FLEXIBLE PRESSURE VESSEL FOR ASSEMBLED AMMUNITION CASING
An ammunition case includes an elongate interior cavity for receiving a propellant and a projectile and extending along a longitudinal axis between a top end and a bottom end, and a bottom corner of the cavity having a reversed radius design supported by a shaped base.
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This application claims benefit from U.S. Provisional Patent Application Ser. No. 62/500,786, filed May 3, 2017, and U.S. Provisional Patent Application Ser. No. 62/553,578, filed Sep. 1, 2017, both of which are incorporated by reference in their entireties.
STATEMENT REGARDING GOVERNMENT INTERESTNone.
BACKGROUND OF THE INVENTIONThe present invention relates to ammunition articles, and more particularly to a flexible pressure vessel for an assembled ammunition casing.
Firearm ammunition cartridges typically include a casing holding the projectile or bullet, a propellant, such as gunpowder or cordite, and an igniting means including a primer or igniting medium. Thus, the casing is used as a container for functionally holding together and arranging the other cartridge components. In general, because of the extreme nature of the application, materials used for fabrication of ammunition cartridges must demonstrate excellent mechanical properties. Ammunition for civilian and military use has been built using single piece brass casings for one hundred fifty years. Other materials such as aluminum and steel have also been used in efforts to reduce price or has alternate supply when the copper supply becomes tight. However, very little effort has gone into casing improvement over the years.
It has been desirable in the cartridge design to improve the pressure withstanding capability of the casing. Recent developments in two piece casings have brought promise. A casing is already marketed having a stainless pressure vessel mated to an aluminum alloy base. However, one of the limiting factors is increased pressure is the ability of the bottom corner of the pressure vessel to withstand the desired higher pressures. The lower corner of the tube is the weakest part of the design.
What is needed is an improvement apparatus to overcome these and other shortcomings.
SUMMARY OF THE INVENTIONThe following presents a simplified summary of the innovation in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is intended to neither identify key or critical elements of the invention nor delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.
In general, in one aspect, the invention features an ammunition case including an elongate interior cavity for receiving a propellant and a projectile and extending along a longitudinal axis between a top end and a bottom end, and a bottom corner of the cavity having a reversed radius design supported by a shaped base.
In another aspect, the invention features an ammunition case including an elongate interior cavity for receiving a propellant and a projectile and extending along a longitudinal axis between a top end and a bottom end, and a bottom corner of the cavity having a broad radius design supported by a shaped base.
In still another aspect, the invention features an ammunition case including an elongate interior cavity for receiving a propellant and a projectile and extending along a longitudinal axis between a top end and a bottom end, and a bottom corner of the cavity having an angle/radius combination supported by a shaped base.
In another aspect, the invention features an ammunition case including a case, the case having a wall deformed in a pattern of deformations directed inwardly, enabling a balance of outer profile maintenance for general loading and handling while giving spring characteristics of in an axial direction.
In another aspect, the invention features an ammunition case including an elongate interior cavity for receiving a propellant and a projectile and extending along a longitudinal axis between a top end and a bottom end, and having one or more grooves rolled into the sidewall above a bottom corner.
These and other features and advantages will be apparent from a reading of the following detailed description and a review of the associated drawings. It is to be understood that both the foregoing general description and the following detailed description are explanatory only and are not restrictive of aspects as claimed.
These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings where:
The subject innovation is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It may be evident, however, that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the present invention.
As shown in
The sidewall 3, which is an elongate tubular portion, includes in longitudinal direction sections 6a and 6b having different diameters and a corresponding transition region 6c between the lower, larger diameter section 6b and the upper, smaller diameter section 6a. The sections 6a and 6b may or may not be slightly tapered in the longitudinal direction, in particular in a direction away from the bottom wall 2.
The bottom wall 2 includes a through bore 7 which extends in a longitudinal direction and has a lower, large diameter section 7a extending from a lower axial end surface 8 of the bottom wall 2 and an upper, small diameter section 7b.
