Information
-
Patent Grant
-
6422577
-
Patent Number
6,422,577
-
Date Filed
Tuesday, November 24, 199826 years ago
-
Date Issued
Tuesday, July 23, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Johnson; Brian L.
- Phan; Hau
Agents
- Christensen O'Connor Johnson Kindness PLLC
-
CPC
-
US Classifications
Field of Search
US
- 280 1122
- 280 1127
- 280 1117
- 280 1119
- 280 11221
- 280 1128
- 280 11225
- 280 11231
-
International Classifications
-
Abstract
A skate frame (20) for an in-line skate (18) having a shoe portion (22) and a plurality of wheels (24) capable of traversing a surface. The skate frame includes an elongate structural member comprised of a structural material having a first average density. The structural member having first and second sidewalls (62 and 68), each having an upper end and a lower end. The structural member also includes a shoe mounting portion (50) spanning between at least a portion of the upper ends of the sidewalls. The first and second sidewalls having a wheel, load introduction portion (58), wherein loads associated with the wheels are transferred to the structural member. The shoe mounting portion having a shoe load introduction portion, wherein loads associated with the shoe portion are transferred to the structural member. The skate frame also includes core material (64) disposed within at least one of the first and second sidewalls or within the shoe mounting portion. The core material being sealed within the sidewalls and/or the shoe mounting portion by the structural material or a filler material. The core material is absent from at least the wheel and shoe load introduction portions.
Description
FIELD OF THE INVENTION
The present invention relates generally to skates and, in particular, to a skate frame having a core of lightweight material to increase structural strength-to-weight and stiffness-to-weight ratio of the frame.
BACKGROUND OF THE INVENTION
In-line roller skates generally include an upper shoe portion having a base secured to a frame that carries a plurality of longitudinally aligned wheels. The upper shoe portion provides the support for the skater's foot, while the frame attaches the wheels to the upper shoe portion. Because in-line skates are designed to accommodate a variety of skating styles, including high-performance competitions, it is desirable for such skate frames to be lightweight, stiff, and strong. Skate frames may be constructed from a variety of materials, including aluminum, injection molded plastic and composites. Although aluminum skate frames are structurally strong and stiff, they are expensive. Skate frames constructed from an injection molded plastic are often reinforced with short, discontinuous fibers. Although such skate frames are lower in cost than aluminum frames, they lack the specific strength and stiffness performance characteristics associated with continuous fiber-reinforced composite frames.
Currently, fibers of glass or carbon are preferred to reinforce composite frames. Glass reinforced composite skate frames are both structurally stiff and strong, but they are heavier than composite frames reinforced with carbon fibers. Although carbon fiber reinforced skate frames are lightweight, strong, and stiff, they are expensive.
Frames constructed from composites reinforced with glass, carbon fibers or other high performance fibers may be improved by sandwiching a core material between face sheets or skins of reinforced composite material. The core is a lighter, less expensive material with moderate structural properties in terms of strength and stiffness.
Prior in-line skate frames having a core construction include inverted U-shaped skate frames having a polymer core bonded within the concave portion of the skate frame. In such skate frames, the core is positioned between the frame's arcuate portion and the wheels. Although such skate frames provide increased structural stiffness, the core is subjected to accelerated wear and damage because it is exposed directly to the wheels and road debris. Therefore, such a skate frame may have a shortened useful life.
Other attempts of providing an in-line skate frame with a core include inverted U-shaped skate frames with core material sandwiched between two composite face sheets. In this type of frame, the core extends from below the wheel attachment points upwardly and across the upper surface of the frame. The wheels and shoe portion of the skate are attached to the frame by drilling or molding their respective attachment points through the sandwich construction, thereby subjecting the core material directly to the loads of both the wheel axle and shoe portion attachment bolts. This construction is undesirable because the core material is in direct contact with the wheel and shoe attachment hardware and, therefore, is susceptible to breakage.
Still other attempts of providing in-line skate frames with a core have included a core inserted within the junction between the sole of the shoe portion and the skate frame. Such skate frames have a flange extending laterally from both sides of the upper end of the skate frame, such that the lateral and medial sides of the upper surface span outwardly to cup the sole of the shoe portion therein. The interior of the flange portion is filled with a core material to absorb a portion of the loads associated with traversing a surface. The location of the flanges relative to the frame is custom made to accommodate a particular skater's foot and shoe width. Because the flange portion is sized to cup a specific shoe width, there is limited adjustment of the location of the shoe portion relative to the frame. Therefore, such a skate frame is not very robust in accommodating different skating styles, even for the skater for whom the skate was custom made. Moreover, because the skate is custom made and designed for a particular skater, it is expensive to manufacture. Thus, there exists a need for a composite in-line skate frame having a lightweight core that not only maintains the frame's strength and stiffness, but also is economical to manufacture, and meets the performance expectations, of a skater.
