US3694939A

US3694939A - Method of covering shoes

Info

Publication number: US3694939A
Application number: US84328A
Authority: US
Inventors: Allen Chen
Original assignee: LORTON LAB Ltd
Current assignee: LORTON LAB Ltd
Priority date: 1970-10-27
Filing date: 1970-10-27
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03

Abstract

A method 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 heatshrink it and conform it to the show.

Description

United States Patent 1151 3,694,939

Chen 51 Oct. 3, 1972 [54] METHOD OF COVERING SHOES 3,359,658 12/1967 Price ..36/9 R 72 I t z All Ch B 11 vi ,Mi h 3,419,929 1/1969 SHOW etal ..12/142R E 2 ti i N 3,525,110 8/1970 Batchelder et al. ..36/72 c ssrgnee: n ra nes, ew

York Primary Examiner-Patrick D. Lawson 22 Filed: Oct. 27, 1970 Arwrrwkcuflisi Morris & Safford [21] Appl. No.: 84,328 [57] ABSTRACT A method for covering shoes on the feet of a wearer [52] $8.8]. ..36/7.3, 36/72 C, 12/142R with a protective sanitary shoe wrapper formed of 2; i A43d 9/00 heat-shrinkable material is disclosed, wherein in- 1 e o c l l g g g dividual shoe wrappers are positioned at a heat-shrink I station in an open configuration to receive and en- 56] R f cud close a shoe on the foot of a wearer; after the insertion e erences of the shoe, heat is applied to the wrapper to heat- UNTED STATES PATENTS shrink it and conform it to the show.

2,648,854 8/1953 Otsuka ..36/72 C.

30 Claims, 11 Drawing Figures PATENTEDUBTIB I972 3,694,939

SHEET 1 BF 6 INVENTOR. uqlleiz C/zen/ ZQWM hi/22 I ATTOH METHOD OF COVERING SHOES 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 commercial installations during production processes. This is particularly necessary in the aerospace and electronics industries, where delicate electronic components must often be protected from chemical and physical 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, tiestrings, 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 wearers 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. 7

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 heatshrink 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 ofFIG. 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 heatshrink stations where shoe wrappers 18 are presented beneath leg shields 20 for heat-shrinking about shoe 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 be tucked into the arch 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 completely formed of a conductive plastic material, in lieu of the use of strip 28.

After the heat-shrinking operation, as performed by the device 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 or 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 heatshrink 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, end 42 of strip 40is 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 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 54in 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 take-up 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 wearers 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'ledges88 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 heatseal sides 48together 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 longitudinallyon 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 towards 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 1 14 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 in phantom. As bars 80 move to the vertical position, they engage sides 48 of wrapper 18 and moves 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 1 12. 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 122. After bars 80 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 S'seconds, motor 112 issequentially 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 be 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 stations 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 I 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. 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 foreseen 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 heatshrinking 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 wearers 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 the 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 in embodiment of the present invention which is adapted to heat shrink preformed overshoes on a shoe on the foot of a wearer. As seen therein, overshoe heat shrink device 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. Switches 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 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 solenoids 196 so that arm 189 is first pivoted downwardly to engage face 198 of cup 188 with heel 190 of wrapper 160. Since plenem 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 heat-shrink station 156 are respectively shown in their raised and lowered positions for clarity in understanding this operation.

After the physicians 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 wearers 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, 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 malfunction which causes the temperature in plenum chambers 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 wearers 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 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 the 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 ex-' ample, 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 also contemplated that such a console may contain a supply of heat shrinkable overshoes which may be manually applied to the physicians foot. The above-described apparatus may then be used to heat shrink the wrappers, or alternatively, the console may include a warm air blower which can be held manually and utilized to shrink the wrappers. I

It is thus seen that a sample and relatively convenient sanitary shoe wrapping is provided which is readily, placed on the foot of the wearer and which is neatand clean in appearance and comfortable in use. Further, the overshoes of the present invention are both for right and left feet, so that a singleoverwrapper 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.

What is claimed is:

l. The method of covering a shoe on the foot of a wearer with a protective wrapper, comprising the steps of positioning said wrapper for insertion of said shoe and foot therein, inserting said shoe and foot in the wrapper, and, after insertion of said shoe, heat shrinking said wrapper about said shoe, whereby said wrapper conforms to said shoe.

2. The method as in claim 1 wherein said wrapper is preformed, said method including the step of holding said wrapper in an open configuration for insertion of said shoe and foot therein.

3. The method as in claim 2 wherein said holding step includes the step of blowing air into said wrapper.

spaced relation to permit insertion of said shoe in said wrapper.

6. The method as in claim including the step of sealing said open wrapper sides after insertion of said shoe.

7. The method as in claim 6 wherein said sealing step comprises the step of heat sealing said sides.

8. The method as in claim 1 wherein said step of heat shrinking comprises the step of directing infrared radiation at said shoe and said wrapper.

9. The method as in claim 5 including the steps of sensing the size of said shoe after insertion in said wrapper and sealing said wrapper sides adjacent said shoe to enclose said shoe prior to said heat-shrinking step.

10. The method of claim 9 wherein said sealing step comprises the step of moving a pair of heat sealing jaws toward each other with said open sides therebetween.

l l. The method of claim 10 wherein said sensing step includes the step of moving said jaws to a position adjacent the heel of said shoe prior to said heat sealing step.

