US2408886A - Electric iron - Google Patents

Description

F. w; SCHARF ELECTRIC IRON Oct. 8, 1946,

4 Sheets-Sheet l Filgd Nov. 1, 1941 u M Tmi \lllc INVENTOR. FRANK W. Sa/ARF ATTO EY Oct. 8, 1946.

F. w. SCHARF ELECTRIC IRON Filed Nov. 1, 1941 4 Sheets-Sheet 2 Q Q A.

u 7/ Hm INVENTOR. FRA K SCHARF ATTORNEY F. W. SCHARF ELECTRIC IRON Oct. 8, 1946.

Filed Nov. 1, 1941 45heefcs-Sheet 3 R 8 0A mm.w ww m T k Z M 2,40s,sss

F. W. SCHARF ELECTRIC IRON Filed Nov. 1, 1941 4 Sheets-Sheet 4 INVENTOR. FRANK W. Sommn/mM ATTORNEY Patented Oct. 8, 1946 -ELECCITRIC IRO N Frank W. Scharf, San Gabriel, Calif assignor to McGraw Electric Company, Elgin, 111., a corporation of Delaware Application November 1, 1941, Serial' No. 417,437

13 Claims. 1

My invention relates to electric'sadirons.

An object of myinvention'is to provide an electric sadiron having means -toreduce the amount of heat reaching the housing from the soleplate.

Another object of my invention is to provide means for supporting the housing and the "handle by common means supported from the rear end of the sol'eplate.

Another object of my invention is to provide-a common means for supporting the heater terminals, a heater control switchga housing and a handle for a sad'iron, said means being secured to the heated body or to the sole'plate of an electric iron and being made of relatively poor'heatconducting material.

Other objects will either be apparent from a description of one form of device embodying my invention or will be pointed out in the course of a description thereof and set forth more particularly-in the appended claims.

In the drawings,

Figure lis avertical'longitudinal sectional view through an iron embodying my invention,

Fig. 2 is a plan view'of the top of the heated body, taken on the lines 22 of Fig. 1,

Fig. 3 is a fragmentary vertical section taken on the line 3'3of Fig. 2 to show the method of crimping the heating elements into the soleplate,

Fig. 4 is a fragmentary substantially vertical sectional view taken onthe line 44 of Fig. 1,

Fig. 5 is a'plan'view of one of .the heating elements,

Fig. 6 is a side view of the device shown in Fig. 5,

Fig. '7 is a fragmentary sectional View on the line '!'I of Fig. 2,

Fig. 8 is a fragmentary sectional plan 'view taken on the'l-ine 8-8 of Fig. 9,

Fig. 9 is a vertical longitudinal fragmentary sectional View similar to Fig. 1 except that the switch contacts are shown in closed position to produce a minimum soleplate temperature,

Fig. 10 is asubstan'tially horizontal sectional plan view'on the line 10- 10 of Fig, 11,

Fig. 11 is a view similar to Fig. 9 and the contacts'are shown in clo'sed position to produce a maximum soleplatie temperature,

Fig. 12 is a diagram of the electrical connections of the heating elements and of the control switch therefor,

Fig. 13 is asubst'anti'ally vertical sectional view taken on the line -I 3'l3 of Fig. 1,

'14. is a top plan view of a skeleton frame,

Fig. .15 is a front view of the device shown in Fig. 14, and,

Fig. 16 is a side view of the skeleton'frame of Fig. 15.

An electric sadiron, designated generally by numeral 21'and embodying my invention, comprisesa relatively'thin so-leplate 23 and while this may be made of ironor steel, I prefer to make it of high heat "conducting material such "as brass or copper, but my invention is not limited particularly to the material of the soleplat'e 23.

The soleplate '23,'whi'chis shown as of 'substan: tialiy triangular section to provide a form now usually used for electric-sadirons, is provided with a plurality of depressions or recesses 25 in its upper-surface, which recesses o'r depressions are preferably made circular'so'that it is relatively easy to provide suchrecesses as by drilling or machining the same to the desired depth, Each of these recesses has located therein an electric heating element '21 which heatingelements individually comprise an intermediate "substantially circular piece of thin electric insulatingmaterial 29, su oh 'as mica, having recesses over a part of itsopposing outer periphery, as will be noted from Fig. 5, to permit of Winding 'thereon a resistor strip SI of a suitable material to -be traversed by the heating current. I provide further two outer sheets 33 and 35 preferably of mica, positioned against the upper and the lower surfaces of the intermediate sheet 29, to permit of locating the resistor comprising the strand 3| in one of the recesses 25.

