U.S. patent number 3,775,793 [Application Number 05/218,623] was granted by the patent office on 1973-12-04 for shoe covering apparatus.
This patent grant is currently assigned to Allen S. Chen. Invention is credited to Roger M. Casavant, Wesley S. Larson, Richard L. Panicci.
United States Patent |
3,775,793 |
Casavant , et al. |
December 4, 1973 |
SHOE COVERING APPARATUS
Abstract
Apparatus for covering shoes on the feet of a wearer with a
protective sanitary shoe wrapper formed of heat-shrinkable material
is disclosed, wherein individual shoe wrappers are positioned at a
heat-shrink station in an open configuration to receive and enclose
a shoe on the foot of a wearer; after the insertion of the shoe,
heat is applied to the wrapper to heat-shrink it and conform it to
the shoe.
Inventors: |
Casavant; Roger M. (Enfield,
CT), Larson; Wesley S. (Enfield, CT), Panicci; Richard
L. (Westfield, MA) |
Assignee: |
Chen; Allen S. (Belleville,
MI)
|
Family
ID: |
22815819 |
Appl.
No.: |
05/218,623 |
Filed: |
January 17, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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84327 |
Oct 27, 1970 |
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Current U.S.
Class: |
12/1R |
Current CPC
Class: |
A43D
25/18 (20130101); A43B 3/163 (20130101); A43D
11/003 (20130101) |
Current International
Class: |
A43D
25/18 (20060101); A43D 11/00 (20060101); A43D
25/00 (20060101); A43B 3/16 (20060101); A43d () |
Field of
Search: |
;12/1R,1A,142R
;36/1,72R,72C |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lawson; Patrick D.
Parent Case Text
This is a continuation of U.S. Pat. Ser. No. 84327, filed Oct. 27,
1970, now abandoned.
Claims
What is claimed is:
1. A device for covering a shoe on the foot of a wearer with a
protective wrapper, comprising means for positioning said wrapper
for insertion of said shoe and foot therein and means for heat
shrinking said wrapper about said shoe at a heat shrink station in
said device after insertion of said shoe in the wrapper, whereby
said wrapper conforms to said shoe.
2. A device as in claim 1 including a storage station adapted to
contain a supply of said wrappers.
3. A device as in claim 2 wherein said positioning means includes
means for moving individual shoe wrappers from said storage station
to said heat shrink station.
4. A device as in claim 3 wherein said wrappers are fully formed
oversized overshoes having an access opening for said shoe in the
upper portion thereof and said positioning means includes means for
holding said overshoe in its open configuration.
5. A device as in claim 4 wherein said holding means comprises
means for blowing air through said access opening into said
overshoe.
6. A device as in claim 5 wherein said heat shrinking means
comprises means for supplying warm air to the surface of said
wrapper.
7. A device as in claim 3 wherein said wrappers are secured to a
plurality of guide strips and said positioning means includes means
for drawing said guide strips and said wrappers to said heat shrink
station from said storage station.
8. A device as in claim 7 including a supply roll rotatably mounted
at said storage station, said wrappers and said strips being wound
on said supply roll, whereby individual wrappers are sequentially
drawn from said roll by said drawing means.
9. A device as in claim 8 wherein said strips are secured to said
wrappers by heat sensitive material, whereby said strips are
released from said wrappers when said wrappers are shrunk by said
heat shrinking means.
10. A device as in claim 7 wherein said wrappers are formed with a
toe portion, a sole portion, and spaced side portions rearwardly of
said toe portions, said side portions forming said access opening
in the upper portions and heel of said wrapper, and said drawing
means including means cooperating with said strips to hold said
wrapper in an open configuration for insertion of a shoe through
said opening.
11. A device as in claim 10 including means for sealing said open
sides after insertion of said shoe therein.
12. A device as in claim 10 including means for sensing the size of
said shoe after insertion in said wrapper and means responsive to
said sensing means for sealing said open sides adjacent said shoe
to enclose said shoe prior to heat shrinking thereof.
13. A device as in claim 10 wherein said heat sealing means
comprises a pair of heat sealing bars adapted to be moved towards
each other and to engage said open sides therebetween to seal said
sides together.
14. The device as in claim 13 including means for severing said
sides rearwardly of said shoe and said heat seal to remove excess
portions thereof from said wrapper.
