IMPROVEMENTS IN TELEPHONES
Year: 1882

page_text: LETTERS PATENT to Henry Bull Templer Strangways of Pump Court, Temple,
in the City of London, Barrister-at-Law for an Invention of "IMPROVEMENTS
IN TELEPHONES
»
PROVISIONAL SPECIFICATION left by the said Henry Bull Templer
Strangways at the Office of the Commissioners of Patents on the 7th October
1882.
HENRY BULL TEMPLER STRANGWAYS of Pump Court Temple in the City of
London, Barrister-at-Law "IMPROVEMENTS IN TELEPHONES"
"
The object of this invention is to increase the efficiency of telephones whether
used as transmitters or receivers.
To this end the invention consists in the endway reciprocation or vibration of a
small magnet or bar of metal capable of inductive action arranged in line with
another magnet or piece of metal, the said small magnet or bar being attached to
a diaphragm of any material capable of rapid vibration and a solenoid or a coil of
wire surrounding one or both of such magnets.
According to my invention the diaphragm or tympan, may be of metal, wood,
glass or any other material which is capable of vibrating in response to the varying
electric currents received by, or the varying magnetic force, set up in the apparatus,
or of vibrating in response to sounds which may reach such diaphragm or tympan.
The whole of this small magnet or small piece of metal vibrates with the diaphragm
or tympan to which it is attached, and is of such small size and weight as will not
unduly check or impede the vibrations of the diaphragm or tympan.
It is also
desirable that such small magnet or piece of metal should at the point of contact
with the diaphragm or tympan be as small as will permit of its secure attachment.
This invention does not relate to a plate of metal attached to a diaphragm or
tympan as in Bell's original telephone, or to a diaphragm or tympan attached to one
leg of a horse-shoe magnet, as in Theiller's telephone, and in such latter case actuated
by the lateral vibrations of the leg of such horse shoe magnet.
In my invention the magnet or piece of metal as aforesaid is preferably in the
shape of a short bar of small diameter, a piece of iron wire N° 9 B. W. G. from t
to of an inch in length answering admirably. This short bar is attached
Pris G71

page_text: preferably by one extremity to the approximate centre of the diaphragm or tympan,
and in the telephone in addition to the ordinary magnet with a wire helix on the
end thereof I add a second wire helix which surrounds the aforesaid bar or small
piece of metal attached to the diaphragm. This additional coil or helix is attached
to the telephone case and has an aperture in the centre through or within which
the said small bar or piece of metal can move freely. This additional helix or coil
is fixed close to, or may be mounted on and attached to, and is in connection with
the helix on the polar extremity of the principal magnet.
The diaphragm with the small bar or piece of metal attached is fixed to the
telephone case in such a manner as to permit the diaphragm or tympan to vibrate
freely without touching the helix, and without the bar or piece of metal which lies
within the additional helix or coil touching the same. It is not necessary that the
diaphragm or tympan should be secured to or rest upon the telephone case all
round its circumference, it is sufficient if it has three or more bearing points so as.
to keep it in its proper position. The wires on the two coils or helices are joined so
as to form practically one helix, or the current may be divided between the two or
the current may be sent through the two helices in different directions.
The mouth-piece having been put on, the telephone is complete except as to
adjustment. If now the extremities of the principal magnet and the aforesaid small
bar or piece of metal are in contact and the telephone is put in circuit with any
telephone transmitter scarcely any sound can be heard in the telephone, but if such
principal magnet and the aforesaid bar or picce of metal are separated by the
smallest space that is sufficient to permit the diaphragm or tympan to vibrate
freely without the principal magnet and the aforesaid bar or piece of metal coming
in contact, all sounds are clearly and loudly reproduced in accordance with the
electric impulses received from the transmitter. A small horse-shoe magnet may
be used instead of the small bar or piece of metal, and a small helix or solenoid coil
may then surround each leg such two small helices being properly connected in the
usual manner, If a horse-shoe magnet is used as the principal magnet one leg may
be bent round so as to surround, though without touching, such small magnet or
piece of metal as aforesaid, or to become opposite to, though without touching, the
end of the magnet bar or piece of metal which is attached to the diaphragm. A
telephone constructed in accordance with this invention may be used as a transmitter
or receiver only, or as both transmitter and receiver. If the diaphragm or tympan
is of large size two or more of these arrangements of magnets, bars or pieces of
metal and surrounding helices or solenoid coils may be used in connection with
such diaphragm or tympan. In any of these arrangements the principal magnet
may be either a permanent magnet or an electro magnet, and the small bar or piece
of metal may be a permanent magnet. The helix on the end of the principal magnet
or the second helix may for some purposes be dispensed with, though in such case
the articulation is not so satisfactory. When one of these, telephones is used as a
transmitter its sensitiveness may be increased by attaching the centre of the
diaphragm or tympan by a light rod, wire or string, to another and larger diaphragm
or tympan, and when used as a receiver the sound may be magnified in a similar
manner.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Bull Templer Strangways in the Great Seal Patent Office
on the 6th April 1883.
'
HENRY BULL TEMPLER STRANGWAYS of Pump Court; Temple in the City of
London, Barrister-at-Law "IMPROVEMENTS IN TELEPHONES
"
.
The object of this Invention is to increase the efficiency of Telephones, whether
used as transmitters or receivers, and it relates to the application to Electric
Telephones of certain novel means for increasing the electric effect of the action of
the diaphragm or other vibrators, and consequently the strength of the currents
produced in and transmitted by the instrument. And for increasing the electrical
effect of the varying currents upon the receiver, and consequently the volume of
sound produced.
It has been already proposed to fit to the centre of, the diaphragm or other vibrator
a small magnet of short bar of metal capable of inductive action, arranged in line
with another magnet or piece of metal capable of inductive action, and to surround
such small magnet with a solenoid or helix for the purpose of creating magnetism
of varying strength and polarity in such small magnet or piece of metal capable of
inductive action
In one example an intermittent reversed current from a battery passes from the
line wire through the solenoid surrounding the small magnet or piece of metal
capable of inductive, action attached to the vibrator or diaphragm, to produce the
desired result, an independent magnet being used in connection therewith.
In another case, the line wire is caused to throw into the said solenoid a varying
current in the reverse direction to that which is passing through the helix on the
principal magnet of the instrument.
According to my Invention I use two helices, but I send a current in one and the
same direction through both helices, and thus I act simultaneously, and in precisely
the like manner, upon the principal magnet and on the small magnet or piece of
metal capable of inductive action, obtaining thereby the sum of the two actions.
The result of this mode of applying the current is the production of larger electrical
effects and louder sounds, than were heretofore obtainable.
In the accompanying drawing I have shewn the means of carrying my Invention
into practical effect in three forms of telephonic apparatus.
Fig 1 represents a longitudinal section of a telephone receiver of the ordinary
type arranged to suit the purpose of my Invention. Fig: 2 is a longitudinal
sectional view of a telephone receiver, in which a horse shoe or two legged magnet,
instead of a straight bar magnet is used, and to which my Invention is applied;
and Fig: 3 is a sectional view of another form of telephone to which my Invention
is applied.
In all these figures the same letters of reference indicate like or corresponding
parts
Referring now to Fig: 1. A is the telephone case, within the handle of which is
fixed a permanent bar magnet B, having as usual, a helix or coil of insulated
wire C wound around a bobbin c. on its upper end, or that which is nearest to the
diaphragm D. To this diaphragm D, which may be made of wood or metal or any
substance capable of rapid vibration, is attached, by rivetting or otherwise, the
small magnet or short bar of metal d, capable of inductive action, and of such small

