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View Full Version : pic: 1712 version of JVN high reduction gearbox


Rich Kressly
04-22-2009, 07:53 AM
[cdm-description=photo]33863[/cdm-description]

Barry Bonzack
04-22-2009, 07:54 AM
That is one sweet trophy. If I won something like that I'd be trying to figure out how to run it around on the floor, and perhaps make it shift.

Rich Kressly
04-22-2009, 09:17 AM
That is one sweet trophy. If I won something like that I'd be trying to figure out how to run it around on the floor, and perhaps make it shift.

Well, not really a trophy. Petra just asked for the equipment to build it and bugged me until I gave the go ahead. When she finished it we created a mounting plate with a little placard to honor JVN's design, Mark Leon's "do the math, save the world" mantra, and Petra's effort. We will move forward using this to teach gear reduction calculations and gear theory to team members and to those who take our Engineering Design classes at LM.

rsisk
04-22-2009, 09:24 AM
teach gear reduction calculations and gear theory to team embers

:cool: I know it was probably a miss type, but I like the term "team embers". Are they the team members that keep the fire going ? :cool:

Stu Bloom
04-22-2009, 09:28 AM
That is one sweet trophy. If I won something like that I'd be trying to figure out how to run it around on the floor, and perhaps make it shift.

I don't think it would move very fast ...

Just out of curiosity (I'm not familiar with the FTC/VEX gears) what is the reduction per stage, and total reduction of that gear train?

Jared Russell
04-22-2009, 09:36 AM
12 stages of 5:1 reduction, total ratio of 244,140,625:1

Rich Kressly
04-22-2009, 09:38 AM
I don't think it would move very fast ...

Just out of curiosity (I'm not familiar with the FTC/VEX gears) what is the reduction per stage, and total reduction of that gear train?

Stu,

JVN posted the applicable calculations with his original design here:
http://www.chiefdelphi.com/forums/showthread.php?t=70627. And, as a finer point, these are VEX gears and I'm not sure what ratios you could produce using the current FTC kit gears.

ComradeNikolai
04-22-2009, 03:53 PM
I'm impressed by the gears, of course...

But the xkcd shirt is awesome.

rsisk
04-23-2009, 11:01 PM
Rich,

Any chance of making a parts list or design available for this? I would love to have our team build one.

Thanks

Rich Kressly
04-29-2009, 12:59 PM
We just followed from the original JVN picture and eyeballed it, selecting materials from what spare VEX part we had. JVN's version is much more compact than ours:
http://www.chiefdelphi.com/forums/showthread.php?t=70627

Here's an OK close up of ours:
http://www.chiefdelphi.com/media/img/de4/de4aa37b8eebaefe813a0f634275b627_l.jpg
most browsers will enable you to magnify the image, or just save it and magnify with software

Essentially, you just need to build a 12 stage reduction using:
4 VEX plates or chassis rails with appropriate width and length
12 12-tooth gears
12 60-tooth gears
1 big wheel on input side
1 small wheel on output side
stand-offs
shaft collars
fasteners
spacers
shaft to size (only one shaft runs all the way through the gearbox - the one at the bottom)

BJT
04-29-2009, 02:57 PM
So, if my math is right, a cim motor on the input would take about a month to get 1 turn on the output.

rsisk
04-29-2009, 03:22 PM
Thanks Rich, that is exactly what I needed to get working on one of our own.