U.S. patent number 3,808,974 [Application Number 05/196,627] was granted by the patent office on 1974-05-07 for all plastic shotshell case with transversely oriented undulations on outer cylindrical surface.
This patent grant is currently assigned to Herter's Inc.. Invention is credited to George L. Herter.
United States Patent |
3,808,974 |
Herter |
May 7, 1974 |
ALL PLASTIC SHOTSHELL CASE WITH TRANSVERSELY ORIENTED UNDULATIONS
ON OUTER CYLINDRICAL SURFACE
Abstract
An all plastic shotshell case molded with the transverse base
wall and cylindrical sidewall integral of and in one piece with
each other, and the outer surface of the cylindrical sidewall
having undulations all along the length thereof and oriented
transversely of the longitudinal orientation of the cylindrical
sidewall, said transverse undulations forming rings extending
circumferentially around the cylindrical sidewall, or said
undulations being in the pattern of circles, dots, squares, knurls
or other shapes.
Inventors: |
Herter; George L. (Waseca,
MN) |
Assignee: |
Herter's Inc. (Waseca,
MN)
|
Family
ID: |
22726175 |
Appl.
No.: |
05/196,627 |
Filed: |
November 8, 1971 |
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
007/06 () |
Field of
Search: |
;102/42R,43R,43P |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,448,965 |
|
Aug 1966 |
|
FR |
|
1,114,134 |
|
May 1968 |
|
GB |
|
Primary Examiner: Bentley; Stephen C.
Attorney, Agent or Firm: Williamson, Bains & Moore
Claims
1. An all plastic shotshell case comprising:
a substantially cylindrical sidewall of molded plastic open at one
end;
a base wall of molded plastic extending transversely of said
sidewall at the opposite end thereof, said sidewall and base wall
being formed integrally as one piece, and said base wall having an
opening therein to receive the primer of the shotshell; and
a plurality of undulations on the outer surface of said sidewall
projecting outwardly therefrom, said undulations being formed
integrally with said sidewall and extending in longitudinally
spaced circular patterns over more than one half of the length of
said sidewall up to and along said open end thereof, and said
undulations being in the form of circumferentially extending rings
of varying width in a direction along the length of said
cylindrical sidewall, with the narrower rings being disposed
adjacent said open end of said sidewall and being deformable
against a shotgun barrel under the pressure developed within
said
2. An all plastic shotshell as defined in claim 1 wherein:
said undulations comprise a plurality of closely clustered annuli
of
3. An all plastic shotshell comprising:
a substantially cylindrical sidewall of molded plastic open at one
end;
a base wall of molded plastic extending transversely of said
sidewall at the opposite end thereof, said sidewall and base wall
being formed integrally as one piece, and said base wall having an
opening therein to receive the primer of the shotshell; and
a plurality of undulations on the outer surface of said sidewall
projecting outwardly therefrom, said undulations extending
transversely with respect to said cylindrical sidewall in generally
circular patterns over a substantial portion of the length of said
sidewall up to and along said open end thereof, and said
undulations being of varying width in a direction along the length
of said sidewall with the narrowest undulations being disposed
adjacent said open end of said sidewall.
Description
BRIEF SUMMARY OF THE INVENTION
It has been found that all plastic shotshell cases wherein the
transverse base wall and the cylindrical sidewall are integral of
and in one piece with each other and are molded of any of a number
of types of plastic such as linear polyethylene, will have more
strength where the outer surface of the cylindrical sidewall is
provided with a plurality of shallow undulations throughout the
entire length of the cylindrical sidewall. Such undulations may be
arranged in any of a number of patterns on the outer surface of the
sidewall, and it has been found advantageous to arrange such
undulations so that rings are formed extending circumferentially
around the entire periphery of the cylindrical sidewalls, and all
along the length of the sidewall case. The result is to strengthen
the walls of the case, and this is caused, at least in part,
because during the filling of the mold in which the shotshell case
is formed, the plastic is flowed into the mold cavity in a
direction longitudinally of the cylindrical sidewall being formed,
and therefore across the undulations in the mold part forming the
outer surface of the cylindrical sidewall. The molten plastic,
during filling of the mold cavity, flows across these undulations
in the mold part and causes some degree of laminating of the
plastic during the flow which results in the increased strength of
the plastic after the plastic is allowed to cure and harden.
It has been found that the undulations, oriented transversely of
the longitudinal orientation of the cylindrical sidewall may be
arranged in various patterns such as the rings extending
circumferentially of the cylindrical sidewall, but the pattern may
take the form of circles, dots, squares, knurls or any other
convenient shape which nests together into an overlapping relation
and which have at least a portion thereof extending transversely of
the longitudinal orientation of the cylindrical sidewall.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is an enlarged elevation view, partly broken away, and in
section, and illustrating a shotshell case according to the present
invention, and illustrating the open mouth of the case closed with
the usual star crimp.
FIG. 2 is a greatly enlarged longitudinal section view taken
approximately at 2--2 in FIG. 1.
FIG. 3 is a fragmented detail view showing a small portion of the
mold parts used in molding the all plastic shotshell case
illustrated in FIGS. 1 and 2 to carry out the invention.
