Fire Ladder Basket Pivot Structure for Single-Axle Reach
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Solution Overview
Problem
Traditional quint configuration fire trucks require a second rear axle to increase the horizontal reach and vertical extension height of the aerial ladder, leading to increased weight, difficulty in maneuverability, and higher manufacturing costs.
Innovation Solution
A ladder assembly for a fire apparatus that includes a basket with a subfloor frame assembly, upper frame assembly, and actuators that allow the basket to pivot relative to the ladder mount, enabling increased vertical extension height and horizontal reach without the need for a tandem rear axle, thus reducing weight and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a second rear axle is added to increase horizontal reach and vertical extension height, then the aerial ladder performance is improved, but the vehicle weight increases and maneuverability deteriorates
Solution Approach 1:
The basket is divided into multiple structural components (subfloor frame assembly, upper frame assembly, door assemblies) that can be independently designed and optimized. This segmentation allows the structure to achieve required strength and reach while using lighter materials and more efficient load distribution, eliminating the need for a second rear axle.
Solution Approach 2:
The basket design incorporates three-dimensional spatial optimization with the upper frame assembly extending upward from the subfloor frame, creating vertical clearance and horizontal reach simultaneously. The angled door assemblies (oriented at angles relative to the front portion and side portions) provide structural support while maximizing interior space and access, achieving performance goals without additional axles.
2Length of moving object
If a second rear axle is added to increase horizontal reach and vertical extension height, then the aerial ladder performance is improved, but the manufacturing cost increases
Solution Approach 1:
The basket incorporates dynamic elements including movable door assemblies that can open and close, and a pivotable platform extension that adjusts between stored and extended positions. This dynamic design allows a single, versatile structure to accommodate various operational requirements, reducing the need for multiple specialized components and lowering manufacturing costs.
Solution Approach 2:
The upper frame assembly serves multiple functions: it provides structural support for the basket, forms the mounting structure for the door assemblies, and creates the vertical framework necessary for achieving extended height. This multi-functionality reduces the total number of components needed, simplifying manufacturing and reducing costs.
3Strength
If the basket structure is strengthened to support increased reach and height, then the structural integrity is improved, but the weight increases
Solution Approach 1:
The basket employs composite construction combining the subfloor frame assembly (providing base structural support) with the upper frame assembly (providing vertical and lateral support). This composite structure distributes loads efficiently across different material zones, achieving required structural integrity while minimizing overall weight through optimized material placement and selection.
Solution Approach 2:
The subfloor frame assembly is designed and positioned beforehand to provide a stable foundation that pre-loads and stabilizes the structure before the upper frame assembly is attached. This preliminary structural preparation ensures that the final assembled basket achieves maximum structural efficiency with minimal material, reducing weight while maintaining integrity.
Data Source
AI summary
A ladder assembly includes a ladder and a basket. The ladder has a first end and an opposing second end configured to couple to the fire apparatus. The basket is coupled to the first end of the ladder. The basket includes a subfloor frame assembly, a floor panel coupled to the subfloor frame assembly, and an upper frame assembly extending upward from and around a periphery of the floor panel. The upper frame assembly includes a front portion, a rear portion, opposing side portions coupled to the rear portion; and a pair of doors extending between the front portion and the opposing side portions. The pair of doors are positioned proximate front corners of the basket and oriented at an angle relative to the front portion and the opposing side portions.