An Improved Telephone Combination.
Year: 1891

page_text: Date of Application, 27th Oct., 1891
Complete Specification Left, 20th July, 1892-Accepted, 20th Aug., 1892
PROVISIONAL SPECIFICATION.
An Improved Telephone Combination.
Sir CHARLES STEWART FORBES, Baronet, 11 Glendower Place, London, S.W.
East India Agent, do hereby declare the nature of this invention to be as
follows:-
The object of my invention is to simplify the construction of the ordinary
telephone combination, in such a manner as that while its acoustic effect can be
increased by a microphonic transmitter, the instrument may be used as an ordinary
magneto-telephone, without alteration, should the transmitter fail from any cause.
To this end I employ the same magnets which generate the current for ringing, to
produce a polarized condition of the core and tympan or plate placed near to, or
between the pole pieces forming part of the magnets or fixed thereto.
By the means just described, I am able to construct instruments of the fixed or
portable type, the ringing current being supplied by a magneto-generator, the
armature in which in the fixed instrument is operated by the well known wheel
gearing, but in the portable type is actuated by a plunger rack and pinion, or its
equivalent. In either case, I sometimes employ an ear trumpet or trumpets.
A variation of my invention consists in the employment of a cylinder within
which is mounted a T shaped pole piece forming part of or secured to one pole of the
magnets used for ringing. At both ends of the cylinder are secured adjustable
tympans, which are polarized by being mounted, so as to be in magnetic connection
with the other, and opposite pole of the ringing magnets. Ear trumpets are
mounted so as to convey the inflexions produced by the polarized plates, and a
suitable adjustment provided for regulating their distance from the interior pole,
which carries the bobbins, the wire on which connects to line and earth.
Communication by means of a tube may be made between the cylinder and the
box containing the microphone.
Dated Ontahon 07th 1001
FRANCIS M. ROGERS,
A gent
COMPLETE SPECIFICATION.
An Improved Telephone Combination.
Sir CHARLES STEWART FORBES, Baronet, 11, Glendower Place, London, S.W.
East India Agent, 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 :—
The object of my invention is to simplify the construction of the ordinary
telephone combination, in such a manner as that while its acoustic effect can be
increased by a microphonic transmitter, the instrument may be used as an ordinary
magneto telephone without alteration, should the transmitter fail from any cause.
To this end I employ the same magnets which generate the current for ringing,
to produce a polarized condition of the core, and tympan or plate placed near to or
between the pole pieces forming part of the magnets or fixed thereto.
By the means just described I am able to construct instruments of the fixed or
portable type, the ringing current being supplied by a magneto generator, the
armature in which in the fixed instrument is operated by the well-known wheel
gearing, but in the portable type is actuated by a plunger rack and pinion or its
equivalent. In either case I sometimes employ an ear trumpet or trumpets.

page_text: A variation of my invention consists in the employment of a cylinder within
which is mounted a T shaped pole piece forming part of or secured to one pole
of the magnets used for ringing. At both ends of the cylinder are secured
adjustable tympans which are polarized by being mounted, so as to be in magnetic
connection with the other and opposite pole of the ringing magnets. Ear
trumpets are mounted so as to convey the inflections produced by the polarized
plates, and a suitable adjustment provided for regulating their distance from the
interior pole, which carries the bobbins the wire on which connects to line and
earth. Communication by means of a tube may be made between the cylinder
and the box containing the microphone.
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To enable my invention to be clearly understood. I will now
particularly describe the same by the aid of the accompanying drawings, in
which :-
Fig. 1, is a part sectional elevation of a combined telephone and magneto
machine having but one tympan.
Fig. 2, is a plan, the top of the case being removed.
Fig. 3, is a general view, to a reduced scale.
Fig. 4, is a front view of cylindrical form, having two tympans, part being in
section.
- Fig. 5, is a plan, the top of case being removed.
Fig. 6, is a vertical sectional view, shewing modification of screw adjustment.
Fig. 7, is an enlarged view of T shaped extension.
Referring to the drawings-1, Figs. 1, 2, is the lid of the wooden or other box or
case 1º, 2 is a trumpet-shaped mouthpiece formed of any suitable material, such as
wood, ebonite or metal, this may be attached to the case 1, by screws 3, or by
glueing or like means. Mounted upon the inside of the door of case is a thin sheet
of pine or other soft wood 4, and to this the microphone 5, is attached. I lay
no particular stress upon the form of microphone shewn, since any of the well
known efficient forms may be advantageously used in combination with the devices
now to be described. Secured to the case by bolts 6, are the ringing magnets.
These I prefer to construct of suitable steel bars 8 say in. by in., and of
Suffieient length, I find 6 such bars, 3 on either side a convenient number to use
but I do not bind myself to such number, as more or less may in some cases be
employed with advantage, depending upon the effect required from the instrument.
The lower end of these bars are fitted with cast or wrought iron pole pieces 9, and
within these.revolve when actuated by any of the well known devices such as a
spur wheel, or disc 91, engaging with a suitable pinion 91, upon the axle 10, the
Siemens armature 11, employed for ringing. The upper end of each set of
magnet bars 8, are secured preferably by screwing to two pole pieces 12, 12',
formed of best soft wrought iron carefully annealed after tooling, one pole piece
is fitted with a square shaped soft iron adjustable extension 13, passing through
the pole piece 12 and upon. which a fine thread is cut, two soft iron lock nuts 14.
having a milled edge being threaded thereon which serve to clamp the polar
extension 13 to the pole piece 12, and adjust the same to the required distance
from the metallic tympan 14', a portion of the square edge of the extension is
turned down and its end rounded and upon this the bobbin 15, is mounted.
Secured to the opposite pole-piece 121, by screws 17, is a metallic box 16, prefer-
ably of brass, but it may be formed of any other suitable material. The front part
is turned faced and fitted with a screwed ring 18, which clamps the tympan 14'.
A long soft iron screw 19, fitted with a screwed washer 21, passes through a tapped
hole in the pole-piece 12', and carries near its extremity a bobbin 15', both
bobbins 15, 15, are filled with insulated wire 22, of suitable size for producing
the required effect; the wire upon each bobbin is joined in series or parallel,
passed through insulated holes 23, bored in the box 16, and connected for long
distances to the secondary wire of the induction coil 24, but for short distances it 5
may be joined in series with that leading from the microphone 5, or the microphone
may be left out and the ends of the wires upon the inducing bobbins joined

