US2837847A - Steam iron - Google Patents

Description

June 10, 1958 E. G. FRANKLIN ET AL 2,837,847

' STEAM IRON Filed Nov. 18, 1953 5 Sheets-Sheet 1 6y 25% Arrows/5 n 195.8 I E. G. FRANKLIN ET AL 2,337,347

' STEAM IRON Filed Nov. 18, 1953 v 5 Sheets-Sheet 2 Avvawroes Emmwm 6. FRANKLIN rammw l/mpmsms flan NK B. J5 WEFZ' 5r C, ATTORNEY June 10, 1958 v E. G. FRANKLIN ET AL 2,837,847

STEAM IRON Filed Nov. 18, 1953 5 Sheets-Sheet s //v|//vro/?s [mm/w afmmmzm -$m-r0- 1 /01 MBER6 FRANK 18. JE WENT W AfTOE/VEY United States, PatentDv 17 Claims. (Cl. sir-77 The present invention relates to steam irons and more particularly to irons which are capable of selective operation either. as steam irons or dry irons, as well as to improved features contributing to greater ease and efiiciency in steam ironing operation.

The steam irons known or generally available on the market prior to the present invention have been of three different primary types. In one of these types, the'total supply of water is confined in a relatively large boiler which extends over a major area of the iron.

Either the soleplate of the iron or some separate heating unit is provided to heat substantially all of the water to the boiling point for the generation of steam. The steam is then conducted to the vicinity of the bottom of the iron where it can be projected on the material being ironed. In irons of this type, which have been referred to as the tea-kettle type of steam iron, substantially the entire available supply of water in'the iron must be broughtto the boiling temperature before steam is avail able. Not only does this .present certain operating disadvantages in view of the longer time required to heat such a large volume of water, but furthermore, irons of this type offer a definite safety problem. When a relatively large body of Water is boiled, it is possible to gem crate steam under certain circumstances at such a high rate as to build up dangerous pressures within the iron. Particularly is this true in irons of this type, where a valve is provided to control the flow of steam to the material being ironed. If the valve is inadvertently left closed, or if the steam passages are too small in cross section, serious pressures may build up with consequent danger to the operator.

The second general type of iron which has been available prior to the present invention may be referred to as the flash type of steam iron. In such irons water is fed a drop or two at a time from a supply reservoir to a flash generating chamber which is maintained at a relatively high temperature. Theoretically, each drop is flashed into steam the moment it strikes the hot surfaces of this generating chamber and the steam is then conducted to the material being ironed. While irons of the flash type have the advantage that the main body of water in the supply reservoir need not be heated, they have numerous other disadvantages, some of which have not been generally recognized.

For example, if the control valve between the tank and generating chamber is opened before the generating chamber is at a proper heat, the water will not be flashed into steam and may accumulate in such quantities that it will pass through the discharge ports and cause spots on the material to be ironed. Similar dripping of water from the iron may occur, if the operator is' not suflic'iently skilled to adjust the rate of liquid feed accurately during operation. Thus, water may be fed to the generatingchamber faster than it can be flashed into steam with the result that portions of the liquid ultimately overflow through the steam outlet tubes. The use of metering valves with small orifices in irons of this type may also lead to unsatisfactory operation due to accumulationof deposits from the water which may further restrict the valve openings after short periods of service.

One of the generally supposed advantages of the flash type ste'am iron has been the fact that the generating chamber could be maintained so hot that the water would c 2,837,847 C Patented June 10,

not only be vaporized into steam, but the steam itself could be superheated and dried before it was passed to the material beneath the soleplate. We have found, however, that for many fabrics a pressing operation is more eflicient if the steam discharged onto the fabric is relatively inoist, i. e., if its temperature is more nearly at the boiling point of the liquid. i It is ditfic'ult to maintain such temperatiires in a flash type of iron since the generating chambers are too small and too hot to prevent superheating of the steam.

There have also been some limited prior disclosures of a third type of iron in which a steam generating boiler contains a relatively small volume of water which i's" replenished from a-stipply source during'operation. As far as We are aware, such irons have eitherrequired special metering or supply valve arrangements to feed the Water to the boiler, or they have required hermetically sealed reservoirs which may present a substantial safety problem if heat is conducted even indirectly to the reservoir during operation. In a sealed reservoir air expansiorl will also force water out more rapidly than the boiler can convert it to steam, with consequent danger of water spots on the material to be ironed.

It is accordingly one object of. the present invention to provide an improved steam iron construction of this third type which shall not be subject to the major disadvantages of any of the types discussed above.

A further object is an improved steam iron in which a boiler of limited volume and a supply reservoir are connected so as to eliminate the need of special metering valves or orifices.

Another object is a steam iron construction in which adequate control of the steaming rate is achieved by proper choice of soleplate materials, heat in ut, and

boiler dimensions without the need of precise fluid metering devices.

An additional object is an improved construction in which steam is generated in a body of liquid which is in direct contact with "a predetermined limited area of the flatiron soleplate.

A further object is an improved steam iron construction in which the boiler shall include a limitedvolume of water 'at all times in order that steam may be generated in the presence of water and its temperature maifi tained close to the boiling temperature of the water.

Another object is the provision of an improved con struction in which the steaming operation may be arrested automatically in response to movement of the iron to arest position.

An additional object is a steam iron construction designed to permit selectiveinovernent of the iron to either one of two alternate rest positions, with automatic interruption of the steaming operation in each of said posh tions.

Still another object of the invention is a steam iron construction in which the main water supply is contained in a reservoir vented to atmosphere at all times and inwhich improved construction and location of the venting means permits movement of the iron to a rest position Without loss of fluid. H

, Other objects of the invention will be apparent from the following description in which certain preferred embodir'nents of the invention are described.

In the drawings which accompany this application, Figure 1 is a side view of an improved steam iron according to the present invention, with certain portions broken away and certain portions shown in section for convenience. I i

Fig. 2 is a partial similar side view of a modified form of construction according to the invention.

Fig. 3 is a partial sectional view taken on the line 3 3 of Fig. 2.

Fig. 4 is a view similar bodiment of the present invention.

F Fig. 5 is a partial sectional view on the line 5--5 of Fig. 6 is an'enlarged partial perspective view of part of the device of Fig. 4.

