Two-piece twist-off lid with elastic disc and plastic ring
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Solution Overview
Problem
Existing screw-type lids for glass storage jars require excessive force to open and are prone to mechanical damage and deformation, leading to rust and reduced reusability, while hermetic sealing mechanisms with plastic components face durability issues due to excessive stress and microcracks.
Innovation Solution
A two-piece twist-off lid design featuring a sheet metal covering disc with a curled edge and a heat-resistant polycarbonate plastic threaded ring with blade-like protrusions, where the ring's upper part extends radially inward to form a retainer conforming to the disc's curl, reducing stress on components and ensuring a long-lasting hermetic seal, and allowing for multiple use with replaceable discs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid body lid made of soft tinplate with spiral protrusions is used, then hermetic sealing is achieved, but excessive force is required to open and mechanical damage occurs
Solution Approach 1:
The lid is divided into two separate parts: a covering disc made of soft tinplate for hermetic sealing, and a threaded ring made of hard plastic for providing opening torque. This segmentation allows each part to perform its specialized function without compromise - the soft disc seals reliably while the hard ring resists deformation during opening.
Solution Approach 2:
The invention combines two different materials with complementary properties: soft tinplate (Rockwell hardness 51-54) for the covering disc to ensure hermetic sealing, and hard plastic (Rockwell hardness 60-70) for the threaded ring to provide structural strength and ease of opening. This composite approach resolves the contradiction between sealing reliability and ease of operation.
2Object-affected harmful factors
If protective varnish coating is applied to the cylindrical side part, then mechanical damage is reduced, but rust still appears under high temperature and aggressive media
Solution Approach 1:
The covering disc made of soft tinplate is designed as a disposable component that is replaced after each use. This eliminates the need for long-term corrosion protection, as the disc is discarded before rust can develop. The threaded ring made of hard plastic is inherently rust-resistant and can be reused multiple times.
3Reliability
If an inwardly bent upper edge of plastic ring is used for hermetic sealing, then sealing force is provided, but microcracks form and fracturing occurs during reuse
Solution Approach 1:
The hermetic sealing function is extracted from the plastic threaded ring and assigned to the metal covering disc. The ring's upper edge is made straight rather than bent, eliminating the stress concentration point that causes microcracks. The covering disc with its curled edge provides the hermetic sealing through contact with the jar neck edge, while the ring simply provides threading and opening torque.
4Reliability
If continuous compressive force is transmitted from plastic ring through bent edge to metal disc, then hermetic seal is maintained, but stress on ring components increases
Solution Approach 1:
The lid structure is segmented into a covering disc that provides hermetic sealing through its curled edge contact with the jar neck, and a threaded ring that provides opening torque through blade-like protrusions. The retainer on the ring engages with the curled edge to prevent lateral displacement, while the sealing force is distributed through the disc's contact with the jar neck edge rather than concentrated on the ring's bent upper edge.
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 design enables easy opening without excessive force, enhances the durability of the lid components, and extends the shelf life of the seal, allowing the threaded ring to withstand up to 10,000 cycles with reinforced rings capable of 30,000 cycles, while maintaining hermeticity and allowing for decorative elements on the ring.
Implementation Method 1
the round curl (3) of the covering disc, which compresses elastically upon contact with the retainer (10) and creates an additional contact force between the two pieces of the lid
Data Source
Figure 1
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AI summary
A two-piece twist-off lid for glass storage jars comprises of two separate parts: a covering disk and a threaded ring. The edge of the covering disk is curled upward to form a circular curl and is bent outward to form an annular channel for placing a seal and for seating the covering disc on the edge of the jar neck. The covering disk is made of elastic tinplate having a thickness of 0.08-0.16 mm and Rockwell hardness of 58-64. The cylindrical threaded ring is made of a plastic material and comprises retaining thread members for locking the ring on the jar neck. Said thread elements are embodied in the form of blade-like protrusions arranged at an angle along the circumference on the inner surface of the ring. The upper part of the threaded ring extends radially inward to form a retainer for the edge of the covering disk, wherein said retainer geometrically conforms to the curl of the covering disk. The design features of the proposed two-piece twist-off lid for glass storage jars provide a high degree of hermetic sealing, while the operating characteristics are consistent with the conditions of multiple use of the threaded ring as a component of the lid, and allow for the replacement of the covering disk.