Disposable footwear cover
The present invention relates to disposable protective footwear covers suitable for use in sterile environments, critically controlled environments, medical facilities, and industrial clean rooms.
1. Field of the Invention
The present invention relates to disposable protective footwear covers suitable for use in sterile environments, critically controlled environments, medical facilities, and industrial clean rooms.
2. Description of Related Art
Workers entering critically controlled areas need to don apparel to prevent substances released from the wearer's body from contaminating the environment. The apparel should not shed particles or fibers from the fabric. The apparel can further offer the worker protection from light liquid splash or dry particulates.
Boot and shoe covers are important to prevent tracking particles throughout critically controlled areas. Disposable footwear covers are used in the semiconductor and life science industries to prevent product contamination and exposure of the wearer to hazardous pathogens or materials.
Current footwear covers introduce additional hazards to the wearer such as slipping and tripping as a result of excess material contacting the floor. During use, current footwear covers can sag allowing material to drag on the floor creating a tripping hazard. Typical areas in which such material commonly contacts the floor and creates a hazard include the ankle area and metatarsal area.
U.S. Pat. No. 5,983,526 discloses a shoe cover of liquid impervious material with an elastic band completely encircling the ankle of the wearer. The patent does not teach the reduction of slipping and tripping hazards associated with the use of a shoe cover.
What is therefore needed is a disposable footwear cover that snuggly gathers excess material away from the floor to prevent slips, trips, and falls.
BRIEF SUMMARY OF THE INVENTIONThis invention relates to a disposable footwear cover having an inner surface, an outer surface, a lower leg region, an ankle region, a metatarsal region, a toe region, and a sole region the cover comprising:
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- a flexible polymer sheet;
- an elastic gather in the lower leg region;
- an elastic gather in the metatarsal region;
- an elastic gather in the ankle region; and
- a non-slip polymer coating covering at least 25 percent of the surface area of the sole region.
This invention also relates to a process for making the disposable footwear cover.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention relates to a disposable footwear cover for use in sterile environments, medical facilities, industrial clean rooms and the like that employs elastic gathers and a non-slip coating to provide the wearer additional protection against slips, trips, and falls.
The disposable footwear cover of this invention is prepared from flexible sheet materials, having an inner surface toward the wearer's foot or footwear and an outer surface away from the wearer's foot or footwear, formed into the general shape of a shoe, boot, or foot. The flexible sheet materials can be woven or nonwoven. Preferably, the flexible sheet materials are nonwoven. The flexible sheet materials can optionally include a coating over part or all of the surface to provide additional functionality, such as providing barrier properties. Further, the flexible sheet materials can optionally include bicomponent fibers to provide additional functionality, such as stability to gamma radiation for sterilization purposes. The bicomponent fibers are typically made of two distinct polymers and can be combinations of polyethylene, polypropylene or polyester. However, bicomponent fibers can be made from the same polymer having different properties. The bicomponent fibers can have sheath/core or side-by-side arrangement of the polymers. The flexible sheet materials useful in the present invention are typically liquid impervious and are chosen preferably to additionally act as a barrier to protect the wearer from such hazards as blood and chemicals.
Preferably, the flexible sheet material additionally acts as a barrier to the transmission of particles. More preferably, the flexible sheet material is able to prevent the transmission of greater than 85 percent of particles larger than 0.5 micrometers. Most preferably, the flexible sheet material is able to prevent the transmission of greater than 93 percent of particles larger than 0.5 micrometers.
Flexible sheet materials suitable for use in the present invention include but are not limited to microporous films, polyester and polyolefins. Preferably, the flexible sheet material comprises polypropylene or polyethylene. Polyethylene is preferred, for example TYVEK®, available from E. I. du Pont de Nemours and Co., Wilmington, Del. Flexible sheet materials suitable for use in the present invention can be produced by methods known in the art such as hydroentangling, carded thermal bonding, spunbonding, or meltblowing.
