Electrodynamic Needle Gripper for Compact High-Force Tissue Handling

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Solution Overview

Problem

Existing needle grippers face challenges in developing a rapid retraction and extension movement with a large holding force in a small installation space while maintaining low energy requirements for gripping tissues or workpieces with low shore hardness and density.

Innovation Solution

The use of an electrodynamic actuator based on the plunger coil principle, coupled with a gear mechanism and needle carriages, allows for efficient movement of needles by deflecting the lifting movement in the direction of the needle carriage travel, enabling a high holding force with low energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a pneumatic cylinder-piston unit is used as the actuator, then the needle gripper can achieve rapid retraction and extension movement, but the installation space increases and energy requirements rise

Engineering Contradiction:
Improveretraction and extension movement speedVSAvoidinstallation space
Core Design Contradiction:
SpeedVSVolume of stationary object

Solution Approach 1:

The patent replaces the pneumatic cylinder-piston unit with an electrodynamic actuator that uses electromagnetic fields to generate motion. This substitution eliminates the need for compressed air systems, reducing installation space while maintaining rapid movement capability through direct electromagnetic force application to the needle carriages.

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

Solution Approach 2:

The patent extracts and eliminates auxiliary pneumatic components (compressors, air lines, reservoirs) by using an electrodynamic actuator that integrates the power generation and motion control functions directly into a compact unit, thereby reducing the overall installation space while preserving speed performance.

Inventive Principle:
Principle #2Taking out (Extraction)

2Force

If a lifting magnet with scissors-like coupling rod system is used, then the holding force is large, but the installation space increases and device complexity rises

Engineering Contradiction:
Improveholding forceVSAvoidinstallation space
Core Design Contradiction:
ForceVSVolume of stationary object

Solution Approach 1:

The patent transitions from a scissors-like mechanical linkage system to a direct linear actuation system where the electrodynamic actuator moves the needle carriages along curved guides. This dimensional simplification reduces the number of mechanical components while maintaining force effectiveness through direct electromagnetic actuation combined with geometric path constraints.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces curved needle carriage guides as intermediary elements that translate the linear motion of the electrodynamic actuator into the desired needle movement paths. These guides replace the complex scissors-like coupling system while maintaining the force transmission efficiency and holding capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Force

If multiple needle carriages are moved with a single electrodynamic actuator via gear mechanism, then the device complexity increases, but the holding force and space efficiency improve

Engineering Contradiction:
Improveholding forceVSAvoidgear mechanism complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent designs the electrodynamic actuator to simultaneously drive multiple needle carriages through a gear mechanism, making the single actuator perform multiple functions. This multi-functionality allows one actuator to control several needles, improving force distribution and space efficiency while the modular gear design keeps complexity manageable.

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

Solution Approach 2:

The patent combines the functions of multiple actuators into a single electrodynamic actuator that drives all needle carriages through a shared gear mechanism. This merging reduces the total number of actuating components, simplifies the overall system, and improves space efficiency while maintaining the ability to generate sufficient holding force across all needles.

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

This configuration enables the needle gripper to effectively grip and hold tissues or workpieces with low shore hardness and density, achieving a high holding force while minimizing energy usage and maintaining a compact design.

Implementation Method 1

Energizing the plunger coil leads to a relative movement between the plunger coil and the pot magnet due to the principle-related Lorenz force

Methodology Applied
Scientific EffectLorenz force: Lorentz Force

Data Source

PatentEP2716585B1Needle gripper with electrodynamic positioning member
Publication Date: 2020.02.12 ZIMMER GUNTHER STEPHAN
  • EP2716585B1 patent drawingFigure 1~2
  • EP2716585B1 patent drawingFigure 3~4
  • EP2716585B1 patent drawingFigure 5~6

AI summary

The needle gripper comprises a housing (10,40) or frame extendible needles (2), where the needles are arranged individually or in groups at one or two oppositely movable needle carriages driven by an actuator over a gear unit. The longitudinal direction of the needles corresponds to the traverse path direction of the corresponding needle carriage. The actuator is an electrodynamic drive. The gear unit deflects the direction of the reciprocating movement of the movable components of the electrodynamic actuator in the traverse path direction of the corresponding needle carriage.