SUMMARY OF THE INVENTION
The present invention provides both a skate frame for an in-line skate having an increased structural strength-to-weight ratio, and a method of constructing such a frame. The in-line skate has a shoe portion and a plurality of longitudinally aligned wheels capable of traversing a surface. The skate frame includes first and second sidewalls and a shoe mounting portion. Preferably, the sidewalls and shoe mounting portion include skins constructed from a material having a first average density. Each of the sidewalls have an upper end and a lower end. The lower ends of the sidewalls include wheel load introduction portions, wherein loads associated with the wheels are transferred to the sidewalls. The upper ends of the sidewalls are held in spaced parallel disposition by the shoe mounting portion spanning therebetween. The shoe mounting portion includes a shoe load introduction portion, wherein loads associated with the shoe portion are transferred to the shoe mounting portion. The skate frame also includes core material disposed within at least the first and second sidewalls, or within the shoe mounting portion. The core material is removed from at least the wheel and shoe load introduction portions.
In an aspect of a skate frame constructed in accordance with the present invention, the core material has a second average density that is less than the material density of the skins of both the sidewalls and shoe mounting portion by a predetermined amount and has predetermined structural properties. The core material occupies a volume within the skate frame to provide the skate frame with an increased structural strength-to-weight ratio.
In an aspect of the first preferred embodiment of the present invention, the core material is positioned within sidewalls. The core material is chosen from a group of materials that includes both reinforced and unreinforced polymers and natural materials.
In another aspect of the first preferred embodiment of the present invention, the skate frame also includes a plug of filler material disposed between the core material and the load introduction portions to absorb at least a portion of the loads associated with the wheels and shoe portion.
In yet another aspect of the present invention, the core material defines a varying height along a longitudinal axis extending between the ends of the skate frame.
In an alternate embodiment of the present invention, core material is disposed within the shoe mounting portion.
In yet another alternate embodiment of the present invention, core material is disposed within both the first and second sidewalls and the shoe mounting portion.
A method of constructing a skate frame for an in-line skate is also provided. The method includes the steps of forming a U-shaped first skin and positioning core material at a predetermined location on the first skin. The method further includes the step of forming a U-shaped second skin over the first skin, such that the core material is positioned and sealed between the first and second skins. A plug of filler material is disposed between the first and second skins to absorb at least a portion of the loads associated with at least the wheels or shoe portion of the skate. Finally, the method includes the step of curing the frame.
The skate frame of the present invention provides several advantages over skate frames currently available in the art. The skate frame of the present invention is lighter than solid composite or aluminum frames because a lightweight core material occupies a substantial volume within the frame. Also, because the core material is lightweight and provides a distance of separation between the skins of the sidewall, the strength-to-weight ratio of the frame is increased. Further, because the skate frame utilizes a core material that is less expensive than the reinforced composite material it replaces, it is more cost efficient than skate frames having an all composite construction. Finally, because the core material is removed from the load introduction points associated with the wheels and shoe portion, the skate frame has a longer useful life than skate frames having a core that is in direct contact with the load introduction points. Thus, a skate frame constructed in accordance with the present invention has an increased strength-to-weight ratio and is less expensive than those currently available in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing aspects and many of the attendant advantages of this invention will become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
FIG. 1
is an environmental view of an in-line skate frame constructed in accordance with the present invention having a portion of the skate frame cut away to show the inner skin, core material, filler material and outer skin;
FIG. 2
is a cross-sectional end view through an in-line skate frame constructed in accordance with the present invention showing the core material disposed between the inner and outer skins of the sidewalls and a plug of filler material disposed around the wheel attachment bores;
FIG. 3
is a cross-sectional end view of an alternate embodiment of an in-line skate frame constructed in accordance with the present invention showing the core material disposed between the inner and outer skins of the sidewalls;
FIG. 4
is a cross-sectional side view through a second alternate embodiment of an in-line skate frame constructed in accordance with the present invention showing core material disposed within the shoe mounting portion of the skate frame;
FIG. 5
is a cross-sectional end view of the second alternate embodiment of an in-line skate frame constructed in accordance with the present invention taken through Section
5
ā
5
of
FIG. 4
showing core material disposed within the shoe mounting portion of the skate frame;
FIG. 6
is a cross-sectional end view of a third alternate embodiment of an in-line skate frame constructed in accordance with the present invention showing core material disposed between the inner and outer skins of both the sidewalls and shoe mounting portion of the skate frame;
FIG. 7
is a cross-sectional end view of a fourth alternate embodiment of an in-line skate frame constructed in accordance with the present invention showing a three piece frame and core material disposed within the sidewalls of the frame;
FIG. 8
is a cross-sectional end view of a fifth alternate embodiment of a two piece in-line skate frame constructed in accordance with the present invention showing core material disposed within the sidewalls of the skate frame; and
FIG. 9
is a cross-sectional end view through an in-line skate frame constructed in accordance with the present invention showing the core material disposed between the inner and outer skins of the sidewalls, a plug of filter material disposed around the wheel attachment bores, and a decorative sheet disposed on the outer skin.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1
illustrates a preferred embodiment of an in-line skate
18
having a skate frame
20
constructed in accordance with the present invention. The skate frame
20
is shown attached to a shoe portion
22
and a bearing member in the form of a plurality of wheels
24
.
