Shaped charge and method of making it

• US 4,450,768 A
• Filed: 03/25/1983
• Issued: 05/29/1984
• Est. Priority Date: 01/12/1981
• Status: Expired due to Term

• Current Assignee: Schlumberger Technologies Incorporated (SLB)
• Original Assignee: Schlumberger Technologies Incorporated (SLB)
• Inventors: Bell, William T.
• Primary Examiner(s): Sebastian, Leland A.
• Application Number:
  US06/479,063
• Time in Patent Office: 431 Days
• Field of Search: 86/1 R, 86/20 R, 86/20 B, 86/20 V, 102/306, 102/307, 102/310, 175/4.6, 264/3 R
• US Class Current: 102/307
• CPC Class Codes: F42B 1/036 Manufacturing processes therefor F42B33/0214 - F42B33/0292 take precedence

Abstract

The detonating bore in the rear wall of a shaped charge case is outwardly convex. A powdered explosive is compacted into the case through the open front opposite the detonating bore, causing the portion which enters the convex end of the bore from within the case to be less compacted and less dense, for increased sensitivity and more reliable detonation.

Claims

1. A method for fabricating a shaped charge, comprising:

(a) forming a hollow case having a rear wall and an open end opposite the rear wall,

(b) forming a detonating bore in the rear wall of the hollow case,

(c) forming an outwardly convex end in the detonating bore,

(d) loading explosive powder material into the case substantially only through the open end thereof, and

(e) compacting the explosive material within the case into a shaped charge, through the open end thereof and toward and against the rear wall thereof, to cause a portion of the explosive to enter the detonating bore and the convex end thereof and be less compacted and less dense in the convex end than in substantially the remainder of the explosive within the hollow case, for increased sensitivity and better and more reliable detonation of the shaped charge.

2. The method of claim 1 further comprising forming an essentially conical convexity.

3. The method of claim 1 further comprising forming the detonating bore entirely through the rear wall of the hollow case.

4. A method for fabricating a shaped charge, comprising:

(a) forming a hollow case having a rear wall and an open end opposite the rear wall,

(b) forming a detonating bore through the rear wall of the hollow case,

(c) forming a conical, outwardly convex end in the detonating bore,

(d) loading explosive powder material into the case substantially only through the open end thereof, and

(e) compacting the explosive material within the case into a shaped charge, through the open end thereof and toward and against the rear wall thereof, to cause a portion of the explosive to enter the detonating bore and the convex end thereof and be less compacted and less dense in the convex end than in substantially the remainder of the explosive within the hollow case, for increased sensitivity and better and more reliable detonation of the shaped charge.

5. A method for fabricating a shaped charge, comprising:

(a) forming a charge casing having side wall portions and a rear wall portion defining an inner cavity with a frontal opening therein,

(b) forming a detonating bore through the rear wall portion including decreasing the cross-sectional area of the portions of the detonating bore proximate to the inner cavity,

(c) loading explosive material into the inner cavity of the casing through the frontal opening.

(d) compacting the explosive material through the frontal opening and toward the rear wall portion thereby defining a shaped charge adjacent the rear wall portion while simultaneously introducing a portion of the explosive material into the detonating bore and beyond the portion of the detonating bore having the decreased cross-sectional area thereby affording an increased area for the explosive material, and

(e) at least partially diffusing the explosive material within the increased area so as to lessen the density of the explosive material therein thereby increasing the sensitivity of the shaped charge.

6. The method for fabricating a shaped charge as claimed in claim 5 wherein said forming a detonating bore through said rear wall portion includes gradually decreasing the cross-sectional area of the portions of the detonating bore proximate the inner cavity so as to define a substantially conical tapering along the bore.

7. A shaped charge, comprising:

a charge casing having side wall portions and a rear wall portion defining an inner cavity with a frontal opening therein,

wall portions defining a detonating bore through said rear wall portion wherein said bore has a decreasing cross-sectional area proximate to said inner cavity,

whereby the loading of explosive material into said inner cavity through said frontal opening and the compacting of the explosive material through said frontal opening and toward said rear wall portion will define a compacted portion of explosive material adjacent said rear wall portion while simultaneously introducing a portion of the explosive material into said detonating bore and beyond said portion of said detonating bore having the decreased cross-sectional area, and whereby the increased area for the explosive material will result in at least a partial dispersion of the explosive material so as to lessen the density of the explosive material therein and thereby increase the sensitivity of the shaped charge.

8. A shaped charge as claimed in claim 7 wherein said detonating bore through said rear wall portion includes a gradually decreasing cross-sectional area proximate the inner cavity so as to define a substantially conical tapering along the portion of said bore proximate said cavity.