Improvements relating to Mechanical Telephone Apparatus.
Year: 1886

page_text: Improvements relating to Mechanical Telephone Apparatus.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, 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 relates to that class of instruments known as mechanical
telephones, and is an improvement in systems for using or operating the same,
comprising means for connecting three or more of the instruments together in a
common system.
With the appliances heretofore devised it has not been practicable to transmit
speech by means of mechanical telephones except from one terminal to the other
of a line, so that any approach to a system of communication between a number of
different points, such as is found in the ordinary electric telephone systems would
involve such a multiciplicity of lines and instruments as to prevent the use of
mechanical telephones, except on isolated lines.
The object of this invention is to increase the capacity of a mechanical telephone
line, whereby three or more instruments may be connected to the same line and
messages sent from any one to another. The invention is particularly applicable
to localities where a comparatively small number of subscribers reside within a
short distance of one another, as in small towns or villages, and on account of its
applicability and usefulness in this respect it is called a Village Telephone
System."
In this case the system may be conveniently regarded as comprising a main and
branch lines. Communication between the terminals of the main line is effected
in the ordinary manner, that is to say, a string or wire is connected to the
diaphragm of the telephones and stretched and suspended so as to take up the
vibration produced in one and reproduce them in the diaphragm of the other.
The other instruments are not permanently connected in operative relation with
the main line, but means are provided for bringing one or more of them into such
relation at any time, and in this feature the invention resides. -
.

page_text: The invention may be carried out by many different devices. For example, at
any point on the main line where it is desired to take off a branch line, a flat iron
strip is inserted directly in the line and suspended by two or more strings or
wires. In close proximity to this strip is also suspended a flat V-shaped piece of
soft iron arranged so that its ends may come into contact with the strip on the
line. Both the strip, which is designated an armature, and the V-shaped piece
which is designated the magnet, are wound with an insulated wire which is in a
local circuit containing a switch located near the telephone of the branch line. By
closing this circuit, the magnet and armature are held in contact so that vibrations
in the main line are imparted to the magnet. If the latter form part of a local or
branch line it is obvious that the telephone therein will respond to the vibrations
produced in the main line.
Another way of accomplishing the same result is to use an electro magnet or
solenoid to overcome the pull of a spring that normally holds the end of a local
line out of mechanical contact with the main, and to include this magnet in a
local circuit which is closed when a person desires to use the telephone on the
branch line.
Since each branch line has normally no connection with the main line, it is
evident that a number of them may be used, and the above illustrations serve to
exemplify the principle of construction and mode of operation of the devices
constituting the invention.
The specific character of the invention will be described by reference to the
drawings, in which:-
Figure 1 is a diagram of the system showing the parts and devices in their
proper relations.
Figure 2 is a diagram of a somewhat modified form of the invention.
Figure 3 is a view of a detail hereinafter described.
A, A, in Figure 1 represents a mechanical telephone line with terminal instru-
ments B and B The character of the line and instruments is well known and
requires no further description, the latter being what are commonly known as
mechanical or "lovers' telephones" connected preferably by a light wire.
One branch line as C, is shown for purposes of illustration, it will be understood,
however, that others may be used, in which event their arrangement is in all
respects like that shown.
At the point where this branch is to meet the main line, a flat and comparatively
light strip of soft iron D is inserted directly in the main line and forms a part
thereof, the wire A being severed at that point and its ends connected to those of
the strip D. The strip D is preferably suspended by india-rubber bands or cords E,
or the like, from a stationary support. The introduction of this device in the line,
as is well known, has no sensible effect upon the transmission of speech over
the line.
On one side of the strip D and close thereto is suspended a flat V-shaped piece
of soft iron F. This is suspended by the bands or cords E, which connect with
the ends of the piece.. The piece F is included in the branch telephone line C by
severing the wire of said line and connecting its ends to opposite sides or corners
of the piece. The terminals of the branch line are connected, each to a telephone, or
one to a telephone, as F¹, and the other to a spring support hereinafter described.
Normally there is no connection between the two iron pieces D and F and the
telephone F¹ is in no wise affected by the operation of the line A. To bring the
telephone F¹ and its branch circuit into operative relation with the main line, so
that conversation may be carried on between either B or B¹ and F¹ or between F¹
and any other branch, the two pieces of iron D and F are wound with insulated
wire making them respectively an armature and magnet, but these coils should be
so made that they do not touch the pieces D, F but permit them to move freely
within the coils. An electric circuit G is also run from a point near the instru-
ment F1 and grounded through the coils on the magnet and armature. By closing
this circuit, the magnet and armature, being energized, are brought in contact and

