US3834312A

US3834312A - Parachute-borne flare assemblage

Info

Publication number: US3834312A
Application number: US00355057A
Authority: US
Inventors: B Simmons
Original assignee: Bofors AB
Current assignee: Saab Bofors AB
Priority date: 1973-03-14
Filing date: 1973-04-27
Publication date: 1974-09-10
Anticipated expiration: 1991-09-10

Abstract

There is disclosed a parachute-borne flare assemblage air-lifted by being fired from a rifled gun barrel. This assemblage comprises a hollow projectile which houses the flare package proper. The package includes the flare composition, a main parachute for supporting the flare composition, a drag parachute for reducing the forward velocity and brake flaps for reducing the spin velocity imparted to the projectile when fired and thus also to the flare package and persisting after ejection of the flare package from the projectile. The flare package is ejected as a unit from the projectile by an ejection charge a predetermined time after firing of the projectile, or in other words, when the projectile has reached a selected point in its trajectory. Further ejection and ignition charges free at timed intervals the brake flaps for reducing the spin velocity and the drag chute for reducing the forward velocity of the ejected flare package. Also at timed intervals, components jacketing the package while in the projectile are released and thrown clear by the centrifugal force acting upon these components after ejection from the projectile. Finally, the main parachute unfolds and supports the flare composition which is ignited by an ignition charge, the ignition of which is initiated by the firing of the ejection charge ejecting the flare package as a unit from the projectile.

Description

Unite Simmons States Patent [191 PARACHUTE-BORNE FLARE ASSEMBLAGE [75] Inventor: Bjorn Herman 0101 Simmons,

Karlskoga, Sweden [73] Assignee: Aktiebolaget Bofors, Bofors, Sweden [22] Filed: Apr. 27, 1973 [21] Appl. No.: 355,057

Related US. Application Data [63] Continuation-in-part of Ser. No. 341,071, March 14, 1973, which is a continuation of Ser. No. 101,499, Dec. 28, 1970, abandoned.

[52] US. Cl l02/35.4, 102/344, 102/37.1

[51] Int. Cl. F42b 13/38 [58] Field of Search 102/34.l, 34.4, 34.5, 35, 102/354, 35.6, 37.1; 244/138 [56] References Cited UNITED STATES PATENTS 2,785,632 3/1957 Clauser et a1 l02/37.6

3,055,300 9/1962 Stoehr 102/354 3,702,588 11/1972 Simmons 102/356 3,719,339 3/1973 Simmons et a1. l02/35.6

Primary ExaminerRobert F. Stahl Attorney, Agent, or Firml-lane, Baxley & Spiecens [57] ABSTRACT There is disclosed a parachute-borne flare assemblage air-lifted by being fired from a rifled gun barrel. This assemblage comprises a hollow projectile which houses the flare package proper. The package includes the flare composition, a main parachute for supporting the flare composition, a drag parachute for reducing the forward velocity and brake flaps for reducing the spin velocity imparted to the projectile when fired and thus also to the flare package and persisting after ejection of the flare package from the projectile. The flare package is ejected as a unit from the projectile by an ejection charge a predetermined time after firing of the projectile, or in other words, when the projectile has reached a selected point in its trajectory. Further ejection and ignition charges free at timed intervals the brake flaps for reducing the spin velocity and the drag chute for reducing the forward velocity of the ejected flare package. Also at timed intervals, components jacketing the package while in the projectile are released and thrown clear by the centrifugal force acting upon these components after ejection from the projectile. Finally, the main parachute unfolds and supports the flare composition which is ignited by an ignition charge, the ignition of which is initiated by the firing of the ejection charge ejecting the flare package as a unit from the projectile.

7 Claims, 9 Drawing Figures PAIENTEUSEP 10 I974 3.834.312

SHEET 1 OF 2 /0 3 j f pof f za /l A AA JIIL FIG. I

?ATENTED 3E? 10 3,834,312

SHEET 2 OF 2 1 PARACI-IUTE-BORNE FLARE ASSEMBLAGE BACKGROUND It is desired that flare assemblages of the general kind above referred to become effective at a preselected level and above a preselected ground or target area.

