IMPROVEMENTS IN AUTOMATIC SWITCHES FOR TELEPHONES AND OTHER ELECTRICAL APPARATUS
Year: 1879

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
AUTOMATIC SWITCHES FOR TELEPHONES AND OTHER ELECTRICAL APPARATUS."
A communication from abroad by Edwin Trueman Greenfield and Daniel
McLean Adee, both of Brooklyn, in the County of Kings, State of New York,
United States of America.
Sealed the 11th June 1880, and dated the 31st December 1879.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 31st December 1879.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN AUTOMATIC SWITCHES FOR
TELEPHONES AND OTHER ELECTRICAL APPARATUS." [A communication fron
abroad by Edwin Trueman Greenfield and Daniel McLean Adee, both of Brooklyn,
in the County of Kings, State of New York, United States of America.]
The object of this Invention is to provide for an automatic switch a movable
electric or magnetic conductor that by its own gravity shall make or break
magnetic and electric connection.
The Invention consists in a movable electric or magnetic conductor formed of
quicksilver, metallic sand, or shot, or the like placed in a tube or cylinder of metal,
glass, rubber, or other material, but preferably of metal that is fitted with electric
connections, so that a change in the position of the said tube or cylinder shall
cause the quicksilver, metallic shot, or other conductor moving by its own gravity
to make or break contact or connection between two electrodes.
For the purpose of illustration the device will be described as applied to a
telephone. The telephone case is provided with the usual binding posts fixed on
its cap. The tube or cylinder which contains the quicksilver or other conductor is
furnished with a plug of non-conducting material placed in the bottom of the
cylinder and communicating with the interior, which plug insulates an electrode
which passes through it and connects by means of its binding post with the ground
wire. A cone is screwed into the top of this metallic cylinder, said cone being
composed of alternate rings or layers of rubber or other non conducting substance,
and of metal or other conducting material, held together by a screw passing through
them, but not in contact with the metallic rings. The metallic rings serve as
electrodes. The quantity of quicksilver, iron, sand, or shot, or other self moving
electric conductor placed in the cylinder, is such that it will extend up from the
bottom of the cylinder cavity to the end of the cone, and in contact with the

page_text: nonconducting ring when the telephone is in an upright position. A wire which is
attached to the cylinder by a metallic screw is connected with the line or local
battery wire by its binding post, so that through the cylinder connection is
established between the local battery wire and the ground wire, but no connection
exists between these wires and the metal rings or electrodes of the cone while the
telephone or cylinder is in the upright position, but if the cylinder be placed in an
inclined position the movable conductor is by its own gravity so moved as to make
connection between the cylinder and the electrodes of the cone, so that the electric
current shall pass from one of these electrodes through a wire to the coil or spool of
the telephone, and by another wire to connect with the ground wire, while the
electric current also passes from the other electrode of the cone to a wire which
connects by a binding post, and thence through the local battery wire to the
transmitter.
The movable electric conductor may also be applied in a tube of glass or other
non-conducting material tipped with platinum foil or other good conductor, and
having bands of the same metal around it Wires which pass through perforations
in the tube connect with these bands and with the foil or other conductor on the
tip of the tube. This tube so arranged is set within a larger tube so that a
perpendicular line may be drawn through their axes. A wire projects from the
point of the outer tube, and within this tube the movable conductor (in this
instance quicksilver) is placed in such amount that it will extend up from the point
of the tube and come in contact with the electrode on the tip of the inner tube
when the telephone is in an upright position, and thereby make connection between
this band or electrode and the wire connected at the point of the outer tube.