The terminal leads 3! from eachof the heating elements may be made of increased current-carrying capacity as by doubling over the end portions of the resistor strand 3! and'I prefer to provide a bushing 39 for each terminal lead. I may make this bushing of any suitable refractory material which has the characteristics of electric insulation as well as high temperature resistance since a heating element of this kind will cause a temperature on the order of 500 F. to 700 F. or even moreto'occur. Each bushing 39 is provided with a lower or inner end portion of increased diameter such as is possessed by the usual Wood screw.

Each heating element'is held in one of the plurality of recesses 25 by a 'thin'shee't of metal 4| which. is of substantially the same diameter as that of the recess '25 and may even be initially of slightly greater diameter to necessitate a pressure being applied thereto to force it into the recess 25 whereby a relatively low thermal reluctance heat path is provided between the the plate 4| will remain in its proper operative position in close engagement with the upper surface of the electric heating element, I may crimp or swage the adjacent wall of the recess 25 over against the outer peripheral portion of the member 4| as is shown at 43 in Figs. 2 and 3 of the drawings, and while I have shown four such crimped portions, I do not desire to be limited thereto.

The terminal leads 3'! of the individual heating elements may be located on the mica sheet 29 at substantially diametral points and may be connected as by a connector 45 in any suitable or desired manner, an additional sheet 41 of mica being located between the engaging pair of terminal leads 3! to thoroughly insulate them against accidental contact with either the soleplate 23 or the member 4|.

I provide a pair of terminal members 49 and for the plurality of electric heating elements hereinbefore described and mount them respectively on supporting beams 53 and 55. These supporting beams are provided with portions extending at substantially right angles to each other, as shown particularly in Fig. 1 of the drawings, one of these portions extendin substantially vertically as indicated by numeral 51 while the other portions may be part of the substantially horizontally extending inner end of the beams and are indicated by numeral 59 in Fig. 2 of the drawings. A plurality of screws may extend through members 51 and 59 and into the rear end portion of soleplate 23 and it is to be noted that the beams 53 and 55 extend rearwardly of the rear end portion of the soleplate 23. As will be noted from Fig. 2 of the drawings, the terminal members 49 and 5i hereinbefore referred to are insulatedly supported on the two beams. I wish to point out here that I prefer to make the supporting beams of a material which has a high thermal reluctance and for illustrative purposes I may mention that the so-called stainless steel may be used by me for such purpose. I may also point out that a plurality of perforations 6| may be provided in the wall of the beams in order to reduce the heat-transmitting area of these beams.

I provide a shell or housing 63 to cover the heated body by which I desire to have it understood that I refer to the soleplate and the heating elements swaged therein as hereinbefore described. This housing 63 is of usual hollow shape. on the interior, and is provided with a raised rear end portion 65, as will be seen by reference to Fig. 1 of the drawings. The upper surface of the rear end portion 65 slopes downwardly and backwardly and its rear edge portion 6! is preferably spaced apart from the ironing surface of the soleplate 23, that is, from the horizontal level of the ironing surface an appreciable distance, as is well known in the art.

I provide a skeleton frame 69 (see Figs. 14, and 16) and I prefer to make this skeleton frame of a shape combining connected portions of relatively small area of cross section and further to make this skeleton frame of "stainless steel in order to increase its thermal reluctance. Generally speaking, the skeleton frame 59 may include two lower flat portions Ii and 13 and upper spaced parallel extending portions 15 and 11 with integral connecting webs between the respective portions H and 15 and I3 and 11, together with a cross bar 19. I wish to here point out that wherever possible, particularly in the webs hereinbefore mentioned, I may provide a plurality of openings 8| in order to decrease the heat trains- .4 mitting area and it is to be noted particularly that the openings reduce the area of the webs connecting the lower members H and 13 with the upper members 15 and 11, all as will be noted by reference to Figs, 14, 15 and 16.

