Extension Ladder With Offset Rungs and Side-Mounted Lock

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Solution Overview

Problem

Extension ladders are often heavy and difficult to maneuver due to the need for rigidity when extended, and traditional rung lock mechanisms are bulky and reduce the usable space on the rungs.

Innovation Solution

The ladder design includes a base section and a fly section with offset rails and rungs, a rung lock device with a pivotal arm that engages rungs below the surface, and bearing components to maintain slidable coupling, reducing depth and weight while allowing for adjustable extension and improved user safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional rigid ladder structure is used to ensure stability when extended, then the ladder can withstand bending and twisting forces, but the ladder becomes very heavy and difficult to maneuver

Engineering Contradiction:

Improveladder rigidityVSAvoidladder weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The ladder is divided into multiple sections (base section and fly section) that can slide relative to each other. This segmentation allows the ladder to maintain rigidity when extended while reducing the weight of each individual section, making it easier to maneuver and store.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The ladder transitions from a static rigid structure to a dynamic telescoping structure with movable sections. The fly section slides within the base section and is locked at desired positions, providing both mobility during handling and rigidity during use.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If traditional rung lock mechanisms are used to assist height adjustment, then the ladder can be extended to different lengths, but the mechanisms become bulky and reduce the usable space on the rungs

Engineering Contradiction:

Improveladder extension capabilityVSAvoidusable rung surface area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The rung lock mechanism is extracted from the traditional position on the rung surface and relocated to the side of the ladder structure. This extraction allows the full rung surface to remain accessible and usable, while the locking function is maintained through the side-mounted mechanism that engages with the telescoping sections.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS12435567B2Extension ladder, ladder components and related methods

Publication Date: 2025.10.07 LITTLE GIANT LADDER SYSTEMS LLC

AI summary

A ladder is provided having a base section and a fly section slidably coupled with the base section. The base section includes a first pair of spaced apart rails and a first plurality of rungs extending between and coupled to the first pair of spaced apart rails. The fly section includes a second pair of spaced apart rails and a second plurality of rungs extending between and coupled to the second pair of spaced apart rails. The various rungs may be coupled with their associated rails in an offset relationship such that they are not centered along a longitudinal center axis line of the rails. A rung lock device may be used which includes an arm pivotally coupled with the base section and configured to selectively engage various rungs of the second plurality of rungs to maintain the fly section in a desired position relative to the base section.