Patent Document

[0001]    This application is a Continuation-in-part application of U.S. application Ser. No. 09/692,015, filed on Oct. 18, 2000, the disclosure of which is incorporated in its entirety herein by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to an apparatus for measuring the geometry of a person&#39;s plantar contour and a method of forming a custom insole corresponding to the measured plantar contour. More particularly, the present invention relates to an impression block for taking a partial measurement of the plantar contour that can be extrapolated to produce a custom insole.  
           [0004]    2. Description of the Related Art  
           [0005]    A number of methods currently exist to measure the geometry of the plantar contour of a foot. The accurate measurement of the plantar contour is used in the manufacture of custom insoles. The prior art methods include plaster casting, optical scanning, contact sensor measurement, as well as impression measurement. These methods prefer the foot to be in a neutral position. However, some shoes, such as high heels or other shoes with a slope, distort the plantar contour and instep due to the shifting of the user&#39;s body weight. Accordingly, the insoles made using these prior art methods do not account for such distortions. Moreover, these prior art methods are not well suited for home use.  
           [0006]    The optical scanning methods and contact sensor measurement methods utilize expensive equipment. These methods provide an accurate and complete measurement of the foot. But, the size, expense and complexity of the equipment necessary for these methods makes them not suitable for use in all locations. Moreover, these methods do not permit accurate measurement of the geometry of the foot in the position it will be in when inside of a shoe.  
           [0007]    Plaster casting methods require the measurement to be performed by a person other then the one being measured. This method provides an accurate and complete measurement of the foot but can be very messy and time consuming. Thus, plaster casting methods are not suitable for use in a person&#39;s home or by one&#39;s self. Moreover, these methods do not permit accurate measurement of the geometry of the foot in the position it will be in when inside of a shoe.  
           [0008]    Impression measurement methods and apparatus utilize an easily deformable block. A person steps onto the block, thus crushing the block in the locations of higher pressure. In this manner, the block deforms in the approximate shape of the persons&#39; plantar contour. While this prior art method may be suitable for home use, it produces a sub-optimal characterization of the foot for a number of reasons. First, the block is uniform in thickness from heel to toe. This causes the toes to be forced upward as the foot is pressed into the block because the toes of the foot have substantially less pressure on them than the region of the foot from the heel to the metatarsal heads. Forcing the toes upward can cause a number of problems including, hyperextension of the plantar fascia, lowering of the correct arch height, and improper measurement of the forefoot and heel. Second, under full body weight, the foot expands allowing for a larger than normal foot impression. Additionally, the prior art does not provide for measurement of the instep. Moreover, the current materials and methods do not permit accurate measurement of the geometry of the foot in the position it will be in when inside of a shoe.  
           [0009]    In the manufacture of custom insoles, the use of the plaster casting and impression methods also require the use of a scanning system. The scanning system may act directly on the negative impression within the block or plaster. Scanning systems that act directly on negative impressions are known in the art. These laser-scanning systems consist of a laser with a line generating optic. The laser projects a line at a known incident angle onto the negative impression. A camera is used to read the position of the laser line on the negative impression. Alternatively, the scanning system may act upon a positive model using a casting medium such as plaster, wax or equivalent made form a negative impression contained in the foam block. One such scanning system, provided by U.S. Pat. No. 4,876,758, specially constructed array of pin-like sensors. In either circumstance, the scanning system is used to digitize the measured contour. The digitized contour is provided to a computer controlled milling machine. The milling machine uses the digitized information to manufacture a custom insole matching the digitized contour. Accordingly, the apparatus and methods of the present invention provide for cheaper, improved and easier means to provide custom manufactured insoles to a customer.  
           [0010]    Previously, the prior art impression block is required to measure the entire plantar contour in order for the scanning system to create a digitize contour sufficient to manufacture the custom insole. More specifically, the prior art impression block requires a thickness equal to or greater than the thickness of the blank used to manufacture the custom insole. However, impression blocks of such thickness have many drawbacks, such as large shelf space requirements, increased packaging costs, and increased shipping costs. In the instance where the prior art impression block is directed for use at home by the user and then to be shipped to a location for manufacture of the insole, such thick prior art devices are simply not practical.  
