Weldon Toolholder Jaw Recess for Stuck Tool Removal

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Solution Overview

Problem

Under extreme working conditions, especially in core hole drilling machines, axial material accumulation occurs at the transition area of the flat contact surface to the cylindrical part of the tool shank, leading to the tool becoming stuck in the working spindle.

Innovation Solution

The clamping surface of the clamping jaw is designed to contact the flat surface of the tool shank only at points protected by the side of the flat surface, with an axially running recess in the clamping surface shifting the contact area inward, away from the transition area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the clamping surface contacts the flat surface at the transition area, then the tool is securely locked in the working spindle, but material accumulation occurs that prevents tool removal

Engineering Contradiction:

Improvetool locking securityVSAvoidtool removal ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The clamping surface is segmented into two distinct zones: a first clamping zone that contacts the flat surface for secure locking, and a second clearance zone near the transition area that prevents material accumulation. This segmentation allows the tool to be securely locked while enabling easy removal by preventing material buildup in the critical transition area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the clamping surface are given different functional qualities: the first region has clamping functionality for secure locking, while the second region has clearance functionality to prevent material accumulation. This local differentiation resolves the contradiction by optimizing each region for its specific purpose.

Inventive Principle:

Principle #3Local quality

2Force

If the contact area is extended to the transition area, then clamping force is increased, but material accumulation exceeds the inner radius and blocks tool extraction

Engineering Contradiction:

Improveclamping forceVSAvoidmaterial accumulation blocking

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The clamping surface is divided into a first clamping zone for force application and a second clearance zone to prevent material accumulation. This segmentation allows maximum clamping force to be applied where needed while maintaining a clearance zone that prevents material from blocking tool extraction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The design converts the potential harm of material accumulation into a benefit by strategically positioning the clearance zone to redirect material flow away from the transition area, where material accumulation would cause blocking. The clearance zone acts as a sacrificial area that protects the critical transition region.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS20250135555A1Toolholder and toolholder system comprising the same

Publication Date: 2025.05.01 C & E FEIN GMBH & CO KG

AI summary

A toolholder for a tool having a flat surface that can be rotated about an axis of rotation, in particular, a Weldon toolholder for a milling tool or a core drill. A clamping jaw has a contact surface spaced from the flat surface side of the flat surface and touches the flat surface when the clamping jaw is pressed against the flat surface in a second arrangement of the clamping jaw or in the assembly position of the tool. A stationary machine tool comprising this toolholder and a tool and a method for manufacturing thereof are also provided.