U.S. patent application number 10/610629 was filed with the patent office on 2004-03-04 for full energy return shoe.
Invention is credited to Hogan, Bartholomew P., Rennex, Brian G..
Application Number | 20040040180 10/610629 |
Document ID | / |
Family ID | 34197353 |
Filed Date | 2004-03-04 |
United States Patent
Application |
20040040180 |
Kind Code |
A1 |
Rennex, Brian G. ; et
al. |
March 4, 2004 |
Full energy return shoe
Abstract
This invention is a full energy return shoe. It comprises
various embodiments of a "full energy return" linkage attached to
upper and lower sole plates along their full lengths. This linkage
constrains relative motion of the upper and lower plates by
limiting or eliminating relative tilting and by controlling or
eliminating relative longitudinal motion. These constraints result
in foot impact energy being stored in springs irregardless of
whether the force acts on the front or rear of the sole. That is,
both toe and heel impact energy are used or returned during
toe-off. These spring are coupled to links or vertices of the
linkage and are designed to achieve an optimal ground reaction
force curve of the shoe on the ground--varying from linear to
constant curves. Useful features include a push-off frame to allow
heel lift and a flex-rigger to prevent sprained ankles.
Inventors: |
Rennex, Brian G.;
(Rockville, MD) ; Hogan, Bartholomew P.;
(Rockville, MD) |
Correspondence
Address: |
Brian Rennex
POB 10693
Rockville
MD
20849
US
|
Family ID: |
34197353 |
Appl. No.: |
10/610629 |
Filed: |
July 2, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10610629 |
Jul 2, 2003 |
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10026797 |
Dec 27, 2001 |
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Current U.S.
Class: |
36/28 ; 36/27;
36/35R |
Current CPC
Class: |
A43B 13/184 20130101;
A43B 13/182 20130101 |
Class at
Publication: |
036/028 ;
036/035.00R; 036/027 |
International
Class: |
A43B 013/28 |
Claims
1. A full energy return shoe sole for walking, running, and jumping
comprising a top sole plate and a bottom sole plate, one or more
full energy return linkages each comprising four or more links
hingeably interconnected at vertices, one or more springs acting
between said links, and a foot attachment means to attach said
p-diamond sole to the foot of a wearer, wherein at least one of
said links is rigidly attached to said top sole and at least one
other of said links is rigidly attached to said bottom sole,
wherein said full energy return linkage provides a full energy
return constraint for said top plate to remain aligned
substantially parallel to said bottom plate along their full
lengths throughout the compression and expansion during the stance
period, wherein said springs absorb the full impact energy imparted
on the ground along the entire length and width of said foot during
the impact period of stance and said springs return said full
impact energy during the thrust period to impel said wearer forward
and upward, wherein any compression force between any portions of
said top sole plate and said bottom sole plate causes all impact
energy to be stored in said springs until the toe-off period,
wherein the heel impact energy is not dissipated by being released
prematurely, before the toe-off period.
2. The full energy return shoe sole of claim 1 wherein said full
energy return linkage can be combination linkage of said full
energy return linkage with additional links, provided said full
energy return constraint is provided by said combination linkage,
wherein said combination linkage can be oriented in various
directions including laterally and longitudinally.
3. The full energy return shoe sole of claim 2 wherein said
combination linkage is a p-diamond linkage comprising four diamond
links hingeably interconnected to form a diamond shape with a top
vertex, a bottom vertex, a front vertex and a rear vertex, a top
length link hingeably connected to said top vertex, a bottom length
link hingeably connected to said bottom vertex, a mid length link
hingeably connected at its front end to said rear vertex, two end
links hingeably connected to each other at the rear end of said
center length link, and a mid-link front vertex guide rigidly
extending along and from said mid length link to make a key
constraint on said front vertex to move along the continuation line
extending along the length of said mid length link.
4. The full energy return shoe sole of claim 2 wherein said
combination linkage is a p-linkage comprising four p-links which
form a parallelogram.
5. The full energy return shoe sole of claim 2 wherein said
combination linkage is a 2p-linkage comprising seven 2p-links which
form two parallelograms with a shared link.
6. The full energy return shoe sole of claim 1 wherein said top
sole plate comprises a push-off means which allows said wearer to
flex his metatarsal joint, push off his toe, and lift his heel as
he rocks forward onto his toe during toe-off, wherein said push-off
means constrains the heel of said wearer to raise and lower
directly above said top sole plate.
7. The full energy return shoe sole of claim 1 wherein the hinges
which connect said links comprise necked hinges which are
monolithic and which flex due to being necked down to a small width
and a flexible material at said hinge.
8. The full energy return shoe sole of claim 1 wherein said springs
and said full energy return linkage provide a substantially
constant curve of the ground reaction force during stance.
9. The full energy return shoe sole of claim 1 wherein said bottom
sole plate comprises a curved bottom.
10. The full energy return shoe sole of claim 1 wherein said space
shoe further comprises elastic outer walls connecting said push-off
frame and said top sole plate with said bottom sole plate.
11. The full energy return shoe sole of claim 1 wherein said bottom
sole plate comprises a flex-rigger, flexibly attached to the sides
of said bottom sole plate so that said flex-rigger can bend or
rotate in the horizontal plane but not in the transverse-vertical
plane, wherein said flex-rigger is biased to stick approximately
straight out to the sides, wherein said flex-rigger is dimensioned
and constructed to resist sideways roll over of said space shoe
which could cause said wearer to sprain his ankle, wherein said
flex-rigger can optionally be compressed inward along its
length.
12. The full energy return shoe sole of claim 1 wherein said space
shoe further comprises a front/back brace leg further comprising a
harness for coupling to a wearer's pelvis, a front hip pivot, a
back hip pivot, a front thigh link pivotly attached to the front of
said harness with said front hip pivot, a back thigh link pivotly
attached to the front of said harness with said back hip pivot, a
front tibia link pivotly attached to the front of said brace foot,
a back tibia link pivotly attached to the back of said brace foot,
a front knee pivot connecting said front thigh link and said front
tibia link, a back knee pivot connecting said back thigh link and
said back tibia link, one or more hyper-extending knee pivot locks
at the locations of said front and back knee pivots to prevent
pivot hyper-extension, an optional back hydraulic knee lock pivotly
attached to said back thigh link and said back tibia link, an
optional front hydraulic knee lock pivotly attached to said front
thigh link and said front tibia link, a front ankle pivot for the
connection of said front tibia link to said upper frame, a back
ankle pivot for the connection of said back tibia link to said
upper frame, a knee cross link connecting said front knee pivot
with said back knee pivot, wherein said front and back hip pivots
are located approximately above the center of each leg, wherein the
front and back locations of said brace leg elements prevents
interference with said runner's legs.
