Firearm Ejection Port Cover Actuated by Recoil Spring

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Solution Overview

Problem

Existing closing devices for operative side ports in firearms are unreliable under hostile environmental conditions, costly, and complex, especially for ambidextrous models, due to issues with recoil springs and elastic lips, which can lead to blockages and reduced functionality.

Innovation Solution

A closing device for the operative side ports of a receiver that uses a single cover movable along a rail, supported by a pair of springs integral to the bolt assembly, which opens and closes the slit openings without additional components, ensuring reliable operation and simplified assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cover moved by a recoil spring is used to close the slit opening, then the opening can be closed during bolt withdrawal, but the device becomes complex and unreliable under hostile environmental conditions

Engineering Contradiction:
Improvereliability of closing deviceVSAvoidcomplexity of closing device
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the cover for closing the slit opening with the ejection port cover into a single integrated component. This merging eliminates the need for separate closing mechanisms for both openings, reducing device complexity while maintaining the protective function. The integrated cover is actuated by the bolt-slide group itself, eliminating the need for additional recoil springs or elastic lips.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bolt-slide group is given a multi-function: it not only performs the ejection function but also actuates the cover to close the slit opening. The cover serves dual purposes by closing both the ejection port and the slit opening simultaneously. This multi-functionality reduces the number of dedicated components needed, simplifying the overall device.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If additional closing components are added to cover the slit opening, then protection against environmental factors is improved, but manufacturing and assembly costs increase

Engineering Contradiction:
Improveprotection against sand, dust, snowVSAvoidmanufacturing and assembly cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent merges the protection function for both the ejection port and slit opening into a single cover component. This integrated approach reduces the total number of parts that need to be manufactured and assembled, thereby lowering manufacturing and assembly costs while providing comprehensive protection against environmental contaminants.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single cover is designed to perform multiple protective functions by closing both the ejection port and the slit opening simultaneously. This universal protective component eliminates the need for separate closing mechanisms, reducing overall manufacturing complexity and cost while maintaining effective protection against sand, dust, and snow.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If the bolt-slide is lengthened to cover slit openings, then protection is improved, but the firearm length and weight increase

Engineering Contradiction:
Improveprotection of slit openingsVSAvoidlength of firearm
Core Design Contradiction:
Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The patent separates the protection function from the bolt-slide group by introducing a dedicated cover component. Instead of extending the bolt-slide to perform the closing function, the cover is positioned and actuated separately. This segmentation allows the bolt-slide to maintain its original dimensions while the cover provides the necessary protection, avoiding increases in firearm length.

Inventive Principle:
Principle #1Segmentation

4Device complexity

If elastic lips are used to close the slit openings, then a simple mechanism is achieved, but reliability decreases over time due to material degradation

Engineering Contradiction:
Improvesimplicity of closing mechanismVSAvoidreliability over time
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces the durable but complex recoil spring mechanism with a simpler, potentially sacrificial cover design. The cover can be made from resilient materials that provide the necessary closing action without requiring long-term elastic memory. This approach prioritizes simplicity and cost-effectiveness while maintaining adequate reliability for the service life of the firearm.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 provides a reliable, cost-effective, and simple closing mechanism for firearms, maintaining functionality under adverse conditions without increasing the firearm's length or weight, and is suitable for ambidextrous designs with reduced assembly costs and enhanced reliability.

Implementation Method 1

which, upon withdrawing, overcomes the force of a specific recoil spring, which is constrained to the cover

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

two rubbery closing lips are assembled parallel to the slit openings for their whole length. When the cocking handle, in its withdrawal, enters the area of the elastic closing lips, it deforms them and moves them to complete its trajectory

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2045564B1Ejection port covers for a firearm
Publication Date: 2014.04.09 FABBRICA DARMI PIETRO BERETTA SPA
  • EP2045564B1 patent drawingFigure 1
  • EP2045564B1 patent drawingFigure 2
  • EP2045564B1 patent drawingFigure 3~4

AI summary

In a firearm with a closing device of operative side ports of a receiver, comprising a bolt assembly (20) and a receiver (12) equipped on at least one side with an operational port (13), wherein the bolt assembly (20) comprises a bolt (21), a bolt-holder slide (22) carrying a cocking handle (24) and an inertial return element (23) of the bolt-slide (22), a closing device (30) comprises at least one cover (31) which can be moved along a longitudinal rail (32) from an advanced engagement position with the at least one operational side port (13) and a withdrawn disengaged position, wherein the inertial element (23) comprises a first spring (23A) and a second spring (23B) applied in series on the longitudinal rail (32) and in which supporting means (33) of the at least one cover (31) are assembled axially and slide along the longitudinal rail (32) between the first spring (23A) and the second spring (23B).