page_text: respectively to line and earth. The back of the box 16, is formed or fitted with
two elbows 25, which conduct the sound waves set up by the tympan 14', to the
ear by means of the flexible tubes 26, having trumpet ends 27, which are employed
for operating the switch lever 27¹. The operation of this first part of my inven-
tion will be readily understood. By means of the compound ringing magnet formed
as described, I am able to concentrate a very powerful magnetic field upon the
points of the soft iron extensions 13, 19, adjacent to the tympan, with the result
that loud articulate speech is obtained as a simple telephone; which is greatly
augmented if the microphone 5, or any equivalent reliable form actuated by a
battery is included in the circuit, or when such microphone forms part of a closed
but variable circuit with the primary wire of the induction coil 24, the secondary
wire being coupled in series with that upon the inducing bobbins in the manner
well understood. If desired, one inducing bobbin only may be used, in which
case the extension piece 19, has the effect of polarizing the tympan plate 14.
The intense field maintained between the extensions 13, 19 has the effect of
practically forming a closed magnetic circuit similar to that obtained by the use
of horse-shoe magnets, consequently when the armature 11 is revolved between
the polar pieces 9, at the reverse end of the magnets 8, ringing can be accomplished.
over long distances.
A variation of my invention consists in the employment of two distinct tympans
enclosed within a metallic or other cylinder, both tympans being inductively acted
upon by an enclosed T shaped extension mounted upon one of the magnet poles,
the other pole being so constructed as to polarize them-see Figs. 4, 5, 6, 7,
wherein 1, is the lid of the case 1ª upon this is mounted by screwing or otherwise a
square or round box a, see dotted lines, having a mouthpiece 2, containing the
microphone 5, which may be of any suitable form, and is mounted either upon
a metallic or wooden tympan 4, and secured by screws to the lid of case or in
any other convenient manner.
Secured to the case 1, by the bolts 6, are the steel magnet bars 8, say in.
by and I find 3 such bars on each side of the magnet a convenient number
for my purpose, but any number may be employed. The lower end of these
bars are fitted with cast or wrought iron pole pieces 9, cored or bored out so as
to receive a Siemens or other armature 11, of the well known type which is
employed for ringing the alternating bell b, as well as that at the distant end of
the line when required.
The upper end of the magnet bars 8, are secured by screwing or riveting to the
two pole pieces 12, 12', one of which 12', carries a T shaped soft iron extension 13,
see also Fig. 7, the shank of which is of square section and passes through a
corresponding hole formed in pole piece 121 a screw being formed upon the
extreme end upon which a milled clamp nut 14, is threaded. Upon either side
of the T shaped extension are inducing bobbins 15, 15, which are filled with
insulated wire 22, of suitable size joined up in series or parallel, the ends passing
out through an ebonite plug 23¹ to the secondary wire of induction coil 24, and
the line terminal. The two tympans 14' which are made of thin ferrotype plate,
each clamped by a screwed ring 28, into a recess formed in the soft iron cups 29,
which are each fitted with a raised ring 30, milled on its edge. The outer ends
are screwed into two rings 31, forming part of the soft iron pole piece 12, secured
to the three magnet bars 8, these rings have the effect of polarizing the
tympans 14'. Holes 32, are bored in the ends of each cup, and into these are
fitted the ferrules 25', screwed into plates 25", let into the woodwork of case.
The ear tubes 26, are. fitted to the ferrules 25'. The trumpet ends 27, being
employed to depress the switch lever 271 when the telephone is out of use as
described already. The instrument is fitted with a magneto bell, and switching
device whereby the line may be put into communication with the telephone or
bell as may be required. The switch I prefer to use is shewn in Fig.
and by
lotted lines in Fig. 4, and consists of a T shaped bar 28 passing through a
guide 33, and a plate 34, secured by screwing to the case, a collar 35, is formed