13. The full energy return shoe sole of claim 12 wherein said
harness comprises a front/back pack extension further comprising a
front pack-frame pivot at the front of said harness, a back
pack-frame pivot at the back of said harness, a front pack frame
attached to the front of said harness via said front pack-frame
pivot, a back pack frame attached to the back of said harness via
said back pack-frame pivot, pack straps, a front pack secured to
said front pack frame be said pack straps, and back pack secured to
said back pack frame be said pack straps, wherein said brace legs
continuously support said front and back packs as said wearer walks
or runs.
14. The full energy return shoe sole of claim 1 wherein said full
energy return shoe sole provides energy return for a prosthetic
leg, wherein said full energy return shoe sole further comprises a
pylon attached to said upper frame, wherein said pylon attaches to
the stump of an amputee's leg.
15. The full energy return shoe sole of claim 1 which further
comprises a bow shoe for use by a runner, wherein said spring
system comprises a bow spring located above said upper frame and
hingeably connected to said top sole plate, a leg attachment means
for attaching said bow spring to the leg of said runner, a
suspension system connecting the top of said bow spring to said
lower sole plate, wherein the force of both the runner's toe and
heel cause said bow spring to be loaded throughout foot-strike,
wherein heel impact energy is not returned prematurely at the
beginning of to push-off, but rather is returned optimally during
toe-off during the latter part of push-off.
16. The full energy return shoe sole of claim 15 wherein said
suspension system comprises one or more ankle-pivot supports
rigidly attached to said ground plate and extending around and
above the level of the foot of said runner, one or more ankle-pivot
housings rigidly attached to said ankle-pivot support and housing
an ankle pivot, one or more cords attached to said shoe plate and
passing around the foot of said runner and through said ankle-pivot
housings, and a cord guide to constrain said cords to the location
of said ankle-pivot.
17. The full energy return shoe sole of claim 16 wherein said
suspension system further comprises a shin-level bow spring
assembly comprising a bow spring pivotly attached to said
ankle-pivot housing, a bow guide pivotly attached to said
ankle-pivot housing and to the top of said bow spring, wherein said
bow guide changes length telescopically, a shin slider slidingly
attached to the top of said bow guide, and a shin strap for
attaching said shin slider to the shin of said runner, wherein said
cords extend to connect to the top of said bow spring, wherein the
impact force of said runner's foot on said shoe plate loads said
bow spring via said cords.
18. The full energy return shoe sole of claim 1 wherein said bottom
sole plate comprises a back-heel and a padded leg brace, wherein
said back heel is a rigid, upwardly curving extension of said lower
frame, wherein the deceleration of the runner's center of mass at
heel strike is reduced by decreasing the effective angle of the
line of force between the runner's center of mass and the initial
point of contacts of said back-heel with the ground, wherein said
padded leg brace impinges the leg of said runner above the ankle to
prevent hyper plantar flexion at heel strike.
19. The full energy return shoe sole of claim 2 wherein said
combination linkage is a arbitrary length 4-link linkage comprising
four arbitrary length links hingeably interconnected.
Description
BACKGROUND
[0001] This application is a CIP of U.S. patent application Ser.
No. 10/026,797 filed Dec. 27, 2001. This invention is a full energy
return shoe. It comprises various embodiments of a "full energy
return" linkage, referred to herein a sole linkage, attached to
upper and lower sole plates along their full lengths. This linkage
constrains relative motion of the upper and lower plates by
limiting or eliminating relative tilting and by controlling or
eliminating relative longitudinal motion. These constraints result
in foot impact energy being stored in springs irregardless of
whether the force acts on the front or rear of the sole. That is,
both toe and heel impact energy are used or returned during
toe-off. These spring are coupled to links or vertices of the
linkage and are designed to achieve an optimal ground reaction
force curve of the shoe on the ground--varying from linear to
constant curves. Useful features include a push-off frame to allow
heel lift and a flex-rigger to prevent sprained ankles.
[0002] The first embodiment of the space shoe is called a space
shoe because most of the skeletal sole is free space rather than a
solid, foam-filled structure. The springs of the space shoe act
directly between elements of the sole linkage which acts on the
ground plate and the shoe plate; that is, these springs are located
at shoe or sole level. The second embodiment of the invention is
called a bow shoe; its bow spring is located up to the shin
level.
[0003] The space shoe provides for the following improvements which
will referred to in the discussion of prior art as S1, S2, and S3.
(S1) It has an improved mechanism to capture both heel and toe
impact energy and return all impact energy through the toe during
the latter part of toe-off. The extent of the sole linkage along
the full sole length is key and distinguishes it from prior art.
(S2) It provides for optimal stability by constraining the upper
shoe plate to have minimal or no relative longitudinal or tilting
motion with respect to the lower sole plate--via the sole linkage.
Improvement (S2) is referred to herein as sole tilting/sliding.
Improvement (S3) is that a natural running action is allowed--where
this running action comprises both a natural roll-over from heel to
toe and a push-off--with the wearer's metatarsal joint freely
flexing and the heel lifting into the air during toe-off.
[0004] Seven categories of prior shoe art with springs or relevant
features are listed below. Examples of each category will be given,
along with limitations overcome by the space shoe improvements
which improvements will be referred to by the numbers S1 to S3
mentioned above. The first category has multiple springs located
throughout the sole or only in the heel. Examples include U.S. Pat.
No. 5,621,984 of Hsieh and U.S. Pat. No. 5,337,492 of Anderie.
Space-shoe improvements S1, S2, and S3 apply to this category which
prior art notably permits sole tilting (S3) in a see-saw manner
which does not couple spring energy for toe thrust and which
dissipates heel impact energy in mid-stance (S1). With regard to
improvement (S1), as the wearer's heel lifts to push-off, the
prior-art heel springs release their energy prematurely, the
wearer's knee bends and his ankle dorsi-flexes during which time
the heel impact energy is largely dissipated. In fact, for this
heel impact energy to efficiently propel the wearer up and forward,
it must act through the wearer's toe during the latter part of
toe-off.
[0005] The second category of "springs in soles" prior art has a
means to captures all of the heel impact energy for energy return
at toe-off. An example is U.S. Pat. No. 4,936,03 of Rennex.
Improvements (S2 & S3) apply, and the space-shoe mechanism to
achieve improvement (S1) is considerably simpler and cheaper. The
third category of "springs in soles" prior art has a linkage to
constrain a compressible sole as a spring stores impact energy.
Examples include U.S. Pat. No. 4,534,124 of Schnell, U.S. Pat. No.
5,896,679 of Baldwin, U.S. Pat. No. 5,701,685 of Pezza. Space-shoe
improvements (S2 and S3) apply to Schnell and Pezza. Improvements
(S1, S2, and S3) apply to Baldwin.
[0006] A third category of relevant prior art does not actually
have springs in the soles. Rather, these patents do provide means
for the wearer to flex their metatarsal joint and push off their
toe. U.S. Pat. No. 4,400,894 of Erlich, U.S. Pat. No. 5,926,975 of
Goodman, and U.S. Pat. No. 5,384,973 of Lyden all feature a
narrowing of a conventional, solid sole under the metatarsal joint,
and there are many other examples of this solution. U.S. Pat. No.
