Safety Catheter Tip Protector Segmented Inner Outer Member Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing safety catheters with tip protectors face issues such as scraping along the needle shaft during use, which can be problematic, especially in passive tip protectors, and require higher removal forces in active tip protectors, while recent proposals to separate engagement and protection functions still have drawbacks.
Innovation Solution
The design incorporates axially shiftable members with a thin-walled metal outer member and a multi-thickness plastic inner member, where the inner member is completely within the outer member, featuring flexible tabs for securement and tapered bore portions to prevent distal re-emergence of the needle tip, reducing forces and improving ease of removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a passive tip protector design is used where the needle shaft urges the arms radially outwardly into engagement with the catheter hub, then the clip is easily removed from the hub, but the needle shaft experiences excessive scraping forces along the arms
Solution Approach 1:
The tip protector is divided into two separate members: an outer member that engages with the catheter hub and an inner member that protects the needle tip. This segmentation allows the outer member to handle engagement forces independently, preventing those forces from being transmitted to the needle shaft and causing scraping.
Solution Approach 2:
The outer member acts as an intermediary between the needle shaft and the catheter hub. It absorbs and isolates the engagement forces, preventing direct contact and friction between the needle shaft and the hub structure during removal operations.
2Object-affected harmful factors
If an active tip protector design is used where the clip arm remains urged into engagement with the catheter hub even in the fired position, then the scraping forces on the needle shaft are reduced, but higher removal forces are required to overcome the engagement
Solution Approach 1:
By separating the engagement function (outer member) from the protection function (inner member), the design allows the inner member to be easily removed without requiring force to overcome hub engagement, while the outer member maintains its engaged position to prevent scraping.
Solution Approach 2:
The outer member serves as a mediator that maintains engagement with the hub during the protected state, preventing harmful scraping forces, while the inner member can be independently removed without requiring force to overcome engagement constraints.
3Force
If recent proposals separate the catheter hub engagement function from the protective function using an outer member and clip, then easy removal is achieved with reduced forces, but the clip must be partially exposed distally of the outer member creating structural complexity
Solution Approach 1:
The inner member is completely nested within the outer member, with the inner member's outer surface conforming to the inner surface of the outer member. This nesting arrangement eliminates the need for the clip to be partially exposed distally of the outer member, simplifying the overall structure while maintaining the benefits of separated engagement and protection functions.
Solution Approach 2:
The distal ends of the outer and inner members are positioned adjacent to one another, creating a unified protective structure that appears as a single integrated component from the distal view, thereby reducing structural complexity while maintaining functional separation.
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
This configuration minimizes forces between the needle shaft and the tip protector during use, enhances securement and release of the tip protector, and reduces the risk of needle tip re-emergence, addressing the drawbacks of previous designs by providing a more efficient and user-friendly solution.
Implementation Method 1
two resilient arms can be inserted into a catheter hub and engage a feature of the catheter hub
Implementation Method 2
The inner member has tapered bore portions that cooperate to define a passageway having a cross dimension that is less than a cross dimension of the needle shaft adjacent the needle tip
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A safety catheter includes a catheter hub (16), a catheter tube (18), a needle hub (20), a needle cannula (22) having a distal tip (24), and a tip protector (30). The tip protector (30) includes an outer member (34) having a flexible tab (130) configured to releasably engage with the catheter hub (16) and release therefrom upon inward flexing of the tab (130). An inner member (32) is positioned entirely within the outer member (34) and has a portion (64) that impedes inward flexing of the tab (130) when disposed adjacent thereto. The inner member (32) is axially shiftable relative to the outer member (32) between a first position wherein the needle tip (22) is distal of the tip protector (30) and the inner member portion (64) is disposed adjacent the tab (130) to impede release from the catheter hub (16), and a second position wherein the tip (22) is within the outer member (34) and the inner member portion (64) is no longer adjacent the tab (130) and no longer impedes release from the catheter hub (16).