Title:
AMMUNITION ROUND WITH NON-RIGID ATTACHMENT OF PROJECTILE TO CARTRIDGE CASE
United States Patent 3832951
Abstract:
A non-rigid connection is made between a non-metallic, combustible, cylincal cartridge case body having a centrally-apertured domed front end and a projectile or shell having a concave outer annular portion engaging the domed front end and a threaded central attachment plug extending through the case aperture, by means of a locking ring threaded onto the plug to clamp the front end against the projectile and a thin annular spring washer having its inner periphery interposed between the ring and the inner periphery of the front end and its outer periphery engaging the front end outwardly of the ring.
US Patent References:
Ammunition
Smith - April 1946 - 2399398
Cartridge case
Stadler - November 1966 - 3288066
INTEGRATED ROUND WITH COMBUSTIBLE CARTRIDGE
Larson - April 1972 - 3658008
EXPENDABLE CASE WITH VENTED BASE CAP
Scanlon - October 1972 - 3696749
COMBUSTIBLE CARTRIDGE CASE
Zimmerman - December 1972 - 3706279
Ammunition
Smith - April 1946 - 2399398
Cartridge case
Stadler - November 1966 - 3288066
INTEGRATED ROUND WITH COMBUSTIBLE CARTRIDGE
Larson - April 1972 - 3658008
EXPENDABLE CASE WITH VENTED BASE CAP
Scanlon - October 1972 - 3696749
COMBUSTIBLE CARTRIDGE CASE
Zimmerman - December 1972 - 3706279
Inventors:
Katz, Daniel (Brooklyn, NY)
Syben, Peter H. (Weaver, AL)
Syben, Peter H. (Weaver, AL)
Application Number:
05/324267
Publication Date:
09/03/1974
Filing Date:
01/17/1973
View Patent Images:
Export Citation:
Assignee:
The United States of America as represented by the Secretary of the Army (Washington, DC)
Primary Class:
International Classes:
F42B5/073; F42B5/18; F42B5/00; F42B5/02
Field of Search:
102/DIG.1,38,40,43R,43F,43P,44,49.7,92.3,92.4
Primary Examiner:
Engle, Samuel W.
Assistant Examiner:
Tudor H. J.
Attorney, Agent or Firm:
Kelly, Edward Berl Herbert Webb Thomas J. R.
Claims:
What is claimed is
1. A round of ammunition including:
2. A round as in claim 1, wherein substantially the entire front face of said washer is in contact with said front end.
3. A round as in claim 2, wherein the outer diameter of said washer is nearly equal to that of said front end.
4. A round as in claim 1, wherein said front end is domed.
5. A round as in claim 4, wherein the cross section shape of said washer prior to clamping is such that during assembly of the parts said outer periphery of said washer engages said domed end prior to engagement of said inner periphery with said front end, whereby said outer periphery resiliently engages said domed end after clamping.
6. A round as in claim 5, wherein said cross section shape prior to clamping is curved, with a curvature smaller than that of said domed end.
1. A round of ammunition including:
2. A round as in claim 1, wherein substantially the entire front face of said washer is in contact with said front end.
3. A round as in claim 2, wherein the outer diameter of said washer is nearly equal to that of said front end.
4. A round as in claim 1, wherein said front end is domed.
5. A round as in claim 4, wherein the cross section shape of said washer prior to clamping is such that during assembly of the parts said outer periphery of said washer engages said domed end prior to engagement of said inner periphery with said front end, whereby said outer periphery resiliently engages said domed end after clamping.
6. A round as in claim 5, wherein said cross section shape prior to clamping is curved, with a curvature smaller than that of said domed end.
Description:
BACKGROUND OF THE INVENTION
In a conventional fixed artillery round (e.g., 152 mm) the domed front end of the cartridge case body is rigidly attached by epoxy resin to a corresponding concave annular surface on the base of the projectile. To provide additional reinforcement, the projectile base includes a central plug that extends through a central aperture in the domed end and a locking ring threaded onto the plug to clamp the inner periphery of the domed end to the projectile. This attachment means, which has been used for over 10 years, has the following disadvantages:
1. Due to the rigid epoxy bond between the case and the projectile, the rounds often fail to pass the present rigid drop test and pull strength requirements;
2. The epoxy resin used for bonding the case to the projectile prevents quick non-destructive separation of the case and projectile for re-working of mal-assembled ammunition and results in a costly increase in scrap;
3. The epoxy resin sometimes produces objectionable residue in the barrel of the weapon during firing;
4. The overall cost of assembly including the need for exhaustive quality control is excessive.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a strong, reliable, non-rigid connection between a projectile and a non-metallic cartridge case body.
