IMPROVEMENTS IN AND RELATING TO CALL OR SIGNAL APPARATUS FOR TELEPHONIC OR TELEGRAPHIC PURPOSES
Year: 1880

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 AND RELATING TO CALL OR SIGNAL APPARATUS FOR
TELEPHONIC OR TELEGRAPHIC PURPOSES." A communication from abroad
by Charles Sumner Eaton, of Lowell, Massachusetts, United States of
America.
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents on the 25th May 1880.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN AND RELATING TO CALL
A com-
OR SIGNAL APPARATUS FOR TELEPHONIC OR TELEGRAPHIC PURPOSES."
munication from abroad by Charles Sumner Eaton, of Lowell, Massachusetts,
United States of America.
This Invention relates to call or signal apparatus for telephonic or telegraphic
purposes.
Where a number of telephones are included within a single electrical circuit, as
heretofore, and the operator at one station wishes to communicate with another
station, he sounds on the electric signal or call bell of the receiving station the
number by which it is designated to call the attention of the attendant at that
station. As, however, the signal bells of all of the stations are in the same circuit
the signal is sounded simultaneously at every station, causing a great annoyance
by reason of the frequent ringing of the bells and the necessity for the attendant
at each station to be constantly on the alert, in order to distinguish the different
signals and recognize that of his station, so as to know when it is called.
To avoid this simultaneous ringing of all of the signal bells of the different
stations in an electrical circuit, and to cause only the bell at the particular station
to which the message is to be sent to be sounded while the others remain silent is
the object of this Invention, which consists in certain novel devices for effecting the
desired result, as hereinafter fully set forth.
In the accompanying Drawing,
Figure 1 is a front elevation of my improved call or signalling apparatus.
Figure 2 is a front elevation of the same, the dial and a portion of the casing
haine romareed to show the interior construction.

page_text: Figure 3 is a vertical section through the same on the line x, x, Figure 1, with
part in side elevation.
Figure 4 is a detail view of a portion of the mechanism drawn to an enlarged
scale.
Like letters indicate the same parts throughout the Drawing.
A represents a casing within which is secured the frame B of a train of clock-
work C, which is actuated by a spring a and is provided with a "dead beat'
escapement. The plate b (carrying at its ends the pallets c, d, which engage with
the teeth of the escapement-wheel e), is provided with a rod or wire which is
attached to its underside and is vibrated by an arm g projecting up from the
armature of an electro-magnet D, the upper end of the arm g passing through a
loop at the lower end of the rod f. The electro-magnet D is secured upon a suitable
shelf within the casing A, and has its coils connected with the main line wire by
the wires, k, so that it can be operated from any of the stations within the circuit
in which the instruments are placed, including its own station, by means of a
suitable key E at each station to cause the armature h to be vibrated in the usual
manner. Each movement of the armature h in either direction causes or allows the
escapement wheel e to rotate a distance equal to half that between two of its
contiguous teeth, and by the employment of a "dead beat" escapement when the
armature is drawn away from the magnet the pallet d will catch and hold the
tooth which bears against it and prevent the escapement-wheel from again moving
until the rod f is vibrated in the opposite direction by the attraction of the
armature to the magnet; and thus as the electro magnet D is operated the escape-
ment wheel e is caused or allowed to revolve intermittingly, for a purpose to be
hereafter described.
To the outer end of the arbor m of the escapement wheel e is secured an index
hand or pointer G which moves over a dial H bearing on its face the numbers of
the telephone stations in the circuit, and certain other numbers, hereinafter referred
to, the numbers on the dial corresponding to the number of teeth of the escapement
wheel e, that is to say, one tooth for each number on the dial. Upon the arbor m
is also secured a wheel or disc I provided with a notch p, and against the periphery
of the disc I rests one end 16 of a nearly balanced lever K, having its fulcrum at q,
the opposite end 17 of this lever being so placed as to come into contact with a
metallic stud or post L when its end 16 is allowed to drop to or nearly to the
bottom of the notch p in the disc I, this contact of the end 17 of the lever K. with
the stud L completing a local circuit, in which the call bell M is included, and giving
an alarm to notify the attendant that it is desired to communicate with his station.
The notch p of the disc I is so placed with respect to the index and G and
dial H that the end 16 of the lever K will drop into it to close the bell-circuit and
give the alarm only when the index-hand points to a particular part of the dial
corresponding to the number of the station to which the instrument belongs; and
to close the bell circuit when the hand is in the position referred to the operator at
the transmitting station must keep the key E depressed a sufficient length of time
to give the end 16 of the lever time to drop to or nearly to the bottom of the
notch p, so that its opposite end 17 will strike the stud L, otherwise the call-bell
will not be rung; when, however, the operator removes his finger from the key E,
allowing it to rise, the circuit through the electro-magnet D is closed, and the disc I
is rotated sufficiently to raise the end 16 of the lever K out or nearly out of the
notch p, and thus open the bell-circuit and stop the ringing of the call bell M.
When the notch p of the disc 1 is carried rapidly past the end 16 of the lever K,
which is effected by releasing the key E instantaneously after each depression, the
end 16 will not have time to drop into the notch p sufficiently far to bring the
other end 17 of the lever into contact with the stud L, but will be caught by the
inclined portion 18 of the notch p and again raised up before the end 17 can come
into contact with the stud, and consequently the call-bell M will not be sounded.
This rapid movement of the notch 2 of the disc I past the end 16 of the lever K
will occur when some other station in the circuit is being called, which will

