U.S. patent application number 10/977899 was filed with the patent office on 2005-03-31 for universal prosthesis with cushioned ankle.
Invention is credited to Phillips, Van L., Pouchak, Hilary D..
Application Number | 20050071018 10/977899 |
Document ID | / |
Family ID | 33302537 |
Filed Date | 2005-03-31 |
United States Patent
Application |
20050071018 |
Kind Code |
A1 |
Phillips, Van L. ; et
al. |
March 31, 2005 |
Universal prosthesis with cushioned ankle
Abstract
The invention provides a cushioned ankle prosthetic foot and a
cosmesis having a slot between the big toe and adjacent toe to
allow the amputee to wear thong sandals and the like. The
cushioning desirably provides a smooth and more natural-feeling
rollover from a heel-strike to a toe-off position and/or improved
dynamic response characteristics. Advantageously, the prosthetic
foot is configured so that it can be used as either a right or a
left foot. Moreover, the cosmesis includes a toe reinforcement
strap to desirably provide improved wear resistance to the
cosmesis.
Inventors: |
Phillips, Van L.; (Albion,
CA) ; Pouchak, Hilary D.; (Carlsbad, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
33302537 |
Appl. No.: |
10/977899 |
Filed: |
October 29, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10977899 |
Oct 29, 2004 |
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09586666 |
Jun 1, 2000 |
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6811571 |
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60201150 |
May 2, 2000 |
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Current U.S.
Class: |
623/52 ;
623/55 |
Current CPC
Class: |
A61F 2002/6628 20130101;
A61F 2002/5001 20130101; A61F 2002/6685 20130101; A61F 2002/7862
20130101; A61F 2002/30462 20130101; A61F 2002/30433 20130101; A61F
2/76 20130101; A61F 2002/665 20130101; A61F 2/66 20130101; A61F
2002/5007 20130101; A61F 2220/0041 20130101; A61F 2002/6621
20130101; A61F 2220/0075 20130101 |
Class at
Publication: |
623/052 ;
623/055 |
International
Class: |
A61F 002/66 |
Claims
What is claimed is:
1. A prosthetic foot, comprising: a foot element comprising a toe
region comprising a toe and an adjacent slot that only extends
within said toe region; an ankle element positioned entirely above
said foot element and spaced from said foot element; and an ankle
block comprising a compressible material and positioned
intermediate said foot element and said ankle element such that
said foot element and said ankle element do not directly contact
one another.
2. The prosthetic foot of claim 1, wherein said toe and said slot
have the same length.
3. The prosthetic foot of claim 1, wherein said foot element has an
upper surface and said ankle element has a lower surface that is
substantially parallel to said upper surface of said foot
element.
4. The prosthetic foot of claim 1, wherein said ankle block
comprises a monolithic element.
5. The prosthetic foot of claim 1, wherein said foot element
comprises an integral unit.
6. The prosthetic foot of claim 1, wherein said foot element is
generally curvilinear in shape.
7. The prosthetic foot of claim 1, wherein said ankle element is
shorter than said foot element.
8. The prosthetic foot of claim 1, wherein said prosthetic foot
further comprises a connector for facilitating attachment of said
prosthetic foot to a socket or pylon.
9. The prosthetic foot of claim 1, wherein said prosthetic foot
further comprises a cosmesis that includes a slot substantially
aligned with said slot of said foot element.
10. The prosthetic foot of claim 1, wherein at least one of said
foot element and said ankle element is flexible.
11. A prosthetic foot, comprising: a foot element having a
longitudinal axis and comprising a plurality of toes at an anterior
toe region, said plurality of toes comprising two side toes and an
intermediate central toe separated from said side toes by
respective slots, said central toe being parallel to and aligned
with said longitudinal axis, said toes having the same length and
said slots extending entirely within said anterior toe region; an
ankle element spaced from said foot element and being connectable
to a lower limb socket or pylon; and a compressible ankle block
sandwiched between said foot element and said ankle element.
12. The prosthetic foot of claim 11, wherein said ankle element is
positioned entirely above said foot element.
13. The prosthetic foot of claim 11, wherein said foot element and
said ankle element do not directly contact one another.
14. The prosthetic foot of claim 11, wherein said ankle block
comprises a wedged configuration.
15. The prosthetic foot of claim 14, wherein said wedged
configuration comprises a wedge shaped cut at a posterior section
of said ankle block.
16. The prosthetic foot of claim 11, wherein said toes are slightly
upwardly curved.
17. The prosthetic foot of claim 11, wherein said toes have a
length of about 1.5 inches or less.
18. The prosthetic foot of claim 11, wherein said ankle block is in
mechanical communication with an arch region of said foot
element.
19. The prosthetic foot of claim 11, wherein said prosthetic foot
further comprises an outer cosmesis that houses said foot element,
said ankle element and said ankle block.
20. The prosthetic foot of claim 19, wherein said cosmesis
comprises a toe region with a slot to form a big toe substantially
aligned with one of said side toes of said foot element.
21. A prosthetic foot, comprising: a foot element comprising an
anterior toe region comprising a middle toe and a pair of flanking
outer toes, each of said toes having geometrically substantially
the same shape; an ankle element positioned above said foot element
and spaced from said foot plate over an entire length of said ankle
plate; at least one of said foot element and said ankle element
being capable of flexing along their length; and a resilient ankle
block intermediate said foot element and said ankle element, said
ankle block comprising a posterior section having a wedge shaped
cut to form a generally vertical first rear face and a sloping
second rear face downwardly inclined with respect to said first
rear face.
22. The prosthetic foot of claim 21, wherein said toes only extend
within said anterior toe region.
23. The prosthetic foot of claim 21, wherein said ankle element is
positioned entirely above said foot element.
24. The prosthetic foot of claim 21, wherein said toes are
symmetrically arranged.
25. The prosthetic foot of claim 21, wherein said foot element is
generally curvilinear.
26. The prosthetic foot of claim 21, wherein said ankle block
comprises an anterior section that has a sloping front face.
27. The prosthetic foot of claim 21, wherein said ankle block
comprises an elastomer.
28. The prosthetic foot of claim 27, wherein said ankle block
comprises polyurethane.
29. The prosthetic foot of claim 28, wherein said ankle block
comprises polyurethane foam.
30. The prosthetic foot of claim 21, wherein said ankle block
comprises cellular foam.
31. The prosthetic foot of claim 21, wherein said foot element and
said ankle element do not directly contact one another.
32. A prosthetic foot, comprising: a generally horizontal foot
plate comprising a toe region comprising an asymmetric slot and an
adjacent toe, said slot and said toe being positioned entirely
within said toe region; an ankle plate positioned entirely above
said foot plate and spaced from said foot plate; and a compressible
ankle block positioned intermediate said foot plate and said ankle
plate such that said foot plate and said ankle plate do not
directly contact one another.
33. The prosthetic foot of claim 32, wherein said foot plate has a
longitudinal axis and said slot is offset from said longitudinal
axis.
34. The prosthetic foot of claim 33, wherein said toe is offset
from said longitudinal axis.
35. The prosthetic foot of claim 32, wherein at least one of said
foot plate and said ankle plate is flexible.
36. The prosthetic foot of claim 32, wherein said ankle block
comprises substantially the sole means of support and connection
between said foot plate and said ankle plate.
37. The prosthetic foot of claim 32, wherein said ankle block
comprises a wedged configuration.
38. The prosthetic foot of claim 37, wherein said wedged
configuration comprises a wedge shaped cut at a posterior section
of said ankle block.
39. The prosthetic foot of claim 32, wherein said prosthetic foot
further comprises a cosmesis that includes a slot substantially
aligned with said slot of said foot plate.
40. The prosthetic foot of claim 32, wherein said ankle plate is
generally horizontal.
41. The prosthetic foot of claim 32, wherein said foot plate
extends a length substantially equal to that of a natural foot.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 09/586,666, filed Jun. 1, 2000, now U.S. Pat.
No. 6,811,571, issue date Nov. 2, 2004, which claims the benefit of
U.S. Provisional Patent Application Ser. No. 60/201,150, filed May
2, 2000, the entirety of each one of which is hereby incorporated
by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to prosthetic feet
and, more particularly, to a prosthetic foot having a cushioned
ankle and a thong-receiving reinforced outer foot cosmesis.
[0004] 2. Description of the Related Art
[0005] In the prosthetics market, the conventional SACH foot has
been the most widely prescribed artificial foot over the past
several decades. The SACH foot generally includes a solid ankle and
cushioned heel foot mounted to a limb along an approximate hinge
axis taken through the ankle. The SACH foot has been popular
precisely for its simplicity, and thus economy, but includes
certain drawbacks in terms of dynamic response characteristics.
Specifically, the low end SACH feet do not provide much energy
storage and release, as do more sophisticated prosthetic feet.
[0006] Some patients undergo what is known in the art as a Symes
amputation, where the foot is severed from the leg near the ankle
region. Because the Symes patient's calf and shin function as the
stump for prosthetic purposes, prosthetic devices utilized by the
patient must either be relatively compact, so as to be attachable
below the point of amputation, or must be configured to accommodate
the patient's shin and calf while attached thereto or higher up on
the wearer's leg.
[0007] Prior art prostheses available to Symes patients typically
include an artificial foot bonded or bolted onto the bottom end of
a socket worn on a patient's stump. These compact prosthetic feet
can also attach below a downwardly depending pylon secured to a
socket higher up on the amputee's leg. For such compact prostheses,
it is difficult to provide the level of dynamic response
approximating the original ankle and foot due to the lack of
vertical space available.
[0008] Some attempts at providing the appropriate response
characteristics of the original ankle and foot in Symes foot
prosthesis involve the use of rubber cushions, or bumpers, between
a lower leg and the foot. Many of these require a pivotable bolt
attachment between the leg and the foot. Unfortunately, many of
these rubber cushion devices have limited durability due to the
difficulty in bonding the rubber portions to the solid leg or foot
portions, or are relatively complex, requiring several machined
parts, which adds to the cost.
[0009] U.S. Pat. Nos. 5,800,569 and 5,993,488, incorporated by
reference herein, to Phillips disclose a resilient ankle block
prosthesis that mitigates or overcomes some of the above
disadvantages. But, there is still room for further improvements in
providing a smooth and more natural-feeling rollover from a
heel-strike to a toe-off position and/or of providing improved
dynamic response characteristics, so as to provide a natural
feeling foot during walking or running activities.
[0010] There are also a number of foot cosmesis that are presently
commercially available in the market. The cosmesis for an
artificial foot serves as a cosmetic outer cover and provides the
appearance of a relatively natural looking foot for the lower limb
amputee.
[0011] Conventional artificial feet and/or cosmesis can
disadvantageously also be limited in terms of the flexibility and
versatility they provide in allowing the amputee to don different
types of conventional footwear. Moreover, the frictional contact
between the artificial foot and the cosmesis can cause wear of the
cosmesis, especially at the high stress contact points. This can
not only result in inconvenient frequent replacement of the
cosmesis but also further adds to the cost for the amputee.
Additionally, many artificial feet are adapted to be used only as a
left or right foot and not both, and this undesirably limits
versatility and increases manufacturing and inventory costs.
