US2750697A - Fabric protecting iron shoe - Google Patents

Description

June 19, 1956 s, JACOBSON 2,750,697

FABRIC PROTECTING IRON SHOE Filed Feb. 25, 1956 2 Sheets-Sheet l 5/0A/EV dncoaso/w I N V EN TOR.

m 1956 s. JACOBSON 2,750,697

FABRIC PROTECTING IRON SHOE Filed Feb. 23, 1956 2 Sheets-Sheet 2 5/.0A/Ey Jflcaasam INVENTOR.

firroewEK FABRIC PROTECTING IRON SHOE Sidney Jacobson, Van Nuys, Calif.

Application February 23, 1956, Serial No. 567,181

4 Claims. (CI. 38-97) This invention relates to an accessory for mounting on the under side of a portable iron or flat iron to be used in pressing heat-sensitive materials.

This application is a continuation-in-part of copending application Serial No. 471,180 entitled Fabric Protecting Shoe for Electric Iron, filed by Sidney Jacobson November 26, 1954, now abandoned.

In the use of either a simple electric iron or an electric steam iron a problem arises in the pressing of certain materials that are vulnerable to damage by excessive heat. These materials which include taffetas, gabardines, satins and practically all fabrics having synthetic fibers such as rayon, nylon, etc., are subject to damage by heat at temperatures well below temperatures that are safe for cotton and wool, and are especially subject to damage by direct contact with the metal surface of the heated iron. The damage consists in scaring the surface filaments to leave the fabric with a shiny appearance.

The invention meets this problem of safeguarding a delicate fabric by interposing a suitable heat-transfer medium between the iron and the fabric to prevent direct contact of the iron with the fabric and to provide sufficient resistance to heat flow to establish a safe temperature differential between the metal surface of the iron and the fibers of the fabric. Thus with the iron heated to an appropriate temperature that would ordinarily result in damage to the delicate fabric, the heat-transfer medium interposed by the invention would cause the heat flow to be retarded to such extent that the fabric would not be damaged even if the electric iron were inadvertently permitted to rest stationary on the fabric over a long period of time.

While the invention has utility for simple electric irons, it has special utility for the steam type electric iron and is both applicable to domestic irons in which the steam is generated inside the iron and applicable to commercial electric irons in which the steam is supplied to the iron through a flexible tube from an outside source. In the prevailing practice for pressing the delicate fabrics one procedure is to use a pressing cloth on the outer or right side of the fabric and another practice is to use the iron at a relatively low temperature directly on the inner or wrong side of the fabric. In the latter procedure great care must be exercised and it is usually difiicult to eliminate all of the wrinkles and creases from the fabric. The insertion between the iron and the delicate fabric of the heat transfer medium of the present invention makes it possible to press the right side of the fabric Without danger of damage.

Another troublesome problem that arises in the pressing of vulnerable fabrics is to avoid the formation of water spots or streaks caused by the emission of water or wet steam from the steam ports of the electric iron. This damage may be avoided by adjusting the iron to operate at a sufficiently high temperature to insure the production of dry steam. Such a temperature is too nited States l atent C 2,750,697 Patented June 19, 1956 high, however, for use in pressing heat-sensitive fabrics. The preferred practice of the invention solves this problem in two ways. In the first place the insertion of the heat-transfer medium between the iron and the fabric permits the iron to be used at substantially higher temperatures than usual for such fabrics. In the second place the preferred practice of the invention employs a perforated heat transfer medium and there is reason to believe that the perforations tend to prevent the formation of water spots and streaks on the fabric even when relatively wet steam is emitted from the iron.

in addition to meeting these problems, it is an object of the invention to provide an accessory for use on an electric iron that will decrease the frictional resistance to movement of the iron over fabric. Minimizing the friction to the sliding action of the iron not only reduces the fatigue of the operator but also reduces the tendency of the fabric to wrinkle at the leading edge of the iron. In this way, the invention produces better results than usual and does so in less time than usual. A further beneficial result of minimizing friction is longer service life for the heat-transfer medium.

A still further object of the invention is to provide a heat-transfer medium for the described purpose that minimizes the possibilities for damaging the fabrics by the impressing of foreign material thereon. The metal surface of the usual electric iron commonly picks up foreign material and in many instances becomes corroded or rusted with consequent depositing of material to discolor and otherwise damage the fabric.

