Improvements in Electrical Signalling Apparatus.
Year: 1891

page_text: COMPLETE SPECIFICATION.
[Communicated from abroad by SAMUEL JOSEPH BURRELL, of 54, Broad Street,
New York, United States of America, Contractor.]
Improvements in Electrical Signalling Apparatus.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
This invention relates to that class of electrical devices primarily designed, and
used for establishing, by the manipulation or operation of suitable mechanism at
one station, electrical communication between such station and any other along the
line of a given circuit upon which both are located. Such apparatus is frequently
used in telephone systems, where a number of subscribers are connected with the
same line to call up one subscriber without ringing the bells of the others on that
linc.
It may also be used in signalling systems in connection with railroad
business, as for the despatching of trains or the giving of other orders, and in
general to call up any one of a number of stations on a given line without
disturbing or operating the instruments at any of the others.
At a central or given station on a signalling circuit or line is a main battery and
a transmitting key or a number of automatic transmitters, each adapted to produce
a given number of makes and breaks of unequal length. The usual receiving
instruments, relays, bells and the like though used, need no specific description or
illustration.
At each of a given number of stations along such line is a plate or bar provided
with notches of different character to correspond with the contact surfaces of one
of the automatic transmitters at the main station.
This plate is capable of being moved past a given point at a predetermined rate,
and at such point is à vibrating armature which is moved in response to whichever
transmitter may be operating, like the lever of a sounder, making dots and dashes.
The essential conditions of operation are that the first impulse of current of a
series comprising a call sent over the line will start in motion all the notched
plates, and that such impulses follow one another at certain definite intervals of
time corresponding to the rate of movement of said plates.
The plates are differently notclied or formed in an equivalent manner, so that
unless the exact signal be transmitted for which a given plate is designed, the
vibrating armature instead of encountering the plate or some projection thereon
will pass through a notch therein and close a local circuit that instantly throws the
plate back to its original position. Only that plate, therefore, will complete its
movement which corresponds to the signal or call sent, and this complete movement
is utilized to sound an alarm, send a return signal or to effect any other desired
result, as hereinafter explained.
In the accompanying drawing:
Fig. 1 is a side elevation of the local signalling apparatus embodying my
invention.
Fig. 2 is a similar view from a direction at right angles to the first.
Fig. 3 is a plan view of the same.
Figs. 4 and 5 are views of details of the mechanism.
Fig. 6 is a diagram of circuits with the apparatus connected therewith.
As the construction of the apparatus at the stations differs only in respect to the
particular form of the parts designed to send and receive signals, according to the

page_text: special signal to be sent or received, only one has been shown and will be hereinafter
described.
The specific arrangement and manner of associating the operative parts of the
apparatus is largely immaterial, and that shown is selected mainly for convenience
of illustration.
A. is an electro-magnet in the main circuit over which signals are to be sent, or
preferably, as shown in Fig. 6, in a local circuit controlled by a relay B, in the
main circuit and normally closed.
One leg or pole of this magnet is or may be without a coil, and to it is hinged an
armature A provided with a non-magnetic extension A" extending up through a
slot in the base B. The armature is retracted from the wound pole by means of
an adjustable spring B".
In suitable supports C on the base B' is mounted a horizontal shaft C¹, upon
which is fixed, so as to turn in the path of the armature extension A", a segmental
disc oi curved plate or bar C
A pinion D fixed to this shaft is in gear with a curved rack or segmental gear D¹
carried at the end of a rigid lever D₁, pivoted at its opposite end to a standard E
on the base B. Said lever is acted upon by a spring, as for example, a coiled
adjustable spring E' connected therewith and to a fixed arm or standard E", which
tends to lift or raise said lever and through the instrumentality of the rack and
pinion to turn the shaft C' and the plate C in the direction which restores it to
normal position after a partial or complete movement thereof accompanying the
action of the signalling mechanism.
F is a second electro-magnet the coil of which is in a local circuit. This magnet
is preferably constructed like the other, and an armature lever F1 is pivoted to the
extremity of the unwound pole or leg and extends over the end of that containing
the coil.
