IMPROVEMENTS IN AND RELATING TO ELECTRICAL SIGNAL APPARATUS
Year: 1879

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
A
and Co., Patent Agents, Southampton Buildings, London, for the Invention of
"IMPROVEMENTS IN AND RELATING TO ELECTRICAL SIGNAL APPARATUS."
communication from abroad by Francis Blake, junior, of Weston, Massa-
chusetts, United States of America.
Sealed the 1st June 1880, and dated the 11th December 1879.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 11th December 1879.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, and Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN AND RELATING
ELECTRICAL SIGNAL APPARATUS." [A communication from abroad by Francis
Blake, junior, of Weston, Massachusetts, United States of America.]
ΤΟ
This Invention relates to electric signalling apparatus, and comprises the employ-
ment of a pendulum hung as the armature of an electro-magnet in connection with
a devico for automatically making and breaking the circuit, to which the electro-
magnet helongs, at intervals corresponding to the rate of vibration of the pendulum.
It also comprises the employment of a series of pendulums of different lengths, in
connection with a series of electro magnets in a common circuit, and a suitable
device for automatically making and breaking the circuit at intervals corresponding
to the rate of vibration of either pendulum. It further comprises the employment
of two pendulums vibrating in equal times, one hung as the armature of an electro-
magnet, and the other operating a circuit closer to make and break the circuit
containing the electro magnet at each vibration. The said Invention also comprises
various details of construction.
It is well known that a pendulum will continue its vibration, if impulses are
imparted to it, at intervals corresponding with its own time or rate of vibration,
and that a pendulum which has been put in motion will soon stop if impulses
imparted to it, though at regular intervals, are at variance with the rate of the
pendulum, since in the latter case an impulse will soon act in a direction opposite to
the direction in which the pendulum happens to be travelling. It is therefore
evident that if an armature be hung as a pendulum at rest in front of an electro-
magnet the armature may be made to take up and continue its vibrations according
Price B1

page_text: to its rate as a pendulum by making and breaking the circuit at intervals corre-
sponding with that rate.
It is also well known that the time of vibration of a pendulum varies according
to its length. If two armatures be hung as pendulums of different lengths before
their respective electro-magnets, one will require a making and breaking of the
circuit in different time from the other, in order to take up and continue its vibra-
tion at its own rate; and not only this, but it follows that impulses at intervals
which would cause one of the armatures to vibrate at its own rate would, if they
disturbed the other a little at first, soon cause it to stop.
If then two electro-magnets having armatures both swinging as pendulums, but
as pendulums of different lengths, are placed in a circuit, it is evident that either
pendulum may be made to vibrate while the other remains at rest, provided there
is introduced into the circuit a device which will make and break the circuit at
regular intervals corresponding with the rate of vibration of either pendulum at the
will of the operator.
For pendulums of the same length the time of the vibration is the same whatever
the pendulum may be made of, and I avail myself of this property or law, for the
purpose of this Invention, by making one pendulum, which may be termed the
controlling pendulum, to cause another to take up and continue corresponding
vibrations, and further, by causing any one of a series of pendulums to take up
and continue its vibrations at its own rate, without essentially disturbing any
other pendulum in the series.
In carrying the said Invention into practice I provide a pendulum with a bob
or weight sufficiently heavy. to enable it to continue its vibrations, when once
commenced, for a considerable period, and I so arrange it in connection with an
electric circuit containing several electro-magnets with armatures suspended before
them as pendulums of different lengths that the circuit is made and broken at
each vibration. If this pendulum with a heavy bob is of the same length as
either of the other pendulums the other pendulum, which is of the same length,
and that one alone, will respond to the vibrations. And it is evident that the
controlling pendulum may be made of any required length by giving it a
shifting bob.
In applying this Invention for ringing a bell from a central station at any one
of three other or out stations in a circuit, without ringing the bell at either of the
other out stations, I provide apparatus constructed as follows, that is to say :-
At each of the three out stations there is a call-bell secured to a frame, and
having in front of it a bell hammer mounted upon a spring. Under each of the
bells there is an electro magnet held in position by a clamp. Still further in front
of the electro magnets are three pendulums having their axes journalled in posts,
and differing each from the others only in respect to length. The bob or weight
of each pendulum is of soft iron, and serves as an armature for the electro-magnet
before which it is hung. For the purposes of adjustment to and from the pendulum
the electro magnet, bell, and bell hammer of each station arc secured to an inter-
mediate table, which is adjustable upon the main table by means of screws
and slots.
Upon a table at the central station there are two metallic posts, between which
is hung the pendulum. to which I have hereinbefore referred as a controlling
pendulum. This pendulum has a shifting bob. The bob is held at any desired
position on the rod by a set screw. The pendulum rod is secured to a rock shaft
or axis having journals near the tops of the posts, the said rock shaft, however,
having a box wood collar to insulate it from one of the posts. The rock shaft
projects beyond this post, and to the projecting part is secured a platinum plate for
an electrode, the other electrodo being a platinum pointed metallic spring attached
to a brass thumb-screw inserted in the post last named. The two electrodes come
in contact at each vibration of the controlling pendulum, the thumb screw
permitting an adjustment to limit the diameter of the contact. The thumb screw
has a set screw. There are two screw cups having wires leading to the battery.

