US3791300A

US3791300A - Flare shell

Info

Publication number: US3791300A
Application number: US00286420A
Authority: US
Inventors: J Prochnow; W Simon
Original assignee: Rheinmetall GmbH
Current assignee: Rheinmetall Industrie AG
Priority date: 1971-09-04
Filing date: 1972-09-05
Publication date: 1974-02-12
Anticipated expiration: 1991-02-12
Also published as: GB1344786A; DE2144400A1; FR2155240A5; IL40155A0

Abstract

The invention concerns a flare shell, from the base of the case of which an internal appliance, consisting of a drogue parachute, a main parachute and a flare set, is ejected by means of an ejection charge which detonates the flare set, the internal appliance first being brought to a low speed of flight by the drogue parachute, whereupon the main parachute unfolds and floats to earth with the flare set.

Description

Proclmow et a1.

tes ,&

[111 351,399 Feb. 12, 11974 FLARE SHELL [75] Inventors: Jurgen Prochnow, Dusseldorf;

Walter Simon, Laurenberg/Aachen,

both of Germany [73] Assignee: Rheinrnetall GmbH, Dusseldorf,

Germany [22] Filed: Sept. 5, 1972 [21] Appl. No.: 286,420

[30] Foreign Application Priority Data Sept. 4, 1971 Germany 2144400 [52] US. Cl. l02/35.6, 102/87 [51] Int. Cl. F42!) 13/38 [58] Field of Search 102/87, 90, 35, 35.2, 35.4, 102/35.6, 34.4, 37.6, 49.4, 49.5; 89/1 B [56] References Cited UNITED STATES PATENTS 3,362,290 1/1968 Carr et a1 l02/49.5 X 3,055,300 9/1962 Stoehr 102/35.4

Robertson et a1. 102/35.4

2,124,876 7/1938 Driggs, Jr 102 35 x 1,365,865 1/1921 Svejda 102/35.6

2,342,096 2 1944 Zimmerman. 102/35.6

3,633,456 1/1972 Carr et a1. 102/495 3,119,298 1/1964 Brown 102/49.s

FOREIGN PATENTS OR APPLICATIONS 651,935 4/1951 England l02/35.6

Primary Examiner-Benjamin A. Borchelt Assistant ExaminerH. .1. Tudor Attorney, Agent, or Firm-Williamson, Bains & Moore TRACT The invention concerns a flare shell, from the base of the case of which an internal appliance, consisting of a drogue parachute, a main parachute and a flare set, is ejected by means of an ejection charge which detonates the flare set, the internal appliance first being brought to a low speed of flight by the drogue parachute, whereupon the main parachute unfolds and floats to earth with the flare set.

5 Claims, 5 Drawing Figures FLARE SHELL BRIEF SUMMARY OF THE INVENTION Flare shells stabilized by rifling and fins, as well as flare shells and flare bombs in which, after completion of a predetermined time or distance of flight, the useful charge consisting of a flare body is ejected are known. Because of the danger, associated with such shells and bombs, of the supporting parachute, ejected at high speed, being damaged as a result of wind forces suddenly acting on it, or that it may become unusable as a result of the holding straps being torn off, the drogue parachute, now introduced, has proved a valuable addition to the parachute system. The function of this comparatively small drogue parachute, made of strong cloth and fitted with strong carrier straps, is that of reducing the speed of the ejected internal appliance of the shell to such an extent that the main parachute is able to unfold freely without the risk of damage, so as to float slowly to earth with the flare set.

The drogue parachute, designed to resist high wind forces, naturally requires a large cavity in the shell and this means reduction of the usefull load. Therefore, in the case of a flare rocket, it has been proposed to use, instead of one drogue parachute, two small drogue parachutes which likewise unfold one after the other, but only occupy the packing space of a single drogue parachute. Also provided is a very complicated mechanism for opening the individual parachutes, which mechanism enables the various operations to take place in a precisely timed manner. Thus for example, in this three-parachute system, the internal appliance, consisting of the flare body and the three parachutes, is ejected from the shell case by means of a powder charge detonated by a shell-like time fuse, the internal appliance'eing trapped by the first drogue parachute.

By means of a built-in rotor, which is started up when a predetermined minimum speed is reached, a hitherto locked detonating pin can cause a powder charge to be detonated, and this ejects the first drogue parachute together with the carrier plate and the rotor. At the same time the second drogue parachute unfolds and in fact acts as an auxiliary parachute for further reducing the velocity of the flare body, but the main function of this second drogue parachute is to pull the main parachute out of the case in a reliable manner as a result of the tractive force imparted by the wind to said second drogue parachute. Since the various operations are initiated by time-responsive and speed-responsive detonators, it is possible to determine with some reliability the moment at which the main parachute comes into use.

