Abstract:
A truck assembly for a skateboard, having a body for mounting to the underside of a skateboard deck. The body supports an axle and wheels mounted for pivoted movement for steering and includes adjustment means for varying steering characteristics of the skateboard. The axle may be mounted by a pair of opposite trunnions which define a pivot axis for the axle. The pivot axis is adjustable by a rotatable boss, preferably with a pivot arm which may be locked in place by a spring loaded pin inserted into a selected aperture. The truck may include two pairs of angled springs which are arranged similar to adjacent sides of a triangle and adapted to centre the axle. The truck assembly may include a removable spacer locatable between the deck and axle and extension pieces for the axle.

Description:
TECHNICAL FIELD  
         [0001]    This invention relates to truck assemblies for skateboards or other similar vehicles and in particular to a truck assemblies which enable steering characteristics of a skateboard or other similar vehicle to be varied.  
         BACKGROUND ART  
         [0002]    Skateboards in many different designs have developed since introduction of the basic skateboard configuration. In the basic structure, the skateboard comprises a deck having on its lower side front and rear truck assemblies, each of which supports opposite pairs of wheels on a transversely extending axle. The axles are mounted for pivotal movement about axes which extend at an obtuse angle to the plane of the skateboard deck and usually, the pivot axes of the axles of the front and rear truck assemblies are of an opposite inclination. Skateboards are therefore able to be steered by the rider leaning or shifting his or her weight to one side or other of the board thereby pivoting the deck of the skateboard in opposite directions relative to the longitudinal axis of the skateboard, this causing fore and aft pivotal movement of the wheel axles in opposite directions. Usually the skateboard truck assemblies incorporate resilient pads which resist pivoting the axle of the wheels and tends to return the wheels to a neutral position.  
           [0003]    More recently longboard skateboards have been introduced which include a deck of extended length. Skateboards of this type also incorporate truck assemblies however some difficulties are associated with steering of this type of board and maintaining their stability during a number of particular riding techniques if conventional truck assemblies are used. It is also desirable to enable adjustment of the steering characteristics of this type of skateboard to suit different applications. For this purpose it has been known to place an angled or wedge-shaped shaped packer between the skateboard truck assembly and the underside of the skateboard deck to adjust the pivot axis of the truck assembly axle and to raise the height of the skateboard deck above the axle line. This procedure however is obviously time-consuming as it involves removal of the track assembly and then reassembling with the use of the angled packer between the truck assembly and board. A further disadvantage is that each time a different angle is required for the plane of operation of the axles of the skateboard wheels, a packer of a different angle is required. Riders also fit different trucks from different manufacturers that have different pivot angles to either front or rear locations to achieve the steering stability or maneuvering characteristics they need for a particular style of riding.  
           [0004]    Other truck assemblies have means for varying the type or characteristics of the resilient pads used to resist pivotal movement of the wheel axles such that for example a greater or lesser weight is required to be applied to one side or other of the skateboard deck to obtain the same steering movement of the skateboard truck assemblies. These systems however have disadvantages as steering then becomes dependent on the weight applied and as a result control is compromised.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention aims to provide an improved truck assembly particularly suited for us with longboard type skateboards but which is also suited to use with other forms of skateboard or other rideable vehicle. In a particular aspect the present invention aims to provide a truck assembly in which the steering characteristics of the truck assembly can be selectively varied in a simple and effective manner. The present invention in a further aspect aims to provide a skateboard incorporating truck assemblies according to the present invention. In yet a further aspect, the present invention aims to provide an improved method and means for mounting a truck assembly to a deck of a skateboard or other rideable vehicle. Other objects and advantages of the invention will become apparent from the following description.  
           [0006]    The present invention thus provides, in a first preferred aspect, a truck assembly for use with skateboards, said truck assembly having a main body adapted to be mounted to the underside of the deck of said skateboard, an axle for supporting a pair of skateboard wheels, means for mounting said axle to said main body in such a manner as to allow pivotal movement of said axle in a plane and in opposite directions relative to said body to effect steering of said skateboard and means for selectively adjusting said plane of movement of said axle whereby to enable the steering characteristics of said skateboard to be varied.  
           [0007]    The term “skateboard” as used herein includes conventional skateboards, longboard skateboards or any other rideable vehicle which uses truck assemblies.  