The shoe portion
22
has an upper portion
30
and a base
32
. The upper shoe portion
30
is preferably constructed from a flexible and durable natural or man-made material, such as leather, nylon fabric, or canvas. The upper shoe portion
30
also includes a conventional vamp
40
and vamp closure, including a lace
42
, extending along the top of the foot from the toe area of the foot to the base of the shin of the skater. Preferably, the upper shoe portion
30
is fixedly attached to the base
32
by being secured beneath a last board (not shown) by means well-known in the art, such as adhesive, riveting, or stitching. Alternatively, any skate footwear may be used with frame of present invention.
The base
32
is constructed in a manner well-known in the art from a resilient composite polymeric or natural material. The base
32
includes a toe end
34
, a heel end
36
and a toe cap
44
. Suitable materials for the base
32
includes semi-rigid thermoplastic or thermosetting resins, which may be reinforced with structural fibers, such as carbon reinforced epoxy, or other materials, such as leather, wood, or metal. The toe cap
44
surrounds the toe end of the upper shoe portion
30
and is suitably bonded to the base
32
. Alternatively, the toe cap
44
may not be used or may be formed of a different material from the rest of the base
32
, such as rubber. Because the upper shoe portion
30
is preferably constructed from nylon or other flexible, natural, or man-made materials, the function of the toe cap
44
is to protect the toe end of the upper shoe portion
30
from impact, wear, and water. The toe cap
44
also extends around the lateral and medial sides of the toe end of the upper shoe portion
30
to provide additional support to the foot of the skater.
Referring to
FIGS. 1 and 2
, attention is now drawn to the skate frame
20
. The frame
20
is preferably configured as an inverted, substantially U-shaped elongate member. The spine of the frame
20
defines a shoe mounting portion
50
and the downwardly depending sides thereof defined first and second sidewalls
52
and
53
. The first and second sidewalls
52
and
53
are held in spaced parallel disposition by the shoe mounting portion
50
, such that a plurality of longitudinally aligned wheels
24
are receivable between the lower ends of the sidewalls
52
and
53
. Although the frame
20
is illustrated as a single-piece frame having sidewalls integrally formed with the shoe mounting portion, other configurations, such as two- and three-piece frames, are also within the scope of the invention and are described in greater detail below.
The wheels
24
are conventional roller skate wheels well-known in the art. Each wheel
24
has an elastomeric tire
54
mounted on a hub
56
. Each wheel
24
is journaled on bearings and is rotatably fastened between the first and second sidewalls
52
and
53
on an axle bolt
58
. The axle bolt
58
extends between laterally aligned first and second axle mounting holes
60
and
61
(
FIG. 2
) located in the lower ends of the first and second sidewalls
52
and
53
. The axle bolt
58
also extends laterally through two rotary bearings (not shown) located in the hub
56
of each wheel
24
. Preferably, the wheels
24
are journaled to the frame
20
in a longitudinally aligned arrangement and are positioned substantially midway between the lateral and medial sides of the shoe portion
22
.
The base
32
of the shoe portion
22
may be rigidly fastened to the shoe mounting portion
50
of the frame
20
by well-known fasteners (not shown), such as bolts or rivets. The fasteners extend vertically through the toe and heel ends
34
and
36
of the base
32
and into corresponding holes extending vertically through the shoe mounting portion
50
. Although it is preferred that the shoe portion
22
be rigidly fastened to the frame
20
, other configurations, such as detachably or hingedly attaching the shoe portion to the skate frame, are also within the scope of the present invention.
