Lost-Motion Foam Pump Linkage for Priming and Adjustable Output
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Solution Overview
Problem
Foam pumps often experience issues with air trapped in the liquid piston, leading to inconsistent output and failure to prime when short stroked, and lack the ability to adjust dispensing volume without replacing the pump.
Innovation Solution
The design incorporates a lost motion linkage system with adjustable output, featuring a liquid piston and air piston linked to an actuator, allowing for varying degrees of 'lost motion' and adjustable output configurations through different securing positions and connector mechanisms, ensuring consistent dispensing and flexibility in dosage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blocking plate is added to prevent full stroke movement, then short stroking is prevented, but the pump will not prime because air bubbles remain in the liquid piston
Solution Approach 1:
The patent implements a dynamic lost motion linkage that allows the actuator to move through a greater range than the liquid piston stroke. The linkage includes a pivot point that enables the actuator to return further than the piston travel distance, creating a 'lost motion' zone that ensures complete piston return and priming while still allowing short stroke operations to function properly.
Solution Approach 2:
The lost motion linkage acts as an intermediary mechanism between the actuator and the liquid piston. This intermediate linkage transfers motion from the actuator to the piston while accommodating different stroke lengths, ensuring that even short actuator strokes can still achieve complete piston return for proper priming.
2Reliability
If the pump is designed for full stroke operation, then consistent output is achieved, but the pump cannot be adjusted for different dispensing volumes
Solution Approach 1:
The patent employs a dynamic lost motion linkage system that can be configured in multiple positions. By adjusting the linkage configuration, the effective stroke length of the liquid piston can be changed while maintaining complete return motion. This allows the same pump mechanism to deliver different dispensing volumes while preserving output consistency through full priming cycles.
Solution Approach 2:
The linkage system is segmented into adjustable components that can be positioned at different locations along the actuator stroke. This segmentation allows the pump to be configured for different dispensing volumes by changing the effective stroke length, while each configuration maintains reliable full-stroke operation for consistent output.
3Reliability
If the actuator stroke is made greater than the liquid piston stroke, then lost motion is achieved for better priming, but the device complexity increases
Solution Approach 1:
The lost motion linkage uses a simple pivot-point design that creates the greater actuator stroke dynamically through geometric relationships rather than additional mechanical components. The linkage leverages the natural rotation and translation of the pivot point to extend the actuator travel distance beyond the liquid piston stroke, achieving lost motion with minimal added complexity.
Data Source
AI summary
Embodiments of lost motion foam pumps are disclosed herein. One exemplary embodiment includes a liquid chamber, a liquid piston movable in the liquid chamber, an air chamber and an air piston movable in the air chamber. The air piston is linked to the liquid piston. A connector is linked to the air piston or the liquid piston. The connector includes an engagement member for connecting to an actuator of a foam dispenser. Movement of the actuator in a first direction moves the liquid and air pistons to contract the liquid chamber and the air chamber. Movement of the actuator a first distance in a second direction does not move the liquid piston or the air piston; however, continued movement of the actuator a second distance in the second direction moves the liquid piston and the air piston and expands the liquid and air chambers.