Retractable Step With Pivoting Lower Segment For HGV Access

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Solution Overview

Problem

Existing retractable steps for heavy goods vehicles are limited in size due to their deployment mechanism, leading to increased risk of falls and discomfort during emergency situations, as they either protrude when retracted or are too small for effective use.

Innovation Solution

A telescopic step system with an upper and lower step, utilizing a hydraulic or pneumatic cylinder for deployment and retraction, featuring a pivoting mechanism that allows the steps to be compactly stored behind the wheel while providing an emergency step for safe access, even when retracted, and larger dimensions when deployed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the step is designed to be retractable and fold up at the rear of the wheel, then the step does not protrude beyond the vehicle gauge when retracted, but the step dimensions are limited and the step may be blocked in retracted position

Engineering Contradiction:
Improverisk of fallsVSAvoidstep dimensions
Core Design Contradiction:
Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The step is divided into two separate steps (first step and second step) that can be independently controlled. This allows one step to remain deployed for use while the other is retracted, providing continuous access options and preventing complete blockage of access even when one step is in retracted position.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The step system employs dynamic control through independent actuators for each step, allowing flexible configuration between retracted and deployed states. This dynamic capability enables the system to adapt to different situations, maintaining safety while avoiding the limitation of fixed-size steps.

Inventive Principle:
Principle #15Dynamics

2Volume of moving object

If the step deployment mechanism uses a double rod cylinder, then the mechanism is compact and the cylinder serves as both actuator and carrier, but the device complexity increases

Engineering Contradiction:
Improvemechanism compactnessVSAvoiddisplacement mechanism complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The double rod cylinder combines two functions into a single component: it acts as both the actuator that provides mechanical force and the carrier that supports the step structure. This merging eliminates the need for separate mounting structures and reduces overall mechanism volume while managing the inherent complexity through functional integration.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If the lower step is pivotally mounted with respect to the upper step, then the steps can be moved in translation and pivoted to different orientations, but the device complexity increases

Engineering Contradiction:
Improvestep orientation flexibilityVSAvoidpivoting mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pivotal mounting creates a dynamic system where the lower step can rotate relative to the upper step, enabling orientation changes from facing the vehicle to facing outward. This dynamic capability provides versatility in step positioning while the simplicity of the pivot joint keeps the added complexity minimal compared to more sophisticated positioning mechanisms.

Inventive Principle:
Principle #15Dynamics

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 telescopic step system ensures safe and comfortable boarding and disembarking without protruding when retracted, while allowing for larger step dimensions than previous designs, reducing the risk of falls and enhancing emergency access.

Implementation Method 1

the displacement means comprises a hydraulic or pneumatic cylinder

Methodology Applied
Scientific EffectHydraulic or pneumatic actuation: Hydraulic Press

Implementation Method 2

the moving means further comprises a pivoting means for pivoting the lower step

Methodology Applied
Scientific EffectPivoting mechanism: Hinge

Data Source

PatentEP3042804B1Retractable step
Publication Date: 2017.08.09 GRP MECALAC
  • EP3042804B1 patent drawingFigure 1~2
  • EP3042804B1 patent drawingFigure 3~4
  • EP3042804B1 patent drawingFigure 5~6

AI summary

The step (1) is designed to be positioned at the wheel (3) of a vehicle (2). It comprises an upper step (4), a lower step (5), and a means (6) for extending and retracting it. In the retracted position, the upper (4) and lower (5) steps are folded behind the wheel (3) so as not to protrude beyond the vehicle's (2) dimensions. In the extended position, the upper (4) and lower (5) steps are positioned close to the outer edge of the wheel (3), projecting outwards to allow the driver to enter and exit the cab. The lower step (5) pivots 180 degrees during its extension and includes a spare step (17) at its rear so that it can be used when the step (1) is retracted.