Various shoe inserts are used to provide comfort, support, cushioning, and/or stability to the foot. For individuals suffering from serious podiatric conditions, such as abnormal walking patterns, custom orthotics prescribed by a physician are necessary. One drawback of custom orthotics is that they are generally expensive and time-consuming to fabricate. For other individuals, off-the-shelf, pre-formed, shoe inserts provide sufficient support and comfort.
An intermediary option where an off-the-shelf insert that is conformed to an individual's foot either at the time of purchase of the insert or thereafter, without the participation of a physician has been taught in various manners and is generally known in the prior art. Such instant moldable orthotic insoles need no mold, lab, weeks of waiting and are available at a greatly reduced cost.
U.S. Pat. Nos. 5,203,793, 5,101,580, and 4,674,206 to Lynden, teach several sole insert devices containing conformable material substantially comprising fluid matter which forms a resilient material substantially comprising solid matter after a working time. In more specific examples, Lynden teaches a personalized insert containing a resilient material, which comprises at least two compartments separated by a restraining pin or one or more membranes, which compartments separate two reagents that, when mixed, catalyze to form an insert resilient material. Removal of restraining pin(s), and/or the rupture of the membranes isolating the reagents, permits fluid communication and proper mixing of the reagents to form the resilient material. The resilient material then sets in conformance with the wearer's foot when the insert is secured within an article of footwear.
The sole insert devices taught by Lynden have the two reagents separated from each other using a pin dividing a bag. This is a very ineffective means to mix the silicone thoroughly and quickly.
To overcome the shortcomings in the Lynden devices, the present invention uses a static mixer with the strong force of the weight of the wearer pushing it though the mixer. This allows the use of a higher viscosity silicone, which helps to fit the wearers fit without requiring the user to sit still for more than a few minutes.
A common problem in the prior art is the use of lower viscosity fluids are likely to escape into areas at the edge of the bag that make it much harder to receive a complete mixing and therefore do not provide even support throughout the insole. The present invention overcomes this shortcoming by using a static mixing device built into the arch of the shoe and limiting the areas to which the silicone can flow. The advantage is that the silicone will completely mix before even entering the area under the arch and therefore cure very quickly while the user can still stand still. This can only be achieved with high viscosity silicone because low viscosity silicones will otherwise return to a neutral position until the silicone is more advanced in it's curing.
Still another disadvantage of Lynden's system is that the bag lies flat under the insole providing very little support other than that shaped by the silicone.
It is therefore an objective of the present invention to build the silicone injection system into an already supportive insole so that the silicone will provide only the amount needed for customization above the minimum that most wearer's will likely need. This is achieved by housing the static mixer in the arch of the sole that is already providing some support while hiding the mixer.
Yet another shortcoming in Lynden's system is its complicated use. A user needs to access the insole outside of the shoe, remove the pin and while the fluid is beginning to cure, put it in the shoe and stand in the right position on both feet. This process is confusing and difficult for the average user. It is therefore an objective of the present invention to teach a device that is less complex in its use.
The present invention is designed without the need for a pin, tab or key of any sort to initiate activation. To use, a user simply stands in the shoe and the fluid is injected and mixed. This insures that the exact timing of the curing and shaping of the silicone is always the same because no delay is possible between activating the curing and standing on the insole.
U.S. Pat. No. 5,958,546 to Mardix, et al., teaches a method for producing a custom insole including the steps of providing a preformed insole precursor, the precursor being constructed of a solid material which is storable in an unreformed state and which is compressible to a deformed configuration under pressure substantially at room temperature and which retains the deformed configuration after removal of the pressure, and pressing the foot on the insole precursor, thereby compressing the insole precursor and forming an insole with a configuration in accordance with the configuration of the foot.
U.S. Pat. Nos. 5,042,100 and 5,095,570 to Bar et al. teaches techniques for producing an insole for a foot, including defining a flexible insole housing in which is disposed a deformable material impregnated with an uncured resin, activating the resin for initiating curing thereof, locating the foot on the insole housing and allowing the resin to harden and to therefore preserve the configuration defined by the bottom of the foot. Bar's device is impractical as an off the shelf product. It still has the same problems as the Lynden Devices, problems of even mixing and control of timing from the point of being put on a user's foot.
U.S. Pat. Nos. 4,385,024, 4,128,95 to Tansill, teach a moldable article, such as an insole, which comprises a formable material that is a moldable polymeric or prepolymeric substance that can be cured to a form stable state and a curing agent, in close proximity to the curable substance but isolated there from, in a frangible container. The container containing the curing agent is initially flexible and is rendered frangible by treatment. In use, the frangible container is ruptured to release the curing agent, and the moldable article, in a first configuration, can be shaped to a second configuration in which it is maintained until the formable material is cured sufficiently for it to be form-stable in the second configuration.
Tansill suffers from the same disadvantages as Lynden since no static mixer. In Tansill's device, a user first needs to rupture the bag containing the catalyst that then needs to be shaken up resulting in a delay. Although with better mixing then Lynden, Tansill's device can't be compare to an internal static mixer and the pressure of someone standing on the heel to push the fluid through at equal ratio.
U.S. Pat. No. 6,098,315 to Hoffmann, III, teaches an insert for a shoe comprising a pouch having a moldable, thixotropic material and a shell having a catalyst. The shell is capable of being ruptured by massaging the pouch to allow the catalyst to be released from the shell and mixed with the material. In use, the pouch is massaged to mix the catalyst and moldable material and is then placed in a shoe. The user places a foot in the shoe and applies a lightweight to the foot so that the pouch assumes the shape of the foot bottom and fills that space between the foot and the shoe. The foot is then removed to allow the material to cure.
The device of Hoffmann requires puncturing, massaging, and manual injection of catalyst, massaging again to mix properly, insertion into a user's shoe and then removal from shoe in order to cure. The process is much too slow and risky due to its complexity, timing of wearing the insole from the point of mixing the catalysts, and risk of shape changing at the beginning of curing process. It is therefore an objective of the present invention to provide an apparatus that is quick and simple to use.
U.S. Pat. No. 5,083,910 to Abshire, et al., teaches a custom fitted insole assembly for use in a shoe directly under a wearer's foot. The assembly includes a heel-cupping and arch-supporting base component custom contoured to fit the heel and arch of the wearer's foot, a heel stabilizing component attached to an underside heel region of the base component, and a shock-absorbing top sheet component sized to underlie the bottom of the wearer's foot and at its rear half to overlie and conform to the contour of the base component.