Luffing crane - a perfect fit to 42078

[BrickbyBrickTechnic]

Awesome to see the model in action! The functions are more impressive than I thought.

[Leonard Goldstein]

On 17.1.2018 at 10:06 PM, BrickbyBrickTechnic said:

Awesome to see the model in action! The functions are more impressive than I thought.

Hi @BrickbyBrickTechnic,

many thanks! It was quite challenging to make this all work 

 

I know, my last post was a little bit short - only the links to the video and the LDD-file (sorry!). Well most of the structure is not to complex, but I think the engine-house is worth to give some more information. And here it is:

The engine-house consists of three parts:

Red: working section

Green: steering section

Blue: power section

Lets start with the working section. The different colors mark the six function:

Red: winch

Green: rotating the claw - the green structure is a sub-assembly to make it easier to mount the rope (Note: wind to rope 2,5 times around the pulley to produce enough friction !!)

Blue: open/close the claw - the axle is connected to a pin with friction. This keeps the rack in place while this function is turned off 

Yellow: rotating the superstructure - the 8T-gear meshes inside the turntable

Pink: moving the boom using the two linear actuators

Azur: driving on the rails - the vertical axle is placed in the center of the turntable and runs the two winches inside the bridge

Next the steering section. Same colors as before. As mentioned in a post before there are only 4 clutches available in the 42055. Therefore the blue and the green function use an "old school" solution with alternately meshing gears. On the back side you can see one brown axle. This is the connection to the power-section.

And finally the power-section. It consist mainly of the battery box (yellow) and the XL-motor (green). A nice detail might be the friction clutch (blue) which consists of two sprockets 57520 an a tyre 61254 inside. To active the clutch the sprockets are pressed together. This is realized by a moving the motor with the red suspension.

Regards

Leonard Goldstein

[Leonard Goldstein]

Hi everybody,

some more information to the clamp (and maybe an interesting detail concerning a 12:24 transmission):

Lets have a look at the gearing:

And now the clue: the 12:24 transmission (green / red) uses 6589 bevel gears instead of 32270 gears. Why is that?

• The correct center distance is (12+24)/2 = 18 mm
• The real center distance is sqrt(2^2 + 1^2) = 2,236 Stud = 17,89 mm

This means that the very often used 12:24 transmission is an illegal build! A single arrangement is not to critical because of tolerances, but a symmetric arrangement produces a lot of friction:

 

There are some clocks around here in the [TC13] which of course are very sensitive to friction. If a 12:24 transmission is used the bevel gears might help to increase authonomy.

Regards

Leonard Goldstein

[doug72]

1 hour ago, Leonard Goldstein said:

 

There are some clocks around here in the [TC13] which of course are very sensitive to friction. If a 12:24 transmission is used the bevel gears might help to increase authonomy.

Regards

Leonard Goldstein

I have used this 12/24 gear ratio many times without any issues with friction.
The latest was the Mock Perpetual motion GBC which needed two in series to get a 4:1 ratio.
see example

Edited January 24, 2018 by Doug72

[Leonard Goldstein]

7 minutes ago, Doug72 said:

I have use this 12/24 gear ratio many times without any issues with friction.
The latest was the Mock Perpetual motion GBC which needed two in series to get a 4:1 ratio.
see example

Hi @Doug72,

many thanks for your example. Maybe your solutions works also fine because there is only a bearing on ONE side? In my picture there is only one bearing visible but I used bearings on both sides of the gears. 

Well, my clamp is very friction critical because the rope is sliding on the pulleys if there is to much resistance. And it starts rocking when rotating the clamp. But with the bevel gears it works fine.

Regards

Leonard Goldstein

[Bering]

What a great build. Love the functions, beats all the other Lego cranes. I hope someone will make instructions for it. I would definitely buy the 42055 only for this. 

[Leonard Goldstein]

On 27.1.2018 at 7:54 PM, Bering said:

What a great build. Love the functions, beats all the other Lego cranes. I hope someone will make instructions for it. I would definitely buy the 42055 only for this. 

Hi @Bering,

many thanks, I am glad to hear that. 

I also hope there will be somebody make instructions for it (I am to busy the next weeks - sorry!). At least I could add some hints how to lay the ropes as this is essential for the function of the claw.

Regards

Leonard Goldstein

[johanmyst]

There is someone making instructions.  I am busy making the instructions with blueprint for the nice crane, but be patient.

[Leonard Goldstein]

Hi @johanmyst,

that is really great! I hope the quality of the LDD-File is acceptable for this. 

I am still to busy to spend much time on my Lego. But if you have any trouble, please let me know.

Regards 

Leonard Goldstein

[Maaboo the Witch]

Awesome, man! This is a rare model for Technic; the last time we saw something like this was in 8053. Nice use of 42055's parts too.

[johanmyst]

Hi @Leonard Goldstein,

Your LDD-file is very good, but my nephew and I see sometimes missing parts as black pins. This is not a great problem and i can modify the LDD-file. But first make I the instructions usable to build your crane.

