IMPROVEMENTS IN TELEPHONIC APPARATUS
Year: 1883

page_text: LETTERS PATENT to George Henry Bassano Albert Edward Slater and
Frederick Thomas Hollins all of Derby in the County of Derby for an
Invention of IMPROVEMENTS IN TELEPHONIC APPARATUS
PROVISIONAL SPECIFICATION left by the said George Henry Bassano
Albert Edward Slater and Frederick Thomas Hollins at the Office of the
Commissioners of Patents on the 17th August 1883.
GEORGE HENRY BASSANO, ALBERT EDWARD SLATER and FREDERICK THOMAS
HOLLINS, all of Derby, in the county of Derby
"IMPROVEMENTS IN TELEPHONIC
APPARATUS."
This invention has for its object the greater simplification of apparatus for which
we applied for Letters Patent March 10th 1883 No 1290.
In the form of transmitter therein shewn we use carbon pencils of serrated or
fluted form fixed to the free end of a tongue sounding board and arranged in
multiple arc circuits.
"
Now we propose to obtain greater amplitude of vibration and dispense with the
tongue sounding board and fix our carbon pencils (or metallic contacts) across the
end of a trumpet mouthed case or speaking tube or trumpet and allow the sound
waves to directly strike the contacts.
The pencils or other form of contacts used may be fitted to the edges of and
within the tube or trumpet or in other convenient manner in connection with such
tube or trumpet.
We may if desired apply springs to adjust the contacts and prevent sudden
"breaks" in the circuit.
The contacts may be connected up as in our before recited Patent or they may
be connected in the ordinary manner for "quantity" or "intensity."
We find microphonic contacts so arranged have given us better results than
when used in connection with a diaphragm or tympan or tongue sounding board..
•

page_text: "disc
We may mount-our pencils or contacts directly on the "piston or plug'
or plate" referred to in the said specification and thus combine in one instrument
a transmitter receiver and relay.
This arrangement will be useful we believe in long distance telephoning as the
relay could transmit speech from station to station.
Wo find we can simplify the plate or tongue form of receiver mentioned in the
said specification by instead of fitting it to vibrate on a hinge or spring, by
making it of a resilient material (like pine for instance) and clamped at its lower
end or screwed so as to vibrate freely, the armature being attached to the said
plate.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Henry Bassano Albert Edward Slater and Frederick
Thomas Hollins in the Patent Office on the 14th February 1884.
GEORGE HENRY BASSANO, ALBERT EDWARD SLATER and FREDERICK THOMAS
HOLLINS all of Derby in the county of Derby. IMPROVEMENTS IN TELEPHONIO
APPARATUS
•
This invention has for its object the greater simplification of apparatus for which
we applied for Letters Patent March 10th 1883 N° 1290.
In the form of transmitter therein shewn we use carbon pencils of serrated or
fluted form fixed to the free end of a tongue sounding board and arranged in
multiple arc circuits.
Now we propose to obtain greater amplitude of vibration and dispense with tho
tongue sounding board and fix our carbon pencils (or metallic contacts) across the
end of a trumpet mouthed case or speaking tube or trumpet and allow the sound
waves to directly strike the contacts.
The pencils or other form of coutacts used may be fitted to the edges of and
within the tube or trumpet or in other convenient manner in connection with each
tube or trumpet.
We may if desired apply springs to adjust the contacts and prevent sudden
"breaks" in the circuit."
The contacts may be connected up as insour before recited Patent or they may
be connected in the ordinary manner for "quantity" or "intensity."
We find microphonic contacts so arranged have given us better results than
when used in connection with a diaphragm or tympan or tonguo sounding board.
We may mount our pencils or contacts directly on the "piston or plug" "disc
or plate" referred to in the said specification and thus combine in one instrument
a transmitter receiver and relay.

