Spring-Assisted Breech Bolt Locking for Easier Retraction

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Solution Overview

Problem

Existing firearms, particularly self-loading systems, face challenges with increasingly difficult breech retraction movements and inefficient locking mechanisms, especially in manual and semi-automatic weapons, leading to suboptimal operation and safety concerns.

Innovation Solution

A locking system featuring a saw thread design with inclined flanks on both sides of the thread, allowing for a breechblock and barrel to engage through rotation, facilitated by a spring-assisted mechanism, ensuring secure locking and easy operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional locking mechanisms are used in self-loading firearms, then the locking security is maintained, but the breech retraction movement becomes increasingly difficult with each cycle

Engineering Contradiction:
Improvelocking securityVSAvoidbreech retraction movement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the geometric parameters of the locking lugs and recesses to create a more favorable engagement profile. The locking lugs are designed with specific angles and dimensions that reduce friction and mechanical binding during retraction, making the breech movement easier while preserving secure locking when engaged.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The locking mechanism incorporates dynamic elements that allow the locking lugs to smoothly enter and exit their recesses during the cycling operation. The design enables controlled movement through the locking engagement and disengagement phases, reducing operational difficulty while maintaining reliability.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If manual bolt action systems are used, then simple construction is achieved, but the locking and unlocking process requires multiple rotational steps reducing efficiency

Engineering Contradiction:
Improvebolt action constructionVSAvoidloading speed
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The bolt action is segmented into distinct functional zones: a locking zone with engagement features, a travel zone for linear movement, and an unlocking zone. This segmentation allows the bolt to perform locking and unlocking actions during its linear travel without requiring additional rotational steps, improving loading speed while keeping construction simple.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of rotating the bolt to achieve locking and unlocking, the patent inverts the conventional approach by using linear motion to accomplish these functions. The locking lugs engage and disengage through the linear travel of the bolt, eliminating the need for rotational operations and thereby increasing productivity.

Inventive Principle:
Principle #13The other way round (Inversion)

3Productivity

If straight-pull repeater mechanisms are used, then operation speed is improved, but reliable locking under high gas pressure becomes challenging

Engineering Contradiction:
Improveoperation speedVSAvoidlocking security under pressure
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The locking lugs are designed with asymmetric profiles where the engagement surfaces are optimized for both rapid engagement and high-pressure retention. The asymmetric geometry allows the lugs to quickly snap into place during straight-pull operation while maintaining strong mechanical interference that resists high gas pressures.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The locking surfaces incorporate curved and rounded features that facilitate smooth engagement during the rapid straight-pull operation. The curvature allows the locking lugs to naturally guide themselves into proper alignment during high-speed cycling, ensuring reliable locking under pressure without sacrificing operation speed.

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

The system provides reliable, secure locking with simplified loading and unloading processes, suitable for both manual and automatic firearms, enhancing operational ease and safety.

Implementation Method 1

facilitated by a spring-assisted mechanism

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

corresponding engagement means are formed as threads with or without a pitch

Methodology Applied
Scientific EffectThreaded fastening: Screw

Implementation Method 3

at least the rear flank of the at least one threaded ridge of the bolt head is inclined against the direction of fire

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP4070027B1Breech system
Publication Date: 2025.12.24 PRAZISIONSTECHNIK VOLKACH WILFRIED ALBER GEORG HOLTHAUS GBR
  • EP4070027B1 patent drawingFigure 1
  • EP4070027B1 patent drawingFigure 2
  • EP4070027B1 patent drawingFigure 3

AI summary

The invention relates to a breech system for a firearm, comprising a breech receiver and a breech bolt, wherein the breech receiver is designed as a hollow cylinder with at least radially inwardly projecting engagement means and furthermore a breech bolt head is provided, which has outwardly projecting engagement means corresponding to the inwardly projecting engagement means, wherein the breech bolt head is rotatably mounted on a breech carrier and furthermore a breech body is present, which is displaceable on a breech bolt head shaft of the breech bolt head and at least one compression spring is provided between the breech body and the breech carrier, which spring is provided to move the breech body towards the breech bolt head, wherein means are provided on the breech bolt head shaft and on the breech body and cause rotation of the breech bolt head upon displacement of the breech body on the breech bolt head shaft.