Automatic Sear Assembly with Bidirectional Sear Lever
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Solution Overview
Problem
Large-bore rifles face challenges in achieving selective-fire capabilities due to the large and heavy sear lever, which adds moving mass to the bolt carrier, leading to potential failure and damage to the rifle's components.
Innovation Solution
An automatic sear assembly with a sear lever that has bidirectional articulation, allowing it to impart torque to the automatic sear for full-automatic firing without direct contact with the bolt carrier, reducing mechanical complexity and preventing unwanted tripping, and is compatible with various caliber rifles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large and heavy sear lever is used to provide full-automatic firing capability, then selective-fire capability is achieved, but moving mass increases leading to potential failure and component damage
Solution Approach 1:
The sear lever is segmented into multiple components: a sear lever body, a sear lever arm, and a sear lever spring. This segmentation allows the system to achieve full-automatic firing capability through coordinated movement of lighter components rather than a single heavy lever, reducing overall moving mass while maintaining functionality.
Solution Approach 2:
The sear lever is designed with bidirectional articulation capability, allowing it to rotate in both directions about its pivot axis. This dynamic design enables the sear lever to impart torque to the automatic sear for full-automatic firing while also being able to return to its neutral position, providing selective-fire capability without requiring a heavy-duty unidirectional lever.
2Extent of automation
If the sear lever directly contacts the bolt carrier to receive force, then full-automatic firing is enabled, but mechanical complexity increases and unwanted tripping may occur
Solution Approach 1:
The sear lever arm acts as an intermediary between the bolt carrier and the automatic sear. Instead of direct contact between the bolt carrier and the sear mechanism, the sear lever arm receives force from the bolt carrier through its incident configuration, then transmits this force to impart torque to the automatic sear. This intermediary arrangement reduces mechanical complexity and prevents unwanted tripping by providing a controlled force transmission path.
Solution Approach 2:
The sear lever arm is configured to be incident with the bolt carrier, allowing it to receive force in a direction perpendicular to the bolt carrier's motion. This dimensional change in force reception allows the system to convert linear bolt carrier motion into rotational torque on the automatic sear without requiring complex mechanical linkages.
3Ease of operation
If the sear lever extends beyond the automatic sear height, then bidirectional articulation is achieved, but device complexity increases
Solution Approach 1:
The sear lever body serves multiple functions: it provides the pivot axis for bidirectional rotation, supports the sear lever arm for force reception, accommodates the sear lever spring for biasing, and enables both full-automatic and semi-automatic firing modes. This multi-functionality reduces device complexity by consolidating multiple requirements into a single component rather than requiring separate mechanisms for each function.
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 solution enables reliable full-automatic and burst firing capabilities while maintaining mechanical reliability and reducing the likelihood of binding, with minimal added mass and cost, and is adaptable for different caliber rifles.
Implementation Method 1
a first spring disposed adjacent the sear lever and the rear surface of the automatic sear and configured to bias the sear lever into physical contact with the rear surface of the automatic sear
Implementation Method 2
a second spring disposed adjacent the sear lever and the rear surface of the automatic sear and configured to operatively interface with the safe/fire selector switch
Data Source
AI summary
An automatic sear assembly for providing a large-bore rifle with full-automatic firing and/or burst firing capabilities is disclosed. In accordance with some embodiments, the disclosed assembly includes an automatic sear operatively configured with a sear lever which is provided with bidirectional articulation for selectively imparting torque on the automatic sear to cause tripping thereof. For example, the disclosed assembly can be configured such that rotational deflection of the sear lever away from the automatic sear imparts no rotation thereto, whereas rotational deflection of the sear lever toward the automatic sear imparts rotation thereto. Thus, and in accordance with some embodiments, the disclosed sear assembly can be used in a rifle, for example, to utilize the force of a moving bolt carrier during a given firing cycle to initiate a subsequent firing cycle without need to release and once again operate the trigger of the rifle.