page_text: A wire connects one of the screw cups with the last named post, the other screw
cup being connected by a wire with the electro-magnet at the nearest out station.
Wires connect the several electro magnets, and in experimenting with the apparatus
the electro-magnet at the farther out station should be connected by a wire with
the other post, although in the practical working of the said Invention the farther
electro magnet and this post will be grounded.
The operation is as follows:-The operator at the central station wishing to call
one of the three out stations, adjusts his pendulum so that it is of the same length
as the pendulum at the station he wishes to call, the rod of his own pendulum
being graduated for this purpose. He then sets his pendulum in motion, and at
each vibration the electric circuit is made and broken between the two electrodes,
and as often as this happens the several electro magnets attract their armatures.
For reasons already given, the pendulum at the station whose attention is desired
takes up its regular vibrations, and finally strikes the spring to which the bell-
hanmer is attached with sufficient force to ring the bell.
In actual practice the controlling pendulum is not strictly of the same length as
the pendulum which is to respond to its vibrations, as it is found necessary to
employ pendulums having a greater amplitude than 3°; the required length of the
controlling pendulum for causing the responding pendulum to sound its bell after
the fewest possible vibrations, will be found by experiment.
The arrangement by which one pendulum is caused to take up and repeat the
vibrations of another, may be applied for various useful purposes, for instance,
pendulums of an uniform length may be used at the several out stations in con-
nection with electric signalling apparatus; the responding pendulum might be
arranged to operate a switch to ground the line or to shunt the circuit momentarily
through a magneto bell at each vibration, while the controlling pendulum could
have a switch upon its axis by which a magneto current could be sent into the line
at each vibration. The switch so operated by the responding pendulum should be
constant, while the switch upon the axis of the controlling pendulum should be
adjustable, that it might be made to work in unison with the switch, or shunt
either responding pendulum at pleasure.
It is obvious that the exact arrangement of the bell mechanism employed in
putting this Invention into practice for the purpose of giving signals is not essential.
Indeed, for some signalling purposes, it will be sufficient to merely cause the
pendulum at the selected out station to vibrate at its own rate. And again, when
so vibrating, the pendulum might, in a great variety of ways, be made to give an
alarm.
Again, although the use of a controlling pendulum for closing the circuit, as and
for the purpose described, is a part of this Invention, it is obvious that other
devices iuight be employed as circuit closers, without departing from the principles
of the said Invention. For instance, a circuit-closer constructed upon the principle
of those employed in electric annunciators and fire alarins might be used, clock-
work causing them to operate with precision; and the series of pendulums
belonging to the out stations might be arranged in connection with a closed circuit
or an open divided circuit, so as to be operated each by an independent controlling
pendulum of corresponding length, instead of all being operated by a single con-
trolling pendulum with a shifting bob.
It is obvious that instead of employing an open circuit with a device for making
and breaking it, as and for the purposes above described, a closed circuit might
be employed with any suitable device for shunting the circuit, so as to vary its
strength at intervals corresponding to the rate of one or another of the pendulums
as desired, without departing from the principle of this Invention.
The adjustment of each armature to its magnet should be such that it will not
reach its bell hammer until a number of impulses have been sent through the
line.

