terex 4792 LMI question

6t56

Member
I'm looking at buying a terex 4792,it has the ATB wire running along the outside of the boom.I'm obviously going to have to eliminate this wire,like i did on my other crane because the first pick will rip it in half.My question is,does this wire tell the display how many feet of boom is out?And before the safety police tell me how unsafe it is not to have an ATB,i would like to tell them that cranes have not always had those and if you've always ran one without it and your aware of it,it's not really an issue.So can we please just stick to my question.
 

Courierguy

Active Member
Your external cable running down the boom does two things: it keeps the LMI informed as to how much stick you have run out, and it also tells the LMI that you are attempting (or not) to two block your load line. A load sensor in the base of the boom senses the weight, actually the pressure, and combined with how many feet of boom and the angle, converts that into how much load you're picking.

I had two Terex boom trucks with this system, and when you snag that cable on a branch, and do not rewind it properly onto the takeup reel, you can be ALL screwed up! My current Manitex 22101S, bought used, had the factory LMI inoperative. I got it for 4 K cheaper, and then went out and bought a CraneSmart load cell and ATB. Both are wireless, so I was able to do totally away with the original system. The load cell read directly, a much simpler way to go. I make a pick, after I look and see how much boom I have run out(no digital readout, I just look at the boom markings, A,B,C etc), at the boom angle (though that is a CraneSmart option, wireless boom angle display on the same screen as the other info) look at my load chart if need be, and proceed. I love it, it is super accurate and I NEVER have to worry about snagging that damn cable anymore. Expensive, but worth it. Great after the sale service also BTW.
 

classictruckman

Well-Known Member
I second crane smart systems, however I'd call them to see if the could retrofit an internal boom length wire and a wireless A2B system, thats what manitex uses on their new units.
 

Courierguy

Active Member
I should point out that my CraneSmart depends on me knowing how to read the load chart. In other words, I have no automatic cutoff features, just a very loud horn, right by my ears, that goes off if I two block. If it does go off, the immediate response is to put both hands over my ears, thus taking my hands off of the controls, so semi automatic I guess.

The CraneSmart has a lot of features I have not fully explored, I know it can be relayed to the winch and boom out relays at the base of the Manitex so that I COULD have auto shutdown as far as two blocking. I just have not quite got around to it yet. Over capacity, I'm on my own gotta read the chart.

Having had boom trucks with NO LMI, and some with a fully functioning state of the art LMI, and now the CraneSmart system, I am very comfortable.... it is 90% of the factory LMI, and with much less to go wrong. Yes, on some bigger picks, I may pause for a second as I am getting further out with a load to check my load chart, and glance at my boom angle, but knowing the weight of the load exactly, which is what is does so well, is more then half the battle, the rest is up to me. I like the new Manitex system, but not sure It'd be worth the trouble to upgrade to it, but anything is better then having that damn cable on the spool running down the outside of the boom!
 

6t56

Member
So,if i bypass the ATB wire i won't even be able to see the weight of the pick?
I didn't think about that.Well,i guess i'll call crane smart now,i've talked with them before.
 

6t56

Member
[ QUOTE ]
I second crane smart systems, however I'd call them to see if the could retrofit an internal boom length wire and a wireless A2B system, thats what manitex uses on their new units.

[/ QUOTE ]

I'm not sure if you can put an internal wire in a boom that wasn't made with one.But even if you can I know it costs at least $10,000 to pull a boom apart to do anything to the inside.If the cranesmart is around that same price,and i think it is,i'll probably go with that.It's good to know that you guys have had a good experience with cranesmart.
 

6t56

Member
I just talked to howard at cranesmart.He emailed me a quote for each part of the system.If i want to have a full LMI system,i would have to get the boom length indicator which is an external cable but doesn't run all the way to the tip.Here's what he said about it.What do you guys think?


Yes, boom length is measured with an external wire. It is 3/32" diameter aircraft cable( not coax. as there is no power current running through it) The wire has over 1000lbs breaking strength. Also if your boom extends and retracts proportionally, with a single lever. You only have to extend the cable to the end of the first extending section. leaving the remaining 2-3sections wireless.
 

classictruckman

Well-Known Member
that would be good if you only had to attach the wire to the first extention.

