Safe crane operation

[datadawg]

http://www.steelsoldiers.com/upload/misc/FM5-125.pdf
What a great resource. A long read, but I scrolled through it while eating lunch and learned a lot. Thanks for posting this.

 

[wanderingwillys]

Wrong, It is rated for the SWL being what is on the load charts, the military wreckers can easily be over loaded because of the duel use of the truck (recovery lift tow and crane use). ALL military cranes require a YEARLY CERITFACTION of the SWL (safe working load) at the SWR (safe working radius), this is FAR BELOW the tipping weight/distance or structural failure. I am guessing the CERT. is 110% of the SWL.

Probably not the best wording I chose but what do you think the SWL on the wrecker was based off of? The standards for mobiles include a 3.5 design factor multiplier - if you are within this limit and you go outside the allowable radius the machine will tip over prior to experiencing a structural failure of the wire rope or boom components. The boom components on the wrecker appear to be constructed with a higher design factor than the minimum 3.5 - industry standards are either 5, 7, or 10

So with typical 1/2" wire rope (IPS) the break strength is 11.5 ton (23,000 lb) - the SWL is found by the following - Break Strength (BS)/Design Factor (DF) = Safe Working Load (SWL) x Per Parts of Line (PPL)

So on my machine I run 3 parts of line - off the boom tip, thru the block, back thru the boom tip, and anchored at the block - this gives us the following:

23,000 lbs (BS) / 3.5 (DF) = 6571 lbs (SWL) x 3 (PPL) = 19,714 lbs (or 26,286 lbs with 4 parts of line)

This figure must then have the weight of the cable (.46 lbs per ft), block, and rigging deducted from it but already you can see we have WAY more wire rope capacity than the machine will lift according to the data plates and those plates were designed with a safety factor as well so I have yet to meet anyone who could successfully pick up a load that broke the boom on a wrecker without tipping it over.

Seen more than 20 wreckers retired from the Ft Lewis Complex as residue and cut up for scrap - not a one had a broken boom or heel pin. I have seen the cables broken from "Two Blocking" but even then there was no structural damage to the machine.

Hope that clarifies what I meant

Matt

 

[m16ty]

Lifting over the back, the boom will more than likely fail before you pull the front tires off the ground. Now the winch line may stall before this happens but I have seen buckled booms.

That's also why you have to install the boom jacks for lifting heavy loads.

 

[Csm Davis]

Okay the boom certification is only 10,000 lbs and I have watched and helped do one. I have the procedure floating around here somewhere the boom max lift is 20,000 with the legs.
I have seen at least 6 booms bent and all bent right at the rams. The front of the truck will lift if you pull to much with the boom I have done it. Guys just be careful if the boom or cable fails it can kill someone.

 

[wanderingwillys]

Ha ha - you mean like this?

sucked in to 13 - 14ft radius and still lifted the front picking off the rear - not saying it's right as it is most certainly NOT - but it was a thing...

That was only a tad over 12k of load...

My question is how were the booms bent then if you can pick the nose of the truck without collapsing the boom - the longer you extend the easier it gets to tip (and over the back is the hardest position to tip) - the only time I have heard to the boom breaking on a wrecker was when some guys tried to use the cable like a snatch strap and drive off with the block hooked to a stuck vehicle with the boom up...

I have seen and heard of broken swing gears from catching loads but not from operating the machine in a static position without a dynamic load.

 

[wanderingwillys]

PS - the plate says:

10,000lbs@10ft radius with the outriggers deployed (6700lbs on rubber)(2 part line);
20,000lbs@10ft radius with the outriggers deployed (3 part line);
20,000lbs@15ft radius with front outriggers deployed (rear stowed) and boom jacks to the ground.

So riddle me this? How does the SWL rating change from 6,700lbs to 10,000lbs to 20,000lbs by only adding one part of line and deploying the outriggers???

The outriggers give ZERO structural improvement to the boom!

Their sole purpose is to increase the footprint of the machine and keep the CG of the package inside said footprint - preventing tip-over.

In the photo's above I violated the table - went to 12,000lbs@14ft radius on the rubber - and what was the result? - the machine tipped over (well not all the way over since the load was allowed to stay on the ground). The load limit for the boom could not be reached as the load relieves itself as the machine comes off the ground.

The load required to lift the machine via the heel pin and the boom lift cylinders can change depending on radius but the actual bending moment at the lift cylinder pin will never get any higher than what is required to cause the machine to tip; all that changes is the length of the pry bar.

