Abstract:
Improved adjustable midsole for footwear, with the midsole comprising an airtight, evacuable capsule containing granules and air, whereby the midsole is moldable to the shape of the wearer&#39;s foot for improved support and comfort, with the midsole retaining said shape through evacuation of air from the capsule. The improved midsole further comprises sipes such as slits or channels integrated into the midsole to improve flexibility.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates generally to the footwear industry. More specifically, the invention is directed to an improved adjustable midsole for use with articles of footwear whereby said improved midsole is conformable to the wearer&#39;s foot and thereafter may be reconformed as many times as desired. 
         [0003]    2. Description of Prior Art 
         [0004]    Footwear, and shoes in particular, in general terms are designed to provide the wearer with a combination of fit, cushioning, protection, and support appropriate to specific pursuits. The prior art describes shoes designed to mimic the support, stability, and cushioning characteristics of the human foot. Shoes have incorporated sipes, pressure-transmitting medium compartments, and inelastic, flexible fibers. Many shoes also incorporate a midsole component interposed between the foot bed and outsole. Midsoles have undergone an evolution in the past century from simple rubber material to more sophisticated modern polymers incorporating a variety of cushioning and so-called “motion-control” features. These elements, mostly found in athletic shoes, have been developed with varying degrees of actual measurable clinical effects. A variety of methods have been utilized in isolation and in combination to achieve these effects, including the use of open and closed cell foams, air, gels, springs, plastic trusses, and carbon fiber inlays. 
         [0005]    In addition to components directly integrated with the footwear, adjunctive methods of providing cushioning and support to the foot are also known in the art, including off-the-shelf arch supports and custom-molded foot orthotics. These devices are placed inside the shoe and are in direct contact with the wearer&#39;s foot. The obvious benefit of foot orthotics is the custom fit provided to the wearer. The remediation of biomechanical abnormalities of the foot is another potential benefit. 
         [0006]    One shortfall common to commercially available footwear is in the inability to readjust the fit to the wearer&#39;s foot anatomy. Current models provide a static shape midsole or arch support only. Similarly, custom-molded foot orthotics are typically shaped to the wearer&#39;s foot and then fixed to that customized fit, either through the application of heat or a chemical hardening agent. Once fixed, however, these orthotics are not reconformable. It would be highly desirable to have the ability to periodically readjust the fit of the shoe or insole to suit the wearer at any given time or during any given activity. The present invention overcomes this defect by providing a reconformable midsole through the use of an evacuable container to provide a vacuum cushion effect. The use of evacuable containers for shape retention is well known. These are most commonly used in hospital operating rooms as patient positioning devices. These devices typically comprise a flexible airtight sack containing small, elastically deformable granules which compress into a substantially rigid mass when air is removed from the sack. Before air is evacuated the granules fluidly move about within the sack so that the device can be formed to the desired shape. When air is removed from the sack, atmospheric pressure forces the granules together into a solid mass, thereby retaining the sack in the desired shape, customized to the anatomy of a patient placed thereon. Introducing air back into the sack returns the device to its initial condition, ready to be reshaped. 
         [0007]    The prior art reveals several devices incorporating a vacuum cushion effect in evacuable devices associated with the foot and ankle. One device describes using evacuable cushions about the foot and ankle to immobilize the wearer&#39;s anatomy after injury such as a fracture or surgery. While this device allows for a customized, reconformable fit, it is intended to immobilize the foot and ankle and is thus inappropriate for footwear designed for ordinary walking or running. Another device teaches an apparatus and method of use incorporating a bi-layered, evacuable foot bed designed to relieve pressure beneath certain anatomic locations on the plantar surface of the foot. This device is intended for use in diabetic patients with foot ulcerations. While this device is intended for footwear It does not incorporate means for enabling the natural flexion of the foot as seen during normal gait. That is, once the foot bed is conformed to the anatomy of the wearer&#39;s foot it becomes rigid. This configuration may be appropriate for standing, but it impedes normal movement. 
         [0008]    The present invention overcomes this problems of conformable midsoles found in the prior art through the incorporation of sipes in a variety of key locations enabling a more natural gait pattern. As more fully described below, the position of the sipes permits flexing of the midsole during walking or running while the foot is completely supported by the customized shape of the device. 