In general the various objects of the invention are attained by the provision of an accessory or attachment in the form of a protecting shoe for an electric iron, which shoe has a bottom surface of a fluorinated polymer, more particularly, a surface of polymerized tetrafluoroethylene resin. The shoe may comprise a sheet of this material, which is commercially available under the trade name Teflon and the thickness of the sheet may be on the order of magnitude of of an inch. In the preferred practice of the invention at least the portion of the sheet in the region of the front half of the iron is perforated. In one practice of the invention with excellent results, the perforations are approximately 0.02 inch diameter with approximately 350 perforations per square inch. In another practice the perforations are approximately 0.625 inch in diameter or approximately inch in diameter, and are uniformly distributed in staggered rows with the perforations spaced apart approximately 4 inch center to center in each row. In this practice of the invention the sheet of polytetrafiuoroethylene is approximately 30% open with 98 openings per square inch. The sheet of the polytetrafluoroethylene is preferably 0.050 to 0.060 inch thick.

Tetrafluoroethylene resin has a number of properties which uniquely combine to meet the purpose of the invention. The material is durable in the presence of heat and can withstand temperatures as high as 570 degrees F. or higher for long periods of time without deterioration. The tetrafiuoroethylene may be polymerized according to; a method identical to or similar to one of those described in U. S. Patent 2,230,654. The material has a degree of stiffness that is desirable for the purpose of 'a thin shoe under an iron and in addition has a desirable degree of hardness as well as high tensile and flexural strength. These properties are not only important in the physical or mechanical functioning of the shoe but are also important in favoring a long service life for the shoe.

Tetrafluoroethylene resin has low thermal conductivity so that heat flows therethrough at a desirably retarded rate to maintain a substantial temperature differential between the heated metal surface of the iron and the fabric.

It has been found that this plastic material inherently maintains a heat differential adequate to prevent scorching and searing of heat-sensitive fabrics in the course of ordinary pressing operations.

A further property of tetrafluoroethylene resin that is of special utility in the practice of the invention is that the resin is chemically inert and will not react with any substances that are commonly present in fabrics and in pressing operations. The resin tends to present a clean surface at all times since it actually repels water as well as most other liquids and nothing sticks to it with any appreciable strength. Thus the tetrafluoroethylene resin is, in effect, self-cleaning and tends to maintain a smooth operating surface. In this regard a feature of the preferred practice of the invention is that the perforations serve as pockets to receive any foreign material that may be interposed between the shoe and the fabric. Since foreign matter will not adhere to the surface of the resin, the foreign matter is readily displaced into the perforations. The perforations do not ordinarily become clogged to any undesirable extent.

A special advantage of the tetrafluoroethylene resin is that a shoe made of this material moves across the surface of a fabric with an unexpectedly low coefficient of sliding friction. The shoe with the weight of the electric iron imposed thereon slides with such ease that it seems to have a self-lubricating surface. That is, sliding fric tion is reduced with use and wear. This is especially true of virgin Teflon, as distinguished from reclaimed Teflon. This property of the resin minimizes wear on fabrics by pressing operations and, of course, also minimizes wear on the part of the shoe itself to favor a long service life of the shoe.

When the perforated plastic shoe is used with a steam electric iron it provides a minute space between the bottom surface of the iron and the upper surface of the resin sheet through which steam may spread laterally and the numerous perforations distribute the steam uniformly to the surface of the fabric. A further important fact is that the perforations also provide numerous uniformly distributed zones in which heat radiates directly from the metal of the iron to the surface of the fabric without any possibility of the iron making actual contact with the fibers of the fabric.

The various features, objects and advantages of the invention may be understood from the following detailed description considered with the accompanying drawings.

Fig. l is a perspective view of the presently preferred embodiment of the invention as a shoe for use on an electric flat iron;

Fig. 2 is a side elevation of an electric flat iron with the accessory removably mounted thereon;

Fig. 3 is a fragmentary bottom view of an electric steam iron equipped with the removable shoe. the shoe being broken away to show the steam ports on the bottom of the iron;

Fig. 4 is a perspective view of a modification of the iron shoe of the invention;

Fig. 5 is a rolled sheet of perforated Teflon as it generally may be purchased in commerce;

Fig. 6 is a perspective view of Teflon which is molded to form around an iron; and

Fig. 7 is a bottom exploded perspective view showing how the Teflon shoe of the iron may be mounted to a shoe frame.

It will be apparent to those skilled in the art that the concept of providing an electric flat iron with a shoe having a surface of a resinous fluorinated polymer may be carried out in various ways in various practices of the invention.

