Superior Cranes brought out a "50 ton" crane to load an old P&H dragline. It weighted 63k pounds and was all the crane could lift. It couldn't pick it up from the side or swing with it.......
Crane "rating" as you called it, such as 50 ton, would be with the boom all the way up and fully retracted and set on fully extended outriggers. When you begin to extend or lower the boom any at all, capacity goes down proportional to boom extension or boom angle. Also, when boom is extended, capacity is diminished working "over the side" as opposed to "over the rear".
Typical complaint from someone that doesn't know cranes........The salesman said it had a radius of 120'......Why can't it lift 60 tons at 120'????.....That sure is a 'purty' 50 ton Grove, though!!
We loaded a large compressor skid onto a low boy one time. Couldn't have weighed more than 40 tonne, likely not even that. The trailer was nothing special in terms of capacity. However, they brought down a 125 tonne monster crane, and he could barely lift the load, simply because of the dimensions of it. He put the crane as close to the load as he could, but it needed to be closer. The operator was really worried she wouldn't pick it. Its interesting how rating falls off fast as the load moves away from the center of the crane body.
I guess everyone overrates everything to help sell it, this crane could barely handle a 16K pound counterweight off to the side, he did pretty decent once he backed up to the old crane but couldn't swing it or anything....I know nothing about cranes and am just asking because I don't know......
BradyHill1, no crane is overrated to sell it. On the contrary, cranes are very specific about capacities. There's a load chart in the cab of every crane that shows the operator what the machines capacity is for all the variations of boom length and boom angle. And crane operators go by that chart like it's the Bible. On the older machines, the capacities charted were typically 85% of tipping capacity, meaning the rig would actually pick up 15% more weight than the capacity stated on the chart before it tipped over. Newer rigs still rate by tipping capacity, but boom strength is also accounted for because newer lightweight booms tend to have more boom deflection than older heavy booms. Newer rigs also incorporate Load Moment Indicators (LMI) to lock out machine functions to prevent them being loaded beyond capacity. Also, a carrier crane on outriggers will have it's greatest capacity over the rear because then the front of machine, chassis and engine, become counterweight. When a rig is over the side, the front chassis and engine offer little help in the way of counterweight assistance. I'm not sure why the operator would've had difficulty with a 16K lb counterweight over the side, unless he was doing it "on rubber". But I can say that 50 ton machine would have had all it wanted picking 63,000 with some boom extended, which would have been required making that lift because of the necessary rigging.
To dove tail with Atcoequips post , A 300 ton crane will pickup 300 ton but thats right at the toes and short boom . The further away from the centerline of swing the less weight you can pickup . All cranes should have load charts in the cab of the crane so you cane figure out if you have enough capacity for the job . Here is a sample from a 17 ton Manitex boom truck . Its the only chart I could grab Quick You can see that the lift capacity is less and less the further from swing centerline you get . Also anything that is added to the boom counts against the rated load , Block , ball , any rigging is a deduction from the rated load capacity .
Thanks Tiny. :notworthy Notice the number in the top left corner; 5 ft operating radius, 77 degree boom angle, 34,000 lb. That's the max capacity of the crane. But notice the next number below it; 8 ft operating radius, 70 degree boom angle, 24,000 lb. Just dropping the boom 7 degrees and swinging the hook just 2 feet farther out drops a full 10,000 lbs off of the rigs capacity. That load chart is the Bible.
Also boom length makes a difference ,at boom length of 26 feet the rated load is 10,490 lbs @ 20 foot radius ........ still at a 20 foot radius with the max boom height of 91 feet the rated load falls to 3500 lbs
it aint like the old days. the days when you could walk a load out with a lattice boom and "get her light" now, these new cranes will structurally fail before they will get near tipping load. the chart is the bible, and if you don't read/believe it, you will find gravity biting your butt.
Thanx for the info on the chart. I see 20ft radius,78 ft of boom, 3500 lbs. I also see 90 ft but no rateing inside of 35 ft. Is that becuse it is too much angle (can't see that) But any how I was not able to see 3500 lbs at 91 ft. Oh maby skip that, 20 ft radius at 78 degres that might be how you got 91 ft of boom. there is a formula for that? correct? Or you can just shoot me. lol I like cranes, that don't mean I know them muzy : )
The 78 above the green line is loaded boom angle , 68 feet of main and 23 feet of jib.......you can get so much boom out that the closest Radius cannot be reached . the chart will reflect that.