There are known various types of parachute-borne flare assemblages which are air-lifted by packaging the entire assemblage in a hollow projectile and firing the projectile from a rifled barrel. Such firing inherently introduces several problems. Firing of a projectile from a rifled barrel imparts to the projectile and thus also the flare package, not only a forward velocity but also the high spin velocity as is necessary to stabilize the projectile in its trajectory. Obviously, the flare composition and its parachute cannot be made operational immediately after ejection from the projectile, as the then still persisting forward velocity and spin velocity would act upon the composition and the parachute with such force that the flare and its parachute are likely to be destroyed or at least very much damaged.

Another inherent problem is that the ejection of the flare package from the projectile and the subsequent release of the parachute for supporting the flare composition and the ignition of the flare composition must be so timed that ideally the flare becomes operational exactly above the preselected ground area or target, and also has a minimal or no forward speed at all (disregarding wind action) so that it will illuminate the desired ground area or target as long as it continues to burn and slowly drifts down.

Finally, it is desirable that rendering the flare package fully operational after ejection thereof from the projectile is completed at a minimum of time so that a moment of surprise is obtained.

None of the parachute-borne flare assemblages as heretofore known fully satisfy the aforepointed out requirements.

THE INVENTION It is an object of the invention to provide a novel and improved parachuteborne flare assemblage of the general kind above referred to which automatically causes reduction of the spin velocity and of the forward velocity of the flare package after ejection thereof from the projectile before the parachute for supporting the flare after ignition thereof is freed for unfolding.

Another object of the invention is to provide a novel and improved parachute-borne flare assemblage of the general kind above referred to in which means for reducing the spin velocity and means for reducing the forward velocity are successively released after ejection of the flare package as a unit from the projectile, and in which such release is controlled by firing at selected time intervals ejection charges and ignition charges carried within the projectile and within the flare package.

Still another object of the invention is to provide a novel and improved parachute-bome flare assemblage of the general kind above referred to so that all the components of the assemblage other than the flare composition and the parachute therefor are automatically and rapidly ejected from the path of the flare composition and its parachute after ejection of the flare package from the rojectile, thereby assuring that none of these components can damage the flare composition or its parachute after the components have served their purpose.

BRIEF SUMMARY OF THE INVENTION The aforepointed out objects, features and advantages, and other objects, features and advantages which will be pointed out hereinafter are obtained by providing a hollow projectile open at its tail end and arranged for firing from a rifled barrel. A flare package is housed in the projectile, the bottom end of which is closed by a plate capable of sustaining the heavy gas pressures which it must sustain when the projectile is fired. The flare package comprises in alignment a flare composition, a main parachute secured to the flare composition and a drag parachute. The flare composition is placed in a cannister closed at one end and open at its other end. A sleeve formed of lengthwise sections extends at one end into the cannister and terminates at its other end short of the bottom plate. This sleeve houses the main parachute and the drag parachute, the latter being rotatably secured to a mounting disc which in turn is releasably retained within the sleeve. The sections forming the sleeve are initially held together-by an inwardly protruding flange formed at the sleeve end protruding into the cannister and engaged with a groove in a mounting disc securing the main parachute to the flare composition. The other ends of the sleeve sections are held together by a flanged ring overlying these ends. The sleeve has secured thereto a brake means in the form of flaps which are initially folded back upon the outside of the sleeve wall and unfold when exposed to the centrifugal force. The flaps are retained in their folded position by the projectile wall when and while the flare package is housed in the projectile. Readying of the package for operation is started by ejecting the flare package as a unit from the projectile, the bottom plate being knocked out by this ejection. This stage and all subsequent stages are controlled by successively firing ejection charges and ignition charges. The ejection charge which initiates the ejection of the package from the projectile is self-activating and set to fire a predetermined time after firing of the projectile. This time is so set that ejection of thepackage is initiated at a point in the trajectory of the projectile which is selected with respect to the intended target area so that the flare becomes effective above the target area with reasonable accuracy. Firing of the first charge causes expulsion of the flare package as a unit from the projectile casing by pushing out the bottom plate. The firing of the first charge also initiates the firing of a timed delay charge which in turn initiates the firing of a second ejection charge and of an ignition charge for igniting the flare composition. Upon ejection of the flare package as a unit, the brake flaps are released, thereby rapidly reducing the spin velocity of the package and the drag parachute is also freed'to effect reduction of the forward velocity. Firing of the second ejection charge expels the flare composition from the cannister and also frees the sections of the sleeve. These sections will fly apart carrying with them the brake flaps out of the path of the flare composition and the main parachute. The drag parachute is also freed to remove itself from the path of the flare composition and the main parachute which in turn is free to unfold. The flare is ignited by its ignition means and is now supported by its parachute.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing, a preferred embodiment of the invention is shown by way of illustration and not by way of limitation.

