Design of a low-cost, reconfigurable, standing wheelchair with easy and stable sit-stand-sit transition capability

Abstract

Purpose

Assistive devices like Standing Wheelchairs (SWC) have remained out of reach of the economically underprivileged even before the pandemic-induced financial downturn, and more so now. This paper describes the mechanical design of a manual user-actuated SWC that is cost-effective (equivalent of USD 210 in India, ex-factory) and has special features that minimise user effort and accommodates varying body weights (50–110 kg) and dimensions (1.52–1.83 m height).

Methods

The design includes a six-bar mechanism and spring balancing to optimise user effort during operation. The optimised gas spring incorporates adjustability to minimise each user’s force for sit-stand-sit transitions. The handle shape is ergonomically designed using kinematic analysis to provide convenient gripping positions for actuation. The design has been customised based on parametric studies to suit varying body weights.

Results

Overall, the SWC design provides standing functionality with ease of operation, safety locks, customisability, affordability, outdoor mobility and is aesthetically pleasing.

Conclusions

Customisability and the low cost of the device would enhance the accessibility of the SWC to a larger group of eligible users.

Implications for rehabilitation

• Manual user-operated standing wheelchair design using a six-bar mechanism

• Spring balancing used to reduce user effort to self-lift to the standing position

• Kinematic analysis used to determine convenient handle location for user ease

• Customisability for wide range of users to ensure correct posture, optimal effort

• Design refined through multiple iterations using inputs from users and clinicians

• Design commercialised at an affordable cost, making it accessible to a larger population

Keywords:

• Six-bar mechanism
• assistive device
• manual
• user-operated
• standing wheelchair
• spring balancing
• affordable

Acknowledgments

We thank the partnership of Phoenix Medical Systems in the development and commercialization of this device. We gratefully acknowledge the help provided by Christian Medical College and Hospital, Vellore, the Association of People with Disability (APD), Bangalore and St. John’s Hospital, Bangalore for the user testing, and the inputs and contacts enabled by the Spinal Foundation, a pan-India self-help group for users with Spinal Cord Injury. We are grateful to every user who has bravely tried our device and whose feedback has helped us bring it to this stage.

Disclosure statement

The authors report no conflict of interest.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the Wellcome Trust (https://wellcome.org/), UK [Grant number 105863/Z/14/Z] awarded to SS.