Composite Cardan Stapler Drive for Consistent Torque Through Angles
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Solution Overview
Problem
Minimally invasive surgical techniques face challenges in providing precise mechanical actuation and control of surgical instruments, particularly in stapling tissue, due to limitations in existing torque transmission mechanisms that fail to efficiently transmit torque through angles while maintaining rotational speed consistency.
Innovation Solution
A surgical instrument with a composite Cardan and lead screw drive mechanism, incorporating a torque transmitting mechanism with plastic bearings and metal coupling members, which includes a cardan drive shaft, driven shaft, and double universal joints to transmit torque through angles while eliminating rotational speed differences, enabling precise stapling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional torque transmission mechanism is used, then the structure is simple, but the rotational speed consistency deteriorates when transmitting torque through angles
Solution Approach 1:
The patent applies composite materials by combining plastic bearings with metal coupling members in the universal joint assembly. The plastic bearings reduce friction and wear while the metal coupling members provide structural strength and precision, together achieving consistent rotational speed transmission through angles without excessive complexity
Solution Approach 2:
The patent introduces an intermediary mechanism - the double universal joint with cardan drive shaft - that mediates between the lead screw drive and the stapling jaws. This intermediary allows torque to be transmitted through angles while maintaining rotational speed consistency, resolving the contradiction between simple structure and reliable performance
2Measurement precision
If a lead screw drive mechanism is used, then precise linear actuation is achieved, but efficient torque transmission through angles deteriorates
Solution Approach 1:
The patent applies dynamics by using a double universal joint mechanism that can dynamically adapt to angular misalignments between the lead screw drive and the stapling jaws. The cardan drive shaft maintains rotational speed consistency while accommodating angular variations, ensuring efficient torque transmission without compromising linear actuation precision
Solution Approach 2:
The patent changes the parameter of rotational speed consistency through the cardan drive shaft design. By maintaining constant rotational speed despite angular variations, the system ensures that the lead screw drive's precise linear actuation capability is preserved while improving torque transmission efficiency through angles
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 precise and efficient mechanism for stapling tissue by ensuring consistent rotational speed and torque transmission, enhancing the dexterity and effectiveness of minimally invasive surgical procedures.
Implementation Method 1
A lead screw configured to advance the drive member in a distal direction parallel to the second jaw axis
Implementation Method 2
A first cam surface secured to the first jaw that includes a distal cam portion that extends parallel to the first jaw axis and a proximal cam portion that is inclined at an angle relative to the distal cam portion
Implementation Method 3
A first rotatable bearing has a first spherical surface formed of a plastic material
Data Source
AI summary
A surgical instrument is provided that includes a first jaw having a first jaw axis and that includes a proximal portion pivotally mounted to the base to be pivotable about a pivot axis between an open and a closed positions and including a distal portion; a second jaw having a second jaw axis and including a proximal portion secured to the base and including a distal portion; a first side edge secured to the first jaw a second side edge secured to the second jaw; a third side edge secured to the first jaw; a drive member including a cross-beam, which is sized to slideably engage the first, second and third side edges, a first transverse beam portion, and a second transverse beam portion; and a lead screw configured to advance the drive member in a distal direction parallel to the second jaw axis while engaging one or the other of the first and second side edges and the second side edge.