[0012] Consequently, there is a need for a relatively inexpensive,
durable and versatile prosthetic foot assembly with improved
performance characteristics.
SUMMARY OF THE INVENTION
[0013] Accordingly, it is one object and advantage of the present
invention to overcome some or all of the above limitations by
providing a cushioned ankle prosthetic foot and an associated
cosmesis having a slot between the big toe and adjacent toe to
allow the amputee to wear thong sandals and the like. The
cushioning desirably provides a smooth and more natural-feeling
rollover from a heel-strike to a toe-off position and/or improved
dynamic response characteristics. Advantageously, the prosthetic
foot is configured so that it can be used as either a right or a
left foot. Moreover, the cosmesis includes a toe reinforcement
strap to desirably provide improved wear resistance to the
cosmesis.
[0014] In accordance with one preferred embodiment of the
invention, a prosthetic foot assembly for a lower limb amputee is
provided. The assembly generally comprises a prosthetic foot and an
outer cosmesis. The prosthetic foot attaches to a socket or pylon
of the lower limb amputee. The prosthetic foot generally comprises
a lower foot plate and an upper ankle plate. The lower foot plate
includes a symmetric toe configuration and a plurality of slots
formed therebetween. The upper ankle plate has a length
substantially shorter than the foot plate. The prosthetic foot
further comprises an ankle block having a wedged configuration. The
ankle block comprises a compressible material and is sandwiched
between the foot plate and the ankle plate. The outer cosmesis has
a length approximately equal to the length of a natural human foot
and has an anterior toe region including a slot substantially
aligned with one of the slots of the foot plate. Advantageously,
the prosthetic foot assembly permits the lower limb amputee to wear
thong sandals and the like and/or provides enhanced performance
characteristics.
[0015] In accordance with another preferred embodiment of the
invention, an outer foot cosmesis is provided. The outer foot
cosmesis has a length substantially the same as that of a natural
human foot. The cosmesis comprises an inner cavity for receiving a
prosthetic foot for attaching to a socket or pylon of a lower limb
amputee. The cosmesis has a toe portion comprising at least one
slot for receiving a thong of a sandal or other footwear. The
cosmesis further comprises a reinforcement patch in the toe portion
for improving the wear resistance of the cosmesis.
[0016] For purposes of summarizing the invention and the advantages
achieved over the prior art, certain objects and advantages of the
invention have been described herein above. Of course, it is to be
understood that not necessarily all such objects or advantages may
be achieved in accordance with any particular embodiment of the
invention. Thus, for example, those skilled in the art will
recognize that the invention may be embodied or carried out in a
manner that achieves or optimizes one advantage or group of
advantages as taught herein without necessarily achieving other
objects or advantages as may be taught or suggested herein.
[0017] All of these embodiments are intended to be within the scope
of the invention herein disclosed. These and other embodiments of
the present invention will become readily apparent to those skilled
in the art from the following detailed description of the preferred
embodiments having reference to the attached figures, the invention
not being limited to any particular preferred embodiment(s)
disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a simplified partially sectional side elevation
view of a prosthetic foot assembly having features in accordance
with one preferred embodiment of the present invention.
[0019] FIG. 2 is a simplified partially sectional top plan view of
the prosthetic foot assembly of FIG. 1.
[0020] FIG. 3 is a simplified rear view of the prosthetic foot of
FIG. 1.
[0021] FIG. 4 is a top plan view of a lower foot plate of the
prosthetic foot assembly of FIG. 1 having features in accordance
with one preferred embodiment of the present invention.
[0022] FIG. 5 is a side elevation view of the lower foot plate of
FIG. 4.
[0023] FIG. 6 is a perspective view of an upper ankle plate of the
prosthetic foot assembly of FIG. 1 having features in accordance
with one preferred embodiment of the present invention.
[0024] FIG. 7 is a top plan view of the upper ankle plate of FIG.
6.
[0025] FIG. 8 is a sectional view along line 8-8 of FIG. 7.
[0026] FIG. 9 is a sectional view along line 9-9 of FIG. 7.
[0027] FIG. 10 is a perspective view of a compressible ankle block
of the prosthetic foot assembly of FIG. 1 having features in
accordance with one preferred embodiment of the present
invention.
[0028] FIG. 11 is a top plan view of the compressible ankle block
of FIG. 10.
[0029] FIG. 12 is a side elevation view of the compressible ankle
block of FIG. 10.
[0030] FIG. 13 is a sectional view of an outer cosmesis (along
substantially a longitudinal axis of the cosmesis) of the
prosthetic foot assembly of FIG. 1 having features in accordance
with one preferred embodiment of the present invention.
[0031] FIG. 14 is a sectional view along line 14-14 of FIG. 13.
[0032] FIG. 15 is a perspective view of the outer cosmesis of FIG.
13.
[0033] FIG. 16 is a bottom plan view (showing some hidden lines) of
the outer cosmesis of FIG. 13.
[0034] FIG. 17 is a perspective view of a reinforcement patch of
the cosmesis of FIG. 13.
[0035] FIG. 18 is a top plan view of the reinforcement patch of
FIG. 17.
[0036] FIG. 19 is a rear view of the reinforcement patch of FIG.
17.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0037] FIGS. 1 and 2 illustrate a prosthetic or artificial foot
assembly or combination 10 having features in accordance with one
preferred embodiment of the present invention. The prosthetic foot
assembly or foot prosthesis 10 generally comprises a prosthetic or
artificial foot 12 and an outer foot cover or cosmesis 14. For
clarity, a sectional illustration of the cosmesis 14 is shown in
FIGS. 1 and 2. FIG. 3 is a rear view of the prosthetic foot 12.
[0038] The prosthetic foot or prosthesis 12 generally comprises a
lower foot plate 20, an upper, smaller ankle plate 22, and a layer
or block 24 of resilient material sandwiched between and connecting
the foot plate 20 to the ankle plate 22. In one preferred
embodiment, the lower foot plate 20 comprises a symmetric toe
configuration, thereby desirably permitting the prosthetic foot 12
to be used as either a left or right foot. Advantageously, this
saves on manufacturing and inventory costs.
[0039] Preferably, and as discussed in greater detail below, the
intermediate ankle block 24 is bonded to the foot plate 20 and
ankle plate 22. Preferably, and as also discussed in greater detail
below, the foot plate 20 and the ankle plate 22 comprise a strong,
flexible material. Advantageously, during a walking and/or running
stride, the combination of the resilient ankle block or keel 24 and
the flexible plates 20, 22 provides a smooth rollover from a
heel-strike to a toe-off position.
[0040] In one preferred embodiment, a limit strap 26 is used to
further secure the foot plate 20, the ankle block 24 and the ankle
plate 22. The limit strap 26 controls or limits the maximum degree
of displacement (expansion) of the ankle block 24 and the relative
motion between the foot plate 20 and the ankle plate 22 proximate
the heel portion of the prosthesis 12.
[0041] Preferably, the ankle or connector plate 22 is coupled to an
attachment member 28 for coupling the prosthetic foot 12 to a
downwardly depending leg such as a stump or lower-limb pylon of the
amputee or wearer. The ankle plate 22 is preferably connected to
the attachment member 28 utilizing a bolt 30 and a washer 32. The
center or longitudinal axis of the bolt 30 defines an attachment
axis 34 which is generally aligned with the vertical centerline of
an imaginary ankle so as to more faithfully simulate the location
at which forces are transmitted between leg and foot.
[0042] The cosmesis or foot cover 14 is generally shaped, sized
and/or configured to generally emulate the appearance of a natural
human foot. The cosmesis 14 is preferably constructed of a
resilient material. Preferably, the cosmesis 14 comprises an inner
cavity 40 shaped, sized and/or configured to receive the prosthetic
foot 12.
[0043] In one preferred embodiment, the cosmesis 14 comprises a
slit or slot 42 (FIG. 2) in the toe region to receive a thong or
the like of a thong sandal or other footwear. Desirably, this adds
to the versatility of the invention. The cosmesis 14 preferably
further comprises a reinforcement patch or strap 44 in or near the
toe region to provide durability.
[0044] A supporting ground or floor surface 36 is also shown in
FIG. 1. The spacing or gap between the cosmesis 14 (or prosthetic
foot assembly 10) and the surface 36 and the orientation of the
cosmesis 14 relative to the surface 36 are indicative of an
intermediate sole and/or heel of a shoe or other footwear worn by
the amputee. Those of ordinary skill in the art will recognize that
when the amputee is not wearing a shoe or other footwear, the
cosmesis 14 can be in direct contact with the ground or floor
surface 36.
[0045] As is known in the art, see for example U.S. Pat. Nos.
5,800,569 and 5,993,488, incorporated by reference herein,
ambulation comprises several foot positions with respect to a
supporting ground or floor surface. The several walking and/or
running strides include a heel-strike position, a generally
flat-foot position, a heel-off position and a toe-off position.
Throughout these various stride positions, the prosthetic foot 12
of the invention advantageously provides a smooth and generally
life-like response to the wearer. During a walking and/or running
stride, the ankle block 24 transmits the forces imparted thereon by
the foot plate 20 and the ankle plate 22, and experiences a gradual
rollover, or migration of the compressed region, from rear to
front.
[0046] Lower Foot Plate
[0047] In one preferred embodiment, and referring in particular to
FIGS. 4 and 5, the lower or bottom foot plate or member 20
generally comprises an anterior toe region or portion 46, a medial
arch region or portion 48 and a posterior heel region or portion
50. Preferably, the foot plate 20 has a curvilinear shape (FIG. 4),
including a slight arch in the center section 48 and a slightly
upwardly curved toe section 46 and heel section 50. Desirably, this
generally simulates the natural curve of the sole of a human
foot.
[0048] The curvature(s) of the lower surface of the foot plate 20
generally corresponds to the profile of an associated contacting
surface of the cosmesis 14 and/or to the profile of an associated
shoe sole. The curvature(s) of the upper surface of the foot plate
20 generally corresponds to selected ranges of human lengths.
Optionally, the foot plate 20 can comprise a generally flat plate,
as needed or desired.
[0049] Preferably, the foot plate 20 has a thickness along its
length that is tapered, and the tapered profile corresponds
approximately to the weight of the amputee. That is, for a heavier
weight group amputee, the thickness along the length of the foot
plate 20 would be generally greater than that for a lighter weight
group amputee.
[0050] The foot plate 20 preferably has a length and width roughly
equal to or slightly smaller than the approximate length and width
of the particular wearer's amputated foot and is sized, shaped
and/or configured to fit within the outer flexible cosmesis 14.
Preferably, and as shown in FIG. 4, the width of the foot plate 20
is greater towards the front and follows a curved profile to define
a maximum width (W) at or near the junction between the toe region
46 and the arch region 48. Desirably, this simulates the
approximate shape or contour of a natural foot. Optionally, foot
plate 20 may include a lower sole cushion to provide protection to
the inner surfaces of the cosmesis 14.
[0051] In other preferred embodiments, the foot plate 20 can be
shaped, sized and/or configured in alternate manners with efficacy,
as required or desired, giving due consideration to the goals of
providing a suitably strong and generally natural feeling
prosthetic foot, and/or of achieving one or more of the advantages
and benefits as taught or suggested herein.
