November 16, 1994
To: NFB-RD Members
From: Emerson Foulke
A graphic embosser that uses a plotter of some sort will certainly
give better results than are possible when a brailler is used. The
stair step effect is avoided, and all of the embossed dots fall on
the curve. However, I don't think a spur wheel is the way to go.
It would be better to use a single, reciprocating stylus. I
suppose there are many ways to make such a devise, but the approach
that occurs to me at present is one in which the stylus mechanism
is stationary, and the material to be embossed is moved, under
computer control, in the X and Y dimensions. Dot spacing would be
determined by the speed of movement of the material to be embossed,
or by the "punch frequency" of the stylus, or both. If dots were
close enough together, one might get something close to a solid
line, and then it would also be possible to make a dashed line by
embossing short, solid line segments. Of course, a device of this
sort could also make the braille needed for labeling curves, axes,
etc.
It might be possible to have the stylus mechanism underneath, and
a structure on top with a cavity to receive the dot embossed by it.
The problem with this approach is that there could not be a
platform to support the material that is to be embossed. The paper
or plastic sheet would have to be clamped on all four edges and
stretched tight.
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