Hand Tool Deformable Tooth-Shaped Connection Interface

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Solution Overview

Problem

Existing hand tools, such as scrapers and screwdrivers, suffer from unreliable connections between the working unit and the knocking unit, leading to excessive impact force being transferred to the handle, causing damage due to limitations in production precision and assembly design.

Innovation Solution

A hand tool design featuring a deformable and non-rigid contacting surface between the working unit and the knocking unit, with a tooth-shaped configuration that allows for gapless engagement, along with a connecting unit like a pin or rivet, to ensure reliable and fixed connections, dispersing impact force effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a knocking unit is directly connected to the handle, then the impact force can be transferred to the handle via the knocking unit, but the handle is still damaged due to the direct transmission of impact force

Engineering Contradiction:
Improveconnection reliabilityVSAvoidhandle strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent introduces a buffer zone between the knocking unit and handle, and uses elastic deformation of the contacting surface to absorb impact energy before it reaches the handle, preventing direct transmission of impact force that would damage the handle

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent introduces an intermediate contacting surface with deformable structure between the knocking unit and handle. This intermediary component absorbs and distributes impact forces through elastic deformation, preventing direct force transmission to the handle while maintaining connection reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple limiting parts are used in the assembly to achieve precise engagement, then the connection between working unit and knocking unit can be improved, but the production cost increases undoubtedly

Engineering Contradiction:
Improveconnection reliabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the physical state of the contacting surface from rigid to deformable, allowing it to dynamically adjust its shape during impact. This parameter change enables the surface to accommodate manufacturing tolerances and achieve reliable connection without requiring multiple limiting parts or high precision manufacturing

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent makes the contacting surface dynamic by giving it elastic deformation capability. The surface deforms under impact load to ensure proper engagement, then returns to its original shape. This dynamic behavior compensates for manufacturing variations and eliminates the need for complex limiting mechanisms

Inventive Principle:
Principle #15Dynamics

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

This design reduces the impact force transferred to the handle, prolonging its service life and lowering production precision requirements, while maintaining reliable connections between the working unit and knocking unit, thus enhancing the tool's durability and efficiency.

Implementation Method 1

The connecting part between the knocking unit of the hand tool of the present disclosure and the handle end of the working unit is a contacting surface, the handle end or the contacting surface being configured as a deformable and non-rigid contact

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3254810B1Manual tool having reliable connection
Publication Date: 2020.03.25 HANGZHOU GREAT STAR TOOLS
  • EP3254810B1 patent drawingFigure 1~5
  • EP3254810B1 patent drawingFigure 4~7
  • EP3254810B1 patent drawingFigure 8~11

AI summary

The present invention provides a hand tool with reliable connections comprising: a working unit having a working end and a handle end opposite to the working end; a handle being mounted on the handle end of the working unit and having a working unit end and a knocking unit end; a knocking unit being mounted on the knocking unit end of the handle. The connecting part between the knocking unit and the handle end of the working unit is a contacting surface, the handle end or the contacting surface is configured as a deformable and non-rigid contact, realizing the reliable connection between the working unit and the knocking unit. The deformable and non-rigid contact is realized by the configuration of at least one of the contacting surface and the handle end being configured to be tooth-shaped, the tooth-shape can deform and form a gapless engagement with the contacting surface. This configuration lowers the precision requirements for the production of each part; saves the costs; achieves reliable connections among the working unit, knocking unit and the handle of the hand tool; and disperses the impact force that damages the handle.