Centrifuge Quick-Action Closure for Axial Rotor Locking
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Solution Overview
Problem
Existing centrifuges with detachable rotors face challenges in providing a reliable and space-efficient axial locking mechanism that maintains rotor security at high speeds and withstands component deformation, often requiring complex designs that weaken the drive shaft.
Innovation Solution
A quick-action closure system with a widened drive shaft portion and blocking elements, activated by a handle, ensures secure axial locking of the rotor to the drive shaft, utilizing a force-transmitting element and spring-loaded blocking elements for reliable retention without lateral forces or significant drive shaft weakening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-loaded bolt engages a recess in the drive shaft to lock the rotor, then axial locking is achieved, but a substantial portion of the drive shaft must penetrate the rotor and the drive shaft is weakened
Solution Approach 1:
Instead of having the locking mechanism in the drive shaft engage the rotor (conventional approach), the invention inverts the arrangement by placing the locking mechanism in the rotor to engage the drive shaft. The locking lever with the engagement surface interacts with the annular groove in the drive shaft, reversing which component contains the locking mechanism and which receives it, thereby avoiding weakening the drive shaft.
Solution Approach 2:
The locking mechanism is segmented into distinct functional elements: the locking lever pivoting about an axis, the engagement surface on the lever, and the annular groove in the drive shaft. This segmentation allows the locking function to be distributed between the rotor and drive shaft without requiring extensive penetration or weakening of either component.
2Reliability
If locking levers pivot about axes perpendicular to the rotation axis to engage an annular groove, then locking is achieved, but at low speeds (approx. 600 rpm) the centrifugal force is insufficient to maintain locking against resonance
Solution Approach 1:
The invention introduces a counterweight element that balances the locking lever system. This counterweight compensates for the insufficient centrifugal force at low speeds by providing an opposing moment that helps maintain the locking engagement. The counterweight acts as a balancing mass that offsets the gravitational and vibrational forces during resonance conditions, enabling reliable locking across a wider speed range including the problematic 600 rpm resonance zone.
3Reliability
If a locking mechanism exerts lateral force on the drive shaft, then locking is achieved, but a certain length portion of the drive shaft is required and space is increased
Solution Approach 1:
The invention inverts the locking arrangement so that the rotor's locking mechanism engages the drive shaft's annular groove rather than the drive shaft's mechanism engaging the rotor. This inversion allows the locking force to be applied axially through the groove engagement rather than laterally, reducing the space requirement and eliminating the need for a lengthy drive shaft portion.
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 provides a reliable, space-efficient, and fail-safe axial locking mechanism that maintains rotor security at high speeds and during component deformation, reducing the risk of imbalance and enhancing durability by minimizing the drive shaft's weakening.
Implementation Method 1
at least one blocking element which—when activated—fixes the rotor relative to the drive shaft
Implementation Method 2
Depending on the speed of rotation, the locking levers can be automatically moved from the unlocking position into the locking position. At approx. 600 rpm, laboratory centrifuges frequently pass through their first resonance.
Data Source
AI summary
A centrifuge (10), having a drive shaft (12), a rotor (40) mounted on the drive shaft (12) so as to be detachable axially in a removal direction (66), a quick-action closure (54) integrated in the rotor (40) and the drive shaft (12), which closure can be used to secure the rotor (40) relative to the drive shaft (12) in a removal direction (66), an abutment (50, 52) in the drive shaft (12) which is engaged by a locking member (46) of the rotor (40), at least one blocking element (76), which—when activated—fixes the rotor (40) relative to the drive shaft (12) and which acts between the locking member (46) of the rotor (40) and the abutment (50, 52) of the drive shaft (12), which quick-action closure (54) includes a force-transmitting element (58, 72). The blocking element (76) is actively connected to an actuating element (100, 100a) via the force-transmitting element (58, 72), that unlocking the quick-action closure (54) is effected by moving the actuating element (100, 100a), the force-transmitting element (58, 72) and the blocking element (76) relative to the locking member (46) in a direction in parallel to the drive shaft (12), and that during unlocking, the actuating element (100, 100a) is moved toward the drive shaft (12), and during locking, the force-transmitting element (58, 72) and the blocking element (76) on the one side and the locking member (46) on the other side are relatively moved toward each other.