Improvements in Telephonic Apparatus.
Year: 1892

page_text: Date of Application, 16th June, 1392-accepted. 8th Oct., 1892
COMPLETE SPECIFICATION.
Improvements in Telephonic Apparatus.
I CESAR VOGT, of Posen, in the Grand Duchy of Posen in the German Empire,
Electrician, 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 relates to improvements in telephonic apparatus and has for its
object to adjust the poles of a telephone relatively to the field of oscillations of the
membrane, this being effected in such a manner that one pole is enclosed in the
other which has a tubular form, while the two poles can be moved vertically to and
from the membrane by means of a suitable set screw.
In the accompanying drawings,
Fig. 1 shows a telephone in its normal position.
Fig. 2 shows a telephone where the south pole s. p. is moved nearer to, and the
north pole n. p. further from the membrane.
Fig. 4 is a sectional view showing the manner in which the poles are arranged in
the telephone.
The south pole s. p. which is a tube surrounding the north pole n. p. is fixed to
the upper branch of the magnet while the said north pole is secured to the lower
branch of the same.
The south pole s. p. consists of a short tubular piece, and the north pole n. p.
of an iron rod which is surrounded by that tubular piece as clearly shown in
Fig. 4.
The bobbin with the wire coils e. e. is placed inside the south pole s. p. In
consequence of this arrangement the north pole n. p. is placed in the centre of the
membrane m, while the south pole is removed from such centre and divides this
membrane m circularly and concentrically to the north pole n. p. Within the
lower branch b of the magnet M is arranged an adjusting screw i which is secured
by the small screws d. d. and with the aid of the small plates c. c. in such a manner
that it can be turned without being shifted from its position.
This adjusting screw i connects the two branches a and b of the magnet M so that it
is possible by turning the adjusting screw i to the left to remove whenever required
the north pole n. p. from the membrane (Fig. 2) and to bring at the same time the
south pole s. p. nearer the latter. By this arrangement the position of the two
concentric poles relatively to the membrane m can be accurately adjusted.
As compared with other systems this telephonic construction has the following
chief advantages.
1. Highest efficiency owing to the position of the poles which are concentric to
the membrane, while they form the greatest number of lines of magnetic force,
which lines transverse the membrane vertically.
2. Fullest result of the action of the electric current obtained by the use of a
bobbin, as this current operates in a reverse direction on the two inverted poles.
3. The round form of the poles allows, as compared with longitudinal poles, the
most intimate and advantageous winding.
4. Smallest possible resistance only one bobbin being used for two working
poles.
5. Most thorough adjustment of the two poles relatively to the membrane, as the
former can be set by means of the adjusting screw i to fit the wave-like vibrations of
the membrane.
6. Thorough protection of and inaccessibility to the thin wire convolutions e. e. of
the bobbin as the latter is surrounded at the top and at the bottom by the bobbin
discs f. f. and at the side by the tubular pole s. p.

page_text: 7. Smallest possible weight and handy form combined with increased efficiency,
as the two poles are only provided with one bobbin.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
A telephone with two poles having a bobbin in which the said two poles are
arranged concentrically to the membrane and can be adjusted relatively to the
vibrations of the membrane, substantially as herein described and shown and for the
purpose set forth.
1
CT
1000
HUGHES, SON & Co.,
38, Chancery Lane, London, Agents for the Applicant.