Slotted Deformable Bullet Intermediate for Controlled Expansion
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Solution Overview
Problem
Existing methods for manufacturing deformable bullets with unfilled cavities in the ogive region face issues such as clogging by harder materials, leading to suboptimal deformation behavior, and tools used in deep-drawing processes tend to break easily and result in uneven deformation due to stress variations.
Innovation Solution
A deformable bullet intermediate is created using a ductile cylindrical base body made of lead-free materials, cold-formed with a stamp-die arrangement featuring radial slots that form prongs to create a slotted wall, allowing for controlled deformation and preventing tool breakage, while maintaining a partially open cavity for hydraulic pressure buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large ogive tip opening is used to allow gelatinous mass penetration, then deformation behavior is improved, but the opening gets clogged by harder materials preventing penetration
Solution Approach 1:
The ogive wall is segmented into multiple prongs separated by radial slots instead of forming a continuous wall. This segmentation allows the prongs to deform independently upon impact, preventing the clogging issue while maintaining reliable deformation behavior. The slots create discrete pathways that guide the deformation process without allowing material buildup to block the entire opening.
Solution Approach 2:
The solution transitions from a two-dimensional wall surface to a three-dimensional prong structure with radial slots. This dimensional change creates depth and volume in the ogive region, allowing hydraulic pressure to build up effectively while maintaining open pathways for gelatinous mass penetration through the slot configurations.
2Ease of manufacture
If conventional deep-drawing tools with cone-shaped or pyramidal structures are used, then intermediate formation is achieved, but the tools break easily and service life is low
Solution Approach 1:
Instead of using a cone-shaped or pyramidal mandrel that pushes material outward (conventional approach), the invention uses a stamp with a complementary negative profile that forms the intermediate by pressing material into shape. This inversion of the forming approach eliminates the stress concentrations that cause tool breakage in conventional deep-drawing methods.
Solution Approach 2:
The forming process parameters are changed from high-stress deep-drawing with sharp corners to controlled stamping with optimized contact surfaces. The stamp design distributes pressure more evenly across the material, reducing peak stresses that lead to tool failure and extending service life while still achieving the desired intermediate geometry.
3Ease of manufacture
If cone-shaped or pyramidal mandrels are used for cold-forming, then intermediate shape is created, but stress variations cause uneven deformation and low controllability
Solution Approach 1:
The stamp design incorporates locally optimized contact surfaces and pressure distribution zones tailored to specific regions of the intermediate. Different areas of the stamp apply different pressures and forces to achieve uniform deformation throughout the material, preventing the uneven deformation caused by conventional mandrels. The radial slots are strategically positioned to ensure consistent stress distribution during forming.
4Reliability
If through slotting is used to create radial passages, then deformation control is improved, but the wall structure becomes weaker
Solution Approach 1:
The wall is divided into multiple prongs through radial slotting, which actually strengthens the overall structure by creating load-bearing segments. Each prong acts as an independent load-bearing element, and the segmentation allows for controlled deformation while maintaining sufficient strength. The slots are optimized in number, position, and width to balance deformation control requirements with structural strength needs.
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 optimized deformation behavior upon impact, avoiding clogging and tool failure, and allows for the production of bullets with desired partial fragmentation characteristics without splintering, using a cold-forming process that eliminates the need for machining.
Implementation Method 1
The base body or blank to be formed to the intermediate forms as an intermediate a cylindrical, solid base end section... Furthermore, the intermediate comprises a press end section, which is diametrically opposite to the base end section in the axial direction of the projectile, wherein the press end section is formed with a central press recess incorporated by means of the pressing process
Implementation Method 2
A deformable bullet intermediate is created using a ductile cylindrical base body made of lead-free materials, cold-formed with a stamp-die arrangement featuring radial slots that form prongs
Implementation Method 3
which, when hitting the gelatinous mass, cause a mushroom-shaped or sepal-shaped deformation of the wall bent radially outwards... the gelatinous mass, which builds up the hydraulic pressure, cannot penetrate into the cavity
Implementation Method 4
optimized deformation behavior upon impact... allows for the production of bullets with desired partial fragmentation characteristics
Data Source
AI summary
Intermediate for the production of a projectile in particular a deformable bullet, consisting of a ductile blank, which is cold-formed into the intermediate by means of pressing, a cylindrical solid base end section and a press end section with a central press recess incorporated by means of pressing and a wall limiting the press recess to form an ogival shaped tip, wherein the wall is formed with at least two slots extending in the axial direction of the intermediate, which separate at least two prongs in the circumferential direction of the intermediate, wherein the at least two slots extend by more than 10% of an axial total longitudinal extension of the intermediate from the wall end towards the base end section.