Surgical Instrument Worm-Drive Lever Assembly for Low-Friction Actuation
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Solution Overview
Problem
Conventional surgical instruments with force transmission mechanisms require many moving parts, increasing manufacturing costs and complicating maintenance, while also facing challenges in efficiently converting rotational motion to translational motion for actuating surgical end effectors with low friction and high torque.
Innovation Solution
A surgical instrument with a worm drive and lever arm assembly that converts rotational movement into translational movement through a follower member and actuation element, utilizing a worm drive with a threaded section and a lever arm that pivots or slides to efficiently transmit force with low friction, allowing for both roll and translational movement of the actuation element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional force transmission mechanisms are used, then reliable force transmission is achieved, but the number of moving parts increases, increasing manufacturing costs and complicating maintenance
Solution Approach 1:
The patent combines the worm drive and lever arm into a single integrated assembly where the lever arm is directly coupled to the worm drive output. This merging eliminates the need for separate coupling mechanisms, reducing the total number of moving parts while maintaining reliable force transmission from the rotational worm drive to the translational actuation element.
Solution Approach 2:
The lever arm serves multiple functions simultaneously: it acts as a structural support, a motion conversion element (transforming rotational motion to translational motion), and a force transmission component. This multi-functionality reduces the need for additional dedicated components, thereby reducing device complexity while maintaining reliability.
2Force
If conventional force transmission mechanisms are used, then force transmission is achieved, but manufacturing costs increase due to many moving parts
Solution Approach 1:
By merging the worm drive and lever arm into an integrated assembly, the patent reduces the total component count that requires manufacturing, assembly, and quality control. This directly lowers manufacturing costs while the worm drive mechanism itself maintains effective force transmission capability through its inherent mechanical advantage.
Solution Approach 2:
The patent extracts and eliminates unnecessary intermediate components from conventional force transmission mechanisms, retaining only the essential worm drive and lever arm assembly. This simplification reduces manufacturing complexity and cost while preserving the core force transmission function.
3Power
If conventional force transmission mechanisms are used, then actuation is achieved, but friction increases and torque efficiency decreases
Solution Approach 1:
The lever arm acts as an intermediary element between the worm drive and the actuation element, providing a mechanical advantage that amplifies the torque from the worm drive while minimizing energy loss through friction. The lever arm's pivot point serves as an efficient force multiplication mechanism.
Solution Approach 2:
The worm drive utilizes a helical screw geometry that provides continuous contact between the worm and lever arm, distributing friction forces along the curved contact surface. This curved contact geometry reduces peak friction losses compared to point or line contact mechanisms.
4Manufacturing precision
If complex force transmission mechanisms are used, then actuation precision is achieved, but maintenance complexity increases
Solution Approach 1:
By combining the worm drive and lever arm into a single maintenance unit, the patent simplifies maintenance procedures. The integrated design means fewer separate components require individual inspection, adjustment, and repair, while the precision actuation is maintained through the inherent mechanical precision of the worm drive-lever arm configuration.
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 efficiently actuates surgical instruments with fewer parts, reducing manufacturing costs and improving maintenance, while providing high torque and low friction transmission to effectively operate surgical end effectors, such as forceps or other end effectors, with improved back-drivability to minimize damage.
Implementation Method 1
A surgical instrument with a worm drive and lever arm assembly that converts rotational movement into translational movement through a follower member and actuation element, utilizing a worm drive with a threaded section
Implementation Method 2
utilizing a worm drive with a threaded section and a lever arm that pivots or slides to efficiently transmit force with low friction
Implementation Method 3
a lever arm comprising a first end and a second end, the lever arm being pivotable about a pivot axis
Implementation Method 4
efficiently transmit force with low friction, allowing for both roll and translational movement of the actuation element
Data Source
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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.