page_text: size and weight as will not unduly check or impede the vibrations of the diaphragm
or tympan, and of such small diameter that any transverse vibrations set up in
auch small magnet or piece of metal capable of inductive action shall not be of
sufficient strength to deaden or destroy the longitudinal vibrations set up in, or
imparted to, the said small magnet or piece of metal by the varying electric currents
or by the vibrations of the diaphragm or vibrator.
Though the dimensions may vary as the size of the other parts of the Telephone,
I have found that a piece of iron wire N° 9 B WG from one-quarter to three-
eighth of an inch in length answers admirably for this picce d. This small
magnet d. is preferably rounded off or reduced in diameter, at the part where it
touches the diaphragm D, to the smallest size consistent with its secure attachment
theroto..
The diaphragm D does not require to be attached to the case A all round its
periphery, as is usual, but may rest upon the heads of three or more screws a. a
which may, conveniently, for adjustment, have shoulders formed thereon to receive
the circumference of the diaphragm, and ensure its exactly concentric position with
respect to the case A, the magnet B, and the solenoids or helices in connection
therewith, or it may rest upon the case in three or more places.
Surrounding the small magnet or piece of metal d. is a second helix E of insu
Inted wire (the gaugo known as N° 36 B WG answers, well) which is wound
around a wooden bobbin a forined in one, or so as to be one, with the bobbin c. on
which the helix O is wound. The wire leading from the terminal G is wound so as
to form the two helices C and E, and it is then led to the terminal F. These
helices I so wind that the current will pass through.both in the same direction.
Instead, however, of passing the whole of the current through each helix in
succession, I may connect the two helices with the line wires, and thus split the
current, seriding one part through each holix; and if it is desired to further reduce
the resistance of the helices, they or either of them may be wound with two or
more wires, the current being sent through all in the same direction. The bobbin e
of the helix E is accurately turned and drilled at its centre to receive the small
magnet or piece of metal capable of inductive action d. attached to the diaphragm D,
and this hole is of such diameter as will just allow the piece d, to reciprocate freely
without touching the walls of the said bobbin c.
The diaphragm D is adjusted at such a distance.from the pole B' of the magnet B,
that the end of the small magnet d. when the diaphragm is vibrating, shall be as
close as possible to, though without. coming in contact with the end of the
magnet B.
The diaphragin D is held in place by the mouth or car piece A' of the telephone
case, which may be screwed down upon it so as to hold it all round, or so as to hold
it in three or more places, and the concentric adjustment of the diaphragin may be
effected by shifting its position with, the finger nail, or otherwise, before finally
screwing the mouth-piece down on the case, or securing the mouth-piece to the
caso by scrows or otherwise.*
It will be understood that on speaking into the mouth piece A¹ the diaphragm D
will be caused to vibrate, and the consequent endway movement of the piece d,
within the coils of the helix E, and in close proximity to the polar extremity of the
magnet B, will have the effect of greatly increasing the electrical currents produced
by the instrument and transmitted to the line wires. If on the other hand, the
instrument be used as a receiver, the variations in the electrical current passing
through the line wire, and around the coils C and E will cause the pièce d. to
receive a rapid reciprocation end wise, corresponding to such variations in the current
and thereby set the diaphragm D in action.
Fig: 2 shews a mode in which this Invention may be adapted to a permanent
horse-shoe or two-legged magnet B, when it is desired to utilize the inductive
influence of both legs. B is a pole piéco mado fast to one of the legs by a nut S,