15. The device as in claim 11 wherein said heat shrinking means
comprises means for supplying warm air to the surface of said
wrapper.
16. The device as in claim 12 including means for shielding the
wearer's leg from said warm air.
17. The device as in claim 12 including means for shielding said
storage station from said warm air.
18. The device as in claim 11 wherein said means for heat shrinking
said wrapper comprises means for directing infrared radiation
towards said shoes.
19. A device for covering the shoe on the foot of a wearer with a
protective wrapper, said device comprising, a frame, an operating
station located in said frame for receiving a shoe on the foot of a
wearer covered by an oversized heat shrinkable protective wrapper,
and means at said operating station for heat shrinking said
oversized wrapper about said shoe, whereby said wrapper shrinks to
conform to said shoe; said heat shrinking means comprising means
for supplying warm air to the surface of said wrapper; and means
for shielding the wearer's leg from said warm air.
Description
This invention relates generally to heat-shrinkable overshoes and
to a method of applying heat-shrinkable overshoes to shoes while
the shoes are being worn.
Disposable overshoes have been proposed in the past for use in
various facilities in which sterile conditions must be maintained,
e.g., for covering the shoes of physicians or other personnel
working in operating or clean room facilities. Such overshoes are
often utilized in hospital operating rooms where it is necessary to
prevent contamination of the atmosphere and floor from bacteria
carried on street shoes, thereby to avoid infection of the patient.
Further, it is frequently necessary to maintain extremely clean
conditions in industrial and commericial installations during
production processes. This is particularly necessary in the
aerospace and electronics inductries, where delicate electronic
components must often by protected from chemical and physicial
contaminants, minute particles of dirt, fine metal particles,
etc.
The sanitary overshoes which have previously been proposed for use
in these areas have been generally formed from a variety of
materials, including paper, natural synthetic fibers, and plastic
films. These overshoes have also been formed in a variety of
manners, as by gluing, sewing, or heat-sealing the various parts to
form completed shoe coverings. These coverings are generally
provided with elastic tops, tie-strings, snap fasteners, and the
like to secure them to the shoe and to facilitate later removal
thereof.
While these prior art boots have been helpful in maintaining
sanitary conditions in hospital operating rooms and other clean
rooms, they have numerous disadvantages. Thus, they are generally
cumbersome in appearance and are difficult to apply and remove.
Moreover, the prior art boots are relatively expensive to produce
and do not offer complete sanitary protection for hospital use.
They are not fully sealed to the shoe, but rather are generally
loose-fitting with numerous folds and openings through which
bacteria and contaminants may escape to the atmosphere or floor of
the operating room. Due to their expense, many of these boots must
be reused, thereby requiring time consuming and costly
sterilization procedures which, it is noted, are generally not
fully satisfactory. Finally, due to their cumbersome size and
bag-like character, the prior art boots are not only uncomfortable
and untidy but they are also difficult to walk in. Thus, for
example, such boots may hinder the mobility of the physician in the
operating room.
Also, there is a need for cheap disposable protective foot
coverings to protect the shoes in unexpected inclement weather.
Such coverings could conveniently be dispensed from coin-operated
machines in public places such as airports, railroad stations, and
the like, for example.
Accordingly, it is an object of the present invention to provide a
method and apparatus for protecting the shoes, particularly those
of clean room and operating room personnel, with a shoe wrapper
which is disposable after a single use.
Another object of the invention is to provide a relatively simple
and inexpensive method of covering a shoe with a sanitary
wrapper.
A still further object of the invention is to provide a method and
apparatus for protecting a shoe with a sanitary wrapper by
automatic application of the wrapper tightly to the shoe to
maintain a good appearance conforming to the shoe, thereby to
facilitate walking.
Yet another object of the invention is to provide a method of
covering either the left or the right shoe of the wearer with a
single undifferentiated wrapping.
In accordance with an aspect of this invention, a method and
apparatus for protecting a shoe with a sanitary shoe wrapper are
disclosed wherein a supply of wrappers, formed of heat-shrinkable
material, is provided and each individual wrapper is positioned in
a partially open configuration to receive and enclose a shoe on the
wearer's foot. After insertion of the foot within the wrapper, a
supply of heat such as a current of warm air, is directed over the
wrapper to shrink the material on the shoe so that the wrapper
conforms to the shoe and fully encloses the same.
