Endoscopic Instrument Rotatable Clevis Mechanism
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Solution Overview
Problem
Existing endoscopic surgical instruments face challenges in navigating non-flexible bends within the working channel of an endoscope due to rigid designs, which limits the length and flexibility of end effectors that can be inserted, and often require high manufacturing tolerances and are costly to produce.
Innovation Solution
The design incorporates a cam-slot and cam-pin operation that allows end effectors to rotate together when fully closed, enabling passage through non-flexible bends, with a push rod and cam-pin construction that reduces manufacturing costs and requires lower tolerances, and includes a tissue stop mechanism for enhanced tissue traction and a rotatable clevis assembly for precise manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid end effector designs are used, then structural integrity is maintained, but the ability to navigate non-flexible bends is compromised
Solution Approach 1:
The end effector is designed with a rotatable clevis assembly that allows dynamic rotation about the longitudinal axis. This enables the rigid end effector to adapt its orientation when encountering non-flexible bends in the working channel, while maintaining structural integrity during cutting operations. The rotation capability is achieved through a cam-slot and cam-pin mechanism that permits controlled rotational movement.
Solution Approach 2:
The invention adds rotational freedom in the longitudinal dimension, allowing the end effector to rotate about its axis while maintaining its rigid structure. This dimensional addition enables navigation through bent pathways without compromising the structural integrity of the cutting elements.
2Manufacturing precision
If high manufacturing tolerances are applied, then precision of end effector operation is improved, but manufacturing cost increases
Solution Approach 1:
The cam-slot and cam-pin mechanism is designed with optimized geometric parameters that provide precise control of end effector rotation and opening/closing motion without requiring extremely tight manufacturing tolerances. The cam profile and slot dimensions are specifically configured to achieve accurate rotational manipulation while being manufacturable with standard tolerances, thereby reducing production costs.
3Length of moving object
If longer end effectors are used, then operational reach is improved, but ability to pass through non-flexible bends is reduced
Solution Approach 1:
The rotatable clevis assembly with cam-slot and cam-pin mechanism enables longer end effectors to navigate bends by allowing rotational movement during insertion. The dynamic rotation capability compensates for the increased length, permitting the end effector to follow the bent path of the working channel while maintaining its longer operational reach.
Data Source
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AI summary
An endoscopic instrument includes a control wire having a push rod at its distal end and an end effector assembly having first and second effector elements such as scissors blades mounted on a clevis. The effector elements are operated by a cam-pin on the push rod riding in cam-slots defined in the effector elements. According to one aspect of the invention, the effector elements are symmetrically opened even when the push rod is canted relative to the clevis. According to another aspect of the invention, the effector elements can be rotated into a closed configuration that minimizes the distal dimension across the effector elements. In addition, the effector elements, when in the closed configuration, can rotate together to facilitate insertion of the end effector into an entry portion of an endoscope.