Endoscopic Clevis Axle Retention via Flared Grooves
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Solution Overview
Problem
Current endoscopic medical device clevis designs, such as those with cast clevises, face challenges in maintaining structural integrity and alignment during manufacturing and use, particularly in preventing axial shifting of the axle and end effector assembly, which can lead to dislodgment during actuation.
Innovation Solution
A clevis assembly with a base and multiple arms, where the axle extends between the arms, featuring a flared portion at one end to engage the outer surface of the arms, and U-shaped grooves for axle retention, enhances stability and manufacturability by providing a secure press-fit and alignment aid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cast clevis design with through hole and riveting is used, then the axle can be secured to the distal arms, but axial shifting of the axle and end effector assembly can occur leading to dislodgment during actuation
Solution Approach 1:
The clevis arms feature localized grooves at specific positions where the axle contacts the arms. These grooves create localized retention features that prevent axial shifting while maintaining the overall simplicity of the cast clevis structure. The grooves are positioned to engage with corresponding features on the axle, providing targeted stabilization without requiring complete redesign of the entire assembly.
Solution Approach 2:
The grooves are pre-formed as integral features of the cast clevis arms before assembly. This preliminary formation of retention features ensures that when the axle is inserted and riveted, the axial alignment is already established and maintained. The grooves prepare the interface between axle and arms to prevent shifting during subsequent actuation, eliminating the need for additional alignment steps.
2Ease of manufacture
If traditional clevis designs are used, then the distal assembly can be connected to the elongate member, but manufacturing precision and alignment accuracy are difficult to maintain
Solution Approach 1:
The grooves are cast as integral features of the clevis arms during the primary manufacturing process. This preliminary formation of precise retention features ensures that alignment accuracy is built into the component itself, rather than requiring costly post-processing or complex assembly procedures to achieve proper axle positioning.
Solution Approach 2:
The grooves in the clevis arms and corresponding features on the axle work together as a self-aligning mechanism. During assembly, the groove features automatically guide the axle into the correct position, and during operation, they maintain alignment without requiring external adjustment or intervention. This self-service alignment system maintains manufacturing precision while simplifying the overall assembly process.
Data Source
AI summary
Embodiments of the invention relate to endoscopic instruments. More particularly, embodiments of the invention relate to features on the clevis portion of endoscopic instruments. The clevises may be formed from a sheet material to obtain a substantially cylindrical end and at least one clevis arm. The clevis features may include an axle having at least one flared end to engage a clevis arm, one or more U-shaped grooves on the clevis arms to receive an axle, and stiffening ribs to strengthen the clevis arms.