Abstract:
A shoe heel includes a rigid heel block that attaches to a shoe sole at the heel seat on the sole and a top lift having a molded base that is located below the heel block such that a space exists between the bottom of the block and the top of the base. This space, along the peripheries of the block and base, contains&#39; a highly resilient skirt, the interior of which is for the most part a void. An elastomeric slug projects from the heel block, through the space, and at its lower end bears against the base of the top lift. The slug, while being resilient, possesses enough firmness to support the weight of an individual over the base of the top lift. The top lift contains pins which project from its base into bores in the heel block to prevent the top lift from rotating under the heel block. The slug, while transferring the weight of the individual to the top lift, attenuates impacts to which the top lift is subjected.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of application Ser. No. 09/352,645, filed Jun. 28, 1999 now abandoned May 31, 2001, and which is incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     This invention relates in general to footwear, and more particularly to a shoe heel that has the capacity to attenuate impacts encountered in walking or running. 
     An individual&#39;s normal act of walking—and even more so running—produces impacts that are transmitted primarily to the heel of the individual&#39;s foot, either directly when the individual walks or runs without shoes or indirectly when the individual wears shoes. Some shoes, such as sneakers, have outsoles and insoles which are molded from elastomers, and are thus capable of reducing the severity of the impacts. Indeed, some soles for sneakers have air bladders which even more effectively absorb impacts. But the traditional dress or casual shoe worn by women has a rigid heel with a thin sock lining over the heel seat at the upper end of the heel. Impacts transfer with little attenuation through the heel, heel seat and lining to the heel of the individual&#39;s foot, and can cause discomfort, particularly after long periods of walking or standing on hard surfaces. 
     To be sure, others have undertaken efforts to incorporate shock-absorbing devices into the heels of dress and casual shoes, but for the most part these efforts have not met with success. Some of these devices cannot withstand the impacts themselves. Others are too complex and cost too much to manufacture. The typical dress or casual shoe continues to have a solid heel which transmits impacts to the wearer&#39;s heel with little or no attenuation. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention resides in a shoe heel having a rigid block and a top lift which is coupled to the block such that the block may be depressed toward the top lift under moderate force, whereby impacts that would otherwise be transmitted to the heel of the wearer&#39;s foot are to a large measure absorbed in the heel. To this end, the heel block contains a slug of resilient material which projects from it and bears against the upper surface of the top lift. Being resilient the slug absorbs impacts. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a perspective view of a shoe having a heel constructed in accordance with and embodying the present invention; 
     FIG. 2 is an exploded perspective view of the heel; 
     FIG. 3 is a sectional view taken along line  3 — 3  of FIG. 1; 
     FIG. 4 is a sectional view taken along line  4 — 4  of FIG. 3; and 
     FIG. 5 is a sectional view taken along line  5 — 5  of FIG.  3   
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, a dress or casual shoe A (FIG. 1) has an upper  2 , which generally conforms to the shape of the user&#39;s foot and has the usual vamp  4  at its forepart, quarters  6  along its sides, a counter  8  at its rear and a top line  10  which provides an opening through which the wearer&#39;s foot is inserted. The shoe A also has a sole  14  to which the upper  2  is attached such that the sole  14  underlies the upper  2 . Beneath the vamp  4  of the upper  2  the sole  14  contacts the surface upon which the wearer walks, but the sole  14  also includes a shank  16  and heel seat  18  which are elevated from that surface, the heel seat  18  lying at the rear of the upper  2  in the region of its counter  8  and the shank  16  being immediately ahead of it beneath the quarters  6 . Finally, the shoe A has a heel  20  which is attached to the sole  14  at its heel seat  18  and indeed underlies the heel seat  18 . 
     The heel  20  basically includes (FIGS. 1,  2  and  3 ) a rigid heel block  22 , a top lift  24  located beneath the heel block  22 , and a decorative resilient skirt  26  located between the heel block  22  and the top lift  24 . In addition, the heel  20  has a slug  28  of resilient material (such as an elastomer) which extends from within the heel block  22  to the top surface of the top lift  24  and is firm enough to support the heel block  22  on the top lift  24  under the weight of the wearer. Yet the slug  28  is resilient enough to deform in the presence of impacts, so that impacts are attenuated through the slug  28 . The top lift  24 , like the forepart of the sole  14 , contacts the surface over which the wearer walks. It possesses some flexibility and extends fore and aft of the slug  28  so that it can flex toward the heel block  22  ahead of and behind the slug  28 . 
