Shotgun Ejector Assembly With TAG Mounting for Field Repair

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The REMINGTON® MODEL 870® pump action shotgun ejector mechanism is prone to breakage due to repeated use and misalignment, making field repairs difficult and requiring specialized tools, which often result in improper alignment and further damage.

Innovation Solution

A tongue-and-groove (TAG) ejector assembly that uses screws instead of rivets to secure the spring to the receiver, eliminating the need for staking through the spring and allowing easy field repairs without specialized tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rivets are used to affix the ejector to the receiver, then the ejector is securely mounted, but field repair becomes difficult and requires specialized tools

Engineering Contradiction:

Improvemounting strengthVSAvoidfield repairability

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

The ejector assembly is divided into separable components (ejector body, spring, rivets) that can be independently removed and replaced. The rivets serve as detachable fasteners that allow the ejector to be segmented from the receiver for repair purposes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The rivets are designed as inexpensive, easily replaceable fasteners. Rather than attempting to repair the entire ejector assembly in the field, the solution allows for simple replacement of consumable parts (rivets, spring) to restore functionality.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Strength

If the spring is staked through the base and receiver, then the ejector structure is reinforced, but misalignment causes catastrophic failure

Engineering Contradiction:

Improvestructural strengthVSAvoidalignment tolerance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The design incorporates alignment features and tolerances that prevent misalignment from causing catastrophic failure. The spring and base are configured to accommodate minor misalignments before operation, cushioning against the harmful effects of improper assembly.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The base acts as an intermediary component between the receiver and spring, providing a mounting surface that distributes stress and accommodates alignment variations. This intermediate structure prevents direct transmission of misalignment stresses to the spring.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If the spring is riveted through the base, then the components are securely fastened, but the spring is vulnerable to warping and breaking

Engineering Contradiction:

Improvefastening strengthVSAvoidspring durability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The spring is extracted from the riveting process entirely. Rather than punching holes through the spring and fastening it with rivets, the spring is retained by friction fit or deformation of the base structure, eliminating the harmful extraction of material from the spring.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The design converts the potential harm of spring stress concentration (from rivet holes) into a benefit by using a rivetless construction. The spring remains intact without holes, and the fastening method actually improves spring durability by avoiding stress concentration points.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Adaptability or versatility

If conventional ejector replacement kits are used, then replacement parts are available, but specialized tools and expertise are required

Engineering Contradiction:

Improveparts availabilityVSAvoidtool requirement

Core Design Contradiction:

Adaptability or versatilityVSEase of repair

Solution Approach 1:

The ejector components are designed with universal, standard fasteners (rivets) that can be replaced with common tools. The design accommodates multiple repair scenarios (field repair, shop repair, complete replacement) using the same basic component interface.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The ejector is designed to be repairable by the end user without requiring specialized tools or expertise. The simple rivet and spring construction allows users to perform their own maintenance and repairs using basic hand tools.

Inventive Principle:

Principle #25Self-service

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 TAG ejector assembly reduces the vulnerability to warping and breakage, simplifying repairs and maintaining the shotgun's functionality with improved alignment and durability.

Implementation Method 1

The TAG ejector assembly comprises a TAG spring and a TAG base. The TAG spring is adapted and configured to engage with the TAG base in a tongue-and-groove (TAG) configuration when the TAG ejector assembly is affixed to the interior surface of the MODEL 870® receiver

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS12480727B1Ejector kits, assemblies, and methods of use

Publication Date: 2025.11.25 WEAPONS ARMORER INC

AI summary

Kits for replacing the ejector of a shotgun include an ejector spring and a base member, where the base member is designed and adapted to be affixed to the interior surface of the receiver of the shotgun, and further to engage the ejector spring in a cantilevered tongue-and-groove (TAG) configuration. TAG ejector kits, TAG ejector assemblies, and TAG ejectors are suitably configured for operation in conjunction with pump action shotguns.