IMPROVEMENTS IN TELEPHONES
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by the said Allan Westley Rose at the
Office of the Commissioners of Patents on the 12th December 1881.
ALLAN WESTLEY ROSE of Kirby Street Hatton Garden in the County of
Middlesex. "IMPROVEMENTS IN TELEPHONES."
My Invention relating to improvements in telephones consists in the employment
of a compound diaphragm, the central portion of which is made of a thin material
and the outer portion of a comparatively thick material by which I obtain a more
effective action of the diaphragm, the thinner portion first yielding to the full
extent allowed by its elasticity and then evoking the action of the thicker portion
which then comes into play and cooperates with the thinner portion of the
compound diaphragm.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Allan Westley Rose in the Great Seal Patent Office on the
12th June 1882.
ALLAN WESTLEY ROSE of Kirby Street Hatton Garden in the County of
Middlesex. IMPROVEMENTS IN TELEPHONES."
"
My Invention relating to improvements in telephones consists in the employment
in a compound diaphragm the central portion of which is made of a thin material
and the outer portion of a comparatively thick material by which I obtain a more
effective action of the diaphragm than has hitherto been obtained the thinner
portion first yielding to the full extent allowed by its elasticity and then evoking
the action of the thicker portion which then comes into play and co-operates with
the thinner portion of the diaphragm.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the annexed Sheet of Drawings the same letters of reference indicating
corresponding-parts-in-both-the-Figures.
Figure 1 of the said Drawings represents a section of a portion of a telephone
with the improved diaphragm applied thereto Figure 2 is a plan of the diaphragm
detached.
A is the improved diaphragm which consists of a thin central portion a and a
relatively thick outer portion a¹. The central and outer portions may either be
made separately and soldered or otherwise attached together as indicated in the
Drawings or the diaphragm may be stamped or otherwise formed so as to obtain
the two different thicknesses from one disc.
The diaphragm is fitted into any suitable case B in any of the usual and well
known manners.
In the operation of instruments fitted with the improved diaphragm the central
portion a first yields to the full extent 'allowed by its elasticity and then evokes
the action of the thicker portion a¹ which next comes into play and co-operates
with the thinner portion a of the diaphragm.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the herein-before in part
recited Letters Patent is,
The employment in telephones of diaphragms consisting of a central thin portion
and surrounding relatively thick portion substantially as and for the purpose
herein before described.
In witness whereof I the said Allan Westley Rose have to this my
Specification set my hand and seal, this Ninth day of June One thousand
eight hundred and eighty two