[0052] The lower foot plate 20 is preferably capable of flexing
along its length. Desirably, the flexing of the foot plate 20 under
the weight of the amputee tends to distribute and/or relieve shear
stresses applied at the interface between the foot plate 20 and
ankle block 24. Moreover, the flexing contributes to a more natural
feeling walking and/or running stride for the wearer of the
prosthetic foot 12.
[0053] In one preferred embodiment, the toe or front section 46 of
the foot plate 20 comprises a plurality of generally elongated
spaced toes 52. Most preferably, the toe section 46 comprises three
toes 52 (labeled 52a, 52b, 52c) and two corresponding slots 54
(labeled 54a, 54b) formed therebetween. In other preferred
embodiments, the toe section 46 can efficaciously comprise fewer or
more toes, as required or desired, giving due consideration to the
goals of achieving one or more of the advantages and benefits as
taught or suggested herein. Optionally, the toe section 46 may not
be slotted to form individual toes and/or the foot plate 20 may
comprise a generally flat plate, as needed or desired.
[0054] In one preferred embodiment, the toes 52a, 52b, 52c (and
hence the slots 54a, 54b) are arranged to form a generally
symmetric configuration about a longitudinal axis 56 of the foot
plate 20. Desirably, this allows the foot plate 20 to be used as
part of a left or right prosthetic foot 12. In other preferred
embodiments, the toes 52 and slots 54 can be efficaciously arranged
in alternate configurations, as required or desired, giving due
consideration to the goals of achieving one or more of the
advantages and benefits as taught or suggested herein.
[0055] The slots 54 (and toes 52) are sized, shaped and/or
configured so that when the foot plate 20 is seated in the cosmesis
14, a respective one of the slots 54a, 54b is substantially aligned
with the thong-receiving slot 42 (FIG. 2). The particular toe slot
54a or 54b that is aligned with the cosmesis slot 42 (and a
corresponding slot of the reinforcement patch 44) depends on
whether the cosmesis 14 is a right or left foot cosmesis. For
illustration purposes, a right foot cosmesis 14 is shown in FIG. 2
in which the toe slot 54a is aligned with the cosmesis slot 42,
though the skilled artisan will realize that a left foot cosmesis
is substantially a mirror image of a right foot cosmesis in which
the toe slot 54b will be aligned with the corresponding cosmesis
slot.
[0056] Advantageously, the symmetric toe configuration of the foot
plate 20 allows the prosthetic foot 12 to be readily used in
conjunction with a cosmesis 14 of a right or left foot. Desirably,
this saves on manufacturing and inventory costs, and also adds to
the versatility of the invention.
[0057] Preferably, the outer toes 52a, 52b are slightly inwardly
curved towards the foot plate longitudinal axis 56 and the center
or middle toe 52c is substantially aligned with the longitudinal
axis 56. In other preferred embodiments, the toes 52 and slots 54
can be efficaciously arranged in alternate configurations, as
required or desired, giving due consideration to the goals of
achieving one or more of the advantages and benefits as taught or
suggested herein.
[0058] Each one of the toes 52 preferably includes a marker 58
(labeled 58a, 58b, 58c in FIG. 4) in the form of a slightly raised
crosswise portion, rib or bump on each of the upper surfaces of the
toes 52. As discussed below, the location of the markers 58
generally corresponds to a smaller foot size. This allows the
portion of the toes 52 extending beyond the bumps 58 to be trimmed
down to form a foot plate 20 for a smaller or intermediate foot
size. Advantageously, this saves on manufacturing and inventory
costs.
[0059] In another preferred embodiment, the markers or indicators
58 can comprise grooves. In yet another preferred embodiment, the
markers 58 comprise bands which are colored to provide visual
differentiation. In other preferred embodiments, as the skilled
artisan will recognize, the markers 58 can be alternately formed
and/or constructed with efficacy, as required or desired, giving
due consideration to the goals of providing size indicating means,
and/or of achieving one or more of the advantages and benefits as
taught or suggested herein.
[0060] The toe portion 46 has a toe end 60 and is preferably
slightly uplifted or generally concave-upward relative to a
generally horizontal plane P.sub.1 tangential to the toe section
46, as shown in FIG. 5. As indicated before, the curvature of the
toe portion 46 generally simulates the natural curve of the toe
region of the sole of a human foot. In other preferred embodiments,
the toe region 46 can be efficaciously configured in alternate
manners, as required or desired, giving due consideration to the
goals of providing a generally natural feeling prosthetic foot 12,
and/or of achieving one or more of the advantages and benefits as
taught or suggested herein.
[0061] The heel or rear section or portion 50 has a heel end 62 and
is preferably slightly uplifted or generally concave-upward
relative to a generally horizontal plane P.sub.2. The plane P.sub.2
is substantially parallel to and slightly raised, offset or
elevated by a predetermined distance (D.sub.12) relative to the
plane P.sub.1. As indicated before, the curvature of the heel
portion 50 generally simulates the natural curve of the heel region
of the sole of a human foot. In other preferred embodiments, the
heel region 50 can be efficaciously configured in alternate
manners, as required or desired, giving due consideration to the
goals of providing a generally natural feeling prosthetic foot 12,
and/or of achieving one or more of the advantages and benefits as
taught or suggested herein.
[0062] It is understood that within the cosmesis 14 (FIG. 1), the
heel plane P.sub.2 is raised by a distance D.sub.12 relative to the
toe plane P.sub.1. The magnitude of D.sub.12 is largely determined
by the particular configuration of the cosmesis 14 and/or that of
the sole and heel of the shoe or other footwear donned by the
wearer. For example, for a higher shoe heel the distance D.sub.12
will be larger as compared to for a shorter shoe heel.
[0063] The central or middle arch section 48 is intermediate or
between the toe section 46 and the heel section 50 and is
preferably generally concave downward. As indicated before, the
curvature of the arch portion 48 generally simulates the natural
curve of the arch region of the sole of a human foot. The regions
of the arch section 48 proximate to the toe section 46 and heel
section 50 can be slightly concave upward. In other preferred
embodiments, the central region 48 can be efficaciously configured
in alternate manners, as required or desired, giving due
consideration to the goals of providing a generally natural feeling
prosthetic foot 12, and/or of achieving one or more of the
advantages and benefits as taught or suggested herein.
[0064] In one preferred embodiment, the arch section 48 comprises a
substantially flat upper surface 64 adjacent to the heel section
50. In other preferred embodiments, the central region 48 can be
efficaciously configured in alternate manners, as required or
desired, giving due consideration to the goals of providing a
generally natural feeling prosthetic foot 12, and/or of achieving
one or more of the advantages and benefits as taught or suggested
herein.
[0065] In general or on the average, the arch section 48 of the
foot plate 20 is thicker than the other sections of the foot plate
20. In other preferred embodiments, the central arch region 48 can
be efficaciously dimensioned in alternate manners, as required or
desired, giving due consideration to the goals of providing a
generally natural feeling prosthetic foot 12, and/or of achieving
one or more of the advantages and benefits as taught or suggested
herein.
[0066] In one preferred embodiment, the upper surface of the arch
section 48 comprises a location rib or bump 66 for establishing the
relative positioning between the foot plate 20 and the ankle block
24. The location bump 66 mates with or engages a corresponding
groove on the lower surface of the ankle block 24. The rib 66 may
also provide added protection against separation, peeling or
delamination between the foot plate 20 and the ankle block 24.
[0067] Alternatively, the location rib may be provided on the ankle
block 24 and the corresponding groove may be provided on the foot
plate 20. Additionally, other positioning means such as location
pins and the like may be efficaciously used, as required or
desired, giving due consideration to the goals of establishing the
desired positioning between the foot plate 20 and the ankle block
24, and/or of achieving one or more of the advantages and benefits
as taught or suggested herein.
[0068] Preferably, the location rib 66 extends crosswise across the
span of the upper surface of the foot plate 20. In other preferred
embodiments, the rib 66 (and corresponding groove) can be
positioned and configured in alternate manners with efficacy, as
required or desired, giving due consideration to the goals of
establishing the desired positioning between the foot plate 20 and
the ankle block 24, and/or of achieving one or more of the
advantages and benefits as taught or suggested herein.
[0069] Preferably, the foot plate 20 is fabricated from a vinyl
ester based sheet molding compound, such as Quantum QC-8800,
available from Quantum Composites of Midland, Mich. The foot plate
20 preferably comprises a vinyl ester resin matrix with a
substantially randomly arranged fiberglass fiber content. In
another preferred embodiment, the foot plate 20 is constructed of
fiberglass. Alternatively, the foot plate 20 may be formed by a
plurality of lamina embedded in a hardened flexible polymer. The
foot plate 20 can also be formed of carbon fibers.
[0070] In other arrangements, the foot plate 20 may be formed of
alternate suitable materials, such as other composite materials,
plastics, thermoplastic and thermosetting polymers, metals, alloys
and ceramics among others, as required or desired, giving due
consideration to the goals of achieving one or more of the
advantages and benefits as taught or suggested herein. The
desirable properties of the foot plate 20 are that it is relatively
resilient so as to withstand cracking upon application of repeated
bending stresses, yet has sufficient flexibility to enhance the
performance characteristics felt by the wearer, in conjunction with
the properties of the resilient ankle block 24 and the ankle plate
22.
[0071] Preferably, the foot plate 20 is formed by a molding
process. More preferably, the foot plate 20 is formed by a
compression molding process. Alternatively, the foot plate 20 can
be formed by an injection molding process. In other preferred
embodiments, the foot plate 20 can be fabricated using other
techniques, for example, machining, welding, laminating, casting
and forging among others, with efficacy, as required or desired,
giving due consideration to the goals of providing enhanced
performance, and/or of achieving one or more of the advantages and
benefits as taught or suggested herein.
[0072] TABLES 1A-1B below, in accordance with one preferred
embodiment, list various approximate dimensions of the foot plate
20 for various amputee foot and weight sizes. The number and letter
in the "SIZE" column in TABLES 1A-1B respectively refer to the
cosmesis size or overall length in centimeters and the weight group
(L=Light, M=Medium, H=Heavy) of the amputee. The other column
heading symbols in TABLES 1A-1B refer to dimensional labels as
marked on FIGS. 4-5. T1 to T11 refer to thicknesses (in inches), A,
B, L, N, O, P, X, Y refer to length scales (in inches), W refers to
a width (in inches), R1, R2, R3, I, J, K refer to radii of
curvature (in inches) and D refers to an angle in degrees
(.degree.). Note that the thicknesses T1 to T11 are taken at
positions spaced by the corresponding value of Y, that is, the
position at which T1 is taken is spaced from the position where T2
is taken by Y, and so on. It will be appreciated that other
dimensions than those of TABLES 1A-1B may be used, as needed or
desired.
