US1570687A - Thermal switch for electric irons - Google Patents

Description

jam, 26 @26 J. N. LEWIS THERMAL SWI TC H FOR ELECTRIC IRONS Filed April 29, 1922 ENC., fr @@QPURATON Bln h Application lled April 9,9, Serial t'o.

To aZZ whom t may concern:

Be it known that l, Jixruss N. Lewis, a. citizen of the United States of America, residing at Detroit, in the county of lfayne and State of Michigan, .have invented certain new and useful linprovements in 'lherinal Switches tor Electric iirons, of which the following is ka specication, reigerence being had therein to the accompanying drawings.

This invention relates an automatic control device for electric irons and tlie pri mary object oit my invention is to provide an electric iron which will eliminate lires incident to overheated irons being left on an ironing board or other combustible supports. lt is a well linown tact that a large percentage ot' tires occur by the operator or" an iron neglecting to turn oil the current after using 'the iron or when temporarily leaving the same on an ironing board or other supports Another object of my invention is to pron vide a diaphragm control device of general application, but especially designed :tor an electric iron, the device utilizing the expansive orce of a medium for flexing tlie diaphragm in one direction, and partial vacuum or the inherent retractive `force on the diaphragm for flexing it in an opposite direction. As an instance oi' such diaphragm actuating medium may be cited a liquid or low beat coeilicicnt and by its volumetric displacement cause lexure of the diaphragm.

A further object of this invention is to furnish an iron with a diaphragm control device that will automatically cut on and ofi an electric current to the iron and tlius prevent waste of current and obviate the necessity of the operator of the iron turning on and oil a switch each and every time the iron is to be rendered inoperative.

i still further object oi my invention is to rnish iron with a diaphragm control cvice that may be sot at will `for desired -niniinum and maximum temperatures in connection with the iron. For instance, the control. device may be regulated to shut ofi to the iron at a maximum temperature and turn on the current at a minimum temperature, thus permitting the operator 'to set the iron for dii'ierent lrinds Worin stillv further obiect of? my i 'to provide an iron witli a switcl leverage mechanism tor switch, the leverage mechanism permit g of the iron bein@- very sensitive to least fluctuation in temperature consequently the control or the iron may be regulated to a line degree as may be essential in connection with various kinds of work.

The above are a few of lthe ooccts tained by the simple and durable construction to be hereinafter described, and. reisrence will new be had `to the wherein Figure l a horizontal sectional view the iron;

Fig. 2 is a .longitudinal vertical sectional View of the saine, and

Fig. 3 is a cross sectional view talren on the line Tillmll'i of Fig. 2.

n the drawing the reference numeral l denotes an iron body having its upper :tace provided with a marginal wall 2 and on said base, within said wall, is an electric heating element 3, said element being of the ordinarg,T and well known t* pe including a resistance coil and suitable insulation.

@ver the electric heating element 3 is placed a shield made of insulation mate rial, for instance asbestos and this shield has depending side walls 5 resting on the iron body l at tbe outer sides of tbe marginal wall 2 so as to cooperate with said wall in electric heating element and thus coni'ine the heat in the lower portion of the iron body, preventing its dissemination in the upper portion ci the iron body, and consequentlvv a waste ot' the energy supplied to the elecric healing element.

Extending over the top ot tlie shield 4i 's a spider having longitudinal arms 6 and tr verse arms T, the arms 6 having the outer ends thereof connected by screws 8 o other fastening means to the marginal wall and the ends ot the arms 7 extend downwardly at the outer sides of the depending walls 5 ol' 'the shield el.

Centrally o the spider is a hold tending into an opening l() yin the shield Il, the holder 9 being directly above the electric heating element and susceptible to the heated air within the chamber containing' the bea* element. Suite-.bly attached. to holder l) is a hermetically sealed co or diaphrfim device. 1l susce p ilil plug 12 mounted in said holder, said plug permitting of the container being filled with mercury, oil or any liquid or material hav.

ing a low coethcient of heat expansion. The device 11 can be conveniently made-ot two circumferentially corrugated ldisks or d1aphragms having flanged edges secured together to form a chamber or hollow member, and with the lower wall of the member held by the holder 9 the upper wall or diaphragm of the member may be idexed by volumetric displacement or the medium within the member or container.