6,079,126 of Olszewski uses the just-mentioned "narrowing" solution
as well as another solution where a conventional, solid sole is
split and the upper section lifts with the wearer's heel. A U.S.
Pat. No. 5,282,325 of Beyl also teaches a split sole with a torsion
spring in the heel.
[0007] The current patent also provides for the wearer to flex his
metatarsal joint and push off his toe--in a variety of ways.
However, the sole structure of the space shoe is distinct--in that
it comprises a linkage between plates, instead of the conventional,
solid sole of the just-mentioned prior art. That is, even though
the "toe-flex" function is the same, the structure and designs of
the current patent are quite different and novel, and the general
idea of a means for toe-flexing is old in the art.
[0008] With reference to the second embodiment of the invention,
namely the bow shoe, the above improvements (S1, S2, and S3) still
apply--along with some additional improvements labeled "B" for bow
shoe. (B1) The bow shoe minimizes weight at the foot for improved
energy efficiency. (B2) It uses bow springs to achieve a constant
force curve. (B3) It permits optimally few, long, and light bow
springs. (B4) It provides for optimal stability by minimizing the
unweighted sole thickness.
[0009] The fourth category of "springs in soles" prior art has a
spring and suspension mechanism in the heel. An example is U.S.
Pat. No. 6,115,942 of Paradis with a bow spring. Improvements (S1,
S2, B3, and B4) apply to this patent. Another example is U.S. Pat.
No. 6,131,309 of Walsh with improvements (S1-S3and B1, B3 and B4)
applicable. The fifth category has a curved ground support
hingeably connected in front and in back to the shoe and a single
spring in the center. An example is UK Patent #GB2,179,235 of
Waldron. Improvements (S1-S3 and B1-B4) apply to this category. The
sixth category of has a linkage to constrain a compressible sole as
a spring stores only heel impact energy. Examples include U.S. Pat.
No. 4,534,124 of Schnell, U.S. Pat. No. 5,896,679 of Baldwin, U.S.
Pat. No. 5,701,685 of Pezza, U.S. Pat. No. 1,613,538 of Schad, U.S.
Pat. No. 5,464,380 of Ikeda, U.S. Pat. No. 3,205,596 of
Hoffineister, U.S. Pat. No. 6,553,692 of Chung, and U.S. Pat. No.
6,115,943 of Gyr
[0010] Improvements (S2, S3 and B1-B4) apply to Schnell and Pezza.
Improvements (S1-S3 and B1-B4) apply to Baldwin. Improvements
(S1-S3) apply to Schad. Improvements (S1 and S3) apply to Ikeda,
Hoffineister, and Chung. Ikeda does use side-ways-opening hinged
links to constrain longitudinal relative plate motion, but in a
manner distinct from the current sole linkage. Hoffineister uses
multiple, connected diamond links to prevent sole tilting, but his
linkage requires that the upper and lower hinges, which bear
considerable weight, slide in slots. This disadvantage is overcome
in the current sole linkage which does not have weight-bearing
sliding bearings, which fact makes it a distinct linkage from that
of Hoffineister. Chung uses lateral "x" hinged links which again
present difficulties with weighted sliding on the plates of the top
and bottom ends of the links, and Chung's linkage both is distinct
from the current sole linkage and is confined to the heel region.
Gyr does disclose a parallelogram linkage, but only in the heel and
without loading the linkage so as to achieve a optimal or constant
force curve. Also, the relative longitudinal motion of the bottom
of Gyr's linkage with respect to the forefoot win cause significant
friction losses.
[0011] The seventh category uses a linkage to connect the toe of a
shoe to the mid-section of a bow spring, the bottom of which
contacts the ground. A commercial product of ALANSportartikel,
address: GmbH Grafratherstrasse 53, 82288 Kottgeisering/Germany,
marketed under the brand name of "Powerskip" and referenced by
their website, http://www.powerskip.de, is the only example of this
category. Improvement (S3) applies because the force curve is not
as constant as for an axially-loaded bow spring, and improvements
B3 and B4 apply. The most notable improvement is (B2) because the
foot of the wearer of "Powerskip" is a substantial distance above
the ground even when the bow spring is fully compressed.
[0012] Finally, with regard to the flex-rigger of the current
patent for prevention of sprained ankles, U.S. Pat. No. 5,875,569
of Dupree discloses a small tab on the outside of a sole, which
does not flex forward and backward to avoid tripping and which does
not project as far to the side (given more protection) as is made
possible by the flexing action of the flex-rigger. With regard to
the leg-braced back-heel of the current patent, U.S. Pat. No.
4,238,894 of Evans discloses a back extension which does not have
the leg brace of the current patent for prevention of hyper plantar
flexion.
SUMMARY
[0013] With reference to the space shoe, in both space shoe and
bow-shoe embodiments, the key feature is a compressible sole
comprising a sole linkage which constrains the upper shoe plate not
to tilt as it moves vertically up and down with respect to the
ground plate. Another feature is a push-off means which allows the
wearer to freely push off her toe. Another feature is that a
minimal number of springs and stops (even one) of any kind can be
used (without need of a spring guide). These springs and stops can
easily be modular and replaceable to fit the performance
requirements of an individual for walking and running. Another
feature is a back-flexing outrigger, called herein a "flex-rigger,"
to prevent sprained ankles; the flex-rigger can be used not only
with the space shoes, but also as a retrofit or an integral part of
conventional shoes or boots. Another feature is a curved extension
extending backward from the bottom of the sole heel; this is called
herein a "leg-braced back-heel." The back-heel minimizes the
deceleration of the user's center of mass at heel-strike by
reducing the effective angle (backward, off-vertical) of the leg
support, and the leg brace prevents hyper plantar flexion at heel
strike. The back-heel can also as a retrofit or an integral part of
conventional shoes or boots.
[0014] The advantages of the space shoe include: the sole can be
very thick (2-6 inches) thereby make a wearer taller and enhancing
her stride; even when the sole is thick, the wearer's foot rolls
over from heel to toe naturally; the wearer pushes off naturally;
the shoe is energy-efficient in that it returns maximum impact
energy (due to both heel impact and toe impact) to the wearer
during thrust at toe-off when it is best utilized; the shoe is
light-weight and cheap to manufacture; there are spring systems
which provide for a constant force curve, instead of a linear force
curve, thereby permitting faster running for a given maximum force,
thereby reducing impact injuries; since the surface in contact with
the foot is very thin, it is easy to ventilate the foot; this
foot-contact can be shaped as a foot orthotic; and the sole
thickness (1" to >6") and area can easily be changed due to the
modular construction.
[0015] A critical insight motivating the (full energy return) sole
linkage is that, in order for heel impact energy to efficiently
propel the runner up and forward, it must act through the runner's
toe during the latter part of toe-off. The sole linkage controls
tilting of the compressible sole, and this constraint also results
in heel impact energy to be returned at toe-off. Another
performance enhancement in terms of energy efficiency results from
the fact that the sole linkage can be made very thick. This allows
the wearer to minimize knee flexion in both walking and running.
