NL2029127B1 - A fiber reinforced composite field hockey stick and an interchangeable weight for use in said field hockey stick - Google Patents

Abstract

The present invention is related to a fiber reinforced composite field hockey stick, comprising a shaft, having a frontal surface and a back surface, and a head, having 5 a frontal surface and a back surface, which head is connected to the shaft, wherein at least the shaft and/or the head comprises embedded reinforcing fibers, wherein at least one pre-formed recess is provided in the back surface of the shaft or the head. The invention is further related to an interchangeable weight for use in a field hockey stick according to the invention.

Description

A fiber reinforced composite field hockey stick and an interchangeable weight for use in said field hockey stick

The present invention is related to a fiber reinforced composite field hockey stick.

The invention is further related to an interchangeable weight for use in such a field hockey stick.

In the game of field hockey, a lot of development goes in the design of the stick.

These developments allow to optimize the performance of the stick in numerous ways. Albeit the developments cover a lot of different aspects of the stick, ranging from the materials used, to the shape of the different portions of the stick, the developments must be compliant with the rules of the game. Although there are different rules, the most widely known set of rules are provided by “The

International Hockey Federation’s Rules of Hockey”. This set of rules for instance sets forth that the maximum weight of a hockey stick may not exceed 737 grams.

Besides the weight of the stick also design factors such as maximum curvatures, diameters and the like are specified within the rules. Fulfilling these rules however, a very wide variety of sticks is available in the market. A drive to this wide variety of sticks are the personal preferences of hockey players. Where one player may prefer a bow of his or her stick to be located near the head, another player may prefer such bow being located closer to the upper side of the stick. Likewise, one player may prefer a relatively light stick, whilst another player may prefer a relatively heavy stick. Besides the weight, which is an important factor of preference, also the distribution of the weight over the stick may be of relevance.

Where one stick may be relatively heavy in the region of the head of a stick, another stick may for example have its weight distributed more towards the upper end of the stick. These differences in the distribution of the weight in a stick may for example be caused by the different requirements of the sticks. For example, some sticks may require a portion that is strengthened in order to be able to withstand higher forces. Due to the tendency of sticks being at least partially reinforced by fibrous material, said strengthening may consist of additional local layers of fibrous material. This however also may result in that a strengthened stick part is heavier, thereby shifting the distribution of the weight and the center of gravity of the stick.

The currently available hockey sticks are not able to coop with the individual demands of various players.

It is therefore a goal of the invention to provide a field hockey stick having a higher degree of modularity. A further goal of the invention is to provide a field hockey stick wherein such modularity is provided such that is unobtrusive with respect to a player's use of the stick.

The present invention thereto provides a fiber reinforced composite field hockey stick, comprising a shaft, having a frontal surface and a back surface, and a head, having a frontal surface and a back surface, which head is connected to the shaft, wherein at least the shaft and/or the head comprises embedded reinforcing fibers, wherein at least one pre-formed recess is provided in the back surface of the shaft or the head, and wherein at least one weight holder is allocated into the at least one pre-formed recess, said weight holder having at least one releasable coupling, configured for releasable retaining an interchangeable weight.

The weight holder of the fiber reinforced composite field hockey stick according to the present invention allows to retain an interchangeable weight within the hockey stick that allows a player to decide on the weight of the stick. To this end it is conceivable that the interchangeable weight may be selected out of several varying different weights, so allowing the adaption of the weight of the stick. It is also possible that the present invention comprises at least one pre-formed recess in the back surface of both the shaft and the head of the stick. It is furthermore noted with respect to the terminology that the handle of a stick falls within the meaning of the wording shaft according to the present invention. Both terms may therefore be used throughout this application. In a similar way, the head of the stick may also be referred to as the hook, and hence may also these two terms may be interchangeable used throughout this application. It is conceivable that the shaft or handle comprises a grip portion. The grip portion of a stick may be made of various materials and have in cross section a more or less circular shape in order to be comfortable to hold. As the name suggest, the grip portion of the stick may be provided with material that increases the frictional resistance of the grip to better hold the stick. It is also common that said grip material enables partial absorption of shocks, which is especially beneficial when reinforcing fibers are used in the stick.

Generally, the grip portion is located at the extreme upper portion of the stick and may stretch for instance over 30 to 60 cm of said upper portion of the stick. The reinforcing fibers may preferably be located over the length and in the longitudinal direction of the shaft and/or the head.

The pre-formed recess may be provided with at least one weight holder for holding an interchangeable weight. By using a weight holder, the fibrous material used for at least partially forming the shaft and/or head is protected against damage on the interchangeable weight. To this end it is preferred that the weight holder substantially entirely/fully covers the interior of the pre-formed recess. Additionally, it is preferred that the weight is not protruding beyond the back surface of the stick.

