Cast Push Carriage for Narrow-Aisle Forklifts
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Solution Overview
Problem
Narrow-aisle forklifts with welded push carriages face high stress values in weld seams due to large operational forces, leading to potential structural weaknesses and safety concerns.
Innovation Solution
Designing the push carriage as a one-piece cast component with an L-shaped hollow profile, featuring variable wall thicknesses and rounded transitions, and integrating flange plates for secure attachment to the mast and load-carrying means, produced through a casting process to optimize stress distribution and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the push carriage is designed as a welded assembly from several plate-like components, then the structural complexity is increased and manufacturing is more difficult, but the stress concentration in weld seams becomes the critical weakness
Solution Approach 1:
The patent merges multiple plate-like components into a single monolithic push carriage structure. This eliminates the need for weld seams between components, directly resolving the technical contradiction by removing the weak point (weld seams) while simplifying the overall structure. The monolithic design ensures continuous material flow and eliminates stress concentration at joints.
Solution Approach 2:
While the overall structure is monolithic, the patent introduces internal hollow profile sections with optimized wall thicknesses that segment the material distribution. This allows thicker walls in highly stressed areas and thinner walls in low-stressed areas, achieving efficient stress distribution within the single-component structure.
2Manufacturing precision
If the push carriage is designed as a welded assembly, then manufacturing precision can be achieved through welding, but the stress values in the smallest profile cross-section of welds become excessively high
Solution Approach 1:
By combining all components into a single monolithic structure, the patent eliminates weld seams entirely. This removes the stress concentration problem inherent in welded assemblies while maintaining manufacturing precision through monolithic casting or forging processes that can achieve high dimensional accuracy without welding operations.
3Reliability
If the push carriage is designed as a one-piece cast component with variable wall thicknesses, then the stress distribution is optimized and safety is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies local quality by implementing variable wall thicknesses within the monolithic push carriage structure. Thicker walls are positioned in highly stressed areas to increase load-bearing capacity and safety, while thinner walls are used in low-stressed areas to reduce weight and material usage. This localized optimization enhances reliability without requiring complex assembly processes.
Solution Approach 2:
The patent changes the geometric parameters of the push carriage by introducing hollow profile sections with variable wall thicknesses. This parameter optimization allows the structure to adapt to local stress requirements, achieving higher safety factors in critical areas while maintaining overall structural efficiency. The casting process enables these parameter variations to be integrated into a single component.
4Adaptability or versatility
If the push carriage is designed as a welded assembly, then assembly flexibility is improved, but the structural integrity is compromised due to weld seam weaknesses
Solution Approach 1:
By merging all components into a single monolithic structure, the patent eliminates weld seams that compromise structural integrity. The continuous material flow ensures uniform structural properties throughout the push carriage, enhancing stability and reliability. Assembly flexibility is maintained through the modular design of the overall forklift system, where the monolithic push carriage functions as a reliable integrated unit.
Data Source
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AI summary
Industrial truck (1), in particular a narrow-aisle forklift truck, with a lifting mast (4) and a load handling device (6) arranged on the lifting mast (4) that can be raised and lowered, wherein the load handling device (6) is designed as a pivoting push fork (20) which has a push slide (12) movable in the transverse direction (Q) of the vehicle on the lifting mast (4). The push slide (12) is designed as a one-piece cast component.