention are shown in the drawings. However, the invention is not limited to the specific methods and instrumentalities disclosed herein. 
           [0014]      FIG. 1  illustrates a perspective top view of the main embodiment of the present invention. 
           [0015]      FIG. 2  illustrates an exploded view of the main embodiment of the present invention. 
           [0016]      FIG. 3  illustrates a cross-sectional view of the present invention&#39;s first pivot hub. 
           [0017]      FIG. 4  illustrates a cross-sectional view of the present invention&#39;s first pivot hub with the side stabilizing pads removed. 
           [0018]      FIG. 5  illustrates a perspective view of the main embodiment of the present invention with the adjustable second pivot assembly eyelet is positioned close to the first pivot assembly. 
           [0019]      FIG. 6  illustrates an alternative perspective view of the main embodiment of the present invention where the adjustable second pivot assembly eyelet is fully extended. 
           [0020]      FIGS. 7A-7F  illustrates the movement of the truck from the non-flexed position to a heavily flexed position. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0021]    With reference to the figures where like elements have been given like numerical designations to facilitate the reader&#39;s understanding of the present invention, the preferred embodiments of the present invention are set forth below. The enclosed figures and drawings are merely illustrative of one or more of the preferred embodiments and, as such, represent one or more ways of configuring the present invention. Although specific components, materials, configurations and uses are illustrated, it should be understood that a number of variations to the components and to the configuration of those components described herein and in the accompanying figures can be made without changing the scope and function of the invention set forth herein. For instance, although the figures and description provided herein show certain configurations for the skateboard truck assembly of the present invention, a skateboard utilizing such truck assembly and wheels mounted to the truck assembly, those who are skilled in the art will readily understand that this is merely for purposes of simplifying the present disclosure and that the present invention is not so limited. 
         [0022]    The preferred embodiment of the present invention is illustrated in  FIGS. 1-7 . As depicted in  FIGS. 1-6 , the truck  100  is comprised of a base plate  101 , a hanger  103 , a first pivot assembly, and a second pivot assembly. Attached to the hanger  103  are one or more axles  109 . The axels  109  or axel may be offset. One or more wheels  139  are connected to the axels  109  and are secured with a lock nut  110 . On the pivot end of the hangar, opposite from the axels  109 , is a first pivot opening  112 . Attached to the pivot end of the hangar  103  is a steering shaft  111 . The steering shaft  111  includes an attachment flange  113  which is mechanically fastened to the hanger  103  in a way that allows the steering shaft  111  to move along one axis relative to the hangar  103 . In the exemplary embodiment pictured, the attachment flange  113  is mechanically attached to the hanger  103  using threaded screws. 
         [0023]    The hanger  103  is connected to the first pivot assembly through the opening  112 . The first pivot assembly includes the base plate  101 , the first pivot hub  115 , the first pivot shaft  118 , the stability pads  141 , the wedge pad  143 , and the bearing assembly. The bearing assembly is comprised of several parts including washers  132 ,  133 , tapered roller bearings  130 ,  131 , roller bearing cups  128 ,  129  and a lock nut  135 . During assembly, the first pivot shaft  118  is inserted into an opening in the elevated sidewall  124 , then into a first bearing  125 , into an axial opening in the first pivot hub  115 , then into a second bearing  125  and terminating at a second elevated wall  124 . This places the first pivot hub into the cavity  126 . The first pivot hub  115  has a hub shaft  127  which is inserted through the washer  132 , roller bearing  130 , roller bearing cup  128 , the hanger opening  112 , roller bearing cup  129 , roller bearing  131 , washer  133  and finally through a lock nut  135 . The first pivot assembly secures the hanger  103  to the base plate  101  which is secured to the skateboard. The first bearing assembly allows the pivot hub  115  and shaft  127  (axis A in  FIG. 1 ) to rotate relative to the first pivot point created by the first pivot assembly. The degree of rotation of the shaft (a in  FIG. 1 ) is plus or minus 50° degrees relative to the non-flexed position. 
         [0024]    The base plate  101  has one or more screw slots  121  to receive screws that secure the truck  100  to the skateboard deck. The base plate  101  includes a housing  123  that includes a plurality of elevated sidewalls  124  forming a cavity  126  for retaining the first pivot hub  115 , the stability pads  141  (see  FIG. 3 ), and the wedge pad  143  ( FIG. 4 ). One or more of the elevated sidewalls  124  include circular openings for receiving the first pivot shaft  118 , and any screws  145 . The shaft  127  and first pivot hub  115  may be formed as one piece or fastened together by threaded mating party, welding, or similar means. 
