Friday, May 23, 2008

Knee Walker

I haven't had a chance to do any work on the bathroom in the last few days, not since trying and failing to dry fit the new medicine cabinet. It's not that I've been avoiding it - I certainly don't want to look into that hole in the wall forever. Nope, it's been from a lack of any free time whatsoever. Work work work.

But, hey, what's keeping me busy at work right now is pretty cool, and well worth the long hours. As many of you will know, my job sometimes requires me to drop everything and devote all (or at least most) of my efforts to design and build something that a patient needs now. It's nice to completely cut out the usual proooocccceeeessss that projects adhere to, and just let fly on a schedule long on hours but short on time - like I did in college. This is what I've been doing the last few days, and will probably continue doing through the weekend.

Some of you may have seen people getting around using a knee walker. It is a wheeled device that the patient rests one lower leg on, while using the good leg to scoot around. The patient's weight is alternately carried on the good leg and the contralateral knee, bypassing the injured foot. Some look like folding chairs with wheels, others look like backwards tricycles - two steerable wheels in front, one in the back. They are a way to avoid using crutches. I am currently custom designing and building such a device.

But why, you ask, do I need to build one, when the patient can go out and buy one at any time? Well, for this particular patient, buying one is simply not an option. Although medical devices are gradually being designed for a larger and heavier patient population, no one makes a knee walker to fit a 7'-plus, 600-lb patient. I can't go into many details, but suffice to say that the patient has a bum foot that the docs want to rest as much as possible, while avoiding keeping the patient immobile. There is a fear that the injured foot could get a whole lot worse if it doesn't start healing up soon.

So, I've been putting in 14-hour days for the last couple of days whipping something together. It won't be pretty, and not nearly as polished as a commercial unit, but should work. It's another of those backwards tricycle types. Instead of solid casters that are only useful indoors, this one will have 10" pneumatic tires. Instead of a nicely shaped and welded steel tubing frame (which we might have done if we had a month or two instead of a week), we're using extruded structural aluminum - an industrial erector set. Instead of a wimpy brake that presses against the wheel tread, we'll use a disc brake from a downhill racing mountain bike.

At some point I'll have pictures, but the design isn't even finished yet. The disc brake I picked up just this evening. The wheels are coming overnight and will get delivered to my doorstep Saturday morning. With these in hand, I can design the rear axle, brake mount, and front wheel mounts this weekend, and probably Monday, too. The machine Shop, as always, has done an quality job in turning out the parts I ask of them, making quick work of the stack of drawings I've given them so far. If all goes well, the thing should be finished and ready to give the patient by the end of next week.

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