US1898691A - Electric switch - Google Patents

Description

G. SCHAFER ELECTRIC SWITCH Feb. 21, 1933.

Filed Dec. 3, 1930 in veizzor Patented Feb. '21, 1933 V UNITED STATES PATENT orrlcr.

. us'rav sexism, or armour, cumin? 7 mc-rmc 'swrrcn Applicatlon fled December 3, 1980, lerlal Io;

The known automatic switches for electrically heated implements sufier from the drawback that their sensitiveness to temperature is too slight and that dimensions are too 5 large for many urposes of use. The present automatic switc is distinguished by its high sensitiveness-j it operates, for instance, at a difference of temperature of 3 C. Besides, it can be made so small that it can be inserted,

for instance, into the plug of an electric ticularly small and consists of a comparatively wide, short and rigid part and of a comparatively narrow, semi-circular tubular sprin which joins said first-mentioned part axia y and is at its free end connected with a switch lever formed by a turnably arranged leaf spring, the free end of which acts upon a contact or contacts and co-operates with two other, but smaller leaf s rings by which it is retained or checked in the one and the other of its two switchin positions (that in which the current is switc ed on and that in which it is switched 05) until it is released by reason of its increasing bending through, whereafter the chain 'ng-over takes place instantaneousy sa1 by the interme iary of a lever, as is all more as fuiltv described hereinafter. y

invention is illustrated diagrammatically and'by way of eXampleon the-accompan'ying drawing on which Figure 1 is a plan of a switch designed according to this invention, and Figure 2 is a front-view thereof.

' The construction is as follows:

In the augularly bent part b of the base plate a is supported the comparativel lar 'ri 'd container d from which exteng foifiii 45 axially the tublar spring d which, in contradistinction tothe known tubular springs used in connection with electrically heatable implements, is semi-circularly shaped. Both partsdand d are. filled with a suitable liquid substance, for instance mercury. The container d is held in proper position by a nut ndin through becoming effective 490,781, and'in Germanynecember 8, 1889.

'w. The parts (i and d consist preferably at least partly of a good conductor of heat, for instance copper, which is in intimate contact of the liquid substance enclosed in them; At-

the closed end of the tubular spring is an e e e u that is subjected to the action of a helical sprin i, the other end of which is attached to a hoe h. .The eye 6 has an oblong slot 0' through which extends a bolt 9 that is connected with one end of the leaf spring f. Near so the place of connection of the eye c with the leaf spring f this latter passes through between two abutment members formed by edges or wedges c and In between which said spring can turn or oscillate like a two-armed lever. To the free end of the leaf spring is attached a contact piece Z which may be ball-shaped and co-operates with a concave contact member m which it has engaged in the position 7 shown in Fig. 1.

The contactpiece or member m is connected with a bracket 0 by means of a helical spring" 11, and this bracket is fir secured-to the base late a, an insulatingpiate at "being provided between these two parts 3 is a screw for connecting up one of the conductin wires, and g denotes a pivot extending fort from the base plate and supporting a two-armed lever r, one arm of which is forked and provided with two pins 8 and t, the arrangement of which relatively to the leaf spring is such that this latter passes through between them. The other end of said lever 1* which is preferably rounded lies over the ends of two small leaf springs 10 and c which are secured to the base plate' and extend obli uely from the same to opposite directions w ich appears from Fig. 2 which also shows that t ese springs cross one another.

The container d is closed at its lower end ,0

by means of a threaded plug p which serves for adjusting the switch by screwing it in more or less so as to act thereby. upon the tubular spring. In the position ,of the ingthe switch rises, the'liquid substance enmo closedinthepartsdandd'willexpend whereby a pressure is exerted upon the tubu- 1211' spring so that its free end moves to the right, in consequence whereof the main portion of the leaf spring (below the abutment members a and k) w1ll be bent to the left.

More precisely, said leaf spring portion will be bent through to the left, as its lower end is retained or checked by the small leaf sprlng ea. In the same measure in which the temperaleaves the contact piece m so that the current is broken. The released endv of thespring f flies forward with a'jerk so much that it gets behind the free end of-the other small leaf spring 4: by which it is then i checked and retained. If thereafter the temperature of the surroundin air decreases, as does consequently, also t e temperature of the liquid substance in the parts 4! and d, the tubular spring will contract and the large leaf spring f will now be bent through to the ri ht and will continue so until it contacts wit h the pint. Then the lever 1' will again be turned, the small leaf springo will be depressed, the large leaf spring will again be released and the contact members l and m. will again close the circuit, as. will now be clear without further details of the movementsand' the operation of the parts concerned.

The other conducting wire can be. connected with any desired part of the switch, especially the'base plate thereof, but if the current is not to flow through the switch said other wire can be connected with the contact member Z'by means of a flexible spring or the like, in which case this contact member must be insulated from the spring f.

I claim:

L-An automatic switch for electrically heatable implements, comprising, in combination witha closed receptacle enclosing a .liquid substance and being composed of a rigid vessel andof a practically semicircular tubular spring, firmly connected, and

communicating at one of its ends, with said vessel, this latter having a large diameter and being short in comparison with said tu-' bular spring; and vice versa, an elastic switching lever coupled with the other end of said tubular spring and being formed-of a leaf spring so arranged as to be adapted to be moved when the curvatureof said tubular 'springis changed; a contact piece -at the free end of said leaf spring; another contact'piece opposite said first-mentioned one; two smaller leaf sprlngs so arranged relatively to the first-mentioned leaf spring that one thereof is adapted to check this latter spring in one of its end positions, and. the other thereof is adapted to check the said first-mentioned leaf-spring in the other of its end positions; and a lever coupled with the first-mentioned leaf spring and adapted to depress the other two leaf springs alternately according to the position of the first leaf spring as determined by the said tubular spring, substantially as set forth.

I 2. An automatic switch for use in connection with electrically. heatable implements, comprising, in combination, a closed receptacle enclosing a liquid substance filling the receptacle, and being composed of a rig d vessel and of a practically semi-circular tubular vessel designed'as a tubular spring and bein at one of its ends firmly connected with, an communicating with, said rigid vessel, this latter having alarge diameter and bei short in comparison with said spring, an 7 viceversa; an elastic switching lever coupled with the other end of said tubular spring and being constituted by a leaf-spring so arranged as to be adapted to be moved when the curvature of the tubular spring varies; abutmentmembers located on the two sides of said leaf'spring and making it a two-armed lever;

a contact member at the free end of the leafand being inserted between it and said two 7 smaller leafsprings and being adapted to depress the n alternately, substantially and for the purpose set forth.

3. An automatic switch for use in connection with electrically heatable devices, comprising, in combination, a closed receptacle with a liquid substance therein and composed of a comparatively short and wide, rigid ve'ssel, and a circularly curved" elastic tube ;ex-

tending forth axially. from the rigid. vessel; and an elastic switching lever coupled with the free endof the elastic tube and being formed by a leaf spring; a rigid two-armed lever and pins pro ecti ng forth from one arm thereof, said leaf spring passing through between said pins; :twosmaller leaf springs located below the other arm of said rigid lever and being so arranged with respect thereto as to be adapted .to be depressed alternately by the same according to the position of the first-mentioned leaf spring as determined by the said tubular spring; a (ontact member attached to the free end of said first-mentioned leaf-spring, and another contact member arrangedopposite to said first contact member and being in contact with it at one of the two end positionsof said leaf spring, as set forth.

In testimonywhereof I aflix'my signature. GUSTAV SGHAFER.--

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