FR2626069A1 - BALL FOR REDUCED SHOT MUNITIONS OF PLASTIC MATERIAL AND METHOD FOR MANUFACTURING THE SAME - Google Patents

Abstract

The invention relates to a reduced firing bullet comprising a body 1 of low density plastic material and a guide belt 2 of higher density, characterized in that the belt is made of plastic material loaded with solid particles and containing particles of solid. 'a lubricant. The bullet according to the invention is produced by a biinjection process. Application to small caliber reduced fire for training or close combat.

Description

The present invention relates to a ball for

  reduced firing rates of plastic material and its manufacturing process. The field of application of the invention relates more particularly to small caliber reduced fire (5.56 per

  example), for training or close combat, count-

  given the range limitation required for the ball.

  The balls known in this kind of application are

globally of two types.

  Some, marketed under the name BALPLAST, are based on plastic material of the polyamide type with a density of 1, overmolded on a metal belt.

  made, for example, of copper, brass or tombac.

  This metal belt has a dual function.

  Firstly, it promotes the scratching of the barrel of the weapon by ensuring on the one hand the seal between the bullet and the inside of the barrel and also preventing the fouling of the barrel by the plastic material since it tends to suppress the contact between the plastic material and

inside the barrel.

  Secondly, this belt has the role of

  the ball to make it more stable on its trajectory.

  However, this type of metal belt ball

has disadvantages.

  On the one hand, this metal belt is

  tible to peel off the plastic material, as a result of

  linkage, especially in rotation, which can lead to

  a destabilization of the trajectory of the ball. A fragment

  may also be caused at the moment of firing

  because of the heterogeneity of the ball.

  On the other hand, the accuracy of the shot can be affected by the lack of concentricity of the belt and the body of

the ball.

  Finally, its manufacturing process is quite complex implementation: the belt must be made beforehand accurately, and its positioning in the mold before overmolding by injection must be equally accurate, -2-

  these operations require many manipulations.

  Also, is the productivity of this process limited?

  the cost of the ball is relatively high.

  The other type of ball proposed more recently is

  described in FR-A-2,528,564.

  It is an exercise ball made entirely

  metal-filled plastic material containing a lubricant, the content of the particles being

  such that the density of the bullet is between 3 and 5.

  One of the disadvantages of this bullet, lacking

  belt, lies in the limited number of parameters, to

  see shape and density, acting on its performance

  ballistic because of its monobloc character.

  Another disadvantage is that its cost remains high due to the exclusive use of a plastic material

charged expensive.

  The object of the invention is to propose balls

  plastic material for reduced fire or rapid combat

  proxies which are reliable and adjustable ballistic characteristics in a wide range for these types of jobs, and

  whose production process ensures a good reproducibility

  low cost of production.

  The ballistic characteristics of the balls according to the invention have the following advantages: - sufficient precision at a limited distance chosen

  (eg 100 m), comparable to that of a war ball.

  re, which implies good stability on the initial part.

the trajectory.

  - adjustable limitation of the range (for example

  500 m), lower than that of a war ball, which

  plic a destabilization of the ball beyond the distance

accurate shooting.

- weak vulnerant effect.

  According to the invention, these characteristics

  Ballistics are easily and inexpensively obtained by

  vary the geometry of the ball, its center of gravity,

  its density and its moments of longitudinal and transverse inertia

  sal and consequently the report of these.

  To this end, the invention relates to a bullet for reduced fire ammunition comprising a body of material

  low-density plastic and a den-guide belt

  higher density, characterized in that the belt is

  made of plastic material loaded with solid particles and

  containing particles of a lubricant.

  The subject of the invention is also a process for

  ball-making using bi-rotating presses

  injection and characterized in that it comprises the following steps: 1) injection molding the plastic composition constituting the belt, then in the same cycle, 2) injection molding the body of the ball in

  the space remains free, the belt being kept in

fixed in the mold.

  Other features and advantages of the invention

  will appear in the following description of examples not

  limiting, with reference to the figures among which: - Figures 1 and 2 are schematic sections

  longitudinal examples of balls according to the invention.

  According to a preferred embodiment of the invention, the body of the ball is made of plastic material of a

density close to 1.

  This plastic material may be a polyamide, especially

  known under the trade name RILSAN, presenting

  the physical and mechanical characteristics set out in

  after, or any other material with similar characteristics: - density at 23 ° C: 1.04 +.0.02 - melting temperature: 183 to 187 ° C - tensile characteristics at 23 ° C: yield stress:> 40 MPa tensile strength:> 37 MPa elongation at break:> 250%

  The belt made of plastic material

  solids has a density of between 2 and 6 and

preferably, close to 4.

  The solid particles are made of metal such as copper or lead, alloy such as bronze or metal oxide such as lead oxide. They are preferably

  consisting of bronze balls of a diameter

be 0.01 and 0.1 mm.

