Improvements in Automatic Switches for Electrical Apparatus.
Year: 1892

page_text: Date of Application, 11th Apr., 1892-Accepted, 14th May, 1892
COMPLETE SPECIFICATION.
Improvements in Automatic Switches for Electrical Apparatus.
I, Albrecht HEIL, of Fränkisch-Crumbach, in the Empire of Germany, 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 a species of automatic switches for use with electric
lamps and other electrical apparatus where the necessity exists that a circuit.
which has been in any way broken, either by accident, mistake, or injury, should
as rapidly as possible be substituted by another, into which is interposed an
electric arrangement, for a purpose equal or similar to that of the arrangement
which has become useless by reason of interruption.
To enable my invention to be fully understood I will describe the same by
reference to the accompanying drawing.
The new self-acting switch is distinguished by a two-armed metal lever H h,
which is kept in a fixed position by a strained wire d so long as no current
passes through it, and in this position allows one of the conductors to be brought,
into the circuit of a source of electricity by means of a switch-lever S Figure 1.
If however a current passes through the strained wire d the latter in consequence.
of its small diameter becomes heated to such an extent that it yields considerably,
and in consequence allows a spring so to turn the lever Hh that the
arm H of the latter is switched into the circuit in which the wire d is placed,
so that the latter is not further heated and remains at the same temperature, as.
the result of which the lever arm H is retained securely in its new position.
As soon as the circuit which includes the wire d, and also in the above case
the lever arm H is interrupted by any means, the wire cools, and in consequence.
contracts and overcomes the pressure of the spring, so that the lever Hh,..
revolving, returns to the position which it had quitted when the wire d was
brought into the circuit, and in which as above stated it allows a second con-
ductor to be switched into the circuit by means of the lever switch. S or of a
suitable equivalent of the latter. This act is as a matter of fact no longer
necessary if the wire d were previously in circuit, because the lever-switch S. or
its equivalent in this case takes. the same position which it is taking in order to
switch the second conductor into the circuit, and in which position it serves to
connect the whole automatic switch with a source of electricity or to exclude it
from current.
In order that the arrangement may be more easily understood, in Figure. 1
is. shewn, as an example of the employment of the automatic switch, an incan-
descent lamp suspended from it, which possesses two incandescence filaments. a
and 6 the connecting wires 1 and 2 of which are branches of a common conductor I
whilst their connecting wires 3 and 4 are connected to metal plates m' and. m*
of which one carries a metallic screws with which the spring fis in contact.
if the automatic switch is excluded from the current and is in contact again,.
when, after the automatic switch having been included in current the circuit. in
which the wire d lies is broken.
In the instance under consideration this latter circuit is the one marked 2
and 4, being connected by means of the metal plate m² with the pin of the lever H
and by the latter with the wire d, in one circuit.
There is no direct conducting connection between the lever arm H and the metal.
plate m¹ because the spring does not press directly upon the lever arm H,, but
upon a rod or other body of insulating material.

page_text: In order, in the arrangement shewn in Figure 1, to shunt the automatic switch
into the current, the switch lever S is turned to the right, and thereupon the
spring is pressed against a metallic rod t which is secured to the metal plate m
to which is connected the return conductor II of the source of current. If the
switch lever S is turned to the right there is set up by means of the metallic
springs ff a conducting connection between the screw's and the rod t, together
with a similar connection between the conductor 3 and the return conductor II, and
also because the double spring f'f' is secured to a metallic plate mt on which the
wire d is fastened and because the latter is connecting this plate conductively with
the lever arm h, being connected with the conductor 4 by the metal plate m². The
spring is connected conductively with the conductor 4 and, since the spring fis
now brought into contact with the rod t, the conductor 4 is by means of the
spring brought into circuit with the return conductor I I.
By the described construction of the automatic switch, the doubled spring f',ƒ'
does as a matter of fact connect and complete the circuit between the conductors 3
and 4, but only for an instant, that is to say, the instant when the automatic switch
is shunted into the circuit of the source of current. At this instant both the
incandescence filaments a and b of the incandescent lamp give light, but as the
current for one of these that is to say, for the filament 6 traverses the wire d
the latter becomes heated and as above described, causes the spring 1 to turn the
lever Hh so that the lever arm H comes into contact with the screw a¹ and sets up
a better connection between the plates m² and m³. In this turning movement the
spring floses its contact with the screw s, and so the conductive connection between
the conductor 3 and the return conductor II is interrupted and the filament a is no
longer in the circuit of the current and ceases to glow. On the other hand it will
at once become incandescent again as soon as the filament b is extinguished, because
the wire d in this case growing cold, will bring the spring f' into contact with the
screw s again.
Figures 2 to 5 are views shewing the details of a modification of the above described
automatic switch in employment within the fastenings of an incandescent lamp in
which by pushing up a connection-shell the spring f2 is conductively connected with
the spring and thus is effected once for all the same object which is in the method
of construction shewn in Figure 1, brought about by turning the switch lever S to
the right.
The prolongations of the spring f³ (Figure 3) and the springs g and which are
soldered to the metallic plates m' and m serve for connections to the three con-
ductors 3, 4 and 11 which end in spring-pieces within a case o and being insulated
from each other, are, for the purpose of connection with the three springs f³, g and k
(which are also well insulated from each other) simply pushed in the wooden block
of the case o between the outrunners of the last named springs and the adjoining
insulating blocks 1.
In this arrangement the metal plate m³ is replaced by the spring f³.
As the parts of the self-acting switch in this construction bear the same letters as
the corresponding parts of the switch shewn in Figure 1 a detailed explanation of
Figures 2, 3 and 4 is not required.
Figure 5 shews a compressing spring / inserted in the wood block p and catching
into a notch in the rod v soldered onto the casing o to ensure the connection between
the case o and the principal parts of the apparatus.
Figure 6 shews another modification of the automatic switch in which provision is
made for excluding the conductor 4 by hand from the circuit, and connecting the
conductor 3 alone to the apparatus, so that the latter then operates like an ordinary
switch. If the lever switch S turns to the right so that its nose comes into contact
with the spring the apparatus then is substantially identical with the one shewn
in Figure 1, as is made apparent by the employment of the same letters as in
Figure 1 for the corresponding parts.
Finally, Figure 7 shews a modification of the automatic switch in which the lever
switch is dispensed with so that the conductor I must be connected up directly to

page_text: the metal plate mt. Here also the letters employed are the same as those used in
Figure 1 for the corresponding parts.
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 switch distinguished by a two-armed lever (H h) and a wire (d).
which is so connected with the lever (HA) and with a fixed metallic plate (m) that.
it keeps the former in a fixed position in which one lever arm keeps a spring f1, and
closing the circuit of a two-branched conductor (3 and 4) as long as it (the wire) is.
not heated by a current passing through it, whilst in case of such heating the
spring (1) will turn the lever Hh, and interrupt the connection just referred to
with one of the two aforesaid branched conductors whilst at the same time the lever
arm (H) which is supported by the spring (f') passes entirely into the circuit in
which the wire (d) lies, in order to prevent the latter from being heated too strongly,.
substantially as hereinbefore described and illustrated in Figure 1 of the accom-
panying drawing.
2. The three modified arrangements of automatic switch substantially as herein-
before described and illustrated in Figures 2 to 5, Figure 6 and Figure 7 respectively
of the accompanying drawing.
D1
1
3000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.