Bonded Tamper-Evident Closure Without Loose Break-Off Parts
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Solution Overview
Problem
Existing closures with integrally moulded breakable connections face issues such as compromised breakable connections during initial closure and loose parts after first opening, while designs without well-defined connections are difficult to manufacture using glue dots or welding.
Innovation Solution
A closure with a tamper-evident lug welded to the lid or annular base, where the frangible connection is broken at first opening, ensuring the lug remains fixed and visible, and is manufactured by injection moulding with ultrasonic welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the locking tab is moulded in the locking position with integrally formed breakable connection portions, then the connection portions can be dimensioned in a well-defined manner, but the breakable connection may be compromised during initial closure when force is applied to close the lid
Solution Approach 1:
The closure is pre-assembled in the open state with the locking tab in its locked position, and the breakable connection is pre-formed between the locking tab and lid. This preliminary arrangement ensures that the breakable connection is not subjected to compromising forces during initial closure, as the lid and base are moulded separately and then assembled with the locking mechanism already in place.
2Reliability
If the tear tab is removed by breaking welding points and tearing off along weakened hinges, then tamper evidence is provided, but the tear tab becomes a loose part which may get lost
Solution Approach 1:
The locking tab and lid are integrally formed as a single piece through injection moulding, eliminating the separate tear tab that becomes loose. The breakable connection is integrated into the locking mechanism itself, so when the connection breaks, the locking tab remains attached to the lid, preventing loss of parts while maintaining tamper evidence.
Solution Approach 2:
The breakable connection is designed as a distinct frangible section within the integral structure, allowing it to break at a predetermined location while keeping the main locking tab attached to the lid. This segmentation provides tamper evidence without creating loose parts.
3Strength
If the locking tab reaches over the edge between the deck and skirt of the lid, then enhanced locking is achieved, but the closure cannot be formed with the locking tab in a locking state
Solution Approach 1:
The locking tab is pre-positioned in the locked state during assembly, with the breakable connection pre-formed between the locking tab and lid. The lid and base are then moulded separately and assembled in this preliminary locked configuration, allowing the locking tab to reach over the edge for enhanced locking while maintaining manufacturability through separate moulding and assembly.
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 solution provides a secure and visible indication of tampering without loose parts, while allowing easy manufacturing through injection moulding and ultrasonic welding.
Implementation Method 1
a) The annular base, the lid and the locking member are each injection moulded from a plastic material. b) After injection moulding, the lid is positioned in a closed state on the annular base and the locking member is positioned in a locked state... Finally, the tamper-evident lug is attached to the attachment surface of the lid or, alternatively, the annular base by an ultrasonic welding tool and weld it to the attachment surface.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A closure (1) for a container comprises an annular base (2) to be fixed to the upper rim of a container and a lid (3). The lid (3, 103) is adapted to be moved to an open position, in which access is gained to the container. A locking member is attached to the base (2, 102) and to the lid (3, 103) so as to lock the lid (3, 103) relative to the base (2, 102) such that movement of the lid (3, 103) relative to the annular base (2, 102) is prevented. The locking member comprises at least one tamper-evident lug (20, 120) welded to an attachment surface (19) of the lid (3) or the annular base (102) and a frangible connection (21, 121) integrally adjoining the tamper-evident lug (20, 120).