The present invention relates generally to vehicles that employ an axle or axle assembly that pivots relative to the vehicle to permit turning thereof and, more specifically, to a truck assembly that prevents the axle or axle assembly from pivoting beyond a specified angle relative to the vehicle. Such a truck assembly is of use for skateboards or other recreational vehicles to secure the wheels thereto.
A skateboard typically comprises an elongated platform with a pair of truck assemblies secured at opposite ends to the underside of the platform. Each truck assembly typically comprises a base that is non-moveably secured to the platform and a hanger assembly, which includes an axle, that is moveably secured to the base by means of a kingpin bolt such that the hanger assembly can pivot along the axis of the kingpin bolt relative to the base and the skateboard platform. The hanger and base of a typical skateboard truck assembly is formed of a durable and light-weight material such as cast aluminum and the axle and kingpin bolt are constructed of an extremely durable material such as hardened steel.
A pair of wheels can be secured at opposite ends of the axle. When a skateboarder shifts his weight to one side of the skateboard platform, the hanger assembly pivots relative to the platform and makes the distance between the wheels, whose plane of rotation remains unchanged relative to the axis of the axle, on that side of the platform shorter than the distance between the wheels on the other side of the platform, thereby causing the skateboard to turn.
The ability to adjust the steering responsiveness of a skateboard truck assembly is very important since different skateboarders may prefer a different steering responsiveness and even the same skateboarder may prefer a different steering responsiveness at different times. A desired steering responsiveness can be achieved by tightening or loosening a kingpin nut secured to the threaded end of the kingpin bolt of the truck assembly, which determines the ease at which the hanger assembly pivots along the axis of the kingpin bolt relative to the base and platform. Tightening the kingpin nut increases the resistance of the axle to pivot and makes the skateboard less willing to turn. Likewise, loosening the kingpin nut decreases the resistance of the axle to pivot and makes the skateboard more willing to turn.
There have been several truck assemblies previously proposed that can be used to secure wheels to a vehicle such as a skateboard and permit turning thereof.
U.S. Pat. No. 6,793,224 (Stratton) discloses a skateboard truck that pivots about two axes and provides a combination of adjustable lateral stability and enhanced turning abilities.
U.S. Pat. No. 6,547,262 (Yamada and Hiranuma) discloses a skateboard truck assembly in which the pivot arm of the truck hanger rotates freely in a bearing assembly supporting the pivot arm in the socket hub.
U.S. Pat. No. 6,523,837 (Kirkland) discloses an adjustable truck assembly for skateboards with a retainer that provides a large turning radius for the axle, a highly predictable turning performance, and tool-less adjustment of the turning performance.
U.S. Pat. No. 6,474,666 (Andersen and Andersen) discloses a shock-absorbing skate truck assembly that includes a resilient shock absorber at the kingpin located between the assembly base of the assembly and the axle support member for absorbing shocks encountered during use and another shock absorber that is located in a recess of the assembly base and is engaged by an axle support member arm.
U.S. Pat. No. 6,443,471 (Mullen) discloses a truck assembly configured to eliminate undesired ride characteristics such as hanger-jiggle and wheel bite without sacrificing the skateboard's steering responsiveness, which generally comprises an axle assembly with a ring-shaped hanger that is confined on a kingpin using a pair of bushings, at least one of which includes an annular flange that projects into an annular gap that is defined between the hanger and the kingpin.
U.S. Pat. No. 6,428,023 (Reyes and Horn) and U.S. Pat. No. 6,315,312 (Reyes and Horn) disclose a truck assembly including a housing adapted to be mounted to a skateboard or the like, which generally comprises an axle bracket that is mounted for rotation transverse to the longitudinal axis and that includes a projecting upper end portion and a bottom end portion adapted to receive a transversely extending axle and wheel assembly, a resilient member located at least partially in the housing that is adapted to resist transverse rotation of the axle bracket and provide a restoring force, and a wedge member that has an aperture configured for receiving the projecting upper end portion of the axle bracket to establish a direct coupling therebetween.
U.S. Pat. No. 6,367,819 (Andersen and Andersen) discloses a shock-absorbing skate truck assembly including a resilient shock absorber at the kingpin located between the assembly base of the assembly and the axle support member for absorbing shocks encountered during use.
