Tamper-Indicating Band With Sloping Teeth For Low Removal Torque
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Solution Overview
Problem
Current container/closure systems are difficult for elderly and arthritic users to open due to high removal torques, and they often experience 'back-off' issues leading to leakage and tampering concerns, especially when using plastic containers that shrink during retort conditions, compromising hermetic seals.
Innovation Solution
A closure assembly with a tamper-indicating band featuring sloping teeth and rupturable bridges, where the teeth on the band are angularly offset from the container's teeth, allowing for lower removal torque and providing audible feedback, while maintaining 'anti-back off' features through an interference fit with a retaining bead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is used to lock the tamper-indicating band in place, then the band provides tamper resistance, but the removal torque becomes too high for elderly and arthritic users
Solution Approach 1:
The locking mechanism is segmented into discrete engagement points along the circumferential direction. The band and closure have corresponding teeth that engage at multiple discrete positions, allowing the band to be locked securely while providing defined release points that reduce the torque needed for removal.
Solution Approach 2:
The locking mechanism uses partial engagement of the teeth rather than complete circumferential locking. The teeth engage at specific discrete positions providing sufficient tamper resistance, but the partial nature of the engagement allows easier removal compared to full circumferential locking.
2Ease of operation
If the closure allows free rotation before band breakage, then the opening force is separated from the band removal force, but the closure becomes subject to back-off and possible leakage
Solution Approach 1:
The sloping teeth are configured to provide preliminary anti-back-off action during the opening process. As the closure rotates, the sloping surfaces of the teeth progressively engage, creating a self-locking effect that prevents back-off and maintains seal integrity until the band is intentionally broken.
Solution Approach 2:
The locking mechanism transitions from a static locked state to a dynamic breaking state. The sloping teeth allow progressive engagement during normal operation to prevent back-off, but are designed to disengage and allow band breakage when sufficient force is applied, providing dynamic control over the opening process.
3Strength
If conventional metal caps are used on plastic containers, then the cap provides structural strength, but the dissimilar expansion causes loss of hermetic seal during retort conditions
Solution Approach 1:
The closure is designed with adjustable geometric parameters including thread pitch, tooth configuration, and engagement depth. These parameters can be optimized to accommodate the thermal expansion characteristics of plastic containers during retort, maintaining both structural strength and hermetic seal integrity.
Solution Approach 2:
The closure system combines the plastic closure body with a metal or rigid tamper-indicating band. This composite structure provides the structural strength needed for retort conditions while the plastic portion can accommodate thermal expansion, maintaining seal integrity throughout the processing cycle.
4Reliability
If high torque is applied during initial capping to maintain hermetic seal, then the seal integrity is improved, but the cap cannot be easily twisted off following retort
Solution Approach 1:
The sealing and locking functions are segmented into separate mechanisms. The hermetic seal is provided by the threaded engagement and gasket, while the locking function is provided by the discrete teeth engagement. This segmentation allows the seal to be maintained at moderate torque while the locked teeth provide additional security without increasing removal difficulty.
Solution Approach 2:
The locking teeth provide partial locking action rather than complete circumferential locking. This partial engagement maintains sufficient seal integrity during retort but does not create excessive friction that would prevent easy removal after processing.
5Reliability
If ratchet teeth are exactly aligned on container and closure, then the teeth engage properly, but significant torque is still needed to break the tamper band bridges
Solution Approach 1:
The teeth on the closure are asymmetrically positioned relative to the container teeth. This asymmetric arrangement creates defined engagement points that provide reliable locking during normal operation but create stress concentration points that facilitate easier band breakage when opening force is applied.
Solution Approach 2:
The teeth engage at discrete partial positions rather than continuous circumferential engagement. This partial engagement provides sufficient reliability for tamper resistance but creates natural break points in the tamper band that require less torque to fracture during opening.
Data Source
AI summary
An assembly includes a container and a closure. The closure includes a tamper-indicating band having a plurality of sloping teeth. Each of the sloping teeth of the tamper-indicating band has an engagement surface that is engageable with one of the engagement surfaces of the sloping teeth of the container. The sloping teeth on the tamper-indicating band are configured such that when one of the teeth on the tamper-indicating band completely engages one of the teeth on the exterior surface of the neck of the container, the engagement surface of at least one of the other sloping teeth on the tamper-indicating band is free from engagement with the engagement surfaces of the sloping teeth of the container and the engagement surface of at least one of the other sloping teeth of the container is free from engagement with the engagement surfaces of the sloping teeth on the tamper-indicating band.