Waterproof Prosthetic Foot and Method of Making Same

1. Field of the Invention

The present invention pertains to prosthetic devices and, more particularly, to an improvement for waterproofing a prosthetic foot.

2. Discussion of the Prior Art

Many people must utilize prosthetic feet in order to perform normal daily tasks; however, while prosthetic feet have been improved in order to facilitate walking, running and other physical activities, no prosthetic foot has been developed to date which will permit a wearer to immerse the foot in water, such as while showering, bathing or swimming. When a conventional prosthetic foot is immersed in water, the water will seep into the interface between the wood block, called the keel, and the foot body molded around the keel, such seepage causing warping of the keel and rendering the prosthetic foot defective for normal use. Accordingly, it has been the practice in the past for a wearer of a prosthetic foot to remove the foot prior to engaging in any activity where the foot would be exposed to water. Removal of the prosthetic foot has the disadvantages of being time consuming, presenting a disconcerting appearance and causing a situation where the person must awkwardly transport himself from a swimming pool, beach or the like without the use of the prosthetic foot. Normally, a person utilizing a prosthetic foot also requires an artificial leg; and, thus, the problem of transporting oneself becomes increasingly difficult.

There have been attempts in the past to waterproof prosthetic feet, as exemplified by U.S. Pat. No. 1,812,156 to Leaf, U.S. Pat. No. 2,103,511 to Brown, and U.S. Pat. No. 2,451,980 to Samons, Sr. and Russian Pat. No. 381,347; however, prior attempts have suffered the disadvantages of not being useable with conventional prosthetic foot structures, of rendering the prosthetic foot stiff and difficult to utilize for normal activities and/or of being relatively fragile and requiring continued inspection and maintenance when used on hard and abrasive surfaces.

Accordingly, it is a primary object of the present invention to overcome the above-mentioned disadvantages of the prior art by providing an improvement for waterproofing a conventional prosthetic foot while permitting the prosthetic foot to remain flexible and not requiring a change in structure of the prosthetic foot.

Another object of the present invention is to secure a layer of water repellent resilient material to a prosthetic foot to withstand continued use directly on abrasive surfaces while maintaining the prosthetic foot in a watertight condition.

A further object of the present invention is to cement a layer of water repellent resilient material to the lower portion of a foot body of a prosthetic foot and coat an upper portion of the foot body with a water repellent material to cover the interface of the layer of water repellent resilient material with the foot body, the layer of water repellent material and the coating material being resilient to permit the prosthetic foot to retain normal flexibility.

The present invention has a further object in that conventional, commercially available prosthetic feet can be waterproofed without altering the structure or characteristics of the feet.

Some of the advantages of the present invention over the prior art are that the method of waterproofing a prosthetic foot according to the present invention is simple and inexpensive to implement while being extremely effective and long lasting, and the waterproofing materials can be simply and inexpensively replaced should they be worn from use.

The present invention is generally characterized in an improvement for waterproofing a prosthetic foot formed of a keel adapted to be coupled with a lower end of an artificial leg portion and a foot body surrounding the keel and having an upper portion and a lower portion defining a toe, a heel and a bottom surface extending from the toe to the keel, the improvement including a layer of water repellent resilient material secured to the bottom surface of the foot body extending from the toe to the heel, and a coating of water repellent material covering the top portion of the foot body and the interface of the edges of the layer of water repellent resilient material with the foot body whereby the prosthetic foot can be immersed in water while water is prevented from reaching the keel.

The present invention is further generally characterized in a method of waterproofing a prosthetic foot of the type having a keel and a foot body surrounding the keel and having an upper portion and a lower portion defining a toe, a heel and a bottom surface extending from the toe to the heel including the steps of cementing a layer of water repellent resilient material to the lower portion of the foot body with a waterproof sealing adhesive, and coating the foot body with a water repellent material to cover the upper portion of the foot body and the interface of the edges of the layer of water repellent resilient material with the lower portion of the foot body.

Other objects and advantages of the present invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings.

FIG. 1 is a perspective view of an improved waterproof prosthetic foot according to the present invention.

FIG. 2 is a perspective view of the improved waterproof prosthetic foot of FIG. 1 with parts broken away.

FIGS. 3, 4 and 5 are cross-sectional views illustrating a method of waterproofing a prosthetic foot according to the present invention.

A waterproof prosthetic foot 10 according to the present invention is illustrated in FIGS. 1 and 2 and includes a block of wood forming a keel 12 adapted to be coupled with a lower end of an artificial leg 14 via any conventional coupling, such as a ball and socket joint or the like, and a foot body generally indicated at 16 having an upper portion 18 and a lower portion 20 defining a toe 22, a heel 24 and a bottom surface 26 extending from the toe to the heel. The prosthetic foot, as thus far described, is conventional; and, thus, no additional detailed description thereof is set forth, it being noted that the foot body 16 is normally formed of a soft resilient material, such as polyurethane resin, molded around the keel 12 such that the toe and ball of the foot body present a flexibility similar to that of walking on a normal foot.

In accordance with the present invention, a substantially flat sole 28 of water repellent resilient material is cemented to the bottom surface 26 of the foot body with a waterproof sealing adhesive 30, and a strip or band of water repellent resilient material 32 extends substantially transversely from the edges of the sole 28 and is cemented to the front, rear and side edges of the foot body and to the edges of the sole 28 by means of the waterproof sealing adhesive 30. If desired for situations where the prosthetic foot 10 is subjected to overly abrasive conditions, such as walking in sand, the band of material 32 can have an overlapping portion 34 extending inwardly over the toe, heel and sides of the lower portion 20 of the foot body. A coating 36 of water repellent material, such as silicone rubber, covers the upper portion 18 of the foot body 16 and the interface of the lower portion foot body with the band of material 32.

Preferably, the sole 28 and band 32 are made of the same material which should be wear-resistant as well as water repellent. Examples of materials which are suitable for such purposes are natural or synthetic rubber, such as butyl rubber, styrene-butadiene copolymers and polyene rubbers, such as polybutadiene and neoprene. The adhesive 30 can be any waterproof, sealing cement, such as Barge All-Purpose Cement.

A method of waterproofing to form the prosthetic foot of FIGS. 1 and 2 is illustrated in FIGS. 3, 4 and 5 and includes initially the step of cementing the sole 28 to the bottom surface 26 of the foot body 16 with cement 30, the sole 28 extending from toe 22 to heel 24. Thereafter, the band of material 32 is cemented in place with its lower edge overlapping the side edge of the sole and the wider portion 34 extending over the toe 22, as shown in FIG. 4. Once the sole 28 and band 32 are cemented in place, the foot is coated with silicone rubber 36, as shown in FIG. 5, to cover the upper portion 18 of the foot body and the interface of the upper edges of the band 32 with the lower portion of the foot body.

If desired, the sole 28 and the band 32 can be stapled in place to add structural stability to the sealing characteristics of the adhesive 30. Additionally, the sole 28 and the band 32 could be integrally formed of a single piece of water repellent resilient material if desired.

Inasmuch as the present invention is subject to many variations, modifications and changes in detail, it is intended that all subject matter discussed above or shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.