The frame
20
includes an inner skin
62
, core material
64
, structural filler material
66
and an outer skin
68
. Within the meaning of this specification, skins are used to designate layer or layers of material. The inner and outer skins
62
and
68
are preferably constructed in a manner well-known in the art from a lightweight and high strength material, such as a carbon fiber reinforced thermosetting polymer or a fiber reinforced thermoplastic. Preferably, the filler material
66
is also a lightweight and high strength material having structural properties, such as strength and stiffness, greater than the core material
64
. In particular, the filler material
66
can be the same composite material used to construct the inner and outer skins
62
and
68
, or the filler material
66
can be some other material that is more structural and dense than the core material
64
. Thus, while the type of material used as filler material
66
is not important to the invention, it is important that the filler material
66
is more structural in terms of stiffness, density, and strength than the core material
64
. Furthermore, although the preferred embodiment is illustrated and described as having a separate plug of filler material
66
, other configurations, such as a frame without filler material, are also within the scope of the present invention and are described in greater detail below.
Still referring to
FIGS. 1 and 2
, core material
64
is disposed within the first and second sidewalls
52
and
53
by being sandwiched between the inner and outer skins
62
and
68
of both sidewalls
52
and
53
. The core material
64
has an average density that is less than the skins
62
and
68
and the filler material
66
. Preferably, the core material
64
is an unreinforced or reinforced polymer, such as a structural foam or a syntactic foam, or a natural material, such as wood. The core material
64
may also be a viscoelastic material. The core material
64
is substantially rectangular in configuration and is disposed within each sidewall
52
and
53
, such that the length of the core material
64
is parallel to a longitudinal axis extending between the ends of the frame
20
. The core material
64
is located a predetermined distance above the first and second axle mounting holes
60
and
61
of the first and second sidewalls
52
and
53
. A plug of filler material
66
surrounds the axle mounting holes
60
and
61
and borders the lower end of the core material
64
. As configured, the filler material
66
absorbs at least a portion of the loads associated with the axle bolt
58
(
FIG. 1
) received therein. Because filler material
66
surrounds the axle mounting holes
60
and
61
, it eliminates direct contact between the axle bolt
58
and the core material
64
, thereby minimizing the risk of damage to the core material
64
from the axle bolt
58
.
Although it is preferred to have a plug of filler material
66
surrounding the axle mounting holes
60
and
61
, other configurations are also within scope of the invention. As seen in the nonlimiting example of
FIG. 3
, the frame
20
a
may be constructed without filler material. The frame
20
a
is constructed in the same manner as described above for the preferred embodiment, with the exception that core material
64
a
is sealed within the first and second sidewalls
52
and
53
by the inner and outer skins
62
a
and
68
a
. The inner and outer skins
62
a
and
68
a
seal the core material
64
a
within the frame
20
a
, such that the skins
62
a
and
68
a
border all of the edges of the core material
64
a
. As configured, the skins
62
a
and
68
a
combine to surround the axle mounting holes
60
a
and
61
a
. Thus, although filler material is preferred, it is not necessary for the present invention.
As may be seen better by referring back to the preferred embodiment of
FIG. 1
, core material
64
extends nearly the length of the frame
20
. The longitudinal ends of the core material
64
are sealed by the inner and outer skins
62
and
68
, thereby avoiding structural failure or degradation of the core material
64
due to concentrated loads, abrasion and/or impact. Furthermore, as seen in
FIG. 2
, to limit damage to the core material
64
due to concentrated loads associated with the attachment of the shoe portion
22
to the frame
20
, there is no core material
64
disposed within the shoe mounting portion
50
. Thus, when the shoe portion
22
is attached to the shoe mounting portion
50
in the manner described above, there is no direct contact loading between the fasteners (not shown) attaching the shoe portion
22
to the frame
20
and the core material
64
.
As configured, the risk of damage to the core material
64
from the shoe portion
22
, the wheels
24
and direct exposure to the environment is minimized by utilizing an enclosed torsion box construction, wherein the core material
64
is sealed within the frame
20
. Damage to the core material
64
is also minimized by removing core material from at least the load introduction portions of the frame
20
, wherein loads associated with the wheels
24
and shoe portion
22
are transferred to the frame
20
. Furthermore, because the core material
64
has a density that is less than that of either the filler material
66
or the material used to construct the inner and outer skins
62
and
68
, and because it occupies a substantial volume within the sidewalls
52
and
53
, the frame
20
is lighter than a comparable frame without the core.
