Pipette Single-Actuator Ejection Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pipettes require two buttons for operation, leading to increased expense and complexity in producing different sizes, and often result in larger dead volumes that affect dosing accuracy.
Innovation Solution
A pipette design with a detachable connection between the displacement unit and drive unit, allowing for a single actuating element to control both dosing and ejection, reducing the stress on components and enabling easier assembly and disassembly, while minimizing dead volume through a decoupling device that limits the downward movement of the drive element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a separate ejection device with its own drive mechanism is used, then pipette tip ejection is achieved, but the device complexity and number of components increase
Solution Approach 1:
The patent combines the ejection function with the existing dosing piston mechanism. The piston's rod is extended to directly contact and push the pipette tip during the ejection stroke, merging the dosing and ejection functions into a single mechanism that operates with one button press.
Solution Approach 2:
The piston mechanism serves multiple functions: it performs the dosing stroke to aspirate and dispense liquid, and then performs an ejection stroke to remove the pipette tip. This multi-functionality eliminates the need for a separate ejection device and reduces the number of operational steps.
2Ease of operation
If the piston is allowed to move freely after the dosing stroke, then the ejection stroke can be performed, but a dead volume is created that affects dosing accuracy
Solution Approach 1:
The piston rod is pre-positioned to extend beyond the piston during the dosing stroke, so that when the ejection stroke begins, the rod is already in position to immediately contact and eject the pipette tip without requiring the piston to travel through a dead volume.
Solution Approach 2:
The extended piston rod acts as an intermediary element that transfers the ejection force directly to the pipette tip. This intermediary allows the ejection function to be performed without the piston itself needing to occupy or create a dead volume in the cylinder.
3Adaptability or versatility
If different sized displacement units are produced for different pipette sizes, then various dosing ranges are achieved, but the production cost and complexity increase
Solution Approach 1:
The pipette is divided into modular components: a standardized drive unit with the actuating mechanism and a variable displacement unit that can be exchanged. This segmentation allows the expensive, complex drive unit to be produced once and reused, while only the simpler displacement units need to be varied for different dosing ranges.
Solution Approach 2:
The drive unit is designed with universal features that allow it to work with multiple displacement units of different sizes. The piston rod extension and ejection mechanism are configured to accommodate various piston diameters and stroke lengths, enabling a single drive unit design to serve multiple dosing ranges.
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 pipette achieves one-button operation, reduces construction and production costs, and minimizes dosing errors by eliminating the need for separate ejection and dosing mechanisms, allowing for use with various displacement units to create pipettes of different sizes.
Implementation Method 1
The decoupling device is formed by a magnet arrangement with a magnet and a magnetizable counterpart, which can be separated from each other after overcoming a retention force
Data Source
AI summary
A pipette with a displacement unit, a drive unit, means for the detachable connection that detachably connects together the upper housing part and the lower housing part, an ejection device, an end stop, a decoupling device and coupled to the drive device, a lower stop body that upon decoupling of the drive element from the drive device by the decoupling device strikes the actuating end of the ejection extension in order, with further shifting of the actuating element in the actuating direction, to shift downward the ejection extension and the ejection slide.