U.S. patent number 3,722,411 [Application Number 05/100,043] was granted by the patent office on 1973-03-27 for plastic shotshell with sealing rings.
Invention is credited to George L. Herter.
United States Patent |
3,722,411 |
Herter |
March 27, 1973 |
PLASTIC SHOTSHELL WITH SEALING RINGS
Abstract
A plastic shotshell case to be loaded with powder and shot
charges and wads separating the shot and powder; the plastic case
having peripheral ribs or rings at the exterior adjacent the open
mouth of the case and effectively sealing the case wall against the
shotshell chamber in the barrel of the shotgun; the exterior
peripheral surface of the case wall being smooth at a location
forwardly of the sealing ribs.
Inventors: |
Herter; George L. (Waseca,
MN) |
Family
ID: |
22277837 |
Appl.
No.: |
05/100,043 |
Filed: |
December 21, 1970 |
Current U.S.
Class: |
102/466 |
Current CPC
Class: |
F42B
5/30 (20130101) |
Current International
Class: |
F42B
5/00 (20060101); F42B 5/30 (20060101); F42b
005/30 () |
Field of
Search: |
;102/43R,43P,42,38,44 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Stahl; Robert F.
Claims
What is claimed is:
1. A shotshell case comprising,
a tubular case wall constructed of plastic, the case wall having a
front closure end from which the shot charge exits upon ignition of
the powder charge,
and a plurality of external circumferential ribs on the case wall
and formed integrally thereof adjacent the closure end, said ribs
having a thickness in a radial direction several times less than
the thickness of the case wall, said ribs being engageable with the
barrel wall to seal against the barrel and prevent gases under
pressure from escaping along the case wall and toward the breech
bolt of the shotgun only upon firing the shotshell and ignition of
the powder therein.
2. The shotshell case according to claim 1 and said ribs having a
width in a direction along the case wall on the same order as the
thickness of the case wall.
3. The shotshell case according to claim 2 and said ribs being
spaced from each other by a distance of the same order as the width
of the shells.
4. The shotshell case according to claim 1 and said case wall being
constructed of plastic consisting to a large degree of
polycarbonate.
5. The shotshell case according to claim 1 and said case wall being
constructed of plastic consisting to a large degree of
polyethylene.
6. The shotshell case according to claim 1 and the case wall
extending toward the front well beyond the circumferential ribs and
sufficiently to produce a closure by a star crimp.
7. The shotshell case according to claim 1 and the case wall
terminating immediately forwardly of the ribs to receive and retain
an end wad to effect the closure.
8. The shotshell case according to claim 6 and the exterior surface
of the case wall at locations forwardly of and rearwardly of the
ribs being respectively smooth and striated in a longitudinal
direction.
Description
BRIEF SUMMARY OF THE INVENTION
The plastic shotshell case with a plurality of outwardly projecting
rings or ribs extending peripherally of the case adjacent the open
mouth or closure end of the case that function principally at the
instant of firing, at which time the rapidly burning powder gases
are expanding and creating extremely high gas pressures within the
shotshell case and the shotgun barrel. At this instant, the gas
pressure forces the case wall outwardly and causes the rings to
engage and seal against the barrel wall to prevent gas from
escaping in a rearward direction along the exterior surface of the
case and adjacent the breech bolt of the shotgun.
The plastic shotshell case is formed by injection molding of
plastic; and may be formed principally of polyethylene plastic; or
it may be desired to form the shotshell case principally of a
polycarbonate plastic.
The exterior peripheral surface of the shotshell case wall is
striated in a longitudinal direction throughout a major portion of
the length of the shotshell case wall; and at locations forwardly
of the rings, the polyethylene case wall has its exterior
peripheral surface smooth and unbroken for a distance of
approximately half the diameter of the tubular shotshell case for
forming the star crimp closure of a shotgun shell after the shell
is loaded with the shot, powder and wads. The smooth exterior
peripheral surface at this portion of the shotshell prevents or
minimizes through numerous loadings and reloadings of the shotshell
case, splitting of the case due to repeated folding in the numerous
reloads and formations of the star crimp for enclosing the interior
of the shotshell case.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an enlarged elevation view of the plastic shotshell
case.
FIG. 2 is a greatly enlarged detail section view taken
approximately at 2--2 in FIG. 1 and showing the relative size
relationship between the ribs or rings and the case wall and the
relationship between the several ribs along the case wall.
FIG. 3 is an elevation view at a reduced scale of the shotshell
which is partly broken away for clarity of detail and shown applied
into the shotshell chamber of the barrel of a shotgun and retained
by the breech bolt, the details of the breech construction of the
shotgun barrel are mostly eliminated.
FIG. 4 is an elevation view of a modified form of plastic shotshell
case wherein the closure is formed by a top wad.
DETAILED DESCRIPTION OF THE INVENTION
The plastic shotshell case is indicated in general by numeral 10
and is formed by injection molding. The shotshell case is
integrally formed in one piece, and the entire shotshell case is
formed in one molding process so that the entire case is integral
and all portions of it are of the same material. The shotshell case
may be formed of polyethylene plastic, and may have small
quantities of other types of plastics mixed in with the
polyethylene to obtain certain strength and other characteristics.
