Patent Application
20090165697
Many small watercraft have an enclosed or a semi-enclosed hull of composite construction consisting of an outer structural shell combined with an inner cavity, or a lightweight core material. Examples of such hulls include, but are not necessarily limited to, surfboards, wave skis, paddleboards, windsurf boards, and kayaks. The shape and size of the hull is usually determined by hydrodynamic and ergonomic considerations such as the desired buoyancy, planing area, and the planform. The details of the construction of the hull and shell, and the choice of core material(s) are substantially driven by structural, durability, and weight considerations. In general, the choice of design and type of construction represents a compromise among these competing considerations.
In recent years, a substantial interest has developed in the flexural properties (e.g. deflection magnitudes, temporal and spatial spectral characteristics, and dampening of vibrations) of such watercraft as a means of improving the performance and “feel” of the craft-especially in executing maneuvers. These additional considerations make optimizing the design and the construction of the craft substantially more difficult to achieve using current design and construction methods.
This invention discloses a system that facilitates “tuning” the flexural properties of such a watercraft through the addition of one or more semi-independent structural subsystems incorporated into the design and construction of the board. Each subsystem can be viewed as a structural network comprised of “linkages” and “nodes’. The linkages in this network are structural elements such as tubes, rods, beams, etc. These may be straight, or curved, but typically have one elongated axis. The design, and materials used in a linkage are selected to produce their desired flexural properties. The nodes are simply the junctions of a linkage with another linkage or linkages, or one or more linkages with the hull. For convenience in design purposes, it may sometimes be convenient to consider a subsystem as comprising of a grouping of subassemblies.
The nodes may consist of rigid couplings, hinged (“pinned”) joints, or sockets permitting restricted rotations of the linkages (generally along their elongated axis). In some cases, the coupling may be spatially extended along the axis of a linkage (e.g. an extended connection between the node/junction and the shell of the hull). The end result is a skeletal framework enclosed within the hull, or exterior to the hull, or a combination of the two-depending on the type of hull and/or the desired flexural characteristics. Optionally all nodes and linkages may be located in, on, and through the watercraft or combination thereof.
This structure allows one to modify the flexural characteristics of the hull. Consider, for example, the hull of a surfboard would normally be subject to high loadings at the location of the rider's feet on the board. The latter are located near the center of lift of the wetted portion of a planing hull. When this loading is increased (e.g. when the surfer stands on the board, or when executing a turn) the primary deflection of the hull will be a bending downward of the portion of the hull under the feet, relative to the forward and aft ends of the wetted area of the hull. This will increase the effective rocker of the hull. However, if the suspension subsystem comprises a longitudinal beam attached at each end (i.e. a nodal point) to the bottom shell of the hull, and to the upper shell of the hull at the location of the rider's feet, any increased loading will tend to deflect the portion of the hull in the area of the rider's feet upward, relative to the bottom at the attachment points of the beam to the hull (i.e. the opposite effect of the hull with no linkage system). In general, an actual system would have a more complex suspension system involving not only these types of gross hull deflections, but also to control the response of fins attached to the hull to changes in both loading magnitudes and locations. This is especially true for fins which have cant (or splay).
In general, the overall flexural response of the hull (and fins) in a system with suspension will depend on the combined characteristics and coupled interactions of the hull, the suspension subassembly, and the points of contact between the hull and the suspension subassembly. Hence the subassembly, with its nodes and linkages acts as a network in which a change anywhere in the system produces changes throughout the network and the hull.
So far, only the flexural deflections have been discussed. However, the temporal characteristics of the flexing can also be important. For example, a common maneuver executed by skilled surfers is to “pump” the board across the face of the wave to increase his speed (“pumping” has similarities to the alternating leg strokes of a speed skater for propulsion). The surfboard will flex as the rider alternately applies and relaxes foot pressure on the deck of the board. When he presses down, a deflection of the bottom of the board will occur. If this produces increased rocker, executing the turn may be facilitated; if decreased rocker is produced, execution of the turn will be inhibited. Rocker deflections will be accomplished with minimum effort if dampening of the hull deflections is minimal, and the frequency of the loadings generated by the surfer when pumping matches the natural frequency of the rocker deflections—i.e. when the hull is resonant with the surfer's efforts. This is analogous to a rider on a pogo stick. However, in this case of minimum dampening, it may be easy for the board response to develop large deflections and the loss of control for the rider. The challenge for the board builder is to match the flexural response and dampening to the needs of the rider—and the desired characteristics may change from rider to rider. Similar situations can arise when surfing through chop on the surface of the water (i.e. oscillatory loadings imposed by the wavelets striking the hull of the board).
The response characteristics of the suspension system may be (and generally will be) substantially different from those of the hull and are related to the geometry of the linkages in the suspension system and the flexural properties of the linkages, including the magnitude of deflections (linear and/or torsional) when subject to loadings (and/or torques), the natural modes and frequencies of vibration, and the dampening of the vibrations. These qualities can be altered by changes in the shapes and dimensions of the linkages, and by the materials incorporated into the linkages (which, if appropriate, may be of composite construction).
