Rounded Cubic Shot Packing Density and Flow

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Solution Overview

Problem

Conventional shot shapes, such as spherical and flattened spherical, fail to provide ease of manufacturing, optimal projectile pattern, and packing density, leading to poor flow characteristics in metering devices and increased pattern dispersion.

Innovation Solution

The development of rounded cubic shot with edges and corners having a radius of curvature between 15% and 40% of the cube's face distance, which improves packing density and flow characteristics, allowing for higher payloads and velocities in shotshells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional spherical shot is used, then manufacturing is simple and flow characteristics are acceptable, but packing density is low and pattern dispersion is high

Engineering Contradiction:

Improvepacking densityVSAvoidmanufacturing complexity

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent applies curvature to the edges and corners of cubic shot, creating a hybrid shape that combines the high packing density of cubes with the flow characteristics of spheres. The rounded edges eliminate sharp corners while maintaining the overall cubic geometry, achieving both improved packing density and acceptable flow characteristics without complex manufacturing processes

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters of cubic shot by introducing specific edge and corner radii (R1 and R2) that are optimized to achieve high packing density. By controlling the radius of curvature relative to the cube dimensions, the invention achieves superior packing while maintaining manufacturing simplicity through standard casting or forming processes

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If cubic shot with sharp edges is used, then packing density is high, but flow characteristics through metering devices are poor

Engineering Contradiction:

Improvepacking densityVSAvoidflow characteristics

Core Design Contradiction:

Quantity of substanceVSEase of operation

Solution Approach 1:

The patent introduces rounded edges and corners to cubic shot, eliminating sharp corners that cause bridging in metering devices. The curvature radius is specifically controlled to be less than half the face distance, maintaining cubic geometry while improving flow characteristics through automated loading equipment

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Ease of operation

If spherical shot is used, then flow characteristics are good, but packing density is low and terminal performance is reduced

Engineering Contradiction:

Improveflow characteristicsVSAvoidpacking density

Core Design Contradiction:

Ease of operationVSQuantity of substance

Solution Approach 1:

The patent creates a hybrid shape that retains the cubic form factor for high packing density while adding edge curvature to improve flow characteristics. This intermediate geometry combines the advantages of both spherical and cubic shot, achieving superior packing density with acceptable flow properties

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentEP2686635B1Rounded cubic shot and shotshells loaded with rounded cubic shot

Publication Date: 2016.03.09 OLIN CORP

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AI summary

A shot pellet for a shotshell. The shot pellet has a generally cubic shape comprising six generally square faces joined by rounded edges that have a radius of curvature of between about 15% and 40% of the distance between opposite faces of the generally cubic shaped pellet.