Hold-Open Latch Cam Geometry for Intuitive Fluid Dispensing
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Solution Overview
Problem
Existing hold-open latches for fluid dispensing devices are often not intuitive, robust, or easy to manufacture, making them challenging to operate effectively.
Innovation Solution
A nozzle system with a latch assembly that includes a cam and engagement surface, allowing the lever to be automatically retained in the operating position by engaging the cam when moved from the non-operating to the operating position, providing tactile feedback and easy operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If existing hold-open latch designs are used, then the lever can be retained in the operating position, but the operation is not intuitive and user effort is excessive
Solution Approach 1:
The cam surface is designed with a curved profile that guides the lever through a natural arcuate motion path. This curvature allows the lever to follow an intuitive circular trajectory during engagement, reducing the cognitive load on the user and making the operation more natural and easier to perform.
Solution Approach 2:
The latch mechanism transitions from a static holding position to a dynamic engagement process. The cam and lever work together to create a controlled motion sequence where the lever naturally follows the cam surface during engagement, providing dynamic feedback that guides the user through the correct operating sequence without requiring complex manual manipulation.
2Ease of operation
If existing hold-open latch designs are used, then the lever can be retained in the operating position, but the operation lacks tactile feedback
Solution Approach 1:
The cam surface is designed to provide progressive tactile feedback during lever engagement. As the lever moves along the cam surface, the user experiences distinct tactile cues including initial contact, engagement resistance, and final locking position. This feedback mechanism confirms proper operation through touch, enhancing both user confidence and operational reliability without requiring visual confirmation or complex mechanisms.
3Reliability
If a robust latch mechanism is implemented, then the lever retention is secure, but the manufacturing complexity increases
Solution Approach 1:
The cam and latch body are designed as integrated components that can be manufactured as single pieces using conventional machining or molding processes. The cam surface is directly formed on the latch body, eliminating the need for separate cam components, complex assemblies, or specialized manufacturing processes. This integration maintains robust lever retention while significantly simplifying manufacturing and reducing part count.
4Reliability
If the cam pivots about an axis aligned with the lever plane, then the mechanism is simpler, but the lever cannot be properly retained in the operating position
Solution Approach 1:
The cam is configured with an asymmetric geometry where the pivot axis is deliberately positioned perpendicular to the lever plane rather than aligned with it. This asymmetric arrangement creates the necessary mechanical advantage and engagement geometry for reliable lever retention. The offset pivot position generates the correct force vectors during engagement, ensuring secure holding while maintaining reasonable structural simplicity.
Data Source
AI summary
A nozzle system including a nozzle body configured to dispense fluid therethrough and a lever coupled to the nozzle body and movable in a lever plane between a non-operating position and an operating position. The nozzle system further includes a latch assembly having an engagement surface and a cam. The cam is coupled to or positioned on one of the nozzle body or the lever, and the engagement surface is coupled to or positioned on the other one of the nozzle body or the lever. The nozzle system is configured such that when the lever is moved from the non-operating position to the operating position, the engagement surface engages the cam to cause at least one of the engagement surface or the cam to move relative to the other such that the lever is automatically retainable in the operating position by the latch assembly. The cam does not pivot about an axis aligned with the lever plane when the lever is moved from one of the non-operating position or the operating position to the other one of the non-operating position or the operating position.