A subassembly may be comprised of a set of nod points connected between the set or subsets by elements with flexural and or torsional properties that can be chosen to customize the flex response of the watercraft and resultant watercraft comprising a subassembly or subassemblies structurally engineered and manufactured to be fitted optionally in, on, and or through, or combinations thereof to a aquatic watercraft. A subassembly may be mounted in various manners to the watercraft and optionally connect to the fins or fin attachment systems of the watercraft or surfboard. A subassembly may be of composites in the form of hollow structures, partial hollow cavity, cored with other materials or of foam filled tube or tubes and plates structures mounted on in and through a surfboard. The surfboard may be of hollow, cavity, or of a foam core, or other various constructions. A subassembly mounting or receiving geometry detail may be manually shaped, machined shaped, molded or combinations thereof into the core or a mold. The invention relates to methods for making and producing completed watercraft and cores incorporating the subassembly or subassemblies or prepared for incorporating a composite subassembly or subassemblies and surfacing the craft with combinations of various skins and curable resins and structural fibers such as fiberglass or carbon, and/or thermosetting plastics either manually or in molding methods.
An objective of this invention is to incorporate one or more subassemblies into the construction of a surfboard which will provide the surfboard designer and builder more degrees of freedom in the design and construction so as to assist him in manufacturing a board that can better match the board characteristics with the rider's preferences in relation to the wave conditions. The controlled flexural properties of this invention include not only the degree of flex as a function of loading, but also the temporal response of the flexed system to intermittent loading and unloading by the surfer and the hydrodynamic pressures on the surface of the board. For example, flexural response can be expected to be most rapid and require the least effort when the frequency of loading and unloading by the rider matches the natural frequency of that mode of vibration of the board (i.e. the loading and response are in, or close to, resonance). Flexural motions affect not only the “feel” of the board, but also its hydrodynamic performance and, in some instances, the structural strength (e.g. structural failure due to buckling). Controlled flexural movements can also provide new hydrodynamic means of controlling the board and increasing its performance, such as the addition of hydrofoils.
Among the combinations embodied in this invention are the subassemblies themselves and their attachment alternatives. Alternatives of the subassemblies include the external affixing of the exo-skeletal structure to the receiving points on the board and optionally attaching it at the point of sale of the watercraft. This external configuration provides the rider with the specific ongoing changeable choices of alternative flex degrees to that of the basic board. The overall movements and speeds achieved through the changing out of different flex control parts that may be externally and internally mounted or in combinations thereof are significant. These alternatives also offers variable aesthetics available and optionally at the time of sale in the store.
The predominant method for manufacturing surfboards is using molded polyurethane foam blanks. The foam blank is generally molded and then structurally reinforced with a wood stringer that is glued into the foam along the centerline of the blank. This wood stringer is installed for a number of reasons that include structural reinforcement and rocker or longitudinal curvature correction. The foam blank is molded to the approximate size required for the finish or custom shape dimensional requirements. The remaining removal and shaping and sanding are then completed by either a computer controlled shaping machine and/or by a person. An outside covering lamination of a curable resin combined with fiberglass is then applied, sanded, and reapplied to produce a structurally sound and exterior visually acceptable product.
Among the structural subassemblies and their combinations embodied in this invention are alternatives of the subassemblies. Alternatives can include the internal and or external or combinations there off for the placement and affixing of the exo-skeletal structure or structures in the rail (or edge) of the surfboard and other areas of the watercraft. In one example the carbon structures including tubes may be used in combination one on top of the other to form a oval shape thereby maximizing the structural flex and recovery properties of the joined tubes when positioned in the rails or central areas between. The rail subassemblies such as carbon rods may be encased inside, outside or combinations thereof in a foam or alternative box like structure and may incorporate end securing and adjusting means for the purpose of assembly or installation into the surfboard as complete subassembly unit or units. This subassembly box or multiple box like unit or units containing the non-stressed or pre-stressed carbon rods provides for the optional completed exo-skeletal structure to be installed into the surfboard at any stage of the construction phase to aid in the simplicity of installing multiple parts and potential complicated and dynamically loaded parts. The rod box like subassembly maybe pre-assembled in completed units for installation prior to the completion of the watercraft. These encasing units may provide for the carbon tube to be used in both a internal and external form in the box like unit could be below the deck surface of the board and then emerge from the deck surface of the board. The rod box like subassembly would then be fared into the general deck contours while still retaining the exposed contours of the box and encased tube unit (a bump on the boards deck). In combination with the aforementioned transitioning unit or units the carbon tube could transition from inside box unit to become exposed through and on the boards deck. The purpose for this would be to create a diagonal extending ramp or foot kick pad like structure for the rider to leverage with his foot or feet (in the case of forward and rear positioned ramp devices) in maneuvers. Optionally these ramp devices may be combined with one or more curved composite tube or tubes to form a completed multi-curved pre-stressed flex structure. The multi-curved, S curved or compounded curved tube may optionally be housed inside and outside the board and inside and outside the box unit or units in combination with inside and outside the board. The externalized tube like structures may be used in association with a soft and or hard pad or pads. The pads may incorporate the tubes in, on and or around the extruding tube like structures. This flex ramped kick pad provides the rider with both the flex force control opportunity of pushing down on a tube extending diagonally up and out (to form the ramped flex kick pad) with his back and optionally front foot thereby using the tube resistance provided by the exposed tube or tubes and optionally his front foot pressing down on the crowned up forward or front tube or tubes for the added spring of the completed system. This back foot system may be used independently or in combination with other flex means.
