US3702588A - Device for a flare - Google Patents

Device for a flare Download PDF

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Publication number
US3702588A
US3702588A US98725A US3702588DA US3702588A US 3702588 A US3702588 A US 3702588A US 98725 A US98725 A US 98725A US 3702588D A US3702588D A US 3702588DA US 3702588 A US3702588 A US 3702588A
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US
United States
Prior art keywords
flaps
parachute
body member
flap
flare
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US98725A
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English (en)
Inventor
Bjorn Herman Olof Simmons
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Saab Bofors AB
Original Assignee
Bofors AB
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Filing date
Publication date
Application filed by Bofors AB filed Critical Bofors AB
Application granted granted Critical
Publication of US3702588A publication Critical patent/US3702588A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B10/00—Means for influencing, e.g. improving, the aerodynamic properties of projectiles or missiles; Arrangements on projectiles or missiles for stabilising, steering, range-reducing, range-increasing or fall-retarding
    • F42B10/02—Stabilising arrangements
    • F42B10/14—Stabilising arrangements using fins spread or deployed after launch, e.g. after leaving the barrel
    • F42B10/16—Wrap-around fins
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B12/00—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material
    • F42B12/02—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the warhead or the intended effect
    • F42B12/36—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the warhead or the intended effect for dispensing materials; for producing chemical or physical reaction; for signalling ; for transmitting information
    • F42B12/56—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the warhead or the intended effect for dispensing materials; for producing chemical or physical reaction; for signalling ; for transmitting information for dispensing discrete solid bodies
    • F42B12/58—Cluster or cargo ammunition, i.e. projectiles containing one or more submissiles
    • F42B12/62—Cluster or cargo ammunition, i.e. projectiles containing one or more submissiles the submissiles being ejected parallel to the longitudinal axis of the projectile