In the drawing:

FIG. 1 is a lengthwise sectional view of a flare assemblage according to the invention;

FIGS. 2 to 6 show successive stages of the release of a flare package from a projectile in which it has been carried aloft;

FIG. 7 is a view of the flare in its fully operational stage;

FIG. 8 is a fragmentary enlarged sectional view of a component of the flare package; and

FIG. 9 is a fragmentary perspective view of another portion of the component of FIG. 8.

DETAILED DESCRIPTION OF THE DRAWING Referring now to the figures more in detail, and first to FIG. I, the flare assemblage exemplified in this figure comprises a hollow projectile casing 1 which is designed to be fired from a rifled barrel such as a gun barrel and is provided for this purpose with a conventional band or ring la. Firing of the projectile from such rifled barrel imparts to the projectile the required forward velocity and spin velocity. The open bottom end of the projectile is closed by a bottom plate 2 which is releasably seated in the projectile casing and designed to be capable of sustaining the heavy gas pressures to which it is exposed when the projectile is fired.

The space within the projectile accommodates the flare package 3. This package comprises in an aligned array a body of a suitable and conventional flare composition 4, a main parachute and a drag parachute 6. The main parachute is secured to one end of the flare composition by a mounting means in the form of a disc 7. The drag parachute is secured to a second mounting means in the form of a disc 8 by a rotatable fastening means 9 such as a ball bearing to avoid twisting of the guy wires of the drag parachute, as will be more fully explained hereinafter.

The flare composition 4 is housed in a tubular cannister 10 closed by an end wall 11 at its end facing the nose of the projectile. The main parachute and the drag parachute are housed in a sleeve 15 which is shown in greater detail in FIGS. 8 and 9. The sleeve is formed of two or more lengthwise sections 15a, four such sections being indicated by way of example in FIG. 9. The aforereferred to mounting disc 8 is releasably retained in position by sleeve 15. There is shown in the inner wall of the sleeve a groove 16 engaged with a peripheral flange 17 or other protrusion on disc 8. The sleeve sections extend at one end into the open end of cannister 10 underlying the wall thereof. The sleeve sections are releasably held together at this end by means of an inwardly directed protrusion such as a flange 18 engaged with a matching groove 19 in mounting disc 7. Similarly, the sleeve sections are held together at their other ends by a ring 22, which preferably has an angular cross-sectional outline as it is best shown in FIG. 8; flange 22a of the ring overlying the peripheral outside of sleeve sections 15a. The diameter as defined by the inner end of the other flange of the ring 22 is less than the diameter of flange 17 on disc 8, for a purpose which will become apparent hereinafter. The retaining ring 22 is not secured to the sleeve sections, but is held in position by the adjacent wall portion of the projectile 1, as it is clearly shown in FIG. 1.