           [0008]    Preferably pivot means mount the axle to the main body and define an axis of pivotal movement of the wheel axle and therefore the plane of pivotal movement of the wheel axle. The pivot means is suitably provided intermediate opposite ends of the wheel axle and adjustment means are suitably provided for selectively adjusting the pivot means to adjust the plane of movement of the wheel axles. Typically the axis of the pivot means lies in a plane extending longitudinally of and normal to the plane of the skateboard deck and the adjustment means adjusts the position of the axis of the pivot means in that plane. This adjustment may also adjust the plane of movement of the wheel axle which may be normal to the axis of pivotal movements.  
           [0009]    The pivot means in one preferred form may comprise a pair of opposite trunnions and means is provided for supporting the trunnions to the main body for rotation about the pivot axis of the pivot means to allow the axle of the wheels of the truck assembly to move in their plane of movement. Preferably, the trunnions support means are adjustable to enable variation of the pivot axis of the trunnions. Means may be provided for the unrestricted adjustment of the position of the trunnion support means and therefore unrestricted adjustment of the plane of pivotal movement of the axle of the truck assembly. Alternatively means may be provided for adjustment of the position of the trunnions support means and therefore plane of pivotal movement of the axle of the truck assembly to one of a number of discrete positions.  
           [0010]    Preferably, the trunnions support means comprises an adjustable support boss mounted to the truck body for rotational movement about an axis extending substantially normal to the longitudinal axis of the skateboard and parallel to the deck of the skateboard. The axle which supports the skateboard wheels may beconcentric to the axis of rotational movement of the boss when the axis is in a “neutral” position. The trunnions support boss may be journalled to the truck body or supported by any suitable bearing or bush arrangement to the truck body. The trunnions may typically be supported for rotation in bearings or bushes in the support boss. The support boss may be provided with an adjustment arm and means may be provided for adjusting the position of the adjustment arm to thereby adjust the rotational position of the support boss and the pivot axis of the trunnions. In one form, a series of locating means may be provided to locate and define different positions of the adjustment arm. The locating means may for example be in the form of a plurality of stops, apertures, markers or indicators. The adjustment arm may include means which cooperate with, or which may be aligned with, a selected stop, aperture, marker or indicator to set or locate the position of the adjustment arm and boss. For example where the locating means are in the form of a plurality of apertures, the adjustment arm may include a pin which can locate in a selected aperture. The pin may be spring loaded to cooperate with a selected aperture to securely locate and hold the arm in a selected position. The pin may have an enlarged head which facilitates its detachment from a selected aperture. Most preferably, the arm extends generally radially relative to the axis of rotational movement of the boss and the locating means are arranged along an arc or curve on the main body of the truck assembly.  
           [0011]    Biasing means are suitably provided for opposing movement of the axle of the wheels of the truck assembly in its pivot plane. The biasing means may be provided between the axle and truck body. Preferably, the biasing means comprise springs which may comprise coiled springs or other elastic or resilient means. Most preferably, pairs of springs or resilient means are provided on both sides of the main body and extend between, and are connected to, the main body and axle.  
           [0012]    Preferably, the truck assembly is adapted to be mounted to the skateboard deck via a mounting member. Preferably, the truck assembly is detachably engageable with the mounting member. A spacer may also be provided between the truck assembly and mounting member, the spacer being detachably engageable with the truck assembly and mounting member. Spacers of various thickness may be provided to vary the spacing of the truck assembly from the skateboard deck.  
           [0013]    The present invention in a further aspect provides a skateboard having a deck and a pair of truck assemblies secured to the underside of said deck, each said truck assembly having an axle supporting a pair of wheels, said axle being mounted to said skateboard deck for pivotal movement in a plane to allow steering of said skateboard and there being provided means for selectively adjusting said plane of pivotal movement of said axles of said truck assembly to enable variation of the steering characteristics of said skateboard.  
           [0014]    The present invention in a further preferred aspect provides a truck assembly for use with skateboards, said truck assembly having a main body, and mounting means for mounting said main body to the deck of said skateboard, said mounting means comprising a first mounting member adapted to be mounted directly to the underside of the deck of said skateboard, said first mounting member having means for cooperating with said truck assembly for mounting said truck assembly to said skateboard, or with a spacer for mounting said truck assembly via said spacer to said skateboard deck.  
           [0015]    Preferably, the truck assembly is slidably engageable with the mounting member and/or spacer and the spacer is slidably engageable with the mounting member. The axles may be lengthened by threading an extension section in place of the wheels which may be locked in place by shallow tapers machined in the axle and the extension section. The wheels may be located at the ends of the extension section.  
