Biodegradable Wad with Cup Seal for Rifle Cartridge

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Solution Overview

Problem

Current ammunition cartridges made from synthetic materials contribute significantly to environmental pollution due to non-biodegradable components that persist in nature, causing harm to wildlife and ecosystems, and existing biodegradable alternatives either fail to decompose effectively or are too expensive.

Innovation Solution

A biodegradable fatty stuff for ammunition cartridges composed of a cylindrical stamp and cup made from natural materials, such as cardboard and cork, which decompose within weeks to months, providing effective sealing and energy transfer without leaving harmful residues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If synthetic materials are used for wad and obturator, then sealing performance and durability are improved, but environmental pollution increases due to non-biodegradability

Engineering Contradiction:

Improvesealing performanceVSAvoidenvironmental pollution

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameters from synthetic to natural biodegradable materials (cardboard, cork, felt) while maintaining the sealing function through proper design of the cup-wad assembly and greasing treatment

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs disposable biodegradable materials that serve their function during firing and then decompose naturally, replacing permanent synthetic materials with temporary natural ones that return to the environment harmlessly

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If biodegradable materials are used for wad and obturator, then environmental pollution is reduced, but sealing performance and energy transfer efficiency deteriorate

Engineering Contradiction:

Improveenvironmental pollutionVSAvoidsealing performance

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent uses composite construction combining multiple natural materials (cardboard cup, cork pad, felt layer) with greasing treatment to achieve effective sealing and energy transfer while maintaining biodegradability

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces grease as an intermediary substance on the wad surface to enhance sealing between the biodegradable wad and the cartridge case, compensating for the lower sealability of natural materials

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If conventional greased wad is used, then energy transfer to shot is improved, but gas leakage and shot clustering increase due to insufficient sealing

Engineering Contradiction:

Improveenergy transfer to shotVSAvoidsealing consistency

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent divides the sealing function into multiple components: the cup structure provides initial containment, the cork pad provides compression sealing, and the grease layer provides surface sealing, with each segment contributing to overall sealing consistency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent incorporates a cork pad that compresses beforehand to cushion and seal the interface between the wad and cartridge case, preventing gas leakage before the high-pressure combustion phase begins

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 ensures a high-performance, environmentally friendly ammunition system that effectively transmits energy, reduces pollution, and enhances kinetic performance by up to 20%, while completely decomposing into harmless natural fragments, thus minimizing ecological impact.

Implementation Method 1

made up of at least 95% by weight of biodegradable or decomposable materials

Methodology Applied

Scientific EffectBiodegradation: Decomposition (biological)

Implementation Method 2

a cup made of plastically deformable material having a base fixed to said face and a collar extending from the base

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 3

The wad must also be compressible and elastic to absorb the shock of the powder's sudden ignition, transmitting the full force of the explosion to the shot

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 4

The wad was greased to improve the seal and reduce friction against the barrel

Methodology Applied

Scientific EffectLubrication: Lubrication

Data Source

PatentEP3875887B1Biodegradable fat wad with shutter for rifle cartridge

Publication Date: 2023.02.22 SHOOT HUNTING OUTDOOR

Figure 1a
Figure 1b
Figure 2a

AI summary

A greased wad intended to be placed in a cartridge between the explosive charge and the shot, comprising a cylindrical pad (1) adapted to fit into the cartridge case, said pad having two end faces (11, 12), at least one of which is provided with a cup (2', 2") of a plastically deformable material having a base (21) fixed to said face, and a collar (22) extending from the base (21) to a circular rim (23) adapted to be in contact with the inner face of the case, said greased wad being made of at least 95% by weight of biodegradable or biodegradable materials. A cartridge for a smoothbore shotgun is made by inserting this pre-assembled greased wad into the case.