Although it is preferred to dispose core material
64
within the first and second sidewalls
52
and
53
of a U-shaped frame, other locations of the core material
64
are also within the scope of the present invention. As seen in the first alternate embodiment of
FIGS. 4 and 5
, core material
164
may be located within the shoe mounting portion
150
of the frame
120
. In this alternate embodiment, the frame
120
is constructed as described above for the preferred embodiment, except that core material
164
is now positioned between the inner and outer skins
162
and
168
of the shoe mounting portion
150
instead of being disposed within the sidewalls
152
and
153
. As may be seen better in
FIG. 5
, core material
164
extends between the sidewalls
152
and
153
, and is positioned above the wheels. Referring back to
FIG. 4
, the core material
164
contours the tops of the wheels
124
(shown in phantom), such that the core material
164
, bounded along its lower edge by the skin
162
, defines C-shaped wheel wells around the upper surface of each wheel
124
.
As configured within the shoe mounting portion
150
of the skate frame
120
, the core material
164
has a variable depth along the longitudinal direction of the skate frame
120
. As seen better in
FIG. 5
, the core material:
164
is not only positioned between the skins
162
and
168
of the shoe mounting portion
150
, but the core material
164
also extends between the first and second sidewalls
152
and
153
of the frame
120
.
Preferably, the upper shoe mounting portion
150
also includes a pair of vertically extending shoe attachment bores
151
a
and
151
b
. The shoe attachment bores
151
a
and
151
b
are each sized to receive a shoe attachment fastener (not shown) vertically therethrough. The fasteners are adapted to attach the toe and heel ends of the shoe portion
22
(
FIG. 1
) to the frame
120
. Preferably, the edges of the core material
164
adjacent the attachment bores
151
a
and
151
b
are sealed within the shoe mounting portion
150
by the skins
162
and
168
to eliminate direct contact between the core material
164
and the shoe attachment fasteners. Thus, the core material
164
is sealed within the shoe mounting portion
150
by the skins
162
and
168
.
As seen in the second alternate embodiment of
FIG. 6
, core material
264
may be located within multiple locations of the frame
220
. In this alternate embodiment, the frame
220
is constructed as described above for the preferred embodiment and first alternate embodiment, except that core material
264
is now disposed between the skins
262
and
268
of both the shoe mounting portion
250
and the first and second sidewalls
252
and
253
. The axle mounting holes
260
and
261
of this embodiment are surrounded by a plug of filler material
266
to eliminate direct contact between the core material
264
and the wheel axles (not shown). Thus, in this second alternate embodiment of the invention, core material
264
is located within both the shoe mounting portion
250
and the sidewalls
252
and
253
, and is sealed therein by the skins
262
and
268
and/or the filler material
266
.
Although a single piece frame having first and second sidewalls integrally formed with the shoe mounting portion is the preferred embodiment of the present invention, other configurations are also within the scope of the present invention. As seen in a first nonlimiting example of
FIG. 7
, the frame
320
may be a three-piece frame. The frame
320
is constructed the same as the preferred embodiment, except that the shoe mounting portion
350
and the first and second sidewalls
352
and
353
are all separate components of the frame
320
. The sidewalls
352
and
353
, having core material
364
sealed therein by the skins
362
and
368
, are fastened to the shoe mounting portion
350
by screws, adhesive or in another manner well-known in the art. Preferably, the shoe mounting portion
350
is constructed from an aluminum or plastic material.
As a second nonlimiting example, the frame
420
may be a two-piece frame. Referring to
FIG. 8
, each piece
490
and
492
of the frame
420
is configured as an inverted āLā and is preferably constructed from the same material as described above for the other example. The downwardly depending spine of each piece
490
and
492
defines the sidewalls
452
and
453
. Core material
464
is sealed within each sidewall
452
and
453
in a manner described above for the preferred embodiment. Preferably, the core has a thickness contour, such that the external surface of the skate frame has a contour which reflects the contour of the core. Alternatively, and as seen in
FIG. 9
, each sidewall
452
and
453
has an inner and outer half
465
and
466
. Each half may be stamped from a rigid material, such as aluminum, to define a contoured section. The contoured section is sized to receive the core material
464
therein, such that when the two halves
465
and
466
are joined together in a manner well-known in the art, the core material
464
is disposed within the contoured sections of the inner and outer halves
465
and
466
of each sidewall
452
and
453
. The base portions of each piece
490
and
492
project orthogonally from the sidewalls
452
and
453
and are adapted to be fastened together in a manner well-known in the art. As fastened, the base portions combine to define the shoe mounting portion
450
.