The present discloses a flex and resonance controlled subassembly and related watercraft and specifically for a surfboard. The subassemblies described in this invention disclose a system that facilitates “tuning” the flexural properties of such a watercraft through the addition of one or more semi-independent structural subsystems incorporated into the design and construction of the board as shown in the following description:
The invention relates to the fabrication of a wave riding or paddled aquatic board, and particularly to the use of one or more structural subassemblies incorporated into and onto a surfboard. The method additionally relates to a method for the manufacture of these subassemblies and to a board manufactured using the subassemblies.
Most surfboards presently consist of a foam core that is shaped to produce the desired final shape of the board. Furthermore, most (but not all) traditional surfboards have one or more stringers mounted in various areas of the board. The latter typically consist of a vertically oriented strip of wood that runs along the centerline of the longitudinal axis of the board and is exposed on the top and bottom faces of the shaped blank. Stringers may also be mounted off center or edge or rail mounted in the surfboard. Other materials, such as dense PVC foam, Sphere-Tex®, micro spheres, and various types of honeycomb are sometimes used in place of wood as stringers. The stringer stiffens up the board and the resulting increase in rigidity assists in the shaping of the board, as well as contributing to the stiffness and strength of the completed board. Some surfboards are molded in various ways with varying use of stringers and horizontal and longitudinal reinforcing elements.
The force of gravity is constantly acting on a surfer and his board when riding on a wave. The slope of the wave face along the surfer's path across the face of a wave, combined with the angle-of-attack (AOA) the bottom of the board makes relative to the surface of the water, determines the magnitude and direction of the lift and drag forces on the board. The overall board deflections and movements as well as the speed of these movements play an important role in the speed and performance capabilities of the craft when combined with the mass of the surfer and board, their centers-of-mass, and moments-of-inertia when riding on the face of a wave. In general during the course of riding a wave, the surfer's speed and direction of motion will change, resulting in a change in the vertical location of the board on the face of the wave, as well as its proximity to the breaking portion of the wave, as the surfer exchanges potential energy for kinetic energy, and vice-versa. At the same time, the slope and curvature of the wave face along the board's path also varies. These performance requirements of the board in the shape and structural flex of the surfboard to optimize performance.
This invention controls flex movements, and the speed and variations in the boards overall movements through the use of engineered composite subassembly parts and their connections and placement. This flex movement control coupled with the optional fin connection feature provides greater board speeds and performance by engineering the degree of flex, speed of the flexural response and the details of the combined subassembly and board.
By way of an example, consider a fully planing boat hull consisting of a planar surface that is bent into a surface with rocker in the fore-and-aft direction, and in which the center-of-mass can be trimmed forward or aft to minimize the total drag of the craft. A first approximation to an optimal rocker can be obtained by noting that planing surfaces achieve their lift by the downward deflection of water (generation of downward momentum) passing under the hull. In the case of the boat-planing hull, no lift is generated when the AOA is zero, since the free stream motion is parallel to the hull and no deflection occurs. The analogous case for the surfboard is if the curvature (rocker) on the bottom of the board is parallel to the curvature of the wave face over the wetted length of the board. In this case, for an AOA of zero, there is no “downward” deflection of water. Thus, by analogy to the case of flat water—and to a first approximation—one might expect that the best performance (in terms of maximum speed) for a surfboard on the face of a wave would be with this “natural” rocker. But this curvature changes during the ride as the rider's speed, path, and position on the face of the wave change. Hence unless the surfboard rocker can be altered to conform to these changes, the rocker built into the board as it is constructed will only be optimal (from the standpoint of minimum drag and maximum performance) for a single location on the face of a wave.
A flex control capability is achieved in this invention via the variable flex speeds and flex movement controls built into both the subassembly or exo-skeletal composite structure and the board. In one example of these features the “spring” (or degree of flex and flexural speed) is achieved in the composite subassembly and the board follows via the attachments connecting the two. The board follows the subassembly's movement and speed in the region of the attachment points, and optionally can be built with optimized skin strengths for specific movements outside of the immediate subassembly areas. The degree and speed of these board movements can be greater or lesser that those of the subassembly. This combination of materials properties and performance gives a multitude of options to the overall designing of the board's geometry such as bottom and or rail or edge rocker. Another example of these options is with the subassembly attached in the rear through the board to the fins and at the front or nose end. A fixed or moveable bridge may be installed between these two attachment points approximately midway in the length of the tubes. There are a number of means to create a curved tube or tubes which in turn pre-stresses the subassembly and the board. A fixed or movable bridge may be used. The bridge or bridges and resultant stresses can change and or adjust the overall rocker or curve of the board. Various wood elements may be used in conjunction with the suspension exo-skeletal structure
In an additional optional feature of this invention an edge or rail mounted structural flex control composite reinforcement may be installed inside or outside as both a flex controlling means board top and bottom connecting or closure feature. In the case of a solid or cavity cored board construction, a carbon unidirectional or optimally oriented filament or fiber woven or non-woven composite may be incorporated into the rail makeup adding in effect and I beam optional features individually or in combination peripherally contributing to the increasing the various rail area strengths. The rail construction options may also include using a composite tube structure placed either on the outside or inside on the rail to achieve some, or all, of the features stated above. Additionally a prefabricated partial or half tube structure may be used in the deck of a board to create the exact receiving geometry necessary for coupling with a complete tube-like structure when engaged from above in the installation process into the board.
