Sleeved Tool Holder Structure to Preserve Tool Insertion Diameter

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Solution Overview

Problem

The tool holder's inner diameter decreases due to the holding force, making it difficult to insert tools with smaller diameters.

Innovation Solution

The tool holder incorporates an extended chamber that communicates with the pressurizing chamber, which curtails the radially inward elastic deformation of the inner peripheral surface, maintaining the inner diameter of the tool insertion space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the width in the radial direction of the tool holder is reduced to accommodate smaller diameter tools, then the tool holder can hold smaller tools, but the inner peripheral surface is more liable to elastically deform radially inward under pressing force, making tool insertion difficult

Engineering Contradiction:
Improveability to hold smaller diameter toolsVSAvoidease of tool insertion
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The tool holder is divided into multiple functional segments: a body member, a sleeve, and multiple grip parts with pressurizing chambers. This segmentation allows each component to perform its specific function - the body member provides structural support, the sleeve defines the tool insertion space, and the grip parts provide localized holding force. By distributing the holding function across multiple segments rather than relying on uniform radial compression, the inner peripheral surface is protected from excessive elastic deformation while maintaining the ability to hold smaller tools.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The grip parts are designed with different properties from the main body - they are thin-walled and elastically deformable in the radial direction, while the body member maintains sufficient radial width for structural stability. This local quality differentiation allows the grip parts to exert holding force on the tool without causing the entire inner peripheral surface to deform, thus enabling small tool accommodation while preserving ease of insertion.

Inventive Principle:
Principle #3Local quality

2Volume of moving object

If the radial width of the tool holder is reduced, then smaller tools can be accommodated, but the pressing force from fastening screws causes greater elastic deformation of the inner peripheral surface, decreasing the inner diameter of the tool insertion space

Engineering Contradiction:
Improvesize of tool insertion spaceVSAvoidresistance to elastic deformation
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The sleeve acts as an intermediary component between the body member and the tool. It transmits the holding force from the grip parts to the tool while protecting the inner peripheral surface from direct contact with fastening screw pressing forces. The sleeve's structural design allows it to maintain the inner diameter of the tool insertion space even when the body member undergoes elastic deformation under external pressing force.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The tool holder employs a composite structure combining a body member with sufficient radial width for strength and a sleeve with optimized wall thickness for minimal deformation. This composite design allows the outer structure to withstand pressing forces while the inner structure maintains its dimensional stability, preventing excessive decrease in the inner diameter of the tool insertion space.

Inventive Principle:
Principle #40Composite materials

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 configuration prevents a decrease in the inner diameter of the tool insertion space, ensuring easy insertion and use of tools with smaller diameters.

Implementation Method 1

By increasing the pressure in the pressurizing chamber, the grip part elastically deforms radially inward

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4238677B1Tool holder
Publication Date: 2025.02.26 NT TOOL CORP
  • EP4238677B1 patent drawingFigure 1
  • EP4238677B1 patent drawingFigure 2
  • EP4238677B1 patent drawingFigure 3

AI summary

[Object] To provide a technique that can curtail a decrease of an inner diameter of a tool insertion space by a force that holds a tool holder. [Solution] Pressurizing chambers 123a, 123b are formed between a body member inner peripheral surface 111 of a body member 110 and a sleeve outer peripheral surface 122 of a sleeve 120. Grip parts 124a, 124b are formed between the sleeve outer peripheral surface 122 and a sleeve inner peripheral surface 121 and are elastically deformed radially inward by an increase of pressure in the pressurizing chambers 123a, 123b. An extended chamber 123d is formed between the sleeve outer peripheral surface 122 and the body member inner peripheral surface 111 and communicates with a rear end part of the pressurizing chamber 123a and extends in an axial direction and in a circumferential direction. The extended chamber 123d is configured such that radially inward elastic deformation (decrease of an inner diameter of a sleeve interior space 120a forming a tool insertion space) of a portion of the body member inner peripheral surface 121, which corresponds to a grip part 124a, by a pressing force received on a body member outer peripheral surface 112 is curtailed.