Pipetting Head O-Ring Clamping Mechanism
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Solution Overview
Problem
Existing pipetting devices require high forces and complex designs to securely clamp and eject pipette tips, which can lead to user strain and increased mechanical complexity, and are often limited to specific tip sizes and manual magazine filling.
Innovation Solution
A pipetting head with two elastomer O-rings per attachment that securely clamps pipette tips through O-ring deformation, reducing the need for direct contact with the attachment and allowing for precise alignment and easy transfer of various tip sizes, using a configuration that includes axial position securing apparatuses and a displacement apparatus for liquid handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct contact between attachment and pipette tip is used for clamping, then secure clamping is achieved, but high forces are required and pipette tip deformation occurs
Solution Approach 1:
An elastomeric intermediate element (O-ring) is introduced between the attachment and the pipette tip. The O-ring deforms elastically under compression to securely clamp the pipette tip without requiring high forces that would deform the rigid plastic tip. The intermediate elastomeric material absorbs the clamping force while maintaining a secure connection.
2Adaptability or versatility
If multiple O-rings are used per attachment, then secure handling of various tip sizes is achieved, but device complexity increases
Solution Approach 1:
The system uses O-rings with different cross-sectional dimensions (different parameters) to accommodate various pipette tip sizes. By changing the O-ring cross-section parameters, the attachment can adapt to different tip diameters while maintaining secure clamping. This parameter variation provides versatility without requiring completely different attachment structures for each tip size.
3Ease of operation
If high ejection forces are applied to detach pipette tips, then tip release is achieved, but user strain and mechanical complexity increase
Solution Approach 1:
The elastomeric O-ring serves as an intermediary that facilitates easy tip release. When ejection force is applied, the O-ring deforms and releases its grip on the pipette tip, allowing detachment with minimal force. The elastomeric material's ability to deform and recover enables gentle tip release without requiring high ejection forces that would strain the user or increase mechanical complexity.
4Strength
If rigid attachment structures are used for clamping, then structural strength is maintained, but precision alignment of pipette tips is difficult
Solution Approach 1:
The O-ring cross-sectional parameters are optimized to balance between providing sufficient clamping force and enabling precise alignment. The elastomeric material's dimensional parameters are selected to allow the pipette tip to settle into a precise position while the attachment maintains its structural strength. This parameter optimization achieves both strength and alignment precision.
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 solution reduces the force required for clamping and ejecting pipette tips, simplifies the design, allows for secure handling of different tip sizes, and enables precise alignment, reducing user strain and mechanical complexity while enabling efficient liquid handling and automatic tip transfer.
Implementation Method 1
the inner diameter of a scaling seat of the pipette tip is smaller than the outer diameter of the respective O-ring so that the latter is deformed while being slid on and securely clamps the pipette tip on the attachment
Implementation Method 2
at least one displacement apparatus for air is integrated in the pipetting device and connected via a connecting hole in each attachment to communicate with a pipette tip clamped thereon. By means of the displacement apparatus, an air cushion can be shifted so that liquid is sucked into, and ejected out of, the pipette tip
Data Source
AI summary
A pipetting head comprises a carrier, at least one attachment held on the carrier and configured to secure at least one pipette tip, and two O-rings retained on the at least one attachment and configured to contact the sealing seat of the at least one pipette tip. The inner diameter of the sealing seat of the at least one pipette tip is smaller than an outer diameter of a respective O-ring where the sealing seat contacts a respective O-ring. The respective O-ring is deformed while the pipette tip is slid onto the at least one attachment to securely clamp the at least one pipette tip. The sealing seat of the at least one pipette tip is dimensioned such that the at least one attachment exerts a force on the pipette tip to deform the at least one pipette tip when it is securely clamped on the at least one attachment.