Year: 1899

page_text: Date of Application, 10th July, 1899-Accepted, 30th Dec., 1899.
s to be performed to be particularly described and ascertamed in and by the
following statement:—
This invention relates to an improved telephone installation comprising
microtelephone apparatus, annunciators for indicating the source of the calls
and connecting devices serving to connect the central station to the line indi-
cated by the annunciator, the respective mechanisms being of the improved
constructions hereinafter described and very small in size and the whole
installation being devised to occupy a minimum of space.
On the accompanying drawings:-
Figure, 1, represents the improved indicator in longitudinal section;
Fig. 1, is a transverse section thereof;
Fig. 2, is a longitudinal section of the improved connecting device;
Fig. 2, is another section thereof on a different plane, showing the contact
plates;
Fig. 3, is an elevation of the microtelephone showing both the transmitter
and the receiver; and
Fig. 3bis, is a section thereof on a vertical plane passing through its axis.
In the microtelephone apparatus, vido Figs. 3 and 3, the transmitter and
the receiver are combined and arranged back to back so as to form a single
instrument having the appearance of a cylindrical box, c, the ends of the
instrument being formed by the membrane, a, of the transmitter and the
membrane, b, of the receiver, which are located against the body of the box
(which is fitted with a suspension ring, d,) by mouth-picces or fastening
rings, a¹, b
,, (Fig. 3) represent the poles of a permanent magnet of suitable form
cores projecting from which are fitted with coils, e, placed in suitable relation
to the soft iron receiver membrane, b, this part of the instrument constituting
the receiver:
The microphone transmitter is formed with a celluloid membrane, a to the
centre of which the microphone, s, is screwed. This latter consists of an ebonite
or bone ring, r, which recoives on each of its faces a thin carbon disk. One
of such disks is secured by a copper cap screwed into the rim of the ring, and
the other disk is secured by a copper spring ring, e' which also serves as part of
the circuit.
The space between the two disks is filled with very finely granulated carbon.
A thin metal plate screwed at the same time as the microphone to the centre
of the celluloid membrane, gives the electrical communication of the microphone
by means of the screw, n.
The electrical connections are the same as those of all telephone instal-
lations that work with primary circuit. The current under tension passes
through the two coils of the receiver and the microphone. The use of an

page_text: induction coil is of course applicable to the hereindescribed installation in such
cases where it is desired as for instance to connect the installation with the
public system.
13
The annunciator, vide Figs. 1, and 1bis, is formed with a right angled
frame, f, g, of soft iron the part, f, carrying a core and coil and an insulated
contact point, h¹, in connection with the copper pole of the battery; and the
part, g', carrying an armature, h, fitted with a plate, &, adapted, at the moment
of attraction of the armature, to make contact with the point, h¹; and also
with a bent copper piece, 1, adapted to maintain in its normal position the
shutter, r, which has a label carrier, s¹. A straight copper spring, o, ensures
the return of the armature and also renders more certain the contact of the
armature with the frame part, gl. A copper button, v, fitting tightly on the
arbor of the shutter, enables the latter to be reset after its fall.
The improved annunciator is of advantage in that;-The indicator labels can
be made of large size without sensibly increasing the bulk of the annunciator
as a whole; they are not visible when the apparatus is not at work so that
no one can tell what persons are called up as is the case when such indications
are inscribed on the front of the indicator board and stay there; the re-setting
of the indicator is independent for each annunciator in lieu of being effected
by a resetter common to all the annunciators;-and the construction is so
simple as to facilitate inspection and repair.
The said connecting device is formed with a body of wood, ebonite or other
suitable insulating material supporting two contact plates, a", 6", so arranged
that a cross-piece, i, at the end of the sliding rod, d, may be set in contact
with one or the other of such plates accordingly as the rod is drawn or pushed
in the direction of the arrows, s", like an organ stop. A button, ", at the
other end of the rod carries at its face the indication of the piece corresponding
to the line served' by the device.
Fig. 2b, clearly shows how the blades, a", 61, are shaped so as only to
allow of the cross-piece, ¹, touching one or the other thereof at a time.
The advantages of this improved device are that: The contacts being effected
by a rubbing motion are very good;-the indications of the position of the
apparatus in the two cases of rest and service are very clear;-the size or
bulk of the apparatus is very small which facilitates their examination and
repair.
The electrical connections of the three above apparatus are shown on the
drawing. At rest, the circuit is established so that the current from the calling
station arriving by the terminal, w, passes through the connecting device, 1,
(Figs. 2, 2b,) and by the metallic parts, , a", passes to the coil of the annun-
ciator which it traverses in returning to the return terminal, r, of the calling
current. The armature, h, of the annunciator, when thus attracted, at the
same time that it releases the indicator plate or shutter, r, closes the local
battery bell circuit, 2, 3, 3, 3, 3, 3, 3, g.
At the call, the attendant at the central station withdraws the rod of the
connector so as to place the station in connection with the calling station and
at the same time to put the annunciator out of circuit.
This is effected by the oross-piece, ¹, of the connector rod breaking contact
with the plate a", which connected it to the annunciator, and making contact
with the plate, 6", which connects it to the key or button of the calling
station, L. It suffices therefore to press on the call button in order to ring up
directly the calling station without passing through the annunciator. If the
station calls again the bell will be worked by its current and no longer by that
of the local battery, g, 2, since the current will pass by, w, 1, 6", L, T, S, 3, 3,
and ¹.
The central station comprises, as well understood, as many annunciators and
connectors as there are stations with which it is desired to communicate
talanhonicall