Fig. 7 is a front view of the device of Fig. 4 with portions broken away and portions shown in section for clearness.

, Fig. 8 is a view similar to Fig. 7, but with the iron tilted to one of its side rest positions.

Fig. 9 is a partial view similar to Fig. 8 showing details of the reservoir venting means.

Fig. 10 is a perspective view of the iron in its rest position corresponding to Fig. 8, but with portions broken away to show the liquid level and other details within the tank.

The iron shown in Fig. 1 is indicated generally at and includes a soleplate 22 having an upper surface 24 and a lower or bottom surface 26. Surface 26 is designed for engagement with the material to be pressed.

Heating means for the soleplate 22 are provided, such heating means being shown in the present instance as a cast-in element 28 of the sheathed or Calrod type. The element 28 extends across the front of the soleplate and includes portions extending rearwardly along each side of the soleplate terminating in suitable terminals 30.

One of the heating element terminals 30 is suitably connected to one of the supply leads 32, while the other supply lead 34 is connected through a thermal switch 36 and a further lead 38 to the remaining heating element terminal (not shown). The thermal switch 36 provides adjustable control means for the heating element for maintaining the desired fiatiron soleplate temperatures. The switch includes a bottom plate or flange 40' suitably secured to the soleplate by screws 42 or other means, so that the thermally responsive portion (not shown) of the switch is in direct heat-conductive relationship with the soleplate. The switch 36 includes adjusting means operatively connected to a manual adjusting knob 44 which is accessible to the operator of the iron.

7 According to one feature of the present invention, a steam generating boiler 46 is provided above the soleplate. Boiler 46 includes a first or lower portion which is in direct heat conductive relationship with a relatively small predetermined area of the upper surface 24 of soleplate 22. This predetermined area is designated at 48 in Fig. 1 and in this particular embodiment of the invention, the upper surface of the soleplate in this area serves directly as the bottom of the steam generating boiler'chamber 46.

Cooperating with this predetermined area 48 of the soleplate upper surface is an open bottomed upper boiler portion or chamber member 50 which has its lower edges 52 secured in sealing engagement around the edges of the soleplate surface area 48 by suitable screws 54 or equivalent fastening means. A sealing member may be included between the boiler chamber 50 and the soleplate to insure a water tight joint around the bottom of the boiler.

In this particular case, the chamber member 50 is substantially cylindrical and its lower edges at 56 and 58 therefore constitute portions of a circle by which the area 48 is bounded and defined.

According to an important aspect of the present invention, the steam generating boiler 46'is adapted to contain only a limited predetermined amount of liquid into Fig. 1 of a preferred emdicated at 60 during the steam generating and ironing operation. Portions of this liquid completely cover the entire bottom portion of the boiler including all parts of the soleplate area within the boiler. The cross-sectional area of the boiler 46 is relatively limited and the predetermined area 48 of the soleplate upper surface which is used for supplying heat to generate steam from the liquid in the boiler represents only a small fraction of plate to the reservoir.

the total soleplate surface area. Thus the relative volume of water which must be brought to the boiling point initially, before steam generation can take place, is extremely small in comparison with the volumes of water involved in the ordinary teakettle type of iron. At the same time, the heat energy required for steam generation is obtained from a relatively small fraction of the total soleplate area. Thus adequate heat is still available in the remaining portions of the soleplate to maintain the soleplate bottom surface at the appropriate temperatures for satisfactory ironing.

As pointed out above, the boiler chamber dimensions are limited. In fact it is desirable that the maximum boiler chamber cross-section parallel to the soleplate shall be no greater than the predetermined soleplate area used for steam generation. In the preferred embodiment to be described below, the effective boiler chamber crosssection is even smaller than said soleplate area. Thus a compact, efiicient and economical construction is provided in which the boiler chamber requires a minimum of the available area above the soleplate.

The soleplate upper surface area used as the bottom of the boiler need not be substantially larger than one square inch. Actually such area may fall in the range from substantially 0.7 to 0.9 sq. in. and preferably around 0.8 sq. in. for the operating temperature contemplated in this invention. Thus the steam generating area will be less than to 4 of the total soleplate bottom surface area.

Toimprove the operating characteristics of the device and to insure adequate and rapid transfer of heat energy from the heating element 28'to both the boiling area 48 of the soleplate upper surface and the lower pressing surface 26 of thesoleplate, We prefer to construct the sole plate of material having a relatively high heat conductivity. This heat conductivity should be in the range from substantially 0.24 to 1.0 measured in c. g. s. units (calories per sq. centimeter area per centimeter thickness per degrees centigrade per second). Aluminum and its alloys constitute the preferred soleplate materials for use in combination with the other features of the present invention. The use of materials in this higher conductivity range also insures rapid and accurate control of soleplate temperatures by the thermal switch, since the thermally responsive portion of the switch can respond more promptly to heat losses in the steam generating area and at the bottom of the soleplate as well as to heat input from the heating element.

The present invention also contemplates the provision of means for maintaining the desired limited volume of liquid 60 in the boiling chamber 46, and replenishing this liquid as it is converted into steam. For this purpose, the iron 20 includes a reservoir 62 having a bottom wall 64, side walls 66, and a top wall 68 secured together in liquid-tight relation in known manner. The reservoir is mounted on the iron with the bottom 64 of the reservoir spaced above the soleplate 22 and in relatively poor heat conducting relation therewith. For this purpose, the reservoir is shown as spaced from the soleplate by supporting studs 70 and 72. Other means of supporting the reservoir may be used in appropriate cases, provided such means are chosen so as to be consistant with the over-all objective of minimizing to the greatest possible extent the transmission of heat from the sole- Thus the reservoir is insulated as effectively as possible from the heat of the soleplate.

In the form of reservoir shown in Fig. 1 it will be noted that the tank 62 includes portions substantially surrounding the boiler chamber 50. The wall 74 of the reservoir which surrounds the boiler is spaced substantially therefrom in order to provide an insulating air space 76 and prevent transfer of heat from the boiler to the tank.

