1. Field of the Invention
The present invention relates generally to field hockey sticks, and more particularly, to back and edge weighted field hockey sticks.
2. Background of the Invention
As shown in
Traditionally, field hockey sticks have been constructed of relatively standard dimensions, due primarily to widely accepted rules of the game. These rules dictate aspects of the stick such as weight, length, shape, and cross section. As one example, the rules require that the playing portion of the stick have a flat face and that every cross section of the stick be able to pass through a two-inch ring. In meeting these rules, the traditional field hockey stick has typically featured a flat front face and a curved back and back head of a relatively uniform shape.
The total weight of a field hockey stick as defined by widely accepted rules must not exceed 737 grams. Within these parameters, field hockey sticks, including field hockey stick heads that are curved and have rounded backs, have a traditional shape and weight disbursement.
In the game of field hockey, players typically favor passes and shots that are hard and low. Indeed, the more powerful the drive, the better chance the pass or shot has of eluding defenders. This increase in power, however, also increases the chance of losing control of the ball, especially in terms of lofting the ball illegally. These passes and shots are hit from an upright standing position and the ball must travel on or near the ground in a relatively straight line. A miss-hit ball often rises up in the air above knee level, which can result in the loss of possession and can be harmful to other players. Thus a principal object of powerful drives is to keep the ball close to the ground. The object is to hit the ball hard but minimize its loft. Shooting low and hard on goal can significantly increase the chances of scoring, either through deflected shots or from rebounds off of the goalie. Keeping the ball low helps control passes and shots, while not violating game rules against lofted balls, which result in the opposing team gaining possession of the ball. Players therefore prefer field hockey sticks that meet this need.
Field hockey sticks are typically made of wood or composites. As used herein, composites refer to field hockey sticks made by bladder molding or by laying up. Bladder molding processes use an air bladder, a two-part female mold, composite material, and resin. The bladder is inflated, thus creating pressure to force the composite and resin against the mold until it cures, thereby forming a hollow field hockey stick. In laying up composites, sheets of uncured fiber-reinforced thermosetting resin are wrapped around a mandrel, which is then withdrawn to form a hollow tubular lay-up. By either process, traditional, hollow composite field hockey sticks typically have generally constant wall thicknesses. Examples of the materials used in the resin include fiberglass, carbon, and aramid. Composite sticks have been available on the market for several years and have been approved for use in international play for over a year.
It is widely believed that composite sticks generate more powerful drives than wooden sticks. Offsetting this additional power, however, composite sticks, because of their hollow interiors, can vibrate undesirably and provide less feel for the ball. Minimizing these effects would therefore allow players to deliver a more powerful drives without sacrificing comfort or ball control. In addition, the ball tends to bounce off the stick when a player is trying to stop the ball. This is a significant disadvantage, as the player can lose control of the ball and even possession of the ball.
The present invention provides back and edge weighted field hockey sticks. In an embodiment of the present invention, the interior walls of a typical hollow composite field hockey stick are reshaped to redistribute weight to desired areas of the field hockey stick, such as along the edges of the throat and head in the case of edge weighting, or along the center of the back non-playing side of the stick in the case of back weighting. Unlike conventional composite field hockey sticks, which have wall thicknesses that are relatively constant, the present invention varies the wall thickness to redistribute the weight of the stick and provide desirable playing characteristics such as reduced vibration and enhanced feel for ball contact. In redistributing the weight, the overall weight of the field hockey stick preferably remains the same, to comply with commonly accepted rules of field hockey stick construction. Thus, as thicknesses in some areas of a stick are increased, thicknesses in other areas can be reduced.
In one embodiment of the present invention, the thickness of the interior wall of the round non-playing side of the head and throat is increased to give a field hockey stick a back weighted feel. This back weighting can increase the dead spot on the stick, which is the area on the face of the stick where the ball does not bounce at all when it hits the stick. At the dead spot, substantially all of the energy is absorbed by the stick and essentially no energy is transferred to the ball. This effect occurs because, at this point on the stick, the efficient mass of the stick is equal to the efficient mass of the ball. Another benefit in increasing the dead spot on the stick is that, when hitting the ball, substantially all of the energy is transferred from the stick into the ball, creating a more powerful hit. In this embodiment, the field hockey stick can comprise a head, a throat adjoining the head, and a handle adjoining the throat opposite the head. The throat and head have a playing side (e.g., flat) and a non-playing side (e.g., round or curved). In a cross section of the throat taken perpendicular to the longitudinal axis of the throat, the thickness of the non-playing wall is greater than the thicknesses of the playing wall and the two edge walls. For example, the non-playing wall could be 1/16″, ⅛″, or ¼″ thicker than the other walls. A similar increase in wall thickness can be provided through the head and/or the handle if desired.
