Note: Descriptions are shown in the official language in which they were submitted.
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Adaptable Spring Device For Walking And Running
This invention relates to a spring device for walking and running, which is
put on feet by
providing the user a spring action in movement on the ground. Those types of
the devices
have the elastic system that absorbs, stores and returns the kinetic energy to
the user of
the device during the gait cycle.
Background Of The Invention
It is well known that the center of mass commits vertical motions with each
step when
person runs or walks. And with each step a person throws up himself for a few
centimeters
by spending the energy and loses the most portion of that energy irrevocably.
The main purpose of the device, which has an elastic system, is the
conservation and
returning the energy to a user and the reduction of shock loads on the joints
of legs and
spine rights.
The effectiveness of such devices depends on the optimal condition of the
energy
exchange between a device and a person in locomotion. This optimal condition
exists
when the inert forces are balanced the elastic forces then exchange of energy
is maximally
free between a person and a device. This is known as a resonance. However, the
condition
of resonance depends on individual characteristics of each person. And if the
device works
best for one user it will be not work well for other. This is a serious
disadvantage of such
devices. Thus, the individual setting is necessary to each user, since the
elastic system is
the device plus the unique person with his characteristics.
The existing inventions do not take into account the condition of resonance.
Typical
devices of this kind are shown, for example, in the following United States of
America
patents:
75,900 Hale and Hubbell
871,864 Feazell and Thompson
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1,587,749 Bierly
4,360,978 Simpkins However
4,534,124 Schnell
5,343,636 Sabol.
But these devices are not adaptable for variety of users with different weight
and manner of
motion.
6,436,012 Naville.
In the device mentioned above the intermediate section comprises of separate
parts in
order to adjust the resistance of that intermediate section according to the
weight of a user.
But it is requires the availability of a few of parts for central section that
increases the cost
of the device. Besides, if these parts are metal springs, it increases the
weight of the
device. Moreover, the device is not adapted to a manner of locomotion of a
user. As a
result, the user must be adjusted to the device, but it should be conversely,
the device
must be adapted to the user.
Summary Of The Invention
To create comfortable resonant conditions for running or walking the device
must be
adapted to a specific user.
An object of present invention is the device that is adapted to variety of
users according to
its mass and to its unique manner of locomotion. This creates favorable
conditions for
energy exchange between the device and the individual to move with greater
ease and
comfort.
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Another object of this invention is to provide a method of adjustment of the
device.
Characteristics of a person that are taken into account are the mass of a
person (weight),
his style of movement and his pattern of locomotion. There are three style of
movement,
respectively, when a person put down his foot on a ground with rearfoot,
midfoot or forefoot
strike. In general, for walking a person uses the rearfoot style.
We know that running consists of two phases, namely, the phase of the support
and the
transport. When person is walking the transport phase disappears and we have
only phase
of support. The duration of the phase of support is very important because it
defines
condition of interaction of the device and a person.
The condition of resonance is performed when the time of the response of
elastic system
(device plus person) equals to the duration of the phase of support, where the
phase of
support is calculated under the comfortable conditions, namely, for
comfortable length of
step and favorable velocity for a person without a device.
Configuring the device is composed of coarse and accurate tuning. Coarse
tuning is the
choice of the laminate springs and the position of cam-bearing between them.
Coarse
tuning defines the period of natural oscillation. Accurate tuning is to adjust
flexible
constraints, which can be shortened or lengthened.
Order Of Adaption The Device To The Person
1. Define comfortable step's length of the person (right foot to left foot).
It is defined by
leg's length and angle between hips. Approximately it is equal to leg's
length.
2. Define favorable velocity of a motion of the person without any device.
3. Calculate comfortable foot-ground contact time. It is calculated based on
the ratio of
comfortable step's length to favorable velocity.
4. Calculate the resonant frequency of the device. The resonant frequency
equals to
the inverse of comfortable foot-ground contact time.
5. Calculate the comfortable stiffness of the device. The comfortable
stiffness equals to
mass of the person multiplied by the square of the resonant cyclic frequency.
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6. Calculate the static deflection under load of the weight of the person. It
is calculated
based on the ratio of the weight of the person to the comfortable stiffness.
7. Adjust of the device according to the static deflection by shifting cam-
bearing and by
shortening or lengthening the adjustable flexible constraints.
