US3159102A

US3159102A - Explosive demolition arrangement

Info

Publication number: US3159102A
Application number: US167550A
Authority: US
Inventors: Riedl Hans-Joachim; Schluter Heinz
Original assignee: Wasag Chemie AG
Current assignee: Wasag Chemie AG
Priority date: 1956-07-27
Filing date: 1962-01-22
Publication date: 1964-12-01
Anticipated expiration: 1981-12-01
Also published as: DE1130344B; BE559473A; CH372234A; GB917886A; GB855932A; NL264322A; CH379990A; DE974557C

Description

1964 HANS-JOACHIM RIEDL ETAL 3,

EXPLQSIVE DEMOLITION ARRANGEMENT Filed Jan. 22, 1962 2 Sheets-Sheet 1 INVENTOR. A M veal/m. 2&4: BY Heinz (Q' 1954 I HANS JOACHIM RIEDL ETAL 3,159,102

FIG. 2

INVENTORS; m. PM BY 1 545% United States Patent 13 Claims. 0L 102 22 The present invention is concerned with an explosive demolition arrangement and method and, more particu larly, the present invention is concerned with directing and increasing the effect of explosive demolition devices.

The present application is a continuation-in-part of our co'pehding application Serial No. 674,726, filed July 2 9, 1957, now abandonedand entitled Method of Directmg and Increasing the Effects of Explosive Charges.

According to the present invention, the demolition of piercing effect achieved by detonating an explosive charge is increased by arranging a thin-walled hollow body or sleeve in front of the explosive charge, i.e. interposed between the front face of the explosive charge and the target or object to be demolished. The interposed sleeve is so arranged as to Converge in the direction from the charge towards the object to be detonated. The increased anectivehess of a given demolition charge which is achieved by interposition of such sleeve is all the more surprising since the hollow body or sleeve which may consist of any suitable material such as metal, wood, plastic, mill-board or the like may be destroyed upon detonationof the charge. Particularly good results are achieved by using a hollow sleeve of a material of relatively high specific gravity such as lead or by giving it a particularly sturdy constructibill The hollow body of sleeve may also be composed of several layers. The increase of the blasting ffbct of the hollow body is to a large degree dependent on the angle of inclination of the wall of the hollow body, i.e. on the apex angle or on the angle between the axis the generatrix of the hollow, preferably frusto-conical body which is used as an interposed sleeve between the charge and the object to be demolished.

I As shown by the short outline above, it is an object of the present invention to improve the effectiveness of demolition charges.

It is a further object of the present invention to increase the effect of a given demolition charge on a given object to be demolished, by interposing between the charge and the object a guide sleeve which converges in the direction from the explosive charge towards the object in the manner set forth in more detail below, so as to obtain an improved result in a simple and economical manner.

Other objects and advantages of the present invention will become apparent from a further reading of the disclosure and of the appended claims.

With the above and other objects in view, the present invention contemplates a demolition arrangement, comprising, in combination, an object to be subjected to explosive force, an explosive device including an explosive charge of which the front face is spaced from and directed toward the surface of the object, and a guide sleeve interposed at least between the explosive device and the object, the guide sleeve substantially surrounding the front face of the explosive charge and converging in the direction towards the object so as to limit the lateral ex-' pension of the exploding charge and concentrate the same toward the surface of the object.

According to the method of the present inventiorn the effect of an explosive charge is concentrated within a limited cross-sectional area by arranging an explosive charge adjacent and in close proximity to an object to be subjected to explosive force in such a manner that the path of the explosive force generated upon detonating the charge will intersect a surface portion of the object, interposing between the explosive charge and the object a guide sleeve extending at a point spaced from the charge into the peripheral portion of the path of the explosive force, and detonating the explosive charge whereby the path of the explosive force will be narrowed so as to concentrate the effect thereof within a cross-sectional area which is smaller than the cross-sectional area of the path in the immediate vicinity of the explosive charge.

