A stocking for use in positioning a pulsatile bladder about a portion of a user's body is described. The stocking is desirably circularly knit to have an inner sleeve, and an outer sleeve extending concentrically over the inner sleeve. The inner sleeve desirably is knit to provide a graduated degree of compression along the underlying portion of a person's body when the stocking is positioned on a wearer's limb. The outer sleeve is preferably relatively less elastic than the inner sleeve, so as to prevent a bladder positioned within the stocking from pressing uncomfortably into a wearer's flesh. The outer sleeve also desirably includes first and second spaced-apart openings, one for bladder insertion and the other for allowing the exit of tubing typically associated with pulsatile bladders. The stocking is preferably integrally knit on a circular knitting machine such that it comes off of the machine in finished form.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention generally relates to a pulsatile anti-embolism stocking. More 
specifically, the invention relates to a pulsatile anti-embolism stocking 
which can be produced in finished form on a circular knitting machine. 
2. Description of the Prior Art 
Persons having restricted mobility due to injury or infirmity are often 
faced with additional physical problems as a result of their lack of 
movement. For example, decreased circulation resulting from lack of 
movement can cause the formation of air bubbles or clots in a person's 
blood vessels. Such emboli can be life threatening, as they can occlude 
the blood vessels and/or travel to the heart or brain, with serious or 
fatal results. Similarly, decreased circulation can cause death or decay 
of tissue (e.g. gangrene) which in severe cases, can require removal of 
the affected limb. 
To avoid such consequences, doctors often provide their bedridden or 
movement restricted patients with devices which reduce the tendency of 
emboli to form. For example, commonly assigned U.S. Pat. No. 3,975,929 to 
Fregeolle describes a circularly knit anti-embolism stocking which 
provides a graduated compressive force along the leg of a wearer. The 
stocking of the Fregeolle patent is described as being thigh length and 
including a leg portion having an extension formed of partial courses 
extending upwardly therefrom around a portion of the stocking 
circumference, and an elastic band extending from one side of the 
extension to the other and around the remaining stocking circumference. 
The knit structure is also described as being modified along the length of 
the stocking in order to provide graduated compression therealong. 
Another device which is designed to improve circulation is the pulsatile 
bladder. Such bladders are designed to be positioned proximate a portion 
of a user's body where circulation is to be improved (typically on a 
limb), and a fluid such as air is pumped through the thus-positioned 
bladder in a pulsating manner to increase circulation of blood through the 
underlying blood vessels in the limb. In order to maintain the pulsatile 
bladder in the desired position on a wearer's body it must be secured in 
some manner, preferably by one which is comfortable to the wearer. One 
method of securing such a bladder to a wearer's body is by way of a 
specially designed stocking adapted to accommodate and retain the bladder 
in position. 
Stockings adapted to accommodate a pulsatile bladder typically include a 
knitted tubular calf-covering member, to which a foot covering member is 
secured. Such stockings generally include a substantially rectangular 
piece of fabric having a first longitudinal side secured along the length 
of the calf-covering member, and a substantially free second longitudinal 
side. A first half of a zipper is secured along the length of the second 
longitudinal side of the rectangular piece of fabric, with the mating 
zipper half being secured along the length of the calf-covering member in 
a spaced relationship to the first longitudinal side of the rectangular 
piece of fabric. In this way, when the zipper is zipped together, the 
piece of fabric wraps around a major portion of the calf-covering member 
in a layered relationship therewith. The substantially rectangular piece 
of fabric is also typically folded inwardly (i.e. towards the 
calf-covering member) along its widthwise-extending sides, so as to form 
pockets along the upper and lower sides of the piece of fabric. In this 
way, the pockets can retain a pulsating bladder between the substantially 
rectangular piece of fabric and the tubular calf-covering member, such 
that it can encourage blood flow through the blood vessels of a wearer's 
underlying leg. In addition, a button hole-type opening is generally 
located proximate a lower end of the piece of fabric, for allowing tubing 
associated with the bladder to extend therethrough outwardly from the 
bladder pocket. 
