IM- PROVEMENTS IN ELECTRIC TELEGRAPH SENDING APPARATUS
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by John Imray at the Office of the
Commissioners of Patents, with his Petition, on the 6th March.
1874. A communication from abroad by C. Lemon, of Wellington,.
New Zealand.
I, JOHN IMRAY, of No. 20, Southampton Buildings, in the County of
Middlesex, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN ELECTRIC TELEGRAPH SENDING APPARATUS," to be as follows:-
:-
This Invention relates to means and apparatus for sending telegraphic
messages automatically by transmitting through a line wire electrical
currents of longer or shorter duration with longer or shorter intervals, so
as to produce on a receiving instrument at a distant station combinations
of dots and dashes or other short and long indications forming pre-
determined symbols according to the Morse or other like code. For this
purpose a strip of paper is punched by any known method with holes or
slots through it of less or greater length separated by longer or shorter
intervals, according to the succession and combination of dots, dashes,
and intervals, which it is desired to produce at the receiving station.
This strip of paper is led by guide rollers over a conducting roller which is

page_text: caused by clockwork to revolve at a velocity regulated to suit the practical
speed of transmission and reception of the signals, and in its course
passes between a caoutchouc or other yielding roller and an adjustable
rubber which act as a brake so as to give the paper strip a certain degree
of tension. The conducting roller has a groove round it in a position
corresponding to the line of holes or slots in the paper strip as it passes
over it. A conducting disc is mounted on the arm of a lever pressed by
a spring, and so arranged that the edge of the disc is pressed into the
groove of the conducting roller. Another arm of the lever is provided
with a contact spring near which is placed a conductor. The portion of
the apparatus containing the conducting and guide rollers is connected
with one pole of a battery or other source of electric power, the other
pole of which is connected to earth. The lever carrying the conducting
disc is connected to the line wire, and the conductor above referred to is
connected to the pole of a battery of small power opposite to that pole to
which the instrument itself is connected. As the paper strip is carried
by the conducting roller between it and the conducting disc it interrupts
electrical connection between the roller and the disc, except when a hole
or slot in the paper is presented, in which case the edge of the disc
passing through such hole or slot makes contact with the roller, whereby
an electrical current is transmitted from the battery into the line wire,
the duration of such current being proportioned to the length of the
_hole or slot in the paper. At the termination of the hole or slot the disc
is raised by the paper out of contact, and the movement thus imparted
to the arm of the lever on which the disc is mounted causes its other
arm to make contact with the conductor, whereby an opposite current of
small power is transmitted into the line, so as to discharge the same by
neutralising the residuary electricity left in it.
When by the onward movement of the paper another hole or slot is
presented to the disc it again makes contact for the passage of an
operating current, at the same time breaking contact with the
neutralising current. The successive short or long currents with the.
intervals between them, thus determined by the arrangement of holes,
slots, and intervening spaces in the paper, are applied at the distant -
station by means of a Morse or other known receiving instrument of like
kind to mark a travelling strip of paper with dots and dashes, or other-
wise to form symbols distinguished by combinations of long and short.
indications

page_text: When the apparatus described above is employed to transmit currents
in comparatively slow succession or through a short line, the alternating
contact for discharging the line may be dispensed with.
In order to maintain the efficiency of the contact surfaces the con-
ducting roller is preferably made with that portion of its periphery in
which the groove is cut of platinum, and the conducting disc is also
made with an edge of the same metal, or it may be a thin disc of
platinum clamped between side cheeks of brass or other metal.