Telephones, and the like.
Year: 1888

page_text: Telephones, and the like.
I JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been communi-
cated to me from abroad by The Volta Graphophone Company of Alexandria Virginia
a corporation organized under the laws of the State of Virginia and having an
Office in Washington District of Columbia 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 mode of mounting the diaphragm of a graphophone
telephone or other apparatus employing a vibratory diaphragm adapted either to
respond to or set up sonorous atmospheric vibrations the diaphragm being of metal
mica or other suitable material.
In the use of apparatus of this character it is found that if the diaphragm be not
supported in a perfectly even plane that is to say if it be in the least bent or buckled
its amplitude of vibration is interfered with and the operation of the instrument is to
a corresponding degree impaired. To avoid such difficulty it has been found desirable
that the devices between which the diaphragm is clamped at its edges should have a
very narrow bearing surface or edge in contact with the diaphragm and should be
slightly elastic so as to ensure a continuous contact with the diaphragm notwithstanding
any slight difference in thickness in different parts of the diaphragm.
To this end the diaphragm according to the present invention is clamped between
two thin metal washers grooved or struck up so as to present a bearing edge for
contact with the diaphragm the shape of the washers giving them the slight elasticity
requisite for the purposes of the invention. The form of the washers in cross section
may be angular or that of a segment of a circle or of other convenient shape.
While it is preferred to use such a washer on each side of the diaphragm a single
washer may be used with good effect.
The accompanying drawings illustrate several ways of carrying out the invention
Fig I being a plan view Fig. II a section and Figs. III to VII sectional details drawn
to a larger scale.

page_text: The diaphragm a is shewn as supported by a ring A which may be part of the
frame of a telephone transmitter or receiver or of a graphophone recorder or repro-
ducer provided with an internal shoulder b. One of the metal washers c rests upon
this shoulder the diaphragm a is placed upon the washer and a second washer c is
laid upon it and the cap d is then screwed down tightly securely clamping the parts
in place.
In Figs. II and III the washers care of concavo-convex form and they are arranged
with their convex sides in contact with the diaphragm. Washers of this form may
as shewn in Fig. IV be arranged with their concave sides towards the diaphragm.
The washers may as shewn in Figs. V and VI be V-shaped or angular in cross section
and they may be placed with reference to the diaphragm in the position shown in either
of these figures.
As shewn in Fig. VII the diaphragm a may have an elastic washer c on one side
only and such construction would be within this invention. As shewn in this figure
the shoulder b on the ring A is provided with a bead or rib e
and diameter with the washer c. The bead could of course be on the cap d and the
washer on the opposite side of the diaphragm.
corresponding in shape
In all cases it is desirable that the bearing edges of the two washers should be
exactly opposite to each other and to that end they should be of the same diameter and
preferably of such diameter as to fit accurately inside the supporting ring
they are properly centered.
whereby
The washers c are conveniently made from sheet metal punched out and struck up
at one operation.
It will of course be understood that if the diaphragm be used in a graphophone it is
connected with the recording or reproducing style or if in a telephone it is combined
with the operating parts thereof in the manner well known to those skilled in
such arts.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. The combination with a vibrating diaphragm of a grooved or struck up metal
washer in contact with said diaphragm at its edge and supporting and clamping devices
substantially as hereinbefore described.
2. The combination with a vibratory diaphragm of two grooved or struck up metal
washers one on each side of said diaphragm said washers being turned in opposite
directions so that corresponding sides thereof are in contact with said diaphragm
substantially as hereinbefore described.
3. The combination with a vibratory diaphragm of two metal washers of concavo-
convex form one on each side of said diaphragm and clamping devices substantially as
herein before described.
Dated this 13th day of November 1888.