42042 - Crawler Crane - Mods and improvements

[kolbjha]

I am trying to make a full "clean" RC mod, using the concept for claw operation that I suggested initially in this topic.

Anybody know if it is possible to get any longer LEGO medium string than the one supplied in 42009 (LEGO String 250cm (Medium Thickness) (14728 / 700072))? Alternatively, any idea on how to splice two of them?

Another idea for increasing torque

Yellow #1 connector in the middle should be new 1L beam. Or regular 3L beam)

Tan 5L axles is mounting points for claw mechanism.

BTW, I am trying to use a modified version of Victor Imaginator's idea for added pulley friction for the claw, using two pulleys in stead of three.

I'll hopefully get back with the result, need some time I guess. Meanwhile, I am thankful for any idea on how to obtain a longer LEGO medium thickness string.

Leg godt!

[doug72]

Having built the crawler carne as per Lego instructions, set out to make all six functions independently PF controlled using five M motors and one L motor. One feature I didn't like was both crawler tracks moving together making turns impossible.

First step was to strip out the drive selector gear box and L motor and the original drive to the crawler tracks.

Stage 1: modify crawler tracks

Crawler tracks: driven by two M motors via 18:1 reduction with PF Rx and seperate battery box. (had tried to put two drives through the turntable but not successfull due lack of space.)

Stage 2: modify hoisting, luffing, slewing motions.

Hoisting: M motor via 20/12 step up gears to give faster hoisting speed.

Boom Luffing: M motor via 12/20 reduction gears.

Slewing: M motor installed where L motor previously located - then via a gear chain with 9:1 reduction to give more realistic rotation. Had problem with gears rubbing on the other two M motors but by turning M motors on there side and using a spacer plus a support plate this eliminated the problem.

Stage 3: modify grab to remote operation.

Operating Grab / grapple: operated by an L motor directly coupled to the small linear actuator with power feed to the L motor using a lead extension back through the boom back to the PF Rx.

Two PF Rx installed in the now open space where drive selector gear box was and open spaces filled in.

Battery box installed upside down to hide switch from view.

Fixed end of hoist rope moved closer to the boom head.

See photos on my Flicka page:

https://www.flickr.c...157657223548309

Edited August 23, 2015 by Doug72

[mx2000]

Yes, that is what I meant. You're right about the pulleys, that is why I didn't use any pulleys and connected the cable directly to the central linkage of the grapple. But even then the closing force is small.

I added a central liftarm where the mLA used to be to reduce the degrees of freedom and make the movement smoother. This is how it looks at the moment: (the central grey liftarm can slide up and down)

This is probably closer to how these things work in real life, at least the ones I have seen. These cable diggers usually have two cables, one connected to the interior of the shovel and one to the exterior though some pulley system. The cable does not loop back to the boom though, as far as I understand this (I imagine this would make switching to a different shovel very complicated).

Like this one here (Liebherr calls this a diaphragm wall grabber):

http://www.liebherr.com/CH/en-GB/region-CZ/products_ch.wfw/id-20843-0/layout-PopupTabWide/item-ImageGalleryImage13281_85_5/measure-metric/tab-13281_85

Of course, in real life, these things work because they are extremely heavy (like 10t or more for bigger ones).

[doug72]

There were several of this type of massive cranes in use when they built the 2nd Tyne Road Tunnel, near where I live. The diaphragm wall trencher device also had a large hose connected to it to supply Benonite to stop the exacvated trench from collapsing. In some sections the trench was 30m deep by 2m wide.

1st Tunnel built by boring under the river - 2nd tunnel by cut and cover and submerged tunnel sections in the river bed.

I have one narrow bucket and once get another will attempt to make a diaphragm wall trencher.

Or use the clam shell buckets from the 42043 model.

[LennyRhys]

Meanwhile, I am thankful for any idea on how to obtain a longer LEGO medium thickness string.

It's not unique to Lego - just look for braided nylon string/thread/cord on ebay. Search for the diameter you want (I think that the Lego stuff is about 1mm or perhaps 1.5mm, but there are many diameters available) and you will be able to buy very large quantity for very little money. Some time ago I bought 100m of 1mm braided nylon thread for about €5 and it is the PERFECT size for lego pulleys. :)

[kolbjha]

It's not unique to Lego - just look for braided nylon string/thread/cord on ebay. Search for the diameter you want (I think that the Lego stuff is about 1mm or perhaps 1.5mm, but there are many diameters available) and you will be able to buy very large quantity for very little money. Some time ago I bought 100m of 1mm braided nylon thread for about €5 and it is the PERFECT size for lego pulleys. :)

Thanks, I will try that

Edited August 26, 2015 by kolbjha

[gvo25]

Hello All,

Here's my version of the 42042 crawler crane:

All functions are independently controlled:

