Help requested improving side dump mulch applicator

Hey All, I built this thing out of a small manure spreader a few years back. Really all I did was remove the beaters from the manure spreader and then bolt on a treadmill for the side dump conveyor. The unfortunate thing is I built this thing starting with a manure spreader that is ground driven. So this means that I am locked in to a particular speed of the apron chain (a kind of conveyor that pulls the wood chips to the back of the wagon). I would like to convert the drive mechanism of the apron chain to hydraulic drive, but I do not know how to select the right hydraulic motor size or rating. An older farmer stopped by today and said that he figured 20 or 30 hp would do the trick, but I don't know how many foot lbs torque rating to look for when buying a motor. How much do I need to gear it down to get the right speed? (very very slow!) What do I use for a speed controller? Do I even need to gear it down? Do hydraulic motors have all their torque at low rpm?

I had my wife take a video of the tool a few years back. Unfortunately no matter how hard I try I simply cannot seem to get her to keep the camera on the tool and off the scenery. This is the best I have got.

https://youtu.be/vNWuKg8N5mo

Thank you for any help hyraulic gurus! I wanna start building with hydraulic motor power!

Look up the Surplus Center in Nebraska on the interwebs and download their catalog. In the hydraulics section they have the specs for torque, hp, gpm, and rpm to help des9ign your system. You will probably want a gerotor type motor....low rpm, high torque.

Thanks very much for your reply. The one thing I'm still wondering about is what would be about the right specs for the job? 5000 foot lbs torque? 50 thousand? What about the rpm? I'm thinking one or ten rpm... But if that even feasable? Do hydraulic motors even have enough torque at low rpm? Or is torque independent of rpm?

Unfortunately, I would have to have the machine in front of me to give you numbers, but first we have to put things in perspective. I am going to guess that your spreader loaded weighs maybe 2000 lbs. it is ground drive, so it needs enough traction to drive the beaters and apron. Probably 75% of the power is used by the beaters. If your tractor develops 35 horsepower, the apron uses a small amount of that because it is also powering the beaters, pulling the spreader, and moving itself. If it were mine (ingenious use of an old spreader by the way), I would get about a 5 hp engine and a reduction gear of some kind and power it that way. That would give you a nice range of speed rather than being limited to one,,,,,,just throttle the engine up and down.

That would also help you design a hydraulic drive. A Predator 212 engine develops 6.5 hp at 3600 rpm and about 8 ft lb of torque at 2500 rpm. If you want to run your apron at 25 rpm, it would require 800 ft lb of torque with a 100 to 1 reduction gearbox.

I would suggest you have your lady count the revolutions' of you apron sprocket as you run the machine and start from there.

Ibdennyak Well... to be honest the small engine does sound like a pretty good idea. Probably would be a lot cheaper than installing rear remotes. on my tractor and then the hydraulic motor.

When you say that the small engine idea would give me a nice range of speed rather than being limited to one... is that to say that with hydraulic I would not have a nice range of speed? I do want a range of speed. And I want it easy to adjust from walking behind the tractor.

There are hydraulic motors with way more than 800 foot lbs of torque tho are there not?

Yes, but at what rpm? A hydraulic motor with 800 ft/lb at 2000 rpm would probably be the size of a car engine. A hydraulic motor motor with 8 ft/lb at 2000 geared to 20 rpm will have the same 800 ft/lb but at 20 rpm.....closer to what you need, and you can hold the motor in your hand. Torque and rpm are inversely proportional. in your case the small one is what you want.

There are hydraulic motors with variable speed. They are called hydrostats. One source would be riding lawn mowers. If you can find about a 12 hp or so lawn tractor with an operational hydro, it and the differential would probably be about what you need. You would still need more reduction (sprocket and chain) but maybe only 3 ot 4 to one. The output torques goes up as the rpm goes down. The complication comes in that you need about 3000 rpm to drive it.

There are other ways to vary the rpm such as power dividers, but they become even more complicated to design. Another problem with hydraulics is heat. The motor and oil get pretty toasty under load.

You still need to find the output rpm of your apron you desire before you can design anything.

Okay, perfect. As soon as weather permits. Maybe even next week I shall fetch it from the shed in the back field and drive it around a bit and count the revolutions. And the feet per minute!

Alright I've done it. I have taken the side dumper out for a walk with my lady. I need the driveshaft on the apron chain to run at 2 rpm, but with some room for variability.

Also I totally get it. Here I thought I was reading 800-2900 foot lbs on the torque rating of these princess auto hydraulic motors but I was reading INCH LBS. Ooooooh kay. Gotcha. Lol

Now how do I figure out how much torque I'd need for this apron chain? The box on this spreader is about 3' wide and 10' long. And I can put about 3 yards of wood chips in it at a time. (REALLY high sides!) So that could be a weight of 1200-2400 lbs when full.

