Double Container Mouth Structure to Prevent Drop-Test Cracking
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Solution Overview
Problem
Existing double containers face issues such as cracking in contact projections during low-temperature drop tests, unintentional rotation of inner bags leading to lifting, and inefficient, space-consuming manufacturing processes.
Innovation Solution
The double container design includes a contact projection with a reinforcing part to prevent cracking, a protruding ridge and groove configuration to prevent unintentional rotation, and a molding system with integrated preform supply, heating, and blow molding devices for efficient, space-saving production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the contact projection is formed by direct blow molding, then the manufacturing process is simplified, but cracking occurs in the contact projection during low-temperature drop tests
Solution Approach 1:
The contact projection is divided into an upper wall and a lower wall that can rotate relative to each other. The lower wall remains fixed while the upper wall rotates to absorb impact energy during drops, preventing cracking while maintaining the simplicity of direct blow molding formation
Solution Approach 2:
The contact projection is designed with dynamic capability where the upper wall can rotate relative to the lower wall during impact events. This dynamic response allows the structure to absorb energy from drops without cracking, while appearing static during normal use
2Ease of operation
If the mouth-part mounting member engages only with the inner bag, then the operation to pull out the inner bag is simplified, but the inner bag may lift up unintentionally due to rotation
Solution Approach 1:
The engagement mechanism is extended from purely axial engagement to include circumferential engagement through the protruding ridge and groove interface. This adds a rotational constraint dimension while maintaining the simplicity of pulling the inner bag straight out axially
3Adaptability or versatility
If separate inner and outer preforms are stacked for biaxial stretch blow molding, then the manufacturing flexibility is improved, but the process becomes less efficient and requires more space
Solution Approach 1:
The inner preform and outer preform are combined into a single integrated preform structure with the outer preform forming a cavity that contains the inner preform. This merged structure is molded as one piece and then separated during the blow molding process, maintaining flexibility while improving efficiency and reducing space requirements
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 design suppresses cracking in contact projections and prevents unintentional rotation of inner bags, while enabling efficient and space-saving manufacturing of double containers.
Implementation Method 1
a heating device (35), the blow molding device (36) is configured to manufacture a container body by biaxially stretch blow molding the heated preform
Data Source
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AI summary
An object of the present invention is to provide a double container in which, even when a container body is formed by biaxially stretch blow molding a preform configured by covering an inner preform formed by direct blow molding with an outer preform, cracking of a contact projection in a low-temperature drop test is suppressed. According to the present invention, there is provided a double container comprising a container body, wherein the container body comprises an inner bag and an outer shell arranged to cover the inner bag, the inner bag comprises a protruding part that protrudes from an opening end of the outer shell, the protruding part is provided with a protruding cylinder and a contact projection, the contact projection is a portion arranged at a position to contact on the opening end and protruding radially outward from the protruding cylinder, the contact projection has an upper wall and a lower wall extending radially outward from the protruding part, the upper wall is arranged closer to an opening end of the inner bag than the lower wall, and a reinforcing part for suppressing rotation of the upper wall with respect to the lower wall is provided.