Because these conventional pulsatile bladder-retaining stockings require 
seaming of the zipper halves in the appropriate location, seaming of the 
piece of fabric to the calf-covering member, and the formation of 
ravel-stop means along all of the raw edges of the pieces of material, the 
amount of labor involved in their production tends to be very high. As a 
result, such stockings tend to be very costly to manufacture. Further, 
positioning of a pulsating bladder with respect to such a stocking and a 
user's body is limited, since the bladder pocket does not extend around 
the entire circumference of the stocking. In other words, the bladder must 
necessarily be positioned at a specific predetermined location on the 
stocking, which depends upon the positioning of the piece of fabric with 
respect to the calf-covering member. In addition, the zipper can tend to 
bear against the wearer's leg, causing discomfort or irritation thereto. 
Thus a need exists for a means for securing a pulsatile bladder to a 
wearer's body which is inexpensive to manufacture, comfortable to the 
wearer, and which allows good positioning of the pulsatile bladder with 
respect to the user's body. 
SUMMARY OF THE INVENTION 
With the foregoing in mind, it is an object of the present invention to 
provide a stocking for stably and comfortably securing a pulsatile bladder 
to a user's body which requires only a minimal number of production steps. 
It is also an object of the present invention to provide a method for 
manufacturing a stocking for securing a pulsatile bladder to a wearer's 
body using only a minimal number of manufacturing steps. 
It is a further object of the invention to provide a system for reducing 
the formation of emboli which is effective and comfortable, and which 
requires only a minimal number of manufacturing steps. 
In accordance with these objectives, the invention relates to a circularly 
knit, pulsatile anti-embolism stocking (hereinafter "PAE stocking") which 
comes off of the knitting machine in substantially finished form, and a 
method for making such a stocking. The stocking desirably includes an 
inner tubular sleeve and an outer tubular sleeve which is relatively less 
elastic than the inner sleeve, and which extends coextensively about the 
inner sleeve. In a preferred form of the invention, the inner and outer 
tubular sleeves are secured together about their respective upper and 
lower ends, to define a cylindrically-shaped pocket region therebetween. 
In a particularly preferred form of the invention, the inner and outer 
sleeves are integrally knit together such that their respective ends are 
secured together during the knitting process, without the need for 
additional processing steps. In a further preferred form of the invention, 
the inner sleeve is knit such that it will provide graduated compression 
along the length of the appendage onto which the stocking is positioned. 
This graduated compression can be formed by modifying the stitch 
structure, stitch length, yarn feed, or by other conventional methods. 
The outer relatively less elastic sleeve desirably includes first and 
second pocket access openings. In this way, a pulsatile bladder can be 
positioned within the pocket region between the inner and outer sleeves by 
inserting it through one of the openings, while the second opening can 
allow the exit of tubing typically associated with such bladders. In a 
preferred form of the invention, the bladder insertion opening is located 
proximate the upper end of the outer sleeve, while the tubing opening is 
relatively smaller than the insertion opening and is located proximate the 
lower end of the outer sleeve. One or more transitional courses desirably 
join the lower ends of the inner and outer sleeves; these courses are 
preferably made from a fusible yarn, which upon heating, fuses together 
and further stabilizes this juncture of the inner and outer sleeves. 
