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Патент USA US2404179

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E. B. KING
£944,179
ELECTRICAL SWITCHING DEVICE
Filed June 28,v 1943
53
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Attorney
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Patented July 16, 1946
2,404,179
UNITED STATES PATENT OFFICE
2,404,179
ELECTRICAL SWITCHING DEVICE
Edward Bolton King, Haslemere, England
Application June 28, 1943, Serial No. 492,616
In Great Britain April 17, 1942
4 Claims. (Cl. 200-33)
1
2
This invention relates to electrical switching
bined with a relay for initiating detonation of the
arrangements and has as its main object the
production of a, switching arrangement, for ex
charge of a rocket or other non-rotated pro
jectile, in which case the switches are so con
structed and supported as to withstand the
ample, for controlling a relay device, which is
responsive to changes in velocity of apparatus 5 stresses due to the high acceleration of the pro
jectile. Another application of such arrangement
carrying the arrangement.
is in combination with a relay for controlling ele
The improved switching arrangement, accord
vators and/or steering mechanism of an aircraft,
ing to the invention, comprises an acceleration
the relay being energised to e?ect a control op
switch arranged to operate its contacts due to the
inertia of a moving part during acceleration in 10 eration when the aircraft decelerates following
a high speed evolution; for example, a steep dive.
a predetermined direction and a deceleration
Such an arrangement can also be used for con“
switch arranged to operate its contacts due to the
trolling the detonation of a projectile or bomb
inertia of a moving part during deceleration, one
when it reaches a predetermined depth below the
of the switches being irreversible, that is. remain
ing closed (or open) after operation, so that both 15 surface of the water, the acceleration switch be
ing operated during an initial acceleration period
switches are in their operated positions after an
whilst the deceleration switch operates when the
acceleration period followed by a deceleration pe
projectile slows up immediately following its im
mersion in the water.
ried, or vice versa.
Preferably the irreversible switch consists of a
switch of the type employing a conducting liq
uid, such as mercury, and including a. capillary
tube substantially parallel to the direction of
motion along which the liquid is forced to close
contacts at the remote end of the tube when
the rate of change of velocity (the acceleration
or the deceleration) exceeds a predetermined
value for a predetermined time. Conveniently
A construction of the switch arrangement ac
cording to the invention which is particularly
suitable for controlling the arming of a prox
imity fuze for rockets or other non-rotating pro
jectiles will now be described by way of example
25 with reference to the accompanying drawing in
20
which
‘
Fig.v 1 shows a preferred form of capillary
one or more intermediate “traps” or bulbs are
switch;
provided between the ends of the capillary tube
Fig. 2 shows a preferred form of non-capillary
switch; and
Fig, 3 shows the method of assembling the
switches.
to prevent closing of the switch due to accidental 30
shocks or to vibration.
The switch which is not irreversible may com
prise a tubular non-capillary switch employing a
conducting liquid, such as mercury, and arranged
_
The function of a switching arrangement, ac“
cording to the invention, in a proximity fuze is
substantially parallel to the direction of motion 35 mainly as a two-stage arming device to ensure
with the contacts to be closed at the appropriate
that the projectile is safe to handle before it
end of the tube.
is ?red, that electrical apparatus, such as ther
The capillary switch may be so arranged and
mionic valves, forming part of the fuze is pre
pared for operation during the preliminary part
dimensioned that it closes when the force is a
large multiple of the force required to close the 40 of the ?ight of the proectile without the fuze be
non-capillary switch, or the switches may be so
ing completely armed whilst it is close to and
dimensioned and the conducting liquids so chosen
therefore sensitive to the ground, and, ?nally,
that the forces which cause closing of the re
that complete arming is e?ected when the pro
spective switches may be of substantially the same
jectile is at a su?icient distance from the ground
45 to be substantially immune from ground eiiects.
order of magnitude.
