Handgun Forestock Mounting via Clamping Eccentric

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Solution Overview

Problem

Existing handgun shaft attachment methods require multiple turns and complex assembly efforts, leading to time-consuming assembly and disassembly, and there is a risk of threaded screws getting lost during use.

Innovation Solution

A shaft fastening device featuring a clamping bolt and clamping eccentric that allows for quick and secure assembly and disassembly by generating an axial tensile force, requiring only a quarter turn to clamp or loosen, and includes a locking mechanism to prevent over-tightening and loss of components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If threaded screws are used to attach the shaft to the receiver, then the shaft can be securely fastened, but the assembly and disassembly process becomes time-consuming and complex

Engineering Contradiction:
Improvesecure fasteningVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The fastening system is divided into separate functional components: a clamping bolt with clamping head for securing the shaft, and a clamping eccentric with lateral slot for enabling quick rotation. This segmentation allows each component to perform its specific function efficiently, achieving secure fastening with minimal assembly steps.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clamping eccentric is designed to rotate dynamically between different positions (clamping position and release position) to control the fastening state. This dynamic mechanism allows quick transition between secured and released states with simple rotational movement, dramatically reducing assembly time while maintaining secure fastening when engaged.

Inventive Principle:
Principle #15Dynamics

2Reliability

If threaded screws are used for shaft attachment, then the shaft can be firmly fixed, but the screws are prone to getting lost during use

Engineering Contradiction:
Improvefirm fixationVSAvoidloss of fastening components
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The clamping bolt and clamping eccentric are merged into an integrated fastening assembly that remains attached to the shaft and receiver even when disassembled. The clamping eccentric stays mounted on the shaft while the clamping bolt remains on the receiver, preventing separation and loss of components during field use.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The clamping eccentric acts as an intermediary component that mediates between the clamping bolt and the shaft. It transfers the clamping force while maintaining a permanent mounting relationship with both the shaft and receiver, ensuring that no component can be lost during operation or field use.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional fastening screws are used, then the shaft can be attached to the receiver, but over-tightening and resulting inaccuracies occur

Engineering Contradiction:
Improveshaft attachmentVSAvoidshaft alignment accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The fastening mechanism changes the critical parameter from rotational threading to rotational eccentricity. The clamping eccentric rotates to generate clamping force through its eccentric geometry, allowing precise control of the clamping position and force application point, thereby preventing over-tightening and maintaining shaft alignment accuracy.

Inventive Principle:
Principle #35Parameter changes

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

Enables rapid and secure assembly and disassembly of the shaft without complex assembly work, preventing over-tightening and ensuring that the clamping components remain attached, thus reducing assembly time and minimizing the risk of lost parts.

Implementation Method 1

a clamping eccentric (4) which interacts with the clamping bolt (3) and by means of which the shaft (5) can be fastened to the breech housing (2) while generating an axial tensile force

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentEP2578985B1Forestock mounting system for a handgun
Publication Date: 2015.06.24 J P SAUER & SOHN GEGR 1751
  • EP2578985B1 patent drawingFigure 1
  • EP2578985B1 patent drawingFigure 2
  • EP2578985B1 patent drawingFigure 3

AI summary

The invention relates to a stock fastening device (1) for fixing a stock (5) to a receiver (2) of a handgun, characterized by a clamping bolt (3) and a clamping eccentric (4) cooperating with the clamping bolt (3), by which the stock (5) can be fastened to the receiver (2) by generating an axial tensile force.