It is desirable that this armature should have a comparatively wide range of
movement without very marked variation of power, for which purpose many forms
may be adopted. In the present instance the pole of the stationary core is conoidal
and extends up into a recess or perforation in the armature bar.
By means of a link or other flexible connection F this armature is connected
with the lever or bar D, so that if the circuit of magnet E be closed it will
operate to draw down the lever D and to turn the shaft C' and the plate C"
carried thereby, through an angle determined by the extent of movement or play of
the armature Fi
Loose on the shaft C₁ is a gear-wheel I. engaging with a pinion I¹ on a short
shaft carrying an escapement wheel I" with which engages an ordinary pendulum
escapement J. Connection between the wheel I' and the shaft C is maintained by an
arm J secured to the shaft C' and carrying a hinged pawl e that engages either with
the wheel or with a second wheel secured to the former. Thus while the
movement of the armature F¹ towards the magnet Fis imparted to the plate C
and such movement is retarded while the magnet Fis energized, the instant said
magnet is demagnetized the armature rises freely under the action of the spring,
and the plate C is carried rapidly back to its normal position.
The movements of the plate, however, under the impelling power of the magnet F
on the one hand and the spring E' on the other, are controlled by the action of the
armature extension A" and the devices associated therewith.
G is a lever pivoted to a stationary support back of the plate G" and is
connected to the armature extension A by means of a link G'. The upper and
longer arm of this lever carries a thin blade G that is designed to be thrown
forward by the movement of the lever through the notches or cut-away portions of
the plate C".
The edge of the plate C" is serrated, as shewn, or provided with projections
and notches of any kind that answer the same purpose. Some of the notches are
deeper than others, so that should the armature 'A' be drawn forward at a time

page_text: when a deep notch is presented to it, a pin a on said armature extension will pass
through said notch permitting the extension A" to strike an insulating sliding
pin H that separates two contact points in the local circuit H' of magnet F
and demagnetizes said magnet. On the contrary, if an impulse of current attracts
the armature A' at the moment of presentation of a shallow notch, the pin a strikes
the edge of the plate without passing through the notch, while a part of the
extension A" enters the notch and arrests the movement of the plate until the next
impulse is sent.
The signals may be sent by hand by means of an ordinary Morse key, but it is
desirable, in order to secure greater mechanical accuracy, to employ some form of
automatic transmitter, such as an ordinary district telegraph instrument, and to
have at the main station one of such instruments for each sub-station or subscriber.
The transmitting discs of these instruments are differently notched or spaced to
send a different number of long and short impulses in different order of succession,
and the swinging plates at the several way-stations are conformed accordingly.
One of the automatic transmitters is represented at K, in Fig. 6, but as it is an
instrument familiar to those skilled in the art, it needs no specific description.
Let it be assumed that the station at which is located the apparatus shewn in
Fig. 1, is to be called and that the appropriate call consists of three dots, dash, two
dots, three dashes, dot, dash, two dots, a dot being a short and a dash a long
impulse of current. The automatic transmitter or call box in which the signal disc
has been cut to send the above call is started in operation.
The local instrument is in the condition shewn in Fig. 1, with the circuit of
magnet A closed. The first short impulse through the relay B interrupts the
circuit of magnet A and the armature A' is retracted. The extension A" is
thereby withdrawn in one direction from engagement with the plate C and the
blade G by the movement of the lever G is withdrawn in the other direction.
The purpose of the blade G is to arrest the movement of the plate C" and not
permit it to start until the armature A' is fully retracted, and also to enter the
next notch upon the first movement of the armature forward to ensure the proper
action.
By this withdrawal of the engaging parts the plate C" is permitted to move, but
the breaking of the main current at the end of the dot causes the armature to come
forward into engagement with the next notch in the plate before the movement of
the plate has proceeded too far. In the same way the next two short impulses of
current over the line bring the extension A" in engagement with the notch 4.
