Goggles

[gfish]

The new goggles are done!



Yes, okay, I made a steampunk artifact with non-functional gears. Dammit. But only because I had the brass gears sitting around unused after their failure in the electro-mechanical sunglasses. Once I work out a design/manufacturing approach that prevents them from binding, even with the floating central lens gear, I'm going to redo it all over again. This was really just a testbed for some of the design features for that future version.

These are way more comfortable than the sunglasses are, even with all the extra weight from the brass gears. I would design the leather gaskets (or whatever you want to call the toroids that cushion it against your face) a bit differently if I did it again, and I'd make sure to have enough brown thread on hand. The section of black look really bad. The lenses are just single layers of the polarizing film -- it looked silly not to have something in there, and they're transmissive enough to be worn at night.

All in all, a very successful thesis-avoiding sideproject. I should have some good pictures of me wearing them by the weekend.

Comments

[sistawendy.livejournal.com]

Damn spiffy! Where do you find the time?

[keystricken.livejournal.com]

Wonderful work! I look forward to more pictures.

[randomdreams.livejournal.com]

Remind me: what's the binding issue with the brass ones? Why do you think they bind more than the plastic ones?

[gfish.livejournal.com]

When I used the brass gears instead of nylon, the floating central lens gear would bind with any amount of rotation. As far as I can tell, this is just because brass-brass isn't as self-lubricating as nylon-nylon, and brass has less give. The added mass of the brass gear didn't help any, either. Having a floating gear like this just takes way more precision. I'm going to try to fix this on the Mark II version with more precise mounting of the gears (I can do CNC milling a lot easier in Seattle) and by adding another 3 idlers on each side, so the lens gear can't drift as far.

[randomdreams.livejournal.com]

What's your gear spacing like? Maybe back out the idlers a little so there's a slight bit of clearance between the gear teeth? I've been told that generally you want a piece of tissue paper clearance between teeth for smooth running. (Which, by the way, is apparently why we use involute gearteeth rather than cycloids, because involute handle increases in center-center distance gracefully and actually like it, while cycloid teeth get horrible.)
Hm. But then there's not really anything positively retaining the floating gear from falling out in your lap the first time you look down, which leads to a sore neck.
Hrm.

[gfish.livejournal.com]

Well, the real ones have retaining clips (http://www.cyphertext.net/images/Erato/Groups/projects/sunglasses/1248214876-pv.jpg) to hold the lens gears in place.

[randomdreams.livejournal.com]

I suppose you could also put washers over the idler gears that extend over the edge of the teeth of the floating gear, but that totally trashes the look.
Ideally you'd use herringbone helical gears everywhere because they'd be self-retaining, but...

[zzyzx-xyzzy.livejournal.com]

or use spiral bevel gears, so the pinions would hold the lens gear in place! the idler shaft could go across the nose bridge. probably harder to fabricate with all the shafts going at right angles though.

[stolen-tea.livejournal.com]

Pretty pretty!

[katyhh.livejournal.com]

wow, these look awesome!

[ionan.livejournal.com]

Sexy!

I can't believe no one has made this comment yet, but

[dymaxion.livejournal.com]

Ze goggles! Zey do nothink!

Had to be said.