           [0011]    Accordingly, the present invention provides foot measurement apparatus and methods, which overcome the limitations set forth above.  
         SUMMARY OF THE INVENTION  
         [0012]    The present invention provides an apparatus for measuring a plantar contour of a foot of a user. The apparatus comprises a carrier and an impression block in the carrier. The impression block has a guide formed therein to aid the user in aligning the foot with respect to the impression block.  
           [0013]    The present invention also provides an apparatus for measuring a plantar contour of a foot of a user where the plantar contour having a height. The apparatus comprises an impression block having a thickness sufficient to form an impression of at least a portion of the height of the plantar contour.  
           [0014]    Additionally, the present invention provides a method for forming a complete digitized model of the height of a plantar contour of a foot of a user, wherein the plantar contour has a height. The method comprises the steps of: (1) placing the foot of the user into an impression block having a thickness, wherein the thickness is sufficient to form an impression of at least a portion of the height of the plantar contour; (2) forming a digitized model of the impression; (3) extrapolating data from the digitized model of the impression to form the complete digitized model of the full height of the plantar contour; and (4) forming a digitized model of the portion of the plantar contour; and (5) fabricating an insole from the portion of the digitized contour.  
           [0015]    An additional embodiment according to the present invention comprising an apparatus for measuring a plantar contour of a foot of a user having at least a portion of a shoe and an impression block disposed within the shoe, wherein the impression block has a guide formed therein to aid the user in aligning the foot with respect to the impression block. Preferably, the impression block include a first layer and a second layer, wherein the first layer is of lesser density than the second layer. Alternatively, the impression block is contained within a compliant medium, such as a plastic wrap to protect the impression from moisture and from sticking to the user&#39;s foot.  
           [0016]    Still an additional embodiment includes a method for forming a complete digitized model of the height of a plantar contour of a foot of a user, wherein the plantar contour has a height. The method comprises: placing the foot of the user into an impression block having a thickness and wherein a compliant medium is disposed between the impression block and the foot, wherein the thickness is sufficient to form an impression of at least a portion of the height of the plantar contour; filling the impression with a material which is capable of making a mold of the impression; forming a digitized model of the mold; and extrapolating data from the digitized model of the mold to form either a complete or partial digitized model of the full or partial height of the plantar contour, respectively. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is a rear perspective view of the impression block of the present invention.  
         [0018]    [0018]FIG. 2 is a rear perspective view of an embodiment of the container of the present invention.  
         [0019]    [0019]FIG. 3 is a side perspective view of an embodiment of the guide of the present invention.  
         [0020]    [0020]FIG. 4 is a rear perspective view of the impression block of FIG. 1 taking an impression.  
         [0021]    [0021]FIG. 5 is a rear perspective view of the impression block of FIG. 1 after taking an impression.  
         [0022]    [0022]FIG. 6 is a sectional view of the impression block of FIG. 5 taken along lines  6 - 6 .  
         [0023]    [0023]FIG. 6 a  is a comparison of the impression block of FIG. 6 and the insole blank.  
         [0024]    [0024]FIG. 7 is a sectional view of the impression block of FIG. 5 taken along lines  7 - 7 .  
         [0025]    [0025]FIG. 7 a  is a comparison of the impression block of FIG. 7 and the insole blank.  
         [0026]    [0026]FIG. 8 is a sectional view of the impression block of FIG. 5 taken along lines  8 - 8 .  
         [0027]    [0027]FIG. 8 a  is a comparison of the impression block of FIG. 8 and the insole blank.  
         [0028]    [0028]FIG. 9 a  is a top view of a die cut blank for a custom insole.  
         [0029]    [0029]FIG. 9 b  is a side view of the die cut blank of FIG. 9 a.    
         [0030]    [0030]FIG. 10 is a cross section of the die cut blank of FIG. 9 a  taken along lines  10 - 10 .  
         [0031]    [0031]FIG. 11 is a cross section of the die cut blank of FIG. 9 a  taken along lines  11 - 11 .  
