TECHNICAL FIELD

This invention relates to skate boots, and particularly to a skate boot having a composite material sole, of a resin reinforced with fibers. Although primarily intended for ice skates, the skate boot could also be used for in-line skates or roller skates.

BACKGROUND ART

In conventional skate boots, the material used for the sole or outsole of the boot is TPR (thermoplastic rubber). Many years of tradition and gradual evolution have led to this becoming the almost universal choice of skate boot manufacturers. The sole is designed to provide an interface between the sewn boot and the ice skate blade holder or in-line skate chassis. It provides a structure to which the materials of the upper can be attached. It does not provide a great deal of structural support, and is in fact soft and flexible. In view of the general suitability of TPR, there has been little incentive to innovate. It has hitherto been thought that TPR was clearly the best material, perhaps partially because it is vastly better than materials used in older skate boots.

However, TPR does have the disadvantage of being somewhat energy absorbent or "spongy". In ice skating of hockey, especially at the professional or serious amateur level, this absorbency is undesirable, since it softens the "feel" of the ice, and reduces the efficiency of energy transfer from the skater's legs and feet through the boot to the blade and ice surface. The TPR poses a problem when attempting to control the energy transmitted from the musculature during the skating stride, and in feeling the ground reaction forces for balance and skating control.

The inventor has recognized that a thinner, less spongy sole would be desirable, to improve the energy transfer and to provide the skater with better ice contact and control, particularly during tight turns and the like.

Metal soles were considered, but have been recognized as being undesirable due to being too cold for ice skates. Furthermore, once deformed, a metal sole may remain deformed, rather than springing back to its original shape.

DISCLOSURE OF INVENTION

It is an object of the invention to provide a boot with a thinner and lighter sole than had hitherto been thought possible, without undesirable sacrifices in rigidity or stiffness.

Accordingly, in the invention, a thin, strong composite material is used for the sole of the skate boot. The sole is a thin layer of composite material, namely a mix of resin and reinforcing fibers, which provides a high flex modulus and creates a high stiffness to weight ratio. Thermoset or thermoplastic resins may be used, with glass, carbon, Kevlar (trademark) or other suitable fibers. Further features of the invention will be described or will become apparent in the course of the following detailed description.

BRIEF DESCRIPTION OF DRAWINGS

In order that the invention may be more clearly understood, the preferred embodiment thereof will now be described in detail by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of an ice skate boot of the preferred embodiment;

Fig. 2 is a side view of the skate boot, cut open to show its construction in the heel area; Fig. 3 is a perspective view of the skate boot, cut open in the toe area;

Fig. 4 is a front sectional view, exploded to show the various components;

Fig. 5 is a front sectional view similar to Fig. 6, but showing the various components rivetted together;

Fig. 6 is perspective view of the sole of the skate boot; and Fig. 7 is a plan view of the sole.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to the drawings, the invention will now be described in greater detail. The following description refers to an ice skate boot, but the same principles will apply to boots for in-line skates or roller skates.

The skate has two main components, namely the boot 1 which includes a sole 2, and the blade holder 3 which includes a blade or runner 4.

The blade holder is fastened to the boot in conventional fashion, via rivets 5.

As can be seen best in Figs. 2, 3, 4 and 5, the boot includes an upper 6 which has a curled-under portion 7 which is positioned above the sole

2. A plastic platform 8 is then positioned above the curled-under portion and the sole. On top of the plastic platform is a thin foam liner 9. The rivets 5 pass through the blade holder, the sole, the curled-under portion of the upper, the plastic platform, and the foam liner.

Figs. 6 and 7 show the preferred embodiment of the sole 2 of the present invention. The sole is a thin layer of composite material, molded to the shape as illustrated, with raised rib-like central contours 10.

The preferred composite material is a bi-directional mix of acrylic thermoplastic resin, glass and carbon fibers, such as the Novotek HW-5050

(trademark) material supplied by BioMechanical Composites (a division of

Medical Materials Corporation), of Camarillo, California, U.S.A.. A specification sheet is annexed hereto as Appendix A.

This material provides moderate stiffness, strength and durability with balanced directionality. It has cross-woven upper and lower facesheets of carbon and glass fibers, with a variable thickness core. In the preferred embodiment, the thickness of the overall sheet is 1 .4 mm. The material

decreases the overall weight of the skate by greater than 100 gm from about 1000 gm.

Obviously, the thickness could be varied, as could the material itself. Composite materials of resin and fibers, other than the Novotek material, certainly could be used. In general, thermoset resins such as polyester resin or epoxy resin, or thermoplastic resins such as polyamides (e.g. Nylon 6, Nylon 6- 6, Nylon 12, Nylon 1 1 ), acrylics, ABS, polypropylene, polyethylene, etc., could be used. The fibers are encapsulated in the resin in order to increase the flex modulus or stiffness of the sole. The orientation of the fibers and the percentage of fiber content versus resin content will dictate the final rigidity. The fiber can be in short lengths oriented randomly in the resin, or there can be longer strands, either unidirectionally oriented in the resin, or layered or woven to create a bi-directional structure.

Obviously, not all combinations of resins, fibers, orientations, lengths and percentages will be suitable. Suitable parameters must be selected through routine experimentation, to achieve the desired light weight and degree of stiffness.