We can all relate to the fact that a 100ft/lb torque on an 18" torque wrench requires a stiff pull while a 36" torque wrench makes the job much easier - however the torque applied to the fastener remains the same regardless of the lever.

Just some food for thought

Matt

 

[Csm Davis]

Welcome to the wheelie club we have a thread for that. Never said it could be bent without the outriggers down. With the outriggers down you can bend it real quick.

 

[saddamsnightmare]

June 23rd, 2015.


Gents:


Probably more interesting for me is the lack of a boom tip anti whip line not being used on the wreckers, particularly the larger 5 & 10 ton units, to prevent the wrecker from flipping over backwards in reaction to a lift line parting under (heavy) loads. I was more familiar with 100 and 150 Ton American and P&H truck cranes, and I have seen many go over backwards when a hoist line fails on a heavy lift and the boom tip was not so restrained.

On the railroad 40, 100, 150 and 250 ton wrecking cranes, unless the lift is on the axis of the crane on the track, not only do we block the outriggers heavily, and even sometimes under the frame, but whip lines are always used on the boom tips to protect against a lift line or hoist block failure. It is, or was, not a pretty scene to see a 250Ton steam crane go over the embankment because of either improper blocking, lack of an anti-whip (back) line on the boom, or other such avoidable failures......Especially when trying to rerail a locomotive.....


No heavy lifting in this video, but some idea how ponderous our locomotive cranes could be in operation!

https://youtu.be/IZddfTjqSHw

Safety first is a very good policy to follow....


Also see:

TM-55-2230-201-10,
Operators Instructions
Crane, Railway Locomotive
Diesel Electric, American
Hoist and Derrick, 40 Ton
Model 840DE, 56-1/2 inch Guage
Model 1240 DE, 56-1/2,60-,63- and 656- inch gauges
Headquarters Department of the Army, January 1958


I could probably scan this as it is only 30 pages long if you would wish to add it to the TM's..... It is for the man who wants to own and operate a very unique item in the green iron stable, and it is not for the faint of heart (or wallet, likely!).

 

[USAFSS-ColdWarrior]

June 23rd, 2015.


Gents:


Probably more interesting for me is the lack of a boom tip anti whip line not being used on the wreckers, particularly the larger 5 & 10 ton units, to prevent the wrecker from flipping over backwards in reaction to a lift line parting under (heavy) loads. I was more familiar with 100 and 150 Ton American and P&H truck cranes, and I have seen many go over backwards when a hoist line fails on a heavy lift and the boom tip was not so restrained.

On the railroad 40, 100, 150 and 250 ton wrecking cranes, unless the lift is on the axis of the crane on the track, not only do we block the outriggers heavily, and even sometimes under the frame, but whip lines are always used on the boom tips to protect against a lift line or hoist block failure. It is, or was, not a pretty scene to see a 250Ton steam crane go over the embankment because of either improper blocking, lack of an anti-whip (back) line on the boom, or other such avoidable failures......Especially when trying to rerail a locomotive.....


No heavy lifting in this video, but some idea how ponderous our locomotive cranes could be in operation!

https://youtu.be/IZddfTjqSHw

Safety first is a very good policy to follow....


Also see:

TM-55-2230-201-10,
Operators Instructions
Crane, Railway Locomotive
Diesel Electric, American
Hoist and Derrick, 40 Ton
Model 840DE, 56-1/2 inch Guage
Model 1240 DE, 56-1/2,60-,63- and 656- inch gauges
Headquarters Department of the Army, January 1958


I could probably scan this as it is only 30 pages long if you would wish to add it to the TM's..... It is for the man who wants to own and operate a very unique item in the green iron stable, and it is not for the faint of heart (or wallet, likely!).

Thanks for posting up that video.

I can visualize in my imagination all of the steam powered cranes and shovels and other equipment used to construct the Panama Canal.

Oh, the glory days of steam!!!

Carry on.

 

[m16ty]

The boom flipping over backwards isn't much of a problem with hydraulic cranes, the boom cylinder will prevent this from happening.

You are correct about lattice boom cranes as in the vid though.

Also, the P&H and American cranes you mentioned have a massive amount of counterweight hanging off the back of the house. This also plays a major part in them flipping over backwards when something goes wrong.

I've seen pics of cranes flipped over backwards when they swing over the side with the counterweight installed and the outriggers aren't fully extended.

