U.S. patent application number 12/578018 was filed with the patent office on 2010-02-04 for energy returning prosthetic joint.
Invention is credited to Vilhjalmur Freyr Jonsson, Christophe Guy Lecomte, Magnus ODDSSON.
Application Number | 20100030342 12/578018 |
Document ID | / |
Family ID | 37637830 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100030342 |
Kind Code |
A1 |
ODDSSON; Magnus ; et
al. |
February 4, 2010 |
ENERGY RETURNING PROSTHETIC JOINT
Abstract
An energy returning prosthetic joint arranged for use as a knee
joint in prosthetic limbs includes a biasing or spring member
connected to upper and lower attachment members. The spring member
includes a composite material having an energy returning property.
A cushion may be provided within the range of curvature of the
spring member, or be connected to frame members in order to limit
motion of the spring member.
Inventors: |
ODDSSON; Magnus;
(Hafnarfjordur, IS) ; Jonsson; Vilhjalmur Freyr;
(Reykjavik, IS) ; Lecomte; Christophe Guy;
(Reykjavik, IS) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE, FOURTH FLOOR
ALEXANDRIA
VA
22314-1176
US
|
Family ID: |
37637830 |
Appl. No.: |
12/578018 |
Filed: |
October 13, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11483676 |
Jul 11, 2006 |
7618463 |
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12578018 |
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60697552 |
Jul 11, 2005 |
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60794823 |
Apr 26, 2006 |
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Current U.S.
Class: |
623/27 ;
623/44 |
Current CPC
Class: |
A61F 2002/30359
20130101; A61F 2/76 20130101; A61F 2220/0041 20130101; A61F
2002/5007 20130101; A61F 2002/5039 20130101; A61F 2/60 20130101;
A61F 2002/5043 20130101; A61F 2002/30433 20130101; A61F 2002/608
20130101; A61F 2002/503 20130101; A61F 2002/5033 20130101; A61F
2/68 20130101; A61F 2220/0033 20130101; A61F 2002/5079 20130101;
A61F 2/64 20130101 |
Class at
Publication: |
623/27 ;
623/44 |
International
Class: |
A61F 2/74 20060101
A61F002/74; A61F 2/64 20060101 A61F002/64 |
Claims
1. An energy returning prosthetic joint, comprising: a spring
member formed of a material having an energy returning property,
the spring member defining at least one asymmetrical curvilinear
portion defining an open space, the spring having top and bottom
sections extending from opposed ends of the at least one
curvilinear portion.
2. The prosthetic joint according to claim 1, wherein the bottom
section generally extends linearly, the top section oriented
obliquely relative to the bottom section.
3. The prosthetic joint according to claim 2, further comprising
first and second attachment members connected to the top and bottom
sections of the spring member, the first and second attachment
members oriented generally along the same axis.
4. The prosthetic joint according to claim 1, further comprising a
limiting member coupled to said spring member within said open
space.
5. The prosthetic joint according to claim 1, wherein: the at least
one curvilinear portion includes an upper asymmetric curvilinear
portion, and a lower asymmetric curvilinear portion, the upper and
lower curvilinear portions each defining a convex open space, the
upper and lower curvilinear portions being connected to one another
at corresponding ends thereof, and oriented in opposite directions
relative to one another.
6. An energy returning prosthetic joint, comprising: a lower frame
member having a lower portion and an upper portion; an upper mount
member pivotally connected to the upper portion of the lower frame
member; and a biasing member having an upper end and a lower end,
the lower end of the biasing member connected to the lower portion
of the lower frame member and the upper end of the biasing member
connected to the upper mount member; and a damper disposed between
the upper mount and the lower frame members such that the biasing
member urges the upper mount and lower frame member towards one
another with the damper therebetween in a stance phase.
7. An energy returning prosthetic joint, comprising: a lower frame
member having a lower portion and an upper portion; an upper mount
member pivotally connected to the upper portion of the lower frame
member; and a biasing member having an upper end and a lower end,
the lower end of the biasing member connected to the lower portion
of the lower frame member and the upper end of the biasing member
connected to the upper mount member; wherein during a stance phase,
the biasing member is arranged to provide stance flexion and,
during a swing phase, the biasing member is arranged to provide
energy return; wherein the lower frame member further comprises a
cushion located near the upper portion of the lower frame member
and also located anterior to the pivotal connection between the
upper mount and the lower frame member, such that, when the
prosthetic joint is in a stance phase, the upper mount is arranged
to rest upon the cushion.
Description
[0001] This application is a divisional application from U.S.
application Ser. No. 11/483,676, filed on Jul. 11, 2006, which
claims the benefit of U.S. provisional application No. 60/697,552,
filed on 11 Jul. 2005, and U.S. provisional application No.
60/794,823, filed on 26 Apr. 2006.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
prosthetic limbs, and more particularly to a prosthetic joint.
BACKGROUND
[0003] Artificial limbs, including leg prostheses, employ a wide
range of technologies to provide solutions suitable to many
differing needs. For a trans-femoral amputee, basic needs in a leg
prosthesis include stability, while standing and during the stance
phase of a walking gait, and mechanical compatibility with the
walking (or running) gait and some manner of knee flexion during
stance and swing phases of a gait.
[0004] Certain trade-offs exist between stability, and walking or
running performance. A simple, non-articulable leg (having no
movable knee), for example, may provide maximum stability, but does
not provide for an ideal gait. Also, sitting may be awkward if a
person cannot bend their knee.
[0005] For people having lost their biological knees, it is
important that the prosthetic joint functions properly and is
reliable. There are numerous types of prosthetic joint designs
available, each having its benefits and shortcomings.
[0006] A widely used prosthetic joint design is of a single axis
type. The single axis knee employs a simple hinge at the level of
the anatomical knee. Such a simple design results in low cost,
light weight, and durability. However, little gait assistance is
provided to the amputee by the limb itself; the amputee is required
to expend a certain degree of muscle power to help to control and
stabilize the prosthetic leg.
[0007] The single axis knee may be configured with a fluid control
unit to increase or decrease the swing phase resistance as one
speeds up and slows down. Yet by adding the fluid control unit, the
cost of the knee and complexity of the knee are greatly
increased.
