Construction Machine Working Arm Angle Detection

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Solution Overview

Problem

Existing working arm devices for construction machines face challenges in unambiguously calculating the angle of rotation of a work tool with respect to the arm, especially during excavation when the angle detection means is prone to damage from contact with earth and sand.

Innovation Solution

A working arm device configuration that includes a link mechanism with a first and second link, where angle detection means is positioned between the inner surface of the first link and the outer surface of the arm's side wall, using a magnet and magnetic detector setup to accurately calculate the angle of rotation while protecting the detection means from damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the angle detector is positioned away from the work tool at the base end of the work tool cylinder, then the angle detector is prevented from being damaged through contact with earth and sand during excavation, but it becomes difficult to unambiguously calculate the angle of rotation of the work tool with respect to the arm when the work tool cylinder rotates in opposite directions

Engineering Contradiction:

Improveprotection of angle detectorVSAvoidangle of rotation calculation accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The angle detection function is extracted from the work tool cylinder base end and relocated to the first link. Specifically, angle detection means is disposed between the inner surface of the first link and the outer surface of the side wall of the arm, allowing accurate angle measurement while protecting the detector from damage during excavation operations

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of detecting the angle at the work tool cylinder base end (conventional approach), the patent inverts the detection location to the first link. This inversion allows the detection system to measure the angle of the first link with respect to the arm, which can be used to calculate the work tool angle unambiguously even when the cylinder rotates in opposite directions

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If the angle detection means is positioned close to the work tool for accurate angle detection, then the measurement precision is improved, but the angle detection means is prone to damage from contact with earth and sand during excavation

Engineering Contradiction:

Improveangle of rotation detection accuracyVSAvoiddamage from earth and sand contact

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The angle detection function is extracted from the work tool area and relocated to the first link, which is positioned away from the direct contact zone with earth and sand during excavation. This extraction maintains measurement precision while eliminating exposure to harmful factors

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The first link serves as an intermediary element between the arm and the work tool cylinder. By placing the angle detection means on the first link, the system measures the angle through this intermediary component that is not directly exposed to earth and sand contact, thus protecting the detection means while maintaining accurate angle measurement capability

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables unambiguous calculation of the work tool's angle of rotation relative to the arm and prevents damage to the angle detection system during excavation by positioning the detection means within the link mechanism, ensuring accurate and durable operation.

Implementation Method 1

angle detection means for detecting an angle of rotation of the first link with respect to the arm is disposed between an inner surface of the first link and an outer surface of the side wall of the arm

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentUS10563380B2Working arm or a construction machine having angle detection

Publication Date: 2020.02.18 CATERPILLAR SARL

AI summary

A front linkage for a construction machine which can uniquely calculate the rotation angle of the work tool relative to the arm and which can prevent the angle detection device from being damaged by contact with the soil during digging. The front linkage has an arm, a first link pivotally connected at one end to the front end side of the arm, and at the other end to one end of a second link, and a work tool which is pivotally connected to the other end of the second link and which is pivotally connected to the arm in a further front end side than the one end portion of the first link. The first link is positioned outward along the outer width of the side wall of the arm. An angle detecting device for detecting the rotation angle of the first link relative to the arm may comprise a magnet disposed on an inner surface of the first link and a magnetic detector disposed on the side wall outer surface of the arm.