Pipette Ejector Adjustment and Locking Mechanism
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Solution Overview
Problem
Conventional pipettes lack an effective mechanism to adjust and lock the ejector rod's extended position, leading to inadvertent changes after desired adjustments are made, and there is a need for an infinitely adjustable ejection mechanism with audible and vibrational feedback and a stop to limit adjustment.
Innovation Solution
A pipette design featuring an ejector member with a link member and adjustment device that allows for infinitely adjustable positioning, coupled with a lock device to prevent unintended adjustments, and a bayonet joint for quick connection and disconnection, providing audible and vibrational feedback upon locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an adjustment device is provided to adjust the extended position of the ejector rod, then the adaptability to different pipette and tip sizes is improved, but the reliability to prevent inadvertent adjustment deteriorates
Solution Approach 1:
The ejector rod is made dynamically adjustable through a threaded engagement mechanism between the adjustment device and the ejector rod. The adjustment device can be rotated to extend or retract the ejector rod to different positions, allowing the system to adapt to various pipette and tip configurations rather than being fixed in a single position.
Solution Approach 2:
A lock device with an indicator mechanism provides visual feedback to confirm when the ejector rod has reached the desired extended position. The indicator moves to a predetermined position that is visible to the user, confirming proper adjustment and preventing inadvertent changes by making the current position clearly identifiable.
2Adaptability or versatility
If the ejector rod is made infinitely adjustable, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The lock device is integrated with the adjustment device as a combined unit. The lock device includes a lock member that engages with the adjustment device to prevent rotation, and both functions (adjustment and locking) are performed through a single integrated mechanism rather than separate independent systems, reducing overall complexity.
Solution Approach 2:
The actuator member serves multiple functions: it acts as both the lock device (when in the first rotational position to prevent adjustment) and the ejection mechanism (when in the second rotational position to eject the tip). This multi-functionality reduces the number of separate components needed in the system.
3Reliability
If a lock device is added to prevent inadvertent adjustment, then the reliability is improved, but the ease of operation deteriorates
Solution Approach 1:
The locking and adjusting functions are merged into a single operational sequence. The user performs both adjustment and locking actions by rotating the adjustment device, which simultaneously moves the ejector rod to the desired position and engages the lock mechanism, eliminating the need for separate locking steps.
Solution Approach 2:
The indicator mechanism provides immediate visual feedback during the adjustment process, allowing the user to see when the optimal position is reached and when the lock is properly engaged. This feedback reduces the time and complexity of operation by eliminating the need for trial-and-error adjustment or separate verification steps.
Data Source
Figure 1~2
Figure 3
Figure 4~7
AI summary
A pipette (110) includes an ejector member (140) with an ejector end (142) configured to be moved from the retracted position (147a) to the extended position (147b) to eject a gripped pipette tip (120) from an end portion (132) of the body (130) of the pipette (110). The pipette (110) further includes an adjustment device (160) configured to adjust the extended position (147b) of the ejector end (142) with respect to the body (130) and a lock device (200) configured to selectively inhibit operation of the adjustment device (160) to adjust the extended position (147b) of the ejector end (142).