The casing 1 is composed of two separate elements or components, namely an elongate tubular sleeve component 10 and a bottom component 11, which are mechanically secured to each other. The sleeve component 10 is not identical with the elongate tubular portion forming the sidewall 3, but that the sleeve component 10 also forms a relatively small portion of the bottom wall 2. Consequently, while the bottom component 11 forms nearly all of the bottom wall 2, it does not form the entire bottom wall 2.
The material from which the sleeve component 10 is constructed is of a considerably lower thickness than the material from which the bottom component 11 is constructed. Thus, the thickness of the sleeve component 10 throughout its entire extension is smaller than the thickness of the entire bottom component 11, with the exception of a portion 16. In particular, the thickness contribution provided by the bottom component 11 to the total thickness of the bottom wall 2 in the longitudinal direction is considerably larger than the material thickness anywhere in the sleeve component 10.
For allowing a simple mechanical attachment of the bottom component 11 to the sleeve component 10, the sleeve component 10 is formed such that at its lower end 12 it includes a radially inwardly projecting annular flange 13, the lower surface 14 of which constitutes an annular lower axial end surface or bottom surface of the sleeve component 10. The surface 14 is the lowermost portion of the sleeve component 10, i.e. the lower terminal axial end thereof. This bottom surface 14 of the sleeve component 10 is arranged in abutment with a corresponding annular upper axial end surface 15 of the bottom component 11 and may be attached thereto by suitable means.
The attachment is effected by the annular bent-back portion 16 of the bottom component 11, which extends in parallel to and at a certain axial distance from the annular upper axial end surface 15 of the bottom component 11 in the immediate vicinity of the through bore 7. The annular flange 13 of the sleeve component 10 is arranged to extend into the annular space defined by the end surface 15 and the bent-back portion 16 of the bottom component 11, and the sleeve component 10 is thereby locked in place and securely retained on the bottom component 11 in the position illustrated. Due to the mating construction of the annular bent-back portion 16 of the bottom component 11 and of the annular flange 13 of the sleeve component 10, the sleeve component 10 and the bottom component 11 are self-centering upon assembly.
The bottom component 11 has the shape of a planar ring. In the longitudinal direction it includes two adjacent sections 17a, 17b having different diameters and forming a sharp rectangular step 19 between them. Thus, the bottom component 11 includes a lowermost annular projection 18 radially outwardly projecting as compared to the recessed portion 17b and actually the entire remainder of the bottom component 11. A lower end 12 of the sleeve component 10 and, consequently, the peripheral outer edge 20 of the annular flange 13 of the sleeve component 10 has a diameter which is larger than the diameter of the recessed portion 17b of the bottom component 11 and is identical or substantially identical to the diameter of the annular projection 18 of the bottom component 11. Due to this construction, an annular groove 21 is present in the radial outer surface of the bottom component 11, wherein the borders or sidewalls of this groove 21 are formed by the two steps 19 and 20. In the assembled cartridge the groove 21 serves as the extractor groove for extracting the empty casing 1 from the firing chamber of the firearm following actuation thereof.
It is also possible for the section 17b to have the same or essentially the same radial diameter than the or a lower end 12 of the sleeve component 10 and, consequently, the peripheral outer edge 20 of the annular flange 13 of the sleeve component 10. In such a case, the cartridge casing 1 does not include an extractor groove, but the annular projection 18 at the very bottom of the bottom component 11 and the step between the projection 18 and the recessed portion 17b is provided for engagement by an extraction mechanism.
As can be seen in
The problem is made worse by a design that requires an internal corner radius of less than the material thickness. Forming this radius necessarily reduces the cross sectional thickness in the are of the radius further reducing the load carrying capability. Thus, the sharp corner 102 is the area where the motion of the sidewall radially to the breach wall is discontinuous from the motion of the bottom axially away from the interior of the case.
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Other embodiments of the present invention further enable an ability of a bottom corner of a pressure vessel to withstand high pressures. In
Various geometries of “spring” can be built into the casing 502 to tune it to a desired performance. The enables manufacture of thin wall and/or light weight casings to use thinner and/or lower strength materials. While prior designs have used austenitic stainless, the wall spring design of the present invention enables a use of a larger variety of lower strength material. Our design also enables thinner materials to be used to lower stress at a weak point.
