Reciprocating Saw Object Detection Through the Workpiece

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Solution Overview

Problem

Existing hand-held power tools lack comprehensive and reliable protection mechanisms to detect objects within or near the workpiece during operation, particularly in jigsaw and saber saw devices, which can lead to accidents involving objects like body parts or tools.

Innovation Solution

The integration of a locating unit with multiple antennas, including capacitive, inductive, and ultrasonic sensors, and optical sensors, which emit and receive signals to detect objects outside and within the workpiece, combined with a workpiece guide means and a computing unit to determine object position and trigger warnings or protective measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locating unit with multiple antennas and sensors is integrated into the hand-held power tool, then detection reliability and safety protection are improved, but device complexity increases

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

Solution Approach 1:

The patent combines multiple different types of sensors (capacitive, inductive, ultrasonic, and optical sensors) into a single integrated locating unit. This merging approach allows the system to detect objects through multiple physical principles simultaneously, significantly improving detection reliability and coverage while managing the complexity through unified integration rather than separate systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locating unit is designed with multi-functional capability by incorporating sensors that operate on different physical principles (capacitive, inductive, ultrasonic, optical). This universal design enables the single locating unit to detect various types of objects under different conditions, enhancing reliability without requiring multiple separate detection systems.

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

2Reliability

If the locating unit detects objects within the workpiece (through the workpiece support plane), then comprehensive protection is improved, but the workpiece support plane structure becomes more complex

Engineering Contradiction:
Improveprotection comprehensivenessVSAvoidworkpiece support plane structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locating chamber is integrated within or behind the workpiece guiding means, with the locating unit nested into the tool structure. The locating chamber penetrates the workpiece support plane, allowing sensors to detect through the support structure without requiring a completely separate external detection system. This nesting approach provides comprehensive protection while minimizing structural complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If the detection area extends beyond the workpiece support plane by more than 5 cm, then safety coverage is improved, but the antenna design becomes more complex

Engineering Contradiction:
Improvesafety coverageVSAvoidantenna design
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detection area is extended in the dimension perpendicular to the workpiece support plane by positioning the locating unit behind the workpiece guiding means and allowing the detection area to project forward beyond the support plane. This dimensional arrangement enables safety coverage extension without requiring complex antenna configurations, as the spatial positioning itself provides the extended detection range.

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

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

This configuration provides comprehensive and reliable protection by detecting objects within the workpiece's vicinity, preventing accidents through visual, acoustic, and tactile warnings or tool shutdowns, enhancing safety and operational efficiency.

Implementation Method 1

a locating unit having a capacitive antenna and designed to detect an operator's hand outside a workpiece

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

the locating unit includes antennas for different fields and/or signals... Preferably, the locating unit could include an inductive antenna for live conductors

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 3

the locating unit could include an ultrasonic sensor and/or an optical sensor, particularly for locating the sensor and the workpiece

Methodology Applied
Scientific EffectUltrasound: Ultrasound

Implementation Method 4

the locating unit could include an ultrasonic sensor and/or an optical sensor, particularly for locating the sensor and the workpiece

Methodology Applied
Scientific EffectLight: Light

Data Source

PatentEP2621681B1Mechanical hand tool device
Publication Date: 2022.04.27 ROBERT BOSCH GMBH
  • EP2621681B1 patent drawingFigure 1
  • EP2621681B1 patent drawingFigure 2~3
  • EP2621681B1 patent drawingFigure 4~5

AI summary

The invention relates to a mechanical hand tool device, in particular a fret and/or reciprocating saw device, comprising a locating unit (26a, 26b) which has at least one antenna (28a-f, 30a-f, 68d, 68f, 70d, 70f, 72f, 74f, 76f, 78f) and is provided in order to detect objects outside a workpiece (22a). According to the invention, it is proposed that the locating unit (26a, 26b) be provided so as to detect objects inside the workpiece (22a).