Patent Application
20250032890
The present disclosure relates to a skateboard truck assembly, in particular, to a truck assembly that includes a spring and elastomer bushing structure that provides an improved force profile when riding the skateboard.
Skateboards generally include two trucks mounted to the bottom of the deck that allow for the skateboard to travel over various surfaces, with the trucks providing the turning mechanism and restorative forces during turns. The trucks are the mechanisms that allow the deck to roll about its forward vector while all wheels remain in contact with the ground as the board and skater perform a turn. Traditional truck designs are many and varied, some of which rely on metal springs, while others rely on bushings predominantly made of polyurethane to provide restorative forces which provide response to the rider and ultimately return the deck to a level position. Bushing-assisted truck designs generally provide riders with a high degree of stability and control, but a limited range of motion. In contrast, spring-assisted truck designs generally provide a wide range of motion, but less stability and control when compared to bushing-assisted trucks. The type of springs used in traditional trucks include, e.g., compression springs, torsion springs, and tension springs.
The truck assembly 10 includes a kingpin 40 that passes through the opening in the kingpin cup 22, the washer 30, the spring 26, the washer 28, the opening in the cylindrical extension 32, the hanger 14, and the opening in the kingpin cup 20. The opposing end of the kingpin 40 receives a proximate wavecam 42 (e.g., a first wavecam) positioned against the outer side of the kingpin cup 20, a distal wavecam 44 (e.g., a second wavecam) engaged with the proximate wavecam 42, a cam key 46 engaged with the distal wavecam 44, and a locknut 48 for coupling the entire assembly together along the kingpin 40. In some instances, the wavecams 42, 44 can be fabricated from molybdenum nylon.
The distance 24 between the kingpin cups 20, 22 defines the maximum space in which the spring 26 can be compressed and limits the type of spring 26 that can be used. In some instances, a rider may need a stronger or more heavier duty spring to provide additional control during riding/turning of the skateboard. However, a heavier duty music wire spring may not be available or may not be compatible with the allotted distance 24. As such, the rider is limited to the maximum strength compression spring available on the market, which creates a limit to the control and/or stability provided by the truck assembly 10.
Thus, a need exists for a spring-assisted skateboard truck assembly that provides increased control and/or stability for the rider. These and other needs are addressed by the truck assembly of the present disclosure.
The present disclosure is directed to a truck assembly for a skateboard. In some embodiments, the truck assembly incorporates a bushing (e.g., a cone-shaped bushing) disposed concentrically within the spring to provide supplemental compression force during use of the skateboard. The bushing and spring are therefore compressed in parallel (or substantially in parallel) to increase the control and/or stability provided to the rider, while providing the same range of motion. In some embodiments, the truck assembly can incorporate a spring overmolded with a resilient material to provide resistance between the spring coils by filling the space between the coils with an elastomeric material, e.g., natural rubber, neoprene rubber, polyurethane rubber, or the like. Such overmolded spring provides additional control and/or stability to the rider, while providing the same range of motion, without the use of the bushing. The bushing can be used with a compression spring, and the overmolded design can be used with a compression, torsion, or tension spring. The truck assembly therefore provides improved operation of the truck assembly.
In accordance with embodiments of the present disclosure, an exemplary truck assembly for a skateboard is provided. The truck assembly includes a baseplate including a first kingpin cup and a second kingpin cup extending from a body and spaced by a distance. The truck assembly includes a hanger at least partially disposed between the first and second kingpin cups of the baseplate. The hanger includes an extension protruding therefrom, the extension including a distal end defining a surface. The truck assembly includes a spring at least partially positioned on the extension of the hanger with a first end of the spring positioned against the hanger and a second end of the spring configured to be positioned against the second kingpin cup of the baseplate. The truck assembly includes a resilient bushing concentrically disposed within the spring. The resilient bushing includes a first surface and a second surface opposing the first surface. The second surface of the resilient bushing is positioned against the surface of the distal end of the extension of the hanger and the first surface of the resilient bushing is positioned against or facing the second kingpin cup of the baseplate.
