Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND APPARATUS FOR THE RECOVERY OF BODIES TOWED
FROM MOVING VEHICLES
FIELD OF 1NVENTION
This invention relates to towed bodies and more particularly to a recovery
mechanism for recovering the towed body for reuse.
BACKGROUND OF THE INVENTION
As will be appreciated, aerial towed objects are used for a variety of
purposes,
including decoys, testing, and scientific investigations. In one embodiment
the decoys
are used to draw various types of guided weapons away from an aircraft that
the
weapons are intended to destroy. As will be appreciated, these towed targets
and
decoys contain various types of electronic circuits to create an apparent
target to a
weapon to attract the weapon to the decoy rather than the aircraft. One such
active
electronic device is a amplifier wave tube transponder to which high voltages
must be
applied to power the traveling wave tube. Additionally, other controls for the
traveling
wave tube or other electronics in the towed object are transmitted in one
embodiment
along a fiber-optic transmission line, which is both fragile and frangible.
The typical manner of deployment is such that when the decoy has fitlfilled
its
function, it is simply cut loose. In this case, the fiber optic wires and the
high tension
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line are severed, with the severing taking place after the high voltage has
been removed
and after all usable signals along the fiber optic cable have been
terininated.
The practice of cutting loose decoys after use and using them as an expendable
commodity causes a number of problems. As a result it becomes important to be
able to
recover the towed vehicle itself, mainly because of the cost of the towed
vehicle, as
well as the fact that replacing towed vehicles often is difficult due to the
long lead times
for the manufacture and provision of such decoys.
For instance, typically a towed counter-measure decoy may cost as much as
$50,000 per decoy round. As many as eight decoys per sortie or mission can be
deployed and as such, assuming 400 sorties per month, then the total expense
of
deploying expendable decoys is quite large, making the cost for the protection
of the
aircraft that employs these decoys excessive. Moreover, in a wartime setting
the decoy
cannot be manufactured quickly enough. So bad is the situation that it may be
necessary to scrounge used decoys from the battlefield where they fall.
It will be appreciated that prior to the subject invention, the only type of
retrievable devices from aircraft were the sonobuoys that were dropped froin
helicopters on a line and then winched back up into the helicopter itself.
Another type
of towed device is an air speed head that is used to measure a variety of pat-
ameters
behind an airplane. These types of devices were winched back into a pod on the
aircraft
in a conventional manner.
It will be appreciated that in the above examples of winched-in sonobuoys or
towed instruments, the instruments were never meant to be disposable and were
never
used, for instance, in any kind of airborne counter-measure environment. Thus
they
were not carried in such a manner that they could be rapidly deployed in a
battlefield
scenario.
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Previous embodiments of the above airborne-winch systems are incompatible
with deployment of towed decoys and current volume constraints on tactical
aircraft,
both due to size and due to problems with slowly winching out a drogue or
towed
vehicle of any kind. Note that sonobuoys and pod-mounted countermeasures
typically
were carried in an equipment pod the size of the MK-84 aerial bomb or the
ALQ164-
type electronics counter-measures pod. What will be appreciated is that these
pods are
exceptionally large and preclude, for instance, the carrying of armaments in
the position
where a pod is located. Thus the payload of any attack aircraft is severely
limited when
using such unwieldy winching systems along with associated housings which are
many
times the size of the normal decoy round.
There is therefore a need for a compact launching and retrieval system for
decoy rounds with an improved and miniaturized winching mechanism that would
permit both rapid deployment of the decoy while at the same time being able to
reel in
the decoy and permitting it to dock so that it can be recovered.
By way of further background, the types of decoys involved have included
devices which counter-measure infrared guided and radar guided missiles that
pose the
primary threats to military aircraft engaged in a combat environment. It will
be
appreciated that these missiles use their radar guidance systems to get within
striking
distance of the aircraft, thereby substantially increasing their probability
that the IR
system on the missile will be able to lock onto the target.
Current military aircraft are particularly vulnerable to attack from IlZ-
guided
surface-to-air and air-to-air missiles. Statistical data of aircraft losses in
hostile actions
since 1980 show that almost 90 percent of these losses have been the result of
IR-
guided missile attacks. As a result, the ability to_deploy and then recover
decoys that
can counter==measure the IR guidance systems on these missiles is of great
value to
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protect aircraft during combat situations. As mentioned above, the IR-guided
system
initially utilizes radar guidance and then switches over to IR guidance as
they come into
closer proximity to the target. If one can counter-measure the radar system,
then the IR
portion can never lock onto the particular infrared target. To do this, the
missile is
deflected away by generating a signal that causes the radar guidance systeni
in the
missile to tl-ink that the target is actually elsewhere than it actually is.
