Lead Screw Drive Coupling for Precise Surgical Tool Adjustment
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Solution Overview
Problem
Medical device drive systems face challenges in precisely controlling surgical instruments due to space constraints and the need for precision and accuracy during minimally invasive surgeries, where existing systems struggle to efficiently manage multiple tools and operations within limited spaces.
Innovation Solution
A medical device drive system comprising a support structure, multiple drive members, and gears that allow for forward and backward movement, with a combination of back-drivable and non-back-drivable threaded interfaces, enabling coarse and fine adjustments, and allowing for the coupling and decoupling of components to facilitate precise control of surgical tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single drive system is used to control surgical instruments, then the device complexity is reduced, but the precision and accuracy of instrument control deteriorates
Solution Approach 1:
The drive system is segmented into multiple independent drive members (first drive member for coarse adjustment, second drive member for fine adjustment) that operate in series. Each drive member controls different aspects of the surgical instrument, allowing precise control through coordinated operation of multiple specialized components rather than a single complex component.
2Measurement precision
If multiple drive members are used to achieve precise control, then the precision of surgical instrument control is improved, but the device complexity increases
Solution Approach 1:
The second drive member is positioned within or alongside the first drive member, with the intermediate drive member coupling them in series. This nested arrangement allows multiple drive members to occupy limited space while maintaining their independent functions, reducing the overall space requirement compared to separate external drive systems.
Solution Approach 2:
The intermediate drive member serves multiple functions: it couples the first and second drive members, transmits motion between them, and provides a mechanism for selective engagement and disengagement. This multi-functional component reduces the need for additional separate components, thereby managing complexity.
3Ease of operation
If back-drivable threaded interfaces are used, then the ease of operation and adjustability are improved, but the control precision deteriorates due to potential backward movement
Solution Approach 1:
The system dynamically switches between back-drivable and non-back-drivable interfaces depending on the operational phase. The first drive member uses back-drivable threads for easy positioning, while the second drive member uses non-back-drivable threads for precise, locked positioning. This dynamic adaptation of interface properties optimizes both ease of operation and control precision at different stages.
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 system enables precise control and adjustment of surgical instruments, allowing for efficient operation of tools like surgical staplers, with the ability to perform both coarse and fine adjustments, improving the precision and accuracy of surgical procedures in minimally invasive surgeries.
Implementation Method 1
The first drive member can include a back-drivable threaded interface, and the first drive input can include a first drive input threaded interface that is engaged with the back-drivable threaded interface. The second drive member can include a second drivable threaded interface (e.g. a nut) and the intermediate drive member can include a second drivable threaded interface (e.g. threads on a lead screw)
Implementation Method 2
The intermediate drive member is a lead screw, the lead screw being rotatably coupled to the first drive member; and the second drive input is configured to turn the lead screw. The lead screw can include a threaded portion, and the second drive member can include a nut having threads engaged with the threaded portion of the lead screw
Implementation Method 3
The second drive input can include a drive gear that is coupled to the lead screw, and the system can further include a drive input gear that is operatively coupled with the drive gear
Data Source
AI summary
A medical device drive system including a lever body having portions defining a lever body cavity, a nut housing in the lever body cavity, and a first nut at least partially in the first nut cavity. The first nut is slideable in the first nut cavity between an engaged position in which the lead screw interface is engaged with the engagement portion of the lead screw, and a disengaged position in which the lead screw interface is not engaged with the engagement portion of the lead screw. The lead screw interface of the first nut is selectively engageable with the engagement portion of the lead screw by sliding the lever body and pin relative to the first nut housing.