U.S. patent application number 11/693869 was filed with the patent office on 2007-07-19 for method for design and manufacture of insoles.
Invention is credited to Peter R. Cavanagh, Timothy B. Hurley, Jan S. Ulbrecht, Huixiong Zhang.
Application Number | 20070163147 11/693869 |
Document ID | / |
Family ID | 38261779 |
Filed Date | 2007-07-19 |
United States Patent
Application |
20070163147 |
Kind Code |
A1 |
Cavanagh; Peter R. ; et
al. |
July 19, 2007 |
Method for Design and Manufacture of Insoles
Abstract
A method for the design and production of improved pressure
reducing therapeutic shoe insoles for a person. The method includes
the steps of measuring a three dimensional image of a foot and the
distribution of plantar pressures applied by a person's foot being
measured for a pressure reducing insole. Selecting a shoe insole
outline or template which best fits or corresponds to the shape of
a foot being measured. A foot display is generated which combines
and aligns the three dimensional foot shape and the plantar
pressure distribution. A three dimensional insole display is
generated which combines and aligns the foot shape and plantar
pressure distribution, and includes modifications based upon
selected pressure contour lines identified within the foot display
which are above predetermined pressure thresholds.
Inventors: |
Cavanagh; Peter R.;
(Bratenahl, OH) ; Ulbrecht; Jan S.; (Boalsburg,
PA) ; Hurley; Timothy B.; (Boalsburg, PA) ;
Zhang; Huixiong; (State College, PA) |
Correspondence
Address: |
JEANNE E. LONGMUIR
2836 CORYDON ROAD
CLEVELAND HEIGHTS
OH
44118
US
|
Family ID: |
38261779 |
Appl. No.: |
11/693869 |
Filed: |
March 30, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11232204 |
Sep 21, 2005 |
7206718 |
|
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11693869 |
Mar 30, 2007 |
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Current U.S.
Class: |
36/44 |
Current CPC
Class: |
A61B 5/6807 20130101;
A43B 17/00 20130101; A43D 1/02 20130101; A61B 5/1036 20130101 |
Class at
Publication: |
036/044 |
International
Class: |
A43B 13/38 20060101
A43B013/38 |
Goverment Interests
GOVERNMENT INTEREST
[0002] This invention was supported under National Institutes of
Health grant no. R44 DK 59074-02 awarded by the National Institute
of Diabetes and Digestive and Kidney Diseases. The U.S. government
has certain rights in the invention.
Claims
1-15. (canceled)
16. A footwear insole for reducing plantar pressure which is
created based on the combination of a measured three dimensional
shape of an individual's foot and an individual's measured plantar
pressure distribution.
17. A footwear insole for reducing plantar pressure, said insole
having a base layer of material having an intervention formed
relative to a threshold pressure contour line identified by a shape
of a pre-measured plantar pressure distribution to be reduced.
18. The footwear insole of claim 17 wherein said threshold pressure
contour line is between 100 and 500 kPa.
19. The footwear insole of claim 17 wherein said intervention is a
relief and said relief includes a resilient, flexible layer of
elastomeric material.
20. The footwear insole of claim 17 further including a covering
layer of foam material having a thickness of approximately 5 mm or
less.
21. The footwear insole of claim 17 wherein the base layer is
ethylene vinyl acetate foam material and the covering layer is
polyurethane foam material.
22-24. (canceled)
25. The footwear insole of claim 17 wherein the intervention
includes an elevation at a location adjacent to an identified
region within the distribution of plantar pressures applied to the
footwear insole.
26. The footwear insole of claim 17 wherein the intervention
includes an elevation at a location distant from an identified
region within the distribution of plantar pressures applied to the
insole.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority from U.S. Patent
Application Ser. No. 60/611,775 filed Sep. 21, 2004, the entire
subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0003] 1. Field of Invention
[0004] The present invention relates to insoles for footwear and
more specifically to a method for computer aided design and
manufacture of custom pressure reducing insoles for footwear.
[0005] 2. Background of the Related Art
[0006] It is generally known that high plantar pressures under the
foot can lead directly to undesirable injury and symptoms in the
foot. Such injury or symptoms may include pain in a foot with
sensation, or tissue damage and ulceration in a foot without
sensation. As a result, reducing pressure at identified high
pressure locations is believed to offer a therapeutic strategy for
treatment of foot disorders.
[0007] In the past, insoles for footwear have been used to reduce
pressure at presumed or identified high pressure locations. Custom
and customized footwear insoles (where the term "custom" is used to
mean both fully custom and modified off the shelf footwear insoles)
are believed to provide improved pressure reduction over flat
insoles and this has indeed been demonstrated by recent research.
Manufacturing of such custom insoles is generally performed by
trained pedorthists/orthopaedic shoemakers, who customarily use a
negative mould of each foot for obtaining the desired base shape of
the insole, to which they then make primarily subjective
modifications to off-load the presumed or identified high pressure
locations. Due to its subjective nature, this process has been
shown to yield inconsistent results with respect to obtaining the
desired pressure reduction and, because the process is labor
intensive, it is expensive.
[0008] Computer aided manufacturing using numerically controlled
machines is also possible, as disclosed in U.S. Pat. Nos. 5,088,503
and 6,804,571. Such systems have provided some of the measurements
necessary to determine the high pressure locations to be
accommodated within the insole to be designed. However, such
systems have failed to provide the necessary combination of
measurements to accurately align the high pressure locations or
other locations of interest on the subject's foot with the insole
to be designed and manufactured, in order to obtain precise and
reproducible insoles from the measurements obtained. They have also
not provided an approach to determining pressure regions and
deciding the regions of interest based on a method of
"thresholding" these regions based upon measured plantar pressure
data. Such patented systems also suggest that footwear should
reduce pressure distributions toward some ideal value but research
has shown that the considerable variability in human feet makes
such a concept untenable. The improvements provided by the present
invention overcome these prior difficulties and result in an
improved method and system for producing an improved pressure
reducing insole.
SUMMARY OF THE INVENTION
[0009] The present invention provides an improved method and system
for designing and manufacturing an improved pressure reducing
insole for footwear of a person.
[0010] First, the three dimensional shape of the plantar surface of
the person's foot is measured and stored, resulting in digital data
in a three-dimensional reference frame. Such measurements may be
made for a person within the offices of a foot practitioner or from
an alternate location. A predetermined desired shoe insole template
is also selected. The external shape of the insole template is also
considered based upon the internal shape of the shoe in which the
insole is to be used. The appropriate insole template is selected
by comparing the two dimensional projection or foot shape from the
measured three dimensional shape of a foot with an insole template,
and selecting the template or outline data which best fits or
matches with the measured shape of the foot, which is then aligned
with respect to the template. The aligned three dimensional shape
and the aligned insole template are stored for later reference.
[0011] The foot contact forces or plantar pressure distribution
between the foot and the floor are also collected and stored during
barefoot walking by measuring the distribution of foot forces
applied by the person to a measuring arrangement. Foot pressures
measured inside the shoe between the foot and a flat or other base
insole could also be used. Again, such measurements may be made for
a person within the offices of a foot practitioner or from an
alternate location.
[0012] Once the necessary measurements are obtained, a combined
foot display is then generated and stored by aligning the base
insole, which is the measured shape of the foot appropriately
oriented with respect to the insole template, together with the
measured foot forces or plantar pressure distribution. Using this
combined foot display, specific target areas or regions on the
measured three dimensional shape of the foot (shown in two
dimensions) are identified which have pressures above a
predetermined pressure threshold of concern. Such pressure
thresholds may be in the range of 150 kPa to 450 kPa or lower or
higher, as may be selected. Additionally, such foot displays are
generated at a manufacturing facility to which the necessary
measurements have been communicated, either electronically or
otherwise.
[0013] Once such high pressure regions or other target areas are
identified and related to a location on the measured foot shape,
the stored data provided by the foot display is in a format
suitable to create modifications or customizations relative to the
measured three dimensional foot shape which reduce the foot
pressures where they are above the predetermined selected pressure
threshold values. The pressure contour lines corresponding to the
desired pressure threshold are used to form portions or all of the
shape of the pressure reducing insole modifications, which may be
either elevations or reliefs or both elevations and reliefs. The
shapes generated with respect to the threshold pressure contour
lines are stored as two dimensional polygons, and are combined with
the three dimensional measured shape of the foot and insole
template to generate a three dimensional insole display having the
location of the desired modifications based upon the shape of the
pressure threshold regions of the measured foot shape previously
identified. Using the three dimensional display, features of the
interventions may be specified, (such as intervention height or
depth (z-value) and leading edge slope) where such modifications
are based upon prior knowledge of pressure reductions typically
obtained upon making such modifications.
