U.S. patent application number 09/902236 was filed with the patent office on 2001-12-13 for spring cushioned shoe.
Invention is credited to Krafsur, David S., LeVert, Francis E..
Application Number | 20010049888 09/902236 |
Document ID | / |
Family ID | 26829697 |
Filed Date | 2001-12-13 |
United States Patent
Application |
20010049888 |
Kind Code |
A1 |
Krafsur, David S. ; et
al. |
December 13, 2001 |
Spring cushioned shoe
Abstract
A spring cushioned shoe is disclosed. The shoe includes a sole
assembly that has a first spring disposed within a vacuity in the
heel portion of the assembly, and a second spring disposed within a
vacuity in the ball portion of the assembly. The springs are, e.g.,
wave springs that extend vertically from the upper to the lower
internal boundaries of the vacuities.
Inventors: |
Krafsur, David S.; (Lenoir
City, TN) ; LeVert, Francis E.; (Knoxville,
TN) |
Correspondence
Address: |
DAVID A. SIMONS
Fish & Richardson P.C.
225 Franklin Street
BOSTON
MA
02110-2804
US
|
Family ID: |
26829697 |
Appl. No.: |
09/902236 |
Filed: |
July 10, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09902236 |
Jul 10, 2001 |
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09419330 |
Oct 15, 1999 |
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6282814 |
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60131658 |
Apr 29, 1999 |
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Current U.S.
Class: |
36/27 ; 36/28;
36/38 |
Current CPC
Class: |
A43B 13/183 20130101;
A43B 7/144 20130101; A43B 7/1425 20130101 |
Class at
Publication: |
36/27 ; 36/28;
36/38 |
International
Class: |
A43B 013/28; A43B
013/18 |
Claims
1. A sole assembly for an article of footwear, the sole assembly
having a heel region and a ball region, and the sole assembly
comprising: a first wave spring disposed within the heel region;
and a second wave spring disposed within the ball region.
2. The sole assembly of claim 1, wherein the wave springs are
crest-to-crest wave springs.
3. The sole assembly of claim 1, wherein the wave springs are
selected from the group consisting of interlaced wave springs and
nested wave springs.
4. The sole assembly of claim 1, further comprising a first vacuity
in the heel region and a second vacuity in the ball region, wherein
the first wave spring is disposed within the first vacuity, and the
second wave spring is disposed within the second vacuity.
5. The sole assembly of claim 4, further comprising a receiving
clip disposed within the first vacuity, the receiving clip having a
rigid upper internal surface and a rigid lower internal surface,
the upper and lower internal surfaces each including a protrusion
that defines a groove, wherein the first wave spring has an upper
and a lower terminal shim ends, and the first wave spring is
disposed within the receiving clip such that its upper terminal
shim end is disposed within the groove of the upper internal
surface, and its lower terminal shim end is disposed within the
groove of the lower internal surface.
6. The sole assembly of claim 5, wherein the receiving clip further
comprises a pair of opposed spring compression limiters attached to
the upper and lower internal surfaces respectively, the spring
compression limiters engaging upper and lower sides of the wave
spring respectively.
7. The sole assembly of claim 6, wherein the spring compression
limiters are generally cylindrically shaped.
8. The sole assembly of claim 5, wherein the clip is U-shaped.
9. The sole assembly of claim 4, further comprising upper and a
lower plastic plates disposed within the first vacuity, on opposite
sides of the vacuity, each plate comprising a protrusion that
defines a groove, wherein the first wave spring has an upper and a
lower terminal shim end, and the first wave spring is disposed
between the plates such that its upper terminal shim end is
disposed within the groove of the upper plate, and its lower
terminal shim end is disposed within the groove of the lower
plate.
10. The sole assembly of claim 9, further comprising a pair of
opposed spring compression limiters attached to the upper and lower
plates respectively, the spring compression limiters engaging upper
and lower sides of the wave spring respectively.
11. The sole assembly of claim 1, wherein the first wave spring has
a greater free height than the second wave spring.
12. A spring cushioned shoe comprising: an upper support member for
receiving a human foot; and a sole assembly affixed to the upper
support member, the sole assembly comprising a first wave spring
disposed within a heel region of the assembly, and a second wave
spring disposed within a ball region of the assembly.