[0008] In accordance with another type of prosthetic joint, a
polycentric knee design employs a mechanically complex plurality of
hinge or rotation points that allow variations in the action of the
knee through the gait, typically providing increased stability
early in the stance phase while allowing easy bending during the
swing phase and while sitting. Additional mechanical complexity is
often found in the form of air or hydraulic cylinders that vary
swing phase resistance or flexion during variations in the gait, or
provide for shock absorption. Microprocessor controllers may be
employed to measure aspects of the gait to control operation of the
air or hydraulic cylinders or other components of the knee.
[0009] Of course, because of the complexity of the polycentric knee
design, this design is not as reliable as the single hinge design.
Moreover, this design costs substantially more to produce than the
single hinge design due to its additional moving parts.
[0010] Other highly complex mechanical (and in some cases
microprocessor controlled) prosthetic joints have evolved to
improve the performance of leg prostheses. Current prosthetic
joints are often a complicated system including joints, arms,
bearings, cylinders, and other mechanical and electromechanical
components. Further, some employ sophisticated electronics
including microprocessor circuits and instrumentation of the
various parts of the knee.
[0011] The complexity of such prosthetic joints tends to adversely
affect the potential life of the knee as well as security to the
user, as the parts are subject to wear. Moreover, with increased
mechanical and electronic complexity comes the need for increased
maintenance and tuning to achieve or maintain proper function.
[0012] It is therefore desirable to provide a prosthetic joint that
provides improved functionality, user security, and performance in
a simplified structure having few moving parts, and that can be
produced at low cost.
SUMMARY
[0013] In order to overcome the shortcomings of known prosthetic
joints, different embodiments are provided which pertain to an
inventive joint that can be used in a prosthetic leg.
[0014] In one embodiment, a prosthetic joint is constructed from a
material having an energy returning property. The knee has a base
portion configured in a substantially planar shape, an arcuate
portion having a first end connected to the base portion, and an
asymmetrical curvilinear portion connected to a second end of the
arcuate portion and extending obliquely relative to the base
portion. A first attachment member is securable onto the base
portion and a second attachment member is securable onto the
curvilinear portion. Each of the attachment members includes a
locking feature provided for coupling the upper and lower portions
of the prosthetic leg. The locking features of the first and second
attachment members are axially aligned with one another.
[0015] In another embodiment, the knee is a spring member formed
from a material having an energy returning property. The knee
defines an upper curved portion connected to a lower curved
portion. An upper base portion is provided that extends from the
upper curved portion preferably in a substantially planar
configuration. A lower base portion is provided that extends from
the lower curved portion preferably in a substantially planar
configuration.
[0016] The upper and lower curved portions are preferably
asymmetrical, and are connected to one another so that they are
inverted or oriented relative to one another in opposite
directions. For example, the upper curved portion projects towards
an anterior side and the lower curved portion projects toward a
posterior side. Of course, the upper and lower curved portions may
be reversed in orientation such that the upper curved portion
projects towards the posterior side, and the lower curved portion
projects towards the anterior side.
[0017] The upper curved portion tends to provide vertical shock
relief as well as protection against over extension of the knee.
The lower curved portion tends to provide for flexion of the knee
during stance and swing phases of a gait.
[0018] The lower curved portion defines a convex open space,
wherein a damping or limiting member may be placed to damp or limit
the rapid extension of the knee that results from the energy
returning nature of the material of the spring member.
[0019] According to a variation of the embodiment, the knee is a
spring member having only a single asymmetrically curved portion.
An upper base portion is provided that extends from one end of the
posterior curved portion preferably in a substantially planar
configuration. A lower base portion is provided that extends from
another end of the posterior curved portion preferably in a
substantially planar configuration. The upper and lower base
portions are spaced apart from one another and are preferably
arranged generally parallel to relative to one another.
[0020] The orientation of the asymmetrically curved portion may be
positioned to project in either of the anterior or posterior
directions.
[0021] In another embodiment, the prosthetic joint includes an
upper mount member, a lower frame member, and a spring or biasing
member. The upper mount member is pivotally connected to an upper
portion of the lower frame member. The biasing member has an upper
end and a lower end, with the lower end connected to the lower
portion of the lower frame member and the upper end connected to
the upper mount member. These connections may be of any suitable
type that allows compression of the biasing member, with pivotal
connections being preferred so that the internal stresses of the
biasing member near the connections do not become too large and so
that the biasing member does not transfer a rotational moment, in
the axis of the joint rotation, to the upper mount member or the
lower frame member.
[0022] The pivotal connection between the upper end of the biasing
member and the upper mount may be located posterior to the pivotal
connection between the upper mount and the lower frame member.
[0023] The prosthetic joint is constructed so that during a stance
phase, the biasing member provides stance flexion and, during a
swing phase, the biasing member provides energy return.
[0024] In another embodiment of the prosthetic joint, a damper is
disposed between the biasing member and the lower frame member. The
damper may have a first passageway and the lower frame member may
have a second passageway such that the first passageway
communicates with the second passageway. Additionally, the damper
may have a first end and a second end, with the second end
connected to an interior surface of the lower frame member. The
biasing member may have a posterior surface that contacts the first
end of the damper during a swing phase of the prosthetic joint so
that the first and second passageways act to slow energy return
provided by the biasing member during the swing phase.
[0025] In yet another embodiment, the shape and size of the first
and second passageways can be varied in order to adjust the energy
return of the biasing member during the swing phase.
[0026] Another feature is that the first end of the damper can be
adjusted to be closer to and further from the posterior surface of
the biasing member in order to adjust the energy return of the
biasing member during the swing phase.
[0027] Another feature comprises stiffness adjusting mechanisms
located around an outer surface of the damper such that the
stiffness of the damper may be adjusted in order to adjust the
energy return of the biasing member during the swing phase.
[0028] In another embodiment, the prosthetic joint is configured to
brake over a pivot point during a sitting phase.
[0029] According to this embodiment, a cushion is located near the
upper portion of the lower frame member, anterior to the connection
between the upper mount member and the lower frame member, such
that, when the prosthetic joint is in a stance phase, the upper
mount rests upon the cushion and the cushion provides stance
flexion.
