Flexible Retaining Lips and Conical Guide for Firearm Magazine Loading

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Solution Overview

Problem

Traditional single column cartridge magazines require detachment from the firearm for loading and lack precise guidance for cartridge positioning, which can affect accuracy due to sideways movement and improper alignment of cartridges.

Innovation Solution

The design incorporates stiff but bendable retaining lips made from materials like steel or aluminum, combined with a flexible polymer or fiber-reinforced polymer box, and a cartridge guide with beveled edges to guide the frusto-conical shoulder portion of the cartridge, allowing for precise positioning and loading without horizontal movement, enabling loading while attached to the firearm.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional retaining lips design is used with mutual distance smaller than cartridge case diameter, then the retaining lips can function correctly to hold cartridges, but the magazine must be detached from the firearm for loading

Engineering Contradiction:
Improveretaining lips functionVSAvoidloading convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The retaining lips are made flexible rather than rigid, allowing them to dynamically adjust their position. When a cartridge is inserted, the retaining lips bend outward to accommodate the cartridge diameter, then return to their original position to secure the cartridge. This dynamic behavior enables loading through the ejection opening while maintaining reliable cartridge retention.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mutual distance between retaining lips is changed from a fixed small value to a variable value that can expand to accommodate the cartridge case diameter during loading, then return to the smaller value for retention. This parameter change is achieved through the flexible material property of the retaining lips.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If cartridges are fed without precise guidance, then the magazine structure is simpler, but cartridges experience sideways movement affecting accuracy

Engineering Contradiction:
Improvemagazine structureVSAvoidcartridge positioning accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

A cartridge guide is introduced as an intermediary component between the cartridges and the chamber. This guide features a conical surface that interfaces with the conical shoulder of the cartridge, precisely guiding the cartridge's horizontal movement into the chamber without requiring complex magazine structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Both the cartridge guide surface and the cartridge shoulder are designed with conical (curved) geometries. The conical surface of the cartridge guide mates with the conical shoulder of the cartridge, creating a precise guiding interface that ensures accurate cartridge positioning while maintaining relatively simple magazine construction.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

This solution ensures precise positioning of cartridges, maintaining accuracy and reliability by eliminating sideways movement and allowing for easy loading through the ejection opening, even when the magazine is attached, thus enhancing the feeding action and reducing noise.

Implementation Method 1

The flexibility is achieved by the elasticity of the retaining lip construction

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the bullet and it slides along the feeding ramp and guides the cartridge into the chamber

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2160561B1Cartridge magazine for firearms
Publication Date: 2016.08.31 SAKO
  • EP2160561B1 patent drawingFigure 1A~1B
  • EP2160561B1 patent drawingFigure 2
  • EP2160561B1 patent drawingFigure 3~6

AI summary

A cartridge magazine for firearms has an elongated channel to receive a plurality of cartridges. The cartridge magazine has a box forming a housing of the cartridge magazine, a spring operated follower for pressing the cartridges in the magazine to an upper position. In this position, the topmost cartridge is ready for feeding into a chamber of the firearm and in this position the topmost cartridge rests against a pair of retaining lips. The lips remain in a first position when the topmost cartridge is in the upper position and the lips are operatively displaceable to a second position wider than the first position.