Pulp-Molded Paper Lid with Elastic Pre-Compression for Snap-Retention
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Solution Overview
Problem
Conventional pulp-molded paper lids for beverage cups face issues with structural strength, elasticity, and production complexity due to rigid internal sidewalls, permanent deformation, and complex mold assembly requirements, leading to ineffective snap-retention and increased production costs.
Innovation Solution
A pulp-molded paper lid with an elasticity generating device featuring a movable bearing wall and guiding slopes, which pre-compresses and elastically rebounds to securely retain the convex-ridge ring, and a simplified mold design with positive draft angles for efficient thermo-compression forming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional pulp-molded cup lids are made with rigid internal sidewalls for structural support, then structural strength is improved, but permanent deformation occurs during snap-retention leading to ineffective sealing
Solution Approach 1:
The internal sidewall is transformed from a rigid static structure to a dynamic elastic structure. The elastic generating device includes an elastic portion that can dynamically deform during the snap-retention process, allowing the cup lid to adapt to the convex-ridge ring while maintaining structural integrity. This dynamic elasticity enables reliable snap-retention without permanent deformation.
2Device complexity
If conventional pulp-molded cup lids use complex mold assemblies with multiple demolding directions to form latch structures, then structural complexity is improved, but production cost and cycle time increase
Solution Approach 1:
The mold assembly is segmented into a first mold assembly for forming the cup lid body and a second mold assembly for forming the elastic generating device. This segmentation allows each mold assembly to be optimized for its specific function, simplifying the overall mold structure. The elastic generating device is formed as a separate component that can be integrated into the cup lid, eliminating the need for complex integrated mold structures.
Solution Approach 2:
The elastic generating device is pre-formed as a separate component using a dedicated second mold assembly. This preliminary action allows the elastic portion to be precisely formed with the required geometric features before being integrated into the final cup lid product. This approach simplifies the main mold assembly and reduces the production cycle time by avoiding complex in-situ forming operations.
3Object-affected harmful factors
If conventional pulp-molded cup lids use plant fiber materials for environmental friendliness, then biodegradability is improved, but structural strength and elasticity are insufficient for effective snap-retention
Solution Approach 1:
The physical and mechanical parameters of the pulp-molded material are optimized to achieve the required structural strength and elasticity. By controlling the fiber composition, density, and processing parameters during thermo-compression molding, the material properties are enhanced to provide sufficient structural support and elastic deformation capability for effective snap-retention while maintaining environmental friendliness.
Solution Approach 2:
The cup lid employs a composite structure combining pulp-molded material with an integrated elastic generating device. This composite approach leverages the environmental benefits of pulp-molded materials while incorporating specifically designed elastic geometric features that provide the necessary mechanical performance for snap-retention, effectively combining the advantages of both material systems.
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
The solution enhances the structural integrity and snap-retention of the pulp-molded paper lid, simplifies the mold assembly, reduces production costs, and improves automated production efficiency while ensuring consistent quality and higher yield.
Implementation Method 1
the bent end is pre-compressed by preloading of an insertion force of the convex-ridge ring; and, by removing the external pressure, the elasticity generating device is released from the pre-compression to exert preloaded elastic forces
Implementation Method 2
both of the guiding slopes are configured on a basis of an inclined plane principle to advantageously guide a sliding movement of the convex-ridge ring
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 2D~2F
AI summary
A pulp-molded paper lid for a beverage cup and a method for fabricating the same is introduced. While said pulp-molded paper lid bears an external pressure to accommodate a convex-ridge ring of the cup body therein, an elasticity generating device (30) of said pulp-molded paper lid is pre-compressed, by preloading of an insertion force of said convex-ridge ring, to compressively deform along inward directions respectively opposite to radial directions of said pulp-molded paper lid. By removal of said external pressure, a movable bearing wall (32) and an outermost sidewall of said elasticity generating device (30) respectively exert two reversed elastically-rebound forces by a stretched deformation occurring therebetween, for clamp-retaining two opposed sides of said convex-ridge ring. Said elasticity generating device (30) is released from the pre-compression to exert preloaded elastic forces along said radial directions, for strengthening the clamp-retention and avoiding the technical problems of the prior arts.