Coaxial Cap Mechanism for Child-Resistant Liquid Dispensing
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Solution Overview
Problem
Existing liquid dispensing devices lack effective safety mechanisms to prevent accidental opening by children, which can lead to unintended access to the liquid contents and potential intoxication.
Innovation Solution
A liquid dispensing nozzle with a removable cap featuring a coaxial outer and inner casing that moves axially between storage, unscrewing, and safety configurations, requiring a predetermined force to unscrew, ensuring the cap remains secure against child access while allowing adult operation and evaporation of residual liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cap opens by simply unscrewing, then the liquid product becomes easily accessible, but children can open the cap and access the liquid product causing intoxication
Solution Approach 1:
The cap is divided into two separate casings (inner casing and outer casing) that can move relative to each other. The inner casing remains fixed to the dispensing device while the outer casing can be removed. This segmentation allows the cap to provide both easy access (by removing only the outer casing) and safety (by keeping the inner casing sealed to the device).
Solution Approach 2:
The outer casing acts as an intermediary element between the user and the liquid product. It provides a removable barrier that adults can easily remove while preventing children from accessing the liquid. The outer casing mediates between the need for easy access and the need for safety by being removable yet requiring sufficient force to detach.
2Reliability
If the sealing surfaces remain in hermetic contact, then liquid evaporation is prevented during storage, but residual liquid stagnates at the dispensing opening promoting bacterial growth
Solution Approach 1:
The sealing arrangement is made dynamic rather than static. The outer casing can move axially relative to the inner casing between a closed position (where sealing surfaces are in contact) and an open position (where sealing surfaces are separated). This dynamic sealing system allows the cap to prevent evaporation during storage while enabling air circulation to prevent bacterial growth when open.
Solution Approach 2:
The sealing function is discarded when the outer casing is removed for use, allowing air circulation to prevent bacterial growth. The sealing function is recovered when the outer casing is replaced, restoring evaporation prevention for storage. This cyclical discarding and recovering of the sealing function addresses both requirements.
3Object-affected harmful factors
If a predetermined force is required to unscrew the cap, then child access is prevented, but the operation becomes more difficult for adults
Solution Approach 1:
By segmenting the cap into outer and inner casings, the force requirement is applied only to remove the outer casing, not the entire cap assembly. This segmentation reduces the operational difficulty for adults while maintaining the safety function of preventing child access to the liquid product.
Solution Approach 2:
The safety function is extracted from the complete cap removal action and applied specifically to the outer casing removal. The outer casing is designed to require predetermined force to detach, while the inner casing remains easily accessible once the outer casing is removed. This extraction allows safety to be maintained without making the overall operation difficult.
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 enhances safety by preventing unscrewing with insufficient force, reducing the risk of child access while allowing easy adult operation and minimizing liquid stagnation through controlled evaporation, thus preventing bacterial growth.
Implementation Method 1
a rotation in a first direction of the outer casing causes by friction a rotation of the inner casing in the same first direction so as to be able to unscrew the cap
Implementation Method 2
the safety configuration further corresponding to a configuration in which the respective sealing surfaces of the outer casing and the inner casing are separated from each other so as to let air pass between them
Data Source
Figure 1~4
Figure 5A~7B
Figure 8A~9
AI summary
The invention concerns a liquid dispensing nozzle (10) comprising: - a liquid dispensing opening (22), - a removable cap (16) intended to cover the opening (22) when it is mounted on the nozzle (10), the cap (16) comprising an outer casing (42) and an inner casing (44) that are coaxial, mounted so as to be able to move relative to each other in an axial direction (A) of the nozzle (10) between: - a configuration prior to first use, referred to as the storage configuration; - an unscrewing configuration of the cap (16); - a safety configuration when a pressing force applied to the cap (16) is weaker than the predetermined threshold or when no force is applied to the cap (16). The invention also concerns a liquid dispensing device (100) comprising such a nozzle (10) mounted on a container (12).