Patent Application
20200129842
This application claims priority to Chinese Patent Application No. 201811284917.3, filed on Oct. 31, 2018, which is hereby incorporated by reference in its entirety.
The present disclosure pertains to a skateboard, in particular the top component of the skateboard where the user stands.
Skateboards have become common sporting goods and have been commercially produced since the 1950's in many forms. The skateboard comprises a platform upon which the user stands, called the skateboard top, and the two assemblies affixed to the bottom surface of the skateboard top, which are called the trucks. The trucks are steering devices and also provide for affixing the wheel/bearing units.
Skateboard tops must be strong and stiff in a multitude of directions, so when the user completes the skateboard assembly with the required 2 aluminum and steel steering devices called “Trucks”, which comprise the truck device itself, plus 8 steel “bearings” and 4 rubber or polyurethane “Wheels”, and the 8 steel machine screw and nut mounting fasteners, and finally a friction enhancing Grip Tape applied to the upper major surface of the top layer of the skateboard. The user may ride the skateboard along the ground, or off of objects and land with great force. In the regular course of product usage, the user will fall from the skateboard. The board and rider parting ways, and the skateboard may continue rolling along until it stops with an impact on a hard surface such as a wall, street curb, or the hard surface of the street or sidewalk.
The oldest iteration and most common structural form for the skateboard “top”—the surface upon which the user places his feet to stand upon, and steer the direction of the board, is a platform comprising a plurality of hardwood rotary cut veneer layers adhesively bonded into a single laminate structure. Manufacturing the skateboard top is done when a plurality of wood veneer layers are bonded and formed into single structure using pressure between 2 curved mold surfaces in a hydraulic press. The bonding of the wood veneers into a single structure is facilitated through the application of an adhesive upon the inner contact surfaces of each ply, using such adhesives as polyvinyl adhesives, urea adhesives, or epoxy adhesives. The Skateboard top after lamination is a single rectangular body which may be flat or have 3-dimensional bends or curves created in the pressing process and made up of a plurality of bonded rectangular hardwood veneers. After cure of the adhesive is complete, and removal from the forming hydraulic press molds, the final shape is cut from the single rectangular structure comprising the bonded layers. The edges may be sanded to make smooth and round, mounting holes drilled through the layers to affix the two truck, a wood sealing paint is applied to the surface, and the trucks and wheels assemblies are then affixed onto the bottom surface of the skateboard top, located near to the ends of the skateboard along the major axis, to facilitate rolling and steering, thus completing the assembly of the common skateboard.
Skateboard Tops need to be strong and light to allow the user to stand upon and apply force to either side of the board in order to transfer force to the steering devices called “trucks”. The skateboard top must be light to allow the user to easily steer, control and change direction of the skateboard assembly. To achieve enough strength to allow the user to stand on the skateboard top and not break it, but also be thin and light enough in weight to control the board while turning, changing direction, or performing stunts wherein the user will kick and flip the entire skateboard into the air and try to land on it, is the engineering balance which is most desired. To control the direction of the skateboard assembly when in use, the user must apply force with pressure on the feet to one side or the other of the centerline, or major axis, of the board. To effectively and efficiently transfer this force to the skateboard trucks, the skateboard top must have sufficient torsional strength to resist twisting along its major axis and thus absorbing some of the turning force. Torsional stiffness is important to the user providing a consistent and expected amount of force transmitted through the board into the trucks which is necessary to turn and control the board.
Wood, and in particular hardwoods, may be described as an orthotropic material, it has unique and independent mechanical properties in the directions of three mutually perpendicular axes: Longitudinal, radial and tangential. The longitudinal axis is parallel to the grain of the wood; the radial axis is normal to the growth rings of the tree (perpendicular to the grain the radial direction); and the tangential axis is perpendicular to the grain but tangent to the tree's growth rings (
A skateboard top “shape” which has been cut from this pressed and bonded multi ply wood grain oriented veneer structure, exhibits stiffness and strength longitudinally parallel to the major axis, and stiffness and strength perpendicular to the major axis, and stiffness and strength in torsion in a twisting direction along the major axis.
Skateboard top construction using a plurality of hardwood veneers is known in the art. This construction technique began in the United States of America in 1970's. Little has changed in the design from inception to present day. From inception to present day, variants of the laminated hardwood concept have been used, including but not limited to more and thinner plies of hardwood veneers, and improvements in adhesives which created stronger boards and more durable bonds between the veneer plies.