13. The sole assembly of claim 4, wherein the first vacuity is
bounded vertically by opposed first upper and first lower internal
surfaces, the second vacuity is bounded vertically by opposed
second upper and second lower internal surfaces, and wherein the
first wave spring extends vertically from the first upper surface
to the first lower surface, and the second wave spring extends
vertically from the second upper surface to the second lower
surface.
14. The sole assembly of claim 4, further comprising a lower sole,
a middle sole, and an upper sole, the middle sole including the
first and second vacuities.
15. The sole assembly of claim 4, wherein a distance between the
first upper and first lower surfaces of the first vacuity is
greater than a distance between the second upper and second lower
surfaces of the second vacuity.
16. The sole assembly of claim 15, wherein the first wave spring
has a free height greater than a free height of the second wave
spring.
17. The sole assembly of claim 4, further comprising upper and
lower plates disposed within the first vacuity, on opposite sides
of the vacuity, wherein the first wave spring is disposed between
the upper and lower plates.
18. The sole assembly of claim 17, wherein the upper and lower
plates each comprise a projection extending from a plane of the
plate, and wherein the first wave spring has an upper and a lower
end, and the first wave spring is disposed between the plates such
that its upper end fits around the projection of the upper plate,
and its lower end fits around the projection of the lower
plate.
19. The sole assembly of claim 18, wherein the projections
extending from the upper and lower plates are generally circular in
shape.
20. The sole assembly of claim 18, wherein the upper and lower ends
of the first wave spring are terminal shim ends.
21. The sole assembly of claim 1, wherein the first and second wave
springs are configured such that routine compressive forces applied
by a user wearing the article of footwear do not fully compress the
first and second wave springs.
22. The sole assembly of claim 1, wherein the heel region includes
a plurality of wave springs disposed therein.
23. The sole assembly of claim 22, wherein the ball region includes
a plurality of wave springs disposed therein.
24. The sole assembly of claim 1, wherein the ball region includes
a plurality of wave springs disposed therein.
Description
CROSS-REFERENCE OF RELATED APPLICATIONS
[0001] Pursuant to 35 U.S.C. Section 119, the benefit of priority
from Provisional Application Serial No. 60/131,658 with a filing
date of Apr. 29, 1999 is claimed for this Non-Provisional
Application.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] This invention relates to the use of wave springs to cushion
a shoe. Wave springs allow for reduced impact on the user during
foot strike, thus increasing comfort and decreasing injury. Also,
the wave springs will return a portion of the impact energy to the
user for more efficient jumping, walking and/or running.
[0004] 2. Background Art
[0005] People involved in normal exercise programs are always
seeking new equipment that can minimize the risk of injury to parts
of the body caused by stress due to a foot strike. Athletes are
also continually looking for ways to improve their performance
levels in a variety of athletic and aerobic events that involve
walking, running, or jumping while at the same time, taking steps
to reduce the wear and tear attendant to the pounding endured by
joints and bones. This can be achieved to some degree by the use of
improved sporting equipment and more specifically improved shoes
for both athletes and non-athletes.
[0006] When participating in sports, especially high impact sports
such as volleyball and basketball, the foot of the participant;
specifically the ball and heel areas are prone to extreme
mechanical stress due to the force that will be imparted when the
foot strikes a relative incompressible surface. This force, which
will vary depending on the type of event that a person is involved
in and the mass of the person, can be as large as five times the
body weight of the participant. The reaction force resulting from
contact with a non-yielding surface causes great shock to the body
that can injure the lower back and all rotating joints of the
leg.