         [0025]    As described above, the first pivot shaft  118  is inserted into the circular openings in the walls  124  and into the first pivot hub  115  to secure the first pivot hub  115  to the base plate  101 . In an exemplary embodiment, the base plate  101  is configured to hold the first pivot hub  115  at an angle relative to the skateboard deck. In the exemplary embodiment, the angle would be at, close to, or approximately twelve degrees. However, the angle could be lower or higher than twelve degrees. 
         [0026]    The truck  100  also includes a second pivot point through a second pivot assembly. The second pivot assembly includes a pivot pin  137 , a steering shaft  111 , and an eyeball bearing  138 . The base plate  101  contains a secondary pivot point adjustment slot  119 . This secondary pivot point adjustment slot  119  allows for the attachment of the secondary pivot pin  137  to the base plate  101 . This secondary pivot pin  137  can be adjusted horizontally along the adjustment slot  119  to modify the distance between the secondary pivot assembly and the first pivot assembly. The base plate  101  also contains a recess so that nut securing the secondary pivot pin  137  can sit flush with the base plate  101 . The secondary pivot pin  137  includes an eyelet  117  that can be raised or lowered along the pivot pin  137  shaft to further modify the variable turning radius of the steering shaft  111 . The steering shaft  111  is threaded through the eyeball bearing  138  and into the secondary pivot point eyelet  117  of the pivot pin  137 . The steering shaft  111  has an attachment flange  113  which is attached to the hanger  103  in a hinged configuration. 
         [0027]    As shown in  FIGS. 3-4 , the preferred embodiment of the present invention also includes side stabilizing pads  141  and an adjustable stabilizing wedge pad  143 . In the preferred embodiment of the present invention, the side stabilizing pads  141  are made out of rubber and the adjustable wedge pad  143  is made out of urethane. Alternative embodiments may utilize other materials such as hard urethane (100% urethane), soft or foam like urethane, or other suitable material. The design may also incorporate springs or other mechanical tension configurations. 
         [0028]    As shown in  FIG. 3 , two side rubber stabilizing pads  141  (one on either side of the shaft  127 ) are positioned to push against the top lip  116  of the first pivot hub  115 . As shown in  FIG. 4 , a wedge pad  143  resides or is placed under the pivot hub  115 . The wedge pad  143  is ideally a urethane stabilizing pad located between the base plate  101  and the bottom of the first pivot hub  115 . One or more screws  145  are threaded through the base plate wall to push or pull the wedge pad  143  within the cavity  126 . The wedge pad  143  has a wedge shape which when pushed further into the cavity  126  reduces the space the pivot hub  115  has to move. Further, the pivot hub  115  has to directly contend with the resistance of the wedge pad  143 . By tightening or lessening the screw  145 , the wedge pad  143  is pushed into the decreasing space under the first pivot hub  115  to tighten the pad and further increase the truck&#39;s stability. In other words, when the screw  145  is tightened, bias pressure is being added onto the pad  143  resulting in less space for the first pivot hub  115  to flex. 
         [0029]      FIGS. 5 and 6  illustrate the adjustable secondary pivot assembly. As previously described, the secondary pivot assembly includes a pivot pin  137 , a steering shaft  111 , and an eyeball bearing  138 . The pivot pin  137  is mechanically fastened to the base plate  101  by one or more threaded fasteners or nuts. The pivot pin  137  may be moved along the slot  119  to adjust the pivot point of the second pivot assembly. The closer the pivot pin  137  is (along the slot  119 ) to the first pivot assembly the truck  100  and board achieves a tighter deck turning radius allowing the skateboard rider to quickly turn the direction of the deck. As the pivot pin  137  is moved away from the first pivot assembly along the horizontal secondary pivot point adjustment slot  119 , the variable turning radius would provide a slower and wider turn. 
         [0030]    The pivot pin  137  has a threaded eyelet  117  which can rotate along the threaded shaft connected to the base plate  101  to increase or decrease the height of the eyelet  117  relative to the base plate  101 . The height adjustment also helps to increase or decrease the rotation of the hanger  103  with tighter turning ratios coming when the eyelet  117  is at its near its maximum height. The steering shaft  111  is inserted into an eyeball socket or bearing  138  and into the eyelet opening  117 . The steering shaft  111  rotates about the pivot point created by the pivot pin  137  along the B axis. The rotation (β) of the steering pin  111  relative to the pivot pin  137  is plus or minus 40° degrees from neutral for a total of an 80° degree rotational movement. This rotation (β) is important for movement of the hanger  103  and axels  109  during turns. 
