HOCKEY STICK WITH PLASTIC WEAR STRIP

Abstract

The hockey stick has a plastic wear strip along the bottom edge of the blade of the stick. Preferably the wear strip is of polyurethane having a flexural modulus in the range of 300 to 550 MPa at room temperature and 1200 to 1400 MPa at −30 degrees Celsius. In a goaltender's stick having a foam core, the wear strip is inserted in a mold and integrally formed with the core of the stick. The wear strip preferably is manufactured via a RIM process, then the core of the stick is molded with the wear strip and stick shaft in position, and then conventional finishing steps are applied, with fiberglass overlays for example.

Description

BACKGROUND OF THE INVENTION

This invention relates to the sport of hockey, and in particular to hockey sticks. The invention is especially applicable to goalie sticks, i.e. the sticks used by hockey goaltenders, but it is conceivable that the invention could be adapted to hockey sticks generally.

Hockey sticks, including goalie sticks, are subject to a good deal of abuse in recreational use, practices and games. Furthermore, modern hockey sticks are significantly more expensive than traditional wooden sticks, due to the materials used and the amount of labor involved in their manufacture. This is particularly the case with goalie sticks, due to the smaller volumes produced and due to their somewhat more complex overall structure.

Normal hockey sticks tend to break mostly during slap shots, from impact with the hockey puck or the ice surface or both. They may also break from other impacts, for example with the hockey boards, goalposts, or from deliberate breakage by frustrated players. Goalie sticks are less prone to breakage from impact, primarily because impacts are less frequent. However, they can also be broken deliberately by a frustrated goaltender. Otherwise, the primary cause of deterioration of the structural integrity of the stick is wear of the blade of the stick due to friction between the bottom of the stick and the ice, in combination with constant puck impacts and force applied by the goaltender towards the surface of the ice. Wear from these factors becomes a significant factor in determining the life of the stick. Delamination or other problems may arise. When a stick blade is starting to delaminate, the quality of puck deflection is not consistent and cannot be properly controlled by the goaltender. The longer period of time that the blade remains intact, the more consistent its characteristics are, and the longer players are able to use it with good results.

In view of the preceding, it would therefore be advantageous to have a goalie stick design which extends the life of the stick for as long as possible, by reducing wear of the blade. Such a design might also be readily adaptable to normal hockey sticks, to potentially extend their life as well.

BRIEF SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a hockey stick with improved durability. For convenience, generally only a goalie stick will be described herein, but as mentioned above, the invention conceivably could be adapted to other hockey sticks.

In the invention, a plastic wear strip is embedded along a bottom edge of the blade. Preferably, the plastic strip is a somewhat flexible polyurethane strip, and extends a substantial distance along the bottom of the blade. More preferably, the plastic strip extends substantially the full length of the hockey stick blade, from heel to toe.

Preferably, the wear strip is somewhat flexible (at least prior to installation), durable, abrasion resistant, and capable of absorbing energy when impacted. Preferably, in the case of a foam core stick, the wear strip has chemical affinity, i.e. it is chemically similar to the core material of the stick. Its contribution to the rebound characteristics of the stick ideally should be neutral.

In a preferred embodiment, the wear strip is manufactured in a two-component polyurethane reaction injection molding (RIM) system, and has a flexural modulus of preferably about 500 MPa at room temperature and preferably about 1300 MPa at −30 degrees Celsius.

From testing, this wear strip appears to have the ability to absorb impact forces and therefore appears to prolong stick life by insulating the foam core material from those impact forces. However, it is conceivable that other urethane materials, whether using the RIM process or injection molding, could be acceptable for use. That could be determined by routine testing and experimentation.

Further details of the invention will be described or will become apparent in the course of the following detailed description and drawings of specific embodiments of the invention, presented as examples only.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the invention will now be described, by way of example only, with reference to the attached drawings, in which:

FIG. 1 is a perspective view of a preferred embodiment of a hockey goaltender's stick, with a wear strip along the bottom edge of the blade and part of the heel;

FIG. 2 is a side view of the wear strip;

FIG. 3 is a cross-section of the wear strip at A-A of FIG. 2;

FIG. 4 is a similar cross-section, showing an alternative configuration for the web portion of the wear strip; and

FIG. 5 is another similar cross-section, showing another alternative configuration for the web portion of the wear strip.

