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US3613581A Expired / Lapsed US ⏱️ 0.0 years remaining

Explosive device for perforating high-strength metal plates

Assignee: United States Department of the Navy
•
Filing: 1964-11-20
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Granted: 1971-10-19
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Expires: 1984-11-20
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Abstract

Abstract 1. An explosive device for removing a circular pluglike fragment from a metal plate structure, comprising; A. CYLINDRICAL METAL OUTER CASING TUBE HAVING FRONT AND REAR ENDS AND CONTAINING A CHARGE OF EXPLOSIVE MATERIAL, B. SAID CHARGE HAVING A FIRST, CYLINDRICAL, AXIAL PORTION IN CIRCUMFERENTIAL CONTACT WITH THE INNER SURFACE OF THE WALL OF SAID TUBE AND EXTENDING FORWARDLY TO A CIRCULAR FORWARD LIMIT OF EXPLOSIVE CHARGE AND TUBE CONTACT, AND HAVING A SECOND, FRONT END, AXIAL PORTION ADJOINING AND EXTENDING FORWARDLY FROM SAID CIRCULAR FORWARD LIMIT AND TERMINATING AT ITS FORWARDMOST PORTION AT AN AXIAL POSITION SUBSTANTIALLY COADJACENT THE FRONT END OF THE TUBE, SAID FRONT END AXIAL PORTION FORMING AN AXIALLY ALIGNED FORWARDLY CONVERGING BODY OF REVOLUTION HAVING ITS OUTER SURFACE IN RADIALLY SPACED RELATIONSHIP TO THE WALL OF THE TUBE DEFINING AN ANNULAR CAVITY THEREABOUT BETWEEN THE BARE OUTER SURFACE OF THE EXPLOSIVE MATERIAL AND THE INNER SURFACE OF THE WALL OF SAID TUBE, SAID ANNULAR CAVITY BEING OF FORWARDLY INCREASING CROSS SECTION FORMING AN EXPLOSIVE PRESSURE FOCUSING CAVITY FOR CONCENTRATING THE INITIAL EXPLOSIVE EFFECT IN AXIALLY FORWARDLY AND LATERALLY OUTWARD DIRECTIONS TO PRODUCE A SEMITOROIDAL CRATER HAVING A MEDIAN CRATER DIAMETER APPROXIMATELY COEXTENSIVE WITH THE DIAMETER OF THE TUBE IN THE SURFACE OF A METAL TARGET PLATE DISPOSED ADJACENTLY AND NORMALLY TO THE FRONT END OF THE TUBE AT THE TIME THE CHARGE IS EXPLODED, C. SAID CHARGE BEING MADE OF AN EXPLOSIVE MATERIAL OF SUCH A CHARACTER THAT IT PRODUCES A TIME DISTRIBUTION OF DYNAMIC EXPLOSIVE LOADING EFFECTS BY WHICH THE HIGH LEVEL OF EXPLOSIVE LOADING IS SUSTAINED MOMENTARILY AFTER FORMATION OF THE SEMITOROIDAL CRATER TO PRODUCE A PUNCHLIKE EXPLOSIVE LOADING UPON THE SURFACE OF THE TARGET PLATE ENCIRCLED BY THE CRATER TENDING TO CAUSE AN APPROXIMATELY FRUSTOCONICAL FRACTURE SURFACE EXTENDING FROM THE BOTTOM OF THE CRATER TO THE OPPOSITE SIDE OF THE PLATE AND DIVERGENT IN THE DIRECTION TOWARD SAID OPPOSITE SIDE, WHEREUPON THE PORTION OF THE PLATE ENCOMPASSED BY THE CRATER AND FRACTURE SURFACE IS REMOVED FROM THE BODY OF THE PLATE.

