Improvements in and relating to Telephones.
Year: 1897

page_text: Date of Application, 6th Sept., 1897-Accepted. 23rd Oct., 1897.
[Communicated from abroad by CARL KRAFT, Electrician, of 17 St. Apolodor,
CARL HUBER, Engineer, of 7 St. Baterulor, and I. JOSEPH EXNER, Architect,
of 23 Calea Dorobantilor, all three of Bucharest, in the Kingdom of
Roumania.]
Improvements in and relating to Telephones.
I, CHARLES JUNGE, of Lincoln Chambers, 75 Chancery Lane, London, W.C.,
Consulting 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:—
This invention relates to the construction of telephones designed for continuous
and alternating currents, the polarized membrane or diaphragm of which is per-
fectly insensitive to induction, which has a disturbing effect when several
subscribers are speaking. This is accomplished by rendering the action of all
currents except that of the direct current upon the diaphragm impossible, because
the diaphragm is influenced solely by the secondary circuit of a transformer
included in the primary circuit, such transformer serving in conjunction with a
commutator, in the case of a continuous current and also in that of alternating
currents, for operating a polarized or alternating-current bell, so that for alternating-
current telephones the inductors, which greatly increase the cost of the installation,
will be dispensed with.
In the accompanying drawings
Figure 1 shows a plan of the improved telephone, and
Figure 2 a plan as seen from below
Figure 3 represents a section on the line C-D of Figure 1, and
Figure 4 a section on the line A-B of Figure 2.
Figure 5 is a plan of a modification of the diaphragm.
Figures 6, 7, 8 and 9 illustrate two different forms or modifications of a manual
telephone.
Figures 10, 11 and 12 represent other forms or modifications of the diaphragm.
Figure 13 shows an elevation of the transformer, and
Figure 14 a plan of the same.
Figure 15 is a front elevation of a roller commutator,
Figure 16 a side elevation, and
Figure 17 a plan of the same.
Figures 18 and 19 are transverse sections on the line G-H and E-F of the
roller commutator, and
Figure 20 is a diagram illustrating the arrangement of the circuits."
As clearly shown in Figures 1 to 5, the membrane or diaphragma of the
telephone consists of a plate of non-magnetizable metal, into which is soldered
an iron tongue a extending from the centre to the periphery and protruding on

page_text: the outside a certain distance beyond the periphery of said plate. The diaphragm
possesses a thickened edge which has for its object to put the diaphragm in tension
by slightly flattening such edge. It is held upon a bed plate 6, upon which are
fixed two horse-shoe magnets chaving like poles facing each other. To one
pole of these two magnets cd is secured a bridge piece d which extends to the
centre of the diaphragm and carries at its two ends the cores e el adapted to be
adjusted at right angles relatively to the diaphragm and appertaining to the
bobbins ff included in the secondary circuit of the transformer. After the
adjustment the cores e e¹ are fixed with the aid of the set screws g g'. The other
two adjoining poles of the permanent magnets c c are embraced by the free
end of the iron tongue a¹ of the diaphragm a, this free end being firmly united.
by screws a to the pole ends in order to obtain a sure magnetic connection. By
this iron tongue the magnetic lines of force, to which the diaphragm is sub-
jected, are concentrated and the magnetic self-induction of the diaphragm is
reduced to such an extent that it cannot have a disturbing effect.
In the case of manual telephones, in which the diaphragm is of a considerably
smaller diameter, I may also make such diaphragm of non-magnetizable metal and
use an iron tongue (Figures 6, and 10), or I may make it entirely of soft iron
(Figures 7 and 9). In the latter case however a piece must be cut away in
order to obtain a more advantageous action of the magnetic lines of force and
to diminish the self-induction, as shown in Figure 11. When a continuous
current is employed the diaphragm, as illustrated in Figure 12, is made as usual
of iron with a tension edge.
Figures 6, 7, 8 and 9 show two constructional forms or modifications of manual
alternating-current telephones. Figures 6 and 8 illustrate tongued diaphragms,
and Figures 7 and 9 iron diaphragms, Figures 6 and 7 being plans and Figures 8
and 9 the corresponding vertical sections. In this case the permanent magnets cc'
are ring magnets, with which the arms d carrying the cores e e¹ are made in
one piece.
The transformer, in the secondary circuit of which the telephone bobbins f f
are included, is represented in Figures 13 and 14 and consists of a horse-shoe
magnet of soft iron wires the free ends of which are connected by a yoke or
pole piece h¹, whilst each of the arms carries a bobbin 2 with primary and
secondary windings.
The commutator serving in combination with the transformer for calling
(Figures 15, 16, 17, 18 and 19) consists of a roller i of insulating material, which
carries on its periphery small contact plates k₁, each of which closes a circuit
by means of a pair of contact springs m m¹ m³, those designated by k being
arranged three times at equal distances apart upon the periphery of the roller,
whilst the others are likewise arranged at equal distances apart half way
between the small contact plates & upon the periphery of said roller. A cam
disc is fixed together with the rubber roller upon the shaft which may be set
in rotation by a crank 2. Upon the periphery of the cam disc / acts a roller /¹
adapted to rotate at the end of a spring, so that the rubber roller is each time
fixed in the position corresponding to the small contact plates k, whilst a stoppage
of the roller cannot take place at the point where the small plates ¹³ close their
circuit, the closing of the circuit being only momentary owing to the small
plates, so that it will be possible to operate the alarm at the other station
by the opening and closing of the circuit by means of the commutator.
The diagram illustrating the arrangement of the circuit for a station is
represented in Figure 20.
Each station has a microphone p, a telephone n, an automatic switch o, operated
by the removal of the telephone n, a transformer in the secondary coil of which
the telephone n is included, and in the primary coil of which the microphone 2
and the battery s are included, a polarized bell q, a lightning conductor u, and
the commutator i.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is:-
First. A telephone for continuous and alternating currents, characterized by
the arrangement of a polarized membrane or diaphragm a between two electro-
magnets ff arranged in the centre of the same at right angles to it, the cores e e¹
of such electromagnets having magnetic connection with the poles of two per-
manent horse-shoe magnets or ring magnets c c facing each other with like poles,
whilst the exciting coils are included in the secondary circuit of a transformer h,
the latter serving in combination with the commutator i also for the purpose of
calling, substantially as set forth.
Second. A constructional form of the telephone as in the first claim, character-
ized by the feature that the polarized membrane or diaphragm consists of non-
magnetizable metal and possesses an iron tongue a extending from the centre to
the periphery and beyond the latter, the protruding end having a magnetic
connection with the abutting poles of the permanent magnets cc', substantially
as set forth.
Third. A constructional form of the telephone as in the first claim, characterized
by the arrangement of a polarized membrane or diaphragm a of iron with a piece
removed from one side, substantially as set forth.
Fourth. In a telephone as in the first claim a commutator included in the
primary circuit of the transformer, characterized by the feature that contact
pieces are arranged three times upon the periphery of a roller of insulating
material in such a manner that the latter two contact pieces are situated in the
same peripheral line of the roller and always half way between the former contact
pieces, and that the roller is held by a ratchet or stop in the position wherein k
connects its contact springs m, whilst the closing position of the other
two contacts is not a position of rest, for the purpose of enabling this
commutator to be used, not only for closing the circuit while speaking, but
also for calling, substantially as set forth.
Fifth. In telephones membranes or diaphragms characterized by a thickened
edge which, being flattened with a hammer to a slight extent, enables the mem-
brane or diaphragm to be put in uniform tension, and does not permit any bubbles
to be produced, substantially as set forth.
Dated thin Cth dox of Santambor 1807