Patent Publication Number: US-6662473-B2

Title: Shoe with ergonomic insole unit

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a shoe, particularly, to a shoe which has an ergonomic insole unit incorporated therein. 
     2. Description of the Related Art 
     Conventional lasts for making shoes generally have planar bottom faces at heel regions. Although manufacturers are aware that the wearers&#39; heels are substantially semicircular at their bottoms, lasts used in lasting heels are not provided with a bottom having the same profile as that of the wearer&#39;s heel since the bottom profile of the lasts cannot accommodate a heel lasting machine. A heel lasting machine normally has a wiper blade that traverses the bottom face of a last so as to fold and press a lower margin of an upper over and against an insole supported by the last bottom. As the wiper blade traverses linearly and immediately below the last, the last is provided with a planar surface ( 1 A), as shown in FIGS. 1A and 1B, so as to avoid interference with the movement of the wiper blade. If the last bottom is convex, the insole and/or the bottom margin of the upper can be damaged by the wiper blade, and difficulties will be encountered in the heel lasting process. 
     Since the last bottom is planar, the insole used in a lasted shoe is usually planar. The planar insole is insufficient to cushion and comfort the wearer&#39;s foot since it does not contact and support sufficiently all parts of the foot other than the foot palm and the heel. Stress concentration thus occurs at the foot palm and the heel due to the weight of the wearer&#39;s body. The heel can even get injury at the calcaneus in case of prolonged wearing of the shoe incorporating such planar insole. 
     It is known to provide a last with a bottom face conforming to the bottom of the wearer&#39;s foot in manufacturing a sandal since no heel lasting machine is used in making the sandal. An example of such a last is shown in FIG. 2A &amp; 2B at  2  and has a convex bottom face  2 A. A sandal  3  made by using the last  2  is shown in FIG.  3  and has a foot bed  31  which can be in proper fit with the wearer&#39;s foot to support all areas of the foot bottom so that the weight of the wearer can be distributed to all parts of the foot bottom. Such a foot bed can not be provided in shoes, such as sport shoes, walking shoes, etc., which are produced via heel lasting machines. 
     It is usual to provide a shoe with a reinforcement piece, such as, a counter or stiffener, at the heel section of the shoe. For example, U.S. Pat. No. 4,622,764 discloses a molded shell made of a rigid material, such as a rigid plastic or metal, so as to reinforce the rear portion of the shoe. The molded shell is placed at the outer side of an upper and a lasted insole, and is assembled with the upper after the upper is lasted. As both of the molded shell and the insole have planar top and bottom faces, they do not conform to the wearer&#39;s heel. 
     To comfort the wearer&#39;s foot, it is conventional to place inside a shoe a removable foot pad which is concave at the top face thereof to match the convex bottom of the wearer&#39;s heel. However, although the foot pad is thick at the lateral parts thereof, the central concave part of the foot pad is usually thin and does not have enough thickness to cushion the convex part of the wearer&#39;s heel since the total thickness of the foot pad is limited by the height of the interior space of the shoe which is determined by a last used in manufacturing the shoe. If the foot pad is too thick, it would affect the originally predetermined dimensions of the interior space of the shoe. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a shoe with an ergonomic insole unit which has a concave support face to match the contour of the convex bottom of the wearer&#39;s heel and which still permits a conventional heel lasting machine to perform a heel lasting operation though using a last with a heel section conforming to the wearer&#39;s heel. 
     Another object of the present invention is to provide a shoe with an ergonomic insole unit which has a concave support face to match the contour of the convex bottom of the wearer&#39;s heel and which still has a concave part with a thickness sufficient to cushion the wearer&#39;s heel. 
     Still another object of the present invention is to provide a shoe with an ergonomic insole unit which has a concave support face to match the contour of the convex bottom the wearer&#39;s heel and which can still be united with a conventional outsole that can be mass-produced. 