Ditto on the crane chart, it's the law. As far as crane ratings go, I read in an old heavy equipment civil engineering text from long ago (when the cable shovel was still king) that a crawler, lattice boom crane standard rating was derived from the capacity at 25' radius with minimum boom length and the the boom angled so it reached that radius. It could probably lift more closer in but this was where they came up with the tonnage rating for the crane. I don't know if this still applies.
thanks for all the explanations, seems like all the older stuff was overbuilt, I knew the construstion equipment was but have never had any dealings with cranes before this one. Luckily for me my 35 ton lowboy will haul 35 tons of weight because if not this crane would have broken it. I told them if it was over 55k pounds, it wasn't going on my lowboy, that I wasn't getting enough out of the deal to break my trailer. The crane operator directly told me it weighed between 54k and 56k pounds to get me to haul it. They called when I got to the scrap yard and told me there was a misunderstanding, that it weighed close to 65k pounds. Here is what happened when the "know it all" crane operator did it his way. http://www.youtube.com/watch?v=F1zQZCbox7s
Well, in the first place, even if that old cable rig was only 54,000 lbs, I would have never waisted my time setting up my rig to make that pick over the side. I would have set up over the rear from the get go. I hope it didn't stress your trailer for that goof up.
the first crane they sent out set up backed up to the old cable rig and blew a hose while setting up. Then this young guy came in with the second crane and let me tell you, he was wide open and knew everything there was to know. He ended up having to set up twice to lift the crane but I'm not complaining, I was getting paid by the hour.....
LoL...maybe knew everything there was to know...except how to operate a rig.
maybe I should have said that he thought he knew it all and had a smart >>> attitude
Crane companies now post their load charts online, well some of them. Now looking at the chart posted here for the 17 ton. then compare to the crane photo. best guess is using that chart, you would be in the 8000 pound range, not the 34000 pound range. or about 1/4 the cranes total capacity..
To answer your question, a crane is rated on a perfectly level unyielding surface. The crane is configured with its basic or shortest boom (butt and tip for lattice all boom sections fully retracted for hydro) configuration. Yes ATCO is correct most all cranes include not only a stability component, but a structural component as well. They are usually separated in the load charts by either a bold line, shaded grey area or bold numbers. As to why the 50 ton Grove pictured is having a little trouble loading this 31.5 tn (if your weights are correct) I think a good look at the 50 tn Grove load chart will tell you. "chartshttp://www.manitowoccranes.com/MCG_GRO/Downloads/EN/download.asp?file=/MCG_Downloads/MCG_GRO/EN/Archive/AT/AT700B_LOAD_CHART.pdf [/URL]just guessing at the radius (about 20’ from c/r) boom length about 50’ and deductions (stowed lattice jib @ 693#, headache ball @ 338#. Block @ 1095# Boom head @ 145# and rigging @ about 300#) of about 2200#’s. he was way out of his charts, hence the reason he was having so much trouble. You can see by the charts the max lift for this crane is 100,000# 50 tons. This is with all boom sections retracted and the lattice extension off the machine and at a radius of 9’. In other words if you could put 50 tn on the rear deck of the crane about over the center of the drivers you could lift it up and set it down. at the radius he was lifting at (about 20') his chart was good for about 39,400 to 43000# depending of the boom lenght. i hope he doesn't hurt someone before he figuares out how to use his charts and more importantly believe them:Banghead!!!
Ditto with what big Iron is saying. The only way this happened is if it did only weigh 52-53,000 on the scale in the cab. Typically the lmi's show 2-3000lbs of preload weight (block, ball, stowed jib) so he may only have had 50,000 of crawler picked up. If it was actually 63,000, I don't think that crane would have picked it up. He wouldn't have had the chart to do it, and override switches don't keep you from breaking it, the chart would be all structural in that close. Be glad you're not on the news. Anyone else bothered by the lack of any cribbing under the outriggers, on that dirt, with a load like that? Anyone not think he had to hit the override to make the pick?
In the operators defence also, That is a tms 750- which has more ctw. and a better chart than the at 700 your using in your calculations.
crane operator, with all due respect, and I do respect you, but an operator that set his rig up over the side, even if it was a 100 ton, to attempt a lift like that has no operating defense. :tong
my CALCULATIONS were guess's at best with what little info was given the 750 chart i read was not any better (chart from the NCCCO website as I couldn't find it on the Grove site)its still in the 39,4 to 43,0# range using 40 to 50 ft of boom. regardless he was still way to far out to make a safe lift!
here's a picture of the ticket when it was unloaded at the scrap yard
You're right Big Iron, the chart isn't any better. I'm sure the scrap yard scale is right, they pay by the pound and I don't think they're going to overpay. I can't believe he got it up and on that trailer. I used to run a TMS 870, and it would have had its hands full with that weight. I guess I was really hoping that it only weighed 50, then if he was good for 44, we were all seeing pictures of a crane at 100% lift capacity. Not a good situation, but he wouldn't be the first operator to calculate his extra 15% from the seat. What the pictures are actually showing us is a crane at 140-160% over chart, a truly scary situation. If this was my crane and operator, his next job would be in the unemployment line. Cranes are expensive and people are priceless. (And yes, Atco, he should have backed up, but some operators are offended when they're told they do their best work over the rear. )
It's really easy to sit behind a computer in the comfort of your home and say that an operator is not good. Especially if you have never actually made a living in the seat of a crane. The reality is, if that operator said, "I need a bigger rig, not going to make this pick" maybe he would have been laid off. I don't know how the economy is where they are, or how much unemployment pays, I don't know what that operator's situation is so I am not going to judge him.
