Fluid Dispenser Locking Member Prevents Valve Stem Movement
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Solution Overview
Problem
Conventional fluid dispensers face challenges in replacing the tappet on the valve stem without inadvertently dispensing fluid, particularly in refillable or 'nomadic' dispensers, where the tappet needs to be removed and reattached without causing fluid to be pushed back through the valve stem.
Innovation Solution
A locking member with a support element is integrated around the valve stem, featuring a radial flange and abutments that allow the tappet to be mounted without moving the valve stem, preventing axial and rotational movement until the tappet is securely reattached, thus preventing fluid dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the tappet is removed and reattached to the valve stem in a conventional dispenser, then the valve stem can be accessed for refilling, but fluid is forced back through the valve stem and plunger making reinstallation impossible without fluid dispensing
Solution Approach 1:
The locking member is activated before the tappet is reinstalled onto the valve stem. By engaging the locking member in the removed position, the valve stem is prevented from moving during tappet installation, allowing the tappet to be safely attached without forcing fluid through the system.
Solution Approach 2:
The locking member acts as an intermediary mechanism between the tappet installation process and the valve stem. It mediates the interaction by providing a mechanical lock that decouples the tappet installation action from the valve stem movement, allowing one without causing the other.
2Ease of operation
If the valve stem is allowed to rotate freely, then the plunger can be oriented as desired, but the tappet cannot be securely reattached without causing fluid dispensing
Solution Approach 1:
The locking member provides dynamic control of the valve stem, allowing it to be free during normal operation for plunger orientation, but becoming fixed when the locking member is engaged during tappet reinstallation. This dynamic switching between free and locked states resolves the contradiction.
Solution Approach 2:
The locking member applies a preliminary restraining action to the valve stem before the tappet is fully installed. This pre-locking prevents the harmful fluid dispensing action that would otherwise occur during tappet reinstallation, while not interfering with plunger orientation during normal use.
3Reliability
If a locking mechanism is added to prevent valve stem movement, then tappet can be reattached without fluid dispensing, but the device complexity increases
Solution Approach 1:
The locking member is designed to be manually operated by the user during tappet reinstallation. It serves itself by using the user's existing action of installing the tappet to trigger the locking mechanism, rather than requiring a separate complex automated locking system.
Solution Approach 2:
The locking mechanism is segmented into simple, discrete components: the locking member with its engagement surfaces and the valve stem with its corresponding features. This segmentation allows the complex function of preventing fluid dispensing to be achieved through simple, modular parts rather than a monolithic complex mechanism.
Data Source
Figure 1a~2b
Figure 3a~4
Figure 5a~5b
AI summary
A device for applying a fluid product (P), comprising a fixed mounting part (1) having a dip tube (10) intended to extend into a container (R) and a fluid product applicator (A) removably mounted on the fixed mounting part (1), the fluid product applicator (A) comprising a sleeve (2) defining internally a collection chamber (C) for collecting fluid product (P) drawn through the dip tube (10), wherein the sleeve (2) has a cylindrical inner wall (21) and the fixed mounting part (1) has a tubing (17) that extends in line with the dip tube (10) and forms a piston lip (19) suitable for coming into a sealed sliding contact with the cylindrical inner wall (2i) of the sleeve (2), the device being characterised in that the locking member (1) has a bushing (12) fixedly engaged about the valve stem (T).