[0007] Unlike events that involve jumping, the mechanics of running
or walking involve a prescribed set of motions insofar as the foot
is concerned. Except in those events that involve sprinting, the
heel impacts the ground first, the weight then shifts forward onto
the ball of the foot in a rolling manner with the toe region
providing the last contact with the ground. The initial impact in
the heel area is of special interest with non-sprinting runners
because; it is here that landing forces come into play. It is
desirable to absorb as much impact energy as possible, consistent
with providing a stable landing and without slowing down the
runner. It is also desirable to avoid the complete loss of energy
absorbed by the shoe at impact. Also, since the ball and toe areas
of the foot are the last to leave the surface in contact with the
ground, it is desirable to recover some of the landing energy
absorbed in the initial impact. A number of patents relate to shoe
constructions, which are variously designed to address one or more
of the desirable shoe features discussed above, are reviewed
below:
[0008] U.S. Pat. No. 5,896,679 discloses an article of footwear
with a spring mechanism located in the heel area of a shoe
including two plates connected one to the other and attachment to
the lower surface of the shoe sole. The invention of the '679
patent provides a heel mechanism that absorbs the shock or impact
foot strikes. U.S. Pat. No. 5,743,028 (T. D. Lombardino) discloses
a plurality of vertically compression springs located in the heel
area of a running shoe. The springs of the '028 patent are housed
in a hermetically sealed unit filled with a pressurized gas which
in combination with the springs provides a shock absorbing and
energy return system. The springs having substantially a coiled
appearance where each spiral coil must provide a torsional spring
force and collapse in a vertical stack commonly called the solid
height when totally compressed. Because of their design, these
springs must have significant free heights to accord one with large
deflections. U.S. Pat. No. 4,815,221, Diaz discloses an energy
control system comprising a spring plate having a plurality of
spring projections distributed over the surface of the plate which
is placed in a vacuity formed within the mid-sole of an athletic
shoe. U.S. Pat. No. 5,511,324 (R. Smith) discloses a shoe in which
a coil spring extends from the top through the wedge sole in the
heel area of an athletic shoe. U.S. Pat. No. 5,437,110 (Goldston et
al.) discloses an adjustable shoe heel spring and stabilizer device
for a running shoe including a spring mechanism disposed in the
mid-sole of the shoe. The shoe heel spring includes a cantilevered
spring member and an adjustable fulcrum. A shoe designed
specifically for jumping is disclosed in U.S. Pat. No. 5,916,071
(Y. Y. Lee). Lee discloses a shoe mounted on a frame containing a
coil spring that extends horizontally from the regions of the frame
located at the toe and heel areas of the shoe which expands and
contracts during walking and jumping. U.S. Pat. No. 4,492,046
(Kosova) discloses a running shoe which includes a spring wire
located in a longitudinal slot in the shoe sole extending from the
back edge thereof into the arch region. U.S. Pat. No. 2,447,603
(Snyder) discloses a U-shaped spring plate disposed between the
heel of the shoe and overlying a rear portion of the shoe sole.
Several other U.S. patents of related art are: U.S. Pat. No.
5,875,567 (R. Bayley); U.S. Pat. No.5,269,081 (Gray); U.S. Pat.
No.2,444,865 (Warrington); U.S. Pat. No.3,822,490 (Murawski); U.S.
Pat. No.4,592,153 (Jacinta); and, U.S. Pat. No. 5,343,636 (Sabol);
U.S. Pat. No.5,435,079 (Gallegos); U.S. Pat. No.5,502,901 (Brown);
U.S. Pat. No.5,517,769 (Zhao); and U.S. Pat. No.5,544,431
(Dixon).
[0009] Revisiting and expanding the above mentioned desirable
attributes of a shoe of this type, there is a need for a shoe that
enhances the performance of the wearer by providing a substantial
spring force working through a significant distance while requiring
a minimum volume for deployment. In addition there is a need for a
shoe designed with a multiplicity of springs that also assists in
propelling the foot off the ground while still maintaining
sufficient lateral stability of the shoe for quick side-to-side
movement of the wearer. This performance enhancement can be
achieved by temporarily storing the shock energy imparted by foot
strike and returning a substantial amount of the energy to the
wearer's foot during the propelling-off portion of the stride.
Also, there is a need to assure adequate spring fatigue life by
limiting maximum stresses and preventing compression to the
spring's solid height.
[0010] The prior art cited above has disclosed spring devices in
athletic shoes for the purposes of absorbing shock and returning
energy to the wearer's foot.
[0011] As can be seen from the background art, there have been many
attempts to add spring cushioning to shoes. However, one only need
to look at the current market to see that spring cushioned shoes
are not commonly available.
[0012] Accordingly, it is an object of this invention to provide a
spring-cushioned shoe that provides large heel deceleration and
ball acceleration during the foot strike.
[0013] A second object of this invention is to provide a shoe with
a multiplicity of springs located at the heel and ball regions of
the foot.
[0014] A third object of this invention is to provide a shoe that
returns, by way of the spring force, a substantial energy stored in
the springs during the initial compression cycle of the heel or
ball area of the foot.
[0015] A further object is to provide a shoe with maximum force and
deflection within a minimal volume, as well as lateral stability.
Other objects of this invention will become obvious during the
review of the figures and the detailed description of the shoes of
this invention.
