Surgical Articulation Assembly With Opposed-Thread Rod Control
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Solution Overview
Problem
Existing surgical instruments face challenges in providing a robust and controlled articulation of the end effector, limiting access to target tissue during laparoscopic or endoscopic procedures due to the limited space available through small incisions.
Innovation Solution
A surgical instrument with an articulation assembly comprising a threaded rod, two nuts, and two articulation rods, where rotation of the threaded rod in opposite directions causes the nuts to translate in opposite longitudinal directions, thereby moving the articulation rods and the end effector to achieve controlled articulation, allowing movement from a aligned position to an angled position up to 90° relative to the instrument's longitudinal axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional articulation mechanism is used, then the structure is simpler, but the control precision and robustness of end effector articulation deteriorates
Solution Approach 1:
The articulation assembly is segmented into multiple independent components: a threaded rod with first and second threads, a first nut engaged with the first thread, a second nut engaged with the second thread, a first articulation rod coupled to the first nut, and a second articulation rod coupled to the second nut. This segmentation allows each component to perform a specific function while maintaining overall system robustness and control precision.
Solution Approach 2:
The first and second threads are integrated into a single threaded rod body, allowing simultaneous control of both articulation rods through one rotational input. The first nut and second nut are positioned on the same threaded rod, enabling coordinated movement of both articulation rods through a unified mechanical linkage.
2Adaptability or versatility
If the end effector is constrained to a straight alignment, then the structure is simpler, but the ability to access target tissue through limited incisions deteriorates
Solution Approach 1:
The articulation assembly enables dynamic positioning of the end effector relative to the instrument body. The threaded rod can rotate to convert rotational motion into linear displacement of the nuts, which in turn moves the articulation rods to articulate the end effector between an aligned position and an angled position, providing adaptability for accessing target tissue through limited incisions.
Solution Approach 2:
The first and second articulation rods act as intermediary elements between the threaded rod mechanism and the end effector. These rods transmit the motion generated by the nuts to the end effector, enabling controlled articulation while maintaining a clear separation between the actuation mechanism and the end effector itself.
3Ease of operation
If a single-threaded rod is used, then the structure is simpler, but the ability to achieve simultaneous opposing movements of articulation rods deteriorates
Solution Approach 1:
The threaded rod incorporates asymmetric threading: a first thread with a first pitch and a second thread with a second pitch, where the pitches differ. This asymmetric design allows the first nut and second nut to move in opposite directions when the threaded rod rotates, enabling the first and second articulation rods to achieve simultaneous opposing movements for precise end effector articulation.
Solution Approach 2:
The threaded rod's rotation creates periodic linear displacement of the first and second nuts along the rod's axis. As the threaded rod rotates, the nuts move back and forth in a periodic manner, converting continuous rotational motion into controlled reciprocating linear motion that drives the articulation rods and enables precise articulation of the end effector.
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 enables precise and controlled articulation of the end effector, improving access to target tissue by allowing simultaneous pushing and pulling movements, enhancing the instrument's versatility and efficacy in surgical procedures.
Implementation Method 1
The threaded rod includes a body, a first thread encircling a proximal portion of the body in a first direction, and a second thread spaced from the first thread and encircling a distal portion of the body in a second direction. The first direction is opposite the second direction. The first nut is mechanically engaged with the first thread such that rotation of the threaded rod in a first direction relative to the elongated portion causes the first nut to move distally relative to the threaded rod. The second nut is mechanically engaged with the second thread such that rotation of the threaded rod in the first direction relative to the elongated portion causes the second nut to move proximally relative to the threaded rod.
Data Source
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AI summary
A surgical instrument includes an articulation assembly having a threaded rod, a first nut, a second nut, a first articulation rod, and a second articulation rod. The threaded rod includes a body, a first thread encircling a proximal portion of the body in a first direction, and a second thread spaced from the first thread and encircling a distal portion of the body in a second, opposite direction. Rotation of the threaded rod in a first direction relative to the elongated portion causes the first nut to move distally relative to the threaded rod. Rotation of the threaded rod in the first direction relative to the elongated portion causes the second nut to move proximally relative to the threaded rod. The first articulation rod is coupled to the first nut and the end effector, and the second articulation rod is coupled to the second nut and the end effector.