US2461560A - Electric iron - Google Patents

Description

Feb. l5, 1949. w. H. MCLELLAND ET AL 2,461,550

ELECTRIC IRON Filed May 17, 1944 5 Sheets-Sheet 1 ttor-mags Feb. 15, 1949. W H. MCLELLAND ET AL 2,461,560

ELECTRIC IRON Filed May 17, 1944 3 Sheets-Sheet 2 xz m9 az ,40 87 e7 HEAT PosnTloN 'ttornegesA F eb. l5, 1949.

ELECTRIC IRON Filed May 17, 1944 RIGHT SIDE W. H. MGLELLAND ET AL 5 Sheets-Sheet 3 mo la'ld Fig ."l'

Y Invenfbor- WillLcxm H. MCLBllolnol.

ErLclAjczDc ffttornegs.

Patented Feb. 15, 1949 2, 1 n

UNITED STATES PATENT OFFICE ELECTRIC IRON William H, McLelland, Manseld, Ohio, and Eric J. Ajax, Minneapolis, Minn., assignors, by mesne assignments, to Argus, Incorporated, Ann Arbor, Mich., a corporation of Michigan Application May 17, 1944, Serial No. 535,918

17 Claims. (Cl. B19- 25) l 2 This invention relates to improved sadirons of Figure 7 is a cross sectional view along the the electrically heated type and more particulines and in the direction of arrows 1 of larly to improved thermostatic control for such Figure 2; irons and to electrically heated sadiron suo- Figure 8 is an enlarged fragmentary view of a assemblies. portion oi the thermostatic control element in- It is an object of the invention to provide an cluding the manually rotated cam;

improved control capable of operating upon small Figure 9 is a developed view of the cam of the differentials of temperature and of maintaining invention;

the sole plate of the iron at any predetermined Figure 1U is a plan view of the iron showing the relatively constant temperature that may be se- 'fil handle and shell removed;

lected throughout a range of temperatures. It is Figure ll is a cross sectional view taken along also an object of the invention to provide in such the line and in the direction of arrows H il an electrically heated sadiron a manual control of Figure 2;

capable of varying the operating temperature oi m Figure i2 is a cross sectional View taken along the iron and also 0f interrupting the operation of i@ the line and in the direction of arrows l2-l2 the iron. of Figure 2;

It is a further object of the invention to pro- Figure 13 is an enlarged fragmentary view vide an improved thermostatic control wherein illustrating the mode of mechanically supporting the movement of the thermostatic control eleand electrically insulating the electrical contact ment is relieved during conditions of non-operi strips of the thermostatic control element; and ation and distortion of said element is thereby Figure 14 is a wiring diagram of the electrical prevented. heater element, thermostatic control and pilot It is also an object of the invention to provide lamp, an eleetlC Sadil'on Sub-aSSembY Capable 0f bew Referring to Figure l the electric iron of the ing manufactured at low cost from relatively few 1" present invention includes a, Sole plate generally parts. designated ill having a plan contour illustrated Other and further objects or" the invention are in Figures 6 and 10. The sole plate is of metal, those inherent in the apparatus herein illustrated, preferably aluminum or aluminum alloy and described and claimed. preferably plated with a bright coating so as to The invention is illustrated with reference t0 provide a mirror-like ironing surface. The sole the drawings in which Corresponding numerals plate is cnamfered about its outer edge as illusdesienate Corresponding parts and in which tra-tec. at sa. Upon the so1e plate there is moon-Lr Figure l is a side elevational View oi the eleced a rearwardly extending skirt il which is attrically heated sadiron of the present invention; tached in place by a pair of screws l2-I2 as Figure 2 is a side elevational View, partly in .'v illustrated in Figure l0. Skirt H is shaped so section, the sectioning being along a longitudinal as to have protuberances IB and l1 on it.

center line of the iron showing the thermostatic Upon the sole plate and skirt l i there is control elements in the high temperature condi- @mme/gd a. shell generally designated ld having iOl'l 0f OPGIeDOll, but With the iron Geld, es When a smooth downwardly extending contour as lllusdisconnected from the newer source; so traced in Figure 1 and the sectional views,

Figure 3 is a side elevational view broken away Figures 7,11 and l2. The shell may be provided at WO leVeS and partly in section indicating the with an indented rib l5, ii desired, for decorative interior construction of the iron; and stiffening purposes. The upper portion of o. .Figure 4 is a fragmentary side elevational view, he shell is shaped as illustrated in the sectional partly in section, showing the thermostatic coni5 lviews?, i and-lli and includes marginal ilat areas tr'ol elements in the Vcondition in which a rela- SE, a raised centralarea ll and a central longitively low temperature of sole plate operation is tudinal rib 2i. lThis portion of the shell is covermaintained; e ed by a plate generally designated 22 having a Figure 5 is a view corresponding to Figure 4 smoothly curved upper surface 24 and a narrow except that the thermostatic control element is 50 al dat edge 25. The shell has down-turne` shown in the oli condition (circuit interruptapertured protuberances Ee, as illustrated in ed) Figures 5 and 1l, two such protuberances 'it being Figure 6 is a View on the line 5 5 of Figure 2 provided at the rear portion of the iron and with the handle removed and the holding screws another pair provided at 21 near the rear end of andjunction block in section; the plate. The protuberances serve to space the so as to provide space vfor the junction block edges of the plate a uniform distance from the marginal flat portion i3 of the upper surface of the shell l, the center of the plate 22 being also held in'spaced relation with respect to the main body of the shellV by contact with the rib which runs lengthwise. along the top .of the shell. Near the front oi the plate thereis la idcwnmturried rib 28 which li :ewise serves as a spacing. Rivets 25 and 2l are provided through the apertures in protuberances 26 and 2l, and as a result the plate is held rinly assembled on the upper-part of the shell.

