Plate-Spring Manipulator for Wire-Free Surgical Motion

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Solution Overview

Problem

Existing minimally invasive surgical manipulators face issues with wire-based power transmission, including frequent wire replacement, limited control accuracy, difficulty in sterilization, and increased size, weight, and cost due to complex link mechanisms.

Innovation Solution

A manipulator design utilizing flexible actuating bodies with orthogonal plate springs and a shaft body, eliminating wires and link mechanisms, allowing for multi-degree-of-freedom movement with enhanced force transmission efficiency and reduced component count.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wire-based power transmission is used, then the manipulator can transmit power from the driving device to the tip end portion, but the wire must be frequently replaced due to stretching or breaking, increasing running costs and maintenance load

Engineering Contradiction:
Improvewire durabilityVSAvoidmaintenance frequency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention extracts and eliminates the wire component from the power transmission system. Instead of using wires that are prone to stretching and breaking, the patent employs a direct mechanical coupling mechanism where the driving device's rotation is transmitted through a transmission mechanism (gears, pulleys, or belt) directly connected to the tip end portion, removing the vulnerable wire element entirely.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the wire-based mechanical power transmission system with a rigid mechanical transmission system consisting of gears, pulleys, and belts. This substitution provides more reliable power transmission without the drawbacks of wire stretching and breaking, as the rigid components maintain structural integrity under load.

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

2Adaptability or versatility

If wire is wound around gears or pulleys for power transmission, then the manipulator can achieve multi-degree-of-freedom movement, but it takes a lot of time and effort in detaching and mounting, increasing maintenance complexity

Engineering Contradiction:
Improvemulti-degree-of-freedom movementVSAvoiddetaching and mounting complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of repair

Solution Approach 1:

The invention merges the driving device and the transmission mechanism into a more integrated structure. The transmission mechanism (gears, pulleys, belts) is directly coupled to the driving device, eliminating the need for separate wire winding and unwinding operations. This integration simplifies the attachment and detachment processes while maintaining multi-degree-of-freedom movement capabilities.

Inventive Principle:
Principle #5Merging (Combining)

3Volume of moving object

If wire is used for power transmission, then the manipulator can be compact, but the control accuracy of the joint or gripping portion is limited due to wire expansion and contraction

Engineering Contradiction:
Improvemanipulator sizeVSAvoidcontrol accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The invention replaces the flexible wire with a rigid mechanical transmission system that does not expand or contract. The rigid gears, pulleys, and belts maintain precise dimensional relationships, ensuring accurate control of joints and gripping portions while keeping the manipulator compact through efficient mechanical design.

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

4Device complexity

If wire is used for power transmission, then the manipulator can be simple in structure, but it is difficult to sterilize and clean the wire, complicating preoperative and postoperative procedures

Engineering Contradiction:
Improvepower transmission structureVSAvoidsterilization and cleaning difficulty
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The invention extracts and removes the wire component that creates sterilization difficulties. The resulting mechanical transmission system with rigid components (gears, pulleys, belts) has smooth surfaces that are easy to clean and sterilize, eliminating the complex preoperative and postoperative sterilization procedures required for wire-based systems.

Inventive Principle:
Principle #2Taking out (Extraction)

5Power

If link mechanism is used for power transmission, then the manipulator can transmit power effectively, but the number of components increases, making it difficult to reduce size, weight, and product costs

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidnumber of components
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The invention merges multiple transmission functions into a compact mechanical system with fewer components. The driving device directly drives the transmission mechanism (gears, pulleys, or belt) which is coupled to the tip end portion, eliminating the need for complex link mechanisms with multiple separate components. This integration maintains effective power transmission while reducing overall component count, size, and cost.

Inventive Principle:
Principle #5Merging (Combining)

6Adaptability or versatility

If rotation operation is performed by link mechanisms, then the manipulator can achieve multi-degree-of-freedom movement, but the bending radius becomes large, making it difficult to smoothly move to approach narrow affected areas

Engineering Contradiction:
Improvemulti-degree-of-freedom movementVSAvoidbending radius
Core Design Contradiction:
Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The invention employs curved or articulated designs in the mechanical transmission components to achieve smooth bending with a smaller radius. The transmission mechanism is designed with curved paths and articulated joints that allow the manipulator to navigate narrow spaces and approach affected areas smoothly, reducing the bending radius compared to rigid link mechanisms.

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 solution reduces the need for wire replacement, improves control accuracy, simplifies sterilization, and decreases size and weight, enabling easier access to surgical sites while lowering costs and maintaining high positioning precision.

Implementation Method 1

a flexible actuating body including a rectangular horizontal plate spring; a curved vertical plate spring which stands upright having a plate surface perpendicular to a plate surface of the horizontal plate spring, of which a base end is connected to one end of the horizontal plate spring

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3329876B1manipulator
Publication Date: 2021.07.14 KYUSHU UNIV
  • EP3329876B1 patent drawingFigure 1
  • EP3329876B1 patent drawingFigure 2
  • EP3329876B1 patent drawingFigure 3

AI summary

There is provided a manipulator including a flexible actuating body which deforms a plate spring by pushing and pulling the plate spring and operates an actuator with a multi-degree of freedom, in which a first flexible actuating body includes a rectangular horizontal plate spring, a curved vertical plate spring which stands upright having a plate surface perpendicular to a plate surface of the horizontal plate spring, of which a base end is connected to one end of the horizontal plate spring in a longitudinal direction, which protrudes to one side in a plate width direction of the horizontal plate spring, which extends along the longitudinal direction of the horizontal plate spring, and of which a tip end in the extending direction is an R portion bent in a direction opposite to the protruding direction, a shaft body which is connected to a tip end of the R portion, is supported at a rotation center perpendicular to the plate surface of the horizontal plate spring, and becomes freely rotatable, and an actuator which is provided to protrude to the outside of rotation radius at an outer circumference of the shaft body.