BRIEF SUMMARY OF THE INVENTION
[0016] The present invention provides cushioning for a shoe that
utilizes wave springs that are placed in the ball and heel areas of
the sole of a shoe. It should be obvious to one skilled in the art
that the placement of the wave springs is not limited to only the
ball and heel areas of the shoe. In the present invention, the
middle portion sole of the shoe sole assembly is made of foam with
vacuities located at or near the ball and heel regions of the foot
in order to accommodate placement of the springs. There are also
numerous other methods and designs to place the wave springs into a
shoe for cushioning and energy return. The ensuing description of
the present invention discloses only a limited number of the
countless methods and variations thereof that may be used. The
advantages of the present invention will become apparent from
reading the description of the invention in the preferred
embodiments given below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 illustrates a side view of the preferred embodiment
of the spring-cushioned shoe.
[0018] FIG. 2 illustrates a cross sectional view of the
spring-cushioned shoe taken in the heel region of the spring
cushioned shoe.
[0019] FIG. 3 illustrates a view of the wave spring component of
the preferred embodiment
[0020] FIG. 4 illustrates a plan view of the outer sole of the
spring-cushioned shoe.
[0021] FIG. 5 illustrates a side view of the second embodiment of
the spring cushioned shoe.
[0022] FIG. 6 illustrates a plan view of the outer sole of the
second embodiment of the spring-cushioned shoe.
[0023] FIG. 7 illustrates a sectional view of one of the spring
assemblies of the second embodiment of the spring-cushioned shoe
with stabilizer and compression limiter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] This invention relates to the use of ordinary compression
springs as an integral part of shoes to cushion the impact of foot
strikes and to provide recuperative energy return to the wearer. A
spring-cushioned shoe incorporating the various features of the
present invention is illustrated generally at 2 in FIGS. 1 and 2.
The spring-cushioned shoe 2 shall hereafter be referred to as SCS
2.
[0025] The SCS 2 in FIG. 1 comprises: an upper shoe portion 5
firmly attached to shoe sole assembly 4. The shoe sole assembly 4
includes an outer sole 4A with first and second surfaces; middle
sole 4B having first and second surfaces positioned such that its
first surface is adhesively attached to the second surface of outer
sole 4A; and, inner sole 4C whose first surface is adhesively
attached to the second surface of middle sole 4B and whose second
surface is in working contact with the lower region of upper shoe
portion 5. In the present invention, the middle sole 4B is composed
of foamed polymeric material, and the inner and outer soles 4A and
4C are made of solid polymeric materials. Particularly, the outer
sole 4A is composed of ethyl vinyl acetate with the first surface
of outer sole 4A having tractive characteristics. As shown in FIG.
1, the middle sole 4B is designed to include vacuities 6 and 7.
Vacuity 6, the extent of which is defined by vertically opposing
surfaces 8A and 8B of foamed polymeric material of middle sole
assembly 4B, was formed in the heel region 8C of SCS 2. The
surfaces 8A and 8B which are set apart from the second and first
surfaces of middle sole 4B, respectively, define thick sections of
middle sole 4B at the heel area of the shoe sole assembly 4 into
which cylindrical countersunk volumes 11A and 11B, respectively are
formed as shown in Fig.2. Vacuity 7 is disposed between vertically
opposing surfaces 10A and 10B of foamed polymeric material 4B in
the region 10C of shoe sole assembly 4. Like surfaces 8A and 8B,
surfaces 10A and 10B define thick sections of the polymeric
material of middle sole 4B located below and above the vacuity 7 in
the vertical direction such that cylindrical countersunk volumes
16a and 16b (not shown in either FIG. 1 or 2) can be formed
therein. The cylindrical countersunk volumes 11A and 11B and 16A
and 16B provide vertical stabilization and retention of the wave
springs 15 and 19. The shoe sole assembly 4 is firmly attached to
upper portion 5 of SCS 2. Wave springs 15 and 19 are deployed in
vacuities 6 and 7 of foamed polymeric material 4B of shoe sole
assembly 4, respectively.
[0026] The wave springs 15 and 19 are substantially identical to
wave springs described by Greenhill in U.S. Pat. No. 4,901,987.