Thanks to anyone who can reply! Much appreciated.

For starters, that's a pretty clever setup you made. Nice bit of lateral thinking using a treadmill like that. I like it.

As to your question:

I am no expert on this stuff and have never built farm equipment, but just as a bit of a data point take a look at this spreader accessory for sanding icy roads:

https://www.fisherplows.com/products/poly-caster/

Depending on the model, one of those holds between 1.5 and 2.5 cubic yards of sand, at maybe 2000+ pounds/cubic yard. So maybe a bit more than your wood chips.

The whole thing is driven by two electric motors, one for the spinner that spreads the sand, and one for a bottom mounted conveyor that feeds the spreader. Both of those motors combined are powered via a 100A fuse. Assuming that it uses all of that 100 amps (which it obviously does not) that's consuming 1200 Watts of power, or in very round numbers, 1.6 HP total. Assuming no losses, 746W = 1 HP, and there are always losses. And, that is the total and is divided between the two motors. So less than 1.5 HP total to run the whole mess.

So while none of that directly answers your question, it would imply that if you had a 5 or 6HP small engine on there, you should easily have plenty of oomph to feed wood chips to your side conveyor, I think.

Just some food for thought.

Edited to add:

Rather than adding rear remotes to your tractor, maybe you could drive a separate hydraulic pump for your mulch spreader off the tractors PTO. A bit of added complexity, but requires no major alterations to the tractor. Just another option.

That's a really good data point. Thank you very kindly. I suppose it would be nice to take into account the coefficient of friction on that sand spreader machine vs the friction on my spreader. BUT your point is taken. Amazing! I guess if you lower the rpm of a motor by a factor of 1 or more thousands you must really increase the torque!!!

I am still having trouble deciding hydraulic vs small engine. What I really need to know is do hydraulic motors have the capability to run at lower rpms than a gasser? With a gasser I know I will need to run two 100:1 gear boxes. That's a few dollars. Now with a hydraulic I do not know... do they run at 20 rpm or 2000? Can any one tell me? Whilst the rear remotes on my tractor will cost some, and all the hydraulic lines... So will multiple gearboxes. Even the huge pulleys to reduce gearing cost a pretty penny. Is there anyone reading this that can shed light on hydraulics?
Thanks!

So once again I will preface all this with the comment that I am not a pro with this stuff but have had some significant exposure. But please DO NOT take my advice as as any sort of last word. I am sure there are a lot of details I am overlooking here. You have some homework to do.

With that said, here is my take. You can make a hydraulic motor run at any speed you want. Think of a machine like a skidsteer Bobcat that utilizes a hydraulic drive. . The engine is running constant speed at maybe 2000RPM driving the pump, but the hydraulic motors can be driving the wheels at just a few RPM if you are creeping it along.

To get the required pressure and flow, the pump needs to turn at some specified speed that is determined by the design of the particular pump.

So long as the pump is supplying enough flow & pressure, you can vary the flow to control the speed of the motor. That is essentially what the hydrostatic drive on a tractor does. The pump runs continuously at whatever speed the engine is running, and you vary the flow to the hydraulic motor to control the speed of the tractor. More flow = more speed. Because the pressure is always pretty much the same, the torque you supply will remain the same as well. So in theory, you can have full torque at zero (or near zero) RPM. Of course theory and the real world are not quite the same thing, but it's pretty close to that. This is why things like skid steers and tractors use hydraulic drives. It gives you the ability to control lots of power quite precisely. The hydraulics serve as the gear box, essentially.

There are subtleties involved of course. You can't just valve off the flow from the pump, it is either diverted or you need a variable displacement pump, etc.

I think that what you want to do should be within your capabilities with a bit of research. I don't know what would be better, the small engine or a hydraulic drive. Like any engineering decision, it is a series of tradeoffs. No doubt either approach can be made to work well, they each have different strengths and weaknesses. The application and your preferences will dictate which strengths and weaknesses are most important.

You may want to take a look at the surplus center website (I think someone may have mentioned this already) at their technical info page here:

https://www.surpluscenter.com/Tech-Help/Tech-Help-Home/

They link some helpful videos and have calculators about hydraulics to help with the design work. Lots of other info on the web as well. If you prefer to read a book, this is a decent basics book that will get you in the ballpark:

https://www.amazon.com/Hydraulics-ro...p;qid=&sr=


I am sure there are lots of similarly good books out there. Hope that helps a little.

