[MOD] 42112 Concrete Truck improvement/modification

[anyUser]

I thought I might start one:

In the Set topic thread there was some discussion if the drum would unload if pushed backwards. At about the same time a small setup at Rebrickable reminded me of an improvement.

I believe that I got a working setup now:

 

 

 

[SNIPE]

Can the cement bucket tilt in order to dump the contents in the official model? not sure how realistic that is compared to a real cement truck.

Edited June 22, 2020 by SNIPE

[Cumulonimbus]

1 hour ago, SNIPE said:

Can the cement bucket tilt in order to dump the contents in the official model? not sure how realistic that is compared to a real cement truck.

Not sure if you are asking how a concrete truck works, but in any case I thought the image below is nice to see.

No concrete truck I know tilts the drum to unload, I think a loaded drum is too heavy to tilt and dumping concrete like that would result in an uncontrolled mess. The drum has two Archimedes screws inside, if the drum spins clockwise, the content is pushed towards the truck cabin, but since that end of the drum is closed, the concrete is continuously being mixed. When the drum spins counterclockwise, the liquid concrete is carried toward the rear of the truck, where the drum has an opening, and is being fed in the chute towards the area where is it is needed. The drum is never completely full: imagine a horizontal line around the top of the truck cabin, that is the maximum concrete level. The screw combined with the variable rotating speed makes precise dosing possible.

 

Edited June 22, 2020 by Cumulonimbus

[anyUser]

2 hours ago, SNIPE said:

Can the cement bucket tilt in order to dump the contents in the official model? not sure how realistic that is compared to a real cement truck.

I haven't seen any hint in the relased set pictures that indicate that the drum can be raised.

However, it might be possible that the cabin can be tilted forward to access the four(?) cylinder engine. The diagonal (light grey) beam could indicate this.

[mpj]

1 hour ago, anyUser said:

I haven't seen any hint in the relased set pictures that indicate that the drum can be raised.

However, it might be possible that the cabin can be tilted forward to access the four(?) cylinder engine. The diagonal (light grey) beam could indicate this.

Mmm no, I don't think the cab will tilt. If so, they had surely shown it on the rear of the box. And I also think the engine is visible between the 2 seats exactly for this reason (no tilting cab).

What is not accurate in this cement mixer is the rear "half pipe" to download cement. It looks like sliding instead of folding in the middle (never seen it in real life).

[anyUser]

On 6/22/2020 at 11:43 AM, mpj said:

Mmm no, I don't think the cab will tilt. If so, they had surely shown it on the rear of the box. And I also think the engine is visible between the 2 seats exactly for this reason (no tilting cab).

What is not accurate in this cement mixer is the rear "half pipe" to download cement. It looks like sliding instead of folding in the middle (never seen it in real life).

I haven't seen a box picture yet.

I didn't download the box pictures as there appeared no more relevant information. The setup of the HOG control for steering prohibits tilting of the cabin.

This is my quick guess for the pipe:

Note that is is attached to the chassis quite low. Therefore folding is not reasonable here.
In the picture above it is obvious, that the chute is fixed at its upper end with a support at the lower. Soem of these are modular so that you can use different attachments:

(Conneting to a 150 mm tube to increase reach. The original chuts is on the right mudguard.)

Edited June 24, 2020 by anyUser
Remark on box picture changed

[anyUser]

Made some progress:

1. Gearbox for drum set up with unidirectional turning when driven from rear axle. There is a ca. 50 cm (distance) lag between forward/backward change and start of rotation. Speed should be OK.

2. Steering axle setup. I believe that I got better steering angle and thus smaller turning cycle.

3. Cabin can be tilted forward, doors can be opened, and mirrors added.

Edited June 29, 2020 by anyUser
200628: pictures updated, 200629: picture update

[anyUser]

The (original) model is missing the funnel to fill the drum:

Also, I am building a second, less colourful version:

Functions are identical to first attempt. I mainly did some cleanup on he chassis. Manual control for the drum has been swapped sidewise. The lower part of the cabin isn't done yet.

(I would prefer to get a drum in white or yellow instead of dark(earth) blue.)

[Rudivdk]

That black version has a nice apparel, looks real heavy-duty. Somehow it looks bigger in this color. Nice work sofar, looks like you've been able to fully reverse engineer this model! I like the little tweaks and additions too, especially the one-direction switch with the wormgear, way better than a ratchet imho!

[anyUser]

I am quite happy with the compact setup:

Gear 'box':

I think that the gear ratio towards the drum is OK: I get 1 revolution per 1.2 m (4') travel. This should be sufficient to demonstrate the principle *). From the video review just posted to the main topic it seems to be 'faster' there.