page_text: necessitate the revolving of the notch p past the end 16 of the lever; and thus it
will be seen that only the call bell at the particular station with which it is desired
to communicate is rung, while all the other bells in the circuit will remain silent,
whereby the annoyance caused by the frequent ringing of the bells is avoided, and
no attention is needed on the part of the operator at any station until he hears his
own call bell or alarm sounded, whereupon he knows that a communication with
him is desired.
The escapement wheels c of the several instruments in the circuit all revolve in
unison, together with the index hands, which are all set to point simultaneously to
the same number on their respective dials, and when the operator at any station
wishes to communicate with another station in the same circuit (for instance, No. 6)
he manipulates the key E (taking care to release it instantaneously after each
depression) until the index hand G points to number 6 on the dial, at which time
the key will be up; he then again depresses the key, this time holding it down
with his finger, which moves the index hand to a point midway between 6 and 7,
and brings the notch p of the disc I of the instrument at the receiving station
under the end 16 of the lever K, which will then drop therein owing to the arbor m
remaining stationary by reason of the continued depression of the key E at the
transmitting station, which causes the call bell at station 6 to ring the alarm in the
manner previously described, this ringing continuing as long as the operator at the
transmitting station keeps his key E depressed. As soon, however, as he thinks a
sufficient alarm has been sounded he removes his finger from the key E, which
produces a movement of the arbor m and causes the end 10 of the lever K of the
receiving station to be raised out or partly out of the notch p, thus opening the
bell-circuit and stopping the alarm. The operator at the transmitting station then,
by means of his key E, moves the index hands G of the several instruments in the
circuit round to a predetermined number on the dials which has no station assigned
to it, for instance, 10, so that when the hands point to this number it will be
indicated to all the other stations that the line is in use; the operator at the
receiving station then, by means of his key E, rotates the index hands G round to
another unassigned number, for instance, 15, and then opens or breaks the electric
circuit in which the electro magnets D are placed, as is necessary in using a
"Bell
telephone, by means of a suitable switch N or by depressing the key E and
retaining it in that position, which will cause the hands Ġ to move half way to
the next number (in this case 1); and when the operator at the transmitting
station sees the hand pointing between 15 and the next number in advance (1) he
knows that the circuit is open and that the operator at the receiving station is
ready to talk.
"
When the conversation has been terminated the circuit is closed by both of the
operators moving the switch N of their respective instruments or allowing the key E
to rise, which causes the armatures of the electro-magnets D to be attracted and
the index hands G to move from the position midway between 15 and 1 to 1,
which indicates to all of the stations that the line is free and ready for use. When,
however, an operator at any station goes to his instrument and finds the hand
pointing to 10 or 15 he knows that the line is in use, and must therefore wait
until the hand indicates that the line is again free.
I do not confine myself to the use of the notched wheel I and lever K, as it
is evident that some other device may be used in connection with the rotating
arbor m, which will set the alarm mechanism in action when the arbor m is held
stationary for a sufficient length of time with the hand pointing to the number or
mark on the dial corresponding to its own station.
Instead of an electric call bell a clock alarm mechanism may be employed, if
preferred, and in lieu of employing a train of clockwork and a spring or weight in
connection with an electro-magnet D to rotate the arbor carrying the device for
setting the alarm mechanisin in action, the arbor may be rotated by a ratchet-
wheel and pawl, or pawls, or other mechanism connected directly with the
vibrating armature h of the electro-magnet. Instead of attaching the index hand G

page_text: and notched disc I to the arbor m of the escapement wheel e, it is evident that they
may be attached to some other arbor properly connected with and revolved by the
train of clock work without departing from the spirit of my Invention.
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 call or signal apparatus an arbor provided with an index
hand, and caused or allowed to rotate intermittingly by the action of an electro-
magnet capable of being operated from any station in an electric circuit, in
combination with a dial bearing the numbers of the stations in the circuit, and a
device or mechanism having a retarded movement and controlled by the said arbor
for setting in action the call bell or alarm mechanism when the arbor is arrested
and held stationary for a sufficient length of time, with the index hand pointing to
the number upon that part of the dial designating the station to which the
instrument belongs, substantially as above set forth.
Second. In an electric call or signal apparatus the intermittingly rotating arbor
provided with an index hand and a notched disc, in combination with the dial and
the lever, having a retarded movement and controlled by the arbor for setting in
action the call bell or alarm mechanism when the end of the lever is allowed to
drop into the notch, substantially in the manner and for the purpose herein
described.
Third. In an electric call or signal apparatus the clockwork operated by the
electro-magnet from any station in the circuit by means of a key, for the purpose
of producing an intermittent rotation of the arbor, in combination with the hand
dial, notched disc, and lever, having a retarded movement and controlled by the
arbor, or equivalent mechanism, for setting in action the call bell or alarm mechanism,
substantially as above described.
Fourth. The combination in an electric circuit of a series of three or more call-
signal instruments, each consisting essentially of an arbor rotated intermittingly, and
provided with a hand moving over a dial, an electro magnet capable of being
operated by means of the key of any station in the circuit, to cause or allow the
arbor to rotate, and means for setting in action the call bell or alarm mechanism,
having a retarded movement and controlled by the arbor when the arbor is arrested
and held stationary for a sufficient length of time with the hand pointing to a
given number, or part, of the dial, all constructed to operate together substantially
in the manner and for the purpose set forth.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Twenty fifth day of May, in the year of our Lord One
thousand eight hundred and eighty.
WM ROBT. LAKE. (L.S.)
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