page_text: This arrangement will be useful we believe in long distance telephoning as the
relay could transmit speech from station to station.
We find we can simplify the plate or tongue form of receiver mentioned in the
said specification by instead of fitting it to vibrate on a hinge or spring by making
it of a resilient material (like pine for instance) and clamped at its lower end or
screwed so as to vibrate freely, the armature being attached to the said plate.
And we will now proceed to describe the accompanying drawings so that our
invention may be more clearly understood.
Figs. 1. 2. 3. 4. 4a. 5. refer to our improved microphone "tube" or "trumpet."
Fig. 6. shews our tongue" receiver.
Fig. 7. shews a similar receiver utilized as a transmitter, receiver and relay
combined..
Fig. 1. is a vertical cross section of one form of transmitter of a "speaking
trumpet" shape and which may be made of wood ebonite or any other suitable
material. M. is the mouthpiece, P the pencil contacts (preferably of carbon) B B¹
the blocks in which the pencils rest, t t the terminals by means of which tho
wires are attached to the blocks B B¹ the screws A A' holding the said blocks in
position, or other device may be used for this purpose. Although only one pencil is
shewn we may advantageously use two or more and these are of course in practice
inserted in the primary circuit of an induction coil as will be understood. G is the
collar fastened round the neck of the trumpet and by means of which it is shewn
fixed to a small stand or pillar so that it may be adjusted to any angle desired by
the speaker or it may be placed permanently in position.
Fig. 2. is a vertical cross section and Fig. 3. a plan of the end of another form or
modification of our transmitter being merely a trumpet mouthed case or elongated
mouth piece across the end of which the pencil contacts are fixed. A carbon button
or buttons such as is used with the "Blake Transmitter" may very conveniently
be fitted to this form of instrument if desired in preference to pencils.
In the drawing Fig. 2. it will be seen that instead of fixing the pencils at the
broad end as in Fig. 1. they are shewn fixed at the narrow end of what is practically
a similar shaped instrument and this may in some cases be found more effective
in collecting and concentrating the sound waves on the pencils or movable contacts
at the end
M is the end into which the operator directs his or her voice. B B' the blocks
of carbon or other material used and P P¹ the pencils (also preferably) carbon which
are connected in the primary circuit of an induction coil in the usual manner.
Fig. 4. however shews a vertical cross section of the same form of transmitter
fitted for multiple microphonic circuits as described in our patent No. 1290 of
March 10th 1883.
Although only one pencil is shewn in the drawing as in each primary circuit
(owing to its being a sectional view) the instrument is in fact fitted with two (or
may be with more) pencils in each circuit (as the single circuit is shewn in plan at
Fig. 3.) the upper and lower blocks of the two microphones being of course
insulated from each other at a a¹ Fig. 4. and although the upper and lower micro-
phones are shewn with their pencils or moveable contacts parallel to each other we
prefer to fix them in the form of a cross at right angles or diagonally the more
effectually to catch the sound waves when in operation. The drawing Fig. 4. will
be easily understood. B B¹ are two batteries of (as shewn)'three cells each. and PP¹.
the two microphones in the primary circuit P of the induction coil I-S being the
secondary wire ordinarily in circuit with line and earth through the receiving
telephone as will be understood. In actual practice there is also a switching
arrangement the principle of which is explained in our before-mentioned Patent for
disconnecting the separate batteries from the microphones and coupling them up
into one complete battery for the call bell or other suitable arrangement may
be used.
Fig. 4 A. shews a shorter form of a similar shaped instrument and with thick
solid sides being merely. a piece of solid wood with the inside turned out. It is a

