Projectile Cup Ejection via Segmented Collar and Elastic Seal
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Solution Overview
Problem
The existing projectiles suffer from aerodynamic braking due to a bulge on the body of the projectile, which limits their range, as the bulge acts as an obstacle to air flow and the groove accommodating the O-ring causes discontinuity in the air flow, reducing the projectile's range.
Innovation Solution
A projectile design featuring a cup with a bottom and a longitudinally extending wall, where the edge of the wall is pinched between a seal and a collar with an annular part, utilizing a clamping mechanism comprising a nut and elastic rings that expand radially to seal against the cup's edge, and a collar composed of angularly distributed sectors to prevent radial disunion, which fragments under centrifugal forces during firing, allowing the cup to be ejected and reducing aerodynamic braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bulge with a groove accommodating an O-ring is used to seal the cup to the projectile body, then gas tightness is ensured, but aerodynamic braking increases due to the discontinuity in airflow
Solution Approach 1:
The collar is divided into multiple angular sectors that are assembled together, creating a segmented structure that reduces airflow disruption compared to a continuous bulge. The sectors are arranged with gaps between them, allowing airflow to pass through more smoothly while still providing the necessary sealing function when combined with the elastic ring.
Solution Approach 2:
The sealing function is localized to specific regions where elastic rings are positioned between the collar sectors and the cup edge, rather than requiring a continuous bulge structure. This allows the majority of the collar surface to be aerodynamic while maintaining gas tightness at critical locations.
2Stability of the object's composition
If a collar with an annular part is used to center and support the cup, then structural stability is improved, but aerodynamic performance deteriorates due to the obstacle to airflow
Solution Approach 1:
The collar is segmented into multiple angular sectors that can be assembled to form the complete circular structure. This segmentation reduces the aerodynamic footprint and allows airflow to pass through the gaps between sectors, significantly reducing drag while maintaining the structural support function.
Solution Approach 2:
The collar structure is designed to be dynamic, with sectors that can move or flex under aerodynamic loads, and elastic rings that provide flexible sealing. This dynamic behavior allows the structure to adapt to airflow conditions while maintaining stability and sealing function.
3Reliability
If a clamping means with a nut and elastic rings is used to press the seal, then reliable sealing is achieved, but device complexity increases
Solution Approach 1:
The elastic rings change their physical parameters (radial expansion) in response to the clamping force from the nut, transforming a simple rotational fastening action into an effective sealing pressure. This parameter change allows reliable sealing with a relatively simple clamping mechanism.
Solution Approach 2:
The nut is designed to be fragmentable by centrifugal forces during firing, meaning it serves its purpose temporarily to install the seal and then breaks apart. This disposable approach simplifies the overall mechanism by eliminating the need for complex retention systems for the clamping means.
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 design enhances the range of the projectile by minimizing aerodynamic braking while maintaining protection from propellant gases during firing, as the cup is released and the collar and elastic rings are dispersed, allowing the projectile to maintain aerodynamic integrity and increase its range.
Implementation Method 1
a clamping means that presses the seal against the annular part of the collar, causing radial expansion of the seal
Implementation Method 2
the nut being fragmentable by the action of centrifugal forces developed during firing
Data Source
Figure 1a~1b
Figure 1c
Figure 2a
AI summary
The invention relates to a projectile (1) comprising an ejectable cup designed to protect the base of the projectile (1) from propellant gases. The cup has a wall (5b) surrounding the base and extending to a position where the edge (5c) of the wall (5b) is pinched between a seal (8) surrounding the body of the projectile (1) and a collar (4). The collar comprises an annular portion (4a) centered on a first cylindrical bearing surface (D1) having a first diameter (D1). The first bearing surface (D1) is separated from a second bearing surface (D2) by a shoulder whose face (10) is oriented towards the rear (AR) of the projectile (1). A clamping means (13) presses the seal (8) against the annular portion (4a), which radially expands the seal (8), pressing it against the edge (5c) of the cup.