You Picked the Right Frame; Don’t Stop There!

Shari Schubert, ATS

 

 

 

Program Description

·        Picking the right manual wheelchair frame is only half the battle.

Maximizing mobility comes from adjusting the axle position and choosing the right wheel/caster packages. 

·        It’s not as straight forward as it seems!

 

Objectives:

·        Understanding where the axle should be placed to MAXIMIZE propulsion.

·        Choosing the right rear wheel & tire to MAXIMIZE performance.

·        Knowing the importance of caster set-up and options to MAXIMIZE maneuverability.

 

 

 

Manual Frames

 

So you’ve picked the right frame?

 

Manual Frame Styles

·        Folding

·        Rigid

·        Tilt

·        Recline

 

 

 

Folding VS. Rigid Frames

Considerations:

·        Lifestyle

·        Chair weight

·        Rider weight

·        Method of transportation          

·        Durability

·        Growth potential

·        Accommodation of progressive conditions

·        Efficiency

 

Folding Frames

Benefits

·        Easily folded for transportation

·        Can be grown

·        Modular frames

Negatives

·        Heavier than rigid

·        Less energy efficient

·        Less durable

 

Rigid Frames

Benefits

·        Increased durability

·        Increased energy efficiency

·        More responsive

·        Lighter weight

Negatives

·        Limited growth and ability to meet changes in function

 

Tilt-in-Space

·        Change of position in space while maintaining seat to back angle

-          Pressure / load distribution

-          Tone control

-          Stable seating

-          Visual orientation

-          Function

-          Rest

 

 

 

Recliner

·        Open seat to back angle

-          Pressure/load distribution

-          Bowel / Bladder care

-          Rest

 

Manual Frames

·               So you’ve picked the right frame?

·               Guess what?

·         You’re less than half way done.

 

 

 

Why Do We Adjust a Wheelchair?

 

To maximize the function of the user.

 

Wheelchair Adjustments Can Effect ...

 

·        Posture

·        Propulsion

·        Performance

 

 

Propulsion

·        Seat to floor height

·        Center of gravity (COG)

·        Rear wheel camber

·        Wheel base width

 

Seat To Floor Height

A proper STFH:

·        Transfers

·        Wheelchair propulsion via wheels or w/ feet

·        Stability

            - Fixed tilt in space

·        Environment

·        Work surfaces/ counters

·        Tables

 

 

 

Center of Gravity

·        The COG adjustment changes the relationship of the body’s weight distribution relative to that of the chair.

 

Wheel Camber

·        The angle of the rear wheel may be increased in order to:

      - Improve lateral stability

      - Improve turning

      - Improve wheel access

      - Increase efficiency of propulsion

 

 

 

Wheel Base Width

 

Adjustable axle sleeves provide the user w/ the ability to move the rear wheel assembly closer to or further from the side frame of the w/c.

 

Performance

Affected by:

·        Wheels and tires

·        Caster, fork and stem bolt

·        Caster angle

·        Caster reversibility

 

 

Inertia defined…..

zn   1.  The tendency of a body to remain at rest or continue in motion unless disturbed by an external force.  2.  Resistance to motion, action, or change.

z(The American Heritage Dictionary)

 

 

That being said….

 

We must keep the rolling resistance to a minimum.

 

But how?

 

 

 

 

Rolling resistance

·        Wheel size(larger=less, smaller=more)

·        Tire Material

·        Tire Width

·        Wheel alignment (toe-in/toe-out)

·        Weight and mass distribution

·        Surface terrain

 

Wheels and Tires

 

Spoke wheels

·        Light weight

·        More rigid than mags therefore more energy efficient

·        Spokes absorb more shock

;

 

 

Wheels and Tires

 

Mag wheels

·        Heavier than spokes

·        Less rigid therefore less energy efficient

·        No maintenance

·        Weaker than a spoke

 

Wheels and Tires

 

Solid Tires

·        No flats

·        Low maintenance

·        Heavier than a pneumatic

·        Less traction on wet surfaces

·        Poor shock absorption

 

 

Wheels and Tires

 

Pneumatic tires

·        Lighter than solid

·        Better shock absorption

·        Good traction

·        Better “float”

·        Higher maintenance

·        FLATS

·        May use a flat free insert

 

What is the role of a caster on a wheelchair?

 

BALANCE

;

 

 

Caster, Fork & Stem Bolt

·        Caster, fork & stem bolt combinations can have a dramatic effect on chair performance and energy efficiency.

 

·        Caster, fork & stem bolt combinations can also be used to achieve the desired seat to floor height

 

;

 

 

Caster Angle

·        The caster angle must always be perpendicular to the ground

·        Check angle if change

-         Wheel or caster size

-         Camber

-         Tire type

-         COG or STFH

-          Fork or stem blot

 

Caster Reversibility

·        Forward mount

-         Front stability

-         Heavy front end

-         Larger turning radius

·        Rearward mount

-         Lighter front end

-         Smaller turning radius

-          Less front stability

 

 

Notes: