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Doug Griffith
12-18-2009, 1:53 AM
I've made some progress on the drive unit I designed and thought I'd share some of what I'm going through to get it into production. Of course, I've talked with the client and one from the first batch is immediately going to China to be disected and quoted. My guess is they'll come in far less than I am but use inferior materials. I doubt they'll use Delrin and their stainless will rust. The job will probably leave and then come back.

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The first photo shows one of the last pre-production drives. It is far simpler than the early prototype I posted here on SMC and has a lot more girth. The Gears are now Delrin that are "glued" and keyed together. All metal is stainless or aluminum.

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Here you can see two 50-up fixtures that fit in the laser. One cuts 3 holes in molded Delrin gears. The other cuts corresponding holes in the drive wheel which is actually from an RC car. The radioactive shaped pieces key into internal spokes of the wheel and align it for cutting. Both fixtures have metal dowels that help with alignment.

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This small fixture holds a single gear in place while reaming out for a hollow axle.

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Starting at the upper-left - this picture shows the wheel-to-gear assembly fixture. It has 3 built in hex keys that hold allen head bolts. The initial stage main fixture. A one-up gear cutting test fixture. An alignment fixture used to set squareness and height when hammering on a press fit washer.

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The last set of photos show the final assembly fixture. Everything is done upside-down. It speeds a process that used to take about half an hour down to a few minutes. Bolts are loaded into "receivers" that have built in hex/phillips keys. Components are then stacked in place. Then the lock nuts are added. The whole thing hinges up at the back in order to insert the pre-assembled axle/wheel assembly. One more white gear is missing in the photo. It mounts to the drive shaft at the bottom of the motor.

Also, all the acrylic is impact modified. It's tough stuff but stinks like no other when laser cutting. Amazingly, the Delrin that I use for the gears doesn't really smell at all.

Cheers,
Doug

Rodne Gold
12-18-2009, 2:17 AM
What does it all do?

Dan Hintz
12-18-2009, 7:56 AM
Doug,

Some really beautiful work (I appreciate the mechanical design of the tooling), but it's a shame to see all of that work may go to waste if they stick with China. In cases like this, I always get a signed contract to prevent them from taking my design and going somewhere else.

David Fairfield
12-18-2009, 10:02 AM
I love precision stuff like this, even if its not clear what the thingy does, its still a work of art. :)

Dave

Doug Griffith
12-18-2009, 11:26 AM
Thanks guys. I'll take a few more pics showing what it does.

About it going to China, I've known it all along. This drive is just part of a larger unit that I get royalties on so it's in my best interest to make sure it gets off the ground whether I build the drives or not.

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The above pics show how a few of the fixtures went together.

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Above:
A: Hex bit built into the fixture. 3 long bolts are dropped onto these as the first stage of layering the parts onto the long center dowel pin.
B: Recessed area allows fingers to grab gears
C & D: Oversized holes that laser "slag" goes through

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Above is one of last prototype units sitting in my living room. The drive unit mounts under one of the corner access hatches. This photo does not have the water distribution tree that rises out of the center hole.

Here's an incomplete animation I'm programming:
http://www.dogcollarlabor.com/smc/rpm/popRPM.html

Cheers,
Doug

Oh, Dan, in a few hours I'm meeting with the owner of Ledtronics again about a lighting unit. I may need your expertise services one of the days.

Lee DeRaud
12-18-2009, 11:36 AM
B: Recessed area allows fingers to grab gearsOk, that's just plain weird...is it just me or does that look just like the odd shape that showed up on Garrick David's business cards?:eek:
(This networking stuff is getting waaay out of hand...)
http://www.sawmillcreek.org/showthread.php?t=127311

Dan Hintz
12-18-2009, 11:05 PM
Doug,

What's the purpose of the four gears? Without knowing if four are actually needed, I would design it with two (or possibly even just one) and a cross bar mounted to the middle post with a gear at each end (or a '+' shaped bar if you need four spots).

Rodne Gold
12-18-2009, 11:20 PM
Wasn't this the thing you made for growing dope hydroponically?
hehehehehe

Doug Griffith
12-19-2009, 12:00 AM
Doug,

What's the purpose of the four gears? Without knowing if four are actually needed, I would design it with two (or possibly even just one) and a cross bar mounted to the middle post with a gear at each end (or a '+' shaped bar if you need four spots).