When the telephone is placed in a horizontal position the movable conductor by
its own gravity so moves as to break connection between the electrode on the tip
of the inner tube and the wire at the point of the outer tube, and establishes
connection between the three bands or electrodes on the inner tube. For example,
when the telephone is in an upright position the electric current passes along the
main line to its binding post on the cap of the telephone, thence to the line
connection or electrode through the movable conductor to the ground wire, thence
through the ground wire to its binding post, and to the bell to sound it, the bell
being kept in circuit so long as the telephone remains in this upright position, but
when, in order to use the telephone, it is held in an inclined position the circuit
between the main line wire and the ground wire becomes broken by the moving of a
the conductor, while the connection between the main line and telephone wire that
connects at one of the bands or electrodes in the inner tube, and the local battery
wire that connects at the other band, is established, and the current passes through
the line wire through the electrode on the point of the inner tube to the conductor,
thence through one of the bands or electrodes to the telephone wire through the 4
spool or coil to binding post, and thence to the ground, or if there be a transmitter,
through that to the ground. At the same time the local current is thrown through
the line wire, the electrode on the point of the inner tube, and the conductor to the
other band or electrode, thence to a binding post through the transmitter (if a
transmitter be used), to the other pole of the battery. If a transmitter be not used
the latter electrode is dispensed with.
This electrode or magnetic movable conductor in combination with the electrodes
on the inner tube and ground wire forms a perfect automatic electric switch. It
is especially designed for use with the telephone, but it can be applied as a circuit
maker and breaker in any connection where electric switches are used, and as its
action is governed solely by gravity it is more efficient, more easily operated, more
durable, and more certain of action than are those switches that are operated by
springs.
It is evident too that this switch is not liable to get out of order, because it is
protected from the corroding influences of weather by the containing tube.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the 30th
June 1880.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN AUTOMATIC SWITCHES FOR TELEPHONES AND
OTHER ELECTRICAL APPARATUS." A communication from abroad by Edwin
Trueman Greenfield and Daniel McLean Adee, both of Brooklyn, in the County of
Kings, State of New York, United States of America.
The object of this Invention is to provide for an automatic switch a movable
electric or magnetic conductor that by its own gravity shall make or break magnetic
and electric connection. The Invention consists in a movable electric or magnetic
conductor formed of quicksilver, metallic sand, or shot, or the like, placed in a tube
or cylinder of metal, glass, rubber, or other material, but preferably of metal that is
fitted with electric connections, so that a change in the position of the said tube or
cylinder shall cause the quicksilver, metallic shot, or other conductor moving by its
own gravity to make or break contact or connection between the electrodes. For
the purpose of illustration the device is shown in the Drawings as applied to a
telephone.
Figure 1 is a vertical sectional clevation of a telephone, showing the switch
applied in a cylinder of iron or other conducting material; Figure 2 is an enlarged
sectional elevation of the switch applied as above; Figure 3 represents the said
switch in a horizontal position; Figure 4 is a vertical sectional elevation of a
telephone, showing the switch applied in a cylinder of glass or other non-conducting
material; Figure 5 represents the same placed in a horizontal position; Figure 6
is a plan of the telephone. Similar letters of reference indicate corresponding parts
in the various Figures.
A represents the telephone case provided with binding posts 1, 2, and 3, that are
fixed on its cap C; D is a tube or cylinder of iron or other conducting material,
through the bottom of which and communicating with its interior is a plug u of
non conducting material, which plug a insulates the electrode b which passes
through it, and which electrode 6 connects by means of the binding post 1 with
the ground wire c. Screwed into the top of this metallic cylinder D is a cone E
composed of alternate rings or layers of rubber or other non-conducting substance d
and metal or other conducting material f, h, which rings or layers are held together
by a screw g passing through them, but not in contact with the metallic rings.
These metallic rings serve as electrodes. Within the cylinder D is placed a small
quantity of quicksilver, iron, sand, or shot, or other self moving electric conductor F,
in such an amount that it will extend up from the bottom of the cylinder cavity to
the end of the cone E, and in contact with the lower non-conducting ring d when
the telephone is in an upright position, as shown in Figure 1. A metallic screw i
binds the wire k to the iron cylinder D, which wire k is connected with the line or
local battery wire by the binding post 3, so that through the cylinder D connection
is established between the local battery wire and the ground wire, but no connec-
tion exists between these wires and electrodes h and f while the telephone or
cylinder D is in this upright position, but if the cylinder D be placed in an inclined
position, as shown in Figure 3, it is seen that the movable conductor F has by its
own gravity so moved as to make connection between the cylinder D and the
electrodes and f, so that the electric current shall pass from the electrode f
through the wire m, spool n, and wire o to connect with the ground wire c, while
the electric current also passes from the electrode h to the wire p, which connects
by the binding post thence through the local battery wire a to the transmitter.