In a preferred method of constructing a frame
20
, core material
64
may be sealed within the sidewalls
52
and
53
of the frame
20
. First, uncured inner skin composite material reinforced with fibers is laid up on a male mold until the desired thickness is achieved. The mold is substantially U-shaped in configuration. Then, core material
64
is disposed within the mold in the desired location. In the preferred embodiment, core material is disposed along the sides of the sidewalls of the inner skin. Although it is preferred that core material is positioned along the arms of the inner skin, core material may be disposed along other portions of the inner skin, such as along the arcuate portion or along both the arcuate portion and the arms of the inner skin.
Filler material
66
is then placed in the desired location within the mold. Uncured outer skin composite material is then applied to the mold, such that the core material and filler material are sandwiched between the inner and outer skins. A female mold is placed over the layup and the entire layup is permitted to cure. Although a plug of filler material is preferred, other configurations, such as eliminating the plug of filler material and laying the inner and outer skins to seal the core material therein, are also within the scope of the method of the present invention.
An alternate method of constructing a frame
20
in accordance with the present invention is identical to the preferred method, as described above, with the following exceptions. In place of the outer skin composite material, a decorative sheet
500
may be applied to the mold, such that the core material and the filler material are sandwiched between the inner skin and the decorative sheet
500
. In still yet another alternate method of constructing a frame in accordance with the present invention includes the steps as outlined above for the preferred method with the following exception. As seen in
FIG. 9
, after the outer skin composite material is applied to the mold, the decorative sheet
500
is applied to the outer skin, such that the core material and filler material are sandwiched between the inner and outer skins, with a decorative sheet
500
disposed on the outer skin.
The previously described versions of the present invention have several advantages over skate frames currently available in the art. The skate frame of the present invention is lighter than solid composite or aluminum frames because a lightweight core material occupies a substantial volume within the frame. Also, because the core material is lightweight and has moderate structural properties in terms of strength and stiffness, the strength-to-weight ratio of the frame is increased. Further, because the skate frame of the present invention utilizes a core material that is less expensive than the reinforced composite material it replaces, it is more cost efficient than skate frames having an all composite construction. Finally, because core material is removed from the load introduction points associated with the wheels and shoe portion, the skate frame has a longer useful life than skate frames having a core that is in direct contact with the load introduction points. Thus, a skate frame constructed in accordance with the present invention has an increased strength-to-weight ratio and is less expensive than those currently available in the art.
From the foregoing description, it may be seen that the skate of the present invention incorporates many novel features and offers significant advantages over the prior art. It will be apparent to those of ordinary skill that the embodiments of the invention illustrated and described herein are exemplary only and, therefore, changes may be made to the foregoing embodiments. As a nonlimiting example, core material located within the sidewalls or upper surface of the skate frame may bulge outwardly, such that the sidewalls have a bubble contour to accommodate the core. Thus, it may be appreciated that various changes can be made to the preferred embodiment of the invention without departing from the spirit and scope of the invention.
Claims
- 1. A skate frame for an in-line skate, the skate having a shoe portion and a plurality of wheels capable of traversing a surface, the skate frame comprising:(a) an elongate structural member comprised of a structural material having a first average density, the structural member having first and second sidewalls each having an upper end, a lower end, an inner surface, and an outer surface, the structural member also having a shoe mounting portion spanning between at least a portion of the upper ends of the sidewalls, the first and second sidewalls having a wheel load introduction portion, wherein loads associated with the wheels are transferred to the structural member, the shoe mounting portion having a shoe load introduction portion, wherein loads associated with the shoe portion are transferred to the structural member; and (b) core material disposed within at least one of the first and second sidewalls, the core material being contained within the inner and outer side wall surfaces, the core material being absent from at least the wheel and shoe load introduction portions, wherein the core material has a second average density that is less tan the density of the structural material.
- 2. The skate frame of claim 1, wherein the core material occupies a volume within the structural member to provide the skate frame with an increased structural strength-to-weight ratio.
- 3. The skate frame of claim 2, wherein the core material comprises a structural material selected from a group consisting of viscoelastic material, unreinforced polymers, reinforced polymers, and naturally occurring fibrous and cellular materials.
- 4. The skate frame of claim 3, wherein the core material is one of structural foam, syntactic foam, or wood.
- 5. The skate frame of claim 3, wherein the core material is disposed within both the first and second sidewalls and within the shoe mounting portion.