 

[73m819]

When rigging a load with steel slings, DO NOT put one end though the loop at the other end and pull tight cinching the load. USE a shackle for the following reasons,
1 -- The steel sling wires are just about file hard, it will be like rubbing two files together under load, the shackle is a softer metal, designed to ware
2 -- The steel sling WILL be bent around a MUCH SMALLER radius then it should be (the cable eye cable), there by bending and breaking the wires, again a shackle is MADE for this issue because it has a much larger radius If you use the right shackle for the size of cable sling you are using.

When rigging a load using nylon straps, DO NOT put one end though the eye on the other end pull tight, use a shackle of the proper size, the pulling though a nylon strap causes heat, this heat WILL cause a nylon strap to deteriorate at the rub areas, which WILL cause failure later on.

When you use a shackle there is a RIGHT and WRONG way, ALWAYS the bolt/pin goes though the eye, and the running leg goes though the U, the reason for this is if the eye is though U and the running leg is across the pin/bolt, it CAN/WILL either walk the pin/bolt OUT or tighten it TIGHT (I have seen shackles need to be cut because of this), also the U is designer for the wear of the running leg going though it.

Use the right shackle, a to big a shackle is no big deal, a two small of a shackle defeats the purpose of the shackle.

ALWAYS use the pin/bolt that comes with the shackle, NOT some pin or nut and bolt that fits.
ALWAYS look for deformed, excessive ware, the pin will not go in and seat, the U is spread, ect,. if any of these are found, THROW the shackle away.

USING the RIGHT shackle, the RIGHT WAY will extend the life of you slings and straps about 4 times of what NOT using shackles would be.

Remember a MISTREATED strap or sling most likely will not fail at the time of the mistreatment, but later after the injury has had time to grow.

 

[m16ty]

Ron made me thing of something about shackles. It's not really a safety issue but will save you a bunch of headaches. When installing a screw pin shackle, tighten the pin down until it stops, and then back it off just a fraction. Doing this will keep you from having to use a wrench to remove the shackle when the lifting job is done.

Another thing with slings comes to mind. Never use a choker hold to tie two slings together to increase the length of a sling. It will pull so tight that you'll never get them back apart. I see people do this all the time and the only solution is to throw them away.

 

[turnkey]

This is really great stuff to know and use the safe way to lift something....Worked for a Wire company in the 80's....They had head sets for everyone...Crane operator...guide and overlooker on site...3 people min to lift anything...worked great had to also learn hand signals...Again good stuff to know.

 

[saddamsnightmare]

June 24th, 2015.

Safe Crane operation, hand signals and sling / lift ratings from TM 55-2230-201-10:

 

[zebedee]

...
Another thing with slings comes to mind. Never use a choker hold to tie two slings together to increase the length of a sling. It will pull so tight that you'll never get them back apart. I see people do this all the time and the only solution is to throw them away.

Not for crane use (must use shackle for that), but for recovery use, choker hold can be used if you shove a load of grass or a couple of sticks in the choke. These will compress but will also swell back a bit and can be pulled out piece meal. Also softer "upside the head" if sling gives way!

 

[73m819]

Tag line use

When you use a tag line DO NOT wrap it around your hand,
1 -- You CAN NOT get out of it if needed.
2 -- If the tail gets hung up you could end up with a CRUSHED hand.

Tie BIG KNOTS in the handling end for better grip of the tag line, there is nothing worse then a rope BURN from the tag line getting pulled though your hand.

 

[73m819]

The boom flipping over backwards isn't much of a problem with hydraulic cranes, the boom cylinder will prevent this from happening.
You are correct about lattice boom cranes as in the vid though.

Also, the P&H and American cranes you mentioned have a massive amount of counterweight hanging off the back of the house. This also plays a major part in them flipping over backwards when something goes wrong.

I've seen pics of cranes flipped over backwards when they swing over the side with the counterweight installed and the outriggers aren't fully extended.

Not really true, , A hyd. crane WILL go over backwards if the something (rigging, hoist cable) breaks while handling a heavy load EVEN with off side outriggers set, this issue is why rubber tired cranes are required to have ALL outriggers set BEFORE a lift is made, the outrigger will slow down a back flip, but will not PREVENT all back flips.

If the circumstances are right our 5t wreckers will flip backwards over the side if the off side outriggers are not set, it would be real hard to flip if the offside outrigger is set.

I know a lot of this may seem that it does not applies to our use BUT it gives you something to think about, which in turn gets you thinking about WHAT YOU are doing with your wrecker crane, again the whole idea behind this thread is to keep someone from getting hurt and equipment tore up.

 

[m16ty]

Ron, I was talking about the boom flipping over backwards, not the rig.