           [0016]    Preferably, the first mounting member has coupling means complementary to the means on the truck assembly and spacer means whereby the first mounting part may be coupled to the truck assembly or spacer means. Further complementary coupling means are suitably provided between the spacer means and truck assembly to enable them to be coupled together. The complementary coupling means may comprise a complementary rib/groove configuration which permits the components to be slidably engaged. Releasable latch means may be provided for latching the components together in a desired combination. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein:  
         [0018]    [0018]FIG. 1 is a perspective view of a truck assembly according to an embodiment of the invention;  
         [0019]    [0019]FIG. 2 illustrates in a dissembled view the truck body of the truck assembly and associated mounting block and spacer;  
         [0020]    [0020]FIGS. 3 and 4 illustrate in side and front views, the steering adjustment boss of the truck assembly;  
         [0021]    [0021]FIG. 5 illustrates a skateboard provided with a pair of truck assemblies according to an embodiment of the invention;  
         [0022]    [0022]FIG. 6 illustrates portion of the skateboard of FIG. 5 from the front;  
         [0023]    FIGS.  7 ( a ), ( b ) and ( c ) illustrate respectively one position of the steering adjustment boss and the steering effect achieved when the skateboard is tilted shown schematically in front and top views; and  
         [0024]    FIGS.  8 ( a ), ( b ) and ( c ) illustrate respectively a second position of the steering boss and the steering effect achieved when the skateboard is tilted shown schematically in front and top views. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    Referring to the drawings and firstly to FIGS. 1 and 2, there is illustrated a truck assembly  10  according to an embodiment of the invention primarily designed for use with longboard skateboards but which may be used with smaller size skateboards or any other similar rideable vehicle. The truck assembly  10  includes a main truck body  11  which is adapted to be mounted to the underside of the deck of a skateboard via a mounting block  12  which may be secured by bolts, screws or fasteners to the skateboard deck and with or without an intermediate spacer  13 . Complementary coupling means are provided on the truck body  11 , mounting block  12  and spacer  13  which allow them to be slidably interengaged. Thus the truck body  11  may be slidably engaged directly with the mounting block  12  or the truck body  11  may be slidably engaged with a spacer  13  which is slidably engaged with the mounting block  12 . Thus spacers  13  of different thickness may be provided to enable different spacings of the truck body  11  from the skateboard deck.  
         [0026]    The complementary coupling means comprise a rib and groove type coupling comprising a pair of opposite parallel ribs or edges  14  and  14 ′ on the lower side of the truck body  11  and spacer  13  and a pair of opposed parallel grooves  15  and  15 ′ on the upper side of the spacer  13  and mounting block  12 . The ribs  14  and  14 ′ and grooves  15  and  15 ′ are at substantially the same lateral spacing such that the truck body  11  may be slid longitudinally onto the mounting block  12  or spacer  13  through the cooperation between the opposed ribs  14  or  14 ′ and grooves  15  or  15 ′ and similarly the spacer  13  may be slid longitudinally onto the mounting block  12  through the cooperation between the opposed ribs  14 ′ and grooves  15 ′. The truck body  11  is maintained in engagement with the mounting block  12  or spacer  13  by latching devices comprising a latching member  16  and  16 ′ on a spring or resilient finger  17  and  17 ′ fixed to the mounting block  12  or spacer  13 . The latch members  16  and  16 ′ are adapted to locate in a recess  18  on the underside of the truck body  11  and the latch member is adapted to located in a recess  18 ′ on the underside of the spacer  13  to retain the body  11  to the block  12  or spacer  13 , or spacer  13  to the mounting block  12 . The body  11  may be detached from the block  12  or spacer  13  or the spacer  13  may be detached from the mounting block  12  by pushing the free end of the finger  17  or  17 ′ downwardly to release the latch member  16  or  16 ′ from the recess  18  or  18 ′ to allow the truck body  11  to be slidably disengaged from the mounting block  12  or spacer  13 , or spacer  13  from the mounting block  12 . Assembly is a reverse of the above except that the truck body  11  may be pushed onto the block  12  or spacer  13  until the latch member  16  or  16 ′ under the influence of the spring finger  17  or  17 ′ locates within the recess  18  and similarly for engagement of the spacer  13  with the mounting block  12 .  