In some embodiments, the extension of the hanger can be cylindrical and the surface at the distal end of the extension can be a flat circular surface. In some embodiments, the spring can be a compression spring. In some embodiments, the resilient bushing can be a polyurethane bushing. The resilient bushing is configured to compress in parallel with the spring during movement of the hanger relative to the baseplate. The resilient bushing is configured to supplement resistance of the spring during compression of the spring from movement of the hanger relative to the baseplate.
In some embodiments, the resilient bushing can include a continuous side wall that tapers from the first surface to the second surface. The first surface and the second surface can be flat and can define a circular configuration. A diameter of the first surface can be dimensioned greater than a diameter of the second surface. The resilient bushing can define a cone-shaped configuration. The first surface of the resilient bushing can be substantially aligned with the second end of the spring.
In accordance with embodiments of the present disclosure, an exemplary truck assembly for a skateboard is provided. The truck assembly includes a baseplate including a first kingpin cup and a second kingpin cup extending from a body and spaced by a distance. The truck assembly includes a hanger at least partially disposed between the first and second kingpin cups of the baseplate. The hanger includes an extension protruding therefrom, the extension including a distal end defining a surface. The truck assembly includes a spring at least partially positioned on the extension of the hanger with a first end of the spring positioned against the hanger and a second end of the spring configured to be positioned against the second kingpin cup of the baseplate. The truck assembly includes a resilient material molded at least partially between or around coils of the spring. The resilient material is configured to supplement resistance provided by the spring during movement of the hanger relative to the baseplate.
In some embodiments, the resilient material is overmolded onto the spring to fill all spaces between the coils of the spring. In some embodiments, a surface bonding agent can be applied to at least a portion of the outer surface of the coils to assist with adhesion of the resilient material to the metal outer surface of the coils. In some embodiments, the surface bonding agent can be, e.g., CILBOND 48® available from Chemical Innovations Ltd., or the like. In some embodiments, the resilient material is overmolded onto the spring to fill all spaces between the coils of the spring and to encapsulate the coils from all sides. The spring and the resilient material combined define a substantially cylindrical configuration with a hollow interior. In some embodiments, the spring can be a compression spring, torsion spring or tension spring.
In accordance with embodiments of the present disclosure, an exemplary method of truck assembly for a skateboard is provided. The method includes positioning a spring at least partially on an extension of a hanger. The extension includes a distal end defining a surface. The method includes positioning a resilient bushing concentrically within the spring. The resilient bushing includes a first surface and a second surface opposing the first surface. The second surface of the resilient bushing is positioned against the surface of the distal end of the extension of the hanger. The method includes positioning the hanger, the spring and the resilient bushing between a first kingpin cup and a second kingpin cup extending from a body of the baseplate such that a first end of the spring is positioned against the hanger and a second end of the spring is positioned against the second kingpin cup of the baseplate, and the first surface of the resilient bushing is positioned against or faces the second kingpin cup of the baseplate.
In accordance with embodiments of the present disclosure, an exemplary truck assembly for a skateboard is provided. The truck assembly includes a baseplate and a hanger movably disposed relative to the baseplate. The truck assembly includes a dampening mechanism configured to dampen movement of the hanger relative to the baseplate. In some embodiments, the dampening mechanism can include a spring and a resilient bushing concentrically disposed within the spring. The resilient bushing is configured to compress with the spring during movement of the hanger relative to the baseplate. In some embodiments, the dampening mechanism can include a spring and a resilient material molded at least partially between or around coils of the spring. The resilient material is configured to supplement resistance provided by the spring during movement of the hanger relative to the baseplate. In some embodiments, the dampening mechanism can include both the resilient bushing and spring, and the spring and resilient material (e.g., with the same spring being used).
The baseplate can include a first kingpin cup and a second kingpin cup extending from a body and spaced by a distance, and the hanger can be at least partially disposed between the first and second kingpin cups of the baseplate. The hanger can include an extension protruding therefrom, the extension including a distal end defining a surface. The spring can be at least partially positioned on the extension of the hanger with a first end of the spring positioned against the hanger and a second end of the spring configured to be positioned against the second kingpin cup of the baseplate. The resilient bushing can include a first surface and a second surface opposing the first surface. In such embodiments, the second surface of the resilient bushing can be positioned against the surface of the distal end of the extension of the hanger and the first surface of the resilient bushing can be positioned against or facing the second kingpin cup of the baseplate. The extension of the hanger can be substantially cylindrical and the surface at the distal end of the extension can be a flat circular surface.