With reference to the bow-shoe embodiment only, one key feature is
a bow spring to achieve a constant spring force curve which doubles
the potential energy storage in a sole of a given thickness.
Another key feature is a suspension system in which a bow spring is
loaded by full foot impact--both by the heel and the toe. This
suspension system permits the location the bow spring above the
foot at the shin or thigh level to minimize the device weight at
foot level--thereby improving energy efficiency. Also, the use of
an linkage allows the sole components to be optimally (skeletally)
light. Another improvement is related to the constant force curve,
referred to as a buckling curve, achievable with bow springs. This
allows a safe threshold force level to be set, and twice as much
energy can be stored for a given sole thickness as with a linear
spring. Also, bow springs can be more than 90% energy efficient. A
consequence of the anti-tilt feature inherent in the sole linkage
is that a spring located anywhere in the sole resists sole
compression at both the toe section and the heel section. This
means that one or two springs or stops suffice, and modular design
makes it a simple matter to change springs to tune the bow shoe to
an individual's weight and gait and to change shoe and ground
plates for different size feet. Another improvement is that the bow
shoe provides for optimal stability by minimizing the unweighted
sole thickness--by virtue of the remote location of the bow spring
above the foot level. That is, since the bow springs are not
located in the sole, the sole can be fully compressed. Finally, the
sole linkage can be manufactured very cheaply.
[0016] Other applications include a spring/foot component of a
walking/running brace or of a backpack-supporting brace for walking
and running and for use with prostheses and robotics.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 shows views of the main invention, a non-tilting
compressible structure called p-diamond.
[0018] FIG. 2 shows a side view of a p-diamond linkage indicating
how lengthwise springs with the proper hard force curve can be used
to achieve a constant force curve, as well as mirrored and
vertically stacked configurations of p-diamonds.
[0019] FIG. 3 shows schematic side and front views of the space
shoe showing the compressible p-diamond sole.
[0020] FIG. 4 is a schematic side view of the p-diamond sole with
necked link hinges.
[0021] FIG. 5 is a schematic side view of examples of necked link
hinges.
[0022] FIG. 6 shows means to attach a foot to the space shoe and a
schematic side view of the space shoe showing elastic walls.
[0023] FIG. 7 is a schematic side view of the space shoe showing an
elevated heel on the push-off frame and a schematic front view of
the space shoe showing various profiles for the p-diamond sole.
[0024] FIG. 8 shows a schematic front view of the space shoe
showing back-flexing outriggers to prevent sprained ankles and a
schematic top view of the space shoe showing various back-flexing
outriggers to prevent sprained ankles.
[0025] FIG. 9 is a schematic side view of the space shoe showing
various designs of push-off frames.
[0026] FIG. 10 is a schematic top view of the space shoe showing a
delayed heel-lifter in the spring system to lift the runner's heel
during the latter part of toe-off.
[0027] FIG. 11 shows an application of the p-diamond invention to
running braces.
[0028] FIG. 12 shows an application of the p-diamond invention to
leg prostheses
[0029] FIG. 13 is a schematic side view of the bow shoe embodiment,
with a shin-level bow spring and a compressible p-diamond sole.
[0030] FIG. 13 is a schematic front view of the bow shoe
embodiment, with a shin-level bow spring and a compressible
p-diamond sole.
[0031] FIG. 15 shows side views of a p-linkage and a simplified
presentation called herein a "line-link view" where lines represent
links.
[0032] FIG. 16 shows line-link side views of a 2p-linkage, first
with symmetric link lengths and second with asymmetric link
lengths.
[0033] FIG. 17 shows Line-link side views of a one-spring leaf
linkage and a two-spring leaf linkage.
[0034] FIG. 18 shows a line-Link side view of a p-diamond and a
half-height p-diamond.
[0035] FIG. 19 shows Line-Link side views other configurations of
the p-diamond.
DETAILED DESCRIPTION OF THE INVENTION
[0036] FIG. 1 shows views of the main invention, a non-tilting
compressible structure called p-diamond 11. Side-view FIGS. 1a and
1b show p-diamond 11 expanded and compressed. FIG. 1c is a front
view and FIG. 1d is a top view. P-diamond 11 comprises one or more
(two here) p-diamond linkages 9, rigidly connected by cross beams
13, and optionally covered by cover plates 21 on the top and the
bottom. P-diamond linkage 9 comprises four diamond links 10, one
top length link 23, one center length link 24, one bottom length
link 25, and two end links 14--all of which are hingeably connected
in the depicted configuration by link hinges 16. Top length link 23
and bottom length 25 optionally extend beyond Link hinges 16 on
either end, but the functional parts for p-diamond linkage 9, that
cause the critical motion constraint of p-diamond linkage 9 to move
with only one degree of freedom, requires only the parts between
the link hinges 16. The other required constraint is that mid-link
front vertex guide 71, rigidly attached to center length link 24
and extending horizontally to the left in FIG. 1b, guides front mid
link hinge 16 to follow a horizontal path as p-diamond linkage 9
collapses and expands. That is, this guided constraint ensures that
center length link 24 stays precisely in the center between top
length link 23 and bottom length Link 25. As long as this center
position is maintained the bearing force of front mid link hinge 16
on mid-link front vertex guide 71 is minimal. This minimal guiding
force is a key advantage of p-diamond linkage 9 over linkages found
in the prior art.
[0037] In total, all these links form an 8-bar linkage which
constrains upper frame 6 to move vertically (with no tilting) with
respect to lower frame 4. In this embodiment, upper frame 6
comprises two top length links 23, cross beams 13 at the top, and
cover plate 21 at the top. Likewise, lower frame 4 comprises two
bottom length links 25, cross beams 13 at the bottom, and cover
plate 21 at the bottom.
[0038] FIG. 1a shows lengthwise spring 57 and pre-bow spring 51
which resist any compression force on p-diamond 11; vertical
springs 19 also resist external compression. An external
compression force can be exerted at any point on and between the
areas of upper frame 6 and lower frame 4. At the same time an
expansion force can be exerted at any point on and between the
areas of upper frame 6 and lower frame 4. Even though the
compressive and expansive forces are not located in the same place,
upper frame 6 will not tilt with respect to lower frame 4. This is
the key feature of the p-diamond invention. The term "p-diamond"
refers to the fact that the linkage comprises overlapping
parallelograms and diamonds. The value of the invention is that
this is the simplest structure using only hinges and a
minimal-force guide to achieve this particular constraint of one
degree of motion, and hinges are the cheapest, lightest, most
robust means to achieve guiding of spring mechanisms in many
applications.
[0039] FIG. 1 actually depicts several variations of spring
systems. FIG. 1a shows lengthwise spring 57 (helical) acting
between 1) the center cross bar 17 located at the cross beam at
link hinge 16 connecting the outside (left) pair of diamond links
10 and 2) the center cross bar 17 between adjacent center length
links 24. Note this second location could be anywhere along center
length links 24. Diamond tether 59 limits the amount of
compression. FIG. 1b shows the alternative of a generic vertical
spring 19 resisting compression and stop 44 limiting compression.