[0030] In yet another embodiment, along with the above described
first damper, a second damper may be disposed between the biasing
member and the lower frame member in order to provide resistance
against the flexion of the biasing member during the toe-off phase.
The second damper can be provided with stiffness adjusting
mechanisms in order to adjust the amount of resistance provided
against the flexion of the biasing member during the toe-off phase.
The second end of the second damper can be adjusted to be closer to
and further from the anterior surface of the biasing member in
order to adjust the amount of resistance provided against the
flexion of the biasing member during the toe-off phase.
[0031] Additionally, in other embodiments, the amount and rate of
energy return during the swing phase can be varied.
[0032] The advantages of the improved energy returning prosthetic
joint disclosed herein include a simpler mechanical design that is
not as susceptible to failure as a more complex, polycentric
design, while at the same time providing a good balance between the
need for stability in the stance phase, while allowing for stance
flexion, providing resistance to flexion during the toe-off phase
and further providing energy return assistance during the swing
phase.
[0033] These, and other advantages of the improved energy returning
prosthetic joint, will become better understood in light of the
following description, appended claims, and accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a side elevational view of one embodiment of an
energy returning prosthetic joint.
[0035] FIG. 2 is a perspective view of the prosthetic joint
according to FIG. 1.
[0036] FIG. 3 is a side elevational view of another embodiment of
an energy returning prosthetic joint.
[0037] FIG. 4 is a side elevational view of yet another embodiment
of an energy returning prosthetic joint.
[0038] FIG. 5 is a side elevational view of a prosthetic assembly
incorporating a prosthetic joint.
[0039] FIG. 6 is a side elevational view of another embodiment of
an energy returning prosthetic joint, shown in a full extension
position.
[0040] FIG. 7 is a side elevational view of the energy returning
prosthetic joint in FIG. 6, shown in a maximal flexion
position.
[0041] FIG. 8 is a side elevational view of a second embodiment of
an energy returning prosthetic joint, shown in a full extension
position.
[0042] FIG. 9 is a side elevational view of the energy returning
prosthetic joint in FIG. 8, shown in a maximal flexion
position.
[0043] FIG. 10 is a side elevational view of a third embodiment of
an energy returning prosthetic joint, shown in a full extension
position.
[0044] FIG. 11 is a side elevational view of the energy returning
prosthetic joint in FIG. 10, shown in an intermediate flexion
position.
[0045] FIG. 12 is a side elevational view of the energy returning
prosthetic joint in FIG. 10, shown in a maximal flexion
position.
DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS
A. Environment and Context of the Various Embodiments
[0046] In order to understand the operation of the energy returning
prosthetic joint described herein, a basic discussion of the gait
cycle is required. A gait cycle defines the movement of the leg
between successive heel contacts of the same foot. The gait cycle
has two phases: stance and swing. The stance phase has three time
periods: heel-strike, mid-stance and toe-off.
[0047] At some point during mid-stance, the knee joint will be at
full extension. An actual knee joint will have some flexion between
heel-strike and mid-stance and between mid-stance and toe-off. This
is called "stance flexion." Not all prosthetic joints provide for
stance flexion, and for those that do, they are either mechanically
complex, expensive, or both. Moreover, these prosthetic joints
typically require frequent maintenance and replacement.
Additionally, the amount of stance flexion required can vary from
user to user, while most prosthetic joints have no
adjustability.
[0048] Maximum flexion of the knee joint, while walking, will occur
at the end of the toe-off phase. The amount of maximum flexion is
typically determined in part by the speed at which a person is
walking. The faster a person walks, the greater the amount of
maximum flexion, while the slower a person walks, the lesser the
amount of maximum flexion. In a natural knee, the amount of maximum
flexion can be controlled and limited via the musculature of the
leg. In a prosthetic knee joint, some artificial means of
controlling and limiting the amount of maximum flexion must be
provided. Immediately following the end of the toe-off phase begins
the swing phase.
[0049] While the stance phase has three time periods, the swing
phase has two time periods: acceleration and deceleration. The
acceleration phase begins immediately following the maximum flexion
during the toe-off phase. During the acceleration phase, the lower
portion of the leg, consisting of the shin and foot, begins to
swing back towards full extension. In a natural knee joint, a
deceleration phase follows the acceleration phase, during which the
lower portion of the leg continues to swing towards full extension.
Some prosthetic joints do not provide for any deceleration during
the swing phase. Other prosthetic joints provide deceleration by
using costly and bulky hydraulic or pneumatic cylinders. The amount
of deceleration required can vary from user to user, while most
prosthetic joints have no adjustability.
[0050] In one embodiment of the invention, the energy returning
prosthetic joint described herein provides both stance flexion
during the stance phase, and deceleration during the swing phase.
In another embodiment of the invention, the energy returning
prosthetic joint described herein also provides a limitation on the
maximum amount of flexion during the toe-off phase. The embodiments
described herein accomplish these features with a mechanically
simple construction, without complex linkages subject to frequent
maintenance and replacement.
[0051] For further ease of understanding the joint disclosed
herein, a description of a few terms is necessary. As used herein,
the term "upper" has its ordinary meaning and refers to a location
that is above, or higher than another location. Likewise, the term
"lower" has its ordinary meaning and refers to a location that is
below, or underneath another location. The term "posterior" also
has its ordinary meaning and refers to a location that is behind or
to the rear of another location. Lastly, the term "anterior" has
its ordinary meaning and refers to a location that is ahead or to
the front of another location.
B. First Embodiment
[0052] A first embodiment of an energy returning prosthetic joint
is illustrated in FIGS. 1 and 2. In accordance with this
embodiment, a prosthetic joint 10 is constructed from a material
having an energy returning property. The knee has a base portion 12
configured in a substantially planar shape, and has first and
second ends 28, 30. An arcuate portion 14 having a first end 32 is
connected to the second end 30 of the base portion. A first end
portion 36 of an asymmetrical curvilinear portion 16 is connected
to a second end 34 of the arcuate portion 14. Preferably, the
curvilinear portion 16 extends from the arcuate portion 14
obliquely over and relative to the base portion 12.