In embodiments using the spring and resilient bushing, the spring can be a compression spring. In embodiments using the spring and resilient material, the spring can be a compression spring, a torsion spring, or a tension spring. The resilient bushing can be a polyurethane bushing. The resilient bushing can be configured to compress in parallel with the spring during movement of the hanger relative to the baseplate. The resilient bushing can be configured to supplement resistance of the spring during compression of the spring from movement of the hanger relative to the baseplate. The resilient bushing can include a continuous side wall that tapers from the first surface to the second surface to define a cone-shaped configuration. The first surface and the second surface can be flat and can define a circular configuration. A diameter of the first surface can be dimensioned greater than a diameter of the second surface. The first surface of the resilient bushing can be substantially aligned with the second end of the spring.
The resilient material can be overmolded onto the spring to fill all spaces between the coils of the spring. The spring and the resilient material combined can define a substantially cylindrical configuration with a hollow interior. The resilient material can be overmolded onto the spring to fill all spaces between the coils of the spring and to completely surround the coils from all sides.
In accordance with embodiments of the present disclosure, an exemplary method of truck assembly operation is provided. The method includes movably positioning a hanger relative to a baseplate, and dampening movement of the hanger relative to the baseplate with a dampening mechanism. In some embodiments, the dampening mechanism can include a spring and a resilient bushing concentrically disposed within the spring. The resilient bushing is configured to compress with the spring during movement of the hanger relative to the baseplate. In some embodiments, the dampening mechanism can include a spring and a resilient material molded at least partially between or around coils of the spring. The resilient material is configured to supplement resistance provided by the spring during movement of the hanger relative to the baseplate. In some embodiments, both the spring and resilient bushing, and the spring and resilient material can be used (e.g., with the same spring being used).
If the spring and resilient bushing are used, the spring can be a compression spring. If the spring and resilient material are used, the spring can be a compression spring, a torsion spring, or a tension spring. The resilient bushing can be a polyurethane bushing.
In some embodiments, the spring can be a compression spring. In some embodiments, the resilient bushing can be a polyurethane bushing. The method includes compressing the resilient bushing and the spring in parallel during movement of the hanger relative to the baseplate. Such parallel compression results in both the resilient bushing and the spring providing combined resistance during use of the truck assembly.
Other objects and features will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.
To assist those of skill in the art in making and using the disclosed skateboard truck assembly, reference is made to the accompanying figures, wherein:
The truck assembly 100 includes a kingpin 134 that passes through the opening in the kingpin cup 112, the washer 120, the spring 116, the washer 118, the opening in the extension 122, the hanger 104, and the opening in the kingpin cup 110. The opposing end of the kingpin 134 receives a proximate wavecam 136 (e.g., a first wavecam) positioned against the outer side of the kingpin cup 110, a distal wavecam 138 (e.g., a second wavecam) engaged with the proximate wavecam 136, a cam key 140 engaged with the distal wavecam 138, and a locknut 142 for coupling the entire assembly together along the kingpin 134. Based on the supplemental compression forces provided by the truck assembly 100, additional strength for the wavecams 136, 138 may be needed. As such, in some embodiments, the wavecams 136, 138 can be fabricated from, e.g., three-dimensional printed glass bubble-filled nylon, cast short fiberglass fiber reinforced nylon, aluminum, a fiber reinforced nylon, or the like. Composite wavecams used with the truck assembly 100 can have anisotropic properties, e.g., as the melted polymer with short fibers flows into the mold, at all surfaces, the short fibers generally align with all surfaces such that the bulk of the material is more isotropic and the edges/sides are less isotropic. In such instances, the wavecams have directional properties, e.g., stronger and stiffer at the mold surface and edges, softer and more flexible in the bulk. Use of the composite wavecams in the assembly advantageously allows for carrying of higher loads by the wavecam without exceeding yield strains. By using the cone-shaped resilient elastomer bushing 144 (discussed below), higher loads are transmitted through the wavecams and resisted by the hanger 104 tabs. While testing of wavecams formed from moly resulted in deformation proximate to the hanger 104 tabs, the composite reinforced wavecams resulted in little to no deformation in the wavecam.