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
10th June 1880.
"
TO
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. IMPROVEMENTS IN AND RELATING
ELECTRICAL SIGNAL APPARATUS." A communication from abroad by Francis
Blake, junior, of Weston, Massachusetts, United States of America.
This Invention relates to electrical signalling apparatus, and comprises the
employment of a pendulum hung as the armature of an electro magnet in connec-
tion with a device for automatically making and breaking the circuit, to which the
electro-magnet belongs, at intervals corresponding to the rate of vibration of the
pendulum. It also comprises the employment of a series of pendulums of different
lengths in connection with a series of electro magnets in a common circuit, and a
suitable device for automatically making and breaking the circuit at intervals
corresponding to the rate of vibration of either pendulum. It further comprises
the employment of two pendulums vibrating in equal times, one hung as the arma-
ture of an electro magnet, and the other operating a circuit closer, to make and
break the circuit containing the electro magnet at cach vibration. The said
Invention also comprises various details of construction hereinafter described.
When the length of a pendulum remains the same it always vibrates in the same
time, whatever be the amplitude of its vibration within 3°. This is one of the laws
governing the oscillation or vibration of a pendulum, and it follows that a pendulum
will take up and continue its vibration if impulses are imparted to it at intervals
corresponding with its own time or rate of vibration, and that a pendulum which
has been put in motion will soon stop if impulses imparted to it, though at regular
intervals, are at variance with the rate of the pendulum, since in the latter case an
impulse will soon act in a direction opposite to the direction in which the pendulum
happens to be travelling. It is therefore evident that if an armature be hung as a
pendulum at rest in front of an electro magnet the armature may be made to take
up and continue its vibrations according to its rate as a pendulum by making and
breaking the circuit at intervals corresponding with this rate.
Another law governing the oscillation or vibration of the pendulum is, that for
pendulumns of unequal length the times of vibration are unequal. The exact law
is, that for pendulums of unequal length the time of vibration is proportioned to
the square root of the length; but for the purposes of this Invention it is sufficient
to observe the law in the general terms first stated. It follows that if two arma-
tures be hung as pendulums of different lengths before their respective electro-
magnets one will require a making and breaking of the circuit in different time
from the other, in order to take up and continue its vibration at its own rate; and
not only this, but it follows that impulses at intervals which would cause one of the
armatures to vibrate at its own rate would, if they disturbed the other a little at
first, soon cause it to stop.
If then two electro magnets having armatures both swinging as pendulums, but
as pendulums of different lengths, are placed in a circuit, it is evident that either
pendulum may be made to vibrate while the other remains at rest, provided there
is introduced into the circuit a device which will make and break the circuit at
regular intervals corresponding with the rate of vibration of either pendulum, at
the will of the operator.
For pendulums of the same length the time of the vibration is the same whatever
the pendulum may be made of. This is another law respecting the pendulums, and
I avail myself of this property or law for the purposes of this Invention by making
one pendulum, which inay be termed the controlling pendulum, to cause another to
take up and continue corresponding vibrations; and further, by causing any one of

page_text: Figure 5, & sine elevation, and
Figure 6, a plan of the apparatus at the central station.
The mechanism in Figures 1, 2, and 3 is shewn as mounted upon a common table
A. At each of the three out stations there is a call bell B secured to a frame f, and
having in front of it a bell hammer / mounted upon a spring, as shown. Under
each of the bells is an electro-maguet E held in position by a clamp c.
Still further
in front, in front of the electro-magnets, are three pendulums P1, P2, P³, having their
axes journalled in posts p, p, p, p, and differing each from the others only in respect
to length. The bob or weight of each pendulum is of soft iron, and serves as an
armature for the electro-magnet before which it is hung. For the purposes of
adjustment to and from the pendulum the electro-magnet bell and bell hammer of
each station are secured to an intermediate table a, which is adjustable upon the
main table by means of screws s and slots, as shewn.
A is a table at the central station, upon which are two metallic posts C, C¹;
between these posts is hung the pendulum, herein before referred to as a controlling
pendulum; this pendulum consists of a rod r and has a shifting bob_or weight G;
the bob is held at any desired position on the rod by a set screw W. The pendulum
rod is secured, as shewn, to a rock shaft or axis having journals near the top of
the posts C, C³, the said rock shaft however having a box wood collar o to insulate
it from the post C¹. The said rock shaft projects beyond the post C, and to the
projecting end is secured, as shewn, a platinum plate e for an electrode, the other
electrode being a platinum pointed metallic spring e¹ attached to a brass thumb
screw t inserted in the post C¹, as shewn. These two electrodes come in contact at
each vibration of the controlling pendulum, the thumb screw t permitting an
adjustment to vary the contact. This thumb screw has a set screw w³. J, J, are
two screw cups or terminals having wires leading to the battery. A wire connects
one of the screw cups with the post C¹, the other screw cup being connected by a
wire with the electro-magnet at the nearest out station. Wires connect the several
electro-magnets, and in experimenting with the apparatus shewn in the Drawing
the electro magnet at the further out station should be connected by a wire with
post C, although in the practical working of the said Invention the farther electro
magnet and the post C will be grounded.
The operation of the aforesaid devices is as follows:-The operator at the central
station wishing to call one of the three out stations adjusts his pendulum so that it
is of the same length as the pendulum at the station he wishes to call, the rod of
his own pendulum being graduated for this purpose. He then sets his pendulum
in motion, and at each vibration the electric circuit is made and broken between

