Orthopedic cast cover and method of manufacture

A waterproof, orthopedic cover for use over an injured limb and a method for producing the cover is disclosed. The cover is composed of polyurethane and has a receiving end through which the injured limb is inserted. A closed end is also present and designed to accommodate either a hand or a foot. The polyurethane cover is bounded by a pair of seams which render the cover tear resistant.

TECHNICAL FIELD 
The subject invention relates generally to protective covers and their 
manufacture and more specifically to a waterproof, orthopedic cover for 
use over an injured limb. 
BACKGROUND OF THE INVENTION 
Injured areas must often be protected with a cast, bandage or other 
protective dressing. These areas should be kept dry and free from water or 
other moisture. Plaster casts disintegrate when wet and even casts made 
from synthetic materials such as fiberglass should be kept moisture-free 
to prevent the cast lining from deteriorating and the skin under the cast 
from macerating. 
Commonly used protective devices include a bag and strap variety such as 
disclosed in U.S. Pat. Nos. 4,562,834 and 4,363,317. These devices consist 
essentially of a large vinyl bag with a string or strap to secure the open 
end of the cover over the affected area. These covers suffer from several 
drawbacks. First, they are relatively difficult to put on an arm without 
assistance since the string or strap must be manipulated around the cast 
or bandage. Additionally, many of these devices are not truly watertight 
and cannot be completely submersed. Further, the material from which these 
bags are constructed is subject to tearing when in contact with rough 
fiberglass cast edges, thus rendering the coverings useless. 
Another commonly used cast protector consists of a thin latex bag as 
described in U.S. Pat. Nos. 4,043,326 and 4,139,003. These bags tear 
easily, failing to last the full convalescence period. Additionally, these 
devices may fit improperly and can be so tight that blood flow is 
restricted or so loose that they leak. 
Another protective device consists of a vinyl bag with a flat latex 
diaphragm and collar as described in U.S. Pat. No. 4,639,945. Although 
generally more effective than the bags disclosed above, the vinyl used is 
susceptible to tears. The diaphragm must be cut to size for most patients, 
a practice to which some patients and orthopaedic technologists object. 
The present invention overcomes the above-noted shortcomings of 
conventional protective coverings. The covering can be applied easily 
one-handed, without assistance. The material used is durable, flexible and 
provides an effective watertight seal. Thus, the covered limb can be 
completely submersed and still maintain a waterproof environment within 
the protective cover. These and other advantages of the subject invention 
will become apparent to those skilled in the art upon a reading of the 
Description of the Preferred Embodiment together with the drawings. 
SUMMARY OF THE DISCLOSURE 
A waterproof, orthopedic cover for use over an injured limb and a method 
for making the cover is disclosed. The cover comprises a polyurethane 
enclosure that includes a receiving end defining an opening through which 
an injured limb is inserted. The opening is configured to form a 
watertight seal around the limb and over a cast or other protective 
dressing. 
The enclosure includes a closed end that is either mitten or sock-shaped to 
fit over a hand or foot, respectively. 
The cover is manufactured by folding a polyurethane sheet in half resulting 
in three open edges and a folded end. The three open edges are sealed to 
form an enclosure; a hole is cut into the folded end; and the enclosure is 
turned inside out. 
The enclosure of this invention as made by the method of this invention is 
folded at the receiving end where the opening is located and includes at 
least one seam surrounding the remainder of the enclosure. This enclosure 
can also include pull tabs at the sides of the receiving end.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIGS. 1 and 2, a protective limb cover according to the 
present invention can be seen. Limb cover 10 is an enclosure with a closed 
end 12 and receiving end 14. Limb cover 10 also includes at least one and 
preferably two seams 16 running substantially around the closed end 12 to 
receiving end 14. 
