Roller-Delayed Blowback Bolt for Smooth Manual Cycling
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Solution Overview
Problem
Existing auto-loading firearms with roller delayed blow-back systems require high initial force for manual cycling, making operation difficult for those with less hand or arm strength, and cause jerky cycling due to sudden force drops.
Innovation Solution
A modified blow-back bolt and recoil spring/buffer system with a longitudinally movable actuator and release component that allows for consistent force during both stages of manual cycling, using a recoil spring to disengage the roller lock mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a roller delayed blow-back system is used to delay breach opening, then chamber pressure drops to safe level before breach opens, but high initial force is required for manual cycling
Solution Approach 1:
The manual cycling process is divided into two distinct stages: Stage 1 moves the actuator and release component to disengage the roller from the recess (resisted only by recoil spring), while Stage 2 moves the bolt body (also resisted only by recoil spring). This segmentation eliminates the need to overcome roller friction during manual cycling, reducing the required force while maintaining the roller delay function for automatic cycling.
Solution Approach 2:
The system dynamically changes its mechanical characteristics based on the cycling mode. During automatic cycling, the roller engages the recess to create high resistance and delay breach opening. During manual cycling, the actuator and release component mechanism allows the roller to disengage from the recess, transitioning to a low-resistance state where only the recoil spring provides resistance throughout both stages of movement.
2Reliability
If high initial force is required to disengage roller lock-up, then breach opening is delayed until safe pressure level, but hand cycling becomes jerky due to sudden force drop
Solution Approach 1:
The manual cycling movement is segmented into two stages, both of which are resisted only by the recoil spring without sudden force changes. Stage 1 (actuator and release component movement) and Stage 2 (bolt body movement) both provide consistent, smooth resistance, eliminating the jerky sensation caused by sudden force drops in traditional roller-delayed systems.
Solution Approach 2:
The actuator and release component serve as intermediaries that decouple the roller lock mechanism from the manual cycling force requirement. These components allow the roller to disengage from the recess through a controlled mechanism rather than requiring sudden high force, enabling smooth transitions throughout the manual cycling process while maintaining the roller delay function for automatic cycling.
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
Enables smooth and consistent manual cycling of the firearm action with reduced initial force requirement, improving usability for users with less strength and eliminating jerky movements.
Implementation Method 1
a recoil spring on the guide rod configured to bias the release component forwardly
Implementation Method 2
When the roller body is engaged in the guide rod recess, the release component and forward abutment are longitudinally slidably detained relative to the guide rod
Implementation Method 3
Rearward sliding movement of the actuator by manual cycling engages and displaces the release component relative to the forward abutment such that the at least one roller disengages from the guide rod recess
Data Source
AI summary
Provided is a blow-back bolt and recoil spring/buffer system for an autoloading firearm action. The blow-back bolt includes a bolt body and an actuator that is longitudinally movable relative to the bolt body to a limited extent by manual cycling. The recoil spring/buffer system has a longitudinal guide rod with at least one recess, a release component and a forward abutment slidably arranged together on the guide rod, a recoil spring is configured to bias the release component forwardly, and at least one roller body is arranged between the release component and the forward abutment. When the roller body is engaged in the recess, the release component and forward abutment are longitudinally slidably detained relative to the guide rod. Rearward movement of the actuator by manual cycling engages and displaces the release component such that the roller disengages from the guide rod recess to allow undetained rearward sliding movement against the recoil spring.