     Accordingly, a shoe according to the present invention comprises an ergonomic insole unit, and an upper having a top end disposed above the insole unit and a bottom margin attached directly to the insole unit, the insole unit including a heel part which includes a base and a rear upward flange projecting upward from a periphery of the base and making a U-shaped turn around the base, the upward flange extending inwardly of the bottom margin of the upper, the base having a planar bottom face,the rear upward flange having an outer surface extending upward from the planar bottom face of the base and forming a corner with the planar bottom face, the heel part further having a concave inner surface opposite to the outer surface and the bottom face, the inner surface extending gradually upward and outward along a direction from a mid part of the base to a top end of the upward flange and having a curved face extending along the corner, the heel part having, between the planar bottom face and the inner surface, a thickness which decreases gradually from the upward flange toward the mid part. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which: 
     FIG. 1A is a side view of a conventional last which is planar at the bottom of a heel region thereof; 
     FIG. 1B is a rear view of the conventional last of FIG. 1A; 
     FIG. 2A is a side view of another conventional last which is convex at the bottom of a heel region thereof; 
     FIG. 2B is a rear view of the conventional last of FIG. 2A; 
     FIG. 3 is a perspective view showing a sandal and the conventional last of FIGS. 2A and 2B; 
     FIG. 4 is a sectional view of a shoe embodying the present invention; 
     FIG. 5 is another sectional view of the shoe taken along line  5 — 5  of FIG. 4; 
     FIG. 6 is a perspective view of a heel part of an insole unit shown in FIG. 4; 
     FIG. 7 is a sectional view taken along line  7 — 7  of FIG. 6; 
     FIG. 8 is a sectional view taken along line  8 — 8  of FIG. 6; 
     FIG. 9 is an elevation view showing an insole element and the heel part of FIG. 4, both of which are mounted on a last; 
     FIG. 10 is the same view as FIG. 5 but with the insole element being placed beneath the heel part; 
     FIG. 11A is a perspective view showing another heel part according to the present invention; 
     FIG. 11B is a cross-sectional view taken along line  11 B— 11 B of FIG. 11A; 
     FIG. 12 is a perspective view of another insole unit according to the present invention; 
     FIG. 13 is a perspective view of a toe part of the insole unit according to the present invention; 
     FIG. 14 is a perspective view of another toe part of the insole unit according to the present invention; 
     FIG. 15 is a perspective view of a modified form of the toe part of FIG. 13; 
     FIG. 16 is a perspective view of a modified form of the toe part of FIG. 14; 
     FIG. 17 is a perspective view of a modified form of the heel part of FIG. 6; 
     FIG. 18 is a perspective view of a modified form of the heel part of FIG. 11A; 
     FIG. 19 is an elevation view of another shoe embodying the present invention; 
     FIG. 20 is a perspective view of a shank part usable in the present invention; and 
     FIG. 21 is a perspective view showing a heel part which is smaller in size than a heel section of an insole element according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 4 &amp; 5, a first embodiment of a shoe  10  according to the present invention comprises an upper  20  connected to an ergonomic insole unit which includes an insole element  21  and a heel part  30  connected to the insole element  21  via connection means, such as adhesive bonding, sewing or mechanical fasteners, etc. The upper  20  has a bottom margin  201  provided around the insole element  21  and the heel part  30 . The bottom margin  201  is attached to the insole element  21  and the heel part  30  via a lasting process. 
     The heel part  30  may be fabricated via a molding process from a rigid, semi-rigid, or flexible plastic material. The plastic materials usable for the heel part  30  include PVC, PU, EVA, EPE, etc. Referring to FIGS. 6,  7  and  8 , the heel part  30  includes a base  301 , and a rear upward flange  302  extending upward from the base  301  and making a substantially U-shaped turn around the base  301 . The base  301  has a planar bottom face  304  which forms a corner  305  with an outer surface  306  of the upward flange  302 . The heel part  30  further has an inner surface  307  which is opposite to the planar bottom face  304  and the outer surface  306 . The inner surface  307  is concave and extends gradually upwardly and outwardly along a direction from a mid part of the base  301  to a top end of the upward flange  302 . The height of the inner surface  307  from the bottom planar face  304  decreases gradually from the upward flange  302  toward the mid part of the base  301 . The curvature  308  of the inner surface  307  opposite to the corner  305  has a diameter greater than 8 mm. 
