US20180193722A1

US20180193722A1 - Highly maneuverable and controllable skateboard trucks

Info

Publication number: US20180193722A1
Application number: US15/859,186
Authority: US
Inventors: George William ILIFFE, III
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-12-30
Filing date: 2017-12-29
Publication date: 2018-07-12

Abstract

In one embodiment, a skateboard includes a pair of trucks mounted to the underside of a skateboard deck. Each truck includes a base plate, a hanger, axles and a kingpin. The base plate is secured to the underside of the deck. The base plate has a pivot recess that mates with the pivot on the hanger. The hanger includes a hanger pivot and the bushing seats. The pivot recess houses a pivot tube supporting the hanger pivot. The hanger pivot, pivot tube and the pivot recess are all in-line. In contrast, the hanger pivot axis is negatively offset relative to the pivot-to-axle axis.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims the benefit of U.S. provisional application no. 62/441,093, filed Dec. 30, 2016, entitled “Highly Maneuverable and Controllable Skateboard Trucks”, which application is incorporated herein in its entirety by this reference.

BACKGROUND

The present invention relates to highly maneuverable, controllable, lightweight and structurally superior trucks for skateboards
Traditional skateboards include a deck, trucks, wheels (typically with bearings), bushings (typically polyurethane), and nuts and bolts to fasten the truck and wheel assembly to the bottom of the deck. Modern decks vary in size, but most are 7 to 10.5 inches wide. Wider decks can be used for greater stability when transition or ramp skating. Standard skateboard decks are usually between 28 and 33 inches long.
Attached to the deck are two trucks (usually a metal alloy such as aluminum), which connect the wheels and bearings to the deck. Referring to the cross-sectional view of FIG. 1, inverted for easier reference, each truck 100 further composed of two main components. The bottom part of the truck 100 is screwed to the deck and is called the baseplate 110, and a hanger 140 is coupled to the baseplate 110. An axle 160 runs through the hanger 140, for mounting wheels (not shown).
Between the baseplate 110 and the hanger 140 are bushings 132, 134 that provide the cushion mechanism for turning the skateboard. The bushings cushion the truck when it turns. The stiffer the bushings, the more resistant the skateboard is to turning. The softer the bushings, the easier it is to turn. A bolt called a kingpin 120 holds these parts together and fits inside the bushings 132, 134. Thus by tightening or loosening a kingpin nut 122, the trucks can be adjusted loosely for better turning and tighter for more stability. Typical kingpin screw/nut size is ⅜″-24 tpi.
As discussed above, bushings 132, 134 are donut-shaped pieces that are inserted onto the kingpin 120. There are two bushings per truck, one bushing 132 above and the other bushing 134 below where the hanger 140 fits onto the kingpin 120. Adjusting the kingpin nut 122 to tighten or loosen the bushings 132, 134 will adjust the turning radius and response of the truck itself. Tighter bushings mean stiffer trucks and less chance of wheel bite, while loose bushings make for easier turning but a greater chance of wheel bite.
A hanger pivot 142 of hanger 140 is seated in a pivot cup 114 of base plate 110. The pivot cup 114 is a raised and hollowed receptacle on the base plate 110 opposite the kingpin 120. The pivot cup 114 in turn holds the pivot bushing 112. Typically, the pivot bushing 112 is a plastic cup-shaped piece which rests in the pivot cup 114 of the base plate and supports the hanger 140 at a pivot tip 144 (aka pivot point) allowing the truck 100 to pivot smoothly. The pivot bushing 112 prevents frictional contact between the truck and the base plate and provides a cushioned pivot point.
In conventional truck 100, as shown in FIG. 1, the pivot-to-axle axis 180 is substantially in-line with respect to an axis of the pivot cup 114, while the pivot-to-axle axis 180 about 45 degrees relative to the kingpin axis 190. The pivot-to-axle axis 180 runs from a pivot tip 144 through a midpoint of the axle 160. As shown in FIG. 1, pivot-to-axle axis 180 and kingpin axis 190 form an isosceles triangle with respect to bottom surface of the base plate 110, which in turn is coupled to the skateboard deck (not shown). While functional, this prior art truck 100 produces a relatively limited degree of turn. Turning is accomplished when a user focuses weight on one edge of the skateboard causing the truck 100 produce a twisting turn, thereby turning the skateboard in the desired direction.
In general, an axle width should be chosen that is close to the width of the deck it will be used with. For example, a 7.75″ wide deck will usually be fitted with trucks that have axles between 7.5″ wide and 8.0″ wide. Standard truck axle nut size is 5/16″-24 tpi UNF, and the thinner “jam” style with an optional nylon lock. Trucks that are too wide can make doing tricks difficult and can cause the wheels to get in the way when the skateboard is being ridden. Trucks that are too small can be hard to maintain stability and can cause wheel bite to occur when turning.
It is therefore apparent that an urgent need exists for skateboard trucks that are highly maneuverable and controllable thereby enabling skateboard riders to execute maneuvers and tricks that would otherwise require a much higher skill level.