     The heel block  22  is formed from a rigid substance, preferably a molded polymer. It has (FIGS. 2 and 3) a top surface  30  which is contoured to conform to the bottom surface of the heel seat  18  for the sole  14 . Here the heel  20  is attached firmly to the heel seat  18 . The heel block  22  also has a flat bottom surface  32 , a front-surface or breast  34 , and side and back surfaces  36  and  38 . Generally midway between its breast  34  and back surface  38 , the heel block  22  contains a bore  40  (FIG. 3) which opens out of the bottom surface  32 , but is closed at its top. The axis of the bore  40  lies perpendicular to the bottom surface  32  of the heel block  22 . The bore  40  forms a cavity that is large enough to accommodate the slug  28 , and indeed the slug  28  fits into the bore  40  with its upper end against the top surface of the bore  40 . But the slug  28  is longer than the bore  40 , so that its lower end lies below the bottom surface  32  of heel block  22 . 
     In front of the bore  40 , the heel block  22  contains two guide bores  42  (FIG.  3 ), and to the rear of the bore  40 , the block  22  contains a single guide bore  44 . The guide bores  42  and  44  have their axes parallel to the common axis of the bore  40 , but they are considerably smaller in diameter. Each opens out of the bottom surface  32  of the heel block  22  at its lower end and into a counterbore  46  at its upper end, there being a shoulder  48  between each bore  42 ,  44  and its counterbore  46 . 
     The decorative resilient skirt  26  is formed from a highly flexible, low density, cellular material that provides substantially no shock attenuation. The skirt  26  has (FIGS. 2 and 4) a smooth exterior surface  50  and an elongated internal cavity  52  that extends completely through the skirt  26  and renders most of its interior a void. One polymer suitable for the skirt  26  is a microcellular polyurethane. The skirt  26  is attached with an adhesive to the bottom surface  32  of the heel block  22  with its exterior surface  50  flush with the breast  34 , side surfaces  36  and back surface  38  of the heel block  22 . The cavity  52  is large enough to leave the bore  40  and the three guide bores  42  and  44  exposed through the skirt  26 . Hence, the skirt  26  serves essentially to enclose the shock attenuation mechanism of the heel. 
     The top lift  24  includes a molded base  60  which is formed from a material that is more rigid than either the skirt  26  or the slug  28  and is reasonably resistant to wear, inasmuch as it comes against the surface over which the wearer walks, yet possesses a measure of flexibility. Rubber or polyurethane is suitable for this purpose. The base  60  has (FIGS. 2 and 3) a bottom surface  62  which is provided with ridges or some other pattern to enhance traction as well as a peripheral surface  64  and top surface  66 . The peripheral surface  64  conforms to the exterior surface  50  of the skirt  26  and indeed the top surface  66  is attached with an adhesive to the bottom of the skirt  24  such that the peripheral surface  64  of the top lift  24  lies flush with the exterior surface  50  of the skirt  26 . 
     In addition to the molded base  60 , the top lift  24  includes (FIGS. 2-4) two front stabilizing pins  70  and a single rear stabilizing pin  72 , each of which is firmly secured in the base  60  and projects upwardly from the base  60  perpendicular to its top surface  66 . The pins  70  and  72 , which lie parallel to each other, are preferably molded from a polymer which is somewhat flexible, but more rigid than the polymer of the base  60 . The front pins  70  align with and are received in front guide bores  42 , whereas the rear pin  72  aligns with and is received in the rear guide bore  44 . The stabilizing pins  70  and  72  allow the top lift  24  to move toward and away from the heel block  22 , but prevent it from rotating under the heel block  22 . As a consequence, the peripheral surface  64  of the top lift  24  remains in registration with the peripheral surface  64  of the skirt  26  and with the breast  34 , side surfaces  36  and back surface  38  of the heel block  22 . 
     Each stabilizing pin  70  and  72  has a foot  74 , the diameter of which is larger than the diameter of bore  42  or  44  into which the pin  70  or  72  fits. The foot  74  rises out of the top lift  24 , extending above the top surface  66  of the top lift  24  a distance that is less than one-half the thickness of the skirt  26  when it is unrestrained and more closely approaching one-third the thickness of the skirt  26 . At its lower end the foot  74  has a flange  76  which is embedded in the molded base  60 . In addition to its foot  74 , each pin  70  and  72  has a shank  78  which rises from the foot  74 . The shank  78  possesses a uniform diameter, and that diameter is slightly less than the diameter of the guide bores  42 ,  44 . Indeed, the shanks  78  for the pins  70  and  72  project into their respective guide bores  42  and  44  and when the skirt  26  is not deformed, they rise to the shoulders  48  at the upper ends of the bores  42  and  44 . At the upper end of its shank  78  each guide pin  70  and  72  has a head  80  which is larger in diameter than the bore  42  or  44  through which the shank  78  extends, but smaller in diameter than the counterbore  46  into which the bore  42  or  44  opens. The head  80  projects at a right angle over the shoulder  48  where the bore  42  or  44  opens into the counterbore  46 , and prevents the pin  70  or  72  from being withdrawn from the bore  42  or  44 . Each head  80  has a beveled leading surface  82  and an axially directed slot  84  which extends well into the shank  78 . This enables the head  80  and the shank  78  to contract, which facilitates assembly of the heel  20 . 