For the transfer of liquid from the reservoir 62 to the assume boiler 46 a suitablewater conduit 78 is provided. This eon'duit has one end 80 which opens into the bottom at the steam generating boiler 46 and a second end 82 opening into the bottom of the reservoir 62. Thus the water conduit 78 joins the water containing portions of the reservoir and boiler. The cross-section of this conduit 78 is relatively large and is Completely free of restricted valve openings or other metering devices. In fact the cross-section of this conduit should be sufficiently great to provide for transfer of liquid from the tank 62 to boiler 46 much more rapidly than the liquid could possibly be evaporated frornthe boiler. The use of such a relatively large cross-section in conduit 78 is also instrumental in preventing the liming and clogging which often occur after relatively short periods of operation in steam irons having small metering orifices or valves, especially when such irons are used with relatively hard waters. The iron of this embodiment may be equipped with a simple non-metering onoff valve in this water conduit, as in the embodiment of Figs. 4-10 described below. Such a valve is movable between only two positions for steam or dry ironing operation and is not adjustable to regulate the steaming rate.

The liquid reservoir 62 includes means by which the reservoir can be filled to a predetermined level. In this case, the filling means is shown as constituting a filling opening 84 in the top of the tank. This opening may be closed by a threaded filling plug 86, during operation. The plug is removed when it is desired to fill the tank through the opening. In this case, the location of the plug and opening permits filling the reservoir'62 substantially to capacity.

Another element of the present invention is the provision of means venting the liquid-reservoir 62 to atmosphere at all times during operation of the iron. This venting means is shown in the present instance in the form of an air hole or passage 88 in the filling plug 86. The venting means serves the double purpose of preventing any substantial increase of pressure within the reservoir 62 and also of insuring the free flow of liquid from the reservoir 62 into the steamy generating boiler 46.

Since the reservoir is vented to atmosphere by the opening 88, and since the steam boiler is also opened to atmosphere by way of the steam tube to be described below, the construction is such that the liquid level within the steam generating boiler 46 will automatically be maintained at substantially the same level as the liquid in the reservoir. The reservoir and boiler liquid levels are shown in Fig. l at 90 and 92 respectively.

While these levels will gradually drop as the liquid is converted into steam during normal operation, the change in level Within the boiler 46 will have no substantial effect on the rate of steam generation, since this rate is dependent primarily on the size and temperature of the predetermined soleplate area 48 at the bottom of the boiler. The relatively large water conduit 78 provides rapid equalization of liquid levels in the reservoir and boiler to insure the presence of a limited amount of liquid in the boiler at all times. Thus steam is generated in the presence of boiling liquid, so that moist rather than superheated steam may be obtained.

As shown in Fig. 1, the upper portion of the steam generating boiler extend substantially above the maximumv liquid level of the reservoir 62. Thus there will be a substantial upper portion of the generating chamber 46 adjacent its top 94 which may receive the steam generated from the liquid within the boiler. In order to convey this steam to the material to be ironed, a steam conduit 96 is provided. This conduit has one end 98 opening into the upper portion of the steam generating boiler 46' near the top wall 94 and above the maximum liquid level in reservoir 62. The other end 100 of the steam conduit 96 is open to atmosphere at a point adapted to discharge steam out on the material being ironed.

In case, the end is actually led down through a suitable opening in the reservoir 62 and through the soleplate 22, so that the steam strikes the material at a point beneath the soleplate bottom surface 26. The lower portion of the steam conduit 96 may be threaded as indicated at 102 and a suitable lock nut 104 may be provided to assist in locating the lower end of this con duit. The conduit is rigidly connected to the boiler chaniber member 50 adjacent the end 98 and is thus also held in place by the securing means for the boiler at 54.

To facilitate manipulation of the iron by a user, a suitable handle 106 is provided. In this case the handle includes a substantially horizontal hand grasping or carrying portion and a rearhandle post secured to the rear of the liquid reservoir 62 in known manner. The rear handle post may be hollowed as shown at 108 in order to accommodate the current supply leads 32 and 34 from the supply cord 110.

lnoperation, with the reservoir filled with water, the steaming rate of this iron may be adjusted selectively for pressing dilferent fabrics. This selective adjustment is achieved by varying the temperature adjustment of the thermal switch. Thus the soleplate temperature is selectively altered. Since the same predetermined soleplate area is effective for all adjustments, the changes in soleplate temperature can be used to vary the rate of steam generation's at said area'for selective'steam pressing of different fabrics.

The modification shown in Figs. 2 and 3 is similar in manyrespects to the steam iron of Fig. 1. This embodi ment'includes a soleplate 112 similar to the soleplate 22 and having top and bottom surfaces 114 and 116. An identical heating element 28 may be used to heat. this soleplate and is cast into the plate in the configuration previously described.

A boiler chamber member 118 projects upwardly from the soleplate and cooperates with a relatively small predetermined area 120 of the-soleplate to provide the complete boiling unit. The chamber member 118 in this case is threaded into-a small recess of the soleplate upper surface at 122, and a sealing gasket 124 may 'be provided to insure a water tight'j'oint.

The steam conduit means of this embodiment differs from that of the previous example in that the conduit extends downwardly within the boiler through the mass of boiling liquid and thence directly out through'the bottom of the soleplate. This steam conduit is shown at 126 and; has its upper end opening near the top of the boiler chamber 118 well above the'maxi'mnm liquid level in the boiler and reservoir. The lower end of the steam conduit is threaded at 128 into a threaded recess in the center of the boiler area of the soleplate upper surface. An opening 130 through the bottom surface 116 of the soleplate communicates with the lower end of the steam tube to provide an opening to atmosphere through which the steam. can bedisch'arged on the material being ironed.

To supply and maintain the desired limited volume of liquid in the boiler 118, a reservoir 132 similar to reservoir 62 of Fig. l is provided. The reservoir communicates with the boiler through a water conduit 134 of relatively large cross-section, which is more than adequate to replenishthe liquid in the boiler as rapidly as it can be boiled away. This water conduit 134; may be provided as an integral projection from the boiler chamber 118 or may beforrned' as a separate member. The integral projection shown in Fig. 2 is then further provided with suitable connections at the bottom of the liquid reservoir 132 by means of the sealing gasket 136 and locking screws 138. Thus the water conduit may'serve as a means of supporting the reservoir, with the insulation means 136 preferably having some heat insulating properties to reduce the transmission of heat from the soleplate to the liquid reservoir.

