Just some work pics

[crane operator]

Double acting cylinder.

 

[crane operator]

In having the relief line unhooked between the tractor and the trailer, and the tractor pump still putting out pressure- its possible that the relief valve on the trailer wouldn't be working correctly - there's no where for the relief oil to go. Then the cylinder bottoming out wouldn't activate the relief. Meaning something had to give, I'm just shocked that its the bottom of the cylinder and and not a hose or fitting. Any hose fitting should have been weaker than the weld on the cylinder end.

 

[skyking1]

Here are some random pictures I took yesterday on the way through Seattle. I can pull them out of here if you want, Crane Operator.
First one was a nice Christmas tree on a luffer right alongside I-5. It was a four part tree.






They have the floating bridge SR520 shut down to put a lid over part of it. They're putting up the beams this weekend to make about a 3 acre park.

 

[John C.]

You are right. Is the pump body cast iron or aluminum? Tensile strength on that weld should have been at least 60,000 and more like 70,000. A two wire hose is about 12,000 if I recall and a four wire about double that. That's why I'm thinking there may be more to the issue.

 

[crane operator]

I think its a cast iron pump, I put the wet kit on the truck, but it was a used wet kit from the junkyard, and it was longer ago than yesterday, so I wouldn't dare guess what the pump actually is.

Its all rubber hose between tractor and trailer, to the control handles, a "common" aluminum block that all 4 cylinders tie to, and then rubber hoses to all the cylinders from the aluminum common rail valve block. There was plenty of other "relief" items to blow.

It really doesn't matter, because I'm going to have to fix the cylinder and the control handle block (which likely has something cracked or blown in it- its also leaking), and I'm not likely to redesign the wheel here. The trailer is a 1998 or something, so its not really a design flaw, rather operator error.

 

[John C.]

I understand that. Just thinking of other things to check before putting it back together.

 

[crane operator]

I understand that. Just thinking of other things to check before putting it back together.

I appreciate it. I'll admit, I'm concerned that I may have piston/ rod damage, or even damage in the other cylinders. Operator said it blew almost immediately after he pulled the return to tank line. I'm debating if I need to take the blown cylinder down and check for damage or not.

The pump on the tractor still works correctly, they had it on my rollback and it was all operational.

 

[Welder Dave]

I'll mig it if I'm welding it myself. Its been too long since I stick welded anything. I may have to make a walmart trip to the reading glasses carousel before I start, my close up vision has really gone down in the last year.

I think I may make up some rollers to spin it on as I'm welding it. Tack it all up and go for it- what's the worst it can do- leak or bust back off.

If you could roll it would be great. I'd weld it like pressure pipe is done. Tack it good in 4 places to hold the cap square. Then start at one of the tacks and put a smaller pass until just before the next tack. Then grind the tack out and the crater on your weld. Overlap the last 3/8" of your weld and weld to the next tack and do the same. On the last section grind the start of your weld and the tack you started at and over lap the start a little bit. Grind the 4 stops and starts and for the cap/2nd pass you could slowly weave about a 3/8" wide fillet weld. Run it fairly hot so it wets in good. It wouldn't hurt to have 1 stop so you could grind the start to insure complete penetration at that point. Rolling should make for a good even weld.
Looking at the break in the original weld, part of it looks like there wasn't as much holding as other parts.

 

[Welder Dave]

One thing I forgot to ask. Does the end cap for the cylinder have a dished out center section so the rod/nut doesn't contact it when fully retracted? If not maybe you could modify the cap so the rod can't hit it?

 

[crane operator]

Most cylinders I've ever messed with bottom out on the piston on the end of the rod. Its how you set pressure relief/ check pressure relief, by bottoming out the cylinder. All the outrigger cylinders on the cranes are that way, so are the boom lift cylinders. When the piston hits the bottom end the pressure relief takes the fluid pressure away. Unless cylinder travel is mechanically limited by the physical structure that the cylinder is moving, I don't see many cylinders that stop travel by stops on the yoke/ exposed rod end. Only way you could do that would have the yoke beating up against the wiper with a collar.

