IMPROVEMENTS IN RECEIVING INSTRUMENTS FOR ELECTRIC TELEGRAPHS
Year: 1884

page_text: I, WILLIAM PHILLIPS THOMPSON Fel. Inst. P.A. of No. 6 Lord Street Liverpool
in the County of Lancaster and of 323 High Holborn in the County of Middlesex,
Civil Engineer do hereby declare the nature of the said Invention for IMPROVEMENTS
IN RECEIVING INSTRUMENTS FOR ELECTRIC TELEGRAPHS and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
°
The object of this Invention is to provide mechanical means for vibrating the
tongue, lever, style or other movable portion of a telegraphic receiving instrument
by mechanical power, which is adapted to be controlled by the action of a feeble
electric current upon an electro-magnet armature or needle, or by an alternate
increment or decrement in the strength of a constant current.
The Invention is especially designed for use upon long circuits or upon submarine
lines, in which the electric currents are necessarily feeble and the electro-magnetic
force available to operate the receiving instrument is consequently very small.
The essential features of the Invention are as follows:
A movable tongue or lever is hinged or pivoted to a fixed support and is-adapted
to vibrate between adjustable or stationary stops or limiting screws, in the same
manner as the armature lever or tongue of an ordinary telegraph relay. A marking
or recording device may be attached in the ordinary manner directly to this tongue
or lever, but it is preferable to employ it for the purpose of opening and closing
a secondary or local circuit by means of which any suitable recording or secondary
device may be operated in a manner well understood. This tongue or lever is
moved to-and-fro by a piston which is actuated by a hydraulic column enclosed
in a tube and extending to another or larger piston, the tube in which this
hydraulic column is enclosed being fitted with an air chamber for the purpose of
rendering the movement more steady. The last named piston is caused to move
in one direction by motion communicated from a constint motor by an endless
travelling belt.or band, and in the other by a spring. The motion of the belt
however is only communicated to the piston during the reception of a signal, that
is to say while the electro-magnet is active. This result is accomplished by causing
the moving belt to traverse a system of movable pulleys, and also a pulley fixed
on the axis of a suitable train of wheel-work, the last and most rapidly moving
axis of which carries a friction drum or brake-wheel. The brake is adapted to
press against the periphery of this wheel and is attached to the armature or
armature lever of the electro-magnet. As the brake is made to act upon the last

page_text: and most rapid moving wheel of the train, which train it is to be understood is
kept in constant motion in one direction by the endless belt and its actuating
motor, it will be understood that it acts with great mechanical rapidity, so that the
least pressure exerted by the attractive force of the electro-magnet will sensibly
check the foresaid motion of the wheel-work, and will tend to tighten the belt
upon one side and to slacken it upon the other. These two portions of the belt
pass respectively over two pulleys which have their axes attached to the opposite
ends of a second belt or chain passing over a pulley to whose axis is affixed & pinion
working into a rack upon the rod of the larger piston hereinbefore described.
Suitable means are provided for adjusting the normal tension of the driving belt,
and also for suitably adjusting the retractile force of the spring by which the
armature is withdrawn from the electro-magnet, and consequently the brake-shoe
from the drum on which it operates.
In the accompanying Drawing, Figure 1 represents the essential portions of my
improved apparatus, and Figure 2 is a detailed view of a portion of the same.
Referring to the Drawing, A is the actuating electro-magnetic coil which is
represented in the form of an ordinary electro-magnet, consisting of a soft-iron
core having helices of insulated wire, the attractive force of the cores being
exerted upon the soft-iron armature a. Any other form of electro-magnetic
apparatus adapted to the conditions of different lines or different systems of
telegraphy may be used, such as a polarized electro-magnet or a movable coil
vibrating in a constant magnetic field, or other equivalent devices for producing
mechanical motion by the energy of an electric current.
L
The movable lever B, is pivoted at b to a stationary support and carries the
'armature a at or near its end. The drum or friction wheel C is mounted upon an
axis c in such a position that its periphery is in the vicinity of the lever B.
A friction brake or shoe D is affixed to the lever B in a position as shown so that
the slightest movement of the armature a toward the poles of the electro-magnet A
will bring it into frictional contact with the periphery of the drum C. Upon the
axis c of the drum C is fixed' an endless spiral thread or worm E of considerable
pitch which is engaged by a toothed wheel F. The latter being driven by a grooved
pulley on the same axis. The last named pulley is caused to revolve constantly
in one direction by an endless belt J which is also conducted over and around
a system of pulleys which will shortly be described. K is a pulley mounted upon
an axis k turning in stationary bearings or supports over which passes a belt cord
or chain L L to the extremities of which are attached the axes of two movable
pulleys G and I.. Another pulley H is mounted upon a sliding bar h, movable
to-and-fro in the direction of its length. by means of a set screw h' or other
equivalent device. The belt J is driven by a constant motor not shown in the
Drawings and moves continuously at a uniform rate of speed in the direction
indicated by the arrows, passing first over the pulley G and thence once over the
pulley and thence over pulley H which serves to adjust the tension of the belt
throughout the whole system as required, and thence a second time around the
⚫ pulley f, and thence over the pulley I after which it returns again to the motor.
Upon the axis k of the pulley K is a toothed wheel or pinion M which engages
with a rack m upon a piston rod or stem p of a piston P moving in a cylinder O.
N is a spiral spring one end of which is secured by a clip at n and the other to the
axisk of the pulley K. R is a second cylinder, similar to the cylinder O, but
preferably of lesser diameter, within which moves the piston r. The tube Q
establishes a communication between the lower portion of the cylinder O and R
and this is filled with a suitable liquid forining a hydraulic column whereby motion
communicated to the piston P will be transmitted to the piston r.
This tube may
be fitted with a suitable cock-stop S for preventing such transmission when desired.
T is a closed air chamber communicating internally with the tube by a passage.
which may be closed at will by means of a stop-cock 8. The piston rod or stem r¹
is pivoted to a lever or tongue V which is capable of vibrating to-and-fro between
stops or limiting screws W and W', and may thus be made to alternately open and