The invention as depicted in
The elastic gather of the lower leg region 50 typically encircles at least a portion of the leg of the wearer and can completely encircle the wearer's leg. The elastic gather of the lower leg region 50 can extend around all or a fraction of the circumference of the lower leg region. The elastic gather of the lower leg region 50 preferably encircles only a portion of the wearer's leg to allow for ease of donning. More preferably, the elastic gather of the lower leg region 50 encircles a portion of the back of the wearer's leg. Most preferably, the elastic gather of the lower leg region 50 encircles about 30 to 80 percent of the circumference of the wearer's leg at the area of contact.
The elastic gather of the ankle region 60 is typically placed as to gather excess material of the footwear cover and provide a snug fit. The elastic gather of the ankle region 60 can extend around all or a portion of the circumference of the ankle region 30. Preferably, the elastic gather of the ankle region 60 extends around 25 to 80 percent of the circumference of the ankle region 30 of the footwear cover. More preferably, the elastic gather of the ankle region 60 additionally extends around the back of the ankle. Most preferably, the elastic gather of the ankle region 60 extends around 25 to 60 percent of the circumference of the ankle region 30 of the footwear cover including the back of the ankle.
The elastic gather of the metatarsal region 70 is typically placed as to gather excess material of the footwear cover to reduce the possibility of tripping and provide a snug fit. The elastic gather of the metatarsal region 70 typically extends across the metatarsal region 20 from about one edge the sole to about the opposite edge of the sole.
A method for making the disposable foot cover is depicted in
Referring to
Coefficient of Friction is the dimensionless ratio of the friction force (F) between two bodies to the normal force (N) pressing these bodies together. The coefficient of friction is determined in accordance with ASTM D1894.
Coefficient of Static Friction is the coefficient of friction corresponding to the maximum friction force that must be overcome to initiate macroscopic motion between two bodies. The coefficient of static friction is determined in accordance with ASTM D1894.
Claims
1. A disposable footwear cover having an inner surface, an outer surface, a lower leg region, an ankle region, a metatarsal region, a toe region, and a sole region, the cover comprising:
- a flexible polymer sheet;
- an elastic gather in the lower leg region;
- an elastic gather in the metatarsal region;
- an elastic gather in the ankle region; and
- a non-slip coating covering at least 25 percent of the surface area of the sole region.
2. The disposable footwear cover of claim 1, wherein the flexible polymer sheet comprises a material selected from the group consisting of polyolefin and polyester.
3. The disposable footwear cover of claim 2, wherein the flexible polymer sheet comprises polyethylene.
4. The disposable footwear cover of claim 1, wherein the flexible polymer sheet is nonwoven.
5. The disposable footwear cover of claim 1, wherein the flexible polymer sheet is woven.
6. The disposable footwear cover of claim 1, wherein the polymer coating has a coefficient of static friction greater than about 1.5.
7. The disposable footwear cover of claim 1, wherein the non-slip coating comprises a material selected from the group consisting of polyvinyl chloride, polyolefins, polyester, rubber, polyurethane and combinations thereof.
8. The disposable footwear cover of claim 7, wherein the non-slip coating comprises polyester.
9. The disposable footwear cover of claim 8, wherein the polyester is coated with polyvinyl chloride.
10. The disposable footwear cover of claim 1, wherein the flexible sheet material blocks transmission of greater than about 85 percent of particles having an average diameter of greater than about 0.5 micrometers.
11. The disposable footwear cover of claim 10, wherein the flexible sheet material blocks transmission of greater than about 93 percent of particles having an average diameter of greater than about 0.5 micrometers.
12. A process for making a footwear cover of claim 1, comprising the steps of
- providing two sheets of polymer each having two long sides and a taper from a wide end to a narrow end,
- attaching the two sheets together at the narrow end of the taper,
- attaching the two sheets together for a partial distance on each of the long sides, thereby forming a small opening and an opposite large opening,
- providing a third sheet,
- forming the third sheet into a cylindrical shape,
- attaching the cylindrical third sheet to the small opening,
- providing a sole sheet,
- attaching the sole sheet to the large opening,
- attaching an elastic gather in the lower leg region,
- attaching an elastic gather in the metatarsal region,
- attaching an elastic gather in the ankle region.
Type: Application
Filed: Aug 30, 2005
Publication Date: Mar 1, 2007
Inventor: Rodger Harris (Hermitage, TN)
Application Number: 11/215,592
International Classification: A43B 3/16 (20060101);