For use in operating rooms or other places where explosive
atmospheres may be encountered, each of the shoe wrappers may be
provided with a conductive strip secured to the sole of the wrapper
and adapted to contact the leg of the wearer at its other end,
thereby to prevent discharges of static electricity between the
foot of the wearer and the floor.
The above, and other objects, features and advantages of this
invention will be apparent in the following detailed description of
illustrative embodiments of the invention which are to be read in
connection with the accompanying drawings wherein;
FIG. 1 is a perspective view of a device, according to an
embodiment of the present invention, adapted to heat-shrink a
plastic overshoe or boot onto the shoe of a wearer;
FIG. 2 is a perspective view of a plastic overshoe or boot formed
in accordance with the present invention;
FIG. 3 is a perspective view of the boot shown in FIG. 2, sealed on
the foot of a wearer after the heat-shrink operation;
FIG. 4 is a side view, in section, of the device of FIG. 1, taken
along line 4--4 of FIG. 1;
FIG. 5 is a partial front view, in section, taken along line 5--5
of FIG. 4 showing the left half of the device of FIG. 1;
FIG. 6 is a plan view of a portion of the device taken along line
6--6 of FIG. 5, with the leg shields removed;
FIG. 7 is a perspective view of another embodiment of the present
invention;
FIG. 8 is a perspective view of an overshoe formed for use in the
embodiment of the invention shown in FIG. 7;
FIG. 9 is a side view, in section, taken along line 9--9 of FIG.
7;
FIG. 10 is a plan view of a portion of the embodiment of the
invention shown in FIG. 7, taken along line 10--10 of FIG. 9;
and
FIG. 11 is a side view, in section, taken along line 11--11 of FIG.
9.
Referring to the drawings in detail, FIG. 1 shows device 10, of a
type adapted to carry out the method of the present invention,
generally comprising housing 12 having a storage section 14 and
plurality 16 of heat-shrink stations where shoe wrappers 18 are
presented beneath leg shields 20 for heat-shrinking about shoes on
the feet of a wearer.
The wrappers placed on the foot of a wearer in this embodiment of
the invention are shown in FIG. 2 and are formed of a sheet of
material, e.g., a film of a plastic such as polyethylene or a vinyl
copolymer, which is adapted to be heat-shrunk at relatively low
temperatures. The wrapper is pre-formed as an oversized boot or
overshoe having upper access opening 22 and plurality 24 of rear
edges which, as more fully described hereinafter, are held in an
open configuration at the heat-shrink station to permit insertion
of a shoe on the foot of a wearer prior to the heat-shrink
operation. Wrapper 18 is shaped generally with rounded front end or
toe portion 26 to conform generally to the shape of a shoe,
conveniently by heat-sealing the edges thereof, so that on
shrinking the wrapper will more readily conform to the general
configuration of a shoe.
Strip 28 of conductive plastic material, such as a polyethylene
impregnated with carbon black or metallic particles is heat-sealed
to sole 30 of the wrapper at end 32 thereof, and is looped about
the exterior of the wrapper with second end 34 positioned within
access opening 22. After application of the overshoe, end 34 of
strip 28 is inserted in shoe 36 to touch the ankle of the wearer
and provide a ground connection between the body and the floor,
thus to prevent discharges of static electricity therebetween. It
is contemplated that strip 28 may be tucked into the arched section
of the foot outside the sock so that strip 28 may not touch the
ankle but will provide an electrical connection to the body.
Alternatively, it is contemplated that wrapper 18 itself may be
completly formed of a conductive plastic material, in lieu of the
use of strip 28.
After the heat-shrinking operation, as performed by the device 10
and described hereinafter, wrapper 18 conforms to shoe 36 on the
foot of a wearer, as seen in FIG. 3, to provide a pleasant
appearing, comfortable and compact shoe covering which is sealed
tightly to the shoe to prevent escape of bacteria and other
contaminants from the shoe to the ambient atmosphere, e.g., to a
hospital operating room of a clean room environment in which the
wearer is working.
