The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1923-06-15
Mechanical Relay Adaptable to
BY John r, Bront.

Some interesting results have been
obtained with relay built in similar
way to the one described and sketched
here. The mechanical working prin-
ciple Of the apparatus is not new one,
yet is uniquely applied in the recording
of received radio time signals by isolat-
Ing them in local circuit in which Is
included recorder Curiously enough
the instrument is applicable to record
ing OF conti.- uOus wave signals, more
so than to those of decaying trains.
In detail we may examine what takes
place when a straight steel wire has
either or both of it's ends thrust to-
ward each other. A very slight move
ment Of the ends toward each other Is
followed by the wire bowling outwardly
In the center and forming an arc. The
closer the wire is to it's normal shape
the greater will be the movement Of
the center Of the wire outwardly from
Its normal position, when pressure is
applied at either or both ends in
direction along the original normal
axis Of the wire, for a given move
The slight movement of the ends to-
ward each other, in fact, is magnif1ed
In the resultant movement or bending
out of the center. AS the ends are
moved nearer each other, the resultant
outward movement of the center por-
ton grows less. If a curve were
drawn, it would show a steep portion
at the beginning and gradually round
Ing off toward the point represented
where the ends Of the wire are sup
posed to be parallel with each other
in the bending process. That is when
the wire is bent double.
Construction of Relay.
In the relay sketched here the steel
wire is fastened to the diaphragm of
a large-sized receiving phone. At the
center where the greatest movement
takes place for given thrust on either
end, is placed contact which is in
Guided in local circuit, as is portion
Of the steel wire itself. The opposite
end of the wire is securely held rigid
The contact below the center of the
wire is adjusted by micrometer ar
rangement which requires a large
movement Of the adjusting screw for
slight change in the height of the con-
tact, which is made Of spring brass
and securely fastened at one end, while
the lower end is drilled to pass the
screw of the adjusting arrangement
and fits against the adjusting nut.
Operation.
In operation, the attraction of the
diaphragm at each wave train makes
a change in the position of the center
of the wire and if the micrometer ap-
paratus is adjusted correctly a local
circuit will be opened and closed at
each movement of the diaphragm. Els
pecially where continuous waves are
being dealt with, this type Of relay
is most efficient, and it is necessary
only to rectify the received trains,
without going through the operation
of heterodyning. Each arriving train
will cause attraction and release the
diaphragm, which movement is COM
municated to the steel wire.
The wire is not maintained at its
exactly straight horizontal position.
but slightly bowed down in the center
to facilitate the action Of a permanent
magnet placed Immediately below the
wire so as to insure the movement of
the center of the wire downward and
not to one side or upward when the
movement of the diaphragm is COM
municated to it, through the action of
the rectified trains of continuous
waves.
The. whole apparatus is in fact an
amplifier and relay at the same time,
although it has been made up for re-
laying only. The diaphragm movement
is amplified in the movement of the
center of the wire, which movement is
the agency in closing and opening
local circuit. Experiments were made
which reversed the usual order of
things and arranged for the breaking
of local circuit which would operate
a recorder instead of the usual tyne
which is made to close local circuit.
Batteries.
Primary batteries were connected in
series with the recorder and one end
Of the steel wire, the circuit leading
through the relay contacts when the
circuit is closed by the movement of
the wire.
In the reception of decaying trains
of waves there is a movement of the
phone diaphragm for every rectified
train and if this type Of relay were
employed in the isolation of such sig