These can be helical springs 48 or spiral helical springs 50 (which
can compress to the wire thickness).
[0040] FIG. 1c, the front view, shows the locations of vertical
spring 19 and stop 44, located in this case between the adjacent
p-diamond linkages 9. In dashed lines, the location of center cross
bar 17 is shown--for when a lengthwise spring 57 is used. Top view
FIG. 1d shows a pre-bent bow 51 acting (in tension to resist
compression) between two center cross bars 17. Also shown here is
how cover plate 21 covers the frame work comprising top length link
23 and cross beams 13. Cover plate 21 is optional and upper frame 6
or lower frame 4 could alternatively be anything from a simple
plate to a molded and highly optimized covered, pocketed
framework.
[0041] It is understood that any type of spring deemed useful can
be used, and these may act in compression or tension between
vertices or locations along links. Since p-diamond sole 8 guides
upper frame 6 to not tilt or move sideways with respect to lower
frame 4, a minimal numbers or vertical springs, even one, can be
used, and the both the heel and toe impact energy are returned
through the wearer's toe during the latter part of toe-off.
Notably, single or multiple springs and stops of any shape can be
used to achieve any desired travel or compression from very little
to the entire thickness of the unweighted sole. This full thickness
may be only an inch or it may be six inches or more. Other spring
options include tapered serpentine springs and air springs. By
tapering a bow spring in a particular manner, it is possible to get
just the right "hard" force curve where hard means the curve
increases faster than a linear spring.
[0042] FIG. 3a shows a side view of a p-diamond linkage indicating
how lengthwise springs with the proper hard force curve can be used
to achieve a constant force curve. The vertical force exerted by
lengthwise spring 57 can be expressed as the product of the
mechanical advantage, MA, due to the diamond structure, times the
horizontal force, Fx, exerted by lengthwise spring 57. If the
length of diamond link 10 is Ld and the spring rate is K, then
Fy=MA*K*x where x is the change in length of lengthwise spring 57
as each diamond link 10 rotates an angle, a, from
vertical--assuming a linear spring. Also, MA=(cos(a)/sin(a)) and
x=Ld*sin(a). Thus, Fy=Ld*K*cos(a). By using a tension spring
proportional to (1/cos(a)), one can achieve a constant force curve
in which Fy remains approximately constant as p-diamond 9
compresses under a load. Proper construction of a tapered pre-bent
bow 51 (FIG. 1d) will provide a hard curve which can be designed to
give the desired force curve.
[0043] FIGS. 3b and 3c show side views of mirrored and vertically
stacked configurations of p-diamonds. In FIG. 3b, mirrored
p-diamond 26 comprises two mirrored p-diamonds which share both
diamond links 10 and top, center and bottom links length links 23,
24, and 25. In FIG. 3c, vertically stacked p-diamond 27 basically
has an upper p-diamond linkage 9 which shares its bottom length
link 25 with the top length link 23 of the p-diamond linkage below
it. Here, a single bow spring 52 can be guided and compressed by
vertically stacked p-diamond 27. Two or more stages (stacked units)
could be used with vertically stacked p-diamond 27.
[0044] The primary application of the p-diamond invention is space
shoe 2 which is the first embodiment of the space shoe. All initial
space shoe embodiments use p-diamond 11 of FIG. 1 and all of the
features and benefits of this structure discussed above apply. That
is, the basic components and functions of the p-diamond are the
same. Later other linkages will be shown which provide less
constraint, but which can still be functional.
[0045] Neither the spring system nor mid-link front vertex guide 71
are shown sometimes for ease of viewing, e.g. in FIGS. 3a, b, c,
but it should be understood that these are required in an actual
model. FIGS. 3a, 3b, and 3c are schematic side views and FIG. 3d is
a schematic front view of the first embodiment of a space shoe.
FIG. 3a shows heel-strike, FIG. 3b shows mid-stance with p-diamond
sole 8 compressed, and FIG. 3c shows toe-off. Wearer's foot 1 is
confined to the front section of upper frame 6 and to push-off
frame 18 by shoe straps 22.
[0046] Push-off frame 18 is one example of a push-off means, which
achieves the following functions. (1) It always allows the wearer
to flex her metatarsal joint to lift her heel and push off her toe
at toe off. (2) It optionally may prevent the wearer's toe from
twisting out of the foot attachment means at the toe section by
constraining the rear part of the wearer's foot to lift vertically
with respect to the rear part of upper frame 6. (3) It optionally
may lift the rear part of upper frame 6 to contact the wearer's
heel during swing phase. Push-off frame 18 may extend around the
wearer's heel a variable distance above the bottom of the heel or
it may extend only part way back toward the heel. It may also be a
plate located at the bottom of the wearer's heel and mid-foot,
which plate may be have holes or voids of variable size.
[0047] FIG. 3d shows the front view of p-diamond sole 8, and it is
entirely equivalent to FIG. 1c except that the runner's foot 1 is
now attached to cover plate 21 by shoe straps 22. P-diamond sole 8
corresponds to p-diamond 11 in FIG. 1, comprising the same linkage
elements. Here, vertical spring 19 and stop 44 are shown. Optional
push-off frame 18 is pivotally connected to upper frame 6 below or
on the outsides of the location of the metatarsal joint of wearer's
foot 1--thereby allowing the wearer to push off naturally at
toe-off. Lower frame 4 may incorporate ground plate rocker 30
(shown in place of bottom length link 25 in FIG. 3b) and ground
plate curved toe 32 to optimize the energy return of space shoe 2
(by permitting greater forward tilt at toe-off). Also, cover plate
21 need not cover the entire area of lower frame 4; it could simply
be a durable material such as vibram or hard rubber bonded to the
length and cross beam elements of lower frame 4.
[0048] FIG. 4 shows schematic side views of a p-diamond linkage 9
using necked pivots as necked link hinges 15. FIG. 4a shows
p-diamond linkage 9 fully expanded, and FIG. 4b shows p-diamond
linkage 9 partially compressed. FIG. 5a shows a blow-up of the
diamond 4-bar linkage made up of the four diamond links 10 which
are interconnected by necked link hinges 15, which flex easily by
virtue of having a small cross section and by virtue of being made
of a compliant material. Necked-pivot stops 29 can also be used to
limit compression. Necked pivots 15 for rear links 14 and toe hinge
20 are also shown in FIG. 5b. Notably, p-diamond sole 8 can be
cheaply and easily fabricated by stamp cutting out of a sheet or by
using mold technology. FIG. 5c shows another method for a
"necked-down" hinge comprising elastic strip 63 bonded to link beam
65; or, in FIG. 8d, necked tube (which might have a square cross
section) is another possibility. The flexible material might be
fiber composites or nickel-titanium alloys (Nitinol) known to have
high duty cycles for flexing.
