NFB canes

From: John Miller (jamiller@qualcomm.com)
Date: Mon Mar 07 1994 - 10:55:39 PST


Hello folks,
Thank you Emerson for leading the NFB cane project. Three
possibilities come to mind for improving the long NFB cane cane
tip.

1. The most likely cane tip failure is for the metal to wear
through around the circumference of the bottom of the cane tip.
After it does so, the bottom "peals off." One solution to this
problem is to thicken the gurdle of metal around the circumference
of the cne tip. This should affect the responsiveness of the cane
very little. If maintaining the dimensions of the tip is critical,
perhaps the thickened metal could replace some of the rubber in the
tip. Doubling the thickness of this gurdle will double the
lifetime of the tip.

2. No single metal stands up to abrasion much better than another.
Engineers who design coal mining ore chutes coat the metal chutes
with plastic to protect them from abrasion. We could investigate
doing the same to cane tips. Both using a replaceable plastic boot
or applying a plastic coating would increase the life of a cane
tip. Of course, coating the cane tip with plastic would dampen its
frequency response.

3. The rubber of the cane tip probably does harden with exposure
to the environment. Some rubbers keep their original properties
better than others. UV radiation in the presence of smog, for
example, causes most rubbers to become more brittle. Solvents and
acids in street gutter water also weaken the rubber in the tip.
Personally, I have not noticed the rubber in my cane tips becoming
brittle. I also have not noticed a change in the frequency
response of the cane due to a change in the rubber.

An apoxy-based glue holds the carbon fiber cane together. I
recommend refinishing an NFB cane with an apoxy-based paint. It
will bond best to the material of the cane. The idea of mixing
white pigment in with the apoxy of the carbon fiber is an
intriguing one. How much would it weaken the apoxy matrix?

I suggest we develop a questionaire focusing on NFB cane failures.
Does it fail in a consistent way? I am interested in this
committee's answers to questions like the following: How many
years have you used an NFB cane. During this time, how many cane
tips have you used. If more than one, why did you replace the cane
tip? Make this a multiple choice question. Explain.

If Emerson is agreeable, I would be glad to poll the committee on
whatever questions the committee thinks relevant and report the
findings.

John

 
John A. Miller jamiller@qualcomm.com
                   (619) 658-3876
member, National Federation of the Blind



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