[0014] Once the three dimensional insole display is generated, it
is converted for use within the desired computer automated
manufacturing equipment, with which the physical insole template is
modified using the stored display data to create a pressure
reducing insole. Specifically, the insole is modified to enable
reduced plantar pressures in the target areas or regions
identified. The pressure reduction modifications incorporated into
the insole display may be obtained by creating reliefs or
depressions (also referred to herein as "interventions") in the
insole under the target area identified in the foot display.
Alternatively, or in addition, an elevation can be created in the
insole which is located adjacent to the target area identified.
Such elevations serve to transfer load away from the part of the
foot identified as being subject to elevated pressures. Regions of
the foot that are distant from the target area--such as the medial
longitudinal arch of the foot--may also be used for load transfer.
Alternately, different materials may be incorporated into the
insole template either immediately under the high pressure target
area or adjacent to it.
[0015] It should be understood that the system, method, processes
and procedures described herein could also be used for the
production of custom made shoes in which some of the modification
needed for pressure reduction are built into the mid-sole of the
shoe underneath the insole. Additionally, it should be understood
that modifications to the insole may be made which incorporate
practitioner input relating to unique factors which are not
otherwise accounted for in using the method outlined here.
[0016] These and other advantages and features of the invention
will be better understood from the detailed description of an
embodiment of the invention which is described in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic block diagram which provides an
overview flow chart of the present method and system for
manufacturing an improved custom pressure reducing insole;
[0018] FIG. 2 illustrates the use of a haptic lens technology
scanner for obtaining three dimensional foot data;
[0019] FIG. 3 schematically illustrates three dimensional foot data
gathered using haptic lens technology of the type disclosed in FIG.
2;
[0020] FIG. 4 schematically illustrates digitized three dimensional
foot data obtained from plaster casts of a person's foot;
[0021] FIG. 5 schematically illustrates a prior art commercially
available pressure platform system for collecting walking plantar
pressure distribution data from a person's foot;
[0022] FIG. 6 schematically illustrates a computer screen image of
EMED.RTM. data which shows a distribution of plantar pressure data
collected from a person's foot, where each of the foot shapes
includes discrete boxes containing the individually measured
plantar pressure values applied at the indicated location by the
person's foot to the pressure platform system as illustrated in
FIG. 5 during walking;
[0023] FIG. 7 schematically illustrates another representation of a
distribution of plantar pressure data collected from a person's
foot, where the foot shape includes discrete boxes, color-coded to
indicate various pressure values applied at the indicated locations
by a person's foot during walking, and pressure contour lines are
superimposed over the discrete boxes to better illustrate the
continuity of plantar pressures applied to the insole;
[0024] FIG. 8 illustrates a PEDAR.RTM. pressure insole for use in
the measurement of insole pressure within a shoe;
[0025] FIGS. 9 and 9A illustrate the foot shape data and insole
outline data as a computer program screen image before and after
alignment, respectively;
[0026] FIG. 10 illustrates a computer program screen image of the
aligned three dimensional foot shape data or base insole;
[0027] FIGS. 11 and 11A illustrate a computer program screen image
of the foot display with the aligned three dimensional foot shape
data, shown as a two dimensional view, and the measured plantar
pressure distribution data, before and after alignment,
respectively;
[0028] FIG. 12 illustrates a computer program screen image of the
highlighted threshold pressure contour lines within the three
dimensional foot shape data with measured plantar pressure
distribution data;
[0029] FIG. 13 schematically illustrates the relationship between
intervention feature position and intervention feature height on
pressure reduction under a metatarsal head;
[0030] FIG. 14 illustrates a computer program screen image of the
highlighted threshold pressure contour lines within the three
dimensional foot shape data with measured plantar pressure
distribution data, and with a selected portion of a contour line
highlighted which may form the leading edge of an insole
intervention;
[0031] FIG. 15 illustrates a computer program screen image of the
polygonal shaped intervention formed using the threshold pressure
contour line from the three dimensional foot shape data with
measured plantar pressure distribution data to form the leading
edge thereof;
[0032] FIG. 16 illustrates a computer program screen image of the
three dimensional insole display generated, together with a
smoothed shape of the intervention having the threshold pressure
contour line forming the leading edge;
[0033] FIG. 17 illustrates the blank insole template to be milled
to the modified insole within a computer controlled milling
machine;
[0034] FIG. 18 illustrates a final modified pressure reducing
insole manufactured in accordance with the methods, processes and
system of the present application; and
[0035] FIG. 19 illustrates the plantar pressure distributions
measured during validation comparison of the indicated barefoot
insole, OEM insole and the present improved pressure reducing
insole, graphically illustrates the reductions in plantar pressure
obtained using the improved insole of the present application.
