An Improved Telephone Switch.
Year: 1887

page_text: [Communicated from abroad by CHARLES A. HITCHCOCK, of North East, in the
County of Erie, State of Pennsylvania, United States of America, Engineer.]
An Improved Telephone Switch.
I, SAMUEL SIDNEY BROMHEAD of 97 Newgate Street, London, Patent Agent
(a communication), 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 present invention relates to that class of telephone-switches in which a hooked
lever supports the receiver or hand telephone, in such manner, that a movement of
the lever in one direction by the removal of the receiver, disconnects the call-circuit
from the main line, and connects with the latter the receiver and secondary circuit of
the transmitter, and at the same time also completes the primary local circuit of the
transmitter while a movement of the lever in the other direction, by the weight of the
receiver, cuts out the latter and the secondary circuit of the transmitter and restores
the call-circuit.
The object of the invention is to provide a switch mechanism which is reliable
durable and simple in construction, and in which the liability of the corrosion or
destruction of the electrodes or contact points is effectually prevented.
Another object is to improve upon the construction and arrangement of a telephone-
switch system in which fixed mercury contact-cups are combined with electrodes
carried by a movable bar, operated by a lever.
To these ends the invention consists in the construction and arrangement of devices,
which will be hereinafter more fully described, and then set forth in the claims.

page_text: signal box having the switch mechanism in position for bringing the local battery,
transmitter, and receiver in line-circuit. Fig. 2 is a diagram view representing the
arrangement of circuits, but, for the sake of clearness, not showing the special form of
contact devices which constitutes my invention and are thrown into action by the
switch-lever.
Fig. 3 represents one form of switch system embodying my improvement.
Fig. 4 shows another form the reverse of Fig. 3.
Fig. 5 is a section on line xx Fig. 4.
Fig. 6 perspective view of mercury contact-cup.
Fig. 7 sectional view of Fig. 6.
The reference numeral 1 designates a telephone signalling or call-box, which
contains the ordinary magneto-electric generator 2 and the customary binding posts
for making connections with the various circuits, hereinafter referred to.
The cover
or door 10 of the box carries the switch mechanism which constitutes my invention
and the ordinary bell or annunciator devices 3.
The
The switch mechanism comprises an horizontal lever, 4, having its outer end
shaped into a hook, 4 a, and its inner end fitted into a recess in a vertical bar, 5.
The lever is fulcrumed at or near its middle, as is seen at 6, and it moves between
stop-pins 7 on a bracket or plate, 8, fastened to the inner side of the door 10 a.
object of these pins is to limit or define the degree of movement of the lever, and a
spring, 8 a, bearing upon the same, serves to hold the lever in contact with the lower
stop-pin when a weight in the shape of the ordinary telephone-receiver is not applied
to the hook on the lever.
In
The spring 8a may be of any desired form, but for the sake of strength and
cheapness it is made of bent wire, and is curved so as to have one of its legs bear
upon the lever while the other leg is secured to the bracket 8. The vertical bar 5 is
fitted in loops or bands 9, and is capable of moving up or down in the same.
place of said loops we may resort to guide-pins passing through slots in the bar 5 for
guiding the movement of the latter. The function of the bar 5 is to make and break
different circuits belonging to an organized telephone system, the movement of the
bar 5 being effected by taking the receiver off from the hook 4 a or hanging it
thereon. The bar 5 carries the electrodes or wires 10, 11, 12, and 13, which co-
operate in connection with mercury contact-cups 14, 15, 16, and 17, arranged in
juxtaposition to the bar 5, in the manner clearly shown in Fig. 1. These mercury-.
cups are preferably made of wood, porcelain, or other material not liable to be affected
or corroded by a conductive filling of amalgamated mercury or composition of tin
and mercury. The various cups are each fastened to a small plate or support, 24,
which is connected by a pintle and eye to a second plate, 25, secured to the door 10 a.
By such means the mercury-cups can be set into an upright position when in use, as
is shown in Fig. 1, or they can be turned horizontally, or at right angles to the door,
for discharging their contents.
line circuits of a
The mercury-cups above referred to are in constant metallic connection with the
wires 16 a 17 a 18 a, are respectively included in the transmitter, receiver, and
telephene system. The wires 16 a are connected with the
hinges 19, the wire 18 a with the hinge 20, and the wire 17 a with the hinge 21,
and all these hinges are in their turn connected with the out and ingoing portions of
the transmitter, receiver, and line-wires, as is seen in Fig. 1. When the weight of
the receiver is taken from the hook 4a, the spring 8 a tends to throw the inner end
of the lever 4 against the lower stop-pin, 7, thus moving the bar 5 downward in its
guide-loops and bringing the electrodes or wires 10, 11, 12, and 13 into metallic
connection with the mercury-filling of the contact-cups 14, 15, 16, and 17, and in
such manner closing the transmitter, receiver, and line-circuits and permitting
télephonic communication to be had with a distant station.
We have indicated the different circuits in the diagram Fig. 2, omitting, however,
from the latter the special form of mercury contact-devices and the means for bringing

