Hidden Seam Metal Container End Attachment
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Solution Overview
Problem
The existing methods for attaching an end to a metal container, such as double seaming, result in an aesthetically undesirable bulge and can damage the internal lacquer when trying to achieve a tight fit, which is a concern for high-end decorative products.
Innovation Solution
A method involving a curling tool and reaction tools to curl the end's lip around the container's curled lip, forming a 'hidden' seam without requiring a tight fit, allowing for automation and maintaining the internal lacquer's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a double seaming process is used to attach the end to the body, then the attachment strength is improved, but the aesthetic appearance deteriorates due to the bulging seam
Solution Approach 1:
The invention extracts the visible bulge from the attachment process by using a different mechanism (curling lips together) that does not create external deformation. The attachment is achieved through interlocking curls rather than external folding, removing the aesthetic defect while maintaining strength.
Solution Approach 2:
Instead of folding the end over the body externally (double seaming), the invention inverts the approach by curling the lips inward and interlocking them from the inside. This reversal of the attachment mechanism eliminates the external bulge while achieving secure attachment.
2Reliability
If the end is inserted tightly into the body to form a tight closure, then the sealing quality is improved, but the internal lacquer is damaged due to scratching
Solution Approach 1:
The invention performs preliminary curling of the lips before insertion. The lips are pre-curved to match the insertion path, allowing smooth entry without forcing the end against the lacquer-coated interior walls, thus preventing scratching while ensuring tight closure.
Solution Approach 2:
The invention changes the geometric parameters of the lips (curving them in advance) to accommodate the insertion process. This parameter modification allows the end to be inserted without excessive force or friction that would otherwise scratch the internal lacquer.
3Reliability
If the end is inserted at an angle to achieve tight fit, then the sealing quality is improved, but the process complexity increases due to levelling requirements
Solution Approach 1:
The lips are pre-curved during manufacturing to the exact angle needed for insertion. This preliminary preparation eliminates the need for complex levelling operations during assembly, as the end naturally guides itself into the correct position through the curved lip geometry.
4Shape
If a traditional curling process is used to attach the end, then the seam becomes hidden, but the process is difficult to automate
Solution Approach 1:
The attachment process is segmented into distinct, standardized steps (positioning, curling, interlocking) that can be independently controlled and automated. The separation of these operations allows for precise robotic manipulation and sensor feedback integration.
Solution Approach 2:
The invention employs dynamic tooling that can adapt its curvature and applying force during the curling process. This dynamic capability allows automated systems to accommodate variations in material properties and achieve consistent results through real-time adjustment of curling parameters.
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
This method enables the attachment of a metal end to a container with a 'hidden' seam, preventing damage to the internal surface and facilitating automation, while improving the aesthetic appeal by eliminating the bulge associated with traditional double seaming.
Implementation Method 1
bringing a curling tool through the container body into contact with said upstanding lip of the end and applying a force to that lip, via the curling tool, in order to curl the upstanding lip around the curled lip of the body
Implementation Method 2
positioning a reaction tool in contact with the end and with said curled lip of the body in order to counteract a force applied by the curling tool
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
A method of attaching a metal end (7) to a metal container body (6) in order to close an opening in the body, wherein the body (6) has a curled lip at least partially surrounding the opening and the end (7) has an upstanding lip extending at least partially around a periphery thereof. The method comprises locating the end (7) within the body (6) at or near said opening, bringing a curling tool (8) into contact with said upstanding lip of the end (7) and applying a force to that lip, via the curling tool (8), in order to curl the upstanding lip around the curled lip of the body (6) to form interlocking curls.