Rotatable Wave Washer Spring for Adjustable Energy Storage

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Solution Overview

Problem

In orthopedic devices such as orthoses and prostheses, there is a challenge in adapting energy storage springs to varying energy requirements and operating states due to limited installation space, often necessitating non-adjustable springs that are selected based on specific purposes and patient needs.

Innovation Solution

A spring device comprising at least two wave washers made of dimensionally stable material with a spring washer arranged between them, allowing for continuous adjustment through rotational mounting, enabling variable stiffness and energy storage by rotating the wave washers relative to each other, and driven by a motor for precise control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a non-adjustable storage spring is used, then the device complexity is reduced, but the adaptability to different energy requirements and operating states is worsened

Engineering Contradiction:
Improvespring device complexityVSAvoidadaptability to energy requirements
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The spring device employs wave washers that can rotate relative to each other, dynamically changing the effective number of active waves in the spring. This rotational adjustment mechanism allows the spring stiffness and energy storage capacity to be varied continuously, transforming a static spring system into a dynamic one that adapts to different operating conditions while maintaining relatively simple device architecture.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the physical parameter of spring stiffness by altering the geometric configuration of the wave washers. By rotating the wave washers to different angular positions, the effective number of active waves changes, which directly modifies the spring constant and energy storage capacity. This parameter change approach enables adaptability without requiring multiple different spring components.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the spring stroke is increased to store more energy, then the energy storage capacity is improved, but the construction volume increases

Engineering Contradiction:
Improveenergy storage capacityVSAvoidconstruction volume
Core Design Contradiction:
Quantity of substanceVSVolume of moving object

Solution Approach 1:

The invention transitions from a linear spring design to a rotational/dimensional design using wave washers. Instead of increasing the axial length (one dimension) to store more energy, the system uses the rotational dimension of the wave washers to control the number of active spring waves. This allows energy storage capacity to be adjusted without proportionally increasing the construction volume, as the compact wave washer structure provides high energy density in a small space.

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

Solution Approach 2:

The wave washers are arranged in a nested or stacked configuration where multiple wave structures are contained within a compact axial space. This nesting allows the spring device to achieve significant energy storage capacity through the cumulative effect of multiple wave waves without requiring a proportional increase in overall device volume, as the waves are efficiently packed in a three-dimensional arrangement.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of operation

If a motor-driven adjustment device is added, then the ease of operation for adjusting spring parameters is improved, but the device complexity increases

Engineering Contradiction:
Improveadjustment easeVSAvoidspring device complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention replaces manual mechanical adjustment with an automated motor-driven system. The motor can be controlled electronically to rotate the wave washers to predetermined positions, enabling precise and repeatable adjustment of spring parameters without requiring manual intervention. This substitution of mechanical manual operation with automated motor control significantly improves ease of operation, particularly for applications requiring frequent or precise adjustments.

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

Solution Approach 2:

The motor-driven adjustment device serves multiple functions: it can adjust the spring stiffness, control the energy storage capacity, and potentially monitor or sense the spring state. This multi-functionality consolidates several potential adjustment mechanisms into a single universal device, reducing overall system complexity despite the addition of the motor component.

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

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 solution allows for a compact design with adjustable stiffness and energy storage capacity, accommodating different patient needs and activity levels without requiring additional compensation volume, ensuring efficient energy absorption and release in orthopedic applications.

Implementation Method 1

a spring washer (20) arranged between these wave washers, the wave washers being mounted so that they can rotate relative to one another

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3926202B1Spring mechanism and hydraulic actuator
Publication Date: 2023.10.25 OTTO BOCK HEALTHCARE PROD GMBH
  • EP3926202B1 patent drawingFigure 1
  • EP3926202B1 patent drawingFigure 2
  • EP3926202B1 patent drawingFigure 3

AI summary

The invention relates to a spring device with at least two wave disks (11, 12, 13), with at least one spring disk (20) arranged between the wave disks (11, 12, 13), wherein the wave disks (11, 12, 13) are mounted to be rotatable relative to each other, wherein at least one wave disk (11, 12, 13) is coupled to a motor-driven adjusting device (40).