Inner Cap Attachment Structure With Alignment Guiding Projection
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Solution Overview
Problem
The existing inner cap attachment-detachment structure for containers faces challenges with uncertain operations due to clearance issues and shape changes between the inner and outer caps, leading to difficulties in smooth engagement and detachment, especially when manufacturing costs are considered, resulting in unreliable plugging and pressing actions.
Innovation Solution
The proposed structure includes an alignment guiding structure with a specific projection width variation and a receiving notch chamfer in the engagement recessed groove, along with opposite engagement projections and a raised surface on the engagement projection, to ensure a stable and accurate engagement between the inner and outer caps, simplifying mold structure and improving injection molding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner cap is tightly embedded in the aperture part in a plug-like state, then the sealability is improved, but the operation of removal and embedment becomes extremely hard to conduct
Solution Approach 1:
The outer cap serves as an intermediary tool that enables the removal and embedment of the inner cap without direct hand contact. The outer cap is equipped with an attachment-detachment operation part that engages with the inner cap's engagement projection, allowing the user to manipulate the inner cap through the outer cap rather than directly handling it.
Solution Approach 2:
The cap system is divided into two functional segments: the inner cap that provides the sealing function by being tightly embedded in the aperture part, and the outer cap that provides the manipulation function with its attachment-detachment operation part. This segmentation allows each component to specialize in its primary function while working together as a system.
2Reliability
If the inner cap is made of soft resin to improve sealability, then the sealing performance is enhanced, but the shape changes between plugging action state and free state cause uncertain operation
Solution Approach 1:
The alignment guiding structure is designed to pre-establish the correct angular relationship between the inner cap and outer cap during the engagement process. The engagement projection's specific shape with varying projection width guides the attachment-detachment operation part into proper alignment before the final bayonet engagement occurs, compensating for the inner cap's shape changes.
Solution Approach 2:
The engagement projection is designed with a specific geometric parameter variation - the projection width changes along its length, being narrower at one end and wider at the other. This parameter change creates an inherent alignment mechanism that guides the engagement process and maintains dimensional stability despite the soft resin material's shape changes.
3Ease of manufacture
If a pair of opposite engagement projections are used to reduce mold cost, then the manufacturing cost is reduced, but clearance issues cause uncertain operation and rattling
Solution Approach 1:
While maintaining the simple pair of opposite engagement projections for cost-effective manufacturing, the engagement projection is designed with asymmetric features - specifically, an alignment guiding structure with varying projection width. This asymmetric design within the symmetric overall structure provides the necessary alignment and stability to prevent rattling and uncertain operation.
Solution Approach 2:
The engagement projection serves multiple functions simultaneously: it provides the bayonet engagement mechanism for attachment and detachment, maintains the correct angular relationship through its varying width profile, and guides the alignment between inner and outer caps. This multi-functionality achieves operation stability without requiring additional components that would increase mold cost.
4Reliability
If the attachment-detachment operation part is embedded in the recessed part of the inner cap, then the engagement state is achieved, but clearance causes the inner cap to cannot be removed or embedded back smoothly
Solution Approach 1:
The alignment guiding structure acts as a preliminary cushioning mechanism that prepares the engagement projection and attachment-detachment operation part for proper engagement. By guiding the alignment before the final engagement occurs, it prevents misalignment and ensures smooth operation during both removal and embedment, compensating for clearance issues.
Data Source
Figure 1(a)~1(e-2)
Figure 2(a)-1~2(d)
Figure 3(a)~3(c)
AI summary
[Problem] To further improve an inner cap attachment-detachment structure previously created by the present inventor, and provide a structure with which it is possible to eliminate uncertain operation even while considering and pursing realistic manufacturing costs. [Solution] The present invention is an inner cap attachment-detachment structure in which a container 1 is capped by a plug-like inner cap 3 and an outer cap 2 mounted to the inner cap 3 so as to be externally overlaid thereupon, and the outer cap 2 is used as a hand tool to attach/detach the inner cap 3 to/from the container 1 in the manner of a bayonet engagement. In particular, said structure is characterized in that: the inner cap 3 is equipped with a recessed part 33 for receiving an attachment-detachment operation part 23 of the outer cap 2; an engagement projection 35 is formed in a plurality in the upper area of the recessed part, and projects toward the inner side of the recessed part; a pressing surface 255 of the attachment-detachment operation part 23 is formed so as to press a plug body 31 of the inner cap 3 from above while in a state of the engagement with the inner cap 3; or the engagement projection 35 is formed such that the upper position of a projection tip end 351 is higher than the height of the upper end of the plug body 31 in a vertical cross-section view.