42131 Cat D11 Mods and improvements

[westphald]

48 minutes ago, thor_64 said:

I don’t expect to be able to take this project much further for a while so I found this thread and figured I would post this. I have some experience working with actual D11s and wanted to improve the roller frame.  Main differences are linking the front and rear idler‘s with the rollers and adding one more set of rollers.  It ends up being two studs longer, which when I scale out the actual machine is probably a little closer to correct anyway.
The next steps in this project would be converting it to high drive and suspending the front end from an equalizer bar (versus being rigidly mounted).

 

https://www.flickr.com/photos/195025644@N08/51864855927/in/datetaken/

https://www.flickr.com/photos/195025644@N08/51866475150/in/datetaken/

https://www.flickr.com/photos/195025644@N08/51865826801/in/datetaken

 

 

I've been working on adding additional rollers and a roller assembly, as well, but with minor bogies and without extending the overall frame. I'm hoping the design I'm working on will also improve roller stability. Unfortunately, I'm having a hard time adding major bogies into the design, as you have.

I'm still concerned about the strength and stability of the track tensioning setup. It's so wobbly, I question if it's even a good idea to put more load on it by attaching the front roller assembly to it. Have you made any improvement to that?

I'd like to see how you achieve the equalizer bar. I believe @efferman was also working on that.

Edited February 6, 2022 by westphald

[thor_64]

On 2/6/2022 at 11:19 AM, westphald said:

I've been working on adding additional rollers and a roller assembly, as well, but with minor bogies and without extending the overall frame. I'm hoping the design I'm working on will also improve roller stability. Unfortunately, I'm having a hard time adding major bogies into the design, as you have.

I'm still concerned about the strength and stability of the track tensioning setup. It's so wobbly, I question if it's even a good idea to put more load on it by attaching the front roller assembly to it. Have you made any improvement to that?

I'd like to see how you achieve the equalizer bar. I believe @efferman was also working on that.

I have not made improvements to the track tensioner.  I think the pivot point of the major bogie places the idler high enough to place more of the load on the center four rollers, but will only know more when I would have the roller frame supporting the dozer.
 

I just have the end 1/3 of the e-bar built to see if I could get the ball joint in the roller frame to meet with it and I wanted the test the side to side flex joint in case that is needed.

You can see all three pictures, right?   

[westphald]

The second link is 404, but I can navigate the album from the other two. I see what you are doing. Is that going to clear the chassis?

Is that setup necessary? I was thinking of just letting the equalizer bar absorb the flex or suspending it from the track frames with a pair of rubber connectors on each end. You've used the rubber connectors on each end, but with a bit more framing than I was thinking.

It also occurs to me that the equalizer bar could take the majority of load when the blade is tilted back, so might need to be fairly robust.

[Bartybum]

@thor_64 I'd be very interested to see your design working in a video :O It's very cool

[thor_64]

On 2/9/2022 at 6:29 PM, westphald said:

The second link is 404, but I can navigate the album from the other two. I see what you are doing. Is that going to clear the chassis?

Is that setup necessary? I was thinking of just letting the equalizer bar absorb the flex or suspending it from the track frames with a pair of rubber connectors on each end. You've used the rubber connectors on each end, but with a bit more framing than I was thinking.

It also occurs to me that the equalizer bar could take the majority of load when the blade is tilted back, so might need to be fairly robust.

I expect to rebuild a significant amount of the lower part of the chassis to provide a proper equalizer bar mount.  

I plan to mount the rear of the track roller frames to the chassis in the same location that the rear of the blade pusharm connects now.  The equalizer bar will used to support the front of the track roller frames.  The equalizer bar will pivot at its connection in the center of the chassis; therefore its ends will travel in an arc.  There will probably be enough play in the system to allow the track roller frames to freely travel up and down even though they are needing to move slightly inward, but in case there needed to be some forgiveness I created the linkage with the rubber connectors to allow the end of the equalizer bar to "extend" as necessary.  The rubber connectors are not carrying any vertical load - they are only trying to keep the equalizer bar at its nominal length.

Yes, the equalizer bar will need to be fairly robust.

 

[trinitechnic]

Recently bought the set but haven’t had a crack at it yet.

Is it possible to transmit the drive from the staircase rotation to instead power ripper angle?

Also, @efferman, how is your mod going? I’m very interested in moving the drive motors to their correct position.

[efferman]

4 hours ago, trinitechnic said:

how is your mod going? I’m very interested in moving the drive motors to their correct position.

Sorry, no progress till now. There is unfortunately no time for a big project like this. Actually i have the next suction excavator with deadline on the table.

