US1388111A - Electric stove - Google Patents

Description

A C. HARRINGTON.

ELECTRiC STOVE.

APPLICATioN HLED MAY'za. 1920.

1,388 ,1 l l v Patented A110'. l16, 1921.

A TTOH/VEYS adjusting means in connection wit PATENT OFFICE.

.ALLAN C. HABRING'TON, 0F CHICAGO, ILLINOIS.

ELECTRIC STO'VE.

Specification of Letters Patent. Patented Allg. 16, 1921.

Application illed Hay 28, 1920. 'Serial No. 384,884. f

following is a full, clear, and exact descrip-- tion. This invention relates to electric stoves, and has particular reference to one in Whlch thermostatic control of the generated heat is provided'.

An objectof the invention is to provide asimple, compact electric stove in which the generated heat is under a much finer degree of control thanis usually the case.

Another object is -to provide 'a theremostatic device in which the response of the thermostatic element to the generated heat is uniform and sensitive to a very high deree.

Still another object is to provide a means whereby the .heater circuit may be opened and closed at predetermined temperatures by the use of a simple and readil operable li the thermostat.

The invention in general comprises a receptacle having double walls between -which there is a vacuum and which contains an electrical heating element. Also located Within the. receptacle is a therm'ostatic ydel vice in the form of a coiled spring o f' heatresponsive material. `rI his spring is connected to suitable linkage, whereby a leverI arm connected thereto on the exterior of `the receptacle is moved either to indicate the v temperature Within .the receptacle or to move al switch or to perform some other function. In order to insure that the expansion and contraction of this coil spring may be very uniform and result in an increased sensitivity of the device, Iit is provided that at 'frequent intervals throughout its length the coiled spring is confined on both sides by guiding elements, so that when a tendency exists to expand under heat, the general coni figuration ofthe spring when coiled i's maintained and the expansion takesv place substantially entirely along the length .of the spring. In this way an increased movement of the spring is obtained which is effective to move the indicator or other device on the exterior o f .the receptacle. f

This thermostatic element is connected by suitable'means to a rotatable element on the exterior of the receptacle. Adjacent this rotatable element is an electric circuitcloser. The circuit closer is connected to thevrotatable element b means of an adjustable link, the position o which may be varied at will, to determine the amount of movement of the rotatable element required before its movement results in either the opening or closing of the circuit closer.

The inventiony is illustrated in the drawing, of which- Figure l is a longitudinal section of the stove taken on the line l-l of Fig. 2;

Fig. 2 is a plan view of the stove; Fig. 3 is an enlarged plan view of the top of the circuit-controlling means locatedv on the top of the stove;

Fig. 4 isa vertical section taken on the line 4-4 of Fig. 3;

Fig. 5 is a horizontal line 5--5 of Fig. .4; and

Fig. 6 is a detail view of the circuit-closer terminals. k As'illustrated in the drawings, the invention comprises a reoeptaclehaving innerand outer walls 1 and 2 and a tight-fitting cover, which also has inner and outer walls 3 and 4. These walls may be made of any suitable material, such as glass, porcelain or metal, and may be joined in an air-tight manner by any method known in thearts. Between section taken on the v placed therein to more effectively prevent the radiation and conduction of heat from the interior of the receptacle to the exterior.

Positioned within the receptacle, preferably on the bottom, is a heater element, represented by the numeral 5. This element 5 is only diagramm-atically represented, since it may be of any w'ell-knovvn'andY suitable form. A pipe 6 extends from this element 5 to the exterior of the receptacle and passes through the `space between the walls to the outside and provides a passage for the circuit wires 7 and 8. These wires extend to a circuit closer to be hereinafter mentioned.

The cover of the receptacle is connected thereto in any suitable manner and is provided on its inner surface with a casing 9,

which may be riveted or screwed thereto.