page_text: the latter in and out of action. When the receiver is applied to the switch-lever, its
weight serves to bring the latter against the upper stop-pin, 7, and the bar 5 is elevated at
the same time for throwing the battery transmitter and receiver out of line circuit,
such result being effected by moving the electrodes 10, 11, 12, and 13, out of contact
with the mercury-filling of the different cups. When the above circuits are broken,
the magneto-electric generator and call-bell are brought into line-circuit by means of
an auxiliary lever, 30, which is fulcrumed at its center, as is shown at 31, and has a
tenon or point fitting into a gain or notch, 32, in the bar 5, so as to be vibrated by
the movement of said bar. The lever 30 carries an electrode or wire terminal, 35,
adapted to dip into the mercury-filling of the cup 36, the latter being in constant
metallic connection with the wire 37, extending to the magneto-electric generator and
ground, the connection between the door and box being through the hinge 22. A
wire 38, extending from the electrode 35 through the bell-coils passes to line, the
connection being through a metal strip, 40, and hinge 20. The cup 36 is fastened to
a hinged-plate, 24, in the same manner as the cups included in the other circuits.
It has been demonstrated that by using mercury contact-cups and electrodes, as
above fully described, the different circuits are reliably made and broken, and the
corrosion or oxidation of the electrodes is effectually prevented, since the wires or
electrodes are not affected by the amalgamated mercury-filling of the cups.
It should be observed that the levers of the switch mechanism are preferably made
of wood or hard india-rubber; but any other non-conducting material may be used
for the same.
I will now refer to, and describe another part of my invention relating to a
telephone switch-system, in which fixed mercury contact-cups are combined with
electrodes carried by a movable bar which is operated by the lever upon which the
telephone-receiver is hung; and of improvements relating thereto to attain greater
simplicity and a perfect operation of parts.
The following reference-numerals all relate to Figs. 3, 4, 5, 6 and 7.
The reference numeral 1 x designates the door of a telephone-transmitter casing,
which contains the usual appliances of a local telephone system. A horizontal
lever 2, terminating in an end hook, 3 x, serves as a support for the hand-telephone
or receiving instrument. This hooked lever may be pivoted at the end opposite the
hook, as is seen in Fig. 3, or the pivot is removed to a point near the middle of the
lever, as is shown in Fig. 4. The lever moves up and down in a guide or keeper, 4 x,
and a spring, 5r, serves to hold it in an horizontal position or at the top of the
keeper 4. When the receiving-instrument is placed on the hook, the pressure of the
spring is overcome, and the lever is depressed to the bottom of the keeper. The
lever 2 is connected with movable devices, which serve to open and close the local
and line circuits comprised in a local-telephone system. These movable devices
consist of two vertically sliding plates or shoes, 8 x and 9x, which are made of
unequal length, as seen in the drawings, and have strips, 10 x, of wood or other non-
conducting material set upon them. The plates or shoes 8 x and 9 x are preferably
made of metal, and they have beveled or inclined flanges 11 r form at the top and
bottom, so as to form a dovetail seat, into which the wooden strip 10x is slipped and
secured by said flanges. Slots 12 x are provided at the top and bottom of the metal
plates 8 and 9, and through these slots project headed pins 13 x, which serve as
guides upon which the plates slide up and down. The rear side of each wooden
strip 10 is cut out, as is seen in section in Fig. 5, so as to receive the heads of the
pins 13 and allow the metal plates or shoes to move on said pins.
The longest wooden strip has two dovetail grooves cut in its front face, and the
shorter strip has only one such groove. The grooves in the wooden strips serve to
receive and hold mercury-cups 15 x, two of which cups are mounted on the long
wooden strip and one cup on the shorter wooden strip. The mercury-cups are made
of glass, earthen-ware, or other suitable material and they each have a central well
or tube, 16 x, as illustrated in Figure 7, somewhat in the form of an ordinary ink-well.
On the back of each cup is formed a dovetail tenon, which is slipped into the dove-