page_text: upon the bar and surrounding it is a spring 35¹. In Fig. 4 a spring is also
shewn at the end of bar 28.
The outer end of bar 27' which is pivoted to bracket 34 carries two forks 36,
in which the trumpet ends 27, of the air tube 26, are placed when the instrumept
is out of action, the effect of which is to put the line wire into connection with
the bell b, and generator by means of the springs 37, 38 and earth terminal 38",
in this position the upper springs 39, 40, 41, are out of contact with the T shaped
bar 28. When however, it is desired to speak, the ear tubes are lifted out of the
forks 36, the spring 351 re-acts cutting out the bell, closing the local battery circuit
through terminals 42, 43, the microphone and primary wire x, of the induction
coil 24, by the springs 40, 41, and connecting the telephone to line by spring 39,
terminal 44, in the manner well understood. In some cases I find it more con-
venient to adjust the tympans as shewn in Fig. 6. The flanged ends of the
cylinder 16, are in such case screwed, a piece of rubber or other suitable packing
inserted and a corresponding thread cut upon the inner portion of cup 29, the
outer end of which is turned to fit the polarizing rings 31. By turning the
cups the tympans 14' are adjusted to the requisite distance from the T shaped
extension 13.
The instrument now described may be used as both sender or receiver without
the aid of either microphone or induction coil, in which case a hole k, is bored
in the side of cylinder, as see Fig. 5, and a trumpet mouth-piece L, screwed into
a plate upon the outside of case, by speaking into this the sound waves are
deflected against the tympans and a corresponding variation produced in the line
and distant instrument, the ear trumpets being used for receiving the message.
If desired the microphone may also be used in series with the coils upon the
bobbins, with good effect.
When my improvements are embodied in a portable form suitable for short
distances, the respective parts are of a lighter character, to avoid the necessity for
case and complicated switching gear, the alternate current bell being also
separate therefrom. In such case the disc or spur wheel replacing it may be
dispensed with, a rack actuated by a plunger sufficing to produce the required
current for the bell.
One pair of permanent bar magnets may replace the compound set shewn and
described if more convenient.
I am aware that telephonic apparatus bas been described in which the horse-
shoe magnets employed for ringing, or extensions or pole pieces fitted thereto
(either form carrying inducing bobbins) are, in combination with a metallic tympan
or a tympan formed of magnetic material used for transmitting speech; but I do
not broadly claim such a combination. Although for the purposes of description
I have shewn a microphone mounted up in connection with my invention I do not
claim the form shewn, nor do I lay claim to the switching device described, or the
connections therefrom to the various parts of the instrument by themselves.
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. The combination and use of the compound permanent bar ringing magnets
having soft iron pole caps, with a metallic or other tympan box supported by one
or both of said magnets, having a tympan or tympans, and the adjustable polar
extensions or one of them carrying an inducing bobbin or bobbins so mounted as
to produce a polarized condition of said tympan, and a nearly closed magnetic
circuit. The same magnets being used for ringing the bell, and obtaining speech when
actuated by suitable switching gear substantially in the way and manner described.
2. In a telephone combination, the particular combination and arrangement of
parts whereby one end of a set of compound permanent bar magnets supplies
the current for ringing, and the other end is employed for producing speech by the
means, and in the way and manner set forth.

page_text: 3. The combination in or with a telephone depending for its magnetism upon one
end of the compound magnets employed for signalling, of the circular rings 31,
supporting the soft iron polarizing and adjusting cups 29, shewn and described
under Figs. 4, 5, 6.
4. The combination in or with a telephone depending for its magnetism upon
one end of the compound magnets employed for signalling, of the modified form of
polarizing cups and adjustment for tympans, shewn in Fig. 6.
5. The combination in or with a telephone deriving its magnetism from the
reverse end of the same compound magnets which operate the alternating bell, of
the perforated cylinder 16, and trumpet mouth-piece L, secured to the lid
of the case for speaking direct, substantially as shewn and described under
Fig. 5.
6. The combination in or with a telephone deriving its magnetism from the
reverse ends of the permanent magnets to that used for producing the ringing
current of a microphone, transmitter, induction coil, and an alternate current bell
operating by switching gear in the way and manner described.
Dated T 90th 1000
FRANCIS M. ROGERS,
Agent.