Reusable Return Valve Sealing for Percussion Firearm Shell Cases
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Solution Overview
Problem
Existing shell case sealing systems in historical percussion firearms suffer from incomplete sealing, leading to back-blow of gunpowder gases and resulting in reduced efficiency and accuracy due to black powder residue, which causes frequent jams and misfires.
Innovation Solution
A shell case sealing system featuring conical angle notches around the flash hole and a reusable return valve with a sliding ball mechanism that ensures complete closure after firing, preventing gas leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing system with flash channels is used (HYDRAsystem), then the shell case sealing is improved, but gunpowder gases back-blow onto the gun-lock causing black powder residue
Solution Approach 1:
A valve mechanism is introduced as an intermediary component between the shell case interior and the flash hole. This valve selectively controls gas flow: allowing ignition gases to pass through to initiate firing, while preventing high-pressure gunpowder gases from back-flowing onto the gun-lock. The valve thus mediates between the need for ignition and the need to prevent contamination.
Solution Approach 2:
The sealing system transitions from a static flash hole configuration to a dynamic valve-controlled system. The valve moves between open and closed positions based on pressure differential: remaining open during ignition to allow gas flow, then closing automatically when gunpowder charge ignition creates high pressure, thereby dynamically adapting the sealing behavior to different operational phases.
2Device complexity
If traditional sealing systems are used, then the structure is simple, but complete tightness is not achieved leading to gas leakage
Solution Approach 1:
The valve mechanism is designed to operate automatically without external control or manual intervention. It self-regulates based on pressure differential: the high pressure from gunpowder charge ignition automatically forces the valve closed, while the lower pressure during ignition allows it to remain open. This self-service operation eliminates the need for complex external control systems while achieving complete sealing.
3Reliability
If a reusable return valve is used, then sealing reliability is improved, but device complexity increases
Solution Approach 1:
The complex valve mechanism is extracted as a separate, modular component that can be independently manufactured, tested, and replaced. The valve is designed as a distinct assembly with standardized interfaces to the shell case, allowing it to be removed and replaced without affecting the overall shell case structure. This modularity manages complexity by isolating the complex function into a self-contained unit.
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 achieves 100% sealing, eliminating misfires and jams, and maintains firearm functionality and accuracy even after 500 test shots, enhancing repeatability and efficiency.
Implementation Method 1
In a hole 9 of rear part 6 of a shell case 5 are located angle notches 7 around flash hole 9 for gases (fig. 1). These notches are of conical shape and positioned symmetrically around shell case axis
Implementation Method 2
The return valve, which consists of bushing 2 and ball 3 is a reusable component... a sliding ball 3 inside... acting on ball 3, they are causing it to lean against a hole 9 of a shell case... closing its hole 10 and making flow out of gases impossible
Data Source
Figure 1~2
Figure 3~4
AI summary
The subject of invention is the shell case sealing in a historical percussion firearm, with return valve in a rear part of a shell case, characterized in that it is a reusable return valve (1) sliding in a recess of a rear part (6) of a shell case (5), which is a cylindrical bushing (2) with a hole (10) and inner cut out (4) of conical shape with added sliding ball (3) to inside, wherein the hole (9) operating with a ball (3) is bearing the notches (7), positioned symmetrically versus axis of a shell casing.