Greenhill describes a multi turn compression spring with distinct
crests and troughs. A separate drawing of the wave spring 15 is
presented in FIG. 3 for illustrative purposes. Wave spring 15 with
circular flat shim ends 15A and 15B and wave crest 15C and wave
trough 15D with prescribed periodicity are shown in FIG. 3. FIG. 3
illustrates the configuration of wave springs, 15 and 19 which
provide for operationally acceptable force and deflection for a
given free height of the springs. The compression wave springs of
the preferred embodiment of this invention could be replaced with
multi turn wave springs which do not employ flat shim ends but
rather rely on the use of flat end plates in combination with
ordinary wave springs.
[0027] The cylindrical countersunk volumes 11A and 11B are designed
for slidably accepting the first and second shim ends 15A and 15B
of wave spring 15, respectively, in heel region 8C. When fully
inserted, the flat shim ends 15A and 15B of wave spring 15 are held
in firm mechanical contact with the closed ends of cylindrical
countersunk volumes 11A and 11B, respectively.
[0028] The region of shoe sole assembly 4 of the SCS 2 that is
normally proximate the metatarsal region of the foot likewise
having surfaces 10A and 10B (see FIGS. 1 and 4) containing counter
sunk cylindrical volumes 16a and 16b (not shown) for slidably
accepting in the following order the first shim end 19A and the
second shim end 19B (not shown), respectively, of wave spring 19.
When fully inserted the shim ends 19A and 19B of wave springs 19
are in mechanical contact with the closed end portions of
cylindrical volumes 16a and 16b, respectively. The surfaces 8A and
8B are mechanically held in a manner so as to provide minimal
compressive loading on the shim ends 15A and 15B of wave spring 15
by transparent strip 22 (see FIG. 4) which is connected thereto by
adhesive. Similarly, transparent Strip 28 (see FIG. 4) when
adhesively attached to the surfaces 10A and 10B, provide a slight
compressive load on shim ends 19A and 19B of wave spring 19. In
addition to sealing vacuities 6 and 7 from the environment, strips
22 and 28 provide some lateral stability for the users of the SCS
2. It should be apparent that the strips 22 and 28 could also be
made from a number of various materials. In FIG. 1, the upper
portion 5 of the SCS 2 is made of high strength synthetic fabric.
The materials that comprise the SCS 2 are not limited to only those
mentioned in this disclosure. Any number of materials can be used
in the manufacturing of the shoes of this invention. The
cylindrical volumes 11A and 11B and 16a and 16b along with
transparent strips 22 and 28 provide for retention and vertical
stabilization of the wave springs 15 and 19 when they are inserted
into vacuities 6 and 7 respectively.
[0029] Referring to FIG. 1, the front end 29, rear end 30 and
middle region 32 of the shoe sole assembly 4 of the SCS 2 can be
designed to provide retentive support for wave springs 15 and 19
that augments support provided by transparent strips 22 and 28.
Such retentive support can consist of strips that connect the shoe
sole assembly 4 to the upper shoe portion 5. In FIG. 1, wave
springs 15 and 19 are shown as deployed in vacuities 6 and 7 in
shoe sole assembly 4 which is attached to shoe upper portion 5. The
cross sectional view in FIG. 2 shows interior wave spring
compression limiters 36 and 38 which are integral parts of
cylindrical countersunk volumes 11A and 11B respectively. That is,
the compression limiter's outer dimensions define the inner
diameters of countersunk volumes 11A and 11B, respectively.
[0030] The opposing spring compression limiters 36 and 38 (see
FIGS. 2 and 4 ) are separated by extended waves spring 15 whose
solid height when fully compressed by the strike force of the foot
of a user is less than the linear distance in the vertical
direction between spring compression limiters 36 and 38. The
heights of compression limiters 36 and 38 are prescribed by the
depth of the countersunk cylindrical volumes 11A and 11B in
surfaces 8A and 8B, respectively. In the shoes of the present
invention, the distance between the terminal ends of compression
limiters 36 and 38 were set at 12 mm. The heights of spring
compression limiters 36 and 38 are related mathematically to the
spring constant of the wave spring and the mass of the user and are
chosen such that the wave spring 15 can not be compressed to its
solid height during use. Accordingly, because of the force
generated at the portion of shoe sole assembly 4 of the SCS 2 that
is normally proximate the metatarsal of the foot during normal use,
the distance between the terminal ends of spring compression
limiters 42 and 44 is set at 9 mm. The distance between spring
compression limiters 42 and 44 and the spring constant of wave
spring 19 were selected such that the force generated, when the
first surface of shoe sole assembly 4 opposite the ball of the foot
contacts a surface while running, cannot compress wave spring 19 to
its solid height.
