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On 8/28/2021 at 7:53 PM, Jeroen Ottens said:

The only way to drive eight functions without using three hubs is by using a gearbox. That requires one L motor to rotate a wave selector that is surrounded by four driving rings.

In each position the wave selector engages two clutchgears. By using two motors to drive the functions you can get eight functions with just three motors. 

I used this solution for my cherry picker (M motor for the wave selector & 2 L motors to drive the functions) - it works a real treat. Didumos' 90° limiter came in very handy, of course.

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After being reunited with my bricks I was able to make in bricks what I had been thinking about in my head in the past week.

Here is the reel mechanism:

51425615523_0126dfe887_c.jpg

The reel is the big red rotating spidery thing at the top of the header. In 1935 a patent was filed to keep the tines (that are the vertical sprung wires that stick out) vertical during the rotation of the reel. That has been in use ever since. As you can see the tines (the LBG 3L half liftarms) are all vertical on this reel as well.

The way it works is that there are two hexagons (a red one from the reel itself and a LBG idler hexagon). These two hexagons have a one stud offset. Six cranks are used to couple the two hexagons to each other. The tinebars (or axles in this case) where the tines are connected to are hard coupled to the cranks. By rotating one hexagon, the other is taken along and the cranks stay horizontal during the whole cycle and therefor the tines stay in the same (vertical) orientation during the cycle as well. Easy to understand once you see it working, but I needed to find the patent before I could wrap my head around how this mechanism works.

I made two versions of this, one uses the big turntable at the side. The advantage of that is that the central axle of the reel can pass through the idler hexagon and the drive can be on the outside, like the real thing. However it looks quite bulky and it has a lot more friction, so I decided to go for the better playability. This means that the drive will be somewhere in the middle instead.

I also did some more research on the Terra Trac. On the Lexion there is no 'headland protection', ie the front idler of the track doesn't lift when steering. Instead the whole track pivots around its center point. Now I am in a bit of a pickle. It will be a challenge to create a pivot point that is sufficiently strong to carry the weight to tracks without the tracks bending sideways. Plus I loose the cool lifting mechanism... So I'll give the strong pivot point a try, but if that proves too difficult I'll revert back to a less realistic, but cool front idler lift only.

... trying different pivot solutions... all too bulky or too flimsy...

So here is the 'headland protection mechanism':

51424853062_b2759f9430_c.jpg

The yellow axles are for the steering of the rear wheels and the lifting of the front idler. The steering axle can rotate 90 degrees either way. As a result the yellow 5L beams will be lifted one stud by the black 36T gears independent of the direction it is steered. The black 36T gears are driven. This way the load on the tranversal yellow axles is minimized. The four DBG 9L beams are needed to fix the beam between the front idlers in x,y, Rx and Rz. Ry is fixed by the two 5L beams, so only z is left as a degree of freedom on that front axle.

Edited by Jeroen Ottens
gave up on pivot mechanism and designed lifting idler instead

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Do you have a link to the patent? I would love to fully understand the reel mechanism. 
The lifting mechanism looks complicated, so I like it

Edited by Rebel_Lego

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3 minutes ago, Rebel_Lego said:

Do you have a link to the patent? I would love to fully understand this. Also, maybe you could use a small turntable as pivot point? No idea if that’s strong enough though.

Here is the link to the patent: https://patents.google.com/patent/US20050252188

The small turntable will not work because the grey hexagon rotates on a virtual crank, which means it needs a central hole of at least 3 studs. Which is exactly the size of the hole in a large turntable. I found it really difficult to wrap my head around it, even with the patent pictures.

5 minutes ago, 1gor said:

I really like what I see; I could become envy

Don't be, just copy what you like :laugh:

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On 9/5/2021 at 10:06 AM, Jeroen Ottens said:

 

Don't be, just copy what you like :laugh:

Well, currently all my concentrations is in this little (now 7 week old) baby800x1067.jpg

He is even lighter than my most optimized MOC (he has 700g) but full of energy

Edited by 1gor

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7 hours ago, Jeroen Ottens said:

Here is the reel mechanism

Nice and thanks for the explanation, curious how this will work out!