DETAILED DESCRIPTION OF THE INVENTION

Structure

A preferred embodiment of the invention is illustrated in FIG. 1, which shows a goalie stick 1. The stick has a core 2 and a shaft 3 which is embedded in the core as part of the core molding process, as described in more detail below. The goalie stick has a paddle portion 4, and a blade 5, both of which are integral parts of the core 2. The blade has a heel 6 and a toe 7. In the case of a regular hockey stick, there is of course no paddle; the shaft extends all the way down to the blade.

Embedded along the bottom edge of the blade 5, preferably but not necessarily running its full length from the heel to the toe, is a plastic wear strip 8 according to the invention, as shown in FIGS. 1-3. The wear strip is shaped to follow the shape of the bottom of the blade, and preferably an upwardly-rising portion of the heel. The wear strip is made of a somewhat flexible and preferably somewhat resilient plastic, preferably polyurethane. Dimensions shown in FIGS. 2-3 are typical, but obviously could be varied.

The flexibility of the wear strip 8 is sufficient at least to faciliate its positioning in the mold and its use with somewhat different blade shapes, since there can be a wide variety of shapes. The flexibility also allows for the blade to be curved, without any undue or permanent stress which would negatively impact on the stick's usable life.

The wear strip preferably also has some resilience, which cushions impacts slightly, i.e. absorbs energy, thus reducing the transfer of energy to the main body of the blade 5 and core 2. This cushioning effect extends the life of the stick more than if the strip was a rigid plastic piece.

In a preferred embodiment, the core 2 is a polyurethane foam and fiberglass structure, as is presently conventional, having a flexural modulus of 300-550 MPa at room temperature. The wear strip material should adhere suitably to the foam with a strong permanent bond, and should accept being bonded to the typical fiberglass outer reinforcements of the stick.

As seen best in FIG. 3, the wear strip 8 preferably is generally in the shape of an inverted “T”, such that its bottom portion 9 covers the width (i.e. thickness) of the bottom edge of the blade, and its upwardly-extending web portion 10 extends into the blade core and is anchored therein.

Preferably, the web portion 10 has a number of holes 11 through it, so that the foam expands into those holes for more secure anchoring of the web portion and wear strip generally. Instead of holes, the web portion could be provided with other means for anchoring, such as by providing ribs 12 and/or slots 13, as seen in FIG. 4, or zig-zag shapes 14 as seen in FIG. 5, or protruding pins (not shown), or any other suitable means.

Wear Strip Material

In selecting the material for the wear strip 8, it was desired to have a material which would be compatible with the core of the blade, to adhere to it so as to form an integral and strong unit, enhance the final quality of the core, and increase the durability of the total stick by protecting the bottom part of the core from abrasion against the ice, without unduly affecting rebound characteristics of the core. It was also desired to have a material which would be technologically easy to produce, by molding for example, instead of machining from a plastic sheet. Ideally the material would have similar mechanical characteristics to the core and be chemically compatible with the core.

As mentioned in the summary above, in a preferred embodiment, the wear strip is manufactured in a two-component polyurethane reaction injection molding (RIM) system, and has a flexural modulus of preferably about 500 MPa at room temperature and preferably about 1300 MPa at −30 degrees Celsius. A RIM system is preferred due to the lower mold and material costs compared to injection molding. However, a thermoplastic polyurethane material could instead be selected and injection molded to produce the wear strip.

In this RIM process, two components are delivered separately to a mixing head by high pressure pumps and are mixed under very high pressure. The resulting mixture is injected from the head into a closed mold, where the chemical reaction between the components forms rigid thermoplastic polyurethane. The result is a product which has a flexural modulus less than most other polymers (such as polyethylene, polypropylene, Nylon, etc.), but which is strong enough to permit significant part deformation without damage. The RIM process also is technologically suitable for processing, allowing faster demolding times (between 40 seconds and 2 minutes for example), and providing good flow characteristics to fill the mold quickly and easily to produce a high quality part without air bubbles or distortion. The resulting product has to pass low temperature flexural modulus testing and should not be brittle enough to break at temperatures as low as −30 Celsius or even −50 Celsius.

The polyurethane system for the wear strip 8 was chosen to be as close as possible to the existing core materials while still achieving the goals of the invention. The selected polyurethane system produces a wear strip with flexural modulus generally in the same range as the core, and even more importantly, does not break at −30 Celsius or even lower. In testing, the flexural modulus at −30 Celsius was in the range of 1,200 to 1,400 MPa, and the wear strip did not break. The material has a hard and durable surface with a Shore A durometer reading of preferably but not necessarily at least 80, and better still preferably 90 to 95, with also high abrasion resistance.

