IMPROVEMENTS IN ELECTRIC TELEGRAPH APPARATUS
Year: 1867

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the
Office of the Commissioners of Patents, with his Petition, on the
17th October 1867.-A communication from abroad by C. H. Pond, of
Oberlin, Ohio, United States of America.
I, WILLIAM ROBERT LAKE, of the "International Patent Office," No. 8,
Southampton Buildings, Chancery Lane, in the County of Middlesex, Con-
sulting Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN ELECTRIC TELEGRAPH APPARATUS," a communication, to be
as follows:-
My improvements are designed to obviate the difficulties in practical
telegraphy arising from the changes or variations of the electric current in
damp or wet weather, or when the lines are not in perfect insulation, which
greatly impedes the transaction of business. For instance, if the current one
moment becomes strong residual magnetism is strong in proportion, and there
must be a corresponding spring power to repel the armature from the poles
of the electro-magnet the instant the current is broken, or the residual
magnetism developed by the strong current will hold the armature to the
poles, and there will be no stroke. Should the next impulse of the current
be exceedingly weak residual magnetism will also be exceedingly weak, and
there must be a loose tension spring or the magnetism developed by the weak
current will not be sufficient to overcome the spring resistance, and in this
case also there will be no stroke. These changes are constantly taking place.
when the line and weather are not in a favorable condition for working, and.

page_text: the utmost skill is required to
Frequently these variations are
ments now in use cannot be
obstructed.
keep the instruments properly adjusted.
so violent and rapid that the relay instru-
kept adjusted, and business is thereby
With my improved self-adjusting instrument these difficulties are obviated,
and business can be transacted at all times regardless of weather or imperfect
insulation and at a more rapid rate. The said instrument is provided with
suitable electro-magnets and a vibrating armature lever whose backward
stroke is regulated by an adjusting screw. A vertical post is fixed upon the
stand or foot of the instrument for holding the local connections, and leading
posts are provided for the electro-magnet connections. A jointed forked arm
is connected to a frame on the top of the vertical post, and the friction of this
aim is graduated by a spring whose pressure is regulated by a check nut. A
screw is provided to vary the play of the armature lever in the said forked
arm, and also a screw to increase or diminish the tension of the resistance
springs of the said lever which are attached to a foot or stem; binding posts
for the local connections are attached to the stand. A contact screw is sup-
ported upon a post between the magnets; the local circuit is completed
between one of the binding posts, through the vertical post and frame, with the
jointed forked arm and screw point. Another binding post is connected with
the armature lever; when. this lever 'is in contact with the. said screw point
the local connection is complete; a second or double local connection is
employed with the second binding post. When the instrument is in operation
a current passes through the electro-magnets which attract the armature
lever; the latter brings its point against the screw point, and thus closes the
local circuit. The local current now passes in at the second binding post, up
the armature lever, over its point to the screw point, thence over the jointed
forked arm down a wire connection to the frame and vertical post and passes
out at the first binding post. When the main circuit is broken and the
magnets cease to act the resistance spring repels the armature lever and
separates its point from the screw, thereby breaking the local circuit. When
a beavy current passes over the magnets the magnetism is stronger, and will
more forcibly attract the armature lever which will overcome the spring and
bring the point of the said lever and the screw point in contact, thereby
closing the local circuit, and will then move the jointed forked arm along with
it until the lever point strikes a second spring near the resistance spring and
is thereby stopped. The local circuit can now pass over the contact point
and screw point or over another point and spring connection, which is the
same as that of the jointed forked arm, but is used only when strong currents

page_text: pass through the magnets, as the armature spring is sufficient to repel the
armature lever when ordinary currents are employed. The fork on the jointed
arm having a light tension will bound off and break the local connection
between the first contact point and screw point under the influence of a heavy
current; hence the double connection is used and is secured by a second
resistance spring and point of the lever.
When the main current is not sufficient to overcome the first resistance
spring it is not sufficient to cause the jointed fork to rebound, and when it is
strong enough to overcome the said spring the local connection is made by the
second contact point and spring which have sufficient tension to stop the
forward movement of the armature lever; thus one or both connections of
the local circuit will always be in adjustment for any circuit. The space in
the fork of the jointed arm in which the armature lever acts being small and
carried along with the said lever, the latter has only a slight distance to travel
before closing the local circuit, but the fork being hinged the armature
lever is permitted to move forward until the spring power offered by the
contact points is sufficient to overcome the force of the magnet and stop it,
and hence the instant the said magnets cease acting wholly or partially the
spring power will repel the lever proportionately, so that any part of the main
current can be controlled or broken. The resistance spring will always be
influenced by the loss of power of the magnets, and having but little play in
the hinged fork the local circuit is broken the same as though the entire
main current ceased acting. If the connection point for the local circuit
were permanent instead of being hinged the armature lever could not benefit
by the various spring tensions, but would be limited to a uniform resistance,
as in the common instruments now in use. Instead of stopping the forward
movement of the armature lever with a fixed point, as in common relays, it is
stopped, as described, by spring power, which is always equal to the power of
the electric current.