The members H and 13 are adapted to be secured to and supported by the beams 53 and 55 respectively, heat-insulated washers 83 being placed therebetween, bolts or screws 85 and nuts thereon being provided to tightly clamp the washers 83 between the portions H and 13 of the skeleton frame and the beams 53 and 55 of the supporting beams.

It is to be noted that the upper surface, and particularly the members 15 and H of the skeleton frame, slant downwardly and rearwardly to cooperate with the rear end portion 65 of the housing.

I provide further a, composite handle which includes an inner metal skeleton frame 81 which is preferably made hollow and as light as con sistent with the desired strength and surround at least a portion of this handle frame 91 with a handle 89 which is preferably made of heatinsulating material such as a moulded plastic composition. I may provide a further support for the combination handle in the shape of a strip 9! of metal of suitable or pleasing form having its lower end secured against the outer surface of the shell 63 as by a machine screw 93 while its upper end may be properly or suitably interfitted with the front end portion of the handle member 81.

At the rear end of member 81 I provid substantially horizontally extending flanges 94 at each side laterally of the handle and I provide also suitable openings 95 in these flanges through which a common securing means, indicated by screws 91 in Fig. 1 of the drawings, extend to clamp the handle against the outer surface of the rear end portion 65 of the housing and the housing against th upper surfaces of members or portions 15 and 11 of the skeleton frame. I provide an additional machine screw 99 at the front end portion of the rear part of the handle member 81 extending through the housing portion 65 and into the front portion of the flange members 93, as shown more particularly in Fig. 1 of the drawings.

The cross member 19 of the skeleton frame 89 has insulatedly mounted thereon a pair of contact members I9] and I03 which are adapted to be engaged with a thermally-actuable 'contact bridging member I05. Further, these terminal members are connected in electric circuit with one of the hereinbefore described heating elements and with one of the terminals of the switch, all as shown in Fig. 12 of the drawings. A twin conductor cord I0! is provided extending outwardly through a, rear end portion I99 of member 89 of the handle.

I provide a bimetal bar III in a recess H3 adjacent the rear end portion of the soleplate 23, this bimetal bar being secured to a portion of the soleplate 23 in the recess H3 as by a, rivet or screw I I5 and I may provide a cover member H1 above the recess H3 held by a small machine screw against the soleplate 23 in order to properly protect the bimetal bar.

Mean for operatively mechanically connecting the contact bridging mem'ber I05 with the bimetal bar Ill may comprise a linkage including two parallel extending spaced bars H9 and IZI connected by a cross plate I29 pivotally supported on the inner and front end portion of the skeleton frame '69 by jpivot pins I22. Thelinkage includes further a rearwardly extending arm I23 of substantially L-shape having a .longer substantially horizontally extending arm pivotally mounted to bar I I 25 connecting the two arms 'I I9rand I'ZI .I provide further a central arm'I2'I integral with thetwo arms H9 and I2I, this arm extending rearwardly and upwardly through an aperture I29 in portion 65 of the housing. I provide a manually-actua'ble arm I3I .ipivotally mounted :on a side portion-of the rear rend portion I55 of the .shellyapivot screw I33 permitting of manual movement of arm I3I from the positiontshown in broken lines in FiguB of the drawings't'o the position shownin'fulllines in Fig. of the drawings. The-arm I:3I is connected'with arm .12! by a hooked link I35.

A spring :member I31 of U-shape and made preferably of a spring wire, is so constructed and appliedrto pivot .bar I25,"toa pin I39 in arm I21 and to one of the arms of bell crank lever I23, as to cause bell crank lever I23 to move in -a clockwise direction or, in other "words, to bias lever I23 in a direction to cause "engagement between contact bridging member I05 and contact members MI and I03.

Bell crank lever I23 has depending therefrom a bar I M pivotally connected with arm I23 and extending through an opening I43 in member I I! to either be in engagement with bimetal bar I initiallyorduring theoperation of the iron with the object of causing disengagement of contact bridging member I05 from the, fixed contact members ml and I03 when the sole plate is heated .to a predetermined temperature. be'n'oted that when manually-adjustable arm I3I has been moved to substantially one of its limiting positions, as shown by broken lines'in Fig. 8 of the drawings, arm I21 has been turned in a counter-clockwise directionas have also arms I I9 and I2I, on pivot pins I22. The result is that member I 41 has been moved downwardly and may have been moved into engagement with bimetal bar I II :and contact bridging member I05 may have beenmoved out of engagement with contact members IIII and I03.

