Building A small pull pan Type scraper

earthface · Jul 5, 2006

So how big is this to be? 2 or 4 wheel? What is the advantage of the fixed blade, I do take it to mean the cutting blade. Would that be foward or back dump? And with the fact that in the large scrapers ie 5 cu yds up, why build one. I can see it for the small 3 cu yds and smaller because they just are not built at least not many. The small ones for there size are expensive too. In the small sizes the ones I have seem to work very well for small tractors. I have just finished moving about 400 yds on 1 acre yesterday using these 2 units I have, of coarse 1 scraper at a time. I estimate that I have about 2000 yds to go to finish the job. But I have to stop to blade level my job.

QUOTE BY : Renze
"Anyways, after that i want to build my own style of pan, fixed blade pivot dump. It may take a year or so, but i dont think anyone of you will be interested as it's going to be the biggest my 5245 could ever pull (so when i rent it out to farmers, they can gear up and get full capacity of the design with their 100+ hp" tractors)

earthface · Jul 5, 2006

IN REPLY TO:Taylortractornut #63

Have you started this scraper yet? And why a paddle wheel loader if it is a small unit? With both of my scrapers At least in my dirt I have no trouble loading to a run over heap. It may vary in different soil types.

QUOTE BY :Taylortractornut
Im about to build a small front dump scraper for a landscaper here. I m trying to talk him into a paddle wheel to make the dirt finer as fill.

Taylortractornut · Jul 5, 2006

Tom the elevating and paddle wheel scrapers use a pair off chains with bars t drag the soil up into the bowl. takes less horspower the fill and it crubles the dirt better. the bowls are a bit taller than a regular scraper. Its gonna be down the road for now building this rig. We have a JD 762 paddle wheel scraper at work in the landfill we run. you dont have to have a push cat to load the 11 yards of dirt.

earthface · Jul 5, 2006

That is all true, but my opinion it is not needed for a 1.5 yd scraper ;((. I think it would help on VERY hard soil but I just havent had the need. That problem has occured to me and I have a couple simple ideas that could be incorperated in my units. I think to remedy the lack of HP for any scraper would be to reduce the cutting width, then increase the bowl length to make up for the lost cap.

Renze · Jul 5, 2006

Earthface:

When i want to move as much dirt as possible with a small 3500 kg mfwd tractor, i automatically turn to a 1 axle scraper. It simply needs the drawbar downforce to get traction, and when the drawbar is mounted below the rear axle, at say 40 cm off the ground, the lever of low drawbar to the center of the rear axle will give additional push on the front axle as well.
Most scrapers around here are more like pull type box blades, or bottomless scrapers. They require more pull because they dont carry the dirt. My brother had a contract job this spring, hired a 2,75 meter (110 inch) bottomless scraper hooked up to the high drawbar at 3 foot high (Dutch standard) and with the 6718 (70 hp 2wd) loaden with front ballast, could pull 4 cubic meter of tough clay, this was the maximum because the tractor couldnt keep the front wheels down, depsite the 200 kg front ballast.
4 cbm would be about 5 cubic yard. I think i want to go to 7,5 yard or 6 cbm.

The fixed blade front dump style, combines scraper earthmoving duty, and beam drag, or bottomless scraper fine levelling characteristics.

the real carrying scrapers never really caught on in Europe. Most contractors have a bottomless scraper though, and some have an ejector. Others are specialised in land levelling and use bulldozers sometimes.
There is a local contractor in the land reclaim business, with a big carrying scraper pulled by a Ford FW 30, but that scraper is just too awkward designed, the soil has to heap up high so it requires a lot of pull.