An advantage of this system resides in the fact that the flare set begins to burn as soon as the ejection charge adjacent the flare set has left the shell case.

The disadvantages of these known flare rockets are very expensive and complicated means which, in the proposed combination, cannot be used in the case of a shell stabilized by means of rifling. Furthermore, the ratio of the space occupied by the successive arrangement of the three parachutes and the rotor to the space occupied by the useful load is so unfavourable, that for this reason it is not possible to apply this system to rifled shells.

Also known is a fin-stabilized flare shell in which there is fitted adjacent the nose fuse a central detonating tube which extends to the rearward end of the shell and there detonates the ejection charge. After ejectionv of the internal appliance comprising two parachutes, first the drogue parachute unfolds andthis in turn entrains the main parachute. With this relatively simple parachute system for a flare shell, it is only possible to predetermine the moment of ejection but not the moment at which the flare set, ignited by the nose fuse, is taken over by the main parachute and begins to float to earth. v

The above-mentioned defects and difficulties are avoided by the invention, the object of which is so to improve a flare shell that the moment at which the internal appliance is ejected and the parachute opened can be accurately predetermined prior to firing the shell by the use of simple and robust means. A further object of the invention is to enable said means to be used in the case of shells that are stabilized by means of rifling and fins, as well as in rockets.

According to theinvention, this object is achieved by the main parachute and the flare set each being surrounded by a sleeve, the two sleeves being fitted one behind the other and a separable connection being provided between them, which connection is separable by means of a pressure plate bearing against the rim of the base of the sleeve for the main parachute, in that the pressure plate is acted upon by the compressed gases from a separating change detonated by way of delay means by the ejection charge.

A further feature of the invention is that the pressure plate, provided with an anchoring means for the main parachute, bears in the uninfluenced condition against a push-in cover disc sealing the sleeve for the flare set and is axially spaced from the cover disc by means of a plurality of spacer blots secured at the cover disc side, the arrangement being such that when the separating charge is detonated, the sleeve surrounding the main parachute is ejected by the pressure plate, but the latter continues to be concentrically guided on the turnedover rim of the cover disc.

According to the invention, a cavity is provided for receiving the separating charge between the push-in cover disc and the pressure plate which incorporates a bent-away portion in its median zone.

Finally, the separating charge can be detonated by a time fuse which is held by a detonating tube which extends centrally through the flare set and projects through a central orifice in the push-in cover disc.

By means of this simple construction of flare ammunition, the various operations, such as ejection after a predetermined period of distance of flight, opening of the drogue parachute and opening of the main parachute after a predetermined minimum speed has been attained, can be effected in a very precisely timed manner.

An advantageous embodiment of the invention and further advantages attainable by means of it will emerge from the following more detailed description relating to the annexed drawing, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal section through a flare shell;

FIG. 2-shows the flare shell after ejection of the internal appliance;

parachute immediately prior to the unfolding of the main parachute, and

FIG. 4 and show a connection between the flare set and the main parachute before and after the packing sleeve for the parachute has sprung open.

DETAILED DESCRIPTION The flare shell, the sleeve 1 of which is provided with a guide ring 1a for the purpose of stabilization by means of rifling, can, when fitted with the same internal appliance, also be used as a flare bomb or flare rocket or as a tin-stabilized shell. The nose of the shell carries a time fuse 2 followed, along the axis of the shell, by an ejection charge 3 which is limited by a cover 4 which seals off the entire internal appliance. This cover 4 which may be formed as a separate part or as the end closure for a sleeve 5 surrounding the flare set 6, has a central hole in which a detonating tube 8 containing a time fuse 7 is fitted. The detonating tube 8 extends over the entire length of the flare set 6 and terminates in a hole in apush-in cover disc 9 which constitutes the second end closure for the sleeve 5 containing the flare set, the cover 4 being the other closure member for this sleeve. The opening in the base of a parachute-packing sleeve 10 is surrounded by the turned over rim 9a of disc 9. A nonreleasable connection if formed between the turned-over rim 9a and the sleeve 5 for the flare set. A plurality of radial shear pins 11 distributed circumferentially serve as releasable coupling means joining the base of inner end of sleeve 10 and the adjacent end of flare set sleeve 5, with shear pins 11 extending radially into rim 9a of cover disc 9 for this purpose. Between the rim of the base of the sleeve 10 for a parachute 17 and the push-in cover disc 9 is inserted a pressure plate 12 which is loosely connected in the axial direction with said cover disc by a plurality of spacer bolts 13 screwed against said cover disc. The shanks of the spacer bolts 13 which carry heads 130 are of such size that after the radial pins 1 1 have sheared, the packing sleeve 10 is ejected, but the pressure plate 12 is held to cover disc 9 by its turned-over rim 9a and by bolts 13. Between the push-in cover disc 9 and the pressure plate 12, which is provided with a bent-away or recessed portion 12a in its median zone, is a cavity 14 for receiving a separating charge 15 which is fitted immediately in front of the detonating tube 8 carrying the time fuse 7. Screwed into the central hole in the pressure plate l2 is a carrier knob 16 in which all the carrier straps of a main parachute 17 are held in a bunch. The main parachute l7 fills the sleeve 10. Mounted on the packing-sleeve cover 18, which bears against the base lb of the shell case 1 through two or more annular segments 19, is a carrier knob 20 which holds the drogue parachute 21 accommodated in a relatively small cavity between the cover 18 and the base 1b.