It is essential for smooth and rapid readying of the flare package for operation that the very high spin velocity which the flare package has when it is ejected from the projectile as will be more fully explained hereinafter, is reduced to an acceptable value as otherwise the drag parachute the purpose of which is to reduce the forward velocity of the package to an acceptable value could not function but would become twisted. For this purpose brake means are mounted on the outside of sleeve 15. There are shown in FIG. 9 four brake flaps 23, one associated with each of the four sections 15a. Each of the flaps is pivotal about a shaft 24 mounted on the respective section lengthwise thereof. The flaps have a curvature matching the curvature of the sleeve so that they can be folded into an inactive position substantially flush with the peripheral outline of the sleeve sections. If desired and as indicated in FIG. 9, a peripheral groove 24a may be provided in the outer sleeve wall. As it is shown in FIG. 1, the brake flaps are so located that they are held in the folded position by the respective inner wall portion of the projectile when and while the flare package is housed in the projectile.

The flare package further comprises a first ejecting means 25 such as a time-delayed charge, a first timedelayed ignition means 26 disposed between charge 25 and end wall 11 of the cannister, a second time-delayed ejecting means 27 disposed within the cannister adjacent to one end of flare composition body 4, and a second time-delayed ignition means 28 for igniting the flare composition at the respective end thereof.

The time-delayed ejecting means and ignition means as herein referred to are well known in the ordnance field. Ejection charges and ignition charges having any desired delay factor are readily available. The present invention is not concerned with any specific and novel structure of such charges, but merely with the use thereof. Hence, they are not described in detail.

As has been pointed out previously, the purpose of the projectile is to air-lift the flare package to a selected level and near a selected ground area or target, and the purpose of the flare package itself is to reach its fully effective condition shown in FIG. 7 as closely to the selected area or target as possible, and also as rapidly as possible.

Turning now to FIGS. 2 to 6, it is assumed that the projectile has been fired and reached in its trajectory the location at which the flare package is to be re leased. The delay time of ejection charge 25 is set so that it fires at that moment. As it is shown in FIG. 2, the gas pressure generated by the firing of the charge ejects the flare package as a unit from the projectile thereby expelling bottom plate 2. As it is evident, it is essential that plate 2 be rapidly removed out of its position of axial alignment with the projectile, or in other words out of the trajectory of the projectile, to provide a clear exit for the flare package. To effect such removal, the

spin velocity of the plate which of course persists after expulsion of the plate from the projectile is utilized by forming the plate with an unbalanced or asymmetric distribution of weight for instance, by placing the center of gravity of the plate eccentric with respect to its center axis. Such dislocation of the center of gravity in conjunction with the spin velocity of the plate will cause the same to be propelled laterally relative to the projectile thereby clearing the open end of the projectile and avoiding damage to components of the flare package as the same emerge from the projectile and are successively released, as will be more fully described hereinafter.

Turning to FIG. 3, according to this figure ejection of the flare package still as a unit has progressed far enough to free brake flaps 23 from the projectile casing. As a result, the centrifugal force acting upon the flaps will automatically and rapidly force the same from the initial inactive or folded position into the braking position shown in FIG. 3 and also in FIG. 9.

FIG. 4 shows the operational stage in which the flared package is fully ejected from the projectile casing. The brake flaps being extended reduce the spin velocity of the package to an acceptable value and the brake parachute is fully unfolded thereby rapidly reducing the forward velocity of the flared package to an acceptable value. The term acceptable value for the forward and spin velocities is not and cannot be a fixed value for flare packages in general, but is selected in accordance with the specific requirements of the flared package involved. Such selection does not present any difficulties to experts in the art.

Firing of charge 25, in addition to expelling the flare package as a unit from the projectile, also causes ignition of the time-delayed ignition charge 26 by the hot gases generated by firing of charge 25. Ignition of charge 26 in turn initiates firing of ejection charge 27 and of charge 28 for igniting the flared composition.