@n the forwardmost arm 6 of the spider is an upright bearing 13 and pivotally connected to said bearing is the forward end of a lever 14, said lever extending rearwardly over the top of the control device 11. Screwed in the lever 14, coaxially of the control device 11, is a Contact member having a head 1G adapted to be engaged by a pad 17 centrally of the control device 11. Mounted on the contact member 15 and bearing on the lever 14 is a fingerpiece 18 locked relative to the contact member 15 by a set screw 19. With the set lscrew 19 loose the finger piece 18 may be adjusted relative to the Contact member said Contact member may be adjusted in the lever 14. Suchad. justment, however, is limited by either the head 16 contacting with the lower face of the lever 14 or the finger piece 18 contacting with the upper face of said lever. As the contact member 15 is set in Fig. 2, it may be engaged by the pad 17 and the lever 14 ac.- tuated to operate a switch.

On the forward arm 6 of the spider and on the marginal wall 2 of the iron body 1 are posts 20 provided with detachable nuts 21 employed for positioning and holding a cover 22 on the iron body. rlhis cover has its rear wall 23 provided with a housing 24 and fixed in said housing is an insulator 25 provided with binding posts 26 and contact members 27. Slid ble in the insulator 25 is a pin or plunger 8 having a conical head 29 held normally in engagement with the contact members 27 byl the expansive force of a coiled spring 30 encircling thepluvnger 28 within the insulator. The upper end of the plunger has a transverse pin 31 engaged by the forked or bifurcated end 32 of the lever 14 so that said lever may raise the plunger 28 against the action of the spring 30 or permit the expansive `torce of said spring to lower the plunger 28.

The housing 24 supports the usual acks 33 adapted to receive a soc-ketor plug (not shown). One of the jacks 33 is connected by a conductor 34 to one of the binding posts 26 and the other jack is connected by a conductor 35 to the electric heating element hardest' 3, which in turn is connected by a conductor 36 to the binding post 26.

Suitably attached to the .cover 22 is a conventional form of handle 37 by which the iron may be manipulated.

It is through the medium ofthe adjustable Contact member 15 and the control device 11 that the iron may be set to turn on the electric current when theiron has cooled, for instance one hundred and twenty-five degrecs Fahrenheit and turn olf the electric current when the iron has heated to the ex*- tent or three hundred and fifty degrees Fahrenheit or any limits 'that may be selected by 'the user of the iron, but under no circumstances will operation of the iron be permissible at a heat that may cause a tire if the current is not shut off after using the iron. lilith a very sensitive control device and 'the advantage of leverage between said device and the switch it is possible to regulate the action ot' the iron to a tine degree and such degree may be set by the manufacturer so that the iron cannot be conveniently tampered with and its automatic safety feature destroyed.

It is thought that the operation and utility ofthe electric iron will be apparent without further description, and while in the drawing there is illustrated a preferred embodiment of my invention, it is to be understood that the structural elements are susceptible to such variations and modifications as fall within the scope of the appended claim.

ln an electrically heated iron having a cover under which is located an electric switch and a thermostatic control device adapted to control said switch and the heating of said iron ineans for supporting said thermostatic control device and mechanism by which said switch may be actuated by said device, said means comprising a fourarm spider under said cover on which is mounted said thermostatic control device, a bearing on one or' the arms of said spider at one side of said thermostatic device, a lever pivotally supported by said` bearing between said spider and said cover and extending in the direction of another arm of said sp1der and articulated with said switch, said thermostatic control device being at the juncture of said spider arms and having a portion thereof 'attached to said spider, and means carried by said lever opposite the attached ortion of said control device and extending through said cover adapted for adjustment to regulate the operation of said lever by said thermostatic control device.

In testimony whereof I alix my signature.

JAMES N. LEWIS.

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