         [0032]    [0032]FIG. 12 is a cross section of the die cut blank of FIG. 9 a  taken along lines  12 - 12 .  
         [0033]    [0033]FIG. 13 is a top view of a molded blank for a custom insole.  
         [0034]    [0034]FIG. 14 is a cross section of the molded cut blank of FIG. 13 taken along lines  14 - 14 .  
         [0035]    [0035]FIG. 15 is a cross section of the molded cut blank of FIG. 13 taken along lines  15 - 15 .  
         [0036]    [0036]FIG. 16 is a cross section of the molded blank of FIG. 13 taken along lines  16 - 16 .  
         [0037]    [0037]FIG. 17 is a cross section of the molded blank of FIG. 13 taken along lines  17 - 17 .  
         [0038]    [0038]FIG. 18 is a cross section of the molded blank of FIG. 13 taken along lines  18 - 18 .  
         [0039]    [0039]FIG. 19 is a block diagram showing a method of forming a complete digitized model of the height of a plantar contour of a foot of a user according to the present invention.  
         [0040]    [0040]FIG. 20 a  is a rear view of a foot placed into a dual density embodiment of the present invention.  
         [0041]    [0041]FIG. 20 b  is a side view of the dual density embodiment of FIG. 20 a.    
         [0042]    [0042]FIG. 21 is a schematic exploded side view of a partial women&#39;s heeled shoe, a dual density cartridge according to the present invention and a foot.  
         [0043]    [0043]FIG. 22 is a top view of the dual density cartridge of FIG. 21.  
         [0044]    [0044]FIG. 23 is a schematic side view of a foot positioned above a carrier filled with dual density foam according to the present invention.  
         [0045]    [0045]FIG. 24 is a schematic side view of a foot with pressure being applied thereto such that the dual density foam according to the present invention is depressed downward such that both the ball and heel of the foot are compressed into the higher density foam.  
         [0046]    [0046]FIG. 25 a  is a schematic side view of a foot positioned above a shorter three quarters sized dual density foam impression cartridge according to another embodiment of the present invention.  
         [0047]    [0047]FIG. 25 b  is a schematic side view of a foot with pressure being applied thereto such that the dual density foam impression cartridge of FIG. 25 a  is depressed downward such that only an impression of the heel and the arch are left.  
         [0048]    [0048]FIG. 26 a  is an exploded side view of a foot, a shorter three quarters sized dual density foam impression cartridge and a partial women&#39;s heeled shoe.  
         [0049]    [0049]FIG. 26 b  is a schematic side view of a foot positioned above a shorter three quarters sized dual density foam impression cartridge disposed within a partial women&#39;s heeled shoe.  
         [0050]    [0050]FIG. 26 c  is a schematic side view of a foot with pressure being applied thereto such that the dual density foam impression cartridge of FIG. 26 b  is depressed downward such that only an impression of the heel and the arch are left.  
         [0051]    [0051]FIG. 27 is a top planar view of a three quarters sized dual density foam impression cartridge according to the present invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0052]    Referring to the figures and more particularly to FIG. 1, an impression block  10  of the present invention is shown. Block  10  is made from pressure sensitive materials, which compress when a person&#39;s foot is pressed into the block. Preferably, block  10  comprises a casting material having low density, high flexural modulus and low shear strength. Accordingly, block  10  provides a material, which is easily deformed, with little or no memory, and retains the deformed shape indefinitely. Expanded phenolic materials such as those commonly used for insulation and ultra low density expanded polystyrene are suitable for block  10 . In the preferred embodiment, block  10  is expanded phenolic material.  
         [0053]    Preferably, block  10  has a hardness or density from about 0.5 to about 25 pounds per square inch (hereinafter “psi”). Selection of the correct block  10  density depends on factors such as body weight, lifestyle or desired usage (e.g., sport, casual, or formal). For example, a soft density is a density from about 0.5 to 5 psi, preferably 2 to 3 psi. Such soft density blocks  10  are selected for casting a foot in block  10  while in the sitting position. A medium density is a density from about 5 to 10 psi and is selected for casting a foot in block  10  while in standing position. A hard, weight bearing density is a density from about 5 to 25 psi, preferably 8 to 15 psi. Such hard density blocks  10  are selected for taking a dynamic casting of a foot in block  10 .  