An example from a missing part in the LDD-file is by the motor (in your video is it present : 3673 connector peg.

[RussianGuy]

Hello!

I just finished building your wonderful crane. It is really impressive. I did not fully understand its true dimensions from the pictures. It is so huge I can freely drive my 42030 Volvo under it. The rubber tire engagement mechanism is genius and I like the gearbox, the diagonal axle trick is interesting.

I love how modular the crane is, it is a pleasure to connect big parts with “pins with stop bushes”, it feels almost like an official set. I hope someone takes advantage of that in the instructions.

Unfortunately, the actual functions work poorly. The need to constantly apply pressure kinda kills the pleasure and the tire slips nevertheless, making the movement not steady (it is really slow anyway). I understand that there is a lot of friction in the gearbox. The top two clutches are not fixed (old school solution) and constantly get in the way when you don’t want them to, making the friction worse. The fact that these gears are not synchronized does not help either.

The lowermost block with 24 tooth gear is not attached firmly enough. I had to put the blue axle pins or even the 4L axle back in place many times, they are easily kicked out when the movement is blocked down the drivetrain. This mostly happens with boom lifting, not with the rope-driven parts. Maybe there was some solution and I missed it?

The upper part of the diagonal axle construction can be easily misaligned. The two 4L axles which hold two halves of superstructure together are highly stressed and also tend to fall off. I connected them with two axle joiners and an axle which helps somewhat. Maybe that part needs more strengthening?

 

The universal joint has slipped off its 4L axle one or two times under load.

I think two t-shaped beams interfere with engagement of the clutch responsible for boom lifting. The other three are noticeably easier to move.

Edited February 19, 2018 by RussianGuy

[RussianGuy]

As for mistakes in LDD file, there was only one significant mistake. 8L axle with stop should be replaced with 9L axle here 

Also, there were several missing pins and some pins of a wrong type and some pins with no apparent purpose, for instance, inside the gearbox. It is hard to keep track of all of them :)

I added one 3x11 panel to the top of the gearbox, I guess it is supposed to go there, there is a row of black pins for it and it is the last panel from 42055.

Edited February 19, 2018 by RussianGuy

[johanmyst]

The problem of the missing pins is for me a problem in Lego Designer. If I add the pins then the beam does not add to the pins more. Maybe Leo can modify the LDD file.

[RussianGuy]

My main rope, the one that goes to the big drum made of two pulley wheels, has just torn. And I must say it is a huge pain to do the thread routing! Did you use some special kind of reinforced thread? I am using a simple sewing thread.

Edited February 25, 2018 by RussianGuy

[doug72]

Try picture frame hanging cord it’s braided and very strong. Have used 1mm diam.cord it with success on my various  crane builds.

Edited February 25, 2018 by Doug72

[Leonard Goldstein]

Wow, so much traffic here - and I am away from my Lego ... I am so sorry!

I know there are some issues in the LDD-File. As @johanmyst mentioned: some connector pins did not fit properly. I will try to fix this, but I am not sure, if I can manage it. In such a big model there are a lot of tolerance problems. Any hints are welcome 

Now the gearbox:

On 19.2.2018 at 9:57 PM, RussianGuy said:

The lowermost block with 24 tooth gear is not attached firmly enough. I had to put the blue axle pins or even the 4L axle back in place many times, they are easily kicked out when the movement is blocked down the drivetrain. This mostly happens with boom lifting, not with the rope-driven parts. Maybe there was some solution and I missed it?

I know, this is not a perfect solution. I also had the problem, that the pins popped out - but only in one motor direction. The other direction works without issues. That is why I blocked one motor direction (like it is made at the BWE). I will try to find a better solution for this.

 

On 19.2.2018 at 9:57 PM, RussianGuy said:

Unfortunately, the actual functions work poorly. The need to constantly apply pressure kinda kills the pleasure and the tire slips nevertheless, making the movement not steady (it is really slow anyway). I understand that there is a lot of friction in the gearbox. The top two clutches are not fixed (old school solution) and constantly get in the way when you don’t want them to, making the friction worse. The fact that these gears are not synchronized does not help either.

Of course your are right. The motor is really stressed with all this gears and this huge crane needs a lot of power. For the video I used a rechargeable battery (8878) which has a little more power in my opinion. And there is a lot of room for improvements if you skip the restrictions of being a C-model ...

 

The rope:

I used a rope that is similar to the one used in the 42038 and it works fine. But make sure the node of the loop does not move around the pulley in the engine house (as the rope is wound 2,5 times around the pulley). You can improve this a lot by using a rubber tire instead of the pulley and wind the loop only one time around (half a time to be exactly).

The mounting of the ropes is quite tricky. First you should mount the loop and it helps a lot to disassemble the green sub-structure: 

And you should fix the set of pulleys inside the boom. This can easily be done by some cross axles. With this tricks it should be a lot easier to mount the loop. 

