Tool Holder With Grooved Elongated Hole for Secure Locking

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Solution Overview

Problem

Existing tool holders for percussion machine tools, such as chipping hammers, lack a secure mechanism to hold tools with prismatic or cylindrical shank ends, leading to potential tool disengagement during operation.

Innovation Solution

A tool holder design featuring a receiving sleeve with a prismatic cavity and elongated holes, where the holes have a groove on the inner surface parallel to the working axis, allowing for secure engagement of locking balls that prevent tool dislodgment, and optionally featuring slots and longitudinal grooves for additional stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple receiving sleeve is used to hold tools, then the device complexity is reduced, but the tool retention security deteriorates

Engineering Contradiction:
Improvestructure complexityVSAvoidtool retention security
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The receiving sleeve is segmented into functional zones: an elongated hole for locking body movement, a groove for lateral positioning, and a cavity for tool reception. This segmentation allows each zone to perform its specific function independently, achieving secure tool retention through coordinated interaction of simple geometric features without adding complex mechanisms.

Inventive Principle:
Principle #1Segmentation

2Reliability

If locking balls are added to secure tools, then the tool retention security is improved, but the device complexity increases

Engineering Contradiction:
Improvetool retention securityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking balls utilize the geometry of the elongated hole and groove to automatically position and secure themselves during tool insertion. The balls move freely along the elongated hole, are laterally positioned by the groove, and engage with the tool's locking groove without requiring external actuation or complex control mechanisms, achieving self-securing functionality.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The elongated hole serves multiple functions: it guides the locking balls during insertion, allows their lateral movement for engagement, and provides a pathway for their axial displacement during tool changes. This multi-functionality reduces the need for separate guiding structures, maintaining simplicity while ensuring reliable locking.

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

3Manufacturing precision

If the groove extends the slot along the working axis, then the locking body positioning precision is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvelocking body positioning precisionVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The groove is formed as a continuous curved feature that extends the slot along the working axis, providing smooth lateral guidance for the locking balls. This curved geometry achieves precise positioning through its continuous surface rather than through multiple discrete features, simplifying manufacturing compared to creating separate positioning elements.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP2492054B1Tool holder
Publication Date: 2016.05.18 HILTI AG
  • EP2492054B1 patent drawingFigure 1~2
  • EP2492054B1 patent drawingFigure 3~6
  • EP2492054B1 patent drawingFigure 7~9

AI summary

The tool holder has a receiving sleeve (20) that includes a cylindrical or prismatic cavity (21) for receiving a machine tool along a working axis (4). An elongated hole (30) is formed in the receiving sleeve for receiving a locking element in parallel to the working axis. The grooves (71,72) are provided in an inner surface (35) of the receiving sleeve such that the holes in the inner surface of sleeve are prolonged along the working axis.