Three-Section Mast Assembly with Rear Pull System
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Solution Overview
Problem
Existing masts for industrial trucks, particularly reach trucks, face challenges in achieving maximum payload height with sufficient stiffness while maintaining a compact design, as they often lack effective rear pull systems and efficient force distribution, leading to reduced rigidity and potential deflection under heavy loads.
Innovation Solution
A mast design featuring three interconnected mast frames with a rear pull system on the center mast, combined with a roller guide and strategically placed lifting cylinders and traction mechanisms, enhances stiffness and stability by distributing forces effectively and preventing lateral deflection, allowing for heavier loads to be lifted safely at greater heights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mast is designed to lift large payloads to great heights, then the lifting capacity and height are improved, but the mast requires greater stiffness and structural complexity which increases device complexity
Solution Approach 1:
The patent implements a nested mast structure where the inner mast is positioned within the middle mast, which is in turn positioned within the outer mast. This nested arrangement allows multiple mast sections to occupy overlapping spatial volumes, achieving the required lifting height and payload capacity while maintaining a compact overall structure and reducing device complexity.
2Volume of stationary object
If the mast structure is made more compact to optimize warehouse space, then the volume occupied is reduced, but the stiffness and rigidity may be compromised leading to potential deflection under heavy loads
Solution Approach 1:
By nesting the inner mast within the middle mast within the outer mast, the patent achieves a compact volume occupation while maintaining the structural integrity of each individual mast section. Each mast section retains its full stiffness characteristics, and the nested arrangement ensures that the required lifting height is achieved without excessive overall volume.
Solution Approach 2:
The patent applies different structural characteristics to different parts of the mast system. The profile rails are specifically designed with optimized cross-sectional geometries (such as I-beams or box sections) to provide high stiffness-to-weight ratios. The crossbeams are strategically positioned and dimensioned to provide local reinforcement where needed, ensuring overall mast stiffness while maintaining compact dimensions.
3Device complexity
If traditional mast designs without rear pull systems are used, then the structure is simpler, but the stiffness and force distribution are insufficient leading to reduced stability under heavy loads
Solution Approach 1:
The patent divides the mast into multiple independent but interconnected sections (outer mast, middle mast, inner mast), each with its own structural integrity. The rear pull systems are independently provided on the middle and inner masts, creating segmented force distribution paths that enhance overall mast stability while allowing each section to be optimized individually.
Solution Approach 2:
The patent introduces rear pull systems that act in a different spatial dimension (rearward direction) compared to traditional front-only support systems. This dimensional addition creates a more balanced force distribution throughout the mast structure, improving stability under heavy loads by counteracting forward bending moments with rearward tensile forces.
Data Source
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Figure 3
AI summary
The invention relates to a mast assembly for an industrial truck, especially for a moving mast reach truck, comprising a load-carrying means, three mast frames each having two profile rails that are interconnected via at least two cross-beams, and a lifting mechanism that can lift the three mast frames relative to each other. The three mast frames are designed as an inner mast, a center mast and an outer mast, the inner mast being supported by the center mast and the center mast being supported by the outer mast, the center mast having a section reinforcement arranged on the side of the center mast facing the vehicle.