Syringe Backstop Preventing Plunger Separation
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Solution Overview
Problem
The process of reconstituting lyophilized medicines into solutions often results in difficulties when withdrawing the dissolved medicine from the vial into a syringe, leading to unintended plunger separation and loss of sterility, requiring reconstitution again and extending patient wait times.
Innovation Solution
A backstop device is designed for syringes, featuring a base with a skirt and extensions that attach to the syringe flange, preventing unintentional plunger withdrawal by engaging with the plunger's projections and flange, ensuring secure attachment and preventing accidental separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the plunger is partially withdrawn to withdraw dissolved medicine into the syringe, then the medicine can be transferred from the vial to the syringe, but the plunger may be inadvertently pulled out of the barrel causing loss of sterility and requiring reconstitution
Solution Approach 1:
The backstop device serves as an intermediary component between the plunger and the syringe barrel. It features a base with a skirt that extends into the barrel and extensions that engage with the plunger, creating a mechanical linkage that prevents the plunger from being accidentally withdrawn while still allowing intentional withdrawal for medicine transfer.
Solution Approach 2:
The backstop device applies preliminary anti-action by providing a mechanical barrier that counteracts the force of unintended plunger withdrawal. The extensions engage with the plunger projections before accidental separation can occur, and the skirt provides frictional resistance within the barrel to prevent inadvertent movement of the plunger.
2Productivity
If the plunger is pulled out to withdraw medicine, then the medicine can be transferred, but the sterility of the product is lost and patient wait time increases
Solution Approach 1:
The backstop device is attached to the syringe before the medicine withdrawal process begins. This preliminary action ensures that the plunger is secured in place, preventing accidental withdrawal during the medicine transfer process. By establishing this protective mechanism in advance, the device eliminates the need for reconstitution if accidental separation occurs.
3Reliability
If the backstop device is attached to the syringe flange, then plunger separation is prevented, but the device complexity increases
Solution Approach 1:
The backstop device is segmented into distinct functional components: a base with a skirt that provides frictional engagement within the barrel, and extensions with ledges that engage with the plunger projections. This segmentation allows each component to perform its specific function while keeping the overall device relatively simple in structure.
Solution Approach 2:
The backstop device performs multiple functions with a single integrated structure: it provides frictional resistance to prevent accidental plunger withdrawal through the skirt, mechanically engages with the plunger through the extensions and ledges, and attaches to the syringe flange. This multi-functionality reduces the need for additional separate components.
Data Source
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AI summary
A backstop for a syringe includes a base having a first surface and an opposing second surface. A skirt extends outwardly from the second surface of the base. An opening extends through the base. The opening is surrounded by the skirt. A first extension extends generally perpendicularly from the second surface at an outer periphery of the base. A second extension extends generally perpendicularly from the second surface at the outer periphery of the base. The second extension is diametrically opposed to the first extension.