IMPROVE- MENTS IN TELEPHONIC APPARATUS AND SIGNALS THEREFOR
Year: 1881

page_text: LETTERS PATENT to Philip Middleton Justice, of 14, Southampton Buildings,
in the County of Middlesex, Patent Agent, for an Invention of "IMPROVE-
MENTS IN TELEPHONIC APPARATUS AND SIGNALS THEREFOR." A communication
from abroad by Homer Rice Miller, of South Framington, in the County of
35 111
PROVISIONAL SPECIFICATION left by the said Philip Middleton Justice at
the Office of the Commissioners of Patents on the 16th February 1881.
PHILIP MIDDLETON JUSTICE, of 14, Southampton Buildings, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN TELEPHONIC APPARATUS AND
SIGNALS THEREFOR." A communication from abroad by Homer Rice Miller, of
South Framington, in the County of Middlesex, State of Massachusetts, United
States of America.
This Invention relates to electric speaking telephones and to signalling
mechanisms adapted to be used therewith. The first includes locking mechanisms,
whereby the operator at any given station may lock out all the stations in the
line, excepting his own, and that with which he desires to communicate. The
second part includes an improved electric signal specially designed to be used in
connection with electric speaking telephones, but also capable of independent use.
The object of the first part of my Invention is to secure privacy in telephonic
communication by the temporary exclusion of all other stations in the line,
excepting those between which communication is held. This object has been
partially and imperfectly attained, or has been attempted by means of intricate
mechanisms, difficult and impossible to be operated in practical work. In this
part of my Invention the shunting mechanisms are enclosed in a box, which may
serve as a base for any suitable signalling apparatus. The main line wires are
connected to ordinary posts on the box or case, and extend to the helix of a small
electro magnet swivelled in the upper part of the case. From the other end of the
helix the wire extends to the point where it connects to the wire of the telephone.
It is however in connection with a spring fixed to the board partition or otherwise
insulated on the case, against which rests a metallic switch lever insulated on a
point. This lever carries an insulating block, to which is attached a pronged plate.
From the pivoted ends of the lever connection is made directly to the outer end of

page_text: f
the main line by means of the wire, and when the lever is in contact the circuit is
through the parts just described. At a suitable distance above the lever is a point
connected by wire to an insulated post. The remainder of the circuit consists of
the wire connected to the post, said wire passing through the induction coil in the
transmitter and continuing to a post, and thence through the telephone to its
connection to the part already described. This circuit is completed by the upward
Iovement of the switch lever causing it to press upon an inclined spring end;
the same movement of this lever moves also a pronged plate. The points are bent
at the ends, and when the lever is down the ends bear only on the partition, but
when the lever is raised the prongs are moved so that the point of one rests upon a
curved piece, and the other on a second similar curved piece, forming electrical
connection between then. The first curved piece is connected to one pole of the
transmitter battery by means of a post and connecting wire. The wire from the
other pole passes through the induction coil in the transmitter, and thence to a
terminal post, and reaches the second curved piece through a connecting wire. It
will be apparent from the description given that circuit of the transmitter battery
is made or broken by the movement of the prongs, caused by the movement of the
switch lever, which action, as is well understood, is necessary when the ordinary
The free end of the
Le-Clauche" or a like battery is used with the transmitter.
lever extends through a slot in a vertical rod. This rod passes through guides
fixed to the frame, and has a hook on the lower end, on which the telephone is
hung. The rod is supported upon a spring which rests on the upper guide piece,
and bears underneath a pin in the end of the rod. The slot.in the rod is wider
than the switch bar, and allows the spring to lift the rod slightly without moving
the lever. The tension of the spring is such that the weight of the telephone will
depress the rod so as to bring a notch in said rod opposite the end of a bent lever,
the end of which is fitted to engage with the notch and lock the rod, so that it
cannot be pushed up. The armature of the magnet is attached to the upper end of
the bent lever, the lever being so pivoted upon an arm in the case that the
armature when drawn up shall throw the lower end of the lever out of connection
with the notch, but when not drawn up the armature shall fall back by gravity,
and throw the end of the lever into connection and lock the rod, so that it cannot
be raised. It will be understood from this description of the parts that the magnet
at every station in the line is in the main line circuit. Under ordinary conditions
of the circuit, and when no telephones are switched in, the effect of the current is
to keep the armature drawn up and the rod unlocked; but when an operator at
any given station is called he unhooks and shunts in his telephone. The great
resistance of the telephone then brought into the line so weakens the current that
it will no longer act upon the electro magnet sufficiently to draw up the armature,
and these armatures in the whole circuit of the line will therefore fall back by
their own gravity, and lock all the rods through which the shunting devices are
operated, excepting that from which the telephone has been removed. This
happens of course at the station which has been called, where the operator having
removed the telephone the rod is lifted by the spring sufficiently to raise the notch
above the catch without disturbing the shunting lever as that moves in the slot.
The operator at this station may push up the rod and shunt in his telephone, and
is thus able to communicate with another station without liability of interruption
by the operator at any other station, or that the communication will be heard,
except at the two stations in connection. The operation of the shunting devices is
apparent from the description heretofore given of these devices. By pushing
up the rod the shunting lever is lifted, so that it leaves one point of connection,
and is moved upon a second point, on which it is held by friction.
