US 3320888 A
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y 1967 F CHURCHILL CONTINUOUS ROD WARHEAD 2 Sheets-Sheet 1 Filed March 51, 1965 INVENTOR F RANK [2' CHURCH/LL ATTORNEY AGENT y 1957 F. F. CHURCHILL 3,320,888
CONTINUOUS ROD NARI- BAD Filed March 51, 1965 2 Sheets-Sheet i 3,32%,888 Patented May 23, 1967 3,329,888 CUNTINUGUS R01) WARHEAD Frank F. Churchili, Dahlgren, Va., assignor to the United States of America as represented by the Secretary of the Navy Filed Mar. 31, 1965, Ser. No. 444,471 Claims. (Cl. 102-67) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
This invention relates generally to continuous rod warheads, and more particularly to means for preventing premature failure of the rods in the vicinity of the welded hinge joints between the rod pairs.
The construction and operation of continuous rod warheads are explained in detail in United States Patent No. 3,160,099 of the common assignee. The warhead is disposed around the entire exterior periphery of a high explosive charge, and consists of a plurality of rods of generally rectangular cross-section which are substantially aligned with the longitudinal axis of the warhead. Alternate opposite ends of the rods are rigidly connected by a welded joint or hinge, so that the warhead will be propelled outwardly as a single expanding ring when the explosive charge is detonated.
Continuous rod warheads are subjected to very severe conditions during and immediately after the detonation of the explosive charge. Explosive pressures resulting from the detonation of the charge will reach several million p.s.i. These pressures may be applied to the rods of the projectile at loading rates of up to 25,000 feet per second. As a result of the explosion, the continuous rod warhead will be blasted outwardly as an expanding ring at a velocity of several thousand feet per second. Following detonation of the charge, the expanding rods unfold and the maximum bending and torsional stresses are encountered in the hinge joint zone. Furthermore, the shock wave resulting from the explosion tends to explosively harden the steel rods.
The effectiveness of these warheads is largely dependent upon the continuity of the ring. If the ring breaks prematurely, the possibility that the target will escape undamaged is greatly increased. Hence it is essential that the structural integrity of the hinge joint between each pair of rods be maintained until the ring has fully expanded. The combination of the explosive hardening at the hinge joint and the concentration of maximum stresses which occurs there results in a tendency for premature failure in the joint zone. The effectiveness of the Warhead is thercfore greatly reduced.
Accordingly, it is the principle object of this invention to increase the reliability and effectiveness of a continuous rod warhead.
It is a further object of this invention to reduce the likelihood of premature failure of the hinge joints of a continuous rod warhead without the addition of any substantial weight or space penalty.
It is a still further object of this invention to provide an improved hinge joint which will not be subject to the excessive stresses heretofore encountered by the prior art joint configurations.
Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:
FIG. 1 is a fragmentary perspective view of a portion of a continuous rod warhead;
FIG. 2 is a fragmentary perspective view showing a portion of the continuous rod mat in a partially expanded condition;
FIG. 3 is a perspective view of a single substantially fully expanded, hinge joint made in accordance with the prior art technique;
FIG. 4 is a series of elevations of a single rod element; and
FIG. 5 is an exploded perspective view of a joint between a single pair of rods.
A portion of the continuous rod mat 11 is shown in perspective in FIG. 1. Mat 11 is disposed around the entire outer periphery of the projectile and is adjacent an annular explosive charge 12. Mat 11 comprises a double layer of rods. The inner rod layer consists of a plurality of parallel adjacent rods 13 while the outer layer consists of a plurality of parallel adjacent rods 14. Rods l3 and and 14 are identical and therefore completely interchangeable. Each rod is welded at its respective ends to one of two mutually adjacent rods of the adjacent layer. This is made possible by a slight misalignment between the parallel rods of the outer layer and the parallel rods of the inner layer. These welded joints thus define a series of rod pairs, each pair including an inner rod 13 and an outer rod 14.
FIG. 3 is illustrative of the configuration of a fully expanded joint made in accordance with the methods of the prior art. The configuration of the joint is such that the outer face of inner rod 13 is Welded to the inner face of the outer rod 14. As the hinge joint expands following detonation of the charge, the individual rods twist as well as spread apart, as shown in FIG. 3. This phenomenon results from the constraint placed on each end of the rods by the joints of the expanding ring. The resulting combination of both bending and torsional stresses in the vicinity of the joint frequently results in premature failure of the joint.
