Polygonal Piston Smearing Module for Banknote Cassette Space Optimization

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Solution Overview

Problem

Conventional smearing modules with circular pistons are inefficient in space utilization within parallelepipedic banknote cassettes, leading to wasted space and reduced effectiveness due to mismatched geometry between the piston and the cassette, preventing the storage of larger banknotes and inefficient smearing.

Innovation Solution

A smearing module with a piston having an oblong transverse section and a shape complementary to the chamber, featuring a polygonal contour with rounded corners, and a gas generator that stabilizes the piston using a calming cavity and balanced orifice arrangement to ensure efficient smearing substance distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a circular piston is used in the smearing module, then the piston can move smoothly within the chamber, but the module occupies excessive space and cannot efficiently utilize the parallelepipedic cassette volume

Engineering Contradiction:
Improvespace utilizationVSAvoidpiston shape complexity
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent applies asymmetry by changing the piston cross-section from a circular shape to a polygonal shape (rectangular, square, or other polygons) that matches the parallelepipedic geometry of the cassette. This asymmetric adaptation eliminates wasted space between the circular piston and the rectangular chamber walls, optimizing volume utilization while maintaining manufacturing feasibility through standard machining processes.

Inventive Principle:
Principle #4Asymmetry

2Length of stationary object

If the piston chamber housing is enlarged to accommodate a circular piston, then the piston can function properly, but the overall module size increases and prevents storage of larger banknotes

Engineering Contradiction:
Improvemodule heightVSAvoidsmearing effectiveness
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent changes the geometric parameters of the piston from a circular cross-section to a polygonal cross-section with rounded corners. This parameter change allows the piston to fit tightly within the rectangular chamber boundaries, reducing the required chamber dimensions and overall module height while maintaining reliable smearing function through the rounded corners that ensure proper sealing and movement.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If a circular piston is used, then the design is simple and easy to manufacture, but wasted space creates empty slots that reduce smearing effectiveness

Engineering Contradiction:
Improvesmearing efficiencyVSAvoidchamber volume
Core Design Contradiction:
ProductivityVSVolume of stationary object

Solution Approach 1:

The patent applies asymmetry by changing the piston cross-section from a circular shape to a polygonal shape (rectangular, square, or other polygons) that matches the parallelepipedic geometry of the cassette. This asymmetric adaptation eliminates wasted space between the circular piston and the rectangular chamber walls, optimizing volume utilization while maintaining manufacturing feasibility through standard machining processes.

Inventive Principle:
Principle #4Asymmetry

4Volume of moving object

If the module is compacted to reduce size, then more banknotes can be stored, but the piston may become unstable and difficult to control during movement

Engineering Contradiction:
Improvemodule compactnessVSAvoidpiston stability
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies curvature by incorporating rounded corners on the polygonal piston cross-section. These rounded corners serve multiple functions: they maintain the compact polygonal shape for space efficiency while eliminating stress concentration points that would cause instability, and they facilitate smooth movement within the chamber by reducing friction at the corners. This curved modification to the polygonal shape ensures piston stability during compact module operation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 module achieves a 20% space savings, allowing for the accommodation of larger banknotes and improved smearing efficiency by optimizing the geometric integration and stability of the piston within the cassette.

Implementation Method 1

a gas generator capable of generating a gas flow to push the piston

Methodology Applied
Scientific EffectGas generation: Combustion

Implementation Method 2

a piston capable of moving in a sealed manner thanks to the placement of a seal

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP2525037B1Module for smudging objects to be secured, having a piston with a substantially polygonal cross-section
Publication Date: 2019.04.17 OBERTHUR CASH PROTECTION
  • EP2525037B1 patent drawingFigure 1
  • EP2525037B1 patent drawingFigure 2
  • EP2525037B1 patent drawingFigure 3~5

AI summary

The module has a chamber (11) filled with smudging substance i.e. ink. A piston (12) displaces the chamber. A gas generator (13) generates flow of gas to push the piston for ejection of the substance from the chamber. The piston includes a section whose contour is a polygon with rounded corners. A constant portion of the chamber has a shape complementary to that of the piston. An interface piece (17) forms an interface between the gas generator and the chamber. The interface piece includes a plenum cavity to tranquillize the gas before injected into the chamber.