Planetary Gear Actuation Assembly for Low-Friction Force Transmission
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Solution Overview
Problem
Existing force transmission systems in instruments face challenges such as complex manufacturing processes, limited flexibility in actuation member routing, and increased friction due to twisting issues, which complicate the automation of manufacturing and reduce the reliability of force transmission for actuatable components.
Innovation Solution
The implementation of a force transmission system using a ring gear and planet gears with lead screws, allowing for independent control of actuation members and maintaining preload tension without transmitting it to other drive members, enabling modular design and simplified manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If tension-type actuation members are routed around pulleys or capstans to reach the drive member, then the actuation members can be flexible in multiple degrees of freedom, but the manufacturing process becomes more complex and pre-tensioning cannot occur until after assembly
Solution Approach 1:
The patent removes pulleys, capstans, and other routing mechanisms from the force transmission system. Instead, actuation members are coupled directly to drive members (lead screws, planetary gears) in a streamlined configuration that eliminates intermediate routing components, thereby reducing manufacturing complexity while maintaining flexibility.
Solution Approach 2:
The force transmission system is divided into modular components where drive members (lead screws, planetary gears) are segmented and positioned to directly interface with actuation members. This segmentation allows for simplified assembly and pre-tensioning of individual modules before final integration.
2Manufacturing precision
If pre-tensioning is applied to remove slack in actuation members, then accurate movement and positioning of articulable components is achieved, but the manufacturing process becomes more complex particularly with directional changes
Solution Approach 1:
The patent enables pre-tensioning of actuation members to be performed during the manufacturing process before final assembly. Drive members are configured to allow pre-tensioning operations to occur on individual components, removing slack and ensuring accurate positioning capability before the components are integrated into the complete instrument.
Solution Approach 2:
By eliminating pulleys and capstans that require complex routing, the patent simplifies the pre-tensioning process. Actuation members can be directly tensioned against drive members without navigating around intermediate components, making the pre-tensioning operation easier to perform during manufacturing.
3Ease of operation
If rotary drive members such as capstans are used to drive tension actuation members, then rotational motion can be converted to linear motion, but the actuation members must follow complex paths and routing mechanisms are required
Solution Approach 1:
The patent eliminates capstans and pulleys from the system. Instead of using rotary capstans to wind and pay out cables, the invention uses lead screws and planetary gears that directly convert rotational motion to linear motion of actuation members, removing the need for complex routing paths and intermediate routing mechanisms.
Solution Approach 2:
The patent replaces the capstan-cable winding mechanism with a lead screw-threaded rod mechanism. This substitution provides direct conversion of rotational to linear motion without requiring the cable to follow complex paths around rotating components, thereby reducing routing complexity.
4Adaptability or versatility
If multiple actuation members are used to control multiple degrees of freedom, then comprehensive control of actuatable components is achieved, but the routing and operable coupling of multiple actuation members complicates manufacturing automation
Solution Approach 1:
The patent segments the force transmission system into modular drive member units (lead screws, planetary gears) that can be independently manufactured and assembled. Each drive member interfaces directly with its corresponding actuation member, allowing for automated assembly processes where multiple actuation members are coupled to multiple drive members in a systematic, repeatable manner without complex routing operations.
Solution Approach 2:
By removing pulleys, capstans, and routing mechanisms, the patent eliminates the complex routing operations that would need to be performed manually or with complex automated equipment. The direct coupling of multiple actuation members to multiple drive members simplifies the manufacturing process and enables greater automation.
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 simplifies the manufacturing process, reduces friction, and enhances the reliability of force transmission by isolating preload tension to the actuation member drive assembly, allowing for automated assembly and modular interfacing with various drive inputs, while maintaining desired tension states regardless of external forces or instrument connectivity.
Implementation Method 1
a force transmission system using a ring gear and planet gears with lead screws
Implementation Method 2
ring gear and planet gears with lead screws, allowing for independent control of actuation members
Data Source
AI summary
An instrument includes a shaft, a moveable component coupled to the shaft, and an actuation member drive assembly coupled to the shaft. The actuation member drive assembly may include a rotatable drive member, a ring gear operably coupled to the rotatable drive member and configured to rotate in response to rotation of the rotatable drive member, and a planet gear meshed with the ring gear. The instrument further includes an actuation member extending through the shaft and operably coupled to the moveable component and the planet gear. The actuation member is moveable in translation in response to rotation of the planet gear. Devices and methods relate to actuation member drive assemblies.