SUMMARY

To achieve the foregoing and in accordance with the present invention, highly maneuverable, controllable, lightweight and structurally superior trucks for skateboards are provided.
In one embodiment, a skateboard includes a pair of trucks mounted to the underside of a skateboard platform (aka deck). Each truck includes a base plate, a hanger, axle(s) and a kingpin. The base plate is secured to the underside of the deck. The base plate has a pivot recess that mates with the pivot on the hanger. The hanger includes a hanger pivot and the bushing seats. The pivot recess houses a pivot tube supporting the hanger pivot. The hanger pivot, pivot tube and the pivot recess are all in-line. In contrast, the hanger pivot axis is negatively offset relative to the pivot-to-axle axis.
The kingpin projects downwardly from the underside of the base plate, from a location spaced from the pivot recess. The base plate has a substantially vertical facing surface adjacent to the pivot recess, on the side of the pivot recess opposite the kingpin. The kingpin is oriented at a predetermined angle toward the pivot recess. Both the kingpin and the pivot recess are aligned longitudinally with the skateboard platform.
The hanger includes a cylindrical channel configured to house at least one axle. The hanger also includes a pivot pin operatively coupled to the pivot tube housed inside the pivot recess. The hanger pivot axis, the pivot tube axis and the pivot recess axis are all inline. In contrast, the hanger pivot axis is substantially negatively offset relative to the pivot-to-axle axis.
Note that the various features of the present invention described above may be practiced alone or in combination. These and other features of the present invention will be described in more detail below in the detailed description of the invention and in conjunction with the following figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the present invention may be more clearly ascertained, some embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 depicts a vertical cross-sectional view depicting a conventional truck for a skateboard;

FIGS. 2A-2B are two perspective views depicting one embodiment of a highly maneuverable and controllable skateboard truck , in accordance with the present invention;

FIGS. 2C, 2D and 2E are side, bottom and top views, respectively, of the truck embodiment of FIG. 2A;

FIGS. 3A, 3B, 3C, 3D and 3E are the respective perspective view, side view, top view, bottom view and front view of an exemplary baseplate for the truck embodiment of FIG. 2A;

FIGS. 4A, 4B, 4C and 4D are the respective perspective view, top view, side view and bottom view of an exemplary hanger for the truck embodiment of FIG. 2A;

FIG. 5 is a perspective view of an exemplary axle for the truck embodiment of FIG. 2A;

FIG. 6A is a vertical cross-sectional view illustrating the rack of the truck embodiment of FIG. 2A;

FIGS. 6B-6E are additional cross-sectional views further illustrating the truck embodiment of FIG. 2A;

FIG. 7 is a graph depicting displacement under load for several prototypes of the truck embodiment of FIG. 2A; and

FIG. 8 is a graph illustrating responsiveness for the truck embodiment of FIG. 2A.