1TABLE 1A FOOT PLATE DIMENSIONS FOR DIFFERENT AMPUTEE SIZES
(CORRESPONDS TO FIGS. 4 AND 5) SIZE A B D R1 R2 R3 I J K L N O P
22L 2.75 3.00 18.0.degree. 5.75 5.75 .19 .75 6.50 5.25 7.27 3.250
1.423 .94 22H 2.75 3.00 18.0.degree. 5.75 5.75 .19 .75 6.50 5.25
7.27 3.250 1.423 .94 24L 3.00 3.25 16.0.degree. 7.00 7.00 .19 .82
7.00 5.75 8.06 3.640 1.650 1.10 24M 3.00 3.25 16.0.degree. 7.00
7.00 .19 .82 7.00 5.75 8.06 3.640 1.650 1.10 24H 3.00 3.25
16.0.degree. 7.00 7.00 .19 .82 7.00 5.75 8.06 3.640 1.650 1.10 26L
3.25 3.50 13.0.degree. 8.75 8.75 .25 .88 7.63 6.25 8.85 4.000 1.860
1.26 26M 3.25 3.50 13.0.degree. 8.75 8.75 .25 .88 7.63 6.25 8.85
4.000 1.860 1.26 26H 3.25 3.50 13.0.degree. 8.75 8.75 .25 .88 7.63
6.25 8.85 4.000 1.860 1.26 28L 3.50 3.75 13.5.degree. 9.50 9.50 .25
.95 8.25 6.77 9.60 4.398 1.981 1.50 28H 3.50 3.75 13.5.degree. 9.50
9.50 .25 .95 8.25 6.77 9.60 4.398 1.981 1.50
[0073]
2TABLE 1B FOOT PLATE DIMENSIONS FOR DIFFERENT AMPUTEE SIZES
(CORRESPONDS TO FIGS. 4 AND 5) SIZE W X Y T1 T2 T3 T4 T5 T6 T7 T8
T9 T10 T11 22L 2.082 2.60 .79 .064 .089 .169 .224 .233 .221 .207
.170 .146 .117 .107 22H 2.082 2.60 .79 .078 .103 .183 .238 .247
.235 .221 .184 .160 .131 .121 24L 2.250 2.70 .86 .066 .092 .175
.232 .241 .228 .214 .176 .151 .121 .111 24M 2.250 2.70 .86 .080
.106 .189 .246 .255 .242 .228 .190 .165 .135 .125 24H 2.250 2.70
.86 .095 .121 .204 .261 .270 .257 .243 .205 .180 .150 .140 26L
2.417 2.75 .93 .083 .109 .195 .253 .262 .249 .235 .196 .170 .139
.129 26M 2.417 2.75 .93 .098 .124 .210 .268 .277 .264 .250 .211
.185 .154 .144 26H 2.417 2.75 .93 .119 .145 .231 .289 .298 .285
.271 .232 .206 .175 .165 28L 2.600 2.60 1.00 .101 .127 .216 .275
.285 .271 .257 .217 .190 .158 .148 28H 2.600 2.60 1.00 .122 .148
.237 .296 .306 .292 .278 .238 .211 .179 .169
[0074] TABLE 2 below lists intermediate amputee foot sizes which
can utilize foot plates 20 which are trimmed down from the standard
sizes of TABLES 1A-1B. As discussed above, markers 58 which are
already formed on the foot plate toes 52 facilitate this trim-down
process. Advantageously, such a scheme saves on manufacturing and
inventory costs.
3TABLE 2 FOOT PLATE INTERMEDIATE TRIM DOWN SIZES TRIM DOWN FROM
FOOT SIZE PLATE FOR SIZE 21L 22L 21H 22H 23L 24L 23M 24M 23H 24H
25L 26L 25M 26M 25H 26H 27L 28L 27H 28H
[0075] In one preferred embodiment, and referring to FIGS. 4 and 5,
the distance S1 is about 0.40 inches, the radii of curvature R4 are
about 0.12 inches, the angle .theta..sub.F is about 8.degree., R5
is about 5 inches, the distance S2 is about 0.39 inches, the marker
bump 58 has a radius of curvature of about 0.03 inches and a height
of about 0.015 inches, the location rib 66 has a radius of
curvature of about 0.19 inches and a height of about 0.06 inches,
and the radius of curvature at the peripheral edge of the lower
surface of the foot plate 20 is about 0.06 inches. The foot plate
20 may be otherwise dimensioned, as needed or desired.
[0076] Upper Ankle Plate
[0077] Referring to the drawings, and in particular to FIGS. 1-3
and 6-9, the upper ankle plate or member 22 is smaller in length
than the foot plate 20 and has average and major widths smaller
than the respective average and major widths of the foot plate 20.
The ankle plate 22 is preferably centered transversely with respect
to the foot plate 20. Preferably, the ankle plate 22 is generally
positioned over the back portion of the arch section 48 of the
lower foot plate 20 and substantially above the ankle block 24. The
ankle plate 22 preferably extends substantially more forward of the
attachment axis 34 (FIG. 1) than rearwardly. The contour of the
lower surface of the ankle plate generally conforms to the contour
of the upper surface of the ankle block 24.
[0078] In other preferred embodiments, the ankle plate 22 can be
shaped, sized, configured and/or positioned in alternate manners
with efficacy, as required or desired, giving due consideration to
the goals of providing a suitably strong and generally natural
feeling prosthetic foot 12, and/or of achieving one or more of the
advantages and benefits as taught or suggested herein.
[0079] The upper ankle plate 22 is preferably capable of flexing
along its length. Desirably, the flexing of the ankle plate 22
under the weight of the amputee tends to distribute and/or relieve
shear stresses applied at the interface between the ankle plate 22
and ankle block 24. Moreover, the flexing contributes to a more
natural feeling walking and/or running stride for the wearer of the
prosthetic foot 12.
[0080] In one preferred embodiment, the ankle plate 22 generally
comprises an anterior section or portion 76, a medial section or
portion 78 and a posterior section or portion 80. The front section
76 generally extends towards the toe region 46 of the lower foot
plate 20 and the rear section 80 generally extends towards the heel
region 50 of the lower foot plate 20. Preferably, the ankle plate
22 is generally sized, shaped and/or configured to approximately
simulate the dynamics of the upper portion of a natural human foot.
Optionally, the ankle plate 22 can comprise a generally flat plate,
as needed or desired.
[0081] Preferably, the ankle plate front section 76 is generally
inclined or noses in a downward direction relative to a plane
P.sub.3 (FIG. 8) which is substantially perpendicular to a plane
through the attachment axis 34. This nosing of the front section 76
generally simulates the structure of the upper portion of a natural
human foot. Moreover, the downwards inclination of the front
section 76 preferably generally follows the underlying contour of
the upper surface of the foot plate 20. Advantageously, this
results in a generally uniform thickness of the ankle block 24
material underneath the ankle plate front section 76. It has been
determined that such a shape and/or configuration causes improved
performance characteristics and longer durability with reduced
chances of delamination, peeling or separation between the ankle
block 24 and the plates 20, 22.
[0082] Moreover, the downwards inclination of the front section 76
permits clearance space between the ankle plate front section 76
and the surrounding cosmesis 14 which can allow longer layers of
the ankle block 24 to extend towards the foot plate toe region 46,
as needed or desired. In other preferred embodiments, the ankle
plate front section 76 can be shaped, sized and/or configured in
alternate manners with efficacy, as required or desired, giving due
consideration to the goals of providing improved performance
characteristics, and/or of achieving one or more of the advantages
and benefits as taught or suggested herein.
[0083] Preferably, the ankle plate front section 76 has a tapered
thickness with the smallest thickness substantially at or near a
front end 82 to allow more flexing of the ankle plate front section
76 near the front region of the ankle block 24. In other preferred
embodiments, the ankle plate front section 76 can be shaped, sized
and/or configured in alternate manners with efficacy, as required
or desired, giving due consideration to the goals of providing
improved performance characteristics, and/or of achieving one or
more of the advantages and benefits as taught or suggested
herein.
[0084] Preferably, the ankle plate front section 76 has a tapered
width with the smallest width substantially at or near a front end
82. This substantially conforms to the configuration of the
underlying ankle block 24 and also more closely simulates the
structure of the upper portion of a natural human foot. In other
preferred embodiments, the ankle plate front section 76 can be
shaped, sized and/or configured in alternate manners with efficacy,
as required or desired, giving due consideration to the goals of
providing improved performance characteristics, and/or of achieving
one or more of the advantages and benefits as taught or suggested
herein.
[0085] In one preferred embodiment, the lower surface of the ankle
plate front section 76 comprises a location rib or bump 86 for
establishing the relative positioning between the ankle plate 22
and the ankle block 24. The location bump 86 mates with or engages
a corresponding groove on the upper surface of the ankle block 24.
The rib 86 may also provide added protection against separation,
peeling or delamination between the ankle plate 22 and the ankle
block 24.
[0086] Alternatively, the location rib may be provided on the ankle
block 24 and the corresponding groove may be provided on the ankle
plate 22. Additionally, other positioning means such as location
pins and the like may be efficaciously used, as required or
desired, giving due consideration to the goals of establishing the
desired positioning between the ankle plate 22 and the ankle block
24, and/or of achieving one or more of the advantages and benefits
as taught or suggested herein.
[0087] Preferably, the location rib 86 extends crosswise across the
span of the lower surface of the ankle plate 22. In other preferred
embodiments, the rib 86 (and corresponding groove) can be
positioned and configured in alternate manners with efficacy, as
required or desired, giving due consideration to the goals of
establishing the desired positioning between the ankle plate 22 and
the ankle block 24, and/or of achieving one or more of the
advantages and benefits as taught or suggested herein.
[0088] The ankle plate medial section 78 is generally rectangular
in shape and has top and bottom surfaces which are generally
parallel to the plane P.sub.3 (FIG. 8). Preferably, the middle
section 78 is generally positioned above the flat upper surface 64
of the foot plate arch section 48. The width of the medial section
78 is generally about the same as the width of the foot plate 20
below it. In other preferred embodiments, the ankle plate medial
section 78 can be shaped, sized, configured and/or positioned in
alternate manners with efficacy, as required or desired, giving due
consideration to the goals of providing improved performance
characteristics, and/or of achieving one or more of the advantages
and benefits as taught or suggested herein.
[0089] The ankle plate middle section 78 includes a through cavity
or hole 88 extending between the lower and upper surfaces of the
middle section 78 to receive a bolt or screw 30 and a washer 32
(FIG. 1). The fastening bolt 30 is used to secure the attachment
member 28 (FIG. 1) to the ankle plate 22. The cavity 88 includes a
lower cavity or hole 90 and an upper cavity or hole 92. The lower
cavity 90 has a larger diameter compared to the diameter of the
upper cavity 92 to receive a head 94 (FIG. 1) of the bolt 30 and
the washer 32. The upper cavity 92 receives a shank or threaded
portion 96 (FIG. 1) of the bolt 30.
[0090] The attachment member 28 connects the prosthetic foot 12 to
a stump or lower leg pylon (not shown) of a wearer. The attachment
member 28 is adapted to be fastened to the upper surface of the
ankle plate middle section 78. Preferably, the upper surface of the
ankle plate middle section 78 has a pair of central lengthwise
grooves 98 (labeled 98a, 98b in FIGS. 6-8) which engage or mate
with corresponding protrusions on the lower surface of the
attachment member 28. Advantageously, this prevents or mitigates
undesirable relative rotation and/or displacement between the ankle
plate 22 and the attachment member 28.
[0091] Preferably, the grooves 98 are substantially V-shaped,
though other shapes can be employed with equivalent efficacy.
