Rigid Needle Shield With Flexible Member To Prevent Recoil
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Solution Overview
Problem
Rigid needle shields can cause accidental needle stick injuries due to the initial pull-off force and recoil phenomenon when trying to remove them from a syringe, leading to potential hand contact with the uncovered needle.
Innovation Solution
A rigid needle shield design featuring an open proximal end, closed distal end, and an elongated flexible member that can move between a relaxed and flexed position, allowing the second end to extend beyond the open proximal end to engage the needle hub and shoulder, reducing the need for significant tensile force to remove the shield from the syringe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid needle shield is designed to be securely attached to the syringe, then the shield provides reliable protection during use, but significant pull-off force is required to remove the shield which causes recoil and accidental needle stick injuries
Solution Approach 1:
The shield attachment system is segmented into multiple interaction points: the flange engages with the shoulder, the tail engages with the undercut, and the flexible member provides additional retention. This segmentation allows the shield to be securely attached during use but enables controlled removal by sequentially disengaging these segments, reducing the sudden pull-off force that causes recoil.
Solution Approach 2:
The flexible member is pre-positioned to engage the tail of the shield with the undercut of the syringe barrel before use. This preliminary engagement creates a mechanical interlock that secures the shield during injection but can be easily released by deflecting the flexible member, allowing controlled removal without sudden pull-off force.
2Ease of manufacture
If the needle shield uses a simple snap-fit attachment, then the device is easy to manufacture and cost-effective, but the attachment and detachment forces create recoil that causes accidental needle stick injuries
Solution Approach 1:
The attachment system transitions from a static snap-fit to a dynamic system with a flexible member that can deflect. The flexible member allows controlled deformation during removal, converting the sudden pull-off force into a gradual release mechanism. This dynamic approach maintains manufacturing simplicity while eliminating the harmful recoil effect.
Solution Approach 2:
The flexible member changes the mechanical parameters of the attachment system by introducing flexibility and controlled compliance. This allows the attachment strength to be maintained during use while enabling easy, controlled removal by deflecting the flexible member, thereby changing the force profile from sudden to gradual and eliminating recoil.
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
The flexible member's deflection generates a mechanical force to overcome the initial pull-off force, reducing the risk of accidental needle stick injuries by eliminating the need for significant tensile force and preventing the shield from recoiling back towards the needle.
Implementation Method 1
The middle portion is also deflectable to move the elongated flexible member between a first relaxed position and a second flexed position wherein the second end extends beyond the open proximal end
Data Source
AI summary
A rigid needle shield for covering a distal end of a syringe is provided. The rigid needle shield includes an elongated flexible member connected to a sidewall of the rigid needle shield for moving the rigid needle shield between a first relaxed position and a second flexed position. When in the first relaxed position, the elongated flexible member is substantially within the rigid needle shield. However, when the elongated flexible member is moved to the second flexed position, the elongated flexible member extends beyond a proximal end of the rigid needle shield to engage a needle hub or a shoulder of the syringe to move the rigid needle shield distally relative to the syringe.