In the case of a hollow or cavity board construction, a carbon unidirectional or optimally oriented filament or fiber woven or non-woven composite may be incorporated into the rail makeup adding the optional features individually or in combination peripherally contributing to the increasing of flex movements speeds, of stress point mitigations, of increasing the various rail area strengths and of optionally being used to achieve rail closure or the joining of the top and bottom halves of the board during final assembly. The rail construction options may also include using a composite tube structure placed either on the outside or inside on the rail to achieve some or all of the features stated above.
The pre-stressing of the subassemblies as a whole or as function of separate parts of the subassembly gives additional options to overall flex properties of the board in all its various construction options. These options create advantaged conditions for the both the pre-loading of the subassembly and the board under specific design parameters.
In an alternative embodiment of the invention composite three-dimensional structures may be fixed to the inside of the rail. The composite rail reinforcement adds additional flex control to the complete boards flex capabilities. This composite three-dimensional structure may be fixed to the inside of the rail and be a pre-constructed tube in round, square, rectangular, or other shapes of varying lengths. Alternatively, composite three-dimensional structure or structures may be fixed to the inside on the rail. These structural flex elements may be constructed with hollow or foam filled cores and may have external reinforcements added during the installation process with woven or non-woven webs or cloths. In an alternative embodiment of the invention a composite three-dimensional structure or structures may be fixed to the inside of the rail. This composite three-dimensional structure or structures may be fixed to the inside of the rail and be a pre-constructed tube in round, square, r rectangular, or other shapes of varying lengths. This composite three-dimensional structure or structures may be fixed to the inside on the rail.
These exo-skeletal composite structures may be placed in various weight foams or alternate materials to reinforce the placement and alter the movement of the structures and alternatively to aid in the assembly of component parts.
In an alternative embodiment of the invention a composite three-dimensional structure may be fixed to some portion of the board and foams of different weights may be incorporated into the forward area of the board while maintaining heavier outer rail foam strips to reduce the “swing weight” (moment of inertia) of the front of the board during turn movements.
In an alternative embodiment of the invention a composite three-dimensional structure may be fixed to some portion of the board and various weight foams may be incorporated into various areas of the board while maintaining the structural integrity of the board through the use of the exo-skeletal structure to achieve the flex control. This de-building or deconstruction or the general reduction of materials and the possible weight reduction of the traditional board materials and weight and speed movement options of this invention provides more opportunity for the exo-skeletal installation methods and structure or structures of this invention to dominate the flexural movements and speeds of the overall board's structure and dominates flex structural element responds and controls the movement and degrees and or speeds of the watercrafts overall flex and flex degrees or distances and speed movements The deconstruction of the traditional materials opens the physical options for movement of the exo-skeletal alternative physical structure and therefore the movements their combined performance movements to emerge as the first and or primary and dominant contribution to the overall movements of the flexural aspects of the rider and the watercraft.
In all of the many assemblies and various constructions of this inventions described watercraft the various composites including unidirectional and traditional fiberglass materials described as well as thermoplastic composite fiber structures material assembly alternatives such as resin transfer molding techniques defined and available to this invention This inventions manufacturing alternatives may be used to integrate the attachment and structural construction affixing alternatives listed and anticipated herein and the overall exo-skeletal constructs of the described inventions defined herein of the this inventions exo-skeletal structure. All attachments from both above and below and all affixing methods of the exo-skeletal structures described and any described manufacturing methods comprising any and all the of the alternatives discussed in this invention for the outer and any skin and covering materials constructions discussed in this invention and the any and all of the over all manufacturing methods described in this invention that are included as elements of this invention. The watercraft may also incorporate inner (inside the rail construction) and outer (outside the rail construction) composite structures or combined combinations using alternate materials such as, but not limited to, wood. These rail mounted composite flex control performance enhancing elements may be mounted in such a way to connect to, or not to, exo-skeletal structures The rail mounted flex elements may be connected to and incorporated into the central flex subassembly or subassemblies. Another example of the invention's options is that the subassembly may be attached in the rear to and or through the board and to the fin box receiving or additional attaching sub-assemblies. The subassemblies frontal area or nose and rear end may be attached to the board by multiple means, which may include on, in, or in combinations, including through the board. This invention anticipates one or more of the attachment points approximately at the end of the lengths of the tube or tubelike structures. These attachment points may be affixed to and or elevated onto a bridge or structural support element. And spacing means may be installed between the subassembly and the board. This elevated connection creates a raised connection point and allow for the part or parts which may incorporate pre-stressed tubes or tube-like structures, which in turn pre-stresses the board. The board and the pre-stressed subassembly may then push against one another and with varying reinforcements on either the subassembly and or the board thereby controlling the degree of the individual pre-stressing of the parts.The resultant stresses can change and or be adjusted to the overall desired rocker or curve of the board. The finished board rocker may have been engineered to be the initial rocker prior to the installation of the pre-stress subassembly or subassemblies. This could achieve the correct finished rocker or the board's initial rocker and can remain unchanged with the installation on the subassembly. Alternatively the initial board rocker may be built relatively flat and the subassembly may push or pull the needed rocker curve into the board. The subassembly or subassemblies can provide the main or dominant flex and rocker curve control features to the board under the waves and riders dynamic conditions. Additionally the subassemblies front and or rear end areas may be elevated from direct connect with the board thru the use of spacers or other means and thereby pre-stress and alter the board's rocker. This rocker control may be altered with the addition of complete or partial structural elements in the board's bottom, top deck, thru the centerline or off-centerline locations of the board.