The way the internal wire works on our manitex is that the reel is right at the butt of the boom with the wire attached to the final extention, but the closest end so there's no tearing the boom apart to attach it, you just need a small hole to thread the wire through and crimp it.

the National boom trucks just run the wire the opposite way down to a small sheave on the butt of the boom and attach it the same as a manitex.
 

6t56

Member
James,I'm not sure I follow.When you say the butt of the boom are you talking about where the winch is?How would you get the wire inside the boom from back by the winch to the last section of boom,without taking it apart?
 

classictruckman

Well-Known Member
I can't say exactly because I'ven never been quite that close to a 4792, but most boom trucks that I've seen have a sheet metal cover on the back of the boom or are open, so if I'm right you could just modify the cover to get the wire through.
 

6t56

Member
oooooh i see what your saying.Unfortunately the terex's and the national's are completely closed off.I don't know why they do that,it's the stupidest thing they could possibly do,because obviously if the cylinder inside the boom needs repacked you have to pull the whole thing apart=BIG MONEY.The 15 ton crane i have right now is like your saying with the boom open at that end.
 

classictruckman

Well-Known Member
Here I found a picture that may explain it a little better.

You can see the wire runs the opposite way back to a sheave, now the great thing about national s that they actually run the cable right to the tip inside the boom which means they don't need a radio A2B(hard wire is alot less annoying).

 

Attachments

classictruckman

Well-Known Member
Wow completely closed off you say, that is pretty stupid.

Do you know if there are any inspection plates on the top to gain access? it might be possible to drill a small hole in the plate and run it to the final extention if you can get into it to attach the cable.
 

6t56

Member
I don't know,but i'll be trying to figure out some way to do it.Do you know what year that 800D in your picture is?I'm pretty sure i've seen 800D's with no visible wire at all.Like it goes into the boom right behind the reel.
 

mughal88

New Member
Hello everyone. i was searching for the LMI systems and came across this forum and found quite much.
i would like to introduce myself here first. I am a mechanical engineer and we run a business of manufacturing, fabricating material handling and earth moving equipment.
the business is currently being run by my father and i am learning and creating new innovations in the work.
my father have never used this LMI technology in the crane manufacturing and neither i know how to improvise it in the system.
Can anybody would like to tell me how to incorporate this system such that when the crane is at wrong angle and length, it does not lift heavy load, thus bending of causing the boom to fail.
i read above that cranesmart system is good and working. but we in pakistan can only import the components. what i actually want is to someone guide me how shall i install this system and what parameters to keep in mind.

there are also pressure transducers. how does that work ? in the main cylinder. ?

i would be so thankful .
 

brushbandit

Member
I'm looking at buying a terex 4792,it has the ATB wire running along the outside of the boom.I'm obviously going to have to eliminate this wire,like i did on my other crane because the first pick will rip it in half.My question is,does this wire tell the display how many feet of boom is out?And before the safety police tell me how unsafe it is not to have an ATB,i would like to tell them that cranes have not always had those and if you've always ran one without it and your aware of it,it's not really an issue.So can we please just stick to my question.
I'm not sure that you obviously need to replace the ATB wire. I have run my 4792 with the PAT LMI system with the external ATB cable for the past 10 years and have only broken the cable once. I personally would not even consider the added expense of eliminating the external ATB. When a branch does get caught in the cable I can move the crane to get the branch off the cable and lowered.
 
Hello everyone. i was searching for the LMI systems and came across this forum and found quite much.
i would like to introduce myself here first. I am a mechanical engineer and we run a business of manufacturing, fabricating material handling and earth moving equipment.
the business is currently being run by my father and i am learning and creating new innovations in the work.
my father have never used this LMI technology in the crane manufacturing and neither i know how to improvise it in the system.
Can anybody would like to tell me how to incorporate this system such that when the crane is at wrong angle and length, it does not lift heavy load, thus bending of causing the boom to fail.
i read above that cranesmart system is good and working. but we in pakistan can only import the components. what i actually want is to someone guide me how shall i install this system and what parameters to keep in mind.

there are also pressure transducers. how does that work ? in the main cylinder. ?

i would be so thankful .
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