[0053] The curvilinear portion 16 has a variable radius such that
its curvature varies over its length. For example, according to the
embodiment shown in FIG. 1, the curvature of the curvilinear
portion 16 preferably has a greater curvature near its first end
portion 36. The curvature greatly decreases to nearly or at a
straight portion 22 near a second end portion 38 of the curvilinear
portion 16.
[0054] In order to couple upper and lower leg prostheses, the
prosthetic joint 10 is provided with first and second attachment
members 18, 20 that are secured to portions of the prosthetic
joint. Preferably, the first attachment member 18 is secured onto
the base portion 12 and the second attachment member 20 is secured
onto the curvilinear portion 16. The attachment members 18, 20 are
secured onto a first side 24 of the prosthetic joint and are
preferably secured to the prosthetic joint 10 with fasteners 44
that extend into the attachment members 18, 20 from a second side
26 of the prosthetic joint 10.
[0055] Each of the attachment members includes a locking feature
40, 42 that is provided for coupling the upper and lower portions
of the prosthetic leg. The locking features 40, 42 of the
attachment members 18, 20 are axially aligned with one another
along axis A-A in a static configuration so as to provide stability
and balance of the knee.
[0056] Since the curvilinear portion 16 extends obliquely relative
to the base portion 12, the second attachment member 20 is shaped
differently from the first attachment member 18 such that the
second attachment member 20 is flush with the straight portion 22
while maintaining alignment of the locking feature 42 with the
locking feature 40 of the first attachment member.
[0057] Despite the arcuate portion 14 being shown in FIG. 1 as
having a generally uniform radius, it will be understood that the
arcuate portion 14 may have a variable radius, thereby defining a
non-uniform shape. While shown as being asymmetric, the curvilinear
portion 16 may be constructed so that it is symmetric or
substantially symmetric according to the desired energy returning
properties of the prosthetic joint and the patient.
[0058] The orientation of the asymmetrical curvilinear portion may
be positioned to project in either of the anterior or posterior
directions.
C. Second Embodiment
[0059] In accordance with another embodiment of the prosthetic
joint, FIG. 3 illustrates an energy returning prosthetic joint 100
comprising a generally "S" shaped spring member vertically oriented
between the upper, portion, or socket, of a leg prosthesis and the
lower portion, or pylori, of the leg prosthesis. An example of
upper and lower portions of a leg prosthesis system is described in
U.S. Pat. No. 6,589,289 incorporated herein by reference.
[0060] In accordance with the illustration shown in FIG. 3, the
anterior side of the knee is represented by I and the posterior
side of the knee is represented by II. The axis B-B demarcates the
boundary between the anterior and posterior sides of the knee
100.
[0061] The general "S" curve of the knee 100 defines an upper,
anterior curved portion 102, joined to a lower, posterior curved
portion 104. The anterior curved portion 102 terminates, at the top
of the knee 100, with an upper arm 108 that is adapted for
attachment to the upper portion of a leg prosthesis or to an
attachment member 122 having a locking feature 124 for attachment
to the upper portion of a leg prosthesis. Similarly, the posterior
curved portion 104 terminates, at the bottom of the knee 100, with
a lower arm 106 that is adapted for attachment to the lower portion
of a leg prosthesis or to an attachment member 118 having a locking
feature 120 for attachment to the lower portion of a leg
prosthesis.
[0062] Preferably, the upper and lower arms 108, 106 are generally
planar so that the attachment members 118, 122 are mounted flush
with the upper and lower arms 108, 106. While not shown, the
attachment members 118, 122 may be mounted to the knee 100 with any
known and suitable fasteners, for example the fasteners 44 shown in
the embodiment of FIG. 1. As with the embodiment of FIG. 1, the
locking features 120, 124 corresponding to the attachment members
118, 124 are preferably aligned along a common axis, axis B-B.
[0063] The anterior curved portion 102 defines a convex anterior
open space 110, while the posterior curved portion 104 defines a
convex anterior open space 126. The knee 100 is formed of an energy
returning material such as certain plastics or certain composite
materials including carbon or aramid fibers. The energy returning
material may also be reinforced with memory shape alloys, or other
suitable metal components.
[0064] The anterior curved portion 102 may be made relatively stiff
in comparison with the remainder of the knee 100, such as by
varying the thickness, width, or material composition in the region
of the anterior curved portion 102. Increased stiffness of the
anterior curved portion 102 assists to restrict the knee 100 from
over-extension, while the anterior curved portion 102 is still
allowed some flexion to provide for vertical shock relief as the
anterior curved portion 102 compresses somewhat under weight during
the stance portion of the gait.
[0065] The posterior curved portion 104 allows for flexion, by
opening of the posterior curved portion 104 during knee flexion
periods of the gait stance and swing. A damping or limiting member
116 may be disposed within the convex anterior open space 112 of
the knee 100 in order to control or limit the rapid extension of
the knee 100 resulting from the energy returning nature of the
material of the knee 100. The damping or limiting member 116 may
be, for example, a polymer rod or post that prevents excessive
closure of the posterior curved portion 104 that might result from
rapid or over extension of the knee 100.
[0066] In certain embodiments, the damping or limiting member 116
may be pre-tensioned to enhance performance in a preferred
direction. The damping or limiting member 116 performs a limiting
function if it is made of a rigid material, while if the damping or
limiting member 116 is made of a deformable resilient material it
performs a damping function as the material compresses, as well as
a limiting function once the material reaches a deformable
limit.
[0067] Turning now to FIG. 4, a variation of the embodiment of FIG.
3 is illustrated wherein an energy returning prosthetic joint 200
comprises a generally "C" shaped spring member disposed between the
upper portion of a leg prosthesis and the lower portion of the leg
prosthesis.
[0068] The "C" shape of the knee 200 defines a single
asymmetrically curved portion 202, which defines a convex open
space 208. The curved portion 202 terminates at the top of the knee
200 with an upper arm 206 that is adapted for attachment to the
upper portion of a leg prosthesis or to an attachment member 214
having a locking feature 216 for attachment to the upper portion of
a leg prosthesis. Similarly, the curved portion 202 terminates, at
the bottom of the knee 200, with a lower arm 204 that is adapted
for attachment to the lower portion of a leg prosthesis or to an
attachment member 210 having a locking feature 212 for attachment
to the lower portion of a leg prosthesis.
