Surgical Rotation Stop Mechanism for Compact Over-360° Travel
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Solution Overview
Problem
Existing rotation stop devices in surgical instruments typically limit rotation to less than 360 degrees and are often bulky, making it difficult to achieve limited rotation in a range greater than 360 degrees while maintaining a low profile for packaging within instruments.
Innovation Solution
A surgical instrument with a rotation stop device that includes a threaded shaft and nut mechanism, allowing the knob to rotate relative to the handle in a range greater than 360 degrees, with a sensor to detect rotational position and correct image displays, and features like spring tabs and a potentiometer for precise control and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed mechanical stops are used to limit rotation, then rotation is limited to less than 360 degrees, but the device becomes bulky and difficult to package
Solution Approach 1:
The rotation stop device is nested within the handle assembly, with the threaded shaft and nut mechanism integrated into the existing structure. The distal handle portion is received within a cavity of the articulation housing, allowing the rotation stop functionality to be contained within the existing device footprint without adding external bulk.
Solution Approach 2:
The invention transitions from discrete angular stops (0D/1D limitation) to continuous rotational limitation along the longitudinal axis (1D to 3D space utilization). The threaded shaft and nut mechanism allows rotation along the longitudinal axis while limiting the degree of rotation, utilizing the third dimension (longitudinal depth) to achieve rotation control without increasing lateral dimensions.
2Reliability
If rotation is limited to less than 360 degrees, then components are protected from damage, but the operational range is insufficient for applications requiring greater than 360 degrees rotation
Solution Approach 1:
The rotation stop mechanism is designed to be dynamic rather than static, allowing the distal handle portion to rotate through more than 360 degrees along the longitudinal axis. The threaded shaft and nut mechanism provides continuous rotational limitation rather than discrete stops, enabling adaptable rotation ranges that can be adjusted by modifying the thread pitch and engagement length.
Solution Approach 2:
The invention changes the parameter of rotation limitation from discrete angular positions to continuous rotational degrees along the longitudinal axis. By adjusting the thread pitch, lead, and engagement length of the threaded shaft and nut mechanism, the rotation range can be precisely controlled to accommodate different application requirements while maintaining component protection.
3Volume of moving object
If a low profile design is used for packaging, then the device fits within instruments, but existing rotation stop mechanisms cannot achieve greater than 360 degrees rotation
Solution Approach 1:
The rotation stop mechanism is segmented into distinct functional components: the threaded shaft integrated with the distal handle portion, the nut integrated with the articulation housing, and the spring tabs providing rotational limitation. This segmentation allows each component to be optimized for its specific function while maintaining a compact overall profile that fits within the instrument constraints.
Solution Approach 2:
The invention utilizes the longitudinal dimension (axis along the length of the instrument) to achieve greater than 360 degrees rotation capability. The threaded shaft extends along the longitudinal axis, and the nut travels along this shaft during rotation, converting rotational motion into linear motion along the third dimension. This allows compact lateral dimensions while providing extensive rotational range.
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
Enables limited rotation of surgical instrument components in a range greater than 360 degrees while maintaining a low profile, preventing damage to components like wires and optical fibers, and facilitating precise image adjustment in surgical applications.
Implementation Method 1
The rotation stop can include a threaded shaft mated to a threaded nut, the threaded shaft being configured to rotate with the knob and the nut being non-rotatably captured by the handle
Implementation Method 2
The instrument can include a potentiometer having a shaft coupled to or formed integrally with the threaded shaft
Data Source
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AI summary
Surgical instruments with rotation stop devices and related methods are disclosed herein, e.g., for providing limited rotation between first and second components of the surgical instrument in a range greater than 360 degrees. Exemplary rotation stop devices can have a low profile and can include various features to facilitate packaging of the device within a larger instrument.