In the past, the ALE-50 Towed Decoy system currently in the inventory of the
US Armed Forces includes a decoy round in a canister and a reel payout
mechanism.
When the decoy has served its purpose, it is cut loose and the ALE-50 decoy is
lost.
Moreover, the same scenario is true for the more modern ALE-55, or in fact,
any type of expendable towed vehicle.
In summary, prior art decoys were intended to be sacrificed and the towline
was
typically cut at the aircraft at the end of flight or mission. Thus, these
systems did not
contemplate the winching in or reeling in of the decoy. The reason is because
these
decoys needed to be rapidly deployed. One rapid deployment method included a
spindle that paid out the towline in much the same way as a spinning reel pays
out
fishing Iine. Although spinning reel-like techniques have existed for fishing,
in the area
of rapidly deployed decoys they were not used to winch decoys. Also, the
spindles
themselves were not necessarily driven.
As will be appreciated, there are a number of US patents that in general cover
towed vehicle deployment, such as US Patents 5,836,535; 5,603,470; 5,605,306;
5,570,854; 5,501,411; 5,333,814; 5,094,405; 5,102,063; 5,136,295; 4,808,999;
4,978,086; 5,029,773; 5,020,742; 3,987,746 and 5,014,997. In none of these
patents is
the subject retrievable system shown or taught.
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STJMMARY OF THE INVENTION
In the subject system, a device is deployed that captures the towline and
reels it
in to the can.ister so that as the towline is brought in, the deployed decoy
is reeled in,
and is secured to a cradle or saddle which telescopes out from the canister
during the
retrieval process. The decoy is captured by the cradle due to the tug of the
tow line
around sheaves or other like devices such that the decoy is taken up and is
held to the
cradle from whence it can be removed when the aircrafft returns to base.
The result is that the decoy is not lost or sacrificed but is rather brought
back for
reuse or refurbishment, tlius ssving both time and money when it comes to
redeployment.
As part of the subject invention, the towline is not itself initially winched
but
rather is lassoed, with the lasso being winched in. In one embodiment, the
lasso is
within an annular ridge on a frame through which the towlines pass as they pay
out.
Since the towline is taut between its point of anchor to the canister and the
decoy, the lasso collapses down around the towline and causes a loop to be
formed in
the towline. This loop is then dragged to a motor-driven spindle, which when
activated
causes both the lasso and the looped portion of the towline to wrap around the
spindle.
When a sufficient number of turns of the looped towline are wrapped around the
spindle, the portion of the towline anchored to the canister is cut and the
friction of the
already wrapped towline is sufficient to draw in the decoy until such time
that it is
snugged up to the now-deployed cradle. This means that the decoy can be
rapidly
deployed from a fixed spindle on which the towing line is carried without
having to
have the spindle also function as a winch which would limit the speed of
deployment.
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The result is that a compact deployment and retrieval canister 1/10th the size
of
the aforementioned pods can be utilized so that the decoys need not be
sacrificed.
Moreover, because of the compact size of the deployment canister, the
canisters can be
affixed to the aircraft at points which do not interfere with the placement of
weapons
loads. The result is that decoys can be stored, launched and retrieved without
diminishing the weapons payload of the aircraft.
In summary, recovery of a towed body, in one embodiment in the form of a
decoy which is initially stowed in a receptacle or canister and which is
allowed to pay
out behind an aircra$ on a towing cable wrapped around a spindle, is
acconiplished by
snaring or lassoing a portion of the towing cable and by dragging it to a
further spindle
which is driven so as to cause the lasso and a portion of the towing cable to
wind up
around the driven spindle. When a sufficient amount of the cable is wound
around the
driven spindle, the cable end secured to the canister is severed to allow all
of the rest of
the towing cable to be wound up. In one embodiment, a telescoping saddle or
docking
cradle is provided which extends from the canister to receive the retracted
towed body
so that it may be secured to the moving vehicle from whence it can be
recovered,
refurbished and redeployed.