 

I hope I could help a little. I will try to fix some of the issues as soon as possible, but be patient please. I am quite busy at the moment ... not much time for Lego 

Regards

Leonard Goldstein

 

 

 

 

[johanmyst]

I have also modified the LDD-file with the real shovels from 42055, the 9L axle and the missing motor  pin.

In blueprint I discover a possibility with the wrong/missing pins. If I ready with the instructions (be patient) I add text to some pages.

I don't know the name, but the legs of the crane are for 90% ready.

The motorblock is part 1 and part 2 ready. I am busy with part 3.

Edited February 26, 2018 by johanmyst

[Leonard Goldstein]

Hi everybody,

this week I had time to make at least a little improvement of my luffing crane: I fixed the lowermost gear block with some additional structure. No big deal, but I hope it will solve some issues.

The LDD-File is updated and the new structure is sub-grouped and color coded (like you can see above): https://bricksafe.com/files/Leonard_Goldstein/luffing_crane/Luffing-Crane_42055-C-Model_by_Leonard_Goldstein_20180323.lxf

I also tried to fix some tolerance issues - but I have not made it , sorry! Sometimes there is a curse on LDD ...

Well, that's it. A new project is coming up. And it is BuWizzed 

Regards

Leonard Goldstein

[johanmyst]

Thanks,

 I am busy with the instructions for your crane. I try to use the modifications in the blueprint file. But i must look in the file what you have changed.

I have the previous LDD version changed with the axle that RussianGuy means. And I have updated the shovels with the real 42055 shovels.  (In your file I see the old shovels)

Repeating wat I say , for the tolerance issues/missing pins i have a simple solution : I add text to the pages.

To do for the instructions: motor: working section,  trailer,  container, lamps, and a little from arms connected to working section.

 

[Leonard Goldstein]

Hi @johanmyst,

many thanks for your work! That sounds like you're almost done 

The last changes should be very easy to implement. You will have to remove some connector pins (as they are replaced by another type) and the color coded parts should fit. Sorry for one more tolerance problem: LDD did not accept a 6558 pin and I had to replace it by a 11214 ...

Regards

Leonard Goldstein

[Garin]

Hi Leonard, great build, building using LDD was challenging. do you or anyone have a guide to the rigging? I tried looking and the photos but it’s not clear.

[Leonard Goldstein]

19 hours ago, Garin said:

Hi Leonard, great build, building using LDD was challenging. do you or anyone have a guide to the rigging? I tried looking and the photos but it’s not clear.

Hi Garin,

great to hear that you also build the luffing crane 

I know the rigging is very tricky and it may take a lot of time to make it work. Unfortunately I disassembled my crane months ago and I am away from my Lego anyway. But I will try to give you some hints.

First disassemble the engine house to get access to the working section (see pictures above). Now remove the green part:

For the next step you should fix the set of pulleys with an axle and some bushes (RED). Now you can mount the rope for the winch. Make sure the rope is long enough (the set of pulleys should almost touch the other pulleys on the top in the upper position)

 

Now mount the loop. Use a long rope (I guess 4m; you can cut the left overs later). Roll the center of the rope 2,5 times around the pulley to produce enough friction. Fix the rope by pressing the 99773 triangle (orange arrow) - you will have to free the rope by moving the triangle later. Now assemble the engine house. 

 

The following picture shows how to mount one of the ropes of the loop. The trick is to roll from the bottom to a fixed pulley on the top, back to the moving pulley and again to the top.

Do the same for the other rope of the loop.

Now you have to close the loop including the claw. The following picture shows how to mount the rope around the pulleys of the claw. Before you knot the two ropes to a loop make sure it has the right length. With the fixed set of pulleys (red axle) the claw should touch the ground. Now cut off the left overs of the rope.

Warning! The node of the loop must not run around the pulley in the engine house. As it is rolled 2,5 times around the pulley it would get tangled up.

 

Finally lets mount the rope for the open/close mechanism of the claw. Fix a rope to the pink bush and roll it around the fixed/moving pulley in the same way like to loop (but use the middle pulleys of course). 

This rope runs through the middle of the claw and is fixed to the 63869 cross block. There is a little counter weight using track elements inside the claw to keep this rope tight. Test the function of the claw by moving the pink part. Adjust the length (and the position of the counter weight) if necessary. 

Now you can remove the axle that is fixing the set of pulleys and don't forget to move the triangle inside the engine house to free the loop. 

I hope this will help you to make this crane work. Good luck 

 

Regards

Leonard

 

Edited November 4, 2018 by Leonard Goldstein
spelling

[Garin]

That’s Leonard that was a great help, all rigged up, will give it a try tomorrow. Thanks again 

for such a well conceived model, when it’s running I’ll start on my Mack Anthem (42078)

[AFOLegofan66]

I really like all the functions in this crane and I might give it a try! I’ll try stud.io with your ldd  file and see where it goes...thanks for the file.