[0069] The knee 200 allows for flexion, by opening of the curved
portion 202 during knee flexion periods of the gait stance. As
described in the previous embodiment, a damping or limiting member
218 may be disposed within the convex anterior open space 208 to
control or limit the rapid extension of the knee 200 resulting from
the energy returning nature of the material thereof.
[0070] Referring to FIG. 5, an exemplary energy returning
prosthetic joint 100 is shown coupling an upper portion 126 of a
leg prostheses, the upper portion 126 comprising a hard socket, to
a lower portion 128 of the leg prostheses, the lower portion 128
comprising a pylori and a foot.
[0071] Because gait is asymmetrical with regards to flexion and
extension, the spring cannot be perfectly shaped in the S and C
shapes described in some of the embodiments. As a result, the
energy returning knee must be tuned to accommodate response of the
knee and preferably is asymmetrical. Such tuning may include
providing different radii to portions of the spring member, using
different material thicknesses, and inserting different types of
fibers into a laminate used to construct the knee.
[0072] Numerous materials and composites may be employed to
construct the energy returning knee according to the invention.
Some of the materials that may be used include carbon fiber, glass
fiber, titanium, stainless steel, resins, and epoxies. Memory
alloys may also be considered. Of particular note, if a laminate is
used to construct the knee, such as carbon fiber, different types
of fibers and layers may be incorporated, such as glass or titanium
fibers, at critical points in the curvature of the spring
member.
[0073] It will be understood that the prosthetic joint of the
second embodiment in FIG. 3 may be reversed in orientation, such
that "I" may denote the posterior side, and "II" may denote the
anterior side. Also, the variation of FIG. 4 may be similarly
reversed so that the curved portion projects either toward the
anterior or posterior sides.
D. Third Embodiment
[0074] Another embodiment of an energy returning prosthetic joint
is illustrated in FIGS. 6 and 7. In accordance with this
embodiment, the joint 310 has a lower frame member 320 constructed
from an appropriate material such as those capable of providing
lightweight structural support. Examples of such materials include,
but are not limited to, plastics, steel alloys, aluminum alloys,
other metals, ceramics, or other rigid materials. The lower frame
member has a posterior surface 390, an interior surface 392, and an
anterior surface 380. The lower frame member also has a lower
portion 322, an upper portion 324, and a middle portion 326.
[0075] An upper mount member 330 is connected to the upper portion
324 of the lower frame member 320. The upper mount member 330 is
constructed of any suitable material such as those capable of
providing lightweight structural support. Examples of such
materials include, but are not limited to, plastics, steel alloys,
aluminum alloys, other metals, ceramics, or other rigid materials.
The connection between the upper mount member 330 and the upper
portion 324 of the lower frame member 320 is a first pivot
connection 332.
[0076] The joint 310 is mounted to a prosthetic member in any
conventional manner, such as by providing four threaded holes in
the lower frame member 320 and the upper mount member 330 that will
fit any standard prosthetic component. The prosthetic components
allow the joint 310 to be attached to upper and lower prosthetic
members (not illustrated).
[0077] Connected to the upper mount member 330 and the lower frame
member 320 is a spring or biasing member 340. The biasing member
340 can be made from any suitable lightweight material that can
provide the appropriate biasing forces, such as metals and
synthetic or composite materials. The materials selected for the
biasing member 340 should allow for bending of the biasing member
340 without permanent deformation of the biasing member 340.
[0078] Another factor in determining the appropriate material to be
used for the biasing member 340 is that the modulus of the material
should be selected to match the weight of the user and the desired
range of motion of the joint 310. Examples of appropriate materials
include, but are not limited to, spring steels, carbon or glass
fibers in resins, or specially treated plastics. To further control
the spring response, a polymer dampening material may be adhered to
the biasing member 340. According to one variation, the biasing
member 340 is a carbon fiber spring or member.
[0079] The biasing member 340 has an upper end 342, a lower end
344, a middle portion 346, a posterior surface 348 and an anterior
surface 349, and can be constructed as a leaf spring, or any other
suitable shape that provides the appropriate biasing forces. The
biasing member 340 could be, for example, formed in an "S" shape in
order to yield different response curves. The bending of an "S"
shaped biasing member 340 would require much less horizontal
displacement than, for example, a "C" shaped biasing member 340 for
the same amount of vertical displacement. The illustrated biasing
member 340 is formed as a leaf type spring and should be pre-bent
to control which direction the biasing member 340 will bend.
[0080] The upper end 342 of the biasing member 340 is connected to
the upper mount member 330 at a second pivot connection 334. The
second pivot connection 334 is located posterior to the first pivot
connection 332. The lower end 344 of the biasing member 340 is
connected to the lower frame member 320 at a third pivot connection
328. The pivot connection can be constructed in any appropriate
manner including, but not limited to, laminating the eye, bending
the biasing member 340 around the eye, clamping the biasing member
340 to the eye, or providing a rubber bushing vulcanized to the end
of the biasing member 340.
[0081] Further, the second pivot connection 334 could be replaced
with any appropriate connection including, but not limited to,
providing a spiral end at the upper end 342 of the biasing member
340. Additionally, the third pivot connection 328 can be replaced
with any appropriate connection including, but not limited to, a
rigid connection.
[0082] The energy returning prosthetic joint 310 also includes a
damper 350 connected to the lower frame member 320 in any suitable
fashion, such as by bonding or mechanical fastening. The damper 350
can be made of any suitable material that can absorb energy, for
example rubber, plastic or a synthetic material such as a polymer.
The damper 350 has a first end 352, a second end 354 and an outer
surface 356. The second end 354 of the damper 350 is connected to
the interior surface 392 at the middle portion 326 of the lower
frame member 320 in any conventional manner.