While the material used to form the shoe coverings in the preferred
embodiments of this invention is impervious to air so as to prevent
escape of bacteria, etc., from the shoes, it is contemplated that
the shoe covering may also be used in environments and in
applications wherein such a high degree of sterility is not
required. For example, overshoes of the character described could
be used by window dressers or could also be used as foul weather
overshoes. In these situations the wrapper material could be made
air permeable by extremely small perforations in the material to
permit ventilation of the foot and shoe. These perforations would
however be positioned or dimensioned so as to prevent water from
penetrating the wrapper and entering the shoe.
If a material which shrinks anisotropically is employed as the
heat-shrinkable film in forming boot 18, the material is "aligned"
in the longitudinal direction of the boot, so that the boot will
shrink during the heat-shrink operation more in the direction of
the length of the foot than in the direction of its width. By this
construction the material is not tightened to a substantial extent
adjacent edge 38 of the heel on shoe 36 so as to fracture or tear
the material during walking. It is contemplated also that the
material may be provided with a reinforcing strip of material at
those portions on sole 30 thereof adjacent the heel to strengthen
the material and avoid tearing during use.
To facilitate removal of the overshoe, tear strip or string 40 is
embedded in the material forming wrapper 18 and is provided with
loose end 42. Upon completion of use of the heat shrunk overshoe,
and 42 of strip 40 is grasped by the wearer, and pulled downwardly
to tear the material. The overshoe is thereafter readily peeled
from the shoe. It is also contemplated, that where a conductive
strip 28 is utilized, this strip may be heat sealed along a major
portion thereof to the surface of wrapper 18 so that end 34 thereof
may be grasped, upon completion of the use of the overshoe, to tear
the material and permit its removal.
Wrappers 18 are formed as individual members and are wound on roll
44 rotatably mounted in housing section 14. The wrappers are
interconnected by pairs of strings or plastic strips 46, 46a,
secured to the wrappers by a heat-sensitive adhesive (e.g. glue or
wax) to form an integral roll of boots. As seen in FIGS. 5 and 6,
the pair of strips 46 are secured to upper surface or sides 48 of
wrapper 18, and pair of strips 46a are secured to sole 30 of the
wrapper. While in the preferred embodiment, wrappers 18 are
individually formed and separately secured to strips 46, 46a, it is
contemplated that the wrappers also can be provided as an integral
roll wherein the front and rear edges of adjacent wrappers are
connected by a perforated strip which is readily torn on completion
of the heat shrink operation by a slight foot movement.
The ends of strips 46 are respectively guided over rollers 52
mounted in leg shield 20 as shown in FIGS. 1 and 5. From rollers 52
strips 46 extend through elongated aperture 54 in support surface
or platform 56 and are secured to roll 58. Strips 46a extend along
the surface of platform 56 through apertures 60 therein and are
respectively secured to takeup pulleys 62. The latter are fixed to
common shaft 64 adapted to be simultaneously rotated with roll 58
by motor 66 mounted below platform 56 in housing 12. Motor 66 has
drive shaft 67 extending therefrom on which drive pulley 68 is
secured. Pulley 68 is connected by belt 70 to pulley 72 mounted at
one end of roll 58. Second pulley 74 mounted on roll 58 drives
pulley 76 on shaft 64 through belt 78, so that while motor 66 is
operating roll 58 and pulleys 62 are simultaneously rotated to draw
wrappers 18 from roll 44 through aperture 57 in platform 56 to heat
shrink station 16.
Initially, overshoe heat shrink device 10 is prepared for operation
by securing strips 46 and 46a to roll 58 and pulleys 62, as
described above, with the first wrapper 18 on roll 44 in position
at heat shrink station 16. As seen in FIGS. 1 and 4, wrapper 18 is
held at station 16 by pulleys 52 and 62 with access opening 22 and
edges 24 in an open configuration permitting insertion of the
wearer's foot and shoe within the wrapper prior to the heat shrink
operation.
In order to close the opened rear end of boot 18 after the wearer
has inserted his foot therein, a pair of jaws 80 are provided which
are adapted to heat-seal sides 48 of wrapper 18 together adjacent
the heel of shoe 36. Jaws 80 are formed as individual bars
pivotally mounted by pins 82 on a transport plate 84 slidably
mounted in recess 86 of platform 56. Recess 86 is formed by pair 88
of longitudinally extending parallel stepped ledges having first
stepped portions 90 which receive the longitudinal edges of plate
84 and define aperture 92 therebetween. Jaws 80 extend along the
upper surface of plate 84 and into second stepped portions 94 of
ledges 88 whereby bars 80 and plate 84 are located below the upper
surface of platform 56 so that no obstruction is formed on the
platform.