FIG. 4 is a greatly enlarged detail elevation view of the outer
surface of a cylindrical shotshell sidewall, and illustrating a
modified form of the invention.
FIG. 5 is a view similar to FIG. 4 and illustrating a second
modified form of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The all plastic shotshell case is indicated in general by numeral
10 and includes a transversely oriented base wall 11 and an
elongate, substantially cylindrical sidewall 12. The base wall 11
and the sidewall 12 are molded integrally of and in one piece with
respect to each other, and are formed of any of a number of
plastics suitable for molding all plastic shotshell cases, such as
linear polyethylene, or an extrusion grade polyethylene material
which is somewhat stiffer in consistency when injected into the
mold cavity than other polyethylenes. The base wall of the
shotshell case has an opening 13 therein to receive the primer of
the shotshell, and the shotshell case has an open interior 14 for
receiving the usual powder charge, wadding, and shot charge which,
when added to the case and primer, make up the loaded shotshell. In
the drawings, the integral closure 15 is shown in the position of a
star crimp for illustration purposes, even though no powder or shot
charge is contained in the shotshell.
The substantially cylindrical sidewall 12 is provided with a series
of undulations 16a and 16b which are actually grooves and ribs or
ridges respectively, extending circumferentially around the entire
periphery of the substantially cylindrical wall 12. It is pointed
out that the undulations 16a and 16b are provided on the outer
surface of the sidewall, throughout substantially the entire length
of the sidewall, and substantially strengthen the case
sidewall.
It will be noted that the spacing between undulations may be varied
at various locations along the length of the case sidewall, and in
this form illustrated, the undulations 16a' and 16b' are smaller
than the spacings between undulations along other portions of the
case sidewall. The ribs and grooves formed by the undulations 16a'
and 16b' form a more efficient sealing relationship with the
chamber of the shotgun barrel when the case is fired, due to the
extreme magnitude of gas pressure that builds up at the inner
chamber 14 of the shotshell case upon firing of the shotshell and
deformation of the plastic against the barrel wall at the
rib-forming undulations 16b'.
FIG. 3 illustrates the molding of the shotshell case sidewall and
shows a fragmented portion of the mold assembly which includes the
mold part 20 which cooperates with the core 21 to define the mold
cavity 22 therebetween. The mold cavity is correspondingly
substantially cylindrically shaped to conform to the shape of the
substantially cylindrical sidewall 12, and of course, the mold
cavity 22 also extends across the end of the core to shape the
plastic which forms the base wall 11 of the shotshell case. The
mold part 20 has undulations 20a and 20b in its surface which form
the outer surface of the substantially cylindrical sidewall 12. As
illustrated, the molten plastic 23 is flowed in a direction
longitudinally along the core 21 and longitudinally of the
substantially cylindrical mold cavity 22, as indicated by the
direction of arrow A. Because of this flow of the plastic material,
the transversely oriented undulations 20a and 20b are encountered
as the plastic flows in the direction of arrow A and because of the
drag or restriction to flow at the undulations 20a, 20b, there is
laminating of the plastic during the flow and a resultant
strengthening of the case sidewall after the case is allowed to
cure and harden. Of course, because of the undulations, the
plastic, as it flows, has a shear location 23.1 as indicated by the
dotted lines in FIG. 3, outwardly of which the plastic is retarded
in movement and inwardly of which the plastic flows with full
velocity in the direction of arrow A.
The resulting all plastic shotshell case 10 has an increased
strength in the substantially cylindrical sidewall 12 due to the
presence of the undulations and rings around the periphery
thereof.
In the form illustrated in FIG. 4, the outer surface of the
sidewall 12.1 is provided with a plurality of undulations 12.1a and
12.1b forming patterns on the outer surface of the sidewall in the
form of a plurality of clustered circular annuli having a height
similar to that of the undulations 16a and 16b illustrated in FIG.
1 wherein these undulations have a magnitude in a direction
transversely of the case sidewall which is considerably less than
the thickness of the sidewall. It will be noted that the circular
annuli formed by the undulations 12.1a and 12.1b have portions
oriented transversely of the elongate substantially cylindrical
sidewall case 12.1
In FIG. 5 another form of the invention is illustrated wherein the
substantially cylindrical sidewall 12.2 is provided with a
plurality of undulations 12.2a and 12.2b arranged in a pattern
forming closely nested squares or rectangles. It will be noted that
portions of the undulations 12.2a and 12.2b are oriented
transversely of the longitudinal orientation of the substantially
cylindrical sidewall.
It should be understood that the undulations on the outer surface
of the sidewall may be arranged in other patterns including dots,
diamonds, knurls, or any of the other common geometric shapes,
which have a portion oriented transversely or at least obliquely
transversely of the longitudinal orientation of the sidewall
case.
It will be seen that I have provided a new and improved all plastic
shotshell case wherein the outer surface of the substantially
cylindrical sidewall is provided with undulations arranged in a
pattern with portions extending transversely of the elongate
longitudinal orientation of the substantially cylindrical sidewall
effecting a strengthening of the sidewall against outward expansion
and rupture due to pressure developed within the case.
* * * * *