Self-centering single-pivot sidepulls

Glenn Ammons said:

Also, I recall (but can't find in Google Groups) a discussion here
about another self-centering single-pivot sidepull, which had a
wishbone-shaped (IIRC) part that forced the calipers to return equally.
Does anyone remember the other caliper?

Found it. It's a "dog-bone" shaped part. The brake was by
Bridestone/Dia Compe. If you search in Google Groups for

dog-bone group:rec.bicycles.tech

you'll find the discussion. Or, visit this URL:
http://tinyurl.com/ydj8j8

--glenn

I've got one of these on the front of one of my fixed gear bikes, which
is unfortunately presently hibernating for the winter.

My pair came off a fully fendered Sekine city bike of ~1980 vintage,
that I bought at a yard sale, I knew they had a heck of a reach, didn't
realize it was a BMX part, that makes sense though.

IIRC the plastic part is pivoted and the cam action of it on one arm
moves the plastic piece which has a fork on one end which engages a nub
on the other arm.

Since I had a pair at one time, I imagine I have one in a junk parts box
somewhere in the basement, if I find it I will pull it apart to confirm
the operation and maybe snap some pictures.

Marcus