U.S. Pat. No. 6,318,739 (Fehn, Jr.) discloses a suspension assembly for a skateboard which generally comprises a base plate with a truck plate pivotally attached at one end with a shock absorber located between the base plate and the truck plate and further with a projection on the base plate that protects the shock absorber and aids the rider in performing tricks.
U.S. Pat. No. 6,315,304 (Kirkland et. al.) discloses an adjustable truck assembly for a skateboard, which generally comprises an axle housing, a base, a kingpin connecting the axle housing and base, a turning mechanism between the axle housing and base around the kingpin consisting of opposed cam surfaces that are angled along the axis of the kingpin and an elastomeric bushing so that rotating the axle housing about the kingpin pushes the cam surfaces apart against the compression pressure of the elastomeric bushing, and an adjustment mechanism for adjusting the pressure against the bushing.
U.S. Pat. No. 6,224,076 (Kent) and U.S. Pat. No. D439,945 (Kent) disclose a pneumatic compression strut skateboard truck that utilizes a pneumatic compression strut suspension system, which is of the same type and kind used in automobiles and other mechanical devices employing shock absorbing technology.
U.S. Pat. No. 6,182,987 (Bryant) discloses a truck assembly with replaceable axles and ball joint pivots that incorporates precision steering and rocking components for consistency and accuracy during maneuvers, a method for removing or replacing worn or broken axles, and a precision ball pivot pin that acts as the associate pivotal and rocking mechanism for the truck assembly.
U.S. Pat. No. 5,971,411 (Jones and Jones) discloses a skateboard truck, which generally comprises an extruded skateboard truck base that has an angled aperture for a cushion on which a hanger rests and a pivot bolt that holds the hanger to the base and that allows weight placed on either side of the skateboard to put pressure on the cushion to facilitate a turn.
U.S. Pat. No. 5,263,725 (Gesmer and Haug) discloses a skateboard truck that incorporates exceptionally rapid and consistently accurate axle rebound to the straight-ahead position, consistent and predictable steering response, an improved balance between stability and maneuverability, fine steering control, and a wide range of steering radii, which generally comprises a yoke, a pivot pin, and coil springs.
U.S. Pat. No. 4,398,734 (Barnard) discloses a truck design for a skate-type device involving turning and tilting axes of rotation, which generally comprises a T-shaped rod, the top part being housed in a base plate and the leg passing through a slot in the base plate, a resilient pad, washers, an axle yoke, and an adjustable lock nut.
U.S. Pat. No. 4,251,087 (Hansen) discloses a truck apparatus for skate and skateboard devices, which generally comprises an elongated kingpin, a means for affixing the upper end of the kingpin to the bottom of a load carrying platform, a wheel axle carriage assembly pivotally affixed to the lower end of the kingpin and adapted to rotate about the axis of the kingpin, a resilient drag sleeve and turn restoring element compressively disposed between the first and second friction surfaces, and a lock nut for selectively urging the carriage assembly towards the mid-portioned member so as to compress the drag sleeve between the first and second friction surfaces such that the carriage assembly may be resistively and partially resiliently rotated about the axis of the kingpin.
U.S. Pat. No. 4,185,847 (Johnson) and U.S. Pat. No. 4,176,850 (Johnson) disclose skateboard trucks that carry a plurality of wheels mounted in independent suspension, which generally comprise longitudinally extending arms that carry the wheel axles forwardly or rearwardly relative to a mounting that secures the arms in rotatable fashion to the trucks and that are resiliently biased by means of separate springs or torsion bars.
U.S. Pat. No. 4,184,693 (Whitmarsh) discloses a skateboard truck, which generally comprises a base plate for securing to the underside of a skateboard platform and a spring member, such as a plate spring, that is joined to the base plate by one end and carries a wheel axle near an opposite end.
U.S. Pat. No. 4,166,629 (List) discloses a skateboard truck, which generally comprises a base that has a first portion with a first hole therein and a second portion with a second hole therethrough, a hanger that has an axle for mounting wheels thereon, a ring and a pin, the pin being received in the first hole, and a coupling assembly for coupling the hanger to the base.
U.S. Pat. No. 4,152,001 (Christianson) discloses a truck for a skateboard or the like, which generally comprises an S-shaped leaf spring that attaches to the skateboard and, through a pivot pin, carries a transverse axle-supporting member at the opposite end and further generally comprises a pair of upwardly and inwardly inclined compression springs that are engaged by a pin carried by the leaf spring to resist pivotal movement of the leaf spring relative to the axle-supporting member.
