EN2313 – Engenharia de Reabilitação

WheelchairsChapter 8, An introduction to rehabilitation engineering

Agenda

► Why do we need to know about

wheelchairs?

► Types of wheelchair

► Manual Wheelchairs

► Basic components and important characteristics

► Wheelchair propulsion biomechanics

► SmartWheel

► Standards By: Kristy A. Godoy JaimesBiomedical Engineer

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

► An estimated 1% of the world's population, or just over 74 million people, need a

wheelchair. [1]

► In 2003, 20 million people requiring a wheelchair for mobility did not have one. [1]

► Around 14 million Brazilians suffer some kind of motor disability, and 40% of those need a

wheelchair (around 5 million people). [2]

Motivation

[1] http://www.who.int/disabilities/publications/technology/wheelchairguidelines/en/[2] COSTA H. Modelagem e simulação da propulsão de cadeiras de rodas manuais. Dissertação. 2015. São Paulo [3] http://www.freewheelchairmission.org/whywheelchairs

Wheelchairs provide mobility, and mobility changes everything;

Mobility means independence, the ability to participate in society and earn a living;

It means dignity, leaving behind the days of living on the ground. [3]

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

WheelchairsElectric power wheelchairs (EPW)

Power-assisted wheelchairs

Manual wheelchairs

Indicated for individuals:

• With severe sensory motor impairments:

• High level tetraplegia.

• Advance multiple sclerosis.

• Severe cerebral palsy.

Advantages

• Technological advances of programmability , special seating systems and

integrated control units = wider potential users

• SmartDrive

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Manual wheelchair

Principal conditions and abilities

• Upper body strength.

• Function.

• Endurance, resistance.

• Self-propeled

Some pathological conditions:

• Spinal cord injury at 1st thoracic level or below and some at

6th or 7th cervical level injury

• Spina bifida

• Multiple sclerosis, early stages

• Lower limb amputation

• Postpolio affecting lower extremity

• Arthritis

• Stroke

• Age

• Cardiopulmonary disease

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Basic structural components

Wheelchair should be designed specifically.

• Standard wheelchairs not for long-term use.

• Heavy duty or bariatric wheelchairs overweight

individuals (136-454 kg).

• Children.

• Sports (lightweight, maneuverable, adjusting the

axle position and camber angles).

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Manual wheelchair assessment

• List of Problems and Aims, as identified by the patient

• Medical

• Social/Functional/Environmental

• Transfers

• Physical Measurements

• Postural Assessment

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Manual wheelchair assessment

• Postural Assessment

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Basic structural components

• Frame: chrome, aluminum, steel tubing,

titanium, besides stainless steel. Affects the

overall weight, durability, transportability and

storage.

• Seat height: leg length, footrest high to avoid

obstacles, the right height for tables, counters

and sinks height

• Seat depth: support for thighs

• Seat width

• Back height: depends on postural support,

affects the range of motion for propulsion.

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

• Seat and back angles

• Armrest and footrest:

• Letting the arm lie parallel to the ground.

• Can affect neck and shoulder.

• Affects the width of the wheelchair.

• Footrest can be adjustable or removable.

• Wheels and tires:

• Typically 2 large rear wheels and 2 small front

wheels (casters).

• Casters 5 to 20 cm in diameter

• Rear wheels 60.96 cm (24”), spoked

Basic structural components

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Basic structural components

http://www.wheelchairnet.org/wcn_wcu/SlideLectures/MS/5WCBiomech.pdf

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Basic structural components

• Rear wheel camber:

• Inclination of the rear wheel, where the

upper part is closer, and, thus, the

bottom part is further from the midline.

• Up to 8° of camber.

• >8° of camber in sports wheelchairs.

• Affects wheelchair width.

http://www.streetsie.com/manual-wheelchair-design-production/

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Basic structural components

• Rear axle position:

• Can be adjusted Horizontally and vertically.

• Weight distribution between rear wheels and casters.

• If more weight proportion falls into the caster the

greater the rolling resistance.

• If rear wheels are in a rearward position, the length of the

wheelbase is greater and the turning radius is increased.

• If the rear wheels are in rearward position, is less likely to

tip backwards.

• Lowering the seat height improves stability, but it affects

the arms abduction.

http://www.clinical-corner.com/2014/01/centre-of-gravity-and-manual-wheelchairs/

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Basic structural components

http://www.wheelchairnet.org/wcn_wcu/SlideLectures/MS/5WCBiomech.pdf

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Stability

http://web.mit.edu/sp.784/www/DOCUMENTS/Wheelchair%20Manual-Final.pdf

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Wheelchair propulsion

• Kinematics:

• Main interest: arms and trunk.

• Kinetics:

• Forces and moments applied to the pushrim.

• Joint forces and moments.

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

http://ebm.ufabc.edu.br/wp-content/uploads/2014/06/NBR-06440.pdf

ABNTNBR ISO 6440

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

ABNT NBR 9050

Accessibility to buildings, furniture,

spaces and urban facilities

EN2313 – Engenharia de Reabilitação 2-2016 - Wheelchairs

Obrigado!