Definitions

  • ABSTRACT A braking device for a flare unit including a combustible flare composition attached to a parachute which unit is ejected from a missile a predetermined period of time after firing of the missile and after ejection spins at a high speed about its lengthwise axis, brakes the spinning motion of the unit to a predetermined maximal rotational speed.
  • the braking device comprises flaps which are initially folded one upon another and upon the body of the flare unit and are unfolded by the centrifugal force acting upon the flaps due to the spinning of the unit after the ejection thereof.
  • the present invention relates to a device for a flare that can be enclosed in a projectile, particularly a pyrotechnical flare, which is separated from the projectile at a given time after this has been fired, the flare, at the separation, then being given a rotation around an axis of symmetry extending in the longitudinal direction of the flare.
  • the flare is moreover to be provided with a member for braking said rotation, consisting of two or more flaps, symmetrically arranged in relation to the circumference of the flare and as a rule in the vicinity of the envelope surface of the flare and/or its extension, each flap then being arranged in a bearing so that in connection with said separation it will be turned out or folded out by the centrifugal force caused by the rotation.
  • a member for braking said rotation consisting of two or more flaps, symmetrically arranged in relation to the circumference of the flare and as a rule in the vicinity of the envelope surface of the flare and/or its extension, each flap then being arranged in a bearing so that in connection with said separation it will be turned out or folded out by the centrifugal force caused by the rotation.
  • a flap of the design described above must be made so that it does not extend far tangentially, i.e. it must be made so that, when raised, it does not extend far radially. Hoping to be able to increase the braking effect with a flap that has this extremely limiting factor, it has hitherto been proposed, for the purpose of obtaining compensation, to give the flap a great extension axially.
  • the width of the tongue where it is fastened has had to be increased as described above, which has involved the above-mentioned drawbacks and limitations at the dimensioning of the projectile and the flare, as an extension of the longitudinal bearing axles will take up some of the space available for, for instance, the flare.
  • the present invention gives an indication of a device that permits flaps with a design that gives the optimum braking effect shortest possible braking time) even when there are comparatively high centrifugal loads on the flap, which makes it possible, for instance, to have all ammunition of this kind provided with a common type of flap, without having to employ special designs in individual cases of the flap or its fastening means with consideration to the rotation that occurs.
  • the device according to the invention provides for a flap that is extremely suitable for use for projectiles with both low and high rotating speeds.
  • the drawbacks of having material that is difficult to work with and is expensive are eliminated, and the careful inspection procedure that thas hither-to been necessary can be practically omitted.
  • a flap comprises two sheetformed parts which extend from the bearing and at least partly cover each other, which moreover are joined together at the bearing along one of their end edges and that the two parts are also made in such a way that a difference between the total centrifugal load on one part and the total centrifugal load on the other part is zero or is less than or equal to a bending resistance of the material used for the parts, and a further resistance caused by the parts possibly being fastened together, so that, at the rotation, the parts remain in a predetermined position.
  • FIG. 1 shows in perspective, examples of the positioning in principle of four flaps on a flare unit
  • FIG. 2 in a side view shows the fastening of the flaps in a member attached to the flare, whereby the flaps will be arranged in the vicinity of the extension of the envelope surface of the flare;
  • FIG. 3 is a side view and in cross-section shows a cross-section of the device according to the invention.
  • FIG. 4 in a diagram form shows examples of the braking time for a device of a known design and a device according to the invention.
  • FIG. 1 shows a unit containing a flare unit, separated from a projectile after this has been fired, which unit is then rotating around an axis of symmetry 2 which it has been given.
  • the unit has a member for braking up the rotation in the form of four flaps 3, symmetrically arranged around its circumference, which are raised at or after the separation, which are located in the vicinity of the envelope surface 4 of the flare unit by being somewhat recessed in relation to this.
  • the recess in question can be made greater or lesser.
  • a centrifugal force caused by the rotation actuates the flaps, and depending upon, for instance, the rotating speed, the air stream and the material used in the flaps, these will extend from the unit to a greater or lesser extent in relation to what is indicated in FIG. 1.
  • An arrow Rp indicates the direction of rotation of the unit.
  • FIG. 2 is intended to show the fastening of the flaps 3 to the unit with the flare unit that can be separated from the projectile in more detail.
  • the flare 5 and the parachute 6 of the flare unit are held together by a container 7, a carrying member 8 and a plate 9.
  • the unit formed by the parts 5-9 rotates as indicated above around its axis of symmetry 2, and the movement of the unit along its axis of symmetry 2 is braked by a brake parachute which is released at the separation, and the cords of which are indicated by 10.
  • the brake parachute is attached to the parts 5-9 via a ball bearing 11.