 

7 hours ago, Jeroen Ottens said:

So here is the 'headland protection mechanism':

 

I wonder where the yellow leftmost axle is planned the be used for....

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7 hours ago, Jeroen Ottens said:

The small turntable will not work because the grey hexagon rotates on a virtual crank, which means it needs a central hole of at least 3 studs. Which is exactly the size of the hole in a large turntable. I found it really difficult to wrap my head around it, even with the patent pictures.

I meant using it as pivot point for the TerraTrac, but since you're dropping that, it doesn't matter anymore

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1 hour ago, GerritvdG said:

I wonder where the yellow leftmost axle is planned the be used for....

That will connect to the steering motor

18 minutes ago, Rebel_Lego said:

I meant using it as pivot point for the TerraTrac, but since you're dropping that, it doesn't matter anymore

Ah, my bad. I indeed tried to use that for the pivotpoint, but that made for a very bulky solution to get it stiff enough.

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34 minutes ago, Jeroen Ottens said:

Ah, my bad. I indeed tried to use that for the pivotpoint, but that made for a very bulky solution to get it stiff enough.

That's a shame. Well, I will watch out for any new progress!

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Time for another update. I have been struggling with the structure of this beast. I like my models to have some internal structure that is strong and sturdy, while using a minimal amount of parts. There should be some logic to it. But in this model I just couldn't get a feel for how this structure should look like. So instead I started to play with panels to get the outer contours somewhat right. Hopefully this will help with fleshing out the inside.

So here is the first attempt at some bodywork:

51454737778_02ff55e7b7_b.jpg

The proportions do not feel completely right yet (the white area is maybe a bit too long).

This thing is going to be massive! I underestimated the size of this thing severely (which also explains why I couldn't get a grip on the design of the internal structure). It is currently 65 cm long, adding the header at the front and the spreader mechanism at the back my guess is that it will be 80 cm long in total. If I would add the biggest header this thing can handle it would also become 80 cm wide *huh*. Which is similar in size as my F14 Tomcat... I may have to add some more functions to prevent it becoming an empty box like the 42100 :tongue:.

The eagled eyed among you may have noticed a big turntable in the track. That is correct, I am reverting back to the pendular suspension on the tracks. This is the only way to get enough room for the actuators to lift the header. As a consequence the diff of the tracks is now suspended and can not be locked anymore :cry_sad:.

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I like where this is going! I can see the overall shape of the harvester coming together. Very nice recreation of that "y" shaped transition from green to white. 

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I think shape is recognizable and what I like particularly using technic panels instead of bricks and tiles only ...

Edited by 1gor

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30 minutes ago, 2GodBDGlory said:

It looks very much like it is farm equipment designed by a supercar builder, in a good way!

:laugh: made my day :thumbup:

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I mean lifting the front wheels of the Terratrac when the model steers. But I agree that lifting the header will require quite some force.
 

A lexion terratrac does not have that feature it’s  to heavy,  a forage harvester have the same weight the hole time, a combine can have up to 18000 L (13 T) in the grain Bunker, plus it’s own weight, which is, depending on header, over 20 T, 

Edited by Meyers technic

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On 9/13/2021 at 4:29 PM, Meyers technic said:

I mean lifting the front wheels of the Terratrac when the model steers. But I agree that lifting the header will require quite some force.
 

A lexion terratrac does not have that feature it’s  to heavy,  a forage harvester have the same weight the hole time, a combine can have up to 18000 L (13 T) in the grain Bunker, plus it’s own weight, which is, depending on header, over 20 T, 

Thanks for the confirmation. I suspected this to be the case, but I couldn't find documentation on this.

And all the others, thanks for the encouragement. Here are some new pics with further progress:

51489236775_2d74b7f22d_b.jpg

The overall dimensions are now more or less fixed I think. I have updated the Y shape, made it a bit smaller and thereby cleaner. It actually is still a bit too big, but I am compromising here between being able to use clean paneling (the length of the Y is determined by the three curved 3x11 panels, but that is actually too long) and following the blueprint to the t.

I have played a bit with different designs for the unload pipe. I first thought to use system 2x4xsomething half-cylinders to build a long pipe, but these are not available in lime. Then I tried to stack these rims: 56145.png, but even with a 32L axle they just sagged under their own weight. So I ended up with the design as shown. That is stiff, but still (relatively) light. I added a folding section at the end. I still have to decide whether or not to make that remote controlled. If so, I'll probably have to go the pneumatic route.

