Mid Lock-Up Receiver Design with Segmented Lug Ways

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Mid lock-up receivers in firearms are challenging to manufacture economically due to the need for lug ways that run the full length of the receiver, resulting in a less rigid design and perceived accuracy disadvantages compared to rear lock-up receivers.

Innovation Solution

A mid lock-up receiver design featuring an elongated body with a first and second passage segment of different diameters, an insert sleeve that is thermally bonded to the body, and radiused bolt lugs that eliminate the need for costly EDM machining, allowing for lower-cost production and increased accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If mid lock-up receiver design is used, then rifle accuracy is improved, but manufacturing cost and complexity increase

Engineering Contradiction:

Improverifle accuracyVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The receiver is divided into two distinct segments: a rear portion and a forward portion, separated by a transverse abutment. The lug ways are confined to the rear portion and terminate at the abutment, while the forward portion has a different internal geometry. This segmentation allows the lug ways to provide mid-lock-up support without running the full length of the receiver, reducing manufacturing complexity while maintaining accuracy benefits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The receiver structure is optimized locally at different positions. The rear portion contains the lug ways with radiused bolt lugs for mid-lock-up engagement, while the forward portion has a simplified internal structure without continuing lug ways. This local differentiation provides the necessary locking support where needed while eliminating unnecessary material and machining in the forward section, reducing overall manufacturing cost.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If lug ways run the full length of the receiver, then manufacturing is simpler, but receiver rigidity and accuracy support deteriorate

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidreceiver rigidity

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The lug ways are extracted from the forward portion of the receiver and confined to the rear portion only. The lug ways terminate at the transverse abutment, removing the problematic continuation of lug ways into the forward portion. This extraction eliminates the source of rigidity problems while maintaining the manufacturing simplicity of having lug ways in the rear section.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of having lug ways run continuously from rear to front as in conventional designs, the invention inverts the approach by having lug ways terminate at the abutment and not continue forward. The forward portion is designed with a different internal geometry that does not require lug way continuation, thus improving rigidity while maintaining manufacturability.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of manufacture

If radiused bolt lugs are used, then EDM machining costs are reduced, but manufacturing precision requirements increase

Engineering Contradiction:

ImproveEDM machining costVSAvoidlug geometry precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The bolt lugs are designed with radiused (curved) surfaces instead of sharp corners or complex geometries that would require expensive EDM machining. The radiused configuration allows the lugs to be manufactured using conventional machining methods, significantly reducing EDM costs. The curved surfaces also provide better stress distribution and are easier to machine with standard tools while maintaining functional precision.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 design enables the production of a mid lock-up receiver that is more accurate and cost-effective than prior art, with radiused lug ways terminating at the midpoint, providing improved rigidity and accuracy while reducing manufacturing complexity and costs.

Implementation Method 1

The sleeve may be thermally bonded to the body

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10907915B2Mid lock-up receiver

Publication Date: 2021.02.02 VUDOO OUTDOORS GROUP LLC

AI summary

Mid lock-up receivers have an elongated body, the body defining a passage, the body having a first rear portion and a second forward portion adjacent to and forward of the rear portion, the first rear portion defining a first passage segment having a first diameter and the second forward portion defining a second passage segment having a second diameter greater than the first diameter, a stop surface defined at a forward end of the first rear portion, an elongated sleeve defining a sleeve passage and received in the second passage segment, the sleeve having a rear-facing limit surface spaced apart from the stop surface, and the sleeve being compressively received in the body wherein the body is in tension about the sleeve, and the sleeve is compressed by the body. The sleeve may be thermally bonded to the body.