US3658007A

US3658007A - Hollow bursting charge

Info

Publication number: US3658007A
Application number: US804852A
Authority: US
Inventors: Ludwig Bucklisch
Original assignee: Dynamit Nobel AG
Current assignee: Dynamit Nobel AG
Priority date: 1968-03-08
Filing date: 1969-03-06
Publication date: 1972-04-25
Anticipated expiration: 1989-04-25
Also published as: FR1599650A; DE1696660A1; GB1251158A; BE729489A; NL6816873A

Abstract

The primer ignites the adjacent conically shaped shell of ignition transmitting explosive, which in turn annularly ignites the main explosive charge, which main explosive charge has two axially extending conical recesses pointed towards each other, the rear of which receives therein the forward conical surface of an inert element that has a rearwardly extending conical surface received within the ignition transmitting shell. A conically shaped shell bottom piece may be provided around the ignition transmitting explosive with a complementary type fit and a transverse loose fit with the interior rear conical surface of the jacket, or the interior conical surface of the jacket may receive the complementary exterior surface of the ignition transmitting shell directly.

Description

UnIted States Patent [151 3,6 Bucklisch [4 1 Apr. 25, 1972 [541 HOLLOW BURSTING CHARGE FOREIGN PATENTS 0R APPLICATIONS [72] Inventor: Ludwig Bucklisch, Rhondorf, Germany 714,747 9/1954 Great Britain ..l02/24 HC [73] Assignee: Dynam Nobel Akuengesenschafl 970,395 9/1964 Great Britain 102/24 HC Trolsdorf Germany Primary ExaminerVerlin R. Pendegrass Filed! 1969 Attorney-Craig, Antonelli & Hill 4 PP 80 I852 57 ABSTRACT [30] Foreign Application Priority Data 'Ijhe primerignites the adjacent co ically shaped shell of ignitIon transmitting explosive, whIch In turn annularly Ignites the Mar, 3, 1968 Germany up 16 96 660-2 main explosive charge, which main explosive charge has two axially extending conical recesses pointed towards each other, [52] U.S. Cl ..102/24 HC, 102/56 the rear of which receives therein the forward Conical Surface [51] I 1/02 of an inert element that has a rearwardly extending conical [58] Field Of SCII'Ch 102/24 HC, 56 Surface received within the ignition transmitting She A mcally shaped shell bottom piece may be provided around the [56] References Cited ignition transmitting explosive with a complementary type fit UNITED STATES PATENTS and a transverse loose fit with the interior rear conical surface of the acket, or the interlor conical surface of the acket may 2, 1957 102/24 HC receive the complementary exterior surface of the ignition ,02 ,83 96 102/24 HC transmitting shell directly. 3,034,393 5/1962 ...lO2/24

HC

3,45 l ,3 39 6/ l 969 Precoul 102/24 HC 4 Claims, 2 Drawing Figures PATENTED APR 2 5 1972 FIG. I

INVENTOR LUDWIG BUCKLISCH W 1711M I ATTORNEYS HOLLOW BURSTING CHARGE BACKGROUND OF THE INVENTION With axially symmetrical hollow bursting charges having a primer in the center of the rear, ignition will be propagated in a point-like manner at the point of ignition and from there the detonation is propagated in accordance with the distribution of the bursting charge. A more favorable ignition progression is attained by providing an areal or annular zone of ignition for the main bursting charge; this is done by serially interposing an ignition transmitting charge between the primer and the main bursting charge, to annularly ignite the main bursting charge. If a conical insert is provided in the front face of the hollow bursting charge with an aperture angle of about 60 to 120, the detonation waves will advantageously impinge on the insert with a steep angle.

In order to obtain an annular ignition zone for the main bursting charge, it is known to arrange a disk-shaped inert body between the primer and the bursting main charge, which inert body consists of a substance having a relatively low sound velocity, for example, synthetic material, plaster of Paris, or the like, which will delay the direct ignition in the axial direction so that ignition will first of all take place radially of the main bursting charge after detouring the inert body. Thereby, an annular ignition distribution of the main bursting charge is obtained, and by appropriately shaping the inert body, the angle of impingement of the detonation front with respect to the main bursting charge may be influenced.

