Retrograde Drill Blade Position Control via Cam Mechanism
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Solution Overview
Problem
Existing rotary cutting devices for arthroscopic surgeries, such as ACL reconstruction, face limitations in maintaining the blade position during retrograde drilling due to manual operation and lack of efficient position retention, leading to potential misalignment and reduced precision.
Innovation Solution
A rotary cutting device with a blade position control system that includes a connection system between the inner shaft and blade, allowing movement between aligned and nonparallel positions, and a position retention system using a cam and cam follower to securely maintain the blade in the nonparallel position for retrograde socket creation, preventing unintended repositioning during heavy resistance drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If manual operation is used to move the blade between positions, then the device structure can be simpler, but the precision and reliability of blade position control deteriorates
Solution Approach 1:
The patent replaces manual mechanical operation with an automated cam mechanism. The cam profile is precisely engineered to automatically guide the blade through predetermined positions (aligned, angled, and reamed positions) during rotation, eliminating manual positioning errors while maintaining relatively simple device structure through pure mechanical automation.
Solution Approach 2:
The cam mechanism is designed to automatically perform the blade positioning function during normal device rotation. The blade follower engages with the cam profile, and as the cam rotates, it self-adjusts the blade angle without requiring external manual intervention, making the system self-sufficient for position control.
2Ease of operation
If the blade is manually moved between positions, then the device can be easier to operate, but the reliability of maintaining blade position during drilling deteriorates
Solution Approach 1:
Manual blade repositioning operations are replaced by an automated cam mechanism that programmatically controls blade angle through its engineered profile. The cam ensures the blade automatically transitions to and maintains precise positions (0°, 30-60°, and reaming angles) during rotation, eliminating reliance on manual operator skill while maintaining ease of use through simple rotational activation.
Solution Approach 2:
The cam mechanism provides passive feedback control where the blade follower continuously engages the cam profile, automatically correcting any position deviations. As the cam rotates, its profile shape ensures the blade is constantly guided to the correct angle, providing inherent position verification and correction without active sensing systems.
3Productivity
If the blade can rotate freely for cutting, then the cutting efficiency is improved, but the blade may inadvertently return to the first position when encountering heavy resistance, worsening precision
Solution Approach 1:
The cam mechanism ensures continuous blade position control throughout the entire cutting rotation. The blade follower maintains constant engagement with the cam profile, ensuring the blade remains at the precise cutting angle (30-60°) throughout the entire rotational cycle, even under heavy bone drilling resistance, preventing any inadvertent position changes.
Solution Approach 2:
The cam acts as an intermediary mechanical element between the rotating drive shaft and the blade. It mediates the relationship between rotation and blade angle, ensuring that rotational motion is consistently translated to the correct blade orientation regardless of cutting resistance, thereby maintaining position consistency while enabling continuous cutting action.
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 device ensures precise retrograde socket creation by maintaining the blade's nonparallel position, preventing accidental repositioning and allowing rotary motion for effective bone cutting, enhancing surgical efficiency and safety by reducing manual repositioning needs and preventing lateral movement.
Implementation Method 1
The blade position control system includes a cam in communication with a cam follower and in communication with the inner shaft for moving the blade into first and second positions
Implementation Method 2
The blade position control system includes a cam in communication with a cam follower and in communication with the inner shaft for moving the blade into first and second positions
Data Source
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AI summary
A rotary, cutting medical device configured to be used during surgeries, such as ACL reconstruction, to drill holes and retrograde sockets is disclosed. The device may include a blade at a distal end that is movable between a first position aligned with a longitudinal axis of the device and a second position nonparallel to the longitudinal axis used to create retrograde sockets. The device may include a blade position control system connecting the blade to distal ends of both the outer tube and inner shaft and configured to control movement of the blade between first and second positions for drilling a hole and then creating a retrograde socket. The device may include a position retention system configured to retain the blade in the second position while allowing the inner shaft and blade to rotate to cut the socket.