For easier operation it would be expedient to enclose the explosive in a jacket e.g'. of sheet-iron of different thick ness. The conical hollow body and the jacket of the explosive can be either worked inone piece, or the hollow body may be fitted to the edge of the jacketi n any desired manner, e.g. fastening by means of an adhesive tape would already do. The forwardly converging sleeve may be of frusto-conical shape, or of conical shape, i.e. closed at its forward end; The shape of the tapered end may be flat, concave or convex. Similar to practises used in connection with shaped charges, theblasting effect may still be increased by fixing to the front face of the explosive charge a lining of easily deformable mel't'able or evaporable metal. I

Surprisingly it has beer'r found that the arrangement which has been broadly described above, is capable of giving particularly good results if certain dimeiisio'rial' and shape limitations with respect to the sleeve in' relation to the charge are maintained. v

Thus, according to the preferred embodiment of the present invention, the generatrix of the sleeve forms with the axis of the same an angle of between 5 and 14. In other words, the apex angle of the converging sleeve is preferably between 10 and 28.,,, Furthermore, and particularly with respect to explosive charges having a fiat circular front face, it is desirable and givesjfar, superior results if the heig ht, of the sleeve, i.e. the distance from the front face, of the explosive, charge to the apex of the convergingsleeve, measured in a direction perpendicular to the plane of the front face of the explosive charge, equals between ,1.8 and 5 times the diameter of the fiat front face of the explosive charge. While. the, sleeve is illustrated and described herein mainly as being of conical or frusto-conical shape, this is not to be considered an absolute limitation. The generatrix of the sleeve may also be of parabolic or bottle neck-shaped curved configuration, but it is preferred that the overall inclination will be within the above-desclibed'range.

Furthermore, it has been found to be particularly advantageous to provide the sleeve at its narrower and poi" tion with an opening having a diameter equal to up to 25, preferably between 0% and 15% of the diameter of the hat front face of the explosive charge. These preferred dimensions include a conical sleeve which terminates in a pointed end portion without an opening therein.

The sleeve may be made of any desired material such as metal, wood, synthetic materials, mill-board and the like, whereby, sleeves of lead have been found to give particularly good results. The wall thickness of the sleeve will depend on the strength and. the specific gravity of the material of which the sleeve'is formed. Inv other words, the higher the strength and the specific gravity of the sleeve forming'material, the smaller may be the wall thickness of thesleeve.

The novel features which are considered as characteris-. tic for the invention are set forth in particular in the appended claims. The invention itself, however; both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a schematic elevational view of a demolition arrangement according to the present invention wherein the sleeve is of frusto-conical shape;

FIG. 2 is a schematic elevational cross-sectional view of another demolition arrangement according to the present invention wherein the sleeve forms a conical cavity.

In all figures of the drawing, the explosive charge is indicated by reference numeral 1, the jacket covering the explosive charge with the exception of its front face 2 is indicated by reference numeral 6, and a liner 16 may be fitted to front face 2. Reference numeral 5 indicates the detonator. The charge may be of any conventional shape and may be produced of conventional explosive compositions. The experiments which will be described further below were carried out with a charge having a funnel-shaped configuration. The front face 2 of the charge 1 which front face is not covered in this case by a liner is of planar configuration. Guide sleeve 3 is arranged surrounding front face 2 of charge l and converging towards target 4. The experiments described below were carried out with charges having a circular planar face 2 with a diameter of 45 or 50 mm. The effect of varying the angle alpha between the axis and the generatrix of the sleeve, as well as the effect of varying the height or length h of the sleeve and the diameter of the forward opening d are described in the tables further below.

Before discussing the advantageous effect of the specific configurational limitation of the demolition arrangement according to the present invention, the following Examples 14 will serve to broadly illustrate the effect of forwardly converging sleeve arrangements, without, however, limiting the invention to any of the specific details of the examples.

Example 1 Substantially as illustrated, an explosive composition, consisting of trinitrotoluene-RDX 40:60 was cast into a metal container. The weight of charge amounted to 75 g. The diameter of the explosive body was 50 mm. at

its greatest width. The conical sleeve was fixed with adhesive tape. The charge thus prepared for blasting was arranged in front of the iron plate to be perforated at a distance of 15 mm. An iron plate of 8 mm. thickness was used for this example. After the explosion, the plate showed a punched hole of 40 mm. inner diameter, whereas a comparative blasting without the conical sleeve only resulted in a bulge-like deformation of the plate.

