Note: Descriptions are shown in the official language in which they were submitted.
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6292-~3
This invention relates to aircraft emergency radio
beacons generally known as crash position indicators (CPI's) which
are intended to transmit distress signals only upon crashing of
the aircraft.
Such CPI's which are designed to deploy from the body of
an aircraft while it is crashing and begin transmitting automatic-
ally more or less simultaneously with the deployment, have hereto-
fore contained activation systems electrically biased-on to trans-
mit downed aircraft distress signals over the International Guard
Frequency (IGF) for the purpose of location and rescue.
Auxiliary batteries generally called shut-off batteries
mounted in the airframe have heretofore been required to counter-
balance the electrical biasing-on of transmitters in CPI's and
hold the transmitter shut off until, in the event of a crash, an
ejector mechanism known as an airEoil release unit, (ARU~, ejects`
the CPI from the airframe thereby breaking the connection to the
shut-off battery and allowing the transmitter to operate.
Auxiliary batteries generally called ground shut-off
batteries supplied as ground support equipment have heretofore
been required to counterbalance the electrical on-biasing of the
CPI transmitter when the CPI was being installed, removed, or
serviced. An alternative to ground shut-off batteries has been to
provide a manual shut-off switch in the CPI.
CPI's used heretofore have been reliable in activation
of the beacon but have shown poor reliability in holding the
beacon in a deactivated position. Human error in attaching the
ground shut-off battery during removal, servicing, a`nd installa-
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tion of the CPI, negligence in turning ofE the manual shut-off
switch, as well as drainage o~ the ground shut-off battery can
cause the CPI to transmit. Drainage of the airframe mounted shut-
off battery due to exceeding of battery recharging intervals,
battery exhaustion, electrical connection failure, failure in
charging systems, or failure of the manual shut-off switch can
cause the CPI to transmit.
The transmission of distress signals over the IGF other
than for short test transmissions is illeyal except in an emer-
gency situation and also causes battery drainage.
It is an object of this invention to provide a CPI thatis as reliable as existing systems in its activation but also very
reliable in holding the beacon in a de-activated mode during
flight and ground servicing.
It is a further object of this invention to provide a
CPI that does not require a ground shut-off battery or manual
switch to hold it in the off position, greatly reducing the factor
of human error in its installation and maintenance.
It is a still further object of this invention to pro-
vide a CPI that does not require an auxiliary battery mounted inthe airframe, thereby reducing the complexity and probability of
malfunction of the system and also resulting in a saving of weight
and space in the airframe~
The present invention provides, in accordance with a
first broad aspect, an emergency transmitter device comprising a
radio transmitter, a battery, and a normally open switch means
electrically connected between the battery and the transmitter,
the device having mounting means for releasably attaching the
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device to an aircraft and co-acting with ejector means on the
aircraft such that that operation of the ejector means causes
release of the device from the aircraft, the switch means being
positioned such that, when the device is attached to the aircraft
and the ejector means operates, the ejector means ac-tivates the
switching means es~ablishing permanent electrical connection
thereby energizing the transmitter from the battery.
According to another broad aspect, the present invention
provides an emergency transmitter device comprising a radio trans-
mitter, a battery, and a deformable normally open switching means
connected electrically between the battery and the transmit~er,
the device having mounting means for releasably attaching the
device to an aircraft, and co-acting with ejector means on the
aircraft such that operation of the ejector means causes release
of the device from the aircraft, the switch means being positioned
such that, when the device is attached to the aircraft and the
ejector means operates, the ejector means permanen~ly deforms the
switch means into a closed position thereb~ energizing the trans-
mitter from the battery.
The foregoing and other features of the invention are
illustrated in the accompanying drawings in which:
Figure 1 is an isometric view of a typical deployable
CPI during release from the airframe;
Figure 2 is a cross-sectional view to an enlarged scale
of the CPI of Figure 1 during release from the airframe;
Figure 3 is a cross-sec-tional view oE an embodiment of
the ARU before release;
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Fig~re 4 is a view similar to Figure 3 but showing the
ARU during releas~;
Figure 5 i5 a cross-sectional view of an installed
deployment sensor switch before release;
Figure 6 is a cross-sectional view of an installed
deployment sensor switch during release;
Fiyure 7 is an isometric cut-away view of an uninstalled
deployment switch.
Referring to Figure 1, a typical mounting arrangement
during release is disclosed. The CPI 1 is positioned in a cut-out
or indentation in the exterior skin 2 of an aircraft in such a way
that the top surface 5 of the CPI 1 more or less conforms to the
aerodynamic shape of the exterior skin 2 of the aircraft. During
release, a cylinder and pressure housing assembly 3 of an ARU
disengages from a retainer assembly 4 of the CPI, the ARU being
positioned near the leading edge of the CPI 1 in relation to the
airstream, allowing the airstream to lift the CPI away from the
airframe.