'
In a convenient practical arrangement a capil
lary acceleration switch and a non-capillary de
celeration switch have their contacts connected
In such fuzes, detonation is controlled by a re~
lay which preferably comprises a gas-?lled ionic
valve, such, for example, as a valve sold under
in series in a circuit of a relay, for example, in
the registered trade-mark “Thyratrcn,” having
the anode circuit of a gas-?lled triode relay, 50 a control grid by means of which the relay is trig~
whereby the circuit is prepared by closing of the
gered. The triggering impulse may be supplied,
preferably through an ampli?er, from a photo
pleted by closing of the non-capillary switch
electric cell arrangement responsive to changes
when deceleration begins.
.
in illumination caused by the target or by a
Such a switching arrangement may be com 55 radio receiver responsive to radio-frequency os
capillary switch during acceleration and com
2,404,179
3
4
tube contains su?icient mercury B3 to produce
adequate low-resistance contact between the two
from the ground.
wires when the tube is inverted, but the'amount
The switching arrangement according to the
of mercury should not be such as to prevent free
invention is so arranged that the acceleration
switch A, which is the irreversible switch, when UK movement thereof in the wider portion of the
cillations re?ected from the target or transmitted
it operates completes the ?lament and anode cir
cuits of any thermionic valves employed in the
ampli?er and other apparatus and also closes a
tube. A small quantity of a. suitable powder such
as aluminium oxide, may be added to the mer
cury to facilitate free movement thereof. The
tube may be exhausted or may be ?lled with air
point in the anode circuit of the gas-?lled relay.
or other gas at a suitable pressure.
The circuits are thus prepared for operation dur
The dimensions of the acceleration and decel
ing the initial acceleration of the projectile.
eration switches described above are such that
Complete arming of the fuze during this period
the acceleration switch will be operated by an
is prevented by the open contacts of the decel
acceleration of the order of 40 times that of
eration switch B, these contacts being included
in the anode circuit of the gas-?lled relay. Thus, 15 gravity averaged over a period of from 0.4 to 1
second, whilst the deceleration switch is sensitive
when the projectile begins to deceler-ate, that is,
to a deceleration force of approximately 0.3 times
when, in the case of a rocket, the propelling
that of gravity for a very short period.
charge is fully burnt, the deceleration switch B
The several switches are mounted with their
closes and the fuze is then fully armed so that
it responds to the re?ected radiations from the 20 axes parallel to one another and to the axis of
target as soon as the projectile approaches sufq
the projectile, as shown in Fig. 3. In order that
?ciently close thereto.
they will withstand the high stresses due to the
In such an arrangement a separate accelera
rapid acceleration of the projectile, they are as
tion switch is provided for each of the independ
sembled and bound together in a suitable plastic
or semi-plastic material such as para?in-wax.
ent circuits to be closed, each switch convenient1y consisting of a glass capillary tube having an
Alternatively, they can be mounted in grooves
internal bore A! (Fig. 1) of between 0.12 and 0.16
in a former of ebonite or other synthetic insulating
millimetre in diameter. The tube, which is about
material, and enclosed in a varnished paper tube,
5 centimetres overall length, has at its lower end,
the complete assembly being, if desired, impreg
that is the end nearest to the rear end of the 30 nated with a suitable bonding material.
projectile, a small bulb A2 of between 3 and 4
It is to be understood that the speci?c construc~
millimetres in diameter through the wall of which
tion of switching arrangement described above is
are sealed two metal Wires A3 of a suitable al
by way of example only and that the dimensions
loy to form a vacuum-tight seal with the glass,
and the mounting of the individual switch ele
the inner ends of these wires, which project into 35 ments can be varied as desired to suit the use of
the bulb, being spaced apart from one another.
the switching arrangement. It will also be ap
At the upper end of the tube there is another
preciated that whilst various applications of‘ an
bulb A4 containing a small amount of mercury.