- which is of any Suitable man which is particularly responsive to changes in temperature. This spring is wound in a flat spiral, the inner end of the spring being connected to a shaft 11 and the outer end being connected by a pin to aplate 12. The plate 12 is loosely mounted on the shaft 11. This shaft 11 is, at its lower end, fixed in the casing 9 and extends upwardly from the cas` ing 9 in a tube 13, which tube is sealed between the inner and outer walls of the cover so as to make it air tight. The upper end of the shaft 11 is fastened to a plate 14 on the top of the cover. Along part of its periphery the plate 12 is provided with teeth 15 which are adapted to mesh with a pinion 16 mounted on the lower end of shaft 17 and which extends upward from the casing 9 in atube 18, similar to the tube 13, and at its upper end is connected to a plate 19. The plate 19 is provided with a slot in the form of a sector 20. A link 21 is loosely pivoted to the upper end of shaft 17 and, intermediate its length, is provided with an adjustable nut 22, a portion of which rides in the slot 20. This nut and slot arrange ment provides means whereby lthe linl 21 may be adjusted in any position with respect to the plate 19. The outer end of the link 2l is connected by a spring 22 with arm 23 of a circuit closer. This arm carries a contact plate 24 on its outer end, which is adapted to dispose itself between terminal springs 25 and 26 which are adapted to be connected to the circuit wires 7 and 8.

It will be readily seen that by varying the position of the link 21 in the slot 20 more or less movement will be required of the plate 19 under the influence of the thermostatic element in order to either open or close the switch, as the case may be,so that a rather wide degree of adjustability is provided by this simple means.

As more clearly shown in Figs. 4 and 5, a plurality of to one face o the casing 9. spaced apart at short intervals in lines which preferably, and as show n, extend at right angles to each other. The spring 10 is threaded in a flat spiral form between these pins, which, therefore, confine the lateral movement of the spring at frequent intervals throughout its length. The spring, therefore, in expanding is prevented from moving laterally to any substantial degree and, therefore, tends to move entirelyT 1n a longitudinal direction, thereby resulting in the most eflicient indication for any given change of temperature.

By the mechanism and the arrangement thereof above described it will be readily seen that have provided asimple, compact stove, adapted to be heated electrically, in which heat-controlled device is located hese are and in ins 27 are securely fastenedl a simple and' easily adjustableceptacle, a circuit closing arm, an element cooperating with said thermostatic device and movable in response to the movement thereof, said element cooperating with said circuit closing arm, connections between said element and said'circuit closing arm, and means for adjusting the relation of said connection with respect to the circuit closing arm and said element.

2. An electric stove comprising a receptacle, a heating element within vthe receptacle, a thermostatic device within the receptacle, a circuit closing arm, a rotatable member operatively connected to said thermostatic device and coperating with said circuit closing arm, an arm onsaid rotatable member, said arm connected to said circuit closing arm, and means for adjusting the relation of said arm with respect to the circuit closing arm and the rotatable member.

3. An electric stove comprising a receptac1e,.a heater element within said receptacle, a thermostatic device within said receptacle, a rotatable plate o eratively connected to said thermostatic evice and having a circular slot therein, a circuit closer, an arm connected to said rotatable plate and to said circuit closer, and means connected to said arm and o eratively associated with the slot to adjust tlie arm with respect to the rotatable plate and determine the character of the opening and closing of the circuit closer.

4. A thermostatic device comprising a coiled spring one end of which 1s free to expand, means positioned at intervals throughout the length of the spring to conne its movement substantially to a direction coincident with its length.

5. A thermostatic, device comprising a coiled 'spring one end of which is free to expand, a plurality of devices positioned along the length of the spring to confine the spring to its originalconguration when cold so that when expanding under the inuence of heat this original configuration is maintained and the expansion 1s substantially entirely longitudinal.

GpA thermostatic device comprising a coiled spring one end of which 1s fre'e to expand, stationary devices positioned at incomprising a recep-f tervals throughout the length of the spring' to prevent lateral movement of the spring inexpanding. w

7. A thermostatc device comprising 'n coiled spring one endV of which 1s lfree to expand, a plurality of pins positioned on both sides of said spring at throughout its length, said pins adapted to confine the movementjof the springft a 1.0 direction parallel with itself.

8. A thermostatic device comprising a intervals .coiled spring one end of Ywhich is free` to expand, a'plural'ityof devices positioned alongthe length `ot said spring to conine it to a longitudinal movement, a movable plate fastened to the free a shaft operatively connected on the said movable plate, an arm on lthe outer end l of said shaft, and an indicating device con-` nected to and operated by saidarm.y

ALLAN c.- H'ARRINGTON.

15y end of the frame,v

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