Inventors

  • 👤 William B Mclean
  • 👤 Lawrence N Cosner
  • 👤 John Pearson

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-07 18:54
CPC Classifications
F; F42; F42B; F42B3/00; F42D; F42D3/00

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 338 words
An explosive device for removing a circular pluglike fragment from a metal plate structure, comprising; a. cylindrical metal outer casing tube having front and rear ends and containing a charge of explosive material, b. said charge having a first, cylindrical, axial portion in circumferential contact with the inner surface of the wall of said tube and extending forwardly to a circular forward limit of explosive charge and tube contact, and having a second, front end, axial portion adjoining and extending forwardly from said circular forward limit and terminating at its forwardmost portion at an axial position substantially coadjacent the front end of the tube, said front end axial portion forming an axially aligned forwardly converging body of revolution having its outer surface in radially spaced relationship to the wall of the tube defining an annular cavity thereabout between the bare outer surface of the explosive material and the inner surface of the wall of said tube, said annular cavity being of forwardly increasing cross section forming an explosive pressure focusing cavity for concentrating the initial explosive effect in axially forwardly and laterally outward directions to produce a semitoroidal crater having a median crater diameter approximately coextensive with the diameter of the tube in the surface of a metal target plate disposed adjacently and normally to the front end of the tube at the time the charge is exploded. c. said charge being made of an explosive material of such a character that it produces a time distribution of dynamic explosive loading effects by which the high level of explosive loading is sustained momentarily after formation of the semitoroidal crater to produce a punchlike explosive loading upon the surface of the target plate encircled by the crater tending to cause an approximately frustoconical fracture surface extending from the bottom of the crater to the opposite side of the plate and divergent in the direction toward said opposite side, whereupon the portion of the plate encompassed by the crater and fracture surface is removed from the body of the plate.
Claim 2
Dependent Claim 338 words
An explosive device for removing a circular pluglike fragment from a metal plate structure, comprising; a. cylindrical metal outer casing tube having front and rear ends and containing a charge of explosive material, b. said charge having a first, cylindrical, axial portion in circumferential contact with the inner surface of the wall of said tube and extending forwardly to a circular forward limit of explosive charge and tube contact, and having a second, front end, axial portion adjoining and extending forwardly from said circular forward limit and terminating at its forwardmost portion at an axial position substantially coadjacent the front end of the tube, said front end axial portion forming an axially aligned forwardly converging body of revolution having its outer surface in radially spaced relationship to the wall of the tube defining an annular cavity thereabout between the bare outer surface of the explosive material and the inner surface of the wall of said tube, said annular cavity being of forwardly increasing cross section forming an explosive pressure focusing cavity for concentrating the initial explosive effect in axially forwardly and laterally outward directions to produce a semitoroidal crater having a median crater diameter approximately coextensive with the diameter of the tube in the surface of a metal target plate disposed adjacently and normally to the front end of the tube at the time the charge is exploded. c. said charge being made of an explosive material of such a character that it produces a time distribution of dynamic explosive loading effects by which the high level of explosive loading is sustained momentarily after formation of the semitoroidal crater to produce a punchlike explosive loading upon the surface of the target plate encircled by the crater tending to cause an approximately frustoconical fracture surface extending from the bottom of the crater to the opposite side of the plate and divergent in the direction toward said opposite side, whereupon the portion of the plate encompassed by the crater and fracture surface is removed from the body of the plate.
Claim 3
Dependent Claim 18 words
A device in accordance with claim 1, wherein said charge is made of a composition C-type explosive material.
Claim 4
Dependent Claim 22 words
A device in accordance with (12) claim 1, e. said body of revolution, at its forwardmost end, having a substantial cross-sectional area.
Claim 5
Dependent Claim 79 words
A device in accordance with claim 3 and further for delivering a follow-through projectile through the perforation left in the plate structure, said device further comprising; f. said body of revolution having formed therein an axial bore for containing a follow-through projectile for delivery through the perforation in the metal plate under force of explosion, said bore at its front end forming a central opening in said substantial cross-sectional area, and g. a follow-through projectile disposed in said bore.
Claim 6
Dependent Claim 21 words
A device in accordance with claim 1, and h. said body of revolution forming a sharp tip at its forwardmost end.

References Cited (Backward Citations)

USRE23211E Cited
FR1231003A Cited
US3117518A Cited
US2988994A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1974-10-18 1975-04-19 1975-10-19 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1978-10-18 1979-04-19 1979-10-19 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1982-10-18 1983-04-19 1983-10-19 $7700.00 Window Closed / Lapsed

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