Work Machine Cab Door Gas Spring Biasing Mechanism

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Solution Overview

Problem

Conventional work machine cab doors can unintentionally open due to gravitational force, posing a problem during maintenance or cleaning, such as when windows are being cleaned.

Innovation Solution

A cab for a work machine equipped with a biasing member, like a gas spring, that biases the door in the closing direction, preventing it from opening against the operator's intention by using a combination of an actuator and a power transmission device to control the door's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the door is allowed to open freely under gravitational force, then the door can be easily opened for access, but the door may open unintentionally causing safety problems during cleaning or maintenance

Engineering Contradiction:
Improveease of door openingVSAvoiddoor position stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The biasing member applies a preliminary closing force to the door in advance, creating a pre-tensioned state that resists unintended opening. This preliminary anti-action counteracts gravitational force before unwanted movement occurs, ensuring the door remains reliably closed during cleaning or maintenance operations while still allowing intentional opening when needed

Inventive Principle:
Principle #9Preliminary anti-action

2Reliability

If a biasing member is added to prevent unintended door opening, then door position stability is improved, but the device complexity increases

Engineering Contradiction:
Improvedoor position stabilityVSAvoiddoor mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The biasing member is configured to automatically maintain door closure without requiring external control systems, sensors, or power sources. The mechanism self-regulates by utilizing the inherent mechanical properties of the biasing member to counteract gravitational force, achieving reliable door position stability while avoiding additional complexity from electronic controls or complex mechanical linkages

Inventive Principle:
Principle #25Self-service

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

The solution effectively prevents the door from being opened unintentionally, ensuring it remains closed during intended operations and automatically closes if slightly opened, thereby enhancing operator safety and control.

Implementation Method 1

The biasing member biases the door in the closing direction

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

A cab as disclosed herein includes a cab body, a door, and a biasing member. ... equipped with a biasing member, like a gas spring

Methodology Applied
Scientific EffectPneumatics: Gas Compressor

Data Source

PatentEP3719215B1Work machine cab and work machine
Publication Date: 2024.04.24 KOMATSU LTD
  • EP3719215B1 patent drawingFigure 1
  • EP3719215B1 patent drawingFigure 2
  • EP3719215B1 patent drawingFigure 3

AI summary

Provided are a cab for a work machine and a work machine capable of preventing a door from opening against an operator's intention. The cab includes a cab body, a door (61), and a gas spring (170). The cab body is formed with a doorway. The door (61) is rotatably supported on the cab body. The door (61) opens and closes the doorway. The gas spring (170) biases the door (61) in the closing direction.