Pipette Locking Sleeve for Low-Force Tip Release
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Solution Overview
Problem
Existing pipettes with integrated plunger tips face challenges such as high force requirements for connecting and releasing the tip, potential for unintentional release of the plunger, and increased risk of contamination during bayonet lock operation.
Innovation Solution
A pipette design featuring a rod-shaped housing with a neck for holding a pipette tip and a stroke rod for displacing the tip plunger, utilizing a locking sleeve that secures the tip plunger to the stroke rod and allows for easy release with minimal force, thereby preventing accidental detachment during use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a bayonet lock mechanism is used to connect the pipette tip to the pipette, then the connection is secure, but high force is required for connecting and releasing the tip
Solution Approach 1:
The connection mechanism is divided into two independent segments: a locking sleeve that secures the tip plunger to the stroke rod, and a separate release mechanism. This segmentation allows the locking function to be maintained while reducing the force needed for release, as the locking sleeve can engage multiple positioning sites along the stroke rod rather than requiring a single high-force bayonet lock engagement.
2Reliability
If a bayonet lock mechanism is used to secure the tip plunger, then the connection is reliable, but unintentional release may occur during operation
Solution Approach 1:
The locking sleeve is designed with multiple localized positioning sites (first, second, and third positioning sites) along the stroke rod, each providing a specific locking position. This local quality approach ensures that the tip plunger can be securely locked at multiple discrete positions, preventing unintentional release while allowing intentional repositioning when needed during pipetting operations.
3Manufacturing precision
If the tip plunger is firmly secured to the stroke rod, then liquid handling is precise, but contamination risk increases during release operations
Solution Approach 1:
The tip plunger is extracted from the pipette tip through a controlled release mechanism that involves displacing the locking sleeve to a fourth positioning site and pressing the ejection button. This extraction process is designed to minimize contamination risk by providing a dedicated ejection path and mechanism that separates the tip plunger removal from the main liquid handling pathway, allowing precise dosing to be maintained while reducing contamination hazards during release.
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 design reduces the forces required for connecting and releasing the pipette tip, enhances secure holding of the tip plunger, and minimizes contamination risks, ensuring reliable and efficient operation, especially when handling highly viscous liquids.
Implementation Method 1
the stroke rod can be elastically expanded by means of the upper end of the tip plunger being inserted into the receiving means of the stroke rod or the upper end of the tip plunger can be elastically expanded by means of the lower end of the stroke rod being inserted into a receiving means of the tip plunger
Implementation Method 2
When displacing the stroke rod downward to a lower stop, a spring apparatus is pretensioned. After the operating element is released, the spring apparatus displaces the stroke rod to an upper stop, wherein the tip plunger is entrained and liquid can be aspirated into the pipette tip.
Data Source
AI summary
A pipette comprises a housing extending from a lower end to an upper end and a neck extending from the lower end of the housing and configured to hold a pipette tip. A stroke rod comprising an upper end and a lower end is configured to displace a tip plunger in the pipette tip. A drive apparatus is configured to displace the stroke rod to: (1) aspirate a liquid specimen into the pipette tip held on the neck; and (2) to eject the specimen from the pipette tip by means of a tip plunger positively connected to the stroke rod. At least one locking sleeve is arranged coaxially with the stroke rod and configured to be displaceably guided toward the stroke rod in the housing The locking sleeve is configured to inhibit release of a tip plunger from the stroke rod.