Alternatively, one or more grooves may be provided on the lower
surface of the attachment member 28 and the corresponding mating
protrusions on the upper surface of the ankle plate middle section
78, as required or desired, giving due consideration to the goals
of preventing or mitigating relative rotation and/or displacement
between the ankle plate 22 and the attachment member 28, and/or of
achieving one or more of the advantages and benefits as taught or
suggested herein.
[0092] In one preferred embodiment, the attachment member 28
comprises a male pyramid connector and includes a coupling knob 100
(FIG. 1) for mating with a coupling member on the pylon of the
wearer. In the illustrated embodiment, the attachment member or
pyramid connector 28 comprises a base plate 102 (FIG. 1), having
the upstanding coupling knob 100 formed integrally therewith. The
attachment member further may include a pair of upstanding location
pins which help transmit torsional forces between the pylon and the
foot prosthesis 12 and/or the prosthetic foot assembly 10.
[0093] A central threaded bore 104 (FIG. 1) in the knob 100
threadably receives the threaded portion or shank 96 of the
fastening bolt 30 extending upwardly through the aperture 88 in the
ankle plate middle section 78. Of course, other attachment members
can be attached via the upwardly directed fastening bolt 30, as
will be readily apparent to those of skill in the art. Moreover,
other fastening means such as pins, locks, clamps and the like may
be efficaciously used, as needed or desired.
[0094] Advantageously, the head 94 of the upwardly directed
fastening bolt 30 resides within the ankle plate 22 and the bolt 30
does not traverse the ankle block 24 or the foot plate 20. Thus,
bolt receiving cavities or holes are not needed in the ankle block
24 and the foot plate 20. This can be particularly important in the
case of the ankle block 24 since such cavities or holes formed
within the ankle block 24 may adversely affect the compressible or
resilient properties of the ankle block 24, and hence affect the
performance characteristics of the prosthetic foot 12. Optionally,
a downwardly directed bolt may be utilized so that the bolt head 94
is seated within the attachment member 28 and the threaded portion
or shank 96 is threadably engaged with the ankle plate 22.
[0095] The ankle plate rear section 80 is generally rectangular in
shape with generally curved side surfaces, and top and bottom
surfaces which are generally parallel to the plane P.sub.3 (FIG.
8). Preferably, the rear section 80 is generally positioned above
the flat upper surface 64 of the foot plate arch section 48 and may
also be positioned above part of the foot plate heel region 50. The
major width of the rear section 80 is generally less than the width
of the portions of the ankle block 24 and foot plate 20 below it.
The major width of the rear section 80 is also generally less the
width of the ankle plate medial section 78. In other preferred
embodiments, the ankle plate posterior section 80 can be shaped,
sized, configured and/or positioned in alternate manners with
efficacy, as required or desired, giving due consideration to the
goals of providing improved performance characteristics, and/or of
achieving one or more of the advantages and benefits as taught or
suggested herein.
[0096] Preferably, the limit strap or extension delimiter 26 (FIGS.
1-3) generally circumscribes portions of the ankle plate 22, ankle
block 24 and foot plate 20 at or near the rear or heel of the
prosthetic foot 12. The limit strap 26 is in contact with the upper
surface of the ankle plate posterior section 80 and the lower
surfaces of one or both of the foot plate arch section 48 and foot
plate heel section 50. The strap 26 preferably forms a generally
snug fit around the sandwiched assembly of the foot plate 20, ankle
plate 22 and ankle block 24 though there are gaps or clearance
spaces 106 between the strap 26 and the curved sides of the ankle
plate rear section 80, as seen in FIG. 3.
[0097] The limit strap 26 serves to contain or control the
separation to prevent delamination between the ankle block 24 and
the plates 20, 22 at or near the heel of the prosthetic foot 12
during the heel-off portion of the amputee's stride, when the rear
of the foot 12 undergoes maximum or high tension or stretching. The
limit strap 26 desirably has an overlap 108 (FIG. 2) which is sewn
using a cross-stitch of heavy thread. Although the strap 26 is
shown with the overlapped portion 108 above the top surface of the
ankle plate 22, it is understood that the overlap 108 may be
positioned otherwise.
[0098] Preferably, the ankle plate 22 is fabricated from a vinyl
ester based sheet molding compound, such as Quantum QC-8800,
available from Quantum Composites of Midland, Mich. The ankle plate
22 preferably comprises a vinyl ester resin matrix with a
substantially randomly arranged fiberglass fiber content. In
another preferred embodiment, the ankle plate 22 is constructed of
fiberglass. Alternatively, the ankle plate 22 may be formed by a
plurality of lamina embedded in a hardened flexible polymer. The
ankle plate 22 can also be formed of carbon fibers.
[0099] In other arrangements, the ankle plate 22 may be formed of
alternate suitable materials, such as other composite materials,
plastics, thermoplastic and thermosetting polymers, metals, alloys
and ceramics among others, as required or desired, giving due
consideration to the goals of achieving one or more of the
advantages and benefits as taught or suggested herein. The
desirable properties of the ankle plate 22 are that it is
relatively resilient so as to withstand cracking upon application
of repeated bending stresses, yet has sufficient flexibility to
enhance the performance characteristics felt by the wearer, in
conjunction with the properties of the resilient ankle block 24 and
the foot plate 20.
[0100] Preferably, the ankle plate 22 is formed by a molding
process. More preferably, the ankle plate 22 is formed by a
compression molding process. Alternatively, the ankle plate 22 can
be formed by an injection molding process. In other preferred
embodiments, the ankle plate 22 can be fabricated using other
techniques, for example, machining, welding, laminating, casting
and forging among others, with efficacy, as required or desired,
giving due consideration to the goals of providing enhanced
performance, and/or of achieving one or more of the advantages and
benefits as taught or suggested herein.
[0101] TABLE 3 below, in accordance with one preferred embodiment,
lists various approximate dimensions of the ankle plate 22 for
various amputee foot sizes. The number in the "SIZE" column in
TABLE 3 refers to the cosmesis size or overall length in
centimeters. The other column heading symbols in TABLE 3 refer to
dimensional labels as marked on FIGS. 7-8. A, B, D, F, K refer to
lengths (in inches), H, I refer to widths (in inches), and C, E
refer to thicknesses. It will be appreciated that other dimensions
than those of TABLE 3 may be used, as needed or desired.
4TABLE 3 ANKLE PLATE DIMENSIONS FOR DIFFERENT FOOT SIZES
(CORRESPONDS TO FIGS. 7 AND 8) SIZE A B C D E F H I K 21-22 2.55
1.53 .300 .61 .950 4.080 1.50 1.10 2.55 23-24 2.60 1.70 .300 .63
.960 4.300 1.64 1.20 2.60 25-26 2.68 1.80 .340 .67 .997 4.480 1.76
1.30 2.68 27-28 2.75 1.97 .340 .72 1.027 4.720 1.90 1.40 2.75
[0102] In one preferred embodiment, and referring to FIGS. 7 and 8,
the length G1 is about 0.85 inches, the length G2 is about 1.70
inches, the thickness G3 is about 0.35 inches, the thickness G4 is
about 0.12 inches, the length G5 is about 1.70 inches, the radius
of curvature R1 is about 0.22 inches, the radius of curvature R2 is
about 0.50 inches, the angle .theta..sub.A1 is about 5.degree., the
angle .theta..sub.A2 is about 170.degree., the angle .theta..sub.A3
is about 6.degree., the diameter of the cavity 92 is about 0.41
inches, the diameter of the cavity 90 is about 1.00 inches, the
location rib 86 has a radius of curvature of about 0.19 inches and
a height of about 0.06 inches, the grooves 98 have a depth of about
0.06 inches and a width of about 0.06 inches, the curved side
surfaces of the rear section 80 have a radius of curvature of about
0.25 inches. The ankle plate 22 may be otherwise dimensioned, as
needed or desired.
[0103] The bolt 30 is preferably a metric hex head bolt and
preferably comprises stainless steel. The bolt 30 is cold formed
with rolled threads and passivated. The minor diameter of the bolt
head 94 is about 16.85 mm. The head 94 is about 6.30 mm thick. The
shank 96 of the bolt 30 is about 30 mm long and comprises threads
(M10-1.5) along its whole length. Alternatively, a wide variety of
other bolts may be used with equivalent efficacy, as needed or
desired.
[0104] The washer 32 is preferably flat and round and is formed
from stainless steel. The washer 32 has a thickness of about 0.050
inches, an inner diameter of about 0.406 inches, and an outer
diameter of about 0.875 inches. Alternatively, a wide variety of
other washers may be used with equivalent efficacy, as needed or
desired.
[0105] The attachment member or pyramid connector 28 is preferably
formed from titanium or a titanium alloy such as TIMETAL 6S2,
6A1-4V titanium, or TI 3-1. The pyramid connector has a major
diameter of about 1.614 inches and a height of about 0.758 inches.
The central threaded bore 104 of the connector 28 preferably
comprises a M10-1.5 threaded through cavity. Alternatively, a wide
variety of other attachment members may be used with equivalent
efficacy, as needed or desired.
[0106] The limit strap 26 preferably comprises a thick natural
tubular nylon webbing or a woven nylon having a thickness of about
0.078 inches and a width of about 0.75 inches. The overlap 108 is
sewn with a box stitch overlap with "X", double back tack at both
ends. A bonded polyester thread (Dabond) is used to create the
overlap 108 with 8 stitches per inch. Alternatively, the overlap
108 can be stitched using a cross-stitch of heavy nylon thread.
After cutting a strap of appropriate length from the raw material,
the ends of the strap are melted.
[0107] For a foot size of 21-22, the strap 26 has an open (ends not
overlapped) span of about 6.70 inches, an overlap 108 of about 1.10
inches, and an internal diameter of about 1.65 inches. For a foot
size of 23-24, the strap 26 has an open (ends not overlapped) span
of about 7.20 inches, an overlap 108 of about 1.20 inches, and an
internal diameter of about 1.81 inches. For a foot size of 25-26,
the strap 26 has an open (ends not overlapped) span of about 7.70
inches, an overlap 108 of about 1.30 inches, and an internal
diameter of about 1.93 inches. For a foot size of 27-28, the strap
26 has an open (ends not overlapped) span of about 8.10 inches, an
overlap 108 of about 1.40 inches, and an internal diameter of about
2.02 inches. The strap 26 can be dimensioned in alternate ways, as
needed or required.
[0108] Compressible Ankle Block
[0109] Referring to the drawings, and in particular to FIGS. 1-3
and 10-12, the ankle block or cushion 24, is positioned
intermediate the foot plate 20 and the ankle plate 22 and
preferably comprises a monolithic element of material. Preferably,
and as discussed in greater detail below, the lower surface of the
ankle block 24 is bonded to the foot plate 20 and the upper surface
of the ankle block 24 is bonded to the ankle plate 22 using an
adhesive.
[0110] The ankle block or keel 24 is smaller in length than the
foot plate 20 and longer than the ankle plate 22. The average and
major widths of the ankle block 24 are smaller than the respective
average and major widths of the foot plate 20. The average width of
the ankle block 24 is slightly greater than the average width of
the ankle plate 22 while the major width of the ankle block 24 is
about the same as the major width of the ankle plate 22.