the same time the points of the plate are shifted so as to enclose the two
curved pieces before described. This movement of the lever shunts in the
telephone, and the movement of the plate closes the circuit of the local battery. A
modification of the locking devices may be made by dispensing with the electro
magnet, and extending the lever up between the arins of the main magnet of the
At

page_text: signalling apparatus. In that case the lever should be so pivoted that it will
vibrate from side to side between the arms, and must be itself a permanent magnet
and incline by gravity to the like pole of the main magnet: The locking end may
be so arranged that it will engage with the notch by the inclination caused by
5 gravity, and when the main electro magnet is charged the end of the lever will be
repelled from that pole to which it was inclined by gravity, and then the rod will
be unlocked, but at all other times the rod and shunting apparatus moved thereby
will be locked. As the locking depends on the weakening of the main line current
it is plain that the locking mechanism is acted upon by the key as effectually as
by the shunting in of any of the telephones of the line. If it should be deemed
desirable therefore, as may some times happen at the central office, to lock all the
telephones of the line, it may be done by throwing open the key. The second part
of my Invention, including the signalling devices, has for its leading feature a loop
in which the bell magnet is located permanently connected with the main line,
with an important arrangement of shunting devices for short circuiting operated
by an electro magnet in the said main line. It consists also of certain improved
details of construction hereinafter fully set forth. In this part of my Invention
the magnets, bell, and working parts of the machine are mounted upon a metallic
frame, and are held by a screw passing through the frame. The bell magnet is in
a similar manner mounted upon the frame directly above the main magnet, and
the bell is mounted upon a stand directly over its magnet. The armature of the
main line magnet is supported upon pivots in the frame and carries a slender rod
or bar which operates the pawl and ratchet mechanism. The armature is mounted
upon standards by means of pivots, and carries a bell hammer adapted when the
armature is drawn up to the magnet to strike the bell. The main shunting devices
by means of which any instrument in the circuit may be brought into call at the
will of the operator at any other station are described in connection with the pawl
and ratchet mechanism. Upon the shaft. of this ratchet and concentric therewith
is a wheel, on the periphery of which is an insulated spot made by the insertion
of a piece of non conducting material. Bearing against the periphery of this wheel
is a light spring standard, the lower end of which is fixed to an insulated block
connected to the frame. This standard is in electric connection with the main
line, as is hereinafter fully explained. The pawl and ratchet mechanism is of an
impoved form, and is designed to obtain the same amount of movement of the
ratchet wheel with only one half of the movement of the armature, whereby
greater rapidity of action is gained and less battery power required. The
wheel is a ratchet wheel of ordinary form, but instead of the ordinary pawl
working to one side of the wheel I have provided two which work in
opposite directions, and thus obtain a movement of the wheel with the forward
as well as back movement of the armature. The pawls are pivoted in the rod or
bar, one above and the other below. The upper pawl is arranged longitudinally
to the notches or teeth on the upper edge of the wheel, and is formed with a plain
end adapted to fit against the faces of the teeth so as to push the wheel when the
standard is moved towards the wheel by the backward movement of the armature
to which it is attached. The lower pawl is tangent to the lower face of the wheel,
and is provided with a hook adapted to catch over the teeth of the ratchet wheel
and bear against their vertical faces, so as to draw upon said teeth and partially
turn the wheel when the armature carrying the bar is drawn up. It will be
understood from this construction that the pawls move simultaneously and in the
same direction but act alternatively and in opposite directions. While the upper pawl
s pushing the lower is slipping over a tooth into engagement with another, on which
t is free to act when the upper has reached the limit of its movement. When the
rinature is drawn up and the reverse motions of the pawls occur the lower pawl
raws upon the wheel, giving it a partial turn while the upper slipping over a
ooth in a manner described above in connection with the lower. In this action of
he pawls and ratchet wheel there is manifestly a movement of both pawls and
wheel, and the movement of the wheel both above and below serves equally to
+

page_text: bring the bearing face of the pawl toward the bearing face of the boon.
should be so adjusted that when the armature carrying the bar is drawn up the
One pawl or
pawls shall both be in contact with the radial faces of the teeth.
tooth is therefore always in contact with the radial face of a tooth or teeth, and
the wheel is turned and held against backward movement without any other 5
holding device. When the armature is drawn up the tendency of the wheel is to
advance more than a single tooth, and thus impair the accuracy of the instrument.
To prevent this I place a post directly under the pawl and cut away the edge of
such pawl above it.
On
fixed
This curved recess is so arranged in relation to the post and the teeth of 1
the ratchet wheel that when the armature falls back and advances the pawls
towards the wheel the lower pawl shall ride freely over the tooth, but when
the armature is drawn up the pawl is drawn back with the inclined part
approaching more nearly to the post, which prevents the pawl from moving far
enough downward to permit the tooth to pass over the hooked end thereof. It is
plain that the pawls must be held to the wheel with just sufficient force to maintain
contact. Any suitable spring may be employed for the purpose. A convenient
and simple arrangement is as follows:-The ends of the pawls extend a short
distance to the rear of their pivots and are curved outwardly so that a spring (one
end of which rests on the upper and one on the lower) presses both towards the
wheel. The armature of the main magnet is drawn back with the required force
by means of another spring, the tension of which is adjusted by a spring on a bar
to which it is connected, the spring or bar being drawn back by a set screw.
the shaft of the ratchet wheel and concentric therewith is placed a smaller metal
wheel in electrical connection with the frame. It is made smaller than the ratchet
wheel in order that the pawl working upon the periphery of the larger ratchet
wheel may gain in leverage, and thus more easily overcome the friction of a light
spring, the end of which presses against the periphery of the smaller wheel; when
thus pressed it brings the smaller wheel into the main line circuit except when one
end of the spring rests upon an insulating spot in said wheel; the spring
to and insulated upon a block attached to the frame, and is connected to the main
line wire. This spring in connection with the insulated spot upon the wheel
constitute the first shunting device in the main line, the operation of which is
explained hereinafter in connection with the general operation of the apparatus.
As an equivalent device the wheel may be provided with a notch instead of an
insulated spot, and the spring has a spur fitted to the notch. The spring in this
form, as in the other, is insulated on a block, but is not connected to the wire.
