IMPROVEMENTS AND RELATING ΤΟ Southampton Buildings, London, APPARATUS TO BE USED IN TELEPHONIC SYSTEMS FOR PUTTING ANY OF THE INSTRUMENTS CONNECTED WITH A CENTRAL STATION INTO COMMUNICATION WITH EACH OTHER
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the Office
of the Commissioners of Patents on the 21st April 1883. Communicated to
him from abroad by HT Cedergren and L. M. Ericsson both of Stockholm in
the Kingdom of Sweden
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
IN
"IMPROVEMENTS
AND RELATING ΤΟ
Southampton Buildings, London,
APPARATUS TO BE USED IN TELEPHONIC SYSTEMS FOR PUTTING ANY OF THE
INSTRUMENTS CONNECTED WITH A CENTRAL STATION INTO COMMUNICATION WITH
EACH OTHER [a communication to him from abroad by H T Cedergren and L. M.
Ericsson both of Stockholm in the Kingdom of Sweden]
"
This invention relates to telephonic apparatus:
The object of the said invention is to enable any of a number of telephonic
instruments in a circuit or any instrument of the telephonic system not situated
within the same circuit to be put, by means of a single conducting wire, in direct
communication with the central station.
According to the said invention I provide one or more instruments at the central
station for the purpose of causing electric impulses, and one connecting instrument
within each circuit.
The apparatus for causing electric impulses is enclosed in a box and a cylindrical
case placed on the top of the said box. An upright shaft, is provided the lower
extremity of which is pivotted in a suitable frame the upper extremity passing
through the said frame and a dial above the latter of which it has a crank or
handle. On the said shaft is secured a toothed wheel and a second wheel, the
circumference of which is provided with steps at certain interspaces and of certain
length. Besides the said wheels there are movably mounted on the shaft two
connected wheels, that is to say a ratchet wheel, in which catches a pawl secured
to the second wheel and a third toothed wheel. The said toothed wheel gears with
a pinion on a second shaft from which the motion is, by means of gearing,
transferred to a third shaft to which are secured two wings acting to retard.
the motion of the apparatus. Around the first shaft is secured a spring box, the

page_text: spring of which tends to turn the shaft in a certain direction. The communicator
consists of a lever arm provided with a knob and projecting from a fourth shaft
supported at both ends. At the sides of the said lever arm project two contact
pieces which, by a spiral spring, are pressed upwards against the contact screws.
The said contact pieces are insulated from the fourth shaft and are brought into
conducting connection with the electrodes of a battery
Two levers are provided having contact pieces, which, when the levers are turned
outwards are brought into contact with adjustable contact screws. The said two
levers which are drawn inwards against a central support of springs, are placed,
one at the side of, and a little lower than the second wheel, and the other at the
opposite side of the first toothed wheel. One of the said levers has a hook which,
by means of a spiral spring, is pressed against a pin. In the same manner the
hook of the second lever is arranged. An elastic arm on which is a projection,
retains the crank or handle when wanted, and prevents it from turning round.
When the said elastic arm is pressed backwards the crank is disengaged so that the
first shaft is turned round under the action of the spiral spring. The hook on the
first arm will then glide up a plane in the circumeference of the second wheel, which
plane is greater than the others, and by the said hook encountering a pin it cannot
be turned but brings, on the contrary, the said first lever outwards so that one of
the contact pieces comes in contact with a screw and thus closes the circuit so that
a current will pass along the line and last as long as the hook is passing the plane.
At the terminus of the line the current passes into the earth after having passed
through the coupling apparatus. From the earth contact the circuit is completed
through a contact piecé and from this to the zinc electrode of the battery. When
the central shaft is revolving a pawl catches in the teeth of the ratchet wheel and
puts thus the third shaft in motion which causes the wings to lessen the speed of
the movable parts, so that a certain moment of time elapses before the hook has
glided across the plane. This plane is greater than those on the second wheel, as,
in beginning, a current of greater duration is required in order to overcome the
momentum of the movable parts. When the plane has got below the hook causing
the latter to fall into the next following slot, the contact is interrupted, and in lieu
of this a tooth of the first toothed wheel moves forward passing beneath the hook
of the second lever whereby this latter is pushed outwards so that another bow or
contact spring comes into contact with a screw, whereby the conductor is connected
with the earth with the view of discharging the secondary current. The next
impulsion is emitted in the line when the hook has glided upon the next plane of
the second wheel. By this apparatus currents at certain intervals and of certain
duration are consequently caused by the hook of the first lever alternately rising
on the plane of the second wheel and falling into the slots and after each impulse
a discharge can take place by the hook at the end of the second lever moving onto
the teeth of the first toothed wheel. Meanwhile the crank has moved on the dial
which is divided into as many divisions (in which numbers are marked) as the
second wheel contains planes. The box enclosing the apparatus is at the top edge
provided with a number of movable hooks (one for each number.) In order to
cause a certain number of impulses on the line it is only necessary to adjust the
hook corresponding with the figure in the division when the crank, after having
been disengaged from a retaining arm, turns until it stops against the erected hook.
The crank is brought back to its original position by manual power, in which case
the pawl slides over the teeth of the ratchet wheel, so that the train of gear wheels
will not be brought into motion. The spiral spring is relieved when the crank is
turned back. The hooks of the levers are then turned in the opposite direction but
will only strain their spiral springs and thus effect no displacement of the said
levers, from which it follows that no contacts are obtained.
In order to cause in the line a current in the an opposite direction by means of
this apparatus, it is only necessary to depress a communicator, when the contact
pieces are brought into contact with pieces placed beneath them.
*The connecting apparatus is enclosed in a box and consists of a dial, in the front