A surfboard with rocker on the bottom will also generally turn with less effort than an identical board with less rocker. Since most experienced surfers like to maneuver on the face of a wave, a surfboard designer is faced with deciding how much rocker to put into the bottom to achieve the best compromise between speed and maneuverability.
This invention engineers and offers the rider the choices and controls of the loaded or rail turn extended rocker movements including degree and speed of the board's rocker and twist movements. The subassembly, when connected to the fins and or the fin receiving devices can also control the fins movements including degree and speed of the twisting and splaying in the fin movements. The invention's options of the various subassemblies the various board shapes and constructions and the various fin or board rail constructions may be varied and or combined to achieve the desired performance enhancing features of flex control, board speeds and turning attributes.
This invention optionally offers the rider the choices and controls of the movements including degree and speed of the board's bottom contours and flex movements concave or double concave shapes in the direction of the water flow. This can be achieved with the incorporation of a cavity or hollow spaces being created between the outer skin of the bottom of the board and the inner core thereby allowing the outer skin to flex inward with the force of the water flow pressure. By placing a dividing in the center of the cavity two areas of concave bottom contour are created on the bottom of the board.
As discussed above, an alternitive solution is to design and construct a board such that it distorts its shape under various types of loading to help the board conform to “optimal” maneuvering shapes as maneuvers are executed on the face of a wave. A number of such “adaptive” wave-riding vehicles have been designed and built in the past. In some of these boards the flexibility required to provide the desired “adaptability” is a consequence of changes in the shape of the structure of the craft, in the materials used in the composite construction, and in the laminating schedule. Thus once constructed, they perform best for a person around the weight of the “design surfer” and with a specific riding style.
In another design Tinkler design (U.S. Pat. No. 3,988,794), increased flexibility is provided thru the use of a set of “fingers” and springs that can be adjusted for stiffness, preload, etc. B this approach achieves this capability at the expense of introducing more complexity, cost, and weight.
There are two main elements to consider when looking at the physics behind a Mechanical Potential Energy Storage Structure or “MPESS” (e.g. a pre-stressed compound curved frame) in and on a surfboard. First there is the MPESS or frame itself. This is a structural device that uses by way of storage the imposed forces introduced by the rider's weight and movements. The device converts the resulting deflection into stored mechanical potential energy (“MPE”). The frame may be configured in a variety of forms such as a compound curved structure or a recurve structure. The compounding of the curve can be achieved through physically curving the structure and or building up the composite wall structures in a compound fashion and should additionally have bridge or beam span adjustment devices used in association with the frame. The second factor involves converting that stored mechanical energy back into kinetic energy when the rider releases it through his various physical motions. In the process almost all of that kinetic energy is transferred or released to the surfboard and its resultant movements.
When riding on a wave the MPESS is continually adjusting the overall board curvature (rocker) and speed of flex movements due to the changing loading. The driving mechanical alterations come from rider's force inputs into deflections of the frame with the board following these changes. This is particularly the case when the structural features of the board and MPESS are integrated and optimized to yield the desired degree and speed of the flexural movements. This is achieved with the redirecting of the structural elements such as the core materials and the skin materials being reduced in one area and increased in another requiring the structural optimization process.
Tinkler Patents:
U.S. Pat. No. 3,988,794—Surfboard with resilient tail
U.S. Pat. No. 4,649,847—Hull construction
U.S. Pat. No. 5,425,321—Sailboard and the like
In one embodiment of the invention the composite frame structure passes through the surfboard and emerges at the rear of the board with the fin structures attached. This joining of the composite frame with the fins provides for the forces of the frame and fins to be more directly felt and controlled by the rider. Another way to look at the Mechanical Potential Energy frame is in respect to a spring. The composite frame structure is analogous to a spring that is storing energy that can be transferred into the board's movement once the rider loads and then releases it. To realize the amount of force that is applied from the composite structure we must look at a number of ideas and concepts. For this application we will use only a recurve or end curved bow or a reflex shape, which basically is a long piece of composite tube with two ends that are “recurved” away from the riders contact points (feet). The various optional configurations or tube structure originations are many in relation to their use for board or variable rider's movements. Then those points are simply pushed down away from the rider's weight by using his feet. As the rider un-weights his feet on the frame the attached board moves with the degree and speed of the composite frame in combinations with any other associated contacting materials. There are also a number of other structure shape concepts that can be used. For instance, the compound curve frame, the S curve structure, the reverse S curve, the protruding or diagonally extending tube like structures(extending outside the boards deck surface) both in association with and without the various tube curved and non-curved structures. The compound curve frame can be made or adapted to be similar in design except to that of the optional flex structures disclosed in this invention. The compound curve uses different mechanical properties to produce a greater amount of stored energy with a less amount of human force required. The composite materials and their makeup that construct the recurve or compound curve shaped frame must be taken into consideration when looking at the forces both applied and produced. The most useful natural material that could be used would be a certain type of wood from the yew tree. The reason for this particular choice of wood is that it contains the highest elastic energy storage per unit mass for any type of wood, which is around 700 Jkg-1. This is very close to having the same rating as spring steel. However in the preferred form of the invention a composite technology using carbon or a carbon-fiberglass laminate construction will be used. This particular combination brings both a lighter weight than wood and a higher elasticity rating
In related U.S. Pat. No. 6,736,689 a structural subassembly is provided to produce an aquatic gliding board. The subassembly includes a hollow inner shell which is covered with a casing made of foam capable of being machined. The invention also relates to a method of making such a subassembly and to a board made by covering the preceding subassembly with a layer of resin-coated fibers.
