U.S. patent number 3,802,345 [Application Number 04/193,648] was granted by the patent office on 1974-04-09 for multiple projectile sabot assembly for use in rifled barrel.
This patent grant is currently assigned to AAI Corporation. Invention is credited to Nicholas Joseph La Costa.
United States Patent |
3,802,345 |
La Costa |
April 9, 1974 |
MULTIPLE PROJECTILE SABOT ASSEMBLY FOR USE IN RIFLED BARREL
Abstract
1. In combination with a rifled gun barrel having lands and
grooves in the bore, a sabot assembly comprising: A. a sabot
configuration including a sabot whose diameter is the same as the
diameter of said lands, a plurality of sub-caliber projectiles
contained in said sabot, and a pusher disc whose diameter is the
same as the diameter of said lands; B. said sabot and pusher disc
being slideably engaged with said lands and said pusher disc being
engaged with said sabot for pushing the same through said bore
under the influence of propellent gases therein; C. a deformable
obturator disc means having an anti-friction surface connection
with said sabot pusher disc and being interposed between the
propellant gases and said pusher disc; D. said obturator disc
having a nominal diameter that is the same as the diameter of said
grooves and being deformed by engagement with the lands and grooves
of said bore; and E. said obturator disc serving to push the
configuration through the bore and prevent propellent gases from
blowing past the configuration.
Inventors: |
La Costa; Nicholas Joseph
(Phoenix, MD) |
Assignee: |
AAI Corporation (Cockeysville,
MD)
|
Family
ID: |
22714455 |
Appl.
No.: |
04/193,648 |
Filed: |
May 2, 1962 |
Current U.S.
Class: |
42/78; 102/703;
102/522 |
Current CPC
Class: |
F42B
5/03 (20130101); F42B 12/64 (20130101); F42B
14/065 (20130101); Y10S 102/703 (20130101) |
Current International
Class: |
F42B
12/64 (20060101); F42B 12/02 (20060101); F42b
013/16 () |
Field of
Search: |
;102/93,94,95,38,91,49,42,63 ;89/1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Stahl; Robert F.
Attorney, Agent or Firm: Pippin, Jr.; Reginald F.
Claims
What is claimed is:
1. In combination with a rifled gun barrel having lands and grooves
in the bore, a sabot assembly comprising:
a. a sabot configuration including a sabot whose diameter is the
same as the diameter of said lands, a plurality of sub-caliber
projectiles contained in said sabot, and a pusher disc whose
diameter is the same as the diameter of said lands;
b. said sabot and pusher disc being slideably engaged with said
lands and said pusher disc being engaged with said sabot for
pushing the same through said bore under the influence of
propellent gases therein;
c. deformable obturator disc means having an anti-friction surface
connection with said sabot pusher disc and being interposed between
the propellent gases and said pusher disc;
d. said obturator disc having a nominal diameter that is the same
as the diameter of said grooves and being deformed by engagement
with the lands and grooves of said bore; and
e. said obturator disc serving to push the configuration through
the bore and prevent propellent gases from blowing past the
configuration.
2. The device of claim 1 wherein said pusher disc is metallic, and
including a polyfluorethylene surface connection at said interface
of said pusher disc and obturator disc whereby there is a low
coefficient of fricton between the two discs and spin imparted to
the obturator disc by said lands and grooves as it pushes said
configuration through said bore is not significantly transferred to
said configuration.
3. For use in a rifled gun barrel having lands and grooves in the
bore, a sabot assembly comprising:
a. a sabot configuration including a sabot whose diameter is the
same as the diameter of said lands, a plurality of sub-caliber
projectiles contained in said sabot, and a pusher disc whose
diameter is the same as the diameter of said lands;
b. said sabot and pusher disc being slideably engaged with said
lands and said pusher disc being engaged with said sabot for
pushing the same through said bore under the influence of
propellent gases therein;
c. a deformable obturator disc interposed between the propellent
gases and said pusher disc;
d. said obturator disc having a nominal diameter that is the same
as the diameter of said grooves and being deformed by engagement
with the lands and grooves of said bore;
e. said obturator disc serving to push the configuration through
the bore and prevent propellent gases from blowing past the
configuration;
f. the engagement of said obturator disc with said lands and
grooves imparting a spin to said obturator disc; and
g. said obturator disc being provided with means to reduce the
coefficient of friction between the obturator disc and the pusher
disc for minimizing the amount of spin imparted to said sabot
configuration when the latter is pushed through the bore by said
obturator disc.