3 of the 4 large gears have a smaller gear attached to it with a special Delrin glue (that I'm sure will fail) and keys (Delrin dowels that are press fit into both gears). So there are actually 7 gears beyond the 2 white cast gears. The combo of gears takes a 1.1 RPM drive motor and gears it down MANY times to rotate the whole unit 2 revolutions per 24 hours. It also incredibly increases the torque. The very first gear inside the gear motor is only .125" in diameter. It rotates the large turntable (that the four 14" dia gears are mounted on) that is over 36" in diameter and has over 200 pounds of weight on it. It does this very easilly.

I could have gone with a digital approach like a stepper motor but the cost would rise and I'd still have to deal with torque and getting the power transmitted to the turntable.

Doug Griffith
12-19-2009, 12:03 AM
All I can say the "tomato" growing industry doesn't seem to be affected by the economy. Plus it's a pretty fun project to take from conception to production. If I only ate tomatos!

donald bugansky
12-19-2009, 2:58 PM
Maybe a greenhouse with artificial lighting (on a timer) would be cheaper. :)

200 lb tomato plant - those are some big tomatoes!

Doug Griffith
12-19-2009, 3:21 PM
Definitely cheaper. There are multiple timers in the unit plus an aeration pump, a circulation pump, a watering pump, and a GFCI unit.

200 pounds is overkill but each of the 4 smaller 14" dia gears needs to support it's own watering container full of grow medium, fluid, and a decent sized plant.

One of the benefits of this thing is tricking the plants into shorter grow cycles. More bang for the buck.

Scott Shepherd
12-19-2009, 5:01 PM
What's this country coming to when "tomato" growers are outsourcing their work to China? :) I think we're officially at an all time low ;)

Frank Corker
12-19-2009, 6:00 PM
You really scare me Doug. By the way I couldn't access the animation at http://www.dogcollarlabor.com/smc/rpm/popRPM.html ....but you still scare me :eek:

Doug Griffith
12-19-2009, 6:20 PM
I was deep into Disney Imagineering the other day. Those are the guys to fear.

The animation is in Flash 9 and works on all my systems. Flash 10 is out now so it's time for an upgrade there Frank!

Cheers,
Doug

Tom Bull
12-19-2009, 8:25 PM
2 revolutions per day? Seems counterintuitive for that to help the plant. Seems like 3 would work better. Does it "think" 2 days have gone by per day? Are these in a green house? They all rotate clockwise so do they rotate with or against the travel of the sun?
It all sounds purty fas-a-natin' to me.

Doug Griffith
12-19-2009, 8:35 PM
2 revolutions per day? Seems counterintuitive for that to help the plant. Seems like 3 would work better. Does it "think" 2 days have gone by per day? Are these in a green house? They all rotate clockwise so do they rotate with or against the travel of the sun?
It all sounds purty fas-a-natin' to me.

No sun involved with this. It's all timed and directional grow lights that corresponds with the rotation of the gears.

Frank Corker
12-19-2009, 9:29 PM
I was deep into Disney Imagineering the other day. Those are the guys to fear.

The animation is in Flash 9 and works on all my systems. Flash 10 is out now so it's time for an upgrade there Frank!

Cheers,
Doug

Doug not sure why it won't let me go to the page...I think it's something else maybe because I'm in UK.

Doug Griffith
12-20-2009, 12:05 AM
Doug not sure why it won't let me go to the page...I think it's something else maybe because I'm in UK.

What's up with that? Do you get that often? It's just an HTML page loading Flash through Javascript. Maybe when the script attempts to load an updated Flash player from Adobe it gets blocked. I've never seen that before.

Here is a direct link to the Flash itself:
http://www.dogcollarlabor.com/smc/rpm/rpm.swf

Bill Cunningham
12-20-2009, 12:26 PM
Works on FireFox just fine..

Frank Corker
12-20-2009, 5:45 PM
What's up with that? Do you get that often? It's just an HTML page loading Flash through Javascript. Maybe when the script attempts to load an updated Flash player from Adobe it gets blocked. I've never seen that before.

Here is a direct link to the Flash itself:
http://www.dogcollarlabor.com/smc/rpm/rpm.swf


The direct link is good. Sometimes with the 'foreign' sites it happens. You still scare me Doug...