Two-Stage Trigger Lock Mechanism for Child-Resistant Spray Devices
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Solution Overview
Problem
Conventional spray devices for household cleaning products are not effectively child-resistant, as they require users to deliberately return them to a 'safe' condition after use, leading to frequent misuse and accidental exposure, especially among young children.
Innovation Solution
A two-stage trigger lock mechanism that must be engaged in a specific sequence to function, featuring a shroud with inward ribs and a pivotable lever, biased to automatically return to a locked position, making it difficult for children to operate while allowing easy use for adults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional spray device uses a simple trigger mechanism that is easy to operate, then ease of operation is improved, but child-resistance deteriorates because children can easily manipulate the nozzle to the open position
Solution Approach 1:
The trigger mechanism is divided into two separate functional components: a shroud that must be moved to a release position and a trigger that can then be actuated. This segmentation creates a two-stage operation that is difficult for children to accomplish but straightforward for adults who understand the sequence.
Solution Approach 2:
The shroud must be moved to the release position before the trigger can be actuated. This preliminary action of moving the shroud first creates a deliberate sequence that requires cognitive understanding and deliberate intent, preventing accidental activation by children while maintaining ease of use for adults.
2Object-affected harmful factors
If a spray device includes a safety feature that requires the user to return it to a safe condition after use, then child-resistance is improved, but reliability deteriorates because users often forget to return the mechanism to the locked position
Solution Approach 1:
The mechanism automatically returns the shroud to the locked position after the trigger is actuated. The spring-loaded design causes the shroud to self-return to the safe condition without requiring user intervention, ensuring reliable child-resistance while eliminating the burden of manual locking.
Solution Approach 2:
The spring mechanism provides automatic feedback by returning the shroud to the locked position after trigger actuation. This self-correcting feedback loop ensures that the system reliably returns to the safe state without depending on user memory or deliberate action.
3Object-affected harmful factors
If a spray device uses a two-stage trigger lock mechanism with a lever and ribs, then child-resistance is improved by requiring a complex operational sequence, but device complexity increases
Solution Approach 1:
The shroud, lever, ribs, and spring are merged into a single integrated assembly that performs multiple functions. The shroud serves as both a protective cover and a locking component, while the lever integrates the release mechanism. This merging reduces the number of separate parts while maintaining the two-stage safety sequence.
Solution Approach 2:
The shroud serves multiple functions: it protects the trigger mechanism, provides the locking surface for the ribs, and acts as the movable component that enables or disables trigger access. This multi-functionality reduces overall device complexity while maintaining child-resistance through the integrated two-stage design.
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 mechanism restricts children's ability to dispense the contents by requiring a complex operational sequence and sufficient strength, automatically returning to a locked state, thus enhancing child-resistance and reducing accidental poisonings.
Implementation Method 1
A spring is mounted in contact with the shroud for biasing the shroud toward the trigger lock position
Implementation Method 2
A lever is pivotably mounted to the spray device and configured to traverse a path that intersects the ribs to move the shroud from a trigger lock position to a trigger release position
Data Source
AI summary
A fluid container spray device having a trigger lock mechanism with trigger tabs extending outwardly from the trigger and cleats extending inwardly from a moveable shroud. The cleats obstruct the tabs when the shroud is in a trigger lock position. A lever extending from beneath the shroud can be depressed, thereby moving the shroud from the trigger lock position to a trigger release position. The movement of the shroud to the trigger release position moves the connected cleats from their obstructive position to a position out of the trigger tabs' path of movement, thereby permitting use of the trigger to pump fluid from the container. The shroud is biased toward the trigger lock position. Thus, release of the container by the user restores the locked configuration, thereby preventing use by children.