In order to provide a more pleasing appearance of the wrapper after
heat shrinking, it is desirable to heat-seal sides 48 together
adjacent the heel of shoe 36 prior to the heat shrinking operation
since wrappers 18 are supplied in a uniform size being somewhat
larger than a standard size 13 shoe. Thus plate 84 is mounted for
sliding movement longitudinally on ledges 90 to provide an
adjustment for the position of heat-sealing jaws 80 thereby to
closely secure wrappers 18 to various sized shoes so that the
overshoe, when shrunk, conforms tightly to the shoe itself. To move
plate 84 and, thus, bars 80 to a position adjacent the heel of shoe
36, rack 96 is provided on lower surface 98 of plate 84 and engaged
by spur gear 100. The latter is driven by motor 102 mounted on
lower surface 104 of platform 56.
When the wearer inserts his foot within wrapper 18, he engages
pressure switch 106 mounted on platform 56 adjacent the ball of his
foot, which switch activates motor 102 to drive gear 100 and
thereby move rack 96 and plate 84 toward the heel of his foot.
Contact or microswitch 108 is provided immediately in front of bars
80 on the upper surface 110 of plate 84 to engage the heel of the
shoe 36 as plate 84 is moved beneath the shoe. Accordingly, when
plate 84 is moved towards shoe 36, i.e., towards the left in FIG.
4, a sufficient distance to engage switch 108 with the heel of the
foot, switch 108 deactivates motor 102 to stop movement of plate 84
and simultaneously activates motor 112. Motor 112 pivots bars 80
about pins 82 to move the bars to a vertical clamping position as
seen in FIG. 5. It is noted that while only one of the heat
shrinking stations 16 is illustrated in FIGS. 5 and 6, the other
station is similarly constructed and operates in the same manner as
the described station.
Referring again to FIG. 5, it is seen that inner ends 114 of bars
80, adjacent pivots 82 are formed with interengaging quadrant gears
116. One of these gears is provided with an integral crank arm 118
which is pivotally connected, by link 119 to crank 120 fixed to
drive shaft 121 of motor 112. As motor 112 is operated, crank arm
120, and thus crank arm 118, is moved downwardly, thereby to pivot
the bars 80 to the vertical position shown phantom. As bars 80 move
to the vertical position, they engage sides 48 of wrapper 18 and
move the sides towards each other and ultimately into contact with
each other when the bars are in their fully extended vertical
position.
A safety control device 101 is provided on plate 84 to prevent bars
80 from being raised in the event that the bars are blocked as for
example, by the heel of the foot. Control device 101 includes a
photoelectric cell pickup 103 mounted adjacent one edge 105 of
plate 84 and a light source 107 mounted adjacent opposite edge 109
which light source directs a beam of light towards pickup 103.
Pickup 103 is connected to a control circuit (not shown) which is
operative to prevent activation of motor 112 should the light from
source 107 be blocked. That is, if the heel of the foot is over
bars 80, thereby obstructing passage of light from source 103 to
pickup 107, the bars will not be pivoted by motor 112. In this
manner damage to the bars and gears 116 is avoided, as is any
possibility of injury to the foot.
Each bar 80 has mounted thereon resistance wire 122 which is
connected to impulse heating unit 124 for heating wires which is
connected to impulse heating unit 124 for heating wires 122. After
bars 122 are moved to their vertical position, unit 124 is
automatically and sequentially operated to heat wires 122 and seal
sides 48 together. After the heat sealing operation is completed,
which operation generally takes less than 5 seconds, motor 112 is
sequentially operated in reverse to permit bars 80 to return to
their horizontal position. Thereafter, heat, such as a draft of
warm air is supplied to heat shrink stations 16 to shrink the
plastic wrappers about the shoes.
Bars 80 are each provided with a second resistance wire 126
connected to an independent impulse heating unit (not shown) for
simultaneous heating with wires 122. Wires 126 are located on bars
80 rearwardly of wires 126 and may have either sharpened edges or
lie positioned so that they lie in overlapped relation when bars 80
are raised. In this manner wires 126 act as a cutter during the
heat sealing operation to cut any excess material rearwardly of the
heat seal. This excess material is thus separated from the main
body of the wrapper and is discharged from the device in a manner
more fully described hereinafter.