page_text: of which moves a band secured on a shaft acted upon by a spiral spring which
tends to keep the hand pressed against a pin on the dial. The circumference of
the dial is divided into as many divisions as the circuit contains telephonic
apparatuses. Behind the dial is secured on the said shaft a ratchet wheel in
which a hook at the end of a link bar catches. This link bar is connected with;
one arm of an angular lever pivoted at its point, and the second arm of which
forms the armature of an electro-magnet of about 80 Siemens unit resistance.
A lever is provided which at one end is pivotted and at the other end lies against
the ratchet wheel and serves as a pawl thereof. This lever is suitably connected.
with the armature of a second electro-magnet also of about 80 S. U. resistance.
The dial is at its surface provided with a number of contacts, with which the
hand by means of a slight spring secured at its under side comes in contact when
the hand is turned in different positions, and which contacts are put in electrical
connection with the instruments in the circuit. The apparatus comprises further
a system of magnetic needles composed of three magnets which in their longitudinal,
direction can be encircled by a current passing from the first named apparatus at
the central station and through a bobbin surrounding the central magnet. The
upper magnet has at the top a small wheel or roller, which when the magnets are
deviating to one or other side, come in contact with and raise one end of two levers,
the other end of which will then fall and come in contact with one of the contact
pieces. A magnet is arranged to fix the position of rest of the magnetic needles.
t
The crank having been disengaged in the apparatus at the central station a
current will be caused as hereinbefore described which enters the connecting.
apparatus through the line wire passing round the magnets and to the hand; it
further passes to a pin and from this to the earth after having previously passed
through a bobbin of about 600 S. U. resistance. The magnetic needles deviate
then in one direction and raise a lever which then causes contact with a tongue
whereby a shunt is obtained so that the greater part of the current, in lieu of.
passing through the resistance coil to the earth, passes through one of the electro-
magnets, a lever and the magnetic needle, and thence to the earth. On this
occasion the said magnet attracts its armature whereby the link bar turns the
ratchet wheel and its shaft so that the hand on the dial comes into contact with
the next point of contact on the dial. A bar prevents the hand from being
returned by the spring. The next following discharge of the current through the
apparatus at the central station causes one of the electro magnets to drop its
armature. The next impulsion arrives through the line, before the magnetic
needle has had time to interrupt the contact and then the operation just now
described is repeated whereby the hand is brought over to the next contact. Thus
it continues until the crank of the apparatus at the central station stops against.
the erected hook. When the current arrives at the connecting apparatus a small
portion of it can no doubt pass from the contact at the dial to the signal bell of
that telephonic apparatus within the circuit which corresponds with this contact
but the conducting wire of this causes a resistance of about 100 S. U., and the
armature of the bells can moreover be adjusted. Thus it will be evident that a
person can from the central station by means of these apparatuses put himself or
other subscribers in direct connection with any telephone within the circuit.
Suppose for instance that an apparatus has been put in connection with the
central station. When then the usual bell signal is given, the current passes
through the line and round the magnet which by reason of the impulses rapidly
succeeding each other in opposite direction is not able to effect any contact.
Consequently the current goes to the hand and through this over to the bell
of the apparatus which then is brought in operation, and thence to the earth.
The subscriber called on by this signal can then speak with the caller.
the conversation is finished and the final signal given the communicator on the
central station apparatus is depressed, when a current is passed in an opposite
direction. This makes then the magnet deviate in the opposite direction and
brings the needle to another contact. The current then passes through the other
When

page_text: electro magnet and the needle to the earth. Thereby the armature will be
attracted which in its order lifts a rack so that this disengages the link bar when
the shaft with its hand is brought back into its former, position by means of the
spiral spring. When the hand lies against, a pin the central station can be called
upon from any apparatus within the circuit, if only a knob at the apparatus be
depressed, when the current passes from the battery of the said apparatus through
the wire to the hand and from hence round the magnet to the central station. .
⋅
When any apparatus within the circuit is coupled together with the central
station, this cannot be called upon from any other apparatus neither can the
conversation be listened to because the hand is then resting on a certain point of
contact on the dial and the wire consequently put out of connection with the line.
This is made evident to the. caller by the circumstance that no current passes the
bell apparatus of his telephone which consequently cannot ring.
.
In a modification of this invention the magnetic needle is substituted by an
armature pivotted between the poles of a magnet. This armature is surrounded by
the wire arriving from the line, which wire thence proceeds to the hand. The
pivotted armature is provided with a bar the lower extremity of which supports a
weight, tending to keep the bar vertically. When a current passes the armature
this turns in consequence of the influence of the magnet whereby one of the contact
springs attached to the top of the bar comes in contact with two points whereby
the current from the line in one case passes the electro-magnet and the bar and
thence to the earth .or. through the other electro magnet and the bar to the earth
and creates then the same effects as the corresponding parts of the apparatus. In
lieu of the armature a polarized relay with its armature might also be used in order
to effect contact in one or other direction.
It is evident that the above described connecting apparatus would work if the
apparatus placed at the central station were to be substituted by a common
communicator or any otherwise constructed apparatus provided a certain number.
of currents of certain duration and at certain intervals could thereby be passed to
the coupling apparatus and likewise a current in opposite direction, and that a
discharge of the line could take place after each current.
A modification of the coupling apparatus may be arranged so that the contacts
of the dial are arranged in a straight line in lieu of in a circle and so that above
these contacts moves a plate or such like which is brought to and from thereby so
that the working magnets act upon a rack. Where the line between the central
station and the coupling apparatus is long the electro magnets can be substituted by.
relays. The current in the coupling apparatus when no telephonic apparatus is
connected with the line is conducted to the earth and if required is provided with
a resistance of about 600 S. U. in lieu of being conducted to the earth.