Apron Issues..

[Soldati06]

Hey guys, sooo im in the Army deployed right now, were doing a huge mission that involves alot of scrapper spreading.. basically all of our material was made into a huge ramp for us to go over and pick up and drive it to our jobsite.. the question is and weve never had this problem before but at the end of our pass when picking up the material the apron doesn't wanna shut all the way even if you put it in float.. i had one of my mechanics replace a valve that controls the apron but that didn't do anything either.. now keep in mind these are from 1985... CAT 621B's basically just painted and put some bullet proof glass and a lot of armor on the cab lol.. but any help would be nice since my mechanics are stuck on stupid.. haha thanks again guys

 

[Soldati06]

Hey guys, sooo im in the Army deployed right now, were doing a huge mission that involves alot of scrapper spreading.. basically all of our material was made into a huge ramp for us to go over and pick up and drive it to our jobsite.. the question is and weve never had this problem before but at the end of our pass when picking up the material the apron doesn't wanna shut all the way even if you put it in float.. i had one of my mechanics replace a valve that controls the apron but that didn't do anything either.. now keep in mind these are from 1985... CAT 621B's basically just painted and put some bullet proof glass and a lot of armor on the cab lol.. but any help would be nice since my mechanics are stuck on stupid.. haha thanks again guys

p.s i forgot to mention that the material is a mixture of gravel and "getch" don't know if thats in the states or not but its like a material when watered it kinda clumps and hardens together but anyways basically rocks are preventing it from shutting, but shouldn't there be enough pressure for the apron to either crush the little rocks or at least kinda shove them out of the way?

 

[surfer-joe]

621's are not noted for having a lot of apron down-pressure. The apron might break up clumps of material and even smash a small rock or two, but it won't crush a lot and remember, that's a long area that it's trying to close on. You can ask for the tech to check the apron cylinder hydraulic down pressure. It may be off some and maybe could be adjusted back to spec.

Remember also, that when the apron control is in float, there is no down pressure in the cylinder. All that is forcing the apron down is it's own weight and the weight of the material that has rolled in over the back side.

Aprons not closing is a common enough problem. Look for other causes too, like rocks jammed between the sides of the bowel and the apron skirts. Check to make sure the apron trunnions are properly secured and that the apron arms are not bent or, again, jammed by rocks or debris.

Good Luck!

 

[BrianHay]

I imagine your mechanic would have checked this already but you never know, I don't know how much he has been around scrapers.

There are two spots to put the pin that connects the apron to the lift arm (technical name for that? I don't know) They are very close together but you would be surprised how big of difference it makes.

I normally don't recommend carrying your bowl high, but sometimes you have to. Lifting your bowl all the way up helps close your apron too.

And a little trick that you have to be VERY careful using. If you are having troubles getting your apron shut because of rocks in the way, skim the ground while closing it. That will push the rocks out of the way. But you have to be very careful because if you catch a rock with your apron that is planted solid in the ground you can bend the apron really easy doing that.

And as Joe mentioned rocks can get stuck in the sides too. It is good practice to periodically lift the apron all the way up and down a couple times every once in a while. Most rocks that get stuck in the sides will fall out when you do that.

 

[Buckethead]

I second every thing that Joe and Brian said.

And a little trick that you have to be VERY careful using. If you are having troubles getting your apron shut because of rocks in the way, skim the ground while closing it. That will push the rocks out of the way. But you have to be very careful because if you catch a rock with your apron that is planted solid in the ground you can bend the apron really easy doing that.

That's an old trick that my Dad and other older guys who broke in on old cable machines told me about. It helped me when I ran a Terex TS-14. (Hydraulic, but no down pressure for the apron) Be careful over there, Soldati! :usa

 

[sprknranger]

Also if rocks are preventing you from closing the apron, you can crack the apron up a bit and then back down real quick to help the rocks fall off the cutting edges, which are probably keeping you from closing all the way. It sometimes works but not all the time. If it doesn't, then as Brian said, skim your cutting edge in the ground to pack a lil bit of material in there to keep you from dribbling your load out before you get to the fill.

 

[Vantage_TeS]

That's a normal problem for the material you're in. Do the skim trick at the end of your cut. Basically close the apron while you're still cutting, then pick up.

 

[scraperflorguy]

When i was installing a 637D floor i had a operater come over and complain to me the same problem , every one was on his back about dropping dirt and rock all over the hall road. the only thing was it has only been going on since the mechanic had put in a new floor the week befor. when i looked at it the pin was in the top hole not the bottom,they were in dirt not clay ,after repinning it it ran fine.