         [0009]    It is therefore an objective of the present invention to provide an improved adjustable midsole which may be easily conformed to the shape of the underside of the wearer&#39;s foot and which thereafter retains its shape as long as desired. 
         [0010]    It is a further objective of the present invention to provide an improved adjustable midsole which is easily reshaped as often as desired. 
         [0011]    It is yet a further objective of the present invention to provide an improved adjustable midsole which utilizes a vacuum cushion effect in order to provide a customized fit. 
         [0012]    It is yet a further objective of the present invention to provide an improved adjustable midsole which flexes to accommodate the natural biomechanics of the wearer&#39;s foot permitting a natural gait pattern during walking, running, or other like activities. 
         [0013]    It is yet a further objective of the present invention to provide an improved adjustable midsole which incorporates one or more sipes at specific locations thereby permitting a natural gait pattern during walking, running, or other like activities. 
         [0014]    It is yet a further objective of the present invention to optionally provide an improved adjustable midsole which can be removably inserted into footwear with the need for special tools. 
         [0015]    It is yet a further objective of the present invention to optionally provide an improved adjustable midsole which can be integrated into and made a permanent part of footwear. 
         [0016]    Other objectives of this invention will be evident from the following disclosure. 
       SUMMARY 
       [0017]    In accordance with the invention, the non-adjustable conformable midsole problem is solved by providing a malleable midsole which conforms to the shape of the underside of the human foot and then retains said shape for as long as desired, while also providing a simple means for easily and readily changing the configuration of the midsole to accommodate an infinite number of different foot shapes. The midsole further provides flexibility such that the midsole both retains its desired shape as well as flexes to accommodate the acts of walking, running, jumping, and the like. Such combination of midsole conformability and flexibility solves the problems of the prior art whereby a midsole was either conformable only a single time or, if adjustable, was inflexible, making it impractical for ordinary footwear use. The conformity of the midsole to the wearer&#39;s foot and the retention of this shape provides the wearer with an excellent fit. The adjustability of the midsole&#39;s shape allows it to adapt to any changes in the shape of the wearer&#39;s foot or to accommodate different therapeutic strategies. 
         [0018]    The improved midsole comprises an evacuable, flexible, airtight capsule containing a plurality of granules. The capsule is rendered malleable by introducing a quantity of gas, typically atmospheric air, into it. The midsole is adapted to conform to the sole of a human foot by the following process: the capsule is unsealed and a small quantity of gas is introduced into the capsule; a human foot is placed onto the capsule and downward pressure is applied, thereby causing the malleable capsule to conform to the sole of the foot; substantially all of the gas is evacuated from the capsule, thus causing the granules within the capsule to form into a rigid structure having substantially the same shape as the sole of the foot and further causing the capsule to be retained in the desired shape; and the capsule is sealed to prevent further introduction of gas into the capsule. At such time as the shape of the midsole is desired to be changed, gas is reintroduced into the capsule thereby rendering it malleable again, and the process is repeated. 
         [0019]    After the midsole has been formed into its desired shape, it retains partial flexibility by the use of one or more sipes integrated into the capsule. The use of sipes, which may be slits, channels, or flattened areas in the midsole, or any other structure allowing the midsole to flex, provides the midsole with the necessary flexibility to permit the dorsiflexion of the metatarsophalangeal joints of the human foot in the act of walking or running, thus making the midsole practical for use with ordinary footwear. 
         [0020]    In one embodiment the gas is evacuated from the capsule by a removable hand pump. In another embodiment a pump may be used to introduce gas into the capsule. In yet another embodiment the pump may be integrated with and made part of the midsole. Other means for introducing gas into and evacuation gas from the capsule are also anticipated, for example powered air compressors or suction devices. A sealable valve may be used to control the introduction and evacuation of gas into and out of the capsule. 
         [0021]    The improved midsole may be removably used in existing footwear, much like ordinary insoles, or it may be integrated with and made a permanent part of the footwear. 
         [0022]    Other features and advantages of the invention are described below. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a top view of the improved midsole of the present invention depicting the basic inventive elements. 
           [0024]      FIG. 2  is a top view of the improved midsole of the present invention depicting an alternate embodiment of the present invention. 
           [0025]      FIG. 3  is a perspective view of the improved midsole of the present invention. 
           [0026]      FIG. 4  is a perspective view of the improved midsole of the present invention. 
