Preloaded Surgical Instrument Interface for Zero-Backlash Torque Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing surgical instruments with backlash issues adversely affect the transmission of controlled torque and position, leading to unpredictable motion during installation and operation, which is unacceptable for precise medical procedures.
Innovation Solution
A surgical instrument manipulator assembly with a mechanical interface that includes a drive output disk and intermediate disk, utilizing alignment elements, preload springs, and hard stops to achieve low backlash, ensuring precise alignment and zero backlash for torque levels used in surgical procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical interface with gears or disks is used to couple the drive system to the surgical instrument, then the transmission of torque and motion is enabled, but backlash occurs leading to unpredictable motion and loss of precision
Solution Approach 1:
The patent applies preliminary action by pre-loading the drive output disk against the intermediate disk using springs before operation. This pre-loading eliminates backlash by maintaining constant contact between the disk surfaces, ensuring that no gap exists to cause unpredictable motion during surgical procedures. The pre-load force is applied in advance to counteract any separation that would occur during torque transmission.
Solution Approach 2:
The patent changes the physical state of the mechanical interface by introducing pre-load forces that alter the contact conditions between disks. By adjusting the normal force between the drive output disk and intermediate disk through spring pre-loading, the system transitions from a state with potential gaps to a state of continuous contact, thereby eliminating backlash while maintaining torque transmission capability.
2Manufacturing precision
If alignment elements are added to ensure proper orientation of the drive output disk, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the alignment function with the existing disk structure by incorporating alignment elements directly into the drive output disk and intermediate disk. Rather than adding separate alignment mechanisms, the alignment features are integrated as part of the disk assembly, reducing overall device complexity while achieving precise orientation. The alignment elements are combined with the torque transmission interface in a unified structure.
3Manufacturing precision
If a preload force is applied to eliminate backlash, then manufacturing precision is improved, but the force required to operate the system increases
Solution Approach 1:
The patent applies dynamics by using compliant spring elements to provide the pre-load force rather than rigid mechanical constraints. The springs dynamically adjust to maintain optimal contact force between the disks, allowing the system to accommodate variations in torque requirements while eliminating backlash. This dynamic approach ensures consistent precision across different operating conditions without requiring excessive force.
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 solution provides a surgical instrument system with low backlash, allowing for precise control and predictable motion, enhancing the reliability and accuracy of surgical instruments during medical procedures.
Implementation Method 1
a pre-load force is applied to the drive output disk
Implementation Method 2
The mechanical interface has zero backlash for torque levels used in surgical procedures
Data Source
AI summary
A surgical system includes a surgical instrument that is sensitive to backlash that would adversely affect the transmission of controlled torque and position to the surgical instrument. The surgical instrument is coupled to motors in a surgical instrument manipulator assembly via a mechanical interface. The combination of the mechanical interface and surgical instrument manipulator assembly have low backlash, e.g., less than 0.7 degrees. The backlash is controlled in the surgical instrument manipulator assembly. From the drive output disk in the surgical instrument manipulator assembly to the driven disk of the surgical instrument, the mechanical interface has zero backlash for torque levels used in surgical procedures.