Connection with the wire is obtained through another spring, also insulated on the
block and connected to the main line wire. When the spur is in the notch there
is a space between the upper ends of the two springs, and the circuit is broken,
but it is closed when the spur rests on the periphery, and the first spring is
thereby forced back into contact with the second. This modification will operate
equally as well as the other, except that slightly more battery force is required to
move the spur of the notch. A second shunting device operated in connection
with the bell magnet consists of a spring fixed upon the insulating block and also
connected to the main line wire. The spring is placed on one side of the frame
The upper and free end rests upon an insulating block on the end of the armature
when said armature is thrown back. When however the armature of the bel
magnet is drawn up the spring following it moves to a metal stud (preferably of
After the spring
platinum) which is in electrical connection with the frame.
reaches the stud it remains in contact until removed by the return of the arinature
It will be understood therefore that the second shunt, being within the main line
wire and between the primary shunt and the connection of the bell loop with the
main line, establishes for an instant the circuit in the main line broken by the
contact of the first shunting spring with the insulating spot on the wheel. Bu
whether this be open or closed the connection of the loop including the bell magne
is permanently complete. The special operation of these parts are also set fort

page_text: fully in connection with the description of the operation of the whole. The
improved key mechanism will next be described. A defect occurs in the use of the
ordinary key in connection with apparatus of the class herein described. Uniformity
of actions in the signalling apparatus depends largely upon uniformity in the
pressure applied to the key which brings the parts into contact to make and break
connections. The difference between a firm positive pressure and a weak slight
touch is sufficient to impair the operations of the apparatus. Where the contact is.
obtained by direct pressure applied by the hand it will generally be more or less
variable. The object of this part of my Invention is to obtain a positive contact
uniform and certain under all circumstances. Within the frame at one end I pivot -
a lever by means of a screw, so that the drums project outside the frame and loosely
embrace a spring, so that a certain amount of movement of said spring will give
the necessary throw to the lever. The inner end of the lever is provided with a
friction wheel, and bears against the face of a spring standard. This standard is
formed with a sharp bend projecting towards the lever and in its path, so that
when the lever is pressed down by the spring the opposite end rises, the friction
roller runs up the lower incline, pressing the spring back until the wheel has passed
the apex of the bend, when the elasticity of the spring reacting upon the wheel
presses with the opposite or upper face of the incline and forces the lever upward,
completing the movement begun by the hand. All that is required is that it shall
press the key sufficiently to cause it to pass the bend in the standard. Less force
applied to the spring will not cause the lever to pass the bend and will not break
contact. Upon the lever is pivoted by the same pivot a loose plate. One end is
rounded on a curve struck from the centre of the pivot, and the other is provided
with two arms which are bent inward so as to enclose the inner end of the lever
but loosely so as to give a certain amount of play to the plate or to the lever within
the arms of the plate. There is a sleeve upon the pivot, on which the lever and
plate directly turn and which secures freedom of movement. On the outer or
rounded edge of the plate rests a spring which is insulated on the frame and is
connected to a section of the main line wire. The key mechanism being connected
to the frame when the insulated spring is in contact with the metallic part of the
rounded face of the plate the connection is made through the line.
This happens
when the key spring is raised, but when the key spring is depressed the contact
end of the lever rests on an insulating spot and the connection is broken. It will
be observed therefore that the contact which makes and break connection is
caused by the pressure of the spring against the rounded edge of the plate, and
that the last part of the movement of the lever which brings the insulating spot
under the contact end of the spring is effected by the reaction of the spring
standard. The contact if made at all must therefore always be precisely the same,
regardless of the amount of force applied to the spring, providing only that it shall
be sufficient to move the lever past the bend of the spring standard. The general
directions of the wires and other electrical connections is next described. Supposing
a given post to be in electrical connection with the positive pole of the battery the
direction of the current will be through the section of the main line which is con-
nected to one end of the coil of the main magnet. From the other end of said coil
a wire runs to the junction of two other wires. Of these the first is connected to
one end of the coil of the bell magnet, the other end of which is connected to the
frame. Through this (provided the connection of the second wire is broken) the
current passes by means of wires and a key to the post to which the other end of
the main line is attached. As before stated the second wire runs to the insulated
spring, which when in connection with the metallic face of the smaller of the two
wheels before described is in electrical connection with the frame and through that
with the main line. When the spring is on the insulated spot this connection is broken
and the current is forced upon this shorter circuit into the loop, which includes the
bell magnet. It will be readily understood that the insulating spot on the wheel is
arranged to correspond on each machine to the number of the station, and that the
wheel is turned by successive impulses through the line, each impulse turning the

page_text: ratchet the space of one tooth. The operator at any other station sending the proper
number of impulses brings the insulated spot of any given machine under the spring
and thus breaks the main line. This, as explained before, forces the current through
the loop and operates the bell armature, drawing it up, and with it the hammer,
against the bell. This movement as explained brings the spring into contact with
the stud and makes again the main line connection, thereby diverting the current for
an instant sufficiently from the loop to allow the bell magnet armature to fall back,
which breaks the connection in the main line and restores the current in the loop.
Thus the bell is rapidly rung as long as the spring rests on the insulated spot of the
wheel. The intervals of connection in the main line are not sufficient to work the
armature of the main line magnet. The connection of the loop with the main line
is never broken. The breaking of the connection on the wheel (which is the first
shunt) gives impulse to the bell magnet armature, and the rapid breaks at the
second shunt cause the bell to ring as long as the spring is on the insulated spot, in
fact until it is removed by the operator, but when the connection with the wheel is
closed the bell cannot be rung. A dial is provided over which the index finger on
the end of the ratchet wheel shaft moves and indicates the position of the insulating
spot. In the form of signal now described the loop which includes the bell magnet
A primary
is also permanently connected with or forms part of the main line.
electro magnet is included in the same line or circuit and adapted to operate an
escapement or lock mechanism to release a bell armature in combination with a
secondary electro magnet included in the loop from the main line, connection with
said loop being made and broken by means of the movement of the bell hammer in
striking, and of the armature to which said bell hammer is attached, whereby the
operator at a distant station is able to release the bell hammer connection at any
required station or point, establish a communication through the loop, and sound
To an electro
the signal without disturbance of any other signal in the circuit.
magnet located in the main circuit of the line is fitted an armature maintained in
proper position in relation to the magnet by light spring supports, which are
arranged to hold the said armature when at rest away from the magnet. In front
of the armature and mounted in standards is a rock shaft which carries a post.
