Power Tool Sensor Array Control for Workpiece Kickback Prevention

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Solution Overview

Problem

Power tools often experience undesirable relative motion between the workpiece and the workpiece support, leading to potential damage or kickback conditions, necessitating improved detection and response mechanisms to maintain a fixed orientation during operations like cutting, drilling, or grinding.

Innovation Solution

Incorporating a sensor array that detects physical contact between the workpiece and the support surface, generating a sensor output used by a controller to control the power tool's operation, ensuring a fixed orientation and preventing kickback or damage by adjusting the implement's motion based on detected contact and position changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sensor array is added to detect workpiece position and contact, then the ability to detect and respond to relative motion is improved, but the device complexity increases

Engineering Contradiction:
Improvedetection capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensor array is pre-positioned on the workpiece support to detect contact and position before problematic relative motion occurs. This allows the system to anticipate and prevent kickback conditions by detecting workpiece placement and movement in real-time, rather than reacting after damage occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sensor array provides continuous feedback about workpiece contact and position to the control system. This feedback loop enables real-time adjustments to maintain proper workpiece support and prevent relative motion that could lead to kickback or damage, directly improving reliability through closed-loop control.

Inventive Principle:
Principle #23Feedback

2Stability of the object's composition

If the workpiece support maintains a fixed orientation relative to the workpiece, then the stability and prevention of kickback is improved, but the ease of operation decreases due to restricted workpiece positioning flexibility

Engineering Contradiction:
Improveworkpiece support stabilityVSAvoidworkpiece positioning flexibility
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The system dynamically adjusts between maintaining fixed orientation for stability during cutting operations and allowing positioning flexibility during setup. The sensor array and control system enable the workpiece support to adapt its degree of fixation based on operational phase, combining stability during operation with ease of positioning during setup.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sensor array automatically detects when the workpiece is properly positioned and when it begins to move, eliminating the need for manual monitoring. The system self-regulates to maintain stable orientation when needed while allowing flexible positioning during setup, improving both stability and ease of operation through automated control.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4311616A1Power tools with sensor arrays and methods of operating power tools
Publication Date: 2024.01.31 FESTOOL GMBH
  • EP4311616A1 patent drawingFigure 1
  • EP4311616A1 patent drawingFigure 2
  • EP4311616A1 patent drawingFigure 3

AI summary

Power tools with sensor arrays and methods of operating power tools are disclosed herein. In addition to the sensor arrays (100), the power tools (10) include an implement holder (20), a motor (40), a workpiece support (50), and a controller (120). The implement holder is configured to hold an implement (30). The motor is configured to receive an electric current and to actuate the implement holder to move the implement. The workpiece support includes a support surface (52) configured to support the workpiece (90) and is configured to maintain an at least substantially fixed orientation relative to the workpiece while the implement performs an operation on the workpiece. The sensor array (100) is configured to detect physical contact between the workpiece support and the workpiece and to generate a sensor output (104). The controller is programmed to receive the sensor output and to control the operation of the power tool based, at least in part, on the sensor output.