Handle Assembly System with Trapezoidal Thread Friction Joint

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Solution Overview

Problem

Existing handle assembly systems for long hand tools, such as pruners, are complex and fragile due to their multi-part disengageable designs, making them difficult to assemble and disassemble efficiently for storage and use.

Innovation Solution

A handle assembly system utilizing trapezoidal threads and complementary cylindrical portions between sleeve sections, with a friction seal and bearing surfaces, to securely connect and absorb forces between handle sections, allowing for robust and simple assembly and disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If stop-type or buttress-type securing methods are used to allow disassembly for storage, then handle sections can be separated, but the assembly system becomes complex and fragile with numerous parts

Engineering Contradiction:
Improvedisassembly capabilityVSAvoidassembly system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The handle assembly is divided into multiple sections that can be separated for storage and reassembled for use. Each section contains specific structural elements (bearing surfaces, threads, cylindrical portions) that enable both secure connection during use and controlled disassembly for storage, resolving the contradiction between adaptability and complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

One handle section is inserted into another handle section, with the inner section having a recess that receives the outer section. This nested arrangement allows compact storage while maintaining secure connection during use through the bearing surfaces and threading mechanisms, reducing the need for additional complex securing parts

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If disengageable devices are used to allow intentional disassembly, then handle sections can be separated for storage, but the system becomes fragile and complex

Engineering Contradiction:
Improvedisassembly easeVSAvoidassembly reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The bearing surfaces and threading mechanisms are pre-configured during manufacturing to enable both secure connection and controlled disassembly. The recesses, bearing surfaces, and threads are prepared in advance to work together, allowing reliable assembly during use while enabling easy intentional disassembly when needed, improving both reliability and ease of operation

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If multiple parts are used in the assembly system to enable disassembly, then handle sections can be separated, but the system becomes complex and difficult to assemble

Engineering Contradiction:
Improvestorage capabilityVSAvoidassembly simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Multiple functions are merged into integrated structural elements. The bearing surfaces, threads, and cylindrical portions are combined into unified components that simultaneously provide secure connection, controlled disassembly, and structural integrity. This merging reduces the number of separate parts and simplifies both manufacturing and assembly operations while maintaining storage capability

Inventive Principle:
Principle #5Merging (Combining)

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 system provides a robust and simple method for assembling handle sections, ensuring secure connection and efficient force transmission, while allowing for easy disassembly for storage, without compromising the tool's functionality during use.

Implementation Method 1

The thread is trapezoidal... The means for transferring force are positioned between the assembly's securing means and the retaining means

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

A friction seal 51 extends radially and centrifugally from the external lateral wall

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3112091B1System for handle assembly for a hand tool
Publication Date: 2023.01.11 PRUNING SHEARS PRADINES
  • EP3112091B1 patent drawingFigure 1

AI summary

The sleeve assembly system (1) comprises first (3) and second (5) sleeve sections intended to be assembled with each other, means for retaining one of the first and second sleeve sections in the other of the first and second sleeve sections and means for securing by friction (31,51,55) an assembly of the first and second sleeve sections, the means for securing by friction comprising a friction joint (51) interposed between the first and second sleeve sections.