The forward end of the plateisprovirledwith an insulated pilot lamp soohetfilllcontaining `pilot lamp 3F. The two wires 3l fandafiiserving ,the

' pilot lamp extend between the upper portion 2% of the shell and the cover plateythe wiresbeing maintained in spaced relation by the central :rib 2l. Preferably the wires are covered with a somewhat soit insulation which is of a diameter such 'as to be slightly Vcompressed and thereby lightly held'between'the shell lil and 'theplate 22 when the parts are assembled together.

,Atthe reare'ndof the platellZ there is mounted a terminal block generally designated having threeterminals, 35 and 3l' thereon, the pilot lamp wires and '3l being connected toterminals 33 and 5l, respectively. The terminal block 3 is heid in place on the cover plate .22 by meansV of. a screw 38 which is threaded ntV .the cover plate. The terminal bloot: is provided with three down-turnedY tubular vtips lill, il and which extend through spaced apertures in .the plateiZZ and the shell'll into the interior ol" the shell. The terminalrblock and'tips 9, lll'andrli areapertured and serve as insulating 'conduits for .the threexconrrection wires sie, @E and ildtothe thermostatic .control elernentand electric asl hereinafter described.

Upon the shell Vthere is 'mounted fa 'handle generally designated i3 vhaving front Ysupport potrion "5S `anda rear support portion ed. The front support portion is provided with a recess which is Vcpm Y'at -thebottom A,of the handle Vand shaped Asoas Yto receive the pilotlarnp'socket and pilot 'lamp-3l) Thev iront support-portion lis also 'provdedrwith ian `aperture 52, vcovered by 'a'decorative'plate' havinga lens 5d therein.

'The :front-support'portion* ilfhas an aperture 5E extending directlyl downwardly from the aperture 52 and `en vattacl'nnent screw AEil inserted through ,the opening 5?. 'into the aperture and is'screwed'througha hole inthe cover plate 2a into a threaded"down-turned boss 'i 'in the shell ldfthus'attaching'the iront part ofthe handle solidlyj-to the shell. lt may be noted thattne Acover plate 53 isheld in place on thefront of the yiron-by means of an inturnedtip'fi and retaining spring *59. The rear lsupport til of the handle d3 visfprovidedwith rearwardly extending side bosses :55 and de which have threaded holes in their. to receive 'a pair of attachment screws and es,

which are insertedirom the-bottom of the skirt yllandextendupwardly through'the shell i@ and Y `then-ce into the threaded'openings in bosses d5 andli, thusifirmlyeattaching the rear portion or" the-handleto the assembly. The rear portion of thehandle is also provided with an Vaperture'lil open-from the bottom of the handle already described, and for the leaddn service wires'l'l and l2. The wires l iV and l?? form a part of 'the electric service cord V'i3 whichenters the -rear'han'dle support tilat the aperture l. 'The service cord 'i3 is' suitably vstrengthened a handle is also provided with a tip tapered rubber section or a coil spring wire support mechanically fastened to the aperture thereby strengthening the service cord where it enters the handle. The rear portion of the 'i5 which serves w h trieprotuberances le and ll on the skirt i! suppertfitheiron whenitds tippedfbaclnwardly.

The foregoing details of construction are .described in greater detail in our copending applications entitled Sadiron assembly Ser. No.

"535,9l9 and Electric iron assembly Ser. No.

535,926, and are illustrated our design applica- ,tion'entitled Electric irons Ser. No. Des. 113,-

63d, nowPatent Des. 139,040 illed concurrently herewith, to which reference is made.

The sole plate iii is provided along its center line with 'a shallow groove is having recesses 'i9 at end of the groove. ln the groove there is fitted a composite thermostatic strip generally designated 8l composed of two pieces Vof relativelystili'metal-having aheat coeilcient'oi expansion different tha-nthatoi the sole plate. lt is immaterial so faras'the present invention is concerned whether the sole has a greater or lesser coeiilolento expanthermostatic'stripgl, but `it ispreto make the sole plate Yoi 'aluminum 'or einem alloy andthe 'composite' therinostatic st l oiron, steel, inver, or similar metal, hailing a losser heat coeilcient of expansionvl than aluminum alloy -oi the-sole of the pieces d2-'and 'ilof the com ponto strip 'has' thickened end e2 and dal which r very convenientlybe merely a washer Yout ironi'the saine niaterialas the' pieces "82 endg-, spot welded or otherwise hrrcly ailixedon the strir The thickened nendportionsfZ andtll of thetwo each has a plan contour such that 1 its neatly into'the recesses i9 andt, and