I dont see the use of a 1,5 yard scraper in my situation, with my land drag i can move enough dirt and do fine levelling with the same implement. Now when i had only my 1400 kg weighing 1965 Zetor 2011 to use, it would be a different story as this love bug just hasnt got enough momentum to use with the land drag..

earthface · Jul 6, 2006

As far as I can tell that ANY weight on the rear drawbar will take weight off the front wheel if it is connected behind the center of gravity of the pulling tractor. While some weight is desireable the amount you are contemplating is just out of thr question. 7-5 yds of dirt are near 20000 lbs and with a rear wheel scraper that nearly 10000 of that would be on your drawbar. I dont think a 100HP tractor of your size can handle that much.

QUOTE BY : Renze
It simply needs the drawbar downforce to get traction, and when the drawbar is mounted below the rear axle, at say 40 cm off the ground, the lever of low drawbar to the center of the rear axle will give additional push on the front axle as well.

Renze · Jul 6, 2006

Let's say that the lower drawbar is mounted 50 cm behind the rear axle, and 50 cm below the rear axle. The scraper holds 7 ton of dirt of which 2 is on the drawbar. The draft requirement equals the kerb weight of the empty tractor, which is 3,5 ton, of which 2 ton is on the rear axle and 1,5 is on the front axle. The axle heart distance is 2 meter (it's 2,14 meter on my 5245 but 2 meter is easier in this math.)
These are just estimations, close enough to real life scraping to get the general idea.

In the static situation, there is 2 ton at 50 cm behind the rear axle. That's 1ton/meter. At 2 meters from this point (the front axle) this will be 0,5 ton negative front axle load. 1000 kg will remain on the front axle.
This means roughly 4000 kg on the rear axle and 1000 on the front axle.

When the tractor pulls, there are two main points of force: the center of the rear axle, and the center of the drawbar eye. The tractor pulls with a force of 3,5 ton on this tow eye, and the corresponding lever is 50 cm, which causes a momentum of 1,75 ton/meter.
The result 2 meters further up front on the front axle, is 0,875 ton. The front axle load will be the 1000 kg, the outcome of the static calculation (at standstill) plus the dynamic force caused by the pull itself. this is 1000 kg plus 875 kg is 1875 kg on the front axle, and 4000 kg on the rear axle.
The static load index of the 5245 is 1800 kg up front and 3600 kg rear. That is the load to be bouncing on the road at 35km/h. At slow speeds (front loaders) the operators manual mentions a max. dynamic load at speeds below 10 km/h, of 2,5 times the static load rating. The tractor will do just fine, i just dont want to load my front axle that high because the bearing capacity is with front loader use in mind, not with heavy draft applications.

Off course there are loads of variables that have stood out of this calculation, like the reaction force of the wheel torque of the rear axle on the tractor body, which unloads the front axle, reaction forces in the front wheels etcetera. I hope you get the general idea, which is that any drawbar which is mounted higher or lower than the rear axle, causes a reaction force when the tractor starts to pull on this drawbar.

sandman2234 · Jul 9, 2006

I thought I might have a lead on a pan, but when I went to look at it, it was a "Jerzee grader" brand of grader.
Looks kind of like what a pan might look like, but the holding section has no way to hold the dirt if it is picked up. It merely fills up the box with exess, and drops it when it finds a hole.
This one looks like it might take a dozer to pull it. I don't think my 70 hp JD is going to pull it, unless I am totally off base on it.
David from jax

Renze · Jul 9, 2006

David, it seems that the machine you describe is the same as what i called a "bottomless scraper" in my previous post. In Holland we call that type of machine a kilver box but i dont know if theres an official English name. It's allmost the same as a pull type box blade.

sandman2234 · Jul 9, 2006

In a very loose sense of the word, you could call this a box blade. It is more of a box than the traditional box blade, with about 3' sides. A cutting blade at the rear of the box, that piles dirt up in fron't of it. It has wheels that are mounted behind the box, giving it an ability to control the depth of digging. Across the front of the box there is a location for a pin, which I assume to be for a drawbar to hook up to. It also has two arms which fold inward in the front, that MIGHT slip up under a tractor or dozer giving it some sort of guidance or strength (not sure why they are there)
I have requested pictures from the owner, for me to post here.
David from jax