US2431186A

US2431186A - Electric iron

Info

Publication number: US2431186A
Application number: US501203A
Authority: US
Inventors: Paul J Mccullough
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-09-04
Filing date: 1943-09-04
Publication date: 1947-11-18
Anticipated expiration: 1964-11-18

Description

Patented Nov. 18, 1947 ELECTRIC IRON Paul J. McCullough, St. Louis, Mo., assignor to Joseph Pavelka, St. Louis, Mo.

Application September 4, 1943, Serial No. 501,203

6 Claims.

The invention relates to electrically heated smoothing irons such as are generally used for domestic ironing, for clothes, etc., and the invention consists in novel means for controlling the temperature of the iron.

It is a common practice to provide such an iron with a thermostat which opens the heater circuit when the temperature rises to a predetermined degree above which it is likely to scorch the material being ironed and the thermostat closes the heater circuit when the temperature drops to a predetermined degree below which the iron will be ineffective. Usually the iron is provided with an adjustable control whereby the range of the thermostat may be varied by the user to lower the range of temperatures when the iron is to be used on thin material or to raise the range of temperatures when the iron is to be used on heavier materials.

If the iron is set for use on heavier materials and the ironing operation is interrupted for a substantial period and the iron placed on its heel, as is customary, the thermostat will continue to function as described above but obviously the iron would be maintained at an ironing temperature, consuming current and maintaining the heating element at a temperature continuously higher than it would be subjected to if the iron were set for ironing lighter material or if the iron were in use and were applied to relatively cool material. Some irons are provided with a device which opens the circuit when the iron is stood on end in an inoperative position and closes the circuit when the iron is again placed in operative position. If the interruption has been long enough, the iron will have cooled so far below ironing temperature that it is necessary to wait for the iron to heat up again. Hence this arrangement is not altogether satisfactory although it reduces current consumption and destructive heating of the element.

Some irons have a thermostat automatically opening and closing the heater circuit as the thermostat temperature rises and falls below a given temperature, but this temperature does not change automatically when the iron is shifted from an ironing position to a non-ironing position.

The mainobject of the present invention is to provide automatic control of the element heating circuit within one range of temperatures when the iron is in use and within a lower range of temperatures when the iron is not in use.

This and other detailed objects of the invention are attained by the structure illustrated in the accompanying drawings in which- Figure 1 is a top view of an iron sole plate showing a portion of the heating element and a cover plate thereover and control mechanism, the top of the iron being removed.

Figure 2 is a vertical longitudinal section through the iron showing the control mechanism in the position assembled when the iron is in use.

Figure 3 is a similar section showing the control mechanism when the iron is not in use and is stood upon its heel.

Figure 4 is a detailed perspective showing a portion of the control mechanism.

The sole plate I mounts the heating element in the form of a resistance grid 2 having terminal Wires 2a and 21) connected to posts 9 and III. A top plate 3 is mounted on sole plate I and covers the heating element. An upwardly convexed cover 4 is applied to the sole plate and provides a space above plates I and 3 for the automatic switch control for the heating element. A handle 5 rises from the cover and is provided with a slide 6 by which the temperature of the iron is manually adjusted by the user. The central portion of plate 3 is cut away and the sole plate is recessed downwardly below the area of the cut away portion to permit positioning of some of the control mechanism nearer to the bottom of the sole plate and thereby render it better subject to the critical temperature of the ironing surface of the sole plate.

The heating current is supplied through a cord 1, one wire 8 of which is connected to post 9, the other wire II of the cord being connected to a post I2 which may be connected to post I0 by a switch mechanism which includes a spring blade I3 anchored at I4 to a member electrically connected to post I2. The switch also includes a plate I5 hinged at I6, and subject to downward thrust from a spring IBa, so as to be tilted vertically by a roller II engaging the forward end of the plate and mounted on a pivot arm I8 and adapted to be engaged by the lower end of an arcuate extension 20 of slide 6. By moving slide 6 in the direction of arrow A, roller I1 is thrust inwardly, raising the forward end of plate I6 and a switch blade l9 thereon, bringing the switch contacts 2I on blades I3 and I9 closer together. This construction constitutes an improvement upon that disclosed in Patent No. 2,124,984, issued to the present applicant July 26, 1938.

A bimetal thermostat strip 22 is anchored at one end 23 to the sole plate and is free to distort at its opposite end 24in accordance with the temperature to which it is subjected. A sleeve 25 of porcelain or other insulation forms a strut between the outer end of the thermostat and the outer end of switch spring blade I3 and as the thermostat heats and distorts, it will open the circuit of which wire Illa and post I0 form a part, thus cutting out the resistance grid of the heating element until the thermostat cools and moves towards its normal position far enough to bring contacts 2| together again. Hinge plate I5 and switch blade I9 are secured together at the right hand end of the latter and are spaced apart at the left hand end of blade IS, The spacing is variable and is controlled by a gravity-actuated device (see Figure 4) comprising a rod 26 journalled at 21 on plate I5 and having an arm 28 underlying blade l9 and an arm 29 mounting .a weight 38. When the iron is in the horizontal or functioning position shown in Figure 2, weight 30 will turn rod 26 to elevate blade :19 to anormal position corelated to the thermostat and to the normal position of blade 13 so that "the contacts 2| will remain engaged throughout a range of temperature suniciently high for ironing purposes.

