Patent application title: Hockey Stick Blade Having Fiber-Reinforced High Density Foam Core
Isaac Garcia (San Diego, CA, US)
IPC8 Class: AA63B5914FI
Class name: Club having elongated blade (e.g., hockey stick, etc.) blade construction or accessory
Publication date: 2009-06-11
Patent application number: 20090149284
A composite hockey stick blade including a fiber reinforced, high-density
foam polymeric core material overlaid with a plastic wrap. The fiber
reinforcement material, in the form of a plurality of milled or long
fibers, provides increased toughness and stiffness of the high density
polymeric foam core material. The hockey stick blade may be utilized as a
replacement blade for a two-piece hockey stick, or may be a portion of a
one-piece hockey stick.
13. A method for forming a composite hockey stick blade having a hosel, a heel section, and a paddle portion, the method comprising:providing a multi-piece mold having an inner cavity defined therewithin, said inner cavity shaped to correspond in size and shape to the composite hockey stick blade;coupling one or more plies of a plastic wrap along a front surface and a rear surface of said inner cavity, said front surface corresponding to a front face of the paddle portion and said rear surface corresponding to a rear face of the paddle portion;coupling one or more strips of reinforcement along a bottom surface of said inner cavity, said bottom surface corresponding to a bottom edge of the paddle portion;coupling a fiber reinforced high density polymeric foam core section onto said innermost one of said one or more strips of reinforcement between said one or more plies along said front surface and said one or more plies on said rear surface;coupling at least one ply of said plastic wrap onto a top surface of said fiber reinforced high density polymeric foam core section;closing said multi-piece mold such that said fiber reinforced high density polymeric foam core section contacts one said plies of plastic wrap along said front surface and said rear surface, said fiber reinforced high density polymeric foam core section also contacting one of said one or more strips of reinforcement along said bottom edge and further contacting one of said at least one ply along said top surface;applying heat and pressure within said multi-piece mold for a period of time sufficient to cure said fiber reinforced high density polymeric foam core section, said one or more plies of said plastic wrap, and said one or more plies of said reinforcement;opening said multi-piece mold; andremoving the composite hockey stick blade.
14. The method of claim 13, wherein said fiber reinforced high density polymeric foam core section comprises a high density epoxy foam and a plurality of chopped fiber.
15. The method of claim 14, wherein said plurality of chopped fibers comprises a plurality of milled fibers.
16. The method of claim 14, wherein said plurality of chopped fibers comprises a plurality of long fibers.
17. The method of claim 14, wherein said plurality of milled fibers comprises between about 0 and 5 weight percent of said fiber reinforced high density polymeric foam core section.
18. The method of claim 13, wherein said fiber reinforced high density polymeric foam core section comprises a high density, non-expanding epoxy foam and a plurality of chopped fiber.
19. The method of claim 13, wherein said fiber reinforced high density polymeric foam core section comprises a high density expanding foam and a plurality of chopped fiber.
20. The method of claim 13, further comprising:providing a second cavity portion within said multi-piece mold that is open and continuous with said inner cavity, said second cavity portion corresponding to a hosel region of the composite hockey stick blade;coupling one or more plies of said plastic wrap to each of the outer surfaces of said second cavity portion; andoptionally inserting a silicone plug within said one or more plies of said plastic wrap with said second cavity portion.
21. The method of claim 20 further comprising:coupling a foam core section within said second cavity portion.
The present invention relates generally to a hockey stick blade and, more particularly to, a hockey stick blade having a fiber reinforced high density foam core.
BACKGROUND OF THE INVENTION
Typical current hockey stick blades or replacement blades are generally made of a core material reinforced with one or more layers of synthetic material, such as fiberglass, carbon fiber or graphite. Traditionally, the core of the blade has been made of natural materials, such as wood or a wood laminate. Traditional wood constructions, however, are expensive to manufacture due to the cost of wood and the manufacturing processes employed. Further, wood sticks and blades are relatively heavy and have somewhat limited durability. Finally, due to variabilities relating to wood construction and manufacturing techniques, wood sticks are difficult to manufacture with consistent tolerances, and even the same model and brand of sticks and blades may have differences in terms of mechanical properties, such as stiffness and curvature.
Recently, in an attempt to decrease the weight of the stick and blade, and to improve upon the durability and mechanical properties associated with the performance of the stick or blade, alternative core materials, such as synthetic materials reinforced with layers of fiber material, have been utilized. The fiber layers are usually made of woven filament fibers, typically soaked in a resin and glued to the surfaces of the core of the blade. Expandable fiber braids have also been used for covering the core of the blade. These composite sticks and blades have proven to have improved durability versus traditional wooden sticks and blades and have many of the mechanical attributes desired by hockey players. Further, these composite sticks and blades have less variability in terms of tolerances related to curvature and stiffness.
