[WIP] Bergmann Swivel Tip Dumper

[hawkwind]

If you do want to use the new differentials, you can buy the 65414 and 65413 parts for significantly cheaper if you buy them in the bricks and pieces section for about 2.00 USD each compared to upwards of 15.00 USD each on bricklink.

[JLiu15]

1 hour ago, hawkwind said:

If you do want to use the new differentials, you can buy the 65414 and 65413 parts for significantly cheaper if you buy them in the bricks and pieces section for about 2.00 USD each compared to upwards of 15.00 USD each on bricklink.

Thanks, I'll be sure to take a look. That's definitely a better deal than BL.

Edited July 18, 2020 by JLiu15

[Cumulonimbus]

Great vehicle choice, I have seen a modified version of this truck with a detachable skip loading bed on the rear:

Once I saw that truck, I started my own MOC, but the pivoting dumper bed of the original truck proved to be very challenging to design in technic bricks. The geometry of the subframe on top of the turntable is crucial: it can't be too high, it must clear the rear tires when pivoting and it is tricky to find a place for the dumping actuator. So far, I haven't found a solution that worked reliably, so I will follow this topic with great interest. Good luck!

[JLiu15]

UPDATE 7/19/20

I worked on the rear section of the chassis for the past two days, and now it's complete. In fact, the entire chassis is essentially complete by now, just missing the attachment for the dump bed and the pneumatic cylinders.

With a large portion of the space in this part of the chassis taken up by two motors and the rear axle, there is very limited space for mechanisms. I think I did a pretty good job utilizing the space that is available, as the compressor and valve for the pneumatic dumping are both located under the motors. The gear train for the turntable is located behind it, which includes a clutch gear. The pneumatics are driven by the C+ XL while the turntable is rotated by the C+ L. The turntable rotates too fast imo and I feel like some more gearing down would help, but there's literally just no more room left. I'll probably adjust the power curve for that motor in the BuWizz app so it doesn't run at full power.

I've put the wheels on to test it, and it drives and steers reasonably fast. The articulation joint, however, is a weak spot - it has a tendency to bend, and the gear connector block by the linear actuators has a tendency to pull out of the pin hole its upper end is attached to when picking up the model by one hand (as the articulation joint bends). I might end up using the bodywork to reinforce that part when I get to that point, as I can't make the chassis any higher right there without compromising the bodywork.

If you have any suggestions for me, please let me know.

Photos:

Edited January 28, 2022 by JLiu15

[JLiu15]

UPDATE 7/22/20

Not much since the previous update, but still some noteworthy progress. I've added the pneumatic cylinders as well as the attachment point for the dump bed, as well as some minor modifications to the front section of the chassis.

The bed will be lifted by 2 11L pneumatic cylinders, which are placed very close to each other. I had to cut corners here a little - I originally tried to do a 5-12-13 triangle for this section, but I realized the beams would interfere with the pneumatic cylinders' ports. I ended up using angled beams but kept the area around the pneumatic cylinders open so their ports and the hoses going to them won't be blocked.

As for the front section of the chassis, I've reinforced the area around the mini LAs for steering. Now the mechanism has much less play in it and the gear connector directing drive to the mini LAs no longer has a tendency to come out of the pin hole it's attached to. The wires in the front have also been rerouted to account for the location of the cab, and the front suspension is reinforced with a transverse link to reduce the side to side wobbling. Additionally, I've also geared down the mechanism for the working steering wheel.

Moving forward, the model is ready for the bodywork. I'll probably focus on getting the bodywork finished before moving onto the dump bed, as I anticipate that to be a huge challenge with all its angles. The body will likely be built with a mix of Technic and System pieces. As for the dump bed, if anyone has blueprints of the real thing or a close-up view of the dumping mechanism please let me know - it's hard to see exactly where the hydraulics are attached on the real thing, and I feel like the bed will end up way too high because of this. Note that the pneumatic cylinders in the pictures can be lower - it's just the elasticity of the pneumatic hoses pushing them up. Still, I feel like my current setup will lead to a lot of compromises. If any of you have suggestions or have pictures that could help me with building this part, thanks in advance!

Photos:

Edited January 28, 2022 by JLiu15

[JLiu15]

UPDATE 7/31/20

Made some progress on the bodywork. The front bumper and the cab are now done, just missing some details. The cab is made with a combination of Technic and System building, with the entire grille being made of System pieces.