However, using of the worm gear comes at a cost: When direction is changed between forward and backwards travel it takes ca. 75 cm (2.5') distance before rotation starts.
I calculated that this could be reduced to 45 cm if the new differential (from 42109) would be used instead (because of 28:12 gear ratio)

 

*) I don't think that the 1M beams will be stting in a while ;-)

Edited July 8, 2020 by anyUser
gear box picture added

[Ngoc Nguyen]

I would love to see a ratchet mod in the drive train from the rear wheels!

[anyUser]

Something based on this draft might figure out:

[anyUser]

This should be small enough to fit into the gear box area of the original set:

(Top view, first rear axle on the left, front of chassis to the right,

all red (axle)pins indicate temporary connections that may be used further)

(Bottom view, first rear axle on the left, front of chassis to the right)

Edited July 8, 2020 by anyUser

[anyUser]

This represents the gear box from 42112 truck as far as I recognized from early review videos:

This is my current solution to the ratched (the yellow bit inside) mechanism:

(top view)

(bottom view)

Implementation to my chassis mod:

There is no lag for the drum rotation is direction is switched from backward to forward. My setup now has 1 full rotation for each 50 cm of travel which I consider (too) 'fast'.

[anyUser]

I am done for the moment. Now I would need the drum pieces to test-drive my version. I would like to have those in either white, yellow, or even grey colour without printing:

- drum rotating only one direction (mixing) when driving
  a) wormgear version: drum also rotating when driving backwards
     setup is inspired by https://rebrickable.com/mocs/MOC-44634/2in1/simplebutclever-2-only-one-direction 
  b) "Ratched" version: drum not rotating when driving backwards

- smaller turning cycle by improved steering angle
- axle width is smaller by (ca.) 2 studs, e.g. wheels are not protunding from chassis
- cabin can be tilted forward
- funnel to fill the drum 

Images:

I can't decide on the colour for second truck: I am missing the proper colour of 3x3 half beams with curve for those schemes that I would like to build...

 

[1963maniac]

Are you going to be making building instructions?

[Cumulonimbus]

4 hours ago, anyUser said:

Seeing that bottom view, I wonder how easy it would be to make the two rear axles pendular. It would require some reinforcements in the frame, but gives you the illusion of suspension on the rear wheels.

[anyUser]

On 7/20/2020 at 3:56 PM, 1963maniac said:

Are you going to be making building instructions?

I may consider it after test with drum installed.

On 7/20/2020 at 4:23 PM, Cumulonimbus said:

Seeing that bottom view, I wonder how easy it would be to make the two rear axles pendular. It would require some reinforcements in the frame, but gives you the illusion of suspension on the rear wheels.

I don't think that suspension on a model of this scale is 'necessary'. I prefer having a fake engine.

I am not an expert on suspension. I have currently assembled two set with pendular suspension: 8284 and 42030 (8265 hasn't?). There is more space for realisation. As you can see the two rear axles are next to each other. Thus there is little option - without bigger changes to the drive train - to have anchor points. The last axle alone could easily be done.

For the other one:
Range would be severely limited as the drive for the drum is passing just over the differential. I have mounted gear support to the 5x7 frame - these could be attached to the upper framework instead.
It could be feasible if you omit the differential for these wheel to put the support to the middle of the frame. Engine and drum would be driven by last axle only.

If you would like to have suspension on a concrete mixer, check out the MOC by desert752

Edited July 22, 2020 by anyUser

[anyUser]

The cement drum is a really heavy weight that has to be moved.

I did some test driving with the drum on both versions: Neither of them could turn it.
Gears are slipping:
a) 12 tooth half bevel to 12 tooth bevel
respectively
b) 8 tooth gears that form the ratched
To fix either of them I think I have to add bracings to hold gears in place. As these are deep within the chassis I may have to redesign the whole gearbox.

[sirslayer]

I have a cool mod by using the fender elements from the Lego set 42098 and use them on my Lego set 42112 and add a grille and add a few Lego Power Ups and you get this!!!!! 

 

Lego Technic 42112 fender mod by victormendoza_jr, on Flickr

https://flic.kr/p/2jLjkFc

Lego Technic 42112 fender mod by victormendoza_jr, on Flickr

Man, I do miss this website!!!   I'm back!!!!  

Edited September 26, 2020 by sirslayer

[1gor]

15 hours ago, sirslayer said:

 

Man, I do miss this website!!!   I'm back!!!!  