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Originally Posted by jedidiahwiebe

Amazing! I guess if you lower the rpm of a motor by a factor of 1 or more thousands you must really increase the torque!!!

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This is exactly right. If you are using a gearbox to decrease the speed by a factor of 100, then (ignoring losses) you INCREASE the torque by the same factor of 100. There are always losses of course, how large those are depend on how much reduction you are doing and what mechanisms you use to achieve that reduction.

the gerotor type of motor is a high torque/low rpm type of motor. Gear and vane types are generally more high speed. If you know what the flow rate of you tractor is, you could determine what the output speed would be. Of course the only way to vary the speed is to change the rpms of your tractor. You could plumb in a speed valove that diverts a portion of the flow back to the tank, but that will add extra cost and complication.

A hydrostatic transmission would be another good choice. Usually readily available in lawn equipment, and that would give you variable speed and even reversing. It would still more than likely require additional gear reduction.

One thing I didn't think of earlier is that any ground driven spreader I've ever dealt with (yeah, I'm that old) has a variable speed built into it. Usually there is a ratchet system that changes the number of teeth picked up by each ratchet motion. Might want to look your mechanism over a bit closer. Your answer may be ri8ght there.

Clavius. Really helpful. This is great. This is what I was hoping to get an understanding of. I like what you said about what I should do should be within my capabilities. Truly installing a gasser motor and some gearboxes + pulleys is well within my capabilities. However the other option may not be. To be honest I usually do get a kick out of taking on projects that are beyond my capabilities. It's generally an anuual event here. But I just got a call back from Kubota and they claim that installing rear remotes (or accessory valves whatever kubota calls them?) will run me 1100 canadian dollars. Yuck.

I'm making progress tho. Have made contact with various salvage guys... gonna see what they've got for gearboxes and pulleys.

ibdennyak Thank you this is also very very helpful. It is feeling so much closer within my grasp now. Actually variability in tractor rpm might just give me enough variability of flow rate. I still have to price out both possible system designs.

Yes my ground driven spreader does have the ratchet system. I am quite familiar with that part of the maching. However even at max speed it's slightly less than half the rpm I need on the apron chain driveshaft.

Would it be possible to speed it up somehow? Either change a few sprockets, or increase the stroke of the ratchet????? Just spitballing here.....been a while. That might be cheaper and easier than anything else.

Wouldn't that be great. I have wracked my brain for a few years tryin a figure that out. I'll post a pic for you see if you see any way to speed it up.

Here's a vid of the ground drive system https://youtu.be/ZB3fa4a2kaI

If doing it with an engine and pulleys is the approach you are most familiar and comfortable with, then that is a perfectly good reason to use that approach. The cool stuff about these projects is that there are lots of right answers and you pick the one that works best for your situation.

A few other thoughts:

The suggestion made by ibdennyak of using a hydrostatic transmission from an old lawn tractor is a really good one. If you drive that with your gas engine (which is what it was designed for in the first place anyhow) the output side will give you variable speed and chances are good that the speed range will be much closer to what you want for your feeder anyhow. You can tweak the final speed range with pulleys, etc. Excellent suggestion I think.


Thanks for the video of how the wheel drive works. Interesting mechanism, thanks for educating me on that.

As for the three lobed cam on the wheel drive setup, rather than making the ratchet move more teeth each throw, could you make that into a six lobed cam so it moves twice as often? Or maybe move the cam off of the wheel axle onto its own shaft that is chain driven off the wheel at twice the speed? I suppose you could add levers to make the throw twice as long, not sure how easy that would be.

You could always cut some scale linkages out of cardboard, nail them to a piece of wood and try adding stuff to mess around with different arrangements. Sort of a backyard CAD system.

Fun stuff just to think about.

This is the most astonishing thing about asking for help in these kind of forms. I never would have thought of that!

I didn't even put it together in my head that it was a cam. Seems obvious now...

Quote:

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Originally Posted by clavius

If doing it with an engine and pulleys is the approach you are most familiar and comfortable with, then that is a perfectly good reason to use that approach. The cool stuff about these projects is that there are lots of right answers and you pick the one that works best for your situation.

A few other thoughts:

The suggestion made by ibdennyak of using a hydrostatic transmission from an old lawn tractor is a really good one. If you drive that with your gas engine (which is what it was designed for in the first place anyhow) the output side will give you variable speed and chances are good that the speed range will be much closer to what you want for your feeder anyhow. You can tweak the final speed range with pulleys, etc. Excellent suggestion I think.


Thanks for the video of how the wheel drive works. Interesting mechanism, thanks for educating me on that.