If arm I3I is moved by the operator in aclockwise direction, as seen in Fig. 10, arm I21 and the members H9 and I 21 integral therewith will be turned in a'clockwise direction on the :pi-vots I22. The rod I25 will .ialsobe turned onzthe pivots I22, which movement, in combination with the action of the spring I31, .causes a'pivotal movement of arm I23 iaroundmember I25 and also around the pivotpin "at the upper end of rod I4I This motion willcontinue until thebri'dging member I05 engages contacts I01 and I03, as shown in Fig. 9, .after which further movement of farm I21 in a clockwise .direction causes arm I23 to move as an integral "part of members I21, I19, I and I2I. The engaging surfaces of bridging member I05 and contacts IN 'and I03 are radial around the pivot points I22, so that continued movement of arm I2I will cause these surfaces to move over this radius with the result of an upward movement of rod I4.I as shownin Fig. 11. While these parts are in any oneof the positions of Figs. 9 and 11 or intermediate therebetween, an upward movement of rod I4I because of upward flexing of bimetal bar .III will cause ia'rm I23 to move counter-clockwise around the pivot I against the bias of spring I31 to disengage the contact bridging member I05 from thecontacts I-0'I and I03 itoiinterrupt the 'energizingicircuit.

It may The operating temperature of a shell or housing =on.an electric iron-is,'in general, determined by the amount-of heat which reaches it eitherby conduction, by convection currents of air, or by radiation from the heated body of an electric iron, it being obvious that such heat will beradiatedxfrom or otherwise'disposed of by the shell or housing such as by convection currents of air striking the housing, particularly while it'is fibeingmoved back 'and forth as in ironing,'a'nd the temperature is, of cours'eyfixed by thecondition's of heat radiation :from the housing and the heat otherwise-lost therefrom as noted above.

It is, therefore, highly desirable to reduce the amount of heat reaching the shell from the soleplate or 'heated'body and it will be noted, particularly from Fig. 1 ofithe drawings, that the shell 63 is notin direetheat-conducting engagement with the soleplate 23. I prefer to providean appreciable gap between the .lower peripheral "edge of the housing -63 and the "adjacent upmr-"surface of the outer peripheral flange of the soleplate 23 to permit'of some convection currents "of'air from the outside flowing therebetween. Heatradiated from the otherwise uncovered 'upper's'urface of the heated body of an electric sa'diron causes an appreciable 'rise of temperature of the covering housing and in order to reduce the amount of heat radiated by the soleplate 23 against the inner surface of the housing '63, I provide a heat-insulating shell I 41 between the upper surface of the Soleplate 23 or of the heated body and the inner surface ofthe housing 63. This heat insulating cell comprises a band or strip I49 preferably made of a metal or alloy'having a relatively high thermal reluctance, formed into a substantiall V-shaped member corresponding to the general outline of the soleplate and of the housing. I provide a plurality of cross bars 148 secured thereto and extending laterally of the iron 21. I provide further an upper skeleton frame I5I also of substantially V-shape'having its front end connected with the front end of the band I49 by a short rod I53. The rear end portions of member I'5I extend angularly upwardly to be secured against two front surfaces of skeleton frame 69 as shown in Figs. 1 and 13 of the drawings, two short'machine screws or bolts I55 being provided to hold the frame I 5I "and the band I49 in the desired operative position substantially parallel with the upper surface of soleplate 23 and spaced therefrom at all points thereof. The rear end portions of the arms of member I5I may extend downwardly as shown byrnumeral I51 in Figs. 1 and 13 of the drawings to have their lower end portions suitably connected to inwardly extending rear end portions of member I49.