a result' these thickened lportions serve `as ,chers for theends oi the strips to prevent endnvendent of the strip. The strpsare' held anchored Yends by means voi? screws' S5 Y.- ,hut dueto the factt'hat'th'e end thrust tension on the strips is taken-by the'thiclened ""Dhv *j Vand 'are fitted into theA groove 18 in end.. se relation'with aislight spacel between them, vthe adjacentends of the strips Yare attached means .of 'a spring 'metal loop 9d which is riveted or .otherwiseattachedat' to strip and similarlyriveted or otherwise attached attrito strip i3d.. The loop "t2 is preferablyoa niece of spring steel and is provided'with an anfture'at teinte Vthere is "tted-an insulator. preferably alittle ceramic insulator button Q5.

twill thas be observed that the uppersuriace the soleplate is smooth'(eXceptior,thef'h'eaols crews l2, 'and'll 'since,thegroove'lis by. the composite'thermostatic istrip only .Le loope. protrudes upwardly inthe middle of t-.e Vsole plate. 'Upon the -assembly ci the sole plate and the thermostatic. strip there is positioned a heater element generally -desighated edhaving the shape as illustrated in Figure 14. 'The heater element Yshape Vand. configuration are inoreparticularly described in our copending application entitled Sadiron assembly Ser.

535919 to which reference'is here made, and

type, composed preferably of a pair of superimposed mica insulating panels between which there is placed a mica panel framework on which the electric resistance wire 99, Figure 14, is Wound. The resistance wire 99 is preferably a flat strip of Nichrorne The heating element is suitably provided with a rectangular cut-out along its center line, as indicated at fcc for clearance purposes around the loop Q2 of the thermostatic control, and the heater panel is held in place on the sole plate by means of a pressure plate `generally designated |32, the pressure plate being in turn attached to the sole plate by a plurality of screws |64, as illustrated in Figure 7. The pressure plate is cut away along its center line so as to provide a slot between walls |05 which extends from about the middle part of the iron at wall |06, Figure 2, to the rear portion of the iron. This slot serves as clearance for the loop 92 of the thermostatic strip assembly 8| which extends through a suitable aperture in the heater element 58 into the space between walls |95 of the pressure plate.

Upon the rear center portion of the pressure plate there is mounted a rearwardly extending supporting plate generally designated |08 which is attached to the pressure plate by screws |||l and ll The plate |08 is stamped from metal and is provided with a down-turned edge H3 which serves to align the plate on the outer surfaces of the central bosses H4 and H5 of the pressure plate and thus serves to prevent any lateral displacement of the plate |08 with reference to the pressure plate once the attachment is made by means of screws H0 and l|`|. The

down-turned ange H3 also extends around the rear portion of the plate |08 indicated in Figures 2-5 and adds considerably to the stiffness of this member. Near the center portion of the plate |08 there is provided a rectangular aperture ||6 having upwardly turned side walls ||'7 and H8, Figure 11, that are apertured to receive a through pin upon which a lever generally designated |22 is pivotally mounted. The lever has a forwardly and downwardly extending tip |25 having an insulatingr button V26, preferably of ceramic material, on its end. The rear end |28 of the lever is shaped so as to extend down through the rectangular opening H6 and under plate les as hereinafter dethe tail end of the scribed. The plate |08 also serves as a mounting for a pair of spring contact strips generally designated IBil and |3| which are hung below the plate |08 in a position so as to be located in the slot between walls M15- |05 of the pressure plate.

Referring to Figure 13 it will be observed that the plate |08 is provided with two apertures |34 and spaced along the center line of the plate and a smaller aperture |36 located between them also along the center line of the plate. Below the apertures |34 and |35 there is a rectangular block |37 of insulating material, preferably a ceramic molding having a. circular protrusion |37a and Hilo on its upper surface and circular recesses |37c and |37d in its lower surface. The protrusions .|37a and |371) are spaced so as to fit into the apertures |34 and |35 in the plate |08. Assembed against the block |37 is contact spring |30 and immediately below it there is a terminal connection |40 which extends backwardly and to the right side of the iron (under plate G8), as shown in Figure 10, and terminates in an eye MI, the connection of which is later described. Both the contact strip |30 and the iii) terminal connection |40 have spaced apertures in them aligned with the apertures |370 and |37d in the insulator |37. Immediately below the strip Mii there is assembled another insulator |42 identical with that shown at |37 and the circular protuberances on the top thereof t into the apertures of the terminal |343 and connection |40 and into the recesses of insulator |37, and lock the assembly from moving sideways. Against the bottom surface of the insulator |42 there is assembled a relatively heavy contact strip |115 which is shaped so as to extend backwardly and to the right side of the iron (also under plate |08), as illustrated in Figure i0, strip |45 being provided with a connection screw |47 at its end. Beneath the strip |46 there is assembled the lower spring contact |'3I and both the contact and strip |46 are likewise apertured so as to receive the cylindrical protuberances on the upper surface of a bottom insulator |53 which is identical with the insulators at |42 and |37. Two through bolts |551 and |5I, each having a washer immediately under its head, hold the assembly together, solidly clamped and suspended from the under side of the plate |08. It will be observed that the plate |08 may thus be provided with its contact assembly and with the lever arm |22 as an independent bench assembly which can then be assembled onto the pressure plate and connected.

