EP0455550B1 - Dispositif d'étanchéité d'un projectile flèche - Google Patents

Dispositif d'étanchéité d'un projectile flèche Download PDF

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Publication number
EP0455550B1
EP0455550B1 EP19910401127 EP91401127A EP0455550B1 EP 0455550 B1 EP0455550 B1 EP 0455550B1 EP 19910401127 EP19910401127 EP 19910401127 EP 91401127 A EP91401127 A EP 91401127A EP 0455550 B1 EP0455550 B1 EP 0455550B1
Authority
EP
European Patent Office
Prior art keywords
sabot
penetrator
insert
shoe
elastomer
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
EP19910401127
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0455550A1 (fr
Inventor
Marc Berville
Joel Leblond
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.)
Giat Industries SA
Original Assignee
Giat Industries SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Giat Industries SA filed Critical Giat Industries SA
Publication of EP0455550A1 publication Critical patent/EP0455550A1/fr
Application granted granted Critical
Publication of EP0455550B1 publication Critical patent/EP0455550B1/fr
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
    • F42B14/00—Projectiles or missiles characterised by arrangements for guiding or sealing them inside barrels, or for lubricating or cleaning barrels
    • F42B14/06—Sub-calibre projectiles having sabots; Sabots therefor
    • F42B14/061—Sabots for long rod fin stabilised kinetic energy projectiles, i.e. multisegment sabots attached midway on the projectile
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B14/00—Projectiles or missiles characterised by arrangements for guiding or sealing them inside barrels, or for lubricating or cleaning barrels
    • F42B14/06—Sub-calibre projectiles having sabots; Sabots therefor
    • F42B14/067—Sealing aspects in sabots, e.g. sealing between individual segments of the sabots or sealing between the outer surface of the sabot and the inner surface of the barrel