The next impulse of current sent by the automatic transmitter is a long one,
hence the notch 5, which is a deep one, is carried back of the extension A., and
when the impulse terminates the said extension engages with the shallow notch 6.
In this way the segmental plate or disc is permitted to complete its movement,
the notches therein being so disposed that the extension A" is arrested each time it
is drawn forward, except in response to the last impulse, at which time a deep
notch, as 7, is presented. Through this notch the pin a passes and the extension A
pressing upon the sliding pin H breaks the circuit of magnet F, whereupon the
plate C is immediately thrown back to its starting position.
The armature F¹ and plate C", however, have completed their normal move-
ments, and this is taken advantage of in the following way :-
L is an automatic transmitter the disc L' of which when turned repeats to the
main office the signal or call of the way station at which it is located. It is turned
by the unwinding of a spring L" secured to a spindle M provided with a handle,
and its movement is retarded and controlled by an escapement M' having an
extended arm M".
A bar N is secured to the armature F¹ and is moved vertically thereby. On
this bar is a sliding lug N held down against a stop N" by a spiral spring P. This
spring also imparts to the lug a tendency to swing around away from the arm M",
but a notch is cut in this arm and when the instrument is set for use the lug N' is
turned and caused to engage with this notch.

page_text: This is the normal condition of these parts, but as soon as the armature has
completed its full range of movement, the lug N' being pushed down below the
arm M disengages the latter and permits the local transmitter L to operate and
repeat to the main station the call which has just brought it into operation. Thus
the operator at the main station will know that he has called up the proper way
station.
Attached to the spindle M is a contact arm P, and when the transmitter has
completed its signal this arm comes into contact with a stop P" and thereby
completes a local circuit O and rings a bell O₁ until the operator again winds up
the instrument and resets the lug N in engagement with the notched bar M".
Having now described the operation of the instrument when its own or proper
signal is sent, it remains to show what takes place when the signal of any other
station is sent over the line. For this purpose it is only necessary to select any
given call beginning with four dots. It is clear that the first three dots will permit
the plate C to move forward three steps, but the fourth dot will cause the pin a
to pass through the deep notch 5 to break the circuit of magnet F and return the
plate C to its normal position.
Thus, unless the right signal is passing over the line, the plate C¹ will be thrown
back two or more times and does not complete its movement.
It will be noted that the return of the plate C" occurs during the time that the
magnet A is energized, and when the pin a has passed entirely through one of the
notches in the plate. The further operation of the instrument requires the pin a to
be shifted back to the other side of the plate.
For this purpose the shaft C¹ carries an arm c¹ that encounters a stop cl on the
return of the plate and limits its movement. In this position a deep notch 8 in the
plate lies directly back of the pin a and a short impulse is then sent over the line,
which permitting the armature A' to fall back brings the pin a over to the proper
side of the plate. The circuit of magnet being thus established, the plate C" is
moved, but the termination of the impulse in the main line draws over the
extension A and causes it to engage with the first tooth or projection ahead
of the next notch in the plate. The impulse for this may be sent by a hand key or
by a single tooth, as T, on the disc of the automatic transmitter.
The liability of the instruments to improper operation is very greatly reduced by
the fact that the plates C take a fresh start after each impulse, or, in other words,
are synchronized by each impulse which causes the armature extension A" to
engage with the projections or teeth between the notches.
-
A feature to be observed in connection with these instruments is the following:-
The combinations of long and short impulses and the corresponding conformation
of the plates C must be such that the final impulse of any signal will cause all the
plates to be thrown back, so that the supplemental impulse will bring them all into
their normal starting position.
In other words, if any one signal or call is made up of thirteen long and short
impulses, so that on the completion of the thirteenth impulse the plate corresponding
to that signal will be thrown back, all the other plates must be so arranged that
this thirteenth impulse will also throw them back, whether they have been returned
once, twice or more times it matters not.
