Cartridge Case Preparation Rotor with Flexuous Alignment

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Solution Overview

Problem

Existing devices for trimming and preparing brass cartridge cases often result in inaccurate cuts due to the case being held stationary, leading to crooked necks, wobble, and banana cases, which affect the accuracy of fired bullets, and require tedious adjustments and multiple handling steps.

Innovation Solution

A bench-top machine with a rotating case holder and a rotor-mounted tool system that aligns tools with the case axis, allowing for simultaneous trimming, chamfering, deburring, and cleaning, using a variable speed electric motor and interchangeable tools for different calibers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the case is held stationary and the trimmer is turned, then the trimming operation can be performed, but the case neck may be trimmed at a slight angle if the case is not held precisely straight

Engineering Contradiction:

Improvecase neck trimming accuracyVSAvoidcase holding difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

Instead of holding the case stationary and turning the trimmer, the invention inverts the approach by turning the case against a stationary trimmer. The case is rotated in a chuck while the trimmer blade remains fixed, which simplifies case holding and improves trimming accuracy by eliminating the need to precisely align a stationary case with a moving tool.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention introduces a pilot inserted into the case neck as an intermediary element. This pilot serves as a reference axis that guides the case during rotation and ensures the case neck remains aligned with the stationary trimmer blade, thereby preventing crooked cuts while simplifying the holding operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple tools revolve and each case is brought to each spinning tool by hand, then trimming, chamfering, and deburring can be performed, but the case mouth may become crooked due to manual alignment difficulty

Engineering Contradiction:

Improvemultiple operation capabilityVSAvoidcase mouth alignment accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention inverts the traditional approach by having a single case rotate through multiple stationary tools rather than bringing multiple revolving tools to each case. The case is mounted in a chuck and rotated while passing sequentially past a trimmer, chamfering tool, and deburring tool, all of which remain stationary. This eliminates manual alignment errors and ensures consistent precision across all operations.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The rotating case setup serves multiple functions: it enables sequential trimming, chamfering, and deburring operations in a single setup. The case rotation mechanism universally accommodates all tool interactions, eliminating the need for separate alignment operations for each tool and ensuring consistent accuracy across all case mouth preparations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Manufacturing precision

If the case is turned against a stationary trimmer with a pilot, then trimming accuracy improves, but the device complexity increases due to required pilots and dies for each caliber

Engineering Contradiction:

Improvecase neck trimming accuracyVSAvoidcaliber-specific components

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention makes the case holder and chuck system universal by designing them to accommodate various cartridge calibers without requiring caliber-specific pilots or dies. The case holder grips the case head universally, and the case itself serves as the reference axis, eliminating the need for separate alignment components for each caliber while maintaining high trimming accuracy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Ease of operation

If manual handling is performed for each case preparation step, then flexibility is maintained, but productivity decreases due to repeated handling and fatigue

Engineering Contradiction:

Improveoperational flexibilityVSAvoidcase preparation throughput

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The invention enables continuous operation by having the case rotate automatically through all preparation steps (trimming, chamfering, deburring) in a single continuous motion. The case is mounted once in the chuck and then sequentially passes all stationary tools without removal or repositioning, eliminating repeated handling and operator fatigue while maintaining operational flexibility.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS9970741B1Cartridge case preparation rotor device

Publication Date: 2018.05.15 ELDREDGE ERIC P

AI summary

The cartridge case preparation rotor device trims cartridge cases to overall length correctly and further prepares them for reloading. The rotor holds multiple case preparation tools so that the user may conveniently and precisely apply them more squarely to a turning cartridge case. The rotor slides and turns on a rod mounted opposite a variable speed motor fitted with a chuck turning a case holder. Flexibility of the rod and oscillation of the rotor permit each tool to follow case eccentricity. An enlarged grip on the case holder simplifies installation and removal of cases. A neck cleaning tool cleans the inside and outside of the case neck simultaneously. The rotor may be slid along and turned upon the rod manually, or the motor and rotor can be mounted on a progressive press. The pushbutton control switch can be pressed by hand, or set on the floor as a foot switch.