I hope that you settled important things and you can look forward.

Glad to have you back buddy. 

[sirslayer]

Lego Technic 42112 Cement truck mods 

Sirslayer's update on my current wips..

and tonight I bring out the Cement truck Cab over tilt upgrade and Sariel.pl 4 banger fix. 

Thank you @I_Igor

 

The tilt cab feature wasn't incorporated was a kind of surprise  and only adding a few more elements would added this feature . The whole model id a technic wonder but it did seem to skip on details like side mirrors and on my mod I 've was able to add a dashboard with touch screen on steering wheel for easy internet control of the Cement mixer.. 

Sariel.pl review of the Lego set 42112 noted about the design of the mini 4 cylinder where the yellow colored half bushing were used as pistons and a counterweight 'bushing gray in color was mounted on the opposite end of the axle.. when building the mini engine just remember to flip the axles where the yellow color half bushing is now mounted on the bottom end of the axle. please see picture i've included. The yellow colored half bushing has a rounded edge on it surface and the lift arm that taps the yellow bushing slides off with ease. the gray cap that was included on my set are round and flat with sharp edges which causes the lift arm to drag the axles and seizes your rolling motion..  I recommend to install the yellow bushing as mentioned and also the now the color matches on the engine.... geezz  

Lego technic 42112 mods Moveable Cab and engine hack by victormendoza_jr, on Flickr

..  Lego technic 42112 mods Moveable Cab and engine hack by victormendoza_jr, on Flickr

Lego technic 42112 mods Moveable Cab and engine hack by victormendoza_jr, on Flickr

 

Lego technic 42112 mods Moveable Cab and engine hack by victormendoza_jr, on Flickr

Edited September 27, 2020 by sirslayer

[sirslayer]

And for those who are curious if the Lego 42112 Cement truck can carry dual rear wheels .. I believe it's acceptable as long the axles don't slide out!!!  So this is just an example of a wip in progress 

https://flic.kr/p/2jLPmha

Lego technic 42112 mod dual rear tires by victormendoza_jr, on Flickr

Edited September 27, 2020 by sirslayer

[anyUser]

After Christmas I was motivated and interested sufficiently to improve on my previous versions (drafts). Both mechanism (wormgear respectively ratched) were not robust enough to rotate the drum. I wanted to set up a more solid & strong transmission from drive axle to the function gear box. However I couldn't find a solution that was small enough to fit.

But I got another idea: Use a differential that would accept power from drive train and from (manual) crank instead of gear selector.
From that I could derive several other improvements:
- shorter worm gear set up means that truck has to move less distance before drum starts to rotate (less than 40 cm compared to 50 cm previously).
- Better gear ratio = rotation speed of drum. It is more feasible to replace some of the gears to adjust the 'speed'.
- Secondary drivetrain from gearbox towards rear of the truck & back is not necessary any more.
- Because of that it could be feasible to set up pendular suspension for rear axles as major obstacles are now gone.
 

Left side of leatest cement truck version: The manual crank (red) is blocked from rotating clockwise by the red&white lever. This has the cement drum powered from rear axle. Direction of ratation is clockwise (when viewed from rear side).
To enable the crank you flip the lever up.

This truck version has small turning cycle and tilting cabin.

(More pictures will follow after upload).

[anyUser]

If I may bring this up once more:

On 7/20/2020 at 4:23 PM, Cumulonimbus said:

Seeing that bottom view, I wonder how easy it would be to make the two rear axles pendular. It would require some reinforcements in the frame, but gives you the illusion of suspension on the rear wheels.

After a long pause on this truck I believe that I found a pleasing (to me) solution for the improved truck:

Features are:
- improved steering angle
- motor access by cabin tilt
- drum will turn in same (loading) direction regardless of direction of drive (*)
- truck has been shortened to three axles
- pendular suspension of rear axles
- fill funnel

I did a lot of try - and error construction of the gear setup to drive the drum. I found that the performance of the transmission could only be evaluated when the structure was solid enough to support the (filled) drum for drive tests. Therefore my optimisation cycles took long time. To fit the gear box I used a frame setup that represented previous version:

*) This setup has small(est?) number of gears and is performing very well: You have to put in many 1M beams into the drum before you'll notice the drag when pushing the truck. I am using a switched gear box instead of differential to add the manual drum rotation. This is owed to the pickup from the drivetrain.
The mechanism to get unidirectional drive has been copied (inspired) by this post:

Several pair of gears can be changed to adjust transmission ratio in a) rear wheel drive, b) manual rotation input, c) drum rotation.