In the preferred manufacturing process using the Novotek material or other thermoplastics, the material is first die-cut to the desired outer shape, then heated to facilitate molding, and then molded to its final, contoured shape. The manufacture of the overall boot then continues according to conventional practices. For example, the material is bonded to the curled-under portion of the boot upper via a suitable adhesive. The plastic platform and the foam liner are then inserted, and the rivets are installed in conventional fashion. As examples of alternative processes, hand lay up, compression molding, resin transfer molding or reaction injection molding could be used for thermoset resins. For thermoplastic resins, heat forming, vacuum forming, or injection molding could be used. The invention is not limited to use with these manufacturing processes only, but could conceivably be used in other manufacturing or assembly processes, known or as yet unknown.

Although the composite material is much thinner than soles in the prior art, and is not particularly rigid by itself, the result of the overall assembly is a skate boot which is surprisingly rigid in the sole area, which provides excellent force transfer from the skater's foot to the ice or other surface, and which is somewhat lighter than conventional skates.

It will be appreciated that the above description relates to the preferred embodiment by way of example only. Certain variations on the invention will be obvious to those knowledgeable in the field, and such obvious variations are within the scope of the invention as claimed, whether or not expressly described herein.

The above description relates to ice skates, but it should be clear that the invention could be applied to in-line skates or conventional roller skates as well. Instead of rivetting an ice skate blade holder to the boot, a wheel carriage could be attached.

INDUSTRIAL APPLICABILITY

The invention provides a skate boot with a sole which is quite rigid, yet light in weight.

APPENDIX A

NOVETEK™ HW-5050

Novetek HW-5050 uses a 50%/50% mix of carbon and glass fibers in two directions. It is suitable for applications that require modest stiffness, strength, and durability with balanced directionality compared to other Novetek alternatives.

COMPOSITION

Fiber Alternating woven carbon and glass fibers in both 0° and 90° orientation

Resin Acrylic

PHYSICAL CHARACTERISTICS

* Thickness 0.35" - .105" (1 .0mm- 2.5mm) available

* Weight .028 - .081 oz/in ² (.123 - .356 gm/cm ² )

* Surface Smooth. Transparent to fibers

* Size Cut to customer specifications, minimum 25 in ² , maximum 200 in ² (minimum 160 cm ² , maximum 1290 cm ² ) from sheet of 48" x 36" (122 x 91 cm).

PROCESS

Cutting Use steel rule die, forged die, hard tooling, shear or saw

Forming Heat to 350-390°F (175-200°C). Place under 5-10 psi (35-70 KPa) for about 1 5 seconds

Finishing Use general purpose grinding and polishing wheels on edge if required

Attachment Chemical, adhesive, or mechanical attachment to other materials/devices

Detailed instructions, consultation, and technical support concerning specific processing requirements are available upon request.

NOVETEK™ HW-5050 MATERIAL PROPERTIES

Thickness - inches (mm)

.035 0.45 .055 .065 .075 .085 .105

(.89) (1.14) (1.40) (1.65) (1.91) (2.16) (2.67)

Areal Density oz/in ² .028 .036 .043 .051 .059 .066 .081 gm/cm ² .123 .158 .189 .224 .260 .290 .356

Tensile Load

(ASTM D638) lb ^* 1160 1190 1215 1245 1275 1305 1365

N 160 5290 5400 5540 5670 5800 6070

Tensile Strength

(ASTM D638) lb/in ² 33100 26400 22100 19100 17000 15400 13200

KPax 10 ^"5 2.28 1.82 1.52 1.32 1.17 1.06 .91

Tensile Modulus

(ASTM D638) lb/in ² x 10 ^"5 2.6 2.4 2.2 2.0 1.8 1.6 1.2

KPa x 1 ⁷ 1.79 1.65 1.2 1.38 1.24 1.10 .83

•Flexural Rigidity lb-in ² " 12 23 40 62 88 118 184

N-cm ² 344 660 1148 1780 2325 3387 5280

Flexural Strength

(ASTM D790) lb/in ² x 10 ^"6 73700 63400 57200 53000 50000 47800 44000

KPax 10 ^"5 5.08 4.37 3.94 3.65 3.45 3.30 3.03

».e\

SUBSTITUTE SHEET (RULE 2o

Flexural Modulus

(ASTM D790) lb/in ² x 10 ^"6 3.3 3.1 2.9 2.7 2.5 2.3 1.9

KPa x 10- ⁷ 2.28 2.14 2.00 1.86 1.72 1.59 1.31

Shear Strength

(ASTM D2344) lb/in ² 4840 5000 5175 5340 5525 5650 6000

KPa x 10 ^"4 3.33 3.45 3.57 3.68 3.80 3.78 4.13

Flexural Fatigue

Strength at 1 x

10 ⁶ cycles

ASTM D790,

Method 1 lb/in ² 33100 28500 25800 23900 22500 21500 19800

KPa x 10- ⁵ 2.28 1 .96 1 .78 1 .65 1 .55 1 .48 1 .37

Izod Impact

(ASTM D256) ft-lb/in 5.0 5.0 5.0 5.0 5.0 5.0 5.0

J/cm ² 2.7 2.7 2.7 2.7 2.7 2.7 2.7

Creep

Resistance at

70% Ultimate,

120°F, 120 hr.

(ASTM D2990) in/in x 10 ^'3 7.2 7.2 7.2 7.2 7.2 7.2 7.2 cm/cm x 10 ³ 7.2 7.2 7.2 7.2 7.2 7.2 7.2

Heat Distortion

Temp.

°F 220 220 220 220 220 220 220

°C 105 105 105 105 105 105 105

* Per unit width.

* *Based upon product of effective elastic modulus and moment of inertia.

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