The plate it likewise serves to carry a pair of binding posts, this being accomplished by providing at each side of the plate S a pair of downwardly and outwardly extending slightly twisted eyes |52 and |53. In the eye |52 there is mounted an insulated terminal upon which the eye 4| of the strip Mil is likewise assembled. The connection wire 45 from the terminal block Si is also connected to the terminal |54. The similar downwardly extending twisted eye |53 at the left side ofplate |08 is also provided with an insulated terminal |53 to which the connecting wire 46. from the terminal block 31|-, and one of the heater element connections |55 is made fast. A low voltage top connection is provided from the heater element at it and extends upwardly as shown .in Figure l2 to the center terminal 35 of the junction block, and serves as a low voltage source for the pilot lamp. The other heater connection is indicated at |57 and is connected to the terminal screw |437 on the stif.F terminal plate |45. Referring to Figures l0, l2 and le, it will be observed that the service supply lines 7! and 72 entering the iron handle at electric cord 73 are connected to terminals 35 and S7. From terminal S5 a lead wire 44 extends downwardly through the insulated tip 40 of the terminal block to the terminal |54 on strip |453 and then-ce through strip |451 to the upper spring contact thence through the contacts to the lower spring contact |3|' and through the stiff contact strip ME to the terminal screw |47 and through the heater element connection |57 to the heater element wire 9S. The circuit continues through the heater element and extends through the heater element lead connection |55 to the binding post |53 and thence through the connection wire it to terminal 37 or the terminal block 34, and thence to supply line 72. The pilot lampsupply voltage connection is made to the heater element at |57. The heater element wire 3S is usually ribbontype Nichrome, and since it operates at red heat, the service connection can be made only with diiculty. However, a serviceable connection at |57 can be accomplished by utilizing a brass wire iiattened outrat the end so as to be of approxipiece oi round Nichrome Wire which is thenattened .throughout its end portion and laid. in Contact with heater element wire Q9 at point 55'?. The wire i655 is brought out of the heater unitand is threaded through the tip fil of the junction block and connectedat center terminal 36. The lead wires i. and from the pilot lamp fili .are brought through holes in the rear part of thevcover plate-t! and, as shown in Figure 12, wire 3l is connected to terminal wire 32 being connected to terminal t7.

Mounting screws il@ (Figure l0) ywhich serve to `Aattach the plate lGS to the pressure plate also serve as a mounting for a Ueshaped spring lli? which extends forwardlyand across the front end portion L25 of the lever v22 as` indicated at HI. The Ispring lle is `t-ensiorued so Ynormally to force the end l2fiV of the lever downwardly, thus bringing the insulated tip l2@ rinto engagementwith the .upper Contact spring i353. The spring lill is .of sufcient strength soas to overcome the resiliency .of the contact spring li. The degree of motion of lever S22, that Vis occasoned bythe resiliency of spring llt, is determined bythe reartip 92S of the lever which'is normally pushed against a cani generally designated H2 by spring VEG. The cam surface H3 is formed on the edge ilange` of the cup-shaped cam member 'i and hase gradually increasing portion H35; of gradually increasing axial width which breaks at the abruptly increasing portion Elb and terminates in a flat portion ilc of uniform axial width.. Figure 9 isa developed view of the cam and illustrates the gradually sloped portion Elsa and abruptly sloped portion H31) and the hat portion Htc. The cam |12 is riveted or otherwise attached to a shaft V55 which extends 'through a hearing member Ill-, the latter in turn being threaded into a threaded, inturned H38 in the plate itil. The position of the cam V52 is such that the cam edge H3 bears against the upper surface of the lever at 52e,

and by rotating the shaft l'l5 the cam 41.3 causes a movement o the end lever E22 up or down, as indicated by the double arrows H9, the degree and .direction of such movement depending upon thedirection and amount or rotation of the cani.

.The cani shaft H5 extends through a hole 23 ,thev shell i4, the washer .being of suicient size so as'to cover the keyhole-shaped opening 2.3. es. illustrated in Figure 2, the hearinaniember lle is `itted on a reduced portion Elliot theshat V55 andthus theshaft 75 is restrainedgfrom end wise movement but is free Ito rotate within the bearing H6. The bearing HE is assembled onto Vthe reduced portion ll'l of the-shaft; the cam i'l2 which ts onthe smal'end H1 o the shaft is then placed on the shaft and Vthe ,end l'l'i is riveted over so as toY holdthe cam i12 `,irnmovable upon the shaft. Y