Because the water conduit 134 is of relatively-large cross-section and becaus'ethe tank132 is vented as in the vcase of thedevice of Fig. 1, while .the steam conduit126 is open to atmosphere at its lower end, the level of liquid 140 in. the boiler .will be maintained at substantially the same level as that in the tank 132. during operation.

A control thermostat 36 is supplied which may be identical with that of Fig. 1 to serve as control means for maintaining the desired temperatures in the soleplate. The operation of the device of Figs. 2 and 3 will be essentially similar to that of the device of Fig. 1, with certain improvements due to location of the steam conduit. The

arrangement of the steam conduit so that it passes back down through the boiling liquid 140 serves a double purpose. p

First of all, since the tube is within the boiling liquid, the temperature cannot substantially exceed that of the boiling liquid butmust remain substantially near the boil-' ing point-of water. Thus the steam passing through the steam conduit will remain essentially at the boiling point temperature and will have no opportunity to become superheated to an undesirable degree before it reaches the material. At the same time, not only does this arrangement prevent overheating of the steam, but it further insures maintenance of the steam at the boiling point temperature so that condensation and the formation of water droplets will be avoided. The location of the steam tube within the water chamber also reduces to some extent the total volume of water for a given boiler diameter.

Because of the presence of the steam tube, it will also be noted that the effective boiling area at the bottom of chamber 118 may be considered as of annular configuration as shown at 120 in Fig. 3. This figure also indicates a desirable adjustment of the resistance of the heating element 28. As illustrated, the portion of the element'at each side of the steam generating area 120 is designed to provide a higher rate of heat energy input than the remaining portions of the element. Thus, between the points 142 and 144 atone side of the generating area, and also between the points 146 and 148 at the other side of the area, the heating element has a greater resistance per unit length than in the front loop portion between points 142'and 146, or the rear portions behind points 144 and 148.

While the specific resistance and wattage characteristics may vary to some extent depending on the relative location of the element in the soleplate, the expected operating temperatures and heat losses of the particular iron, the sizeof the total soleplate area and steam generating area, and the desired steaming rate, the following dimensions have proved satisfactory in one practical embodiment of the invention. In this case, the total area of the bottom surface of the soleplate was substantially 31 square inches. The internal diameter of the steam generating boiler 118 was 1%; inches and the external diameter of the steam conduit 126 was /2 inch. Thus the total area of the annular generating portion 120 of the soleplate upper surface was 0.79 or substantially 0.8 square inch.

The total wattage of heating element 28 was 1100 watts, and the wattage per unit length was as follows. In the front loop portion 28 the wattage was watts per inch for a total original length of 2 inches before the element was bent into U-shape. From points 142 to 146 back to the points 144 and 148 the wattage was watts per inch over a total length in each case of 2% inches.

The wattage of the remaining rear portions of the element was substantially 82 watts per inch with the length of each rear portion being substantially 2% inches. In this particular example, the soleplate was made of an aluminum alloy having a thermal conductivity of substantially 0.33 c. g. s. units at 68 F.

While these specific values and materials can be modified to meet the needs of a particular form of construction, it is important in any case that the thermal conductivity of the material and the construction and relativo location of theheating.element, .steam,generating area and thermal switch. be so chosenas to supply adequate heat energy to the generating area at all times in spite of losses through the soleplate to the material being ironed. For this purpose, substantially at least half the total expected wattage of the heating element should be available at the small predetermined steam generating area of the soleplate upper surface. In terms of both wattage and temperature, the heat energy available at this area for actual conversion of Water to steam should bein the range from 250 to 600 watts while the soleplate temperature is maintained in the range from substantially 325-F. to 450- F. This combinnation will provide satisfactory ironing temperatures at the bottom of the soleplate as well as sufficient heat energy for generation of from 8 to 12 grams of steam per minute, during steam ironing operation. The exact rate of steam generation will again depend on the exact selective setting of the thermal switch, which determines the specific soleplate temperature within the above range.

The device shown in Figs. 4-10 inclusive illustrates a preferred embodiment of the present invention incorporating features of the devices of the previous embodiments in combination with further improvements. As shown in Fig. 4, the iron includes a soleplate 150 having top and bottom surfaces 152 and 154 respectively. The heating element 28, identical to that previously described, is cast into the soleplate as a means for heating the same. A thermal switch 156 provides means controlling the heating element 28-and is connected in a manner similar to that previously described. In this case, the thermally responsive actuating member for the switch 156 is illustrated as a bimetallic strip 158 secured at 160 in close heat-conducting relationship to the soleplate upper sur face just in back of the steam generating area. 1

The steam generating boiler in the present example is assembled in combination with the steam conduit and soleplate as follows. A relatively small annular area 162 is provided on the upper sunface of the soleplate to serve as the bottom of the boiler chamber in a manner similar to that illustrated in Figs. 2 and 3. In the center. of this annular area the soleplate includes a downwardly extending opening which is threaded at 164 to receive the lower end of the steam conduit 166. The opening into which the steam conduit is threaded then extends downwardly at 168 to the bottom of the soleplate, where it communicates with a series of steam grooves 170. These grooves serve to convey the steam over a wide area of the bottom surface of the soleplate.

In order to be sure that the steam conduit is open to atmosphere at all times and is not blocked by the material being ironed so as to cause back pressures within the boiler, the outer ends of at least some of the steam grooves are provided with vent openings 172. These openings extend through a beveled edge portion 174 of the soleplate at a point above the level of the bottom surface 154. Thus the vent openings 172 will still discharge steam to the material being ironed even it the material is positioned so as to block substantially the lower end of opening 168. We have found that the total cross-section of all of the openings 172 should substantially equal the cross-section of the steam passage 168 and conduit 166 in order to make sure that undesirable back pressures are avoided.

The steam generating boiler itself includes a cylindrical body portion 176 surrounding the steam conduit 166. The lower end of body 176 is flared outwardly and downwardly to provide a portion of increasing diameter at 178 for engagement around the edges of the annular generating area 162 on the top surface 152 of the soleplate. A gasket member 180 is provided between the flared lower end 178 of the cylindrical boiler member and the soleplate itself in order to provide a liquid tight joint and also in order to minimize the transmission of ease-sat cross arm 182 to clamp the boiler section 176 firmly.

against the sealing and heat insulating gasket 180.

