Peristaltic Blood Pump Rotor Locking for Keyless Shaft Attachment
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Solution Overview
Problem
The attachment of the rotor to a non-rotationally symmetric drive shaft in peristaltic blood pumps is challenging and requires skill and patience, especially under time pressure in medical settings.
Innovation Solution
A rotationally symmetric drive shaft with a conical or frustoconical sliding section and a locking element design that allows for keyless attachment and secure retention of the rotor, enabling easy alignment and preventing inadvertent release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-rotationally symmetric drive shaft is used with a positive fit mechanism, then the rotor can be securely attached and removed, but the attachment process requires skill and patience and is challenging for operators under time pressure
Solution Approach 1:
The drive shaft is designed with a non-rotationally symmetric profile featuring a flat section that must align with a corresponding flat section on the rotor during attachment. This asymmetric geometry ensures proper orientation and secure attachment while simplifying the alignment process for operators, as the flat sections provide a natural guide for correct positioning without requiring complex alignment procedures
Solution Approach 2:
A flat alignment section is introduced as an intermediary geometric feature between the drive shaft and rotor. This flat section acts as a mediator that guides the rotor into the correct rotational position during attachment, eliminating the need for operators to manually align complex non-rotationally symmetric features and significantly reducing the skill and patience required for the attachment process
2Ease of operation
If a rotationally symmetric drive shaft is used to simplify attachment, then alignment is easier, but the locking element requires additional design features to prevent inadvertent release
Solution Approach 1:
While the overall drive shaft is rotationally symmetric for ease of attachment, the locking element incorporates an asymmetric flat section that engages with a corresponding flat section on the rotor. This asymmetric feature within the locking mechanism prevents inadvertent release by requiring a specific rotational orientation to disengage, thus adding security without compromising the rotational symmetry that simplifies initial attachment
Solution Approach 2:
The locking element is designed as a separate, movable component that can be independently actuated from the main drive shaft body. This segmentation allows the locking function to be controlled separately through a switch mechanism, enabling operators to secure or release the rotor intentionally while preventing accidental release. The flat section on the locking element provides mechanical engagement that maintains security during operation
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
Facilitates simplified and secure attachment of the rotor without requiring precise alignment, reducing the risk of accidental detachment during operation.
Implementation Method 1
A conical or frustoconical sliding section formed by a chamfer is arranged on the head. Thus, the mounting force of the rotor is small.
Implementation Method 2
a locking element is provided for axial securing
Implementation Method 3
the rollers press the tube locally radially outward and, in doing so, by the elastic material properties of the tube generate a blood transport through the tube
Implementation Method 4
The switch is positioned so that it can be pressed down at the same time as the operator of the blood pump and the dialysis machine, resp., grips the rotor
Data Source
AI summary
A rotation unit includes a drive shaft and rotor of a peristaltic pump. The drive shaft attaches a rotor of the blood pump, extends along a central axis, and has a head delimited by a groove. A sliding section is arranged on the head. The rotation unit includes the drive shaft and the rotor with tube rollers which is attachable to the drive shaft. The groove has a flank arranged perpendicularly to the central axis. A locking element is movable transversely to the central axis. An abutment section is biased in the direction of the central axis and in the direction of the groove bottom by a spring arranged in the rotor. The abutment section is movable away from the central axis and groove bottom by an actuating section mounted on or formed integrally with the locking element. An abutment surface is arranged perpendicularly to the central axis.