[Robotgroup] Worm gearing questions

[Paul Atkinson]

John,

Although I recall the cars with the zip-pull thing, I don't have any laying
around. A couple of possibilities might be:
1- Use a cable/ zip tie as a track and find a small worm to drive it.
Similar to zip-pull car.
2 - Use Lego Technic which has worm and rack pieces and drive it with a Lego
motor.
3 - Use a piece of threaded rod and a regular nut, maybe even nylon parts.
I've used toilet seat bolts and nuts for a similar motion previously.

Any of those could be driven from under the "floor" or above the door. I
think it would be easier to hide underneath the set. I think you'll need
some limit switches so it doesn't travel too far, a reversible driver (relay
or H-bridge) to make it go, and maybe some smarts to vary the speed. Or you
could just use a hand crank to keep it simple, like an old radio tuning
mechanism.

Paul

On Tue, Feb 26, 2008 at 9:39 PM, john at cozmicfunk.com <john at cozmicfunk.com>
wrote:

> Hey fellow Roboters!
> I am making a gearing system for one my my miniature sets. I am
> designing a sliding door like in Star Trek that would slide back and
> fourth and I was wondering where I could find a worm gearing system and
> or components. I was thinking I could use belts but I need to not have
> any obstructions behind the door, the system has to be behind the wall
> that the door slides back behind as it opens/closes.
>
> I initially thought if I could find one of those SST car toys at a  Wal
> mart etc. They have not made those again for a few years, they do have
> this rip chord with teeth and a wheel with gears, as you pull the chord
> through the wheel it, it spins the wheel much like a chain on a
> motortcycle.  I could use that concept, but I don't even know where to
> look for them. I do know many of you inventor types have Worm gearing
> and that may also be a great alternative. Maybe Andre, Tom, Vern or
> Eric, anyone else out there have any idea what I am talking about, offer
> suggestions and a location to find such hardware locally?
> Thanks :)
> JPF
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