This enables the weight holder to nest inside the pre-formed recess. The potential repetitive movement of inserting and removing an interchangeable weight will thus only interfere with the weight holder and not with the rest of the stick. It may however also be efficient in production of the field hockey stick according to the present invention. The weight holder may be produced as an individual part that is allocated in the pre-formed recess in a later stage of production. The weight holder may also be provided, either integrally or separately, with releasable couplings.

In an embodiment the shaft is provided with a plurality of pre-formed recesses, wherein at least one weight holder is allocated into at least one of the pre-formed recesses, preferably a weight holder is allocated into each of the pre-formed recess. As previously elaborated, an interchangeable weight may be selected from several varying weights, so enabling to select a preferred weight of the stick by either retaining heavier or lighter weights in the weight holders. By providing the stick with a plurality of pre-formed recesses, and preferably a weight holder allocated in each of the pre-formed recess, not only the weight variation of the stick may be larger, it also enables to vary the weight distribution (and/or the center of gravity) of the stick. In a non-limitative example three pre-formed recesses are provided in the shaft of the stick, and a weight holder is allocated in each of those three pre-formed recesses. If a player wishes to increase the weight of the stick, this can be realized as follows. If three different interchangeable weights are available, for example weighing 20, 30, and 50 grams, the order in which the weights are placed in the three different weight holders at least partially determines the location of the center of gravity of the stick. This example merely illustrative, and it is conceivable that different weights, and different amounts of recesses are used. Preferably, the pre-formed recesses are mutually spaced apart, for instance in equidistantly spaced apart. The one or more weight holders may be fastened/secured into a pre-formed recess with an adhesive. To allocate a weight holder securely into the pre-formed recess also other coupling methods may be used (or combined) such as a frictional coupling, tongue and groove joints, and other coupling methods. However, the use of an adhesive is preferred as forcing the weight holder into a recess may potentially damage the fibrous material. The same disadvantage holds for similar coupling methods such as the ones mentioned above. By using an adhesive, the present invention allows for a reliable coupling, wherein the reinforcing fibrous material in the hockey stick will not damage. This may significantly contribute to both the stiffness and durability of the hockey stick.

In a further embodiment of the present invention the reinforcing fibers follow the contours of the pre-formed recess, such that these reinforcing fibers continue uninterrupted along the pre-formed recess. It is conceivable that at least a part of the fibers, preferably all the fibers, are continuous fibers that are not interrupted by the pre-formed recess. This may for example be realized by using a mold during manufacturing of the stick, wherein the mold comprises at least one protrusion (in case of a positive mold) that corresponds to the shape of the recess to be formed during the molding of the stick.

A pre-formed recess may comprise a bottom surface and a side surface, the side surface preferably tapering inwardly as an inwardly tapering side surface provides multiple beneficial effects. First, it is conceivable that a tapering side surface acts as a guide for inserting the weight holder, which to this end may have side surfaces that are provided with a corresponding tapering. This enables a simple and correct placing of the weight holder in the pre-formed recess. A tapering side surface may also contribute to easily release a molded hockey stick form a mold. The tapering may be relatively small, wherein a tapered side surface encloses an angle with respect to the outer surface of the hockey stick between 91 and 120 degrees.

To enhance the quality of the hockey stick, the reinforcing fibers at least partially extend in the lateral direction of the shaft and/or the head. The fibers extend at least partially in the lateral direction of the shaft and/or head near (adjacent) a pre- formed recess. Preferably, the lateral direction of the fibers also includes an inwardly pointing directional component. This further contributes to the desired stiffness of the stick. When a plurality of, preferably spaced apart, pre-formed recesses are provided, the strength and/or stiffness of the stick may even positively be affected by the inclusion of the recesses during the molding process. This may be caused by the fact that the recesses are mutually spaced apart, and hence there 5 is not a single, large, recess which may locally lower the stiffness. Instead, due to the presence of the multiple pre-formed recesses the fibers are forced around those recesses, this may cause the fibers to increase the stiffness and/or strength in comparable way as an H-profile is stronger/stiffer than a single beam profile.

Atleast one pre-formed recess may be embodied as an elongated recess which may be oriented longitudinally in a direction substantially parallel to the shaft and/or the head of the hockey stick. In case a plurality of pre-formed recesses is provided, each of them may have identical dimensions as this allows the weights to be interchangeable over multiple pre-formed recesses.

