A New or Improved Device for Automatically Effecting the Breaking of an Electric Circuit after a Predetermined Time.
Year: 1899

page_text: Date of Application, 17th Apr., 1899
Complete Specification Left, 17th Jan:; 1900-Accepted, 17th Feb., 1900
A New or Improved Device for Automatically Effecting the Breaking
of an Electric Circuit after a Predetermined Time.
I, HENRY EDMUNDS, of 2, Queen Anne's Gate, in the City of Westminster,
Electrical Engineer, do hereby declare the nature of my invention to be as
follows:-
My invention has for its object to provide a simple and efficient device whereby
an. electric circuit can be automatically broken..after a predetermined time so
that for instance after an electric lamp has. been. burning for a given time, it
will be automatically extinguished. Such an arrangement will for instance, be
useful in lavatories,. or. the like, to prevent a lamp being left lighted for any
considerable time if a person should leave the..lavatory without extinguishing
the lamp, but the invention is applicable generally in cases where it is desirable
to provide means for automatically breaking an electric circuit after a given
lapse of time. I will describe my invention as applied to an electric lamp from.
which its general application will also be understood.
In, proximity to the poles of a permanent magnet I arrange an armature
which is made of a material which becomes non-magnetic, or whose magnetic
properties are lessened, when it is heated, a suitable material is nickel, or an alloy
of nickel, such as nickel-steel. Around..this. armature.. I. wind a. thermic wire,
or conductor, such for instance, as a wire, or.conductor, of maganin, or of rheo-
stene covered with asbestos, or the like in the circuit which supplies current to
the lamp, or otherwise arranged so that current passes therethrough when current
passes to the lamp. When the lamp circuit is completed, the said, armature is
brought into such proximity to the poles of the permanent magnet that it is
attracted and held thereto, but when the current has been on for a predetermined
time the current passing through the thermic wire, or conductor, heats the said
armature to such an extent that it becomes non-magnetic, or its magnetic proper-
ties are lessened so that the permanent magnet no longer holds it in position
and it leaves the said poles, and in its movement it breaks the circuit to the
electric lamp and extinguishes it. The armature may itself be the switch by
which the circuit to the lamp is completed and broken. The period during
which the lamp will remain lighted before it is extinguished can be regulated by
adjusting the relative positions of the permanent magnet and the armature so
that the distance between the poles of the magnet and the armature is greater
the lesser is the time which it is desired shall elapse between the lighting and
extinguishing of the lamp.
1711
C A 1000
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.

page_text: coil of wire resistance in, or deriving current from the circuit so that when the
magnet core becomes sufficiently heated it will no longer attact the armature
and thus break the circuit.
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. For automatically breaking an electric circuit after a predetermined time
the combination therewith of a magnetic device in which is employed a material
whose magnetic properties are affected by heat and means for heating the said
material when the circuit is completed so that when the said material become's
sufficiently heated the circuit is broken substantially as herein before described.
2. For automatically breaking an electric circuit after a pre-determined time,
the combination of a magnet, and an armature, whose magnetic properties are
affected by heat, and means for heating the said armature by the current sub-
stantially as herein before described.
3. For automatically breaking an electric current after a predetermined time
the combination with the circuit and a magnet of a material such as nickel, or
nickel-alloy, around which is wound a wire of manganin, rheostene, or the like,
covered with asbestos, or the like, and in, or deriving current from, the circuit to
be controlled substantially as hereinbefore described.
4. A device for breaking electric circuits automatically after a predetermined
time arranged as hereinbefore described and illustrated in the accompanying
drawing.
Dated this 17th dor of Ionu 1900
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.