In Figures 4, 5, and 6 is shown the movable electric conductor applied in a tube
of glass or other non-conducting material. In these Figures A' represents the
8

page_text: telephone case provided with binding posts 4, 5, and 6, that are fixed on its cap C¹.
D' is a tube of glass or other non-conducting substance tipped with platinum foil
or other good conductor a¹, and having bands b', c', of the same metal put around
it, and with these bands b¹, o¹, and a¹ wires are made to connect by passing through
perforations in the tube D¹. This tube D' so arranged is set within a larger tube E¹
so that a perpendicular line may be drawn through their axes, and from the point d'
of this tube E¹ also projects a wire, and within this tube E' the movable conductor
G' (in this instance quicksilver) is placed in such an amount that it will extend up
from the point d' of the tube E¹, and come in contact with the tip or band a¹ of
the tube D' when the telephone is in an upright position, as shown in Figure 4,
and thereby make connection between the band or electrode a' and the wire con-
nected at d. When the telephone is placed in a horizontal position, as shown in
Figure 5, it is seen that the inovable conductor G' has by its own gravity so moved
as to break connection between a' and ', and has established connection between
the bands or electrodes a¹, b¹, and c¹.
For example, when the telephone is in an upright position, as shown in Figure 4,
the electric current passes along the main line to the binding post 4, thence to
line connection or electrode a¹, thence through the movable conductor G¹ to the
ground wire m', thence through the ground wire m' to the binding post 6, and
thence to the bell to sound it, the bell being kept in circuit so long as the telephone
remains in this upright position, but when, in order to use the telephone, it is
held in an inclined position, the circuit between the main line wire / that connects
at a² and the ground wire m² that connects at d' becomes broken by the moving
of the conductor G', while the connection between the main line and the telephone
wire o' that connects at 6¹, and local battery wire p' that connects at c¹ is established,
and the current passes through the line wire , through the electrode a¹ to the
conductor G¹ through the electrode b¹ to the telephone wire o¹, and thence through
the spool n' to the binding post 5, and thence to the ground, or if there be a trans-
mitter through that to the ground. At the same time the local current is thrown
through the line wire l, thence through the electrode a¹, thence through conductor
G¹ to electrode c¹, thence to binding post 5, and thence through the transmitter (if
a transmitter be used) to the other pole of the battery. If a transmitter be not
used the electrode c* is dispensed with. This electrode or magnetic movable con-
ductor G¹, in combination with the electrodes a¹, b¹, c¹, and ground wire m', forms
a perfect automatic electric switch. It is especially designed for use with the
telephone, but it can be applied as a circuit maker and breaker in any connection
where electric switches are used, and as its action is governed solely by gravity it
is more efficient, more easily operated, more durable, and more certain of action
than are those switches that are operated by springs. It is evident too that this
switch is not liable to get out of order, because it is protected from the corroding
influences of weather by the containing tube.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the herein-
before in part recited Letters Patent is, -
1st. For making or breaking an electric or magnetic connection a movable con-
ductor whose position in relation to the electrodes may be changed by its own
gravity, substantially as herein shown and described.
2nd. In an electric switch a gravitating conductor in combination with one or
more electrodes, substantially as herein shown and described.
3rd. In an electric switch the metallic cylinder D provided with a nonconducting
plug a, electrode b, screw i, and wire k, substantially as herein shown and
described.
4th. The combination of the movable switch conductor F with the metallic
cylinder D, electrode b, screw i, and cone E, composed of non-conducting rings &
and conducting rings f, h, substantially as and for the purpose described.
5th. In a telephone the perforated tube D' provided with metallic bands or

page_text: electrodes a¹, b, c, in combination with the main line, telephone wires, and local
battery wires, o', p', respectively, substantially as and for the purpose described.
6th. In a telephone the tube E' enclosing the electrodes a³, b', c', and carrying
the ground wire m³, substantially as and for the purpose described.
7th. The combination of the movable switch conductor G' with the tube E¹,
electrodes a³, b¹, c¹, and wires l', m³, o', p', substantially as and for the purpose
described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twenty ninth day of June, in the year of our Lord
One thousand eight hundred and eighty.
A. M. CLARK. (L.S.)