Firing of charge 27 ejects the flare composition 4 from cannister 10. The resulting stage of operation is shown in FIG. 5. The centrifugal force now free to act on sections 15a of sleeve 15 causes flange 18 to leave groove 19 in mounting disc 7. Mounting disc 8 of the drag parachute is also freed by disengaging of its flange 17 from groove 16.

As a result, sections 150 of sleeve 15 fly apart and the drag parachute with its mounting disc attached thereto and also holding ring 22 being caught by disc 8 are freed to move clear from the flare composition body and the main parachute 5 supporting the composition.

This stage of operation is shown in FIG. 6. This figure also indicates that the flare composition has been ignited by ignition means 28.

The main parachute will now unfold fully and support the burning flare composition as is shown in FIG. 7 which illustrates the final operational stage.

As is evident from the previous description, the time intervals between successive stages of operation are controlled by the settings of ejecting and ignition means 25, 26, 27 and 28. Timing of these ejecting and ignition means is so selected that ideally the flare package becomes effective above the selected ground area or target and also at a minimum time from the firing of the projectile.

While the invention has been descfibed in detail with respect to a certain now preferred example and embodiment of the invention, it will be understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed is: l. A parachute-borne flare assemblage, said assemblage comprising in combination:

a hollow projectile casing open at its bottom end and arranged for firing from a rifled barrel; and a flare package housed within said projectile casing, said flare package including in alignment: a flare composition body; a main parachute and a drag parachute, the flare composition facing the nose end of the projectile casing; a tubular cannister closed by an end wall at its end facing the projectile nose and open at the other end and a tubular sleeve composed of lengthwise sections, said cannister housing the flare composition and the sleeve housing the parachutes, one end of the sleeve extending into the open cannister end and the other end terminating short of the end of the projectile; a first mounting means securing the flare composition to the main parachute and a second mounting means rotatably mounting the drag parachute, said second mounting means being releasably engaged with the inner wall of said sleeve; a first retaining means releasably retaining the ends of the sleeve sections underlying the cannister wall and a second retaining means releasably retaining the sleeve sections at the other end thereof; brake means for reducing the spin velocity of the flare package, said brake means being movable from an inactive position substantially flush with the outer sleeve wall into a braking position outwardly spaced from said wall and mounted on an outer wall portion of the sleeve underlying the projectile casing wall but clear of the cannister wall thereby retaining the brake means in said inactive position; and a time-delayed self-activating first ejecting charge means interposed in a closed space defined within the projectile casing between the nose end thereof and the closed cannister end, a time-delayed first ignition charge means interposed in said casing space between said first time-delayed ejecting charge means and the cannister end wall, a second time-delayed ejecting charge means within the cannister in a closed space between the closed cannister end and the adjacent end of the flare composition, said first and second ejecting charge means being disposed closely adjacent to the cannister end wall and in substantial opposition, and a second time-delayed ignition charge means interposed between said sec ond ejecting charge means and the adjacent end of the flare composition for igniting the same, activation of said first ejecting charge means ejecting the flare package as a unit from the projectile casing generating hot gases thereby freeing the brake means for movement into the braking position and also freeing the drag parachute for unfolding and further causing ignition of the first ignition charge means, ignition of said first ignition charge means activating the second ejecting means through said cannister end wall and activation of the second ejecting means igniting the second ignition charge means, activation of the second ejecting charge means expelling the flare composition, the first mounting means and the first retaining means from the cannister, thereby freeing the sleeve sections from retention by the first and the second retaining means, freeing of the sleeve sections causing separation thereof thereby freeing the second mounting means and thus the drag parachute and also freeing the main parachute for unfolding and ignition of the second ignition charge means igniting the flare composition at the end of the delay time of said second time-delayed ignition charge means.

2. The flare assemblage according to claim 1 wherein a bottom plate is releasably seated in the open end of the projectile, the weight distribution of said bottom plate being asymmetric so as to cause lateral movement of the plate relative to the center axis of the projectile casing by the persisting spin velocity of the plate after ejection thereof from the projectile casing.