           [0027]      FIG. 5  is a perspective view of the improved midsole of the present invention in use with a human foot. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0028]    The present invention contemplates an improved adjustable midsole  10  for use with footwear, such as shoes, boots, sandals, sneakers, and the like. The midsole  10  is conformable to the underside of a human foot  5 , thereby providing greater support and comfort than traditional midsoles. See  FIG. 5 . Moreover, the midsole  10  is infinitely adjustable, so that as the shape of the wearer&#39;s foot  5  changes (either through injury or disease or just as a factor of aging), or as therapeutic needs require, the midsole  10  can be readjusted to provide a proper fit. 
         [0029]    The improved midsole  10  is comprised of a capsule  100 , one or more sipes  200 , a plurality of granules  300 , and means for introducing gas into the capsule  400 , evacuating gas from the capsule  500 , and sealing and unsealing the capsule  600 . See  FIG. 1 . The midsole  10  is divided into a forefoot portion  12 , a midfoot portion  14 , and a heel portion  16 , with the forefoot portion  12  located at the forward end of the midsole  10 , the heel portion  16  located at the rearward end of the midsole  10 , and the midfoot portion  14  located between the forefoot portion  12  and the heel portion  16  of the midsole  10 . See  FIG. 1 . 
         [0030]    The capsule  100  of the midsole  10  is fashioned of a sturdy, flexible material. This can be polyvinyl chloride, polyurethane, natural or synthetic rubber, or any other material that exhibits like characteristics. The basic shape of the capsule  100  is roughly that of the perimeter of the sole of a human foot  5 , with a wider forefoot portion  12 , a narrower midfoot portion  14 , and a heel portion  16  slightly wider than the midfoot portion  14  but narrower than the forefoot portion  12 . See  FIG. 1 . The capsule  100  is sealable, such that when it is unsealed a quantity of gas (typically atmospheric air) may be introduced therein or evacuated therefrom, and when it is sealed it becomes airtight. 
         [0031]    The capsule  100  is comprised of at least two sub-capsules  110 . See  FIG. 1 . Each sub-capsule  110  is adapted to be formed and fixed into an appropriate shape to conform to the underside of a foot  5 , as described above. Once fixed in shape, each sub-capsule  110  is substantially rigid, with minimal internal deformity. 
         [0032]    Each sipe  200  of the improved midsole  10  is integrated with the capsule  100  and is interposed between a pair of sub-capsules  100 . See  FIG. 1 . The sipe  200  may be a slit, a channel, or a flattened area formed into the capsule  100 . Its purpose it to increase the flexibility of the capsule  100  once the midsole  10  has been formed and its shape fixed. In one embodiment the sipe  200  is formed by bonding a portion of the upper surface of the capsule  100  to a portion of the lower surface of the capsule  100 . This bonding may be achieved by any means known in the art, such as by use of an adhesive, or by heat bonding, or by other appropriate means. In another embodiment the sipe  200  may be formed into the outer surface  130  of the capsule  100 . Other possible configurations of the sipes  200  are also contemplated by the present invention. 
         [0033]    The improved midsole  10  may have one or more sipes  200  which are substantially linear. See  FIG. 3 . In another embodiment one or more of the sipes  200  may be substantially curved. See  FIG. 1 . In yet another embodiment there may be a mix of substantially linear and substantially curved sipes  200  integrated into the capsule  100 . See  FIG. 2 . The substantially linear sipes  200  may be oriented at an optimal angle to the longitudinal axis of the midsole  10  to ensure appropriate flexing. This angle may be between sixty and ninety degrees to the longitudinal axis (e.g., between zero and thirty degrees to the transverse axis of the midsole  10 ). The configuration of the sipes  200  may also follow the metatarsal parabola wherein an arc may be described in a pattern over the metatarsal heads with the second metatarsal being the longest, the first metatarsal the second longest and metatarsals three, four, and five progressively shorter from medial to lateral. The choice of the specific configuration and orientation of the individual sipes  200  in any given midsole  10  is based on well-known properties of sipes  200  and is left to the individual. 
