Improvements in Telephones.
Year: 1890

page_text: Date of Application, 29th Oct., 1890
Complete Specification Left, 29th July, 1891-Accepted, 29th Aug., 1891
Improvements in Telephones.
We EUGEN HARTMANN and WUNIBALD BRAUN both of Bockenheim Frankfort
on Main in the Empire of Germany Electrical Engineers do hereby declare the
nature of this invention to be as follows:-
Telephones constructed according to this invention are capable of emitting loud
sounds relatively to their size and are not liable to vary in their action.
In these improved telephones an annular magnet is arranged at the back of the
diaphragm and parallel thereto in a flat circular box or case of metal or suitable
materials. This magnet is constructed with a thin plate or disc of sheet steel
highly tempered or hardened and provided with a hole in the centre.
The poles
are formed by plates attached at opposite sides of the annular magnet and provided
at their inner ends with iron pins perpendicular to the plates upon which pins the
conductor is wound in the form of coils of fine wire or the plates may be simply
provided with three pins for example having a bobbin of small dimensions placed
on each pin to carry the conductor or coils of wire. This arrangement has the
advantage of utilizing the wire to the best advantage.
In order to obtain correct poles it is advantageous to construct the annular
magnet with two half rings connected to the pole plates by screws.
In order to enable the ends of the pole pins to be adjusted in a plane parallel to the
diaphragm, the magnet is supported on springs passed over pins er screws fixed in
projections in the side of the case and provided with nuts which enable the maguet
to be accurately adjusted relatively to the diaphragm.
The diaphragm is provided with a correcting device or means for its adjustment
in order to enable the telephone to be regulated or adjusted to different degrees of
sensitiveness.
With this object the tubular telephone case is provided at its front end with an
adjustable ring concealed in the case under the diaphragm. This ring supports the
diaphragm which is connected thereto by screws engaging with the mouth or
ear piece. In a shoulder on the side of the case there is a groove or channel in
which a pin is inserted. When the ring is unscrewed a pin inserted in the ring
after it has been screwed on to the case comes in contact with the pin in the groove
and limits the movement of the ring. The ring is further provided at another point
with a screw by which the ring and the case can be firmly screwed together. This
screw is formed with an ordinary nick but the screws which engage with the mouth
piece are preferably arranged to be unscrewed by a special key thus rendering the
interior of the telephone more difficult of access.
The shoulder on the case may be provided with a depression in place of the
groove and stops hereinbefore referred to for limiting the movement of the adjusting
ring.
Dated this 20th day of October 1890.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, Agents.

page_text: Improvements in Telephones.
We, EUGEN HARTMANN and WUNIBALD BRAUN both of Bockenheim, Frank-
fort-on-the-Main in the Empire of Germany, Electrical Engineers 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 :—
Telephones constructed according to this invention combine the advantages of
being capable of emitting loud sounds relatively to their size and of being very
permanent or uniform their action. These results are obtained by means of an
arrangement hereinafter described according to which the conductor is wound upon
pins attached to the pole plate at right angles to the diaphragm or vibrating
membrane. Means are also provided for adjusting the position of the diaphragm
in order to regulate the action of the telephone as hereinafter explained.
And in order that our said invention may be fully understood we shall now pro-
ceed more particularly to describe the same and for that purpose shall refer to the
several figures on the annexed sheet of drawings the same letters of reference
indicating corresponding parts in all the figures.
Figure 1 of the accompanying drawings represents a telephone constructed
according to this invention the diaphragm being removed in order to expose the
interior.
Figure 1 represents the telephone in section and Figure 1° illustrates the magnet
removed from the case.
Figure 1 illustrates a modified arrangement hereinafter described and
Figures 2, 24, 28 and 3 relate to the means employed for adjusting the magnet
and diaphragm.
The telephone is provided with an annular magnet A arranged at the back of the
diaphragm and parallel thereto in a flat circular box or case B of metal or other
suitable materials. This magnet is composed of a plate or disc preferably of steel
highly tempered or hardened being from about 2 to 4 millimetres in thickness
according to the size of the apparatus and presenting a hole or opening in the
centre. The poles of the magnet are formed by iron plates C attached to the
opposite sides of the annular magnet as represented in Figure 10. The ends of
each of these plates are provided as shown in Figures 14 and 10 with a series
of iron pins D upon which the conductor is wound in the form of coils of fine
wire. According to another arrangement illustrated in Figure 1º the plates C
are simply provided with three pins D a bobbin of small dimensions being
placed on each pin to carry the conductor or coils of wire. This arrangement
has the advantage of utilising a given quantity of wire to the best advantage.
In order to obtain correct poles it is advantageous to construct the annular
magnet with two half rings connected together by means of the pole plates C to
which they are attached by screws for example as represented in the drawing.
In order to enable the ends of the pole pins D to be adjusted in a plane parallel
to the diaphragm M Figure 1B the magnet is supported on springs & passed over
pins t fixed in projections æ in the side of the case. By rotating nuts m working
on these pins, the magnet is enabled to be accurately adjusted relatively to the
diaphragm.
The diaphragm is provided with a correcting device or means for regulating its
position in order to enable the telephone to be adjusted to different degrees of
sensitiveness.
Figures 2 and 24, 2 and 3 illustrate two arrangements for regulating the
action by adjusting the position of the diaphragm within certain limits.
With this object the tubular telephone case B Figures 2 and 24 is provided at
its front end with an adjustable ring R screwed on the end of the case and

page_text: supporting the diaphragm (not shewn in Figures 2 and 24) which is retained in
position between this ring and a mouth or ear piece K as indicated in Figure 3, the
part K being connected to the ring R by means of screws one of which is represented
in dotted lines at Figure 3. In a shoulder formed on the side of the case there is
a groove or channel provided with a stop pin p Figure 2ª.
When the ring R is rotated on the case for the purpose of regulating the action
a pin p' which is inserted in the ring after it has been screwed on to the case comes
in contact with the pin p in the groove and limits the rotary movement of the ring.
The ring is further provided at another point with a screw O Figure 3 by which
the ring is enabled to be fixed in position on the case. This retaining screw is
formed with an ordinary nick but the screws are preferably so arranged that they
cannot be unscrewed except by a special key thus rendering the interior of the
telephone more difficult of access. According to the arrangement illustrated in
Figure 2B the shoulder on the case is provided with a recess of limited extent in
place of the groove and stop pin and a pin p' attached to the ring R limits the
movements of the ring by coming in contact with the ends of the recess and
enables the distance of the magnet from the diaphragm to be regulated within such
limits as are required for the proper action of the telephone.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what
we claim is :-
1. In a telephone the combination of an annular magnet arranged parallel to the
diaphragm with pole plates carrying pins projecting at right angles to the plane of
the diaphragm and upon which the conductor is coiled substantially as hereinbefore
described with reference to Figures 14 1B 1C and 1" of the accompanying drawings.
2. In a telephone a ring supporting the diaphragm and adjustably connected to
the case for the purpose of enabling the action of the telephone to be regulated or
controlled substantially as hereinbefore described with reference to the Figures 2,
2A 2B and 3 of the accompanying drawings.
3. The arrangements and combinations of parts constituting the improvements in
telephones substantially as hereinbefore described and illustrated in the accompanying
drawings.
Dated this 29th day of July 1891
J. H. JOHNSON & Co.,
Agents.