A common design known in the art is to use 7 plies of a hardwood veneer, and utilize a balanced veneer orientation described as:
While a multitude of common skateboard tops use this 7 ply bi axially oriented construction, there are other constructions utilizing more plies and those plies can also be orientated in either parallel or perpendicular to the major axis. It is not uncommon to see skateboard tops made using 8 plies, 9 plies, 10 plies. Each of these examples will have a unique and particular set of layers oriented in either a parallel or perpendicular direction, yet all will exhibit a balance of veneer layer orientations which are mirrored about the Neutral Axis center ply.
The compressive strength, and resistance to flex in wood, and in particular the veneers used to make up a skateboard, is greater in the direction parallel to grain than it is perpendicular to grain. The strength of a veneer in resistance to tensile force is also greater in the direction parallel to the grain then it is perpendicular to the grain. The strength of a veneer in resistance to compression force is also greater in the direction parallel to the grain then it is perpendicular to the grain. Also, the strength of a veneer in resistance to shearing force is greater in the direction parallel to the grain then it is perpendicular to the grain.
When veneer is in the described orientation with layers 1, 2, 4, 6 and 7 with grain parallel to the major axis of the skateboard top and layers 3 and 5 with grain perpendicular to the major axis, layers 3 and 5 are subjected to more compressive or tensile forces perpendicular to their grain direction during common use and impacts with the ground and or other objects at the ends of the skateboard top where the impacts may occur most. Layers 3 and 5 are oriented in such a direction as to make them weaker in tensile and compressive forces under impact stress then the adjacent plies which have orientation of grain parallel to the major axis of the board. This is the problem in which the disclosure teaches to solve.
Tensile forces acting simultaneously on all 7 layers of the structure can be described as flexing, and also abrasive wear when the bottom layers at the end of the skateboard's major axis come into contact with the ground.
Compressive forces acting simultaneously on all 7 layers of the structure can be described as the impact of the ends of the skateboard against solid objects, for example a wall, a curb or the ground itself. These forces are commonplace to the use of the skateboard, as the user will ride the skateboard and occasionally jump off or fall off while riding or performing stunts or tricks. The impact areas are at the ends of the major axis, commonly known as the ends of the skateboard top. Impact forces are derived from the contact of the edges of the skateboard top with solid objects. These impacts impart a compressive force to the edge of the laminated skateboard top structure. As noted by the compressive strength characteristics of wood veneers in parallel to or perpendicular to the wood grain orientation, 5 of the plies which are parallel to the impact force direction resist compression and dissipate the force along the longitudinal direction of the grain. 2 of the plies of the wood veneer which are oriented with the longitudinal grain direction perpendicular to the impact force will crush, compress, and break. Upon compression and breaking from repeated impacts, the 5 plies of the wood veneer which are oriented parallel to the impact force can become separated from the 2 plies oriented perpendicular to the impact force, the interface bond between the #2 and #3 and #4 plies, and or the #4 and #5 and #6 plies may be broken, and some layers may break off the skateboard top structure, leaving the skateboard top badly damaged and un-usable.
The #3 and #5 plies in a common 7 ply skateboard top are subject to early failure through the compressive forces inherent in the use of the product through falls and the resulting impacts.
The disclosure differs from other fiber reinforcement skateboards described in patents such as Gallo (U.S. Pat. No. 7,735,844 B2). In Gallo, Thin fibers are bonded to the surfaces of the plies and not direct replacement or substitution of the wood ply in its entirety. In Gallo, wood veneers with grain direction orientated perpendicular to the major axis of the skateboard are still exposed to impacts and exposed to the compressive forces which cause these veneers to break. Bonding a reinforcement to the top and bottom major surfaces of the veneers still leave the veneer itself exposed to forces.
This new skateboard top disclosure is unique by not bonding reinforcement to the major surfaces of the veneers but to replace the veneer completely. Gallo does not do this, and as such the impacts on the edges of the Gallo skateboard still allow the veneers to compress, and chip.
According to one aspect of the disclosure, a skateboard top comprising a plurality of layers of hardwood veneer layers is provided.
The skateboard top as above, wherein the layers have a natural wood grain orientation running either parallel or perpendicular to the major axis of the skateboard top.