In accordance with the invention, a strong non-rigid connection is made between a non-metallic cartridge case body having an inwardly-extending front end with a central aperture and a projectile having an annular surface conforming to and engaging the case front end and a central attachment plug extending through the case aperture, by means of a locking ring threaded onto the plug and a thin annular spring washer having its inner periphery clamped between the ring and the inner periphery of the front end and its outer periphery engaging the front end outwardly of the locking ring. Preferably, the front end of the case body is curved in dome shape and the annular surface of the projectile is correspondingly shaped to fit the domed end. The spring washer may have an initial shape, prior to assembly and clamping, similar to the dome shape, or the washer may have an initial curvature greater than that of the domed case end, to cause the outer portion of the washer to resiliently engage the domed end after clamping.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a fixed round of ammunition in which the present invention is incorporated.
FIG. 2 is a side view, partially cutaway in axial section, of the round of FIG. 1.
FIG. 3 is a transverse section view taken on line 3--3 of FIG. 2.
FIG. 4 is a view similar to FIG. 2, showing the parts in an intermediate stage of assembly.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
FIGS. 1-4 illustrate the invention as incorporated in a 152 mm fixed round of artillery ammunition, for example. As shown in FIGS. 1 and 2, the round 1 includes a projectile 3 attached to a non-metallic cartridge case 5. The case 5 comprises a hollow cylindrical body 7 formed with an inwardly-extending front end portion 9 of dome shape terminating in an inner peripheral region 10 which defines a central aperture 11. The case body 7 is normally made of combustible material, e.g., felted nitrocellulose, which supplements the propelling charge and is consumed during firing. The rear end of the case body 7 is closed by a flanged base 13, normally made of the same material as the body 7, attached to the body 7 by cement 15, e.g., of nitrocellulose lacquer. The case 5 contains one or more bags 17 of propellant adapted to be ignited by a primer 19.
The projectile 3, which would normally be a high explosive shell, comprises a cylindrical base 21 having a base 23 formed with an outer concave annular portion 25, which conforms in shape to and snugly engages the domed front end 9 of the case 7, and a central plug portion 27 which extends through aperture 11 and has external threads 29. A locking ring 31, threaded onto the plug portion 27, rigidly clamps the inner periphery 10 of the domed end 9 against surface 25 of the projectile. As shown in FIG. 2, the outer diameter of ring 31 substantially smaller than the outer diameter of the domed end 9 to avoid rigid clamping of the outer portion of the domed end 9 against surface 25. For example, the radial dimensions of the ring 31 and the domed end 9 may be 7 and 30 mm, respectively.
In order to increase the pull strength of the connection between the projectile and the case and also produce a non-rigid connection that can absorb the shock encountered in drop tests without damage to the round, a thin spring washer 33, having an inner diameter substantially the same as the locking ring 31, and an outer diameter nearly equal to that of the domed end 9, is interposed between the ring 31 and the domed end 9. For example, a washer having a radial dimension of 25 mm may be used with the examples given above for the ring 31 and domed end 9. The initial cross section shape of washer 33 (prior to clamping of the parts) may be substantially the same as the shape of the adjacent surface of the domed end 9, in which case the washer 33 supports, or resists forward movement of, the end 9 without resilient engagement therebetween. To provide resilient engagement, the washer 33 may have an initial curvature smaller than the curvature of the domed end 9, as shown in a partially-clamped stage of assembly in FIG. 4, where R 1 and R 2 represent the radii of curvature of adjacent surfaces of the domed end 9 and washer 33, respectively, and R 2 > R 1 . In order to provide a strong resilient connection between the case and the projectile, the washer 33 must be made of a strong springy resilient material. The inner periphery 10 of the domed end 9 may be formed with cut-outs 35 leaving intermediate projections 37, for equalizing the gas pressure within the cartridge.
When a round of ammunition is dropped on a steel plate from a predetermined height, impact of either end with the plate exerts a bending force wherein the side of the connection opposite the point of impact is compressed and the same side of the connection tends to open up. With a conventional epoxy bond supplemented by a threaded connection without the spring washer in the 152 mm example given, the round generally failed at a drop height of about 2.5 feet and had a pull strength of only about 250 pounds. While the pulling force in the pull tests was exerted on the cartridge base 13, the cemented connection 15 was much stronger than the connection between the case and the projectile, so that the connection 15 never failed the pull tests. If the epoxy bond is omitted and the threaded connection without a washer is relied on, the connection is non-rigid, but is very weak, and fails to pass either the drop test or pull test requirements. On the other hand, rounds of ammunition of the 152 mm example incorporating the thin spring washer of the present invention consistently passed drop tests from 5 feet and pull tests of over 900 pounds, which constitute improvements of 100 and 260 percent respectively.
In a conventional fixed artillery round (e.g., 152 mm) the domed front end of the cartridge case body is rigidly attached by epoxy resin to a corresponding concave annular surface on the base of the projectile. To provide additional reinforcement, the projectile base includes a central plug that extends through a central aperture in the domed end and a locking ring threaded onto the plug to clamp the inner periphery of the domed end to the projectile. This attachment means, which has been used for over 10 years, has the following disadvantages:
1. Due to the rigid epoxy bond between the case and the projectile, the rounds often fail to pass the present rigid drop test and pull strength requirements;
2. The epoxy resin used for bonding the case to the projectile prevents quick non-destructive separation of the case and projectile for re-working of mal-assembled ammunition and results in a costly increase in scrap;
3. The epoxy resin sometimes produces objectionable residue in the barrel of the weapon during firing;
4. The overall cost of assembly including the need for exhaustive quality control is excessive.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a strong, reliable, non-rigid connection between a projectile and a non-metallic cartridge case body.