DETAILED DESCRIPTION OF THE INVENTION
[0036] FIG. 1 provides a schematic block diagram of an overview of
the present method and system 20 for manufacturing an improved
custom pressure reducing insole 22 using a computer aided design
and manufacturing process. The method steps may be viewed as
several separate operations, such as a data input operation, which
may be performed at, or with the supervision of, a foot
practitioner's office, and an insole processing or manufacturing
process, which is performed within a manufacturing facility
operation.
[0037] Data Input--the initial step of the present method is to
collect relevant data from the person being measured for the
pressure reducing insole. The measured data collected is a three
dimensional scan of the foot 24 to assess three dimensional shape
and obtain digital data in a three-dimensional reference frame. The
three dimensional shape measured provides a baseline three
dimensional shape for the insole. A barefoot pressure measurement
26 is also obtained, or may be provided by the measurement of
in-shoe pressure during walking in a flat or neutral insole 28.
Foot practitioner input may also be provided to supplement
information regarding the person being measured. Additional data
such as toe height measurement may also be obtained. Where such
data is collected at a foot practioner's office, the data may be
transmitted to the manufacturing facility via the internet and well
known communication software as electronic data files. These data
inputs are further described as follows:
[0038] Foot scans and profiles. Appropriate shoe selection and
sizing is an important consideration in the treatment of various
foot-related conditions. Three-dimensional scanned images are used
to measure the overall shape of a person's feet, as well as to
obtain important two dimensional measurements such as an outline,
length and width. Obtaining such foot geometry establishes a
baseline insole for the person to which all subsequent
modifications are applied. Haptic lens technology HL of the type
disclosed in U.S. Pat. No. 5,459,329 and illustrated in FIGS. 2 and
3 may be used to collect and store such three dimensional data 24.
Alternatively, plaster casts of a person's foot may be taken and
digitized. Sample digitized data PD from a plaster cast is shown in
FIG. 4. Additionally, other optical and contact digitizers are
imaging techniques which may be employed to capture two and
three-dimensional foot shape and profile.
[0039] Barefoot plantar pressure distributions. Plantar pressure
distribution data 26 is collected using a pressure-measurement
platform 30 which measures the barefoot pressure 26 of the person.
As shown in FIG. 5, an EMED.RTM. system of the type available from
Novel, GmbH of Munich, Germany may be used to obtain two
dimensional plantar pressure distribution data 26 from a person
being measured. The EMED system includes software which converts
the measured data into a usable format thereby allowing for
assessment of the plantar pressure data profile, as shown in FIG.
6. As shown, FIG. 6 illustrates a user interface screen showing
measured foot images having individual boxes 32 indicating the
pressure applied by the foot at each associated location during
walking. FIG. 7 illustrates an alternative display of measured
plantar pressure distribution which also includes pressure contour
lines 34, which are overlaid on digitized three dimensional foot
shape data 26. Colors (not shown in either FIG. 6 or 7), but
commonly available with such software displays, are generally
included in such images to more readily distinguish variations
within the measured pressure data 26. Alternatively, barefoot
plantar pressure 26 can be measured inside the shoe while the
subjects walk in a conventional flat or base insole 28 having
sensors for monitoring and collecting pressure data, and
illustrated with a Novel PEDAR.RTM. insole measurement system in
FIG. 8.
[0040] Foot practitioner input. The practitioner has an opportunity
to provide input to the process by way of answers to questions
describing the person's physical characteristics, limitations and
personal lifestyle, and may impact insole design.