[0111] The ankle block 24 is preferably centered transversely with
respect to the foot plate 20 and the ankle plate 22. Preferably,
the ankle block 24 is generally positioned over the back portion of
the arch section 48 of the lower foot plate 20 and under the length
of the upper ankle plate 24. The ankle block 24 preferably extends
substantially more forward of the attachment axis 34 (FIG. 1) than
rearwardly. The contour of the lower surface of the ankle block 24
generally follows the contour of the portion of the upper surface
of the foot plate 20 on which it is seated. The contour of the
upper surface of the ankle block 24 generally follows the contour
of the lower surface of the ankle plate 22.
[0112] In other preferred embodiments, the ankle block 24 can be
shaped, sized, configured and/or positioned in alternate manners
with efficacy, as required or desired, giving due consideration to
the goals of providing a smooth and life-like response during
walking and/or running activities, and/or of achieving one or more
of the advantages and benefits as taught or suggested herein.
[0113] Advantageously, the ankle block 24 provides a cushioning
effect and expands (stretches in tension), contracts (compresses)
and/or distorts under the weight of the amputee during heel-strike,
flat footed, heel-off and toe-off stages of walking and running
activities. During walking and/or strides, the majority of the
compressive forces imparted by the wearer is absorbed by the ankle
block 24, with a small portion being absorbed by the flexible lower
foot plate 20 and flexible upper ankle plate 22 of the prosthetic
foot 12.
[0114] In one preferred embodiment, the ankle block 24 generally
comprises an anterior section or portion 116 and a posterior
section or portion 120. The front section 116 generally extends
towards the toe region 46 of the lower foot plate 20 and the rear
section 120 generally extends towards the heel region 50 of the
lower foot plate 20.
[0115] Preferably, an upper surface 122 of the ankle block front
section 116 is inclined in a downward direction relative to a plane
P.sub.4 (FIG. 12) which is substantially perpendicular to a plane
through the attachment axis 34. This downwards inclination of the
upper surface 122 of the ankle block front section 116 generally
corresponds to the downwards inclination of the lower surface of
the ankle plate front section 76 (FIG. 8) and has advantages and
benefits as discussed above. In other preferred embodiments, the
ankle block front section 116 can be shaped, sized and/or
configured in alternate manners with efficacy, as required or
desired, giving due consideration to the goals of providing a
smooth and life-like response during walking and/or running
activities, and/or of achieving one or more of the advantages and
benefits as taught or suggested herein.
[0116] Preferably, a lower surface 124 of the ankle block front
section 116 is curved to generally follow the curvature of the
portion of the foot plate arch section 48 below it. Desirably, this
results in a generally uniform thickness of the ankle block front
section 116. Functional testing has shown that such a shape and/or
configuration causes improved performance characteristics and
longer durability with reduced chances of delamination, peeling or
separation between the ankle block 24 and the plates 20, 22.
[0117] A downwardly sloping front end 126 of the ankle block 24
forms a face 128 connecting the upper and lower surfaces 122, 124
of the ankle block 24. The face 128 is inclined relative to the
vertical or to the attachment axis 34 and extends downwardly from
the ankle plate 22 to the foot plate 20. This particular shape of
the ankle block 24 desirably contributes to a more uniform
distribution and transfer of compression stress. The shorter length
of the ankle plate 22 and the sloping front face 128 of the ankle
block 24 tend to reduce shear stresses occurring near the front end
or tip 82 of the ankle plate 22 which could otherwise cause
undesirable delamination of the prosthetic foot 12.
[0118] Preferably, the ankle block front section 116 has a tapered
width with the smallest width substantially at or near a front end
126. This tapered width generally conforms to the width of the
overlying portion of the ankle plate 22. In other preferred
embodiments, the ankle block front section 116 can be shaped, sized
and/or configured in alternate manners with efficacy, as required
or desired, giving due consideration to the goals of providing a
smooth and life-like response during walking and/or running
activities, and/or of achieving one or more of the advantages and
benefits as taught or suggested herein.
[0119] Preferably, the upper surface 122 of the ankle block front
section 116 comprises a crosswise location or positioning groove or
notch 130 which mates with the location rib 86 of the ankle plate
22. As discussed above, the location groove 130 and the location
rib 86 establish the desired relative positioning between the ankle
plate 22 and the ankle block 24.
[0120] The ankle block rear section 120 has a top surface 132 and a
bottom surface 134 which are generally parallel to the plane
P.sub.4 (FIG. 12). Preferably, the upper surface 132 is longer than
the lower surface 134. The rear section 120 is generally positioned
above the flat upper surface 64 of the foot plate arch section 48
and may also be positioned above part of the foot plate heel region
50. The width of the rear section 120 is generally about the same
as the width of the foot plate 20 below it. In other preferred
embodiments, the ankle block rear section 120 can be shaped, sized,
configured and/or positioned in alternate manners with efficacy, as
required or desired, giving due consideration to the goals of
providing a smooth and life-like response during walking and/or
running activities, and/or of achieving one or more of the
advantages and benefits as taught or suggested herein.
[0121] Preferably, the lower surface 134 of the ankle block rear
section 120 comprises a crosswise location or positioning groove or
notch 140 which mates with the location rib 66 of the foot plate
20. As discussed above, the location groove 140 and the location
rib 66 establish the desired relative positioning between the foot
plate 20 and the ankle block 24.
[0122] A rear end 142 of the ankle block rear section 120 has a
face 144 substantially parallel to the vertical or to the
attachment axis 34. Preferably, a downwardly and inwardly sloping
rear/lower face 146 of the rear end 142 connects the end face 144
to the lower face 134. This tapered or inclined face 146 results in
a substantially wedged configuration below and above the inclined
face 146. Advantageously, and as discussed below, such a
configuration provides a high degree of "plantar flexion."
[0123] Preferably, the ankle block 24 is bonded to the foot plate
20 and ankle plate 22 using Loctite 4471 Instant Adhesive (Item#
44704) manufactured by Loctite, Inc. and as available from R. S.
Hughs Co. of Anaheim, Calif. The Loctite adhesive is a medium
viscosity, fast curing, single component Cyanoacrylate adhesive
which is formulated for difficult to bond substrates. Preferably,
before the use of the adhesive, the surfaces to be adhered are
cleansed of any oils, degreased, abraded and cleaned.
Alternatively, other suitable adhesives, glues, or adhering
materials and techniques can be used with equivalent efficacy.
[0124] A preferred material for the ankle block 24 is polyurethane
foam such as Purcell Cellular Vulkollan Polyurethane, as available
from Pleiger Plastics Company of Washington, Pa. Preferably, the
polyurethane foam is a NDI/Polyester based polyurethane foam and
has a high load capacity, is abrasion and tear resistant, and has a
high elasticity with low permanent deformation. Alternatively, the
ankle block 24 may comprise other suitable resilient materials such
as natural or synthetic rubber, plastics, honeycomb structures or
other materials.
[0125] Cellular foam, however, provides a desirable viscoelastic
springiness for a more natural feeling stride without the drawback
of limited compression associated with solid elastomeric materials.
Furthermore, the cellular nature of the ankle block 24 makes it
lighter than solid elastomers. Foam densities between about 150 and
1500 kg/m.sup.3 may be used to obtain the benefits of the invention
taught herein.
[0126] The ankle block 24 provides a relatively stiff, yet flexible
ankle region which may be customized for various wearers. Heavier
wearers may require a denser and/or thicker resilient material for
the ankle block 24, while lighter wearers may require a less dense
material or less thickness. More detailed material specifications
and dimensions are presented later herein.
[0127] Preferably, the ankle block 24 is machined out of larger
blocks or units of material which are formed by molding. The
machining preferably comprises a water jet processing and can be
performed by Pleiger Plastics Company of Washington, Pa.
Preferably, any "molded skin" which is formed at the tool-block
interface during the molding of the larger blocks or units and
remains on the ankle block 24 is skived or sheared off the ankle
block 24 while ensuring the correct dimensions.
[0128] The "molded skin" can cause non-uniformity in the resilient
and/or compressible characteristics of the ankle block 24.
Moreover, it may make the adhesion of the ankle block 24 to the
plates 20, 22 more difficult. In one preferred embodiment, molded
skin is not allowed on any of the surfaces of the ankle block 24.
In another preferred embodiment, molded skin is allowed on the side
surfaces of the ankle block 24 but not on the top and bottom
surfaces.
[0129] In an alternative preferred embodiment, the ankle block 24
is formed by an injection molding process to achieve the desired
shape, size and/or configuration. In other preferred embodiments,
other techniques can be efficaciously utilized, as required or
desired, giving due consideration to the goals of providing a
smooth and life-like response during walking and/or running
activities, and/or of achieving one or more of the advantages and
benefits as taught or suggested herein.
[0130] Preferably, the surfaces of the ankle block 24 exposed to
the atmosphere, that is, the side surfaces are treated or coated
with a sealant to prevent moisture absorption over time due to the
micro-cellular nature of the preferred material forming the ankle
block 24. The absorption of moisture over time can change and/or
cause unpredictability in the dynamic characteristics of the ankle
block 24.
[0131] Preferably, E-6000 MV Clear (Non-flammable) Sealant (Product
Code 371000130) manufactured by Eclectic Products, Inc. and as
available from Ellsworth Adhesive Systems of Tustin, Calif. is
applied to the exposed surfaces of the ankle block 24. This sealant
is preferably used in conjunction with a sealant thinner or solvent
containing tetrachlorodethylene (perchloroethylene) manufactured by
PPG Industries, Inc. and as available from Gallade Chemical, Inc.
of Santa Ana, Calif. In other preferred embodiments, alternate
sealants and/or thinners may be efficaciously used, as required or
desired, giving due consideration to the goals of preventing or
mitigating moisture absorption by the ankle block 24, and/or of
achieving one or more of the advantages and benefits as taught or
suggested herein.
[0132] TABLE 4 below, in accordance with one preferred embodiment,
lists various approximate dimensions of the ankle block 24 for
various amputee foot and weight sizes. The number and letter in the
"SIZE" column in TABLE 4 respectively refer to the cosmesis size or
overall length in centimeters and the weight group (L=Light,
M=Medium, H=Heavy) of the amputee. The "Manuf. ID" refers to the
part identification for blocks of Purcell Cellular Vulkollan
Polyurethane as available from Pleiger Plastics Company of
Washington, Pa. and from which the ankle block 24 is fabricated to
the required design. The other column heading symbols in TABLE 4
refer to dimensional labels as marked on FIGS. 11-12 and to the
weight of the ankle block 24. B, C, D, E, H, J refer to length
scales (in inches), A refers to a width (in inches), L refers to a
thickness (in inches), and M refers to a radius of curvature (in
inches). Note that the H dimension is tangent to the radius of
curvature of the surface 124 and/or extends upto the beginning of
the curvature of the surface 124. It will be appreciated that other
dimensions and material specifications than those of TABLE 4 may be
used, as needed or desired.