Shield 20, of housing 12, defines an air plenum chamber 128
adjacent each of the wrappers 18 at heat shrink station 16. Warm
air is supplied to the plenum chambers through apertures 130 formed
in platform 56 adjacent recess 86. Air is provided from an
electrically driven blower 132 which flows air over electrically
powered heating elements 134. The air, thus warmed, is thence
discharged through duct 136 to plenum chambers 128 formed above
platform 56, as shown in FIG. 4. The air thus supplied is
discharged through apertures 130 into plenum chambers 128 and flows
about wrappers 18. The heat supplied by the elements 134 is
sufficient to warm the air to a high enough temperature to permit
shrinking of the copolymer material of which the wrapper is formed.
Shield 20, limits discharge of warm air upwardly from the plenum
chambers to protect the trousers and the leg from the warm air.
However, it is noted that the temperature of this air is
sufficiently low so that sealing of the wrapper on the foot of the
wearer is performed with complete safety and the entire operation
is performed at relatively comfortable temperatures for the short
period of time which the shrinking process takes. Blower 132 and
heating elements 134 are controlled by a conventional timing
circuit and after these elements have been in operation for a
period of time adequate to shrink the wrapper to the configuration
shown in FIG. 3, they are automatically shut off and the foot may
be removed from the device. A temperature sensitive switch 137 is
provided in the circuit controlling blower 132 and heating elements
134, and this switch is located on platform 56 adjacent wrappers 18
(see FIG. 6). Switch 137 is adapted to shut off blower 132 and
heating elements 134 in the event that there is a malfunction in
the device which causes them to continue in operation beyond the
predetermined period. Thus, should the temperature within plenum
chambers 128 rise above a predetermined level, the hot air will be
immediately shut off. Further, in the preferred embodiment, heating
elements 134 and blower 132 shut off sequentially, with elements
134 shutting off first, so that a flow of relatively cool air is
supplied to plenum chambers 128 to carry heat away from the heated
wrappers and "set" the plastic material. Alternatively, a separate
and independent blower may be provided for this purpose.
During the heat shrinking operation, the remaining wrappers on roll
44 are protected from the warm air by housing section 14. The
volume of air entering this section through supply slot 57 in
platform 56 is inadequate to damage these wrappers. Moreover, while
the heat shrinking operation has been described using a supply of
warm air, it is contemplated that other known heat shrinking
methods may be utilized. In particular, it is forseen that sources
of infrared radiation may be provided to shrink wrappers 18.
As mentioned above, strips 46 and 46a are secured to wrappers 18 by
heat-sensitive adhesive. Thus these strips are released from the
wrappers during the heat shrinking operation, since the adhesive
releases or separates under the influence of the warm air supplied
from blower 132 and heater 134. The strips are formed of
non-heat-shrinkable material and are in no way damaged by the
heat-shrinking process. However, strips 46 are secured to wrappers
18 adjacent rear edges 24, as for example at points 140 which are
sufficiently remote from shoe 36 and apertures 130 so that that
connection of the wrapper with the strips at this point is not
released. Thus, on completion of the heat shrinking operation, when
the wearer removes his foot from the device, strips 46 remain
secured to the excess material removed from the boot by heat
sealing bars 80 and their cutting edges 126.
Release of pressure on switch 106, by removal of the wearer's foot,
activates motor 66, after a suitable time delay, to rotate roll 58
and pulley 62. In this manner strips 46a are wound on pulleys 62
and strips 46, along with the excess or waste portion of the prior
boot are drawn through aperture 54 in platform 56 onto roll 58.
Motor 66 is controlled by a conventional timing circuit and
continues in operation for a predetermined period of time adequate
to properly position the next wrapper 18 on roll 44 at heat shrink
station 16. Thereafter the cycle is restarted by subsequent
activation of switch 106. It is noted that the specific electronic
circuitry utilized in overshoe heat shrink device 10 to control the
various components thereof forms no part of the present invention,
and is not described in detail. The sequential steps of the present
invention may be controlled in numerous manners, as will be evident
to those skilled in the art.
