Explosive Charge with Longitudinal Grooves for Directed Fragmentation
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Solution Overview
Problem
Existing explosive charges, such as the Bangalore Torpedo, are cumbersome for cutting small obstacles, have limited range due to scaling issues, and pose safety hazards from sharp metal fragments, and are ineffective against modern, harder wire fences.
Innovation Solution
A compact, tubular metal charge with concave wall sections forming longitudinal grooves that produce directed, elongate projectiles upon detonation, enhancing cutting efficiency and range while reducing fragment disintegration and operator risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the length of the unit charge is increased to extend cutting range, then the cutting range is improved, but the charge becomes awkward to carry and unnecessarily large for small obstacles
Solution Approach 1:
The charge is divided into multiple unit charges that can be connected end-to-end using bayonet fittings or screw threads. Each unit charge is compact and portable, but they can be assembled into longer arrays to extend the cutting range when needed, resolving the contradiction between portability and cutting range.
2Length of stationary object
If the diameter of the charge is doubled to double the wire severing range, then the blast range is improved, but the explosive load increases four-fold
Solution Approach 1:
Instead of increasing diameter (two-dimensional scaling), the invention extends the charge in the length dimension by connecting multiple unit charges end-to-end. This linear scaling approach increases blast range without the exponential increase in explosive load that would result from diameter doubling.
3Strength
If the wall thickness is increased to produce sharper fragments for cutting, then the fragment sharpness is improved, but the fragment weight increases and range is reduced
Solution Approach 1:
The invention changes the geometric parameters of the fragment-producing structure by introducing longitudinal grooves and concave wall sections. This modifies the fragmentation pattern to produce elongate, rod-like projectiles with optimal sharpness-to-weight ratio, maintaining cutting effectiveness while extending range compared to simple cylindrical tubes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables effective cutting of wire obstacles at greater distances with reduced energy consumption and enhanced safety by producing coherent, high-velocity projectiles that maintain cutting power over longer ranges and minimize hazards to the operator.
Implementation Method 1
the charge depends for its effectiveness upon the blast effect of the explosive it contains
Implementation Method 2
the advancing detonation wave front progressively collapses a metal-lined cavity
Implementation Method 3
the wall of the tube is provided with one or more concave wall sections forming longitudinal grooves that produce directed, elongate projectiles upon detonation
Implementation Method 4
The effect is enhanced by the impact of fragments of the tubular case which are projected at high velocity in radial directions
Data Source
AI summary
Container (10) is generally cylindrical except for a longitudinal concave groove (11) extending along its entire length. Upon explosion, the contour of this groove (11) results in a focussing effect on the wall material due to the oblique angle at which the expanding cylindrical detonation wave front impacts upon its inner wall. This produces the forging of a rough rod-like projectile (111) which, being coherent, maintains its velocity and consequently travels much further than the randomly shaped projectiles (101).