Nevertheless, these sticks and blades still have disadvantages. For example, conventional foam core materials form blades are formed of polymeric materials that are limited in strength and durability by a combination of factors, including the type and density of the polymeric material forming the foam core, the thickness of the foam core, and the amount of curing of the foam core during processing.
Accordingly, there is a demand for a composite blade having improved strength and durability, and hence improved playability characteristics, that utilizes conventional polymeric foam core materials and conventional forming techniques. These playability characteristics include improved response while handling and/or shooting a puck, the prevention of puck "flutter" that may occur when a player shoots or passes the puck, and the twisting of the blade as a puck is passed or shot.
SUMMARY OF THE INVENTION
It is therefore an advantage of the present invention to provide a composite blade for a hockey stick with improved response while handling and/or shooting a puck.
It is another advantage of the present invention to provide a composite blade for a hockey stick that assists in preventing puck "flutter" that may occur when a player shoots or passes the puck.
It is a related advantage of the present invention to provide a composite blade for a hockey stick that minimizes twisting of the blade.
It is still another advantage of the present invention to provide a composite blade for a hockey stick that has decreased weight without adversely affecting the performance or mechanical characteristics of the blade.
In accordance with the above and the other advantages, the present invention provides a composite hockey stick blade having a high density foam core paddle coupled overlaid with, or coupled within, a plastic wrap. In addition, reinforcing materials such as chopped fibers are introduced to the high density foam core material to increase the toughness and durability of the blade to better withstand the rigors of play. The presence of the high density foam and fiber reinforcement allows the thickness of the plastic wrap to be decreased along the front face and rear face of the paddle while maintaining the desired performance and mechanical characteristics of the blade. The result is a durable, stiff, and light blade that can be formed as a part of a hockey stick or as a separate replacement blade for a hockey stick.
These and other features and advantages of the present invention will become apparent from the following description of the invention, when viewed in accordance with the accompanying drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a view of the backside face of a blade according to one embodiment of the present invention;
FIG. 2 is a cross-sectional view of a portion the blade of FIG. 1 in the direction of arrows 2-2; and
FIG. 3 is a cross-sectional view of a two-piece mold used to form the blades of FIGS. 1-2 in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the FIGS. 1-2, a hockey blade 10 is depicted in accordance with a preferred embodiment of the present invention. It should be understood that while the preferred blade is intended for use in the sport of ice hockey, it can also be utilized in other sports, including roller hockey and field hockey. In general, the blade 10 comprises a hosel 12, a heel section 14, and a paddle (blade portion) 16. The heel section 14 is located at the junction of the hosel 12 and the paddle 16. The hosel 12 includes a tenon 18, or insert, adapted to be inserted into a hollow hockey stick shaft (not shown) made of aluminum, composite or graphite. It will be understood that the hockey stick shaft can be made of a variety of other materials, including but not limited to wood or wood laminate. The paddle 16 includes a front face 20 and a rear face 22 and further comprises a top edge 24, a tip region 26 and a bottom edge 28.
The blade 10, as shown in FIG. 2, is preferably formed as a composite structure having an inner foam core 100 overlaid with, or sandwiched within, with a plastic wrap 101. The hosel 12 and tenon 18 are preferably formed having one or more layers of the plastic wrap (shown as a plurality of plies 197 in FIG. 3) that are wrapped around a hollow cavity and may include an inner foam core (shown as 199 in FIGS. 1 and 3).
The inner foam core 100 and foam core 199 (when present) are constructed of formulations of syntactic foam or non-syntactic polymeric foam, with syntactic foams preferred. A syntactic foam is formed by filling a polymeric matrix material with hollow particles called microballoons. The presence of microballoons results in lower density, higher strength, and lower thermal expansion coefficient core materials, which is desirable for hockey stick blades. The microballoons used in the present invention are typically glass microballoons or polymeric microballoons such as polypropylene microballoons.