Preferably, at least one pre-formed recess is provided on the back of the shaft and/or the head of the field hockey stick. The back of the stick may be contemplated as the non-ball-hitting surface of the stick. Allocating the recesses on the back surface is beneficial since it may be les obtrusive to the player. That way, the hockey play will be less likely to be hindered by the weight-filled recesses.

Although providing the recess on the back surface is preferred, it may be conceivable that one or more recesses may be provided somewhere along the edge of the stick, preferably at a location that usually not serves as a striking surface.

The shaft and/or the head may comprise embedded reinforcing fibers over the entire length, and the shaft and the head may be integrally connected. Preferably, at least part of the reinforcing fibers is chosen from the group consisting of carbon fibers, glass fibers, aramid fibers, high modulus polyester fibers, diols, vectrans and natural fibers. Said fibers may be infused with epoxy and/or resin to harden them, any resin or epoxy known in the art suitable for application in a stick and the aforementioned types of fibers may be used to this end. Preferably, at least a part of the fibers are long fibers, extending over a substantial length of the stick. It is also possible that the fibers are weaved, to achieve a higher overall strength of the stick. It is preferred that substantially the entire stick is formed out of the reinforced fibers. Where in this application the wording fibers, fibrous material, reinforced fibers, and the like are used, they all fall within the scope of protection, and refer to the fibers mentioned above. Moreover, it is also possible that a combination of various types of fibers is used.

Preferably, a weight holder is provided with at least two releasable couplings, configured for releasable retaining an interchangeable weight. To this end, the releasable couplings may be either an integral part of the weight holder or may be embodied as loose parts. With at least two releasable couplings, a secure connection between the interchangeable weight and the weight holder may be achieved. This will limit the chance of losing an interchangeable weight during a game or training. The releasable couplings may be identical, or they may be different. In case the releasable couplings are formed integrally with the weight holder, they may be processed in a single production step and there is no chance of losing the releasable couplings.

In a further embodiment the field hockey stick also comprises at least one interchangeable weight that is retained in a weight holder. Preferably, the surface of a weight retained in a recess is substantially flush with the back surface of the shaft and/or the head of the stick. By allowing the weight that is retained in a recess, of more in particular in the weight holder allocated therein, allows to provide for a more unobtrusive application. For example, when playing a backhand, the back surface of the stick will be relatively close to, or even in contact with, the playing field. Furthermore, a flush surface has the advantage that no annoying raised or recessed edges are present. This makes the solution according to the present invention user friendly. it is conceivable that the interchangeable weight is provided with at least one through hole/opening, and wherein the weight holder is provided with a protrusion, wherein preferably the through hole and protrusion are matching. This allows the interchangeable weight to be guided into the weight holder over the protrusion.

Preferably, the weight holder comprises two of said protrusions, and the interchangeable weight comprises two of said through holes. It is also possible that the protrusion and through hole may form at least a part of the releasable coupling.

In yet another embodiment of the hockey stick according to the present invention, various interchangeable weights are retainable in a weight holder. This may further contribute to the modularity of the stick according to the present invention. The interchangeable weights may have a plurality of different weights, ranging for instance from 5 grams to 500 grams, such as for example, but not limited to, a weight of 5 grams, 10 grams, 20 grams, 30 grams, 50 grams, 75 grams, 100 grams, 150 grams, 200 grams and 300 grams. Dependent of the base weight of the stick without the interchangeable weights retained therein, the player can decide as what a good total weight of his or her stick would be, if the total weight will be compliant to the rules. Also, since the stick may be provided with a plurality of recesses, the player may decide to distribute the different interchangeable weights such that the stick has a preferred weight distribution. This can be easily achieved after choosing the desired total weight. If for example a total weight increase of 110 grams is desired, and the stick comprises a total of four weight holders allocated in different pre-formed recesses, there is a plurality of ways to achieve this, each with a different weight distribution. For example, he or she may choose a single interchangeable weight of 100 grams, and another of 1 gram. But another option would be to pick one of 100 grams, and two of 5 grams. Thirdly, and not finally, another way would be to pick one weight of 10 grams, one of 20 grams, one of 30 grams, and one of 50 grams. Within this arsenal of options even more options are available, since the weights may be retained in a different order in the weight holders, causing the weight distribution to shift. It is also conceivable that at least one interchangeable weight is a mock weight. Said mock weight is preferably as light as possible. By retaining a mock weight in one of the weight holders, which preferably is flush with the back surface of the stick, allows the exterior surface to not have any recesses with respect to the back surface. Hence, does not suffer in terms of performance, especially on the backhand side.

