Bone Cement Dough Mixing With Staged Monomer Transfer

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Solution Overview

Problem

Existing bone cement preparation devices are susceptible to operating errors due to simultaneous fluid opening and conveying of monomer liquid, leading to incomplete mixing and undesirable compositions, and there is a need for simpler, safer, and more reliable preparation methods.

Innovation Solution

A device with a transfer unit and mixing unit that separates the fluid opening and conveying steps through distinct configurations, using a delivery piston connected to an opening means to ensure complete monomer liquid flow before transfer, minimizing manual effort and reducing the risk of errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the monomer liquid container is opened and the conveying piston is displaced simultaneously, then the preparation process is simplified and faster, but operating errors occur due to incomplete pumping of monomer fluid

Engineering Contradiction:
Improvepreparation speedVSAvoidmixing completeness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The device segments the opening and conveying operations into distinct temporal phases. The conveying piston is designed to be displacement-limited during the opening phase, allowing the monomer liquid container to open completely before conveying begins. This segmentation ensures complete fluid transfer while maintaining operational simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The device performs preliminary action by limiting the conveying piston's displacement during the opening phase. The piston is designed with a stop or mechanical constraint that prevents full conveying displacement until the monomer liquid container is fully opened. This preliminary restriction ensures complete fluid transfer before mixing occurs.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If the conveying piston is displaced fully during opening, then complete monomer liquid transfer is achieved, but the mixing ratio becomes incorrect due to premature pumping

Engineering Contradiction:
Improvemonomer liquid transfer completenessVSAvoidmixing ratio accuracy
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The conveying piston's displacement is made dynamic rather than fixed. During the opening phase, the piston can move only a limited distance (first displacement limit). After the monomer liquid container opens, the piston can displace further (second displacement limit). This dynamic displacement control ensures complete liquid transfer while preventing premature pumping that would disrupt mixing ratios.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The device changes the displacement parameter of the conveying piston based on the operational phase. The piston is designed with different displacement limits for different phases: a first limit during opening and a second, greater limit after opening. This parameter change ensures accurate monomer liquid transfer quantity while maintaining correct mixing ratios.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If additional tools are used to open the monomer liquid container, then reliable opening is achieved, but the device complexity increases

Engineering Contradiction:
Improveopening reliabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The conveying piston is designed with multi-functionality. It serves both as the conveying mechanism for monomer liquid and as the opening mechanism for the monomer liquid container. By integrating the opening function into the piston, the device eliminates the need for separate opening tools while maintaining reliable opening through the piston's mechanical action.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The device merges the opening and conveying functions into a single component system. The conveying piston simultaneously performs the opening action and the conveying action, eliminating the need for separate tools. This merging reduces device complexity while maintaining opening reliability through the integrated mechanical design.

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 device ensures reliable and efficient preparation of bone cement dough with precise mixing ratios by separating the opening and conveying processes, enhancing safety and reducing the likelihood of incomplete mixing.

Implementation Method 1

a delivery piston (420) that can be moved axially in the hollow cylinder (410)

Methodology Applied
Scientific EffectPiston displacement: Displacement

Implementation Method 2

an axial displacement of the feed piston from a first position into a second position pushes the opening means against the monomer liquid container

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP4616933A1Device and method for providing a bone cement dough
Publication Date: 2025.09.17 HERAEUS MEDICAL GMBH
  • EP4616933A1 patent drawingFigure 1
  • EP4616933A1 patent drawingFigure 2
  • EP4616933A1 patent drawingFigure 3

AI summary

Device (100, 100') for providing a bone cement dough (500) from two starting components, comprising a mixing unit (200, 200') with an interior space (210, 210') in which a bone cement powder (510, 510') is stored or can be stored as the first starting component, a reservoir (300, 300') with a reservoir container (310, 310') in which at least one fluid-conducting closed monomer liquid container (320, 320') filled with a monomer liquid (520, 520') is stored or can be stored as the second starting component, a transfer unit (400, 400') comprising a hollow cylinder (410, 410') and a delivery piston (420, 420') which can be displaced axially in the hollow cylinder (410, 410'), wherein the mixing unit (200, 200') and the reservoir (300, 300') are or can be connected to one another in a fluid-conducting manner via the hollow cylinder (410, 410'), wherein the monomer liquid container (320, 320') in the device (100, 100') can be opened in such a way that the monomer liquid (520,520') from the reservoir (300, 300') into the hollow cylinder (410, 410') via a passage (330, 330') and can be conveyed from the hollow cylinder (410, 410') into the interior (210, 210') by axial displacement of the delivery piston (420, 420') in the hollow cylinder (410, 410'), characterized in that in a first configuration of the device (100, 100'), the delivery piston (420, 420') is connected to an opening means (430, 430'), so that axial displacement of the delivery piston (420, 420') from a first position to a second position pushes the opening means (430, 430') against the monomer liquid container (320, 320'), so that the monomer liquid container (320, 320') can be opened in a fluid-conducting manner by the opening means (430, 430') and the monomer liquid (520, 520') can flow from the reservoir (300, 300') via the passage (330, 330') into the hollow cylinder (410, 410'), and that in a second configuration of the device (100,100') the delivery piston (420, 420') is separated from the opening means (430, 430'), so that the monomer liquid (520, 520') can be delivered from the hollow cylinder (410, 410') into the interior (210, 210') by a continued axial displacement of the delivery piston (420, 420') from the second position towards a third position.