Constant Force Spring for Firearm Breechblock Recoil Management
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Solution Overview
Problem
Conventional firearms with return springs experience increasing resistance during recoil, leading to discomfort and instability for the user, as the resistance force is not constant, and the production of torsion springs is complex with non-constant tensile force.
Innovation Solution
A firearm utilizing a constant force return spring, composed of a flat ribbon wound in a spiral form with contiguous turns, mounted between the breech and a fixed support, providing a consistent resistance force during recoil, and protected within a casing for durability and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional compression spring is used as the return spring, then the breech can be returned to its closed position, but the resistance increases progressively during recoil movement requiring increasing force
Solution Approach 1:
The patent changes the force characteristic parameter of the return spring from progressive (compression spring) to constant (torsion spring). The torsion spring is designed with a specific geometry where the moment arm varies in inverse proportion to the spring deflection, maintaining a constant torque throughout the recoil movement. This resolves the contradiction by providing consistent resistance force that does not increase progressively.
Solution Approach 2:
The patent introduces a dynamic element (the torsion spring's rotational movement) to achieve a static outcome (constant resistance force). As the breech recoils, the torsion spring rotates around its axis, and the varying lever arm length dynamically compensates for the changing spring deflection, maintaining constant force throughout the motion range.
2Ease of operation
If a torsion spring is used as the return spring, then constant resistance force is achieved, but the spring is complicated to produce with non-constant tensile force
Solution Approach 1:
The patent specifies precise geometric parameters for the torsion spring (arm length, width, thickness, spiral configuration) that can be manufactured using standard metal forming processes. The constant force characteristic is achieved through carefully controlled dimensional parameters rather than complex manufacturing steps, making the spring producible with conventional techniques.
3Ease of operation
If the return spring resistance is constant, then user comfort and stability are improved, but the spring requires a different mounting system compared to conventional springs
Solution Approach 1:
The patent designs the mounting system to serve multiple functions: it provides the pivot axis for the torsion spring, anchors the spring ends, and integrates with the existing breech and stock structure. The mounting brackets and pivot points are designed to be incorporated into standard firearm components, reducing overall device complexity despite the different spring type.
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 constant force return spring enhances user comfort and stability by maintaining a consistent resistance force, reducing the effort required for rearming and improving the overall handling of the firearm.
Implementation Method 1
the return spring is a tension spring of the so-called constant force type which is mounted between the breech and a support fixed with respect to the carcass and the barrel
Data Source
Figure 1
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Figure 4~5
AI summary
Firearm comprising a frame (2); a barrel (6) mounted with one end on the frame (2); a breechblock (8) provided with a cocking handle (9) and mounted in a sliding manner in the frame (2); at least one return spring (15) for returning the breechblock (8) to the closed position, characterized in that the return spring (15) is a constant force type tension spring which is mounted between the breechblock (8) and a support (12) fixed relative to the frame and the barrel.