Cab Door Hinge Mechanism Vertical Lift Obstacle Clearance

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Solution Overview

Problem

Existing work machine cab door hinge mechanisms suffer from limited interior space, non-variable opening characteristics, and increased effort in opening and closing due to inclined axes of rotation, leading to structural adjustments and potential damage from lateral forces and corrosion.

Innovation Solution

A hinge arrangement with a bolt and receptacle system allowing vertical movement of the cab door, enabling variable lift with rotation angle and minimizing shearing forces on seals, thus allowing comfortable access and obstacle clearance without structural changes to the machine.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a hinge mechanism with inclined axis of rotation is used, then the door can clear obstacles such as fenders, but the door causes negative influence on cabin shape and increases structural complexity

Engineering Contradiction:
Improvedoor clearance heightVSAvoidhinge mechanism complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent introduces a vertical lifting dimension to the door movement by using a hinge mechanism with a horizontal axis of rotation, allowing the door to move not only horizontally but also vertically. This dimensional change enables the door to clear obstacles like fenders while maintaining a simple hinge structure without inclined axes.

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

Solution Approach 2:

The door movement is segmented into two independent components: horizontal rotation around a horizontal hinge axis and vertical lifting motion. This segmentation allows each component to be optimized separately - the hinge provides stable rotation while the lifting mechanism handles obstacle clearance, reducing overall system complexity.

Inventive Principle:
Principle #1Segmentation

2Length of moving object

If a hinge mechanism with inclined axis is used to achieve obstacle clearance, then the door can move vertically, but the seal is subjected to shearing forces causing increased wear

Engineering Contradiction:
Improvedoor vertical movementVSAvoidseal life
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent changes the hinge axis orientation to be horizontal rather than inclined, separating the vertical lifting function from the rotational function. This allows the door to achieve vertical movement for obstacle clearance while the seal remains perpendicular to the movement direction, eliminating shearing forces and extending seal life.

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

3Device complexity

If the door is designed to move horizontally only, then the hinge structure is simple, but the door cannot clear obstacles and interior space is reduced

Engineering Contradiction:
Improvehinge structure simplicityVSAvoiddoor clearance capability
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

The patent adds a vertical dimension to the door movement by introducing a lifting mechanism that works in conjunction with the simple horizontal hinge. This allows the door to achieve both horizontal rotation and vertical lifting, clearing obstacles while maintaining hinge structure simplicity.

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

4Length of moving object

If the door rotation axis is inclined to clear obstacles, then the door can move over fenders, but the opening characteristics become non-variable and interior space is reduced

Engineering Contradiction:
Improvedoor obstacle clearanceVSAvoidopening characteristics variability
Core Design Contradiction:
Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent uses a horizontal hinge axis combined with vertical lifting to achieve obstacle clearance, decoupling the rotation and lifting functions. This provides variable opening characteristics where the door can be positioned at different angles and heights, improving adaptability while maintaining interior space.

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

Data Source

PatentEP3012394B1Working machine with cabin
Publication Date: 2020.01.22 LIEBHERR WERK BISCHOFSHOFEN GMBH
  • EP3012394B1 patent drawingFigure 1
  • EP3012394B1 patent drawingFigure 2
  • EP3012394B1 patent drawingFigure 3

AI summary

Working machine, in particular wheel loader, with a cab having a cab door pivotably mounted on the cab frame by means of a hinge arrangement, wherein the hinge arrangement comprises a frame part mounted on the cab frame and a door part rotatable relative to the frame part and mounted on the cab door, wherein a bolt is provided in the frame part or in the door part and a receptacle for the bolt is provided in the other of the parts (door part or frame part), wherein the receptacle is designed at least section by section such that a movement of the door part towards the frame part is associated with a vertical movement of the door part relative to the frame part and wherein the receptacle has different pitch heights and/or wherein the door part or the frame part is designed in multiple parts and comprises a first part formed with the bolt or with the receptacle and a second part rotatable relative to the first part.