[westphald]

@thor_64, I was taking another look at your design as I continue to work on mine. I didn't appreciate before how much modification you've done to the roller frame and some approaches I would have never considered. Do you have any updates? I like the idea of using a ball-joint for the e-bar mount. Given their friction, I've considered them to be pretty much useless for anything other than robot models until now.

My efforts are, so far, just a bunch of good ideas that haven't come together to something that can actually be built. I'm mostly modeling on Mecabricks, so have little idea of how good the designs will be once built.

Edited March 24, 2022 by westphald

[thor_64]

On 3/23/2022 at 11:02 PM, westphald said:

@thor_64, I was taking another look at your design as I continue to work on mine. I didn't appreciate before how much modification you've done to the roller frame and some approaches I would have never considered. Do you have any updates? I like the idea of using a ball-joint for the e-bar mount. Given their friction, I've considered them to be pretty much useless for anything other than robot models until now.

My efforts are, so far, just a bunch of good ideas that haven't come together to something that can actually be built. I'm mostly modeling on Mecabricks, so have little idea of how good the designs will be once built.

I have not.  If I get any time to work with LEGO projects it is just for a month or two in winter.....so unless I can sneak some time at some other point it will be the same for a while.  I think think the ball joint should work well for this.  Nice tight fit to avoid slop issues and the weight of the model overall will be able to move the joint without issue.

[nugnug115]

The journey is finally over , my D11T dozer is complete , includes 2 hubs , 7 motors and 8 linear actuators. Functions are adjustable blade height and tilt , adjustable ripper height and tilt, deployable ladder and individually powered tracks powered by the top sprocket 

 more on my flicker https://www.flickr.com/photos/189622728@N07/

 

 

Edited April 16, 2022 by nugnug115

[Foes86]

incroyable, j'adore votre montage. Il est tellement plus beau/réaliste

 

Did you integrate a suspension on the tracks?

Edited April 22, 2022 by Foes86

[Aris]

Hello! For me switching system between the 4 functions needs change.

Edited May 7, 2022 by Aris

[nugnug115]

On 4/22/2022 at 1:15 PM, Foes86 said:

incroyable, j'adore votre montage. Il est tellement plus beau/réaliste

 

Did you integrate a suspension on the tracks?

unfortunately there is no suspension anywhere on the tracks , since the weight of all the added parts was bending the original frame of the model i had to reinforce the track frames and the undercarriage to fix this issue 

[SNIPE]

I Finally got around to modding this set, though I built it from parts that I already owned, parts that I don't own are in a pick a brick order that is being shipped. So, for now some parts are substituted.

Originally I only wanted  to make this set just have a single motor per function,

But I figured that its better in this case to just put a motor per side for everything and then leave room in the middle for the driveshaft.

So now:
The ripper blade up/down has 2 C+ L motors
The ripper blade forward/backward has 2 C+ L motors

Then everything else is as planned, with:
2 C+ L motors for the front shovel up/down
2 C+ L motors for the shovel angle adjustment
1 C+ L motor for the Left track tensioner
1 C+ R motor for the Left track tensioner
1 powered up M motor for the ladder
and since I only had 1 C+ L angular motor (from set 42114) and not 2, I used 4 robot inventor medium angular motors linked together with knob wheels.

So in total 15 motors! 😮

Here is the WIP so far:

I intend to power this whole thing via 3 or 4 buwizz 3.0, which I also need to purchase, the model has space for them already as well as space for the v12 engine, so for now i'm using 2 C+ hubs and then I ran out of AA batteries so I used a robot inventor hub (but i've still ran out of ports because there are 15 motors 😮.

I couldn't find a way to simply control all of these hubs from one app (thanks a lot lego you morons)
And pybricks just plain sucked so making a video of the functions, without buwizz is going to be almost impossible, you can't even have motors running and then switch to another app (e.g, the camera) with lego's stupid powered up app, and that app also does not recognize the robot inventor hub.

Regards, Snipe

Edited November 24, 2023 by SNIPE

[Ngoc Nguyen]

19 minutes ago, SNIPE said:

Originally I only wanted  to make this set just have a single motor per function,

You can check my 42131 PF Mod. I managed to do that with PF motors.

[SNIPE]

10 minutes ago, Ngoc Nguyen said:

You can check my 42131 PF Mod. I managed to do that with PF motors.

I actually was using your instructions , to get the extra 2 actuators in the right place

I actually built a little too much of the PF version and wasted an hour and a half but oh well 🙂

I still wanted 4 motors for the two front shovel functions and had already built the 4 - motor rear axle

Edited November 24, 2023 by SNIPE

[grum64]

And there was I thinking the out of box build was complex