The skateboard top as above, wherein 5 of the layers have grain orientation running parallel to the major axis and 2 of the layers have grain orientation running perpendicular to the major axis of the skateboard top.
The skateboard top as above, wherein the 2 layers with grain running perpendicular to the major axis of the skateboard top have been modified with an omni directional strength material placed at both ends of the major axis of the skateboard top.
The skateboard top as above, wherein the omni directional strength material is comprised of a non-wood material.
The skateboard top as above, wherein the omni directional strength material may be a stitched or woven layer of fibers saturated with an adhesive.
The skateboard top as above, wherein the adhesive may be comprised of a thermoset epoxy.
The skateboard top as above, wherein the adhesive may be comprised of a thermoset polyurethane.
The skateboard top as above, wherein the omni directional strength material may be comprised of fiberglass.
The skateboard top as above, wherein the omni directional strength material may be comprised of nylons, aramids or polyester engineering thermoplastics.
The skateboard top as above, wherein the omni directional strength material may be comprised of a solid engineering thermoplastic sheet.
The skateboard top as above, wherein the omni directional strength material is equal in thickness dimension to the adjacent veneer.
The skateboard top as above, wherein the adhesive may be comprised of a thermoset epoxy.
The skateboard top as above, wherein the adhesive may be comprised of a thermoset polyurethane.
According to another aspect of the disclosure, a skateboard comprising the skateboard top as above is provided.
1
a is the upper surface of the skateboard top, where the user places his or her feed to stand and control the direction of the skateboard.
1
b: indicates with a dotted line the major axis of the skateboard top. 1c: indicates with a dotted line the minor axis of the skateboard top.
2
a: indicates the mounting nuts and bolts for affixing the trucks and wheels to the bottom major surface of the skateboard top.
In illustration of the terminology used in the preferred embodiments of the disclosure,
Referring to the figures of the embodiment now,
The preferred embodiment of this disclosure of a skateboard top with integral anti-chipping/anti-delamination reinforcement layers comprising non grain omni-directional strength materials has three dimensional curved surfaces pressed into the skateboard top as
The disclosure can be illustrated best by separating each individual component layers shown in
Now that we have described 2 of the 7 layers comprising the disclosure of the skateboard top,
The layers are affixed and bonded into a 3 dimensional shape shown in exploded side view of
After the individual wood layers are bonded together using adhesives and press molded to shape into a single structure as shown in
A close-up view is helpful to see the detailed layering of all the veneers, including the veneers of the disclosure which include the integral anti-chipping/anti-delamination reinforcement layers comprising non grain omni-directional strength material.
The disclosure teaches to replace sections of the #3 and #5 wood veneer plies in said common 7 ply skateboard top with a non-grain, omni directional strength material, and in particular replacement in the portions of the 7 ply skateboard top directly adjacent to the impact areas at the ends of the major axis.
Replacement of the ends of the #3 and #5 wood layers with the omni-directional strength material is performed before the layers are laminated together. Wood layers #3 and #5 are modified to make shorter than the adjacent plies, and pieces of the omni directional strength material are set in place as the individual veneers have the adhesive applied and the stack of 7 total plies is assembled prior to placement in the hydraulic forming press.
The problem of other skateboard constructions can be solved through the use of this disclosure. The problem of failure via chipping or delamination of wood layers through impacts can be reduced or eliminated, with the substitution of the omni directional strength material where the weaker #3 and #5 wood layers are subject to compressive impact forces at the ends of the skateboard top along the major axis. Because the strength of the omni-directional strength material is greater in compression than wood veneer, substitution of omni directional strength material in place of the wood veneer increases the durability, impact strength and lifespan of the skateboard top structure.
The preferred non grain, omni directional strength material can be, but not limited to, a single layer or multitude of layers of bi axial, tri axial or quad axial fiberglass cloth or weave, which is saturated with a resin matrix acting as an adhesive between the fiberglass fibers to themselves, and between the fiberglass layer and the adjacent major surfaces of the wood veneers. Other non-grain, omni directional strength materials can be a solid engineering thermoplastic sheet, or, woven or stitched layers of fabrics using non glass fibers such as nylons, aramids or polyester blends. The thickness dimension of the omni directional strength material must be the same as the wood layer material it replaces.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201811284917.3 | Oct 2018 | CN | national |
