Patent Document:

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 , the present invention changes 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 , fig2 illustrates an example of how to raise the center of gravity of a composite field hockey stick head by taking advantage of the hollow area inside the head . by strategically placing contours in the molds , the present invention shifts where the composite fills the mold . thus , by not allowing the bottom portion of the head to fill with composite , the mass of the head is disposed higher on the head . to further enhance the reallocation of mass in the head , extra material , such as more resin , can also be added to the head before or after molding . as shown in the example of fig2 , one embodiment of the present invention provides a field hockey stick 200 having a head 206 with one or more depressions 203 in its surface . in this example , head 200 has three depressions 203 , which are generally oval in shape . the outside and inside ovals shown for each depression 203 indicate generally where each depression begins to descend ( outside line ) and then levels out somewhat ( inside line ) to form the base of the depression . fig3 illustrates a side view of field hockey stick 200 , showing the depression 203 nearest the toe 208 . the depressions could , of course , be formed in many different numbers and shapes , for example , having a single rectangular depression with planar sloping walls , instead of rounded walls . 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 . fig4 illustrates another embodiment of the present invention in which the mass of the throat of a field hockey stick is reduced and shifted toward the upper portion of the head . as shown in this example , a field hockey stick 400 includes a depression 411 in the surface of its throat 404 . depression 411 can be disposed in throat 404 closer to head 406 than to a handle ( not shown ) attached to throat 404 . depression 411 can be disposed either in the flat playing side of throat 404 or , as shown in fig4 , in the round non - playing side of throat 404 . depression 411 could be oval - shaped as shown in the example of fig4 . the outside and inside oval - shaped lines shown for depression 411 indicate generally where depression 411 begins to descend ( outside line ) and then levels out somewhat ( inside line ) to form the base of the depression 411 . fig5 illustrates a side view of field hockey stick 400 , further showing the exemplary shape of depression 411 . depression 411 could , of course , be formed in many different numbers and shapes , for example , having multiple tear - shaped depressions . disposing depression 411 in throat 404 removes mass from throat 404 in the area just above the head 406 , 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 . fig6 and 7 illustrate a further embodiment of the present invention in which a field hockey stick 600 has both a depression 611 in its throat 604 and also one or more depressions 603 in its head 606 . as discussed above in reference to fig2 - 5 , depression 611 and depressions 603 redistribute mass of the field hockey stick 600 to the upper portion of its head 606 . having mass redistributed by both depression 611 and depressions 603 accentuates the center of gravity situated in the upper portion of head 606 . fig8 - 9 illustrate alternative embodiments of the present invention having different numbers and shapes of depressions on the head of a field hockey stick . for example , fig8 illustrates a field hockey stick 800 having a head 806 with a single irregularly shaped depression 803 in its extreme end ( opposite to the handle , not shown ). as another example , fig9 illustrates a field hockey stick 900 having a head 906 with five roughly triangular depressions 903 . 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 . fig1 illustrates an example of this embodiment , in which a field hockey stick 1000 has a head 1006 with a mass 1050 added to the upper portion of the head . line 1014 , 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 1006 is disposed , according to an embodiment of the present invention . for example , with mass 1050 added , the center of gravity of head 1006 could be disposed at about 1 . 5 inches from the extreme end 1009 of head 1006 . 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 , fig1 illustrates a field hockey stick head 1106 having a distal member 1102 and a depression 1104 . as described above , depression 1104 enables the redistribution of mass to the upper portion of head 1106 to raise the center of gravity . at the same time , distal member 1102 provides a mass at the end of head 1106 that affords a perimeter weighting for the field hockey stick . although fig1 shows distal member 1102 in one particular form , many different forms of perimeter weight could , of course , be used , such as flanges , ribs , rims , or plugs . plugs could be made , for example , of material heavier than the remaining material of the head . 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 where the mass is removed that is still structurally strong enough to withstand the rigors of the game . the gradual reshaping and redistributing of material also enable 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 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 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 fig2 ) or adding a mass ( as in fig1 ). in the case of a composite stick , for example , lighter fibers could placed in the lower portion of the head , with heavier fibers located in the upper portion of the head . heavier materials could also be laid up within the fibers to provide areas of greater mass in the upper portion of the head . similarly , plugs made of heavier or lighter materials could be strategically positioned in the head to provide a raised center of gravity . 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 . 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 .

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