A preferred method of constructing a PAE stocking according to the instant 
invention involves knitting at least one course of transfer stitches on a 
first needle bed of a circular knitting machine, and knitting a second 
series of courses on the opposite needle bed of the knitting machine for a 
predetermined number of courses. At a predetermined position in that 
section of courses, a small number of the needles on the bed are taken out 
of action for a few courses to form a small number of held stitches, which 
form a small opening in the tubular fabric. All of the needles are then 
brought back into action and another elongate tubular section is knit. At 
a second predetermined position on that section of courses, a number of 
needles are again taken out of action for several courses to form a series 
of held stitches which form a second opening in the tubular fabric. The 
needles are again brought into action as the machine continues knitting a 
tubular structure. At a predetermined position, the knitting process is 
desirably modified to form a region having a greater amount of elasticity 
than the previously produced tubular structure (e.g. by inlaying an 
elastic yarn, changing the stitch structure, or the like.) This region of 
greater elasticity desirably forms an upper section of the outer sleeve 
and the inner sleeve of the stocking structure. Once the desired number of 
courses have been knit to form the inner sleeve, the original series of 
transfer stitches is transferred from the first needle bed to the other 
needle bed to join the inner and outer layers together at their respective 
lower ends. 
A small number of courses are desirably then knit to form a transitional 
region, to which a band or foot portion can then be knit. In a 
particularly preferred form of the invention, at least a portion of the 
transitional stitches include a fusible yarn (e.g. a heat fusible yarn.) 
In this way, the finished stocking can be heated to fuse the fusible yarn, 
which melds with the other yarns in the transitional region to provide a 
reinforced region at the juncture of the inner and outer sleeves. This 
reinforced region serves to increase stocking durability and reduce the 
incidence of raveling which can occur following repeated launderings. A 
heat fusible yarn is particularly preferred for use in stockings which are 
adapted to be scoured after production, as the scouring process itself can 
serve to fuse the fusible yarn without the need for additional production 
steps.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will now be described more fully hereinafter with 
reference to the accompanying drawings, in which a preferred embodiment of 
the invention is shown. This invention may, however, be embodied in many 
different forms and should not be construed as limited to the embodiments 
set forth herein; rather, this embodiment is provided so that this 
disclosure will be thorough and complete and will fully convey the scope 
of the invention to those skilled in the art. Like numbers refer to like 
elements throughout. 
With reference to the attached drawings, FIG. 1 illustrates one embodiment 
of a stocking according to the invention, and FIG. 2 is a cross-sectional 
view of the stocking shown in FIG. 1, as it appears prior to insertion of 
a pulsatile bladder, and FIG. 3 shows a cross-sectional view of an 
embodiment like that of FIGS. 1 and 2, as it would appear with an attached 
foot portion and a pulsatile bladder positioned within the pocket. The 
stocking, shown generally at 10, desirably includes inner 12 and outer 14 
tubular sleeves which are adapted to extend along the length of a wearer's 
limb (e.g. the calf of the leg). The inner and outer sleeves 12, 14 are 
desirably secured together along their upper and lower ends to form a 
hollow pocket 20 therebetween. In a preferred form of the invention, the 
inner and outer sleeves 12, 14 are integrally knit together so as to 
require no further manufacturing steps, in a manner discussed further 
herein. 
The inner sleeve 12 is desirably knit so as to be more elastic than the 
outer sleeve 14, so that it can fit closely and snugly around a wearer's 
limb. In a preferred form of the invention, the inner sleeve 12 is knit so 
that the degree of compression is graduated along the sleeve length to 
conform to the contours of a wearer's limb. This can be done using 
conventional methods such as feeding or inlaying varying amounts of 
elastic material, varying the stitch length or structure, or the like. In 
a particularly preferred form of the invention, the same knit stitch 
structure is used on the inner and outer sleeves 12, 14, but an elastic 
yarn such as spandex is laid into the courses forming the inner sleeve. 
The outer relatively less elastic sleeve 14 desirably includes a relatively 
small upper section 14a which has a greater elasticity than the major 
portion 14b of the outer sleeve. In this way, the relatively more elastic 
upper section 14a can assist in maintaining the stocking in its desired 
position on the wearer's body. The outer sleeve 14 also desirably includes 
a first opening 18 proximate its upper end and a second relatively smaller 
opening 20 proximate its lower end. In this way, a pulsatile bladder 22 
can be inserted through the relatively larger first opening 18 into the 
pocket 16 between the inner and outer layers, and the tubing 24 which 
typically extends from such a bladder can extend outwardly through the 
second opening 20. Further, because the outer layer 14 is less elastic 
than the inner layer 12, the tendency for the bladder 22 to be pressed 
uncomfortably against a wearer's limb by the stocking 10 is reduced. 