  • the flaps 3 are fastened and somewhat recessed in the member 8, and will thereby be movably arranged at the extension of the envelope surface 12 of the flare. It is, of course, possible to recess the flaps further in the carrying member 8, but such a measure would reduce the space available for the parachute 6. On the contrary, in the example of the embodiment, the endeavour is to have the flaps recesses as little as possible, and there are therefore essential requirements that they can be made with little thickness.
  • the parts 5-9 are kept together until the braking has been completed, when a delay composition 13 on one end of the container 7 achieves a separation of the flare unit (flare 5 and parachute 6) from the other said parts of the unit, at the same time as ignition of the flare takes place, which can thereafter descend to the ground, depending from its parachute 6.
  • FIG. 3 shows a cross-section of the bearing for the flap and its fastening in relation to the carrying member 8.
  • the bearing consists of a bearing axle 14 which extends in the recess of the carrying member, substantially parallel with the envelope surface 12 of the flare (FIG. 2).
  • the flap 3 then consists of two sheet-formed parts 15 and 16, which extend from the bearing so that they cover each other, the parts also being joined together at the bearing along one of their end edges 15 and 16a.
  • the sheet-formed parts 15 and 16 will consequently extend one from each side 17 and 18, respectively, of the bearing axle 14, and in the example of the embodiment, the parts, for the rest, are substantially identical, at the same time as the sections that are located outside the bearing can be fastened together, for instance by spot welding, soldering or glueing.
  • the parts 15 and 16 appropriately consist of a sheet of steel or light metal placed under the bearing 14, and are then bent around the bearing so that their ends will correspond to the parts 15 and 16.
  • one of the parts 15 of the two parts and/or the other part 16 can follow the surface or the bearing axle to a greater or lesser extent.
  • the parts 15 and 16 can be designed so that, when turned down, they conform to the shape of the outer surface of the carrying member.
  • the two parts 15 and 16 are also designed in such a way that any difference between the total centrifugal load on one side, for instance 15, and the total centrifugal load on the other side 16 is less than or equal to a bending resistance in the material used for the parts so that, at the rotation, the parts will remain in a predetermined position.
  • the resistance from the fastening together in conjunction with said bending resistance of the material, will contribute by absorbing any possible difference in centrifugal load, and it is thereby possible to allow one of the sheet-formed parts to extend outside the other sheet-formed part, for instance so that in a simple way it will be possible to obtain a thinner outer part of the flap in question for overlapping of two flaps.
  • FIG. 3 also shows, with dash lines, a flap in the raised position, which coincides with the direction of a total force Tp acting upon the flap, which is determined by the air-stream force Ap as well as the centrifugal load Cp on the flap. Examples of said forces are given with a force parallelogram at the raised flap indicated with dash lines.
  • HO. 4 shows the braking time in a diagram form for a flare unit which, as the separation from the projectile, has been given a rotating speed of 9,000 r.p.m. and a velocity of 300 m/sec.
  • the rotation of the flare should be reduced to, for instance, 500 r.p.m. and the velocity to 60 m/sec., which values can be obtained within approx. 8 sec. with a previously known device, see curve 19, within such a short time at less than 2 sec. with the device according to the invention, of which an example is given by curve 20.
  • the invention is not limited to the embodiments shown above as examples, but can be subjected to modifications within the scope of the following claims.
  • the invention is not limited to the number of flaps on the flare.
  • the design of the flaps and their location are not essential for the concept of the invention, and it has no significance whether or not there are one or several flaps on the same bearing.
  • the bearing should consist of a clamping recess in the carrying member from which the sheetformed parts extend as described above, which flaps will then be turned or folded out.
  • the invention can also be used for smoke or gas developing compositions.
  • each of said pivot means including a pivot pin extending transversely of the lengthwise axis of said body member, the two layers of each flap straddling at one end the respective pin and envelope the same, said pins constituting pivot axes for pivotal movements of the flaps between an inactive position in which the flaps are folded upon the circumferential surface of the body member and a spread-apart braking position in which the flaps define an angle with said surface, the flaps being in said inactive position prior to the application of a spin velocity to the projectile and in said braking position when the projectile is in flight due to the centrifugal force then acting upon the flaps;
  • the aerodynamic configuration of said flaps being such that the differential between the centrifugal forces acting upon opposite sides of the flaps does not exceed the inherent bending resistance of the material of which the flaps are made.
  • each of said pivot means comprises a lengthwise elongate groove in the circumferential surface of said body member, each of said grooves having a substantially circular cross-sectional outline con- 5 structed at the surface of the body member, the respective end of the flaps terminating in an enlarged edge fitted in said grooves for retention therein.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Toys (AREA)
  • Braking Arrangements (AREA)
US98725A 1970-01-08 1970-12-16 Device for a flare Expired - Lifetime US3702588A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE00147/70A SE339646B (enrdf_load_stackoverflow) 1970-01-08 1970-01-08

