Piercing Needle-Equipped Cannula Slit Deformation
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Solution Overview
Problem
Existing piercing needle-equipped cannulas experience deformation of the slit portion after the piercing needle is removed, leading to gaps and leakage of vitreous humor during ophthalmic operations.
Innovation Solution
A piercing needle-equipped cannula design featuring a slit piercing part with a cross-sectional area smaller than the needle main body, made from a different or flexible material, and having a flat rectangular or curved shape to minimize deformation, ensuring the slit remains tightly closed after the needle is pulled out.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a piercing needle with the same cross-sectional area as the needle main body is used, then the needle can be easily manufactured, but the slit portion deforms after the needle is removed causing leakage
Solution Approach 1:
The patent applies parameter changes by modifying the cross-sectional area of the slit piercing part relative to the needle main body. Specifically, the slit piercing part is designed with a smaller cross-sectional area than the needle main body, creating a size differential that prevents excessive deformation of the slit portion when the needle is inserted and removed. This parameter adjustment resolves the contradiction by maintaining manufacturing simplicity while improving sealing reliability.
2Ease of operation
If a piercing needle with a large cross-sectional area is used, then the needle can be easily inserted, but the slit portion deforms significantly after removal
Solution Approach 1:
The patent applies parameter changes by optimizing the cross-sectional dimensions of the slit piercing part. By setting its cross-sectional area to be smaller than that of the needle main body, the design balances insertion ease with shape preservation. The reduced cross-sectional area of the piercing part minimizes the deformation imposed on the slit during insertion and ensures proper closure after removal, thus resolving the contradiction between ease of operation and shape maintenance.
3Shape
If the piercing needle cross-sectional area is reduced, then slit deformation is minimized, but the needle becomes harder to manufacture
Solution Approach 1:
The patent applies parameter changes by establishing a specific size relationship between the slit piercing part and the needle main body. The cross-sectional area of the slit piercing part is set to be smaller than that of the needle main body, but not excessively small. This controlled parameter adjustment achieves the dual benefit of minimizing slit deformation while maintaining reasonable manufacturability, thus resolving the contradiction between shape preservation and manufacturing ease.
Data Source
Figure 1(a)~2(c)
Figure 3(a)~3(c)
Figure 4(a)~5
AI summary
There is provided a piercing needle-equipped cannula that has a pre-attached piercing needle, and no deformation of the slit portion due to the piercing needle is left after the piercing needle is pulled out. A piercing needle-equipped cannula (100) includes: a cannula (10) pierced in an eyeball and used in ophthalmic operations; a resin cap (13) having a slit (13a) opened in the cannula (10); and a piercing needle (15) attached to the cannula (10). The piercing needle (15) includes a needle main body (15c) on a front end side, a base (15d) on a base end side, and a slit piercing part (15s) piercing the slit (13a) in a state where the needle main body (15c) and the base (15d) are connected, and the cross-sectional area of the slit piercing part (15s) is smaller than that of the thickest part of the needle main body (15c).