[0049] FIGS. 6a and 6b show means to attach a foot to the space
shoe. FIG. 6a shows one of many possible strapping arrangements to
for shoe straps 22 to attach pre-existing shoe 34 to the front
section of upper frame 6 and to the rear section of push-off frame
18 via buckles 36. FIG. 6b shows toe cup 38 and heel cup 40 which
can be used with or without a pre-existing shoe for the same
attachment and which may incorporate further shoe straps 22. Heel
bumper 39 and toe bumper 37 can also be optionally used to confine
pre-existing shoe 34 to the space shoe. The rest of the sole of the
space shoe is not shown here. In this instance, push-off frame 18
is located at the level of the bottom of pre-existing shoe 34 or
wearer's foot 1, and it may extend a variable distance underneath
pre-existing shoe 34 or wearer's foot 1. Also, plate cover 21 here
is shaped like an orthotic to conform to and give arch support to
the bottom of runner's foot 1. Plate cover 21 could optionally be
perforated to improve foot ventilation.
[0050] FIGS. 6c and 6d are schematic front and side views of the
space shoe showing elastic walls 46. These are attached to and
surround p-diamond sole 8, and they may be sufficiently elastic not
to wrinkle even when p-diamond sole 8 is fully compressed. These
could be elastic or transparent. And, they could be used to keep
dirt out of p-diamond sole 8 or to make a fashion statement.
[0051] FIG. 7a is a side view of the space shoe showing elevated
heel 58 which is now an integral part of push-off frame 18, and
showing back-heel 28. This elevated variation is a basis for high
heels or elevator shoes. The improvement here is that push-off is
allowed due to push-off frame 18 and due to the fact that a
substantial part of the increase in height of the wearer of this
space shoe is due to the thickness of p-diamond sole 8. Thus, the
height of elevated heel does not need to be as large to make a
person significantly taller. Another advantage is that this space
shoe is much more comfortable, e.g. than a high heel, since there
is ample arch support, and the wearer's weight is distributed over
the entire foot. The heel elevation can also be realized by
building up the heel part of upper frame 6, or it can be realized
by building up both a push-off frame (18) and upper frame 6.
Back-heel 28 has a circular shape with a radius approximately equal
to the length of the runner's leg. Its purpose is to reduce the
angle back away from vertical at which the effective leg force acts
(defined by the line between the runner's center of mass and the
point of contact between back-heel 28 and the ground)--thereby
reducing the deceleration of the runner's center of mass during
heel strike. Padded back-heel leg brace 95 distinguishes this back
heel from prior art in that it prevents hyper plantar flexion at
the onset of heel strike. A similar extension and brace can be used
in the front to extend stride safely. Another possibility is to
retrofit conventional shoes with back-heels 28.
[0052] FIGS. 7b and 7c show schematic front views of the space shoe
with various profiles for p-diamond sole 8. FIG. 7b shows hourglass
linkage 62, and FIG. 7c shows pedestal linkage 60. The purpose of
these variations is to make a more attractive style which lends
itself to use with high heels. Elastic walls 46 also improve the
appearance of the shoe.
[0053] FIG. 8a is a schematic front view and FIG. 8d is schematic
top view of the space shoe showing back-flexing outriggers called
flex-riggers 81 to prevent sprained ankles. These flex-riggers 81
all are stiff to prevent rotating upwards, but they flex backward
easily to prevent the wearer from tripping. For example, hinged
flex-rigger plungers 80 are hingeably connected to lower frame 4 so
that they can be swept back easily if they hit the other foot or an
impediment on the ground. However, they resist "roll" rotation of
lower frame 4 about a front-back axis, and, hence, they prevent
twisting of the wearer's ankle. That is, they flex easily back and
forward, but not up and down. Flex-rigger spring 84 weakly biases
outrigger 80 to stick out to the side. Another feature, as
demonstrated by the plunger feature in hinged flex-rigger plunger
80, is that a flex-rigger can be designed to give when pushed
directly inward from the side, so as to not damage an object or a
person next to the user. Other means such as pleated frame 83 could
also be used to give in toward the shoe as well as backward and
forward--but not up since the top and bottom sides would not be
pleated. Flex-rigger wands 88 are also shown can also be used.
Necked flex-rigger frames 86 with necked link hinges 15 can be used
provided their depth is large enough to prevent up/down motion.
Necked link hinges 15 permit front/back motion. These flex-riggers
81 can be used just as well with conventional shoes in which case
they are attached to the shoe sole. They could either be
incorporated in the sole as manufactured, or they could be fixably
attached to retrofit the sole of a pre-existing shoe. The methods
of attachment of flex-rigger 81 to lower frame 4 (or to shoe sole
75 of pre-existing shoe 34 in FIG. 7a) would include, but not be
limited to, bonding, riveting, or screwing.
[0054] In addition, flex-rigger 81 could manufactured as an
integral part of the soles for new types of conventional shoes or
for lower frame 4. For retrofitting, FIG. 8b shows a front view of
a shoe retrofit design with top bar 85 rigidly attached to
flex-rigger 81, for structural, anti-tilting strength, and using
snap pins 89 to snap onto pre-existing shoe 85. FIG. 8c shows a
front view of another retrofit design using under bands 91 which
keep flex-rigger 81 tight on pre-existing shoe 34, along with sole
screws 87.
[0055] FIG. 9 is a schematic side view of the space shoe showing
various designs of push-off frames 18. FIG. 18a shows push-off
frame 18 located at a level above the shoe sole 75 and extended
around the back of pre-existing shoe 34. Optional top brace 90 and
optional bottom brace 92 may connect and brace the side elements of
push-off frame 18 as also shown in the top view, FIG. 18f. FIGS.
18b and 18e show side and top views of part-way push-off frame 94
which extends only part way along the rear section of pre-existing
shoe 34. The top view shows optional frame voids 100 which lighten
the weight when push-off frame may extend below pre-existing shoe
34. FIGS. 18c and 18d show side and top views of bottom push-off
frame 98 which extends below pre-existing shoe 34. The top view
shows optional holes 96 and frame voids 100 which lighten the
weight and provide ventilation of the wearer's foot in case no
pre-existing shoe is used.
[0056] FIG. 10 is a schematic top view of the space shoe showing
delayed heel-lifter 140 in the spring system to lift the runner's
heel during the latter part of toe-off. The purpose is to delay the
action of an impact-absorbing spring until the latter part of
toe-off, and this idea can be used with conventional shoes or
boots, in general. The additional benefit is the calf muscle action
to plantar flex the ankle joint (in toe-off) is assisted by delayed
heel lifter, and better running economy can, in principle, be
achieved. Heel-lifter bow 142 is pivotly connected to lower frame 6
and slidingly connected within pawl/bow pivot guide 160, which is
housed in heel-lifter guide frame 144, rigidly attached to lower
frame 4. Also slidingly connected within heel-lifter guide frame
144 are upper frame catch 148 and push-off ratchet 150--both of
which are biased upward by elastic bands 156 via band posts 158.
