Servo-Controlled Tool Holder Alignment in Hand-Held Power Tools

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Solution Overview

Problem

Existing hand-held machine tools face challenges in maintaining precise angular and longitudinal positioning of working tools relative to the workpiece, especially when the guide element is adjusted, leading to potential feed movements and alignment issues during machining.

Innovation Solution

The control device, in conjunction with the servomotor and bearing arrangements, ensures the tool holder maintains its angular and longitudinal position by adjusting the tool holder's pivot position and movement direction component parallel to the guide surface, allowing for translational adjustments while maintaining alignment with the workpiece, even when the guide element is adjusted by the operator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the guide element is adjusted by the operator, then the adaptability of the machine tool is improved, but the positioning precision of the working tool deteriorates due to potential feed movements and alignment issues

Engineering Contradiction:
Improveadjustability of guide elementVSAvoidpositioning precision of working tool
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The control device continuously monitors the position of the tool holder relative to the guide element and automatically adjusts it to maintain the correct angular and longitudinal position, compensating for any deviations caused by guide element adjustments

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The servomotor arrangement automatically compensates for positioning errors without requiring manual intervention, maintaining precise tool positioning independently of operator actions on the guide element

Inventive Principle:
Principle #25Self-service

2Ease of operation

If the tool holder is made movable relative to the guide element, then the ease of operation is improved, but the stability of the tool position deteriorates

Engineering Contradiction:
Improveadjustability of tool holderVSAvoidstability of tool position
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The tool holder is designed with movable degrees of freedom allowing dynamic adjustment, while the control system provides active stabilization to maintain precise positioning during operation

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Manual mechanical adjustment is replaced with an automated servomotor arrangement controlled by a control device, enabling precise positioning without compromising stability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3703918B1Hand-held power tool having a bearing arrangement
Publication Date: 2021.10.20 FESTOOL GMBH
  • EP3703918B1 patent drawingFigure 1~3
  • EP3703918B1 patent drawingFigure 4~5
  • EP3703918B1 patent drawingFigure 6~8

AI summary

The invention relates to a hand-held power tool (20) for machining a workpiece (W), comprising a drive motor (22), a tool holder (24) which can be driven by the drive motor (22) and which is for a working tool (25) for machining the workpiece (W), and a guide element (30) having a guide surface (31) for guiding the hand-held power tool (20) on the workpiece (W) in a working direction (AR), wherein the tool holder (24) is mounted via a bearing arrangement (40) such that it moves relative to the guide element (30) and said tool holder can be driven by a servo motor arrangement (50), wherein the hand-held power tool (20) can be swivelled via the bearing arrangement (40) about at least one adjusting swivel axis (S) passing through the guide surface (31) at an angle, in particular at a right angle, for the relative adjustment of the tool holder (24) relative to the guide element (30), wherein the hand-held power tool (20) has a control device (60) for controlling the servo motor arrangement (50). The control device (60) is configured for controlling the servo motor arrangement (50) in such a way that the servo motor arrangement (50) adjusts the tool holder (24) relative to the guide element (30), while maintaining a swivel position relative to the adjusting swivel axis (S) with a movement direction component (K1, K2) in parallel to the guide surface (31) of the guide element (30).