Year: 1888

page_text: I, CHARLES LANGDON DAVIES of 110 Cannon Street in the City of London,
Electrician, do hereby declare the nature of this invention to be as follows:-
According to this invention the ordinary lever or finger key or other instrument used
for the transmission of electrical signals or currents makes various commutations in
addition to and without affecting the ordinary working. I do this by means of a
movable pin contained within the anvil or other contact, the pin going through
the anvil and being provided with a head having a shoulder to come against
the anvil. When this pin is pressed by the key its end first moves the lever
of a contact maker and makes the desired commutation or commutations and
afterwards the shoulder comes against the anvil and either acts as a stop in which
case the head is usually of insulating material, or it makes contact for the ordinary
working of the instrument and in this case the head of conducting material. I
prefer to carry the pin by means of a flexible washer or washers fixed upon the inside
of the anvil block, and I usually make it wholly or partly of insulating material.
The apparatus is useful in all cases in which a circuit or circuits are required to be
opened, closed or varied before, after or simultaneously with the transmission of the
signals or other action produced by working the key, as, for example, when it is
required to cut out from the circuit the receiving instrument at the station which is
about to transmit a telegraph message. The pin may perform the desired operations
in a variety of ways it may press one or more contact makers, it may break some
circuits and make others or it may itself form a contact maker or it may turn a
commutator ratchet wheel so as to reverse the current and so forth; it may be applied
to one or more contacts of the same key, and it is equally available for use in keys
worked by hand and in those parts of machines which perform the office of the key
although worked by mechanical means.
Dated this 2nd day of March 1888

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Contact Makers and Commutators.
I, CHARLES LANGDON DAVIES late of 110 Cannon Street in the City of London
now of Mowbray House Victoria Embankment London Electrician 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 :-
According to this invention-the-ordinary lever or finger key or other instrument
used for the transmission of electrical signals or currents makes various-commutations
in addition to and without affecting the ordinary working. I do this by means of a
movable pin contained within the anvil or other contact, the pin going through the
anvil and being provided with a head having a shoulder to come against the anvil.
When this pin is pressed by the key its end first moves the lever of a contact maker
and makes the desired commutation or commutations and afterwards the shoulder comes
against the anvil and either acts as a stop in which case the head is usually of
insulating material or it makes contact for the ordinary working of the instrument and
in this case the head is of conducting material. I prefer to carry the pin by means
of a flexible washer or washers fixed upon the inside of the anvil block, and I usually
make it wholly or partly of insulating material.
The apparatus is useful in all cases in which a circuit or circuits are required to be
opened closed or varied before, after or simultaneously with the transmission of the
signals or other action produced by working the key, as for example when it is
required to cut out from the circuit the receiving instrument at the station which is
about to transmit a telegraph message. The pin may perform the desired operations
in a variety of ways it may press one or more contact makers it may break some
circuits and make others or it may itself form a contact maker or it may turn a
commutator ratchet wheel so as to reverse the current and so forth; it may be applied
to one or more contacts of the same key and it is equally available for use in keys
worked by hand and in those parts of machines which perform the office of the key
although worked by mechanical means.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side view partly in section of a lever finger key to which my
invention is applied.
Figure 2 shows another form.

page_text: In Figure 1 a is the key lever moveable about the fulcrum a'. b is a blade spring
which presses upwards the fore end of the lever. c is the anvil, d is a vulcanite
pin passing through the anvil c; it has a metallic head d¹ which when the key is
depressed makes contact with the anvil and closes the ordinary working circuit of
which the wires indicated at ee form a part. f is a disc of vulcanised india rubber
holding the pin d in place but allowing sufficient freedom of movement. g and h are
two insulated metal blocks and i is a spring metal blade attached by one end to the
block 9 whilst the block carries an adjustable contact point h¹. k k are wires
connected with the blocks g and h and forming part of a second circuit closed by the
key. This arrangement allows of the same finger key being used to transmit into
two circuits in which instruments of different class may be in use.
In figure 2 the key is shown arranged to open one contact when it closes the other
or main contact. The contact point is in this case above the spring blade i and as
the drawing shows it may be adjustable by means of a screw. The screw is insulated
from the anvil.
In figure 3 a like arrangement is shown in connection with the back contact of the
key. In this case the screw / carried by the key lever at its rear end operates upon
the vulcanite pin d and by its means opens a contact.. m represents a receiving
instrument which is shunted by the spring blade i when this is on its contact; that is
to say when the key lever is depressed but at other times the receiving instrument
is in the line circuit. With this arrangement outgoing signals do not affect the
home instrument.
The movable pin d in place of being in the anvil may be carried by the key lever.
Figure 4 shows this arrangement. The key lever also carries the spring blade m and
the contact point n. o, o, are wires connected with these. When the key is at rest
on its back stop the pin presses against the blade m and the circuit of which the
wires o form a part is open but immediately the key is depressed the blade m
comes against n and closes the circuit.
A like arrangement may be made at the fore end of the key lever and then at
the same time that one circuit is closed another will be opened as is the case in
Figure 2.
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
as my improvements in electric contact makers or commutators is :-
1. The combination with the key of a movable pin operated thereby so that in
the ordinary working of the key, opening and closing principal contacts, other
contacts are simultaneously controlled substantially as described.
2. Electric contact makers and commutators substantially as described.
Dated this 1st day of December 1888