Impact Rotary Tool Attachment With Thinner Coupling Shaft for Easy Removal

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Solution Overview

Problem

There is a growing demand for an impact rotary tool attachment that is easily removable from an impact rotary tool.

Innovation Solution

The impact rotary tool attachment features a coupling shaft with an input part that is thinner than the output part, allowing it to be easily inserted and removed from the impact rotary tool, and includes recesses to reduce contact with steel balls, facilitating easy detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the coupling shaft has a uniform thickness, then the structural strength is maintained, but the attachment becomes difficult to remove from the impact rotary tool

Engineering Contradiction:
ImproveEase of removalVSAvoidStructural strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The coupling shaft is divided into two distinct sections: a thicker output part for strength and a thinner input part for easy removal. This segmentation allows each part to fulfill its specific function - the output part maintains structural integrity while the input part enables convenient detachment from the impact rotary tool.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different thicknesses are applied to different parts of the coupling shaft based on local requirements. The output part has greater thickness for strength where it connects to the attachment, while the input part has reduced thickness specifically where it interfaces with the impact rotary tool, allowing easy removal. This local differentiation of properties resolves the contradiction between strength and ease of removal.

Inventive Principle:
Principle #3Local quality

2Reliability

If the coupling shaft contacts the steel balls, then the attachment mechanism functions properly, but the steel balls may be damaged during removal

Engineering Contradiction:
ImproveAttachment mechanism reliabilityVSAvoidDamage risk to steel balls
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The thinner input part of the coupling shaft is designed to be inserted and removed through the steel balls without contacting them excessively. This preliminary design of the shaft geometry prevents harmful contact during the removal process, allowing the attachment mechanism to function reliably during operation while protecting the steel balls from damage during maintenance operations.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the attachment is tightly secured, then the operational stability is improved, but the removal process becomes difficult

Engineering Contradiction:
ImproveOperational stabilityVSAvoidEase of removal
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The coupling shaft's segmented design with different thicknesses allows the attachment to be tightly secured during operation through the thicker output part, while the thinner input part enables easy removal. This segmentation creates a differential engagement system where stability and ease of removal are achieved in different sections of the same component.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3978192B1Attachment for impact rotary tools and tool system
Publication Date: 2025.09.24 PANASONIC HOLDINGS CORP
  • EP3978192B1 patent drawingFigure 1
  • EP3978192B1 patent drawingFigure 2
  • EP3978192B1 patent drawingFigure 3

AI summary

The problem to be overcome by the present disclosure is to provide an impact rotary tool attachment, which is easily removable from an impact rotary tool, and a tool system including such an impact rotary tool attachment. An impact rotary tool attachment (7; 7a; 7b; 7c) according to the present disclosure includes a coupling shaft (72) and an input shaft (71). The coupling shaft (72) is inserted into an insert hole (62) of an impact rotary tool (1), faces each of a plurality of spherical members, and receives rotational driving force transmitted from the impact rotary tool (1). The input shaft (71) receives the rotational driving force transmitted via the coupling shaft (72). The coupling shaft (72) includes an input part (721) and an output part (722). The input part (721) includes a thinner shaft portion (723). The thinner shaft portion (723) includes a part thinner than the output part (722) in at least a range from a position where the thinner shaft portion (723) faces the plurality of spherical members to a tip thereof located closer to the impact rotary tool (1).