Tool Holder Drawing Screw Segmentation and Inversion

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Solution Overview

Problem

Conventional tool holders face issues with the stopper member loosening and reduced rigidity of the drawing screw, especially when the tool length is longer, leading to improper chucking of the tapered collet and increased processing time and cost.

Innovation Solution

A tool holder design with a rear hole, intermediate hole, and collet holding hole, where the drawing screw is inserted from the top end, featuring a boundary wall surface to prevent rearward movement and a stopper member positioned between the drawing screw and intermediate hole to limit movement, along with a side lock member for secure assembly, reducing the overall length and maintaining rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the tool length of the tool holder is longer than that of typical tool holders, then the processing capability is improved, but the drawing screw requires a deep hole drilling process which increases processing time and cost

Engineering Contradiction:

Improvetool lengthVSAvoidprocessing time

Core Design Contradiction:

Length of moving objectVSLoss of time

Solution Approach 1:

The hole structure is segmented into three parts: rear hole, intermediate hole, and collet holding hole. This segmentation allows the drawing screw to be inserted from the top end through the collet holding hole and intermediate hole, avoiding the need for deep hole drilling from the rear end, thereby reducing processing time and cost while maintaining the capability for longer tool lengths.

Inventive Principle:

Principle #1Segmentation

2Length of moving object

If the tool length of the tool holder is longer than that of typical tool holders, then the processing capability is improved, but the drawing screw length increases thereby reducing rigidity

Engineering Contradiction:

Improvetool lengthVSAvoidrigidity of drawing screw

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Device complexity

If the same drilling process for the drawing screw is used as that used in tool holders having a short tool length, then the processing method is simplified, but the length of the drawing screw is increased thereby reducing rigidity

Engineering Contradiction:

Improveprocessing methodVSAvoidrigidity of drawing screw

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

4Ease of manufacture

If the drawing screw is inserted from the rear end opening, then the assembly process follows conventional methods, but the head of the drawing screw requires a slip seat and stopper member to limit movement

Engineering Contradiction:

Improveassembly processVSAvoidnumber of components

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The drawing screw insertion direction is inverted from the conventional rear end opening to the top end opening through the collet holding hole. This inversion eliminates the need for slip seats and stopper members to limit rearward movement, as the boundary wall surface naturally limits the drawing screw movement, thereby simplifying the assembly process and reducing component count.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS8714893B2Tool holder and method for assembling the same

Publication Date: 2014.05.06 NIKKEN KOSAKUSHO WORKS LTD

AI summary

A tool holder includes a drawing screw and a stopper member. The drawing screw is positioned in an intermediate hole. A rear end face of a head of the drawing screw faces a boundary wall surface, and a top end of a shaft of the drawing screw is screwed in a rear end of a collet. The stopper member is positioned in an annular space between an outer peripheral surface of the shaft of the drawing screw and an inner peripheral surface of the intermediate hole. The stopper member faces a front end face of the head of the drawing screw, and limits movement of the head toward a top end of the tool holder. The drawing screw and the stopper member are inserted and assembled from a top end opening of a collet holding hole.