Improvements in Electro-telephonic Apparatus.
Year: 1892

page_text: Date of Application, 26th May, 1892
Complete Specification Left. 25th Mar., 1893-Accepted, 6th May, 1893
PROVISIONAL SPECIFICATION.
Improvements in Electro-telephonic Apparatus.
I CHARLES JAMES GRIST of 53 Gracechurch Street in the City of London
Electrical Engineer do hereby declare the nature of this invention to be as
follows:-
This invention has for its object to further increase the efficiency of the telephones
described in the Specification of Ernest Frank Furtado and for which Letters Patent
were granted to him numbered 5008 and dated March 31st 1890 by placing in the
bases or stands of such telephones a transmitter instead of using the telephone as
both transmitter and receiver.
Now according to this invention I make the stand of the telephone which contains
the call bell coil somewhat deeper than usual and above the bell coil I form a recess
in which I place a microphone and above the microphone I attach a transmitting
diaphragm the microphone being connected to the battery and line in the
usual way.
1000
ERNEST SALAMAN,
61 & 62, Chancery Lane, London, Agent for Applicant,
Patent Agent to the British and Foreign Patents and Trade Marks Society.
COMPLETE SPECIFICATION.
Improvements in Electro-telephonic Apparatus.
I CHARLES JAMES GRIST of 53 Gracechurch Street in the City of London
Electrical 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 has for its object to further increase the efficiency of the telephones
described in the Specification of Ernest Frank Furtado and for which Letters Patent
were granted to him numbered 5008 and dated March 31st 1890 by placing in the
bases or stands of such telephones a transmitter instead of using the telephone as
both transmitter and receiver.
Now according to this invention I make the stand of the telephone which contains
the call bell coil somewhat deeper than usual and above the bell coil I form a
recess in which I place a microphone and above the microphone I attach a
transmitting diaphragm, the microphone being connected to the battery and line
wire in the usual way.
And in order that my said invention may be fully understood I will proceed to
explain the same with reference to the accompanying drawing in which
Figure I represents a section of a telephone constructed according to this
invention.
Figure II is a partial section of the same at right angles to the section shewn in
Figure I.
The same letters denote the same parts in all the figures.
a is the gong of the call bell to which is attached the telephone coil b. c is the
telephone mouthpiece constructed of wood vulcanite or other suitable material.
d the diaphragm e the permanent magnet. f the handle which also serves as a lock
nut for the screw g by means of which the distance between the pole of the coil b
and the diaphragm d is adjusted.

page_text: h is the transmitting diaphragm to which is attached by means of the lugs i i one
or more carbon pencils k. I is the bell coil m the armature thereof to which the
clapper m² is attached, the armature m is attached to a spring so that when the
key n at the sending station is depressed the armature m is attracted towards
the coil and on the said key being released the spring raises the said armature
and the clapper attached thereto strikes the gong a. n is a Morse key making
contact with o and p for the purpose of sounding the call bell at distant station or
receiving a call from distant station respectively 9 is an induction coil for actuating
the microphone receiver r is the stand of the instruments is an automatic switch
operated by the spring t and the weight of the telephone u is a vertical rod
through which the weight of the telephone is transmitted to the spring t. v is a
contact piece w and x are contact springs 2 is contact piece attached to spring t.
The wiring of the instrument is as follows:-
B is the battery L the line wire C the call bell wire P wire connected to primary
coil passing round induction coil 9. S wire connected to secondary coil of the same
E wire to earth. When the receiver is in the position shewn at Figure I a circuit
is established from line L through automatic switch S and contact piece to the
key m and from thence through the contact p and wire C through the bell coil
and wire E to earth so that on a person at the distant station pressing his call
key m the gong at the receiving station is sounded. When the person at the
receiving station removes the receiver from the stand the spring t rises and forces
the contact piece z between the springs and wo thereby switching off the bell
circuit and establishing a circuit from line L through spring t contacts zx and
wire S to receiver coil 6 and thence through secondary coil of induction coil
to earth. At the same time a second circuit is established from line through
spring contacts z and w through wire P and primary coil of induction coil q to
the microphone and thence through line P¹ to earth.
When the key m is depressed a current is sent from battery through contact o
and wire C to line and round bell coil at distant station sounding the gong at that
.station.
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 :-
:-
1. In electro-telephonic apparatus the combination of a gong forming a case or
cover for the receiver mechanism with a stand containing a microphone transmitter
induction coil for operating the same and a means for sounding the said gong
substantially as described and shewn.
Dated this 25th day of March 1892
-
ERNEST SALAMAN,
Agent for Applicant.