Recessed Shank Structure for Long-Insert Replaceable Cutting Tools

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Solution Overview

Problem

Conventional head replaceable type cutting tools face challenges in achieving better cutting performance when using cutting inserts with longer total lengths, as the increased projection of the head from the shank leads to deflection and increased moments on the fastening mechanism, causing interference and affecting cutting performance.

Innovation Solution

A shank with a recessed part at the leading end to accommodate part of the cutting insert, avoiding interference and allowing the head to be attached without increasing the projection amount, thus reducing deflection and moment on the fastening mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the projection amount of the head from the shank is increased to accommodate long cutting inserts, then the cutting insert can be held without interference, but the distance between the cutting point and the fastening mechanism increases, causing head deflection and increased moment on the fastening mechanism

Engineering Contradiction:
Improvetotal chip length of cutting insertVSAvoidcutting performance
Core Design Contradiction:
Length of moving objectVSStability of the object's composition

Solution Approach 1:

The invention introduces a recessed part that extends in the width direction (lateral dimension) of the shank to accommodate the cutting insert. This dimensional approach allows the insert to be held without increasing the longitudinal projection of the head, thereby maintaining cutting performance while accommodating longer inserts through lateral space utilization rather than longitudinal extension

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The recessed part is formed within the shank structure itself, creating a nested configuration where the cutting insert is accommodated inside the recessed portion of the shank. This nesting approach allows the insert to be held without protruding beyond the normal head projection, avoiding the need to increase the distance from the cutting point to the fastening mechanism

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If the projection amount of the head from the shank is increased to avoid interference with the cutting insert, then the cutting insert can be held, but the moment acting on the fastening mechanism increases

Engineering Contradiction:
Improveability to hold cutting insertVSAvoidmoment on fastening mechanism
Core Design Contradiction:
Adaptability or versatilityVSForce

Solution Approach 1:

The recessed part utilizes the width direction (lateral dimension) of the shank to accommodate the cutting insert, rather than extending in the longitudinal direction. This dimensional shift allows the insert to be held securely without increasing the longitudinal projection, thereby maintaining the fastening mechanism's position close to the cutting point and reducing the moment arm and associated forces

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If the projection amount of the head from the shank is increased to separate the fastening mechanism and cutting insert, then interference is avoided, but head deflection increases

Engineering Contradiction:
Improveseparation of fastening mechanism and insertVSAvoidhead rigidity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The recessed part is formed by removing material in the width direction from the shank, creating lateral separation between the fastening mechanism and the cutting insert. This lateral separation achieves the necessary clearance to avoid interference while maintaining the head's longitudinal rigidity, as the head structure itself is not extended in the critical loading direction

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The recessed part is localized to a specific region of the shank, creating a local modification that provides the necessary clearance for the cutting insert. This localized approach allows the rest of the head structure to maintain its original rigid configuration, preserving overall head strength while providing the necessary separation in the local region where the insert is held

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4295979A1Shank and cutting tool having the shank
Publication Date: 2023.12.27 TUNGALOY CORP
  • EP4295979A1 patent drawingFigure 1
  • EP4295979A1 patent drawingFigure 2
  • EP4295979A1 patent drawingFigure 3

AI summary

The present invention can realize better cutting performance while suppressing an influence of, for instance, deflection of a head and an increase in a moment acting on a fastening mechanism even when a cutting insert of a long total length is used. A shank of a head replaceable type cutting tool includes: a fastening mechanism that is formed at a leading end part in a longitudinal direction of the shank, and attaches a head; and a recessed part that is formed at the leading end part so as to accommodate a part of a cutting insert held by the head and avoid an interference with the cutting insert. The recessed part may be provided to accommodate a non-use part of the cutting insert held by the head in a state where the head is attached to the leading end part, and avoid an interference with the cutting insert.