page_text: tail groove in the wooden strip 10 x, in order to hold it firmly in place. Each cup
is partly filled with mercury, and the electrode-wires are made to dip into them as
shown in Fig. 7.
In the arrangement represented in Fig. 3 the longest plate or shoe, with its two
mercury-cups, is located near the hinged side of the door 1 x, and the hooked lever
or receiver-support is connected with said plate or shoe by a link, 18 x, and a secondary
lever, 19 x. This lever is fulcrumed at its end 30 .r, and its other end fits into a gain
or notch in the wooden strip, so that when the switch lever is depressed the secondary
lever will be correspondingly moved by the link 18 x, in order to lower the slide or
shoe 8x and carry the mercury-cups away from the electrodes 20 x and 21 x, as will
readily be understood. Near this end of this secondary lever 19 a is attached the
link 26 a, by which it is connected with the tertiary lever 25 x. This lever 25 x, is
fulcrumed in the middle, has the link 26 x pivotally attached at one end, and has the
other end fitted into a gain or notch in the shorter wooden strip 10 x.
In the arrangement seen in Fig. 4 the intermediate levers are dispensed with and
the position of the shoes or slides reversed—that is, the short shoe is brought near the
hinged side of the door and the long shoe near the side where the hooked lever
projects. The switch-lever is in this instance connected by a long link, 28 x, with
the short shoe, and the long shoe is connected by a short link, 29 x, with the switch-
lever. In order to make the connection of the link 29 x with the long shoe, the
middle portion of its lower end is not turned up, but is left horizontal to the face of
the shoe, so as to form a tongue, 30, to which the link is attached.
C
In the form of my invention illustrated in Figure 3, when the receiving-instrument
is hung upon the hook 3 r, that end of the lever being depressed, and operating
through the link 18 x, draws down the end of the secondary lever 19 x, nearest to the
longer shoe 8, causing the shoe 8 and its accompanying apparatus to move
downward. This breaks connection between the electrodes 20, and 21 r, and the
mercury cups 15 x. At the same time the link 26 x, pulling down one end of the
tertiary lever 25 x, with the other end of this lever pushes up the shorter shoe, so as
to make the electric connection of the electrodes 22 x and the mercury-cups 15 a.
When the receiving instrument is taken off the hook 3 x, the spring 3x, pushing up
that end of the lever 2 x, produces exactly the opposite effect, breaking the connection
of the electrodes 22 x, and making the connection of the electrodes 20 and 21 x
The object of this making and breaking the different connections has been herein-
before fully set forth. In the example of my invention illustrated in Figure 4.
the receiving instrument is hung upon the hook 3 x, that end of the lever 2 x is so.
depressed as to, by drawing down the longer shoe 8 x, break the electric connection
of the electrodes 20, 21, and the mercury-cups 15 г. At the same time the other
end of the lever rising pushes the shorter shoe 9 x upward and makes the electric
connection of the electrodes 22 x and the mercury-cup 15 л. When the receiving
instrument is taken off the hook 3 x the contrary result is produced, and the
connection of the electrodes 20 x, 21 x, and the cups 15 is made and the connection
of the electrodes 22 x and the cup 15 x broken. These electrodes are connected in
ordinary and well-known ways with the proper circuits and the main line.
I
When
Having now described and fully ascertained what my invention is and how
the same is performed, as communicated to me by my foreign correspondent, I do
hereby declare that what I claim as my invention and desire to secure by Letters
Patent, is―
1. In a telephone-switch, the combination of mercury-contact-cups, a movable bar,
and electrodes carried by the latter with the switch-lever and the transmitter, receiver,
and line-circuits, substantially as herein set forth.
2. In a telephone-switch system, the combination of mercury contact-cups, a
movable bar carrying electrodes, and an auxiliary lever provided with an electrode
with the switch-lever and the transmitter, receiver, call, and line-circuits, substantially
as herein set forth.

page_text: 3. In a telephone-switch system, the combination of a mercury-cup and a pivoted or
hinged support with the call-box door, and the switch appliances carried thereby,
substantially as herein set forth.
4. In a telephone-switch system, the combination of a movable shoe or slide and
mercury contact-cups mounted thereon with the switch lever connected with said shoe
or slide and electrodes, from and toward which the mercury-cups are carried by: the
movement of the shoe or slide, substantially as described.
5. In a telephone-switch system, the combination of two slides or shoes, mercury
contact-cups mounted thereon, the switch-lever, connections between said slides or
shoes and the switch-lever, and electrodes arranged in co-operative relation to the
mercury-cups, substantially as described.
6. The combination of the metal plate or shoe having flanged ends, the wooden
strip held between said flanges and having a seat or groove, and the mercury-cup
fitted in the latter, with the switch lever, the fixed electrodes, and guides upon which
the metal plate or shoe can slide, substantially as described.