Mobile Machine Tool Sensor Layout for Workpiece Contact Detection

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Solution Overview

Problem

Existing machine tools lack optimal monitoring of the workpiece contact area, particularly when the working tool partially covers the detection areas of tool sensors, leading to suboptimal visibility and detection of the workpiece contact zones.

Innovation Solution

The machine tool employs at least two tool sensors positioned on opposite sides of the working tool, with a section of the working tool engaging in the workpiece, allowing each sensor to detect partial contact areas optimally. Additional features include adjustable tool holder settings, illumination devices for improved visibility, and a switching mechanism to prioritize sensor signals based on operational conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single tool sensor is used to detect the workpiece contact area, then the device complexity is low, but the measurement precision and coverage of the workpiece contact area are insufficient when the working tool partially covers the detection area

Engineering Contradiction:
Improvedetection accuracy of workpiece contact areaVSAvoidnumber of tool sensors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection task is segmented by dividing the workpiece contact area into multiple sub-areas, with each tool sensor responsible for detecting a specific sub-area. This segmentation allows comprehensive coverage of the entire contact area including regions partially obscured by the working tool, thereby improving measurement precision without requiring a single complex sensor

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple tool sensors are merged into a coordinated detection system where each sensor detects a specific workpiece contact sub-area. The signals from all sensors are combined to provide complete monitoring of the workpiece contact area, resolving the contradiction between using multiple sensors and maintaining simple device complexity

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If tool sensors are positioned to detect the entire workpiece contact area, then the measurement precision is high, but the working tool cannot engage properly in the workpiece

Engineering Contradiction:
Improvedetection coverage of workpiece contact areaVSAvoidworking tool engagement in workpiece
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The detection area is segmented and assigned to different sensors positioned on opposite sides of the working tool. This allows the working tool to engage freely in the workpiece while each sensor monitors its designated sub-area, achieving both complete detection coverage and proper tool engagement

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The detection system transitions from a single-dimensional detection approach to a multi-dimensional arrangement with sensors positioned on opposite sides of the working tool. This spatial distribution allows the working tool to engage in the workpiece while sensors on both sides detect their respective contact sub-areas simultaneously

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If the working tool is positioned to engage in the workpiece, then the machining operation is effective, but the detection area of one sensor is covered by the working tool

Engineering Contradiction:
Improvemachining effectivenessVSAvoidundetected workpiece contact sub-area
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The workpiece contact area is segmented into multiple sub-areas, with each sub-area assigned to a specific tool sensor. This segmentation ensures that when the working tool engages in the workpiece for effective machining, each sensor can still detect its designated sub-area without interference, preventing information loss

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple tool sensors create redundant detection capabilities for different portions of the workpiece contact area. This copying approach ensures that even when one sensor's detection area is partially covered by the working tool during machining, the complete contact area information is still captured by the other sensors

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3687741B1Mobile machine tool
Publication Date: 2022.08.24 FESTOOL GMBH
  • EP3687741B1 patent drawingFigure 1
  • EP3687741B1 patent drawingFigure 2~5
  • EP3687741B1 patent drawingFigure 6~7

AI summary

The invention relates to a mobile machine tool, namely a hand-held machine tool (10) or a semi-stationary machine tool, for machining a workpiece (W), wherein the machine tool (10) comprises a particularly plate-like guide element (30) having a guide surface (32) for guiding the machine tool (10) on the workpiece (W) or guiding the workpiece on the machine tool (10), wherein the machine tool (10) has a drive unit (11) with a drive motor (13) for driving a tool receiving portion (14) that is arranged on the drive unit (11), wherein the machine tool (10) comprises a tool sensor arrangement (61, 62) for detecting a workpiece contact region, in which a working tool (15), in particular a separating tool, which is arranged on the tool receiving portion (14), is in contact with the workpiece (W) and in particular cuts into the workpiece (W). It is provided that the tool sensor arrangement (61, 62) comprises at least two tool sensors (61, 62), the detection regions (EB1, EB2) of which being assigned to different workpiece contact partial regions (WK1, WK2) of the workpiece contact region.