Definitions

  • the technical sector of the present invention is that of arrow projectiles comprising a penetrator and a shoe, and in particular means for sealing between the shoe and the penetrator.
  • Document EP-A-0183892 describes a molded elastomeric shutter, constituted by a ring secured to radial arms.
  • the ring takes place in a groove common to the hoof and the indenter, the arms being trapped in grooves formed at the joint planes of the various elements of the hoof.
  • the grooves open into the groove of the belt which thus completes the tightness of the system.
  • This solution is a variant of an earlier method, known to those skilled in the art, which consisted in injecting an elastomer into these same grooves and grooves.
  • EP-A-0306615 relates to a process consisting of using a specially designed tool, to overmold a sealing film behind the shoe.
  • An O-ring prevents the sealant from entering between the shoe and the projectile. In this way, the drawbacks mentioned above are avoided.
  • we are forced to seal on a complete projectile, that is to say in which the indenter and shoe are assembled (the same applies to the other methods mentioned above). After opening, there remains an elastomer residue of random geometry glued to the back of the indenter and which can disturb the external ballistics.
  • constraints related to occupational safety and health may arise from the fact that sometimes heavy metals are used, such as uranium, and sometimes pyrotechnic elements (tracers or destabilization devices in exercise shots for example). Hence the interest in avoiding the manipulation of indenters.
  • Document DE-A-3332675 (preamble of claim 1) describes a rear seal for a boom munition which has one or more lips coming to bear on the bar.
  • the seal also includes an insert, metallic or not, on which the elastic material of the seal is vulcanized.
  • the joint is then made integral with the shoe by screwing or else by gluing.
  • the sealing device according to the invention does not imply the presence of residual elastomer on the indenter which avoids disturbances in the path of the indenter.
  • the length L1 of the cylindrical part of the insert is substantially greater than or equal to the diameter of the indenter.
  • the frustoconical part has an apex angle of between 6 and 10 ° and a length L2 greater than or equal to the diameter of the indenter.
  • the threaded cylindrical part of the insert has a production tolerance between the average tolerance and the minimum material of the thread of the indenter.
  • the invention relates to a sealing device obtained by the above method, characterized in that an elastomer ring partially fills the profile of the thread of the shoe.
  • the invention also relates to a sealing device obtained by the aforementioned method, characterized in that radial grooves are arranged in the thread at the level of the joint surfaces of the shoe, these grooves being filled with the elastomer element.
  • the radial grooves are arranged in the thread at the level of the shoe joint planes, the grooves being filled by the elastomer element.
  • the elastomer element has a Shore duration greater than or equal to 70 and an elongation before rupture less than or equal to 250%.
  • the lip of the elastomer element has an edge with a thickness H of between 10 and 15% of the diameter of the indenter.
  • a result of the present invention lies in the fact that the seal is produced at the rear part of the shoe, by deformation of the elastomer lip and elastic support thereof on the indenter.
  • Another result lies in the use of the pressure of the propellant gases to increase the contact of the elastomer element on the indenter.
  • Another result lies in the absence of tearing residues adhering to the penetrator, a source of disruption of its trajectory.
  • An arrow munition comprises, as shown in FIG. 1, a penetrator 1, made of uranium for example, equipped with a shoe 2.
  • the shoe and the penetrator are connected in known manner by a thread 3.
  • the rear part of the shoe carries a elastomeric element 4 which extends from the penetrator 1 to the belt 5 of the shoe.
  • the elastomer element 4 comprises a lip 6 in elastic support on the penetrator 1.
  • the elastomeric element does not adhere to the indenter and does not remain attached to the latter at the time of the shoe-indenter separation.
  • the diameter of the rear cylindrical part of the indenter (on which the lip 6 bears) is slightly less than the diameter of the thread, which allows the insertion of the indenter into the shoe by screwing by introducing the indenter through the front part of the shoe.
  • the lip 6 is not damaged by the thread and it deforms elastically so as to be applied to the rear cylindrical part of the indenter.
  • FIG. 2 shows an enlarged view of the lip 6, shown at rest, that is to say the penetrator removed.
  • This lip has a length L3 projected onto the axis X′X of the ammunition greater than or equal to the outside diameter of the indenter, an edge 10 of thickness H between 10 and 15% of the diameter of the indenter and the end wall of which delimits by with respect to a perpendicular to the axis X′X an angle ⁇ 3 of the order of 15 °.
  • the external surface 11 of the lip 6 defines with the axis X′X an angle ⁇ 1 less than or equal to 30 ° and the internal surface 12 an angle ⁇ 2 between 4 and 25 °.
  • the elastomer enters the thread 14 of the shoe and partially covers the teeth of the latter.
  • the thickness and the length of the elastomer ring 13 are shown diagrammatically in FIG. 2.
  • Figure 2a shows more precisely the profile of the thread 14, the sides 16 and vertices 17 of the teeth are covered with an elastomer layer of the order of a few tenths of a mm (0.2 to 0.6 mm).
  • the total length of the crown 13 is of the order of 2 to 10 times the length of the thread pitch (i.e. for a pitch of 4 mm: a length of 8 to 40 mm), and it is interrupted irregularly by because of the manufacturing process described below.
  • the seal 4, the lip 6 and the crown 13 are preferably obtained by vulcanization, the particular mode of manufacture proposed by the invention will be described below.
  • the elastomer it must have the following mechanical characteristics: Shore hardness ⁇ 70 and elongation before rupture ⁇ 250%.
  • the vulcanization conditions must not exceed 135 ° C for 20 minutes so as not to cause annealing of the hoof (generally carried out in 7049 A according to the US MIL standard).
  • the product sold under the brand name "ALCANSYL 538" marketed by the company SAFIC ALKAN gives good results.
  • the elastomer must adhere perfectly to the shoe and to the material of the belt, over the entire contact surface. To this end, the affected surfaces of the shoe should be coated with a bonding agent.
  • the nature of this product is to be defined as a function of the elastomer, and falls within the domain of the know-how of the skilled person responsible for the overmolding operation.
  • the adhesion agent sold under the brand THIXON 305 marketed by WHITTAKER CORPORATION has given satisfaction.
  • Figure 3 shows a step in the manufacturing process where the indenter was replaced by an insert 7 to perform the overmolding.
  • the mold in which the vulcanization takes place is not shown in detail, it comes to conform to the rear shape of the shoe 2 while providing the space necessary for making the joint.
  • a part 19 on which a bottom 20 is fixed, for example by means of screws, and which receives the shoe.
  • a part 18 is made integral with the part 19 by known means, not shown, such as screws or flanges.
  • the part 18 carries one or preferably several injection orifices 21, and one or more radial orifices 22 allowing the evacuation of the air during the injection.
  • This insert 7 is subsequently removed to allow the penetration device 1 to be put in place.
  • the profile of the lip 6 at the level of the penetrator must be such that the pressure of the propellant gases of the projectile tends to press said lip 6 onto the penetrator 1. It it is also necessary to tighten this lip 6 on the indenter 1. To this end, in order to achieve a tightening as homogeneous as possible, taking into account the external profile of the shoe 2 and that of the overmolding which results therefrom, the insert 7 must have a taper at the lip 6.
  • FIG. 4 represents the insert 7 alone, consisting of a threaded cylindrical part 8 and a frustoconical part 9.
  • the part 8 has a nominal outside diameter identical to that of the indenter 1 and a length L1 greater than or equal to the outside diameter , i.e. 10 to 20 times the thread pitch.
  • Part 9 has a length L2 at least equal to the width of the lip 6 that is to be obtained, an apex angle between 6 and 10 ° and a diameter D, in line with the end of the lip, equal at 8 to 13% of the outside diameter of the part 8.
  • the thread of the insert has a profile identical to that of the indenter, but the tolerance for making the thread is preferably between the average tolerance and the minimum material of the thread of the indenter.
  • minimum material means the minimum diameter of the thread of the indenter (minimum tolerance).
  • the average tolerance is the arithmetic mean value between the maximum and minimum values of the diameter of the indenter thread.
  • This crown improves gas tightness.
  • the choice of the length L1 of the insert greater than or equal to the diameter of the indenter is important because it creates a distance of travel of the elastomer during molding such that it does not extend beyond the insert and does not does not come to fill all the tapping of the shoe.
  • part 9 In the case where part 9 is cylindrical, its diameter will be chosen equal to 8 to 13% of the diameter of part 8.
  • the elastomer must adhere perfectly to the shoe and the material of the belt, over the entire contact surface. On the other hand, it must in no way remain stuck to the insert so as not to cause degradation during demolding.
  • the surfaces concerned should be coated with suitable products, namely a bonding agent for the shoe and a release agent for the insert.
  • suitable products namely a bonding agent for the shoe and a release agent for the insert.
  • the nature of these products is to be defined as a function of the elastomer, and falls within the domain of the know-how of the person skilled in the art responsible for the overmolding operation.
  • the adhesion agent sold under the brand THIXON 305 marketed by WHITTAKER CORPORATION
  • the release agent sold under the brand SIPIOL C have given satisfaction.
  • the insert can be positioned either from the front or from the rear of the shoe; similarly, it can be removed after vulcanization by the front of the shoe, which has the advantage of not passing the threaded part of the insert over the lip 6.
  • Figures 5 to 6 illustrate an alternative embodiment according to which the shoe has radial grooves 15 disposed at the joint planes of the different sectors of the shoe. These grooves will have a length less than or equal to a fraction of L3, and a depth of the order of a millimeter.
  • the elastomer When the elastomer is overmolded, the latter will penetrate into the grooves just as it enters between the insert and the shoe to form the crown 13.
  • the adhesion agent will have been deposited beforehand in the grooves and will ensure the holding elastomer on the shoe material at this level.
  • the advantage of such a configuration is on the one hand to improve the mechanical strength of the lip 6 relative to the shoe by providing it with additional attachment points on the shoe at the thread, and on the other hand improve the tightness at the joint surfaces of the shoe segments.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)
  • Injection Moulding Of Plastics Or The Like (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
EP19910401127 1990-05-04 1991-04-29 Dispositif d'étanchéité d'un projectile flèche Expired - Lifetime EP0455550B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9005676A FR2661739A1 (fr) 1990-05-04 1990-05-04 Dispositif d'etancheite d'un projectile fleche.
FR9005676 1990-05-04