According to a feature of this preferred embodiment of the invention. the boiler includes means restricting its e'lfective internal cross-sectional area from a point just above the soleplate to an amount substantially less than t the area of the annular steam generating portion 162 at the bottom of the boiler. In the present case this means includes two features of construction. The first feature, which has already been described, is the reduction in the diameter of the boiler portion 176 as compared to the portion 173 which engages the edges of the soleplate boiling area. Thus the internal diameterof the cylindrical portion 176 is somewhat less than the maximum external diameter of the annular generating section 162.

Thesecond feature which is used to reduce the crosssectional area within the portion of the boiler contain ing" liquid to be boiled is the introduction of some sort of'insert or filler means within the boiler. In this case, a'cylindrical sleeve 186 is mounted on the steam tube 166. This sleeve may be considered as an annular cylindrical section having an internal diameteradapted to fit the steam conduit 166 and having an external diameter whichis sufficient to fill a substantial portion of the remaining free cross-sectional area inside the boiler portion 176. Preferably the reduction in cross-section within the portion 176 which is available for the containing of liquid should be great enough so that this cross-section is substantially only 50% of the area of the annular portion 162.-

The volume reducing sleeve 186 may be held in position on the steamconduit 166 by the engagement of its upper end beneath the spider or cross-arm 182 and by the provision of a securing nut 188 beneath the sleeve. It will be understood that in the original assembly of this portion of the construction, the nut 188 and sleeve 186 would first be placed on thesteam tube 166, after which the tube would be threaded into the soleplate 150. The boiler section 176 could then betelescoped outwardly over the steam conduit 166 and the retaining nut 184 placed in position and tightened to lock the assembly.

The upper or second portion of the steam generating boiler is completed by a dome or cylindrical cap, which is closed at its upper end as indicated at 190. This dome 190 has its lower peripheral edge 192 received within a mating seat 194 at the upper end of the boiler portion 176. Any suitable connection may be used at this point, such as the use of threads on the mating parts, or simply the use of a suitable cement.

Beforethe boiler or steam dome 190 is completely secured in position, it is contemplated in this preferred form of the invention that a particular location and arrangement of batlles will be provided. These-battles are illustrated at 196 and 198 respectively and. further details of the baffie construction andarrangementare shown in Fig; 5. Each bafile is internally. threaded along an axis'wh'ich extends at an acute angleto the plane of the baflie. Thus when each bafiie is screwed onto the threadedsteam tube 166, it will assume an angularly oriented position as shown in Fig. 4. As illustrated in the drawings, set screws 200 may be used to lock the bafile's' in their adjusted positions and prevent further rotation thereof. The lower bame then extends upwardly at an angle from the front to the rear of the" steam containing portion of the" boiler, while the upper bafiie extends upwardly from rear to front of the steam dome.

It will be noted-that the rear" portion or thelewer b'aflie 196 and the forward portion of the u seeisaflie 198. fit relatively closely within-the steam dome 190. At the same time-portions of reduced diameter are provided at the front lower portion of'the lower bathe 1 96 and the rear lower portion of the upper bafile 198. These cutaway portions extend substantially half-way around each bafiie as shown and thus provide a semi-annular passage at the front of the lower baflle and at the rearof the upper baffle. The upper portions of the respective baffles fit the steam dome suificiently closely to provide downwardly facing pockets. These pockets effectively trap any drops or particles of moisture which might tend to be carried upwardly by the violence of the boiling action within the lower boiler portion 176.

In order to supply and maintain thedesired limited voltime of liquid in the boiler portion 176, a supply tank or reservoir 202 is mounted on the soleplatewith the bottom of the tank spaced above the soleplate and in poor heat conducting relation therewith. A- water conduit 204 extends between the lower or water containing portions of the reservoir and boiler in a manner similar to that described in the previous embodiments. however, the end 206 ofthe conduit which communicates with the reservoir 202 is located on the longitudinal axis of the soleplate and tank forwardly ofthe boiler area for a purpose to be described below. The cross-section of the water conduit is again large enough to equalize the water levels in the tank and boiler very rapidly as part of the water in the boiler "is'convertcd into steam.

In order to permit selective operation of the applianceas either a steam ironor a'dry iron, a simple onoif valve arrangement is provided. The valve member in this case is illustrated as having a portion 203 with a conical tip designed'to close the opening 206 in the con duit when dry ironing operation is desired. This valve'is' contained in a small housing'210 having an opening 212 at its forward end for passage of water from the reservoir a relatively close fitting 'eccentrically located opening 220' in the upper end of a vent tube 222. The lower end of this vent tube is secured at 224 to the reservoir. Thus the vent tube serves both as a supporting means for the valve stem 214 and also as a means for maintaining atmospheric pressure above the liquid in the reservoir 202 and thus equalizing the water levels in the reservoir and boiler.

The eccentric opening 220 through which the valve stem 214 projects at the top of the vent tube 222 is in this case located nearer the rear edge of the vent tube than the front, as illustrated in further detail in Fig. 6. The operating button 216 for the valve includes a downwardly extending projection 226. In the position of Fig. 4' this projection is adapted. to slip past the edge of the tube 222 andpermit the spring 218 to urge the valve to its closed position.

When thebutton 216 israised'and rotated, however, the projection 226 maybe engaged on the top surface 228 of the vent tube as shown in Fig. 6 to hold the valve.

stem and valve upwardly against the resilience of spring 218. In this position a relatively large opening will be provided to permit free flow of liquid from the reservoir 202 throughthe conduit 204 without any restrictions or metering orifices. The edges of the projection 226 on the button 216 may be sloped or beveled at 230 to facilitate, upward camrningofthezbutton by a simple rotary-move-.-

ment.

In this case,

-The-upper end of the venttube 222 is provided with an internal chamber 234 of predetermined volume for a purpose described below. A vent opening 232 in the forward end of this tube is spaced below the top of the chamber 234 as illustrated. The vent opening 232 and the space between the remaining portions of the vent tube and the valve stem 214 thus provide for venting the upper portion of the reservoir 202.