         [0034]    In its most basic configuration the improved midsole  10  will comprise a capsule  100  with a single pair of sub-capsules  110 , separated by one or more sipes  200 . One of the sub-capsules  110  will be located in the forefoot portion  12  of the midsole  10  and the other will be located in the midfoot portion  14  and heel portions  16  of the midsole  10 , with a sipe  200  located at the junction of the forefoot portion  12  and the midfoot portion  14  of the midsole  10 . During use the midsole  10  flexes along the sipe  200  such that the two sub-capsules  110  angulate in relation to each other. See  FIG. 4 . In other configurations there may be several sipes  200  interposed between the two sub-capsules  110 . In still other configurations there may be multiple sub-capsules  110 , whereby one or more sipes  200  are interposed between each pair of adjacent sub-capsules  110 . In such configurations, during use the midsole  10  flexes along the multiple sipes  200  such that the sub-capsules  110  angulate in relation to the other sub-capsules  110 . 
         [0035]    For each sub-capsule  110  there are one or more communications  120  with at least one other sub-capsule  110 . See  FIG. 1 . Each communication  120  is a gas permeable passageway connecting a pair of adjacent sub-capsules  110 . As such, the capsule  100  may have a single entry/exit point for the introduction and evacuation of gas, and gas entering that single entry/exit point can reach every sub-capsule  110  through the one or more communications  120 . In other embodiments, the capsule  100  may have multiple entry/exit points for the introduction and evacuation of gas, or entry point(s) independent from exit point(s). Similarly, gas can be evacuated from every sub-capsule  110  through the one or more communications  120  and out from the capsule  100  through the single entry/exit point. In one embodiment a pair of communications  120  is located at opposite ends of a sipe  200  separating a pair of adjacent sub-capsules  110 . See  FIG. 2 . Gas may move between the sub-capsules  110  around the ends of the sipe  200  through the pair of communications  120 . In another embodiment a single communication  120  is located at one end of the sipe  200 , with gas moving between the sub-capsules  110  through that single communication  120 . In yet another embodiment one or more communications  120  may be integrated with the sipe  200 , such that gas may move between adjacent sub-capsules  110  by passing through the sipe  200  itself. Each of the communications  120  is sized smaller than the smallest granule such that granules  300  may not pass into or through the communication  120 . 
         [0036]    The plurality of granules  300  are located within the sub-capsules  110  of the capsule  100 . See  FIG. 3 . The granules  300  are comprised of any light weight, deformable material, such as synthetic or natural rubber, EVA (ethylene vinyl acetate), an expanded plastic material such as expanded polystyrene, polyethylene, or the like. The granules  300  may be of a uniform, substantially spherical shape or may be irregularly shaped, though they should be substantially similar in size to each other, with the largest granules  300  being not more than five times larger than the smallest granules  300 . The granules  300  should be relatively small, not exceeding 5 millimeters in diameter, and more typically being between 0.1 and 1 millimeter in diameter. Because the one or more communications  120  between the sub-capsules  110  do not permit the passage of granules  300 , the granules  300  are kept within their sub-capsules  110 , ensuring an even distribution of granules  300  throughout the capsule  100 . 
         [0037]    Within the sub-capsules  110 , the granules  300  move amongst each other in a fluid relationship, allowing the capsule  100  to conform to the desired shape. When gas is evacuated from the capsule  100 , the granules  300  become tightly packed and compressed against each other, becoming immobilized in their relative positions to each other, thereby resulting in the capsule  100  retaining its desired shape. See  FIG. 5 . In one embodiment a mild adhesive is admixed with the granules  300 . The adhesive may be any type of non-hardening adhesive provided it does not prevent fluid movement of the granules  300  when the midsole  10  is being shaped. Use of the adhesive facilitates immobilizing the granules  300 , improving the ability of the capsule  100  to retain its desired shape after gas is evacuated from it. However, because the adhesive is non-hardening, the midsole  10  may be reconfigured with the introduction of gas into the capsule  100 , as described above. 
         [0038]    The present invention contemplates various means for introducing gas into the capsule  400 , evacuating gas from the capsule  500 , and sealing and unsealing the capsule  600  to either prevent or allow either the introduction of gas into the capsule or the evacuation of gas from the capsule  100 . In one embodiment, the means for introducing gas into the capsule  400  comprises a pump  410 . See  FIG. 1 . The pump  410  may be a hand pump or a foot pump. In a preferred embodiment the pump  410  has a nozzle which is inserted into the capsule  100  when gas is being introduced, and then removed when the process is complete. In another embodiment the pump  410  has a threaded end which is threaded onto a mating thread integrated with the capsule  100  during use. In yet another embodiment the pump  410  is integrated with the capsule  100  and made a permanent part thereof. See  FIG. 3 . In such a configuration the pump  410  may include a bulb and hose, where one end of the hose is integrated with the capsule  100  and the bulb is attached to the opposite end of the hose. Squeezing the bulb forces air through the hose and into the capsule  100 . In yet another embodiment the pump  410  may be a removable powered air compressor. 
         [0039]    Similarly, the means for evacuating gas from the capsule  500  may comprise a pump  510 . See  FIG. 1 . The pump  510  may be a hand pump or a foot pump. In a preferred embodiment the pump  510  has a nozzle which is inserted into the capsule  100  when gas is being evacuated, and then removed when the process is complete. In another embodiment the pump  510  has a threaded end which is threaded onto a mating thread integrated with the capsule  100  during use. In yet another embodiment the pump  510  is integrated with the capsule  100  and made a permanent part thereof. See  FIG. 3 . In such a configuration the pump  510  may include a bulb and hose, where one end of the hose is integrated with the capsule  100  and the bulb is attached to the opposite end of the hose. Squeezing the bulb draws air through the hose and out of the capsule  100 . In yet another embodiment the pump  510  may be a removable powered suction device. 
         [0040]    In yet another embodiment the same pump  410 , 510  may be used to both introduce gas into the capsule  100  and to evacuate gas from the capsule  100 . See  FIG. 3 . Such a pump  410 , 510  may have a nozzle to be inserted into the capsule  100  during use, or may have threads for mated engagement with the capsule  100 , or may be integrated and made a permanent part of the capsule  100 . Such a pump  410 , 510  comprises a valve or valves which control the movement of gas, either out of the pump  410 , 510  or into the pump  410 , 510 , to achieve both the introduction and evacuation of gas functions. 
         [0041]    In one embodiment the means for sealing and unsealing the capsule  600  to either prevent or allow either the introduction of gas into the capsule or the evacuation of gas from the capsule  100  comprises a sealable valve  620 . See  FIG. 1 . The sealable valve  620  is integrated and made a permanent part of with the capsule  100 . In another embodiment the sealable valve  620  is positioned flush with the outer surface  130  of the capsule  100 . The pumps described above may be inserted into the unsealed sealable valve  620  to force gas into the capsule  100  or to draw gas out of the capsule  100 . When the pump is removed the sealable valve  620  is sealed to prevent further movement of gas into or out of the capsule  100 . In one embodiment the means for introducing gas into the capsule  400  comprises the sealable valve  420  itself. See  FIG. 2 . Upon unsealing the sealable valve  420 , gas moves through the sealable valve  420  and into the capsule  100  by means of air pressure differentials. With this embodiment a one-way pump  510  may be used solely to evacuate gas from the capsule  100 . In yet another embodiment the means for sealing and unsealing the capsule  600  to either prevent or allow either the introduction of gas into the capsule or the evacuation of gas from the capsule  100  comprises a pump  610  integrated with and made a permanent part of the capsule  100 , as described above. Such a pump  610  comprises a valve or valves which control the movement of gas, both allowing movement and preventing movement of gas. The pump  610  may be a multi-function pump, adapted to both introduce and evacuate gas, as described above, or it may be a single function pump adapted solely for evacuating gas. If a single function evacuation pump is used there is also a need for a separate means for introducing gas into the capsule  400 , such as a separate sealable valve  420 , as described above. 
         [0042]    In one embodiment the midsole  10  is suitably adapted to be easily inserted into and removed from an article of footwear without the use of tools. In this embodiment the midsole  10  is used much like an ordinary insole. This permits an ordinary article of footwear to be retrofitted with the functionality of the improved midsole  10 . It also allows the midsole  10  to be alternated among different articles of footwear so that expense is kept to a minimum. 
         [0043]    In another embodiment the midsole  10  is integrated with and made a permanent part of an article of footwear. In this embodiment the midsole  10  is added to the article of footwear during the manufacturing process. While this limits the ability to use the midsole  10  with different articles of footwear, it allows for a more custom fit with the article of footwear. 
         [0044]    Those skilled in the art will perceive improvements, changes and modifications in the invention. Such improvements, changes and modifications within the skill of the art are intended to be covered by the claims set forth herein, and that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.