P-diamond linkage is shown in FIGS. 10a and 10c, but not shown in
FIGS. 10b and 10d due to lack of space. The spring systems shown in
other figures can be used. Heel-lifter bow 142 acts in addition to
those other springs.
[0057] FIG. 10a depicts the time of heel contact. Heel-lifter bow
142 (another type of spring could be used) is loaded as upper frame
catch 148 is caught by two-way pawl (biased in this direction by a
simple spring not shown), and upper frame cord 152 is pulled down
by upper frame 4. FIG. 10b shows full impact. FIG. 10c shows the
early part of heel lift when it is too early for heel-lifter bow to
act effectively. Until this chosen angle of lift of push-off frame
18, upper frame catch has been engaged, preventing heel-lifter bow
142 from straightening. Bar-bias-bar 162, pivotly connected to
push-off frame 18 and constrained within with an inclined step in
width, will serve to bias two-way pawl 146 to disengage upper frame
catch 148 and engage push-off ratchet 150 at this chosen angle as
shown in FIG. 10e. Then, heel-lifter bow 142 is free to lift
push-off frame 18 via push-off cord 154 during the latter part of
toe-off. During swing phase the device returns to the configuration
of FIG. 10a by virtue of heel hugger 101 of FIGS. 19 or 20 and the
not-shown spring to bias two-way pawl counterclockwise.
[0058] The next embodiment or application of the p-diamond
invention is for use with running braces. The p-diamond provides
the spring and the brace foot so that the action of the running
brace is very similar to the action of the runner's leg and foot.
FIG. 11a shows a front view and FIG. 11b a side view of front/back
brace leg 650 in which the pelvic coupling is made directly behind
and in front of the runner's ischial tuberosity (buttock) rather on
the side of the hip. Front hip pivot 678 is pivotly attached to
harness 683 directly above runner's leg 676 in front, and back hip
pivot 680 is pivotly attached to harness 683 directly above
runner's leg 676 in back. Front and back--hip pivots 678 and 680,
knee pivots 660 and 662, and thigh links 652 and 654--and knee
cross link 674 form a four-bar system. Front and back--ankle pivots
670 and 672, knee pivots 660 and 662, and ankle links 670 and
672--and knee cross link 674 form another four-bar system--with
knee pivots 660 and 662 and knee cross link 674 being shared
between these two four-bar systems. The runner's pelvis and/or
harness 683 act as the cross link at the hip level for the upper
four-bar system, and top length link 23 acts as the cross link at
the foot level for the lower four-bar system. These two four-bar
systems are sufficiently distant from runner's leg 676 throughout a
stride as to not interfere with the same. Back hydraulic knee lock
664 is rotatably connected to a back thigh link 654 and back tibia
link 668 so that when a foot trigger (not shown, but
straightforward to implement for one of ordinary skill in the art)
locks back hydraulic knee lock 664 as foot strike, flexion about
back knee pivot 662 is locked. Another knee lock could be used for
front knee pivot 660, but this is not necessary because back knee
pivot 662 is shared by both four-bar systems. That is, when back
knee pivot 662 is locked, both the above-mentioned top and bottom
four-bar systems are converted to three-bar systems, and both
structures are locked. Folding of the upper and lower four-bar
systems with respect to each other is realized as the runner's
weight leans forward. This folding can be enhanced by tethering
front and back knee pivots 660 and 662 to the runner's knee. The
runner's foot can now be coupled to bottom length link 25 at its
front, thereby permitting heel lift during toe-off.
[0059] Note the elements of the p-diamond linkage 9 are the same as
in FIG. 1. The key difference here is that the runner's foot 1 is
now located between the two p-diamond linkages 9, which, in turn,
are rigidly connected in the front and the back by brace cross bars
682. In this way, front/back brace leg 650 supports the runner's
weight in parallel with the runner's leg. Also, lengthwise spring
57 can now be positioned to be outside of p-diamond linkages 9 and
to be curving upward, the runner's foot is not directly above.
Finally, if the one or both knee pivots in FIG. 11 are constrained
from hyper-extending (as is commonly done with above-knee
prostheses), a separate knee lock, such as back hydraulic knee lock
664, can be eliminated since the "constrained hyper-extension knee
lock" naturally locks at heel-strike and naturally starts folding
just before toe-off. Having a separate knee lock allows the runner
to run uphill or to land with a more substantially pre-bent leg,
but this capability is not needed in many applications. This is
even more true for a running brace than for above-knee prostheses,
since the runner's leg is there to prevent a fall.
[0060] FIG. 11c shows the option of front/back pack extension 690
for comfortable and optimal pack load support. The running/walking
brace shown is front/back brace leg 650 of FIG. 38. Front pack
frame 692 is pivotly attached to the top front of front/back brace
leg 650 by pack-frame pivot 698, and back pack frame 694 is pivotly
attached to the top back of front/back brace leg 650 by pack-frame
pivot 698. Pack straps 696 attach front pack 700 to front pack
frame 692, and back pack 702 to back pack frame 694. If the brace
legs were not supporting the pack weight, there would be an
uncomfortably high load on the runner's shoulders. Also, the front
parts of front/back pack extension 690 can be eliminated, in which
case runner 1 must lean forward at the waist to balance the pack.
Note that one option is for harness 683 to not couple to the pelvic
region of runner 701 in a supportive manner; in this case,
front/back brace leg 650 simply supports the packload. This
eliminates the difficult problem of coupling to the runner and
makes for an easier product.
[0061] FIG. 12 (12a a front view and 12b a side view) shows another
application of the p-diamond invention, namely p-diamond prosthesis
130. Pylon 120 would be attached at its top to a conventional
below-knee socket engaging the stump of an amputee. Pylon 120 is
rigidly attached to p-diamond sole 8 which is detailed in earlier
figures. Since there is no runner's foot in this application,
lengthwise springs 57 can be moved closer to the center. Also,
brace cross bar 682 can be made narrower on the top, at the level
of top length link 23, to allow a bow version of lengthwise spring
57 to bow upward without interference. FIG. 12c shows a front view
or another variation of p-diamond prosthesis 130. Here, p-diamond
linkage 9 is much taller (by virtue of diamond links 10 and end
links 14 being much longer). The side view would be equivalent to
FIG. 12b except for this tall feature. Now, in FIG. 12c, prosthetic
bow spring 124 can be oriented vertically, pushing directly and
vertically between brace cross bars 682 at the top and bottom of
p-diamond sole 8. Prosthetic bow spring 124 is pivotly connected to
brace cross bars 682 via bow spring pivots 126. Note, that
vertically stacked p-diamond 27 of FIG. 2c can alternatively be
used in the variation of FIG. 12c. Also, the p-diamond invention
could just as well be used at the thigh level of an above-knee
prostheses. Finally, the p-diamond can be used with active and
passive (using springs), or combinations of the two, to aid in
actuation of any limb or actuated element, such as arms, legs,
necks, torsos, etc.