With a hollow bursting charge of the above type, it is proved to be quite difficult to manufacture so that predictable uniform characteristics may be obtained. It has been found that only minor assymmetries of the elements of the explosive charge with respect to the center line will perceptively impair the efficiency of the hollow bursting charge. In order to obtain a uniform, good formation of the hollow charge flash or jet, the position of the explosive charge with respect to the casing or jacket is of considerable importance in the axial as well as the radial directions. Great efforts have been expended in order to obtain a high degree of accuracy during the manufacture of the individual parts and during the assembly of the hollow bursting charge. This expenditure necessary for the production, as well as the great number of rejects unavoidable, in particular during the manufacture of specially formed charges, is the cause for the conventional hollow explosive charges being rather undesirable in many respects.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hollow explosive charge so that the detonation waves will impinge on the main explosive charge and conical insert at a favorable angle, which charge may be manufactured and assembled with a relatively low expenditure of money and material. This is accomplished, in accordance with the invention, by assembling all the explosives in one jacket together with an inert element and a conical insert and conically offsetting the jacket encompassing the hollow explosive charge on its interior toward the primer for reception of the conical shell, ignition transmitting explosive contacting the primer at preferably its flattened tip. The inert body is provided as a double cone received within the inner conical surface of the ignition transmitting shell and a conical bore in the main bursting charge, respectively. In this manner, the inert body may be maintained in a centered position within the jacket, if necessary, during the assembly process with respect to the primer by means of a suitable device. All of the conical surfaces of the explosive elements have axes that are congruent.

Due to the conical shape of the various structural components, a geometrically simple and accurate centering is provided in the direction of the axis of the device during the assembly step, and at the same time, the objective is achieved that the surfaces of two adjacent elements are exactly congruent. The advantages of the annular distribution of the ignition for the main explosive charge are exploited to their fullest extent, and it is thus accomplished that the hollow explosive charge of the present invention has good detonating properties and can be manufactured on a large scale in an expensive and simple manner for the first time.

With respect to the manufacturing, it may be impossible or impractical to provide exactly complementary conical surfaces for the inside surface of the jacket and the outer conical surface of the ignition transmitting explosive shell or it may be desirable to provide for compensation for assymmetries that cannot be eliminated by other means. For these purposes, in accordance with a further development of the present invention, a conical shell bottom section may be provided with a conical exterior surface received within the conical end of the jacket and a conical interior surface receiving therein the ignition transmitting shell. The outside conical surface of the bottom piece will preferably have substantial play in the transverse direction with respect to the jacket but have a tight fit for its internal surface with respect to the ignition transmitting explosive shell.

During the production of any two mutually complementary cones, it is preferable to employ tools that have been manufactured on the same machine tool, with the identical adjustments of the machining devices.

BRIEF DESCRIPTION OF THE DRAWING Further objects, features and advantages of the present invention will become more clear from the following detailed description of the drawing, wherein:

FIG. 1 is an axial cross-sectional view taken through a hollow explosive charge according to the present invention; and

FIG. 2 is an axial cross-sectional view taken through another embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWING As shown in FIG. 1, the hollow explosive charge has a slightly conical tubular jacket or casing 8 provided at one end with an inclined jacket bottom 2 having a conical interior surface and terminating in a rear portion receiving therein the primer 6. The primer 6 is immediately adjacent to and ignites the conical shell ignition transmitting explosive l, which is slightly truncated at its tip adjacent primer 6. The outer conical surface of the shell 1 is accurately complementary to the interior surface of the bottom 2 and has its interior conical surface accurately complementary to the exterior adjacent conical surface of the inert element or body 3, which is shaped as a double cone with or without truncated front or rear ends. The inert body 3 may be constructed of metal, synthetic material, plaster of Paris, or the like, and the cone thereof directed to the front fits into a corresponding internal conical surface of the main explosive or bursting charge 4. The ignition transmitting explosive 1 contacts the main explosive charge 4 along a surface that is an extension of the rearward conical surface of the inert body 3.

