Oscillating Rotary Surgical Tool Transmission Mechanism
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Solution Overview
Problem
Current surgical tools with rotary cutters face challenges when encountering fibrous tissues like muscle and nerves, as these tissues can wrap around the cutter and get damaged. Additionally, existing oscillating rotary tools do not operate smoothly due to the mechanisms used to effect oscillation.
Innovation Solution
A surgical tool with a housing, a cutter support shaft connected to a motor for oscillating rotation, and a drive transmission system that allows for selective oscillating rotary movement and non-oscillating rotation in two rotational directions, enabling the tool to operate in multiple modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotary cutter is used to modify tissue, then cutting efficiency is improved, but fibrous tissue can wrap around the cutter and get damaged
Solution Approach 1:
The patent applies periodic oscillation to the rotary cutter, causing it to alternate between rotational directions (e.g., clockwise and counter-clockwise) at high frequencies (e.g., 10,000-50,000 oscillations per minute). This periodic reversal prevents fibrous tissue from wrapping around the cutter by continuously changing the cutting direction, thereby maintaining cutting efficiency while protecting fibrous tissues from damage.
2Object-affected harmful factors
If oscillation mechanism is added to rotary cutter, then protection against fibrous tissue damage is improved, but device complexity increases
Solution Approach 1:
The patent merges the oscillation mechanism with the existing rotary drive system, combining both functions into a single integrated assembly. The oscillation is achieved through a linkage mechanism that couples to the rotary motor, allowing the cutter to perform both rotation and oscillation simultaneously without requiring separate independent systems, thus reducing overall device complexity.
Solution Approach 2:
The oscillation mechanism is designed to work with the existing rotary cutter assembly, enabling a single device to perform multiple functions: rotary cutting, oscillating cutting, and potentially reciprocating motion. This multi-functionality reduces the need for separate tools and simplifies the overall surgical instrument system.
3Productivity
If high cutting speed is used, then cutting efficiency is improved, but vibration increases and smooth operation deteriorates
Solution Approach 1:
The high-frequency oscillation (10,000-50,000 oscillations per minute) creates a periodic cutting action that prevents the buildup of vibration. By continuously reversing the cutting direction at high frequency, the oscillation mechanism counteracts the natural vibration frequencies of the cutter and workpiece, resulting in smoother operation despite high cutting speeds.
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 tool effectively modifies and removes hard tissues like bone, cartilage, and discs with reduced risk of damaging fibrous tissues, while operating smoothly due to the advanced drive transmission system, allowing for both oscillating and non-oscillating modes.
Implementation Method 1
a cutter support shaft connected to a motor for oscillating rotation
Implementation Method 2
a drive transmission system that allows for selective oscillating rotary movement and non-oscillating rotation in two rotational directions
Data Source
AI summary
A surgical tool that has a pair of transmissions coupled to one another to effect driving of a cutting tool in both bidirectional intermittent rotational manners and in opposite directions of continuous rotation. The transmissions are driven by a motor coupled to one of the transmissions which is coupled to the second transmission.