There have been a number of efforts at changing the base foam blank for the surfboard industry. The current invention provides the option for the use of engineered composite structures and through their use achieving reproducible flex and strength properties
There are a number of alternative or modified methods of surfboard construction. For example, the foam core may be skinned with some intermediate material, such as a denser foam, before glassing to increase the compressive strength. Alternatively, composite sandwich skins may be molded for the upper and lower portions of the board, and then joined at their perimeter. In another alternative, a mold and an inflatable bladder may be used in combination with composite sandwich construction methods to form the complete board in a single step. These latter two methods result in a hollow board.
The construction method, the type of materials used, and the specific design details (e.g. type, weight, and weave of fibrous reinforcing material, type of resin, type and density of foam, stringer width and composition, etc.), when combined with the physical dimensions of the board, determine its weight, flexural properties, and strength in the presence of various types of loadings.
The experienced surfer develops preferences for certain characteristics in his boards. In general, these preferences will be related to his skill level, his physical characteristics, and the type and size waves he wishes to surf with the board. The hydrodynamic design of the board is one variable affecting these characteristics, other variables include the weight of the board, its moment of inertia (particularly about the yaw axis), the flexural characteristics of the board, and its durability. In general, a change in any one of these properties (e.g. due to dimensional changes, compositional changes, or construction method) will simultaneously change many of the board's characteristics.
Current surfboard construction techniques tend to strongly couple these board characteristics together. For example, increasing the strength against breakage typically increases the weight of the board and the moment of inertia, and reduces flexibility. The usual consequence for most types of waves is a reduction in maneuverability and a reduction in flotation. On occasion, all of these factors come together to produce a board that meets or exceeds the riders preference desires and expectations. But these boards-frequently referred to as “magic” boards—are rare and, given typical manufacturing tolerances, difficult or nearly impossible to reproduce.
Alternatively a foam core like polystyrene can be used and can alternative be covered with higher density foam and either covered with fiberglass and a curable resin or a combination of epoxy resins and fiberglass and/or plastic outer covers.
A number of construction methods are now being used to manufacture hollow boards. Composite foam sandwich or honeycomb core skin methods are combined with a mold and an internal pressure bladder to form, combine, and cure top and bottom sections to produce the shaped board. An alternative product combines pre-formed and cured sections that are then combined together in a perimeter assembling ring mold for joining, sealing and finishing of the final board.
A molded surfboard can be manufactured in a variety of ways. One manufacturing method is to form combinations of one or more materials such as plastics or composites such as fiberglass, carbon fiber, Keviar, micro sphere materials such as Sphere-a-tex, Nomex® honeycomb, aluminum honeycomb, foams cores and sheets made from polyurethanes and polystyrenes and foam or materials chemistries. This construction method can form laminates consisting of an outer skin and a center core with an inner skin to create a three dimensional structural laminate that forms the top and bottom surface of the craft. Alternatively boards can be molded by placing an uncured polymer resinous gel coating material on a preformed mold cavity and then placing on top of the gel coat an uncured polymeric resinous saturated substrate fibrous layer, and then onto the previous layers a resinous saturated substrate fibrous three dimensional layer. This multi-layer composite can then be cured under pressure employing a process such as vacuum bagging. Other molded craft construction methods include solid polystyrene foam cores with outer layers and or laminates of plastics and or composites such as those listed above.
The benefits of the present invention result from the use of advanced materials coupled with engineered suspension to improve on both the traditional solid foam core and fiberglass construction and the solid core molded and molded hollow boards. These factors are significant improvements for the industry and consumer over prior products.
In one embodiment of this invention the boards are characterized by an external carbon composite tube-like structures or exo-skeletal structures to control and respond to the flex movements and support the rider in some instances over the board. This various combination of board flex movement controls claimed in this invention include the flex control of the main planing area under the rider's feet land the increased control of the flex movements of the total board in both flex speed and board movement. This area under the rider's feet is termed the boards planing area or speed spot. This inventions suspension area under the back and front feet of the rider as well as the optional edge or rail area is designed to serve two main functions. First to provide a controllable master flex control system and second this will in turn provide increased board performance and durability
In one embodiment of this invention the suspension system is a main longitudinal carbon fiber tube of various shapes including oval, round, square or rectangular or combinations of these shapes. The tubes can incorporate varying composite materials including carbon and/or fiberglass wall thicknesses, with thinner top and bottom tube wall thicknesses, and/or internally varying wall constructions. In the case of the round tube an internal tapering wall can be incorporated with a thicker wall at the rear and a progressively tapering thinner wall forward. This thicker wall tube area provides the suspension board with an increased or higher loading capabilities and faster movement speeds in the up and down flex properties. The oval tube also can continuously taper in its overall height progressing forward towards the nose of the board. Dimensional changes in the height of the tube moving forward can reduce the suspension effects in the nose of the board. This serves a number of purposes such as a transition zone in the rigidity properties of the tube to reduce the likelihood of the board breaking at the tubes forward termination point. This also serves to reduce the abrupt termination feel of the tube for the rider in the nose area of the board. The reduced tapering forward tube allows the nose of the board to move or flex more resulting in a variety of beneficial factors such as movement in steep turns on the wave face. These exo-skeletal composite structures may be connected in a variety of configurations to one another including but not limited to the forming of integrated structure supporting the front and back foot of the rider and connecting then to the additional outer composite exo-skeletal tubelike structures.