In accordance with the invention, a strong non-rigid connection is made between a non-metallic cartridge case body having an inwardly-extending front end with a central aperture and a projectile having an annular surface conforming to and engaging the case front end and a central attachment plug extending through the case aperture, by means of a locking ring threaded onto the plug and a thin annular spring washer having its inner periphery clamped between the ring and the inner periphery of the front end and its outer periphery engaging the front end outwardly of the locking ring. Preferably, the front end of the case body is curved in dome shape and the annular surface of the projectile is correspondingly shaped to fit the domed end. The spring washer may have an initial shape, prior to assembly and clamping, similar to the dome shape, or the washer may have an initial curvature greater than that of the domed case end, to cause the outer portion of the washer to resiliently engage the domed end after clamping.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a fixed round of ammunition in which the present invention is incorporated.
FIG. 2 is a side view, partially cutaway in axial section, of the round of FIG. 1.
FIG. 3 is a transverse section view taken on line 3--3 of FIG. 2.
FIG. 4 is a view similar to FIG. 2, showing the parts in an intermediate stage of assembly.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
FIGS. 1-4 illustrate the invention as incorporated in a 152 mm fixed round of artillery ammunition, for example. As shown in FIGS. 1 and 2, the round 1 includes a projectile 3 attached to a non-metallic cartridge case 5. The case 5 comprises a hollow cylindrical body 7 formed with an inwardly-extending front end portion 9 of dome shape terminating in an inner peripheral region 10 which defines a central aperture 11. The case body 7 is normally made of combustible material, e.g., felted nitrocellulose, which supplements the propelling charge and is consumed during firing. The rear end of the case body 7 is closed by a flanged base 13, normally made of the same material as the body 7, attached to the body 7 by cement 15, e.g., of nitrocellulose lacquer. The case 5 contains one or more bags 17 of propellant adapted to be ignited by a primer 19.
The projectile 3, which would normally be a high explosive shell, comprises a cylindrical base 21 having a base 23 formed with an outer concave annular portion 25, which conforms in shape to and snugly engages the domed front end 9 of the case 7, and a central plug portion 27 which extends through aperture 11 and has external threads 29. A locking ring 31, threaded onto the plug portion 27, rigidly clamps the inner periphery 10 of the domed end 9 against surface 25 of the projectile. As shown in FIG. 2, the outer diameter of ring 31 substantially smaller than the outer diameter of the domed end 9 to avoid rigid clamping of the outer portion of the domed end 9 against surface 25. For example, the radial dimensions of the ring 31 and the domed end 9 may be 7 and 30 mm, respectively.
In order to increase the pull strength of the connection between the projectile and the case and also produce a non-rigid connection that can absorb the shock encountered in drop tests without damage to the round, a thin spring washer 33, having an inner diameter substantially the same as the locking ring 31, and an outer diameter nearly equal to that of the domed end 9, is interposed between the ring 31 and the domed end 9. For example, a washer having a radial dimension of 25 mm may be used with the examples given above for the ring 31 and domed end 9. The initial cross section shape of washer 33 (prior to clamping of the parts) may be substantially the same as the shape of the adjacent surface of the domed end 9, in which case the washer 33 supports, or resists forward movement of, the end 9 without resilient engagement therebetween. To provide resilient engagement, the washer 33 may have an initial curvature smaller than the curvature of the domed end 9, as shown in a partially-clamped stage of assembly in FIG. 4, where R 1 and R 2 represent the radii of curvature of adjacent surfaces of the domed end 9 and washer 33, respectively, and R 2 > R 1 . In order to provide a strong resilient connection between the case and the projectile, the washer 33 must be made of a strong springy resilient material. The inner periphery 10 of the domed end 9 may be formed with cut-outs 35 leaving intermediate projections 37, for equalizing the gas pressure within the cartridge.
When a round of ammunition is dropped on a steel plate from a predetermined height, impact of either end with the plate exerts a bending force wherein the side of the connection opposite the point of impact is compressed and the same side of the connection tends to open up. With a conventional epoxy bond supplemented by a threaded connection without the spring washer in the 152 mm example given, the round generally failed at a drop height of about 2.5 feet and had a pull strength of only about 250 pounds. While the pulling force in the pull tests was exerted on the cartridge base 13, the cemented connection 15 was much stronger than the connection between the case and the projectile, so that the connection 15 never failed the pull tests. If the epoxy bond is omitted and the threaded connection without a washer is relied on, the connection is non-rigid, but is very weak, and fails to pass either the drop test or pull test requirements. On the other hand, rounds of ammunition of the 152 mm example incorporating the thin spring washer of the present invention consistently passed drop tests from 5 feet and pull tests of over 900 pounds, which constitute improvements of 100 and 260 percent respectively.