22-04-2009 08:54

Barry Bonzack

Re: pic: 1712 version of JVN high reduction gearbox

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.

22-04-2009 10:17

Rich Kressly

Re: pic: 1712 version of JVN high reduction gearbox

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.

22-04-2009 10:24

rsisk

Re: pic: 1712 version of JVN high reduction gearbox

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 ?

22-04-2009 10:28

Stu Bloom

Re: pic: 1712 version of JVN high reduction gearbox

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?

22-04-2009 10:36

Jared Russell

Re: pic: 1712 version of JVN high reduction gearbox

12 stages of 5:1 reduction, total ratio of 244,140,625:1

22-04-2009 10:38

Rich Kressly

Re: pic: 1712 version of JVN high reduction gearbox

Stu,

JVN posted the applicable calculations with his original design here:
http://www.chiefdelphi.com/forums/sh...ad.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.

22-04-2009 16:53

ComradeNikolai

Re: pic: 1712 version of JVN high reduction gearbox

I'm impressed by the gears, of course...

But the xkcd shirt is awesome.

24-04-2009 00:01

rsisk

Re: pic: 1712 version of JVN high reduction gearbox

Rich,

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

Thanks

29-04-2009 13:59

Rich Kressly

Re: pic: 1712 version of JVN high reduction gearbox

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/sh...ad.php?t=70627

Here's an OK close up of ours:
http://www.chiefdelphi.com/media/img...4275b627_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)

29-04-2009 15:57

BJT

Re: pic: 1712 version of JVN high reduction gearbox

So, if my math is right, a cim motor on the input would take about a month to get 1 turn on the output.

29-04-2009 16:22

rsisk

Re: pic: 1712 version of JVN high reduction gearbox

Thanks Rich, that is exactly what I needed to get working on one of our own.