Improvements in or relating to Electromagnets for Use in Relays, Sounders, and other Electromagnetic Apparatus.
Year: 1899

page_text: Date of Application, 14th Nov., 1899-Accepted, 13th Jan., 1900
Improvements in or relating to Electromagnets for Use in Relays,
Sounders, and other Electromagnetic Apparatus.
I, JAMES LYMAN CUTLER, Electrician, of No. 20, Broad Street, City of New
York (Borough of Manhattan), County and State of New York, United States
of America, 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 certain improvements in electro-magnetic appli-
auces particularly adapted to be used in relays, sounders and the like, and has
for its object to provide instruments of a simple and inexpensive character,
which shall be strong and durable and of such construction as to admit of their
being operated with a minimum of electro-motive force, so that an economy
in current is permitted.
The invention is also intended to lower the "time constant" of the apparatus
by reducing the self-induction of the electro-magnet and thereby to secure a
more rapid and lighter acting instrument than those in general use.
"
These objects are obtained by employing electro-magnets of the "iron-clad
variety and destroying therein the continuity between the iron core within the
coil and the iron portions outside of said coil, and also by destroying the con-
tinuity of the armature, whereby the magnetic circuit is broken or rendered
imperfect.
By those means such apparatus is rendered more highly eficient and constant
in operation, inasmuch as it becomes practicable to use instruments of compara-
tively small resistance, and therefore of less susceptibility to the disturbing
effects of the line variations, or current fluctuations, especially in heavy or stormy
weather.
In the accompanying drawings, I show in Figures 1, 2 and 3, a relay or
receiver embodying my improvements.
Figure 1 is a side elevation of the apparatus, part of the shell being broken
away; Figure 2, a section along line 2-2 in Figure 1 looking in the direction
of the arrows, and Figure 3 an elevation of the arinature showing that side which
faces the magnet.
Figure 4 is a side elevation of a sounder likewise embodying my improve-
menta.
Referring to Figures 1, 2 and 3; 10 indicates a base usually made of wood
and iron and carrying binding screws 11 and 11' placed in pairs in the usual
manuer, from which screws, wires lead to the coil of the electro-magnet and to
the armature in the usual manner. 12 is a frame of brass or other suitable
material, mounted upon base 10 and carrying at its top a horizontal bracket 13,
haring a downward projecting arm 14. 15 is an upright post on base 10, for
the support of the electro magnet.
Said electro-magnet comprises a core 16, a magnet coil 17, wound thereon,
and a slotted, tubular, soft iron shell 18, covering said coil, and which at its
end nearest to post 11, is closed by a disk 19, made of soft iron.
At the oppo-
site end of the electro-magnet is placed the armature 20.

page_text: The electro-magnet is held in position upon supports 12 and 15, and is guided
as follows:
21 is a brass rod passing through post 15 and disk 19, and having screw threads
at both ends, one end being screwed into the end of the core adjoining said disk,
a shoulder being provided on said rod, which rests against the outer surface of
said disk. 21' is a nut in engagement with the other end of rod 21, and abutt-
ing against post 15, whereby the electro-magnet may be adjusted to and from
the armature. 22 is a spring around rod 21, and interposed between post 15
and disk 19 for normally forcing the electro-magnet towards the armature.
Core 16 is separated from direct magnetic contact with disk 19, by a small
disk of mica or other non-magnetic material 23, placed around brass rod 21
between disk 19 and said core.
Frame 12 has a circular opening into which shell 18
has on opposite sides, two longitudinal slots, 24 and 24.
tending from frame 12 into slot 24.
fits easily. Said shell
25 is a guide pin ex-
Armature 20 consists of the usual armature lover 20, made of brass and hinged
to bearings 27, on bed plate 10. Said lover is constructed in the form of a disk
of a diameter corresponding with the outer diameter of shell 18, it having a
lug, 28, upon its lower edge for hinging it to bearings 27, and a projection 29
at its upper edge, which projection carries a small platinum contact pin 30.
The face of said lever nearest to the electro-magnet carries the soft iron
parts 31, 32 and 33, which form the armature proper and are riveted to the arma-
ture lever and separated from each other by narrow gaps, as shown in Figure 3;
31 being a central disk and 32 and 33 halves of an annular body surrounding
disk 31, the position of parts 32 and 33 corresponding with the portions of
shell 18, as divided by slots 24 and 24. For different constructions of the elec-
tro-magnet, different configurations of the parts forming the armatures may be
selected and the gaps between the different iron portions may be filled with mica
or other non-maguetic substance.
Near the free end of bracket 13, an adjusting pin 34, passes downward through
the same so as to bring its lower portion opposite to the center of the armature.
Around said lower portion, a cord 35, is wound to which is attached one end of
a retractile adjusting spring 36, the other end of said spring being secured to
a look 37 on the outer surface of the armature lever. 38 is a contact screw ex-
tending through frame 12 and provided with a platinum contact pin 39 adapted
to engage with contact pin 30.
40 is an adjusting screw passing through arm 14, and provided with a carbon
point 41, such screw in conjunction with screw 38, being adapted to limit the
inovement of the armature.
The improved relay is adjusted and controlled, practically the same as those
now in use; its novel features of construction and operation being as follows:
Shell 18 is practically a continuation of core 16, and hence constitutes a mag-
netic return or path of small reluctance to the magnetic lines of force created by the
working currents. As a result thereof a much more powerful magnetic effect is deve-
loped in core 16 than would otherwise be the case, but in order to minimize
the magnetic inertia and thus increase the rapidity of action of the instrument
the continuity of the magnetic circuit is broken by brass rod 21, and the mica
placed around it, between the core and disk 19, and by constructing the arma-
ture in sections separated by air gaps as described.
Slots 24 and 24 tend to destroy the magnetic eddy currents.
The rise and fall of magnetism in an instrument so constructed, is much more
rapid than would otherwise be the case, while the amount of residual, or remanent
magnetism, which in ordinary electro-magnets tends to impair the legibility of
signals, is very much reduced. And for this very reason, it is practicable to main-
tain the armature in close proximity to its core through a considerable range of
magnetic values, whereas an ordinary electro-magnet would require to be fre-
quently readjusted under similar conditions.

