Injection Molded Luggage Shell with Integrated Zipper Assembly
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Solution Overview
Problem
Existing luggage cases with injection molded shells face challenges in efficiently and precisely attaching zipper assemblies, leading to malformation, high production costs, and inflexibility in responding to market demand for expandable or non-expandable designs.
Innovation Solution
An injection molded luggage case with a zipper assembly integrated during the molding process, using a tape member with distinct material portions for bonding and abrasion resistance, and a modular expansion zipper assembly that can convert non-expandable to expandable designs post-production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zipper assemblies are attached to injection molded luggage cases using conventional post-molding methods, then the zipper assembly can be securely attached, but the production process becomes complex and time-consuming
Solution Approach 1:
The patent combines the zipper assembly attachment process with the injection molding process itself. The zipper tape is positioned in the mold cavity before injection, and the molten plastic material flows around and bonds to the zipper tape during molding. This merging of processes eliminates separate attachment steps, reduces production complexity, and maintains secure attachment through integral bonding.
Solution Approach 2:
The zipper assembly is positioned and prepared in advance within the mold cavity before the injection molding process begins. The zipper tape is placed in the desired location and orientation, and the mold is closed around it. This preliminary positioning ensures the zipper is correctly situated before the plastic material is injected, eliminating the need for post-molding attachment operations.
2Ease of manufacture
If conventional zipper attachment methods are used, then the zipper can be attached to the luggage case, but manufacturing precision and repeatability are compromised
Solution Approach 1:
The patent replaces mechanical attachment methods (such as stitching, adhesives, or snap-fits) with a chemical bonding mechanism. The injection molded plastic material chemically bonds to the zipper tape through molecular adhesion during the molding process. This substitution provides more precise and repeatable attachment because the bonding occurs uniformly throughout the contact area under controlled mold conditions, eliminating variability associated with mechanical fastening methods.
3Productivity
If production is predetermined based on forecasted demand for specific luggage styles, then manufacturing can be planned, but flexibility to respond to actual market demand is reduced
Solution Approach 1:
The patent enables dynamic production flexibility by allowing the same injection molding process and tooling to produce both expandable and non-expandable luggage cases. The zipper assembly design with the expansion portion allows the final product configuration to be determined at the point of production based on actual demand, rather than requiring separate predetermined production lines for each style. This dynamic adaptability maintains productivity while responding to real-time market needs.
4Productivity
If zipper assemblies are integrated during injection molding, then production efficiency and precision improve, but the tape member requires complex multi-material construction
Solution Approach 1:
The patent applies local quality by giving different portions of the zipper tape different properties. The first portion of the tape (bonding portion) is made of a material that bonds well with the injection molded plastic, while the second portion (visible portion) is made of a different material with desired aesthetic or functional properties. This localized differentiation allows the tape to fulfill multiple requirements within a single component, enabling efficient integration during molding while maintaining the necessary functional and visual qualities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables precise, efficient attachment of zipper assemblies, reduces production complexity and costs, and allows for flexible production to meet market demands by converting luggage cases between expandable and non-expandable styles.
Implementation Method 1
the first portion of the tape member is predominately made of a first material that is compatible with and bonds to the plastic mold material
Data Source
Figure 1A~1C
Figure 1B~2B
Figure 3A
AI summary
A luggage case (102, 102') including an injection molded luggage shell (116, 118, 116', 118') including a zipper assembly (130, 130') attached to the luggage case (102, 102') during the injection molding of each shell (116, 118, 116', 118'). The injection molded shell (116, 118, 116', 118') having a rim portion (132, 134, 132', 134', 145) and having opposing inside (140, 140') and outside (142, 142') surfaces. An elongated zip member (144, 146, 144', 146') including a tape member (148, 148') having opposing first (154, 154') and second (156, 156') surfaces, and opposing inner (150, 150') and outer (152, 152') edges defining a width, with teeth (158, 158') positioned along the inner edge (150, 150'), and defining a length. One opposing surface (154, 156, 154', 156') of at least part of a first portion (160, 160') of the first tape member (148, 148') is in-mould-bonded to at least one opposing surface (140, 142, 140', 142') of the rim portion (132, 134, 132', 134', 145).