Thebearing member H6 may b e rotated in the plate. E98 by means of a pair of spaced holes |75 inthe .upper suracecf the bearing membenas llustrated in Eieure l0, A Wrench .ofsutable `cle-- sien yso as tout over shaft H5 andhaving afkey to :fit one or both of holesl llt is applied tothe bearinff and by turning the bearing the cam can be caused to move axially without, however, rotating the cani. Adjustment of the thermos-tatie control can bcaccomplished in this manner. Ai adjustment the bearing H5 locked against rotation by a heel plate 32 which is shaped to overlie a small segment of the rear end of plate ies-and is held in place by a screw 33 which extends through the heel plate and is threaded into lthe supporting plate ich. The segment 182 clamps onto the top surface of the bearing plate ile and prevents its rotation after adjustment. The heel plate E32 is providedwith tip-turned edges llllcand .8219 which serve as stops for .pin ila., which protrudes radially from shaft i'i at a suitable level so as to engage the stops iBZa and' 282i). Access to the locking screw E83 and to bearing plate wrench holes llt can be had even after the iron is fully assembled .by removing knob lSii by removing its set screw. The washer it! can then be lifted oit, and this uncovers the keyhole-shaped opening 23 in theshell .Locking screw 83 is then loosened andthe bearing liti turned by means of a special .wrench inserted through 'hole 23.

In assembling the apparatus the thermostatic strip El is first fastened to the sole plate and the heater `element placed thereon and clamped place. by theV pressure plate EQ2, theflatter beheld nrmly in place by screwsV its. An inf dependent .assembly is then made using plate il!!! as the basis or" theassembly. On the rear end of the plate thereis assembled `the shaft H5 .on which the bearing Vita-nd earn it havealready been asse1nbledthe bearing H5 Abeing screwed into the Iplate 93. VThe heel plate IZ is then iastened in place. The lever .arm l2? is then assembled to the plate by means of pin` 29 and` the contact springs i393 and I3l, terminal connections nel and it and .binding posts l and i154 are then all assembled on plate itil. It will Ybe ,observed that the maior portion of the thermostatio control, binding posts, switch parts,

. etc., are all on one plate which may be made un independently. The plate it isthen assembled in place in the groove .between Ywalls {c5- H35 of the pressure plate. and is held in place by means ofiourY screws H6 and lll, spring l'lE being iastened on screws lli. The shell i-l, plate 22 and handle [i8 are then assembled on the iron, the wiring connections being .made as previously indicated. The iron isthen connected to a source of electric power for` initial (or factory) adjustment and heating begins, Where the sole plate is of arnaterial having a greater heat coefficient of expansion than the thermostatic strip asseinbly, vthe heating of 'the sole plate above .ambient temperature causes the loop 92 to be retracted downwardly,thusallowing .the Contact spring I3! also to move downwardly, due to its resiliency. Theeontact .spring itt is sprung Yso as tobear against the insulating .tip 52e of lever ann taz, thelever arm in turn being tensioned byspring i'ltowards rotation in a counter-clockwise directiom-asillustrate inthe drawings. However, the movement of the lever 22 is liimted by the cam il? and thus the vupper spring contact ist! has, in effect, a predetermined position as determined by the cam il?. After the iron has heated sufficiently, the loop 92 permits the contact spring ll to move downwardly until the circuit is broken between its Contact and the contact on spring |30, and this action then continues intermittently heating the iron.

For factory adjustment the cam is turned by' means of knob |80 until it is at the high tel lperature end of thefligh heat range with pin I'IEa against tip iSZa. rlhe sole plate temperature may actually be too high or too low. If is too low, the knob i8@ and washer lill are removed, screw |53 loosened and bearing plate lili turned clockwise so as to lower the whole cam and hence push the end |29 of lever i downwardly, i. e. in the same direction it would moved if the cam is turned counter-clockwise toward the high temperature end of the scale. Adjustment is continued until the actual temperature of operation of the sole plate corresponds to the temperature selected for the "ll-ligh temperature end of the scale. Usually this high temperature is about 4Go F., but it may be set lower or higher as desired Figure e illustrates the position. or" cam il?? and the remaining parts in the Low heat condition. As shown in Figure 9, the low heat range of the cam has the greatest axial dimension eX- cept for the Oil position which will be described hereinaiter. By rotating the cam to the Low heat position the lever arm. |22 is moved upwardly at the left end 25, against the action of spring I lio, to a positio-n such that it permits the upper spring contact I3@ to assume the position shown in Figure 4. As the iron heats the loop S2 of the thermostatic strip assembly 3i is drawn downwardly and Contact strip I3i which rests against the insulating button 8E on the loop 92 is tensicned so that it follows the button downwardly as the loop is drawn down. As the iron heats the loop iinally permits the spring l! to move under its own resiliency and break contact with strip |39, thereby interrupting a circuit through the heating element of the iron. As the sole plate cools it contracts and loop S2 increases in elevation, thus raising contact i3l until a circuit is again established with contact strip 30 whereupon heating is resumed. This cycle of operation continues indefinitely as long as the iron. is in use.

