Mortar Grenade Sealing Ring Stabilization
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Solution Overview
Problem
Mortar shells face a conflict between requiring sufficient projectile clearance for loading and minimizing propellant gas leakage during firing, with existing sealing rings being prone to undesirable expansion and environmental influence on adhesive bonds.
Innovation Solution
A sealing ring stabilized by an annular element, such as an O-ring or ring-shaped spring, which holds the sealing ring in place during loading and expands outward against the barrel when fired, eliminating the need for gluing and ensuring reliable sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a sufficiently large projectile clearance is provided to ensure loading of the mortar from the muzzle, then the mortar shell can be loaded freely, but propellant gases can sweep past the mortar shell during firing
Solution Approach 1:
The sealing ring is designed to be dynamically adjustable between two states: during loading, the ring remains in a relaxed state allowing sufficient projectile clearance for easy loading; during firing, the high gas pressure causes the ring to expand and seal against the barrel wall, preventing gas leakage. This dynamic adaptation resolves the contradiction between loading ease and gas sealing reliability.
Solution Approach 2:
The sealing ring's cross-sectional dimensions change in response to gas pressure. During loading, the ring maintains a smaller effective size allowing clearance; during firing, the propellant gases cause the ring to expand to a larger size that seals against the barrel. This parameter change enables the system to satisfy both contradictory requirements under different operational conditions.
2Reliability
If a sealing ring is used to prevent propellant gas leakage, then gas sealing is improved, but the sealing ring may expand undesirably during loading
Solution Approach 1:
The sealing ring is pre-formed with a specific cross-sectional shape and size that is optimized for the loading phase. This preliminary configuration ensures that during loading, the ring does not expand undesirably and maintains stability, while still being capable of expanding to the sealed configuration when gas pressure is applied during firing.
Solution Approach 2:
The sealing ring utilizes material properties and geometric design that allow it to maintain a stable, controlled configuration during loading, then transition to an expanded sealed configuration when subjected to propellant gas pressure. The parameter change is triggered by the gas pressure itself, ensuring stability during loading and sealing during firing.
3Ease of manufacture
If adhesive bonding is used to join sealing ring parts, then assembly is simplified, but environmental influences can undesirably affect the adhesive bond properties
Solution Approach 1:
The sealing ring is designed to be self-contained and self-stabilizing through its geometric configuration and material properties. The ring's cross-sectional shape and dimensions are engineered to provide inherent stability during loading and automatic sealing capability during firing, eliminating the need for external adhesive bonds and their associated environmental vulnerabilities.
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
This solution provides reliable sealing, defined free-fall initiation of the propellant charge, easy assembly, long-term stability, and cost-effectiveness while preventing air cushion formation and environmental influence on adhesive bonds.
Implementation Method 1
the propellant gases only press the sealing ring outwards when the respective mortar shell is fired, so that it is pressed against the inner surface of the weapon barrel and forms a gas seal
Implementation Method 2
the sealing ring is designed in such a way that it allows a sufficiently large projectile play when loading the corresponding mortar and that the propellant gases only press the sealing ring outwards
Implementation Method 3
the ring-shaped element consists of a material which is selected in such a way that the ring-shaped element holds the sealing ring in a predetermined rest position when the mortar shell is being loaded
Implementation Method 4
the mortar shell can fall freely into the weapon barrel
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a mortar grenade (1) having a peripheral annular recess (5), in which a sealing ring (6) made of an elastic material is housed, said sealing ring expanding when firing the mortar grenade (1) from a mortar by applying propellant gases and being pressed against the inner surface of the gun barrel of the mortar. In order to prevent the formation of an air cushion on the rear side in the mortar barrel during loading of the mortar grenade (1) and also to ensure a defined expansion of the sealing ring (6) when firing the mortar grenade (1), according to the invention the sealing ring (6) is stabilized by an annular element (9). For this purpose, the annular element (9) is made of a material that is selected such that the annular element (9) keeps the sealing ring (6) in a resting position when loading the mortar grenade (1) such that the mortar grenade (1) can drop freely into the gun barrel. The annular element (9) however does not, or not significantly, prevent the expansion of the sealing ring (6) during firing of the mortar grenade (1).