         [0054]    Shown in FIG. 1, block  10  has a thickness  12 , a front or toe receiving end  14  and a rear or heel-receiving end  16 . Importantly, thickness  12  is sufficient to form an impression of at least a portion of the overall height of the user&#39;s plantar contour. In a first embodiment, thickness  12  is equal to less than half of the height of the plantar contour. In another embodiment, thickness  12  is equal to less than one third of the height of the plantar contour. More specifically, thickness  12  is in a range from about 8 mm to about 15 mm. In a preferred embodiment, thickness  12  of front end  14  is substantially identical to the thickness of rear end  16 . In alternate embodiments, thickness  12  of front end  14  is less than the thickness of rear end  16 .  
         [0055]    Accordingly, block  10  of the present invention is adapted to form at least a partial measurement of the user&#39;s plantar contour. As described herein by example, block  10  is adapted to form at least a partial measurement of the user&#39;s entire plantar contour. However, it is considered within the scope of the present invention for block  10  to be adapted to form at least a partial measurement of the only specific portion of user&#39;s plantar contour, such as, but not limited to, heel, arch and the like.  
         [0056]    As discussed above, a scanning system is used to digitize the measured contour. The digitized contour is provided to a computer controlled milling machine. The milling machine uses the digitized information to manufacturing a custom insole matching the digitized contour from an insole blank. The inventors have found that a complete plantar contour can be extrapolated from the partial measurement of the user&#39;s entire plantar contour.  
         [0057]    Preferably, block  10  is disposed in carrier or container  40 . Carrier  40  includes a front or toes receiving end  44  and a rear or heel-receiving end  46 . Block  10  is disposed in carrier  40  such that rear end  16  of the block is adjacent rear end  46  of the carrier and front end  14  of the block is adjacent front end  44  of the carrier.  
         [0058]    Carrier  40  is adapted for use as for taking an impression of either a left foot or a right foot. Preferably, carrier  40  shown in FIG. 2 is symmetrical about its longitudinal axis  41 . Thus, carrier  40  provides for sufficient surface area in both front end  44  and rear end  46  so as to allow the carrier to be used for either foot. Accordingly, carrier  40  reduces manufacturing costs by enabling a single mold to be used to manufacture the carrier and by eliminating the need to carry specific right foot carriers and left foot carriers in inventory.  
         [0059]    In an alternate embodiment, block  10  includes a guide  18  to ensure the user properly aligns the foot in the block. Guide  18 , shown in FIG. 3, is an indentation  19  formed within block  10 . Accordingly, guide  18  forms a natural locator for the user to place at least a portion of their foot into in order to align their foot in block  10 . Preferably, indentation  18  is adjacent rear end  16  of the block and is of sufficient depth to allow the user to align their heel with block  10 . In an alternate embodiment, indentation  18  is adjacent front end  16  of the block and is of sufficient depth to allow the user to align their toes with block  10 .  
         [0060]    By way of example, the use of block  10  to measure a person&#39;s plantar contour is described below with reference to the embodiment of block  10  shown in FIG. 1. The user positions one foot over block  10  with their toes toward front portion  14  and their heel towards rear portion  16  and moves their foot into the block as shown in FIG. 4. Next, the user applies weight to the foot on block  10  until the block is deformed to form a negative impression of at least a partial plantar contour  11 . Next, the user removes that foot from block  10  leaving the impression of the partial plantar contour  11  as shown in FIG. 5.  
         [0061]    As described above, impression of the partial plantar contour  11  formed in block  10  is used in the manufacture of custom insoles. The process of converting impression of the partial plantar contour  11  into the custom insole often times requires using a scanner to digitize the contour directly from the impression or by forming a positive model from the impression. By way of example the present invention is described using a scan taken directly from impression of the partial plantar contour  11 . However, it is considered within the scope of the present invention to include scanning from a positive model made from the impression.  
