Hinged Plastic Box Frangible Link First Opening Indicator
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Solution Overview
Problem
Existing plastic boxes with hinged lids lack a reliable first-opening indicator that ensures secure closure while allowing easy user access, as existing solutions often require breaking a frangible part for opening, which may not provide clear indication of previous opening and closure.
Innovation Solution
A plastic box design featuring a single-piece construction with a hinge that includes a protruding tongue or tab, where the hinge parts fold around the axis of articulation, and a frangible link that breaks upon first opening, forming a visible indicator and allowing easy opening by pulling the tab, while maintaining secure closure through complementary reliefs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a frangible part is used in the hinge to prevent easy opening, then the box provides a reliable first-opening indicator, but the opening operation becomes difficult for the user
Solution Approach 1:
The hinge is divided into a stable part (attached to base and lid) and a frangible part (separate element that breaks). This segmentation allows the stable part to maintain reliable closure while the frangible part provides the first-opening indicator function without impeding normal operation.
Solution Approach 2:
A tongue element acts as an intermediary between the user and the frangible part. The user pulls the tongue to initiate opening, which then triggers the frangible part to break. This intermediary makes the opening process intuitive and easy while still providing the security indicator.
2Reliability
If the lid peripheral edge is prevented from being grasped by a peripheral heel, then the box maintains secure closure, but the user cannot easily open the lid
Solution Approach 1:
The tongue serves as a mediator that bypasses the peripheral heel obstruction. Instead of trying to grasp the blocked lid edge, the user pulls the tongue which is accessible and designed for manual operation, initiating the opening sequence without conflicting with the closure security mechanism.
Solution Approach 2:
The opening function is extracted from the lid peripheral edge (which is blocked by the heel) and transferred to the tongue element. This allows the peripheral heel to maintain its closure security function while the tongue provides the opening initiation function.
3Reliability
If the hinge is made frangible to form a first-opening indicator, then opening status can be verified, but the box structure becomes more complex
Solution Approach 1:
The hinge is segmented into a stable part and a frangible part, where the frangible part is a simple separate element (such as a thin wall section or breakable link) rather than a complex mechanism. This keeps the overall structure simple while providing the opening status indication function.
Solution Approach 2:
The frangible part is designed as a simple, inexpensive element meant to break once. It could be a thin plastic wall, a breakable link, or a pre-scored section that easily fractures under pulling force, providing the indicator function without adding significant complexity or cost.
Data Source
Figure 1
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Figure 4~5
AI summary
The box comprises a base (4) and a lid (6) connected by a hinge (8) including at least one hinge portion (10) connected to the lid 6 by a frangible joint (18) configured to break upon the first opening of the lid (6). The box includes a tab (20) extending from the lid (6) and beyond the hinge axis (A), such that when the box is closed, the tab (20) extends outwards from the lid (6) and protrudes beyond the hinge axis (A), pulling on the tab (20) allows the lid (6) to be opened by breaking each frangible joint (18), a portion of the lid (14) of each hinge portion (10) remaining attached to the base (4) and dissociated from the lid (6), protruding.