Laparoscopic Tip Double-Threaded Connection
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Solution Overview
Problem
Current laparoscopic devices face energy losses due to difficulties in achieving a tight, low-electrical-resistance connection between coaxial thread forms, leading to inefficiencies in energy transfer and potential heat generation at the interface.
Innovation Solution
A removable tip with a double-threaded design, featuring an Edison thread on the outer tubing and a high helix angle thread on the inner shaft, along with insulation to prevent electrical contact, ensures low electrical resistance and efficient energy transfer while maintaining mechanical attachment and force transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw-type threaded interface is used to mechanically attach the tip and shaft, then mechanical attachment and force transfer are achieved, but electrical resistance increases and energy losses occur due to difficulty in achieving tight fit between coaxial thread forms
Solution Approach 1:
The threaded connection is segmented into two distinct thread forms: an outer screw-type thread for mechanical attachment and an inner high helix angle thread for electrical contact. This segmentation allows each thread to be optimized for its specific function, resolving the contradiction between mechanical reliability and electrical efficiency.
Solution Approach 2:
Different regions of the threaded interface have different qualities: the outer thread region provides mechanical strength and attachment reliability, while the inner thread region provides low electrical resistance for energy transfer. This local differentiation resolves the contradiction by assigning specific functions to specific regions.
2Use of energy by moving object
If coaxial thread forms are tightly fitted together to reduce electrical resistance, then energy transfer efficiency improves, but manufacturing difficulty increases due to tolerance and machining inaccuracies
Solution Approach 1:
The electrical and mechanical functions are segmented into separate thread forms, eliminating the need for perfect coaxial alignment. The outer thread handles mechanical attachment with standard tolerances, while the inner thread handles electrical contact, making manufacturing significantly easier while maintaining energy efficiency.
Solution Approach 2:
The inner high helix angle thread acts as an intermediary electrical pathway between the shaft and tip. This intermediary structure provides a dedicated low-resistance electrical path that is not dependent on the precision of the outer mechanical thread, resolving the manufacturing difficulty while maintaining energy efficiency.
3Loss of energy
If tight fitting of coaxial threads is attempted to reduce electrical resistance, then energy losses decrease, but heat generation at the interface increases due to friction and pressure
Solution Approach 1:
The segmentation of functions into separate thread forms reduces the contact pressure needed for mechanical attachment, thereby reducing frictional heat generation. The electrical function is handled by the inner thread which requires minimal pressure for low resistance, while the outer thread provides mechanical strength, collectively reducing heat generation while maintaining energy efficiency.
Solution Approach 2:
The local quality of the inner thread region is optimized for electrical contact with smooth, conductive surfaces that minimize resistive heating, while the outer thread region handles mechanical loads. This local differentiation reduces overall heat generation at the interface while maintaining low electrical resistance.
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 robust, cost-effective, and reliable connection with minimal unwanted heat generation, enabling efficient energy transfer and effective cutting and sealing of tissues during surgical procedures.
Implementation Method 1
a threaded connection between the shaft and the tip, the threaded connection including an Edison thread formed on the outer tubing and a high helix angle thread formed on the inner shaft
Implementation Method 2
The outer tubing and the inner shaft are made of metal or other electrically-conductive material. Insulation is provided between the inner shaft and the outer tubing to prevent electrical contact therebetween
Implementation Method 3
The threaded connection provides a pathway for transferring energy from the shaft to the tip
Implementation Method 4
A cutting and sealing device is attached at the distal end of the removable tip and includes a heating member
Data Source
Figure 1~2
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AI summary
A laparoscopic instrument assembly with a handle member and a removable tip. The handle member and removable tip are mated using a double threaded design which provides a secure connection with low electrical resistance. Electrical energy is provided through an inner shaft to the removable tip, and a return energy path is formed using an outer tubing of the instrument assembly. The removal tip includes a cutting and sealing device with a resistive member that is provided with the electrical energy, thereby enabling the tip to cut and seal tissue.