Rotatable Cutting Tool Key Surfaces That Prevent Axial Slippage

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Solution Overview

Problem

Existing rotatable machining tools face issues with key attachment surface formations that can slip axially, leading to potential damage to the cutting edge during torque introduction, as the current flat key attack surfaces are not optimally designed for secure engagement.

Innovation Solution

The introduction of non-parallel contact surfaces with complementary key surfaces, including curved and flat surfaces, that provide a larger contact area and secure axial engagement, preventing slipping and enhancing torque transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If flat parallel key engagement surfaces are used, then the structure is simple and easy to manufacture, but axial slippage occurs during torque application causing damage to cutting edges

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies curvature by replacing the traditional flat parallel key engagement surfaces with at least one curved key engagement surface that is inclined relative to the tool axis. This curved surface prevents axial slippage of the wrench during torque application while maintaining ease of manufacture through standard machining operations.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters of the key engagement surface by inclining it at a specific angle (5° to 45°) relative to the tool axis. This parameter change transforms the surface from a flat parallel configuration to an inclined curved configuration, providing axial positioning functionality while preserving manufacturing simplicity.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If flat parallel key engagement surfaces are used, then manufacturing complexity is low, but the contact area is insufficient leading to slippage and potential damage

Engineering Contradiction:
Improvedevice complexityVSAvoidcontact area
Core Design Contradiction:
Device complexityVSArea of stationary object

Solution Approach 1:

The curved key engagement surface increases the effective contact area between the wrench and the tool compared to flat surfaces. The curvature allows for a larger surface area engagement while maintaining low device complexity through straightforward machining processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent introduces a new dimensional aspect by inclining the key engagement surface relative to the tool axis. This creates a three-dimensional engagement geometry that increases contact area without significantly increasing overall device complexity, as the inclination can be achieved through standard machining.

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

3Reliability

If the key engagement surface is inclined relative to the tool axis, then axial positioning is improved preventing slippage, but manufacturing precision requirements increase

Engineering Contradiction:
Improveaxial positioningVSAvoidmanufacturing precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent specifies a practical range for the inclination angle (5° to 45°) that optimizes axial positioning while considering manufacturing capabilities. This parameter range provides sufficient axial constraint to prevent slippage during torque application without imposing excessively tight manufacturing precision requirements.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3124149B1Rotatable machining tool having an axial securing element for key and key
Publication Date: 2022.02.09 FRANZ HAIMER MASCHINENBAU KG
  • EP3124149B1 patent drawingFigure 1
  • EP3124149B1 patent drawingFigure 2a~2b
  • EP3124149B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a rotatable cutting tool (10), in particular a tool head (10), such as a milling, grinding or drilling head, which extends along a tool axis (W) defining an axial direction, wherein the cutting tool (10) has a cutting formation (13) in a first axial longitudinal end region (12) which is designed for material removal from a workpiece, wherein the cutting tool (10) has a screw connection formation in a second axial longitudinal end region (18) opposite the first, which is designed for screw connection with a coupling component, such as a shank component, tool holder (24) and/or chuck, and wherein the cutting tool (10) has key engagement surface formations (30, 36) diametrically opposed to each other with respect to the tool axis (W), which are designed for torque-transmitting contact engagement with key surfaces of a torque wrench.According to the invention, at least one key attack surface formation (30, 36) has at least one axial locking formation (31, 33) which comprises at least one contact surface that is not parallel to the tool axis (W).