5TABLE 4 ANKLE BLOCK DIMENSIONS AND WEIGHTS FOR DIFFERENT AMPUTEE
SIZES (CORRESPONDS TO FIGS. 11 AND 12) Ankle Block Manuf. Weight
SIZE ID A B C D E H J L M (Grams) 21-22L 15-40 1.50 4.32 2.55 1.55
.60 2.58 2.33 .92 5.75 25-30 21-22H 15-45 1.50 4.32 2.55 1.55 .60
2.58 2.33 .92 5.75 31-36 23-24L 15-40 1.64 4.57 2.60 1.73 .64 2.59
2.34 1.00 7.00 32-37 23-24M 15-45 1.64 4.57 2.60 1.73 .64 2.59 2.34
1.00 7.00 38-42 23-24H 15-50 1.64 4.57 2.60 1.73 .64 2.59 2.34 1.00
7.00 43-49 25-26L 15-45 1.76 4.73 2.68 1.83 .70 2.75 2.50 1.00 8.75
41-46 25-26M 15-50 1.76 4.73 2.68 1.83 .70 2.75 2.50 1.00 8.75
47-52 25-26H 15-55 1.76 4.73 2.68 1.83 .70 2.75 2.50 1.00 8.75
53-59 27-28L 15-45 1.90 4.97 2.75 2.00 .75 2.75 2.50 1.00 9.50
48-53 27-28H 15-50 1.90 4.97 2.75 2.00 .75 2.75 2.50 1.00 9.50
54-60
[0133] In one preferred embodiment, and referring to FIGS. 11 and
12, the thickness Q1 is about 0.25 inches, the angle .theta..sub.B1
is about 5.degree., the angle .theta..sub.B2 is about 10.degree.,
the angle .theta..sub.B3 is about 15.degree., the angle
.theta..sub.B4 is about 60.degree., the location grooves 130, 140
have a radius of curvature of about 0.19 inches and a depth of
about 0.06 inches. The ankle plate 22 may be otherwise dimensioned,
as needed or desired. For instance, other angles .theta..sub.B3
ranging from about 5.degree. to about 45.degree. and other angles
.theta..sub.B4 ranging from about 45.degree. to about 75.degree.
may be used to achieve the benefits taught herein.
[0134] As indicated above, in one preferred embodiment, the ankle
blocks 24 are formed from larger blocks or block units of Purcell
Cellular Vulkollan Polyurethane as available from Pleiger Plastics
Company of Washington, Pa. One preferred block size has dimensions
of 55 (+3/-2) mm.times.250 (.+-.5) mm.times.500 (+10/-3) mm and is
referred to as Block A in the TABLE 5 below. Another optional block
size has dimensions of 55 (+3/-2) mm.times.250 (.+-.5) mm.times.750
(+10/-3) mm and is referred to as Block B in the TABLE 5 below.
[0135] TABLE 5 lists material and property specifications for
Purcell Cellular Vulkollan Polyurethane as available from Pleiger
Plastics Company of Washington, Pa.
6TABLE 5 MATERIAL SPECIFICATION FOR PURCELL CELLULAR VULKOLLAN
POLYURETHANE Weight Weight Tensile Manuf. Block A Block B Density
Strength Elongation Tear Rebound Hardness ID (grams) (grams)
(kg/m.sup.3) (N/mm.sup.2) (%) (kN/m) (%) Shore A 15-35 2179-2358
3269-3537 317-343 4.00 390 8 70 20-30 15-40 2509-2716 3764-4073
365-395 4.50 410 10 70 25-35 15-45 2839-3073 4259-4610 413-447 5.50
430 12 70 30-40 15-50 3169-3431 4754-5146 461-499 6.50 450 14 70
35-45 15-55 3499-3788 5249-5682 509-551 7.50 465 18 70 40-50 15-60
3829-4146 5744-6218 557-603 8.00 470 20 70 45-55
[0136] Prosthetic Foot Dynamics
[0137] The prosthetic foot 12 of the invention provides a
particularly smooth and life-like response during normal walking or
running activities. The uniquely configured ankle block 24
transmits the forces imparted thereon by the foot plate 20 and the
ankle plate 22 such that the rollover or migration of the
compressed region of the ankle block 24 is gradual and natural as
felt by the amputee, as energy is cyclically stored and released
the prosthetic foot 12.
[0138] During heel-strike, the weight of the amputee is initially
transmitted to the heel of the leading foot, and the compressive
stresses are absorbed by the rear region 120 of the ankle block 24
at or near the rear end 142. As the amputee continues through
his/her stride, the compression of the ankle block 24 travels
smoothly and continuously toward the front portion 116 or end 126
of the ankle block 24 during the flat-foot position and leading to
the heel-off position. In the toe-off position the ankle block 24
starts to resume its original (uncompressed) state as some of the
weight of the amputee is being transferred to the opposite foot,
which has now moved forward. The ankle block 24 resumes its
original shape as the amputee lifts his/her leading foot of the
ground or supporting surface. Advantageously, the dynamics of such
a stride give the foot a natural feel.
[0139] During heel-strike, the heel section 50 of the foot plate 20
bends to some degree and a slight amount of bending may occur at
the rear section 80 of the ankle plate 22. In the heel-off
position, the toe section 46 of the foot plate 20 bends to some
degree and the front section 76 of the ankle plate 22 may bend
slightly. In the toe-off position there is less bending if any of
both the foot plate toe section 46 and the ankle plate front
section 76.
[0140] It is important to note that although the ankle block 24
absorbs a majority of the compression generated by the wearer, the
flexible foot plate 20 and the flexible ankle plate 22 are designed
to work in conjunction with the resilient ankle block 24 and
provide enhanced dynamic performance.
[0141] Another advantage is provided by the high degree of "plantar
flexion" due to the wedged configuration of the rear end 142 of the
ankle block 24. Referring in particular to FIGS. 1, 5 and 12, this
wedged configuration or inward taper of the face 146 results in an
increased and/or predetermined distance between the foot plate heel
end 62 (and heel region 50) and a contact axis 150 formed at the
contact location between the taper 146 of the ankle block 24 and
the upper surface of the lower foot plate 20. Advantageously,
during heel-strike, this effectively results in a longer moment,
lever or cantilever arm between the heel end 62 (and heel region
50) and the effective fulcrum point or axis (which is at or close
to the contact axis 150). Desirably, this translates into more
downward deflection of the toe end 60 (and toe region 46) caused by
more upward deflection of the heel end 62 (and heel region 50) or
"plantar flexion."
[0142] At heel-strike, the flexible heel member 50 bends to absorb
the amputee's walking or running energy. This energy is
substantially uniformly transmitted to the flexible forefoot member
46, causing it to deflect downward before the toe makes contact
with the ground surface. Also, the subjection of the heel member or
region 50 to bending moments causes transmission of spring stress
through the heel region 50 to the forefoot or toe region 46 whereby
an energy return effect is achieved. This results in smoother
rollover and a better overall feel as the amputee's weight more
smoothly shifts forward from heel (heel-strike) to toe (heel-off).
Absent such deflection of the forefoot region 46, there is a
greater delay between heel-strike and toe strike (heel-off),
resulting in relatively unsmooth rollover.
[0143] Thus, the high degree of plantar flexion achieved by the
prosthetic foot 12 of the present invention adds to providing a
more smooth and life-like response during normal walking or running
activities. The wedged or taper feature of the ankle block 24 can
be adjusted or selectively dimensioned and configured, as required
or desired, giving due consideration to the goals of providing a
more natural walking and/or running feel and improved rebounding
and responsiveness, and/or of achieving one or more of the
advantages or benefits as taught or suggested herein.
[0144] Although not illustrated, the prosthetic foot 12 of the
present invention can also provide enhanced performance for the
wearer in inversion or eversion. The present invention allows the
amputee to walk transversely upon sloped surfaces, for example,
with the foot plate 20 generally conforming to the terrain while
the ankle plate 22 remains relatively horizontal due to the
sideways compression of the ankle block 24. Again, as the wearer
lifts his or her foot 12, the ankle block 24 resumes its original
shape, thus helping the wearer as energy is stored and then
released.
[0145] It can now be appreciated that the "feel" of the present
prosthetic foot 12 is greatly enhanced by the cooperation between
foot plate 20, ankle plate 22, and ankle block 24. As the wearer
continues through the walking stride, the dynamic response from the
prosthetic foot 12 is smooth as the ankle block 24 compresses in
different regions and a high degree of plantar flexion is achieved.
Further, the flexing of the foot plate 20 and ankle plate 22 also
assist in smoothly transmitting the various bumps and jars found in
uneven walking surfaces.
[0146] Outer Cosmesis
[0147] Referring to the drawings, and in particular to FIGS. 1-2
and 13-16, the flexible cosmesis 14 is an outer cover for a
prosthetic foot, such as the prosthetic foot 12, and is an
approximate replicate of the appearance of a human anatomical foot.
FIG. 13 shows an imaginary plane 36' which is upwardly offset from
the supporting ground surface 36 of FIG. 1 and is tangential to the
lower surface of the cosmesis 14 near the toe region. The
orientation of the cosmesis 14 with respect to the plane 36' is
indicative of a sole and/or heel of a shoe or other footwear worn
by the amputee over the cosmesis 14.
[0148] The cosmesis 14 is preferably fabricated from a flexible
material and provides an auxiliary or complementary cushioning
effect. The cosmesis 14 generally comprises an anterior or front
toe region 152, a posterior or rear heel region 154 and the inner
cavity 40 which includes an inner sole 156. The cavity 40 is
adapted to receive a prosthetic foot, such as the prosthetic foot
12. The sole 156 is shaped, sized and configured to conform to the
general shape, size and configuration of the lower foot plate
20.
[0149] Preferably, the cavity 40 further comprises a slotted region
158 at the toe portion 152 of the cosmesis 14 and a slotted region
or slot 160 at the heel portion 154 of the cosmesis 14. The slotted
region 158 is formed under an extending section 162 and is adapted
to receive the foot plate toe section 46. The slotted region 160 is
formed under an extending section or protrusion 164 and is adapted
to receive the foot plate heel section 50.
[0150] The toe region 152 of the cosmesis 14 comprises a big toe
166, an adjacent small toe 168 and three other small toes 170, 172,
174. In one preferred embodiment, the slit or slot 42 between the
big toe 166 and adjacent toe 168 is provided to receive a thong or
the like of a thong sandal or other footwear. Optionally, slits or
slots may also be provided between the small toes 168, 170, 172,
174, as needed or desired.
[0151] The cosmesis inner sole 156 comprises a pair of toe seating
portions 176, 178 at the toe region 152 of the cosmesis 14. The toe
seating portions 176, 178 are separated by an intermediate raised
portion 184 and the thong-receiving slot 42. The sole toe portion
176 is wider than the sole toe portion 178 and is configured to
seat one of the outer toes of the foot plate 20 and the central toe
of the foot plate 20, such as the outer toe 52a and the central toe
52c. The smaller sole toe portion 178 is configured to receive an
outer toe of the foot plate 20, such as the outer toe 52b. The
raised portion or member 184 is received in one of the slots 54
between the toes 52. Advantageously, because of the symmetric toe
configuration of the foot plate 20, as the skilled artisan will
recognize, the prosthetic foot 12 may be used with either a left or
a right foot cosmesis 14. Desirably, this adds to the versatility
of the invention.
