Re: A LEGO double-throw switch?

In lugnet.robotics, Bryan Bonahoom wrote:
> In lugnet.robotics, Kevin L. Clague wrote:
>>
>> We can use two polarity reversors to create a three way switch.  Set two
>> polarity reversors side by side, linked by an axle.  Set it up so that when one
>> reversor is on (no matter the polarity), the other is off.
>
>
> Only one problem...if you link the switches with an axel, they will be oriented
> such that they are always both on or both off.  The on and off positions are 45
> degrees out of phase, not 90...

My bad!  I've not used them much, but when I thought about how they were
designed, I realized you are right.

>
> The concept is good (at least I think it will work electrically), you simply
> need to devise a reliable way to link the switches 45 degrees out of phase.

This means gears, but gears mean play.  One should be able to cancel the play by
using a total of four gears.  One gear for each switch, and two intermediate
gears.  If you "pre-stress" the gears (take out the slack when you put the
second intermediate gear on, the 45 degrees should be reliable.

Otherwise the percentage innacuraccy goes down as the number of teeth get
larger.

>
> Oh, and did I mention that pitsco will love you since the solution would take 4 switches (2 at each end)   :)

Did I mention that my biped Go-Rilla is their mascot?  I get a percentage cut on
polarity reversors and small pneumatic packs.  ;^)

>
> Bryan

Kev