4. The device of claim 3 wherein said obturator disc is rotatably
mounted on said pusher disc.
5. The device of claim 3 wherein said means to reduce the
coefficient of friction is the dissimilarity in materials between
the obturator disc and the pusher disc.
6. In combination with a rifled gun barrel having lands and grooves
in the bore, a sabot assembly comprising:
a. a sabot configuration including a sabot whose diameter is the
same as the diameter of said lands, and a plurality of sub-caliber
projectiles contained in said sabot;
b. said sabot being slideably engaged with said lands;
c. obturator means engaged with said lands and grooves and adapted
to be thrust and spun through the bore is response to propellent
gases therein; and
d. said obturator means being engaged with said sabot configuration
for transmitting thrust thereto without transmitting spin.
7. The device of claim 6 wherein said sabot configuration includes
a metallic pusher disc engaged with said obturator means, and the
material of said obturator means is Teflon.
Description
This invention relates to pusher-type sabots, and more particularly
to a pusher-type sabot configuration containing a cluster of
elongated subcaliber spin-stabilized projectiles.
A pusher-type sabot is one which has a portion interposed between
the propellent gases in a gun bore, and the sub-caliber projectile
means carried by the sabot. Such portions seals the propellent
gases in the bore and serves to push the projectile means
therethrough.
Under certain conditions, ammunition incorporating a sabot
configuration of the class described is more advantageous than
conventional ammunition. Optimum results would be achieved if it
were possible to easily switch a weapon from one type of ammunition
to the other to meet the exigency of a particular situation.
However, the weapon requirements for the two ammunitions are in
conflict because conventional ammunition requires a rifled barrel,
and previous to this invention, sabot ammunition incorporating a
cluster of sub-caliber projectiles required a smooth bore weapon.
Where a sabot includes an obturator portion to seal the propellent
gases and prevent them from blowing past the sabot, such portion
would be engageable with the grooves and lands of the rifling,
thereby causing the sabot to spin rapidly. A cluster of projectiles
contained in a spinning sabot would produce a dispersion pattern so
wide that ammunition of this type becomes ineffective. For this
reason, it is conventional to utilize a smooth bore weapon if the
dispersion pattern is to be as small as possible.
It is therefore an object of this invention to provide a sabot
assembly which can be used in a rifled barrel interchangeably with
conventional ammunition and which will produce a dispersion pattern
of the same order of magnitude as a sabot configuration launched
from a smooth bore weapon. As a feature of this invention whereby
the object thereof is achieved, the portion of the sabot assembly
housing the projectiles is made separate from the portion forming
the obturator seal so that the seal transmits thrust to the sabot
assembly but not spin.
Briefly, the invention includes a sabot configuration containing
the elongated sub-caliber projectiles which is the same diameter as
the lands of the rifling, and a deformable obturator disc of the
same diameter as the grooves. The coefficient of friction between
the obturator disc and the sabot configuration is made as low as
possible so that the disc transmits thrust to the sabot
configuration but not the spin imparted to the disc by the
rifling.
The more important features of this invention have thus been
outlined rather broadly in order that the detailed description
thereof that follows may be better understood, and in order that
the contribution to the art may be better appreciated. There are,
of course, additional features of the invention that will be
described hereinafter and which will also form the subject of the
claims appended hereto. Those skilled in the art will appreciate
that the conception upon which this disclosure is based may readily
be utilized as a basis for designing other structures for carrying
out the several purposes of this invention. It is important,
therefore, that the claims to be granted herein shall be of
sufficient breadth to prevent the appropriation of this invention
by those skilled in the art.
In the drawing:
FIG. 1 is a side view of a round of ammunition incorporating a
multiple projectile sabot assembly with parts broken away to better
illustrate the construction of the assembly.
FIG. 2 is a side section view of a multiple projectile sabot
assembly after the round is fired.
FIGS. 3 and 4 are sectional views taken along the lines 3--3 and
4--4, respectively, of FIG. 2.
FIG. 5 is a modification of the assembly shown in FIGS. 1 and
2.
