Re: A LEGO double-throw switch?

In lugnet.robotics, Kevin L. Clague wrote:

>> But I want to know where Brian Davis is.  He
>> started this blasted discussion  :)
>
> Me too!

   I'm here - just amazed at the chaos I kicked up :-). Incidently, I've grown
to hate those tank tread belts (those, originally, were going to be the
conveyor, but they are just too stiff). I've now got more ideas running around
in my head as to how to play with polarity switches than I know what to do with.

> Bryan wrote:
>
>> So - tilting one of the switches is probably the best approach.

   If all you want is a 45° phase shift between two polarity switches, I'm not
so sure. The polartiy switch assemblies I used in the BF GBC used a variable
geometry (accomplished by sliding cross-blocks along axles). Or should be easy
to use the same trick to make a composite axle where one end is rotated by any
arbitrary amount relative to the other. And, this way, the system is "tunable"
(as the offset between the two polarity switches might be *just* a little off).

> 45 degree angles are not so simple.

   They are, depending on how ridgid you need the system to be. Take a 16L beam
with two 1x2 plates and a 1x2 beam on the end, and pin a second 16L beam at 90°
to the first. Now you can easily mount an axle at 45° by attaching it to any
matching holes on the two 16L beams, and attach a third beam to the axle using,
say, two cross-blocks. It can actually be rather rigid if you don't use long
axles.

-- 
Brian Davis
(who's now working on a trolly for the crates that uses all those rails from the
Spiderman "save the train" set - those, at least, are low friction).