For example: my mass of body is m = 80 kg or my weight is 800 H
1. My comfortable step's length is 0.9 m
2. My favorable velocity of a motion is 3.2 m/s
3. Comfortable foot-ground contact time equals 0.9/3.2 = 0.281 s
4. Resonant frequency of the device is 1/0.281 = 3.56 1/s
5. Comfortable stiffness of the device is mXw2 = mx(21rf) 2= 80x(2x3.14x3.56)2
=
40000 H/m
6. Static deflection under load of the weight of the person is 800/40000 =
0.02 m =
2 cm
7. We choose the position of the cam-bearing such that the ends of upper and
lower
laminate springs have the static deflection, mention above (2 cm), under load
(rearfoot or forefoot) of the weight of the person. Then, we set the initial
value of the
elastic force by adjusting flexible constraints.
Brief Description Of The Drawings
1. Fig.1 is a side view of a schematic of the device.
2. Fig.2 is a side view of the device in the position of rearfoot loading
(device loaded by
the heel) when upper laminate spring is shifted forward relatively to the
lower
laminate spring.
3. Fig.3 is a side view of the device in the position of forefoot loading
(device loaded by
the tip of the foot) when upper laminate spring is shifted forward relatively
to the
lower laminate spring.
4. Fig.4 is a side view of the device in the position of rearfoot loading when
upper
laminate spring is shifted rearward relatively to the lower laminate spring.
5. Fig.5 is a side view of the device in the position of forefoot loading when
upper
laminate spring is shifted rearward relatively to the lower laminate spring.
6. Fig.6 is a transverse cross-sectional view of the supporting cam-bearing
and upper
laminate spring in two positions on larger scale: non-load and under load.
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Detailed Description Of The Invention
Fig.1 shows the construction of the embodiment of the adaptable spring device
for walking
and running according to the invention. Upper 1 and lower 2 laminate springs
are
approximate the outline of normal footwear. The ends of laminate springs 1 and
2 have the
adjustable flexible constraints 5. The cam-bearing 3 can be rearranged and
clamped in
different positions between laminate springs 1 and 2. By that the device
adapts to the style
of motion of the person (rearfoot, midfoot, forefoot strike).The joint 4
allows to the laminate
springs land 2 to be pivoting. And user can do comfort angle between upper and
lower
laminate springs 1 and 2. Through the joint 4 laminate springs I and 2 work
effectively by
accumulating energy over its entire length during forefoot load and rearfoot
load. Lower
laminate spring 2 is wider than the upper laminate spring 1 for lateral
stability. The device
attaches to the footwear by using securing straps Velcro 6. The material 7 is
suitable for
contact with terrain, which is affixed to the bottom of lower laminate spring
2. The laminate
springs 1 and 2 are fabricated from the suitable high tensile strength spring
material such
as composite material of carbon fiber or fiberglass. The adjustable, flexible
constraints 5
are aircraft cable or other. The cam-bearing 3 with joint 4 can be fabricated
from composite
materials or other.
In the phase of support the kinetic energy of the person's body is transformed
to the
potential energy of bending beams (laminate springs 1 and 2) and goes
inversely.
Additionally, there is a torque when the laminate springs 1 and 2 are shifted
relatively to
each other.
In Fig.2 and Fig.3 shown that couple of forces (the weight of the person W and
the ground
reaction force R) creates the torque T for the motion of the person that
pushes the person
forward (aggressive style of motion).
In Fig.4 and Fig.5 shown that couple of the forces (the weight of the person W
and the
ground reaction force R) creates the torque T against the motion of the person
(comfortable style). In this case the torque T presses the device to the foot
of the person
(feedback) and the person feels complete control over the device.
In Fig.6 shown that the cam-bearing 3 has a special profile where a point of
support 8
when the device is non-loaded and a point of support 9 when the device is
under loaded by
heel. The shift of the point of support by bending laminate springs 1 and 2
increases
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stiffness of the device. When the person puts down his foot on the ground, the
stiffness of
the device is minimal, and when the deflection of laminate springs 1 and 2 is
maximal, the
stiffness is maximal too. Thus, the work of the device becomes more
comfortable for the
user.
The device can be used as a simulator for rehabilitation after injury.
The method of calculation can be used in the design of such devices with an
elastic
system.
