Improvements in Apparatus for the Transmission of Telegraphic Messages by means of Direct or Alternate Electrical Currents.
Year: 1891

page_text: Date of Application, 28th Feb., 1891-Accepted, 2nd May, 1891
COMPLETE SPECIFICATION.
Improvements in Apparatus for the Transmission of Telegraphic
Messages by means of Direct or Alternate Electrical Currents.
A communication to me from abroad by DAVID KUNHARDT, of Aachen, in the
Empire of Germany, Engineer.
I, EDMUND EDWARDS, of the firm of Edwards & Co., Patent Agents and
Engineers, of 35, Southampton Buildings, Chancery Lane, in the County of
Middlesex, do hereby declare the nature of this invention and the manner in
which the same is to be performed to be particularly described and ascertained in
and by the following statement and accompanying drawings
This invention has for its object an apparatus for the transmission of telegraphic
messages, by means of which signs can be transmitted by direct currents of
electricity, that is to say-currents passing in the same direction, and earth con-
nections or by alternate currents, according to the interpositions of a contact plug,
the necessary relay being switched in after each sign.
In the accompanying drawings which are in illustration of the invention,
Figure 1 is a general view of an installation for direct and alternate currents,
Figure 2 being a separate view of a modification of the double lever illustrated
in Figure 1.
Figure 3 is a general view shewing separately the installation when the trans-
mission is effected by direct current.
Figure 4 is a general view shewing separately the installation when the trans-
mission is effected by alternate currents.
In Figure 1 the wires and clamps or binding screws common to both arrange-
ments are shewn in thick lines, whereas they are shewn in thin lines and the clamps
shaded, when the apparatus is operated by means of direct currents and earth
connections.
Furthermore the wires and clamps as well as the alternative position of rest of
one of the armatures of the electro magnets, are shewn in dotted lines for alternate
currents, whilst in order to shew more clearly the different arrangements and circuits
according to the two methods, these are reproduced separately in Figures 3 and 4.
Referring to Figure 1, H is a double lever or key having its fulcrum upon the
block, and carrying at one end the contact piece R¹, which forms with the contact
piece R, placed below it, a normal contact, the spiral spring X constantly holding
the lever arm down, whilst the other end of this lever or key is furnished with a
knob and a contact T', forming with the contact T placed beneath it the contact for
telegraphing a sign. The double lever or key H consists of two insulated pieces
which can be metallically connected together by means of the plug or stop S. For
operating by means of direct currents, that is to say currents proceeding in the
same direction, the plug S is interposed, whereby the key H practically consists of
a single solid piece, as shewn in Figure 3. Figure 2 shews a modification of the
construction and arrangement of the key H, as represented in Figure 1.
In the arrangement shewn in Figure 1 the + current of the local battery passes
through the spiral spring X and the normal contacts R, R, whilst the wire V
leading to the line or distance battery is connected to the block or support K of
the key H. In the arrangement shewn in Figure 2 the + current of the battery B
passes through the block K and the normal contacts R', R2, whilst the wire is
connected to the telegraphing contact of the key H.
When commencing operations with direct currents, all the binding screws
designated by Roman numerals are metallically connected with the several pieces G
having corresponding italic numerals. The local battery B then actuates the electro
magnet O, the current passing from the said battery to the spiral spring X (or

page_text: through the block K in Figures 2 and. 3), the key H, the normal contact R', R2.
the junction 2, the resistance U, proceeding round the electro magnet O and to
the junction Z of the negative current, and the electro magnet attracts its
armature a. The sign being now transmitted by depressing the key H, the electro
magnet releases its armature a' whilst the normal contact R1, R2, is opened and the
armature a' makes contact with the set screw or terminal «¹ of the inetal piece c.
This elastic metal piece which has the form of a flat spring as shewn, is fixed to
the pillar n, its outer end resting upon the rod which limits its motion.
The armature at which raises by means of the screw c¹ the spring c, is raised to
a sufficient height but is limited in its movements by the screw G. In the position
resulting from the release of the armature, the circuit is directly connected to earth,
without any relay R being interpolated, the current passing through the line wire L,
the junction Z, the pillar K, the armature a¹, the set screw ', the spring c, the
binding screws 1 and G', the wire P, the conductor P, the metallic piece i, (resting
upon the armature a² but insulated therefrom), the contact point e, the block el, the
binding screw VII and G', the junction Z³, the wire j, the junction Z*, and thence
to earth at E.
When the telegraphing contact T1, T2, is closed, the electro-magnet M is actuated by
the local battery B, the current passing through the spiral spring X (or the block K
in Figures 2 and 3), the key H, the plug S (Figures 1 and 2), the telegraphing
contact T, T, the binding screws IV and G, the junction Z and Z, so that the
electro-magnet M attracts its armature a² which has a very short stroke, and the
other end of which then presses against the contact point, whereby the connec-
tions hitherto existing between the circuit and the earth by means of the contact i, e,
is broken, while the circuit from the line battery B₁ and the wire L is established,
the current passing through the junction Z, the binding screws G and VI, the
pillar K, the armature, the screw and the pillar f', the binding screws V and G³,
the junction Z2, the line wire L, and returning through earth E, the junction
and the binding screws G2 and II.
After the telegraphing contacts T1, T2, are opened, the armature a² falls back
with its insulated contact piece i upon the set screw e, and thereby establishes
connection to earth through which the current passes. The normal contact R', R²,
is now closed, whereby the armature a¹ is attracted by the electro magnet O. This
attraction of the armature a¹ is retarded by suitable mechanisin and means,
influencing the action of the current, such as a further spring tension, the move-
ment of a running weight connected to the armature, the interposition of the
resistance U in the local circuit connected, with the electro maguet O, or the like,
so that the armature may not fully follow, in consequence of the rapid making and
breaking of the normal contact R, R, or the attracting impulses of the electro
magnet O, so that the contact of the armature al against the set screw c¹ remains,
that is to say the discharge current is continuously connected to earth, the connec-
tion being only broken as above described when transmitting a sign and hence
making the contact a², f.
If the contact R1, R2, remains a little longer in its closed position, the armature a
is fully attracted by the electro-magnet O, whereby the contact of the armature a
with the screw c¹ is opened, the connection to earth is broken, and the relay R is
inserted.
It is therefore left at the operation of the operator whether he allows this relay
to be inserted or not after each elementary sign, whole letter, or full word. As, in
practice, the insertion of a relay after each full word fully suffices to prevent the
possibility of a break, the operator need not look, after each sign, to the complete
closure of the normal contact R1, R2, but this closure may be allowed with full
security after each complete word.
When telegraphing by means of alternate currents (Figures 1 and 4) the plug S
is withdrawn from the key H and all the binding screws G are connected with the
binding screws W. Another battery B2 is connected, as shewn in the general view,
with the battery B'. When the key H is at rest both the electro magnets O and M

