Fatal Flaws in Design, or User Flaws?


As noted in a prior blog, due to Anne’s disability I became immersed in wheelchair design. This blog is sort of a weird update and explains how design and user experience is a never ending interaction.
It touches on subtleties that are extremely difficult to predict as far as design and user effectiveness is concerned and also shows that when designing for disabilities, all solutions become custom design and smart users are as important as smart designers.

Wheelchairs exist for a wide range of people ranging from paraplegic ultramarathoners who can beat most able bodied runners, to truly paralyzed people who need to be pushed around.

Unfortunately Anne is in the latter category so all of Anne’s wheelchairs are of the push variety.
At this time Anne has four wheelchairs and I will probably buy a fifth in the next few weeks.

Anne has so many wheelchairs because there is no single wheelchair that serves all uses well. Anne needs to be moved around the house, where a transfer style chair works best. On the boat we use a reclining wheelchair. When Anne first left the hospital, we were supplied with a conventional big wheel wheelchair, and at Anne’s family camp in the Adirondacks we also keep a fat tire transfer chair that works reasonably well on the sandier or gravel paths around the camp.

I will discuss all because they all have annoying problem, some of which can be rectified and some cannot. I will concentrate on brakes because there is a bigger story in it.

Transfer Chair

This is a lightweight chair that we use in the house that I bought in a local medical supply store, with some input from the sales person. It is a 19 inch chair which is wider than it needs to be for Anne, and now I know that chairs like these need to have cut-away armrests to allow the chair to slip under a table or counter. The brakes on this chair are activated by levers on the rear wheels that requires the caregiver to bend down or kick the levers with their feet. The instructions actually state that the brakes are not to be activated by one’s feet, but the location compels the caregiver to do it that way and that is the way we do it. The brakes tend to loosen on the locking nuts and once every three months or so I have to tighten the whole thing up. Stranger than that, because the brakes are not terribly strong when the mechanism is not properly tightened, people may push the chair with the brakes on, and the actual brakes, which are aluminum brackets that push down on the wheel wore out in about 6 month and no longer could function as brakes. I fitted hose clamps on these brackets in way of the wear, and these now provide better locking than the original design.

Wheel Chair

This is the standard wheel chair that the hospital ordered for Anne. This was simply issued to us as a 21 inch chair which is much wider than Anne needs, and I wonder why the hospital did not get a narrower chair that is a better fit for Anne. A standard wheel chair allows the user to move the chair around by using the hand rims on the big wheels. Since Anne is paralyzed in one arm, she cannot do that and the first thing I did was to remove these rims which reduces the overall width of the chair and removes some weight too. And, as explained in my earlier blog, the footrests are simply stashed in my garage, (with three other foot rest sets from other chairs) and we use foot straps on all the chairs. (See first picture in this blog)

This chair is the type of chair that is also used on streets and sidewalks and occasionally our dog Harris tows it. In street use, the large rear wheels allow curb hopping and I can even get Anne up and down rather long stairs. This takes practice, is not for the faint of heart, and takes strength and technique.

The brakes are levers fitted on the front of the chair which would allow a user to engage the brakes, but in Anne’s case the caregiver has to bend forward to engage the brakes.

Meanwhile street use of these wheelchairs is a scary experience since sidewalk cracks or height transitions as small as 2 inches can violently stop forward motion on the wheelchair due to the small front wheels and the short wheelbase.

The lack of easily reached and modulated brakes and the horizontal handle orientation also result in scary downhill runs when hands are sweaty from the pushing exercise on a hot day. The brakes should be engaged by bicycle style handlebar mounted levers. Such brakes would be particularly handy when Harris is towing and needs to be slowed down.

Not until one uses a wheelchair on the street or in a park on a long hot day, does it become apparent that horizontally positioned push grips are uncomfortable, and even dangerous, since they provide little grip when hands are wet with sweat. The proper angle for these grips should be about 45 degrees down on the aft end of the grip. This both improves wrist position for pushing and holding back on sharp declines, and also makes it easier to lift in the back if needed. It is almost astonishing to think that wheelchairs are built with horizontal grips since, ergonomically, it is just wrong.

Reclining Wheel Chair

When I first started designing Aberration for Anne, I was considering a fixed recliner chair mounted in the wheel house and a transfer chair for use on the boat, and to also carry a conventional wheel chair for dock and street use.

For some reason I ended up searching for reclining wheelchairs and I found the wheelchair shown above.