I provide a lower sheet I59 of thin sheet metal, such as aluminum. and usually called Alfoil, and I provide further an upper sheet IIiI of a similar metal, the characteristics of which are that it is highly polished to resist the reception of radiant heat and that :its mass is relatively small. The two sheets I59 and I61 are spaced apart an appreciable distance, as shown in Fig. 1 of the drawings, to include a volume of air therein or therebetween and :it is evident that such heat-insulating shell will be highly effective to .prevent heat radiation of any appreciable magnitude from the 'soleplate 23 ;to the housing 63. It is, of course, obvious that the sheets I59 and IBI will have openings provided therein through which rod I'4TI may extend.

I provide a bottom closure plate I68 which is adapted to be secured as by machine screws [65 against the rear edge portion 61 of the housing. I provide a plurality of slots I61 in member I53. I provide a plurality of substantially horizontally extending louvers or openings I59 at each side of the rear end portion 65 of the housing.

A thin rod or Wire I'll has one of its ends secured to the inside of the housing near the front end thereof and the lower end of the rod lll extends into a small recess I13 in the upper surface of the soleplate. As will be noted by reference to Fig. 1 the rod I'll does not engage the bottom surface of the recess, since its function is to prevent undue strain on the members supporting the housing, which supporting members operatively connect the rear end portion of the housing with the rear end portion of the soleplate, in case the iron is accidentally dropped on its handle.

The device embodying my invention comprises particularly an initial supporting means for certain parts of an electric sadiron secured to the rear end portion of the iron and extending backwardly thereof and adapted to reduce the flow of heat from the heated body or soleplate of an iron to the means supported thereby.

I provide further a common means for supporting a thermally actuable switch, heating element terminals, a housing, a handle and a manuallyactuable lever arm adapted to adjust the thermally-actuable switch.

I provide further a common means in the shape of a plurality of screws for holding the handle against the rear end portion of the housing and for securing the housing against a skeleton frame supporting it. My invention provides further a supporting means for the housing and the handle which is made of material having a high thermal reluctance to appreciably reduce the amount of heat conducted from the heated body or the heated soleplate of an electric iron to the housing and to the handle.

Various modifications may be made in the structure embodying my invention and all such modifications clearly coming within the scope of the appended claims shall be considered to be covered thereby.

I claim as my invention:

1. A sadiron comprising a soleplate, heating means for the soleplate, a housing for the iron forming with the soleplate an air chamber, and rigid supporting means supporting the housing in spaced relation to the soleplate and being confined to the local area of the rear end of the iron, said supporting means comprising a pair of spaced supports secured to the rear edge portion of the soleplate and a skeleton frame upstanding from said supports and being secured to the local rear end portion of the housing.

2. A sadiron comprising a soleplate, heating means for the soleplate, a skeleton supporting frame of high thermal reluctance supported by the soleplate and extending outwardly beyond the rear end of the soleplate, a hollow housing for the iron having a rear end portion extending outwardly beyond the rear end of the soleplate and being supported at its rear end portion only and by said skeleton frame and a heat-insulating cell between the soleplate and the housing supported at its rear end portion by said skeleton frame in spaced relation to the soleplate and the housing.

3. An electric sadiron comprising a soleplate, electric heating means embedded in the soleplate, a. hollow housing for the iron having a rear end portion extending outwardly beyond the rear end of the soleplate, a heat-insulating cell between the soleplate and the housing, a bimetal bar on the soleplate, a switch for controlling the electric heating means actuable by said bimetal bar and a skeleton supporting frame secured to the rear end portion of the soleplate and extending outwardly beyond the rear end of the soleplate into the rear portion of the housing and supporting the housing, the heat-insulating cell and the control switch in spaced relation to the soleplate and the housing and cell in spaced relation to each other.

4. In an electric sadiron comprising a soleplate, electric heating means embedded in the soleplate, a pair of spaced supports secured to the rear end portion of the soleplate and extending rearwardly therebeyond, terminal members for said heating means insulatedly mounted on said supports, a. skeleton supporting frame projecting outwardly beyond the rear end of the soleplate and carried by said supports and a thermally-actuable switch for said electric heating means supported on said skeleton frame.

5. A sadiron comprising a soleplate, heating means for said soleplate, a housing for the iron, rigid supporting means supporting the housing in spaced relation to the soleplate, said supporting means being secured and confined to the local rear area of the soleplate and upstanding therefrom to engage the rear end portion only of the housing, said supporting means comprising a skeleton frame, a handle having its rear end support resting on and supported by the rear end portion of said housing and common fastening means for holding the rear end of said handle against said housing and said housing on said skeleton frame.