Example 2 Example 3 An explosive charge equal to that used for Example 2 was prepared. An iron sleeve homogeneously leaded, was used. The conical sleeve, covered with a lead lining, was fixed with an adhesive tape and placed onto the plate to be perforated. After the explosion, the plate showed a similar crater-like hollow, as described above, the hollow being larger than that obtained with ordinary iron sleeves.

Example 4 An explosive composition of 48 g., consisting of trinitrotoluene-RDX 50:50, was cast into a metal container.

The diameter of the explosive charge was 45 mm. at its greatest width. A conical sleeve of sheet iron of 0.5 mm. thickness, which was open at both ends and had a taper of 35 mm. height forming an angle of with respect to the axis, was attached to the explosive charge by adhesive tape; the explosive body thus prepared was placed with its tapered end onto a steel plate of 15 mm. thickness. After the explosion, the steel plate showed a punched hole of about 25 mm. diameter.

When using a conical sleeve of the same material, having a hei ht of 52 mm. and forming an angle of 15 with respect to the axis, a hole of about mm. diameter was obtained in a steel plate of 15 mm. thickness with the same explosive charge. A sleeve of 80 mm. height with an angle of 10 with respect to the axis, which was attached to the same explosive charge, punched a hole of about 32 mm. diameter into the steel plate of 15 mm. thickness.

Further experiments which will serve to illustrate the particular advantages of limiting the apex angle and the height of the sleeve in accordance with the present invention, are summarized in the tables further below.

The experiments which are thus summarized were carried out with explosive charges weighing grams and consisting of a mixture of equal parts of trinitrotoluene and RDX, i.e., cyclotrimethylenetrinitramine. The charge, with the exception of its planar front face was covered with a jacket consisting of a steel sheet of 0.8 mm. thickness. The sleeve in each of these experiments consisting of bright drawn steel 11. The sleeve was attached to the jacket surrounding the charge in the position illustrated in the drawing. The top of the sleeve was positioned in all experiments in direct contact with a steel plate of 50 mm. thickness which served as the object to be subjected to destruction by the explosive charge.

The first column of each of the tables indicates the test number within the series of tests summarized in the respective table, columns 2, 3 and 4 respectively give the values for the angle alpha between generatrix and axis of the sleeve, the height h of the guide sleeve and the diameter d of the opening in the forward end of the guide sleeve which contacts steel plate 4. Column 5 indicates in millimeters the depth of the indentation in the steel plate which was formed by detonating the charge under the conditions indicated in the respective tests.

Table I summarizes tests which were made with a guide sleeve formed of a steel sheet of 1 mm. thickness and having at its apex an opening of 4.8 mm. diameter. The variables in this series are the angle between the axis and the generatrix of the frusto-conical sleeve and correspondingly the height h of the sleeve.

It will be seen that maximum effect was achieved in test 9 with a depth of the indentation of 32 mm. This was accomplished at an angle of 6.8".

TABLE I Test No. 04 IL/mrn. d/mm. T/nun.

Tables II and III show the results which were achieved with steel sleeves having a wall thickness of 5 and 10 mm. respectively. It will be seen that optimum results. again are obtained in test 9, i.e. at an angle of 6.8".

TABLE H [Sleeve wall thiclmess 1 m.]

1 2 3 4 5 Test No. 04 h/mm. d/mm. T/mrn.

TABLE III [Sleeve wall thickness 111111.] 7

a h/mm d/mm. T/nnn.

The tests which are summarized in Table IV were carried out with a conical guide sleeve according to FIG. 2 which was formed of a steel of 10 mm. thickness. It will be seen that best results in this case are achieved at an angle of 9.8 which is different from the angle which gives best results with the guide sleeve according to FIG. 1.

Table V illustrates how the diameter d will influence the results obtained under otherwise equal conditions. The angle between the axis and the generatrix of the sleeve varies corresponding to the change in the diameter of opening d while the height of the sleeve remains unchanged. It can be seen that the smaller opening d gives a far superior result.

