PLASTIC CARTRIDGE CASE AND DEVICE FOR THE PRODUCTION THEREOF

DOUILLE DE CARTOUCHE EN PLASTIQUE ET DISPOSITIF SERVANT A SA FABRICATION

English Abstract

The present invention generally relates to small arms technology and, more
particularly, is
concerned with hunting and sporting cartridges having plastic cases.
The objective of the invention is increasing of the ballistic data and
structural strength of the
product with low price of its manufacturing.
This problem is solved by supplying of the plastic cartridge case in the shape
of thin-walled
cup of cylindrical external surface and internal surface comprising three
conical portions of
length and taper increasing from the bottom having the opening for the primer
with a
dam-diaphragm separating the cartridge case part and the part for the primer
installation. The
dam-diaphragm thickness is selected within the range of 0,2 - 0,5 mm.
The device for manufacturing of the plastic cartridge case contains a mold
performed of a
matrix forming the external surface of the cartridge case, a halfmatrix with
conical casting
opening which forms the cup bottom and a punch forming the internal surface of
the cartridge
case. On the halfmatrix is a cylindrical hollow pin forming a closed primer
opening. The
cylindrical hollow pin together with the punch form a ring spree.

French Abstract

Cette invention se rapporte au domaine de l'armement et concerne des douilles de cartouches en plastique utilisées pour la chasse et le sport. Cette invention vise à améliorer les propriétés balistiques et la résistance de l'article ainsi qu'à réduire son coût de fabrication. La douille de cartouche en plastique de la présente invention se présente sous la forme d'un cylindre à parois minces pourvu d'une paroi cylindrique externe et d'une paroi interne définissant trois parties coniques dont l'étendue et la conicité augmentent lorsqu'on s'éloigne du fond du cylindre. Le fond du cylindre comporte un orifice d'amorce de mise à feu. Cette douille de cartouche en plastique comprend également une cloison à paroi mince qui sépare la cavité du cylindre de la cavité de l'amorce de mise à feu. L'épaisseur de la cloison-diaphragme est comprise entre environ 0,2 et 0,5 mm. Le dispositif servant à fabriquer cette douille de cartouche en plastique comprend un moule en forme de matrice définissant la surface externe de la douille, une demi-matrice pourvue d'un orifice de remplissage conique et formant le fond du cylindre, et un poinçon, définissant la surface interne de la douille. Cette demi-matrice est pourvue d'un doigt cylindrique creux définissant un orifice d'amorce de mise à feu borgne et formant conjointement avec le poinçon une buse annulaire d'injection.

Claims

3
Claims
1. The plastic cartridge case, performed in the shape of thin-walled cup of
cylindrical
external surface and internal surface performed of three conical portions of
length and
taper increasing from the bottom with the opening for the primer, is notable
for the
dam-diaphragm of 0,2 - 0,5 thickness separating the cartridge case part and
the part
for the primer installation.
2. The device for the plastic cartridge case manufacturing, contained the mold
performed
of the matrix forming the external surface of the cartridge case, the
halfmatrix with
conical casting opening which forms the cup bottom and the punch forming the
internal surface of cartridge case, is notable for carried out on the
halfmatrix hollow
pin, forming the closed primer opening and, together with the punch forming
the ring
sprue.

Description

CA 02417847 2003-O1-29
Plastic cartridge case and device for the production thereof
The present invention generally relates to small arms technology and, more
particularly, is
concerned with hunting and sporting cartridges with plastic cases.
There are known plastic cases for sporting and hunting cartridges in the shape
of thin-walled
cup of cylindrical external surface and with opening at the bottom for primer
(Patent UK
1161422, F 42B 5/30, published in 1969).
Known from this source device for manufacturing of plastic cartridge case
composes of a
mold and a distribution block with casting openings.
The main drawback of the existing case is its low structural strength - the
case breaks down
during shooting. Internal surface geometry of the case and its processing
technique do not
provide structural strength because of casting defects.
These defects are not peculiar to the existing plastic cartridge case with
internal surface
comprising three conical portions of length and taper increasing from the
bottom (Certificate
for useful model RU 11882, F 42 B 5/30, 1999 - closest analog). The device for
manufacturing of the case is described in this source.
The drawback of the existing case is penetration of powder corpuscles into the
primer during
the filling of the cartridge resulting in failure of ignition and cartridge
parameters spread.
The drawback of the device for manufacturing of the case is that the
cylindrical pin is
arranged on the punch what leads to declination from axis during the casting
of matrix by
working mass resulting in the case geometry failure and reduction of
structural strength.
The objective of the invention is increasing of the ballistic data and
structural strength of the
product with low price of its manufacturing.
This problem is solved by additional supplying of the plastic cartridge case
in the shape of
thin-walled cup of cylindrical external surface and internal surface
comprising three conical
portions of length and taper increasing from the bottom having the opening for
the primer
with a dam-diaphragm separating the cartridge case part and the part for the
primer
installation. The dam-diaphragm thickness is selected within the range of 0,2 -
0,5 mm.
The device for manufacturing of the plastic cartridge case contains a mold
performed of a
matrix forming the external surface of the cartridge case, a halfmatrix with a
conical casting
opening which forms the cup bottom and a punch forming the internal surface of
the cartridge
case. On the halfmatrix is a cylindrical hollow pin forming a closed primer
opening. The
cylindrical hollow pin together with punch form a ring sprue.

2
CA 02417847 2003-O1-29
w 4 The longitudinal section of the cartridge case is shown on picture l and
section of the device
for manufacturing of the plastic cartridge case is shown on picture 2.
The cartridge case is shaped as the cup 1 with internal surface 2 comprising
three conical
portions.
At the bottom 3 is the primer opening 4. Inside of the cup (around the opening
4) there is a
compensation groove 5.. A recess 6 performed concentrically with the opening 4
on the
outside surface of the bottom 3.
The cup (cartridge case) part and part for the primer installation is divided
by the dam-
diaphragm 7.
The device for manufacturing of the plastic cartridge case consists of the
matrix 8, the
halfmatrix 9 and the punch 10. Made on the halfmatrix the cylindrical hollow
pin 11 forms
the closed primer opening. The ring sprue 12 is between the surface of the pin
1 l and the
surface of the punch 10.
The manufacturing process of the cartridge case is as follows:
The plastic mass is supplied from the distribution block (not shown on the
picture) into the
cylindrical opening of the halfmatrix 9, then through the pin 11 and the ring
spxue 12
penetrates into the mold filling full its space uniformly excluding appearance
of defects.
After taking the finished cartridge case out of the mold, unnecessary part of
pour is removed
leaving the dam between the parts of the cartridge case.
The cartridge case manufactured according to this method has the following
advantages.
The cartridge case has improved structural strength characteristics. Division
of the cartridge
case parts: the primer part and the combustion part results in improvement of
ballistic
characteristics of the cartridge case due to exclusion of powder charge effect
on burning
intensity of the primer and ignition process improvement.
Proceeding from the tests the thickness of the dam-diaphragm should be
selected within the
range. of 0,2 - 0,5 mm. The described cartridge case has improved structural
strength
characteristics, low manufacturing price, shorter range of spread of filled
cartridge parameters
of powder charge pressure and shot speed.

Representative Drawing