6. A sadiron comprising a soleplate, electric heating means for the soleplate, a housing spaced above the soleplate and having a perforated rear portion defining a ventilated chamber, and rigid supporting means spacing and interconnecting the housing and the soleplate, said supporting means being confined to th rear end portion of the soleplate and the housing and located in said ventilated chamber.

7. An electric sadiron comprising a soleplate, electric heating means for said soleplate, a pair of spaced beams secured to the rear end portion of the soleplate and extending rearwardly therebeyond, a skeleton supporting frame on said beams, a thermally-actuable switch for said electric heating means supported on said skeleton frame, a housing for the iron supported by said skeleton frame, a handle for said iron having its rear end support resting on the rear end portion of the housing, a manually-actuable lever arm for said switch supported by the rear end portion of the housing and a, heat-insulating cell between the housing and the soleplate having means of high thermal reluctance for supporting it from the skeleton frame in spaced relation to th soleplate and the housing.

8. A sadiron comprising a soleplate, heating means for said soleplate, a pair of spaced beams having high thermal reluctance secured to the rear end portion of the soleplate and extending rearwardly therefrom, a skeleton frame of high thermal reluctance supported by said spaced beams, heat-insulating means spacing said skeleton frame from said beams, a hollow housing for said iron supported by said skeleton frame, said housing having openings in its side and top walls at its rear end portion, a heat-insulating hollow cell between the soleplate and the housing and generally coextensive in area with said housing and means for supporting the cell on the skeleton frame, said cell-supporting means having relatively high thermal reluctance.

9. A sadiron comprising a soleplate, flat heating means in heat conducting relation with the soleplate, said heating means occupying the major area of the soleplate but terminating short of an area adjacent the rear end of the soleplate, rigid casing supporting means secured to said rear end area of the soleplate and upstanding therefrom in horizontally spaced relation to the heating means so as to minimize heating of said casing supporting means by the heating means, said casing supporting means being of lesser width than the rear portion of the soleplate and having its opposite sides spaced inwardly from the side edges of the soleplate, said casing sup porting means being bounded at its front end and at its opposite sides by an air circulating space of substantial depth which extends from the rear end of the iron forwardly over the soleplate and heating means to the front end of the iron and which extends laterally to the side edge areas of the soleplate, and a hollow iron casing overlying the soleplate defining with the sol plate the air circulating space and surrounding said casing supporting means, said casing being mounted on and secured at the rear of the soleplate by the said casing supporting means with the margins of the casing adjacent but spaced from the side edges of the soleplate to provide an opening therebetween for the admission of outside air for circulation lengthwise and transversely through the air circulating space over substantially the entire area of the soleplat and heating means and around the casing supporting means.

10. A sadiron according toclaim 9 further ineluding heat confining shield means substantially coextensive in area with the soleplate but of narrower width than the iron casing, said shield means being secured at its rear portion to and suspended by the upstanding casing supporting means at the rear of the iron, and extending horizontally through the air circulating space in spaced relation to the soleplate, heating means and iron casing,

11. A sadiron comprising a soleplate, heating means located forwardly of the rear end portion of the soleplate, supporting means secured to and projecting rearwardly beyond the rear end portion of the soleplate so as to be subject to minimum heating by the heating means, a hollow housing of greater length than the soleplate and having a rear portion housing said projecting supporting means, said housing being supported at its rear portion only and by a securing connection to said supporting means.

12. A sadiron comprising a soleplate, heating means located forwardly of the rear end portion of the soleplate, supporting means secured to and projecting rearwardly beyond the rear end porti-on of the soleplate so as to be subject to minimum heating by the heating means, a hollow housing covering the soleplate and having a rear extension portion projecting outwardly beyond the rear of the soleplate, said rear extension portion being formed with air openings to define an aerated chamber and said supporting means being located in said chamber, said housing being supported at its rear portion only and by securing connection with said supporting means.

13. A sadiron according to claim 12 further including heat-confining shield means substantially co-extensive in area with the soleplate supported by said supporting means between and in spaced relation to the soleplate and the housing.

. FRANK W. SCHARF.

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