 

[Welder Dave]

I think some cylinders have end of stroke cushioning. A spring or rubber bumper would probably work.

 

[terex herder]

Where end of stroke cushion is needed, I think the most frequent method is to have the piston, but not the rings, partially cover the oil port.

 

[oarwhat]

I can't believe you didn't split the hydraulic pump or some hose. We purchased a county plow truck with a lever in the the truck we thought was a control for the plow or dump. First time it blew a hose that was worn. After replacing the hose we didn't realize it was engaged so it blew the pump. It had an extra circuit connected direct to the hydraulic pump with NO relief. County mechanics are not to bright.

 

[crane operator]

I think the most frequent method is to have the piston, but not the rings, partially cover the oil port.

This piston would partially cover the bottom port when fully collapsed.

 

[kshansen]

I'm sure you have already thought of it and maybe I just missed it if you mentioned it. I would be hooking a test gauge into the line from the pump and see what the relief valve is set at. I have no idea what the normal pressure is but 2,100 psi is a fairly common pressure on hydraulic equipment. But don't take my word for that! I would sneak up on the relief valve setting when testing it after it's all back together. No need to do the repairs twice if there is a problem!

 

[crane operator]

I'm sure you have already thought of it and maybe I just missed it if you mentioned it. I would be hooking a test gauge into the line from the pump and see what the relief valve is set at. I have no idea what the normal pressure is but 2,100 psi is a fairly common pressure on hydraulic equipment. But don't take my word for that! I would sneak up on the relief valve setting when testing it after it's all back together. No need to do the repairs twice if there is a problem!

When we originally set up the wet kit, I didn't use a gauge in the line to set relief on the pump, I just kept bumping it up until it would pick the trailer neck up with my RT crane on it. The relief on the pump wasn't high enough originally, to pick up the neck when loaded. The relief on the pump- I don't think it would ever be able to port enough flow back without a return line hooked up. Its just a little needle seat thing- if I remember correctly. There are actually two reliefs, one on the pump and another on the trailer at the control valves. I've never messed with the one on the trailer.

I guess I'm not terribly concerned about pressure relief settings, I'm sure we just spiked the pressure hard with no return hose (making the trailer pressure relief inoperable- there's no where for the oil to relieve to), and as long as someone doesn't remove the return line with the pump in, we should be fine. I still don't know how he was able to even get the return line unhooked, with the flow going through it- but I do know he isn't likely to make that mistake again.

 

[crane operator]

Valve stack is repaired for the lowboy. Took cylinder to a welder friend, I just don't have time to mess with it, and cylinder shop is long lead time.

Reinstalled valve stack and capped off missing cylinder- 3 cylinders was enough to load my galion (44,000)- so it got delivered to a job yesterday. Now just waiting on cylinder. I doubt it will lift my RT (70,000) without the 4th cylinder, but who knows, its at a different site and I don't have to move it.

Manbasket work, and set a new exhaust fan. Full offset on the jib. Had some trees in the way.

 

[crane operator]

Concrete plant

 

[crane operator]

Got to run the new to us 90 ton today. It was a rough morning- computer didn't want to cooperate, and giving counterweight fault issues, but eventually got it working. I was a little peeved.

We set down a conveyor, and then got this rock crusher down off its legs, and put onto its wheels. About a 85,000lbs crusher. They had the intake feeder already off when we got there.

 

[crane operator]

Well all our hard running has caught up with us this week.

The new to us 90 ton threw a transmission code Monday, had boom in the rest and tray on the deck, so had to get a little creative to get to the transmission to trouble shoot. Had it going by noon monday, and it finished the quarry job and made it back home.



Link Belt 40 ton has broken a suspension/bushing pin, and it trashed bushing mount welded onto the crane limping home. We've got the bore mount being turned at a machinist, and the new bushing in hand.

Our grove 40 ton has a similar suspension, and it hasn't given us a bit of problems, but the one on this link belt is always busting stuff. I think we are going to rebush the whole thing after we get this band aided back together.