US2257131A - Temperature-controlling flatiron stand - Google Patents

Description

Sept. 30, 1941. sAHLl 2,257,131

TEMPERATURE-CONTROLLING FLA'IIRON STAND Filed April 5, 1939 T1 II .1

INVENTOR losse 7* 54 H4 B {M fl, ATTORNEY Patented Sept. 30, 1941 UNITED STATES PATENT OFFICE Robert Sahli, Basel, Switzerland Application April 5, 1939, Serial No. 266,110 In Switzerland February 24, 1939 2 Claims.

This invention relates to a flatiron stand with automatic disconnection of the heating current when the working temperature of the fiatiron is exceeded and automatic reconnection with the aid of a bimetallic strip.

Flatiron stands of this type are known, in particular also those in which the massive metal plate forming the shelf surface of the grid is connected with a bimetallic strip, the deflection of which upon heating controls a mercury switch positively.

The previously known stands of the said type exhibit many disadvantages, however, which become of importance especially in the frequently occurring case of ironing heavy laundry, for example starched laundry, or in the case where evaporation takes place on ironing damp clothes etc., whereupon large quantities of heat are rapidly withdrawn from the flatiron. In such cases the flatiron, after it has been switched 01f, must very rapidly be switched on again since otherwise it would cool down too far. The most favourable time for reconnection amounts according to experience to about 30-50 secs. Electrical stands which require a connection time of 2-3 mins. or more are therefore not utilisable industrially. Such short connection times however cannot be obtained with the previously known stands with mercury switches because of the manner of their construction.

It is an object of the invention to provide a fiatiron stand with automatic disconnection of the heating current when the Working temperature of the flatiron is exceeded and automatic reconnection with the aid of a bimetallic strip,

which is characterised in that the massive plate forming the stand has a slot which is covered with a thin sheet metal strip of low heat capacity, to which one end of a bimetallic strip is secured, whilst the free end thereof acts upon a lever system which is connected with a mercury switch, the construction and arrangement of the lever system being so chosen that the deflection of the bimetallic strip is magnified and the mercury switch is only operated after a definite period of time after the beginning of the deflection of the end of the bimetallic strip, whilst means are further provided for returning the lever system together with the mercury switch into the position of rest.

An embodiment of the invention is illustrated by way of example in the drawing, in which- Fig. 1 shows a partially sectioned side elevation of a flatiron stand according to the invention, and

Fig. 2 shows a partially sectioned end elevation.

the thin and narrow sheet metal strip I pro- .vided with holes la and covering the slot 2a of the carrier plate 2, whilst the free end lc of the bimetallic strip is bent away from the sheet metal strip l. The bearing member 3 for the screwthreaded spindle 4 is arranged upon the wall 21) of the stand housing. The block 6 which carries the levers 7, la, the rod 9, the lever 8, the pivoted mercury switch H and the return means I0 is secured to the screw-nut 5. The double-armed lever 1, 1a is secured to the shaft lb. The singlearmed lever 8 is secured to the pivot shaft 82). The lever arm la is connected articulatedly through the rod 9 with the lever 8.

The spring l0 serves for returning the lever system and the pivoted mercury switch to the starting position. The screw-nut 5 together with the block 6 can be raised and lowered along the spindle 4 by means of the bevel gears l2 and I3, the shaft l4 and the crank 15 arranged outside the housing to move over a scale (not shown), graduated according to the degree of heat, whereby it is possible to increase or reduce the distance between the free end Ic of the bimetallic strip and the lever arm I and hence to increase or reduce the lost motion.

The manner of operation of the apparatus is as follows:

The flat iron traversed by current is placed upon the sheet metal strip I whereby the latter is heated and transmits heat to the bimetallic strip la, as a consequence of which the free end 10 of the bimetallic strip curves down towards the lever arm 7. Because of the distance present between the end lc of the bimetallic strip and the lever arm 7, it will take a certain time, depending upon this distance, before the end is will press upon the lever arm 1 (lost motion). By operation of the crank i5 the block 6 can be raised or lowered, so that when the fiat iron reaches a predetermined temperature the end is of the bimetallic strip begins to press upon the lever arm I, whereupon the mercury switch is operated after a certain time and the heating current is switched off. When the cooling of the fiat iron which now begins has proceeded so far that the pressure of the end lc of the bimetallic strip upon the lever l ceases, the current is then automatically switched on again and the iron begins to be heated again. This operation is repeated regularly.

Of course the levers of the lever system may be arranged with respect to one another in another manner than that described above. Thus, for ex- I'he bimetallic strip lb is riveted at one end to 55, ample, the lost motion may be arranged to take place at other parts of the lever system instead of between the end of the bimetallic strip and the first lever of the lever system, or instead of connecting the two levers of the lever system articulatedly with one another, an articulated connection may be arranged at another part, for example between the end of the bimetallic strip and the first lever.

The block 3 may also of course be constructed in another manner, and instead of being mounted on the side wall of the stand housing may be mounted upon another part of the housing, for example on the floor or the cover thereof.

What I claim is:

l. The combination with a stand for an electric iron, of means mounted therewith through which current is supplied to the iron, and heat controlled means mounted therewith for cutting on? current to the iron upon a rise of tempera:

ture of the heat controlled means when the iran prising in combination a perforated metal strip of low heat capacity and directly contacting the iron when on the stand, a bimetallic thermostat element directly connected at one end with said metal strip, a lever system adapted to be engaged and actuated by the other end of said thermostat element upon deflection thereof under the influence of heat and to augment the movements of said other end, an electric switch meansconnected with said lever system and adapted to cut off the electric current when said lever system is actuated by the deflected element, and return means connected with said switch means for re turning said switch into current switching on position when said lever system is not actuated, said thermostat element, said lever system, and said switch means being so constructed as to move in the same plane when actuated by the heat absorbed by said metal strip.

2. The combination with a stand for an electric iron, of means mounted therewith through which current is supplied to the iron, and heat controlled means mounted therewith for cutting off current to the iron upon a rise of temperature of the heat controlled means when the iron is on the stand, and for immediately switching on the current to the iron upon a fall of temperature of the heat controlled-means when the iron is off the stand, said heat controlled means comprising, in combination, a metal strip of low heat capacity and directly contacting the iron when on the stand, a bimetallic thermostat element directly connected at one end with said metal strip, a lever system adapted to be engaged and actuated by the other end of said thermostat element upon deflection thereof under the influence of heat and to augment the movements of said other end, an electric switch means connected with said lever system and adapted to cut oil the electric current when said lever system is actuated by the deflected element, return means connected with said switch means for returning said switch into curent switching on position when said lever system is not actuated said thermostat elernent, said lever system, andsaid switch means being soconstructed as to move inthe same plane when actuated by theheat absorbed by said metal strip, a common mounting means for said lever system and said switch, and an adjustable support and pos ition changing means for said mounting means for simultaneously, adjustably changing the position of said lever system and said switchwith respect to said thermostat 'element, said support and position changing means comprising a threaded spindle, bevel gears connected therewith, and a revolvable adjusting shaft connected with said bevelgears and extending outside of said stand, whereby upon manipulation of said shaft fine adjustment of the position of said mounting means is efie cted.

ROBERT SA'HLI.

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