At least one releasable coupling of the field hockey stick according to the present inventio may comprise a male portion and a female portion, one of them attached to the weight holder, the other attached to the interchangeable weight. Preferably, the male part of the releasable coupling is attached to the weight holder, more preferably said male part of the releasable coupling is formed in a protrusion of the weight holder. The female portion, that is preferably provided on, either directly or indirectly, the interchangeable weight, such that a coupling may be formed. The portion, male or female, that is attached to the interchangeable weight, may in fact be a separate component and the interchangeable weight may be configured to be locked to the locking portion of the weight holder by an external locking element.

Such locking element may be configured to connect to the locking portion of the weight holder, thereby retaining the interchangeable weight in the weight holder.

This may be beneficial since it allows for an easy change of the interchangeable weights, without causing damage to either the stick, the recess, the weight holder, or the interchangeable weight. In a preferred embodiment the releasable coupling connects to a bottom surface of the weight holder. More preferably, a part of the releasable coupling is integrally formed with the weight holder. To achieve a proper locking, a bayonet coupling may be used. Preferably, the female part is either attached, or integrally connected to, the weight holder. The female bayonet part may be a substantially cylindrically shaped protrusion, having two L-shaped slots.

The male portion of the bayonet coupling may be formed by a substantially cylindrically shaped part, having laterally extending radial pins, wherein said pins are configured to be received by the L-shaped slots. To further improve the bayonet mount, a spring may be present to keep the interchangeable weight in the locked position. To this end, the male portion of the bayonet lock is preferably a separate component, which locks the weight. It is however equally conceivable to have the inverse of the above-described solution, wherein in fact the weight holder is provided with a protrusion with laterally extending radial pins, and a separate female bayonet locking part which may be a cylinder that comprises an L-shaped recess provided therein configured for achieving at least a vertical locking together with the male portion. Additionally, a screw coupling may be used to achieve similar benefits, to achieve this, a protrusion of the weight holder may be provided with a threaded part, wherein an external bolt and/or nut is configured to co-act with said threaded part, and thereby retaining the interchangeable weight. Moreover, it is also possible a snap coupling is used. This may be possible by means of a tongue- and-groove coupling, wherein the tongue may be either provided on the weight or the weight holder.

The field hockey stick according to the invention may also be provided with one or more cover plates, which cover plates allow to cover a pre-formed recess with weight holder that is not filled with a weight. This allows also to leave a weight holder being unfilled with a weight without the disadvantage of a remaining opening in the stick. Using such one or more of such cover plates increases the setting range because now also a “0 weights” may be applied

The present invention is further related to an interchangeable weight for use in a field hockey stick according to any of the preceding claims. With respect to the interchangeable weight the same advantages may be realized as explained above, in relation to the fiber reinforced composite field hockey stick. The advantages as described above are hereby included by reference with respect to the interchangeable weight.

The present invention will hereinafter be further elucidated based on the following non-limitative drawings. Herein shows: - figure 1 a part of a fiber reinforces field hockey stick according to a first embodiment; and - figure 2 an enlarged view of a pre-formed recess according to a different embodiment.

Figure 1 shows a part of a fiber reinforced composite field hockey stick 1 according to a first embodiment. For illustrative purposes the stick 1 itself is merely shown in a schematical manner, the shape thereof may be different and is not limited to the depicted shape. The field hockey stick 1 comprises a shaft 2, and a head 3, wherein the head 3 is connected to the shaft 2. In this figure, merely the back surface 4 of the field hockey stick 1 is visible. In this embodiment the shaft 2 of the stick 1 is provided with three pre-formed recesses (not shown in this figure due to ilustrative purposes but shown in figure 2). Although the pre-formed recesses are not shown in this figure, a plurality of weight holders 6 are, which are to be allocated in the pre-formed recesses. In this non-limitative figure, the weight holders 6 are allocated substantially perpendicular to the length of the stick 1. The weight holders 6 are configured to receive an interchangeable weight 7. In this example, each of the weight holders 6 is provided with an interchangeable weight 7. However, it would also be possible to leave one of the weight holders 6 empty or provided it with a mock weight or cover plate. To retain the interchangeable weights 7 within the weight holder 7, a releasable coupling 8 allows to lock the weights 7 in the weight holders 6.

Figure 2 shows an enlarged view of a single pre-formed recess 5 in the stick 1. The pre-formed recess 5 that is depicted is provided on the back surface 4 of the stick 1. In this instance, the pre-formed recess 5 is substantially elongated, wherein the length direction of the recess 5 is substantially parallel to the length direction of the stick 1 itself.

Inside the pre-formed recess 5 the weight holder 6 is allocated.

The weight holder 6 is preferably adhered by means of an adhesive.