A great many combinations are possible under this requirement.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. In a signalling apparatus, the combination of an electro-magnet and armature
vibrated by current impulses over a main line, a serrated or notched plate, an
electro-magnet in a normally closed local circuit for moving said plate against a
retractile force across the path of the vibrating armature and a retarding device in
connection with the said plate for restraining and slowing the movement thereof, a
portion of the notches in said plate being of greater depth than the others whereby

page_text: the armature will engage with and arrest the plate when entering a shallow notch,
but will pass through the plate when encountering a deeper one, as set forth.
2. In a signalling apparatus, the combination of an electro magnet and armature
vibrated by current impulses over a main line, a serrated or notched plate, and a
retarding device connected therewith, an electro magnet in a normally closed local
circuit for moving said plate against a retractile force across the path of a vibrating
armature or an extension thereof, and a circuit breaker in said local circuit, the
serrations or notches in the plate being of unequal depth whereby the vibrating
armature will engage with and arrest the plate when entering a shallow notch, but
will pass through said plate and engage the local circuit breaker when encountering
a deep notch.
3. In a signalling apparatus, the combination of an electro-magnet and armature.
vibrated by current impulses over a main line, a serrated or notched plate, and a
retarding device connected therewith, an electro-magnet in a normally closed local
circuit, an armature therefor connected with and adapted to move the notched plate
against a retractile force across the path of the vibrating armature circuit closing
or signalling device adapted to be set in operation by the armature when it has
reached a given point in its approach to its magnet, and a circuit breaker in the
circuit of said magnet, these parts being arranged as herein described and the
movable plate being provided with notches of unequal depth hereby the vibrating
armature will engage with and arrest the plate by its engagement with the shallow
notches, but will pass through said plate when it encounters a deeper notch and
operate the local circuit breaker, as herein set forth.
4. In a signalling system, the combination with a local signalling instrument
adapted to be operated or started by the movement of an armature to a pre-
determined point, an electro-magnet in normally closed local circuit, an armature
constituting the means for starting the local signalling mechanism, an automatically
retracted plate connected with and moved by the armature, and serrated or formed
with notches of unequal depth disposed in a definite order, of means for starting or
operating the local signalling mechanism consisting essentially of an automatic
transmitter at the main station adapted to transmit a succession of long and short
impulses corresponding to the order of notches in the plate at the local station, a
magnet at the local station and an armature normally locking said plate and adapted
when vibrated by the impulses produced by the appropriate transmitter to engage
with the short notches only in the plate, as set forth.
5. In a signalling apparatus, the combination with the shaft C¹ carrying the
curved and serrated or notched plate or bar, an escapement and intermediate pawl
and ratchet connection between the escapement wheel and shaft C, whereby the
movement of the latter in one direction only is retarded, a rack engaging with a
pinion on the shaft, an electro-magnet in a normally closed local circuit for moving
said rack in one direction and a spring for retracting it.
6. The combination, with the armature lever and extension thereon vibrated by
current impulses over the main line, and a lever pivoted to a fixed support carrying
a blade at one end and connected by a link to the armature lever at the other, of
the curved arc-shaped plate provided with shallow notches with which the armature
lever and the blade engage and deep notches through which the lever may pass
without engaging the plate, the said plate being capable of movement across the
path of the armature lever when disengaged therefrom, as set forth.
7. The combination with a main line or circuit of a main office or station and
two or more local or way stations, automatic transmitters at the main office, one
for each local station and each adapted to transmit a definite number of long and
short impulses in a certain order, an electro-magnet and armature at each local
station included in a normally closed circuit, a signalling or transmitting instrument
adapted to be started in operation by a movement of the armature of predetermined
extent, a swinging plate with notches of unequal depth connected with the said
armature, a magnet and an armature vibrated by impulses of current in the main

page_text: line and engaging with the swinging plate, and means substantially as described for
interrupting the movement of a plate and returning it to its starting position when
the signals or impulses transmitted fail to correspond with the combination
represented by the order of shallow and deep notches in said plate.
• Dated this 23rd-day of January 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents. for the Applicant.