Improvements in Telegraphic Apparatus.
Year: 1885

page_text: Improvements in Telegraphic Apparatus.
I, PATRICK BERNARD DELANY, of New York City, in the State of New York,
U.S.A., Electrical Engineer, do hereby declare the nature of my invention 'for
IMPROVEMENTS IN TELEGRAPHIC APPARATUS and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement :-
My invention relates more especially to the system of telegraphy for which a
patent was granted to Sydney Pitt a communication from me dated Oct. 9, 1883,
No. 4787. That patent relates to a system based upon the synchronous movement
of apparatus at two connected stations. All the details necessary to the under-
standing of the present invention are fully set forth in that patent, and specific
description and illustration here are unnecessary.
With an ordinary relay the interruptions in the circuit in my synchronous
system would probably cause a singing or chattering of the relay and sounder.
Of
course the extent of this disturbance would depend more or less upon the number
of contacts connected in each independent circuit. In my present invention I
employ a condenser in connection with a relay, as is fully explained below.
In Fig. 1 I have shown two connected stations X and Y. At each station there
is a section of a circular table of contacts A and a circuit completer B. The branch
line z at each station-only one being shown-is illustrated as connected with a
7-contact. Of course each branch circuit may be connected with any desired
number of contacts, as fully described in my patent. At each station the branch
line is connected with the armature c of a transmitting magnet C included in a
local circuit with the transmitting key K. When the key is depressed to close
the transmitting circuit the armature c is attracted and the main battery M B is
put to line. Normally, however, the armature lever c is drawn against its back
contact c2 so that the line is connected directly through the armature lever c,
contact c2, coil of relay R to earth. When an operator is telegraphing from one
station to another, whenever the sending operator's key is depressed the main
battery is sent to line, and whenever his key is raised his line is put to ground

page_text: through his relay R. The receiving operator at the distant station may therefore
at any time "break" the sending operator by depressing his key.
The details of my improved relay are shown in Fig. 2. It may be a double pole
or double coil relay, though not preferably so.
Referring to the double-coil relay shown in Fig. 2, the coils are wound with two
wires side by side, one of which is directly connected with the branch circuit z, and
the other with a wire w connected with the poles of the condenser Cd. When a
current from the negative pole of the transmitting battery at the distant station
enters the relay by the line marked, the polarity of the poles of the relay
magnet will be as lettered, and will correspond with the poles of the permanent
magnet V. The permanent magnet is preferably arranged either above or below
the relay coils and attached directly thereto. Its poles N S are arranged in
proximity to the ends of the coils, like poles of the permanent magnet and relay
being adjacent to each other. The purpose of this arrangement is to increase the
lines of force in the field of the relay magnet and prevent its rapid demagnetization;
in other words, to cause the relay magnet to act lazily in releasing its armature.
With a relay so constructed, the fact that a number of distinct electrical impulses
are sent through it, while the operator at the transmitting station holds down his
key to make a given signal, will not, with the proper adjustment of the armature
spring, be apparent at the receiving station.
The individual impulses which are received in the formation of any one signal
each induces a current in the wire w which charges the condenser; and in the
formation of any unitary signal during the brief interval between the impulses,
when there is no main line current, the condenser is discharged through the
wire w and the armature of the relay is prevented from leaving its front stop.
There will therefore be no chattering of the sounder unless the relay armature
makes and breaks contact with its back post. The relay R may actuate the local
sounder directly in the ordinary way, but, if preferred, an intermediate relay T
placed between the main line relay and the sounder may be used. Any form of
intermediate relay and any form of sounder may be employed in connection with
my improved relay.
In Fig. 3 the condenser is included in a shunt z¹ around the relay, and the
operation is the same as described in connection with Fig. 1.
I am aware that a main line relay having a condenser in a shunt thrown around
it is old, and I do not therefore claim such subject-matter broadly. I am not aware
that such a relay has ever been used in connection with a system of telegraphy
in which each unitary signal is made up of a number of independent impulses,
and I am not aware that such a relay has ever been used in connection with a
permanent magnet, as above described.
In the arrangement shown in Fig. 1, as before stated, the receiving operator may
readily "break" the sender whenever he chooses. This is a very important and
desirable feature and one not generally found in systems of telegraphy similar to
my synchronous system.
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. A main line having a table of contacts and a rotating circuit-completer which
traverses the table at each end of the line, whereby each signal transmitted is
formed of a series or group of momentary impulses, in combination with a relay,
and a condenser or source of electric energy from which a current is discharged to
hold the relay armature during the brief interval between the successive impulses
of electricity composing a given signal.
2. The combination of a relay whose coils are wound with two wires, the main
line circuit connected with one of said wires, and a condenser connected in
permanently closed circuit between the terminals of the other of said wires.

page_text: 3. The combination of a relay magnet and a permanent magnet arranged in close
proximity thereto, the two magnets having their like poles arranged adjacent to
each other (when the relay is energized) for the purpose set forth.
4. The combination of the relay magnet, its armature, the permanent magnet
arranged in proximity thereto, said magnets having their like poles adjacent to
each other (when the relay is energized), the main line, and the condenser, for the
purpose set forth.