The Holly chieftain., 1923-06-14

Mechanical Relay Adaptable to
BY John F. sront.
Some interesting results have been
obtained with relay built in similar
way to the one described and sketched
here The mechanical working prin-
riple Of the apparatus Is not new one,
yet is uniquely applied in the recording
of received radio time signals by isoIat-
ing them In a local circuit in which is
Included recorder. Curiously enough
the instrument is applicable to record
Ing of continuous wave signals, more
10 than to those Of decaying trains.
In detail we may examine what takes
place when a straight steel wire has
either or both Of Its ends thrust to-
ward each other. A very slight move
ment Of the ends toward each other is
followed by the wire bowing outwardly
In the center and forming an arc. The
closer the wire is to its 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 a
direction along the original normal
axis of the wire, for a given move
ment Of the ends toward each other.
The slight movement of the ends to-
ward each other, in fact, is magnified
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-
tion grows less. II curve were
!. drawn, 1t would show a steep portion
at the beginning and gradually round
Ing of 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
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
cluded 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 a micrometer ar.
rangement which requires n large
movement Of the adjusting screw for u
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
n change In the position of the center
Of the wire and II the micrometer ap-
paratus is adjusted correctly local
circuit will be opened and closed at
each movement of the diaphragm. Es-
pecially where continuous waves are
being dealt with, this type Of relay
Is most eficient, and 1t 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 permanent
magnet placed Immediately below the
wire 30 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 Ia COM
municated to 1t, through the action of
the rectIfed trains Of continuous
waves.
The whole apparatus is in fact an
amplif1er and relay at the same time,
although 1t has been made up for re.
laying only. The diaphragm movement
Is amplif1ed In the movement Of the
center Of the wire, which movement Is
the agency In closing and opening a
local circuit. Experiments were made
which reversed the usual order Of
things and arranged for the breaking
Of local circuit which would operate
recorder instead of the usual type
which is made to close local circuit.
Batteries.
Primary batteries were connected in
series with the recorder ana one end