Ammunition into which the present invention is incorporated is
shown generally at 10 in FIG. 1. Ammunition 10 includes casing 11,
powder charge 12 and sabot assembly 13. In outward appearance,
round 10 is the same as a conventional round.
Casing 11 includes base 14 and cylindrical side walls 15. Centrally
located in base 14 is primer 16 connected by port 17 to the
interior of the casing. Base 14 has extractor groove 18
therein.
Powder charge 12 is contained within the walls 15 between base 14
and assembly 13 which is inserted in the open end of the casing and
crimped thereto as at 19. Assembly 13 includes sabot configuration
20, and obturator disc 21. Configuration 20 includes segmented
sabot 22, pusher disc 23, and a plurality of elongated sub-caliber
spin-stabilized projectiles 24.
Sabot 22 is preferably made in quarters and when assembled is the
same diameter as the lands 25 in bore 26 of rifled barrel 27. Sabot
22 has coaxial hole 28 at the rear thereof that is somewhat larger
in diameter than the main coaxial hole 29 in the mid-portion of the
sabot so that fins 29' of projectiles 24 make a snug fit when
packed therein. Coaxial port 32 at the front of the sabot connects
separation bore 31 at the nose of the sabot to bore 29.
Pusher disc 23 of assembly 13 is preferably made from steel to
absorb projectile set back when the round is fired. Obturator disc
21 is preferably made from Teflon or the like so that there is a
low coefficient of friction between 21 and disc 23 of configuration
20. Furthermore, disc 21 is of the same diameter as the grooves 30
of the rifling of barrel 27, and has a tapered obturating flange 33
that extends circumferentially on the rear exposed face of the
disc. Disc 21 is deformable by lands 25 of the rifling when moved
axially in the bore so that the disc fills the bore completely and
prevents propellent gases from blowing past the configuration. The
deformation of flange 32 by the rifling serves to impart a spin to
disc 21 when the gases thrust it through the bore.
In operation, round 10 would be loaded into a weapon and fired in a
conventional manner by causing a firing pin(not shown) to strike
primer 16 causing ignition of charge 12. The resultant gases react
against disc 21 causing assembly 13 to be thrust into the rifling
of the barrel of the weapon. Disc 23 absorbs the projectile set
back. Configuration 20, being of the same diameter as lands 25,
merely slideably engages the latter and is not spun by the rifling
(see FIG. 3). Disc 21, on the other hand, being of the same
diameter as grooves 30, is deformed by the rifling and caused to
spin (see FIG. 4). The propellent gases react against flange 32,
pressing the latter into tight engagement with the bore of the
barrel and effectively sealing the gases against blowing past the
assembly. Because of the low coefficient of friction between the
disc 21 and disc 23, spin imparted to disc 21 by the rifling is not
imparted to configuration 20. Thus, disc 21 is effective to impart
a thrust to the donfiguration without imparting any spin.
Upon muzzle exit, air enters orifice 31 and the pressure strips the
sabot from the cluster 24' of projectiles 24. Such cluster, because
it has not been spun up by the rifling, has substantially the same
dispersion characteristics as a cluster launched from a smooth-bore
weapon.
While FIGS. 1 and 2 illustrate a Teflon-metal combination for discs
21 and 23, other combinations have proven to be successful. For
example, a lubricant, such as molybdenum disulfide can be used to
advantage between a metal-to-metal combination; or, small ball
bearings or Teflon discs could be inserted between the discs
whereby they act as a miniature thrust bearing. Whether the
combination is Teflon-metal, or metal-to-metal with a lubricant or
ball bearings therebetween, the obturator disc may properly be
described as being provided with means for reducing the coefficient
of friction between the obturator disc and the sabot
configuration.
In order to prevent the pusher disc from impacting lands 25, the
modification of FIG. 5 can be used. Here, configuration 20'
includes segmented sabot 22 containing a cluster of sub-caliber
projectiles and pusher disc 23'. Centered in the rear surface of
disc 23' is circular recess 40 into which boss 41, centrally
located on the front of obturator disc 21', rotatably fits. The
engagement of boss 41 in recess 40 prevents radial shifting or
balloting of disc 23', and so prevents the edges of the disc from
impacting lands 25. The remaining operation is the same as
previously described.
* * * * *