[0062] Another application of the p-diamond invention is bow shoe
202 shown in FIG. 13 (a side view and FIG. 14 a front view). It
combines shin-level bow 240 and compressible p-diamond sole 8. All
details such as the various springs are not shown here, but any of
the features of the space shoe discussed earlier can be
incorporated into the bow shoe. FIG. 13a shows heel-strike, FIG.
13b shows mid-stance with p-diamond sole 8 compressed, and FIG. 13c
shows toe-off. Here, p-diamond sole 8 is equivalent to that shown
in FIG. 3. Ankle-pivot supports 226 are rigidly attached on either
side to lower frame 4--to support ankle-pivot housings 234 and
ankle pivots 232. Stirrups 236 are pivotly connected to ankle-pivot
support 226 by ankle pivot 232, and they prevent interference of
the bow support section with runner's shin 3. Bow 240 is pivotly
attached to stirrup 236 via lower bow hinge 242, and bow guide 238
is rigidly attached to stirrup 236. The top of bow 240 is pivotly
attached to bow guide 238.
[0063] Cords 228 attach to a front and a rear side point on upper
frame 6 at equal distances in front of and behind ankle-pivot
support 226. Cords 228 extend up to be guided through the center of
ankle-pivot housing 234 so as to minimize any torque exerted by
cord 228 on bow guide 238 about ankle pivot 232. Cords 228, four in
all--from the front and rear on both sides, extend further up to
attach to upper bow hinge 244. Accordingly, when runner's foot 1
pushes down on upper frame 6 during foot-strike, bow 240 is loaded
via cords 228. Since rear and front cords 228 are symmetrically
positioned about ankle-pivot support 228 and since p-diamond sole 8
forces vertical compression, bow 240 is loaded by either or both
heel and toe impact. This ensures that the full impact energy is
returned through the runner's toe at toe-off. To keep bow 240 from
flopping about, it is attached to shin strap 246 via shin slider
248 which is slidingly connected to the upper part of the
telescoping bow guide 238.
[0064] There are several embodiments of a "full energy return"
linkage other than the p-diamond linkage. These do not provide as
full a constraint on the relative motion of the top and bottom sole
plates as the p-diamond linkage, but they still have useful
functionality for full energy return in walking or running. Most
importantly, full energy return means that all heel and forefoot
impact energy (neglecting friction losses) is returned for thrust,
optimally in the latter part of toe-off. The signature feature of
these embodiments is that they extend over the full or major length
of the foot. Also, all of the features that apply to use of
p-diamond linkage 9, such as push-off frame 18, apply to these
other embodiments.
[0065] The next embodiment, shown in FIG. 15, is p-linkage 500.
FIG. 15a shows the four links that form a parallelogram (hence, th
"p"), namely top p-link 501, bottom p-link 502, and two vertical
p-links 503. Diagonal spring 505 stores the energy of impact and
compression, and forces the later expansion of p-linkage 500. Any
of these linkages can be oriented backwards or forwards, but if the
forward direction is to the left of FIG. 15, top p-link moves
backward with respect to bottom p-link 502 during impact. This has
the advantage of reducing the effective line of force angle of the
leg on the runner's center of mass, thereby reducing deceleration
in the heel-strike period. Also, the opposite relative motion
occurs in toe-off accelerating the runner forward more rapidly.
Later, variations in the p-diamond configuration will be shown to
achieve this same "slingshot` effect. It remains to be seen if this
longitudinal relative motion is too large, because it cannot be
precisely controlled as is the case for the next embodiments. FIG.
15b shows a line-link side view of p-linkage 500. This simplified
view will be used to illustrate the various alternative
configurations because the essence of their functionality is
thereby more easily seen. FIG. 15c shows arbitrary length 4-link
linkage 510, which recognizes that there may be good design reasons
for the lengths of a 4-link linkage may have the somewhat arbitrary
values of arbitrary length links 507. The main point of this patent
is that 4-link linkages permit control of the motion and
orientation of a runner's foot. Exact values or symmetries may not
be necessary or even recommended.
[0066] FIG. 16 shows a third linkage embodiment, 2-p linkage 511.
This utilizes diagonal springs 505, and other springs such as
vertical spring 19 could also be used. Here, the relative
longitudinal motion of the upper and lower links can be precisely
controlled (about zero), either with different forces for the upper
and lower diagonal springs 505, e.g., asymmetric diagonal spring
518, or by using asymmetric vertical p-link 516 (of different
length). Both of these control strategies are shown in FIG. 16b of
asymmetric 2-p linkage 518.
[0067] FIG. 17a shows one-spring tilting linkage 520 which uses
link-to-plate support 523 to minimize the maximum tilt of the top
sole plate. One-spring 524 stores impact energy via short links
521. FIG. 17b shows two-spring tilting linkage 530 which does not
require link-to-plate support 523. Upper and lower springs 534 and
535 store impact energy as two-spring short links 531 and
two-spring long links 532 rotate, pulling them against the ends of
two-spring 533. The linkage of FIG. 17 do not belong with or
compare favorably with the other linkages herein because the left
side of the sole does not compress any significant distance. These
are shown to emphasize inherent superiority of the parallelogram
based linkages of this invention.
[0068] FIGS. 18b (side view) and 18b (front view) show a variation
on p-diamond sole 8 wherein space shoe 2 rests in a recessed
structure, namely half-height plate 540 supported by half-height
hangars 542 from the tops of p-diamond linkage 9 on either side of
space shoe 2. This feature reduces the height of the runner's foot
above ground, as compared with the design of FIG. 18a, and this
feature can be used with of the linkage embodiment of this
invention. It does, however, restrict the use of a pre-bent bow 51
to only the lower half of the height of p-diamond linkage 9.
Normally, bows can be used in both halves.
[0069] FIG. 19 shows variations on the configuration of p-diamond
linkage 9, namely asymmetric p-diamond linkage 545. FIG. 19a shows
longer front diamond links 546, and FIG. 19b shows short link 521
and long link 522, which can be used to control the longitudinal
relative travel.
[0070] In summary, this invention includes several "full energy
return" linkages, all of which extend to full length of the shoe
and all of which constrain full sole length compression so that
springs can return full impact energy at toe-off. Note that the
orientation of any of the "full energy return" linkages of this
invention could be rotated ninety degrees about the vertical axis
so that the vertical links open laterally rather than
longitudinally, provided that the effective "width" of this linkage
be the full length of the shoe sole. For example, in FIG. 16a, the
orientation could be such that the direction into the paper for the
right foot is the forward direction. The vertical p-links 503 on
the right are now protruding toward the outside of the right foot,
and the "width" of the linkage must be the sole length to achieve
full energy return. In other words, the links would have to be that
sole-length wide or several linkages could be arrayed laterally
along the sole length and structurally connected to act as one. It
is unlikely that this orientation would be favorable, because the
spring length would be shorter, and that is probably a design
liability.
* * * * *
References