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In accordance with one aspect of the present invention, there is
provided a system for recovery of a body towed from a moving vehicle utilizing
a
towing cable, comprising: a lasso positioned about said cable and having a
free
end, said cable being under tension during towing; a winch having a driven
spindle, said free end attached to said spindle and adapted to draw in said
lasso
and the cable lassoed thereby; a motor for driving said winch to reel in said
body;
and, a cutter for severing said cable when a predetermined number of terms of
said cable have been winched in over said spindle, whereby said body can be
recovered.
In accordance with another aspect of the present invention, there is
provided a method for retrieving a decoy having a towing cable secured to a
decoy canister, the cable being carried on a spindle in the canister and
pulled out
to permit rapid deployment of the decoy, the decoy being retrieved without
driving
the spindle, comprising the steps of: lassoing a portion of the towing cable
after
deployment of the decoy; reeling in the lasso and the lassoed portion of said
cable
onto a driven spindle; and, severing the cable adjacent to the secured end
thereof
after a predetermined number of wraps of said cable have been wrapped around
the driven spindle.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the subject invention will be better
understood in connection with the Detailed Description and in conjunction with
the
Drawings, of which:
Figure 1A is a diagrammatic representation of a fighter aircraft
showing the deployment of a decoy from a canister which is clearly 1/10t" the
size
of pods previously utilized for winching or electronic countermeasure
equipment
housing;
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Figure 1 B is a diagrammatic illustration of the severing of the towline from
such a pod, thereby resulting in the loss of the decoy;
Figure 2 is a perspective and diagrammatic illustration of a canister showing
the
deployment of a decoy from an upper portion thereof, with a lasso surrounding
the tow
cable and running through an extensible or telescoping saddle or cradle decoy
recovery
unit;
Figure 3 is a diagrammatic illustration of the lasso of Figure 2 in exploded
form,
illustrating the placement of a loop into a retaining slot in frame of Figure
1, also
showing the attachment of the lower end of the loop to a driven spindle;
Figure 4 is a diagrammatic illustration of the canister of Figure 2
illustrating the
telescoping deployment of the saddle or cradle, showing the feeding of the
secured end
of the loop through sheaves or rollers in the extended cradle back to a driven
spindle;
Figures 5A, 5B, 5C and 5D are sequential diagrammatic illustrations of the
snaring of the towed cable, formation of a loop in the towed cable created by
the
drawing of the lasso towards the driven spindle, and the wrapping of the
looped towline
around the driven spindle to a point at which the secured end of the towline
may be
severed; and,
Figure 6 is an isometric view of the capture of the towed decoy and the
telescoping docking cradle once the decoy has been retrieved through the
winding up of
the towed cable on the driven spindle.
,
DETAILED DESCRIPTION
Referring now to Figure lA, an aircraft 10, here a fighter aircraft such as an
F-
1 S, is provided with a canister 12 from which a decoy or drogue 14 is
deployed after
the aircraft, with the decoy being towed via a towline 1.6 as illustrated.
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The actual dimensions of the canister, in one embodiment, are 2-3/4" by 2-3/4"
by 22" in length. As shown in dotted outline 18, typical countermeasure pods,
which
are usually affixed to the underside of the aircraft, are on the order of 12-
18 inches in
diameter and are as long as eight feet in length. It will be appreciated that
such a large
pod precludes the co-location of armament of any kind in that area and in
addition
contributes significantly to wind drag. It will be appreciated that the wind
drag caused
by such electronics countermeasure pods can significantly decrease the range
of such
fighters and is therefore to be avoided.
As shown in Figure 1B, in the prior art, when the decoy 14 has served its
purpose, towline 16 is severed as illustrated at 20, such that the decoy or
drogue is lost.
What is therefore necessary is a deployment and retrieval system which is both
compact and which permits the recapture of the decoy so that it may be reused.
Referring now to Figure 2, canister 12 is illustrated in which towline 16
attached to decoy 14 is shown as having uncoiled from a spindle, not shown,
such that
the stored towline is initially coiled as illustrated at 22, with its proximal
end 24
secured to the canister. When the decoy is deployed, there is significant
tension on the
part of tow cable 16, with the only point of attachment to the canister and
thus the
aircraft being at anchor 26 within the canister.
As will be seen, a telescoping recovery cradle or saddle 301ies underneath an
upper compartment 32 in which the decoy is originally stored. The cradle
carries a
pulley 31 about which cable 16 goes during deployment. It will be appreciated
that
compartment 32 is in essence a sub-assembly of the canister, which can be
mounted on
the retrieval portion 34 of canister 12 and can be any of a variety of
deployment
canisters, such that the subject retrieval system is not limited to any one
type of
deployment canister, but rather can accommodate pre-packed decoy rounds from a
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number of different sources. Note that there can be single or multiple cables
between
the canister and the decoy.
