Firearm Bolt Carrier Wheel Alignment Mechanism
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Solution Overview
Problem
Conventional bolt carriers in firearms experience misalignment and increased friction within the upper receiver and buffer tube, leading to poor performance due to spacing tolerances and vibrations during firing.
Innovation Solution
A bolt carrier with a cylindrical body featuring a first and second slot, and an annular wheel within the second slot, which provides improved alignment and reduced friction through axial engagement with the buffer tube, inhibiting rotational and vibrational movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lands are used on the bolt carrier, then alignment with the upper receiver is provided, but spacing tolerances and vibrations cause misalignment with the buffer tube and increased friction
Solution Approach 1:
The patent introduces a wheel structure with a curved, circular cross-section that rotates within a slot in the bolt carrier. This curved geometry replaces the conventional flat lands, allowing the wheel to maintain continuous rotational contact with the buffer tube during reciprocation. The circular profile ensures smooth engagement and alignment tolerance compensation, eliminating the misalignment issues caused by conventional lands while reducing friction through rolling contact.
2Ease of operation
If spacing tolerances are permitted for bolt carrier reciprocation, then the bolt carrier can move freely, but this creates misalignment and poor engagement with the buffer tube
Solution Approach 1:
The wheel acts as an intermediary element between the bolt carrier and the buffer tube. It is mounted on an axle within a slot in the bolt carrier, allowing the wheel to rotate freely while maintaining engagement with the buffer tube. This intermediary structure absorbs the spacing tolerances and vibration effects, ensuring consistent alignment and engagement without restricting the necessary reciprocation freedom of the bolt carrier.
3Manufacturing precision
If conventional lands engage the upper receiver, then alignment is provided, but friction increases during reciprocating motion
Solution Approach 1:
The wheel's curved, circular cross-section enables rolling contact with the buffer tube during reciprocation, replacing the sliding friction of conventional lands with rolling friction. This curvature allows the wheel to maintain alignment while significantly reducing the friction force required for reciprocating motion, as rolling contact generates less resistance than sliding contact.
Solution Approach 2:
The wheel is designed to rotate dynamically within its slot as the bolt carrier reciprocates. This dynamic rotation allows the wheel to continuously adapt its contact point with the buffer tube, maintaining optimal engagement while reducing friction. The rotational degree of freedom enables the system to accommodate vibration and tolerance variations without increasing frictional resistance.
Data Source
AI summary
A bolt carrier for a firearm that includes a rolling element so as to provide improved alignment and reduced friction of the bolt carrier with the upper assembly and buffer tube as the bolt carrier executes a reciprocating motion. The bolt carrier includes a body that is generally cylindrical in shape having a first end and a second end. The body of the bolt carrier includes a first slot and a second slot. The first slot includes an upper opening and a lower opening. The second slot is proximate the second end of the body of the bolt carrier. The second slot includes an upper opening and a lower opening providing access to the interior volume of the second slot. A wheel is rotatably mounted within the second slot. The upper edge and lower edge of the wheel extends beyond the top side and bottom side of the body respectively.