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. A central domestic telephone station, characterized by a microtelephone
apparatus in which the transmitter and the receiver are together arranged to
form an apparatus of cylindrical form, of which the ends are formed by the
respective membranes of the transmitter and the receiver presenting an apparatus
of very small bulk and easily portable; by an annunciator having a label
carrying shutter which becomes disengaged from a square secured to the
armature, and by a connector comprising beut contact plates and a cross
contact piece actuated by the push and pull on a rod, as set forth.
2. In a telephone post or station as in Claim 1, the arrangement of a micro-
telephone apparatus comprising a cylindrical box, c, having secured at one of
its ends by a ring, a', a soft iron receiver membrane, b, and formed with an
internal shoulder to which is screwed a permanent magnet, cores projecting
from the poles, i, of which carry coils, e, and terminate close to the membrane, b,
these devices constituting the receiver; and having secured to its other end a
celluloid membrane, a, to the centre of which is screwed a microphone con-
sisting of a ring, r, two carbon disks, a cap, s, a spring ring, e', and a metal
plate electrically connecting the transmitter to the receiver by the screw,n,
substantially as herein before described with reference to the accompanying
drawings.
3. In a telephone post or station as in Claim, 1, the arrangement of an indi-
cator comprising a square of soft iron, f, g, a coil, an armature, h, oscillating
about an axis, a plate, k, adapted to make contact with an insulated plate, h¹,
a copper bent piece, 7, serving to hold in its set position the shutter, r, carrying
the label carrier, sl, a straight spring, o, for returning the armature, and a
copper button,, fitting tightly on the arbor of the shutter and serving for
resetting the latter after its fall, substantially as hereinbefore described with
reference to the accompanying drawings.
4. In a telephone post or station as in Claim, 1, the arrangement of a con-
nector, comprising a body or base of wood or ebonite, two contact plates, well, ii,
a cross-piece, i, at the end of a sliding rod, d, and serving to make contact
with one or other of the plates a, b, a button, A, at the other end of the
rod, and carrying on its front face the indication of the piece corresponding to
the line served by the connector, substantially as hereinbefore described with
reference to the accompanying drawings.
Dalad th 10th day of T
DAY, DAVIES, & HUNT,
Chartered Patent Agents, 321, High Holborn, London, W.C.,
Agents for the Applicant.