Fluid Dispenser Lever Mechanism for Thick-Fluid ADA Actuation
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Solution Overview
Problem
Fluid dispensers face challenges in dispensing products with increased concentration and thickness, requiring more force to actuate the dispensing pump, while also needing to comply with the Americans with Disabilities Act's requirement of no more than 5 pounds of force to activate controls.
Innovation Solution
The dispenser mechanism incorporates a lever member with a fulcrum and an actuator providing varying mechanical advantage through multiple contact points, allowing for increased output force at the beginning of the dispensing motion while reducing the force required, ensuring compliance with ADA standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single contact point between the lever member and actuator is used, then the device complexity is reduced, but the output force is insufficient to dispense thick, concentrated fluids while complying with ADA force limits
Solution Approach 1:
The actuator is divided into multiple contact points (first, second, and third contact points) along its surface, allowing the lever member to interact with different segments during the actuation stroke. This segmentation enables varying mechanical advantage throughout the motion, increasing output force without requiring a completely complex mechanism.
Solution Approach 2:
The mechanical advantage dynamically changes as the lever member moves through its range of motion, transitioning between different contact points on the actuator. The first contact point provides high mechanical advantage at the beginning of the stroke, the second contact point provides intermediate advantage, and the third contact point provides lower advantage toward the end, creating a dynamic force multiplication system.
2Productivity
If the lever member requires high input force to dispense thick fluids, then the dispensing capability is improved, but compliance with ADA standards requiring maximum 5 pounds of force is violated
Solution Approach 1:
The mechanical advantage parameter changes throughout the actuation stroke by transitioning between different contact points. The first contact point provides maximum mechanical advantage for overcoming the high resistance of thick fluids, while subsequent contact points provide progressively lower advantage, allowing the system to dispense viscous products with limited input force while maintaining ADA compliance.
3Force
If a lever member with fixed mechanical advantage is used, then the device complexity is minimized, but it cannot provide sufficient force for thick fluids throughout the entire range of motion
Solution Approach 1:
The actuator surface is segmented into multiple contact points that engage sequentially during the lever member's rotation. This segmentation allows the system to maintain effective force transmission throughout the entire range of motion without requiring complex variable geometry mechanisms, as each segment provides appropriate mechanical advantage for its portion of the stroke.
Solution Approach 2:
The system achieves dynamic mechanical advantage through the sequential engagement of multiple contact points as the lever member rotates. This dynamic interaction between the lever and actuator contact points ensures sufficient output force is maintained throughout the complete range of motion, from initial actuation through final dispensing position.
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
This design provides a smoother user experience by requiring less initial input force and minimizing interference with the dispensing mechanism, effectively addressing the dispensing challenges of thicker fluids while adhering to accessibility regulations.
Implementation Method 1
a lever member having a first lever section accessible on an exterior side of the housing, a second lever section, and a fulcrum connected between the first lever section and the second lever section, the fulcrum pivotally supported within the housing so that the lever member is moveable between a rest position and a dispense position upon application of an input force to the first lever section
Implementation Method 2
an actuator configured to provide at least two contact points with the second lever section as the lever member is moved from the rest position to the dispense position such that the mechanical advantage provided at a first one of the at least two contact points is greater than the mechanical advantage provided at a second one of the at least two contact points
Data Source
AI summary
A fluid dispenser includes a dispense mechanism that provides for increased mechanical advantage. The dispense mechanism includes a lever member and an actuator. The lever member includes a first lever section that receives application of an input force and a second lever section that applies an output force to the actuator. The lever member and/or the actuator are configured to provide at least two contact points between the actuator and the second lever section during the course of a dispensing stroke such that the mechanical advantage provided at a first one of the at least two contact points is greater than the mechanical advantage provided at a second one of the at least two contact points.