Pipette Tip Mounting Shaft With Locking Lobes
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Solution Overview
Problem
Existing pipette tip mounting systems require excessive insertion and ejection forces, which can lead to instability and unintentional removal of tips, especially in handheld multi-channel pipettors.
Innovation Solution
The configuration of circumferentially spaced locking lobes on the mounting shaft with inclining and declining ramps, where the peak of each lobe is curved and located at a maximum outward distance from the shaft axis, reduces friction and forces required for tip engagement and ejection, while maintaining stability through a secure over-center locking mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional tapered fit mounting shaft is used to secure pipette tips, then tip stability is improved, but insertion and ejection forces become excessive
Solution Approach 1:
The mounting shaft is segmented into distinct functional zones: a tapered upper section for initial insertion and alignment, and a lower section with locking lobes featuring inclining and declining ramps for secure engagement. This segmentation allows each zone to perform its specific function optimally without requiring excessive force throughout the entire mounting process.
Solution Approach 2:
The locking lobes incorporate variable slope angles - an inclining ramp portion that transitions to a declining ramp portion. This parameter change in the geometric profile allows the mounting shaft to progressively engage the tip collar, reducing insertion force while maintaining stable locking engagement at the final position.
2Stability of the object's composition
If excessive force is applied to jam the tip mounting shaft into the collar, then tip stability is improved, but unintentional removal and instability increase
Solution Approach 1:
The locking lobes with inclining and declining ramps create a dynamic engagement mechanism that transitions from initial contact through progressive engagement to a stable locked position. This dynamic process allows the system to adapt to variations in insertion force while reliably achieving secure engagement without over-compression.
Solution Approach 2:
The mounting shaft design enables self-regulating engagement where the inclining ramps guide the tip collar onto the shaft, and the declining ramps automatically establish the locked position. The system self-adjusts to achieve proper engagement without requiring excessive external force, preventing both instability and unintentional removal.
3Reliability
If traditional sealing rings and tapered fits are used, then sealing is achieved, but manufacturing complexity and precision requirements increase
Solution Approach 1:
The locking lobes with inclining and declining ramps serve multiple functions simultaneously: they guide insertion, provide mechanical locking, and maintain sealing engagement. This multi-functionality eliminates the need for separate complex sealing mechanisms while ensuring reliable sealing through the standardized tip-shaft interface.
Solution Approach 2:
The geometric parameters of the locking lobes, particularly the ramp angles and lobe dimensions, are optimized to provide both sealing and locking functions. By carefully controlling these parameters within specified ranges, the design achieves reliable sealing engagement while simplifying manufacturing compared to traditional multi-component sealing systems.
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 significantly lowers ejection forces while maintaining tip stability, reducing insertion and ejection forces by up to 30% and providing secure, stable mounting without sacrificing lateral stability, as demonstrated by reduced force measurements in various tip sizes.
Implementation Method 1
reduces friction and forces required for tip engagement and ejection
Implementation Method 2
The peak of each lobe is curved and located at a maximum outward distance from the shaft axis
Data Source
AI summary
A pipette tip mounting shaft includes outwardly circumferentially extending locking lobes over which the pipette tip collar is mounted. The locking lobes preferably include an inclining ramp portion that gently flexes and distorts the pipette tip collar out-of-round as the mounting shaft is inserted into the pipette tip, rather than the stretching tip collar. Each locking lobe also includes a declining ramp portion which extends upward along the mounting shaft. The peak of the lobes is preferably curved. When the pipette tip is fully mounted on the mounting shaft, a locking ring on the inside surface of the tip collar engages the declining ramp of the lobes to provide an over-center engagement, however, the required ejection force is small.