[0152] The inner slotted region 158 comprises a pair of toe
receiving slots 180, 182 at the toe region 152 of the cosmesis 14.
The toe receiving slots 180, 182 are separated by an intermediate
raised portion 184 and the thong-receiving slot 42. The slot 180 is
wider than the slot 182 and is configured to receive one of the
outer toes of the foot plate 20 and the central toe of the foot
plate 20, such as the outer toe 52a and the central toe 52c. The
smaller slot 182 is configured to receive an outer toe of the foot
plate 20, such as the outer toe 52b. The raised portion or member
184 is received in one of the slots 54 between the toes 52.
Advantageously, because of the symmetric toe configuration of the
foot plate 20, as the skilled artisan will recognize, the
prosthetic foot 12 may be used with either a left or a right foot
cosmesis 14. Desirably, this adds to the versatility of the
invention.
[0153] The thong-receiving slot 42 of the cosmesis 14 can be
shaped, sized and/or configured in a wide variety of manners. In
one preferred embodiment, the slot 42 is substantially V-shaped. In
another preferred embodiment, the slot 42 is substantially
U-shaped. Other suitable shapes may also be utilized with
equivalent efficacy, as needed or desired.
[0154] The reinforcement patch or strap 44 is provided in the toe
region 152 of the cosmesis 14. The reinforcement patch 44 provides
a durable barrier between the foot plate 20 and the cosmesis 14 and
prevents or reduces wear of the sole 156 of the cosmesis 14 due to
frictional contact and/or compression stresses. The patch 44 may be
directly exposed to the foot plate toe region 46 and/or the foot
plate 20 and thus be part of the sole 156, or it may be covered by
a thin layer of the material forming the cosmesis 14 and hence be
slightly under the sole 156. Alternatively, some portion(s) of the
patch 44 may be directly exposed to the foot plate toe region 46
and/or the foot plate 20 and thus be part of the sole 156 and some
portion(s) may be covered by a thin layer of the material forming
the cosmesis 14 and hence be slightly under the sole 156. Some or
all of the edges of the patch 44 can be embedded in the material
forming the cosmesis 14.
[0155] The reinforcement patch 44 preferably comprises a first
supporting section or portion 190 and a wider second supporting
section or portion 192 with a slit or slot 194 formed therebetween.
The narrower first supporting section 190 is generally aligned with
the sole toe portion 178 and lies below or is generally aligned
with one outer foot plate toe 52. The wider second supporting
section 192 is generally aligned with the sole toe portion 176 and
lies below or is generally aligned with two adjacent foot plate
toes 52.
[0156] The patch slot 194 is substantially aligned with the
thong-receiving slot 42. The patch slot 194 is also aligned with
one of the slots 54 formed between the foot plate toes 52. The
patch slot 194 is further aligned with the raised portion 184
between the sole toe portions 176, 178.
[0157] The slot 194 of the reinforcement patch 44 can be shaped,
sized and/or configured in a wide variety of manners. In one
preferred embodiment, the slot 194 is substantially U-shaped. In
another preferred embodiment, the slot 42 is substantially
V-shaped. Other suitable shapes may also be utilized with
equivalent efficacy, as needed or desired.
[0158] The reinforcement patch 44 also includes a pair of spaced
registration holes 196 (labeled 196a, 196b) which assist in
positioning the patch 44 in the desired position during fabrication
of the cosmesis 14. More than two registration holes 196 may be
used, as needed or desired. Also, other registration means such as
registration pins may be used with equivalent efficacy.
[0159] Preferably, the foot plate 20 is bonded to the cosmesis
inner sole 156 (which may include exposed portions of the
reinforcement strap 44) using Loctite 4471 Instant Adhesive (Item#
44704) manufactured by Loctite, Inc. and as available from R. S.
Hughs Co. of Anaheim, Calif. The Loctite adhesive is a medium
viscosity, fast curing, single component Cyanoacrylate adhesive
which is formulated for difficult to bond substrates. Preferably,
before the use of the adhesive, the surfaces to be adhered are
cleansed of any oils, degreased, abraded and cleaned.
Alternatively, other suitable adhesives, glues, or adhering
materials and techniques can be used with equivalent efficacy.
[0160] The cosmesis 14 is preferably fabricated from a urethane
material such as urethane foam. Alternatively, the cosmesis 14 may
comprise other suitable resilient materials such as natural or
synthetic rubber, plastics, honeycomb structures or other
materials.
[0161] The cosmesis 14 is preferably formed using a molding process
such as injection molding or insert molding. The molding utilizes
an anatomically sculpted foot shape or mold, with details and
sizing based on a master pattern and/or digitized data representing
typical foot sizes. The molded density is approximately 25
lb/ft.sup.3, though in other embodiments it may be less or more, as
needed or desired.
[0162] A core part or tooling mandrel 198 (shown in phantom in FIG.
13) is preferably utilized during the fabrication/molding of the
cosmesis 14. After the molding process a predetermined length or
quantity of material 200 (FIG. 13) may be removed or cut off by
machining to finalize the sizing of the cosmesis.
[0163] The registration holes 196 of the reinforcement patch 44 are
engaged by a suitable tool or molding cone to orient and/or
position the patch 44 in the proper orientation and position during
the molding process. Desirably, the molding process also causes the
reinforcement patch 44 to be firmly bonded in place. As indicated
above, the surface of the patch 44 may be exposed, fully covered or
partially covered after the molding is completed.
[0164] The reinforcement strap 44 is preferably fabricated from a
polyurethane impregnated belting (Supplier Part No. FN1-12E) as
available from California Industrial Rubber Co. of Fresno, Calif.
This material generally comprises a urethane or polyurethane core
and a polyester casing, and has a tensile strength of 780 lb/in and
undergoes 1% elongation under a tensile force of 68 lb/in.
Alternatively, other suitably strong materials may be utilized, as
needed or desired. Preferably, the strap 44 is formed by stamping
and/or punching operations, though other techniques such as
machining among others can be used, as needed or desired.
[0165] TABLE 6 below, in accordance with one preferred embodiment,
lists various approximate dimensions of the cosmesis 14 (and other
related dimensions that may be used during molding of the cosmesis
14) for various amputee foot sizes. The number in the "SIZE" column
in TABLE 6 refers to the cosmesis size or overall length in
centimeters and the letter refers to the foot (L=Left, R=Right).
The other column heading symbols in TABLE 6 refer to dimensional
labels as marked on FIGS. 13 AND 16. All dimensions in TABLE 6 are
in inches. Note that the dimensions T1 to T11 are taken at
positions spaced by the corresponding value of Y, that is, the
position at which T1 is taken is spaced from the position where T2
is taken by Y, and so on. It will be appreciated that other
dimensions than those of TABLE 6 may be used, as needed or
desired.
7TABLE 6 COSMESIS DIMENSIONS FOR DIFFERENT FOOT SIZES (CORRESPONDS
TO FIGS. 13 AND 16) SIZE TH A Y T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11
21L .20 1.33 .79 .98 .85 .78 .73 .71 .63 .43 .29 .30 .33 -- 21R .20
1.33 .79 .98 .85 .78 .73 .71 .63 .43 .29 .30 .33 -- 22L .20 1.41
.79 .98 .85 .78 .73 .71 .63 .43 .29 .30 .33 .38 22R .20 1.41 .79
.98 .85 .78 .73 .71 .63 .43 .29 .30 .33 .38 23L .20 1.49 .86 1.04
.90 .82 .75 .75 .68 .51 .37 .32 .39 -- 23R .20 1.49 .86 1.04 .90
.82 .75 .75 .68 .51 .37 .32 .39 -- 24L .20 1.57 .86 1.04 .90 .82
.75 .75 .68 .51 .37 .32 .39 .44 24R .20 1.57 .86 1.04 .90 .82 .75
.75 .68 .51 .37 .32 .39 .44 25L .24 1.65 .93 .94 .83 .73 .69 .68
.58 .45 .34 .32 .40 -- 25R .24 1.65 .93 .94 .83 .73 .69 .68 .58 .45
.34 .32 .40 -- 26L .24 1.73 .93 .94 .83 .73 .69 .68 .58 .45 .34 .32
.40 .47 26R .24 1.73 .93 .94 .83 .73 .69 .68 .58 .45 .34 .32 .40
.47 27L .24 1.81 1.00 .90 .80 .72 .66 .62 .53 .36 .25 .25 .34 --
27R .24 1.81 1.00 .90 .80 .72 .66 .62 .53 .36 .25 .25 .34 -- 28L
.28 1.88 1.00 .90 .80 .72 .66 .62 .53 .36 .25 .25 .34 .40 28R .28
1.88 1.00 .90 .80 .72 .66 .62 .53 .36 .25 .25 .34 .40
[0166] In one preferred embodiment, and referring to FIG. 13, X1 is
about 0.40 inches, X2 is about 0.13 inches, X3 is about 0.40
inches, X4 is about 1.00 inches, X5 is about 0.375 inches, X6 is
about 0.75 inches, X7 is about 3.10 inches, X8 is about 2.00
inches, X9 is about 4.93 inches, and X10 is about 2.40 inches. The
cosmesis 14 and other length scales of FIG. 13 may be otherwise
dimensioned, as needed or desired.
[0167] For foot sizes 21-24, the reinforcement patch 44 has a
thickness of about 0.060 inches, a major length of about 1.96
inches and a major width of about 2.21 inches. The narrow section
190 has a width of about 0.49 inches and the wide section 192 has a
width of about 1.27 inches. The slot 194 has a length of about 1.37
inches and a width of about 0.45 inches. The registration holes 196
have a diameter of about 0.19 inches and are spaced by about 1.76
inches. The spacing between the holes 196 and the rear edge of the
patch 44 is about 0.26 inches. The spacing between the hole 196b
and the proximate side edge of the patch 44 is about 0.19 inches.
The spacing between the hole 196a and the proximate side edge of
the patch 44 is about 0.26 inches. In other embodiments, the patch
44 can be alternately dimensioned, as needed or desired.
[0168] For foot sizes 25-28, the reinforcement patch 44 has a
thickness of about 0.060 inches, a major length of about 1.96
inches and a major width of about 2.48 inches. The narrow section
190 has a width of about 0.63 inches and the wide section 192 has a
width of about 1.40 inches. The slot 194 has a length of about 1.37
inches and a width of about 0.45 inches. The registration holes 196
have a diameter of about 0.19 inches and are spaced by about 1.71
inches. The spacing between the holes 196 and the rear edge of the
patch 44 is about 0.35 inches. The spacing between the hole 196b
and the proximate side edge of the patch 44 is about 0.34 inches.
The spacing between the hole 196a and the proximate side edge of
the patch 44 is about 0.43 inches. In other embodiments, the patch
44 can be alternately dimensioned, as needed or desired.
[0169] While the components and techniques of the present invention
have been described with a certain degree of particularity, it is
manifest that many changes may be made in the specific designs,
constructions and methodology hereinabove described without
departing from the spirit and scope of this disclosure. It should
be understood that the invention is not limited to the embodiments
set forth herein for purposes of exemplification, but is to be
defined only by a fair reading of the appended claims, including
the full range of equivalency to which each element thereof is
entitled.
* * * * *