The shaft is rocked by means of the post fixed thereon and connected to the
armature by a light bar. The amount of motion imparted to the escapement by
means of the armature is sufficient to cause it to move the escapement one notch at
each oscillation of the said armature. On the shaft of the escapement wheel is a
cam or stud adapted when the said shaft has been rotated a sufficient distance to
lift a stop bar so as to fall when not so lifted in rear of the second armature. This
second armature operates in connection with a second electro magnet which is
included in a loop from the main wire and is adapted to operate a bell mounted
over the second magnet. The apparatus may be used with an open circuit or with
a closed circuit and several instruments. When adapted to the closed circuit and
for any number of instruments in the same circuit the device for operating the bar
which dogs the bell armature is the same as has been described above. The magnet
which operates the escapement is included in the main circuit. The loop includes
the coil of the electro magnet for the bell. The wires of the loop return to nearly
the same point but leaving a space which is closed by a plate or bar held in contact
with the two branches of the main wires by means of a spring. When the plate is
in contact the main circuit is closed, and the current following the line of least
resistance passes through said main circuit and does not operate on the loop
sufficiently to ring the bell. When however this bar and plate is thrown
off the main direct line is interrupted and the loop is brought into the main
circuit so as to operate the bell magnet and ring the bell. The plate or bar is
operated by the spring and tail of the hammer. The armature rocks on a spring
standard from a pivotal point and when thrown forward by the bell magnet lifts or
springs the tail clear from the plate allowing it to complete the main circuit. This
cuts out the loop and lets the armature and bell hammer fall back opening the
main circuit and again.including the loop; this action is repeated automatically as

page_text: long as the hammer ceases to dog the armature. The form of the shunting devices
may be greatly varied provided only that the retraction of the armature carrying
the bell hammer opens the switch in the main circuit and includes the loop. On
the end of the shaft of the escapement wheel is an index finger moving over the
face of a numbered dial. The index finger moves with the shaft and may be set
for any number. Obviously the index finger may be turned on the shaft to any
number on the dial, and the cam is to be in proper position to lift the lever
as explained. Where there are several instruments in the same circuit these
indices are to be set on each machine for its proper number, and the operator.
at any station or point desiring to signal any other specified station, makes and
breaks the connection until the index finger of the dial of his own instrument
points to the number of the specified station, and then the rocking, on the shaft
of the segment wheel of that particular instrument will have lifted the stop lever
and released the armature of the bell magnet. The apparatus may be operated
either by a battery or a magneto electrical machine. Other devices may be
used instead of the escapement, though I consider the mechanism described
simple and convenient. Manifestly the shunting devices may be indefinitely
changed.
It should be noted that the device for lifting the stop bar which dogs the
armature of the bell should be so made as to operate on said bar quickly, since
all the instruments in the circuit will move simultaneously and at those set for
the lower numbers when the higher numbers are called the bar will be lifted
only for an instant. In that case only a single stroke at most can be sounded.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Philip Middleton Justice in the Great Seal Patent Office on the
16th August 1881.
PHILIP MIDDLETON JUSTICE, of 14, Southampton Buildings in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN TELEPHONIC APPARATUS AND
SIGNALS THEREFOR." A communication from abroad by Homer Rice Miller, of
South Framington, in the County of Middlesex, State of Massachusetts, United
States of America.
This Invention relates to electric speaking telephones and to signalling
mechanisms adapted to be used therewith. The first includes locking mechanisms
whereby the operator at any given station may lock out all the stations in the line
excepting his own and that with which he desires to communicate. The second
part includes an improved electric signal specially designed to be used in connection
with electric speaking telephones but also capable of independent use. The object
of the first part of my Invention is to secure privacy in telephonic communication
by the temporary exclusion of all other stations in the line excepting those
between which communication is held. This object has been partially and
imperfectly attained, or has been attempted by means of intricate mechanisms
difficult and impossible to be operated in practical work. This part of my Invention
is illustrated in Sheet 1 of the accompanying Drawings, to the particular parts of
which Sheet reference is had by letters in the following description. The shunting
mechanisms are represented as enclosed in a box which may serve as a base for
any suitable signalling apparatus. The main line wires are connected to ordinary
posts on the box or case A. at a, b, and from a extends to the helix of a small
electro magnet c swivelled in the upper part of the case. From the other end of
the helix the wire extends to the point 2 where it connects to the wire of the
telephone. At the point 3 it is however in connection with a spring joint d fixed
to the board partition M or otherwise insulated on the case, against which, as
shown in the Figure, rests a metallic switch lever e insulated on a point f; this
lever carries an insulating block g to which is attached a pronged plate i. From
the pivoted end of the lever e connection is made directly to the outer end b of the
main line by means of the wire 4, and when the lever c is in contact with the
At a suitable distance
point d, the circuit is through the parts just described.
above the lever when in the position shewn resting on stop x, is a point h similar
to d, connected by wire 5 to an insulated post 6. The remainder of the circuit
consists of the wire 7 connected to post 6, said wire passing through the induction
coil in the transmitter C, and continuing by wire 8 to post 9, and thence through
The circuit
the telephone to its connection to the part already described at post z.