According to a further important feature of the preierred form of the invention illustrated in these figures, the steam iron is provided with means for supporting the iron in a rest position. In this particular case the iron is adapted to be supported selectively in either of two rest positions, in which the iron istilted toward one side or the other from its normal operating position. One such position isillustrated in Fig. 8 from which it will be apparent thatthe iron is adapted to be tipped selectively to either side on one of the side rest projections 236 or 238; These projections serve to space the tank and soleplate somewhat above the surface 240 on which the iron is to rest, in order to prevent damage to thesupporting surface by the heat of the soleplate.

Cooperating with either of the rests 236 or 238 in this case are suitable projections on the handle of the iron. This handle, as shown particularly in Fig. 4, includes a substantially horizontal hand grasping portion 242 integrally connected to front and rear handle posts 244 and 246 respectively. The rear handle post is provided with a hollow chamber at 248 for accommodation of the supply cord leads 250 in known manner.

The front handle post is hollowed out as shown at 252 in order that the handle may surround and protect a portion of steam boiler. There is, however, a space between the steam dome and boiler members on the one hand and the handle post on the other hand, in order to minimize the transmission of undesired heat to the handle portion.

, :The particular handle projections which cooperate with the side rest projections 236 and 238 to maintain the iron in either of its rest positions may either be provided as integral portions of the handle itself or such supporting portions may be provided by the addition of a separate member. In this case, such a member is shown at 254 and includes a laterally extending substantially horizontal portion 256 secured by suitable fastening means 258 to the top of the handle at the front handle post portion. At either end of the portion 256, the strip, which is preferably metallic, is bent downwardly to provide supporting legs 260 and 262 secured by screws 264 and 266 to opposite sides of the front handle post. Thus the member 254 provides corner portions 268 and 270 which serve to space the handle and the upper end of the steam dome slightly above the surface 240 on which the iron is rested. It will be understood that the projecting corner 268 cooperates with the side rest projection 236 to provide one side rest position, while the projection 270 cooperates with the side rest projection 238 to provide the other side rest position (not shown).

As illustrated in Fig. 10, the side rest members 236 and 238 have relatively long bearing portions 27 2 which are inclined at an angle to the longitudinal axis of the iron. Thus the nose or forward portion of the longitudinal axis of the iron is spaced substantially higher above the supporting surface 240 than the rear portion of the iron axis.

The particular orientation of the edges 272 of the side rests 236 and 238 cooperates with the specific location of the opening 212 in the valve housing 210 through which water passes from reservoir 202 to the water conduit 204 and with the particular fill-limiting means to be described below, to provide a construction in which the flow of liquid from the reservoir to the boiler will be stopped automatically without the manipulation of any value, whenever the iron is tilted into either of its selective side rest positions. Thus, as shown particularly in Fig. 10, by suitable limitation of the total quantity of water in the 12 tank, and by location of the opening 212 at the forward or front end of the reservoir ahead of the steam generating boiler 176, the opening 212 will be above the water level in the reservoir in the side rest position illustrated in Fig. 10 and also in the corresponding opposite side rest position.

In order to limit the total volume of liquid which may be placed in the reservoir to a volume which will remain below the opening 212 when the iron is in one of its side rest positions as shown in Fig. 10, we have shown a filling plug opening at a level below the top of the reservoir as shown in Fig. 4 and Fig. 7. Thus a portion of the top of the reservoir is downwardly offset as shown at 274 and this portion is provided with a threaded filling opening 276. A filler plug 278 is provided with a threaded body portion 280 adapted to fit the opening 276 and close it when the plug is in position.

When the plug is removed for filling the reservoir, it is apparent that the maximum levels to which the water in the reservoir may be raised, assuming the iron is in the horizontal position of Fig. 7, is the level defined by the upper surface 282 of the recessed portion 274 in which the filling plug is located. Since the forward portion of the tank is vented, iiquid may be filled up to the point where it reaches this level as shown at 284 within the reservoir. The addition of any further liquid will simply result in the liquid running over the edges of the filling opening.

The extent to which the surface 282 must be recessed below the top of the tank is determined by the exact location of the opening 212 through which water passes from the reservoir to the boiler. In general, however, it will be apparent from the teachings of this application that the volume of the air space remaining at 286 above the liquid level in Fig. 7, must be equal to at least the volume of the air space at 288 in Fig. 10 above the maximum possible liquid level in the side rest position.

It might be noted at this point in connection with Fig. 10 that this level is preferably chosen so that not only is the opening 212 located above the liquid level in the rest position, but also the venting opening where the valve stem 214 passes through the top of the reservoir will be above this level. This vent opening location is shown in Fig. 4 at 290. Thus, when the iron is tilted to the position of Fig. 10 or to its corresponding opposite position, no liquid can enter the opening 212 to add to the supply of liquid in the boiler 176, nor can any further liquid enter in the vicinity of opening 290 to flow out through the vent tube.

It will be noted in connection with the filling opening 276 and plug 278, that the particular location of the rccessed surface 282 is in the vicinity of the side rest 238. In order to provide ready access to the filling opening, the side rest is cut away above the filling opening as shown at 292, and in this respect side rest 238 differs slightly from side rest 236. The supporting edge 294 of side'rest 238, however, is substantially identical to the corresponding edge 272 of side rest 236, and their angular orientation is complementary as discussed above in order to insure the desired elevation of the front portion of the iron in either of its rest positions.

By virtue of the features just described, it is apparent that the supply reservoir will remain vented in either the operating or rest position, without loss of fluid, and that communication between the reservoir and boiler through the conduit 204 will be automatically cut off or re-established in response to movement of the iron to or from its rest position.

According to a further feature of the preferred form of the invention, means have been provided to insure'thc cessation of the boiling action within the steam generating boiler and also to prevent inadvertent loss of liquid through either the steam tube of the boiler or through the vent tube at the front of the iron. In connection with the boiler, if steam ironing operation isbeing carried out before the iron iis moved'toitsfiresttposition, there'will be alimited predetermined volume of water within the boiler port-ion 176 at-the time the iron ismoved torest position. Thus evenathoughthe further: supply of liquid is in terrupted, in themanner described above, we have'found itdesirable '10 make some provision for the liquid already inthe-boiler.

