IMPROVEMENTS IN ELECTRO- MAGNETS
Year: 1883

page_text: LETTERS PATENT to Alexander Melville Clark of the firm of A. M and W.
Clark of 53 Chancery Lane in the County of Middlesex Fellow of the
Institute of Patent Agents for an Invention of IMPROVEMENTS IN ELECTRO-
MAGNETS communicated to him from abroad by Ludovic Charles Adrien
Joseph Guyot d'Arlincourt, of Paris, France
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 30th March 1883.
ALEXANDER MELVILLE CLARK of the firm of A. M. and W. Clark of 53 Chancery
Lane in the County of Middlesex, Fellow of the Institute of Patent Agents,
"IMPROVEMENTS IN ELECTRO-MAGNETS" [communicated to him from abroad by
Ludovic Charles Adrien Joseph Guyot d'Arlincourt, of Paris, France]
This Invention relates to improvements in electro magnets of the kind for which
previous Letters Patent were granted to the said Alexander Melville Clark as a
communication from Mr. Guyot d'Arlincourt on the 25th day of January 1872
No. 255 and which are known as D'Arlincourts' electro magnets.
The action of this electro magnet is based on the natural inversion produced by
the breaking of a current in the part of the electro magnet situated in rear of the
bobbins, that is to say, at the breech end, an armature or pallet polarised by one
of the poles of a magnet will be attracted therefore by the secondary pole existing
beneath the bobbins of the electro-magnet during the passage of the line current ;
on the breaking of this current the magnetism of the electro-magnet becomes
reversed and the pallet is forcibly repelled towards the other core.
This system of electro-magnet which is susceptible of application to all electrical
apparatus but principally as a telegraphic relay, thus comprised a single pallet
actuated by the secondary pole of the magnet.
The modification which forms the subject of the present Invention consists in
providing the apparatus with a second pallet placed at the extremity of the bobbins
and fixed on the same axis as the first pallet actuated by the rear or breech end
of the electro-magnet. They are thus rigidly connected and the simultaneous

page_text: operation of the two armatures can only occur upon condition that the polar pieces
between which the pallets move have opposite polarities. But in order that the
magnetic effects shall be opposite in the two polar pieces by which the combined
armatures are actuated, it is necessary that the electro-magnet be traversed by a
certain electro motive force. In the case of a weak current the polarity at the
rear or breech end is of the same name as that at the extremity of the soft iron
Consequently such a current cannot cause any mechanical action of the axis
of the armatures which in this case is influenced by a couple of forces which are
equal and opposite :
core.
The peculiar properties of these electro-magnets furnished with two combined
armatures are susceptible of immediate application to telegraphic cables for the
purpose of opposing the perturbative effects due to natural currents which traverse
them and whose intensity may thereby be diminished.
The currents will have no effective action on the two armatures except inasmuch
as they shall have attained the intensity necessary to effect the reversal of the
polarities at the breech or rear end contrary to the polarities existing at the
extremity of the core.
f
Although the form of the various parts and the details of arrangement of the
electro-magnet may vary without changing the nature of the invention I have
represented in the accompanying drawing two views of an example of an electro-
magnet or relay provided with these modifications.
Figure 1 is a front view and figure 2 a side view of the electro-magnet
The same letters of reference indicate the following parts in the two figures a, a¹
core of the electro-magnet, b breech end of the electro-magnet c, c bobbins
traversed by the line or other current, d, d¹ secondary poles acting on the pallet e,
f, f¹ soft iron polar pieces acting on pallet e¹, y axis common to the two
pallets e, e¹.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Melville Clark in the Great Seal Patent Office on
the 29th September 1883.
ALEXANDER MELVILLE CLARK of the Firm of A, M, and W, Clark of 53 Chancery
Lane in the County of Middlesex Fellow of the Institute of Patent Agents
"IMPROVEMENTS IN ELECTRO-MAGNETS A communication to me from abroad by
Ludovic Charles Adrien Joseph Guyot d'Arlincourt of Paris, France,
دو
This Invention relates to improvements in electro-magnets of the kind for which
previous Letters Patent were granted to the said Alexander Melville Clark
(No. 255 of 1872) as a communication from M* Guyot d'Arlincourt and which are
known as D'Arlincourt's electro-magnets.
The action of this electro-magnet is based on the natural inversion (produced by
the breaking of a current) in the part of the electro magnet situated in rear of the
bobbins, that is to say, at the breech end. An armature or pallet polarised by one of
the poles of a permanent magnet and placed between the secondary poles existing
beneath the bobbins of the electro magnet will therefore be attracted by one of
said secondary poles during the passage of the line current; on the breaking of
this current the magnetism of the electro-magnet becomes reversed and the pallet
is forcibly repelled towards the other secondary pole. This system of electro-
magnet which is susceptible of application to all electrical apparatus but principally
as a telegraphic relay thus comprised a single pallet actuated by the secondary
poles of the electro magnet.
The modification which forms the subject of the present Invention consists in
providing the apparatus with a second pallet placed at the free extremity of the
bobbins and fixed on the same axis as the first pallet situated at the rear or breech
end of the electro magnet this second pallet being magnetised by the other pole of
the permanent magnet. The two pallets are thus rigidly connected and of opposite
polarities and their simultaneous operation can only occur upon condition that the
polar pieces between which one of the pallets plays have opposite polarities to
those of the polar pieces between which the other pallet plays. But in order
that the magnetic effects shall be opposite in the two pairs of polar pieces by
which the combined armatures are actuated, it is necessary that the electro-
magnet be traversed by a certain electro motive force. In the case of a weak
current the polarity in one of the polar pieces at the rear or breech end is of the
same name as that at the extremity of the same branch of the soft iron core.
Consequently such a current cannot cause any mechanical action of the axis of tho
combined armatures which in this case is influenced by a couple of forces which
are equal and opposite.
The peculiar properties of these electro-magnets furnished with two combined
armatures are susceptible of immediate application to telegraphic cables for the
purpose of opposing or diminishing the perturbative effects due to natural currents
which traverse them
The currents will have no effective action on the two pallets except inasmuch as
they shall have attained the intensity necessary to effect the inversion of the
polarities at the breech or rear end contrary to the polarities existing at the free
ends of the core.
Although the form of the various parts and the details of arrangement of the
electro-magnet may vary without changing the nature of the invention I have
represented in the accompanying drawing two views of an example of an electro-
magnet or relay provided with these modifications.

page_text: Figure 1 is a front view and figure 2 a side view of the electromagnet. The
same letters of reference indicate the following parts in the two figures. a, a' core
of the electro-magnet, b breech end of the electro-magnet c, c' bobbins traversed by
the line or other current, d, d' secondary poles acting on the pallet e., f, f¹, soft
iron pole pieces acting on pallet el, g axis common to the two pallets e, e¹
Having described, the nature of the said Invention and the manner of performing
the same I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is:
In an electro magnet for use as a telegraphic relay and for other purposes the
combination with the electro-magnet, of a pair of armatures or pallets polarized
and rigidly combined as described and playing respectively between the poles at
the ends of the core and between secondary poles in rear of the bobbins,
substantially as shown and described for opposing the perturbative effects due to
natural currents traversing the electro magnet or relay as specified.
In witness whereof I the said Alexander Melville Clark, have hereunto set
my hand and seal this twenty ninth day of September A.D. 1883.
A
CIT AD IZ