IMPROVEMENTS IN ELECTRIC SIGNALLING APPARATUS CHIEFLY DESIGNED FOR TELEPHONIC PURPOSES
Year: 1882

page_text: LETTERS PATENT to William Robert Lake, of the firm of Haseltine Lake
& Co., Patent Agents, Southampton Buildings London for an Invention of
"IMPROVEMENTS IN ELECTRIC SIGNALLING APPARATUS CHIEFLY DESIGNED
FOR TELEPHONIC PURPOSES Communicated to him from abroad by James
Hussey Cary of Boston, Massachusetts, United States of America
"
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 6th September 1882.
"
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, and Co., Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN ELECTRIC SIGNALLING APPA-
RATUS CHIEFLY DESIGNED FOR TELEPHONIC PURPOSES [A communication to him
from abroad by James Hussey Cary of Boston, Massachusetts, United States of
America]
This Invention relates to electric signals or signalling apparatus of that class
which are adapted to be used in circuits, in any number, known as individual
signals, and arranged to be operated from a central station, in such a manner that
the bell in the desired sub-station only of the whole series will be rung.
The said Invention comprises certain improvements whereby each signal in the
circuit is operated positively and accurately and the possibility of failure to operate,
or of incorrect operation, is reduced to the minimum; it also comprises certain
improved devices for bringing all the signals to unison when desired, all of which
are hereinafter described.
In carrying the said Invention into practice I provide a base piece upon which
is arranged an electro-magnet, having a neutral armature, hung on pivots and kept
from the electro-magnet by a retractile spring. To the said armature is attached
an upwardly projecting arm to which is pivotted a dog or pawl. A horizontal
shaft is supported by suitable bearings on a post and a ratchet is secured to the said.
shaft and arranged to be rotated step by step by means of the said dog or pawl;

page_text: another ratchet is secured to the said shaft and has its teeth arranged opposite in
direction to the teeth of the aforesaid ratchet. A lever or detent is pivotted to an
arm on a standard; one end of this lever is provided with an inclined slot into
which projects a pin on the aforesaid projecting arm. The opposite end of the said
lever is caused by the said slot and pin to automatically approach and recede from
the second ratchet when the said projecting arm is oscillated. A spring contact is
arranged to bear against the aforesaid shaft and is connected with the call-bell
accompanying the instrument.
To the said shaft is attached a circuit-breaker which consists of a disc of metal
having a notch or recess in its periphery. A spring is connected with the outward
line, and arranged to bear on the periphery of the said disc except when the recess
of the said disc coincides with the spring, when the contact ceases and the circuit
through the instrument is broken. I also provide an indicator card or dial having
marked upon its circumference, the numbers of the stations in the circuit, in
addition to which are two spaces, marked respectively to indicate "central office"
and "line in use. One of these spaces is the unison space of all the instruments.
A pointer is attached to the end of the aforesaid shaft and rotated thereby, step by
step, over the said dial.
"
The circuit breakers at each sub-station are fixed upon their shafts with tho
recesses in the discs in different positions relatively to the pointers so that the
circuit will be broken in only one of the instruments in the series at a time.
When the instruments in the circuit are at unison the circuit through each will
be from the inward line through the electro-magnet, the said shaft, disc, and contact
spring to the outward line, or ground.
When the circuit is broken at any sub-station, the circuit is through the inward
line, the electro magnet and suitable metallic connections to the call-bell, at the
sub-station, and through the call-bell to ground. When the operator at the central
station desires to call a sub-station in the circuit, he presses a battery key the
required number of times in succession, thereby sending to line the same number
of pulsations.
I prefer to employ magneto currents for the purpose of ringing the bell.
The slot in the aforesaid lever is so arranged relatively to the rotation of the
first named ratchet that the detaining end of the said lever is raised from the
second ratchet before the dog or pawl commences to rotate the first ratchet and is
caused to fall upon the second ratchet and prevent the shaft from rotating more
than a single step, thus preventing any further movement which might ensue, from
the inertia of the moving parts, and bring the pointer to the wrong number or
division of the dial. The operation of the apparatus is thus made positive and
accurate and the possibility of accident or incorrect operation is obviated, in a great
measure.
I do not limit myself to operating the signal by magneto or other currents sent
from the central office, for the circuit breaker may be caused to connect a local
battery with a vibrating bell at each sub-station, which battery will operate the
bell and will be disconnected by the next movement of the circuit-breaker. Or a
vibrating bell may be connected to the central office battery by the action of the
circuit breaker, and rung while the central office key remains depressed, that is to
say, before the said key is released after the depression which caused the circuit
breaker to operate.
In the adjustment of the signalling apparatus to sound a call at any sub station
on the line in case vibrating battery bells are used, the vibrating armatures of the
bells can be so adjusted that the circuit breaker may be caused to pass each sub-
station which it is not desired to call, in such rapid succession that the circuit at
the said sub-stations will not remain open for sufficient length of time to cause the
ringing of the said bells so passed: but upon the detention of the circuit breaker
at any desired point for a sufficient length of time the desired bell will be rung.
A spring bearing with a yielding pressure against the aforesaid shaft acts as a