As for the three lobed cam on the wheel drive setup, rather than making the ratchet move more teeth each throw, could you make that into a six lobed cam so it moves twice as often? Or maybe move the cam off of the wheel axle onto its own shaft that is chain driven off the wheel at twice the speed? I suppose you could add levers to make the throw twice as long, not sure how easy that would be.

You could always cut some scale linkages out of cardboard, nail them to a piece of wood and try adding stuff to mess around with different arrangements. Sort of a backyard CAD system.

Fun stuff just to think about.

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I like your idea of adding lobes.....or making them taller, at least until something gets bent. Changing the length of the arms would do it too....or a combination.

My private joke is that I have been using CAD for years......cardboard assisted drawing

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Originally Posted by jedidiahwiebe

This is the most astonishing thing about asking for help in these kind of forms. I never would have thought of that!

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It is, that is why I like reading through this and other forums like it. I always learn something new. I had no idea that was how one of those spreaders works, I've never really been that close to one. Really clever device.

It's fun following these sort of projects and thinking through the possibilities. Even the ideas that turn out to not be all that good help sort out a good solution. Brainstorming is one of the most fun parts of the process. Please keep on posting updates as the project progresses.

Quote:

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Originally Posted by ibdennyak

I like your idea of adding lobes.....or making them taller, at least until something gets bent. Changing the length of the arms would do it too....or a combination.

My private joke is that I have been using CAD for years......cardboard assisted drawing

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Yeah, there are some good possible approaches here.

The study of linkages is actually pretty fascinating and very complex. Mechanical engineers (I'm not one...) take entire courses on studying and designing linkages and there is a lot to know. I have a few books around here on that topic, but have never really done more than skim through them. Maybe one day I'll actually try to study my way through one of them.

As for the "cardboard assisted drawing" same here, I've done my share too. And like the saying goes: "If it's dumb and it works, it's NOT dumb!"

I have done a fair amount of computer based design in my job and for my own stuff, but sometimes nothing quite takes the place of actually holding the parts in your hands and moving stuff around.

Quote:

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Originally Posted by ibdennyak

I like your idea of adding lobes.....or making them taller, at least until something gets bent. Changing the length of the arms would do it too....or a combination.

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I don't think I can add lobes. The cam follower bearing or whatever you call the roller that rolls along the cam seems to roll all the way to the bottom of the lobe valleys. If I added more lobes it would't have room for the ratchet to retract completely.

I guess ya it is ingenious. Irritating for me because I cannot adjust it the way I like! BUT lets talk about reliability.... I mean this wacky thing has been working for what? Gotta be more than 70 years. And you could fix any single part of it pretty dang easy. Even the ratchet mechanism we welded new teeth on when it was broken a few years back.

Hi,
In the video on the ratchet mechanism at 0.18 just to the left of your finger is the outside ratchet bar. If you leave the existing catch and spring on the existing pin with a couple of spacers you could drill a couple of new holes closer to the centre of the wheel move the levers closer to the centre. This will make the ratchet move over more teeth with each action and increase the speed of the chain. CA$1100 for a hydraulic remote is way over the top. I'm not familiar with your tractor but most have either plugged ports for fitting extra hydraulic controls or a replaceable plate where the existing hydraulic controls get their fluid from to enable extra valving to be fitted or you can bolt on an extra valve block ,(extend), what is there now.
Remotes can be a hassle though. You will want dry-breaks if you go that route and routing the hoses can be a pain.
If you go with an pony engine you have many options. Engine and hydraulic pump driving a small motor coupled by chain would be easy. Engine driving a gearbox,(old motorcycle?),and chain drive to your spreader gives you a number of speeds to vary whatever final drive ratio you decide on.
You could see how much power you need by hooking up a torque wrench,(scale and pointer type works well),and turning the mechanism by hand,(after disconnecting the ratchet of course!),to measure the torque needed.
Handy calculator here: HORSEPOWER TO TORQUE CALCULATOR to help understand the relationship between torque, R.P.M. and horsepower. Just remember to multiply lbs/ft by 12 if you want lbs/inch.
Hope that helps.

I like all of this brainstorming.

Measuring the load with a torque wrench is a clever approach. Good thinking.

OK, sounds like adding lobes to the cam is not ideal.
So another random idea:
Alter that cam that it spins freely on the axle and drive it off the wheel through a set of pulleys (or chain and sprockets, or whatever) at a two to one speed increase. It should no be all that difficult to do I don't think and far less complex that adding hydraulics or whatever.

This also is not likely a workable approach, but if you can spare the ground clearance you could change the wheels on the cart to be half as large in diameter. That would double the speed of the cam...