Variable Spring Mechanism for Assistive Walker Seat

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Solution Overview

Problem

Conventional assistive walker devices lack integrated seating accommodations, making it tiresome for users to transition from sitting to standing, especially for individuals with weak limbs or geriatric users, as they require frequent assistance and disrupt therapy sessions.

Innovation Solution

A seat device integrated with an assistive walker, featuring a folding seat platform hinged to a frame with a spring mechanism that biases the seat towards its folded position, reducing the effort required for users to stand up, by varying the overall spring constant based on the seat's position, providing support during transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional assistive walker device is used without integrated seating, then the device structure remains simple, but the user has to leave the walker to rest which disrupts therapy and requires frequent transitions

Engineering Contradiction:
Improvetherapy efficiencyVSAvoiddevice structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the seating function with the walker device by integrating a seat platform that can be folded into the walker's frame structure. This merging allows users to rest without leaving the device, eliminating therapy disruptions while maintaining a relatively compact overall structure when the seat is folded.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The seat platform is designed to be dynamically foldable between a deployed seating position and a retracted storage position. This dynamic capability allows the device to adapt between providing seating support and maintaining a simple walker structure, resolving the contradiction between functionality and structural simplicity.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If a seat is integrated into the assistive walker device, then the user can rest without leaving the device, but the device complexity increases

Engineering Contradiction:
Improveease of transitioning from sitting to standingVSAvoiddevice structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The spring mechanism is designed to automatically provide upward biasing force to assist the user's transition from sitting to standing without requiring external assistance. The system serves itself by using the user's downward sitting action to compress the spring, which then automatically releases energy to help lift the user back up, reducing the need for complex mechanical assistance systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The spring mechanism acts as a counterweight system by providing an upward biasing force that opposes the user's body weight during the transition from sitting to standing. This reduces the net force the user must generate, making the transition easier while avoiding the need for complex motorized or hydraulic lift systems.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Force

If a spring mechanism with constant spring constant is used, then the mechanism is simple, but the effort required for standing up remains high throughout the entire motion

Engineering Contradiction:
Improvespring forceVSAvoidspring mechanism structure
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The spring mechanism is segmented into multiple individual springs connected in series, each with different spring constants. This segmentation allows each spring to contribute differently to the overall force profile, creating a variable effective spring constant that provides higher force when needed (during standing transition) and lower force during other phases, optimizing assistance throughout the motion range.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different springs within the mechanism have different local qualities (spring constants) tailored to specific phases of the sitting-standing transition. The arrangement ensures that stiffer springs engage when maximum force is needed for lifting, while more compliant springs handle the initial contact and later phases, creating a non-uniform force distribution optimized for the transition dynamics.

Inventive Principle:
Principle #3Local quality

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

Enhances therapy efficiency by allowing users to rest without leaving the device and reduces the effort needed to stand, making therapy less tiresome and more intense by utilizing a stronger spring force in the seated position and a reduced force in the standing position.

Implementation Method 1

a spring mechanism with a variable overall spring constant, via which the seat platform is connected to the frame in a manner so as to be biased towards its folded position

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The (respective) spring mechanism has, e.g., a variable overall spring constant (i.e. different spring constants at different positions of the seat platform during folding/unfolding of the seat platform)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3078363B1Seat device and assistive walker device comprising the seat device
Publication Date: 2020.02.19 XENTIQ PARTNERS PTE LTD
  • EP3078363B1 patent drawingFigure 1
  • EP3078363B1 patent drawingFigure 2
  • EP3078363B1 patent drawingFigure 3

AI summary

A seat device is provided, comprising: a frame, a seat platform which is hinged to the frame so as to be pivotable between a completely folded position and a completely unfolded position, in which a user is allowed to seat thereon, and a spring mechanism with a variable overall spring constant, via which the seat platform is connected to the frame in a manner so as to be biased towards its folded position, thereby reducing an effort required by the user, who seats on the seat platform, for standing up therefrom, wherein the spring mechanism comprises a plurality of spring devices, each of which has an at least substantially constant spring characteristic which is at least substantially defined by a corresponding spring constant, and which are connected to each other in series, wherein the spring mechanism is provided such that, when the seat platform is at least substantially in its completely folded position, the variable overall spring constant is lower than in the case when the seat platform is at least substantially in its completely unfolded position, and wherein, when the seat platform is in its completely unfolded position, the overall spring constant is defined by the spring constants of only a fraction of the plurality of spring devices.