In the embodiment of the invention selected for the present disclosure the accessory is in the form of a shoe, generally designated 10, of substantially the same configuration in plan as the electric flat iron with which it is intended to be used. The shoe it is made of polymerized tetrafluoroethylene resin sold commercially under the trademark Teflon and provides a bottom web or sole plate 11 dimensioned to cover the entire bottom surface of an electric flat iron. Preferably the shoe it) has upstanding flanges 12 on its two sides which meet at the front to form a nose 14. The nose 14 extends higher than the main portions of the two flanges 12 and is curved rearward, as shown, for positive engagement with the nose of an electric iron. The shoe it? also has an upstanding flange 15 on its back or trailing edge and, if desired, this flange may be continuous with the two flanges 12 as shown in the drawing. Such a shoe may be molded or may be fabricated by providing a sheet of the tetrafluoroethylene resin and forming the sheet to provide the described upstanding flanges. The thickness of the web or sole plate ill may, for example, be on the order of magnitude of of an inch.

The shoe it may be adapted for mounting on an electric iron in any suitable manner. In this particular practice of the invention, for example, a suitable coiled spring 20 is provided for this purpose. One end of the coiled spring 2t) may be permanently attached to one of the two upstanding flanges 12 by means of a piece of folded sheet metal 22. The piece of sheet metal 22 is attached to the flange 12 by small rivets 24, the folded sheet metal forming an eye for engagement by the end of the coiled spring as shown. The second end of the coiled spring is formed into a loop 25 which engages a hook 25, the hook being riveted to the second flange 12.

Fig. 2 shows the shoe 10 mounted on an electric iron 28, the shoe being held in place by the coiled spring 20 It will be noted that the flanges 12 together with the nose 1d of the shoe 10 cover the sides and front end of the electric iron to sufiicient height to keep the sides of the iron from making contact with fabric that is being pressed, even when the fabric wrinkles or forms a bulge in the path of movement of the iron. The flange 15 at the back edge affords the same protection for the fabric when the iron is moved backward.

The web or sole plate 11 of the shoe It may comprise a single layer of the polymerized tetrafluoroethylene resin of approximately A inch thick and preferably this web has numerous uniformly distributed perforations 30 as indicated in Fig. 3. As heretofore indicated the perforations 30 may be approximately 0.02 inch in diameter and uniformly distributed with approximately 350 perforations per square inch or the perforations may be approximately A inch in diameter distributed with approximately 98 perforations per square inch, and be spaced apart uniformly in staggered rows with center to center spacing of approximately inch in each row. The perforations may be distributed over the whole area of the web 15 or may be confined to a portion such as the front half portion of the web.

If the shoe 10 is used with a conventional electric iron that is not of the steam type and the iron is adjusted for moderate or low heat the shoe will serve as an effective means for retarding heat flow from the iron to such extent as to protect a delicate fabric from damage. The perforated shoe keeps the heated metal bottom surface of the iron from making direct searing contact with the fabric but, nevertheless, permits heat to flow from the iron to the fabric by conduction at a retarded rate and, in addition, permits heat to flow to the fabric by direct radia tion through the spaces provided by the perforations. Thus the combination of heat flow by conduction and heat flow by radiation is adequate for pressing a heat-sensitive fabric to a desirable finish when the iron is heated to an appropriate temperature but nevertheless does not damage the fabric.

When the shoe 10 is used with an electric iron of the steam type, it not only serves this same purpose of controlling the flow of heat to the delicate fabric but also serves as means to distribute the steam over the surface s'Jf the fabric. Fig. 3 shows the steam ports 32 on the under surface of the electric iron, these steam ports being positioned forwardly on the bottom surface of the iron. It is apparent that steam issuing from the ports 32 will be diverted laterally in all directions by the web 11 of the shoe since the steam ports 32 do not all register with the perforations 30 in the shoe web 11. Thus there is a tendency for a very thin steam blanket to form between the bottom of the iron and the web 11. This blanket of steam has access to the fabric through the numerous perforations 30 and is widely distributed by the perforations to supply the moisture needed for the desired pressing finish. Thus the perforations 30 not only provide spaces for heat radiation directly from the bottom surface of the iron to the fabric but also serve as essential portions of a steam distribution system.

It is apparent that the shoe may be quickly mounted on the iron 28 by means of the coiled spring and may likewise be quickly removed. A feature of the invention in this regard is that when the electric iron 28 has been used for a period of time at relatively high temperature for ironing cottons and it is desirable to switch to pressing a delicate fabric, it is not always necessary to let the iron cool down over an additional period of time. The temperature adjustment of the iron is, of course, immediately lowered but the mounting of the shoe on the iron permits the iron to be used immediately without waiting for the temperature of the iron to drop to the newly adjusted temperautre.

