Snap-Fit Tethered Cap Assembly for Twist-Free Opening
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Solution Overview
Problem
Existing closure assemblies face challenges in providing a robust and efficient connection between the tether and the cap body, especially in mass production, which can lead to the cap body being separated from the container and ending up in the environment.
Innovation Solution
A snap fit connection is established between the tether and the cap body using breakable snap fit bridges, allowing for a rotatable connection that ensures the cap body can be removed without twisting the tether, and the tether remains integrated with the cap body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tether is integrally moulded to the cap body, then the connection is strong and reliable, but the manufacturing process becomes complex and difficult to implement in mass production
Solution Approach 1:
The tether connection is divided into separate components: a tether portion and a cap body portion with distinct snap fit features. The tether portion includes a snap fit protrusion that engages with a snap fit recess in the cap body, allowing independent manufacturing and assembly of these components while maintaining a reliable connection.
Solution Approach 2:
The snap fit features are pre-formed during the moulding process of the tether and cap body respectively. The snap fit protrusion is integrated into the tether portion during its formation, and the snap fit recess is prepared in the cap body, enabling quick assembly without requiring complex post-moulding operations.
2Reliability
If the tether is deformed to permanently connect to the cap body, then the connection is secure, but the manufacturing precision and quality control become difficult
Solution Approach 1:
The connection mechanism is segmented into a male snap fit protrusion on the tether and a female snap fit recess in the cap body. This eliminates the need for deformation operations while providing a secure mechanical interlock that is easy to control and inspect for manufacturing quality.
Solution Approach 2:
The snap fit features are designed to self-align and self-engage during assembly. The protrusion automatically fits into the recess without requiring precise manual positioning or deformation operations, reducing the need for complex quality control measures.
3Ease of operation
If the cap body is removed by rotational movement, then the opening action is efficient, but the tether twists and rotates along with the cap body causing wear and potential failure
Solution Approach 1:
The snap fit connection provides a localized pivot point between the tether and cap body. This allows the cap body to rotate during opening while the tether remains relatively stationary, concentrating the rotational movement at the snap fit joint rather than along the entire tether length, thereby reducing wear and maintaining durability.
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
A closure assembly comprising a cap and an article with a neck. The plastic moulded cap being secured to the neck of the article and comprising a cap body. The cap comprises a tether which has at a second end thereof a tether snap fit portion, the cap body has a corresponding cap body snap fit portion. In an initial configuration the tether snap fit portion is connected to the cap body via breakable bridges, in an assembled configuration a snap fit connection is established between the tether snap fit portion and the cap body snap fit portion.