Bolt Assembly Rotating Locking Head Bias Spring

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Solution Overview

Problem

Conventional rotating head bolts in hunting rifles can disengage from the locked position due to impacts, making it difficult to maintain a slow and silent locking motion, which can startle animals during hunting, and require manual intervention to re-lock, potentially missing a shot if unnoticed.

Innovation Solution

A bolt assembly with a bias means, comprising a ball and bias spring, that facilitates the locking of the rotating head by providing additional rotary and translational motion, ensuring the lugs align with the barrel seats, even under slow or impact-induced motions, preventing disengagement and ensuring a secure lock without altering the firearm's normal operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the rotating head is allowed to move freely with respect to the bolt body, then the bolt can operate normally during firing, but the rotating head may disengage from the locked position due to impacts

Engineering Contradiction:
Improvenormal operationVSAvoidlocked position stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by introducing a blocking element that prevents the rotating head from moving backward due to impacts before the problem occurs. The blocking element engages with the rotating head and the bolt body to restrict excessive rearward movement, thereby preventing disengagement from the locked position while allowing normal operation during firing.

Inventive Principle:
Principle #9Preliminary anti-action

2Reliability

If the hunter pushes the bolt sharply to lock it, then the rotating head can be forced into the locked position, but the animal may be startled and flee

Engineering Contradiction:
Improvelocking reliabilityVSAvoidnoise disturbance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The blocking element provides preliminary anti-action by preventing the rotating head from moving backward due to impacts before the problem occurs. This ensures the bolt remains locked without requiring sharp pushing motions that would create noise and startle the animal.

Inventive Principle:
Principle #9Preliminary anti-action

3Ease of operation

If the rotating head lacks residual energy to complete rotation, then the bolt can be locked manually, but the lugs may not align with the seats in the barrel

Engineering Contradiction:
Improvemanual lockingVSAvoidlug-seat alignment
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The blocking element ensures that the rotating head cannot move backward beyond a certain point, which prevents misalignment between the lugs and seats. By restricting excessive rearward movement, the blocking element ensures proper alignment is maintained or achieved during manual locking operations.

Inventive Principle:
Principle #9Preliminary anti-action

4Reliability

If a blocking element is added to prevent disengagement, then the locked position stability is improved, but the device complexity increases

Engineering Contradiction:
Improvelocked position stabilityVSAvoidblocking mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The blocking mechanism is segmented into discrete, simple components: a blocking element with a first engagement surface that interacts with the rotating head, and a second engagement surface that interacts with the bolt body. This segmentation allows the blocking function to be added without significantly increasing overall device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of making the rotating head actively engage with a complex locking mechanism, the patent uses a passive blocking element that simply prevents backward movement. This inversion of the approach—using a blocking rather than an active locking mechanism—reduces complexity while maintaining reliability.

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

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 bias means ensures reliable and silent locking of the bolt, preventing accidental disengagement and facilitating smooth operation, allowing hunters to load or re-lock the firearm quietly and securely, maintaining the firearm's operational integrity.

Implementation Method 1

a bias spring (103) contrasted by a rivet (104) forced in the radial hole (102)

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2775251B1Bolt assembly with improved rotating locking head
Publication Date: 2016.02.03 BENELLI ARMI SPA
  • EP2775251B1 patent drawingFigure 1
  • EP2775251B1 patent drawingFigure 2
  • EP2775251B1 patent drawingFigure 3

AI summary

A bolt assembly with improved rotating locking head, comprising a rotating locking head associated with a bolt body and movable with respect to the bolt body with a combined rotary and translational motion; the rotating locking head having at least two working positions: a closed position, wherein the rotating head closes the breech of the firearm, and an open position, wherein the rotating head is at a distance from the breech; the bolt assembly has an auxiliary pusher that biases the rotating head from the open position to the closed position.