When it is desired completely to interrupt the circuit through the heating element of the iron the knob IBS on the cam shaft lio is turned counter-clockwise until the pin i'lE-a engages the stop |82?) in which condition the cam surface |130 or" the cam |12 is brought into engagement with the lever |22, thus causing the lever 22 to be rotated a maximum amount in the clockwise direction, as shown in Figure 5. This permits contact to raise under its own resiliency te the condition shown in Figure 5. The contact I 30 is elevated so much that even when the sole plate has cooled to ambient temperature, the loop 92 is not elevated suiciently to bring the contact strip |3| into circuit-closing condition with contact strip |30. The axial dimension of the cam |13 at the Ofi position |730 is such that the circuit will not be completed until the temperature of the sole plate is reduced to or l0 degrees below zero Fahrenheit, and thus under any ordinary temperature conditions, the contacts 23o and I3| are maintained in open condition.

By rotating the knob |60 is the clockwise direction until the rod I 75a on shaft |15 abuts against the stop |82a, the high heat position of the cam (the portion that has the shortest axial dimension) is brought into line with the point |29 on the lever |22. When this adjustment to High temperature is made while the sole plate is cold,

10 the parts of the iron will assume the condition shown in Figure 2. When the iron is cold, the loop 92 on the thermostatic strip 8| is at its maximum elevation and it exerts a lifting force against contact spring |3| which transfers the force through its contact and the contact on strip i3d to the insulator button ld on the end 25 of the lever arm |22, and as a result the lever arm |22 is lifted against the action of spring lii. The opposite end i2t` and the lever 22 is moved away from the High heat portion ci the cam ile. if it is assumed that after such adjustment is made electric power is now supplied to lines "il and l2, the electric heating element is energized through the contacts |30 and il. The sole plate heats until the loop 92 is drawn downwardly. As the loop 92 is drawn downwardly, the lifting force against contact spring iol (which as previously explained was transferred through contact spring |3| to the lever i222) is gradually decreased and due to the tension of spring il@ the lever 22 and contacts |39 and |35 follow the movement of loop S2 downwardly as the iron heats, until the tip 3:? oi the lever nally engages the High heat portion of the earn |13, as shown in Figure 3, whereupon further downward movement of the lever 32 is rendered impossible. As the sole plate then heats, the contact i3! is permitted to move further downwardly, away from contact As the sole plate then cools, the loop 2 again rises and lifts contact spring |3I into circuit-closing condition with contact spring |30, whereupon the sole plate heats and the operation is continued indefinitely while the iron is thus in service. The make and break of contacts i at any temperature setting of cam |12 is not suiiicient to force lever |22 away from the cam, as the temperature over-run is negligiole. The mechanism is very sensitive and will maintain any set temperature within 10 F. Should the power supply to lines 1| and I2 be interrupted while the adjustment knob is in the High heat condition, the lifting force produced by the thermostatic strip I8| and loop 22 will not cause any permanent deformation of contacts 3| and |20, since, as previously eX- plained, once the contacts are brought into engagement, they serve to lift the lever |22 against the action of spring |79 and to cause the opposite tip of the lever 92 to move away from the high heat portion of the cam surface |13. In this way damage of the thermostatic control mechanism is obviated and uniform actual operation temperatures, corresponding to the established scale markings on knob |80, are maintained throughout the life of the apparatus.

If desired, the therniostatic strip element |8| may be made of a metal having a greater coeflicient of expansion than the sole plate, in which case the loop S2 is elevated as the sole plate and thermostatic strip are simultaneously heated. Where such construction is desired, the loop S2 is caused to actuate the contact spring |35 while the lever |22 is caused to actuate the contact spring 43|. However, it is more desirable from the standpoint of weight and convenience of manufacture to utilize aluminum or aluminum alloy for the sole plate I0 and utilize a material such as iron or invar, having a smaller heat coeiicient of expansion, for the thermostatic strip element 8|.

As many apparently widely diierent embodiments of this invention may be made without departing from the spirit and scope thereof, it

to ile-understood that weide not'flimitourselves to the specific embodiments hei-ein except as defined bythe appended claims.

Whatwe claim is:

l. In an electrical device having-ia plate and an electric heating element therefor, a oontrolfior said heating element comprising a composite strip of metal composed of two relatively stiff pieces aligned end-toend with a spacerbetween them and having their outer ends fastened tcsaid plate, saidnpiecesbeing joined together aci-'oss said space with an upwardly exed loop of ythinner material and a'pair of electric contacts connected in circuitrwith said electric heating element, said contacts being operable by change in elevation of said.- loop to open and close the circuit to .saidy heater responsive to variations in temperature ofV the plateAv and: composite strip assembly-` Y 2. In an electricalfdevice having a plate and an electric heating element-therefor, a switch connected in circuit-with theelectric heating element comprisingy thermostatic means for opening fand closing said switch including a strip oif'imetaisrecessed"intogroove in the upper surface. ofethe;ffple.te,..sairif strip being entirelf,T within saidzgroovev exceptzxthat 4itis flexed. up wardlyuat `one place. onlyiforoperating the switch but; otherwise held. in place-'inthe groove, said groove beingr recessedaateach: end` and theVv strip shapedgat, eacheoffiilrs endsiitolt said recesses fzon restraining:-V endwise movement i of` the ends oi the.: strip; and#l means for holding the ,strip in tbefgrooite;