When the iron is upended and stood upon its heel, as indicated in Figure 3, weight 30 will rotate rod 26 and its arm 23 to relieve blade H) of thrust from the arm and permit the blade to move back towards the hinged blade l5 in Which position it will be necessary for the thermostat to cool and distort to a greater degree before bringing contacts 2! into engagement than would be the case if the iron were horizontal.

It will be understood that when the iron cord is plugged into a suitable outlet the circuit for the resistance heating element is closed (although, if desired, the cord may be provided with a manual switch) and this circuit remains closed except for control of the iron effected by slide 6 or by the thermostat or by the weight 30. When the iron is upright, the spacing of the switch blades will be such that the thermostat will close and open the circuit at a different rangeof temperatures than when the iron is disposed horizontally, in which latter-mentioned position the weight will be effective and the upper blade l3 will approach lower blade l9 and hence the contacts will be brought together sooner as the thermostat cools than they would when the iron is upright. The difference in temperature range in the two positions of the iron may approximate 75.

It will be understood that the details of the switch structure and the thermostatic device and the gravity device and the connections between these devices and the switch elements may be varied substantially without departing from the spirit of the invention, and the exclusive use of those modifications coming within the scope of the claims is contemplated.

What is claimed is:

1. In an electric iron adapted to be placed in a functioning position or in a nonfunctioning position, a heating element, a switch controlling the circuit for said element and including contacts movable towards and away from each other, gravity-actuate means for moving one of said contacts relative to the other contact when the iron is shifted from one of said positions to the other of said positions, and thermostatic means operable on the latter-mentioned contact to move it relative to the gravity-moved contact in accordance with the temperature to which it is subjected, said switch closing at a predetermined temperature range when the iron is in afunctio-ning position, and closing at a temperature range lower than said predetermined temperature range when the iron is in a non-functioning position.

2. In an electric iron, a sole plate provided with a heating element, a thermostat associatedtherewith, a switch for controlling the circuit for said element and comprising adjacent spring blades with individual contacts, said thermostat, when heated, distorting one of said blades to move its contact away from the other contact, and a gravity deviceassociated with the other blade and distorting it to move its contact closer to the contact of the thermostatically-actuated blade when the iron is shifted from a relatively inclined idling position to a horizontal ironing position.

3. In an electric iron, a sole plate, a thermostat adjacent said sole plate and having a portionarranged to move away from said sole plate when heated, a switch blade operatively engaged by said thermostat portion, a cooperating switch blade-alongside said first-mentioned switch blade, a gravity-actuated device operatively connected to said second-mentioned switch blade and adapted'to movethe same towards said first-mentioned switch blade when the iron is horizontal and to release said second-mentioned switch "blade when the iron'is upended.

4. In an electric iron, a sole plate, a heating element, a two-part switch controlling the circuit for said element, a thermostat secured to the .sole plate and having an operable connection to one of said switch parts, the other of said switch parts having a pivotal mounting on the sole plate and being provided with gravity means for shifting its position relative to the first-mentioned switch part when the iron is moved from a substantially horizontal ironing position to a substantially vertical idling position, the temperature at whichsaid thermostat closes said switch being .in a.lower temperature range when said iron .is in a vertical idling position than when the iron is in a substantially horizontal ironing position.

.5. In an electric iron, a heating element, a switch controlling thecircuit for said element and comprising a plurality of movable parts, a thermostat for actuating one of said switch parts to open and close the switch at a predetermined temperature range when the. iron is in an ironing position, and means automatically shifting the position of the other switch part to cause said thermostat to open and close said switch at a temperature range lower than the pro-determined temperature range when the iron is shifted from an ironing position to a non-ironing position.

6. In an electric iron, a heating element, a

switch controlling the circuit for said element and comprising a plurality of movable parts, a thermostat .for actuating one of switch parts to open and close the switch at a. predetermined tempera.- ture range when the iron is in an ironing position, and means to move the other of said switch parts out of engagement with said thermostat actuated switch part to open the switch when the iron is .moved from an ironing to a non-ironing ,position, said thermostat actuating said firstmentioned switch part to open and close the switch at .a temperature range lower than said predetermined temperature range when saidiron isin non-ironing position.

PAUL J. McCULLOUGH.

REFERENCES CITED The iollowing references are .of record in .the file of :this patent:

UNITED STATES PATENTS Number Name Date 1,582,068 ,Morrissey Apr. 27, 1926 1,634,431 ,Myers July 5, 1927 1,742,558 Randolph .Jan. 7,, 1930 2,008,484 Belcher Jul 16, 1935 2,277,034 Bisley vMar. 24, 19.42