The polymeric matrix material used in the inner foam core 100, 199 is preferably a high-density polymeric material that cures to form a relatively lightweight, durable, flexible, and tough core. Preferably, the high-density polymeric matrix material is non-expandable foaming material. The term high-density, in the context of the present invention, is meant to describe a foam material having a density of at least about 30 pounds per cubic foot. The term non-expandable, in the context of the present application, is meant to describe a polymeric material that maintains its general shape after curing. Thus, in the present invention, a non-expandable foam core blade will maintain its general shape after being removed from the mold in which it is formed, regardless of the temperature at which it is removed (i.e. the polymeric matrix material will not expand after it is cured and removed from the mold). One such non-expandable polymeric material is high-density epoxy, which foams and cures to form a blade 10. However, other polymeric materials, or blends of polymeric materials, or different forms of the general polymeric composition, and having one or more of these characteristics, is specifically contemplated by the present invention.
Chopped reinforcing fibers 167, in the form of long or short (milled) fibers, are also preferably introduced to the inner foam core 100 and/or the foam core section 199 to provide additional durability and/or stiffness to respective core 100 and 199. The types of chopped reinforcing fibers 167 that may be used include carbon fiber, graphite fiber, aramid fiber, glass fiber, polyethylene fiber, ceramic fiber, boron fiber, quartz fiber, polyester fiber or any other fiber that may provide the additional desired strength to the blade 10.
In one preferred embodiment, milled carbon fiber is introduced at a ratio of about 5% by weight of a non-expandable, syntactic high-density epoxy foam inner foam core 100 or the foam core section 199. In yet a more preferred embodiment, milled carbon fiber ( 1/32'') is introduced at a load of 1.7% by weight of the syntactic, non-expandable high density epoxy (greater than about 30 pounds per cubic foot and 0.55 SG) inner foam core 100 and/or the foam core section 199.
The plastic wrap 101 is preferably a fiber-reinforced prepreg material that includes one or more layers 102 comprising one or more plies 104 of substantially continuous fibers 106 disposed in a matrix or resin based material 108.
Separate reinforcing layers 110 of the same type and quantity as plies 104 may be placed on the top edge 24 and the bottom edge 28 of the blade 10. It will be understood that the blade 10 may be formed as a replacement blade, i.e. separate from the shaft, or may alternatively be formed as a single integral unit with the shaft. Moreover, it will be understood that the inner foam core 100 may be reinforced with materials other than plastic wrap 101 in other ways well known to those of ordinary skill in the art and is not meant to be limited to the preferred embodiment.
The fibers 106 employed in plies 104, 197 may be comprised of carbon fiber, graphite fiber, aramid fiber, glass fiber, polyethylene fiber, ceramic fiber, boron fiber, quartz fiber, polyester fiber or any other fiber that may provide the desired strength. In addition, fiber may also be added to the outermost ply 104, 197 to form a decorative appearance. For example, a graphite fiber outer ply preferably constitutes the outermost ply 104 of the paddle 16 to provide an aesthetically pleasing appearance.
The matrix or resin based material 108 is preferably selected from a group of resin based materials, including thermoplastic materials such as polyetheretherketone ("PEEK"), polyphenylene sulfide ("PPS"), polyethylene ("PE"), polypropylene urethanes ("PPU"), and nylons such as Nylon-6. The matrix or resin based material 108 may also include or be entirely composed of a thermosetting material, such as urethanes, epoxy, vinyl ester, polycyanate, and polyester.
In order to avoid manufacturing expenses relating to transferring the resin into the mold after the foam-fiber layers are inserted into the mold, the matrix material 108 employed is preferably pre-impregnated into the plies 104 prior to the uncured blade assembly being inserted into the mold and the mold being sealed. In addition, in order to avoid costs associated with the woven sleeve materials employed in contemporary composite blade constructs, it is preferable that the layers be comprised of one or more plies 104 of non-woven unidirectional fibers. Suitable materials include unidirectional carbon fiber tape pre-impregnated with epoxy, unidirectional glass fiber tape pre-impregnated with epoxy, and unidirectional aramid fiber tape pre-impregnated with epoxy.
As used herein the term "ply" 104 shall mean a group of fibers which all run in a single direction, largely parallel to one another, and which may or may not be interwoven with or stitched to one or more other groups of fibers each of which may be or may not be disposed in a different direction. A "layer" 102 shall mean one or more plies 104 that are laid down together.
The composition of the substantially continuous fibers 106, and/or the composition of the matrix or resin based material 108, of each individual ply 104 may be similar or varied in composition to their respective adjacent ply 104. Moreover, the fiber orientation of the continuous fibers 106 within an individual ply may be the same, or varied, from the orientation of the immediately adjacent ply 104. For example, the fiber orientation of adjacent plies may be parallel to one another (i.e. the fibers are oriented at a 0 degree angle relative to the next adjacent ply, forming a 0/0 orientation), perpendicular to one another (i.e. the fibers are oriented at a 90 degree angle relative to the next ply, forming a 0/90 pattern), or may be oriented at an angle between 0 and 90 degrees (for example, at a 30 degree, or 60 degree, angle relative to the adjacent ply). In these ways, the performance characteristics of hockey blade, in terms of relative stiffness and relative durability, may be varied from blade to blade, and hence stick to stick.
