Foldable Ladder Control for Aligned Working Machine Access

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Solution Overview

Problem

Current access systems for working machines with pivotable upper and lower carriages are non-ergonomic and pose safety concerns for ascending and descending, as they require significant mobility and do not ensure safe access to the upper carriage cabin.

Innovation Solution

A foldable ladder system with a control system that aligns the upper and lower carriages before allowing movement, ensuring safe access and descent by blocking or enabling the ladder's movement based on carriage alignment, and incorporating sensors for safety and ergonomic design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a fixed ladder system is used for access to the upper carriage, then the structure is simple and stable, but the system is non-ergonomic and requires significant mobility of the person to get on and off safely

Engineering Contradiction:
Improveergonomics of accessVSAvoidladder system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by implementing a foldable ladder that can change its configuration between extended and retracted positions. The ladder transitions from a static fixed structure to a dynamic movable structure, allowing it to adapt between providing ergonomic access when needed and not interfering with machine operations when retracted. This dynamic capability resolves the contradiction by enabling the system to optimize ergonomics during access while maintaining simplicity during normal operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The ladder system is segmented into multiple movable sections that can fold and extend independently. This segmentation allows the ladder to be divided into manageable parts that can be stored compactly when not in use and deployed when needed for ergonomic access. The segmented structure enables the ladder to provide ergonomic benefits without requiring a permanently complex fixed structure.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If a foldable ladder is provided to improve access ergonomics, then the ergonomics of ascent and descent is improved, but the ladder may disturb the movement or pivoting of the working machine when extended

Engineering Contradiction:
Improveergonomics of ascent and descentVSAvoidmachine movement capability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The foldable ladder is designed as a dynamic structure that can transition between extended and retracted positions. When extended, it provides ergonomic access to the upper carriage. When retracted, it becomes compact and does not interfere with the machine's movement or pivoting operations. This dynamic adaptability resolves the contradiction by allowing the ladder to optimize ergonomics only when needed while maintaining full machine versatility during operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The ladder sections are designed to nest within each other when retracted, similar to nested dolls. This nesting mechanism allows the ladder to occupy minimal space when not in use, preventing interference with machine movements while still providing full ergonomic access capability when deployed. The nested configuration ensures the ladder does not disturb machine operations during normal work cycles.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If the ladder is made movable to improve safety and ergonomics, then access safety is improved, but additional control systems and sensors are required which increase system complexity

Engineering Contradiction:
Improveaccess safetyVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system is designed to perform preliminary actions by automatically detecting when the ladder is in use and pre-positioning safety mechanisms accordingly. The system proactively monitors ladder position and machine state, enabling safety functions before actual access occurs. This preliminary action approach improves safety while keeping the control system relatively simple by automating safety preparations rather than requiring complex real-time intervention systems.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The ladder system incorporates self-monitoring capabilities where sensors automatically detect the ladder's position and state, and the control system autonomously determines when to enable or disable ladder movement based on detected conditions. This self-service approach improves safety by eliminating the need for complex manual control systems, as the system monitors and regulates itself based on predetermined safety criteria.

Inventive Principle:
Principle #25Self-service

4Volume of moving object

If the ladder is stored between the upper and lower carriage in horizontal position, then the storage space is optimized and the ladder does not stick out from the working machine, but the mechanism for achieving and maintaining this position becomes more complex

Engineering Contradiction:
Improveladder storage spaceVSAvoidladder positioning mechanism complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The ladder positioning mechanism utilizes dynamic motion to transition the ladder between vertical extended position and horizontal retracted position. By employing dynamic folding and rotating joints, the system achieves compact horizontal storage between the carriages without requiring complex fixed positioning structures. The dynamic mechanism allows the ladder to naturally assume the horizontal storage position through controlled movement, reducing the need for additional complex retention mechanisms.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4299379A1Stair system for a working machine, working machine
Publication Date: 2024.01.03 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP4299379A1 patent drawingFigure 1A~1B
  • EP4299379A1 patent drawingFigure 2A~2B
  • EP4299379A1 patent drawingFigure 2C~3A

AI summary

The invention relates to a stair system for a working machine having an upper carriage and a lower carriage pivotable against each other comprising a foldable ladder movable between an upper end position and a lower end position, wherein in the upper end position the ladder is arrangeable at the working machine in a way that moving and pivoting of the working machine is not disturbed and wherein in the lower end position the ladder is able to provide access to the upper carriage, preferably to a cabin, of the working machine; a control system comprising at least one alignment sensor indicating alignment of the upper and lower carriage and a controller which is able to block or enable a movement of the foldable ladder based on an output of the alignment sensor.