For this purpose, =we 'have selected the rest position as shown-in-Fig. 8, so that in that position the upper portion of the-boiler or steam dome 190 will be somewhat lower than the hot steam 'gge'neratin'g surface 162 at the bottom of theboiler; The liquid within theboiler is'then automatically removed from-tl1e heated boiler surface and carried to'the unheated end-of-th'edome 190 as shown at- -296.--

According to the invention, we have also located the upper end of thesteam conduit tube'166'within this upper or second-portionofthe steam generating boiler at a -pointwhich is-above the lev'el of the liquid at 296 when the iron is in its rest position". In other words, even though the ironwere filled, as far as permitted by thefilllimitationmeansdiscussed above, and even though the'iron were then tilted immediately to its rest position, the maximum amountof Iiquid for' which the boiler is designed couldbe accommodatedin the p'ortionof the dome 1'90be1ow the end-of the steam conduit166 in the rest position.

In-order to reducethe size of the steam dome at this pointand permit the use' of smaller parts with consequent economy of manufacture, we havemade provision as discussed-earlier'inthis application for substantially restricting the total volume'of water in theboiler. This restrictionis obtained bymeansof the annular sleeve 186 andthe narrowed'section 176 of the lower portion of the boiler. The invention thus contemplates the careful correlation'of theyolume of liquid in the boiler with the size and sh'apeof-the-steam dome portion whichlies below the steam conduit tube "166 in'the'rest position, in order to achieve the objectivesjust discussed.

' Furthernioregthe provision of the insulation at 180 between the "steam generating'areal62 of the solep'late and the remainder of the boiler prevents the rapid transfer of heat to the upper portions of the boiler and thus insures that these'portions'will be cool enough tostop the steam generation" at the appropriate point. The boiler walls' and I dome may also 'be':- made of material of lower thermal conductivity,-.for' this'same purpose, as, for example, stainless 'steel.

As illustrated in Fig. 9, it-m'ay sometimes happen thatat the instant the iron is tilted to'its r'e'st'position, there-may be some" water trapped in the valve chamber 210"and therem'aybe at'endncy for this liquid to pass alo'ngthe valve stem andintodhe vent tdbe as the iron is tiltedto the rest p'ositionof Fig. 9. For'this purpose, the'vent opening 232 has been spaced a substantial distancefronrthe normal upper end 228' of the vent tube. Thus any liquid'which might be trapped in this manner can be accommodatedas shownat 298 Without loss of such liqui'd through theop'e'nin'g 232 in"the'rest position.

The-preferred embodiment of Figs. 4-10 thus co'nstitutes a device which may be' used-s'electively as a steam or dr-ydron; Its'fsteamin'grat'e be adjusted for steam pressing.zof diherent fabrics byvariation of the soleplate temperature under the cohtrol'of the manually adjustable thermal switch, without the use of special liquid metering valves or'orifices'. The generation of steam is automatically interrupted-in an improvedmanner when the ironismoved to either of its two rest positions both-by removal of-liquid to a cooler portionofthe steam genera-tingichamber and by interruption of the liquid supply to such chamber. Special features of'constructionpreventthe loss of liquid from either' the reservoir or boiler chamberwhen the iron is in arest position.

--The-combinations of elements and features of-consti'uction which have been described in-connection with the --:foreg'oingembodiments :thus make possible the productionof a 'steam iron which substantiallyaccomplishes the objectives set forth at the beginninglof thisspecifica= tion. Since minor variations and changes of construction' will be apparent to persons skilled in this field, it is intended that this *in ention'shall cover all such changes and modifications as fall within the spirit and scope "of the attached claims.

Now, therefore,-.we' claim: a

1. A steam iron comprising a soleplate having top and bottom surfaces, a reservoir above said 'soleplate'for containing water therein at a: predetermined-maximum level electrical heating means for the soleplate, means provid ing.;a steam' generatmgboiler chamber defined by wall portions' having their lower ed'ges in sealing engagement aroundthe edges ofa relatively small predeterminedcom stant area'of said top surface and their upper edges above saidpredetermined water level, and means norrnallymaintaining .a predetermined small volume of liquid in' the boiler chamber with'porti'ons of the liquid covering the entire soleplate top surface area within the chamber throughout normal ironing-movements for generation of steam in-the presence of'such liquid by heat-conducted from the' heating means to the liquid throughout said pre'-' determined soleplate top surface area, said last-mentioned means including meansconnecting said reservoir and said boiler chamber for maintaining the liquid level within saidboiler chamber at least as high as that within said reservoir, and steam-conduit means having one end communicatingwith said boiler chamber at a point above said predetermined maximum water level and having another'end located to discharge steam on the material to be ironed by said bottom surface of the solepla'te.

2. Asteam ironaccording to'clair'n 1 in which said predetermined area is less than substantially one square inch.

3; A steam iron'according to claim 1 in which said predetermined area of said soleplate upper surface at the bottom of the boiler chamber has an area less than substantially 1 of the'total area of the soleplate bottom surface.

4'. A steam iron according to claim 1 having adjustable control means for-the heating means for supplying heat energy'equiva'lent to at least fifty percent of the total wattage consumption of the ironto said predeterminedarea of the'upp'ersurface for'generation of steam during steam ironing operation.

5. A steam iron accordingto claim 1 having adjustable control means for the heating means for supplying heat energy at the rate of substantially 250 to 600 watts to said predetermined area of the'upper surface for gerieratio'n ofste'ain during steam ironing operation.

6. A steam iron'according to claim 6 having the soleplate constructed of material having a thermal con ductivity in the range from substantially 0.24 to 1.0 meastlredin c. g. s. units, and adjustable'control means for the heating means for maintaining the soleplate at any one of a plurality of pre-selected temperature in the range from substantially 325 F. to 450 F. during steam" ironirig' operation, and the size of said predetermined area of the'top' surface being in the range from substantially 0.7 to' 0.9 sq'uareinch.