After use of the overshoe is completed, wrapper 18 is conveniently
removed from the foot of the wearer by tear strip 40. Free end 42
of string 40 is grasped and pulled downwardly to tear the
relatively thin plastic material and free wrapper 18 from shoe 36.
It is noted that while the material is sufficiently thin to be torn
by narrow string 40, the material is also sufficiently strong and
durable to withstand normal usage and will not tear of its own
accord. As mentioned above, it is contemplated that conductive
strip 28 may be heat-sealed along a thin line to the sides 48 of
wrapper 18 so that it also may be used as a tear strip.
Referring now to FIG. 7, there is illustrated an embodiment of the
present invention which is adapted to heat shrink pre-formed
overshoes on a shoe on the foot of a wearer. As seen therein,
overshoe heat shrink device 150 includes housing 152 having storage
section 154 and pair 156 of heat shrink stations. Leg shields 158
are provided at stations 156, and correspond substantially to
shields 20 of the previously described embodiment. In this
embodiment, fully formed oversized wrappers 160 are provided, as
seen in FIG. 8. Wrappers 160 have enlarged access opening 162 at
the upper surface thereof through which the foot of the wearer is
inserted.
Initially, wrappers 160 are in position at heat shrink stations 156
and the wrappers are opened to a limited extent, from their prior
folded configuration, because of their own natural resiliency. When
the wearer desires to place the wrappers upon his feet, he steps
onto the forward portion of platform 164, including pads 166, and
thereby activates pressure switches 168 mounted below the pads.
Switch 168 control a blower or source of suction 170 which is
connected by a pair of ducts 172 to plenum chambers 174. Chambers
174 are mounted on the lower surface 176 of platform 164 at
opposite sides of heat shrink stations 156 and communicate with
plenum chamber 177 formed by shield 158 about station 156 through
apertures 180 in platform 164. Suction source 170 creates a low
pressure atmosphere in plenum chambers 177 by drawing air from the
chamber through chamber 174 and ducts 172. Simultaneously, source
170 supplies this air to jets 182 having nozzles 184 directed into
access opening 162 to partially inflate the overshoe. Thus, the
combination of the low pressure within plenum chamber 177 and the
force of the jets of air discharged from source 170 to jet nozzles
184 into access opening 162 of wrappers 160 opens the wrappers to
facilitate insertion of the shoe therein.
To further facilitate insertion of shoe 36 within wrappers 160 and
to enlarge the access opening presented to the shoe for insertion,
hold-down mechanism 186 is provided for the heel of the wrapper.
Hold-down mechanism 186 includes a pair of plenum chambers or
suction cups 188, each of which is pivotally mounted by arms 189 on
platform 164 adjacent opposite sides of heel 190 of wrapper 160.
Arms 189 each include a rigid lever 192, which levers are pivotally
connected respectively, by links 192, which levers are pivotally
connected respectively, by links 194 to solenoids 196 for operative
control of the position of cups 188. Suction cups 188 include a
perforated face 198 which encloses a chamber 200 connected by
flexible conduit 191 to source of suction 170. Activation of
pressure switch 168 simultaneously activates source of suction 170
and solenoid 196 so that arm 189 is first pivoted downwardly to
engage face 198 of cup 188 with heel 190 of wrapper 160. Since
plenum chamber 200 is connected to source of suction 170, a low
pressure area is produced in chamber 200 which causes heel 190 to
be secured to face 198. After cups 188 reach their lowermost
position, solenoid 196 is operated in reverse to raise the cups and
the heel 190 in conjunction therewith to enlarge the access opening
in the wrapper. In FIG. 7, suction cups 188 in each of heat shrink
stations 156 are respectively shown in their raised and lowered
positions for clarity in understanding their operation.
After the physician's feet are inserted in wrappers 160, they are
supported at heat shrink stations 156 by wrapper transport plates
202 whose principal function is described more fully hereinafter.