         [0031]    The ability of the first pivot assembly to rotate plus or minus 50° degrees and the second pivot assembly to rotate plus or minus 40° degrees enables the hanger  103  and axels  109  to move significantly relative to the longitudinal axis of the board. For comparison, a standard skateboard truck under flex from a rider might cause the truck axel axis (generally perpendicular to the longitudinal axis of the board) to rotate plus or minus 20° degrees from the normal non-flexed axel axis. By comparison, the dual pivot assembly of the present invention allows the axel axis to rotate plus or minus 50° degrees from the non-flexed axel axis position. The increased axel rotation enables greater turning options. 
         [0032]    However, another important aspect of the present invention is that during these extended rotational turns, the truck  100  design shifts the axel midpoint toward the direction of the turn or weight of the user. This axel midpoint shift increases the stability of the board during turns. As seen in  FIGS. 7A-7F , the axel midpoint  99  shifts relative to the starting position or un-flexed position. The skateboards in  FIGS. 7A-7B  depict a truck  100  of the present invention on the front of the deck only. However, the truck  100  of the present invention could be used as the front and back truck.  FIGS. 7A ,  7 C, and  7 E illustrated the underside of the skateboard while  FIGS. 7B ,  7 D, and  7 F show the front the skateboard. 
         [0033]      FIGS. 7A and 7B  show the skateboard and truck in a non-flexed position. The axel midpoint  99  is positioned directly along the longitudinal axis of the board.  FIGS. 7C and 7D  show the skateboard and truck in a partially flexed position. The flex or weight causes the first pivot assembly to rotate α degrees ( FIG. 7D ) out from the vertical axis while the second pivot assembly causes the hanger  103  to rotate β degrees ( FIG. 7C ) out of the longitudinal axis. As seen in  FIG. 7D , the axel midpoint  99  has shifted in the direction of the turn. 
         [0034]    Figures E and  7 F show the skateboard and truck in a heavily flexed position. The flex or weight causes the first pivot assembly to rotate α degrees ( FIG. 7F ) out from the vertical axis while the second pivot assembly causes the hanger  103  to rotate β degrees ( FIG. 7E ) out of the longitudinal axis. As seen in  FIG. 7F , the axel midpoint  99  has shifted significantly in the direction of the turn. 
         [0035]    For comparison, a standard skateboard truck might see movement of the axel midpoint during a turn move plus or minus ¼ of an inch relative to the longitudinal axis. In contrast, the dual pivot assembly design of the present invention enables the axel midpoint during a turn to move plus or minus 2 inches relative to the longitudinal axis. This significantly greater axel midpoint movement helps to keep the center of the truck under the center of gravity of the rider making the skateboard more stable. The axel midpoint for a single axel design would be the midpoint of the single axel. The axel midpoint for a hanger design which uses a left and right axel would be the midpoint as if the two axels were connected as one or the midpoint of the axis through the two axels. Although the design depicted in the images shows a hanger  103  with two axels  109 , the system could use a single axel design without deviating from the scope of the invention. 
         [0036]    The present invention also includes an offset axle or axels  109  that may extend beyond the width of the skateboard deck. This offset axle  109  allows for the wheels  139  to move in the direction the rider is leaning. For example, if the rider shifts his weight to the right intending for the skateboard to make a right turn, the right front wheel moves behind the left front wheel (axel rotation) and the right back wheel moves in front of the left back wheel. At the same time, the entire axle assembly moves to the right moving the midpoint  99  toward the weight of the rider. By swinging the axle and wheels towards the direction of the turn, the wheels are shifted away (more to the right) from the side of the skateboard and eliminating or reducing wheel bite. 
         [0037]    The offset axle  109  configuration also provides additional stability to the skateboard. When shifting the rider&#39;s weight to one side of the board, the shifted axel midpoint or truck center of gravity helps to offset the shifted center of gravity of the rider. Since the truck is configured with two pivot assemblies, the axle  109  and wheels  139  move in the direction the rider is leaning allowing the center of gravity of the truck to remain under the rider giving him much more stability while turning the skateboard. 
         [0038]    The foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present method and product disclosed herein. While the invention has been described with reference to various embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Further, although the invention has been described herein with reference to particular means, materials, and embodiments, the invention is not intended to be limited to the particulars disclosed herein; rather, the invention expands to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. Those skilled in the art, having the benefit of the teachings of this specification, may affect numerous modifications thereto and changes may be made without departing from the scope and spirit of the invention in its aspects.