U.S. Pat. No. 4,103,917 (Widolf) discloses a skateboard truck, which generally includes a wheel housing resiliently mounted on a skateboard truck base by means of a fastener which extends through the housing and is threaded onto a stud fixed to the base to compress a tubular cushion between the housing and the base, in which the fastener has a square cross-section that mates with a square bore in the cushion so that rotation of the fastener with respect to the cushion is prevented except when the retainer is manually and forceably rotated to adjust the compression on the cushion.
Although these prior art truck assemblies are capable of securing wheels to a vehicle such as a skateboard and permit turning thereof, they suffer from one or more disadvantageous properties. Skateboarders have become accustomed to the general shape and form of a typical skateboard truck assembly, so much that many of the maneuvers a skateboarder performs relies on this general property. Therefore, the above previously proposed truck assemblies that deviate significantly from the general shape and form of a typical skateboard truck assembly are highly undesired.
The remaining above previously proposed truck assemblies that do not deviate significantly from the general shape and form of a typical skateboard truck assembly have a design flaw that can result in an undesired ride characteristic called wheel bite. When a skateboarder uses his skateboard to perform maneuvers, such as riding off an obstacle, his balance may not be completely centered upon the skateboard platform. Such an uneven distribution of weight can cause the hanger assembly to pivot through a great angle relative to the platform and cause the wheels to contact the platform, called wheel bite. Wheel bite can cause the wheels to stop rotating and the skateboard to stop moving, and often causes the skateboarder to fall. The only way to prevent wheel bite is to tighten the kingpin nut to sufficiently retard the pivoting action of the hanger assembly, but this inhibits the steering responsiveness of the skateboard and is therefore highly undesired. Although U.S. Pat. No. 6,443,471 (Mullen) claims to solve wheel bite by providing a bushing with an annular flange, it still relies on the tightness or looseness of a kingpin nut to function and therefore affects the steering responsiveness of the skateboard. Furthermore, because the device of U.S. Pat. No. 6,443,471 (Mullen) is comprised of a soft material, it cannot completely prevent wheel bite.
Accordingly, what is desired, and has not heretofore been developed, is a truck assembly that has the same general shape and form of a typical skateboard truck assembly but can prevent wheel bite without affecting the steering responsiveness of the skateboard. Furthermore, because a skateboard can be configured with differently sized wheels and because skateboard platforms can have different degrees of concavity such that the angle through which the hanger assembly must pivot to cause wheel bite can be different for different skateboards, what is desired, and has not heretofore been developed, is a skateboard truck assembly in which the maximum angle through which the hanger assembly can pivot is easily adjusted by the user.
It is an object of the present invention to provide a skateboard truck assembly that prevents wheel bite.
It is an object of the present invention to provide a skateboard truck assembly wherein the maximum angle through which the hanger assembly can pivot relative to the skateboard platform is easily adjusted by the user.
It is an object of the present invention to provide a skateboard truck assembly wherein the maximum angle through which the hanger assembly can pivot relative to the skateboard platform is independent to its pivot sensitivity and therefore independent to the steering responsiveness of the skateboard.
It is an object of the present invention to provide a skateboard truck assembly that is inexpensive to manufacture.
It is an object of the present invention to provide a skateboard truck assembly that is easy to use.
It is an object of the present invention to provide a skateboard truck assembly that does not deviate significantly from the general shape and form of typical skateboard truck assembly.
It is an object of the present invention to provide a skateboard truck assembly whose turning responsiveness does not deviate significantly from that of a typical skateboard truck assembly.
The above comments apply equally to any vehicle that employs a hanger assembly that pivots relative to the vehicle to permit turning thereof. Furthermore, the above comments apply equally to any wheel-securing, blade-securing, or other device-securing assembly that employs a pivoting axle or axle assembly for which it is desired to specify a maximum angle through which the axle or axle assembly can pivot relative to the vehicle while not affecting the pivot sensitivity of the axle or axle assembly.
