Tool Shank Central Recess for Repeatable Cutting Head Retention
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Solution Overview
Problem
Existing rotary cutting tools with head receiving pockets and resiliently displaceable abutment portions face challenges in achieving high repeatability and longevity in metal cutting processes, particularly in drilling operations, due to the limitations of circumferentially open central recesses and abutment designs.
Innovation Solution
A tool shank with a circumferentially confined central recess and resiliently displaceable abutment portions, where the central recess does not intersect chip flutes, and the abutment portions are radially inward facing, providing a 'circumferentially confined' design that enhances resilience and tool longevity, allowing for a cutting head to be releasably mounted with high repeatability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circumferentially open central recess is used with resiliently displaceable abutment portions, then the cutting head can be retained in the head receiving pocket, but the tool life and repeatability are insufficient
Solution Approach 1:
The central recess is segmented into multiple discrete abutment portions (first, second, third, and fourth abutment portions) arranged circumferentially around the recess. This segmentation allows each abutment portion to independently engage with corresponding engagement surfaces on the cutting head, providing distributed support and improving both repeatability and tool life through localized load bearing.
Solution Approach 2:
Different regions of the central recess are given different properties through the alternating arrangement of abutment portions and intermediate portions. The abutment portions provide rigid engagement surfaces for cutting head retention, while the intermediate portions provide flexibility and resilience. This local differentiation of properties enables the structure to simultaneously achieve high repeatability through precise engagement and extended tool life through stress distribution.
2Reliability
If additional fastening members are used to secure the cutting head, then the retention reliability is improved, but the device complexity increases
Solution Approach 1:
The resiliently displaceable abutment portions are designed to automatically engage and retain the cutting head without requiring additional fastening members. The intermediate portions provide the necessary resilience to allow the abutment portions to displace and then spring back into engagement, creating a self-retaining mechanism that eliminates the need for separate fastening components while maintaining high retention reliability.
Solution Approach 2:
The functions of retention, support, and fastening are merged into the single integrated structure of the central recess with resiliently displaceable abutment portions. The abutment portions simultaneously provide cutting head retention through their engagement surfaces, structural support through their rigid configuration, and fastening function through their resilient displacement capability, eliminating the need for separate fastening members.
3Ease of manufacture
If the central recess intersects the chip flutes, then the manufacturing is simplified, but the tool longevity is reduced
Solution Approach 1:
The central recess is segmented such that it does not continuously intersect the chip flutes, but rather is interrupted by intermediate portions that alternate with abutment portions. This segmentation allows the recess to be manufactured with discrete features that can be precisely controlled, while the non-intersecting design prevents stress concentration at flute intersections, thereby extending tool longevity.
4Manufacturing precision
If the abutment portions are made rigid, then the manufacturing precision is improved, but the resilience and tool flexibility are reduced
Solution Approach 1:
The abutment portions are designed with local quality differentiation where the engagement surfaces (first and second abutment surfaces) are made rigid and precisely finished to ensure accurate cutting head retention, while the body of the abutment portions and the intermediate portions are designed with resilient properties to allow controlled displacement. This local differentiation enables high manufacturing precision at the engagement interfaces while maintaining overall system resilience.
Solution Approach 2:
The abutment portions are designed to be resiliently displaceable rather than completely rigid, allowing them to dynamically adjust during operation. The intermediate portions provide the necessary compliance to allow the abutment portions to displace under load and then return to their original position, creating a dynamic system that maintains precise engagement while absorbing operational stresses.
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
The solution provides improved resilience and extended tool life by ensuring the cutting head is securely retained without additional fastening members, enhancing the reliability and durability of the rotary cutting tool in metal cutting processes.
Implementation Method 1
a plurality of resiliently displaceable abutment portions circumferentially alternating with and spaced apart by a plurality of intermediate portions, each abutment portion having a radially inward facing abutment surface
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A tool shank (20) has a head receiving pocket (22) at a forward end (24), and a plurality of chip flutes (26) extending rearwardly therefrom along a longitudinal axis (Al). The head receiving pocket has a support surface (30) transverse to the longitudinal axis. A central recess (32) is formed in the support surface and extends rearwardly therefrom. The central recess has a plurality of resiliently displaceable abutment portions (38) circumferentially alternating with and spaced apart by a plurality of intermediate portions (40). Each abutment portion has a radially inward facing abutment surface (42), and each intermediate portion has an intermediate surface (44) intersecting two circumferentially adjacent abutment surfaces. A rotary cutting tool includes the shank and a cutting head releasably mounted thereto. The cutting head has a mounting portion provided with a base surface and an engagement member protruding therefrom. In an assembled position, the engagement member is resiliently retained in the central recess against the plurality of abutment surfaces.