Publications (1)

Publication Number Publication Date
US3702588A true US3702588A (en) 1972-11-14

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Family Applications (1)

Application Number Title Priority Date Filing Date
US98725A Expired - Lifetime US3702588A (en) 1970-01-08 1970-12-16 Device for a flare

Country Status (7)

Country Link
US (1) US3702588A (enrdf_load_stackoverflow)
DE (1) DE2100489C3 (enrdf_load_stackoverflow)
FR (1) FR2075263A5 (enrdf_load_stackoverflow)
GB (1) GB1304671A (enrdf_load_stackoverflow)
IL (1) IL35877A (enrdf_load_stackoverflow)
NL (1) NL7100151A (enrdf_load_stackoverflow)
SE (1) SE339646B (enrdf_load_stackoverflow)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3834312A (en) * 1973-03-14 1974-09-10 Bofors Ab Parachute-borne flare assemblage
US4004514A (en) * 1976-01-20 1977-01-25 The United States Of America As Represented By The Secretary Of The Navy Roll rate stabilized wrap around missile fins
US4013009A (en) * 1974-02-08 1977-03-22 Etat Francais Illuminating projectiles and pyrotechnic devices
US4023495A (en) * 1975-04-26 1977-05-17 Rheinmetall G.M.B.H. Twist brakes for projectiles
US4572463A (en) * 1981-09-20 1986-02-25 Aryeh Ashkenazi Telescopic projectile and apparatus for firing same
US4829903A (en) * 1986-12-01 1989-05-16 Aktiebolaget Bofors Ammunition device
US5117731A (en) * 1991-11-04 1992-06-02 The United States Of America As Represented By The Secretary Of The Navy Tactical acoustic decoy
US20030146342A1 (en) * 2000-03-21 2003-08-07 Ulf Hellman Fin-stabilised artillery shell
US6745978B1 (en) * 2003-03-24 2004-06-08 At&T Corp. Aerodynamic stabilization of a projectile
US6978968B1 (en) 2003-03-24 2005-12-27 At&T Corp. Deployable flare for aerodynamically stabilizing a projectile
US20070075183A1 (en) * 2005-06-07 2007-04-05 Diehl Bgt Defence Gmbh & Co., Kg Wing arrangement as well as a missile
US8816261B1 (en) * 2011-06-29 2014-08-26 Raytheon Company Bang-bang control using tangentially mounted surfaces
US9989338B2 (en) * 2014-02-26 2018-06-05 Israel Aerospace Industries Ltd. Fin deployment system
US20190137246A1 (en) * 2016-04-06 2019-05-09 Bae Systems Bofors Ab Parachute device for a divisible shell
US20200033104A1 (en) * 2018-03-28 2020-01-30 Ascendance International, LLC Long range large caliber frangible round for defending against uavs

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE353956B (enrdf_load_stackoverflow) * 1971-06-24 1973-02-19 Bofors Ab
SE416235B (sv) * 1976-12-27 1980-12-08 Bofors Ab Bromsanordning for roterande kropp
DE3422231A1 (de) * 1984-06-15 1985-12-19 Diehl GmbH & Co, 8500 Nürnberg Einrichtung zum aerodynamischen abbremsen der rotationsbewegung eines koerpers
DE3435420A1 (de) * 1984-09-27 1986-04-03 Rheinmetall GmbH, 4000 Düsseldorf Gefechtskopf
NL192056C (nl) * 1985-03-12 1997-01-07 Eurometaal Nv Cilindervormige houder van metaal met rotatieremflappen.
GB8609166D0 (en) * 1986-04-15 1986-09-17 British Aerospace Deployment arrangement for spinning body
GB9015445D0 (en) * 1990-07-13 1991-02-20 Royal Ordnance Plc Projectile surveillance apparatus
CH685069A5 (de) * 1991-12-18 1995-03-15 Contraves Ag Unterkalibriges, flügelstabilisiertes Geschoss, das mit Drall verschossen wird.
SE508857C2 (sv) 1997-03-25 1998-11-09 Bofors Ab Fenstabiliserad base-bleedgranat
SE508858C2 (sv) * 1997-03-25 1998-11-09 Bofors Ab Fenstabiliserad granat
SE521445C2 (sv) 2001-03-20 2003-11-04 Bofors Defence Ab Sätt att synkronisera fenutfällningen vid en fenstabiliserad artillerigranat samt en i enlighet därmed utformad artillerigranat