The adhesive may connect the interior surface, in particular the side surface 10 of the pre-formed recess 5, to the outer side surface 11 of the weight holder 6. As can be clearly seen in this figure, the weight holder 6 has an outer surface 11 that slightly tapers inwardly.

Said inwardly tapering portion of the weight holder 6, is substantially identical to the tapering of the side surface 10 of the pre-formed recess 5. This allows the weight holder 6 to be guided into the correct position.

The weight holder 6 is further provided with two protrusions 12 this particular embodiment.

These protrusions 12 co-act with the through holes 9 of the interchangeable weight 7. The protrusions 12 of the weight holder 6 also allow the interchangeable weight 7 to end up in the correct position.

Once the interchangeable weight 7 is in its correct position, it can be locked by means of releasable couplings 8. These couplings 8 are provided with recesses 13, which are L-shaped, and configured to co-act with either the interchangeable weight 7 and/or the weight holder 6 to realize at least a vertical locking.

Moreover, on the top side of releasable couplings 8, a second recess 14 is provided.

The second recess 14 is configured to rotate the releasable couplings 8, due to which rotation coupling and decoupling may be achieved.

To this end, radial pins (not shown) may enter the L-shaped recess 13, and when the radial pins reach the horizontal part of the L-shaped recess 13, a rotational movement of the releasable couplings 8 realized the locking.

Claims (17)

Conclusions 1. A fibre-reinforced composite field hockey stick, comprising: - a shaft, having a front surface and a rear surface, and - a head, having a front surface and a rear surface, which head is connected to the shaft, at least the shaft and/or the head comprises embedded reinforcing fibers, at least one preformed recess provided in the back surface of the shaft or head, and at least one weight holder disposed in the at least one preformed recess, said weight holder having at least one releasable coupling, configured to releasably hold an interchangeable weight. 2. Fibre-reinforced field hockey stick according to claim 1, characterized in that the shaft is provided with several preformed recesses, wherein at least one weight holder is arranged in at least one preformed recess, preferably a weight holder is arranged in each preformed recess. 3. Fibre-reinforced field hockey stick according to claim 1 or 2, characterized in that a weight holder is attached in a preformed recess with an adhesive. 4. Fibre-reinforced field hockey stick as claimed in any of the foregoing claims, characterized in that the reinforcement fibers follow the contours of the preformed recess, such that these reinforcement fibers run uninterrupted along the preformed recess. 5. Fibre-reinforced field hockey stick according to any one of the preceding claims, characterized in that a preformed recess comprises a bottom surface and a side surface, the side surface preferably tapering inwards. 6. Fibre-reinforced field hockey stick according to claim 5, characterized in that the reinforcing fibers extend at least partly in a lateral direction of the shaft and/or the head. A fibre-reinforced field hockey stick according to any one of the preceding claims, characterized in that at least one preformed recess is an elongated recess, said elongated recess being oriented longitudinally in a direction substantially parallel to the shaft and/or the head. A fibre-reinforced field hockey stick according to any one of the preceding claims, characterized in that at least one preformed recess is provided on the back surface of the shaft and/or the head of the fibre-reinforced field hockey stick. 9. Fibre-reinforced field hockey stick as claimed in any of the foregoing claims, characterized in that the shaft and/or the head comprise reinforcement fibers embedded over their entire length, and that the shaft and the head are integrally connected to each other. 10. Fibre-reinforced field hockey stick according to any one of the preceding claims, characterized in that at least part of the reinforcing fibers is selected from the group consisting of: carbon fibres, glass fibres, aramid fibres, high modulus polyester fibres, diols, vectrans and natural fibres. A fibre-reinforced field hockey stick according to any one of the preceding claims, characterized in that a weight holder has at least two releasable couplings configured to releasably hold an interchangeable weight. 12. Fibre-reinforced field hockey stick according to any one of the preceding claims, characterized in that the field hockey stick further comprises at least one replaceable weight, the replaceable weight being held in a weight holder. A fibre-reinforced field hockey stick according to claim 12, characterized in that the surface of a weight held in a preformed recess is substantially flush with the back surface of the shaft and/or head of the stick. 14. Fibre-reinforced field hockey stick according to any one of the preceding claims, characterized in that interchangeable weights of different masses can be held in a weight holder. 15. Fibre-reinforced field hockey stick according to any one of the preceding claims, characterized in that at least one releasable coupling comprises a male part and a female part, one of which is attached to the weight holder and the other is attached to the replaceable weight. 16. Fibre-reinforced field hockey stick as claimed in any of the foregoing claims, characterized in that the releasable coupling is connected to a bottom surface of the weight holder. An interchangeable weight for use in a field hockey stick according to any one of the preceding claims.