         [0027]    The truck body  11  includes a transversely extending bore  19  which is sized to accept a steering adjustment boss  20  (see also FIGS. 3 and 4) which is supported rotatably in the bore  19  by being inserted from one side thereof and which is retained by means of a circlip  21  on the opposite side such that the boss  20  is capable of rotation about the axis  22  of the bore  19 , that axis  22  extending substantially normal to the longitudinal axis of the skateboard deck to which the truck assembly  10  is mounted. The boss  20  may be journalled in the bore  19  or mounted via bearings therein. The boss  20  is also provided with a central bore  23  which is coaxial with the bore  19  of the body  11 . The bore  23  is of a somewhat rectangular configuration and receives the main truck axle  24  which supports at opposite ends via bearings the wheels  25  of the truck assembly  10 . The rectangular shape of the bore  23  accommodates pivotal movement of the truck axle  24  as described further below.  
         [0028]    The truck axle  24  is mounted to the boss  20  by means of a trunnions arrangement comprising a pair of opposite trunnions  26  (see FIGS. 3 and 4) which are arranged intermediate the opposite ends of the axle  24  and which extend normal to the longitudinal axis of the axle  24 . The trunnions  26  may be defined by a pin inserted into a bore which extends transversely through the axle  24  and projects on opposite sides thereof. Alternatively the trunnions  26  may be defined by a pair of pins which are provided on opposite sides of the axle  24  and interconnected for example by a threaded connection through the axle  24 . Other arrangements however may be provided for defining the trunnions  26 . The trunnions  26  are supported in opposite bores  27  in the boss  20  via bearings  28  such as roller or ball bearings or bushes so as to allow for smooth pivoting movement of the axle  24  about the axis  29  of the trunnions  24 . The bores  27  may be closed on their outer sides by end caps. It will be apparent that in the position of FIG. 1, the longitudinal axis of the axle  24  is coaxial with the axis  22  of the bore  19 .  
         [0029]    The orientation of the pivot axis  29  of the trunnions  26  can be adjusted however by rotation of the boss  20  in the bore  19  of the truck body  11 . To enable setting of position of the trunnions&#39;s pivot axis  29 , an arm  30  which is integrally formed with the boss  20  extends radially from the boss  20 . The free end of the arm  30  is provided with a spring loaded stop pin  31  which is normally urged by an internal spring  32  in the arm  30  to the position of FIG. 3 extending parallel to the axis  22  of the bore  19 . The pin  31  is provided with a head  33  to enable retraction of the pin  31  against the force of the spring  32 . The pin  31  may locate in one of a series of holes  34  provided at spaced apart positions along a curved member  35  of the body  11  which is centered on the rotational axis  22  of the boss  20 . To change the rotational position of the boss  20  relative to the truck body  11 , the pin  31  is retracted by grasping the pin head  33  and the arm  30  is then rotated in a desired direction to rotate the boss  20  arid reposition the stop pin  31  in alignment with another one of the holes  34  after which the pin  31  may be released to locate within that hole  34  to hold the arm  30  and boss  20  in a set position. It will be apparent that during this movement, axle  24  remains concentric with the axis  22  of the bore  19 .  
         [0030]    The boss  20  is also provided with relief grooves  36  and  37  extending from and on opposite sides of the bore  23  and in alignment with the arm  30 , the grooves  36  and  37  and the rectangular configuration of the bore  23  accommodating pivotal movement of the axle  24  in a plane  38  (see FIG. 4) perpendicular to the pivot axis  29  of the trunnions  26 . It will be appreciated that rotation of the steering boss  20  as described above will rotate the pivot axis  29  of the axle  24  as defined by the trunnions  26  to thereby vary the orientation of the plane  38  along which the axle  24  may pivot.  
         [0031]    To hold the axle  24  in a “neutral” position extending substantially at right angles to the truck body  11  and thus skateboard deck to which the truck assembly  10  is mounted, pairs of tension springs  39  are provided on opposite sides of the truck body  11  to extend between anchoring points  40  on the truck body  11  on either side of the axle  24 , and a lug  41  mounted to the axle  24  at a position spaced outwardly from the body  11 . The springs  39  provide a biasing force to resist pivotal movement of the axle  24  about the trunnions axis  29 . The springs are mounted at an angle to the axle in a triangular pattern so that their opposing resistance to the body weight needed to tilt the deck to produce turning remains reasonably constant for the range of deck angles. This is achieved by reducing the angle between the angle and the spring attachment or the truck body as the desk is tilted to adjust steering. The constant load assists in maintaining an even downward force on all four wheels during hard turning and hence optimised wheel grip. With conventional trucks the rubber or spring arrangement increases with deck angle and shifts the bodyweight downward force to the inside wheels, loading the wheels unevenly and reducing the overall wheel grip. The axle  24  preferably comprises a central part  42  which carries or is connected to the trunnions  26  and detachable opposite end parts  43  which carry the wheels  25 . The end parts  43  may be threaded for threaded engagement with opposite ends of the central part  42  with the spring mounting lugs  41  arranged therebetween. This arrangement also allows different length end parts  43  to be substituted or removed completely for different applications or for supporting wheels  25  of different sizes or configurations.  