page_text: brake to prevent the dog or pawl from backwardly rotating the said shaft, when
the dog or pawl is moving forward over the first named ratchet to engage with
another tooth of the said ratchet.
I provide a polarized armature pivotted between the poles of the aforesaid electro
magnet and adapted to vibrate between the said poles, and be held in either of two
positions according as it is attracted to one pole or the other. When attracted to
one pole its upper end will stand in the path of a pin on the aforesaid shaft and
arrest the said pin and shaft. The pins of all the instruments are so arranged that
when they are arrested the pointers of the instruments will coincide with certain
spaces so that by sending currents of a given polarity through the electro magnets
the operator at the central office can arrest all the pointers at the same point.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Robert Lake in the Great Seal Patent Office on the 6th
March 1883.
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, London "IMPROVEMENTS IN ELECTRIC SIGNALLING APPA-
RATUS, CHIEFLY DESIGNED FOR TELEPHONIC PURPOSES " A communication to me
from abroad by James Hussey Cary, of Boston, Massachusetts, United States of
America.
This Invention relates to electric signals or signalling apparatus of that class
known as "individual signals" which are adapted to be used in circuits, in any
number, and arranged to be operated from a central station, in such a manner, that
only the bell in the desired sub-station of the whole series will be rung.
The said Invention comprises certain improvements whereby each signal in the
circuit is operated positively and accurately and the possibility of failure to operate,
or of incorrect operation, is reduced to the minimum; it also comprises certain
improved devices for bringing all the signals to unison when desired, all of which
are hereinafter described.
In the accompanying drawing.
Figure 1 is a top view or plan of apparatus constructed according to this
Invention.
Figure 2 is a side view, showing the face of the indicator.
Figure 3 is a section on the line xx Figure 1. Figures 4, 5 and 6 are sections
on the lines y-y, 2-z, and 2'-21, respectively of Figure 1.
Figure 7 is a front view of a part of the mechanism.
Similar letters of reference indicate corresponding parts throughout the
drawing.
A is a base piece upon which the various parts are arranged, M is an electro-
magnet, and B is an armature, hung upon pivots and kept from contact with the
electro-magnet by the spring s. To the said armature is attached an upwardly
projecting arm a, to which is pivotted a dog or pawl c. e, is a horizontal shaft
supported in bearings g, g, on a post b; f is a ratchet wheel secured to the said
shaft and arranged to be rotated step by step by means of the dog or pawl c;
another ratchet wheel l, is secured to the said shaft, and has its teeth arranged in
an opposite direction to the teeth of the ratchet wheel f. h is a lever or detent
pivotted at h¹ to an arm on the standard b; one end of the lever h is provided with
an inclined slot h² into which projects a pin a', on the arm a. The opposite end
of the said lever h, is caused by the said slot and pin to automatically approach
and recede from the ratchet wheel 1, when the arm a is oscillated. i is a spring
contact piece arranged to bear against the shaft e, and connected with the call bell
accompanying the instrument
To the shaft e is attached a circuit breaker o, which consists of a disc 2 of metal
having a notch or recess in its periphery. A spring 3 is connected with the wire
and arranged to bear on the periphery of the said disc, as shown in Figure 6,
except when the recess of the disc coincides with the spring when the contact
ceases, and the circuit through the instrument is broken. "g' is an indicator card
or dial having marked upon its face the numbers of the stations in the circuit, in
addition to which are two spaces marked respectively to indicate "central office "
and "line in use." The space on the indicator card marked "CO" is the unison
space of all the instruments. p is a pointer attached to the end of the shaft e, and
rotated thereby step by step over the dial g¹.

