We had this happen to one of our Cat 320Cs last year while tearing down trees and piling them up. Zeigler Cat said they have never seen anything like that happen.
That's new. Never seen anything like it on any reputable machine.
I've seen a 345bl MH long reach boom crack and seperate on two sides and cracked on the third. it then twisted a bit. Cat replaced the boom with new and updated the stick by welding reinforcement plates to the stick....I might have a pic of it....I'll have to check
never seen one bend like that but i saw a volvo 160 stick crush like a tin can running a #4000 hammer once
That is pretty bad. We have cracked the sticks and booms on all of our 375's and 385's but not that bad.
That's a big tree and it puts a pile of torque on the stick when you pick it. I am always afraid that is going to happen to me. When i installed my hydraulic thumb the manufacture told me to make sure I set the relief pressure on the thumb circuit to 2500psi. That way, you can't apply too much torque on the various parts.
You just cant beat this forum for great training aids!
Looks like someone was operating the claw to tight with some big trees. Combination of weight and pressure will "blow out" and or twist a hollow boom. I've seen this more often on thumbs that are too weak or misused.
I have not seen one that bad but looking at the size of the tree if it was in the grab, and with enough leverage on it the the dipper arm would twist long before the tree would break. With enough force applied you can bend/break anything. Cheers RDG.
Wow never seen anything like that.:wierd
i thought cat's didn't break down?
We twisted a stick like that with a little to big of shear mounted to it. It was a 5800 Link Belt didn't get a good square bite with it and she twisted just like that.
I saw a Komatsu like that once. Operator tried using the thumb to push material into a big Diamond Z grinder when the rotor caught the thumb tines. Twisted the stick and about ate the thumb. Operator crapped his pants I heard and then thought it was funny. I don't know if they tramped him or not.
Well no wonder, it's a mechanical thumb and the operator was probably holding the bucket curl hard in. That tree is long and heavy and could easily pull over that machine. If that tree fell over on an angle with the grapple hard on it, or even trying to drag that thing it would twist it (as you can see) like tinfoil. The stick isn't designed for side loads or twisting like that, it's designed for straight in digging power. I'd wouldn't be surprised if they didn't warranty that, although if you do a lot of business with them they may bite the bullet to keep you happy.
We have done that before, but it was on a long reach hitachi
Great, now I have one more thing to worry about! I never seen one do that before. I did see it on the stick of a Case backhoe once when the operator put the bucket down in the ditch he had dug then picked up the machine and swung the back end accross the ditch. The bucket didn't have room to twist, and it bent the stick, though not as bad as that. I have seen some pretty heavy loading on dippersticks of excavators, Cat and others. Never had one do that, but I have seen enough other problems. Broken, both at the welds and in the middle of the plate. Boom ends rolled open, stick ends torn off, pins broken, you name it.
They don't it's just bent up a bit. jr
Pretty easy to see what happened here, inexperienced operator pushing the machine past it's limits. My guess is that a big tree was picked up off center and when it was lifted up with the dipper arm horizontal the weight off the tree bent the dipper arm. Anyway good lesson in that you gotta be careful when picking things up.
D&GExcavating, would you post a few pics of the adjustable mount, especially the the boom side.
Doh! Ok, so it was last year... But depending on the design and how it was welded, the adjustable part of the thumb mount may have contributed to it doing the twist.
I've seen stuff like this. Mostly cause the operator was swinging into a tree like is was a wrecking ball. Even saw the inside of a arm pealed up like a banana with the thumb hanging off to the side. This looks like too much side draft.
this operator has about 10 years of experience. Caterpillar did end up warrantying it. We have had this set of clams for 30 years and we first had them on a couple of old linkbelts (which are the same size as a 320 cat), then a Cat 320L, an old Cat 225LC, then the Komatsu PC200, the Cat 320BL, then these two Cat 320Cs. This is the first time this has ever happened to us and that we have taken down trees that big many times.
The operator has pushed the tree sideways with the slew until it started to lean over to the left and then grabbed the tree from the top of the trunk , as it fell on it's arc it has twisted the stick . I do tree work every day with mine and I can see it in my head what has happened .
I twisted the stick on our mini when it was new trying to move a tree that was leaned over a pile of rocks. When I lifted the end by the stump the top rolled off the rockpile and it twisted the bucket around. Not as bad as that though, but JD warrantied it.
WOW, warranty on a twisted dipper arm, they must love you. Whatcha tell em, poor welds led to a twist in the arm??????????
First off, we didn't tell them anything. They came out and looked at it and they were the ones that decided to take the stick and test the metal. They decided to warranty it. Not us. I would hope they love us because they get A LOT of business from us.
Being a good customer helps when it comes to getting warranty on something like that. If you were just a small time customer, you may not have had such good luck. I have been on both ends of that, and it seems to always work better for the bigger guy.