         [0062]    Partial plantar contour  11  is extrapolated to form a complete plantar contour  11 ′. Complete plantar contour  11 ′ is provided to a computer controlled milling machine. The milling machine uses complete plantar contour  11 ′ to manufacturing the custom insole from an insole blank. However, when desirable the partial plantar contour is all that is required for low profile insole supports.  
         [0063]    The scanning system forms a digitized model of partial plantar contour  11 . Periodic cross sections of partial plantar contour  11  are then generated. For example, a plurality of cross sections  15  shown in FIGS. 6 through 8 formed along lines  6 - 6  through  8 - 8  of FIG. 5 are generated. A sufficient number of cross-sections  15  to extrapolate complete plantar contour  11 ′ are formed. In the preferred embodiment, cross-sections  15  are generated in intervals of about 2 mm. However, for purposes of clarity only three cross sections  15  are described.  
         [0064]    By way of example, the formation of complete plantar contour  11 ′ from partial plantar contour  11  is described by the tangential line method shown in FIGS. 6 through 8. In this method, each cross-section  15  is analyzed at points  13  where partial plantar contour  11  exits block  10 . A tangent line  17  to partial plantar contour  11  at each point  13  is derived. Finally, the partial plantar contour  11  is continued along tangent line  17  to form complete plantar contour  11 ′. Thus, analysis of a plurality of cross sections  15  of block  10  having partial plantar contour  11  extrapolates complete plantar contour  11 ′.  
         [0065]    While the present invention is described above using the tangential line method, other prior art numerical methods including, but not limited to linear interpolation, quadratic interpolation, Newton&#39;s Forward-Backward-Difference interpolation, Everett interpolation, Lagrange interpolation and the like, are considered within the scope of the present invention for forming complete plantar contour  11 ′ from partial plantar contour  11 .  
         [0066]    Reduction in thickness  12  of block  10  provides numerous advantages over prior art blocks. For example, thickness  12  reduces shelf space requirements for block  10  at the point of sale, reduces packaging costs for block  10 , reduces the amount of block  10  that it required, thus reducing manufacturing costs and shipping costs, as well as damage that may occur during shipping. In the instance where block  10  is directed for use at home by the user and then to be shipped to a location for manufacture of the insole, reduced shipping costs provides a significant advantage. Additionally, thickness  12  enables the foot of the user to completely deform or bottom out in block  10 , which can provide a more accurate impression of the plantar contour.  
         [0067]    In an alternate embodiment, the present invention not only extrapolates complete plantar contour  11 ′, but also ensures that the complete plantar contour smoothly intersects the insole blank at a desired point. This requires a digitized model of, for example, the insole blank. The present invention is describe herein by example using types of insole blanks are commonly used to form custom insoles, namely die cut blanks  20  and molded blanks  30 . However, other types of blanks, such as, but not limited to, sheets of blank material are considered within the scope of the present invention.  
         [0068]    Die cut blank  20  is shown in FIGS. 9 through 12. A plurality of die cut blanks  20  are cut from a single sheet of insole forming material into the desired shape. For example, FIG. 9 a  shows die cut blank  20  in the form of a left foot insole. However, die cutting allows die cut blank  20  to be cut into other shapes, such as a right foot insole or a universal insole. Shown in FIG. 9 b,  die cut blank  20  has a constant thickness  22  across its length  23 . Thickness  22  of die cut blank  20  is typically between about 30 mm to about 35 mm.  
         [0069]    In order to ensure that the complete plantar contour smoothly intersects the insole blank, periodic cross-sections of the blank that correspond to cross-sections  15  of partial plantar contour  11  are generated. For example, a plurality of cross sections  25  shown in FIGS. 10 through 12 formed along lines  10 - 10  through  12 - 12  of FIG. 9 a  are generated of blank  20 . Shown in FIGS. 6 a  through  8   a,  cross section  15  of complete plantar contour  11 ′ is compared to each cross section  25  of blank  20 . The present invention smoothes intersection  27  of the complete plantar contour and blank  20 .  