Then I also worked on the folding doors on top of the grain bunker:

51489019829_a71b663a34_b.jpg

I hadn't realised this, but all doors are actually operated through one motor. Here is a video of the real thing:

This also explains why the front and back door have slanted edges. I have a first mechanism operational, but it is not working as smooth as I would like, I think the slanted edges are a bit too much angled inwards and the upper doors are positioned so far to the outside that they interfere with the unload pipe. So I'll be redesigning that part. For now I'll leave it at this and first work on the header lifting mechanism.

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It is beautiful :wub: 

I have no other words; and it's even not finished.

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Not much time lately to build, but here is a quick update. I've worked on the header:

51511287221_6c7c3526ea_b.jpg

as predicted this thing is huge... *huh*. I am running out of lime parts fast with this build. So all the red panels need to be replaced with lime ones. The drive of the reel is in the middle, as I didn't want to use the big turntables at the outside. The chain is a bit too tight, so I may redesign that bit again. Because the drive is in the middle this also gave the opportunity to add an extra lifting arm for the reel. The small LA is located higher than in the real thing, but it is right above the feeder, so I couldn't place the mini-LA below the arm.

Here is a photo of it attached to the combine. It is now so big I can't properly photograph it anymore :laugh:

51510484747_9f29146e68_c.jpg

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20 hours ago, Jeroen Ottens said:

Not much time lately to build, but here is a quick update. 

*Snip*

I like that! Especially the usage of those round 2x2 bricks in the rotating thingy. The fan blades look great aswell. 

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It has been a while, but I finally found some time to work on this one again. I've mostly worked digital now to get a bit of a feel for the interior. Here is a picture without paneling:

51738062268_2bf9f96104_b.jpg

For the eagle eyed among you, there are indeed three Control+ hubs. The model currently has 11 motors to operate 14-20 functions (it depends a bit how you count the harvesting functions). Eight of those are remote controlled pneumatics. The big chunk of gears in the back is the pneumatic function selector. It uses one L motor to select one of four pairs of pneumatic switches. Two XL motors are used to toggle the pneumatic switches. A fourth motor is used to drive two pneumatic pumps in 180 degrees phase.

There is one hub for driving, steering, locking the differentials and switching high/low gear. It uses two XL motors for drive, one L- motor for steering and one L-motor for switching gears & locking the differentials. It basically is a 4 speed gearbox, that has high-gear, high-gear, low-gear and low-gear. The rotation of the wave selector is routed through a 24-12 gear combination. The result is an axle that rotates 180 degree for every 90 degree of the gear selector. This axle is then routed to the mid-diff and the rear-axle diff that each have a waveselector to lock the diff. With a 180 degree input it will alternate between fully open and fully closed. So the gearbox switch-sequence now becomes high-gear, high-gear locked, low-gear and low-gear locked.

The last hub is used to drive all the harvesting functions like the reel, the cutters, the collector drum, the loaderbelt, internal drums, the seeve shaker, the chopped straw spreader, etc. and the fake engine and the huge fan in the back.

Pneumatic functions that I am reasonably confident about:
- lifting the header (2 XL)
- lifiting the reel (2x small thin)
- Extending unload pipe (1x XL)
- Bend unload pipe (1x XL thin)
- open grain silo doors (1x L)
I have still three more switches available that I could use for the following functions:
- Left panel
- Right panel
- Extend ladder
- rotate ladder
If anyone has more ideas for pneumatic functions, let me know.

Here is a view with most of the paneling on:

51737824586_7e26cde40c_b.jpg

In the real machine there are two huge drums that rotate to split the seeds from the straw, however the hubs and pneumatic selector take so much space that these will not fit. I still want to try to get a conveyor belt or something to bring the crop all the way to the back where the straw spreader will be. I hope it will be possible to feed something like small cottonballs through the whole system where smaller ones are moved to the grain tank, while the bigger ones are spat out from the back. It is getting tight inside though (just as I like it :tongue:).

Comments, questions and critique are welcome as usual

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