is completed by the upward movement of the switch lever e, causing it to leave the
point d, and press upon an inclined spring end of point h. The same movement
of this lever moves also the pronged plate i. These points are bent at the ends,
and when the lever is down, as shown in the Figure, the ends bear only on the
point on partition M, but when the lever e is raised the prongs are moved, so that
the point of one rests upon the point K, and the other on a similar point forming
electrical connection between them. The point K is connected to the post 10 by
wire 11, and thence to one pole of the transmitter battery D. The wire from the
other pole passes through the induction coil in the transmitter, and thence to tho
post o, and reaches the point through the wire 12. It will be apparent from
the description given that circuit of the transmitter battery is made or broken by
the movement of the prongs, caused by the movement of the switch lever e, which
action, as is well understood, is necessary when the ordinary Le Clanche or a like
battery is used with the transmitter. It will be observed that the free end of the

page_text: lever c extends through a slot (indicated in dotted lines) in a vertical rod E. This
rod has a hook on the lower end, on which is hinged the telephone (B), and passes
through guides 0, 0, fixed to the frame. The rod is supported upon a spring p
which rests on the upper guide piece O, and bears underneath a pin in the end of
the rod. The slot in the rod E is wider than the switch bar, and allows the
spring p to lift the rod slightly without moving the lever. The tension of the
spring is such that the weight of the telephone B will depress the rod so as to
bring the notch J in said rod opposite the end of a bent lever S, the end of which
is fitted to engage with the notch, and lock the rod so that it cannot be pushed up.
The armature of the magnet t is attached to the upper end of the bent lever S, the
lever being so pivoted upon the arm in the case, that the armature when drawn up
shall throw the lower end of the lever out of connection with the notch, but when
not drawn up, the armature shall fall back by gravity and throw the end of s into
connection and lock the rod so that it cannot be raised. It will be understood
from this description of the parts that the magnet c at every station in the line is
in the main line circuit. Under ordinary conditions of the circuit, and when no
telephones are switched in, the effect of the current is to keep the armature t drawn
up and the rod unlocked. But when an operator at any given station is called,
he unhooks and shunts in his telephone. The great resistance of the telephone
then brought into the line so weakens the current that it will no longer act upon
the electro magnet c sufficiently to draw up the armature, and these armatures in
the whole circuit of the line will therefore fall back by their own gravity and lock
all the rods through which the shunting devices are operated, excepting that from
which the telephone has been removed. This happens of course at the station
which has been called, where the operator having removed the telephone, the rod E
is lifted by the spring p sufficiently to raise the notch above the catch without
disturbing the shunting lever e as that moves in the slot. The operator at this
station may push up the rod E and shunt in his telephone, and is thus able to
cominunicate with another station without liability of interruption by the operator
at any other station, or that the communication will be heard except at the two
stations in connection. The operation of the shunting devices is apparent from the
description heretofore given of these devices. By pushing up the rod E, the
shunting levere is lifted so that it leaves the point d, and is moved upon the
point h, on which it is held by friction. At the same time the points of the plate
are shifted so as to enclose the points and . This movement of the lever from
d to h shunts in the telephone, and that of plate i closes the circuit of the local
battery. A modification of the locking devices may be made by dispensing with
the electro magnet c, and extending the lever up between the arms of the main
magnet of the signalling apparatus. In that case the lever should be so pivoted
that it will vibrate from side to side between the arms, and must be itself a.
permanent inagnet, and incline by gravity to the like pole of the main magnet.
The locking end may be so arranged that it will engage with the notch by the
inclination caused by gravity, and when the main electro magnet is charged, the
end of the lever will be repelled from that pole to which it was inclined by gravity,
and then the rod will be unlocked, but at all other times the rod and shunting
apparatus moved thereby will be locked. As the locking depends on the
weakening of the main line current, it is plain that the locking mechanism is
acted upon by the key as effectually as by the shunting in any of the telephones
of the line. If it should be deemed desirable therefore, as may sometimes
happen at the central office to lock all the telephones of the line it may be done
by throwing open the key. The second part of my Invention, including the
signalling devices, has for its leading feature a loop in which the bell magnet is
located permanently, connected with the main line with an important arrangement
of shunting devices for short circuiting, operated by an electro magnet in the said.
main line. It, consists also of certain improved details of construction, hereinafter
fully set forth and particularly indicated in the claims. This part of my Invention
is shown in Sheets 2 and 3 of the Drawings: the machine is represented in

page_text: Fig. 1 as in perspective; Fig. 2 is a perspective view of the opposite side;
Fig. 3 is a side elevation with the parts in section; Figures 4 and 5 represent
the improved key mechanism detached; Figure 6 represents the main shunting
device, and Figure 7 a modification of the same. The magnets, bell, and working
parts of the machine are mounted upon a metallic frame A, and are held by a screw
passing through the frame, as shown at a. The bell magnet is in a similar manner
mounted upon the frame directly above the main magnet, and the bell is mounted
upon a stand directly over its magnet; the armature c of the main line magnet is
supported upon pivots in the frame, and carries a slender rod or bar d, which
operates the pawl and ratchet mechanism. The armature g is mounted upon
standards by means of pivots, and carries a bell hammer D, adapted when the
armature is drawn up to the magnet to strike the bell E. The main shunting
devices by means of which any instrument in the circuit may be brought into call
at the will of the operator at any other station are shown in connection with the
pawl and ratchet mechanism. Upon the shaft of this ratchet and concentric there-
with is a wheel k, upon the periphery of which there is an insulated spot 1
(Figures 3 and 6) made by the insertion of a piece of non conducting material.
Bearing against the periphery of this wheel is a light spring standard m, the lower
end of which is fixed to an insulated block n connected to the frame. This
standard m is in electric connection with the main line, as is hereinafter fully
explained. The pawl and ratchet mechanism is of an improved form, and is
designed to obtain the same amount of movement of the ratchet wheel with only
one half of the movement of the armature, whereby greater rapidity of action is
gained and less battery power required. The wheel is a ratchet wheel of ordinary
form, but instead of the ordinary pawl working to one side of the wheel, I have
provided two, which work in opposite directions, and thus obtain a movement of
the wheel with the forward as well as back movement of the armature. The wheel
revolves in the direction of the arrow (Fig. 3). The pawls are pivoted in the rod
or bar d, one above and the other below; the upper pawl e is arranged longi-
tudinally to the notches or teeth f on the upper edge of the wheel, and is formed
with a plain end adapted to fit against the faces of the teeth, so as to push the wheel
when the standard is moved towards the wheel by the backward movement of the
armature to which it is attached. The lower pawl e' is tangent to the lower face
of the wheel, and is provided with a hook adapted to catch over the teeth of the
ratchet wheel and bear against their vertical faces so as to draw upon said teeth,
and partially turn the wheel when the armature .carrying the bar d is drawn up.