The problem then becomes that rather than cutting the towlines, how is it
possible to recover a decoy that may have as many as three or four lines
attaching it to
the canister.
In order to accomplish the snaring of one or more lines that function as
towlines
or signal lines and referring now to Figure 2, a loop or lasso 40 is
positioned at a free
edge of a frame 42 which is at the distal end 44 of the canister subassembly,
such that
the lines pass through the orifice defined by the loop. As will be seen in
Figure 3, there
is a joined portion 46 of the loop, with a line 47 from this joint running
back through
the telescoping cradle as will be discussed.
Referring to Figure 3, loop 40 is illustrated as being mountable in a loop-
retaining slot 46 in frame 42, which may be held in the slot by wax or
silicone
adhesive.
Line 47 from the joined portion 46 of loop 40 is shown schematically to go
around a pulley 50 and then around a pulley 52 where it is secured at 54 to =a
motor-
driven spindle 56, which is driven by a motor 70 in the direction of arrow 58
during the
retrieval process.
Referring now to Figure 4, with the telescoping cradle shown in the retrieval
position as illustrated, the loop or lasso 40 is drawn by line 47 towards a
pulley 60 up
over a pulley 62 and then down through a pulley 64 from whence it is routed,
as
illustrated by the dotted portion of line 47 to spindle 56 which is driven by
motor 70.
Referring to Figure 5A, from a schematic point of view, loop 40 is shown to
engage line 16 witli the secured part of the loop having line 47 which goes
over and
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around a number of pulleys 72 and 74, where it is wrapped as illustrated at 76
on
rotating spindle 56.
Referring to Figure 5B, a loop 80 is formed by the dragging of the loop 40 in
a
downward direction, with line 16 going between pulleys 82 and 84. The dragging
of
this line, which will be appreciated as being in high tension, results in the
dragging of
loop 80 around spindle 56 as illustrated in Figure 5C.
When a sufficient amount of looped line 80 is coiled about spindle 56 as
detected at 85, then line 16 is severed as illustrated at 86 via a wire
cutting actuator 88
in response to an output from detector 85, and the retrieval of line 16
continues due to
the number of wraps on the spindle being sufficient to prevent loss of the
decoy.
Referring now to Figure 6, what is shown is the retrieval of decoy 14 into the
telescoping docking saddle or cradle 30, which is shown in its deployed
position,
having moved as illustrated by arrow 90 aft of canister 12. This is
accomplished
through the use of an actuator 114 under the control of a control unit 110.
As can be seen, saddle or cradle 30 is provided with tangs 92 and 94, which
coact with the top surface of the decoy and serve as a saddle for keeping the
decoy in
place in the saddle when line 16 is drawn taut, with line 16 going between
rollers 60
and 62.
Also shown is a bumper or stopping mechanism 96 which prevents the decoy
from moving forwardly, with the nose 98 of the decoy coacting with this bumper
to
prevent movement of the decoy when it is reeled into its stored position.
It will be appreciated that the translatable telescoping docking saddle is
deployed only after the decoy is beyond a certain prescribed distance from the
canister
so as not to interfere with the paying out of the towing cable.
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Key to the reeling in of the decoy so that a maximum amount of cable can be
stored in a compact way on a spindle and to prevent untoward fouling of the
cable
around the spindle during the retrieval process, is a level-winding spindle
system 100 in
which cable being retrieved or wound around the spindle is optimally wrapped
around
the spindle due to the operation of a driven guided carriage mechanism that
guides the
cable onto the spindle due to helical driven grooves on a rotatable shaft that
translates
the carriage guidance mechanism back and forth over the driven spindle in
timed
relationship thereto.
The utilization of a level-winding spindle in the subject invention permits
recovery of larger amounts of cable than heretofore possible because of the
efficiency
of the level winding system. Not only is the efficiency important but also the
relative
freedom from fouling and snapping in such a system permits more secure
retrieval of
the decoy itself.
Having now described a few embodiments of the invention, and some
modifications and variations thereto, it should be apparent to those skilled
in the art that
the foregoing is merely illustrative and not limiting, having been presented
by the way
of example only. Numerous modifications and other embodiments are within the
scope
of one of ordinary skill in the art and are contemplated as falling within the
scope of the
invention as limited only by the appended claims and equivalents thereto.
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