Likewise, it may be desirable to form the all plastic shotshell
case 10 of a polycarbonate plastic, either a pure polycarbonate or
possibly with other plastics mixed in to give the plastic certain
characteristics. It will be understood that polycarbonate plastic
is very hard and withstands high impact, and has been successfully
used in the production of such shotshell cases, which are
subsequently made into shotgun shells for hunting and other types
of shooting.
The shotshell case 10 has a base portion 11 and an ejecting flange
12, and an elongate tubular case wall 13 terminating at its front
end 14 in an open mouth through which the ejectable components of
the shotshell, including the shot charge, powder charge, the wads,
etc., are loaded into the shotshell case for forming the shotshell.
Of course, the case is closed at the base 11 and a primer is
mounted in the base for ignition of the powder charge upon firing
the shotshell in a shotgun. Along a major portion of the case wall
13, the exterior peripheral surface of the case wall is striated as
indicated at 15. The striate texture of the exterior peripheral
surface contributes to ease and comfort of handling the shotshell
case and the shotshells which are eventually made therefrom, and to
give the shotshell case a pleasing appearance.
The forward portion 16 of the tubular case wall 13 is smooth at its
exterior peripheral surface for a distance along the length of the
case from the open mouth equaling approximately half the diameter
to facilitate the formation of a star crimp in the smooth surfaced
front end portion 16. It will be understood that in the formation
of a star crimp the front portion 16 of the case wall is folded
numerous times in an accordian pleat type shape around the
periphery of the case wall so that upon forming the star crimp and
upon the repeated formations of star crimps and the opening of the
crimps under force of the shot and gas pressures in the shotshell
case, there is some tendency for the case wall to split because of
the folding. However, the smooth exterior peripheral surface of the
portion 16 of the case wall adjacent the open mouth where the star
crimp is formed tends to minimize the likelihood of there being any
splitting of the shotshell case in spite of numerous reloadings of
the polyethylene shotshell case. It has been found that a shotshell
case such as that disclosed herein may be reloaded eight to ten
times without splitting the shotshell case in the vicinity of the
front end portion 16 even though the star crimps are formed a like
number of times.
At the exterior peripheral surface of the case wall 13, the
portions 15 and 16 are separated by a plurality of outwardly
projecting cylindrical rings or ribs 17 on the exterior periphery
of the case wall. The ribs or rings 17 project only a very small
distance from the peripheral face of the case wall, so that these
ribs 17 will not interfere with the normal handling and usage of
the shotshell case during loading of the case and during insertion
of the loaded shotshell into the barrel 20 of a shotgun or the
removal of the expended or emptied case from the barrel. The ribs
17 have a thickness or height in a radial direction only
approximately one-tenth the thickness of the case wall. The width
of each of the ribs 17, in a direction longitudinally of the case
wall, is of the same order as the thickness of the case wall in the
vicinity of these ribs. The spacing between the ribs 17 is of the
same order of dimensions as the width of these ribs. It is
preferable that the forwardmost rib 17 is disposed a sufficient
distance from the open mouth end 14 of the shotshell case so that
the entire star crimp can be formed in the end portion 16 of the
case wall without distorting the forwardmost rib 17.
When the shotshell case is properly loaded with powder, wads, shot,
and the case is closed for firing, the loaded shotshell 19 may be
inserted into the shotshell chamber of the shotgun barrel and be
retained therein by the breech bolt 21 in a well known manner. The
firing of the shotshell causes instant ignition of the powder in
the shotshell case and development of high gas pressures due to the
combustion and expansion of the powder gases as the shot charge is
suddenly set into motion along the gun barrel and toward the muzzle
end. As the gas pressures in the shotshell case build up, the
shotshell case wall 13 expands very slightly against the interior
surface of the shotshell chamber of the barrel 20 and the ribs 17
produce a highly efficient seal between the shotshell case 13 and
the barrel 20 so as to prevent powder gases, or other materials
such as unburned powder, from escaping in a direction rearwardly
along the case wall 13. and toward the breech bolt 21. The seal
produced by the ribs 17 bearing against the barrel effectively
prevents the loss of gas pressure in a reverse direction and, as a
result, all of the gas is effectively utilized for acceleration and
propulsion of the shot charge toward the muzzle of the barrel.
In the form of shotshell 25 illustrated in FIG. 4, the shotshell
case 26 has a plurality of sealing ribs 17' identical to those
illustrated in FIGS. 1 - 3. In this form of the shotshell case 26,
the case wall 13' terminates just forwardly of the forwardmost rib
17', as indicated at 14', and this forward edge of the shotshell
case wall 13' is simply rolled over slightly to retain the end wad
or closure wad 27 applied within the periphery of the case wall and
over the shot confined in the shotshell 25.
As previously described in connection with FIGS. 1 - 3, the ribs 17
serve to seal the case wall 13' against the shotgun barrel to
prevent high pressure gases from traveling or leaking rearwardly
along the shotshell case upon ignition.
It will be seen that I have provided a new and improved all plastic
shotshell case with sealing ribs extending peripherally adjacent
the mouth end of the case wall to seal against the shotshell
chamber of the shotgun barrel upon firing of the shotshell when
high pressures are developed through expansion of powder gases. The
plastic shotshell case also has a smooth and unbroken exterior
peripheral surface in the forward portion of the case wall which is
utilized for the star crimp so as to contribute to the continued
life of the shotshell case through numerous reloadings without
splitting at the forward star crimp portion of the shotshell
case.
* * * * *