Cutting Head Clamping Pin Design for Precise Torque Transfer

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Solution Overview

Problem

Existing rotary cutting tools face challenges in securely and precisely attaching a cutting head with a cutting insert to a tool shank, particularly in maintaining a stable torque transfer and precise positioning, which affects drilling accuracy and efficiency, especially in deep holes.

Innovation Solution

The design incorporates a centrally disposed locating pin with clamping recesses and a pin receptacle, along with coolant channels in fluid communication, and uses a clamping mechanism with frusto-conical shaped clamping members to securely clamp the cutting head to the tool shank, ensuring precise alignment and stable torque transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a locating pin and pin receptacle mechanism is used to position the cutting head, then positioning precision is improved, but the device complexity increases due to additional clamping components

Engineering Contradiction:
Improvepositioning precisionVSAvoidclamping mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The locating pin serves dual functions: it provides precise positioning of the cutting head and acts as a clamping element when combined with the frusto-conical clamping members. By merging the positioning and clamping functions into a single integrated mechanism, the device complexity is reduced while maintaining positioning precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locating pin is designed as a multi-functional component that simultaneously performs positioning, alignment, and clamping functions. This universal component eliminates the need for separate positioning and clamping mechanisms, thereby reducing overall device complexity while achieving precise positioning.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Force

If frusto-conical clamping members are used to clamp the cutting head, then clamping force and torque transfer are improved, but the device complexity increases due to additional clamping components

Engineering Contradiction:
Improveclamping forceVSAvoidclamping mechanism complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The frusto-conical shape of the clamping members provides curved surfaces that convert axial clamping force into radial holding force on the locating pin. This geometric curvature enables effective torque transfer and secure clamping without requiring complex multi-component mechanisms, as the conical geometry itself generates the necessary mechanical advantage.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The frusto-conical clamping members act as intermediary elements between the axial clamping force applied by the clamping device and the locating pin. These conical members transmit and transform the clamping force efficiently, providing strong torque transfer while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If multiple clamping members are used to secure the cutting head, then reliability of attachment is improved, but the ease of operation decreases due to more clamping components

Engineering Contradiction:
Improveattachment reliabilityVSAvoidclamping operation simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The clamping mechanism is segmented into multiple identical frusto-conical clamping members distributed around the locating pin. This segmentation provides balanced, multi-point clamping that enhances attachment reliability and prevents uneven loading, while the modular nature of the segmented design allows for straightforward assembly and operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The frusto-conical geometry of the clamping members provides self-centering and self-aligning characteristics that simplify operation. The curved conical surfaces guide the clamping members into proper position during assembly and ensure uniform distribution of clamping force, making the operation intuitive and reliable without requiring complex adjustment procedures.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP3703891B1Cutting head and rotary cutting tool having same releasably clamped to a shank via a locating pin
Publication Date: 2024.07.10 ISCAR LTD
  • EP3703891B1 patent drawingFigure 1~2
  • EP3703891B1 patent drawingFigure 3~4
  • EP3703891B1 patent drawingFigure 5

AI summary

A rotary cutting tool (20) includes a cutting head (22) and a tool shank (24), each having an axial abutment surface (66, fig. 3; 102, fig. 6) and a plurality of drive surfaces (52, fig. 3; 88, fig. 6). One of the two (22, 24) includes a locating pin (38), while the other includes a pin receptacle (80) and at least one clamping through bore (84) that opens out to the pin receptacle (80). The locating pin (38) is received into the pin receptacle (80). The cutting head (22) and tool shank (24) are releasably clamped together by at least one clamping member (28) that passes through the at least one clamping through bore (84) and acts on the locating pin (38) so that the drive surfaces (52, 88) and the axial abutment surfaces (66, 102) on each part (22, 24) abut each other.