Additionally, because the pocket 16 formed between the inner and outer 
tubular layers 12, 14, desirably extends continuously around the entire 
circumference of the stocking 10, the position of the bladder 22 on the 
wearer's leg can be adjusted as desired so that it can be positioned at 
virtually any location about the circumference of a wearer's limb. 
The inner and outer layers 12, 14 are desirably secured together proximate 
their lower ends, with a number of courses of transitional stitches 26 
extending downwardly from the juncture of the inner and outer layers. The 
stocking 10 can terminate in a turned welt 28, as illustrated, or a 
partial or full foot portion 30 can be knit thereto. 
The knitting process, in one embodiment of the invention, can be performed 
as follows, with reference to FIG. 2. A first course or series of courses 
32 (i.e., the transfer stitches) can be knit on one of the sets of needles 
on a circular knitting machine, e.g., the dial needles. A second series of 
courses is then knit on the opposite set of needles (e.g., the cylinder 
needles) for a predetermined, relatively small length, which will form the 
lower end section of the outer sleeve 14. A number of stitches are held 
for a set number of courses, e.g., by taking a number of needles out of 
action, to form the small opening 20. The machine continues knitting, with 
the held needles being put back into service, to form a tubular body which 
forms a major portion of the length of the outer sleeve 14. At a 
preselected point, a number of needles are again taken out of commission 
for a number of courses to form the larger opening 18. By forming the 
first and second openings in this way, further finishing of them is not 
required as they do not have a tendency to ravel. 
The machine continues knitting to form the upper portion 14a of the outer 
sleeve 14, and preferably the structure of this portion is modified to 
render it more elastic than the major portion 14b of the outer sleeve. In 
a particularly preferred method, an elastic yarn such as spandex is laid 
in along this upper portion to assist in the stocking's securement about a 
wearer's limb. The elastic yarn continues to be laid in as the machine 
continues knitting a tubular body which forms the stocking inner sleeve 
12. The inner sleeve 12 is knit such that it provides graduated 
compression, in order to form a stocking 10 which accommodates the curved 
shape of a wearer's leg. 
Once the desired number of courses have been knit to form the inner sleeve 
12, the original series of stitches 32 (i.e., the transfer stitches) is 
transferred from the dial needles to the cylinder needles to join the 
inner and outer sleeves 12, 14 together. A small number of courses are 
then subsequently knit to form transitional region 26, to which is then 
knitted a band 28 in the form of a turned welt. As stated previously, the 
stocking could include a partial or full foot covering portion such as 
that illustrated at 30 in FIG. 3 in addition to or instead of an elastic 
band 28, as illustrated in FIG. 2. 
The stocking 10 thus comes off the machine in finished form. To conform 
with medical guidelines, the stocking 10 is desirably scoured for 
sterility purposes. In one form of the invention, a course or two 
proximate the junctures of the transitional stitches with the sleeve lower 
ends and/or the band 28 can be knit from a fusible yarn. In this way, when 
the invention is scoured, the heat from the scouring process fuses the 
yarns together to make a high strength connection between the courses 
which can reduce the incidence of raveling and juncture weakening. It is 
noted that the method can be reversed such that the transfer stitches are 
knit on the cylinder rather than the dial needle bed of the machine, or 
the knitting order can be modified, within the scope of the present 
invention, as will be appreciated by those having ordinary skill in the 
art. 
In the drawings and the specification, there has been set forth preferred 
embodiments of the invention and, although specific terms are employed, 
the terms are used in a generic and descriptive sense only and not for the 
purpose of limitation, the scope of the invention being set forth in the 
following claims.