Peristaltic Blood Pump Rotor Locking With Conical Drive-Shaft Guidance
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Solution Overview
Problem
The attachment of the rotor to the drive shaft in peristaltic blood pumps is challenging due to the need for precise rotational alignment and can be cumbersome for clinical staff under time pressure.
Innovation Solution
A rotationally symmetrical drive shaft with a conical sliding section and a frictional coupling, allowing for easy plug-in of the rotor without requiring precise rotational alignment, and a locking mechanism with a spring-loaded actuating section to secure the rotor during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-rotationally symmetrical drive shaft is used with a locking mechanism, then the rotor can be securely locked during operation, but the attachment process requires careful rotational alignment and forced rotation which challenges dexterity and patience
Solution Approach 1:
The drive shaft employs a rotationally symmetrical design with a circumferential groove that allows the rotor to be attached in any rotational position without requiring precise alignment. This symmetry eliminates the forced rotational movement problem while maintaining secure locking through the groove's engagement with the rotor's protrusion.
Solution Approach 2:
The locking mechanism is segmented into a stationary circumferential groove in the drive shaft and a movable locking element in the rotor. The groove provides the locking path while the movable element engages and disengages from the groove, allowing secure locking during operation while permitting easy attachment and removal when needed.
2Reliability
If a movable locking element with positive locking action is used, then the rotor can be securely held during operation, but the switch actuation surface must be accessible which creates conflict when the operator grasps the rotor
Solution Approach 1:
The actuating surface of the switch is arranged at an angle of 45° to the drive shaft axis, creating a diagonal access path that allows simultaneous grasping of the rotor and actuation of the switch. This angular orientation resolves the spatial conflict between rotor grasping and switch actuation by utilizing a different dimensional approach.
Solution Approach 2:
The locking element is designed to be movable rather than fixed, allowing it to be engaged or disengaged from the circumferential groove by actuating the switch. This dynamic design enables the rotor to transition between locked and unlocked states while maintaining secure holding during operation.
3Ease of operation
If a rotationally symmetrical drive shaft with frictional engagement is used, then the rotor can be easily attached without forced rotation, but the locking mechanism requires additional components to prevent accidental removal
Solution Approach 1:
The circumferential groove acts as an intermediary structure that provides both the frictional engagement for easy attachment and the positive locking path for secure holding. The groove's geometry allows the rotor to be easily attached through friction while preventing accidental removal through geometric constraint.
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 easy and secure attachment and detachment of the rotor, reducing the risk of jamming and accidental unlocking, thereby simplifying the process for clinical staff.
Implementation Method 1
A locking element is provided for axial securing... which also has a positive locking action
Implementation Method 2
the torque is transferred from the drive shaft to the rotor via a circumferential frictional engagement on the circular cylindrical contact area
Data Source
Figure 1~2
Figure 3~4
AI summary
A drive shaft (2) for a rotor of a peristaltic pump and a rotational unit comprising such a drive shaft and a rotor (1) are disclosed. The drive shaft (2) is designed and configured for mounting a rotor (1) of the blood pump, the drive shaft (2) extending along a central axis (25) and having a rotationally symmetrical head (3) at a free end section, which is bounded by a groove (24). A conical or frustoconical sliding section (30) formed by a chamfer is arranged on the head (3).The rotary unit has a drive shaft (2) and a rotor (1) with hose rollers (4) attached to or mounted on the rotor, wherein the groove (24) has a top-side groove flank (37) arranged perpendicular to the central axis (25), and wherein a locking element (10) is arranged in the rotor (1) and is movable transversely to the central axis (25), and the contact section (22) of the locking element is biased by a spring (28) in the direction towards the central axis (25) and towards the bottom of the groove. The contact section (22) is movable away from the central axis (25) and away from the bottom of the groove by means of an actuating section (12) attached to or integrally formed with the locking element (10). A contact surface of the contact section (22) is arranged perpendicular to the central axis (25).