1. Field
This invention concerns the field of pads or cushions for the human foot.
2. Background
The human foot has irregular contours that vary considerably among individuals. Footwear is incredibly diverse in style and construction and is commonly selected from a limited collection of sizes for an adequate fit. Wearers frequently select footwear based on style and appearance with fit as only a secondary consideration. While some footwear features adjustability of fit through laces, adjustable straps, or the like, it is very rare that a particular shoe exactly fits a particular foot. Further, feet vary in contour and dimension during movement and throughout the course of a day in response to fatigue, applied pressure, hydration, and other factors. As a result, the fit between a shoe and the wearer's foot is frequently less than perfect.
Poor fit between a foot and footwear can lead to irritation, pain and injury. Further, even well-fitted shoes can irritate a pre-existing injury. It is thus beneficial to improve the fit between foot and footwear and to cushion and protect the foot to reduce or prevent discomfort or injury.
This is not a new problem, but earlier approaches have been less than adequate. Such approaches may be conveniently divided into devices that attach to or insert into footwear and devices that attach to the foot directly.
U.S. Pat. No. 2,090,573 is typical of devices designed to be attached to footwear. A crescent-shaped cushion is adhered by adhesive to the vamp of a shoe to cushion the foot and prevent the upper edge of the shoe at the vamp from biting into the foot. The crescent shape permits a reasonable match to the contour of the dorsum of the foot, but it is not designed for any other area. Once installed in a shoe, the cushion protects the wearer's foot only while wearing that shoe.
U.S. patent application publication 2010-0018074A1 describes a cushion insole designed to be inserted and adhered into a shoe. The insole includes marks indicating where the user may trim the insole to adjust the fit. The need to trim the device to accurately fit the wearer's foot, while allowing a more precise fit, puts a preparation burden on the wearer. Further the shape conform only to one area of the foot, limiting its application.
U.S. Pat. No. D570488 illustrates a device that attaches to the foot. A soft foam cushion surrounded by a clear flexible adhesive plastic attaches to the ball of the foot to provide comfort while walking. The roughly oval cushion is apparently only held to the foot by the surrounding adhesive, making it possible for the material of the cushion to shift or separate from the foot during motion. Further the shape appears to roughly conform only to one area of the foot, limiting its application.
U.S. Pat. No. 2,619,961 describes a bunion pad intended to be secured to the foot. A contoured cushion partially encircles a bunion, callous, or corn and separates the encircled area from the pressure of a shoe. The bunion pad may be placed in a number of different locations on the foot, but its flat shape will buckle if applied to an area that significantly departs from flat portions of the foot. The shape of the bunion pad is designed to conform to a small area of irritation that it may partially encircle. The relatively small size of corns and bunions permits the pad be similarly small in size, avoiding buckling in most applications. It is thus not applicable to use for larger areas or for areas where there is a significant departure from flatness.
U.S. Pat. No. D547948 illustrate a tri-lobe planar wound heel dressing that becomes non planar to conform to the shape of a heel. The dressing includes three triangular cut outs that divide it into three lobes. An illustration shows the opposite edges of each cut out brought into contact with one another to form the dressing into a cup-shaped structure. The patent illustrates the cup-shaped structure in contact with a heel of equal size. This design may conform to a properly-sized heel but does not appear applicable for other size heels or other areas.
U.S. Pat. No. 7,847,143 discloses a dancer's protective foot pad designed to be worn in place of other footwear. The foot pad adhesively adheres to the ball of the dancer's foot. The shape of the foot pad and a locating tab that extends between the wearer's toes limits the application of the foot pad to the ball of the foot.
U.S. patent application publication 2004/0237165A1 discloses flexible footwear that attaches adhesively to the plantar surface of the foot. Among illustrated embodiments are a first embodiment (shown in FIG. 1) resembling a footprint and a second embodiment (shown in FIG. 8) that is generally circular with a radial slit. Each includes an adhesive on the foot contact surface.
The wearer may trim the material of the first embodiment to conform to the size and shape of the wearer's foot. The adhesive presumably retains each portion in place and permits relative motion of separated portions (such as the individual toe portions). The flexibility of the device permits at least some flexing of the foot during walking. Because this device conforms in shape to the footprint, its use is as a practical matter limited to application on the bottom of the foot. Further, the need to trim the device to accurately fit the wearer's foot, while allowing a more precise fit, puts a preparation burden on the wearer.
The wearer may further adjust the second embodiment by folding the flaps on either side of the slit so that one flap overlaps the other. This forms the embodiment into a cup-shaped toe piece that better conforms to the bottom of the toes. The cup-shaped toe piece thus includes a double-layer overlap region that is of greater thickness than the non-overlapped region of the device, a situation that may produce discomfort while walking. The folding process also puts a preparation burden on the wearer.
These adhesive footwear devices are thus limited in their application area. This limitation is entirely consistent with their purpose of protecting the plantar surface of the foot in place of other footwear.
Thus there remains a need for a cushioning device that may conform to the contour of an individual foot without trimming or other adjustment, that is usable with multiple sets of footwear, that conforms to a variety of locations on the foot, and that prevents discomfort or irritation without detracting from the appearance of footwear or wearer.