It solved a whole slew of problems. I now had a chair that could function as an on-board transfer chair, a recliner and a street/dock wheelchair. An almost incredible weight and complexity saver on a boat.

However, it only worked because I got lucky. A reclining wheelchair requires a longer wheelbase to keep it from tipping, and the boat’s wheelchair lift was designed for the wheelbase of a standard wheelchair. Fortunately the reclining wheel chair fit on the lift with inches to spare. This lucky find allowed Anne to have one all-purpose chair on the boat instead of needing to carry three chairs aboard Aberration.

The chair even came with an arm rest cut out in the front which allows Anne to site closer to a table.

However, it does not mean the chair is perfect. It has two frustrating flaws (three, counting the incorrect handle bar angle). The handle bars appear to have brake levers, but these are not brake levers; these levers adjust the seatback angle. Besides the fact that handle bar mounted brakes would be a welcome addition to this chair (it has the reach forward brakes of a conventional wheel chair), an unsuspecting caregiver will engage these levers thinking they are brakes, and instead will lower the back rest without getting any braking assist. Caregivers use brakes all the time and seatbacks only get adjusted occasionally, and therefore the seatback adjustment should not be placed near the handle bars.

The other flaw is even stranger. The armrests are unusually short and provide a gap between the back rest and the after portion of the arm rest. The arm of a person seated in the chair can slide into this gap and actually start dragging on the aft wheels and allow a person to slouch to one side. Again, it boggles the mind why this problem was not discovered at the product evaluation stage. Fortunately, I found some longer after market armrests that close the gap even though these retrofitted armrests are rather weak due to the unsupported overhang.

There is one delightful benefit of the longer wheelbase of this chair; it rides much smoother on the street and is less likely to stall at small sidewalk cracks because the front wheels lift more easily on the longer wheel base. This chair actually has become Anne’s main expedition chair and is the chair that always rides in the back of car, whether we are going to the boat or not.

Fat Tire Transfer Chair

I decided to purchase this fat tire transfer chair to keep at Anne’s family camp in the Adirondacks. Both the floors and paths are rougher and I knew I did not have to do any curb hopping so this chair appeared to be a nice compromise.

I purchased it on Amazon. When I first unpacked it, I was immediately frustrated by the brake design. Squeezing would engage the brakes, but there was no way to lock the brakes. How stupid could a designer be, not to allow these brakes to be locked in place? I used rope loops to keep the brake handles pulled up, but that was frustrating to say the least, and required careful adjustment. Regardless, we soldiered on and the chair was quite suitable for the conditions at camp, which is where it remained. We carried the reclining wheel chair in the van for use on streets and during the rest stops.

While there is plenty of space for any type of wheelchair in the Pacifica minivan, we are getting a new caregiver who can drive, but she will be using a compact car, and I was wondering what wheel chairs were available that would fold more compactly than standard wheel chairs. I searched Amazon for compact folding wheel chairs, and the fat tire transfer chair showed up again. It actually folds quite compactly, but I hated those stupid brakes.

Then I happened to notice an additional picture.


Yes, this chair does have locking brakes. It was not a design problem; it was a user problem. If a user is not sufficiently smart to read the product specification, a designer cannot expect optimal user satisfaction.

Hilariously, my mother and my mother in law both use walkers, and when I mentioned my foolishness to them they both said: “Yes, that is also how you lock a walker in place.”

In my defense, I am almost certain did not receive any printed instructions with the chair, and there are other Amazon postings for this chair that do not show this locking brake feature.

Now the fat tire chair has risen from being one of the most frustrating chairs to one of the best designed chairs. Quite frankly, it is probably the best transfer chair in the business and is quite inexpensive to boot. While it is not a street chair, it could serve that purpose for relatively short distances.

But it is not the best possible chair.

This would be my spec for the best possible chair:

1. Reclining chair, with back adjustment away from handlebars
2. Handles inclined at 45 degrees and slightly higher than standard height
3. Brakes on handles, with locking feature
4. Continuous armrests, with cut away
5. The ability to clip on a single off-road front wheel with integrated footrest using the footrest fittings on the chair.

It would be near perfect for Anne and me. Unfortunately I have not found such a chair, and what may be perfect for us would not be perfect for the next person, so I do not expect it show up on Amazon any time soon.

If only the manufacturers would change that handle bar position. It would benefit millions of people who deserve to get all the help they can get.