[0083] The damper 350 further includes a first opening 362 in the
first end 352, a second opening 64 in the second end 354 and a
first passageway 360 that extends through the damper 350 from the
first opening 362 to the second opening 364. The sizes and shapes
of the first opening 362, second opening 364 and first passageway
360 can be adjusted to change the volume of the damper 350, and
hence the stiffness of the damper 350. The sizes and shapes of the
first opening 362, second opening 364 and first passageway 360 can
also be adjusted to limit the amount of airflow through the
openings and the passageway, as will be described in further detail
below.
[0084] The damper 350 also includes stiffness adjusting mechanisms
358 located along the outer surface 356 of the damper 350. The
stiffness adjusting mechanisms 358 can consist of any structure
that changes the volume and/or the geometry of the damper 350, such
as grooves having any desired shape, notches and tapers.
[0085] The lower frame member 320 additionally includes a second
passageway 370, located in the middle portion 326 of the lower
frame member 320. The second passageway 370 extends between the
posterior surface 390 of the lower frame member 320 and the
interior surface 392 of the lower frame member 320, and is in
communication with the second opening 364 in the damper 350. This
communication allows the passage of air from the first end 352 of
the damper 350, through the first opening 362, through first
passageway 360, through the second opening 364, through the second
passageway 370 to the environment past the posterior surface 390 of
the lower frame member. The size and shape of the second passageway
370 can be varied in order to adjust the amount of airflow
therethrough. The two passageways 360, 370, and the first and
second openings 362, 364 form an air vent that can be used to
adjust the energy return of the biasing member 340, as will be
further discussed below.
[0086] In this particular embodiment the anterior surface 380 of
the lower frame member 320 includes a clearance opening 382 that
allows the biasing member 340, while in a flexed position, to
extend through the anterior surface 380 of the lower frame member
320, as can be seen in FIG. 7.
[0087] In another variation, not shown, the anterior surface 380 of
the lower frame member 320 may not have the clearance opening 382,
but may be located such that when the biasing member 340 is in a
maximally flexed state, the anterior surface 349 of the biasing
member 340 does not contact the lower frame member 320.
[0088] In operation, the joint 310 may be used as a knee joint. The
joint 310 is shown in full extension in FIG. 6, with the biasing
member 340 minimally flexed and the damper 350 compressed. The
biasing member 340 provides the user with stance flexion during the
stance phase via the flexion of the biasing member 340.
Additionally, the posterior surface 348 of the biasing member 340
forms an air tight seal with the first end 352 of the damper 350.
During the end of the mid-stance phase and the beginning of the
toe-off phase, the biasing member 340 will flex and the damper 350
will expand.
[0089] The rate of this flexion and expansion is governed by the
fact that air is sucked through the second passageway 370, through
the second opening 364 and into the first passageway 360. The sizes
of the second passageway 370, through the second opening 364 and
into the first passageway 360 can all be varied to adjust the rate
of release of the biasing member 340 from the damper 350.
Additionally the location of the first end 352 of the damper 350
can be varied in relation to the posterior surface 348 of the
biasing member 340 in order to allow for another adjusting
parameter for the rate of release.
[0090] The joint 310 is shown in maximum flexion in FIG. 7. This
position may occur while a user is seated, and is used in an
exemplary way to show that during the maximal flexion of the joint
310 during the toe-off phase, the biasing member 340 no longer
forms an airtight seal with the first end 352 of the damper 350.
During the acceleration period of the swing phase, the biasing
member 340 provides energy return to the lower frame member 320. At
a point prior to full extension, the posterior surface 348 of the
biasing member 340 will contact the first end 352 of the damper
350.
[0091] Both the stiffness of the damping member 350 and the forcing
of air through the passageways 360, 370 and the second opening 364
provide the damping which slows the energy return of the biasing
member 340. As discussed previously, the stiffness adjusting
mechanisms 358, the sizes and shapes of the openings 362, 364 and
passageways 360, 370, and the location of the first end 352 of the
damper 350, can all be varied in order to adjust the energy return
of the biasing member 340, in order to provide appropriate
deceleration during the swing phase. This allows the joint 310 to
be adjustable to different user's gait dynamics.
E. Fourth Embodiment
[0092] A second embodiment of a energy returning prosthetic joint
is illustrated in FIGS. 8 and 9. In accordance with this
embodiment, the joint 410 has a lower frame member 420 constructed
from an appropriate material such as one capable of providing
lightweight structural support, such as the materials discussed
above in section D. The lower frame member has a lower portion 422,
an upper portion 424, and a mounting surface 426 for a damper or
cushion 470. The lower frame member can be formed integrally with a
U-shape defined by two flange portions that extend from a base
towards an upper mount member 430. Alternatively, the lower frame
member 420 can be formed from components, including a lower mount
member 450, and assembled in a conventional way, such as by bonding
or with mechanical fasteners. The preferred design would provide a
yoke that allows the upper mount member 430 to rotate at least 90
degrees.
[0093] In a one embodiment, the mounting surface 426 would bridge
the yoke portion of the lower frame member 420 in order to provide
more rigidity to the joint 410.
[0094] The upper mount member 430 is connected to the upper portion
424 of the lower frame member 420. The upper mount member 430 is
constructed of any suitable material such as those capable of
providing lightweight structural support, such as the materials
discussed above in section D. The connection between the upper
mount member 430 and the upper portion 424 of the lower frame
member 420 is a first pivot connection 432 that allows the upper
mount member 430 to rotate at least 90 degrees. The upper mount
member 430 also has a lower surface 436. The cushion 470 is
positioned anterior to the first pivot connection 432 such that the
anterior portion of the lower surface 436 of the upper mount member
430 can rest upon the cushion 470 during full extension.
[0095] Connected to the upper mount member 430 and the lower frame
member 420 is a spring or biasing member 440. The biasing member
440 can be made from any material that can provide the appropriate
biasing forces, such as the materials discussed above in section D.