3. The flare assemblage according to claim 1 wherein said sleeve has a peripheral groove in its inner wall surface, said mounting means for the drag parachute being releasably engaged with said groove.

4. The flare assemblage according to claim 1 wherein said first retaining means comprise an inwardly extending protrusion at said one end of the sleeve and a peripheral groove in the mounting means for the main parachute, said protrusion being releasably engaged with said groove.

5. The flare assemblage according to claim 1 wherein said second retaining means comprise a ring having a peripheral flange overlying the outside of the sleeve at the other end thereof.

6. The flare assemblage according to claim 5 wherein the inner peripheral outline of said ring is smaller than the outer peripheral outline of said mounting means for the drag parachute.

7. The flare assemblage according to claim 1 wherein said brake means for reducing the spin velocity of the flare package after ejection thereof from the projectile as a unit comprise flaps each associated with one of the sleeve sections, and a holding means for each of the flaps, each of said holding means including a pivot shaft extending parallel to the length of the respective sleeve section and mounting a flap at one end thereof, said flaps having a curvature matching the curvature of the sleeve for initially holding the flaps in a position substantially flush with the outer peripheral outline of the sleeve, action of the centrifugal force upon ejection of the flare package as a unit from the projectile casing causing pivoting of the flaps into an outwardly protruding braking position.

* l= l l=

Claims

1. A parachute-borne flare assemblage, said assemblage comprising in combination: a hollow projectile casing open at its bottom end and arranged for firing from a rifled barrel; and a flare package housed within said projectile casing, said flare package including in alignment: a flare composition body; a main parachute and a drag parachute, the flare composition facing the nose end of the projectile casing; a tubular cannister closed by an end wall at its end facing the projectile nose and open at the other end and a tubular sleeve composed of lengthwise sections, said cannister housing the flare composition and the sleeve housing the parachutes, one end of the sleeve extending into the open cannister end and the other end terminating short of the end of the projectile; a first mounting means securing the flare composition to the main parachute and a second mounting means rotatably mounting the drag parachute, said second mounting means being releasably engaged with the inner wall of said sleeve; a first retaining means releasably retaining the ends of the sleeve sections underlying the cannister wall and a second retaining means releasably retaining the sleeve sections at the other end thereof; brake means for reducing the spin velocity of the flare package, said brake means being movable from an inactive position substantially flush with the outer sleeve wall into a braking position outwardly spaced from said wall and mounted on an outer wall portion of the sleeve underlying the projectile casing wall but clear of the cannister wall thereby retaining the brake means in said inactive position; and a time-delayed self-activating first ejecting charge means interposed in a closed space defined within the projectile casing between the nose end thereof and the closed cannister end, a time-delayed first ignition charge means interposed in said casing space between said first time-delayed ejecting charge means and the cannister end wall, a second time-delayed ejecting charge means within the cannister in a closed space between the closed cannister end and the adjacent end of the flare composition, said first and second ejecting charge means being disposed closely adjacent to the cannister end wall and in substantial opposition, and a second time-delayed ignition charge means interposed between said second ejecting charge means and the adjacent end of the flare composition for igniting the same, activation of said first ejecting charge means ejecting the flare package as a unit from the projectile casing generating hot gases thereby freeing the brake means for movement into the braking position and also freeing the drag parachute for unfolding and further causing ignition of the first ignition charge means, ignition of said first ignition charge means activating the second ejecting means through said cannister end wall and activation of the second ejecting means igniting the second ignition charge means, activation of the second ejecting charge means expelling the flare composition, the first mounting means and the first retaining means from the cannister, thereby freeing the sleeve sections from retention by the first and the second retaining means, freeing of the sleeve sections causing separation thereof thereby freeing the second mounting means and thus the drag parachute and also freeing the main parachute for unfolding and ignition of the second ignition charge means igniting the flare composition at the end of the delay time of said second time-delayed ignition charge means.