12. The method of claim 10 including the step of cutting off excess portions of said sides.

13. The method of claim 1 including the step of forming said wrapper with an electrically conductive strip to provide a ground contact between the body of the wearer and the floor.

14. The method of claim 13 including the step of heat sealing a portion of said strip to said wrapper along a relatively narrow band, whereby said strip comprises a tear strip for opening said wrapper after use.

15. The method of claim 13 including the step of forming a tear strip in said wrapper for opening said wrapper after use.

16. The method of claim 1 including the step of forming said wrapper from a conductive heat shrinkable material.

17. The method of covering a shoe on the foot of a wearer with a protective wrapper, comprising the steps of holding an oversized protective shoe shaped wrapper formed of heat shrinkable material in an opened configuration for insertion of said shoe and foot therein, inserting said shoe and foot in the open wrapper, and heat shrinking said wrapper about said shoe to conform the wrapper to the shoe.

18. The method as in claim 17 wherein said step of 12 heat shrinking comprises the step of supplying a flow of warm air over said wrapper and said shoe to heat shrink said wrapper.

19. The method of claim 17 including the step of forming said wrapper with an electrically conductive strip to provide a ground contact between the body of the wearer and the floor.

20. The method of claim 19 including the step of forming a tear strip in said wrapper for opening said wr r after use.

protective shoe covering comprising an oversized generally shoe-shaped wrapper having an access opening therein for insertion of a shoe while said shoe is on the foot of a wearer, said wrapper being formed of a heat-shrinkable material to be tightly drawn onto the shoe by an application of heat to the wrapper after the wrapper is placed on the shoe, thereby to define a sole and top portion surrounding this sole, heel and upper of said shoe.

22. A protective shoe covering as in claim 21 wherein said wrapper is a fully formed oversized overshoe and said access opening is in the top thereof..

23. A protective shoe covering as in claim 21 wherein said wrapper is formed with a toe portion, a sole portion, and spaced side portions rearwardly of said toe portion, said side portions defining said access opening in the heel and upper portion of said wrapper.

24. A protective shoe covering as in claim 21 wherein said material is electrically conductive.

25. A protective shoe covering as in claim 21 including an electrically conductive strip of material secured at one end to the sole of said wrapper, the other end of said strip being positioned adjacent said access opening and adapted to be placed in contact with the skin of the wearer for conducting electricity from the wearers body to the floor.

26. A protective shoe covering as in claim 25 wherein said strip is heat sealed to said wrapper.

27. A protective shoe covering as in claim 25 wherein said strip is heat sealed to said wrapper along a relatively narrow portion thereof, whereby said strip forms a tear strip for ripping said wrapper upon completion of use to facilitate removal thereof from said shoe.

28. A protective shoe covering as in claim 21 including a tear strip secured to said wrapper for tearing said wrapper upon completion of use to facilitate removal thereof from said shoes.

29. A protective shoe covering as in claim 21 wherein said material is alinged to shrink to a substantially greater extent in length than in width.

30. A protective shoe covering as in claim 21 wherein said material is air permeable.

Claims

1. The method of covering a shoe on the foot of a wearer with a protective wrapper, comprising the steps of positioning said wrapper for insertion of said shoe and foot therein, inserting said shoe and foot in the wrapper, and, after insertion of said shoe, heat shrinking said wrapper about said shoe, whereby said wrapper conforms to said shoe.

4. The method as in claim 1 wherein said step of heat shrinking comprises the step of supplying a flow of warm air over said wrapper and said shoe to shrink said wrapper.

5. The method as in claim 1 wherein said positioning step includes the step of holding said wrapper in a partially open configuration with at least two of its sides in spaced relation to permit insertion of said shoe in said wrapper.

6. The method as in claim 5 including the step of sealing said open wrapper sides after insertion of said shoe.

9. The method as in claim 5 including the steps of sensing the size of said shoe after insertion in said wrapper and sealing said wrapper sides adjacent said shoe to enclose said shoe prior to said heat shrinking step.

11. The method of claim 10 wherein said sensing step includes the step of moving said jaws to a position adjacent the heel of said shoe prior to said heat sealing step.

18. The method as in claim 17 wherein said step of heat shrinking comprises the step of supplying a flow of warm air over said wrapper and said shoe to heat shrink said wrapper.

20. The method of claim 19 including the step of forming a tear strip in said wrapper for opening said wrapper after use.

21. A protective shoe covering comprising an oversized generally shoe-shaped wrapper having an access opening therein for insertion of a shoe while said shoe is on the foot of a wearer, said wrapper being formed of a heat-shrinkable material to be tightly drawn onto the shoe by an application of heat to the wrapper after the wrapper is placed on the shoe, thereby to define a sole and top portion surrounding this sole, heel and upper of said shoe.

22. A protective shoe covering as in claim 21 wherein said wrapper is a fully formed oversized overshoe and said access opening is in the top thereof.

25. A protective shoe covering as in claim 21 including an electrically conductive strip of material secured at one end to the sole of said wrapper, the other end of said strip being positioned adjacent said access opening and adapted to be placed in contact with the skin of the wearer for conducting electricity from the wearer''s body to the floor.