page_text: the two electrodes e, e¹, and as often as this happens the several electro magnets
attract their armatures. For reasons already given, the pendulum at the station
whose attention is desired takes up its regular vibrations and finally strikes the
spring to which the bell hammer is attached with sufficient force to ring the bell.
In actual practice the controlling pendulum is not strictly of the same length as
the pendulum which is to respond to its vibrations as it is found necessary to
employ pendulumns having a greater amplitude than 3°. The required length of
the controlling pendulum for causing the responding pendulum to sound its bell
after the fewest possible vibrations will be found by experiment. It is unnecessary
to do more than suggest other useful applications of that part of my Invention
which consists in causing one pendulum to take up and repeat the vibrations of
another. In one of these applications pendulums of an uniform length may be used
at the several out stations in connection with electric signalling apparatus. For
instance, the responding pendulum might be arranged to operate a switch to ground
the line or to shunt the circuit momentarily through a magneto electric bell at each
vibration, while the controlling pendulum might have a switch upon its axis by
which a magneto electric current could be sent into the line at each vibration. The
switch so operated by the responding pendulum should be constant while the switch
upon the axis of the controlling pendulum should be adjustable that it might be
made to work in unison with the switch or shunt either responding pendulum at
pleasure.
It is obvious that the exact arrangement of the bell inechanism employed in
carrying this Invention into practice for the purpose of giving signals is not
essential. Indeed for some signalling purposes it will be sufficient to merely cause
the pendulum at the selected out station to vibrate at its own rate.
And again,
when so vibrating, the pendulum might in a great variety of ways be made to give
an alarm.
Again, although the use of a controlling pendulum for closing the circuit as and
for the purpose described is a part of this Invention, it is obvious that other devices
might be employed as circuit closers without departing from the principles of the
said Invention. For instance, a circuit closer constructed upon the principle of
those employed in electric annunciators and fire alarms might be used, clock work
causing them to operate with precision, and the series of pendulums belonging to
the out stations might be arranged in connection with a closed circuit or an open
divided circuit so as to be operated each by an independent controlling pendulum
of corresponding length instead of all being operated by a single controlling
pendulum with a shifting bob.
It is obvious that instead of employing an open circuit with a device for making
and breaking it, as and for the purposes above described, a closed circuit might be
employed with any suitable device for shunting the current so as to vary its
strength at intervals corresponding to the rate of one or another of the pendulums
as desired, without departing from the spirit of this Invention.
The adjustament of each armature to its magnet should be such that it will not
reach its bell hammer until a number of impulses have been sent through the line.
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 under-
stood that I claim,―
First. In combination with a bell and bell hammer a pendulum hung as the
armature of an electro magnet with a suitable device for automatically making and
breaking the circuit or varying the strength of the current flowing through the
circuit to which the electro magnet belongs, at intervals corresponding to the rate
of vibration of the pendulum, substantially as above described.
Second. A series of pendulums of different lengths in combination with a series
of bells and electro magnets in a common circuit and a suitable device for making and
breaking the circuit or varying the strength of the current flowing through the
circuit at intervals corresponding to the rate of vibration of cither pendulum,
substantially as above described.

page_text: Third. The combination of two pendulums of substantially equal length, one
hung as the armature of an electro magnet and provided with a bell and bell
hammer and the other operating a circuit closer to make and break the circuit
containing the electro magnet at each vibration, substantially as above described.
Fourth. The posts C, C³, the axis & with the pendulum suspended therefrom, the
collar o, the plate e, the spring e', and the thumb screw t in combination with an
electric circuit, substantially as above described and for the purpose specified.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Tenth day of June, in the year of our Lord One
thousand eight hundred and eighty.
DART
W. ROB. LAKE. (L.S.)