Indexable Insert Tool Clamping Screw Inclination

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Solution Overview

Problem

Existing insert-indexable tools face issues with inconsistent contact between the clamping screw's pressing portion and the spot facing, leading to variable clamping force and potential misalignment of the insert, due to coinciding axes of the threaded hole and spot facing, resulting in unreliable clamping.

Innovation Solution

The insert-indexable tool design features obliquely intersecting axes of the spot facing and threaded hole, ensuring the clamping screw contacts the spot facing at a minimum gap and appropriate position, with the clamping screw inclined relative to the insert mount seat, and the head member fixed using separate fixing screws to prioritize the clamped state, eliminating variation in contact position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the threaded hole and spot facing have coinciding axes, then the structure is simple and easy to manufacture, but the contact position between the clamping screw and spot facing varies leading to unreliable clamping

Engineering Contradiction:
Improveease of manufactureVSAvoidclamping reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies asymmetry by deliberately designing the threaded hole axis and spot facing center axis to be non-coincident (offset by a specific distance). This asymmetric configuration ensures that the clamping screw consistently contacts the spot facing at a predetermined position, eliminating the variability caused by coinciding axes while maintaining manufacturing feasibility through precise dimensional specifications.

Inventive Principle:
Principle #4Asymmetry

2Device complexity

If the clamping screw is used to fix both the head member and clamp the insert, then the device structure is simple, but the contact position variation causes jaw deformation and misalignment

Engineering Contradiction:
Improvedevice complexityVSAvoidinsert alignment precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent segments the functions by separating the head member fixation from the insert clamping operation. The head member is fixed to the holder using dedicated fixing screws, while the clamping screw's sole function is to clamp the insert by pressing the spot facing. This functional segmentation eliminates the interference between fixation and clamping operations, preventing jaw deformation and ensuring precise insert alignment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the fixation function from the clamping screw by providing separate fixing screws for the head member. This extraction allows the clamping screw to focus exclusively on the clamping operation, eliminating the source of variability and deformation that occurred when a single screw performed both fixation and clamping functions.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If the pressing portion contacts the spot facing at positions with tangential vector away from the holder, then the structure is simple, but the jaw deforms away from the holder causing insert misalignment

Engineering Contradiction:
Improvedevice complexityVSAvoidinsert positioning accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating a specific local geometric relationship between the threaded hole axis and spot facing center axis. The offset distance is precisely controlled to ensure that the contact point between the clamping screw and spot facing generates a pressing force directed toward the holder. This localized geometric control ensures consistent and accurate insert positioning while maintaining overall structural simplicity.

Inventive Principle:
Principle #3Local quality

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 ensures reliable clamping of the insert by maintaining consistent contact between the clamping screw and spot facing, preventing jaw deformation and misalignment, and allowing for firm fixation of the insert without relying on the clamping screw for head member fixation.

Implementation Method 1

one of the pair of jaws of the head member is provided with a spot facing. The threaded hole and the spot facing have a common axis, and the common axis is oriented so as to be inclined with respect to intersecting axes of a front face and the side faces of the holder, i.e., so as to be inclined with respect to the clamping direction of the insert mount seat. In the insert-indexable tool, the insert is clamped by screwing the clamping screw so as to fix the head member while being drawn toward the holder, and by pressing the spot facing by the pressing portion of the clamping screw to elastically move one of the pair of jaws in the clamping direction.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP1872887B1Tool with indexable insert
Publication Date: 2010.09.15 MITSUBISHI MATERIALS CORP
  • EP1872887B1 patent drawingFigure 1~2
  • EP1872887B1 patent drawingFigure 3
  • EP1872887B1 patent drawingFigure 4~5

AI summary

An insert-indexable tool includes: a holder (10); and a head member (30) having an insert mount seat (36) by which an insert (60) having a cutting edge (62) is to be clamped, and mounted on a distal portion of the holder (10), wherein the head member (30) includes a first jaw (32) having a clamping face (34) and a second jaw (33) having a base face (35), the clamping face (34) and the base face (35) opposing each other so as to constitute the insert mount seat (36), a clamping screw (50) having a shaft portion (51) and a pressing portion (52) is disposed in the distal portion of the holder (10) in such a manner that, in a view facing toward the distal portion of the holder (10) along an extending direction of the insert mount seat (36), the clamping screw (50) is inclined with respect to the extending direction of the insert mount seat (36) and extends gradually toward an inside of the holder (10) while extending from the first jaw (32) toward the second jaw (33), the holder (10) is provided with a threaded hole (22) engageable with the shaft portion (51) of the clamping screw (50), the first jaw (32) is provided with a spot facing (45) accommodating the pressing portion (52) of the clamping screw (50), and a center axis (C) of the spot facing (45) and an axis (M) of threaded hole (22) obliquely intersect each other.