Power Tool Height Sensing for Accurate Cutting Depth

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Solution Overview

Problem

Existing mobile machine tools face challenges in accurately adjusting the optimal penetration depth of the working tool into a workpiece, leading to suboptimal cutting quality and increased machining forces.

Innovation Solution

Incorporating a height-measuring device with optical sensors and distance sensors to detect the workpiece edges, allowing for precise determination of the workpiece height and automatic adjustment of the tool holder, enabling optimal penetration depth setting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual measurement methods (meter rule) are used to determine workpiece height, then the operator can obtain height information, but the operation becomes cumbersome and time-consuming

Engineering Contradiction:
Improveease of height measurementVSAvoidtime for height measurement
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical measurement (meter rule) with an optical measurement system that automatically detects workpiece height. The optical sensor and evaluation device eliminate the need for manual intervention, directly resolving the contradiction by substituting mechanical measurement with automated optical detection.

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

Solution Approach 2:

The height measuring device enables the system to measure workpiece height automatically without operator intervention. The device self-adjusts and provides height information autonomously, allowing the machine tool to serve itself in the measurement process, thus improving ease of operation and reducing time loss.

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If the penetration depth is not optimally adjusted, then the machine tool can operate without complex adjustment mechanisms, but the cutting quality deteriorates and machining forces increase

Engineering Contradiction:
Improvecutting qualityVSAvoidcomplexity of depth adjustment system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the optical height measuring device continuously monitors workpiece height and automatically adjusts the penetration depth of the working tool. This closed-loop feedback system ensures optimal cutting quality while managing device complexity through automated control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary measurement of the workpiece height before machining begins. By determining the optimal penetration depth in advance based on measured workpiece dimensions, the system prepares the optimal cutting parameters beforehand, ensuring high manufacturing precision from the start of operation.

Inventive Principle:
Principle #10Preliminary action

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

Improves cutting quality, reduces machining forces, and simplifies the operation by providing accurate and automatic adjustment of the tool penetration depth, enhancing overall machining efficiency.

Implementation Method 1

the height measuring device has, for example, contrast filters, median filters or other similar filters in order to determine the course of an edge

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3687726B1Mobile power tool
Publication Date: 2021.08.25 FESTOOL GMBH
  • EP3687726B1 patent drawingFigure 1
  • EP3687726B1 patent drawingFigure 2~5
  • EP3687726B1 patent drawingFigure 6~7

AI summary

The invention relates to a mobile power tool (10), more particularly a hand power tool (10) or semi-stationary power tool (10), for machining a workpiece (W), the power tool (10) having an in particular plate-type guide element (30) with a guide surface (32) for guiding the power tool (10) on the workpiece (W), or for guiding the workpiece (W) on the power tool (10). The power tool (10) has: a drive unit (11) comprising a drive motor (13) for driving a tool holder (14) that is located on the drive unit (11), wherein the drive unit (11) is moveably mounted on the guide element (30) by means of a bearing arrangement (35) for adjusting at least two actuating positions (S0, S1, S2) of the tool receptacle (14) relative to the guide surface (32) in which a working tool (15) arranged on the tool holder (14), in particular a separating tool, penetrates into the workpiece (W) at different penetration depths, in particular cuts into the workpiece (W). According to the invention, said power tool (10) comprises a height measuring device (95) for recognising a height (H) of the workpiece (W), wherein the height corresponds to a distance between a workpiece upper side (WO) provided for penetrating the working tool (15) and a workpiece (W) lower side (WU) which is opposite the workpiece upper side (WO).