According to one variation, the biasing member 440 is a carbon
fiber spring or member. The biasing member 440 has an upper end
442, a lower end 444, and can be constructed as a leaf spring, or
any other suitable shape that provides the appropriate biasing
forces, such as those discussed above in section D. The upper end
442 of the biasing member 440 is connected to the upper mount
member 430 at a second pivot connection 434. The second pivot
connection 434 is located posterior to the first pivot connection
432. The lower end 444 of the biasing member 440 is connected to
the lower frame member 420 at a third pivot connection 428. The
second and third pivot connections 434, 428 may be replaced with
any appropriate connection, as discussed above in section D.
[0096] In operation, the joint 410 may be used as a knee joint. The
joint 410 may be connected to a prosthetic leg (not shown) in any
conventional manner including, but not limited to, the standard
pyramid attachment system. The joint 410 is shown in full extension
in FIG. 8 with the lower surface 436 of the upper mount member 430
resting on the cushion 470. The cushion 470 provides stance flexion
during the stance phase. The cushion 470 can vary in size and
shape, and can contact the lower surface 436 across the entire
width, or merely a portion thereof, of the upper mount member 430.
Any suitable arrangement can be used in order to provide the
appropriate amount of stance flexion for each individual user.
[0097] The joint 410 is shown in maximum flexion in FIG. 9. This
position may occur while a user is seated. In order for a user to
go from a standing position to a seated position, the user must
brake the biasing member 440 over a pivot point. In other words, at
some point during the rotation of the upper mount member 430 from
the full extension position shown in FIG. 8 to the maximal flexion
position shown in FIG. 9, just after the resistance of the biasing
member 440 is at a maximum, the biasing member 440 will invert.
[0098] The inversion of the biasing member 440 changes how the
biasing member 440 biases the joint 410. In FIG. 8, the biasing
member 440 biases the joint 410 into the full extension position.
In FIG. 9, the biasing member 440 biases the joint 410 into the
maximal flexion position. This relationship effectively provides a
locking mechanism that is relatively easy to overcome. This
relationship generally locks the joint 410 into one of two
positions, but allows for flexion in both of the positions.
F. Fifth Embodiment
[0099] A fifth embodiment of an energy returning prosthetic joint
is illustrated in FIGS. 10, 11 and 12. In accordance with this
embodiment, the joint 510 is constructed very similarly to the
first embodiment. The joint 510 has a lower frame member 520
constructed from an appropriate material such as those capable of
providing lightweight structural support. Examples of such
materials include, but are not limited to, plastics, steel alloys,
aluminum alloys, other metals, ceramics, or other rigid materials.
The lower frame member 520 has a posterior surface 590, a first
interior surface 592, a second interior surface 594, and an
anterior surface 580. The lower frame member 520 also has a lower
portion 522, an upper portion 524, and a middle portion 526.
[0100] An upper mount member 530 is connected to the upper portion
524 of the lower frame member 520. The upper mount member 530 is
constructed of any suitable material such as those capable of
providing lightweight structural support. Examples of such
materials include, but are not limited to, plastics, steel alloys,
aluminum alloys, other metals, ceramics, or other rigid materials.
The connection between the upper mount member 530 and the upper
portion 524 of the lower frame member 520 is a first pivot
connection 532.
[0101] The joint 510 is mounted to a prosthetic member in any
conventional manner, such as by providing four threaded holes in
the lower frame member 520 and the upper mount member 530 that will
fit any standard prosthetic component. The prosthetic components
allow the joint 510 to be attached to upper and lower prosthetic
members (not illustrated).
[0102] Connected to the upper mount member 530 and the lower frame
member 520 is a spring or biasing member 540. The biasing member
540 can be made from any suitable lightweight material that can
provide the appropriate biasing forces, such as metals and
synthetic or composite materials. The materials selected for the
biasing member 540 should allow for bending of the biasing member
540 without permanent deformation of the biasing member 540.
Another factor in determining the appropriate material to be used
for the biasing member 540 is that the modulus of the material
should be selected to match the weight of the user and the desired
range of motion of the joint 510. Examples of appropriate materials
include, but are not limited to, spring steels, carbon or glass
fibers in resins, or specially treated plastics. To further control
the spring response, a polymer dampening material may be adhered to
the biasing member 540. According to one variation, the biasing
member 540 is a carbon fiber spring or member.
[0103] The biasing member 540 has an upper end 542, a lower end
544, a middle portion 546, a posterior surface 548 and an anterior
surface 549, and can be constructed as a leaf spring, or any other
suitable shape that provides the appropriate biasing forces. The
biasing member 540 could be, for example, formed in an "S" shape in
order to yield different response curves. The bending of an "S"
shaped biasing member 540 would require much less horizontal
displacement than, for example, a "C" shaped biasing member 540 for
the same amount of vertical displacement. The illustrated biasing
member 540 is formed as a leaf type spring and should be pre-bent
to control which direction the biasing member 540 will bend.
[0104] The upper end 542 of the biasing member 540 is connected to
the upper mount member 530 at a second pivot connection 534. The
second pivot connection 534 is located posterior to the first pivot
connection 532. The lower end 544 of the biasing member 540 is
connected to the lower frame member 520 at a third pivot connection
528. The pivot connection can be constructed in any appropriate
manner including, but not limited to, laminating the eye, bending
the biasing member 540 around the eye, clamping the biasing member
540 to the eye, or providing a rubber bushing vulcanized to the end
of the biasing member 540.
[0105] Further, the second pivot connection 534 could be replaced
with any appropriate connection including, but not limited to,
providing a spiral end at the upper end 542 of the biasing member
540. Additionally, the third pivot connection 528 can be replaced
with any appropriate connection including, but not limited to, a
rigid connection.
[0106] The energy returning prosthetic joint 510 also includes a
first damper 550 connected to the lower frame member 520 in any
suitable fashion, such as by bonding or mechanical fastening. The
first damper 550 can be made of any suitable material that can
absorb energy, for example a synthetic material such as a polymer.
The first damper 550 has a first end 552, a second end 554 and an
outer surface 556. The second end 554 of the first damper 550 is
connected to the first interior surface 592 at the middle portion
526 of the lower frame member 520, in any conventional manner.