     The insole element  21  has a toe section  211 , a shank section  212 , and a heel section  213 , like the conventional insole. The insole element  21  is made of a flexible material such as PVC, EVA, a woven or non-woven fabric, or the like. The insole element  21  has a substantially uniform thickness, and the heel section  213  of the insole element  21  is placed above the base  301  of the heel part  30 . In assembly, the insole element  21  and the heel part  30  are mounted on a bottom side of a last  40  as shown in FIG. 9 to undergo a lasting operation in a conventional manner. During the lasting operation, the upper  20  is also mounted on the last  40 , and a portion of the bottom margin  201  is folded over and attached to the planar bottom face  304  of the heel part  30 . The remaining portion of the bottom margin  201  of the upper  20  is folded over and attached to the bottom face of the insole element  21 . After the lasting operation, the upper  20 , the insole element  21  and the heel part  30  are assembled with an outsole  50  via a conventional soling process, such as a direct injection process to form the outsole  50 , a cementing process to cement the outsole  50 , or a goodyear welt process to attach a goodyear welt and the outsole  50 . 
     Although the last  40  has a bottom profile substantially conforming to the bottom face of the wearer&#39;s foot like the last  2  shown in FIGS. 2A and 2B, it is feasible to use the last  40  to fabricate the shoe  10  by using a conventional heel lasting machine since the heel part  30  has the planar bottom face  304 . The height of the inner surface  307  of the heel part  30  increases gradually from the mid part of the base  301  of the heel part  30  to the top of the upward flange  302 , the inner surface  307  of the heel part  30  conforms to the bottom convex surface of the wearer&#39;s heel which is the lowest at the mid part of the heel and becomes higher gradually to the lateral side thereof. The insole element  21  follows the contour of the concave inner surface  307  the heel part  30  and contacts and supports almost all area of the wearer&#39;s heel. In addition, since the insole unit, comprised of the heel part  30  and the insole element  21 , is attached directly to the bottom margin  201  of the upper  20  when it is mounted on the bottom face of the last  40 , the thickness of the insole unit or the heel part  30  is not limited by the interior space of the upper  20  into which the last  40  is inserted. The heel part  30  thus has a sufficient thickness to cushion the bottom face of the wearer&#39;s heel beneath the calcaneus. 
     Referring to FIG. 10, the heel part  30  may be placed above and connected integrally with the insole element  21 . In assembly, the heel part  30  together with the insole element  21  is mounted on the last  40  (shown in FIG. 9) to connect with the bottom margin  201  of the upper  20 . 
     Instead of the heel part  30  described hereinbefore, the ergonomic insole unit according to the present invention may be configured to include a heel part  30 A as shown in FIGS. 11A and 11B. The heel part  30 A has a base  301 A and an upward flange  302 A which are substantially the same as the base  301  and the flange  302  of the heel part  30  except that the base  301 A is provided with an opening  309 A in a mid part thereof. Like the heel part  30 , the inner surface  307 A of the heel part  30 A has a varying height which decreases gradually from the upward flange  302 A toward the mid part of the base  301 A. 
     Referring to FIG. 12, the ergonomic insole unit according to the present invention is configured as a single piece member  30 B including a heel part  301 B, a shank part  302 B and a toe part  303 B. The heel part  301 B has substantially the same configuration as the heel part  30 . The shank part  302 B and the toe part  303 B may be designed such that they are more flexible and have a lower hardness than that of the heel part  301 B. The single-piece member  30 B may be constructed in such a manner that they have different levels of hardness at the heel, shank and toe parts  301 B,  302 B and  303 B. Furthermore, the hardness of the single piece member  30 B may be the same or different at the shank and toe parts  302 B and  303 B. When the single piece member  30 B is used, the upper  20  may be lasted with or without the insole element  21 . 