     Indeed, during assembly, the heads  80  of the pins  70  and  72  are aligned with the respective bores  42  and  44  for those pins  70  and  72 , and the entire top lift  24  is forced toward the heel block  22 . The heads  80  contract and pass through the bores  42  and  44 . Once the heads  80  enter the counterbores  46  at the upper ends of those bores  42  and  44 , they snap outwardly, thus locking the pins  70  and  72  in their respective bores  42  and  44 . More or less guide pins  70  and  72  may be used. For example, only a single guide pin  70  may be located ahead of the bore  40 . 
     The slug  28  fits into the bore  40  of the heel block  22  where its upper end bears against the closed end of the bore  40  (FIG.  3 ). The slug  28  projects downwardly out of the bore  40  and through the cavity  52  in the skirt  26 . Its lower end bears against the top surface  66  of the base  60  for the top lift  24 . Preferably the slug  28  is about 0.75 in. long and when unstressed it extends 0.25 in +/−0.010 in. between the bottom surface  32  of the heel block  22  and the top surface  66  of the top lift  24 . The diameter of the slug  28  when unstressed is only slightly smaller than the diameter of the bore  40 . Preferably the bore  40  has a diameter of 0.500 in. +0.020 in., −0.000 in., while the slug  28 , when unstressed, has a diameter of 0.480 in. +0.000 in. −0.020 in., leaving a clearance of 0.020 in. to 0.060 in. 
     However, the slug  28  may range in diameter from about 0.44 inches to about 0.56 inches which translates into cross-sectional areas ranging from about 0.15 in 2  to about 0.25 in 2 , should the slug be other than cylindrical. Of course, the bore  40  should conform in cross-sectional configuration to the slug, yet should be slightly larger. Moreover, the cross-sectional area of the slug  28  should be between about 7% and about 12% of the cross-sectional area of the bottom surface  60  on the top lift  24 . The rear most surface area on the cavity  40  should be set to at least 0.60 inches ahead of the rearmost portion of the back surface  38  of the heel block  22  and its forwardmost surface area should be set about 0.62 inches to about 0.68 inches behind the breast  34  of the heel block  22 , with the dimensions being along the bottom surface  32 . The lateral most surface areas on the slug  28  should be set inwardly from the side surface  36  of the heel block  22 , with the dimensions again being taken at the bottom surface  32 . 
     The slug  28  is formed from a material which is reasonably firm, yet has the capacity to deform elastically under a force. Thus, while the slug  28  supports the heel block  22  over the top lift  24  and thereby transfers the weight of the wearer to the top lift  24 , it has the capacity to yield somewhat so that impacts are absorbed by it. The slug  28  yields under a compressive force and in so doing expands into the cavity  52  where it remains unconfined laterally and also expands in the bore  40  as well. Elastomers are suitable for the slug  28 , polyurethane being particularly well suited. 
     In use, the wearer of the shoe A walks over pavement or some other surface with the usual stride and with each step the top lift  24  of the heel  20  first contacts the pavement and then the forepart of the sole  14 . Indeed, the rear most portion of the top lift  24  initially contacts the pavement and flexes slightly behind the slug  28 , and this to a measure absorbs some of the impact. But the top lift  24  then comes down flat against the pavement, the wearer&#39;s weight is transferred to the heel block  22  and through the slug  28  to the top lift  24 . While the descent of the top lift  24  abruptly ends, the heel block  22  continues downwardly owing to the elastic deformation of the slug  28  which in effect lies between the heel block  22  and the top lift  24 . As the slug  28  is compressed axially, it offers progressively more resistance to the compression and after about 0.20 to 0.23 inches of compression it supports the wearer without significant further deformation. As the slug  28  compresses it deforms into the cavity  52  of the skirt  24  and also in the bore  40  in which the slug  28  is located. The skirt  24  also deforms, but offers little support for the heel block  22 , since the material from which it is formed is considerably more resilient than the elastomer from which the slug  28  is formed. Extremely heavy forces bring the bottom surface  32  of the heel block  22  to the feet  74  on the pins  70  and  72 , and the feet  74  prevent further descent of the heel block  22 . 
     As the slug  28  compresses, the stabilizing pins  70  and  72  slide further into their respective guides bores  42  and  44 , but offer essentially no resistance to the descent of the heel block  22  toward the top lift  24 . The pins  70  and  72  also prevent the top lift  24  from rotating relative to the heel block  22 , so that when the wearer turns or pivots the shoe A, the top lift  24  follows heel block  22 . The pins  70  and  72  further add a measure of stability to the top lift  24  in that they rigidify it longitudinally and laterally and thereby retard significant rocking sideways or forwardly and backwardly beneath the heel block  22 , this being by reason of the generally rigid coupling between the feet  74  of the pins  70  and  72  and the base  60  of the top lift  24 . In this way, the pins  70  and  72  compensate for the relatively little lateral and longitudinal support provided by the skirt  26 . 
     This invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.