TABLE V Test No. a h/mm. d/mm. T/mm.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of demolition arrangement difie'ringfrom the types described above.

While the invention has been illustrated and described as embodied in explosive demolition device, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A stationary demolition arrangement, comprising, in combination, an object to be subjected to explosive force; an explosive device including an explosive charge having a substantially fiat front face spaced from and directed toward the surface of said object so that upon detonation the exploding charge will emanate from said front face toward said object; and a guide sleeve interposed at least between said explosive device and said object, said guide sleeve substantially surrounding said front face of said explosive charge and having an axis substantially perpendicular to said flat front face of said explosive charge, said guide sleeve converging in the direction towards said object at an angle of between about 6 and 11 between said axis and the generatrix of said guide sleeve so as to limit the lateral expansion of the exploding charge and concentrate the same toward the surface of said object.

2. A stationary demolition arrangement, comprising, in combination, an object to be subjected. to explosive force; an explosive device including an explosive charge having a substantially flat free front face spaced from and directed toward the surface of said object so that upon detonation the exploding charge will emanate from said front face toward said object; and a guide sleeve contact,- ing, and interposed between, said explosive device and said object, said guide sleeve substantially surrounding said front face of said explosive charge and having an axis substantially perpendicular to said fiat front face of said explosive charge, said guide sleeve converging in the direction towards said object at an angle of between about 6 and 11 between said axisjand the generatrix of said guide sleeve so as to limit the lateral expansion of the exploding charge and concentrate the same toward the surface of said object. 7

3. A stationary demolition arrangement, comprising, in combination,- an object to be subjected to explosive force; an explosive device including an explosive charge having asubstantially flat free front face which latter is spaced from and directed toward the surface of said ob.- ject so that upon detonation the exploding charge will emanate from said front face toward said object; and a substantially frusto-conical guide sleeve interposed at least between said explosive device and said object, said guide sleeve substantially surrounding said frontface of said explosive charge and having an axis substantially perpendicular to said flat front face of said explosive charge, said guide sleeve converging in the direction towards said object at an angle of between about 6 and 11 between said axis and the generatrix of said guide sleeve so as to limit the lateral expansion of the exploding charge and concentrate the same toward the surface of said object.

4. A stationary demolition arrangement, comprising, in combination, an object to be subjected to explosive force; an explosive device including an explosive charge having a substantially flat front face which is fitted with a liner and spaced from and directed toward the surface of said object so that upon detonation the exploding charge will emanate from said front face toward said object; and a substantially frusto-conical guide sleeve interiposed at least between said explosive device and said object, said guide sleeve substantially surrounding said front face of said explosive charge and having an axis substantially perpendicular to said flat front face of said explosive charge, said guide sleeve converging in the direction towards said object at an angle of between about 6 and 11 between said axis and the generatrix of said guide sleeve so as to limit the lateral expansion of the exploding charge and concentrate the same toward the surface of said object.

5. A stationary demolition arrangement, comprising, in combination, an object to be subjected to explosive force; an explosive device including an explosive charge having a substantially flat front face which is spaced from and directed toward the surface of said object so that upon detonation the exploding charge will emanate from said front face toward said object; and a substantially frusto-conical guide sleeve interposed at least between said explosive device and said object, said guide sleeve substantially surrounding said front face of said explosive charge and having an axis substantially perpendicular to said flat front face of said explosive charge, said guide sleeve converging in the direction towards said object at an angle of between about 5.0 and 9.l between said axis and the generatrix of said frusto-conical sleeve so as to limit the lateral expansion of the exploding charge and concentrate the same toward the surface of said object.

6. A stationary demolition arrangement, comprising, in combination, an object to be subjected to explosive force; an explosive device including an explosive charge having a substantially flat substantially circular front face which is spaced from and directed toward the surface of said object so that upon detonation the exploding charge will emanate from said front face toward said object, and a substantially frusto-conical guide sleeve interposed at least between said explosive device and said object, said guide sleeve substantially surrounding said front face of said explosive charge and having an axis substantially perpendicular to said circular fiat front face of said explosive charge passing through the center of the same, said guide sleeve converging in the direction towards said object at an angle of between about 6 and 11 between said axis and the generatrix of said frusto-conical sleeve so as to limit the lateral expansion of the exploding charge and concentrate the same toward the surface of said object.

