PROVEMENTS IN ELECTRIC TELEGRAPHS.
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Edward Alfred Cowper at the Office
of the Commissioners of Patents on the 26th February 1879.
EDWARD ALFRED COWPER, of No. 6, Great George Street, Westminster.
PROVEMENTS IN ELECTRIC TELEGRAPHS.'
"
ss
IM-
My Invention relates to the method of transmitting telegraphic signals for which
Letters Patent were granted to me on the 15th June 1878, No. 2385.
According to this method the movements of a pen or style at the sending station
were caused to introduce varying resistances into two electric circuits connected
with the receiving station, so that the varying currents in acting upon two electro
magnets at the latter station caused these to impart movements in two directions at
an angle to each other to the receiving pen or style, whereby this was made to
reproduce the writing or characters produced by the sending pen.
In the arrange-
nient described in the Specification to the said Patent the receiving pen was
connected by a system of threads or wires to two horizontal soft iron cores or bars,
mounted on axes within fixed coils through which the varying currents were passed
and situated between the poles of fixed magnets, or the varying currents were
passed through the coils of fixed electro magnets, so that the varying movements of
the said cores or bars were imparted through the threads to the pen.
According to one of my present improvements I employ in place of this arrange-
ment a single moveable soft iron bar, tube, or needle, which is connected directly to,
and is in line with or parallel to the pen or style, being suspended between two
fixed electro-magnets or two sets of such magnets situated at a right or other angle
to each other, through the coils of which electromagnets the varying currents of
the two circuits are made to pass. The needle being connected to two springs
acting upon it in opposite directions to those in which the two sets of magnets act
upon it, it will be seen that varying currents passing through the one magnet or
set of magnets will produce varying movements in the one direction in the needle,
while the varying currents passed through the other magnet or set of magnets will
produce varying motions in the other direction at a right or other angle to the first,
and these motions being imparted directly to the pen or style will cause this to
reproduce the characters written by the sending pen. The suspension of the needle
so as to enable it to move in every direction may either be effected by resting it on
a point or on a universal joint to any part of its length, or it may be suspended
from a spring or from a flexible thread or wire. It may be either rigidly fixed to
the pen or style, or the latter may be supported independently of the needle, and be

page_text: so connected thereto that the pen is caused to reproduce the motions of the needle
in a more or less magnified manner. In order to render the cores of the fixed
electro magnets as sensitive as possible to slight variations in the current I make
them of bundles of fine wires or thin plates in a manner well known.
According to another improvement which has for its object to raise the pen from
the paper when it ceases to write, and which is applicable either to the above
described arrangement or to that described in the Specification of my previous
Patent, I apply to the pen or style a spring acted on by an electro magnet or
magnets through the coils of which the currents of the two circuits are made to pass,
so that on the passing of such currents the pen is allowed to descend by the action
of the electro magnet in opposition to the spring so as to come in contact with the
paper strip, while when the currents are caused to cease by raising the sending pen
on the completion of the word or character transmitted the spring raises the pen
out of contact with the paper, thereby causing each word or character transmitted
to be written separate from the other or others adjoining it as in ordinary writing.
In place of raising and lowering the pen for the above described purpose the surface
over which the paper strip travels may be made to rise and fall slightly together
with the paper by the action of the electro magnet and spring.
I have described my method of transmitting telegraphic signals, as being worked
by two separate electrical circuits, but it will be evident that by the application of
the well known "duplex" system a single circuit may be used for the purpose, also
that instead of using the currents from the line wire or wires direct, these may be
made to operate relays at the receiving instrument in a well known manner.
.