[0041] Toe height measurement. Sufficient shoe toe-box volume is
important, particularly for people who suffer from foot
deformities. Ample room in the toe-box will help to reduce the
formation of new problems caused by contact of the shoe upper with
the dorsum of the foot resulting from the use of an insole, which
reduces overall toe-box volume. Any measurement of the height of
anatomical features above the ground plane can be used for this
purpose, and may impact the height or other features of the insole
design.
[0042] Insole Template Selection. An insole outline 36 with an
external shape which best corresponds to the shape of the foot F
being measured, and which is appropriate for use within the
footwear S to be worn by the person being measured, is also
selected. Such insole outline data 36 may be selected from an
electronic library of available templates or files which represent
the outline or external shape of the insole to be created. The
insole outline data 36 chosen from such stored data sets generally
relates the measured foot length and width to a shoe/insole size.
The selection of insole outline data may require assistance from
the foot practitioner.
[0043] Insole Processing--Using the data collected from the steps
above, which is communicated to an insole manufacturing facility as
electronic data files, the custom insoles 22 are further designed
and produced via the application of an integrated computer aided
design--computer automated manufacturing (CAD-CAM) process. In the
preferred embodiment, the present system and method makes use of
the MATLAB.RTM. software program and associated tool sets,
available from The Math Works, Inc. of Natick, Mass. at
www.mathworks.com. The steps involved in this process are further
detailed in FIG. 1.
[0044] Insole outline alignment with the foot shape. As shown in
FIG. 9, the insole outline 36 or template previously selected is
provided as an input to the computer design program. Additionally,
the three dimensional foot shape data 24 is also provided. Both of
these collected data files are illustrated in the computer program
screen image of FIG. 9, but it is noted that the three dimensional
foot shape data 24 is shown and used as a two dimensional image in
this alignment step. Also, the foot shape data 24 in the toe region
of the measured foot has been removed from the data set, such that
the insole to be created addresses only modifications within the
illustrated area of the foot shape. Once the data files are opened,
the computer design program may be used to align the two
dimensional foot shape image within the insole outline. The insole
outline 36 is adjusted to a "best-fit" position with respect to the
scanned foot image 24 by a series of translations and rotations (x,
y and z axis adjustments are possible) based upon user input, as
shown in FIG. 9A. Because the width of the foot is generally
constrained inside a shoe to a value less than the barefoot width,
it may be necessary to scale the foot shape and pressure data to
allow appropriate fit within the insole outline 36. This can easily
be done mathematically as a step in processing the shape and
pressure distribution data, but small manual adjustments will
always be necessary. The output data files generated from this
alignment step for later processing include the three dimensional
foot shape aligned within the specific reference frame of the
insole outline (or having specific x, y, z coordinates), for
example, as shown in FIG. 10 and also referred to as the "base
insole" 40, and an insole outline also aligned with respect to the
specific reference frame 42.
[0045] Superposition and thresholding of plantar pressure. The
process of aligning the plantar pressure 26 on the base insole 40
is similar to the process of aligning the insole outline 36 as
previously described. The measured barefoot plantar pressure data
26, expressed for each sensor of the pressure measurement device
30, are provided and displayed as a new two-dimensional foot image
44, shown in operator selected pressure contour lines 34 having the
shape of a foot in FIG. 11. This pressure distribution 26 is
adjusted to a `best-fit` position over the aligned three
dimensional base insole 40 (shown in FIG. 11 as a two dimensional
image) by a series of translations and rotations (x, y and z axis
adjustments are possible) based upon user input. Features in the
pressure distribution such as toe pressures and the center of the
heel distribution are useful for this purpose. An automatic
algorithm can be implemented for this purpose, but small manual
adjustments will always be necessary. Once the plantar pressure
distribution 26 is aligned with the three dimensional foot shape
data 24, this aligned data or "foot display" 46 is stored as shown
in FIG. 11A.
[0046] Once the positioning is finished, individual measured
pressure values are compared to a threshold pressure value, which
is established by the user/operator, and a region of pressure
distribution is identified and highlighted within the computer
program as shown in FIG. 12 at 48. In the illustration of FIG. 12
the highlighted pressure contour lines 48 selected are 210 kPa,
such that pressure sensor values that exceeded the threshold
pressure value may be located within or outside the highlighted
contour line 48. In the preferred pressure reducing insole 22
embodiment of the present application, the identified threshold
pressure regions are used to form the shape of the insole
modifications or interventions to be made. In the preferred
embodiment, threshold pressures of approximately 200 kPa, when
measured using a sensor array with resolution of approximately 2-8
sensors per cm.sup.2, are believed effective for the location and
geometry of modifications or interventions to be made to the
improved pressure reducing insole 22 of the present application. As
used herein, the term interventions or modifications may include
either elevations or reliefs, including depressions and openings,
or combinations of both elevations and reliefs.