         [0032]    As shown in FIGS. 5 and 6, pairs of truck assemblies  10  are mounted at spaced apart fore and aft positions via respective mounting blocks  12  and spacers  13  (if required) to the underside of the deck  44  to form a skateboard  45  typically a longboard type skateboard. The positions of the steering bosses  20  of each truck assembly  10  may then be varied depending upon the steering characteristics required in the skateboard  45 . In the position shown in FIG. 1 and assuming that the truck assembly  11  is mounted to the deck  44  of the skateboard  44  such that the pivot axis  29  is parallel to the longitudinal axis  46  of the skateboard  45 , pivotal movement of the skateboard deck  44  will not cause any steering movement of the truck assembly  10  as the axle  24  will pivot in a plane at right angles to the skateboard axis  46 . Thus no fore and aft pivotal movement of the axle  24  results and thus no steering is achieved.  
         [0033]    Altering the plane of pivotal movement of the axle  24  by inclining the axis  29  of the trunnions  26  to the longitudinal axis  46  of the skateboard  44  will enable steering to be achieved. Thus if the arm  30  of the steering boss  20  is moved to a position where the stop pin  31  can locate in one of the holes  34  away from the central hole  34 ′ as for example shown in FIG. 7( a ), the pivot axis  29  of the trunnions  26  is accordingly pivoted such as to be inclined to the longitudinal axis  46 . Thus pivoting of the deck  44  as indicated by the arrows in FIG. 7( c ) during riding of the skateboard  45  by for example weight shifting will be translated into a clockwise pivoting movement of the axle  24  as shown in FIG. 7( b ) along the inclined plane indicated at  38  in FIG. 7( a ) and therefore steer the skateboard  45 . Where the skateboard deck  44  is pivoted in the opposite direction, the axle  24  will pivot in the inclined plane  38  in an anticlockwise direction to effect steering of the skateboard  45  in the opposite direction,  
         [0034]    If the arm  30  is further adjusted as shown in FIG. 8( a ) to position the trunnions axis  29  at an increased angle to the longitudinal axis  46  of the skateboard  45 , the possible plane  38  of movement of the axle  24  will, relative to the axis  46 , become increasingly acute such that pivoting of the skateboard deck  44  as for example indicated by the arrows in FIG. 8( c ) will result in increased fore and aft clockwise pivoting movement of the axle  24  and wheels  25  and thus sharper turning through a reduced turning circle.  
         [0035]    Of course the steering effect of both the front and rear truck assemblies  10  may be selectively varied by simply readjusting the position of the arm  30  by retracting the stop pin  31  and repositioning the pin  31  in one of the holes  34  with movement of the pin  31  outwardly from the center position resulting in a reduced turning circle or a sharper steering effect with the same pivotal movement of the skateboard deck  44 . The rider is therefore able in a simple and effective manner to selectively adjust the steering required for different circumstances or different applications.  
         [0036]    In the skateboard  45  as illustrated in FIG. 5, it will be seen that the steering adjustment arms  30  of the truck assemblies  10  are angled in opposite directions such that when the deck  44  is pivoted about the longitudinal axis  46 , the front and rear axles  24  will pivot in opposite directions. In some circumstances however it may be desirable to have only the front truck assembly  10  provide a steering function and thus the arm  30  of the rear truck assembly  10  in this instance is located in the central position as illustrated in FIG. 1 where the deck of the skateboard  45  is planar. In the skateboard  45  of FIG. 5 where opposite ends of the deck  44  are inclined upwardly, the arm  30  is adjusted such that it and the possible plane  38  of pivotal movement of the axle  24  are at right angles to the axis  46   
         [0037]    The truck assemblies  10  of the invention may be applied to skateboard decks of many different configurations and various steering characteristics of the skateboard can be achieved by simply adjusting the adjustment arms  30  in the manner described. Further handling characteristics can be varied by changing the spacers  13  or alternatively eliminating the spacers  13 . Further it will be appreciated that other arrangements may be provided for supporting the axle  24  of the truck assembly  10  such that the angle of its possible plane of pivotal movement can be adjusted to adjust the steering characteristics of the truck assembly  10 .  
         [0038]    Whilst the above has been given by way of illustrative embodiment of the invention, all variations and modifications thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.