IMPROVEMENTS IN TELEGRAPHIC RELAY APPARATUS
Year: 1884

page_text: I, JOHN GRAHAM, of N° 16, Belmont Street, Haverstock Hill, in the county
of Middlesex, Electrician, do hereby declare the nature of said invention for
"IMPROVEMENTS IN TELEGRAPHIC RELAY APPARATUS" to be as follows:-
The object of my invention is to afford increased facilities for receiving
telegraphic communications over short or very long distances, by means of a
novel arrangement of electric apparatus, especially designed to be susceptible to
the influence of feeble, or very minute, electric currents.
п
For this purpose
employ a set of electro-magnets so arranged that their
alternate, or positive and negative, poles closely face one another, and are by
the reciprocal and multiplied action thus produced, rendered' very sensitive,
consequently greatly increased effects are obtained.
The said set consists of the combination with one another of an electro-magnet,
or electro-magnets, fixed and stationary, and acting upon, and being acted upon,
by an electro-magnet, or electro-magnets, affixed to a pivoted vibrating armature,
or armatures; Said armatures being provided with a suitable make and break
contact piece for opening and closing a local circuit, in which is inserted a galvanic
battery, and a switch for bringing in an ordinary Morse sounder, or a call bell, as
may for the time be required.
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"
In order to obtain still greater intensified effects, I employ permanent magnets
instead of the said electro-magnets, such permanent magnets being provided with
iron pole-pieces, or ends, around which are placed the receiver coils:
The said pivoted vibrating armatures need not necessarily carry, or be provided
with, receiver coils; but may, in some cases, simply act in response to the influence
of the stationary electro-magnets, or permanent magnets, only.
To control, or regulate, the action of said apparatus, I employ permanent
magnets acting upon the reverse side of the vibrating armatures, and provided
with receiver coils, so arranged that upon the reception of an electric current the
attraction of the magnets upon the armatures is diminished, in consequence of
which the armatures are caused to respond more freely.

page_text: The contact piece J is affixed to and projects from the end of the armature in
this instance, and acts between two contact screws, upon making contact against
either of which, the local circuit is completed, precisely in the same manner as in
fig. 1. There are four spiral tension springs employed, by means of which, the
action of the armature and contact piece J is regulated between the two contact
screws. .
I will now describe the action of my relay apparatus shown in fig. 2 when it is
actuated by the reception of a positive current. The current enters LINE and
passes on through the transmitting key k; through the coil C of S pole of the
magnet M; through the coil Cs of N pole of the magnet M; through the coil Ơ
of N¹ pole of the magnet M'; through the coil C of S¹ pole of the magnet M¹; and
Bo on, following the course of the connecting wires to the earth plate e. The effect
of the passage of a positive current through the coils as just described, would be to
decrease the attractive-influence of the poles of the magnet M upon the moveable
armature; to increase those of M'; to decrease those of M'; and-to-increase_those_
of M; consequently the armature would be drawn over toward M¹ at the one end,
and toward M at the other; the contact piece J would be brought in contact with
the screw suppord by the pillar L'; thus closing the local circuit. Upon the
reception of a reverse, or negative, current the armature would be drawn over to
the opposite side, and the contact piece J would then be brought in contact with
the screw supported by the pillar L, thus again closing the local circuit, as the two
contact screws L' and L' are electrically connected together.
Refering to fig. 3. B, B and B¹, B and C, C and C¹, C are electro-magnets
connected up in the line circuit; and D°, D° is an electro-magnet inserted in the
local circuit. The armature is, as in fig. 2, composed of two bars of magnetized
steel, joined together at their inner ends by a piece of unmagnatizable metal E.
The stop pins R and R¹ are so adjusted that when the armature is at rest its
poles, N, S and S, N, are nearer to the cores of the electro-magnets C, C and C¹, C¹
than they are to those of B, B and B¹, B¹; in consequence of which it is drawn
over and bears lightly against the stop pin R, by the greater attraction of its
poles N, S and S, N upon the cores of C, C and C¹, C'; But, immediately upon
the reception of a positive current from the distant station, the core of the first
coil of C¹, C' is polarized negatively, or N; that of the second coil of C₁, C¹
positively, or S; that of the first coil of B, B negatively, or N; that of the second
coil of B, B positively, or S; that of the first coil of C, C negatively, or N; that of
the second coil of C, C positively or S; that of the first coil of B¹, B¹ negatively,
or N ; that of the second coil of B¹, B¹ positively, or S; The result is, the
electrically induced cores N, S of the coils C, C¹ repel the similar, or N, S, poles of
the armature; the induced cores N, S of the coils B, B attract the dissimilar,
or S, N, poles of the armature; the induced cores N, S of the coils C, C repel the
similar, or N, S, poles of the armature; and the induced cores N S of the
coils B', B' attract the dissimilar, or S, N, poles of the armature. The armature is
drawn over towards the stop pin R¹, and the contact piece J is brought into
contact with the screw K of pillar L, which closes the local circuit, as fully
described in reference to fig 1. In communicating over very long distances, such
as my improved relay is more especially intended for, it is necessary to have the
receiver coils wound with a much greater length of fine wire than usual, in order
to increase the effect of the unavoidably enfeebled current upon the cores as much
as possible; but in proportion to the greater length of wire used, there is an
amount of retardation of current in the coils, and residual magnetism in the cores;
to overcome the latter, I employ an electro-magnet to act in opposition to the
influence exerted by the received current upon the cores of the receiver coils,
sufficently powerful to release, or repel, the armature when the received current
ceases, but not quite strong enough to effect it while the current lasts. This
counteracting magnet may either be automatically shunted into circuit with the
line so as to intercept part of the line current immediately the armature of the

page_text: receiver is drawn over against the contact point, or placed in the local circuit as
hown in the figure.
Fig. 4. is a modification of fig's. 1 and 2.
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
[ claim is:
First. In electric telegraph apparatus, the combination of electro-magnets acting
upon and being acted upon by electro-magnets affixed to a moveable
armature substantially as shown and described in reference to fig. 1 of the
accompanying drawings.
Second. In electric telegraph apparatus, the combination of permanent magnets
acting upon a double magnet armature in manner and for the purpose
substantially as shown and described in reference to fig. 2.
Third. In electric telegraph apparatus, the combination of electro-magnets acting
upon a double magnet armature in manner and for the purpose substantially
as shewn and described in reference to fig 3.