Coated Syringe Piston Stopper With Deformation Profile for Easy Sliding
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Solution Overview
Problem
Existing piston stoppers for syringes face challenges in ensuring a tight seal while minimizing material interactions with dispensed fluids, particularly due to coatings that stiffen the plunger stopper, complicating assembly and actuation, and manufacturing is hindered by complex thread designs.
Innovation Solution
A piston stopper design featuring a cylindrical body with a coated front wall and radial deformation profiles, along with a discontinuous internal thread, facilitates insertion and actuation while maintaining a seal, and simplifies manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a coating (e.g., ETFE film) is applied to the front surface of the plunger stopper to limit interaction with the fluid, then the risk of interactions between the plunger stopper material and the fluid is reduced, but the coating stiffens the front surface, making assembly and movement of the plunger stopper within the syringe body more difficult
Solution Approach 1:
The front surface of the plunger stopper is divided into two distinct zones: a coated zone (front face) that provides chemical inertness and a non-coated zone (cylindrical peripheral surface) that maintains flexibility for assembly. This segmentation allows each zone to fulfill its specific function without compromising the other.
Solution Approach 2:
The coating is applied selectively only to the front face of the plunger stopper where fluid contact occurs during storage and dispensing, while leaving the cylindrical peripheral surface uncoated. This local application ensures the coated area provides chemical resistance while the uncoated area maintains the elasticity needed for easy assembly and movement.
2Reliability
If a thread is created on the internal surface of the piston plug to mesh with the piston rod, then interaction between the piston plug and actuating element is achieved, but the significant undercuts in the mold required to create the thread complicate the demolding process
Solution Approach 1:
Instead of creating internal threads directly in the mold cavity (which requires complex undercut removal), the thread is formed on the external surface of the piston rod. This inversion simplifies the mold design, allowing for easier demolding while still achieving the required threaded interaction between the piston rod and piston plug.
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 design ensures reliable sealing and easy assembly/actuation, reduces assembly complexity, and lowers manufacturing costs by minimizing friction and simplifying the molding process.
Implementation Method 1
a front wall having a front axial external surface provided with a coating, advantageously an ethylene tetrafluoroethylene (ETFE) film
Implementation Method 2
said front axial external surface of said front wall having a deformation profile arranged radially inside said sealing profile of said front wall, said deformation profile being adapted to deform radially to facilitate the insertion and/or sliding of said piston stopper into a syringe body
Data Source
Figure 1~3
Figure 4~8
Figure 9~10
AI summary
The invention relates to a plunger-plug (10) made of an elastomer in particular, which comprises a cylindrical body (11) having a front axial side closed by a front wall (13), said hollow cylindrical body (11) comprising an external surface provided with at least one sealing profile (110), said front wall (13) comprising a front axial external surface (131) provided with a coating (135), advantageously a film made of ethylene tetrafluoroethylene (ETFE), said front wall (13) comprising, on the radially external edge thereof, a sealing profile (130), said front axial external surface (131) of said front wall (13) comprising a deformation profile (133) arranged radially inside said sealing profile (130) of said front wall (13), said deformation profile (133) being suitable for undergoing radial deformation in order to facilitate the insertion and/or the sliding of said plunger-plug (10) in a syringe body (1).