7. A stationary demolition arrangement, comprising, in combination, an object to be subjected to explosive force; an explosive device including an explosive charge having a substantially flat, substantially circular, front face, of which is spaced from and directed toward the surface of said object so that upon detonation the exploding charge will emanate from said front face toward said object; and a substantially frusto-conical guide sleeve interposed at least between said explosive device and said object, said guide sleeve substantially surrounding said circular fiat front face of said explosive charge and having an axis extending perpendicular to said circular flat front face from the center of the same, said guide sleeve converging in the direction toward said object at an angle in the region of 6.8 between the axis and the generatrix of said frusto-conical sleeve and extending forward of said front face for a distance, measured in axial direction of said guide sleeve, equal to between 1.8 times and 5 times the diameter of said circular front face so that said converging guide sleeve will limit the lateral expansion of the exploding charge and concentrate the same in forward direction.

8. A stationary demolition arrangement, comprising, in combination, an object to be subjected to explosive force; an explosive device including an explosive charge having a substantially flat, substantially circular, front face which is spaced from and directed toward the surface of said object so that upon detonation the exploding charge will emanate from said front face toward said object; and a substantially frusto-conical guide sleeve interposed at least between said explosive device and said object, said guide sleeve substantially surrounding said circular fiat front face of said explosive charge and having an axis extending perpendicular to said circular flat front face from the center of the same, said guide sleeve converging in the direction toward said object at an angle in the region of 6.8 between the axis and the generatrix of said frusto-conical sleeve and extending forward of said front face for a distance, measured in axial direction of said guide sleeve, equalto between 1.8 times and 5 times the diameter of said circular front face, the inner diameter of the forward end portion of said frusto-conical guide sleeve being equal to up to 25% of the diameter of said circular front face of said explosive charge so that said converging guide sleeve will limit the lateral expansion of the exploding charge and concentrate the same in forward direction.

9. A stationary explosive demolition device, comprising, in combination, an explosive charge being enclosed in a jacket and having a fiat front face so that upon detonation the exploding charge will emanate from said front face toward an object to be subjected to explosive force; and a guide sleeve connected to said jacket and extending forwardly of said explosive charge substantially surrounding said front face thereof and substantially coaxial with the same, said guide sleeve converging in forward direction at an angle of between 6 and 11 between its axis and its generatrix and extending forwardly of said front face of said explosive charge for a distance equal to between 1.8 times and 5 times the largest diameter of said front face of said explosive charge so that said converging guide sleeve will limit the lateral expansion of the exploding charge and concentrate the same in forward direction.

10. A stationary explosive demolition device, comprising, in combination, an explosive charge being enclosed in a jacket and having a flat substantially circular front face so that upon detonation the exploding charge will emanate from said front face toward an object to be subjected to explosive force; and a substantially frustoconical guide sleeve connected to said jacket and extending forwardly of said explosive charge substantially surrounding said front face thereof and substantially coaxial with the same, said guide sleeve converging in forward direction at an angle in the region of 68 between its axis and its generatrix and extending forwardly of said front face of said explosive charge for a distance equal to between 1.8 times and 5 times the diameter of said circular front face of said explosive charge, the forward end portion of said guide sleeve have an inner diameter equal to between 0% and 15% of the diameter of said circular front face of said explosive charge, so that said converging guide sleeve will limit the lateral expansion of the exploding charge and concentrate the same in forward direction.

11. A stationary demolition arrangement, comprising, in combination, an object to be subjected to explosive force; an explosive device including an explosive charge having a substantially fiat front face which is spaced from and directed toward the surface of said object so that upon detonation the exploding charge will emanate from said front face toward said object; and a conical guide sleeve interposed at least between said explosive device and said object, said guide sleeve substantially surrounding said front face of said explosive charge and having an axis substantially perpendicular to said flat front face of said explosive charge, said guide sleeve converging in the direction towards said object at an angle in the region of 9.8 between said axis and the generatrix of said conical sleeve so as to limit the lateral expansion of the exploding charge and concentrate the same toward the surface of said object.