[0031] It should be obvious to one skilled in the art that,
depending on the weight of the user, the prescribed distances
between the terminal ends spring compression limiters 36 and 38 as
well as 42 and 44 will vary. In the present invention, the
vacuities 6 and 7 of shoe sole assembly 4 were formed by splitting
middle sole 4B into two substantially equal slabs forwardly from
the heel area toward the toe of the shoe. The cylindrical
countersunk volumes 11A and 11B and 16a and 16b were formed by
machining, at the proper locations and depths in foam polymeric
material of middle sole 4B. The combined depths of cylindrical
countersunk volumes 11A and 11B and 16a and 16b were selected such
that the heights of wave springs 15 and 19 would create vacuities 6
and 7 at those regions of 4B, when inserted therein. Once wave
springs 15 and 19 were inserted in the machined cylindrical
countersunk volumes, the split portions of foamed polymeric
material of middle sole 4B were adhesively reattached at the middle
region of shoe sole assembly 4. And, the vacuities 6 and 7 are
sealed by strips 22 and 28 respectively. The strips 22 and 28 were
attached by adhesive to the shoe sole assembly 4 at the heel and
ball of the foot regions of the SCS 2. The foamed polymeric
material of middle sole 4B could be made from any number of
materials such as polyurethane.
[0032] The method for forming the vacuities 6 and 7 and fixing the
wave springs 15 and 19 in the middle sole 4B of SCS 2 in the
present invention was as discussed above. However, it is obvious to
one skilled in the art that the vacuities and spring retention
methods could be formed by any number of manufacturing techniques
available to the shoe industry such as the use of the molding
process and the springs inserted into the assembled shoe sole. Or
the complete shoe sole-spring assembly could be made in one single
continuous process.
[0033] The wave spring 15 which primarily provides cushioning
during foot strikes has a free height selected to be greater than
that of wave spring 19 which provides primarily liftoff force to
the foot of a wearer.
[0034] Even though the wave springs 15 and 19 used in the shoes of
this invention are metallic in construction, it should be obvious
to one skilled in the art that the material of the wave springs is
not solely limited to metals and that a wide variety of other
materials could be used as well. Likewise, the materials used in
the other parts of the shoe may be made from any multitude of
materials commonly used in the art. While the shoe of this
invention use single leaf crest-to-crest wave springs, it could
have employed interlaced wave springs described in U.S. Pat. No.
5,639,074 or commercially available nested wave springs. The
interlaced and nested wave springs like the crest-to-crest wave
springs provide the primary desirable characteristics of
crest-to-crest wave springs important to the shoe of the invention.
That is, like crest-to-crest wave springs, interlaced and nested
wave springs provide maximum force and deflection for a given
unloaded spring height.
[0035] FIG. 5 shows a second embodiment of the shoes of this
invention. In FIGS. 5 and 6, wave springs 50 and 52 are mounted in
vacuity 54 with their first and second terminal shim ends 56 and 58
mounted in U-shaped plastic receiving clip 60, which contain
protrusions 64 as shown in FIG. 7 which slidably accepts the first
and second terminal shim ends 56 and 58 of wave springs 50 and 52
until firm mechanical contact is achieved between the shim ends 56
and 58 and the closed ends 63 of protrusions 64 of U-shaped
receiving plate 60. The U-shaped plastic receiving clip 60
containing wave springs 50 and 52 are inserted into vacuity 54
where it is attached as by adhesive to the plain interior surfaces
53A and 53B of vacuity 54 in heel area of foamed polymeric material
4B' of shoe sole assembly 4'. The U-shaped plastic-receiving clip
60 is designed to have one pair of cylindrically shaped compression
limiters 65 associated with each wave spring. One of the terminal
ends of each of the compression limiters 65 being adhesively
attached to each of the opposing inner surfaces of clip 60 at the
diametrical centers of protrusions 64 by adhesive, as shown in FIG.
7. The U-shaped plastic receiving clip 60 of this second embodiment
of the shoes of this invention could be replaced by two plastic
plates containing protrusions for slidably accepting the shim ends
of one or a multiplicity of wave springs. The vacuity 54 is sealed
as shown in FIGS. 5 and 6 with extensionable plastic 69 which
provide for strength of the SCS 2' in the lateral or side to side
direction during use.
