Extendable Ladder Guide Layout for Smooth Section Alignment

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Solution Overview

Problem

Existing extendable ladders for emergency and rescue vehicles lack precise and smooth relative adjustment between ladder sections, particularly the uppermost and the section below it, while maintaining sufficient clearance for the swivel arm, leading to potential jerking and inadequate guidance.

Innovation Solution

An extendable ladder set with a pivot arm and guide arrangement featuring first and second guide units, spaced to allow double guidance and support, ensuring continuous alignment and clearance, and optionally including a telescopic boom arm with a tensioning device for cable management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed-length ladder is used, then the structure is simple and stable, but it cannot adapt to different height requirements

Engineering Contradiction:
Improveadaptability to different height requirementsVSAvoidladder structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The ladder is divided into multiple telescopic sections (first telescopic section, second telescopic section, etc.) that can independently extend and contract. Each section contains ladder rungs and side rails that can be adjusted relative to one another, enabling the ladder to achieve different total lengths while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The ladder employs telescopic mechanisms with movable connections between sections, allowing the ladder to dynamically change its length. The side rails and rungs are designed with sliding or telescoping joints that enable smooth extension and retraction while maintaining stability during use.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a telescopic ladder with multiple sections is used, then adaptability to different heights is improved, but the risk of structural instability and injury increases

Engineering Contradiction:
Improveheight adjustment capabilityVSAvoidstructural stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The locking mechanism is designed so that the locked state (stable configuration) is the default or easier-to-achieve state, while extension requires deliberate user action. The quick-lock mechanisms automatically engage when sections are extended, ensuring stability is the default state during use.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The ladder incorporates audible or tactile feedback mechanisms (clicking sounds, distinct positioning sensations) that confirm when telescopic sections are properly extended and locked into place. This feedback system ensures users can verify the stable configuration before use.

Inventive Principle:
Principle #23Feedback

3Reliability

If a complex locking mechanism is used, then structural stability is improved, but the ease of operation deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidease of extension and retraction
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism is designed to automatically engage and lock when telescopic sections are extended to a desired position. The user simply needs to extend the section, and the lock self-activates through mechanical engagement, eliminating the need for separate manual locking actions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The locking function is extracted as a separate, simple mechanical feature that operates independently from the extension motion. The quick-lock mechanisms are positioned to engage automatically during the extension process, separating the locking action from complex manual operations.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4486972B1Extendable ladder set with a plurality of ladder parts
Publication Date: 2026.05.06 ROSENBAUER INTERNATIONAL AG
  • EP4486972B1 patent drawingFigure 1
  • EP4486972B1 patent drawingFigure 2~3
  • EP4486972B1 patent drawingFigure 4

AI summary

The invention relates to an extendable ladder set (8) and to an emergency or rescue vehicle (1) equipped therewith. The ladder set (8) comprises a plurality of ladder parts (19 to 13) and a guide arrangement (33) for at least the first uppermost ladder part (9). The uppermost ladder part (9) comprises a ladder element (17) and a pivoting arm (18), which are connected to one another in an articulated manner by means of a pivoting arrangement (19), wherein, starting from an articulation axis (27), side rails (28) of the ladder element (17) project by a length (42) beyond the articulation axis (27) in the direction of a ladder head (15). The guide arrangement (33) comprises mutually opposite first and second guide units (34, 35), which are spaced apart by a distance (38) in the longitudinal extent of the ladder. The distances (38) between the first and second guide units (34, 35) each correspond at most to a length (42) by which the side rails (28) of the ladder element (17) project beyond the articulation axis (27).