Surgical Position Limiting Device with Interference Fit
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Solution Overview
Problem
Conventional ERCP surgical instruments face challenges in maintaining precise positioning and requiring significant force to adjust the sphincterotome, leading to potential movement and reduced service life due to friction forces.
Innovation Solution
A position limiting device with a clamping and movable ring structure that uses an interference fit for clamping and clearance fit for sliding, allowing for easy positioning and secure fixation without initial clamping force, featuring a pressing plate and groove for enhanced clamping, and made from durable plastic materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction force between cutting wire and cutting wire cavity is used for self-locking, then positioning function is maintained, but large force is needed for pulling the handle and the handle may move under action of force
Solution Approach 1:
The limiting device is divided into two separate functional portions: a clamping portion for maintaining positioning through interference fit, and a movable portion for enabling free sliding during adjustment. This segmentation allows each portion to perform its specific function optimally without the drawbacks of the other.
Solution Approach 2:
The limiting device transitions from a static friction-based self-locking mechanism to a dynamic system where the movable portion can slide freely during positioning adjustment, and only the clamping portion engages to maintain the final position. This dynamic behavior reduces the force needed during handle pulling while maintaining positioning reliability.
2Reliability
If clamping force is continuously applied to maintain positioning, then position limiting function is achieved, but device lifespan is reduced due to long-time placement deformation
Solution Approach 1:
By separating the clamping portion from the movable portion, the device can apply clamping force only when positioning is required, rather than continuously. The movable portion remains disengaged during normal operation, eliminating long-term deformation while maintaining positioning capability when needed.
Solution Approach 2:
The clamping force is applied periodically only during positioning operations rather than continuously. The movable portion allows free movement during adjustment phases, and only the clamping portion engages to maintain the final position, creating a periodic pattern of engagement that preserves device lifespan.
3Ease of operation
If movable portion is designed for free sliding, then ease of operation is improved, but positioning precision may be compromised
Solution Approach 1:
The device separates the sliding function (movable portion) from the positioning function (clamping portion). The movable portion provides free sliding for easy adjustment, while the clamping portion ensures precise positioning through interference fit with the core rod, eliminating the trade-off between ease of operation and positioning precision.
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
Facilitates fast and precise positioning with reduced operational force, prolongs device lifespan by avoiding long-term clamping-induced deformation, and maintains effective positioning even after extended use.
Implementation Method 1
the clamping portion and the core rod are in an interference fit, and the movable portion and the core rod are in a clearance fit
Implementation Method 2
the clamping portion and the core rod are in an interference fit, and the movable portion and the core rod are in a clearance fit
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The present invention relates to a limiting device; the limiting device comprises a clamping portion and a movable portion; the clamping portion and the movable portion are both annular structures, two ends of the clamping portion and the movable portion are respectively connected to form a connected double-ring structure, and the ring diameter of the movable portion is larger than the ring diameter of the clamping portion. The limiting device in the present invention is disposed on a core rod, the clamping portion and the core rod are in interference fit, and the movable portion and the core rod are in clearance fit. When the movable portion cooperates with the core rod, the limiting device may slide relative to the core rod; when the clamping portion cooperates with the core rod, the limiting device and the core rod are in a fixed state, and the limiting device cannot slide relative to the core rod, thus achieving the purpose of limiting. The limiting device may quickly carry out positioning, is convenient to operate, and may still achieve a limiting function after being placed for a long period of time.