Additionally, in an optional embodiment of the invention, the composite tube or tube-like structure or structures may be combined with a wood or composite stringer in the nose and tail area of the board. This system can be used as a replacement for the traditional wood stringer system. This composite stringer can be made from epoxy saturated and vacuum bagged micro spheres with additional woven carbon cloth placed in strategically needed reinforced areas. The micro spheres have some wood-like movement properties and they can be shaped and sanded. Unlike wood the stringer micro sphere structure is very uniform in its properties resulting in consistent performance and retention of its flex characteristics over many more flex cycles.
The main suspension composite structure or structures and or alternitive structures that may include vertical structure or structures may be incorporated and located in alternative areas such as off center and/or on the edge or rail areas of the board.
In an alternative embodiment of this invention the suspension board may be equipped with optional hydro fins or high lift force fins removable connected directly to the suspension system at the fin board interface. The suspension and foil connection tubes intersect and are coupled with the main suspension tube stringer elements. This integration of the system is the structural and control backbone that provides very small but very quick initial and return movements of the high lift wing foil sections. These small but fast wing foil section movements are critical given the magnitude of the lift force that can be generated by the foil, and the lift force sensitivity to the slightest change in the angle of attack. The torsional and side-to-side forces involving the suspension tubes at their attachment points and intersections are substantial. Under the conditions of the combined use of the invention's wing foil sections and the suspension elements. The forces or the magnitude of the lift force that can be generated by the foil thought the slightest change in the angle of attack can break or produce significant distortions in traditional board construction materials. These forces may be developed either under the control the rider or may be due to undesired hydrodynamic and rider directional changes. The combination of the inertial and hydrodynamic forces needs to transfer through the suspension structure with a minimum loss of energy. At the same time, the flex movements required for the increased thrust need to be preserved. These alterations of the boards flex movements involving the degree and speed of flex thru the installation of the suspension system produces a faster, more lively, more responsive, and more “springy” board.
The optional fin connection portion of the suspension system attaches to the fins or to the fin attachment box receivers and in so doing reduces the side-to-side movements of the fins—particularly the side fins. This fin suspension attachment system also provides for some of the up and down fin and board rail movement found in the traditional board construction methods. This stabilizing or controlling of the cross board movement is coupled with optimum flex movements of the front and back foot planing areas through the main carbon tube and stringer system. This provides faster speed in general and particularly from one maneuver to the next maneuver.
Experience shows that an occasional board will have exceptional performance qualities. These boards are commonly referred to as “magic boards”. It is common knowledge that most surfboards manufactured are generally not reproduced with sufficient accuracy to result in the same magic-like performance. The suspension boards can ensure much higher numbers of “magic-like” performance surfboards for the riders.
Most, if not all, other major sports hardware devices have made the technology change from materials, such as wood and other materials to the current state of the art composites. A few examples to have made the change from wood, metal, and fiberglass construction to alloys, carbon graphite and other materials that were considered to be exotics just a few years ago include golf clubs, tennis racquets, skis, mountain bikes, snowboards, windsurfers, kite boards, motorcycles, airplanes and boats of all kinds. This is a consequence of a number of factors but is commonly related to strength to weight ratio and additionally to the flex movement characteristics that improve the performance of these products. Strength to weight ratios that translate to flex resonance, or degree and speed of flex movement, is the main factor producing the dramatic performance increases in these products. The main performance enhancement result is less weight and higher performance in power and control.
The increased speed and control of the motions of the tennis ball, golf ball and baseball are a direct result of the new alloys and composites being used in the construction of their respective striking devices. In the example of a modern composite tennis racquet hitting a tennis ball, the racquet can be moved more quickly from one end of the power stoke to the point at which it strikes the ball. The bending characteristics, or flex resonance, of the racquet as it strikes the ball is much faster in both the movement away as it contacts the ball and also as the racquet flexes back with more stored power to increase the return speed of the ball. This increased flex speed is a consequence of the increased stored power as the racquet flexes out and returns back with the additional power and speed. The increase in power and speed of the racquet hitting the ball translates in higher ball speed and control for the player.