[0036] Vacuity 66 is located in the metatarsal region of shoe sole
assembly 4'. Plastic plates 68 and 70 having protrusions 72
substantially identical to protrusions 64 of FIG. 7 on their first
surface into which the first and second shim ends 73A and 73B of
wave springs 73 and the first and second shim ends 74A and 74B (not
shown) of wave spring 74 (FIG. 6) are slidably inserted. The
plastic plates 68 and 70, in addition to the first surfaces, have
substantially parallel second surfaces. The assembled unit
consisting of plastic plates 68 and 70, protrusions 72 and wave
springs 73 and 74 are inserted into vacuity 66 of shoe sole
assembly 4'. The second surfaces of plastic plates 68 and 70, with
wave springs 73 and 74 inserted therebetween, are attached to the
plain interior surfaces 75A and 75B of vacuity 66 by adhesive. The
plates 68 and 70 are designed to accept with minimal resistance
compression limiters 78 which are attached to diametrical centers
of plates 68 and 70 in a manner similar to that of compression
limiters 65 to plates 68 and 70. The compression limiters 78 serve
to limit the amount of compression that wave springs 73 and 74 can
undergo during use. The vacuity 66 is sealed with extesionable
plastic 76.
[0037] It should be obvious to a person of ordinary skill in the
art that more than two wave springs could be employed in each of
the heel and metatarsal regions the shoes of this invention. A
compression limiter, in this second embodiment, is associated with
each wave spring. However, one or more strategically positioned
pairs of regional compression limiters could be used to limit the
compression of a plurality wave springs.
[0038] The spring-cushioned shoe of the second embodiment of this
invention contains opposing plates, which are separated by
intervening foam material shown in FIG. 5. The plastic plates could
also be held firmly by friction or other mechanical means other
than the previous mentioned adhesive, for slidable insertion into,
and removal from, the shoe sole assembly 4' to accommodate
replacing the wave springs with other wave springs of different
spring rates. Furthermore, the plastic plates could be concatenated
giving rise to a plastic member that extends from the heel area to
the ball of the foot area of the shoe sole assembly. A shoe sole
assembly designed to accept the plastic member could be equipped
with a single vacuity that like the plastic member that extends the
full length of the shoe sole assembly.
[0039] The wave springs used in the preferred embodiment of the
invention are made of spring steel with inner and outer diameters,
transverse thicknesses, peak and trough heights and quantities
chosen so as to provide spring rates for wave spring 15 and 19 of
600 lb/in and 500 lb/in respectively.
[0040] The critical design parameters and materials of the wave
springs could be selected so as to provide springs of different
spring forces and other characteristics. For example, other
metallic and non-metallic materials, polymers, and composites could
be selected for different weight and strength characteristics.
Also, the design parameters of the wave springs may be altered to
provide varying strength, deflection, and load characteristics.
Further, the embodiment of this invention is described in terms of
a single cushion shoe. It should be obvious that the companion
cushion shoe will be of identical design and construction.
[0041] The operation of the SCS 2 will now be explained in view of
the shoe of FIG. 1. When a pair of spring cushioned shoes is placed
in use by a user, for example a runner, the region of the shoe
containing wave spring 15 strikes the running surface first. The
strike force applied by the calcaneus portion of the foot
compresses the wave spring to a prescribed height before the foot
is brought to rest and the body mass is dynamically transferred to
the metatarsal region of the foot in contact with the surface where
the wave spring 19 becomes compressed. When the body mass is
transferred to the metatarsal region of the foot, wave spring 15
which was in the initial footstrike undergoes a compress-recoil
cycle. As the user lifts the metatarsal region of the foot, energy
is transferred to this region as wave spring 19 recoils. Thus, wave
springs 15 and 19 both provide cushioning and energy return to the
user of the SCS 2.
[0042] During footstrike (whether from jumping or running), peak
forces of several times the body weight can be imparted to the wave
springs. We can assume that an average user of the shoes would
weigh 165 lbs. Therefore, average peak forces greater than 300
lb.sub.f can be imparted to the wave springs. Hence, the previous
mentioned spring rates could be used for a 165-lb person.
[0043] Wave springs are ideal for use in this limited space
application. Conventional spring methods are inferior in shoe
cushioning applications because of the limited combination of
force, deflection, and space requirements.
[0044] While a preferred embodiment has been shown and described,
it will be understood that it is not intended to limit the
disclosure, but rather it is intended to cover all modifications
and alternate methods falling within the spirit and the scope of
the invention as defined in the appended claims.
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