DETAILED DESCRIPTION

The present invention will now be described in detail with reference to several embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent, however, to one skilled in the art, that embodiments may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention. The features and advantages of embodiments may be better understood with reference to the drawings and discussions that follow.
Aspects, features and advantages of exemplary embodiments of the present invention will become better understood with regard to the following description in connection with the accompanying drawing(s). It should be apparent to those skilled in the art that the described embodiments of the present invention provided herein are illustrative only and not limiting, having been presented by way of example only. All features disclosed in this description may be replaced by alternative features serving the same or similar purpose, unless expressly stated otherwise. Therefore, numerous other embodiments of the modifications thereof are contemplated as falling within the scope of the present invention as defined herein and equivalents thereto. Hence, use of absolute and/or sequential terms, such as, for example, “always,” “will,” “will not,” “shall,” “shall not,” “must,” “must not,” “first,” “initially,” “next,” “subsequently,” “before,” “after,” “lastly,” and “finally,” are not meant to limit the scope of the present invention as the embodiments disclosed herein are merely exemplary.
The present invention relates to highly maneuverable, controllable, lightweight and structurally superior trucks for skateboards that is also cost effective to manufacture.
To facilitate discussion, FIGS. 2A-2B are two perspective views depicting one embodiment of a highly maneuverable and controllable skateboard truck 200, in accordance with the present invention, while FIGS. 2C, 2D and 2E are side, bottom and top views, respectively, illustrating the truck 200. Truck 200 includes a base plate 210, a hanger 240 and an axle 260.
The bottom portion of the truck 200, i.e., baseplate 210, is configured to be secured to a skateboard deck (not shown). In turn, hanger 240 is configured to be operatively coupled to the baseplate 210. Axle 260 is preferably a matching in-line pair of separate axles, i.e., split axles, for mounting wheels (not shown). Alternatively, axle 260 can through the hanger 240.
FIGS. 3A, 3B, 3C, 3D and 3E are the respective perspective view, side view, top view, bottom view and front view of an exemplary baseplate 210 for skateboard truck 200. FIGS. 4A, 4B, 4C and 4D are respective perspective view, top view, side view and bottom view of an exemplary hanger 240 for skateboard truck 200, while FIG. 5 is a perspective view of an exemplary axle 260 for skateboard truck 200. Finally, FIGS. 6A-6E depict various cross-sectional views of truck 200.
Referring now to FIG. 6A, a vertical cross-sectional view 600A depicting half of exemplary truck 200, located between baseplate 210 and hanger 240 are donut-shaped bushings 632, 634 that provide the cushion mechanism for steering the skateboard (not shown). These bushings 632, 634 cushion truck 200 as the skateboard turns. The stiffer the bushings 632, 634, the more resistant the skateboard is to turning. Conversely, the softer the bushings 632, 634, the easier it is to turn.
Kingpin 620 couples the hanger 240 and the baseplate 210 together by sandwiching hanger 240 between bushings 632, 634. A kingpin nut 622 can be adjusted loosely for better turning and tighter for more stability. In other words adjusting kingpin nut 622 to tighten or loosen bushings 632, 634 adjusts the turning radius and responsiveness of truck 200. Tighter bushings mean stiffer trucks and less chance of wheel bite, while loose bushings make for easier turning but a greater chance of wheel bite.
In this embodiment, during use hanger pivot 642 of hanger 640 is secured by a pivot recess 614 of base plate 210. The pivot recess 614 is a cylindrical hole machined through the base plate 210 and is located substantially opposite with respect to kingpin 620. The pivot recess 614 houses a pivot tube 612, a tubular insert whose bottom edge rests on a corresponding shoulder of the pivot recess 614. In turn, pivot tube 612 supports hanger 240 thereby allowing truck 200 to pivot smoothly, controllably and relatively aggressively.
As a result, the pivot tip 644 is freely suspended because a shoulder of hanger pivot 642 is fully supported along a corresponding top edge of pivot tube 612. The primary functions of pivot tube 612 are to prevent frictional contact between truck 200 and base plate 210 and to cushion hanger pivot 642, while providing superior control of the skateboard. Pivot tube 612 can be made from a suitably plastic, including lubricating polymer.
Pertinent to the working geometry of truck 200, the pivot-to-axle axis 682 (represented by dotted line BB-BB) and the pivot-recess axis 680 (represented by FF-FF) of the pivot recess 614 are substantially separated. Note that the pivot-to-axle axis 682 runs from the pivot tip 644 through a midpoint of the axle 260.
Whenever the rider focuses weight on one edge of the skateboard (not shown) the truck 200 will produce a twisting turn. With this novel structure, skateboard truck 200 enables the skateboard rider to maneuver in a controlled and more aggressive degree of turns necessary to perform trick and tight turns.

Advantages

In accordance with the present invention, improvements to the above described trucks, e.g., truck 200, result from superior features including: 1) Strength to Weight Ratio; 2) The Pivot Tube; 3) Non-Restrictive Open Bushing Seat; 4) Split Axle design; and 5) Rake.

