C-FREX

CFRP Lightweight Bipedal Walker Equipment

C-FREX is walking equipment made with CFRP to help people with spinal cord injuries maintain physical faculties.
We are developing equipment with a goal of launching an absolutely new product for people with spinal cord injuries to move around much like a healthy person without using any outside motorized power.

The C-FREX development concept

Applying CFRP to the lower leg socket reduces weight and activates elastic energy.
Knee joint flexion with no power―realization of stretching action
Fulfilling user needs through a sophisticated design not seen in other equipment.

Noritaka Kawashima,
Chief of Neuromuscular Function System Research Laboratory
Research Institute of the National Rehabilitation Center for Persons with Disabilities

HISTORY OF DEVELOPMENT

T1 Model

Realization of the lightness and elastic energy inherent in CFRP

Using the basic structure of ARGO (advanced reciprocating gait orthosis), the current powerless leg orthosis, as the foundation, and adding CFRP material to lighten, strengthen and make more elastic the thigh and lower leg sockets, we address the problems with current equipment, namely its weakness and heaviness.
Activate the elastic energy using the spring plate in the foot’s CFRP plate to get a forward thrust that previous polycarbonates could not produce.
After a walk test, the results expected from CFRP – “It felt like I was touching the ground.”, “The leg movement was smooth.” – became a reality.

N1 Model

Wheelchair and brace-compatible model

The N1 model is compatible with wheelchairs and walking braces. Even if we develop good equipment, if we don’t consider the use environment and accessibility along walking routes, the technology will not lead to benefits for the user.
That’s when we derived a concept model from C-FREX and developed a mobility device that was integrated into the wheelchair.

JEC World 2016 Award
The N1 model received the Innovation Award at JEC (Journals and Exhibitions on Composites) World 2016, the world’s biggest trade fair for the composite material industry, held in Paris in March 2016. A mobility device integrated into a wheelchair was called an innovative invention unparalleled in the world, which led to the award.

JEC World 2016 イノベーションアワード受賞＞

T2 Model

Knee joint flexion – start to develop an extension mechanism and trial of a 3D printer part with continuous carbon fiber

In conventional equipment, because the knee joint is fixed, it is difficult to preserve the clearance on the floor. That sort of restriction on movement can become a physical burden. The T2 model does not use any outside motorized power, and the knee joint can bend and stretch as it aligns to the walking cycle. We aim to develop a product that will allow for movement close to that of a healthy person.

Installation of a 3D Printer with Continuous Carbon Fiber
The specialty of a 3D printer is its low-volume production, and its ability to produce a variety of customized sizes and shapes. Among those printers, the 3D printer with continuous carbon fiber from Mark Forged Inc. makes it possible to make stronger molds, reduce development times, according to independently carried out strength tests and evaluations.

T3 Model

Prototype for walking test with knee joint flexion and weight-loading function

The joints of the hips, knees, and feet in bipedal walking perform flexion and extension movements in each phase of the walking cycle, and the combination has a regular pattern. Utilizing this periodicity, we have developed a “knee joint flexion-extension mechanism” that allows the knee to be held in the extended position during the stance phase and flexion-extension during the swing phase. It is possible to smoothly swing out the legs without using a sensor or battery.

Exhibited at REHACARE 2019
We exhibited for the first time at REHACARE, international trade fair for rehabilitation and care held in Düsseldorf, Germany from September 18 to 21, 2019. About 50,000 people with disabilities to people from the medical, welfare, and nursing industries visited the venue. We received a lot of response from wheelchair users and sales agents in each country.

N2 Model

Final prototype for assumed of product models

Developed the N2 model that follows the design of the function prototype that has been developed so far. This is the final prototype that implements all the conventional concepts of 1) CFRP, 2) flexion and extension of the knee joint, and 3) design. We will continue to test and improve it for practical use.

Exhibited at CES2020
We exhibited C-FREX (N2 model) for the first time at CES2020, a home electronics trade fair event held in Las Vegas, USA from January 7th to 10th, 2020. Approximately 200,000 visitors came to the venue to demonstrate walking by person with spinal cord injury . We received a lot of response from local reporters and research institutions.

Olympic Model

Development concludes with TOKYO 2020 Olympic Torch Relay

The Olympic Model, equipped with C-FREX, now enables users to transition from a wheelchair to a standing position, further enhancing its practicality. This wheelchair was realized through a collaborative effort with RDS Co., Ltd. (President: Yukisato Sugihara), based in Yorii Town. Although this development was pursued with the aim of commercialization, UCHIDA will now conclude its involvement in the project after successfully meeting all required functionalities in the prototype stage.

Kazuhiro Takahashi Lights the Torch
On July 14, 2021, Kazuhiro Takahashi, also known as “Kazu,” a partner in the development of the Olympic Model since its inception, donned the wheelchair and made the Olympic Torch Relay a reality. Due to the impact of the COVID-19 pandemic, the Tokyo metropolitan area’s street relay had to be canceled, and instead, it became a ceremony where Kazuhiro Takahashi lit the torch. With the latest improved C-FREX, Kazu walked with great dignity, taking strong and confident steps, all while being watched by onlookers and stakeholders.

CFRP Lightweight Bipedal Walker Equipment

HISTORY OF DEVELOPMENT

2014 – 2016

Realization of the lightness and elastic energy inherent in CFRP

2015 – 2016

Wheelchair and brace-compatible model

2017 – 2018

Knee joint flexion – start to develop an extension mechanism and trial of a 3D printer part with continuous carbon fiber

2018 – 2019

Prototype for walking test with knee joint flexion and weight-loading function

2019 – 2020

Final prototype for assumed of product models

2021

Development concludes with TOKYO 2020 Olympic Torch Relay