- slewing: L-motor. It's still in the same location as in the original 42042

- luffing: M-motor

- hoisting/lowering: M-motor

- driving: 2 L-motors

The boom,the luffing arrangement and the cab have also been remodelled

The crane is still a WIP, maybe I have to add a little bit of counterweight. One batterybox is not enough when there's a load in the hook; the original slewing mechanism doesn't work good whe the boom is leaning forward. Also I still hope to do the motorized grabber, maybe with a shorter boom

[GTRulez]

You guys might want to check out this site, it shows some nice pictures of a real grab operated by using an extra rope. (they also have pictures of diffrent types of grabs)

by the looks of it they use a couple of sheaves/pulleys to increase the power of the grab. the only problem you will have with lego is that the grab is quite lightweight so it might not open as well. because space is tight in the grab you wont be using as much pulley's anyway. these kind of claws/grabs are used in freight ports all over the world.

Link:

http://www.tgs-grabs.nl/products/mechanical-rope-grabs/mechanical-two-rope-orange-peel-grabs/

At my current job site there is also a crawler crane working, its a Liebherr LR1140 that has a Luffing jib installed.

i wanted to make one out of lego for the 42042 so i took some pictures and started from scratch.

it uses an extra motorized winch in the first section of the lattice boom just like the LR1140 wich operates the jib.

i used an M motor wich fits perfectly in the original boom section and a simple winch of the same design used in the model.

there are alot of pully's in the jib to adjust the angle of the jib and to support the hoist cable just like the real deal.

i also added another pully on the main boom to make it a bit stronger (clutch started slipping when erecting the crane) need a longer rope to get the full range of movement though..

i replaced the claw with a simple lego metal hook simular to GVO25 although mine only uses a single rope on the block. the winch of the hoist is strong enough for lifting loads with the Jib.

I'm surpised how stable the model still is with its standard ballast :)

It's still wip but im pleased everything works well.

[efferman]

My first two mods on this model

The pulley pulls now between superstructure and the small boom

And tghe boom sections have no identical mounting points. so the can be mount at eevery position in the boom.

[kisper]

^^efferman : can't wait for the video :)

[efferman]

this could take a long time because i have to build something different till november the fourth

[bonox]

Thanks, I will try that

even cheaper and easier is builders string line. 1.5mm is common around here. 1mm might take more work. I got a few hundred meters in red for half the price above. If you don't like the super bright colours you'd have to dye it, but I note that if you are after a synthetic rope (and not wire rope) analog, those bright colours are actually made for the real thing (http://www.samsonrope.com/Pages/KZ100.aspx)

[kisper]

this could take a long time because i have to build something different till november the fourth

Good things are worth the wait :)

[GBC Master]

Hi everyone,

Here's my fully remote controlled diaphragm wall grabber modification of the 42042 crawler crane (thanks mx2000 for the idea :-) )

I've tried to fit all motors and battery boxes within the dimensions of the original model.

Features:

- Driving: each track is driven by a separate L motor. A second battery box is added for these motors.

- Slewing: XL motor

- Luffing: L motor. This drum has been moved to the back of the crane.

- Hoisting: L motor

- Grabbing: M motor together with the hoisting L motor through a differential. (System mentioned by Cumulonimbus). The weight of the grabber is about 250g. So the pinching force of the buckets can be roughly 2kg

- Rope: 1mm braided nylon

- Working headlights on the cabin

- Second exhaust for extra cooliness

- Spoiler to reduce drag

- Added a couple of sections to the boom

- Used a mini turntable to make the grabber ... turnable

Pictures can be found here (can anyone post the first picture here please? I can't use the image extension yet...)

Kind regards,

Joris ;-)

[bobblehat]

It's not unique to Lego - just look for braided nylon string/thread/cord on ebay. ...........

In the UK you can try to find a Hobbycraft store or similar retail outlet. I bought 10m of 1mm Macrame black cord for £3.00. It works really well on Ultimate 42009.

You can get this Rico branded cord in Black, White, Blue, Red, Purple(!), Lilac and Light Pink (Hmmmmm!). Hobbycraft's code for black is 607591.

Cheers, Bob.

[gvo25]

Hello guys,

To celebrate the new year, I made a second boom on my crawler crane. Here are some pics (sorry for the bad quality) and a 'promotional video' of my crawler crane

[aminnich]

Heys guys, I slowly looking into modding this set. My first objective would be to make it RC, and then make a longer boom. Im wondering if the boom that is on the original model would hold up past maybe 5 sections? And if not, has anymore made a super strong sectional boom for this model??