The above objects, features, and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings, which illustrate by way of example, the principles of the invention. The same reference numerals are used to identify the same or similar parts in each of the accompanying drawings.
a is a perspective view of the two set screws used in the first embodiment of the present invention,
a and
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In the above-described prior art skateboard truck assembly 1 the ease at which the hanger 3 can pivot along the axis of the kingpin bolt 5 relative to the base 2 is determined by how tightly the flange 13 is sandwiched between the upper bushing 7 and lower bushing 8. To increase the resistance of the hanger 3 to pivot along the axis of the kingpin bolt 5 relative to the base 2, which decreases the steering responsiveness of the skateboard, the kingpin nut 6 is tightened such that increased pressure is applied to the flange 13 by the upper bushing 7 and lower bushing 8. Likewise, to decrease the resistance of the hanger 3 to pivot along the axis of the kingpin bolt 5 relative to the base 2, which increases the steering responsiveness of the skateboard, the kingpin nut 6 is loosened such that decreased pressure is applied to the flange 13 by the upper bushing 7 and lower bushing 8. Although it is highly desired for a skateboard to have a sensitive steering responsiveness, the required decreased resistance of the hanger 3 to pivot can result in the hanger 3 pivoting through a great angle along the axis of the kingpin bolt 5 relative to the base 2 such that the wheels, which are secured to the ends of the axle 4, contact the underside of the skateboard platform, called wheel bite.
a shows an elevation view of a pair of set screws 14 that are part of the first embodiment of the present invention, whose purpose is to stop the hanger 3 and axle 4, like those shown in
a shows the position of each set screw 14 when it is fully actuated into its respective threaded bore 15, in which the end of each set screw 14 is nearly contacting or contacting the modified kingpin bolt 33. Likewise,
An extended flange 16 is defined in the ring-shaped member 29 of the hanger 3 that reduces the gap between the ring-shaped member 29 and the modified kingpin bolt 33 on either side of the modified kingpin bolt 33 in the direction perpendicular to the axis of the axle 4. When the hanger 3 pivots through a specified angle along the axis of the modified kingpin bolt 33 relative to the base 2 and causes one or both set screws 14 to contact the modified kingpin bolt 33, which resists any further pivoting of the hanger 3 beyond that angle, the extended flange 16 prevents the hanger 3 from moving relative to the modified kingpin bolt 33 in the plane of the ring-shaped member 29 in the direction generally perpendicular to the axis of the axle 4.
a through
Because the actuation of each set screw 14 into its threaded bore 15 or the actuation of each set screw 14 out from its threaded bore 15 is in a direction generally perpendicular to the axis of the modified kingpin bolt 33 (or kingpin bolt 5 if a modified kingpin bolt 33 is not used), the maximum angle through which the hanger 3 and axle 4 can pivot along the modified kingpin bolt 33 relative to the base 2 is independent to the tightness or looseness of the kingpin nut 6 secured to the threaded end of the modified kingpin bolt 33, and is therefore independent to the steering responsiveness of the skateboard.
If the thickness of the flange 13 or extended flange 16 is not increased to be be larger than the diameter of the set screws 14, a channel 28, which is shown in
It is apparent that various modifications can be made to the first embodiment of the present invention described above without departing from the spirit and scope of the invention. For example, although each set screw 14 shown in
a shows the generally perpendicular position of the c-shaped element 17, the wedge element 18, and the screw 19 relative to the axis of the kingpin bolt 5 when the screw 19, whose head rests between a first flange 22 and a second flange 23 that are both defined in the second bore 21 of the hanger 3, is actuated such that the wedge element 18, to which it is engaged, is pushed towards the kingpin bolt 5, causing the c-shaped element 17 to close in towards the kingpin bolt 5. Likewise,
Actuating the screw 19, whose head rests between a first flange 22 and a second flange 23, causes the elongated element 26 to move relative to the kingpin bolt 5, which is routed through the trapezoidal-shaped bore 27 defined in the elongated element 26, such that the kingpin bolt 5 can be positioned at different locations within the trapezoidal-shaped bore 27. Because a void will exist between the upper bushing 7 and lower bushing 8 on the exterior of the elongated element 26 when the elongated element 26 is moved nearer to the head of the screw 19, an upper bushing lower washer 24 is placed below the upper bushing 7 and a lower bushing upper washer 25 is placed above the lower bushing 8 in addition to the upper bushing upper washer 9 that resides above the upper bushing 7 and the lower bushing lower washer 10 that resides below the lower bushing 8. The kingpin nut 6 is secured to the threaded end of the kingpin bolt 5 to secure the hanger 3 to the base 2. The pivot stem 30 extends into the pivot cup 12 that rests in a recess 31 defined in the base 2.
a and
Although several specific embodiments of the present invention have been illustrated and described, many variations or modifications would be apparent that do not depart from the spirit and scope of the invention, which are defined by the appended claims.