Ladder Rung Anchoring via Plug-Induced Widening
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Solution Overview
Problem
Existing ladder designs lack sufficient stability, particularly in the anchoring of rungs to rails, which affects their ability to absorb pull-out and shearing forces, especially on uneven surfaces.
Innovation Solution
The ladder features bars and rungs made of hollow profiles with internal ribs and a plug that widens the rung upon insertion, providing secure anchoring at two axially spaced areas, enhancing stability and load-bearing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single compression method is used to anchor the rung in the stile, then the manufacturing process is simple, but the stability and pull-out resistance are insufficient
Solution Approach 1:
The single anchoring point is segmented into two separate anchoring zones along the rung axis. The first rib creates a first anchoring zone, and the second rib creates a second anchoring zone. This segmentation allows the rung to be anchored at multiple locations, significantly improving stability and resistance to pull-out forces while maintaining a relatively simple overall structure.
Solution Approach 2:
The plug acts as an intermediary tool that enables the widening of the rung end area. By inserting the plug and applying compression force, the rung material is forced to widen between the ribs, creating the anchoring effect. This intermediary mechanism allows for controlled deformation and anchoring without requiring complex direct fastening systems.
2Strength
If the rung wall thickness varies in the opening area, then the insertion process is easier, but the load-bearing capacity and overall stability decrease
Solution Approach 1:
The ribs are positioned and dimensioned to create localized widening zones specifically where needed for anchoring, while preserving the uniform wall thickness in the opening area. This local quality approach ensures that the critical opening region maintains optimal structural properties for load-bearing, while still achieving effective anchoring through the controlled widening between ribs.
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 improved anchoring method significantly increases the ladder's stability, allowing it to absorb higher pull-out and shearing forces, and maintains a consistent wall thickness for enhanced load-bearing capacity and reduced wear.
Implementation Method 1
the end of the piece of pipe with the plug is pressed through a jacket bore in a thicker pipe section against a support inside the thicker pipe section in such a way that the edge of the thinner pipe section protruding within the bore is spread apart and compressed
Implementation Method 2
The end of the piece of pipe is upset, viewed in the direction of insertion, in any case in front of the two webs mentioned
Data Source
Figure 1
Figure 2~3
AI summary
The conductor is composed of spherical shaped rung (1) and hollow sectional bar (6). Several ribs (3a,3b) are provided inside the rung, and specific end of hollow sectional bar is inserted inside the rung towards radial direction, via opening provided at specific end of rung. A plug (9) provided at insertion end of sectional bar is made to contact with the rung. The plug is designed such that the rung is expanded during insertion of sectional bar into the rung towards upstream and downstream of respective rib. An independent claim is included for a method for anchoring rung with hollow sectional bar.