I'm not doubting the crane operator's ability to operate the crane, the older operator told him he needed to back up to the junk crane and he just had to pick it up on the side to show him that he could lift it that way. If I was his boss I would change his attitude or he would go in the unemployment line, nothing to do with his ability to operate the crane. Then again, I'm not a crane operator, so I don't really know how good of an operator he really is. He did get it loaded and didn't tear anything up so that's a thumbs up for him on one thing.
Hi Buckethead, I don't think any of us were necessarily judging the operator, more like pointing out the obvious. There are a number of us here that have and still do make our living in the seat of a crane, and some of us doing crane hire the way this operator was. An experienced operator would not have even waisted his time to set up his rig to attempt that lift over the side because of obvious reasons, 1) there's no doubt the machine is heavy and, 2) an experienced operator knows his greatest lifting capacity is over the rear. Moreover, if you're a crane hire operator, you are aware that every job you pull up on is one that someone is paying you (your company) big bucks per hour to have you there. You know that if you lollygag around and are percieved as "wasting time" by the customer, your company is going to get a call contesting the bill, which will drag you into the office for a sit down. With this in mind, you pull up on a job and make an assessment of the best way to set up your rig and the quickest way to get the job done with no incidents. The last thing that would enter your mind would be to set up over the side, just a foolish waste of time.
Having just a little experience on cranes and having seen the aftermath of more than one "accident", I would have to say that the operator put the company he worked for in serious jeopardy by lifting outside the load chart. Had there been an accident at the time of lift, the state and local safety officials would have found the operator at the least unqualified to operate the machine, and at the worst criminally liable for negligence. Ability means knowing all that needs to be known about safe operation of the machine. It doesn't just mean knowing how to start the engine and make the machine move. Now that the crane has been stressed at its structural limits, it will need to be inspected and certified again. All the quality crane hire companies I've dealt with had someone other than the operator making the decision as to how big the crane needed to be and how and where to set it up. Operators did have the power to shutdown a job for safety issues and there are state and federal agencies that can be contacted if personnel are mistreated for being safe. The operator needs more training on safe crane operation!
Thats the trouble with that whole situation , What stresses will show up later . Could the thing have been weakened somewhere that will show up the next time he picks up a man basket?? The crane owners may never know what happened if the operator keeps his mouth shut
I've always thought that if a crane ever picked up half it's rated capacity you best be really careful. 50 ton crane picking up 50,000 pounds......Everything better be perfect...
i have run cranes, a bunch of them. the one and only rule is THE CHARTS DON'T LIE. you, as operator, can be held civilly and CRIMINALLY responsible if and when someone is hurt or killed due to your negligence. these newer cranes are usually charted STRUCTURALLY. stability is not the issue. on an old, overbuilt friction rig, you could walk a load out, get 'er a little light, and it was usually ok. now, you can and will fold a boom up like paper. i have seen it more than once.
your right about the armchair QB, however i did make my living sitting in the seat of every thing from 20 tn squirt booms to 450 tn lattice boom rigs starting in the mid 60's and ending in 2000 when my eyes got bad enough to call it quits (i made that decision no one else and still get calls to come operate friction rigs several times a year). my comments were not to degrade anyone but to offer insight to operators who will be put in that position sometime in their career. i don't know about the rest of you but i would much rather be recieving an unemployment check than living with the fact i killed someone because i was afraid of losing my job. Big Iron
This is EXACTLY the problem!! In fact, its one of the biggest concerns I have when I run a rental rig. I ALWAYS do a thorough inspection whenever I get into a rental rig. Turning the key to get today's work done, can be hazardous to not only 'your' health but also the guy that's running the rig behind you............
Yes you are right, both you and Qball. I have been in that situation of refusing to do something unsafe, especially with Lulls. I did sleep better knowing I would NOT be the one to hurt/kill someone, and another job always came along. I am in a position to say 'no' if I really have to because unemployment is fair here, and there are lots of contractors to work for, I don't know if the operator of the Grove in those pics is as lucky as I am, in that regard. Just before I read this thread I was watching equipment videos on youtube and the ignorance of people's comments about equipment is unbelievable. So I probably overreacted a little.
No worries Buckethead. Those of us who have been, or are, crane operators know just how serious these machines and the job is. Any piece of equipment can cause injury, death, or property damage. As crane operators, we are aware of the unique thing that cranes do, lift things over persons and property. When things go bad with a crane lift, it typically is just that...bad. There are a number of things an operator has to be aware of and are responsible for; how to set up the rig, placement of outriggers and pads, how to prepare the rig for the load being lifted, and if he doesn't have riggers, the operator has to know how to properly rig the load. And it's his duty and responsiblity to do all this right, make the lift, without doing any damage or injury. To operate one in a foolish manner is ridiculous. Cranes aren't very forgiving to those who don't respect the machine.
I've pretty much always considered the 5 to 10 and maybe the 15 foot radius impractical for use.. in most every case... I would think companies would stress the fact that the crane is not as big as it seems... if someone wants a 50 ton crane then send one that the chart will lift 50 tons at 15 feet or 20 feet... I have been sent to a lift a propane tank.. 35 ton crane... 35 ton tank.. didn't happen until another crane showed up to to a 2 crane lift.. that's happens when office help rent cranes over the phone.. office help is the worst