In
In
Other embodiments may be included. For example, in one embodiment, an aluminum alloy base is replaced by a base of higher modulus of elasticity. The higher modulus material will not deform as much under a firing pressure and this prevent a tube from deforming to a limit of failure. Other material can include stainless steel and other iron alloys having both low cost and easy manufacturing. While an iron alloy base may weigh more than an aluminum alloy base and detracts from an overall weight reduction goal, a final assembly will still weigh less than existing brass ammunition cases. In higher length to diameter ratio designs like rifle casing, the effect of base weight is diminished.
In another embodiment, a typical ammunition case material is reduced up to 50% in thickness. In this design for current gun barrels designed to accept bullets and cartridges of defined dimensions, it is still necessary for an open end (bullet end) of the case to maintain both barrel fit on the outside diameter and bullet fit and retention on an inside diameter. To accomplish this, a compression ring is added to a neck of the tube such that the effective thickness of the assembled neck is returned to the design standard.
In still another embodiment, a casing can be designed to optimum weigh performance and simplicity of manufacture by requiring a new gun barrel breach configuration that accepts a reduced thickness casing. Here the casing, reduced up to 50% in thickness, does not need an additional compression collar on a neck.
In certain applications, it is desirable to have an ammunition casing that cannot be easily reused. A geometry of deformation can be created such that a deformation under firing is plastic and the casing does not return to its original shape, making the case more difficult or impossible to reload.
It would be appreciated by those skilled in the art that various changes and modifications can be made to the illustrated embodiments without departing from the spirit of the present invention. All such modifications and changes are intended to be within the scope of the present invention except as limited by the scope of the appended claims.
Claims
1. An ammunition case comprising:
- an elongate interior cavity for receiving a propellant and a projectile and extending along a longitudinal axis between a top end and a bottom end; and
- a bottom corner of the cavity having a reversed radius design supported by a shaped base.
2. The ammunition case of claim 1 wherein a casing encloses the elongate interior cavity, an exterior of the casing deformed in a lower area during manufacturing to exhibit a spring wall section.
3. The ammunition case of claim 1 wherein a casing encloses the elongate interior cavity, an exterior of the casing having a pattern of deformations directed inwardly.
4. The ammunition case of claim 3 wherein the pattern of deformations are dimples of varying geometries.
5. The ammunition case of claim 3 wherein the pattern of deformations are a single row of dimples.
6. An ammunition case comprising:
- an elongate interior cavity for receiving a propellant and a projectile and extending along a longitudinal axis between a top end and a bottom end; and
- a bottom corner of the cavity having a broad radius design supported by a shaped base.
7. The ammunition case of claim 6 wherein a casing encloses the elongate interior cavity, an exterior of the casing deformed in a lower area during manufacturing to exhibit a spring wall section.
8. The ammunition case of claim 6 wherein a casing encloses the elongate interior cavity, an exterior of the casing having a pattern of deformations directed inwardly.
9. The ammunition case of claim 8 wherein the pattern of deformations are dimples of varying geometries.
10. The ammunition case of claim 8 wherein the pattern of deformations are a single row of dimples.
11. The ammunition case of claim 8 wherein the pattern of deformations are one or more circumferential rings.
12. An ammunition case comprising:
- an elongate interior cavity for receiving a propellant and a projectile and extending along a longitudinal axis between a top end and a bottom end; and
- a bottom corner of the cavity having an angle/radius combination supported by a shaped base.
13. An ammunition case comprises:
- a case, the case having a wall deformed in a pattern of deformations directed inwardly, enabling a balance of outer profile maintenance for general loading and handling while giving spring characteristics of in an axial direction.
14. The ammunition case of claim 13 wherein the pattern of deformations comprises grooves or dimples of varying geometries.
15. An ammunition case comprising:
- an elongate interior cavity for receiving a propellant and a projectile and extending along a longitudinal axis between a top end and a bottom end; and
- having one or more grooves rolled into the sidewall above a bottom corner.
Type: Application
Filed: May 2, 2018
Publication Date: Nov 8, 2018
Applicant: The Evans Findings Company, Inc. (East Providence, RI)
Inventor: Peter EVANS (East Providence, RI)
Application Number: 15/969,453