[0107] The first damper 550 further includes a first opening 562 in
the first end 552, a second opening 564 in the second end 554 and a
first passageway 560 that extends through the first damper 550 from
the first opening 562 to the second opening 564. The sizes and
shapes of the first opening 262, second opening 564 and first
passageway 560 can be adjusted to change the volume of the first
damper 550, and hence the stiffness of the first damper 550. The
sizes and shapes of the first opening 562, second opening 564 and
first passageway 560 can also be adjusted to limit the amount of
airflow through the openings and the passageway, as will be
described in further detail below.
[0108] The first damper 550 also includes stiffness adjusting
mechanisms 258 located along the outer surface 556 of the first
damper 550. The stiffness adjusting mechanisms 558 can consist of
any structure that changes the volume and/or the geometry of the
first damper 550, such as grooves having any shape, notches and
tapers.
[0109] The lower frame member 520 additionally includes a second
passageway 570, located in the middle portion 226 of the lower
frame member 520. The second passageway 570 extends between the
posterior surface 590 of the lower frame member 520 and the first
interior surface 592 of the lower frame member 520, and is in
communication with the second opening 564 in the first damper 550.
This communication allows the passage of air from the first end 552
of the first damper 550, through the first opening 562, through
first passageway 560, through the second opening 564, through the
second passageway 570 to the environment past the posterior surface
590 of the lower frame member. The size and shape of the second
passageway 570 can be varied in order to adjust the amount of
airflow therethrough. The two passageways 560, 570, and the first
and second openings 562, 564 form an air vent that can be used to
adjust the energy return of the biasing member 540, as discussed
above in section D.
[0110] Additionally the location of the first end 552 of the first
damper 550 can be varied in relation to the posterior surface 548
of the biasing member 540 in order to allow for adjusting the rate
of release of the biasing member 540 from contact with the first
end 552 of the first damper 550.
[0111] Further, in this embodiment the anterior surface 580 of the
lower frame member 520 includes a clearance opening 582 that may
allow the biasing member 540, while in a flexed position, to extend
through the anterior surface 580 of the lower frame member 520, as
can be seen in FIG. 12.
[0112] In another variation, not shown, the anterior surface 580 of
the lower frame member 520 may not have the clearance opening 582,
but may be located such that when the biasing member 540 is in a
maximally flexed state, the anterior surface 549 of the biasing
member 540 does not contact the lower frame member 520.
[0113] In addition to the clearance opening 582, the lower frame
member 520 includes a second damper 550 disposed on the second
interior surface 594 of the lower frame member 520. The second
damper 550 has a first end 552, a second end 554, and an outer
surface 556. The second damper 550 may be connected to the second
interior surface 594 of the lower frame member 520 in any
conventional manner or, as illustrated, the second damper may have
a connection post 564 formed at the first end 552 of the second
damper 550. The second damper 550 may be constructed in a similar
manner as the first damper 550, including a passageway and an
opening through the first end 554, and a passageway through the
lower portion 522 of the lower frame member 520. Further, the
second damper 550 can be made of any suitable material that can
absorb energy, for example rubber, plastic or a synthetic material
such as a polymer.
[0114] The second damper 550 includes stiffness adjusting
mechanisms 558, as described above in section D, located on the
outer surface 556 of the second damper 550. The second damper 550
further includes an opening 562 in the second end 554 of the second
damper 550, and a passageway or hollow portion 560, partially
defined by the opening 562. This structure allows the volume, and
hence the stiffness, of the second damper 550 to be adjusted.
[0115] In operation, the joint 510 may be used as a knee joint. The
joint 210 is shown in full extension in FIG. 10, with the biasing
member 540 minimally flexed and the first damper 550 compressed.
The interaction of the biasing member 540 and the first damper 550
of the joint 510 functions in the same way as described above in
section B in reference to the third embodiment of the joint
310.
[0116] In FIG. 11, the joint 510 is shown in flexion of about 60
degrees. This position of the joint 510 may occur during the
toe-off phase. It can be seen that the anterior surface 549 of the
biasing member 540 is in contact with the second end 554 of the
second damper 550. In this manner the second damper 550 provides
resistance to the flexion of the biasing member 540 in order to
prevent too much flexion of the joint 510 during the toe-off phase.
As previously discussed, the volume, and hence the stiffness of the
second damper 550 can be adjusted in order to control the amount of
resistance the second damper 550 will provide to the flexion of the
biasing member 540.
[0117] The joint 510 is shown in maximum flexion of 90 degrees in
FIG. 12. This position may occur while a user is seated, and is
used in an exemplary way to show that during the maximal flexion of
the joint 510, the biasing member 540 no longer forms an airtight
seal with the first end 552 of the first damper 550. Instead, the
anterior surface 549 of the biasing member 540 is in contact with
the second end 554 of the second damper 550. As previously
discussed, the second damper 550 acts as a cushion and provides
resistance to the flexion of the biasing member 540 during the
toe-off phase, or as illustrated in FIG. 12, at a sitting
stage.
[0118] Further, as illustrated, the anterior surface 549 of the
biasing member 540 is in contact with the second end 554 of the
second damper 550 between the angles of 60 degrees and 90 degrees
during flexion. Similarly to the first damper 550, the location of
the second end 554 of the second damper 550, can be varied in order
to adjust the amount of resistance provided against the flexion of
the biasing member 540, and to vary the angles that the biasing
member 540 engages the second damper 550. All of the aforementioned
adjusting mechanisms allow the joint 510 to be adjustable to
different user's gait dynamics.
G. Alternate Embodiments
[0119] The energy returning prosthetic joint described in the three
exemplary embodiments herein is not limited to the specific
structures and components described, but is merely illustrative in
nature. As previously mentioned, numerous materials may be used in
the construction of the energy returning prosthetic joint,
including, but not limited to, carbon fiber, glass fiber, titanium,
stainless steel, aluminum alloys, resins, and epoxies.
[0120] The orientation of the joints may be reversed, as in the
embodiment of FIGS. 3 and 4, wherein the described anterior side
may be reversed to define the posterior side, and the described
posterior side would therefore be reversed to denote the anterior
side.
[0121] Numerous modifications to the disclosed embodiments may
occur to those skilled in the art. Such modifications are meant to
be included by this disclosure, and the only limitations meant to
be included are those contained in the appended claims.
* * * * *