12. A stationary demolition arrangement, comprising, in combination, an object to be subjected to explosive force; an explosive device including an explosive charge having a substantially fiat, substantially circular, front face, which is spaced from and directed toward the surface of said object so that upon detonation the exploding charge will emanate from said front face toward said object; and a conical guide sleeve interposed at least between said explosive device and said object, said guide sleeve substantially surrounding said circular flat front face of said explosive charge and having an axis extending perpendicular to said circular flat front face from the center of the same, said guide sleeve converging in the direction toward said object at an angle of between 6 and 11 between the axis and the generatrix of said conical sleeve and extending forward of said front face for a distance, measured in axial direction of said guide sleeve, equal to between 1.8 times and 5 times the diameter of said circular front face so that said converging guide sleeve will limit the lateral expansion of the exploding charge and concentrate the same in forward direction.

13. A stationary demolition arrangement, comprising, in combination, an object to be subjected to explosive force; an explosive device including an explosive charge having a substantially flat, substantially circular, front face, which 'is spaced from and directed toward the surface of said object so that upon detonation the exploding charge will emanate from said front face toward said object; and a substantially frusto-conical guide sleeve interposed at least between said explosive device and said object, said guide sleeve substantially surrounding said circular flat front face of said explosive charge and having an axis extending perpendicular to said circular flat front face from the center of the same, said guide sleeve converging in the direction toward said object at an angle in the region 6.8 between the axis and the generatrix of said frusto-conical sleeve and extending forward of said front face for a distance, measured in axial direction of said guide sleeve, equal to between 1.8 times and 5 times the diameter of said circular front face, the inner diameter of the forward end portion of said frustoconical guide sleeve being equal to between 0% and 15% of the diameter of said circular front face of said explosive charge so that said converging guide sleeve will limit the lateral expansion of the exploding charge and concentrate the same in forward direction.

References Cited in the file of this patent UNITED STATES PATENTS 2,359,301 Church et a1. Oct. 3, 1944 2,419,414 Mohaupt Apr. 22, 1947 2,521,739 Meister Sept. 12, 1950 2,605,703 Lawson Aug. 5, 1952 2,679,380 Sweetman May 25, 1954 FOREIGN PATENTS 645,611 Great Britain Nov. 1, 1950

Claims

1. A STATIONARY DEMOLITION ARRANGEMENT, COMPRISING, IN COMBINATION, AN OBJECT TO BE SUBJECTED TO EXPLOSIVE FORCE; AN EXPLOSIVE DEVICE INCLUDING AN EXPLOSIVE CHARGE HAVING A SUBSTANTIALLY FLAT FRONT FACE SPACED FROM AND DIRECTED TOWARD THE SURFACE OF SAID OBJECT SO THAT UPON DETONATION THE EXPLODING CHARGE WILL EMANATE FROM SAID FRONT FACE TOWARD SAID OBJECT; AND A GUIDE SLEEVE INTERPOSED AT LEAST BETWEEN SAID EXPLOSIVE DEVICE AND SAID OBJECT, SAID GUIDE SLEEVE SUBSTANTIALLY SURROUNDING SAID FRONT FACE OF SAID EXPLOSIVE CHARGE AND HAVING AN AXIS SUBSTANTIALLY PERPENDICULAR TO SAID FLAT FRONT FACE OF SAID EXPLOSIVE CHARGE, SAID GUIDE SLEEVE CONVERGING IN THE DIRECTION TOWARDS SAID OBJECT AT AN ANGLE OF BETWEEN ABOUT 6 AND 11* BETWEEN SAID AXIS AND THE GENERATRIX OF SAID GUIDE SLEEVE SO AS TO LIMIT THE LATERAL EXPANSION OF THE EXPLODING CHARGE AND CONCENTRATE THE SAME TOWARD THE SURFACE OF SAID OBJECT.