[0047] Intervention Feature Geometry and Position. Insole
modification features are specified based on rules derived from the
results of empirical studies on human subjects or the results of
finite element modeling studies. An example of the former is the
relationship between the location and magnitude of peak pressure at
a prominent metatarsal head and the location and height of a
pressure relieving feature placed posterior to this region. Such a
relationship is shown schematically in FIG. 13. Depending on the
required pressure relief, the choice of feature characteristics can
be made algorithmically. Features may include various surface
elevations and/or depressions and/or variations in the material
used, each aimed at transferring load away from high pressure areas
to lower pressure regions of the plantar surface.
[0048] In the illustrated embodiment, an intervention such as an
elevation is formed using the threshold pressure contour line 48
previously highlighted in FIG. 12. Once the desired threshold
pressure contour lines are identified, the desired region meeting
this threshold is selected for creation of a modification. In the
FIG. 12 illustration, for example, the highlighted bilobal shaped
pressure region generally under the metatarsal head of the foot
could be selected using the computer program. Once selected, the
specific portion 49 of the highlighted threshold pressure contour
line 48 which will form at least a portion of the shape of the
modification or intervention may also be selected. As shown in FIG.
14, a posterior edge portion 49, indicated by a dashed line, on the
threshold pressure contour line 48 has been selected to form the
leading edge 52 of an elevation intervention 50. To the extent the
selected threshold pressure contour lines 34 are disconnected but
adjacent, connections between the adjacent lines are selected to
form the highlighted region. The computer program may also be used
to manually remove any end or beginning points of the contour line,
so that the desired shape of the leading edge 52 for the
intervention 50 is obtained. It is noted that in the anterior
insole direction from the leading edge, the foot data 24 is
featureless in the illustrated embodiment. The nature of the
featureless line created ahead of the leading edge 52 may require
blending of the data so the intervention being created blends with
the three dimensional base insole 40. Such blending may be
accomplished by performing a one dimensional interpolation in the x
axis direction.
[0049] The one dimensional shape of the intervention 50 may then be
completed as desired and saved as a data file. In the illustrated
embodiment, the tail point or rear edge 54 of the shape of the
intervention 50 is selected at a location which is generally one
third of the overall length of the foot, or approximately 8-10 cm
for a base insole of 25-35 cm, and straight side edges 56 are
formed from the end points 58 of the leading edge contour line 49
to the tail point 54 selected, resulting in a polygon as
illustrated in FIG. 15.
[0050] Once the desired intervention 50 shape is obtained, the
shape is saved as a data file. Additional elevations or reliefs 50
may also be created for inclusion within the insole 22. For
example, a relief or depression having a shape of the region of the
threshold pressure contour 48 identified at 300 kPa, as illustrated
by the polygon R in FIG. 15, could also be selected and saved as a
data file.
[0051] The interventions 50 are then incorporated with the aligned
base insole 40 and the aligned outline or template 42 into a three
dimensional insole display 62 shown in FIG. 16. As shown in FIG. 1,
the aligned outline or template, aligned three dimensional foot
shape data 40 or base insole, and the intervention polygon files 60
created, if any, are selected within the computer program for
incorporation into an insole display 62. The height of the
intervention and distance back (and thus, slope) from the leading
edge 52 of the intervention 50 are also selected. In the preferred
and illustrated embodiment, a height H of approximately 12.5 mm
above a base B, which is approximately 5-6 mm, is believed to
provide desired pressure reductions during use of the insole. A
slope from the leading edge of the intervention toward the tail
point edge 54 is preferably within the range of 30 to 60 degrees,
and more preferably approximately 45 degrees, to obtain desired
pressure reductions during use of the insole 22. Once the
dimensional features of the intervention 50 are defined, various
methods may be employed to combine the intervention with the three
dimensional surface of the base insole 40. With these
characteristics and dimensions, the intervention 50 effectively
blends into the three dimensional foot shape 24. To ensure a
uniform surface along the edges of the intervention 50 with a
border 64 of the base insole 40, additional blending may be
required. Such blending may be determined based upon the shape of
the area between the intervention edges 56 and the border, and
values such as either the maximum or median values of the edge 56
or the border 64 data may be used to obtain the desired blended
surface 66 result.