- 6. The skate frame of claim 3, wherein the sidewalls define axle attachment bores extending laterally through the lower ends of the sidewalls, the core material extends within each sidewall from a predetermined point above the axle attachment bore to a predetermined point below the shoe mounting portion to isolate the core material from concentrated loads associated with the axle attachment bores and the shoe mounting portion.
- 7. The skate frame of claim 6, further comprising a filler material disposed within the skate frame, wherein the filler material has a density, strength, and stiffness that is greater than the core material, the filler material being disposed between the core material and wheel load introduction portions to absorb at least a portion of the loads associated with the wheels.
- 8. The skate frame of claim 7, wherein the filler material is a reinforced composite material.
- 9. The skate frame of claim 3, wherein the core material is disposed within the shoe mounting portion.
- 10. The skate frame of claim 9, wherein the core material defines a varying height along a longitudinal axis extending between the ends of the frame.
- 11. The skate frame of claim 3, wherein the shoe mounting portion and the first and second sidewalls of the structural member are separate members to define a three piece skate frame.
- 12. The skate frame of claim 11, wherein the core material is disposed within the first and second sidewalls.
- 13. The skate frame of claim 3, wherein at least a portion of the shoe mounting portion is integrally formed with the upper ends of the first and second sidewalls to define a two piece skate frame.
- 14. The skate frame of claim 13, wherein the core material is disposed within the first and second sidewalls.
- 15. The skate frame of claim 1, wherein the core is contoured, such that the skate frame is contoured on its outer surface reflecting the contour of the core material.
- 16. The skate frame of claim 15, wherein the first and second sidewalls are a composite material and the core material forms the contour section during manufacture of the skate frame.
- 17. The skate frame of claim 1, wherein each sidewall has an inner and outer half, the inner and outer halves of each sidewall being stamped or formed from a material to define a contoured section, the contoured section being sized to receive the core material therein such that when the two halves are joined together, the core material is disposed within the contoured sections of the inner and outer halves of each sidewall.
- 18. A skate frame for an in-line skate, the skate having a shoe portion and a plurality of wheels capable of traversing a surface, the skate frame comprising:(a) first and second sidewalls comprised of a structural material having a predetermined average density, each sidewall having an inner surface, an outer surface, an upper end and a lower end, the lower ends each having a wheel load introduction portion, wherein loads associated with the wheels are transferred to the sidewalls; (b) a shoe mounting portion comprised of a structural material having a predetermined average density, the shoe mounting portion being disposed between the upper ends of the first and second sidewalls, the shoe mounting portion having a shoe load introduction portion, wherein loads associated with the shoe portion are transferred to the shoe mounting portion; and (c) core material disposed within the inner and outer surfaces of at least one of the first and second sidewalls, the core material being absent from at least the wheel and shoe load introduction portions, wherein the core material has an average density less than the density of the structural material.
- 19. The skate frame of claim 10, wherein the core material is an unreinforced or reinforced material.
- 20. The skate frame of claim 19, further comprising a plug of filler material having an average density, strength, and stiffness that is greater than the core material, the filler material being disposed between the core material and wheel load introduction portions to absorb at least a portion of the loads associated with the wheels.
- 21. The skate frame of claim 18, wherein the core material is disposed within the first and second sidewalls.
- 22. The skate frame of claim 18, wherein the core material is disposed within the shoe mounting portion.
- 23. The skate frame of claim 22, wherein the core material has a varying depth along a longitudinal axis extending between the ends of the frame.
- 24. The skate frame of claim 20, wherein the core material is disposed within the first and second sidewalls and the shoe mounting portion.
- 25. A skate frame for an in-line skate, the skate having a shoe portion and a plurality of wheels capable of traversing a surface, the skate frame comprising:(a) an elongate structural member comprised of a structural material having a first average density, the structural member having first and second sidewalls each having an upper end, a lower end and an outer surface, the structural member also having a shoe mounting portion spanning between at least a portion of the upper ends of the sidewalls, the first and second sidewalls having a wheel load introduction portion, wherein loads associated with the wheels are transferred to the structural member, the shoe mounting portion having a shoe load introduction portion, wherein loads associated with the shoe portion are transferred to the structural member; and (b) core material disposed within at least one of the first and second sidewalls or within the shoe mounting portion, the core material being sealed within the sidewalls and/or the shoe mounting portion by the structural material or a filler material, the core material being absent from at least the wheel and shoe load introduction portions, wherein the core material has a second average density that is less than the density of the structural material, the core material occupies a volume within the structural member to provide the skate frame with an increased structural strength-to-weight ratio, wherein the core material comprises a rigid structural material selected from a group that comprises viscoelastic material, unreinforced polymers, reinforced polymers, and naturally occurring fibrous or cellular materials, wherein the sidewalls define axle attachment bores extending laterally through the lower ends of the sidewalls, the core material extends within each sidewall from a predetermined point above the axle attachment bore to a predetermined point below the shoe mounting portion to isolate the core material from concentrated loads associated with the axle attachment bores and the shoe mounting portion, wherein the filler material has a density, strength, and stiffness that is greater than the core material, the filler material being disposed between the core material and wheel load introduction portions to absorb at least a portion of the loads associated with the wheels.