         [0070]    In an alternate embodiment, the height of the sole of the shoe that the custom insole is to be placed is the desired point used to define intersection  27 . This requires a digitized model of, for example, the sole of the shoe that the custom insole is to be placed. In this embodiment, the point where each cross section  15  of complete plantar contour  11 ′ crosses the cross section of the sole of the shoe forms the intersection  27  of the blank and the completed plantar contour  11 ′. In the instance of low profile insole supports, smoothing will be required to fit them into higher blanks if they are used.  
         [0071]    Intersection  27  is smoothable by any number of smoothing methods such as, but not limited to, a radius fillet, bspline interpolation, and the like.  
         [0072]    Molded blank  30  is shown in FIGS. 13 through 16. Each molded blank is molded to have a predetermined shape and profile. For example, FIG. 13 shows molded blank  30  in the form of a left foot insole. However, molding allows molded blank  30  to be formed into other shapes, such as a right foot insole or a universal insole. Shown in FIGS. 13 through 15, molding molded blank  30  allows for a varying thickness  32  and width  34  across its length  33 . Thickness  32  of molded blank  30  typically ranges between a minimum of about 10 mm to maximum of about 35 mm, more preferably between 15 mm to 20 mm. For example, FIGS. 16 through 18 show various different cross-sections  35  taken along lines  16 - 16  through  18 - 18 , respectively, of FIG. 13.  
         [0073]    Similar to the discussion above with respect to die cut banks  20 , cross sections  35  of molded blank  30  that correspond to cross sections  15  of partial plantar contour  11  are generated by the scanning system. The scanning system compares each cross section  15  of complete plantar contour  11 ′ to cross section  35  of molded blank  30  and smoothes the intersection of the complete plantar contour and the molded blank. With extrapolation, the foot contour can be cut into insoles with approximately 10 mm in the arch and heal cups, and thereby provide the smoothing with the edges of the blanks.  
         [0074]    In an alternate embodiment shown in FIGS. 20 a  and  20   b,  block  10  is provided with a plurality of regions having different densities. By way of example, block  10  includes a region  10 - 1  having a first density and a region  10 - 2  having a second lower density. Thus, block  10  is adapted to manipulate the foot of the user during the forming of the impression. For instance, region  10 - 1 , being of higher density, ensures improved or better support for the heal and other plantar surfaces. In a preferred embodiment, region  10 - 1  has a density of 5 psi and region  10 - 2  has density of 3 psi. In this embodiment, the higher density of region  10 - 1  ensures that the foot is properly centered within the lower density region  10 - 2 .  
         [0075]    Also shown in FIGS. 20 a  and  20   b,  the inside  21  wall and outside  23  wall of carrier  40  are both shaped having a radius  42  between the sidewall and the bottom wall. Radius  42  is adapted to ensure that the heel of the user is properly centered within block  10 . Thus, radius  42  further improves the accuracy of the measurement of a person&#39;s foot by more closely approximating the position and shape their foot will assume when properly centered.  
         [0076]    [0076]FIG. 21 is a schematic exploded side view of a partial women&#39;s heeled shoe  80 , a dual density cartridge  82  comprising a first lower density layer  84  and second higher density layer  86 , and foot  88 . FIG. 22 is a top view of dual density cartridge  82 . FIG. 23 is a schematic side view of a foot  88  positioned above a carrier filled with dual density foam  82  prior to making a impression. FIG. 24 is a schematic side view of a foot  88  with pressure being applied thereto such that the dual density foam  82  is depressed downward such that both the ball  90  and heel  92  of foot  88  are compressed into higher density foam layer  86 .  
         [0077]    [0077]FIGS. 25 a  through  27  depict another embodiment according to the present invention wherein a foot  96  applies pressure to a shorter or partial (e.g., three quarters sized) dual density foam impression cartridge  98  comprising a first lower density layer  97  and second higher density layer  99 . FIGS. 26 a - 26   c  demonstrate cartridge  98  deposed within at least a portion of a shoe  100 , wherein shoe  100  acts as a carrier for cartridge  98 .  
         [0078]    It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims.

Technology Category: 1