IMPROVEMENTS IN ELECTRO-MAGNETIC TELEGRAPHS
Year: 1862

page_text: LETTERS PATENT to Henry Wilde, of the City of Manchester, Engineer,
for the Invention of "IMPROVEMENTS IN ELECTRO-MAGNETIC TELEGRAPHS."
Sealed the 16th December 1862, and dated the 22nd October 1862.
PROVISIONAL SPECIFICATION left by the said Henry Wilde at the
Office of the Commissioners of Patents, with his Petition, on the
22nd October 1862.
I, HENRY WILDE, of the City of Manchester, Engineer, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN ELECTRO-MAGNETIC
TELEGRAPHS," to be as follows:-
My Invention consists in improvements in the transmitting instruments
described in the Specification of Letters Patent granted to me on the Eighth
day of April and on the Tenth day of August, One thousand eight hundred
and sixty-one, and numbered 858 and 1994 respectively. In the Specifications
of these Patents transmitting instruments are shewn and described where the
armature of a magneto-electric machine is mechanically geared with a radial
arm which travels beneath a series of finger keys, any one of which being
depressed arrests the motion of the radial arm and also the motion of the
armature with which it is mechanically connected.

page_text: In the present improvement the axis on which the armature or armatures
are fixed has two different motions given to it simultaneously in circular
and lateral direction, which two motions are produced by two different forces
acting simultaneously in different directions. The magneto-electric machine
which I prefer to use in this arrangement is the one described under the head
of the third improvement of the above-mentioned Patent, No. 1994. Two
rectangular plates of soft iron, forming the armatures, are fixed to an axis at
right angles to each other, and are made to revolve before the coiled extre-
mities of two horseshoe or rectilinear permanent magnets by means of a
pulley or wheel. The axis which carries the armatures is allowed to move
freely on its bearings in a lateral direction parallel with itself, so that when a
circular motion is given to the axis the armatures, in moving past the poles of
the magnets, are alternately attracted by them in opposite directions, which
produces a reciprocating motion of the axis endways simultaneously with its
rotory motion. This reciprocating motion of the axis is communicated to a
lever by placing one end of it between two smooth, collars fixed to the axis.
Near the other
of this lever a pin is inserted, which, by the vibra-
tions of the 'lever an intermittent rotary motion of the radial arm
beneath the finger, keys, and also of the index finger fixed to the same axis,
by means of the combination of wheelwork described under the head of the
first improvement of the before-mentioned Patent, No. 858, only in this case
the moving parts of the instrument are made larger and stronger. The
bottoms of the teeth of the star wheels limit the vibrations of the lever and
armatures, which are only allowed to move through a very small space, so
that the full effect of the magnetic induction may be utilised. The lever is
placed in connection with one extremity of the coils of the magnetro-electric
machine, and the extreme end of the said lever adjoining the driving pin is
made to vibrate between the points of two contact screws, both of which are
connected with the line wire and insulated from the other parts of the instru-
ment. The distance of the screws is so regulated that when the lever is in
contact with either of them the pin which drives round the wheels and radial
arm is also at the bottom of the tooth of either one star wheel or the other;
but when the radial arm is arrested by the depression of a finger key the lever
is prevented from touching the contact screw on the side to which it moves, in
consequence of the driving pin not being able to get to the bottom of the
tooth of the star wheel, though at the same time the lever is at liberty to
make and break contact with the opposite contact screw. The action of the
apparatus when in operation is as follows:-The revolution of the armatures
causes a number of equal and alternately inverted currents of electricity to be

page_text: generated in the coils surrounding the magnets, which are transmitted through
the line wire by means of the lever vibrating by the action of the permanent
magnets between and making contact with the two screws above mentioned;
and since the currents of electricity produced move alternately in opposite
directions, and one current corresponds with one vibration of the lever, one of
the contact screws will receive all the currents in one direction, and the other
contact screw will receive all the currents from the opposite direction, and so
long as a key is not pressed down the inverted currents act uninterruptedly
on the indicating instruments placed in the telegraphic circuit; but when a
finger key is pressed down the resistance offered to the radial arm overcomes
the attractive force of the permanent magnets and arrests the reciprocating
motion of the armatures and also that of the lever, which being at liberty to
touch but one of the contact screws on one side only, the currents are
transmitted along the line wire in one direction, and from the well-known
construction of the indicating instruments, which require inverted currents to
actuate them, the currents transmitted along the line wire in one direction
only will produce no effect on them; and when the index finger of the trans-
mitting instrument is stopped opposite a letter by the depression of a finger
key, the index finger of the receiving instrument at the distant station will stop
at the corresponding letter also. The currents from a number of magneto-
electric machines geared together may be regulated by the reciprocating
motion of any one of the armatures of such machines in the manner described
by connecting up all the wires in a suitable manner with the vibrating
lever.