The jacket 8 may be made of metal and is provided with a conical insert 5 extending within the complementary-formed conical bore of the main explosive charge 4 on the end opposite the rear primer 6. The detonation waves will thus be propagated from the primer 6 by way of the ignition transmitting element 1 to the main explosive charge 4, with the inert body being circumvented. Within the inert body 3, the waves will propagate so slowly that they arrive with a delay at the main explosive charge in order to continue the detonation in the axial direction. The detonation waves thus impinge on the conical insert 5 with a steep angle. As shown in FIG. 2, the second embodiment of the present invention employs a jacket 8 having a slightly conical taper on its exterior to the primer 6. As in the embodiment described with respect to FIG. 1, the inert body 3 is shaped as a double cone and is enveloped, on the one hand, by the main explosive charge 4, and on the other hand, by the ignition transmitting explosive l, which is shell shaped. The outer conical surface of the ignition transmitting explosive 1 does not directly contact the bottom 2 of the jacket 8, but instead extends at a larger angle with a space therebetween. The space is filled by a bottom piece 7, which rests, on the one hand, on the internal surface of the jacket 8 and, on the other hand, complementarily engages the outer surface of the ignition transmitting explosive 1. In order to obtain a satisfactory detonating process, it is essential that the ignition transmitting explosive l, the inert body 3 and the explosive charge 4 fit very accurately with respect to each other; the bottom piece 7 need not contact the jacket 2 in an accurately fitting manner; rather, this bottom piece 7 may be provided with transverse play with respect to the jacket 8 to compensate for assymmetries of the individual explosive and inert parts with respect to one another.

The manufacture of the identical conical shapes for interfitting conical surfaces may be suitably accomplished with tools, for example, pressing dies and drawing tools, of corresponding conical shape, which tools will be produced on the same machine tool with the same setting for the machining operations, so that any unevenness which might occur is compensated for during the assembly of the mating parts.

Although two embodiments have been specifically described and shown in the attached drawing, for purposes of illustration, further embodiments, variations and changes are contemplated.

It is claimed:

1. An axially symmetrical explosive device with annular ignition comprising: a rear primer, a main explosive charge having conically shaped front and rear recesses disposed in an axially symmetrical manner and pointed toward each other, the rear recess covering only a central portion of the rear of said main charge, the peripheral region of said main explosive charge surrounding said rear recess having a frusto-conical surface tapered in the rearward direction; a conical insert in the front recess of said main explosive charge; a jacket surrounding said main explosive charge and having a conically shaped interior surface pointing rearwardly to said primer; an ignition transmitting explosive within said conically shaped interior surface of said jacket and having the shape of a conical shell with its rear tip adjacent said primer and its front periphery complementary to and receivable on the remaining peripheral region of said main explosive charge; an inert body having oppositely pointed first and second conical exterior surfaces, said first surface being complementary to and received within the conical surface of said ignition transmitting explosive and the second surface complementary to and received within the rear conical recess in the main explosive charge whereby the axes of all said conical surfaces are congruent with the main axis of the device by the provision of exclusively conical contact surfaces on the main explosive charges, the insert, the jacket, the ignition transmitting explosive and the inert body.

2. The explosive device according to claim 1, including a conical shell bottom piece mounted between and complementary to each of the conical shaped interior surface of said jacket with transverse play and the conical exterior surface of said ignition transmitting explosive without play.

3. The device according to claim 1, wherein said ignition transmitting explosive shell is frusto-conical on its exterior.

4. The device according to claim 3, wherein the interior surface of said ignition transmitting shell is frusto-conical and the complementary exterior surface of said inert body is frustoconical.

Claims

4. The device according to claim 3, wherein the interior surface of said ignition transmitting shell is frusto-conical and the complementary exterior surface of said inert body is frusto-conical.