  The plastic material loaded with the belt

  also contains a solid lubricant. This one is preferred

  essentially molybdenum disulfide.

  The parameters affecting the ballistic characteristics of the ball can be adjusted according to the intended use by varying the geometry of the belt (height, thickness, positioning relative to the body of the ball).

  the ball), as well as the nature and composition of

  constituent parts of the body and the belt.

  In particular, the presence of solid particles in the belt makes it possible to ballast the plastic material and to obtain the desired density for the bale by varying the content of solid particles. This density may vary

  in a wide range from 1.2 to 5, and preferably from 2 to 3.

  Experience shows that these solid particles suf-

  strive to get the stripe taken from the barrel of the weapon and em-

  fish the fouling of the latter.

  A perfect connection between the plastic material of the body of the bullet and the belt is ensured by the manufacturing process, in particular by reflow on the surface of the belt during the injection of the body and / or by devices to increase the surfaces in contact (grooves,

streaks, for example).

  Moreover, in the case of a metal belt ball, the crimping of the sleeve is effected in a manner

  known above the belt, while the self-

  crimp on the belt with a range of freedom on its positioning, and therefore on the dimensions

of the socket.

  The ball obtained is therefore perfectly

  producible and reliable ballistic characteristics.

  The balls may have various known shapes, such as conical, pointed, flats, with

shoulder of the ogival portion.

  FIG. 1 schematically represents the longitudinal section of a 5.56 caliber bullet whose body 1

  length of 14.5 mm has a pointed ogival end

  kills and whose belt 2 is positioned 3 mm from the base.

  This frustoconical inner section belt slightly flared upward with an opening angle of 3 degrees has for average thickness 1, 7 mm and for average height 6 mm. The body is made of a RILSAN brand name polyamide as defined above. The belt is made of a plastic material identical to that of the body, loaded with bronze balls of diameter between 0.01 and 0.1 mm and containing a solid lubricant consisting of bisulfide.

molybdenum. Its density and 4.

  The density of this bullet is 2.34.

  Figure 2 differs from Figure 1 by the geometry of the belt. This is also a frustoconical interior slightly flared upwards with an opening angle of 3 degrees, with an average thickness of 1.7 mm

but its height is 8.5 mm.

  The density of this bullet is 2.68.

  Bales may have other characteristics

  geometric and other compositions without departing from

of the invention.

  According to the manufacturing method of the invention, bi-injector presses are used provided with a multi-cavity rotary mold making it possible to mold, for example, 8 balls.

simultaneously.

  The overmolding of the body is done in masked time, by

  compared to the injection of the belt. Indeed, it is effec-

  killed while the injection of the belt is not completed.

  As a result, the manufacturing time is not the sum of

  durations of these two operations, but the duration of the longest

of these.

  In addition, industrial manufacture by two

  successive injection rations, without extracting the belt, - 6 -

  first part injected, makes it possible to overcome the difficulty

  the positioning of the belt encountered for

balls with metal belt.

  Finally, the amount of plastic material

  is substantially less (for example by a third) than that used for the manufacture of the ball

of the aforementioned FR-B-2,528,564 patent.

  The characteristics mentioned above allow

  to lower the cost of manufacturing compared to that of

  previous achievements for sufficient production.

-7-

Claims (9)

  A bullet for ammunition of reduced fire comprising a body made of plastic material of. low density and a higher density guide belt, characterized in that the   belt is made of plastic material loaded with   solid and containing particles of a lubricant.   2 - Ball according to claim 1, characterized in that the density of the belt is between 2 and 6 and, preferably, close to 4.   3 - Ball according to one of claims 1 or 2,   characterized in that the plastic material constituting the body has a density of about 1.   4 - Ball according to any one of the claims   1 to 3, characterized in that its overall density is included between 2 and 3.   5 - Ball according to any one of the claims   1 to 4, characterized in that the plastic material constitutes killing the body is a polyamide.   6 - Ball according to any one of the claims   1 to 5, characterized in that the plastic material of the belt is a polyamide.   7 - Ball according to any one of the claims   1 to 6, characterized in that the solid particles constitute   killing the load of the plastic material of the belt are in   metal, alloy or metal oxide.   8 - Ball according to claim 7, characterized in that the solid particles are constituted by bronze or lead oxide beads, of diameter between 0.01 and 0.1 mm.   9 - Ball according to any one of the claims   1 to 8, characterized in that the lubricant particles   contained in the plastic material of the belt are   formed by molybdenum disulfide.   - Method of manufacturing a bullet according to one   any of claims 1 to 9, implementing   presses biinjecter and characterized in that it comprises the following steps: 1) injection molding the plastic composition constituting the belt, then in the same cycle, 2) injection molding the body of the ball in   the space remains free, the belt being kept in fixed in the mold.