Process

In manufacturing the stick as a whole, there are three main steps. The first step is manufacturing the wear strip, preferably but not necessarily via the RIM process as described above. The second step is molding the core of the stick, with the wear strip 8 and shaft 3 embedded in it. The third step is finishing the stick. The second and third steps are essentially conventional, with the exception that the wear strip is positioned in the mold for the core, so as to be captured along the bottom edge of what becomes the blade of the stick.

In the core molding process, typically a fiberglass mat is laid into the cavity of a clamshell mold. The wear strip 8 of the invention is then positioned along the edge of the cavity corresponding to the bottom of the blade 5. The shaft 3 is also positioned so that its lower end will be captured by the core material. The shaft could be wood, laminated plywood, a solid core with veneer, a composite material, or any other suitable material. The composition of the shaft is not part of the invention.

Then typically a spacer is placed in the mold, and the spacer is overlaid with another fiberglass mat. The fiberglass mats constitute the outer surfaces of the core, and the spacer holds them in their proper positions prior to injection of the foam.

The mold is closed, a dispensing head is positioned over the mold inlet, and the dispenser is activated to introduce a conventional two-component polyurethane foam resin system into the mold. The foam fills the mold cavity, and also surrounds the web portion 10 of the wear strip 8, to anchor it in place. After curing, the mold is opened, the core 2 is demolded (with the wear strip 8 and shaft 3 captured), flash is trimmed off and the part is inspected for defects.

It should be understood that these details of the molding process, except for the insertion of the wear strip, are generally conventional and not part of the invention.

Once the reaction is complete and the mold is opened, the result is a completed core of foam overlaid with fiberglass, with the wear strip secured along the bottom edge of the blade, and the hockey stick shaft extending out the upper end of the core. The stick is now ready for finishing operations. These finishing operations are conventional, and therefore will not be described in detail, but may include removal of excess flash, sanding, applying additional layers of fiberglass or carbon fiber, bending the blade to a desired finished shape, and applying finish coats of paint or urethane coat, along with appropriate branding or other graphics.

CONCLUSION

It will be evident to those knowledgeable in the field of the invention that many variations on the examples described above are conceivable within the scope of the invention. It should therefore be understood that the claims which define the invention are not restricted to the specific examples described above.

The hockey stick may not necessarily have a polyurethane foam core. For example, it could be made of a number of other thermoplastic foams, with the wear strip 8 having any complementary shape and being positioned along the bottom edge, held in place by a fiberglass wrap during the manufacturing process, or by an adhesive.

Further variations may be apparent or become apparent to those knowledgeable in the field of the invention, within the scope of the invention as defined by the claims which follow.

Claims

1. A hockey stick, having a blade with a toe end and a heel end, wherein a plastic wear strip is positioned along a bottom edge of the blade.

2. A hockey stick as in claim 1, where the plastic wear strip is of a somewhat flexible and somewhat resilient polyurethane.

3. A hockey stick as in claim 2, where the polyurethane has a flexural modulus in the range of 300 to 550 MPa at room temperature and 1200 to 1400 MPa at −30 degrees Celsius.

4. A hockey stick as in claim 1, wherein the wear strip is embedded in bottom of the blade.

5. A hockey stick as in claim 4, where the plastic wear strip is of a somewhat flexible and somewhat resilient polyurethane.

6. A hockey stick as in claim 4, where the polyurethane has a flexural modulus in the range of 300 to 550 MPa at room temperature and 1200 to 1400 MPa at −30 degrees Celsius.

7. A hockey stick as in claim 1, configured as a goaltender's stick and having a polyurethane foam core comprising said blade, wherein the wear strip is molded integrally with said foam core so as to be captured by said foam core.

8. A hockey stick as in claim 7, wherein said wear strip has a projecting central web portion, and wherein said web portion is captured by said foam core to hold said wear strip in position.

9. A hockey stick as in claim 8, where the plastic wear strip is of a somewhat flexible and somewhat resilient polyurethane.

10. A hockey stick as in claim 9, where the polyurethane has a flexural modulus in the range of 300 to 550 MPa at room temperature and 1200 to 1400 MPa at −30 degrees Celsius.