Concentric Driving Units in Prosthetic Elbow Structure

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Solution Overview

Problem

Existing electronic prosthetic hands face challenges in lifting heavy objects due to the large size and noise of high-output driving units, which also lead to overload and damage, and high manufacturing costs.

Innovation Solution

An elbow structure with a hinge-connected upper and lower arm, featuring a first connection part with multiple driving units on a concentric circle and a second connection part with a toothed part, allowing joint movement without a high-output driving unit, minimizing noise and size, and using a spiral spring to compensate for lifting forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a high-output driving unit is mounted on the elbow part to lift heavy objects, then the lifting capability is improved, but the size of the elbow part is enlarged and noise is generated

Engineering Contradiction:

Improvelifting capabilityVSAvoidelbow part size

Core Design Contradiction:

PowerVSVolume of moving object

Solution Approach 1:

The driving unit is divided into multiple small driving units arranged concentrically around the central axis instead of using one large high-output driving unit. Each small driving unit has a gear that engages with the toothed part, distributing the power generation function across multiple segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The driving units are arranged in a concentric circular pattern around the central axis, utilizing radial space in the elbow part. This dimensional arrangement allows multiple driving units to be compactly positioned without increasing the overall elbow volume, as they occupy the circular cross-sectional space efficiently.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Power

If a high-output driving unit is mounted on the elbow part to lift heavy objects, then the lifting capability is improved, but noise is generated causing user stress

Engineering Contradiction:

Improvelifting capabilityVSAvoidnoise

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The single high-output driving unit is segmented into multiple small driving units. Each small driving unit generates less noise individually, and their combined operation provides the necessary lifting power while reducing overall noise levels compared to one large motor.

Inventive Principle:

Principle #1Segmentation

3Volume of moving object

If a mechanical elbow using hinge connection is used without high-power driving unit, then the size is reduced, but the lifting capability is insufficient and the mechanical elbow is easily damaged

Engineering Contradiction:

Improveelbow part sizeVSAvoidlifting capability

Core Design Contradiction:

Volume of moving objectVSPower

Solution Approach 1:

The invention combines the hinge connection mechanism with multiple small driving units. The hinge connection provides the mechanical structure while the multiple driving units with gears provide the necessary power, merging the advantages of both approaches into a unified system.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The pure mechanical hinge connection is enhanced by replacing the need for a single high-power motor with multiple small driving units that use gear mechanisms. This substitution allows the mechanical elbow to maintain structural simplicity while gaining sufficient lifting capability through the gear-based power transmission.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Power

If a high-output driving unit is used to lift heavy objects, then the lifting capability is improved, but the manufacturing cost increases

Engineering Contradiction:

Improvelifting capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

Instead of manufacturing and installing one expensive high-output driving unit, the system uses multiple smaller, less expensive driving units. The cost of multiple small units is lower than a single large unit, while still achieving the required total power output for lifting heavy objects.

Inventive Principle:

Principle #1Segmentation

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

Enables easy gripping and transportation of heavy objects, reduces noise and discomfort, minimizes the risk of overload and damage, and lowers manufacturing costs by eliminating the need for large driving units.

Implementation Method 1

using a spiral spring to compensate for lifting forces

Methodology Applied

Scientific EffectElastic energy storage: Spring

Implementation Method 2

having one ends provided with gears

Methodology Applied

Scientific EffectMechanical advantage through gears: Gear

Data Source

PatentUS12053395B2Elbow structure for electronic artificial arm

Publication Date: 2024.08.06 MAND RO CO LTD

AI summary

Disclosed is an elbow structure, for an electronic artificial arm, which hinge-connects the humeral part and radioulnar part and enables the joint movement of the humeral part and radioulnar part about one central axis. The elbow structure for an electronic artificial arm comprises: a first connection unit of which one end is connected to the radioulnar part and which has inside the other end a plurality of driving portions provided concentrically with and a predetermined distance away from the central axis and each having a gear on one end; and a second connection unit of which one end is connected to the humeral part and which has teeth portions aligned in a circle so as to interlock and rotate with the gears of the plurality of driving portions in the outer direction.