Worm-Drive Surgical Instrument Actuation With Fewer Moving Parts
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Solution Overview
Problem
Conventional surgical instruments with force transmission mechanisms require many moving parts, leading to increased manufacturing costs, maintenance difficulties, and limited usability due to complex designs that include many intermeshed elements, while also lacking efficient conversion of rotational motion to translational motion for actuating surgical instruments.
Innovation Solution
A force transmission mechanism comprising a worm drive and a lever arm, where the lever arm engages the worm drive to convert rotational movement into translational movement of an actuation element, allowing for efficient actuation of surgical instruments with fewer parts and lower manufacturing costs, while maintaining low friction for effective force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional force transmission mechanisms with many moving parts are used, then reliable force transmission is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the worm drive and lever arm into a single integrated force transmission mechanism. The lever arm is directly coupled to the worm drive, eliminating the need for separate followers and reducing the number of moving parts while maintaining reliable force transmission from rotational to translational motion
Solution Approach 2:
The lever arm serves multiple functions: it acts as a follower to convert rotational motion from the worm drive, serves as a structural support, and directly transmits force to the actuation element. This multi-functionality reduces the overall number of components needed in the mechanism
2Reliability
If conventional force transmission mechanisms with many intermeshed elements are used, then force transmission is achieved, but ease of manufacture decreases
Solution Approach 1:
By merging the lever arm and follower into a single component that directly engages the worm drive, the patent eliminates complex intermeshed elements and reduces manufacturing steps. The simplified mechanism requires fewer precision-machined interfaces and assembly operations
Solution Approach 2:
The patent extracts and eliminates unnecessary intermediate components from conventional force transmission mechanisms. By removing redundant followers and intermeshed elements, the design achieves force transmission with fewer parts that are easier to manufacture and assemble
3Ease of operation
If conventional actuation mechanisms are used, then actuation function is achieved, but space efficiency decreases
Solution Approach 1:
The integration of the lever arm with the worm drive creates a compact force transmission mechanism that occupies minimal space within the surgical instrument. The combined structure eliminates the need for separate housings and mounting features for individual components
Solution Approach 2:
The actuation element is positioned to extend through the shaft and couple with the lever arm in a nested arrangement. This allows the force transmission mechanism to be compactly arranged within the instrument shaft, maximizing space efficiency
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
The mechanism efficiently translates rotary motion into linear motion, conserving space and reducing manufacturing complexity, enabling high-torque actuation of surgical instruments with low friction and back-drivability, thus improving the usability and reliability of surgical instruments.
Implementation Method 1
The force transmission mechanism may include a worm drive and a lever arm. The lever arm may include a follower that engages the worm drive and is driven by the worm drive.
Data Source
AI summary
A force transmission mechanism for a surgical instrument includes a worm drive, a lever arm, and an actuation element. The lever arm may include a follower member at a first end of the lever arm. The follower member engages the worm drive and is configured to be driven by the worm drive. The actuation element is connected the lever arm. The actuation element is configured to transmit force to actuate an end effector of the surgical instrument. Rotational movement of the worm drive imparts translational movement to the actuation element via the lever arm.