Year: 1886

page_text: I ALEXANDER BERNSTEIN, of N° 9ª, Commercial Road, Pimlico, in the county of
Middlesex, Electrician, 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:-
My invention relates to certain improvements in electric switches intended to be
used in electric circuits, such as those in which a large number of devices, such as
glow lamps, are arranged in series on one common conductor.
The improved switch is adapted for use wherever an electric device is to be
included in or excluded from the main current and it is especially suitable for
use in connection with a system of electric lighting such as is described in the
Specification of my former English Letters Patent No 6,075 dated the 20th December
1882. In electric lighting circuits such as are referred to in the specification of my
said former Letters Patent a switch is required wherever the current enters and
leaves a house to be lighted, and in describing my improved switch I shall suppose
the same to be used in a place which requires that the switch shall serve the
following purposes, videlicet:-
To allow the house circuit to be passed by the current or a short circuit_to be
made in order to prevent the current from passing through the house. In the
latter case it is further desirable that the house circuit shall be entirely disconnected
from the main circuit so that any repairs or alterations can be effected inside the
house without danger even if the main circuit should have a defective insulation.
It is morever necessary to prevent any interruption of the circuit in case the
house circuit is not complete at the time at which it is intended to turn the current
into the same, and the attainment of this object is the main feature of my
invention.
For this purpose I arrange the switch in such a manner that the switch lever,
after leaving the "off" position in which the house circuit is short circuited, and
before coming into the "on" position in which the current would pass through the
house can take an intermediate position in which the main current will divide
itself into two branches, one part of the current passing through a permanent
resistance connected with the switch and the other part passing through the house
circuit, if the same is complete.

page_text: If the latter be the case, then the current in the house circuit will excite an
electro magnet, the armature of which is attracted. This armature, if it were not
attracted would interfere with a further movement of the switch lever from the
said intermediate position, and in this way the lever is prevented from coming into
the "on" position except when the house circuit is complete.
In order to enable my invention to be fully understood I will proceed to describe
the same by reference to the accompanying drawing in which figure 1 represents a
plan of an electric switch constructed according to my invention and figure 2 is a
cross section on line 2, 2, of tigure 1.
u, represents a circular box of insulating material, on the upper edge of which
three contact pieces or strips of metal b, c, and d, are fastened; l, is the switch
lever, made of metal. This lever turns on a central pivot and can occupy three
different positions, indicated in figure 1 by the dotted lines 1, 1, 2, 2, and 3, 3,
respectively.
In the position marked 1, 1, the lever l, connects the strip b, with the strip d;
in the position marked 2, 2, the strip c, is connected by the lever 1, with the
strip d; and in the position marked 3, 3, the lever l, rests on insulating pieces at
both ends.
e and f, are two flat springs of metal, the free ends of which rest respectively on
the strips band d; these springs are in practice generally placed concentric with
the top edge or rim of the box a, but are shown in the drawing placed at an angle
thereto for the sake of clearness.
The lever l, as shewn in figure 2, carries on its upper side at its two ends the
pieces of insulating material y and h. When the lever l, is placed in the position
marked 1, 1, as herein before described it connects the strip b, with the strip d,
and as the strip b, forms one terminal of the main circuit q, and the strip d, forms
the other terminal thereof it follows that the two ends of the circuit are then
directly connected.
The spring e, forms one terminal of the house circuit o, and the spring f, forms
the other terminal of the same. When the lever l, is moved into the position
marked 1, 1, it lifts the spring e, from the strip b, and the spring f, from the
strip d, thereby causing the two springs e and f, to rest on the two pieces of
insulating material h and g, respectively attached to the ends of the lever l, and
the house circuit o, will be entirely out of electrical connection with the main
circuit q.
In order to prevent any interruption in the circuit in case the house circuit should
not be completed as herein before mentioned I connect the two contact pieces b
and c, with each other by means of a permanent resistance piece r, which
represents a certain part of the resistance of the house circuit o.
This latter circuit o, includes an electro-magnet m, which is placed inside the
box a, as shewn. The armature n, of the electro magnet m, carries a pin p, which
is placed in such a way, that if the armature be not attracted, the pin p, will be on
a level with the lever ; but if the armature be attracted, then the pin will be
below the lever l, and will not prevent the free movement of the lever.
If then the lever 1, be placed in the intermediate position marked 2, 2, part of
the current will pass through the permanent resistance piece r, and part will pass
through the house circuit o, if the same is complete; consequently the armature n,
will be moved downwards and the lever l, can now be moved into the position
marked 3, 3, in which position it will be entirely insulated and the whole current
will then pass through the house circuit o.
If however the house circuit o, had been interrupted it would have been
impossible to move the lever 1, into the position marked 3, 3, and a break in the
main circuit q, would have been in this way prevented.
Instead of employing the electro-magnet m, any other suitable known device
such as a galvanometer can be used which merely indicates the existence of a
current in the house circuit o, thereby showing that the lever l, should not be
moved into the position marked 3, 3,

page_text: The switch, which I have described as a main house switch is also adapted to be
used in connection with every single electric device, such as glow lamps or other
like devices which are placed in the house circuit.
Although the lever 2, is here shewn as moving in a circle, it is obvious that a
slide may be used moving in a straight line or in any other direction which will
allow of producing the desired result.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
1. In an electric switch the combination with a permanent resistance arranged
to act as a temporary pass for the main current, of a suitable electro-magnetic
device such as that herein described for indicating a current in the circuit which is
intended to be included in the main circuit as herein before described.
2. In an electric switch the combination with a permanent resistance arranged
to act as a temporary pass for the main current, of an electro-magnet the armature
of which operates so as to prevent further movement of the switch lever in case of
interruption of the circuit which it is intended should be included in the main
circuit as herein before described.
3. The combination of parts forming the improved electric switch herein before
described and represented in the accompanying drawing.