In another embodiment of the present invention, the thicknesses of the interior walls of the edges of the field hockey stick are increased to give a field hockey stick an edge weighted feel. The advantage of a peripheral weighted stick is that the moment of inertia of the stick is increased, which reduces twisting and off-center hits. In essence, a peripheral weighted stick can have a more accurate and controlled hitting surface because the center of gravity can be located on the hitting surface. When the ball is hit off of the center of gravity, it moves in a relatively straight direction away from the point at which contact was made. In this embodiment, the field hockey stick can comprise a head, a throat adjoining the head, and a handle adjoining the throat opposite the head. The throat and head have a playing side (e.g., flat) and a non-playing side (e.g., round or curved). In a cross section of the throat taken perpendicular to the longitudinal axis of the throat, the thicknesses of the two edge walls are greater than the thicknesses of the playing wall and the non-playing wall. For example, the two edge walls could be 1/16″, ⅛″, or ¼″ thicker than the other walls. A similar increase in wall thickness can be provided through the head and/or the handle it desired.
Traditionally the center of gravity in the head of a field hockey stick has been designed so that it is in line with or below the center of gravity of a field hockey ball, when both the head and the ball are resting on the same plane. The circumference of a field hockey ball is typically about 8.8125 to 9.25 inches, with a radius to its center of about 1.40 to 1.47 inches. Therefore, the head of a traditional field hockey stick typically has a center of gravity within about 1.47 inches from the bottom of the head. As used herein, center of gravity refers to the point at which the entire weight of a body may be considered as concentrated so that, if supported at this point, the body would remain in equilibrium in any position. By raising the center of gravity of the head, embodiments of the present invention change the moment of impact on a ball and its resultant launch angle. The higher that the center of gravity of the head is above the center of gravity of the ball, the lower the launch angle on the ball will be.
Embodiments of the present invention raise the center of gravity in a field hockey stick head by one or more of the following methods: 1) removing material from a part of the head; 2) adding material to a part of the head; 3) repositioning or redistributing material in the stick, such as in the areas of the head and the throat; 4) using two or more materials with different mass or density properties in the head; and 5) combinations thereof.
Composite field hockey sticks are traditionally manufactured by a process referred to as bladder molding, which uses an air bladder, a two-part female mold, composite material, and resin. The bladder is inflated, thus creating pressure to force the composite and resin against the mold until it cures. This process results in a hollow hockey stick.
According to an embodiment of the present invention,
As shown in the example of
The depressions 203 in head 206 minimize the mass of the lower portion of head 200, and therefore raise the center of gravity of head 206 to above the traditional center of gravity that is in line with the center of gravity of a field hockey ball. Line 214, which is drawn at roughly the center of gravity of a field hockey ball (e.g., 1.40 to 1.47 inches), represents the line above which the center of gravity of head 206 is disposed, according to an embodiment of the present invention. For example, with depressions 203, the center of gravity of head 206 could be disposed at about 1.5 inches from the extreme end 209 of head 206.
The placement of depressions 203 raises the center of gravity of head 206, such that the center of gravity of head 206 is higher in relation to a ball struck by head 206, in comparison to traditional field hockey sticks. This higher center of gravity helps minimize the loft imparted on the ball. In one embodiment, depressions 203 are disposed within about 1.47 inches from end 209.
According to a particular implementation of the present invention, the center of gravity of head 206 is above a line drawn halfway between the highest point 210 of toe 208 and the extreme end 209 of head 206 opposite to point 210, when the distance between end 209 and point 210 is approximately 3.94 inches (which is the maximum distance allowed by widely accepted rules of field hockey). Such a line would be about 1.97 inches from end 209.
Depression 411 could be oval-shaped as shown in the example of
Disposing depression 411 in throat 404 reduces the mass in throat 404 and redistributes this removed mass to the upper portion of the head 406. Line 414, which is drawn at roughly the center of gravity of a field hockey ball (e.g., 1.40 to 1.47 inches), represents the line above which the center of gravity of head 406 is disposed, according to an embodiment of the present invention. For example, with depression 411, the center of gravity of head 406 could be disposed at about 1.5 inches from the extreme end 409 of head 406. Adding the mass to the top portion of head 406 raises the center of gravity of head 406. Consequently, head 406 can strike a ball with a higher center of gravity and minimize loft on the ball.
According to a particular implementation of the present invention, the center of gravity of head 406 is above a line drawn halfway between the highest point 410 of toe 408 and the extreme end 409 of head 406 opposite to point 410, when the distance between end 409 and point 410 is approximately 3.94 inches (which is the maximum distance allowed by widely accepted rules of field hockey). Such a line would be about 1.97 inches from end 409.
In a further alternative embodiment, instead of or in addition to removing and redistributing mass of a field hockey stick, mass could be added to the stick. For example, a metal (e.g., lead), thermoplastic elastomer (TPE), or other material could be attached to the upper portion of the head of the stick. For example, a plug made of a second material could be embedded (e.g., by laying up the plug) in the upper portion of the head. This additional material would raise the center of gravity of the head.
According to a particular implementation of the present invention, the center of gravity of head 1006 is above a line drawn halfway between the highest point 1010 of toe 1008 and the extreme end 1009 of head 1006 opposite to point 1010, when the distance between end 1009 and point 1010 is approximately 3.94 inches (which is the maximum distance allowed by widely accepted rules of field hockey). Such a line would be about 1.97 inches from end 1009.