The mode of operation is as follows:

After the flare shell has been fired and after a predetermined flight time has elapsed or a predetermined distance of flight covered, the ejection charge 3 is detonated by a fuse or by a detonator pin. The resultant gas pressure suffices to cause rearward ejection of the entire internal appliance including the base lb of the shell with those portions of the shellcase 1 where the fracture is intended to occur adhering to it;'thus, not only are the flare set 6 and the time fuse 7 in the detonating tube 8 detonated, but the drogue parachute 21 is able to unfold. The entire internal appliance now hangs from the drogue parachute 21 which performs the function of considerably reducing the velocity derived 7 from the shell. The flight time of the drogue parachute 21 is largely determined by the delay time of the fuse 7 in the detonating tube 8. This time is of such length that even when special atmospheric conditions are taken into account, the drogue parachute will have reached a relatively low velocity when the burning fuse 7 detonates the separating charge 15. The gas pressure that builds up in the cavity 14 pushes the pressure plate 12 so far forward that the latter takes up a position in which, as show in FIG. 5, it is axially spaced from the push-in cover disc 9. In this situation, the bottom rim of the packing sleeve 10 is released when the radial pins 11 shear, so that the main parachute 17 is slowly extracted from its packing sleeve 10 by the weight of the flare set 6 hanging from the parachute. Careful release is further promoted by the fact that opening takes place on the leeward side. The damage-preventing measures enable light parachute materials to be used, so that the main parachute 17 made thereof can be larger in size and can thus be made more efficient as regards its carrying power.

All the details and features disclosed herein, and particularly the spatial and constructive arrangements disclosed are claimed as being important to the invention in so far as, singly or in combination, they are novel to the prior art.

We claim:

1. In a flare shell having a casing containing an internal appliance comprised of a drogue parachute, a main parachute and a flare set ejectable from the base of the casing, and a fuse actuated ejection charge which detonates the flare set and ejects the appliance from the base of the casing, after which the internal appliance is first brought to a low speed of flight by the drogue parachute, whereupon the main parachute unfolds and floats to earth with the flare set, the improvement comprising:

a first sleeve embracing said main parachute and having said drogue parachute attached to the rear end thereof;

a second sleeve embracing said flare set, said sleeves being in longitudinal alignment one behind the other within said casing with said second sleeve positioned forwardly of said first sleeve, and the forward end of said flare set disposed in proximity to said ejection charge in the front end of said casing for direct ignition thereby;

releasable coupling means joining adjacent ends of said sleeves, whereby said sleeves and said main parachute and said flare set contained therein are ejectable as a unit from said casing;

a displaceable pressure plate positioned between said adjacent ends of said sleeves and bearing against one end of said first sleeve at the end thereof adjacent to one end of said second sleeve;

a separating charge for separating said sleeves positioned to exert an explosive force on said pressure plate in such a manner that said coupling means is released by the action of said pressure plate on said one end of said first sleeve under the pressure of gases generated by said separating charge to separate said sleeves; and

time delay igniting means operatively associated with said separating charge for the ignition thereof and positioned within said casing in proximity to said ejection charge so as to be directly actuated by the detonation of said ejection charge, whereby the detonation of said ejection charge simultaneously ignites said flare set. ejects the double sleeve flare set and parachute unit from the shell casing to deploy the drogue chute and actuates said time delay igniting means for the subsequent ignition of said separating charge.

