Medical Actuator Locking Rack for Stable Lever Positioning
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Solution Overview
Problem
Medical device actuators, such as elevator levers in duodenoscopes, often require significant operator force to maintain a desired position, leading to user fatigue and a need for locking mechanisms to prevent unintended movement.
Innovation Solution
The implementation of a locking mechanism using a movable lock and a stationary rack gear with teeth and gaps, allowing the actuator to be locked in a desired position by moving a feature radially inward to clear the teeth, enabling the actuator to be retained without constant operator effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is implemented to prevent unintended movement of the actuator, then reliability is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is self-actuating through spring biasing. The spring automatically pushes the lock feature between the teeth to engage or disengage based on actuator position, eliminating the need for additional actuators or complex control systems. This achieves reliable automatic locking while maintaining simple device structure.
Solution Approach 2:
The lock feature acts as an intermediary element between the actuator and the rack teeth. It mediates the locking function by engaging with the teeth to prevent unintended movement, while the spring mediates the automatic engagement/disengagement action. This intermediary approach simplifies the overall system compared to direct actuation mechanisms.
2Ease of operation
If the actuator is designed to be easily movable for operation, then ease of operation is improved, but reliability deteriorates due to unintended movement
Solution Approach 1:
The locking mechanism transitions between two dynamic states: locked and unlocked. The spring-biased lock feature automatically transitions between these states based on actuator position. During normal operation, the actuator is freely movable; when positioning is complete, the lock automatically engages to maintain position. This dynamic behavior resolves the contradiction between ease of operation and position maintenance.
Solution Approach 2:
The spring continuously applies a preliminary locking force, pushing the lock feature toward the teeth. This preliminary anti-action prevents unintended movement before it can occur. The operator must deliberately overcome this spring force to move the actuator, ensuring reliable position maintenance while allowing intentional movement when needed.
Data Source
AI summary
A handle of a medical device may comprise an actuator; a lock movable relative to the actuator and having a feature movable relative to the actuator; and a rack having plurality of teeth separated from one another by a plurality of gaps. The lock may be configured to move the feature from (a) a first configuration, in which the feature is disposed in the gap, between two of the plurality of teeth, such that the two teeth inhibit the actuator from rotating; to (b) a second configuration, in which the feature is disposed outside of the gap, such that the actuator is rotatable. In the second configuration, the teeth may be disposed between the feature and the actuator.