page_text: The circuit-breakers o at each sub-station are fixed upon their shafts e with the
recesses in the discs 2 in different positions relatively to the pointers p, so that
the circuit will be broken in only one of the instruments in the series at the
same time.
When the instruments in the circuit are at unison, or when all their pointers p
point to the space "CO" the circuit through each will be from the + wire
through the electro magnet, the shaft e, the disc 2 and the contact spring 3 to the
wire or ground.
-
When the circuit is broken at any sub-station the circuit is through the + wire,
the electro-magnet M, and suitable metallic connections, to the call bell, at the sub-
station, and through the call bell to ground.
In the operation of the said invention, suppose the operator at the central
station desires to call sub-station N° 4 in the circuit, he presses a button four
times in succession, thereby causing four pulsations each of which causes the
armatures at all the sub-stations to be attracted to their respective electro-
magnets M and to draw the dogs or pawls c with them, thus rotating the ratchet
wheels and shafts e, and causing the pointers p to rest opposite the space
marked 4 on the several dials. The circuit-breakers o at the several instruments
are so arranged, that when the pointers stand at 4, as described, the circuit-breaker
at station number 4 only, will break the main line circuit. The signal bell at sub-
station four is now added to the main line circuit, and to ring the said bell, the
operator at the central station sends through the line, which now includes the bell
at sub-station 4, but no other bell, currents of electricity of insufficient strength to
cause the armatures B to be attracted to the electro-magnets, but strong enough to
ring the bell.
I prefer to employ magneto-electric currents for the purpose of ringing
the bell.
After sounding a call at any required station the battery current is used to set
the signals at the point "line in use," and again at the termination of the
conversation to set the signal at the point "C." O." This leaves the alternating
armatures of the magneto-electric bells charged usually with the same polarity, and
the use of the same current again will not cause them to strike. Or if by chance
one of the armatures should be reversed at the time of the impulse of the battery
passed through a magneto-electric bell in the process of calling some station
beyond, it could only give one light tap which could never be mistaken for the
signal which is a long and distinct peal on the said bell. It has been shown by
actual experiment that in the course of several hundred calls the bells do not ring
except at the station wanted.
The slot h³ in the lever h is so arranged relatively to the rotation of the ratchet-
wheel that the detaining end of the lever his raised from the ratchet-wheel
before the dog or pawl c commences to rotate the ratchet-wheelf and is caused to
fall upon the ratchet-wheel and prevent the shaft e from rotating more than a
single step, thus preventing any further movement which might ensue, from the
inertia of the moving parts and bring the pointer p to the wrong number or
division of the dial. The operation of the apparatus is thus inade positive and
accurate and the possibility of accident or incorrect operation is obviated in a great
measure.
I do not limit myself to operating the signal by magneto or other currents sent
from the central office, for the circuit breaker may be caused to connect a local
battery with a vibrating bell at each sub-station, which battery will operate the
bell and will be disconnected by the next movement of the circuit breaker. Or a
vibrating bell may be connected to the central office battery by the action of the
circuit breaker, and rung while the central office button remains depressed, that is
to say, before the said button is released after the depression which caused the
circuit breaker to operate.
In the adjustment of the signalling apparatus to sound a call at any sub-station
on the line, in case vibrating battery bells are used, the vibrating armatures of the

page_text: bells can be so adjusted, that the circuit breaker may be caused to pass each
sub-station which it is not desired to call, in such rapid succession that the circuit
at the said sub stations will not remain open for sufficient length of time to cause
the ringing of the said bells so passed, but upon the detention of the circuit
breaker at any desired point for a sufficient length of time the desired bell will be
rung. If by detaining the key or button a moment too long, a stroke or two of
the bell should be struck, it would readily be distinguished from the continuous
peal intended for a call
Springs bearing with a yielding pressure against the shaft e act as brakes to
prevent the dog or pawl c from backwardly rotating the said shaft when the dog
or pawl is moving forward over the ratchet-wheelf to engage with another tooth
of the said ratchet.
P indicates a polarized armature, pivoted at Q, between the poles of the electro-
magnet M and adapted to vibrate between the said poles, and be held in either of
two positions according as it is attracted to one pole or the other. When attracted
to one pole its upper end will stand in the path of a pin R, on the shaft e and
arrest the said pin and shaft. The pins R of all the instruments are so arranged
that when they are arrested the pointers of the instruments will coincide with the
spaces "C. O." It will thus be seen that by sending currents of a given polarity
through the electro-magnets M the operator at the central office can arrest all the
pointers at the same point
Having thus fully described the said Invention as communicated to me by my
foreign Correspondent, and the manner of performing the same, I wish it understood
that I Claim.
First-In an electric signalling apparatus, a shaft carrying a circuit-breaker and
a ratchet-wheel, an electro-magnet having an armature provided with a device for
rotating the said shaft by means of its ratchet-wheel step by step, a detent adapted
to engage with a ratchet-wheel and prevent forward rotation of the shaft, and
automatic devices whereby the said detent is intermittently operated and each
forward step or rotation of the shaft is limited as set forth.
Second The combination of the shaft having the circuit-breaker, the
oppositely toothed ratchet-wheels f, l, the dog or pawl c actuated by the armature
of the electro-magnet and engaging with the ratchet-wheel f, the pivoted lever h,
engaged intermittently with the ratchet-wheel l, and serving as an automatic detent
to limit the step by step rotation of the shaft as set-forth.
:-
Third The combination of the shaft e, having the circuit-breaker, means
substantially as described for rotating the said shaft step by step, the pin R on the
shaft, and the polarized vibrating armature adapted, when in one position, to arrest
the said pin as set-forth.
In witness whereof I the said William Robert Lake have hereunto set
my hand and seal this sixth day of March in the year of our Lord One
thousand eight hundred and eighty three.