arrangement according to the invention have been
The tube is evacuated to a low pressure and sealed
speci?cally referred to, such an arrangement can
40
at its upper end. The amount of mercury and
be used in any apparatus or vehicle where it is
the bore of the capillary are such that, due to
desired to complete (or to open) an electric cir~
surface tension, the mercury will not enter the
cuit as a result of successive acceleration-decal“
capillary as a result of accidental shocks or nor
eration periods or vice versa. When the circuit
mal vibration, but, when the switch is subjected 45 is to be opened the capillary switch or switches
to high acceleration, for example an acceleration
will, of course, be arranged so that normally the
of the order of 40 g., the thrust due to the inertia
conducting liquid closes the contacts but moves
of the mercury is su?‘icient to force mercury along
under the in?uence of the appropriate accelera
the bore of the tube. If such acceleration is
tion or deceleration to an empty bulb at the re
maintained for a su?icient time, which depends 50 mote end of the capillary.
on the length of the tube, the mercury will ?ll
I claim as my invention:
the bulb at the lower end of the tube and thus
1. In a body subject to changes of velocity, an
complete a low resistance contact between the
electrical switching arrangement for controllingr
wires projecting into the bulb. The switch thus
electrical circuits carried by the body comprising
closed will remain closed unless it is subjected 55 a ?rst switch adapted to operate in response to a
to a correspondingly high acceleration in the op
change in velocity of one sign and thereafter to
posite direction.
remain locked in the operative position and a
In order to ensure that vibration will not cause
second switch adapted to operate in response to
mercury to reach the lower bulb, an interme
a change in velocity of the opposite sign said first
diate trap or bulb A5 may be formed in the capil
60 switch comprising a capillary tube for each pair
lary about midway between the ends.
of contacts to be operated, a bulb at each end of
If mercury should penetrate to such trap due
said capillary, a pair of said cont-acts protruding
to vibration, it is likely to return to the upper
through the wall into one bulb and a conducting
bulb as a result of further vibration.
in one bulb, and said second switch com
A preferred construction of deceleration switch 65 ?uid
prises a non-capillary tube for each pair of con
is shown in Fig. 2 and comprises a glass tube hav
tacts to be operated, a pair of said contacts pro
ing a length of approximately 4 centimetres and
truding through the wall into one end thereof and
an internal diameter of between 4 and 5 milli
a conducting fluid at one end thereof.
‘
metres. In this case, contact wires Bl , B2 project
2. In a body subject to changes of velocity an
into the upper end of the tube which is prefer
ably of slightly reduced internal diameter, the 70 electrical switching arrangement for closing in
inner ends of the contact wires preferably project—
ing beyond the point at which the diameter of
the tube is reduced, for example, from the up
per end of the tube to a. distance of between a.
half and a third of the length of the tube. The
two stages electrical circuits carried by the body
comprising for each pair of contacts to be closed
in the ?rst stage a capillary tube, a bulb at one
end of said tube, a pair of said contacts in the
bulb and a mercury reservoir at the other end of
5
2,404,179
said tube, said mercury ?owing through said
tube into the bulb in response to a change of
velocity of one sign to bridge said pair of con
tacts and to complete the ?rst stage of closure of
electrical switching arrangement for controlling
electrical circuits carried by the body comprising.
a ?rst switch adapted to operate in response to
a change of velocity of one sign and thereafter to
said circuits, and for each pair of contacts to be 5 remain locked in the operative position, and a
closed in said second stage a non-capillary tube,
second switch adapted to operate in response to
a pair of said contacts protruding into one end
a change in velocity of the opposite sign, said
of the bore of the tube, a globule of mercury
?rst switch including a pair of contacts to be
adapted to move freely in the bore in response
operated, a mass of material arranged to move
to a change of velocity of the opposite sign to 10 freely in one direction from one position to an
bridge the contacts and to complete the second
other and to close said contacts in one of said
stage of closure of said circuits.
positions and means for preventing the return of
3. An electrical switching arrangement ac
the mass in the opposite direction, and said sec
cording to claim 2 wherein each capillary tube
iS provided with an intermediate bulb substan
tially midway between its ends, said intermediate
bulb acting as a trap to prevent mercury reaching
the contacts as a result of vibration.
4. In a body subject to changes of velocity, an
ond switch includes non-capillary tube, a pair of
15 contacts to be operated protruding through the
Wall into one end thereof, and a conducting ?uid
at one end thereof.
-
EDWARD BOLTON IHNG.
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