Ark 540rpm PTO adapter

[BraxtonPohlig 39]

I’ve been very interested in doing a 540 rpm conversion on my D200 just for the shear fact that I can buy implements I can actually use for it. The 2000 rpm implements have gotten so hard to find. Also, it would just be cool to me. Doing some research I found that ARK made a 2000rpm to 540rpm adapter box that was ran by chains and sprockets reducing it down to 540. Has anyone ever put this on a WH or built one? Thanks! 

[Pullstart 62,916]

I’ve never seen one, that’s pretty nifty!

[BraxtonPohlig 39]

I thought it would be really cool. I may start getting some stuff and doing some research on building one. The sprockets have an odd tooth count to be able to get it down to that. So that may be tricky to find but with enough digging I think I can make something work!

[ri702bill 8,345]

3 hours ago, BraxtonPohlig said:

I thought it would be really cool. I may start getting some stuff and doing some research on building one. The sprockets have an odd tooth count to be able to get it down to that. So that may be tricky to find but with enough digging I think I can make something work!

Hmmm the odd tooth count..... aka the "Hunting Tooth"  Is a Machine Design favorite to reduce repetative "ticking" in a gear, sprocket, ot timing belt application. Ask @Handy Don...

Suppose you ideally want a 2.1 reduction ( or overdrive) - gears of 21 and 10 teeth give you that, but if a tooth has a chip - the noise and wear are Very apparent.

Go to a combination of 23 and 11 and you get a repeating decimal - 2.090909090909 and so on. This spreads out the repitition with less wear, and less noise.

My Machine Design Professor REQUIRED a Hunting Tooth ratio on all the geartrain projects..........with the calculations....

Bill

Edited July 20, 2023 by ri702bill

[BraxtonPohlig 39]

8 minutes ago, ri702bill said:

Hmmm the odd tooth count..... aka the "Hunting Tooth"  Is a Machine Design favorite to reduce repetative "ticking" in a gear, sprocket, ot timing belt application. Ask @Handy Don...

Suppose you ideally want a 2.1 reduction ( or overdrive) - gears of 21 and 10 teeth give you that, but if a tooth has a chip - the noise and wear are Very apparent.

Go to a combination of 23 and 11 and you get a repeating decimal - 2.090909090909 and so on. This spreads out the repitition with less wear, and less noise.

My Machine Design Professor REQUIRED a Hunting Tooth ratio on all the geartrain projects..........with the calculations....

Bill

So I assume you recommend the 2000 rpm shaft being on the 23 tooth and the 11 tooth on the 540 rpm shaft? If this will work it would be a lot more simple and effective than all the sprockets and 2 chains. And it would make the size of the box a lot smaller as well. 

[ri702bill 8,345]

1 minute ago, BraxtonPohlig said:

So I assume you recommend the 2000 rpm shaft being on the 23 tooth and the 11 tooth on the 540 rpm shaft? If this will work it would be a lot more simple and effective than all the sprockets and 2 chains. And it would make the size of the box a lot smaller as well. 

Careful - I just used that ratio as an example off the top of my head.... I have NO history with the application.

[BraxtonPohlig 39]

19 minutes ago, ri702bill said:

Careful - I just used that ratio as an example off the top of my head.... I have NO history with the application.

I will try to do the calculations. Thanks for your help!

[Handy Don 12,237]

1 hour ago, BraxtonPohlig said:

So I assume you recommend the 2000 rpm shaft being on the 23 tooth and the 11 tooth on the 540 rpm shaft? If this will work it would be a lot more simple and effective than all the sprockets and 2 chains. And it would make the size of the box a lot smaller as well. 

The smaller sprocket goes on the input shaft and the larger sprocket goes on the output shaft. You are looking for an overall ratio of 2000:540 or 3.70:1.

In the image you posted, the box uses sprockets of 8 on the input shaft, 15 and 8 on the jackshaft, and 16 on the output shaft for a ratio of 3.75:1. It looks like #25 roller chain.

 

Using different length chains, the input and output shafts would be offset from each other, as the image you posted shows.

 

Let me know if you need more info! 

Edited July 21, 2023 by Handy Don

[BraxtonPohlig 39]

4 minutes ago, Handy Don said:

The smaller sprocket goes on the input shaft and the larger sprocket goes on the output shaft. You are looking for an overall ratio of 2000:540 or 3.70:1.

 

For a heavy duty chain (say #40, which has ½” spacing) and for a bunch of technical reasons, 15 teeth is as small as I’d go (about 2.6” diameter).

 

To get the desired reduction (≈ 3.70 x 15) in one chain, the driven sprocket would have to have 55 or 56 teeth which would be about 9” in diameter. This would be a pretty big housing and the output shaft would be offset from the input shaft so aligning with the implement input would be challenging.

 

Using two chains with an intermediate shaft lets you build a more compact unit (like the device in the image you posted), and lets you bring the final output shaft back closer to input for better alignment.

I’d propose that again the input sprocket be 15 teeth but the sprocket on the intermediate shaft be 29 teeth which is ~4.9” in diameter (odd numbers of teeth is preferred practice)

For the second chain, the intermediate shaft gets another 15 tooth sprocket and the output shaft gets another 29 tooth sprocket

This setup delivers an overall ration of 3.738:1 so your implement would turn at 535 rpm (very slightly slower than the 540 target). 

 

With each chain being 47” long, the two shafts would be a bit over 6” apart allowing for a pretty compact setup.

 

Let me know if you need more info! 

Wow. Thanks so much!

[Handy Don 12,237]

3 minutes ago, BraxtonPohlig said:

Wow. Thanks so much!

I edited the original since on re-examination the box you posted is for lighter duty so it uses, I suspect, #25 chain and smaller sprockets to achieve essentially the same ratio.

The #40 chain would be relevant for significantly heavier loading. 

[BraxtonPohlig 39]

Just now, Handy Don said:

I edited the original since on re-examination the box you posted is for lighter duty so it uses, I suspect, #25 chain and smaller sprockets to achieve essentially the same ratio.

The #40 chain would be relevant for significantly heavier loading. 

I definitely would have to agree. I believe this whole concept was meant to run stationary farm implements. But, I’d like to make it to where I could run any 4ft 540rpm pto attatchment on my D200. I think it would be awesome. 

[Handy Don 12,237]

Just now, BraxtonPohlig said:

I definitely would have to agree. I believe this whole concept was meant to run stationary farm implements. But, I’d like to make it to where I could run any 4ft 540rpm pto attatchment on my D200. I think it would be awesome. 

Yep, having the unit be able to handle the heaviest load you can reasonably predict with some cushion besides is my motto too!

I'm using #40 chain on ¾” keyed-shaft sprockets to drive a 36” flail mower off the front of an 18hp tractor. This makes me comfortable with both strength and longevity.

[BraxtonPohlig 39]

31 minutes ago, Handy Don said:

Yep, having the unit be able to handle the heaviest load you can reasonably predict with some cushion besides is my motto too!

I'm using #40 chain on ¾” keyed-shaft sprockets to drive a 36” flail mower off the front of an 18hp tractor. This makes me comfortable with both strength and longevity.

I’d love to see a picture of that!

[Handy Don 12,237]

Belt drive off the WH PTO. Chain drive to the flail drum.

This is somewhat similar to the way WH set up their one-stage snowblowers.