- 26. The skate frame of claim 25, wherein the filler material is a reinforced composite material.
- 27. A skate frame for an in-line skate, the skate having a shoe portion and a plurality of wheels capable of traversing a surface, the skate frame comprising:(a) an elongate structural member comprised of a structural material having a first average density, the structural member having first and second sidewalls each having an upper end, a lower end and an outer surface, the structural member also having a shoe mounting portion spanning between at least a portion of the upper ends of the sidewalls, the first and second sidewalls having a wheel load introduction portion, wherein loads associated with the wheels are transferred to the structural member, the shoe mounting portion having a shoe load introduction portion, wherein s associated with the shoe portion are transferred to the structural member; and (b) core material disposed within at least one of the first and second sidewalls or within the shoe mounting portion, the core material being sealed within the sidewalls and/or the shoe mounting portion by the structural material or a filler material, the core material being absent from at least the wheel and shoe load introduction portions, wherein the core material has a second average density that is less than the density of the structural material, the core material occupies a volume within the structural member to provide the skate frame with an increased structural strength-to-weight ratio, wherein the core material comprises a rigid structural material selected from a group that comprises viscoelastic material, unreinforced polymers, reinforced polymers, and naturally occurring fibrous or cellular materials, wherein at least a portion of the shoe mounting portion is integrally formed with the upper ends of the first and second sidewalls to define a two piece skate frame.
- 28. The skate frame of claim 27, wherein the core material is disposed within the first and second sidewalls.
- 29. A skate frame for an in-line skate, the skate having a shoe portion and a plurality of wheels capable of traversing a surface, the skate frame comprising:(a) an elongate structural member comprised of a structural material having a first average density, the structural member having first and second sidewalls each having an upper end, a lower end and an outer surface, the structural member also having a shoe mounting portion spanning between at least a portion of the upper ends of the sidewalls, the first and second sidewalls having a wheel load introduction portion, wherein loads associated with the wheels are transferred to the structural member, the shoe mounting portion having a shoe load introduction portion, wherein loads associated with the shoe portion are transferred to the structural member; and (b) core material disposed within at least one of the first and second sidewalls or within the shoe mounting portion, the core material being sealed within the sidewalls and/or the shoe mounting portion by the structural material or a filler material, the core material being absent from at least the wheel and shoe load introduction portions, wherein each sidewall has an inner and outer half, the inner and outer halves of each sidewall being stamped or formed from a material to define a contoured section, the contoured section being sized to receive the core material therein such that when the two halves are joined together, the core material is disposed within the contoured sections of the inner and outer halves of each sidewall.
- 30. A skate frame for an in-line skate, the skate having a shoe portion and a plurality of wheels capable of traversing a surface, the skate frame comprising:(a) first and second sidewalls comprised of a structural material having a predetermined average density, each sidewall having an upper end and a lower end, the lower ends each having a wheel load introduction portion, wherein loads associated with the wheels are transferred to the sidewalls; (b) a shoe mounting portion comprised of a structural material having a predetermined average density, the shoe mounting portion being disposed between the upper ends of the first and second sidewalls, the shoe mounting portion having a shoe load introduction portion, wherein loads associated with the shoe portion are transferred to the shoe mounting portion; (c) core material disposed within at least one of the first and second sidewalls or within the shoe mounting portion, the core material being absent from at least the wheel and shoe load introduction portions, wherein the core material is an unreinforced or reinforced material having an average density that is less than the density of the material for both sidewalls and shoe mounting portion; and (d) a plug of filler material having an average density, strength, and stiffness that is greater than the core material, the filler material being disposed between the core material and wheel load introduction portions to absorb at least a portion of the loads associated with the wheels.
US Referenced Citations (28)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0 321 026 |
Jun 1989 |
EP |
WO 9802217 |
Jan 1998 |
WO |