Another alternative embodiment of the present invention provides a field hockey stick with perimeter weighting, while still raising the center of gravity of the head. This perimeter weighting can improve the feel and control of the stick. As an example,
An embodiment of the present invention uses composite materials to construct a field hockey stick having a top weighted head. The composites enable a gradual redistribution of the mass of the field hockey stick, while still providing the requisite degree of strength in the areas from which mass is moved. For example, with the embodiment providing a depression in surface of the round throat back, the mass in the throat can be moved downward to the head with gradual, undulating shapes, leaving a relatively thin area (e.g., thin wall thickness and/or thin edge width as shown, for example, in
Although discussed primarily in the context of composite field hockey sticks, one of ordinary skill in the art would appreciate that the present invention could apply equally well to field hockey sticks made of other materials, such as wood. In such cases, the throat and head depression(s) would be formed as appropriate for the material. For example, depressions could be carved out of a traditional wood field hockey stick.
A further embodiment of the present invention achieves a higher center of gravity by varying the material composition of the head. For example, the lower portion of a head could be made of a first material, and the upper portion of the head could be made of a second material that is heavier than the first material. In this manner, the center of mass or gravity could be raised on the head without necessarily using depressions (as in
Thus, the top weighted field hockey sticks of the present invention provide a player with improved comfort, feel, and playability. In particular, the present invention raises the center of gravity of a field hockey stick head to minimize loft and impart an improved feel when striking a ball with the stick.
In accordance with another aspect of the present invention, mass may be redistributed toward the back, non-playing side of the field hockey stick (back weighting) or toward the edges of a field hockey stick (edge weighting). For example, the mass 1050 in
Likewise, additional mass may be placed along the edges of the stick, for example in the throat or head, resulting in increased edge wall thicknesses and an edge weighted field hockey stick. For example, in
Unlike traditional, hollow composite field hockey sticks having generally constant wall thicknesses, embodiments in accordance with this aspect of the present invention vary the wall thickness to redistribute the weight of a field hockey stick. This weight redistribution provides different performance characteristics, especially in terms of how the field hockey stick feels to a player when the stick contacts a ball. Preferably, this weight redistribution is accomplished without changing the overall weight of the field hockey stick, to ensure compliance with widely accepted field hockey rules limiting the weight of sticks.
An embodiment of the present invention modifies conventional composite manufacturing processes to provide varying wall thicknesses. With laying up processes, for example, a mandrel around which resin is wrapped can be configured with depressions on certain sides, which increase the thickness of the walls on those sides. Alternatively, an ordinary mandrel can be used and more resin can be applied to one side of the mandrel. As another example, with a bladder molding process, more resin can be applied to certain walls of the mold to create different wall thickness when the air bladder is inflated and forces the resin against the mold.
In contrast,
One of ordinary skill in the art will appreciate that, although both edges 1224 are shown in the figures as being of equal thickness, one or the other of the edges 1224 may be thicker than each of the playing side 1222 and the non-playing side 1226. Moreover, both edges 1224 may be thicker than each of the playing side 1222 and the non-playing 1226, while one of the edges 1224 is thicker than the other edge 1224.
The variable wall thicknesses of
Other combinations may include integrating the back weighted cross section of
In addition, although
As shown in
An embodiment of the present invention uses composite materials to construct back and edge weighted field hockey sticks. The composites enable a gradual redistribution of the mass of the field hockey stick, while still providing the requisite degree of strength in the areas from which mass is moved. For example, with the embodiment providing an increased wall thickness for the back non-playing side of the throat, the mass in the throat can be moved away from the other sides and to the back with gradual shapes, leaving the other sides thinner area but still structurally strong enough to withstand the rigors of the game. The gradual reshaping and redistributing of material also enables the provision of cross sectional dimensions that comply with the traditional two-inch ring test.
Although discussed primarily in the context of composite field hockey sticks, one of ordinary skill in the art would appreciate that the present invention could apply equally well to hollow field hockey sticks made of other materials, such as wood. In such cases, the wall thicknesses would be formed as appropriate for the material. For example, walls could be carved out of wood.
The foregoing disclosure of embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be apparent to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims, and by their equivalents.
Further, in describing representative embodiments of the present invention, the specification may have presented the method and/or process of the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention.
This application is a continuation-in-part of U.S. patent application Ser. No. 11/030,953, filed Jan. 10, 2005, which claims the benefit of U.S. Provisional Application No. 60/534,968, filed Jan. 9, 2004, both of which are herein incorporated by reference in their entirety. This application also claims the benefit of U.S. Provisional Application No. 60/707,172, filed Aug. 11, 2005, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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60534968 | Jan 2004 | US | |
60707172 | Aug 2005 | US |
Number | Date | Country | |
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Parent | 11030953 | Jan 2005 | US |
Child | 11501708 | Aug 2006 | US |