Plastic Vial Cap with Elastic Skirt Ribs
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Solution Overview
Problem
Plastic-made caps for vials struggle to maintain a tight seal, especially when used with glass-made vials that have large dimensional errors, leading to potential separation of the cap from the vial during heat sterilization or other treatments.
Innovation Solution
A plastic-made cap design featuring a top wall with a cylindrical skirt having ribs that can elastically deform to fit over the vial lip, with engagement claws and recessed portions to enhance securement, allowing for absorption of dimensional errors and prevention of cap separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a plastic-made cap is used instead of an aluminum-made cap, then the problems of aluminum particles and segregated disposal are eliminated, but the engagement with the vial becomes loose due to lower deformability
Solution Approach 1:
The patent applies this principle by designing the plastic cap with a flexible skirt portion that can elastically deform during engagement with the vial lip. The skirt portion is made of elastic-plastic material that allows temporary deformation to accommodate dimensional variations in the vial lip, then maintains continuous contact pressure to ensure tight engagement. This flexibility compensates for the inherently lower deformability of plastic compared to aluminum while preventing cap separation.
Solution Approach 2:
The patent applies this principle by changing the dimensional parameters of the cap, specifically making the inner diameter of the skirt portion larger than the outer diameter of the vial lip. This dimensional mismatch is intentional and allows the elastic skirt portion to deform and conform to the vial lip, creating a tight engagement without requiring the cap material itself to be highly deformable like aluminum.
2Reliability
If the dimensional accuracy of the vial is improved to enable tight engagement of the plastic cap, then the engagement reliability improves, but the manufacturing cost and complexity increase significantly
Solution Approach 1:
The patent applies this principle by using the flexible skirt portion to accommodate dimensional variations in the vial lip. The elastic-plastic material allows the skirt to deform and conform to the actual dimensions of the vial lip, which may vary within normal manufacturing tolerances. This eliminates the need for high-precision vial manufacturing while maintaining reliable engagement.
Solution Approach 2:
The patent applies this principle by intentionally designing the cap with parameters that accommodate variation rather than requiring precise control. The inner diameter of the skirt is deliberately made larger than the vial lip outer diameter, and the height and thickness of the skirt are optimized to provide sufficient elastic deformation capability to absorb dimensional errors.
3Reliability
If the engagement between the cap and vial is made tighter, then the separation prevention improves, but the capping process becomes harder and requires excessive force
Solution Approach 1:
The patent applies this principle by using the flexible skirt portion to achieve tight engagement through elastic deformation rather than rigid forcing. The skirt material is designed to deform easily during engagement, accommodating the vial lip geometry and creating a tight fit without requiring excessive capping force. The flexibility allows the cap to conform to the vial rather than forcing the vial to conform to the cap.
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 cap effectively absorbs dimensional errors of the vial, ensuring a tight seal and preventing cap separation, even with glass-made vials, thereby improving the percentage of acceptable caps and maintaining capping performance without requiring excessive force.
Implementation Method 1
the skirt portion is provided on an inner wall thereof with at least two ribs formed at an angular interval in a direction perpendicular to the top wall portion such that, upon application of the cap onto the lip with the opening of the vial being sealed with the plug, the ribs can be elastically deformed to facilitate the application of the cap onto the lip and further to prevent separation of the cap from the lip
Data Source
AI summary
A plastic-made cap for a vial having a lip, the cap being useful as a separation-preventing cap for a plug that seals up an opening of the vial, includes a top wall portion having an outer circumference and centrally defining an opening, and a cylindrical skirt portion extending downwardly from the outer circumference of the top wall portion and being open at its lower end. The skirt portion has an inner diameter (a) greater than an outer diameter (b) of the lip of the vial. The skirt portion is provided on its inner wall with plural ribs formed in a direction perpendicular to the top wall portion. The plural ribs are arranged in pairs at equal angular intervals between the respective pairs of ribs. Further, engagement claws are arranged between the respective pairs of ribs such that the engagement claws can be brought into engagement with an underside of the lip of the vial.