Syringe Piston Surface Structure Friction Reduction

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Solution Overview

Problem

Existing syringe components face challenges in reducing friction between the cylinder and piston or seal without causing pharmaceutically undesirable interactions, as materials like silicone and PTFE can react with certain active ingredients and compromise sealing tightness.

Innovation Solution

A surface structure with specific geometric features, such as linear indentations, elevations, and patterns on the syringe components, is introduced to reduce friction without adding additional materials, ensuring effective sealing and minimizing interactions with active ingredients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If an additional layer with friction-reducing properties (such as silicone layer or PTFE layer) is provided between the piston and cylinder, then friction is reduced, but pharmaceutically undesirable interactions occur between the layer material and the active ingredient

Engineering Contradiction:
ImprovefrictionVSAvoidpharmaceutically undesirable interactions
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the harmful additional material layer from the system and replaces it with a geometric surface structure on the piston rod. The surface structure consists of longitudinal grooves and/or transverse grooves that reduce friction through geometry alone, eliminating the risk of pharmaceutical interactions while maintaining the friction-reducing function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The surface structure acts as an intermediary between the piston rod and the cylinder wall. Instead of using a material layer as an intermediary, the invention uses a geometric surface structure with grooves that create a lubricating effect through the geometry itself, reducing friction without introducing any material that could interact with the active ingredient.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If PTFE layer is used to reduce friction, then friction is reduced, but the seal is compromised because PTFE is relatively hard

Engineering Contradiction:
ImprovefrictionVSAvoidsealing tightness
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The invention replaces the material-based friction reduction system (PTFE layer) with a geometry-based system (surface structure with grooves). The grooves create a mechanical lubricating effect through their shape and arrangement, reducing friction without relying on material properties that compromise sealing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The surface structure applies local quality variations through grooves at specific locations on the piston rod surface. The grooves are strategically positioned and dimensioned to provide friction reduction exactly where needed, while the rest of the piston rod surface maintains its sealing contact with the cylinder wall.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If a surface structure with grooves is formed on the piston rod, then friction is reduced without additional materials, but the manufacturing complexity increases

Engineering Contradiction:
Improvepharmaceutically undesirable interactionsVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The invention merges the friction-reducing function with the existing piston rod manufacturing process. The surface structure with grooves is integrated into the piston rod as a single component, combining the structural function of the piston rod with the friction-reducing function in one manufacturing step, rather than adding a separate material layer.

Inventive Principle:
Principle #5Merging (Combining)

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 surface structure effectively reduces friction between syringe components, preventing jerky movements and ensuring precise dosing while avoiding pharmaceutically undesirable effects, thus enhancing the administration and sampling processes.

Implementation Method 1

a surface structure formed by shaping a region (4) of the component (1, 2, 3), wherein the surface structure (5) is designed to reduce friction within the syringe due to its shape

Methodology Applied
Scientific EffectFriction reduction through geometric surface structure: Friction

Data Source

PatentEP3248635B1Component for a syringe and syringe
Publication Date: 2020.01.29 GERRESHEIMER REGENSBURGH GMBH
  • EP3248635B1 patent drawingFigure 1A~1B
  • EP3248635B1 patent drawingFigure 2~4
  • EP3248635B1 patent drawingFigure 5~8

AI summary

A component (1, 2, 3) for a syringe (101, 102) is disclosed, which has a structure (5) formed that, due to its shape, reduces friction in the syringe (101, 102). The component can, in particular, be a cylinder (1), a piston (2), or a seal (3) for the syringe (101, 102). The structure (5) consists, for example, of elevations or depressions having a linear, point-like, elliptical, or polygonal plan. A syringe (101, 102) having at least one such component (1, 2, 3) is also disclosed. The use of a component (1, 2, 3) with a friction-reducing structure (5) eliminates the need for an additional friction-reducing coating made of, for example, silicone, which can lead to undesirable effects on the drug administered with the syringe.