I'm liking where this is going. Sure I had to sacrifice some features, such as the opening driver's door, but other than that the bodywork is coming together pretty well. I'm most satisfied with how the grille turned out, as the use of System pieces really allowed me to model its outline well.

I also modified the front suspension a little - it's got two shock absorbers per wheel now and they are mounted more vertically. The bodywork is heavy, so this modification was necessary to prevent the suspension from sagging. Depending on how heavy the dump bed is I may also rework the central joint (e.g. with small turntables) - right now the model tends to lean forward with the wheels on, but I noticed with more weight in the back it gets better.

If you have any suggestions for me, please let me know.

Photos:

Edited January 28, 2022 by JLiu15

[Jundis]

Really like your progress on this MOC! The added shock absorbers on the front axle made me smile :-P

I would prefer openable doors, even in this case you can't use the 3x11 panel there. One suggestion would be to exchance the spaghetti piece on lower front windshield for this piece and then add a black 7L soft axle in the pin whole to give the illusion of the bent wind shield.

Also the 3x1 curved slope in the second window isn't necessary I think. Plus, there will be some sort of air filter in front of this section, so it doesn't really matter...

For stability, maybe you can place the upper connection of the articulated joint (in front of the big turntable) one stud up? It seems on the 42114 there is the same connection which is a little bit flimsy. But this is just guess work here, if its stable during motion, everything is fine.

Keep on the good work, really looking forward to the final model :-)

[JLiu15]

4 hours ago, Jundis said:

Really like your progress on this MOC! The added shock absorbers on the front axle made me smile :-P

I would prefer openable doors, even in this case you can't use the 3x11 panel there. One suggestion would be to exchance the spaghetti piece on lower front windshield for this piece and then add a black 7L soft axle in the pin whole to give the illusion of the bent wind shield.

Also the 3x1 curved slope in the second window isn't necessary I think. Plus, there will be some sort of air filter in front of this section, so it doesn't really matter...

For stability, maybe you can place the upper connection of the articulated joint (in front of the big turntable) one stud up? It seems on the 42114 there is the same connection which is a little bit flimsy. But this is just guess work here, if its stable during motion, everything is fine.

Keep on the good work, really looking forward to the final model :-)

Thanks!

The thing about this vehicle is that there's only a door on the left side. This would mean building the cabin asymmetrically (and perhaps with the left side being less robust than the right) so I decided against opening doors. As for your suggestion with the bent windshield, I could consider that as the black #4 (45 degree) connector that will eventually attach the mirrors has a pin hole right there. However, I'm not sure about the abrupt transition from a smooth edge with curved bricks to a hard edge with the 90 degree connector. The bottom edge of the window in the real thing looks very smooth which is why I used the elbow pieces to "outline" it.

And as for the side windows, in the real thing their bottom edge slopes upwards - I guess curved slopes aren't the best here, but I got plenty of those and didn't want to wait for the yellow #21 and #22 panels from the 42114 to slowly arrive in the Bricklink market (they've been around for years but took this long to finally be available in yellow smh). I guess I could use this piece here, but I don't want it to look like a grille where it isn't. And yes, there will be an air filter right there - note the brown axle sticking out towards the bottom rear of the cabin - that will be used to attach it.

[JLiu15]

UPDATE 8/7/20

Not much since the last update, but I've got a little more bodywork in with the body panels in the area behind the cab. The only things left to do for the bodywork now are the fenders (which will be many 5L beams attached to soft axles) and their rear attachment point, the side body panels around the fenders, and some various details (mirrors, air intake, and exhaust).

The biggest change is that I've redesigned the rear to work with linear actuators. I should've realized this from the start, but pneumatics simply don't have the capacity to handle such a heavy cargo hold - at least with precision. I've made a mock cargo hold to test the dimensions and the load capacity (not shown as it's color vomit), and with 2 LAs geared down a bit driven by the C+ XL motor the dumping function works pretty well.

The model is about 80% complete by now, and I anticipate finishing it in the coming weeks.

Photos:

Edited January 28, 2022 by JLiu15

[JLiu15]

UPDATE 8/22/20

The MOC is finished! The final Bricklink order arrived yesterday, and I was able to finish everything last night. I still need to get custom stickers made, but that should be pretty simple. I'll try to get the photos/video and MOC topic published in the next week or so, before school starts for me in September.

Stay tuned for the MOC topic!