3;., In an;electrical:devicefhzn/ing4 a plate and anxelectricali heaterfthereion: a control for said heaterA comprising-f aast-rip; of: metal having a dii'u nt heat coenicientf--ol expansion; than-said attached,abita-fondatothe-mate, said strip separate.' central; upwardly bowed. flexible nomen intersosedibetwen two flat red portions',2 butgo erwise in contact-g withytner plate, saidistrip-bein heldinaxial alignmenton said plata afheaterfSueerirnnoaedfupoo tho-plate and apressure plate vmountedlQn-f thee-heater vandz attachsd; to; @opiate/"ion holding .the assembly to gather,` said, heater element' and-pressureI plate being.,*centr-.allyY .apeltuiedto receive said central upwardly bowed flexible portion ottima@` str-ip, a pair oiswitch contacts, mountedfon said. pressure plate and positioned to-beactuatedg byV said up ward flexiblybowed strip portion for,l opening and ..c1osing 1theswitch,:Iesponsivey to, variations iniemseratulie ortho plata 4.# The combination comprising a,vv plate in which thereis ashallow groove in the, surface thereacross1a..composite--stripicompose-d .of piece ci a materiallhaving. a. different4 heatycoefcient ciV expansionthanthe plate and of aisize such. as tof ,tjl into said grooveirplaced inthe v,groove end to. endjwithaspace between .then/1,l said4 strips being joined together acrosssaid space by a flexible'. upvvardlybowedA pieceof material, means for fastenirpg,the extendingA ends vof the stripin the groovdga electrical heating element havingl anpaperture itsf center positioned onthe plater with the upwardly, .bowed biete4 of material @Xtendila therethrough, arressure relate,Y super.- imposed 'upon Athe -heatingelement and fastened to the plate for clan'lpingv the heating element therebetween, said pressurev plate7 beingl recessed toreceive said upwardly bowed-portion. of "the compositev strip,v a pair, of electric contacts connecteld'l` in" circuit with said; heating element mounted onthe lznessureI platevand mechanically 12 connectedto the upwardlyI bowed portion or the composite strip to be actuated thereby responsive to variation in temperature of the plate:

5.v The apparatus of claim'e'- further charac# terized in that said electrica-l contacts are posi-v tioned one above the other, one contact being actuatedbyvthe upwardly bowed portionV of the composite strip and the otherfcontact being man-l ually adjustable with reference to the -'rstvcone tact.

6. The apparatus of 'claim 4 further ycharacterized in that'the plate has a greater heatcoeiiicient of expansion than the composite strip, and the contacts are positioned one'over the other with the lower contact positioned so as tobe lifted Vby the upwardly bowed 'portion of thelex-- ible strip, the upper contact `being manually movable upVand-'down" for varying the temperal ture at which said contacts part.'

7. The apparatus of claim 4 further character`-A ized in that the'electric contacts are positioned one over"theV other, the lower Contact` being mechanically movable upwardly and downwardly responsiveto variations in i'exure of the upward@ ly bowed portion of the composite strip and the upper Contact: is. lnormally movable' upwardly and mechanical meansv is providedfor moving the upper contactV up 'and' down forv varying the tem:- peraturefof .the sole platetat which the contacts part.

8. Aswitch for anelectrioheater. sub-assembly having a .heatingplate andaani electric heater mounted. :on the heatingfplat'e', thef.combination of thermostatic means on the heating plate-Inovable;.vertically nresponseito variations in teme perature oitheheating plate; a pair .ofh 'contact strips havingcontacts thereonxconneoted. in cir'- cuit controlling f reiationf to the .electric heater,A

said contact strips beingV resilientlyl 'urgedtaway from each other, afrst'one 'ci said contacts'bei-ng mounted so as to berengageable byfthei thermostatic means. and; movable thereby towards` the secondfof said-contacts asthe,heatingrplateitemperature decreases, lever means mounted-"incoscillating relationV on thef-heatingplate and into en.-

gageinent with said second contact fonfmoving it towardsthe-.iirstf co-ntact,. spring means. sufficiently strong; to overcome the'resi'liency of` said contact-strips and: n'iovableA against thexlever means; for urging,l said*V second conta-ct'finto enev gagementzwith the-first contactwand manually adjustable stop means movableagainstsaid lever to move it in, a direct-ion` opposite tothe direc= tion-imposedbysaidspringcmeans;

9;, In an electric sadironjf sub-assembly having ascia-.plate andiany electr-ic heater' mountedtf'on the? sole plate, the; combinations; 'of thermostatic meansonn the sole 4platefrrioyable.fvertically'in response to-variations temperature ofv` the-'isole plate, aY pair ofcontactfstrps having contacts thereonconnected in. circuiti controlling relation to-theelectricgheatei., said contactstripsf being resiliently. urged.: away from eachother; aifirst one. of'. said` contacts ,beingfmountedfv so aszfto be engageable by thethermostatic means andfmovh ablevitherebyftowards *ther second of.I said contacts as the` sole, plate temperature-v decreases; lever means mounteddnoscillatingfrelationion the sole plate; and f into enggag,ement'.witiif` said7 second -contact for moving-it towardsitheirst. contacuspring meansr suiiioiently strong to; overcome; `the resiliency. of Asaid contact; strips. and:l movable;.against the lever 1 means for:- 1 urging said second contact intof-eng,agement.with. the-first-contactiandemane ually adjustablestopimeans movableagainstsaid lever to move it in a direction opposite to the direction imposed by said spring means, said lever being free to move away from said stop when the second contact is moved by the iirst contact when the latter moves responsive to the thermostatic means.