It will be observed fram the construction shown that the pawls move simultaneously
and in the same direction, but act alternatively and in opposite directions.
the upper pawl is pushing the lower is slipping over a tooth into engagement
with another, which it is free to act when the upper has reached the limit of its
movement. When the armature is drawn up and the reverse motion of the pawls
occur, the lower pawl draws upon the wheel giving it a partial turn while the
upper is slipping over a tooth in the manner shown above in connection with the
lower. In this action of the pawls and ratchet wheel there is manifestly a move-
ment of both pawls and wheel, and the movement of the wheel both above and
below serves equally to bring the bearing face of the pawl toward the bearing face
of the tooth. The parts should be so adjusted that when the armature carrying
the bar d is drawn up the pawls shall both be in contact with the radial faces of
the teeth. One pawl or tooth is therefore always in contact with the radial face
of a tooth or teeth, and the wheel is turned and held against backward movement
without any other holding device. In operation, when the armature is drawn up,
if the movement of the wheel f should carry it in advance of the movement of the
pawls, and more than the space of a single tooth, the accuracy of the instrument
would be impaired. To prevent this I have set a post q directly under the pawl e
(Fig. 3), and cut away the edge of such pawl above it, as shown at q'. The curved
recess q is so arranged in relation to the post q and the teeth of the ratchet wheel,
that when the armature falls back and advances the pawls towards the wheel the
While

page_text: lower pawl e shall ride freely over the tooth, but when the armature is drawn up
the pawl is drawn back with the inclined part of q' approaching more nearly to
the post q, which prevents the pawl from moving far enough downward to permit
the tooth to pass over the hooked end thereof. It is plain that the pawls must be
held to the wheel with just sufficient force to maintain contact. Any suitable spring
may be employed for the purpose. A convenient and simple form of spring is shown
in Figure 3. The ends of the pawls extend a short distance to the rear of their pivots,
and are curved outwardly, so that the spring, one end of which rests on the upper
and one on the lower presses both towards the wheels. The armature of the main
magnet is drawn back with the required force by means of a spring i, the tension of
which is adjusted by a spring or bar I being drawn back by a set screw 4. On the
shaft of the ratchet wheel and concentric therewith is placed a smaller metal wheel /
in electrical connection with the frame; it is made sinaller than the ratchet wheel
in order that the pawls e, e¹, working upon the periphery of the larger ratchet
wheel may gain in leverage and thus more casily overcome the friction of the
light spring m, the end of which presses against the periphery of the wheel k;
when thus pressed it brings the wheel k into the main line circuit except when one
end of the spring m rests upon an insulating spot 1 (Fig. 3). The spring m is
fixed to and insulated upon a block n attached to the frame, and is connected to
the main line wire 6. This spring m, in connection with the insulated spot upon
the wheel, constitute the first shunting device in the main line, the operation of
which is explained hereinafter in connection with the general operation of the
apparatus. The wheel is represented detached in Fig. 6. An equivalent device
is shewn in Fig. 7, in which the wheel is provided with a notch instead of
insulated spot, and the spring m has a spur fitted to the notch. The spring m
in this form as in the other is insulated on a block n, but it is not connected to
the wire. Connection with the wire is obtained through spring m¹ also insulated
on block n, and connected to the main line wire 6. When the spur is in the notch
there is a space between the upper ends of m and m³, and the circuit is broken,
but closed when the spur rests on the periphery, and m is thereby forced back
into contact with ml. This modification will operate equally as well as the other,
except that slightly more battery force is required to move the spur out of the
notch. A second shunting device operated in connection with the bell magnet
consists of a spring / fixed upon the insulating block n, and also connected to the
main line wire 6. The spring is placed on one side of the frame, as shown more
clearly in Figure 1. The upper and free end of it rests upon an insulating block n'
on the end of the armature, when said armature is thrown back. When however
the armature of the bell magnet is drawn up the spring following it moves to the
metal stud (preferably of platinum), which is in electrical connection with the
frame. After the spring / reaches the stud it remains in contact until removed by
the return of the armature. It will be observed therefore that the second shunt
being within the main line wire, and between the primary shunt and the connection
of the bell loop with the main line establishes for an instant the circuit in the
main line broken by the contact of the first shunting spring with the insulating
spot on the wheel. But whether this be open or closed the connection of the
loop, including the bell magnet, is permanently complete. The special operation of
these parts are also set forth fully in connection with the description of the
operation of the whole. The improved key mechanism, shown detached in
Figures 4 and 5, is represented in part in Figure 1, the ends of the lever projecting
for engagement with the spring. The same is shown in connection with Figure 3,
with the wires attached, the parts however being moved out of place for con-
venience of illustration. A defect occurs in the use of the ordinary key in connection
with apparatus of the class herein described. Uniformity of action in the signalling
apparatus depends largely upon uniformity in the pressure applied to the key
which brings the parts into contact to make and break connections. The difference
between a firm positive pressure and a weak slight touch is sufficient to impair the
operations of the apparatus. Where the contact is obtained by direct pressure

page_text: applied by the hand it will generally be more or less variable. The object of this
part of my Invention is to obtain a positive contact uniform and certain under all
circumstances. Within the frame at one end I pivot a lever G by means of a
screw S, so that the drums t, t, project outside the frame, and loosely embrace the
spring F, so that a certain amount of movement of said spring will give the
necessary throw to the lever. The inner end of lever G is provided with a friction
This standard is formed
wheel, and bears against the face of a spring standard H.