Plates 202 are mounted for sliding movement in recesses 204 on
longitudinally extending ledges 206 adjacent the sides thereof. The
pressure of the wearer's weight on plate 202 activates
pressure-sensitive switch 208 positioned on ledge 206 which
deactivates suction source 170. Simultaneously, blower 210 and
heating elements 212 are activated, which elements supply warm air
to plenum chamber 174. Blower 210 blows air over heating elements
212 and supplies the warmed air through duct 214 to plenum chamber
174 wherein the warm air is discharged through apertures 180 to
plenum chamber 177. The air is thereby flowed over the surface of
heat shrink wrapper 160 to shrink the material of which the wrapper
is made and conform the wrapper to the shoe. As in the prior
embodiment, blower 210 and heating element 212 are controlled by a
conventional timing circuit so that after a period of time,
adequate to shrink the material forming wrappers 160, the blower
and heating elements are sequentially shut off so that a flow of
relatively cool air is supplied to set the molten plastic. When the
blower shuts off, the wearer may remove his foot from the chamber.
A thermal shut off switch or control 137 may also be provided in
the circuit for blower 210 and heater 212 to shut off the system in
the event of a malfunction which causes the temperature in plenum
chamber 177 to rise above a predetermined level. As in the prior
embodiment, the particular electronic circuitry utilized in
conjunction with the present invention to perform the various
operations thereof are within the skill of the ordinary artisan and
illustration of specific circuits is omitted.
When the wearer's foot is removed from heat shrink station 156,
pressure on switch 208 is released and, after a suitable time
delay, transport plate 202 is operated to move a wrapper 160 from
storage station 213 within housing section 154. Wrappers 160 are
supplied to storage station 213 in stacks 211 seated on movable
platforms 215. Platforms 215 are slidably mounted on ledge 206 and
associated respectively with each of the heat shrink stations
156.
Each platform 215 is mounted on a pair of rods 217 secured to the
rear wall 216 of housing 152. Each of the rods 217 is provided with
a compression spring 219 surrounding the rod, which springs urge
platform 215 into position beneath the stack of wrappers.
Release of switch 208 activates air cylinder 218 which is adapted
to reciprocate transport plate 202 from heat shrink station 156,
along ledges 206, to storage station 213. As plate 202 is moved
towards plate 215, plate 202 engages plate 215 and moves the latter
from beneath stack 211 and towards wall 216 while stack 211 is held
stationary by baffle 230. At the end of the stroke of piston 218,
the rearward end 221 of plate 215 is engaged with a switch 220.
Switch 220 activates a vacuum source 222 which decreases the
pressure beneath plate 202 to secure an individual wrapper to the
surface thereof. Plate 202 has plenum chamber 224 formed
therebeneath and connected by flexible conduit 226 to source of
suction 222. Chamber 224 is thus moved with plate 202 from heat
shrink station 156 to storage station 213. Cylinder 218 is then
operated in reverse to withdraw plate 202 and an individual wrapper
160, which is secured thereto by the suction force produced by
member 222 from station 213 back to heat shrink station 156. At the
same time, plate 215 is urged back to position beneath the stack
211 by springs 219 to maintain the remainder of the overshoes
within the stack and in position for subsequent operations.
In this embodiment of the present invention it is seen that there
is no waste, as a fully formed heat shrink boot is provided and
there is no excess cut off portions of the boot by heat sealing
jaws as in the prior embodiment. The material of the boots in this
embodiment of the invention is similarly aligned in the manner
earlier described so that the material shrinks more in the
direction of length than in width and thereby provides a relief
area adjacent the forward edge of the heel so that the material is
not damaged or torn by the heel during use.
For hospital use, each of the above-described embodiments of the
present invention can be incorporated into a console unit (not
shown) at which the physician may perform other procedures while
having the sanitary overshoes automatically applied to his feet.
For example, the console may contain a supply of surgical hats,
surgical masks, and gowns which the physician may put on during the
time in which the booting operation is taking place.
It is thus seen that a simple and relatively convenient sanitary
shoe wrapping is provided which is readily placed on the foot of
the wearer and which is neat and clean in appearance and
comfortable in use. Further, the overshoes of the present invention
are both for right and left feet, so that a single over-wrapper
will fit either foot and thus substantially reduce the cost of
manufacturing the wrappers. Moreover, the wrappers are relatively
inexpensive, thus disposable, and they are rapidly and conveniently
applied to the shoes of the wearer by the methods of the present
invention.
Although illustrative embodiments of the present invention have
been described herein with reference to the accompanying drawings,
it is to be understood that the invention is not limited to those
precise embodiments, and that various changes and modifications may
be effected therein by one skilled in the art without departing
from the scope or spirit of this invention.
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