10. In an electrically heated device having a plate and an electrical heater therefor, a control for said heater comprising thermostatic means on the plate movable vertically in response to variations in temperature of the plate, a pair of contact strips having contacts thereon connected in circuit controlling relation to the electric heater, said contact strips being resiliently urged away from each other, a rst one oi said contacts being mounted so as to be engageable by the thermostatic means and movable thereby towards the second of said contacts as the plate temperature decreases, lever means mounted in oscillating relation on plate and into engagement with said second contact for moving it towards the 'first contact, spring means sufficiently strong to overcome the resiliency or said contact strips and movable against the lever means for urging said second contact into engagement with the nrst contact and manually movable cam means mounted so as to engage the vlever for moving it to varying positions against the action of said spring means.

l1. In an electrically heated device having a plate and an electrical heater therefor, a control for said heater comprising thermossatic means on the plate movable vertically in response to variations in temperature of the plate, a pair of vcontact strips having contacts thereon connected in circuit controlling relation to the electric heater, said contact strips being resiliently urged away from each other, a nrst one of said contacts being mounted so as to be engageable by the thermostatic means and movable thereby towards the second of said contacts as the plate temperature decreases, lever means mounted in oscillating relation on the plate and into engageW ment with said second contact for moving it towards the first contact, and manual means for oscillating said lever for moving the second con1 tact through a limited range oi positions in which it is engageabie by said iirst contact when the latter is moved responsive to said thermo static means and to an extreme position wherein the second contact is beyond the range or movement of said first contact,

12. In an electrically heated device having a plate and an electrical heater therefor, a control for said heater comprising thermostatic means on the plate movable vertically in response to variations in temperature of the plate, a pair of contact strips having contacts thereon connected in circuit controlling relation to the electric heater, said contact strips being resiliently urged away from each other, a irst one or said contacts being mounted so as to be engageable by the thermostatic means and movable thereby towards the second of said contacts as the plate temperature decreases, lever means mounted in oscillating relation on the plate and into engagement with said second contact for moving it towards the first contact, and manual means including a hanged disk rotatably mounted and including a cam on the flange thereof for moving said lever thro-ugh a range of positions thereby to vary the position of the second contact.

13. In an electrical device having a plate and an electrical heater therefor, a control for said heater comprising thermostatic means on the plate movable vertically in response to variations in temperature of the plate, a pair of contact strips having contacts thereon connected in circuit controlling relation to the electric heater, said contact strips being resiliently urged away from each other, a first one of said contacts being mounted so as to be engageable by the thermostatic means and movable thereby towards the second of said contacts as the plate temperature decreases, lever means mounted in oscillating relation on the plate and into engagement with said second contact for moving it towards the first contact, and manual means including a flanged disk rotatably mounted and including a cam on the ilange thereof for moving said lever through a range of positions thereby to vary the position of the second contact, the mounting for said hanged disk being mounted for moving the disk axially, and stop means for limit ing the rotation of said hanged disk.

14. In an electric sadiron sub-assembly having a sole plate and an electric heater mounted on the sole plate, the combination of thermostatic means on the sole plate movable upwardly when the sole plate is cooled and downwardly when increases, a lever pivotally mounted on the sole plate having one portion thereof positioned so as to engage and move the upper Contact downwardly, spring means for moving the lever in a direction to cause the upper contact to move towards the lower contact, said spring means being of suiiicient strength to overcome the resiliency of the upper contact spring and to cause its contact to close against the lower contact, and a stop positioned with reference to said lever to stop movement of said lever under the inuence 0f said spring means.

l5. In an electric sadiron subassembiy having a sole plate and an eiectric heater mounted on the sole plate, the combination of thermostatic means on the sole plate movable upwardly when the sole plate is cooled and downwardly when the sole plate is heated, a pair of cooperating electrical contacts mounted on spring contact strips mounted on the sole plate one above the other, said spring strips being iiexed so as normally to urge the contacts away from each other, the lower contact being mounted in respect to the thermostatic means so as to be raised thereby when the sole plate temperature decreases and to be lowered when the sole plate temperature increases, a lever pivotally mounted on the sole plate having one portion thereof positioned so as to engage and move the upper contact downwardly, spring means for moving the lever in a direction to cause the upper Contact to move towards the lower contact, said spring means being of sucient strength to overcome the resiliency of the upper Contact spring and to cause its Contact to close against the lower contact, and a stop positioned with reference to said lever to stop movement of said lever under the influence of said spring means, the position of said stop being manually variable so as consequently to vary the position of said lever and upper contact.

i6. In an electric sadiron sub-assembly having

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