with a sharp bend projecting towards the lever and in its path, so that when the
lever is pressed down by the spring F the opposite end rises, the friction roller
runs up the lower incline, pressing the spring back until the wheel has passed the
apex of the bend, when the elasticity of the spring reacting upon the wheel presses
with the opposite or upper face of the incline, and forces the lever upward, coin-
pleting the movement begun by the band. All that is required is that it shall
press the key sufficiently to cause it to pass the bend in the standard. Less force
applied to the spring will not cause the lever to pass the bend, and will not break
contact. Upon the lever G is pivoted by the same pivot S a loose plate J. One
end is rounded on a curve struck from the centre of the pivot, and the other is
provided with two arms u, u, which are bent inward so as to enclose the inner end
of the lever G, but loosely, as shown at Figure 4, to give a certain amount of play
to the plate or to the lever within the arins of the plate. There is a sleeve upon
the pivot S on which the lever and plate directly turn, and which secures freedom
of movement. On the outer or rounded end of the plate J rests a spring v,
which is insulated on the frame, and is connected to section 11 of the main line
wire. The key mechanism being connected to the frame when the insulated
spring is in contact with the metallic part of the rounded face of plate J,
the connection is made through the line. This happens when the key spring F
is raised, as shown in full lines in Figure 4. But when the key spring is
depressed as shown in dotted lines, same Figure, the contact end of lever v rests
It will be observed
on an insulating spot and the connection is broken.
therefore that the contact which makes and breaks connection is caused by the
pressure of the spring v against the rounded edge of plate J, and that the last part
of the movement of the lever which brings the insulating spot v under the contact
end of the spring vis effected by the reaction of the spring standard H. The
contact, if made at all, must therefore always be precisely the same, regardless of
the amount of force applied to the spring F, providing only that it shall be
sufficient to move the lever G past the bend of the spring standard. The general
directions of the wires and other electrical connections is shown in Figure 3.
Supposing the post K to be in electrical connection with the positive pole of the
battery, the direction of the current will be through section 5 of the main line,
which section is connected to one end of the coil of the main magnet. From the
other end of the said coil the wire 7 runs to the junction of wires 8 and 6, of these
8 is connected to one end of the coil of the bell magnet, the other end of which is
connected by the wire 9 to the frame. Through this (provided the connection of
wire 6 is broken) the current passes to wires 10 through the key and wire'll to
As before stated,
post at which the other end of the main line is attached.
wire 6, which is a continuation of 7, runs to the insulated spring m, which,
when in connection with the metallic face of the wheel, is in electrical connection
with the frame and through that with the wire 10 and main line. When spring m
is on the insulated spot 1, this connection is broken and the current is forced from
this shorter circuit into the loop which includes the bell magnet. It will be readily
understood that the insulating spot on the wheel is arranged to correspond on each
machine to the number of the station, and that the wheel is turned by successive
impulses through the line, each impulse turning the ratchet f the space of one
tooth. The operator at any other station sending the proper number of impulses
brings the insulated spot of any given machine under the spring m and thus
breaks the main line. This, as explained before, forces the current through the
loop and operates the bell armature, drawing it up, and with it the hammer, against

page_text: the bell. This movement, as explained, brings the spring into contact with
the stud p and makes again the main line connection, thereby diverting the current
for an instant sufficiently from the loop to allow the bell magnet armature to fall
back, which breaks the connection of hand p in the main line, and restores
the current in the loop. Thus the bell is rapidly rung as long as the spring m
rests on the insulated spot 1 of the wheel . The intervals of connection in the
main line between h and p are not sufficient to work the armature of the main line
magnet. The connection of the loop with the main line is never broken. The
breaking of the connection at 1 on wheel (which is the first shunt) gives impulse
to the bell magnet armature, and the rapid breaks at the second shunt cause the
bell to ring as long as spring m is on the insulated spot, in fact, until it is
removed by the operator; but when the connection with the wheel is closed the
bell cannot be rung.
A dial is provided over which the index finger on the end of
the ratchet wheel shaft moves and indicates the position of the insulating spot. In
the form of signal shown in Sheets 4 and 5, the loop which includes the bell
magnet is also permanently connected with or forms part of the main line. The
Drawing shows a primary electro magnet included in the same line or circuit, and
adapted to operate an escapement or lock mechanism, to release a bell armature in
combination with a secondary electro magnet included in the loop from the main
line; connection with said loop being made and broken by means of the movement
of the bell hammer in striking, and of the armature to which said bell hammer is
attached, whereby the operator at a distant station is able to release the bell
hammer connection at any required station or point, establish a communication
through the loop and round the signal without disturbance of any other signal in
the circuit. The Drawing shows further certain details of construction which are
fully set forth hereinafter and are illustrated in the accompanying Drawings,
Sheets 4 and 5, in which Figure 1 is a plan view of the instrument, adapted to a
closed circuit; Figure 2 is a side view, partly in section; Figures 3 and 5 arc
detached views of the shunting devices; Figure 4 is a diagram of the circuit
including several instruments. In the Figures of this Drawing A, A represents an
electro inagnet located in the main circuit of the line; fitted to this is an
armature a, maintained in proper position in relation to the magnet by light
spring supports which are arranged to hold the said armature when at rest away
from the inagnet. In front of the armature and mounted in standards b, b, is a
rock shaft C which carries a post d. The shaft C is rocked by means of the shaft
post fixed thereon and connected to the armature by a light bar c. The amount of
motion imparted to the escapement by means of the armature is sufficient to
cause it to move the escapement wheel fone notch at each oscillation
of the said armature. On the shaft of the escapement wheel is a cam or
stud g, adapted when the said shaft has been rotated a sufficient distance
to lift a stop bar h so as to fall when not so lifted in rear of the second
armature i This second armature operates in connection with a second electro
magnet B, which is included in a loop from the main wire, and is adapted to
operate a bell B represented as mounted over the second magnet. The apparatus
may be used with an open circuit and several instruments. In Figures 1 and 2
is shown the apparatus adapted to the closed circuit, and for any number of instru-
ments in the same circuit. In this form the devices for operating the bar which
dogs the bell armature have been described above, and are shown in Figs. 1 and 2.