[0052] It will be understood by one of ordinary skill in the art
that the creation of additional elevations may proceed using these
same procedures. Likewise, the creation of reliefs is generally
formed by selection of an entire threshold pressure contour line
48, or a full circular shape, for example, under the metatarsal
head region in the illustration of FIG. 14. The depth of such a
relief or depression is preferably in the range of approximately 1
to 3 mm from the base B of the base insole 40.
[0053] Smoothing algorithms, such as low and high pass filters, may
be selected to clean rough edges of the insole display 62. For
example, where data points in the heel cup section are
inconsistent, filling may be required to bring all data points to
the highest existing data point. Additional smoothing algorithms to
blend the shape of the intervention with the three dimensional foot
shape may also be required as discussed above. After final data
adjustments are complete, the modified insole surface is smoothed
and regenerated. The final smoothing of the entire insole surface
data is done, for example, using the spline tool feature within the
MATLAB computer program. The modified insole data is then saved to
enable recreation of the identical insole for a person at a later
time.
[0054] The final insole 22 is then created within MATLAB as shown
in FIG. 1 by combining the data indicated, which is then displayed
as an insole. If the insole display 62 requires further revisions,
additional changes may be made. Once a final insole display 62 is
satisfactory, the computer design program converts the mat two
dimensional data files and other three dimensional foot shape data
files into a stereolithography file (.stl), which is of the type
which generates a tool path in the convention appropriate for a
specific computer controlled milling or CNC machine in machine
readable numeric code to create the actual physical insole.
[0055] Milling the insole. The tool path file is transferred to a
computer controlled machine M as shown in FIG. 17. The milling
machine M directs the fabrication of the pressure reducing insole
starting from a blank stock 72 of a suitable foam material,
preferably ethylene vinyl acetate having an initial thickness of 1
to 2 inches, and a Shore A hardness within a range of 15-60, more
preferably 35-45, and more specifically approximately 40, such as
Cloud EVA Foam supplied by PEL Supply Company of Cleveland,
Ohio.
[0056] The finished insole. As shown in FIG. 18, the custom milled
insole 22 produced is hand finished, which may include fine
grinding and lamination of a top cushioning layer 70. The
cushioning layer 70 is preferably of a 5 mm or less thickness, and
of a polyurethane foam, which may include a fabric lining, having a
Shore A hardness within a range of 5-55, and more preferably
approximately 15, such as Poron.RTM. performance medical grade
manufactured by Rogers Corp. Prior to application of a top
cushioning layer, it may be desired to add a resilient, flexible
elastomeric material within any reliefs, in order to provide
additional cushioning between the foot and the footwear. Such
elastomeric material 74, shown in phantom under the top cushioning
layer in FIG. 18, may be a silicone gel material, such as G.E. RTV
6136 silicone gel, of the type available from G.E. Plastics. The
volume of gel required for the relief may be simply calculated by
creating and counting a 1.times.1 mm grid size formed from the
polygonal shape of the relief which is approximately 3 mm deep. A
solvent based adhesive, such as Duall-88, is preferably used to
secure components of the finished insole together. The finished
insoles 22 are assembled and sent to the foot practitioner or other
footwear provider for fitting to the person.
[0057] FIG. 19 graphically illustrates the plantar pressure
distributions 26 measured during validation comparison testing for
each of the indicated barefoot insole, OEM insole and the improved
pressure reducing insole of the present application, where the
graphic data in the shape of a foot pressure is thickest where the
pressures are highest. Obviously, the improved insole 22 of this
application created a reduced pressure condition over the barefoot
and original equipment manufacturers (OEM) insole scenarios.
[0058] While the present improved methods, processes, system and
insole have been described herein in connection with one or more
embodiments, it is understood that it should not be limited in any
way, shape or form to any specific embodiment but rather
constructed in broad scope and breadth in accordance with the
recitation of the following claims.
* * * * *
References