page_text: are actuated, as being parallel-the current passes, as regards the electro magnet ()
through the spiral spring X, the key H, the contacts R', R, the junction 77, the
resistance U, round the electro magnet O, to the junction Z', and the negative pole
of the battery B, and as regards the electro magnet M, through the spiral spring X,
the key H, the normal contact R1, R2, the junction 77, the binding screws III
and W, and the junction Z, Z. As the sign is transmitted the normal con-
tact R', R, is first opened, whereupon the armature a¹ (as above explained) presses
against the set screw c', raises the spring c, and strikes the set screw G.
same time the electro magnet M releases its armature a, which having a short
stroke allows the contact piece i to fall upon the screw e.
At the
When operating with alternate currents only, the insulated contact is not
required, the armature a falling directly upon the contact e, the wire P¹ and the
binding screws W8 and V111 being likewise dispensed with.
When the telegraphic contact T1, T2, is closed, the armature a² being already in
contact with the contact point e, a current is sent into the circuit, passing from the
battery B through the junction Z, the binding screw W and I, the spring, the
set screw e, the armature a', the pillar K and the junction Z, to the line wire L,
and back through earth at E, junction Z, wire, junction Z, binding screws Wo
VI, VIII, WS, conducting wire P, insulated contact piece i, set screw e, pillar e¹,
binding screw VII, W, IV, telegraph pieces T', T2, wire V, and binding
Screws W, II. Telegraphic contacts T, T, being now opened the apparatus
remains inoperative, but the closure of the normal contacts R', R², causes a current
to be sent in a contrary direction to that of the former one, from the battery B²
into the circuit, whilst in consequence of the above described limitation of the
mobility of the armature a' or of the attractive capability of the electro magnet O,
the contact between the armature a' and the set screw c is not immediately broken
by the closure of the normal contacts R', R², but the armature a² is momentarily
attracted by the magnet M. and brought against the contact point. A current is
thus generated in an opposite direction by the positive pole of the battery B, this
current passing through the wire V, the binding screws W, and V, the pillar f',
contact point, armature a², pillar K, binding screws VI, and W, junctions Z, Z^,
to earth E, and back through the line wire L, junction Z, pillar K', armature a',
set screw c', spring, binding screws I and W, junction Z, to the negative pole of
the battery B.
If further work is carried on, this negative current is immediately broken owing
to the separation of the normal contacts R1, R2, and the resulting opening of the
contact between the armature a² and the contact point whilst the contact between
the armaturea and the set screw el is only broken, as above described, when the
closure of the contact R, R, is of somewhat longer duration.
When operating by means of alternate currents, an absolutely secure closure of
the normal contact R, R, should be effected after each elementary sign. When
the apparatus remains without working for any length of time, the current from the
local battery can be broken by withdrawing the plug, whilst the break occurring at
the same time between the circuit, the relay, and the earth, in consequence of the
movement of the armature a', can be remedied by a suitable insertion of plugs
between the circuit or line wire L and the pillar d
The receipt of signs is effected in a similar manner in both cases, through the
circuit L, junction Z, pillar K, armature a¹, set screw d, pillar ª, relay R,
junction and earth E.
Having now particularly described and ascertained the nature of the said inven-
tion and the manner in which the same is to be performed, I declare that what I
claim is
An apparatus or arrangement for telegraphing either with direct currents and
earth connections or with alternate currents, consisting of a key or lever H with
normal and telegraphing contact points R', and T', which are either electrically
connected together or separate from one another, and the contact of which with the

page_text: contact pieces R², or T2, (or the separation therefrom), successively or simul-
taneously actuates or puts out of action two electro-magnets M and O, the
armature a² of the former having a short stroke, whilst the armature a' of the latter
has a long stroke for the purpose of making and breaking contact at different times
by the common action of the rapid movements of the armature a² and the retarded
movements of the armature a', whereby at each sign either a circuit from the
apparatus to earth is formed, or a current having an opposite direction to that of
the sign current, is sent into the circuit, substantially as set forth and illustrated in
the accompanying drawings.
Love of Waham 1901
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Applicant.