U.S. patent application number 09/199398 was filed with the patent office on 2001-11-08 for foam core in-line skate frame.
Invention is credited to GRANDE, DODD H..
Application Number | 20010038181 09/199398 |
Document ID | / |
Family ID | 22737335 |
Filed Date | 2001-11-08 |
United States Patent
Application |
20010038181 |
Kind Code |
A1 |
GRANDE, DODD H. |
November 8, 2001 |
FOAM CORE IN-LINE SKATE FRAME
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.
Inventors: |
GRANDE, DODD H.; (SEATTLE,
WA) |
Correspondence
Address: |
CHRISTENSEN, O'CONNOR, JOHNSON, KINDNESS, PLLC
1420 FIFTH AVENUE
SUITE 2800
SEATTLE
WA
98101-2347
US
|
Family ID: |
22737335 |
Appl. No.: |
09/199398 |
Filed: |
November 24, 1998 |
Current U.S.
Class: |
280/11.221 |
Current CPC
Class: |
A63C 2203/42 20130101;
A63C 17/068 20130101 |
Class at
Publication: |
280/11.221 |
International
Class: |
A63C 017/02 |
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
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 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.
2. The skate frame of claim 1, 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.
3. The skate frame of claim 2, 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.
4. The skate frame of claims 3, wherein the core material is a
structural foam, syntactic foam, or wood.
5. The skate frame of claim 3, wherein the core material is
disposed within the first and second sidewalls.
6. 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.
7. 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.
8. The skate frame of claim 7, 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.
9. The skate frame of claim 8, wherein the filler material is a
reinforced composite material.
10. The skate frame of claim 3, wherein the core material is
disposed within the shoe mounting portion.
11. The skate frame of claim 10, wherein the core material defines
a varying height along a longitudinal axis extending between the
ends of the frame.
12. 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.
13. The skate frame of claim 12, wherein the core material is
disposed within the first and second sidewalls.
14. 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.
15. The skate frame of claim 14, wherein the core material is
disposed within the first and second sidewalls.
16. The skate frame of claim 1, wherein the core material is
disposed within the first and second sidewalls and the core is
contoured, such that the skate frame is contoured on its outer
surface reflecting the contour of the core material.
17. The skate frame of claim 16, wherein the first and second
sidewalls are a composite material and the core material forms the
contour section during manufacture of the skate frame.
18. 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.
19. 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; and (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.
20. The skate frame of claim 19, 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.
21. The skate frame of claim 20, 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.
22. The skate frame of claim 19, wherein the core material is
disposed within the first and second sidewalls.
23. The skate frame of claim 19, wherein the core material is
disposed within the shoe mounting portion.
24. The skate frame of claim 23, wherein the core material has a
varying depth along a longitudinal axis extending between the ends
of the frame.
25. The skate frame of claim 21, wherein the core material is
disposed within the first and second sidewalls and the shoe
mounting portion.
26. 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 a forward end, a rear end, an inner
surface, an outer surface, first and second sidewalls each having
an upper end and a lower end, and a shoe mounting portion spanning
between the upper ends of the sidewalls, the lower ends of the
first and second sidewalls being spaced to receive the wheels
therebetween such that there is a gap extending along a
longitudinal axis defined between the forward and rear ends of the
structural member, the gap being defined between the inner and
outer surfaces of the shoe mounting portion; and (b) core material
disposed within the gap and extending between the first and second
sidewalls.
27. The skate frame of claim 26, wherein the core material is an
unreinforced material having a second average density that is less
than the density of the structural material member.
28. The skate frame of claim 27, wherein the core material
comprises a rigid structural material selected from a group that
comprises reinforced polymers, unreinforced polymers, viscoelastic
material, and naturally fibrous or cellular materials.
29. The skate frame of claim 28, wherein the core material has a
varying height along a longitudinal axis extending between the
forward and rear ends of the frame.
30. A method of constructing a skate frame for an in-line skate
having a shoe portion and a plurality of longitudinally aligned
wheels capable of traversing a surface, the method comprising: (a)
forming a first skin on a mold; (b) positioning core material at a
predetermined location on the first skin; (c) forming a second skin
over the first skin such that the core material is positioned and
sealed between the first and second skins; and (d) curing the
frame.
31. The method of claim 30, wherein the core material is an
unreinforced material having an average density that is less than
the density of the first and second skins by a predetermined
amount.
32. The method of claim 31, further comprises disposing a plug of
filler material between the first and second skins before curing to
absorb at least a portion of loads associated with the wheels.
33. A method of constructing a skate frame for an in-line skate
having a shoe portion and a plurality of longitudinally aligned
wheels capable of traversing a surface, the method comprising: (a)
forming a first skin on a mold; (b) positioning core material at a
predetermined location on the first skin; (c) layering a decorative
sheet over the core material to seal the core material between the
first skin and the decorative sheet; and (d) curing the frame.
34. The method of claim 33, further comprising the step of forming
a second skin over the core material before layering the decorative
sheet, such that the second skin is positioned between the core
material and the decorative sheet.
Description
FIELD OF THE INVENTION
[0001] 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
[0002] 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.
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] In an alternate embodiment of the present invention, core
material is disposed within the shoe mounting portion.
[0015] 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.
[0016] 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.
[0017] 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
[0018] 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:
[0019] 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;
[0020] 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;
[0021] 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;
[0022] 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;
[0023] 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 5-5 of FIG. 4 showing
core material disposed within the shoe mounting portion of the
skate frame;
[0024] 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;
[0025] 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;
[0026] 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
[0027] 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
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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 20a may be constructed
without filler material. The frame 20a is constructed in the same
manner as described above for the preferred embodiment, with the
exception that core material 64a is sealed within the first and
second sidewalls 52 and 53 by the inner and outer skins 62a and
68a. The inner and outer skins 62a and 68a seal the core material
64a within the frame 20a, such that the skins 62a and 68a border
all of the edges of the core material 64a. As configured, the skins
62a and 68a combine to surround the axle mounting holes 60a and
61a. Thus, although filler material is preferred, it is not
necessary for the present invention.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] Preferably, the upper shoe mounting portion 150 also
includes a pair of vertically extending shoe attachment bores 151a
and 151b. The shoe attachment bores 151a and 151b 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
151a and 151b 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.
[0042] 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.
[0043] 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.
[0044] 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 "L" 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.
[0045] 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.
[0046] 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.
[0047] 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.
[0048] 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.
[0049] 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.
* * * * *