Referring to Figure 2, an embodiment of a CPI 1 in which
is contained a transmitter 7, a transmitter battery 8, and a con-
nector 9 electrically connecting the transmitter and battery
through a deployment sensor switch 10 which is normally open, thus
preventing the transmitter from being energized, is shown. The
ARU assembly 11 is shown in released position with the retainer
assembly 4 disengaged ~rom the cylinder and pressure housing
assembly 3. The CPI 1 before release is held in position at the
trailing edge of ~he CPI by a hook 14 or like means releasably
engaged in a bracket 6 or similar fitting on the airframe and by
-- 4 --
the ARU 11 engaging retainer assembly 4 so that the top of the
CPI more or less conforms to the aerodynamic shape of the aircraft
outer skin 2. For illustrative purposes, the deployment se~sor
switch 10 is shown in non-deformed condition.
Referring to Figure 3, a cross sectional view of an
embodiment of an AR~ before release is shown in more detail. The
retainer assembly 4 is attached fixedly to the leading edge of
CPI 1 by bolts 22 or like means, while the cylinder and pressure
housing assembly 3 is similarly attached by bolts 22 or like means
to a section of the airframe 21 or some stanchion or bracket
fixedly attached thereto. The cylinder 13 is fixedly attached to
the pressure housing 23, and fitted with a pressure cartridge 24.
A piston 27, comprising a lower portion 2B, a portion of reduced
diameter 16 and a crown 17 is co-axially disposed within the
cylinder 13. The retainer assembly 4, retained onto the ARU by
one or more retaining balls 15 slidably inserted in one or more
ball races lB, is fitted with the deployment sensor switch 10
transversely disposed through a diameter within the retaining
assembly 4. Before release, the retaining assembly 4 is held
together with the cylinder 13 by means of the retaining balls 15
abutting against a cam 19 which is circumferentially shaped around
the inner portion of retainer assembly 4 and abutting also against
the crown 17 of piston 27.
Referring to Figures 3 and 4, the pressure cartridge 24
is electrically connected by cable 25 to an inertia or contact
switch (not shown) of several varieties currently in the art which
are suitable. In the event oE a crash, an electrical signal fires
the pressure cartridge 24, which pressurizes a plenum chamber 40
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below the lower portion of piston 28 by means of a duct 26 within
pressure housing 23, driving the piston 27 upward within cylinder
13.
Referring to ~igure 4, the initial upward movement of
piston 27 allows the portion of reduced diameter 16 of the piston
27 to be disposed against ball race 18, the further upward move-
ment of the piston 27 causing the crown 17 permanently to deform
deployment sensor switch 10. The further upward movement of the
piston 27 urges upward against the retaining assembly 4, causing
the cam 19 to displace the retaining balls 15 inwardly in relation
to the cylinder 13, the balls sliding into the portion of reduced
diameter 16 of piston 27, allowing the retaining assembly 4 to
disengage from the cylinder 13. The further upward movement of
the piston urges the leading edge of the CPI to be inserted into
the position indicated in Figures 1 and 2.
Referring generally to Figure 4, and specifically to
Figures 5, 6 and 7, the deployment sensor switch is comprised of
two metallic elements preferably of copper, namely an outer con-
ductive tube 36 and a central conductor 35 co-axially disposed
2~ within the outer conductive tube 36, electrically insulated from
each other by insulating end plugs 37. The deployment sensor
switch 10 is encased in a sleeve 39 of aluminum coaxially disposed
along the exterior of outer conductive tube 36 which serves to
protec~ the deployment sensor switch 10 from mechanical damage,
and is electrically isolated ~rom sensor switch 10 by insulating
shield 42. Central conductor 35 and outer conductive tube 36 are
connected by wires 43 and 44 respectively to the circuit between
the transmitter 7 and transmitter battery 8. Wires 43 and 44 are
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illustrated separately in Figures 5, 6 and 7 for purposes of
clarity. Practically, they may form separate elements of a
shielded cable. Plugs 37, together with a boot 41 of Elexible
insulating material, preferably p]astic, which surrounds the end
of switch 10 from which wires 43 and 4~ extend, serve to prevent
the ingress of moisture. The upward movement of the piston 27
from the Figure 5 to the Figure 6 position causes the crown 17 to
deform the deployment sensor switch 10 so that outer conductive
tube 36 and central conductor 35 are permanently in contact with
each other, as shown in Figure 6. The deformation shown in Figure
6 is an idealized illustration of the deformation of the deploy-
ment sensor switch 10, the practical deformation may be charac-
terized by a crushing or crimping deEormation which will cause
flattening of the outer conductive tube 36.
The deployment sensor switch 10 need not necessarily be
tubular as described, but may assume other forms, for example, the
form of a snap-dome which provides momentary electrical contact
which can be used with an electrical latching device to provide
permanent switch-on.
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