As best illustrated in FIGS. 3 and 4, receiving end 14 defines an opening 
18, for receiving an injured limb. The term limb as used herein refers to 
an arm, leg, forearm or lower leg which might be protected by a bandage, 
cast or other dressing. Opening 18 has a diameter less than the diameter 
of receiving end 14 and the limb to be protected. In this way, limb cover 
10 can fit snugly over the injured area and maintain a watertight seal 
between the injured limb and the external environment. Preferable 
diameters of the opening 18 range from 1 inch to 5 inches, depending on 
the age of the patient and the circumferences of the limb proximal to the 
injured area. For instance, a limb cover to fit over an average casted 
adult arm would have an opening 18 with a diameter of approximately 2 to 
21/2 inches. 
As illustrated in FIGS. 2 and 6, closed end 12 can be mitten-shaped with a 
thumb compartment 13 for use over an injured arm or sock-shaped for use 
over an injured leg. In this way, a patient's hand or foot can fit 
comfortably within the enclosure. 
The seams 16 resist tears that might occur due to sharp and bulky casts. 
This problem more often occurs in the prior art when a large foot cast 
comes in pressure contact with the protective cover. 
Seams 16 can be formed using radio frequency (RF) heating to seal the 
closed end 12. An RF sealer, such as a 10 kilowatt unit, is employed in 
the present invention. The sealer applies a current to a brass die, in the 
desired shape of a mitten or sock, that transfers heat to the limb cover 
undergoing manufacture. Sealing time takes 2-4 seconds. 
As best illustrated in FIGS. 1-4, adjacent to and continuous with seams 16 
are tabs 22 to aid in pulling the limb cover 10 over the injured area. 
Tabs 22 are peak-shaped and formed by the intact portion of the receiving 
end 14 that borders on the seams 16. Tabs 22 will be discussed in greater 
detail below. 
Limb cover 10 is composed of heavy-gauge film polyurethane which combines 
durability and elasticity. Film polyurethane can stretch to five times its 
length and return to within 3% of its original length. Thus, opening 18 of 
limb cover 10 can be stretched over the protective dressing and return to 
its original size to fit snugly around the limb to be protected. Film 
thickness ranges from 0.005 to 0.020 inches and preferably 0.005 to 0.010 
inches thick are utilized. 
Limb cover 10 can be fabricated using single piece construction in the 
following manner. The polyurethane film is cut to a length more than two 
times the length of the completed limb cover. The film is then folded over 
with a fold 13 at the receiving end 14 forming a front side 15a and a back 
side 15b (FIG. 5A in which the ultimate outline of the sealed periphery is 
shown in phantom). A mitten or sock-shaped, RF heated brass die is pressed 
against the folded film to make the seal 16 between the front and back 
sides 15a and 15b from two spaced apart positions along the fold 13 (FIG. 
5B). Seal time takes approximately 2-4 seconds. 
Next, opening 18 is formed by punching a semi-circular hole across the fold 
13 at the folded receiving end 14 using a die-type punch. This produces a 
circular opening when limb cover 10 is in use (FIG. 5C). The size of the 
opening can be varied to accommodate different limb sizes. The excess 
polyurethane film is then trimmed from around seams 16. (FIG. 5C) and the 
limb cover is turned inside out (FIG. 5D). Air pressure can be used to 
uniformly turn limb cover 10 inside out, as well as assure that no hole or 
weak seam is present through which water might leak while the limb cover 
is in use. 
When limb cover 10 is turned inside out, seams 16 are positioned in the 
interior of the limb cover 10 (FIG. 5D). This not only serves an aesthetic 
purpose, but also helps to hold the sides of the enclosure apart thereby 
functioning to ease insertion of an injured limb into opening 18. Further, 
as illustrated in FIGS. 3 and 4, when limb cover 10 is turned inside out, 
the corners of the remaining fold in the receiving end form peaks 22 that 
function as handles to aid in pulling the limb cover 10 over the injured 
appendage. When limb cover 10 is pulled over the limb to be protected, 
opening 18 enlarges to accommodate the extra width imposed by the cast or 
dressing. Limb cover 10 is placed completely over the cast and opening 18 
shrinks back to its original diameter to snugly hug the injured limb. 
Thus a watertight, protective covering for use with a cast, bandage or 
other dressing is disclosed. Although a preferred embodiment of the 
subject invention has been described in some detail, it is understood that 
obvious variations can be made without departing from the spirit and scope 
of the invention as defined by the appended claims.