Strength-to-Weight Ratio:

Truck 200 takes advantage of material removal to substantially reduce weight while maintaining structural integrity to provide major impacts that skateboarding demands. With lighter weight, truck 200 enables the skater to perform more flip tricks as a result of the skater being able to pop the skateboard higher thereby allowing the skilled skateboarder to achieve quicker response time.
Several prototypes of the truck 200 were strength-tested as depicted by the graph of FIG. 7 illustrating truck displacement under substantial load. These truck prototypes 1-4 were subjected to a steadily increasing force applied to each axle 260, and the force approached 5000 foot-pounds before the hanger 240 began to bend noticeably.
Truck 200 is designed to be high-strength relative to weight ratio (skateboard v. rider) result in a lower “angular moment/momentum”. Linear Momentum and Angular Momentum: p=mv where p=Ro m=mass and v=velocity are a function of Linear Momentum. As the overall mass of truck 200 is reduced, the Angular Momentum is lowered. A lower angular or linear momentum is an advantage in skateboarding due to the fact that it takes less force and momentum to achieve turning.

Pivot Tube:

Truck 200 exhibits a much more complex movement that is very dependent on the truck design geometry. It is characterized by both rotation and angulation at the pivot point 644. As discussed above, truck 200 includes a pivot tube 612 which is open-ended and preferably made from a self-lubricating WFB compound. Hanger pivot 642 accomplishes several functions, including providing a pivot point for turning, and also acting as a “thrust” bearing to keep the king pin 620 centered in the hanger 240. Without a contacting pivot end point, accomplished by using pivot tube 612, the responsibility for positioning the king pin 240 in the center of the bushing seat of hanger 240 now falls on the bushings 632, 634. Hence, not having a pivot end point front loads the bushings 632, 634 to support the hanger position. Coupled with a well-defined bushing seat, truck 200 advantageously enables the rider to execute quick smooth turns while providing instant feedback.
Existing cast truck or forged truck, e.g., truck 100, typically has an ill-defined or nonexistent, non-consistent bushing seats and thereby the pivot cup 112 is not capable of acting as a thrust bearing, often causing the area behind the pivot to collide and interfere with the base plate 110 potentially damaging both the hanger 140 and the baseplate 110 and resulting in a rough ride. This movement can also cause the bushings 132, 134 to come out of the seat causing a loss of control.
In stark contrast, the thrust aspect is significantly more pronounced in truck 200 due to its design geometry. The geometry of truck 200 lends itself to evenly split the responsibility to carry the load between the bushings 632, 634 and the hanger pivot 642. The durometer of the pivot tube 612 defines how much feedback you receive from the truck 200. The harder the pivot tube 612, the greater the feedback. In this embodiment, bushings 632, 634 can have a 96A durometer, a relatively hard material on the hardness scale. The softer the durometer of the pivot tube 612, the plusher the ride, the more forgiving they are and the feedback is now minimized.

Bushing Seat:

There are many different shapes and depths of bushing seat, but broadly speaking, it's the depth one needs to pay attention to. The deeper or more “restrictive” the bushing seat, the more pressure there is on the bushing, and the less the truck will turn. The shallower or more “open” the bushing seat, the less pressure there is on the bushing, and the more the truck will turn. A precise, open bushing seat lets the bushing do what it is designed to do, provide feedback within the trucks turning radius as well as critically aligning the hanger 240 around the kingpin 620. According, truck 200 includes a precision “open” bushing seat that enables truck 200 to respond very quickly to turns. Contrasting this to the existing trucks which are generally cast aluminum non-defined often with a restrictive bushing seat which yields a sluggish response feedback while turning.
Using a precise open bushing seat coupled with pivot tube 612 enables the hanger pivot 642 to act as thrust bearing allowing the truck 200 to turn smoothly with little to no interference between the bushing seat and bushings 632, 634. The reason for this is the pivot tube 612 functions as a thrust bearing which provides an axial load thereby aligning the hanger 240 perfectly with the bushings 632, 634.

Axle Configuration and Customizable Hanger Widths:

As discussed above, existing trucks are typically a cast or forged truck with a single axle through the entire length of the hanger. Instead of a single hanger, truck 200 includes a split axle design. The split axle design also enables the axles to be replaced to achieve wider or narrow hanger width, for example, 139 mm, 149 mm, 159 mm and 169 mm hanger widths. Another advantage of split axles is the weight aspect. By using two shorter length axles instead of one larger single axle contributes to the strength to weight ratio advantage of truck 200.