In the perspective view of Fig. 4 the iron shoe of the invention is indicated generally as 50. The iron shoe 50 comprises a frame or channel member 52 which is compressed around the upper edges of a perforated Teflon sheet 54. Eyes 58 are then provided on top of the frame 52 to which a spring 56 is secured. A portion of the frame 52 is cut away at 62 to provide means to introduce steam through the perforations of the Teflon sheet 54.

The manner in which the shoe 50 is manufactured is illustrated in Figs. 5, 6 and 7. In Fig. 5 the Teflon may come perforated from the manufacturer in sheet form as indicated at 60 in Fig. 5. Cutting the Teflon presents no particular problem. It thus may be cut according to any preselected pattern. After the sheet is cut, it is heated and molded in appropriate dies to the shape shown in Fig. 6. This makes the step of attaching it to the frame much easier.

Some Teflon sheet material tends to curl or ripple after it has been in use as an iron shoe for a relatively short period of time. However, it has been found that heat treating Teflon prevents this deformation. Preferably before the molded sheet, as indicated at 54 in both Figs. 6 and 7, is clamped Within the channel of the frame member 52, the molded sheet 54 is heated to between 400 and 450 degrees Fahrenheit for /5 to hour.

After the molded sheet 54 has been heat treated, the upper edges of the sheet are placed in the channel of the frame member 52 and the sides of the channel are pressed together in dies so that the sheet will be securely retained within the channel substantially all the way around the frame member 52.

My description in specific detail of a selected embodiment of the invention, by way of example and to illustrate the principles involved, will suggest various changes, substitutions and other departures from my disclosure that properly lie within the spirit and scope of the appended claims. For example, I have described the invention as embodied in a shoe for removable attachment to an iron of either the electric or electric steam type, but the invention may also be embodied in a combination of iron and shoe in which the shoe is permanently mounted on the ll'On.

What is claimed is:

1. A steam iron accessory for use in pressing heat sensitive fabrics, including fabrics made of synthetic materials, said accessory comprising: a perforated sheet of polymerized tetrafluoroethylene to cover the bottom surface of the iron, means connected to said sheet for engagement with the iron to prevent relative transverse movement of said sheet across the bottom surface of the iron, and means to attach said sheet to the iron.

2. A steam iron accessory for use in pressing heatsensitive fabrics, including fabrics made of synthetic materials, said accessory comprising: a perforated sheet of polytetrafluoroethylene to cover the bottom surface of the iron, said sheet having an upturned flange to fit around the sides of the iron to prevent relative transverse movement of said sheet across the bottom surface of the iron, and means to attach said sheet to the iron.

3. A steam iron accessory for use in pressing heatsensitive fabrics, including fabrics made of synthetic materials, said accessory comprising: a perforated sheet of polytetrafluoroethylene to cover the bottom surface of the iron, said sheet having an upturned flange to fit around the sides of the iron to prevent relative transverse movement of said sheet across the bottom surface of the iron, an inverted U-shaped member provided with a channel to receive the upwardly extending flange, said flange being compressed and thereby retained between the sides of said U-shaped member, and means connected from said 'U-shaped member to fix said sheet in a position contiguous to the bottom surface of the iron with said flange and U-shaped member contiguous to the sides of the iron.

4. A steam iron accessory comprising: a perforated sheet of heat treated polymerized tetrafluoroethylene to cover the bottom surface of the iron, and means connected to said sheet above the bottom surface thereof to attach said sheet to said iron in a substantially fixed position contiguous to the bottom surface of the iron.

References Cited in the file of this patent UNITED STATES PATENTS 2,142,032 Matsen Dec. 27, 1938 2,299,202 Bass Oct. 20, 1942 2,400,099 Brubaker et al May 14, 1946 2,556,008 Spalding June 5, 1951 2,659,167 Weldon Nov. 17, 1953 2,738,603 Towne Mar. 20, 1956

Claims (1)

1. 4. A STEAM IRON ACCESSORY COMPRISING: A PERFORATED SHEET OF HEAT TREATED POLYMERIZED TETRAFLUOROETHYLENE TO COVER THE BOTTOM SURFACE OF THE IRON, AND MEANS CONNECTED TO SAID SHEET ABOVE THE BOTTOM SURFACE THEREOF TO ATTACH SAID SHEET TO SAID IRON IN A SUBSTANTIALLY FIXED POSITION CONTIGUOUS TO THE BOTTOM SURFACE OF THE IRON.

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