page_text: Jongitudinal cross section so as to shew the pencil, M is the mouthpiece, P is the
carbon pencil and B B' are the carbon blocks in which the pencils rest. Only one
pencil is shewn but in practice we prefer to use two in multiple circuit-that is one
in each of two microphonic circuits and as one only is used, we prefer to use very
thick heavy pencils, firstly so that they will the more effectually catch the sound
waves, and secondly so as to prevent any break through the pencils jumping and
to render impossible any buzzing through the pulsatory vibration of the pencils
when the current is stronger. We sometimes prefer to use such pencils, one in each
of two microphonic circuits in connection with any or all the forms of transmitters
shown in this specification.
Fig. 5. is a vertical cross section of the "speaking tube" form of transmitter
the pencils being fixed across the end of the tube and inside in any suitable
manner.
In the drawing the end of the tube is made to take the shape of a cup fitting
freely and held up by means of a universal joint to that portion attached to the
bottom of the instrument, or any other suitable position. P indicates the pencils
or moveable contacts B B the blocks in which they rest and T the tube. The
other parts will be clearly understood from the drawing. The tube is shewn with
the end broke away but it is in practice provided with a mouthpiece the same as
any ordinary speaking tube. The screw cup S may be screwed directly on to the
base A of the instrument if preferred or in other suitable manner.
With reference to Fig. 4. we sometimes prefer to double wind. the primary coil
and so continue the separate circuits round the induction coil and separately back
to the batteries or the primary coil may be double wound and joined together for
'quantity" reducing the resistance of the primary circuit on
the coil say
about 75° And we also find that it is a great advantage to double wind the
secondary coil and join the two wires for quantity which also of course reduces
the resistance of the secondary coil say 75% and reduces the retarding effect of
the extra currents in the induction coil considerably but this is not claimed as part
of our invention.
Fig. 6. is a vertical cross section of the tongue receiver a is the cylinder or
recess or air 'chamber, b the plate or tongue of pine ebonite or any other suitable
material before referred to screwed or secured inside and at the base of the
instrument at A and free at the top (or it may be clamped or screwed at the top
and be free at the bottom as may be preferred) e is the armature attached to
the tongue or plate b and projecting through an orifice in the cylinder or recess.
The other parts will be understood Al being the magnet I the coil and TT the tubes
for conveying the sounds to the ears. We prefer to use a horse shoe magnet with
this form of receiver.
Fig. 7. is a vertical cross section of the combined transmitter receiver and relay.
ais the cylinder or recess as before the tongue preferably of pine screwed or
clamped, at A-C is a small bracket or support holding the cylinder to the base B
of the instrument case BB are the carbon blocks holding one end of the carbon
pencils or other moveable contacts and attached to the free end of the tongue b.
R. R' are small shuttors so that the microphone may be readily got at The
sounds reproduced by the instrument as a receiving telephone are conveyed to the
ears by the tubes TT and as the vibration of the tongue also sets the pencils in
vibration in unison with the tongue and this varying the current flowing through
the primary circuit of the induction coil assists and augments the effective strength
of the current from the line by inducing corresponding undulations in the secondary
coil equivalent to the vibration of the tongue which caused them. The operator
using the instrument as a Transmitter can speak down either of the same tubes
used for listening. The vibration of the armature in front of the magnet when
transmitting also induces a current in the coils on the end of the magnet and so
increases the effect of the instrument as a transmitter and having now fully
described our invention and the best modo known to us of performing the same
we would bayo it understood we do not claim broadly the dispensing with

page_text: a diaphragm to support microphonic contacts, but what we claim as our
invention is:-
Firstly. The application of microphonic pencil or like contacts fixed or placed
across the end or inside of and in. combination with a tube trumpet or
trumpet mouthed case to form a telephone transmitter, thus dispensing
with a diaphragm in the manner substantially as described and
Secondly. The improvement on the vibrating tongue receiver described in our
former Letters Patent consisting of the use of a tongue or plate of pine or
like resilient non-inductive material screwed or clamped at one end and
free to vibrate in the recess or air-chamber when acted on by an electro-
magnet and in combination with the said recess or air chamber
substantially as described and illustrated.
illustrated.
Thirdly. A telephonic instrument constructed with a free tongue or plate of non
inductive material (and to which microphonic pencil contacts are attached)
and actuated by an electro magnet in such manner that the whole forms
a combined transmitter, receiver and relay, substantially as described and
illustrated.
In Witness whereof we the said George Henry Bassano Albert Edward Slater and
Frederick Thomas Hollins have hereunto set our hands and seals this thirteenth
day of February in the year of our Lord 1884.
GEORGE HENRY BASSANO
ALBERT EDWARD SLATER
(L.S.)
(L.S.)
FREDERICK THOMAS HOLLINS (L.S.)