Improvements in Magneto-electric Telephonic Apparatus.
Year: 1890

page_text: Date of Application, 21st Nov., 1890
Complete Specification Left, 17th June, 1891-Accepted, 18th July, 1891
PROVISIONAL SPECIFICATION.
Improvements in Magneto-electric Telephonic Apparatus.
I HARRY THOMAS OGILVIE FRASER of 109 Farringdon Road in the City of
London Mechanical Engineer do hereby declare the nature of this invention to be
as follows:-
My invention has for its object to provide an efficient and economical magneto-
electric telephonic apparatus wherein the same magnets serve for the bell and
the receiver and transmitter coils in each instrument. For this purpose I make
extensions from or connected with the respective poles of the magnets used for
giving the current for sounding the bell and upon one of these I mount the trans-
mitter coils and upon the other the receiver coils so that the said projections
constitute the cores of the coils and are magnetized by the said magnets I also
provide a handle for operating the generating coil or armature for ringing the bell
at the distant station by a to and fro movement of the handle which handle is
pointed to the armature axis and carries the hammer for the bell at the instrument
where it is situated. When the handle is turned into position for operating the
armature the hammer is at the same time turned away from the bell on the same
instrument. Under the action of a spring or the like the handle returns to its
normal position after use. In order that my invention may be well understood T
will describe an arrangement according thereto without however confining myself to
the precise details which I shall describe. The transmitter and receiver may be
made alike each consisting of an electro-magnet within a shallow box or recess (say
in the top of the case of the instrument) and having a diaphragm clamped imme-
diately over it and with a mouth piece or tube attached as usual. The transmitter
is firmly attached to one pole of the generating magnet by means of the core of its
electro-magnet, the receiver being attached to the opposite pole of the generating
magnet in a similar manner so that the two cores are magnetized by the said magnets.
Between the poles of the generating magnets is centered the generator coil or
armature to one end of the axis of which is centered a lever one end of which is
provided with a handle projecting to outside the case of the instrument through a
slot which is formed of a curved and a recessed part in which latter the handle
normally engages.
Secured to the said lever is a flexible arm carrying the bell hammer. The lever
is retained by a spring in its normal position so that its handle lies in the said
recessed part of the slot and the hammer is in proximity to the bells. When the
handle is depressed it leaves its recess and enters the curved part of the slot and
the hammer moves away froin the bell and then the handle and lever and the axis
of the armature together with the armature can be moved to and fro to generate the
current for ringing the bell at the distant station. At the other end of the axis of the
armature is an insulated contact which moves with the armature and pressing against
this insulated contact is a contact spring. The usual switch hook may be used so
that when the receiver is hung in place it causes the completion of the ringing
circuit and when removed it cuts out the ringing circuit and puts in the transmitting
and receiving circuit. In the arrangement described the lever with its handle has two
motions an oscillating and a rocking one. If the handle be pressed down the lever
will be turned on its centre so as to withdraw the bell hammer from proximity to the
bell as aforesaid and as the handle has now left the recess part of the slot and
entered the curved part it can be moved to and fro as hereinbefore described to
impart the same motion to the generating coil or armature which by cutting the
magnetic field alternately thereby transmits a current and rings the bell at the
distant station. When the handle is released it will automatically return to its

page_text: normal position the handle entering the aforesaid recess and the bell hammer taking
up its position in proximity to the bell and thereby it is in position to receive a call
or ring. This may be accomplished by means of the aforesaid spring on the lever
and by means of a spring or springs pressing against the lever or a projection there-
from to bring it into the central position so as to enter the said recess.
In place of using a handle to move the generator coil or armature to and from I
may use a handle to rotate it.
Dated 21st day of November 1890.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Magneto-electric Telephonic Apparatus.
I HARRY THOMAS OGILVIE FRASER of 109 Farringdon Road in the City of
London Mechanical Engineer do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
My invention has for its object to provide an efficient and economical magneto-
electric telephonic apparatus wherein the same magnets serve for the bell, the
receiver, and the transmitter coils in each instrument. For this purpose I make
extensions from, or connected with, the respective poles of the magnets used for
giving the current for sounding the bell and upon one of these I mount the trans-
mitter coils and upon the other the receiver coils so that the said projections consti-
tute the cores of the coils and are magnetized by the said magnets I also provide a
handle or equivalent device for operating the generating armature for ringing the
bell at the distant station by giving to the handle or the like a to and fro inovenient.
The handle is jointed to the armature axis and carries the hammer for the bell at
the instrument where it is situated and so arranged that when the handle is turned
into position for operating the armature the hammer is at the same time turneil
away from the bell on the same instrument. Under the action of a spring or the
like the handle returns to its normal position after use.
In order that my invention may be well understood I will describe with reference
to the accompanying drawings an arrangement of apparatus according thereto
without however confining myself to the precise details which I shall describe.
and
Figures 1 and 2 are vertical sections at right angles to each other of the apparatus
Figure 3 illustrates an arrangement for oscillating the generating arinature.
Referring to Figures 1 and 2 the transmitter Å and receiver B are made alike
each consisting of an electro-magnet an² contained within a shallow box or recess b
in the top of the case C of the apparatus and having a diaphragın & clamped over it.
The transmitter A is fitted with an ordinary mouth piece è and the receiver is fitted
with tubes and ear pieces as usual. The transmitter is firmly magnetically
attached to one pole D of the generating magnets E by means of the core 9 of its
electro-magueta, the receiver being attached to the opposite pole D³ of the
generating inagnet in a similar manner by the core of its clectro-magiiet a² so that
the two cores and g² are magnetised by the magets B: Between the poles D D³
of the generating magnets is centered the generator coil or armature F to one end
of the axis of which is centered a lever G, provided with a handle II which projects
through a slot I to outside the case C of the instrument which slot is dirved ind
has a recessed part at K in which the handle normally engages.
Secured to the said lever G is a flexible arm L carrying the bell hamilier M.
The lever G is retained by a spring n in its normal position so that the handle H
lies in the recessed part K of the slot I and the Ranimer M is in proximity to the
bell gongs N.
When the handle H is depressed the lever G turns on its centre /
and the handle leaves the recess K and enters the curved part of the slot I. The