7. In a steam-iron comprising a soleplate havin top andbotto'm surfaces, heatingrneans foi: said sole'plate, and a water reservoir above the soleplate having means for limiting the filling of the reservoir to a predetermined maximum water level, theimprovement comprising a steam generating" boiler adapted to contain a limited volume of water at all times during operation and having a'lower' portion in direct heat-conducting relation with a predetermined area of said top' surface close to said heating'means for boiling said water by heat from' said area, said boiler extending upwardly above said maximum reservoir water level, steai'nconduit means having one end opening into said-boiler aboVe'said-maXinium' Water level andhaving its other end open to atmosphere at a point adapted to discharge steam onto material ironed by said bottom surface, means normally venting the reservoir to atmosphere at a point above said maximum water level during steam-ironing operation, and a water conduit connecting the water-containing portions of the reservoir and boiler during operation, said water conduit having a relatively large cross-section throughout its length, and the combination and relative location of said water conduit, venting means and steam conduit means automatically maintaining essentially the same water level in said boiler as in said reservoir throughout such operation.

8. A steam iron according to claim 7 having valve means controlling said water conduit and being manually operable between either one of only two positions consisting of a first position in which the conduit is completely open for rapid equalization of boiler and reservoir water levels throughout steam ironing operation and a second position in which the conduit is completely closed for dry-ironing operation or storage, and said steam conduit extending downwardly from said one end, through the water in said boiler and thence directly to said other end, thereby maintaining the steam temperature in said conduit means close to the boiling temperature of the Water for discharge onto said material.

9. A steam iron according to claim 21 having means selectively supporting the iron in a rest position in which a portion of the steam generating boiler is located below said predetermined area, said portion having a volume greater than the maximum volume of liquid maintained in the boiler during operation in ironing position, movement of the iron from operating to rest position thereby automatically removing all the liquid from said predetermined soleplate area and stopping the further genera- 5.

tion of steam.

10. A steam iron according to claim 9 having means substantially reducing the free cross sectional area within an intermediate region of the boiler chamber just above the soleplate area and thereby limiting the volume of liquid in said chamber to an amount substantially less than the product of said predetermined soleplate area times the depth of liquid above said area.

11. A steam iron according to claim 10 in which the free'cross sectional area at normal water levels within the region above the soleplate is not more than of said predetermined soleplate area.

12. In a steam iron comprising a soleplate having top and bottom surfaces, heating means for said soleplate,

and a water reservoir having a bottom spaced above the soleplate top surface in poor heat conducting relation therewith and having means for limiting the filling of the reservoir to a predetermined maximum water level, the improvement comprising means defining a separate steam generating boiler chamber having its bottom in direct heat transferring relation to a predetermined portion of said top surface close to said heating means, said boiler.

chamber extending up through said reservoir to a point substantially above said maximum reservoir water level, steam conduit means having one end opening into said boiler chamber above said maximum water level and having its other end open toatmosphere at a point adapted to discharge steam onto material ironed by said bottom surface, means normally venting the reservoir to atmosphere at a point above said maximum-water-level during steam-ironing operation and a water conduit connecting the bottom of said reservoir and said boiling chamber during such operation, said water conduit having throughout its length a cross section substantially greater than that required for replenishing the water converted to steam in said boiler and the combination and relative location of said water conduit, venting means and steam conduit means automatically maintaining essentially the same water. level in said boiler as in said reservoir throughout such operation.--

13. A steam iron according to claim 12 in which said steam conduit extends from said one end downwardly within said boiler through the liquid therein and thence directly through the soleplate with said other end of the conduit opening at the bottom surface of the soleplate, the relative location and length of said conduit thereby maintaining the steam close to the boiling point of the water in said boiler for discharge onto said material.

14. A steam iron according to claim 13 in which said soleplate bottom surface has a plurality of open grooves communicating with said other end of the steam conduit, the ends of at least a portion of said grooves opening to atmosphere through the soleplate above the plane of the bottom surface and thereby venting the steam conduit to atmosphere even when said grooves and conduit are partially blocked by the material being ironed.

15. A steam iron according to claim 14 in which the total cross-section of said grooves opening through the soleplate is substantially as great as the cross section of said steam conduit.

16. A'steam iron comprising a soleplate having a central longitudinal axis, a steam generating chamber heated by the soleplate, a liquid reservoir above the soleplate, a water conduit connecting the chamber and reservoir for flow of liquid from the reservoir to the chamber during steam ironing operation, supporting means constructed and located to support the iron selectively in either of two side rest positions in which the iron is tilted to one side or the other around said axis with one and the same predetermined end of the soleplate axis higher than the other end of the axis in each of said side rest positions and with the soleplate rotated at least substantially around said axis from its normal ironing position, and means automatically interrupting the flow of liquid through said conduit in response to movement of the iron to each of said rest positions, said last mentioned means including the location of a portion of said conduit at a point below the normal operating liquid level in said reservoir, said point being located along said axis near said one predetermined end, and means limiting the maximum normal volume within said reservoir to an amount which is accommodated below said point in each of said side rest positions.

17. A steam iron comprising a soleplate having top and bottom surfaces, heating means for said soleplate, a steam generating boiler having a lower first portion in direct heat-conducting relation with a predetermined area of said top surface close to said heating means and an upper second portion located above the first portion in the normal operating position of the iron, means thermally insulating said upper portion from said lower portion, means for maintaining a limited predetermined volume of liquid in said boiler during ironing, steam conduit means having one end opening into the upper portion of said boiler above said liquid and having its other end opening at a point adapted to discharge steam onto material ironed by said bottom surface, and means for supporting the iron in a rest position in which said second portion of the boiler is below'said first portion of the boiler and the liquid in said boiler is gravitationally shifted to the thermally insulated second portion, the volume of said second portion located below the steam conduit opening in said rest position being greater than the maximum predetermined volume of liquid in said boiler.

References Cited in the file of this patent UNITED STATES PATENTS 1,677,819 Faust July 17, 1928 2,295,341 Finlayson Sept. 8, 1942 2,368,048 Stone Jan. 23, 1945 2,425,598 Clum Aug. 12, 1947 2,499,915 Graham et al. Mar. 7, 1950 2,582,773 Finlayson Jan. 15, 1952 2,587,608 Finlayson Mar. 4, 1952 2,668,378 Vance' Feb. 9, 1954 Patent No. 2,837,847

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Edmond CTo Franklin et all,

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 8, line 13, for "combinnation" read me combination column 14 line 53, for the claim reference numeral "6" read 1 column l5; line 27, for the claim reference numeral "21." read me '7 e Signed and sealed this 26th day of August 1958 (SEAL) Attest:

KARL H. AXLINE Attesting Officer ROBERT C. WATSON Commissioner of Patents

Images