Any mechanical engineers?

[illflem]

This is real application, no tricks. My pea sized brain is sore from trying to figure it out. Any takers?



I have a four sprocket machine that is missing three sprockets. The first 12 tooth sprocket needs to turn 8 times to make the last turn 5 times, the middle sprockets are both on the same shaft. How many teeth should the each of the missing sprockets have? None of the sprockets can be over 24 teeth.

 

[me4osu]

Need mo info

How many teeth are on the driven sprocket? Also, if both idlers are the same size, they have no effect on the overall drive ratio.



If you can make the drive ratio work only with the difference in drive and driven, make the idlers the same size.



If you are allowed to make whatever sprockets you want, you could do the following. Using your existing 12 tooth drive sprocket at 8 turns, connect it to a 16 tooth idler which would turn 6 turns. On the other end of the idler shaft use a 5 tooth sprocket to drive the final sprocket 5 turns using 6 teeth on the final sprocket. This is assuming each sprocket has the same circumferential distance covered by each tooth.

 

[Shovelhead]

HOLY COW!!!... ... . I'm just reading it and my head hurts!

 

[illflem]

me4osu, thanks, you got it! The 12 tooth drive sprocket is the only one I have, driven sprocket is missing. Was there a formula you used for this? There was actually more to this problem that I easily figured out. The 12 tooth's 8 turns equaled a wheel that needed to travel 20 ft. The 5 revolutions on the driven end turned a worm gear which caused a cone to travel one revolution.

 

[me4osu]

Here's the formula

N=speed

t= teeth (or diameter when talking pulleys)

*=multiply



It is a straight proportional relationship:

N1*t1=N2*t2



You just solve for whatever variable you don't know, and only work one pair at a time. If you don't know t2: N1t1/N2=t2 {algebra}



me4osu

WORKING Mechanical Engineer

 

[NVR FNSH]

I gotta ask... . What kind of machine is this?



Brian

 

[illflem]

It's called a research plot planter. It plants all the seeds you put in it evenly, no matter how many, in 20 feet. That's how we plant at different densities and spacings to determine maximum yields, required fertilizer, etc. The one I'm working on is a single row push behind that has been apart for at least 25 years. We have a couple of computerized multi-row tractor pull units, $30k+, but this one could come in handy for fixing mistakes.

 

[me4osu]

WHEW

Illflem,

I'm glad it is a real machine. I was worried it was a Rube Goldberg device. You know, the hamster turns the wheel, that strikes a match, which burns the rope, that drops the anvil... ... ...



I'm no farmer, but shouldn't you have planted by now??

 

[illflem]

Mostly done planting, but this is Montana, snowed a little this weekend.