Enhanced Negative Rake:

By orientating truck 200 in a side view profile, illustrated by the cross-sectional view of FIG. 6A, Rake 690 is defined by the geometry of the center of axle 260 as it relates to the geometry of hanger 240 with respect to hanger pivot 642. More specifically, drawing a reference intersection line FF-FF through the center of the hanger pivot 642 on the hanger 240. In other words, Rake 690 is the relationship of line FF-FF to the center of the axle 260.
In this embodiment, truck 200 has a pronounced negative Rake 690, as alternatively defined by the substantial separation of the pivot-to-axle axis 682 (BB-BB) relative to the pivot-recess axis 680 (FF-FF). Negative Rake 690 occurs when the center of the axle is oriented “behind” the intersection line FF-FF.
Advantages of truck 200's substantially pronounced negative rake include the ability to execute consistent truck turns, resulting in very predictable “divey” turns, as objectively illustrated by a graph 800 of FIG. 8. Exemplary curves 810, 820 depict Responsiveness against Speed at two exemplary lean angles of 45 and 30 degrees, respectively. Responsiveness of truck 200 is often pragmatically described by skateboard riders as “diveyness” while executing controlled turns.
In some embodiments, approximately 15 degrees of negative rake enables the rider to execute “divey” “carvy” turns in a highly controlled manner. As the rider starts to lean on the skateboard to initiate the turn, the truck 200 will not turn very much to start. However, as the rider increases speed and/or lean, the truck 200 increases its rate of turn exponentially. In other words, the rate of turn becomes greater the more the rider leans over the board. Trucks with a pronounced negative rate provide riders with noticeable responsiveness as the rider “dive” and “lean” into a turn or curve.
While this invention has been described in terms of several embodiments, there are alterations, modifications, permutations, and substitute equivalents, which fall within the scope of this invention. Although sub-section titles have been provided to aid in the description of the invention, these titles are merely illustrative and are not intended to limit the scope of the present invention.
It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, modifications, permutations, and substitute equivalents as fall within the true spirit and scope of the present invention.

Claims

What is claimed is:

1. A skateboard truck useful in association with a skateboard platform, the truck comprising:

a base plate configured to be secured to an underside of a skateboard platform and further configured to have an underside that defines a pivot recess and a bushing seat, wherein the pivot recess houses a pivot tube;

a kingpin configured to project downwardly from the underside of the base plate, from a location spaced from the pivot recess, wherein the base plate further is configured to have a substantially vertical facing surface adjacent to the pivot recess, on the side of the pivot recess opposite the kingpin, wherein the kingpin is oriented at a predetermined angle toward the pivot recess, and wherein the kingpin and the pivot recess are configured to be aligned with a longitudinal axis of the skateboard platform; and

a hanger including a cylindrical channel configured to house at least one axle, the hanger also including a hanger pivot configured to be operatively coupled to the pivot tube housed inside the pivot recess, wherein a hanger pivot axis, a pivot tube axis and a pivot recess axis are all inline, and wherein the hanger pivot axis is substantially negatively offset relative to a pivot-to-axle axis.

2. The skateboard truck of claim 1 wherein the negative offset of the hanger pivot axis relative to a pivot-to-axle axis is between 10 and 20 degrees.

3. The skateboard truck of claim 2 wherein the negative offset of the hanger pivot axis relative to a pivot-to-axle axis is 15 degrees.

4. A highly maneuverable and controllable skateboard comprising:

a skateboard platform;

at least one wheel;

at least one axle configured to be operatively coupled to the at least one wheel; and

a pair of skateboard trucks, each truck including:

a base plate configured to be secured to an underside of the skateboard platform and further configured to have an underside that defines a pivot recess and a bushing seat, wherein the pivot recess houses a pivot tube;

a hanger including a cylindrical channel configured to house at least the one axle, the hanger also including a hanger pivot configured to be operatively coupled to the pivot tube housed inside the pivot recess, wherein a hanger pivot axis, a pivot tube axis and a pivot recess axis are all inline, and wherein the hanger pivot axis is substantially negatively offset relative to a pivot-to-axle axis.

5. The skateboard of claim 4 wherein the negative offset of the hanger pivot axis relative to a pivot-to-axle axis is between 10 and 20 degrees.

6. The skateboard of claim 5 wherein the negative offset of the hanger pivot axis relative to a pivot-to-axle axis is 15 degrees.