A similar set of principles is at play with the other examples of composite sporting goods devices. The golf club strikes the ball and more energy is transmitted to the ball for reasons similar to that of the tennis racquet. In the example of a mountain bike that incorporates fork and frame suspension features, the rider is capable of significantly increased speed and control in both the uphill and downhill aspects of the sport. The additional speed and power is possible because as the rider goes faster the composite frame and suspension allow the frame to move in ways not thought-of just a few years ago. New virtual pivot point frame technology moves and returns from the movement very quickly without losing the power of the rider. With the new frame and wheel suspension and composite frames moving and returning quickly, the energy is not lost through the frame addition and the tires stay in contact with the ground. New bike suspensions keep the bike and rider more neutral for controlling the power on and off the ground for specific trail conditions. This performance increase has redefined the sport with respect to where and how the bike can now be ridden. The flex or controlled movement is designed into these products to be engineered flex resonance or degree of movement related also to movement speed. This translates into the movement characteristics of the whole device or that portion requiring the performance enhancement by using advanced engineered design and materials.
I claim as elements of this invention a High Performance Self or Wave-propelled Aquatic Device such as a Surfboard and the related manufacturing processes combined with the installation of the flex and movement engineered internal and or semi-external and or combinations of external and internal composite structural elements such as but not limited to tube-like or other elements providing a structurally integrated performance and durability enhancing composite inner strength reinforcement combined with flex control. The suspension system provides flex and resonance controlled movements and speeds of movement up and down and side to side. This composite inner tube elements system combines the engineered inner materials with outer surface materials to create an inner suspension or flexural spring control system. The composite inner element system can be constructed with a single element or multiple parts.
I claim as an aspect of this invention an element of the invention as the connecting or joining of these composite parts with one another to achieve a controlled movement or cycle and speed of motion for up and down, side to side and the various vectors of the motion that could be found and anticipated in the many movements and motions found in the use of the surfboard on an ocean wave. The benefits of the engineered inner materials combined with the outer surface materials to create an inner suspension or flex and movement suspension control system, are a reduction in the uncontrolled and unwanted deflection and or twisting of portions or the board and fins surfaces results in a loss of speed and control of the craft. An additional advantage and benefit of the invention is increased speed of the craft and of the cycle speed of movement of specific structural elements and or surfaces in the craft during both high speed and or high stress maneuvers.
The device of this invention combines fore and aft and side-to-side areas of controlled movement and stability with repeatable accuracies of bend, flex and reduction of uncontrolled distortion and thereby a reduction of water flow friction or drag and thereby increases speed performance. The inner suspension or flexural control system has a direct benefit to the use of fins and particularly to the use of high force or high lift fins such as employed in hydrofoil fin systems. This invention maximizes the use of higher efficiency, hydrodynamic lift generating fins due to the high multidirectional forces generated with these powerful factors including the foil/fin systems. This can be achieved with this invention by combining the ability to build in the exact structural reinforcement and flexural resonance control while still maintaining complete structural integrity of the craft without over-building the outer surfaces of the craft. This is due to the internal structural element that structurally integrates the forces encountered at the point of the fins and fin attachment points or, optionally, the fin holding boxes. The rider's weight and gravity forces interacting and transmitting from above, combined with the lifting and torsional fin forces coming from below, are controlled and somewhat balanced through the structurally engineered components of this invention. Through the combination of side-to-side and longitudinal placement or installation of the internal member section or sections into a molded surfboard forming an internal structural backbone and rib cage a complete structural and performance system is achieved. This internal strength and flex and movement control system connects the side fin attachment points and/or fin receiver points, or fin box system points, to one another and/or either a single or a multiple of longitudinal tubes, beams and or reinforcements in the outer skin laminate structure either on the surfaces outer or internally in the laminate, or on the inner surface of the outer skin laminate.
In another embodiment of the invention a composite backbone and cross member rib system constructed of carbon, fiberglass and composite tube like structures, is installed into a molded surfboard to create the combination of a fore and aft, and side to side movement control. This flex and movement tube control system can connect the side and back fin attachment points and or fin receiver points or fin box system attachment points to one another and to either a single or multiple longitudinal tubes or beams. These tubes may be encased or laminated into outer polyurethane, polystyrene or other foams, and these laminated or encased foam, tube structures may have a wood or composite stringer attached to the tube and laminated or encased inside or outside the foam and carbon/fiberglass tubes.
In another embodiment of the invention the flex and movement tube control system connects the side and back fin attachment points and or fin receiver points or fin box system attachment points to one another and or either a single or a multiple of longitudinal tubes or beams. The tubes and their attachment points to the fin attachment area can be connected through a series of machined or molded connectors allowing for more movement and/or increased restriction of movement. These tubes or tube like members may be encased or laminated into outer polyurethane, polystyrene or other foams, and these laminated or encased foam, tube structures may have a wood or composite stringer attached to the tube and laminated or encased inside or outside the foam and carbon/fiberglass tubes.
In another embodiment of the invention a backbone and cross member rib system is installed into a molded surfboard to create the combination of a fore and aft and side-to-side to side and up and down movement control or the board. This flex control connects the side and back fin attachment points and/or fin receiver points or fin box system attachment points to one another and/or either a single or multiple longitudinal incorporating progressive with board movement suspension system. This structural element control connects the side fin attachment points and or fin receiver points or fin box system points to one another and or either a single or a multiple of longitudinal tubes. Tubes may be installed in either the foam blowing stage or prior to the joining of the two halves by routing the main tube and driving the rear foil fin tubes into the foam.
