Cap Knurling Design for Low-Profile Closure Grip
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Solution Overview
Problem
Existing closure structures with low cap heights present difficulties in gripping and rotating due to a small surface area for user interaction, making it hard to open the cap easily.
Innovation Solution
The closure structure features a cap with a top plate portion and a tube portion divided into a main portion and a tamper evidence ring portion. The outer-circumferential surface of the main portion includes an upper knurl and a side knurl, along with a smooth lower region, to enhance grip and rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the cap height is reduced to suppress the height of the closure structure, then the height parameter is improved, but the gripping surface area is reduced making it difficult to rotate the cap
Solution Approach 1:
The outer-circumferential surface of the cap is divided into different regions with different properties: an upper grip region with knurl projections for enhanced grip, a middle smooth region for clean appearance and sealing contact, and a lower grip region with knurl projections for additional grip. This local differentiation allows the cap to maintain compact height while providing adequate gripping surfaces.
Solution Approach 2:
Instead of increasing cap height vertically to provide more gripping surface area, the invention utilizes the circumferential dimension by adding knurl projections that extend radially outward from the cap surface. This transforms the gripping interface from a two-dimensional surface to a three-dimensional structure with increased effective grip area without increasing overall height.
2Ease of operation
If knurl projections are added to increase gripping surface area, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The cap structure is segmented into distinct functional zones: top seal portion, upper grip region with knurls, middle smooth region, and lower grip region with knurls. Each segment serves a specific function, allowing the design to achieve multiple objectives (sealing, gripping, aesthetics) without excessive overall complexity.
Solution Approach 2:
The knurl projections serve multiple functions simultaneously: they provide enhanced gripping surfaces for user operation, create visual texture for aesthetic appeal, and maintain structural integrity of the cap. The smooth middle region serves dual purposes of providing a clean visual appearance and creating a sealing contact surface.
Data Source
AI summary
A closure structure includes a cap, and a spout having a mouth portion to which the cap is attached. The cap includes a top plate portion and a tube portion. The tube portion extends downward from a periphery of the top plate portion. The tube portion is divided into a main portion and a tamper evidence ring portion. The tamper evidence ring portion is connected to the main portion by a bridge. An inner-circumferential surface of the main portion is formed with a threaded portion. An outer-circumferential surface of the main portion is formed with an upper knurl and a side knurl. The upper knurl is formed at a position including an upper end of the outer-circumferential surface. The side knurl is formed at a position lower than the upper knurl.