The shunting devices are shown more clearly in Figures 3 and 5. The magnet
which operates the escapement is included in the main circuit 5, 5, (shown in dotted
lines). The loop which includes the coil of the electro magnet for the bell is
located at 6. The wires returning to the same point, but leaving a space (shown
more clearly in Figure 5) which is closed by a plate or bar S held in contact
with the two branches of the main wires 7, 7, by means of a spring t. When the
plate is in contact at 7, 7, the main circuit is closed and the current following the
line of least resistance passes through' said main circuit and does not operato on the
loop sufficiently to ring the bell. When however this bar and plate is thrown off

page_text: The
from the points 7, 7, the main direct line is interrupted and the loop is brought
into the main circuit so as to operate the bell magnet and ring the bell.
plate or bar is operated by the spring and tail n of the hammer. The armature rocks
on the spring standards K from a pivotal point, and when thrown forward by the
bell magnet lifts or springs the tail clear from the plate, allowing it to touch at 7, 7,
and complete the main circuit. This cuts out the loop and lets the armature and
bell hammer fall back, opening the main circuit and again including the loop. This
action is repeated automatically as long as the hammer ceases to dog the armature.
The form of the shunting devices may be greatly varied provided only that the
retraction of the armature carrying the bell hammer, opening the switch in the
main circuit, and includes the loop. On the end of the shaft of the escapement
wheel is an index finger P moving over the face of a numbered dial r. The index
finger moves with the shaft, and may be set for any number. Obviously the index
finger may be turned on the shaft to any number on the dial, and the cam is to be
in proper position to lift the lever as explained. Where there are several instru-
ments in the same circuit these indexes are to be set on each machine for its
proper number and the operator at any station or point desiring to signal any
other specified station makes and breaks the connection until the index finger of
the dial of his own instrument points to the number of the specified station, and
then the rocking on the shaft of the segment wheel of that particular instrument
will have lifted the stop lever and released the armature of the bell magnet. The
apparatus may be operated either by a battery or a magneto electrical machine.
Other devices may be used instead of the escapement, though I consider the
mechanism described simple and convenient. Manifestly the shunting devices may
be indefinitely changed. It should be noticed that the device for lifting the stop
bar which dogs the armature of the bell should be so made as to operate on said
bar quickly, since all the instruments in the circuit will move simultaneously and
at those set for the lower numbers; when the higher numbers are called the bar
will be lifted only for an instant. In that case only a single stroke at most can be
sounded.
Having thus described my Invention, what I claim is,—
1. In combination with the shunting mechanisms a series of telephones in a
circuit, locking mechanisms substantially as described, and electro magnets, said
locking mechanisms being operated through the magnets by the weakening of the
current when any telephone is shunted in, substantially as set forth.
2. In combination with the shunting mechanisms of the series of telephones of
a circuit, locking device, and electro magnets in the main line operating to hold
said lever in unlocking position only when no telephone is in the circuit, said
locking lever being combined also with mechanisms substantially as described,
whereby the unlocking of any one of the telephones prevents the station of that
instrument from being locked out, as set forth.
3. The combination with an electro magnet situated in the main line of a series
of telephones of the lever e, notch rod E, provided with a hook at its lower end
and with spring at the upper, said lever being connected to the shunting devices,
substantially as described in reference to Sheet I. of the Drawings and for the
purposes set forth.
4. The combination with the lever e, locking devices and rod E, of the points d
and and connecting wires, substantially as described in reference to Sheet I. of
the Drawings and for the purposes set forth.
5. The combination with the lever e, rod E, and locking devices, of insulated
pronged plate i, points and l, and battery connections, substantially as described
in reference to Sheet I. of the Drawings and for the purposes set forth.
6. An electrical signal consisting of an electro magnet situated in the main line
circuit and adapted to use any shunting device in the line by predetermined
movements of the key in combination with a second electro magnet situated in a
continuous loop permanently connected to the main line, and with a second
shunting device in the main line operated by the bell magnet armature, and

page_text: adapted to make and break connections in the main line, whereby the bell is made
to ring continuously until the first shunting device is operated, substantially as
described and for the purposes set forth.
7. In an electrical signalling apparatus the combination of the pivoted key lever,
a pin adapted to resist the first and to accelerate the latter part of the movement
of said key lever, of a plate having insulated spot thereon and moved by said key
lever, and of a spring connection bearing upon the face of said plate, all as described
in reference to Sheet 3 of the Drawings and for the purposes set forth.
8. The combination of the lever G, plate J, having insulated spot and spring
standard H, and mechanism for operating the lever, substantially as described in
reference to Sheet 3 of the Drawings, and for the purposes set forth.
9. An electric signal consisting of an electro magnet situated in the main line
or circuit, and adapted to operate mechanism to dog or release the armature of a
second clectro magnet in combination with such second magnet situated in a loop
of the said main line, and also in combination with shunting devices in said loop,
operated by the notion of the bell hammer or arinature, whereby any given bell
may be rung continuously at pleasure, as set forth.
10. In an electric signal the combination of the electro magnet A, A, its
armature connected to the escapement, and the escapement wheel with the cam or
lug on the shaft of said wheel, and the bell armature of said electro magnet included
in the loop, as described in reference to Sheet 4 of the Drawings, and for the
purposes set forth.
In witness whereof, I, the said Philip Middleton Justice, have hereunto set
my hand and seal, this Fifteenth day of August, in the year of our Lord
One thousand eight hundred and eighty one.
Witness,
LEOPOLD MORITZ,
14, Southampton Buildings,
Chancery
W.C.
Lane,
PHILIP M. JUSTICE. (L.S.)