[Riley-NZL]

Hey guys, This is my first Technic set, and I think it's started a new addiction. I've also never modded, or created my own set before; however I'm looking at buying a second one of these to make some improvements with. Also, sorry in advance, not sure the correct anme for Technic parts :P

A couple small improvements I've made by sacrificing the small (seems strange saying that) yellow wrecking ball crane from the LEGO city set:

Changed the angle of the mast slightly to allow the boom to come up to a higher angle, also removed the 3rd "Wheel" on the winch mechanism as it's kind of redundant. Probably going to get rid of the black ball tie of point, and just tie it straight to the winch beam:

Added an extra pulley set to the main winch, to increase thew winch lift capacity. The pulleys had to much friction, so I changed the three wide pin things to the + profile rod things:

Same on the "hook", also changed the 3 wide pins, to a bit that has one wide pin, and two wide + profile. I need to build a hook at some point :

Used to only lift two of those containers before change this, probably could lift a 4th as well if I had one:

My plans if I where to get a second set would be to increase the main boom by two sections, and build a small luffing jib. Then add the second battery box behind the current one as counterweight, and hopefully extend the body work by the same length. Change the boom lifting pulley to be a floating mast with the pulley moving the mast instead (as shown by Duke).

Vassel, on your luffing jib, have you added another pulley to move the the angle, or is it manually operated?

[nerdsforprez]

I have already posted this.... and I am not trying to be redundant..... but the following applies here, In order to make this video:

it involved playing with 42042 a lot. As you can see, I build the main boom larger. Added two sections. Easy enough right? yea..... but what I discovered is that at 722 grams 42042 could not lift 8288. But it holds it just fine (and more) with the proper counter weight. And... the pulley set-up is strong enough.... as well as the motor. Then what is the real problem? any guesses?

If lifting capacity is NOT restricted by the motor or the pulley system......then what is it?

[Riley-NZL]

I have already posted this.... and I am not trying to be redundant..... but the following applies here, In order to make this video:

it involved playing with 42042 a lot. As you can see, I build the main boom larger. Added two sections. Easy enough right? yea..... but what I discovered is that at 722 grams 42042 could not lift 8288. But it holds it just fine (and more) with the proper counter weight. And... the pulley set-up is strong enough.... as well as the motor. Then what is the real problem? any guesses?

If lifting capacity is NOT restricted by the motor or the pulley system......then what is it?

Clutch gear? How do you know the motor/pulley is not the restriction? I can't see in your video if you have modified the boom lifting winch at all, but I found as stock this is a week point. The weakest point as stock, is easily that it doesn't have enough counter weight, which you seem to have addressed.

[nerdsforprez]

Yea! You are right! I mean.... I can be wrong... but I am almost sure that it is because of the clutch gear. The motor sounds robust and strong when I try and lift the 8288, not slowing in RPMs or anything, but it begins skipping because of the gear. Truth be told, I lifted an 8070 (video on my youtube channel) with the 42009 (my version) with nothing but a L PF motor. Yes, the mechanical lifting advantage was more because I had more pulleys. But about a year ago, when I tried to lift the 8070 with the 42009 stock it failed but only because of the clutch (and the gear ratio is pretty much the same as the 42042). I would be willing to bet if one took out the clutch gear it could lift the 8288.....in fact.... wondering if it has already been done. Going to youtube now.........

[Riley-NZL]

Yea! You are right! I mean.... I can be wrong... but I am almost sure that it is because of the clutch gear. The motor sounds robust and strong when I try and lift the 8288, not slowing in RPMs or anything, but it begins skipping because of the gear. Truth be told, I lifted an 8070 (video on my youtube channel) with the 42009 (my version) with nothing but a L PF motor. Yes, the mechanical lifting advantage was more because I had more pulleys. But about a year ago, when I tried to lift the 8070 with the 42009 stock it failed but only because of the clutch (and the gear ratio is pretty much the same as the 42042). I would be willing to bet if one took out the clutch gear it could lift the 8288.....in fact.... wondering if it has already been done. Going to youtube now.........

Do they make different strength clutch gears? Althoguh taking the clutch gear out might get you more lifting power, it does increase the chance of stripped gears or a burned out motor.

[nychase]

The only different (stronger) clutch gear that I'm aware of is the original clutch's that came with the barcode truck (8479). Instead of a DBG center they had a Light Grey center and had a quite a bit stronger clutch force. Unfortunately, these special gears aren't given a different part number in bricklink so its impossible to buy them on purpose...if you buy a bunch of used ones you might get lucky but you need to buy from a known old technic seller.

[nerdsforprez]

Do they make different strength clutch gears? Althoguh taking the clutch gear out might get you more lifting power, it does increase the chance of stripped gears or a burned out motor.

The mesh of the gears is pretty strong. I don't think that anything is going to get stripped. And yes, it increases the chance of burning out the motor but if one is careful I think they are fine. Perhaps I will try and open up my 42042, change the clutch gear out, and give it a try. All you have to do is be right there when trying to lift anything, if the L motor is stalling, help it with the lift or simply switch it off, change the gear, etc..... no motor is going to burn out with such little time being stalled. In preparing the video already posted, all together, I am sure I contributed to several seconds of stalling the motor.... no damage that I am aware of.

This has me curious though. @philo would be a good resource for this.......how much stalling of a motor does it take to burn out a motor?

[Riley-NZL]

May or may not have bought a second set: