Pull-Rod Luggage Frame Integrated Skeleton Design
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Solution Overview
Problem
Existing pull-rod luggage cases have weak structural connections between the pull rods and the shell, leading to potential damage under longitudinal forces and compression, which affects the telescopic function.
Innovation Solution
A frame for the pull-rod luggage case comprising a pair of pull rods, castor seats, an upper beam, a lower beam, and a handle, integrated as a skeleton to reinforce structural strength by being fixedly connected to the shell's periphery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pull rods are fixed to the shell merely through pull rod fixtures at the lower ends, then the device complexity is reduced and ease of manufacture is improved, but the connection strength and structural reliability deteriorate under longitudinal pulling forces
Solution Approach 1:
The patent merges the pull rod support function with the frame structure by integrating pull rod fixtures into the frame beams. The frame beams serve dual purposes: providing structural support for the shell and anchoring the pull rods through embedded fixtures, thereby combining two separate functions into one integrated structure that achieves both strength and manufacturability
Solution Approach 2:
The patent transitions from a single-point connection (lower end only) to a distributed multi-point connection system. The pull rod fixtures are positioned at multiple locations along the frame beams, distributing the connection points across different spatial dimensions, which enhances overall connection strength while maintaining manufacturing simplicity
2Device complexity
If the pull rods are fixed merely through pull rod fixtures at the lower ends, then the device complexity is reduced, but the reliability of the telescopic function deteriorates under compression from heavy objects
Solution Approach 1:
The frame structure merges the support function for heavy loads with the pull rod mounting function. The frame beams provide structural rigidity to resist compression from heavy objects while simultaneously serving as the mounting structure for the pull rod fixtures, achieving both reliability and simplicity
Solution Approach 2:
The frame structure provides beforehand cushioning by creating a rigid skeletal framework that pre-resists compression forces before they can deform the pull rods. The frame beams act as structural cushions that absorb and distribute compressive loads, protecting the telescopic mechanism from damage
3Strength
If an integrated skeleton frame is used to reinforce structural strength, then the strength and reliability are improved, but the device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The frame beams serve multiple universal functions: providing structural support for the shell, anchoring the pull rod fixtures, and maintaining the geometric relationship between components. This multi-functionality reduces the need for separate structural elements, achieving high strength without proportionally increasing complexity
Solution Approach 2:
The frame structure likely employs composite construction methods, combining different materials or structural forms to achieve high strength-to-weight ratio. The integration of fixtures into the frame beams creates a composite structural system that maximizes strength while minimizing the number of discrete components
4Ease of operation
If the pull rods are fixed merely through pull rod fixtures at the lower ends, then the ease of operation is maintained, but the stability of the pull rod alignment deteriorates under longitudinal forces
Solution Approach 1:
The patent adds stability in the longitudinal dimension by distributing fixtures along the length of the frame beams rather than concentrating them at a single point. This spatial distribution creates a stable geometric configuration that maintains pull rod alignment under operational forces while preserving ease of operation
Data Source
AI summary
A frame for a pull-rod luggage case, including pair of pull rods parallel to each other, a pair of castor seats, an upper beam, a lower beam, and a handle; each of the pull rods at least includes an outer rod and an inner rod telescopically positioned in and out of the outer rod; a lower end of each outer rod is connected to a corresponding castor seat; each of two ends of the handle is fixedly connected with an upper end of a corresponding inner rod; outer rods, the upper beam, and the lower beam define a skeleton.