US 3732816 A
A hollow charge with an insert of progressive and degressive wall thickness, respectively, wherein the insert has at least partly curved generating lines. The oppositely disposed outer and inner generating lines of the insert have the same line course, yet are rotatably displaced relative to each other for a predetermined angle within a sectional plane.
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Description (OCR text may contain errors)
nited States Patent [1 1 Miiller May 15, 1973  HOLLOW CHARGE WITH AN INSERT  References Cited gIILIIZIE-IOGRESSIVE 0R DEGRESSIVE UNITED STATES PATENTS 2,974,595 3/1961 Mohaupt ..102 24 HC Inventor: Helmut Rhynern-Kump, 3,103,882 9/1963 Gilliland Germany 3,437,036 4/1969 Franzen et al. ..102/24 HC  Assignee: Firma Rheinmetall GmbH, Dussel- FOREIGN PATENTS OR APPLICATIONS dorf, Germany 1,327,804 4 1963 F ..l02 24 HC 22 Filed: Sept. 10,1970 I l Primary Examiner-Verlin R. Pendegrass ] Appl' 7109l Attorney-Ernest G. Montague  Foreign Application Priority Data  ABSTRACT A hollow charge with an insert of progressive and Sept Germany 19 46 959'] degressive wall thickness, respectively, wherein the in-  us Cl 102/24 C sert has at least partly curved generating lines. The op-  F42, 3/08 positely disposed outer and inner generating lines of  Field ofQilli'fIIIfffIIf.111116554 24 c 56 the have the Same course Y are rotatably displaced relative to each other for a predetermined angle within a sectional plane.
2 Claims, 4 Drawing Figures 1 HOLLOW CHARGE WITH AN INSERT OF PROGRESSIVE OR DEGRESSIVE WALL The present invention relates to hollow charges with circular-symmetrical inserts, the wall thicknesses of which increase progressively or diminish degressively starting from the axis toward the insert base and the outer and inner generating lines of which are completely or also partly curved lines.
This type of insert is of particular importance, because by the application of continuously increasing or decreasing insert wall thicknesses and embodiments curved from the apex to the base maximum, stretched and thereby deeply effective hollow charge-radiations and-projectiles, respectively, can be produced.
Such inserts are designed, aside of sometimes required constructively caused deviations at the apex point and on the base of the insert, respectively, over the total length and over the main part of the generating lines, respectively, progressive or degressive. They are characterized by the quotient x of the wall thickness extreme values as x-times progressive or degressive.
In spite of the fact that the course of the generating lines and of the wall thicknesses of these known inserts is constant, the hollow charges equipped therewith lack often the desired depth effect in the target material, because during the blow-up, the concentration of the insert mass and, thereby, the formation process of a long stretched radiation and projectile, respectively, does not take place without disturbances, as premature tearing of the insert material, tube formation and breakthroughs of detonating products.
As newer tests clearly indicate, these drawbacks are due particularly in highly effective hollow charges with thin walled inserts essentially in view of the unfavorable course of the so-called local progressivity and degressivity, respectively, x,,=s,,+1/s,,=f(r), which is related to small but equally large sections and annular zones Ar,
respectively, and wherein s is the local insert wall thickness measured normally to the outer generating line, n is the index number continuing to the inner limit of the section Ar and r is the distance of the considered zone Ar from the insert axis. The local progressivity is now of particular importance for the collapse or forming process of the insert. The larger, for instance, the local progressivity and thereby the difference between the adjacent wall thicknesses s and s,,+l the larger is the difference of the speeds assigned by the demolition'impulse about perpendicularly to the generating line, that means, the faster the particles with the weaker wall thickness rush ahead, so much larger is also the resistance against the buckling of the insert mass inwardly and so much more is the insert material involved by the further floating. From this it appears, that in case of strong variations of the local progressivity x,,=f(r) of the forming process up to the annular tearing of the insert can be disturbed. The term x,,=f(r) is thus a criterion for the forming process of the insert. It has been shown empirically, that between the latter and the character of the x -curve a connection exists.
It is, therefore, one object of the present invention to provide a hollow charge with the insert of progressive or degressive wall wherein during the blow-up of the hollow charge an undisturbed forming process of the projectile is obtained.
The present invention starts thereby from the new blow-technical recognition, that for the disturbancefree formation of the hollow charge-radiation or projectile, a x -curve of the local progressively and degressivity, respectively, and of a constant character above the axial distance r and without recognizable buckling, is to be aimed at and the solution of this problem in accordance with the present invention is characterized by the fact, that the oppositely disposed outer and inner generating lines of the insert extending in a section plane through the insert axis have the same line formation, however, are rotated within the section plane relative to each other about an angle.
During the production of such insert, one starts suitably from a pre-given outer contour (outer generating line) of the insert and one obtains the corresponding inner generating line by simple rotation of the given outer contour (gage). The wall thicknesses to be provided at the point and at the apex, respectively, and at the base of the insert can be chosen thereby within wide limits corresponding to the prevailing purpose.
As a further advantage, an exact adjustment of the tools required for the production of the insert and thereby an optimum in the precision of the course of the wall thickness of the insert can be brought about, due to the coincidence of the line courses of the inner and the outer generating lines, whereby an important presumption for the efficiency of the hollow charge is fulfilled.
With these and other objects in view, which will be come apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawing, in which:
FIG. 1 is a schematic fragmentary section through a hollow charge insert;
FIG. 2 is a hollow charge with a progressive insert; and
FIGS. 3 and 4 are further inserts with progressive and degressive course of the wall thicknesses, respectively.
Referring now to the drawing, FIG. 1 serves the explanation of the previously mentioned progressivity formulas.
In FIGS. 2-4 the course of the outer generating line of the inserts is indicated with A-B and the course of the inner generating line is A'-B. The inner generating lines A B have always the same line course of the corresponding outer generating lines A-B, whereby the line courses are angularly rotated for a small angle, in accordance with the progressivity of the wall thickness. The practical realization of the present invention can take place suitably in such manner, that a gage set for the production of the outer generating lines is rotated for a small angle, whereby the corresponding inner generating line results.
While I have disclosed several embodiments of the present invention, it is to be understood that these embodiments are given by example only and not in a limiting sense.
1. A hollow charge with an insert of progressive wall thickness,
said insert having inner and outer surfaces comprising at least partly curved oppositely disposed inner and outer generating lines within a sectional plane, and
said oppositely disposed inner and outer generating lines of said insert being the same, yet rotatably dis- 3 4 placed relative to each other by a predetermined and angle within said f l said oppositely disposed inner and outer generating 1:: hollow charge wlth an Insert of degresswe wan lines of said insert being the same, yet rotatably dis- 1C ess, i said insert having inner and outer surfaces compris- 5 placed f f eac h other by a predetermmed ing at least partly curved oppositely disposed inner angle Wlthm Said Secuonal P and outer generating lines within a sectional plane,