page_text: and surrounded by the larger helix C: this pole piece B¹ may be made adjustable
in any of the well known ways.
The horse-shoe magnet is attached to the telephone case A by one leg, and the
other leg, which is situate in front of the small helix or solenoid E has a hole made
in it to allow the small magnet or piece of metal d. attached to the diaphragm D, to
enter the helix E without touching the magnet.
Fig: 3 represents a simple mode of adapting this Invention to the electro-magnet
telephone invented and given to the public by me some years ago, and described in
the Scientific Journals.
The diaphragm D, with its small magnet, bar or piece of metal d. is similar to
that shewn in Figures 1 and 2 and the case is similar to that shewn in Fig: 2.
The coil C is united to the coil E to form one continuous helix which is placed within
the galvanic circuit (an effective size for this helix will be three-quarters of an inch.
in diameter and three-quarters of an inch long) This single helix, C'E, is attached
to the case; and through the centre, at the end next the diaphragm, a hole is made
large enough and long enough for the small magnet, bar or piece of metal d. capable
of inductive action, and attached to the diaphragm D, to move freely therein.
Through the other end is made a hole slightly smaller in diameter, and a piece of
iron or steel rod or wire B is threaded and, screwed into the helix until it nearly
touches the magnet or piece of metal d. attached to the diaphragm D. This
threaded rod or wire B thus acts as a principal magnet, and as an adjusting
screw at the same time. I find that a piece of wire of the gauge known as N° 9
BW G answers well.
A telephone in this form may be made very small; one two inches in diameter
and one-and-a-quarter inches thick answers well, and if such a telephone is placed
on the polar extremity of a powerful magnet, the articulation becomes greatly
increased in strength.
A telephone made on this plan is, when the two rods or bars of metal are of
soft iron, excited and actuated entirely by the current in the main circuit or line
wire.
For some purposes the diaphragm D may be in the shape of a strip of metal, in
which case it is sufficient that it rests upon two points only or has two places of
support only, one at each end, point or side thereof.
A telephone instrument arranged on any of the above described plans may
be used either as a transmitter or a receiver only; or as both transmitter and
receiver.
In any of these arrangements the principal magnet B may be either a permanent
or an electro magnet, and the small bar or piece of metal d may be a permanent
magnet.
Having now set forth the nature of my Invention of improvements in
Telephones and explained the manner of carrying the same into effect, I wish
it to be understood that under the above in part recited Letters Patent I claim.-
First: In an electric telephone, the diaphragm or vibrator of which is furnished
with a small magnet or piece of metal capable of inductive action as herein before
described and a inain magnet opposed thereto, the helices C and E set concentric
with such magnets, and so connected with the line wires, that a current will flow
through them in one and the same direction, and act simultaneously, and in
precisely the like manner upon the two magnets, whereby the sum of the actions
produced by such currents upon the two magnets will be imparted to the diaphragm
or vibrator of the telephone, when used as a receiver; and when the telephone is
used as a transmitter, the sum of the actions of the two magnets producing or
affecting electric currents in the said helices will be transmitted through the line
wires, substantially in the manner and for the purposes hereinbefore set forth.
Secondly In combination with the above described arrangement of helix or
helices and small magnet or piece of metal capable of inductive action, a horse-shoe

page_text: or two-legged magnet, substantially as and for the purpose described with reference
to Fig: 2 of the drawing.
Thirdly The modification described with reference to Fig: 3 of the drawing for
the purpose set forth.
In witness whereof I the said Henry Bull Templer Strangways have hereunto
set my hand and seal the third day of April in the year of our Lord One
thousand eight hundred and eighty three
H. B. T. STRANGWAYS (L.S.)