An Automatic Electric Circuit Breaker.
Year: 1892

page_text: Date of Application, 23rd Jan., 1892-Accepted, 27th Feb., 1892
COMPLETE
SPECIFICATION.
An Automatic Electric Circuit Breaker.
I, ANTON EICHLER, of IV Belvederegasse, Belvederehof 8, Vienna, in the
Empire of Austria, do hereby declare the nature of this invention, and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
This invention relates to an automatic electric circuit breaker so constructed as
to break the circuit upon the potential or the intensity of the current unduly
increasing, or exceeding a certain fixed limit.
My automatic circuit breaker consists essentially of a metallic strip, preferably
slightly bent at its middle part and secured at both its ends by set-screws; this
strip electrically connects the terminals of the breaker, and the curvature of the
same increases under the action of the heat as soon as the intensity or the potential
of the current rises above the normal, the effect of which extension is to release a
lever on which the metallic strip is fastened, the aforesaid lever being subsequently
swung upward by the action of a spring or of a counter-weight, and the circuit
being thus interrupted.
To enable my invention to be fully understood I will describe how it can be
carried into practice by reference to the accompanying drawing, in which :-
Figure 1 is a sectional elevation of an automatic circuit breaker constructed
according to my invention, the apparatus being shewn in its normal position in
which the circuit is closed :
Figure 2 is a similar view shewing the position of the parts when the circuit has
been broken:
Figure 3 is a plan of Figure 1.
As shewn in Figure 1, the metallic parts which are connected to the terminals P¹
and P3 of the apparatus are brought into electrical communication with each other
through the medium of a metallic strip a, widened at its extremities a' and a² which
are fastened by means of set-screws and 62 to the upper face of a lever e made
of wood or of any other suitable non-conducting material. The lever c is provided at
both its ends with shoes c¹, c² which are in contact with the ends a', a² of the metallic
strip.
When the circuit is closed, the shoe crests in a corresponding metallic recess p
which is electrically connected to the terminal P₁, whereas the shoe c³, acting as a
hinge for the lever c, is supported by a bearing p' in which is screwed the
terminal P
It is advantageous to provide notches d, d and d in the metallic strip, the
notches d, d being near the set-screws 61, 62, and the notch d' at its middle or bent
part. These notches have the effect of reducing the thickness of the strip at the
above mentioned points, and consequently of causing the quicker and easier bending
of the same when the metal becomes heated.
The bearing p has a lug or bracket p³ in which works the pivot fl of the
disengaging lever f, the latter resting, through the medium of a set-screw f³, on the
part of the strip a.
The object of this lever f is to maintain the lever c, when the circuit is closed,
in the position shewn in Figure 1, and it is provided for that purpose with a heel f³
pressing against a projection c³ of the lever c, the latter thus being prevented from
being swung upward by the action of the spring g acting on the under face of same
(or by the action of a counter-weight used to the same effect).
As shewn in Figure 1, when the circuit is closed, the lever c bears by means
of its shoe cl against the metallic recess p', in such a manner that the current,
entering at the terminal P¹, passes through the switch in the direction shewn by

page_text: the arrows to the terminal P. The moment the intensity or the potential of the
current is in excess of or rises above a predetermined limit, the resulting higher
temperature causes the strip a to become more bent or curved, thereby raising the set-
screw resting on it, which causes the disengaging lever to move upward until
its heel ceases to engage with the projection 3. At this moment, the lever c,
being released, is suddenly swung upward by the action of the spring g into the
position shewn in Figure 2 and the circuit is interrupted.
The regulating screw 2 allows of adjusting the position of the lever fin relation
to the metallic strip, thereby ensuring the continuity of the current until the fixed
degree of temperature is reached.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. An automatic electric circuit breaker, the chief feature which is a metallic
strip a, slightly bent, and fastened at both its ends, and carried by a non-conducting
lever c, the said strip, when the circuit is closed, forming an electric connection
between both terminals, whereas upon the intensity or the potential of the current
exceeding the normal, the said strip becomes further bent by the increase of tem-
perature and releases the disengaging lever which maintains the arm c in its
lowered position: the latter being consequently swung upward by the action of a
spring or of a counter-weight, thereby causing the rupture of the circuit, substan-
tially as hereinbefore described and illustrated in the accompanying drawing.
2. In the automatic electric circuit breaker described in the first claim, a metallic
strip a, in which notches d, d are provided, close to its fastened extremities, and a
notch dat its middle part or bending point for the purpose of facilitating the
bending of the strip, substantially as hereinbefore described and illustrated in the
accompanying drawing.
3. In the automatic electric circuit breaker described in the first claim, a disen-
gaging lever f, the heel of which engages, when the circuit is closed, a projection c
on the lever c, thereby maintaining the latter in its lowered position; the position of
the lever in relation to the metallic strip a being regulated by means of a set-
screw for the purpose of regulating the desired limits of the continuous flow of
the current, substantially as herein before described and illustrated in the accom-
panying drawing.
Dated the 23rd day of January 1892.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.