2. A flare shell as defined in claim 1 wherein:

said pressure plate is positioned transversely with respect to the longitudinal axis of said sleeves and has a carrier knob thereon to which said main parachute is attached; and

a cover disc sealing the end of said second sleeve adjacent to said first sleeve end, said pressure plate being attached to said cover disc by spacer means permitting axial displacement of said pressure plate with respect to said disc along the longitudinal axis of said sleeves, whereby upon detonation of said separating charge, said first sleeve is separated and ejected by said pressure plate, which remains attached to said second sleeve.

3. A flare shell as defined in claim 2 wherein:

said pressure plate is recessed to provide a cavity within which'said separating charge is contained between said pressure plate and said cover disc.

4. A flare shell as defined in claim 1 wherein:

said separating charge is located between said adjacent ends of said sleeves; and said time delay igniting means comprises a time fuse contained within a detonating tube extending longitudinally through said flare set from a point adjacent said ejection charge to a point at the rear end of said flare set in proximity to said separating charge.

5. A flare shell as defined in claim 2 wherein:

said spacer means comprises a plurality of spacer bolts extending parallel to the longitudinal axis of said sleeves from points within said first sleeve, through said pressure plate, to points of attachment to said cover disc, said spacer bolts being of predetermined length to permit the displacement of said pressure plate a sufficient distance along the longitudinal axis of said sleeves to release said coupling means, and thereby eject and separate said first sleeve.

Claims

1. In a flare shell having a casing containing an internal appliance comprised of a drogue parachute, a main parachute and a flare set ejectable from the base of the casing, and a fuse actuated ejection charge which detonates the flare set and ejects the appliance from the base of the casing, after which the internal appliance is first brought to a low speed of flight by the drogue parachute, whereupon the main parachute unfolds and floats to earth with the flare set, the improvement comprising: a first sleeve embracing said main parachute and having said drogue parachute attached to the rear end thereof; a second sleeve embracing said flare set, said sleeves being in longitudinal alignment one behind the other within said casing with said second sleeve positioned forwardly of said first sleeve, and the forward end of said flare set disposed in proximity to said ejection charge in the front end of said casing for direct ignition thereby; releasable coupling means joining adjacent ends of said sleeves, whereby said sleeves and said main parachute and said flare set contained therein are ejectable as a unit from said casing; a displaceable pressure plate positioned between said adjacent ends of said sleeves and bearing against one end of said first sleeve at the end thereof adjacent to one end of said second sleeve; a separating charge for separating said sleeves positioned to exert an explosive force on said pressure plate in such a manner that said coupling means is released by the action of said pressure plate on said one end of said first sleeve under the pressure of gases generated by said separating charge to separate said sleeves; and time delay igniting means operatively associated with said separating charge for the ignition thereof and positioned within said casing in proximity to said ejection charge so as to be directly actuated by the detonation of said ejection charge, whereby the detonation of said ejection charge simultaneously ignites said flare set, ejects the double sleeve flare set and parachute unit from the shell casing to deploy the drogue chute and actuates said time delay igniting means for the subsequent ignition of said separating charge.

2. A flare shell as defined in claim 1 wherein: said pressure plate is positioned transversely with respect to the longitudinal axis of said sleeves and has a carrier knob thereon to which said main parachute is attached; and a cover disc sealing the end of said second sleeve adjacent to said first sleeve end, said pressure plate being attached to said cover disc by spacer means permitting axial displacement of said pressure plate with respect to said disc along the longitudinal axis of said sleeves, whereby upon detonation of said separating charge, said first sleeve is separated and ejected by said pressure plate, which remains attached to said second sleeve.

3. A flare shell as defined in claim 2 wherein: said pressure plate is recessed to provide a cavity within which said separating charge is contained between said pressure plate and said cover disc.

4. A flare shell as defined in claim 1 wherein: said seParating charge is located between said adjacent ends of said sleeves; and said time delay igniting means comprises a time fuse contained within a detonating tube extending longitudinally through said flare set from a point adjacent said ejection charge to a point at the rear end of said flare set in proximity to said separating charge.

5. A flare shell as defined in claim 2 wherein: said spacer means comprises a plurality of spacer bolts extending parallel to the longitudinal axis of said sleeves from points within said first sleeve, through said pressure plate, to points of attachment to said cover disc, said spacer bolts being of predetermined length to permit the displacement of said pressure plate a sufficient distance along the longitudinal axis of said sleeves to release said coupling means, and thereby eject and separate said first sleeve.