Rotary Bolt Head Locking Without Extension
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Solution Overview
Problem
Traditional rotary bolt designs in shotguns require longer barrel extensions and receivers, adding weight, complexity, and cost due to the need for substantial bolt head extension during operation, which complicates machining around the lockup and chamber area.
Innovation Solution
A bolt assembly with a rotatable bolt head that locks into battery without extending from the bolt body, utilizing a cam pin and bolt carrier to rotate the bolt head, allowing for a compact design with reduced receiver and barrel extension length, and incorporating features like a bolt carrier blocker and shell support for efficient shell ejection and loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional rotary bolt design is used with substantial bolt head extension, then the bolt can effectively engage and extract shells, but the barrel extension and receiver length increase, adding weight and complexity
Solution Approach 1:
The bolt head is designed to rotate dynamically within the bolt body rather than extending linearly. The cam pin mechanism converts the linear motion of the bolt carrier into rotational motion of the bolt head, allowing the bolt to engage and disengage without requiring substantial extension of the bolt head beyond the bolt body.
Solution Approach 2:
The invention transitions from linear extension (traditional rotary bolt design) to rotational movement within a constrained space. The bolt head rotates about an axis within the bolt body, utilizing angular displacement rather than linear displacement to achieve engagement and extraction functions.
2Reliability
If a traditional rotary bolt design with substantial bolt head extension is used, then shell extraction and engagement are enabled, but the receiver length increases, adding weight and manufacturing complexity
Solution Approach 1:
The bolt head rotation mechanism is merged within the bolt body structure itself, eliminating the need for separate external rotation mechanisms. The cam pin and cam surface are integrated into the bolt carrier and bolt head assembly, reducing the overall complexity of the receiver and barrel extension requirements.
3Ease of operation
If longer barrel extensions are provided to accommodate translating bolt head, then bolt operation is enabled, but machining difficulty increases around lockup and chamber area
Solution Approach 1:
The bolt head rotates dynamically within the bolt body during operation, eliminating the need for long stationary barrel extensions. This dynamic rotation allows the bolt to engage and disengage shells while maintaining a compact profile that is easier to machine around the lockup and chamber areas.
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 compact design reduces the length and weight of the firearm, simplifies machining, and eliminates the need for extensive barrel and receiver features, enhancing operational efficiency and manufacturing ease.
Implementation Method 1
The bolt carrier further includes a cam pin that extends into a cam surface cut in the bolt head such that the longitudinal or translating movement of the bolt carrier, and thus the cam pin therewith, causes the bolt head to rotate.
Data Source
AI summary
A bolt assembly for a firearm such as an auto-loading or pump action shotgun includes a bolt body, bolt carrier and a bolt head. The bolt head is received within the bolt body and is rotatable within the bolt body to lock the bolt assembly into battery prior to firing the weapon, but does not extend from the bolt body during such rotation. The bolt carrier translates axially relative to the bolt body so as to cause rotation of the bolt head. The extractor for the firearm can be pivotally attached to the bolt body, while the ejector further can be integrated into the bolt assembly for engaging and ejecting a shell or cartridge after firing.