page_text: adhere to one another so long as the circuit G remains closed. Under such con-
ditions the vibrations produced in one line will be imparted to the other and
the instrument F is thus brought into operative relation with either of the main
line instruments, or with any other branch instrument which may be at any time
connected with the main in a similar manner.
As above stated, the ends of line C may be connected to telephones. It is
preferable, however, to use but one instrument for each branch line and to connect
the other to a spring. This may be so arranged as to have at all times the same.
tension, or it may be modified. For example, the spring H is connected at one end
to a fixed support; at the other, to a pivotted bell-crank lever K. The end of
line C is connected to the same end or arm of this lever as the spring, so that
normally the full effect of the spring is exerted in maintaining the line under
tension. The other end of the bell-crank lever K carries the core L of a solenoid M,
which is included in the circuit G. When the circuit G is closed the solenoid
stretches the spring H and relaxes the tension of the line to a certain extent.
Under the action of the spring alone the line C is so taut as to hold the magnet F
away from its armature, but by relaxing this tension somewhat the contact of the
two is made easier.
With this system is employed an electric circuit with call bells of some kind.
This circuit N is represented as running to each telephone, at which it includes a
bell O. There are also provided keys or switches P with back contacts that
ground the line at its terminals and batteries R one with each switch, so that any
subscriber can call up any of the others. Any ordinary call or signal system may
be used for this purpose.
In Figures 2 and 3 a modification of the means for connecting the main line and
a branch is shown, all the other parts remaining the same as in Figure 1. In this
case line C carries a small disc or plate b rigidly secured to it. The line runs
through a slot in a metal plate T which is secured to the line A, or to a short
metal bar T¹ inserted in the line. The plate T is suspended by a cord or strap d
and may be of any shape.
The line C ends in a conical button e that fits in a countersink perforation in
the end of the bell crank lever K. A spring S is connected with this lever as in
the former case and the other end carries the core of a solenoid M in the circuit G.
Normally the strength of the spring S tightens the line C and holds the button
or disc b out of contact with the plate T, thus breaking the connection between the
main and branch lines. In order to operate the telephone F1 by either of the
telephones B or B¹ or conversely, the circuit G is closed. This draws the button b
into contact with the plate T and overcomes the tension of the spring S. In this
way the two lines A and C are so connected that vibrations in one are transmitted
to the other. It is important to observe that these and many similar devices which
may readily be designed from the above illustrations, effect more than a simple
contact of the two lines. The branch line in all cases is maintained at the proper
tension, its direction and relation being such with reference to the main that it
forms practically a continuation of the same.
From the examples given, of the way in which the invention is or may be
carried into effect, it will be seen that the underlying idea or principle of the
system is to bring two mechanical telephone lines into or out of operative relation
with one another at will, and secondly, to effect this by electrical agency.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign Correspondent, I declare that what I claim is :-
First. The combination with two mechanical telephone lines, provided with
couplings or mechanical connections for uniting the two lines, of means, sub-
stantially as described, for operating or controlling the couplings and thereby
bringing the lines into or out of operative relation with one another, as herein set
forth.

page_text: Second. In a mechanical telephone system, the combination with a main line
and one or more branch lines, of couplings or mechanical connections for uniting a
branch line to the main line, and means, substantially as described, for controlling
or operating the couplings and thereby bringing the branch line into or out of
operative relation with the main, as set forth.
Third. In a mechanical telephone system, the combination with a main and
branch lines, of a coupling or mechanical connection, the two parts of which are
connected respectively to the two lines, an electric circuit; and devices therein
adapted to be operated by the current and to control or operate the coupling and
thereby bring the two lines into or out of operative relation with each other, as
set forth.
Fourth. In a mechanical telephone system, the combination with a main and
branch lines, of an armature inserted in one line and a magnet in the other, and
placed or suspended in proximity to one another, and an electric circuit for causing
an attraction between the magnet and armature, whereby they are brought together
and the lines thereby connected at will, as set forth.
Fifth. In a mechanical telephone system, the combination with a main line and a
branch line, and means for mechanically connecting and disconnecting the same, of
a spring connected to the branch line for holding it taut, and an electric circuit
containing an electro magnet or solenoid acting in opposition to the spring, and
means for operating or controlling the connection between the two lines, as set
forth.
Sixth. In a mechanical telephone system, the combination with a main line, of a
branch line normally disconnected from the main, means for connecting the main
and branch lines, an electric circuit extending from the terminals of the branch line
to its point of connection with the main and devices included therein for con-
trolling or operating such connection, as set forth.
Seventh. In a mechanical telephone system, the combination with a main line,
of a branch line or lines, normally disconnected from the mains, means for con-
necting the main and branch lines, an electric circuit for each branch extending
from the terminus thereof to the point of connection with the main, devices
included therein for controlling or operating such connection, and an electric
signalling line running to all the telephones on the lines, as set forth.
Dated this 96th day of October 1886
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.