To supplement the compression forces provided by the spring 116, the truck assembly 100 includes a compression bushing 144 disposed concentrically relative to the spring 116. The bushing 144 can be fabricated from cast polyurethane to provide a balance between rigidity and compressibility. In some embodiments, the bushing 144 can define a substantially cylindrical configuration. In some embodiments, the bushing 144 can define a substantially cone-shaped or tapering configuration. For example,
In some embodiments, the height of the bushing 144 (as measured between top and bottom surfaces 148, 146) can be about, e.g., 5-10 mm inclusive, 5-9 mm inclusive, 5-8 mm inclusive, 5-7 mm inclusive, 5-6 mm inclusive, 6-10 mm inclusive, 7-10 mm inclusive, 8-10 mm inclusive, 9-10 mm inclusive, 6-9 mm inclusive, 7-8 mm inclusive, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or the like. The bushing 144 includes a central opening 152 extending through the entire bushing 144 from the bottom surface 146 to the top surface 148. The opening 152 defines a uniform diameter along the entire height of the bushing 144, and can have a diameter of about, e.g., 8-12 mm inclusive, 9-12 mm inclusive, 10-12 mm inclusive, 11-12 mm inclusive, 8-11 mm inclusive, 8-10 mm inclusive, 8-9 mm inclusive, 9-10 mm inclusive, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, or the like. In some embodiments, the opening 152 can be non-uniform, with a smaller diameter at the top surface 148 than at the bottom surface 146. For example, in some embodiments, the diameter of the opening 152 at the top surface 148 can be about 8.2 mm and the diameter of the opening 152 at the bottom surface 146 can be about 9.9 mm, with the inner walls of the opening 152 gradually tapering along the height of the bushing 144.
In some embodiments, the bottom surface 146 can define a diameter of about, e.g., 20-25 mm inclusive, 21-25 mm inclusive, 22-25 mm inclusive, 23-25 mm inclusive, 24-25 mm inclusive, 20-24 mm inclusive, 20-23 mm inclusive, 20-22 mm inclusive, 20-21 mm inclusive, 22-24 mm inclusive, 23-24 mm inclusive, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, or the like. In some embodiments, the top surface 148 can define a diameter of about, e.g., 18-22 mm inclusive, 19-22 mm inclusive, 20-22 mm inclusive, 21-22 mm inclusive, 18-21 mm inclusive, 18-20 mm inclusive, 18-19 mm inclusive, 19-21 mm inclusive, 19-20 mm inclusive, 20-21 mm inclusive, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, or the like. In some embodiments, the bushing 144 can be cast of a polyurethane compound having durometer 30A, 60A, 80A or 90A (Shore A); preferably 60A to 90A; preferably 70A to 90A; preferably 80A to 90A, preferably 80A. In some embodiments, the bushing 144 can be cast of a polyurethane comprising polyester or polyether soft segments (preferably polyether).
As illustrated in
The washer 120 is subsequently positioned over the bushing 144 and the top of the spring 116, and the hanger subassembly is positioned between the kingpin cups 110, 112. The kingpin 134 can be passed through the baseplate 102 and hanger subassembly, and the wavecams 136, 138, cam key 140, and locknut 142 are used to secure the entire truck assembly 100. In the assembled configuration, one end of the spring 116 abuts the base surface of the hanger 104 (indirectly through the washer 118) disposed around the extension 122, and the opposing end of the spring 116 abuts the inner surface of the kingpin cup 112 of the baseplate 102 (indirectly through the washer 120). The bushing 144 simultaneously abuts the surface 124 of the extension 122 of the hanger 104, and the opposing end abuts the inner surface of the kingpin cup 112 of the baseplate 102 (indirectly through the washer 120). Thus, both the spring 116 and the bushing 144 provide a compressible structure between the hanger 104 and the baseplate 102. The bushing 144 in combination with the spring 116 can therefore be referred to herein as a dampening mechanism.