page_text: hammer M is thus moved out of the range of the gongs N so that the handle
and lever together with the armature can be oscillated or moved to and fro to
generate the current for ringing the bell at the distant station. At the end of the
axis of the armature opposite that carrying the lever G. is an insulated contact p.
which moves with the armature and pressing against this insulated contact is a
contact springforming part of the circuit as usual. The usual switch hook may
be used so that when the receiver earpieces are hung in place they cause the
completion of the ringing circuit and when removed they cut out the ringing circuit
and put in the transmitting and receiving circuit in the usual manner. By moving
the handle to and fro in the curved slot I as hereinbefore described and thus
imparting the oscillating motion to the generating armature and cutting the
magnetic field at right angles a current is transmitted to, and the bell rung at, the
distant station-When the handle is released it will be automatically returned to
its normal position under the action of springs pressing on the projections s
from the axis L. of the lever G. so as to bring the lever with its handle
opposite the recess K so that the spring n then forces the handle into the said recess.
The bell hammer M being then in proximity to the gongs and in position to
strike them when a current from a distant station enters the armature, the
oscillations thereof will be sufficient to sound the bell.
Figure 3 shews an arrangement for giving the oscillating movement to the
armature by means of a cam groove m formed in a tubular shaft or sleeve t. fitted
to slide longitudinally on the spindle or shaft of the armature in which groove a
pin or projection on the shaft cnters, so that when the sleeve t is moved longi-
tudinally, it imparts the necessary oscillating motions to the armature. The sleeve
is prevented from turning with the armature by means of a spline or rib 2 on the
sleeve fitting a notch or groove in the bushed opening u in the casing C through
which the sleeve t slides.
The number of oscillations given to the armature by the inward motion of the
sleeve will depend on the number of undulations in the cam groove m and the
extent to which the sleeve is moved.
The oscillations given to the armature by the inward movement of the sleeve are
repeated by the return motion of the said sleeve which is effected by a spring w
interposed between the end of the armature spindle and a shoulder or projection in
the interior of the sleeve.
The hollow shaft or sleeve t may be connected to or caused to act on the
hammer of the bell in any convenient manner so as to move it out of the range of
the gongs when the sleeve is being operated and to return the hammer into position
to strike the gongs when the sleeve returns to its normal position.
In the drawing, I have shewn the hollow shaft or sleeve connected to the
lever G. (carrying the bell hammer L) by a link æ and loose collar
so as to move
the hammer with the shaft and also allow it to oscillate thereon with the
armature. To admit of the hammer sounding the bell when the shaft is in its
normal position the cam slot m is increased in width at the end where the pin
enters it to admit of its vibrating thereon when a current is received.
Instead of the cam groove being provided in the sleeve a pin or projection may
be provided therein to work in a groove formed in the armature spindle.
Instead of the cam or undulating groove hereinbefore described a screw thread
may be formed on the armature spindle and a pin or projection in the interior of
the hollow shaft or sleeve be caused to engage therewith so as to give to the
armature the necessary oscillations by the longitudinal to and fro motions of the
said hollow shaft or sleevc.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is
First In magneto electric telephonic apparatus extensions on the respective
noles of the mornate weed for
2432
the

page_text: which extensions the transmitter coils and the receiver coils are mounted so
that the extensions constitute the cores of the coils and are magnetised by the
said magnets substantially as hereinbefore described with reference to the accom-
panying drawings.
Second In a magneto-electric telephonic apparatus coils of the receiver and the
transmitter mounted on extensions on the respective poles of the magnet used for
giving the current for sounding the bell, the transmitter and receiver coils cach
being contained in a recess or shallow box in the case of the apparatus and having
a diaphragm clamped over it substantially as herein before described and illustrated
in Figures 1 and 2 of the accompanying drawings.
Third In a magneto-electric telephonic apparatus a bell hammer connected to
the armature or generating coil in such a manner that when the said armature or
coil is operated for sounding a distant bell the bell hammer of the sending
instrument will be moved substantially as herein before described so that the bell of
the sending instrument will not be sounded.
Fourth In a magneto-electric telephonic apparatus providing the generating
armature or coil with a handle to which the striker of the bell is also attached, the
handle being so connected to the armature as to be capable of being moved so as to
operate the armature for ringing a distant bell without causing its own bell to ring,
the handle and striker when released returning automatically under the action of a
spring or springs to their normal position for sounding the bell, substantially as
hereinbefore described.
Fifth The combination and arrangement of parts constituting the improved
magneto-electric-telephonic apparatus substantially as hereinbefore described and
illustrated by the accompanying drawings.
Dated the 17th day of June 1891.
J. H. JOHNSON & Co.