Topsoil screen

[Autotech]

Due to a multitude of small, and several large, excavation/grading projects around the place I find myself in the need for a small topsoil screen. I have searched for a small used plant, but there doesn't seem to be much available for less than $4000-$5000. I seem to be doomed to build one, but have had no luck finding any kind of plans. I'm pretty much at the point where I'll make it up as I go along, but I thought I'd see if anyone here had any leads/advice/input before I start cutting and welding.

I'm considering a small unit, maybe 4'x6', something I can batch load with a small FEL. At this point I'm considering a simple horizontal box screen being shaken side-to-side on a single pivot by a small (ex-lawnmower) gas engine. I'd have to manually dump the trash left in the screen, I'm considering hinges at one end of the frame with hooks opposite so I can manipulate it from the FEL. A system to automatically discharge the trash would be nice, but all the units I've seen that do this with tilted screens also use a conveyer fed input to minimize the amount of clean soil discharged with the trash.

Any thoughts or leads on info would be appreciated!

Gregg

[egon]

Autoteck:

Strangely enough I just finished one yesterday but very simple compared to what you have in mind.

Mines 4x5 feet with the screen on about a 25 degree angle. The highest point is about 4 feet. The frame is made from home milled poplar.

I dump a load of dirt on and then have to work the soil by hand to do the separation. This takes time as we have had lots of rain and everything is soaking wet. I used Paige wire on the frame to support a 1/2 in mesh screen. The bucket sits at the low side and the rocks will roll into it. Not very fancy. Can't show a picture yet as I don't have a digital camera.

As an indication of how much rain we've had the Cormorants just down on the river are wearing raincoats. It makes them look kinda funny when they fly by.

Egon

[BrianP]

What's Paige wire? [img]/forums/images/icons/confused.gif[/img]

[egon]

Sheep wire. Has squares in it. Might not be naming it correctly???

Egon

[Fawteen]

I'm working on just such a critter. I have a 4x5 box about 6" deep hung on "dogbone" pivots, with one end 2" lower than the other. It's driven by a crankshaft/connecting rod arrangement.

I ran out of Winter before I completed it, and have been too busy to get back to it. The initial plan is to drive the system from the PTO on one of my tractors, but I haven't scrounged up the parts to rig that yet. I may decide to drive it with an old lawnmower engine I have laying around if I can get the speed reduction I need. I plan to "shake" it at about 30 RPM.

If you're interested, I can post some photos of what I've done so far.

[Autotech]

Fawnteen -

Yes - If it's not too much trouble I'd love to see what you have so far.

I hadn't even considered using my tractor PTO as a power source (should give you some idea how new I am to the whole tractor thing) but the idea has a lot of merit - more HP, less speed. Hmmmm....

Gregg

[Fawteen]

Okay. Weather permitting, I'll get some pix when I get home from work tonight.

[Fawteen]

Thick 'o fog and drizzlin' tonight, but it's supposed to be nice tomorrow. I'll post some pix then.

[Fawteen]

Okey-dokey, pictures and a short narrative at the link Screener Pix

Bear in mind, it's still an unproven concept, as I haven't actually screened anything with it yet. My main concern is whether or not the 2x2 frame is strong enough to hold up under the shaking that it will be subjected to in operation.

[Autotech]

Thanks for the info. I am considering a sliding tray to keep all the motion in one plane, and figured I'd build the whole thing out of 2 or 3 inch angle iron.

A few details I'm still noodleing:
What size screen to use? I see you used expanded metal. I was considering something like 1/2" square wire fencing with some sort of support screen below it.
How did you arrive at 30 cycles per min? Is this from some sort of similar machine spec, or is it the result of calculations from your available materials?
If I stick with the sliding design should I use some sort of nylon slide block (ala rollback towtruck) or rollers to support the tray.

I'm probably going to use my tractor PTO as a power source, and I'm figuring that an old rear axle assembly, less one axle and axle tube, will give me the speed reduction (anywhere from 3:1 to 4:1 depending on what I find), change in rotational direction and height (PTO is about 12" off the ground, the tray should be about 48" give or take), and appropriate output (the axle flange will give me rotation in a horizontal plan to which I can attatch a connecting rod to convert to back and forth horizontal).
I can fab an attatchment to the axle flange to give me the ability to vary the stroke, and I figure once I get it running I can experiment with speeds, and then trial and error a counterweight on the axle flange to reduce vibration.
The other plus to using the tractor is I can fab a set of brackets to mount to the three-point which will both stabilize the whole affair, and allow me to either lift one end and use a dolly wheel, or if the weight isn't too bad simply lift the whole affair.

Anyone with any thoughts??

Gregg