The cone-shaped cast polyurethane bushing 144 positioned between the hanger 104 and the baseplate 102 effectively adds an elastomer (e.g., a rubber compression spring) to the metal music wire compression spring 116 in parallel. During use of the truck assembly 100, the spring 116 and the bushing 144 are compressed simultaneously, effectively in parallel (e.g., compressed substantially equally). This changes the force profile when riding the skateboard truck assembly 100 and provides optimal control for the rider. Thus, the force vs. compression curve changes from substantially lower and linear (see, e.g.,
In particular,
In each instance, by adding the bushing 144, the force profile becomes steeper and non-linear (rather than linear), indicating significantly improved restorative forces and improved control results for the truck assembly 100. By adding the bushing 144 to the assembly (or overmolded elastomer on the spring, as discussed below), the spring's linear load vs. displacement relationship is changed from “linear” to “curved upwards”. The more the spring and bushing are squeezed, the higher the realized load. The “modulus” (slope) increases as the spring and bushing combination is squeezed. In metals, this relationship is generally referred to as “strain hardening”, which is typically “permanent after the first excursion”. In the assembly discussed herein, the music wire spring and the polyurethane elastomer (also acting as a spring) provides a completely reversible strain hardening effect when the load from the combination is removed from the spring and bushing. Based on the results, it was found that positioning the 7 mm bushing in a cone down configuration would effectively double the spring constant and was most durable in the truck assembly application. However, depending on the desired spring constant, a cone up configuration can also be used.
In some embodiments, rather than a bushing 144 (or in combination with the bushing 144), the spring 116 can be replaced with an overmolded spring (e.g., partially overmolded) that includes a resilient material between the coils of the spring to change the force profile of the spring. The overmolded spring can be referred to herein as a type of dampening mechanism. In such embodiments, a surface bonding agent can be applied to at least a portion of the outer surface of the coils to assist with adhesion of the resilient material to the metal outer surface of the coils. In some embodiments, the surface bonding agent can be, e.g., CILBOND 48® available from Chemical Innovations Ltd., or the like. For example,
The process of forming the overmolded spring 200 can include formation of a mold, such as a mold 220 of
The cast polyurethane sticks to the coils 202 and provides additional resistance when compression of the spring 200 occurs. Therefore, rather than only providing resistance to compression with the spring 200 itself, the spring 200 and resilient material 204 provide a combined resistance to compression to adjust the force profile of the spring 200. The combined resistance has a similar effect to the use of the bushing 144, with a force profile substantially similar to the one shown in
Thus, rather than a substantially linear force vs. compression curve for just use of a spring (see, e.g.,
As an example,
In some embodiments, rather than only filling the area between the coils of the compression spring, the overmolded spring can include resilient material that entirely surrounds the coils from all sides. For example,
The spring 260 can be fabricated in a similar manner to the spring 200, except the openings in the mold can be dimensioned greater to accommodate the larger diameter of the resilient material 264 around the coils 262. In some embodiments, the resilient material 264 can be, e.g., polyurethane, neoprene, silicone, combinations thereof, or the like.
Although the truck assemblies discussed herein include compression springs, the partial and fully overmolded concept can be incorporated into truck assemblies having other types of springs, e.g., a tension spring, a torsion spring, an overloaded spring, or the like. In some embodiments, the tension, torsion, or overloaded spring can be incorporated into a spring-specific truck assembly, such as the truck assembly illustrated in FIG. 5 of U.S. Pat. No. 6,793,224 or the truck assembly illustrated in FIG. 1 of U.S. Pat. No. 10,335,667, each of which are incorporated herein by reference in their entirety.
For example,
As a further example,
While exemplary embodiments have been described herein, it is expressly noted that these embodiments should not be construed as limiting, but rather that additions and modifications to what is expressly described herein also are included within the scope of the invention. Moreover, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations, even if such combinations or permutations are not made express herein, without departing from the spirit and scope of the invention.
This application claims the benefit of a co-pending, commonly assigned U.S. Provisional Patent Application No. 63/516,312, which was filed on Jul. 28, 2023, the foregoing application is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63516312 | Jul 2023 | US |