Publications (2)

Publication Number Publication Date
EP0455550A1 EP0455550A1 (fr) 1991-11-06
EP0455550B1 true EP0455550B1 (fr) 1995-07-05

Family

ID=9396359

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910401127 Expired - Lifetime EP0455550B1 (fr) 1990-05-04 1991-04-29 Dispositif d'étanchéité d'un projectile flèche

Country Status (4)

Country Link
EP (1) EP0455550B1 (enrdf_load_stackoverflow)
JP (1) JPH0682198A (enrdf_load_stackoverflow)
DE (1) DE69110970T2 (enrdf_load_stackoverflow)
FR (1) FR2661739A1 (enrdf_load_stackoverflow)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6279214B1 (en) * 1999-07-14 2001-08-28 Alliant Techsystems Inc. Moisture seal for composite sabot with depleted uranium penetrator
FR2948185A1 (fr) 2009-07-20 2011-01-21 Nexter Munitions Dispositif de liaison par concordance de forme entre un sabot et un barreau d'un projectile
FR2987891B1 (fr) 2012-03-06 2014-09-26 Nexter Munitions Projectile sous calibre a structure de tete amenagee
FR3039266B1 (fr) 2015-07-22 2017-09-01 Cime Bocuze Penetrateur comportant un coeur entoure d'une gaine ductile et procede de fabrication d'un tel penetrateur
FR3110687B1 (fr) 2020-05-20 2022-05-27 Nexter Munitions Projectile sous calibré et procédé de neutralisation d'un objectif en mettant en oeuvre un tel projectile.
DE102020004709A1 (de) 2020-08-04 2021-08-05 Bundesrepublik Deutschland, vertr. durch das Bundesministerium der Verteidigung, vertr. durch das Bundesamt für Ausrüstung, Informationstechnik und Nutzung der Bundeswehr Penetrator für ein unterkalibriges Wuchtgeschoss

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH495547A (de) * 1968-05-31 1970-08-31 Rheinmetall Gmbh Flügelstabilisiertes Unterkalibergeschoss
NL174873C (nl) * 1972-07-22 1984-08-16 Rheinmetall Gmbh Sub-kaliber projectiel met staartvinnen.
DE3332675C2 (de) * 1983-09-10 1986-10-02 Rheinmetall GmbH, 4000 Düsseldorf Heckseitige Dichtscheibe aus elastischem Material für einen Treibkäfig
DE3730370A1 (de) * 1987-09-10 1989-03-23 Rheinmetall Gmbh Verfahren zur herstellung von treibkaefiggeschossen
US4838168A (en) * 1988-02-17 1989-06-13 Honeywell, Inc. Ultraviolet cured gas seal for discarding sabot projectile

Also Published As

Publication number Publication date
JPH0682198A (ja) 1994-03-22
DE69110970T2 (de) 1995-12-14
DE69110970D1 (de) 1995-08-10
EP0455550A1 (fr) 1991-11-06
FR2661739A1 (fr) 1991-11-08
FR2661739B1 (enrdf_load_stackoverflow) 1994-07-13

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