Industrial Vehicle Step Assembly With Door-Linked Retractable Step

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Solution Overview

Problem

Industrial vehicle boarding steps, especially on off-road vehicles like mining trucks, are prone to damage from obstacles and rust due to their location within the vehicle's approach angle, leading to inconvenience and safety hazards when dismantled for protection.

Innovation Solution

A step assembly with a mobile step member that deploys closer to the ground when needed and stows out of the approach angle when not in use, actuated by an actuation cable and elastic member, automatically adjusting with the entry door's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a second boarding step is installed closer to the ground within the approach angle area, then ease of access to the cabin is improved, but the step becomes vulnerable to damage from obstacles and rust during off-road driving

Engineering Contradiction:
Improveease of accessVSAvoiddamage resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The step assembly transitions from a static fixed structure to a dynamic movable structure that can change position between deployed and stowed states. The mobile step member is actuated by a cable linkage connected to the door mechanism, allowing automatic deployment when the door opens and retraction when the door closes, resolving the contradiction between accessibility and damage resistance

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The step assembly is divided into separate functional components: a fixed step portion attached to the vehicle body, and a mobile step member that can move independently. This segmentation allows the mobile portion to be positioned for accessibility when needed while being protected during off-road operation by retracting it into a safe position

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the mobile step member is deployed closer to the ground, then ease of access is improved, but the step enters the approach angle zone where it can be damaged by obstacles

Engineering Contradiction:
Improveease of accessVSAvoidobstacle damage risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The mobile step member dynamically adjusts its position based on operational needs. When the door is open and access is required, the step deploys to a lower position for ease of access. When the door is closed and the vehicle is in off-road mode, the step retracts to a higher position outside the approach angle zone, eliminating obstacle damage risk

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The step assembly is automatically actuated in advance of potential damage scenarios. The cable linkage connected to the door mechanism ensures the step is retracted into the safe zone before off-road driving begins, and deployed before access is needed, preventing both damage and ensuring accessibility

Inventive Principle:
Principle #10Preliminary action

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

Provides easy access to the vehicle cabin while protecting the step from damage during off-road driving, maintaining functionality without manual stowage actions.

Implementation Method 1

the step assembly comprises an elastic member configured for moving the mobile step member from the deployed position to the stowed position in response to a closing of the entry door

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the actuation member is an actuation cable

Methodology Applied
Scientific EffectTension: Tension

Data Source

PatentEP4212392B1Step assembly for an industrial vehicle
Publication Date: 2025.07.23 VOLVO TRUCK CORP
  • EP4212392B1 patent drawingFigure 1
  • EP4212392B1 patent drawingFigure 2(A)~2(B)
  • EP4212392B1 patent drawingFigure 3

AI summary

The invention relates to a step assembly (1) for helping a user entering a cabin (50) of an industrial vehicle (100), the step assembly (1) comprising: - a check link (2) configured to be linked to an entry door (40) of the cabin (50), - an actuation cable (3), - a mobile step member (4) configured to be movable between a stowed position (S) and a deployed position (E), the actuation member (3) linking the mobile step member (4) and the check link (2), in which the mobile step member (4) is configured to be moved from the stowed position (S) to the deployed position (E) by the actuation member (3) in response to an opening of the entry door (40).