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US17407A (en) * 1857-05-26 Improved projectile for killing whales
US617376A (en) * 1899-01-10 Railroad signal-fusee
US2599703A (en) * 1949-09-02 1952-06-10 Bendix Aviat Corp Lockout warning system for home heating apparatus
US3165281A (en) * 1962-07-11 1965-01-12 Werner J V Gohlke Elastic folding control surfaces for aerodynes
US3578796A (en) * 1968-09-25 1971-05-18 Thiokol Chemical Corp Spinning and stabilizing system for solid propellant rocket or missiles

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US17407A (en) * 1857-05-26 Improved projectile for killing whales
US617376A (en) * 1899-01-10 Railroad signal-fusee
US2599703A (en) * 1949-09-02 1952-06-10 Bendix Aviat Corp Lockout warning system for home heating apparatus
US3165281A (en) * 1962-07-11 1965-01-12 Werner J V Gohlke Elastic folding control surfaces for aerodynes
US3578796A (en) * 1968-09-25 1971-05-18 Thiokol Chemical Corp Spinning and stabilizing system for solid propellant rocket or missiles

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3834312A (en) * 1973-03-14 1974-09-10 Bofors Ab Parachute-borne flare assemblage
US4013009A (en) * 1974-02-08 1977-03-22 Etat Francais Illuminating projectiles and pyrotechnic devices
US4023495A (en) * 1975-04-26 1977-05-17 Rheinmetall G.M.B.H. Twist brakes for projectiles
US4004514A (en) * 1976-01-20 1977-01-25 The United States Of America As Represented By The Secretary Of The Navy Roll rate stabilized wrap around missile fins
US4572463A (en) * 1981-09-20 1986-02-25 Aryeh Ashkenazi Telescopic projectile and apparatus for firing same
US4829903A (en) * 1986-12-01 1989-05-16 Aktiebolaget Bofors Ammunition device
US5117731A (en) * 1991-11-04 1992-06-02 The United States Of America As Represented By The Secretary Of The Navy Tactical acoustic decoy
US6779754B2 (en) * 2000-03-21 2004-08-24 Bofors Defence Ab Fin-stabilized artillery shell
US20030146342A1 (en) * 2000-03-21 2003-08-07 Ulf Hellman Fin-stabilised artillery shell
US6745978B1 (en) * 2003-03-24 2004-06-08 At&T Corp. Aerodynamic stabilization of a projectile
US6978968B1 (en) 2003-03-24 2005-12-27 At&T Corp. Deployable flare for aerodynamically stabilizing a projectile
US20070075183A1 (en) * 2005-06-07 2007-04-05 Diehl Bgt Defence Gmbh & Co., Kg Wing arrangement as well as a missile
US8816261B1 (en) * 2011-06-29 2014-08-26 Raytheon Company Bang-bang control using tangentially mounted surfaces
US9989338B2 (en) * 2014-02-26 2018-06-05 Israel Aerospace Industries Ltd. Fin deployment system
US20190137246A1 (en) * 2016-04-06 2019-05-09 Bae Systems Bofors Ab Parachute device for a divisible shell
US10458765B2 (en) * 2016-04-06 2019-10-29 Bae Systems Bofors Ab Parachute device for divisible shell
US20200033104A1 (en) * 2018-03-28 2020-01-30 Ascendance International, LLC Long range large caliber frangible round for defending against uavs
US10753715B2 (en) * 2018-03-28 2020-08-25 Ascendance International, Llc. Long range large caliber frangible round for defending against UAVS
US11047657B2 (en) 2018-03-28 2021-06-29 Ascendance International, LLC Long range large caliber frangible round for defending against UAV'S

Also Published As

Publication number Publication date
DE2100489C3 (de) 1975-07-17
IL35877A (en) 1974-05-16
FR2075263A5 (enrdf_load_stackoverflow) 1971-10-08
DE2100489B2 (enrdf_load_stackoverflow) 1974-11-28
DE2100489A1 (de) 1971-07-15
GB1304671A (enrdf_load_stackoverflow) 1973-01-24
IL35877A0 (en) 1971-04-28
NL7100151A (enrdf_load_stackoverflow) 1971-07-12
SE339646B (enrdf_load_stackoverflow) 1971-10-11

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