     Referring to FIGS. 13 and 14, the ergonomic insole unit in the present invention may also include a separate toe part  31 , or a separate toe part  32  to be used together with the heel part  30  or  30 A. The toe part  31  in FIG. 13 has a front upward flange  312  projecting upward from the periphery of the toe part  31  and having a U-shaped turn along the periphery of the toe part  31 . The toe part  32  in FIG. 14 has a front upward flange  322  projecting upward from the periphery of the toe part  32  and having a U-shaped turn along the periphery of the toe part  32 . In assembly, the toe part  31  or  32  may be placed above or below the insole element  21 , like the heel part  30  or  30 A and mounted on the last  40  (shown in FIG. 9) together with the insole element  21 . 
     Referring to FIGS. 15 and 16, reference numerals  31 A and  32 A represent respectively another toe parts which are modified forms of the toe parts  31  and  32 . The toe part  31 A has an additional front outward flange  313 A which projects outward from an upward flange  312 A along a plane substantially parallel to a planar bottom face (not shown) of the toe part  31 A. The toe part  32 A has an additional front outward flange  323 A which projects outward from an upward flange  322 A along a plane substantially parallel to a planar bottom face (not shown) of the toe part  32 A. 
     Referring to FIGS. 17 and 18, reference numerals  30 C and  30 D represent respectively another heel parts which are modified forms of the heel parts  30  and  30 A. The heel part  30 C has an additional rear outward flange  301 C which projects outward from an upward flange  302 C along a plane substantially parallel to the planar bottom face (not shown) of the heel part  30 C. The heel part  30 D has an additional rear outward flange  301 D which projects outward from an upward flange  302 D along a plane substantially parallel to a planar bottom face (not shown) of the heel part  30 D. 
     Referring to FIG. 19, the heel part  30 C or  30 D and the toe part  31 A or  32 A have the outward flanges  301 C or  301 D and the outward flanges  313 A or  323 A thereof connected to an outwardly turned bottom margin  201 A of an upper  20 A. The heel part  30 C or  30 D and the toe part  31 A or  32 A are disposed above the insole element  21  and are interconnected integrally. Assembly of the upper  20 A with the insole element  21 , the heel part  30 C or  30 D and the toe part  31 A or  32 A is accomplished via a conventional stitchdown process using the last  40  which is shown in FIG.  9 . 
     Referring to FIG. 20, the ergonomic insole unit according to the present invention may also include a separate shank part  33  which can be used in combination with the heel part  30  or  30 A and the toe part  31  or  32 . The shank part  33  has two opposite lateral upward flanges  331  which project upward from two opposite ends of the shank part  33 . In assembly, the shank part  33  may be placed above or below the insole element  21  together with the heel part  30  or  30 A and/or the toe part  31  or  32  and connected to the bottom margin  201  of the upper  20 . 
     Referring to FIG. 21, the heel part  30 A maybe configured with a size smaller than the heel section  213  of the insole element  21  so that the periphery of the insole element  21  extends beyond and projects outwardly of the periphery of the heel part  30 A when the heel part  30 A is disposed above the insole element  21 . The outwardly projecting part of the insole element  21  may be connected to the outwardly turned bottom margin  201 A of the upper  20 A shown in FIG.  19 . 
     As mentioned hereinbefore, due to the use of the ergonomic insole unit according to the present invention, a shoe can be produced via a conventional heel lasting machine while still using a last  2  shown in FIGS. 2A and 2B. In addition, since the insole unit is attached directly to the bottom margin  201  of the upper  20  or the bottom margin  201 A of the upper  20 A while it is being mounted on the bottom face of the last  40 , the insole unit is permitted to have an increased overall thickness with a sufficient thickness at a region corresponding to the wearer&#39;s calcaneus. The insole unit can provide support for all areas of the wearer&#39;s heel so that the weight of the wearer can be distributed to all areas of the heel and the problem of stress concentration caused to the heel face beneath the calcaneus can be alleviated. 
     While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.