A portion of a partially expanded mat 11 including several hinge joints made in accordance with the present invention is illustrated in FIG. 2. The configuration of the rods in the vicinity of the joint is best seen by reference to FIGS. 4 and 5. The rods illustrated in FIGS. 1, 2, 3, and 5 are each viewed from the same relative position for ready comparison. A comparison of FIG. 5 with FIG. 3 indicates that one of the primary differences between the hinge joint of the present invention and that of the prior art is that, although the rods are still disposed one outside of the other, the joint interface of the present invention is in a vertical plane while that of the prior art is in a horizontal plane. This is accomplished by reducing the width of the rod in the joint zone to one-half that of the central portion of the rod and increasing the depth at the joint to twice that of the central portion of the rod. The transition from the central cross-section to that at the joint is characterized by large radii, so that the stress concentration factors at the joint will be as low as possible. The reduction of the rod width in the transition zone facilitates bending and twisting of the rod, and reduces the stresses induced during expansion of the hinge joint.
As is shown in FIG. 4, the edges of the joint face are bevelled at 15 so as to provide a groove between the mated inner and outer rods of each pair to receive weld filler material. These bevelled surfaces have been omitted from FIG. 5 for clarity. It is contemplated that the end portions of the rods could be most readily fabricated by forging with a subsequent machining operation.
The unique joint configuration provided by the present invention substantially reduces the likelihood of premature failure of the expanding ring. Several factors contribute to the improved performance of this invention. The depth of the rod cross-section which is subjected to bending and torsion, i.e., the width, as illustrated in the figures, is substantially reduced over that of the prior art joint configuration. This new configuration,
coupled with the lack of abrupt transitions between the central portion of the rod and the joint face, greatly reduces the stresses which arise in the joint zone during expansion of the ring.
An additional factor which improves the performance of the joint is the change in orientation of the joint interface from horizontal, as in the prior art, to vertical. This change changes the character of the stresses to which the weld is subjected. In the prior art joint, the weld subject to both tensile and shear stresses, While the joint of the present invention is subject essentially to only tensile stresses. The elimination of the shear stresses, to which the weld has less resistance than to tensile stresses, greatly increases the durability of the joint.
Furthermore, since the reduced cross-section permits the rod to bend so readily, the joint has an opportunity to expand to a greater extent before the weld is subjected to any appreciable stresses.
Although the invention has been illustrated as embodied in a warhead having a double layer of rods, it is to be understood that it could be readily incorporated into a warhead having any number of multiple rod layers. Similarly, although the invention has been disclosed as embodied in a cylindrical configuration, it might also be utilized in a conical Warhead, or a Warhead having an outer periphery defined by any other type of desired surface of revolution.
Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
What is claimed is:
1. A continuous rod warhead for an ordnance device, the outer periphery of which is defined by a surface of revolution, comprising:
a plurality of rods substantially aligned with the longitudinal axis of the device and disposed around the outer periphery of the warhead in a plurality of layers;
the ends of each respective rod being characterized by an enlarged tab-like planar portion, Which plane is defined by the axis of the respective rod and an intersecting radial of the warhead;
each tabbed end of the respective rods being securely joined in the form of a lap joint to the corresponding tabbed end of a rod of an adjacent layer.
2. The warhead of claim 1 wherein said ordnance device is substantially cylindrical.
3. The warhead of claim 1 wherein said rods are rectangular.
4. A continous rod Warhead mat comprising:
a plurality of rods, each characterized by a substantially constant transverse cross-sectional configuration through-out a substantial portion of the rod length intermediate the rod ends;
the respective end portions of each of said rods being characterized by a transverse width substantially onehalf the transverse width of the central portion of said rod, and further characterized by a transverse depth substantially twice the transverse depth of the central portion of said rod;
the respective end portions of each of said rods being so disposed relative to the central portion of said rod that the longitudinal axis of the central portion of said rod lies in the plane of one face of each of said end portions the rods being arranged in layers, the end portions of the rods of adjacent layers being Welded together.
5. An element of a continuous rod warhead mat comprising:
a rectangular rod characterized by a substantially constant transverse Width and depth throughout a substantial portion of the rod length intermediate the rod ends;
the respective end portions of said rod being characterized by a transverse Width substantially one-half the transverse width of the central portion of said rod, and further characterized by a transverse depth substantially twice the transverse depth of the central portion of said rod;
the respective end portions of said rod being so disposed relative to the central portion of said rod that two mutually perpendicular edges of a transverse crosssection of said end portions coincide with axial projections of homologous edges of a transverse cross-section of the central portion of said rod.
References Cited by the Examiner UNITED STATES PATENTS Re. 7,156 6/1876 Lewis et al. 29l00 154,990 9/1874 Keene et al. 287104 3,004,785 10/1961 Wolf 287-64 3,160,009 12/1964 Nooker 10267 3,223,036 12/1965 Anspach 10267 SAMUEL FEINBERG, Primary Examiner.
BENJAMIN A. BORCHELT, Examiner.
W. KUIAWA, Assistant Examiner.