page_text: The telegraphic sounder illustrated in Figure 4, embodies an electro-magnet
of corresponding construction; 17 being the coil which surrounds the core,
18 the outer shell and 20 the armature. The electro-magnet carries a frame 12*
upon which the armature lever 20 is pivotally mounted, and also the usual ad-
justing apparatus.
It will be obvious that the electro-magnet forming the subject of my inven-
tion in form and arrangement is capable of considerable modification without
departing from the spirit of my invention.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what
I claim ie:-
1. In an electro-magnet, the combination of a core, a coil wound thereon,
an exterior iron body, and a non-magnetic substance interposed between said
core and said body.
2. In an electro-magnet, the combination of a core, a coil wound thereon, an
exterior body comprising iron bars extending along said coil, and a connection
between said bars and said body, a portion of which is made of iron and a por-
tion of non-magnetic material.
3. In an electro-maguet the combination of a core, a coil wound thereon, an
exterior iron body comprising a disk placed opposite one end of the core and a
slotted tube extending from said disk along the coil, and a non-magnetic screw
for securing the disk to the core, a piece of mica or another non-magnetic sub-
stance interposed between said disk and said core.
4. In an electro-magnetic appliance, the combination with an electro-maguet
comprising a core, a coil wound thereon, an exterior iron body, and a non-mag-
netic substance interposed between said core and said body, of an armature placed
within the field of said magnet.
5. In an electro-magnetic appliance, the combination with an electro-magnet
comprising a core, a coil wound thereon, an exterior iron body and a non-magnetic
substance interposed between said core and said body, of an armature placed
within the field of said magnet and comprising bodies of iron separated from
each other.
6. In an electro-magnetic appliance, an electro-magnet comprising a core, a
coil wound thereon, an exterior iron body consisting of a disk placed opposite
one end of the core and a slotted tube extending from said disk along said coil,
and a non-magnetic sciew for securing the disk to the core, a piece of mica
or another non-magnetic substance surrounding a portion of said screw, all com-
bined with an armature placed within the field of said magnet and comprising
bodies of iron soparated from each other and corresponding in their general
configuration substantially with the configuration of the end portions of the
electro-magnet forming its poles.
7. In an electro-magnetic appliance, the combination with an electro-magnet,
comprising a core, a coil wound thereon, an exterior iron body and a non-mag-
netic substance interposed between said core and said body, of a hinged armature
within the field of said magnet, a retractile spring attached to said armature,
and a frame for supporting the electro-magnet and provided with a bracket
carrying stops for limiting the movement of the armature.
Dated thie 13th day of Yovember 1899
CRUIKSHANK & FAIRWEATHER,
Chartered Patent Agents, 02, Saint Vincent Street, Glasgow,
Agents for the Applicant.