Help requested improving side dump mulch applicator

[jedidiahwiebe]

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

[ibdennyak]

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.

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

[clavius]

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

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.

[clavius]

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

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.

[jedidiahwiebe]

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.

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.

[NortonDommi]

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.

[clavius]

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...