Referring now to FIG. 3, one preferred method for forming the blade 10 as described above in FIGS. 1-2 is illustrated.
First, a mold 175, corresponding to the shape of the blade 10, is formed having an inner surface 180 in the form of a front surface 177, a rear surface 179, a top surface 181, and a bottom surface 183 that define a cavity 185 corresponding to the outer periphery of the front face 20, the rear face 22, the top edge 24 and the bottom edge 28. The mold 175 also includes an inner surface 187 corresponding to the outer periphery of the hosel 12, and therein defines a second cavity portion 189 that is preferably open and continuous with the cavity 185. The mold preferably consists of two or more mold pieces 191, 193 that close to define the cavities 185, 189 that corresponds to the shape of the blade 10.
Next, one or more plies 104 of a plastic wrap 101, here pre-impregnated substantially continuous fibers comprising each respective face 22 or 24 of the blade 10, are placed into the mold 175 along the front surface 177 and the rear surface 179. As stated above, a graphite fiber outermost ply is preferably introduced along the front surface 177 and rear surface to provide an aesthetically pleasing outer appearance. In addition, one or more plies 197 of the pre-impregnated substantially continuous fibers are placed onto the outer surface 187 of the hosel region within the cavity region 189.
A long strip of reinforcement 110 is placed onto the bottom surface 183 of the mold and also encloses the plies 104. The reinforcement 110 preferably consists of one or more plies of the pre-impregnated substantially continuous fibers of similar composition to plies 104 and 197.
An inner foam core material 100 is then introduced within the plies 104 within the first cavity region 185 and optionally within the plies 197 of the second cavity region 189. Finally, a second strip of the reinforcement 110 is draped over the inner foam core 100 and plies 104 and will couple to the top surface 181 of the mold 175.
Last, the plies 104 for the other face 22 or 24 of the blade 10 are added or wrapped over a foam core 100 that is generally in the shape of the blade 10 illustrated in FIGS. 1 and 2 to create an uncured blade assembly.
The mold 175 is closed using an automated press or tightened down by hand using bolts (not shown). Heat is then applied to the mold 175 sufficient to cure the inner foam core 100, the foam core 199 and the prepreg materials comprising the plies 104, 110, and 197. In the case of expanding foam materials, the curing foam material pushes against the plies 104, 110 and 197 as the material cures. Where non-expanding foams are utilized, the pressure exerted by the mold itself is sufficient to ensure that the blade is shaped in the desired manner. As one of ordinary skill will recognize, the amount of heat and time necessary to cure the inner foam core 100,199 is dependent upon numerous factors, including but not limited to the chemical composition of the foam core 100, 199, the thickness of the foam core 100, 199 and the pressure exerted within the mold.
For one preferred core material, namely a syntactic, non-expandable epoxy foam core material having a density of about 30 pounds per cubic foot (0.55 SG), the core is cured at about 150 degrees Celsius (about 300 degrees Fahrenheit) for twenty minutes.
When the mold cycle is complete, the blade 10 is then removed from the mold 175. For a blade 10 having non-expanding foam core 100,199, the blade 10 may be removed immediately. For a blade having an expanding foam core 100, 199, the blade 10 is first cooled below its curing and foam expansion temperature prior to removal from the mold 175.
After removal, the blade 10 is finished to a desired outer appearance. The finishing process may include aesthetic aspects such as paint or polishing and also may include structural modifications such as deburring.
The use of a high-density, fiber reinforced inner foam core 100 in the blade 10 allows the plastic wrap 101 thickness of the paddle 16, along the front face 20 and rear face 22, to be decreased to between about 0.045 and 0.030 inches. The reduction in thickness of the plastic wrap 101 along the front face 20 and rear face 22 forms a lighter blade 10 that provides better impact capabilities, better flex loading and forgiveness without sacrificing strength or durability, over current composite blades having lower density foam cores and a plastic wrap thickness of around 0.060 inches.
While particular embodiments of the invention have been shown and described, numerous variations or alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims.
Patent applications in class Blade construction or accessory
Patent applications in all subclasses Blade construction or accessory