page_text: close the circuit of a local battery X containing a telegraphic apparatus Y of any
desired construction.
The operation of the apparatus is as follows: The electro-magnetic coil A is
included in the circuit of the line coming from the transmitting station. When no
current is traversing the line the armature is drawn away from the magnet by the
retractile force of the spring 6', and hence the shoe or brake D is not in contact
with the periphery of the drum G, and hence the latter revolves freely at a high
rate of speed being driven by the belt J, as it passes over the pulley f.
So long as the drum C is free to revolve the difference in the tension of the
belt J at the points where it passes over the pulleys G and I respectively is not
enough to overcome the resistance of the spring N so as to turn the pulley K. If
however the shoe D touches the periphery of the drum C a considerable mechanical
resistance is offered thereby to the movement of the belt J, the effect of which is
to tighten it at J¹ and cause it to become more slack at J. The immediate result
of this is to alter the relative position of the pulleys G and I, thus causing the
belt or chain L L to move a short distance in the direction indicated by the arrows
until the equilibrium is restored, after which they will remain in that position
until the brake-shoe D is withdrawn from the drum C. This movement of the
belt or chain L causes the pulley K and pinion M to revolve in opposition to the
stress of the spring N, thus forcing down the piston P and exerting a corresponding
pressure within the tube Q, tending to raise the piston R, thereby bringing the
lever V into contact with the stop W₁ and producing a signal either directly or
through the intermediate action of the battery so long as a current traverses the
actuating electro-magnetic coil A.
When the current through the coil A ceases the brake D is withdrawn from the
drum C and the spring N restores the entire apparatus at its normal position.
The function of the air-chamber T is to act as a spring or cushion for the
hydraulic column and thus prevent tremulous or uncertain contacts being made by
the lever V.
I claim as my Invention:
1. A telegraphic receiving instrument in which the operating tongue or lever is
moved in one direction by mechanical force derived from a constant motor and
in the opposite direction by a spring, and an electro-magnet for controlling the
action of said motor upon said movable portion of the instrument.
2. The combination of a movable tongue or lever moved in one direction by the
movement of a constant motor and in the other direction by a spring, a friction
brake controlled by an electro-magnet, and a system of pulleys traversed by an
endless belt, whereby the action of the constant motor upon the movable portion
of the apparatus is determined.
3. The combination of a tongue or lever moved in one direction by the
movement of a constant motor and in the opposite direction by a spring, and
a hydraulic column for transmitting the said movement to the operative portion of
the apparatus.