[MOC] Bucket Chain Excavator (DONE)

[doug72]

1 hour ago, ColletArrow said:

How about the Arocs clamshell bucket 18943? Sorry if it has already been mentioned, but I think it has enough of an opening on the 'top' to permit it to empty.

Thanks - have tried that and possible but contents wouldn't drop out until the bucket has started to return when they would fall between the two chains.
As on most machines this area is enclosed so could be acceptable.

Moved the chains to 7L apart to allow bucket fixing.

Another possibility is to use two LEGO Black Beam 3 with Grab Hook (11953 / 19540) side by side and as the pair rotate around the upper chain wheel, balls would fall out from the rear through the gap.
Just need to sort out the connection to the two chains

 

More large chgain links on order.

Edited April 6, 2017 by Doug72
added images

[Gabi_BC]

3 hours ago, Doug72 said:

contents wouldn't drop out until the bucket has started to return when they would fall between the two chains.

closest you can get to the real thing with this solution. Just like with the 42055 bwe, the bucket discharge is not exactly similar to real life operations, but a decent trade-off. I'm guessing you will need a deflector plate to keep the load from discharging onto the buckets below and probably jamming the machine. The clamshell bucket is, i think, the most realistic approach so far.

Edited April 6, 2017 by Gabi_BC

[doug72]

10 hours ago, Gabi_BC said:

closest you can get to the real thing with this solution. Just like with the 42055 bwe, the bucket discharge is not exactly similar to real life operations, but a decent trade-off. I'm guessing you will need a deflector plate to keep the load from discharging onto the buckets below and probably jamming the machine. The clamshell bucket is, i think, the most realistic approach so far.

Will be using the clam shell buckets, couldn't get the other idea to work as they wouldn't hang correctly on the chain.
Bucket contents can fall through between the chains into a hopper and onto a conveyor, if I position buckets on the chains so they don't obstruct each other.
Probably build a MOC of the MAN TAKRAF excavator as shown in early post, the one with with all the cables to raise and lower the bucket arm.
Need to source some larger cog gears for the chains - have plenty 14T cogs.

Looking for some more information / images of this machine.

Edited April 7, 2017 by Doug72

[doug72]

Some Progress !!

It has became apparent I may have to re-evaluate the scale of this MOC. So far have been concentrating on developing the bucket chain ladder and unloading chute.
I have four clamshell buckets but won't order more until I know if my ideas will work.

I now have 200 large lego chain links but this only gives about a conveyor 35 Cm. long for a double chain & using larger chain sprockets. (on order).
So have several options:-

1/. Purchase more chain links. (got beat on a bid for 44 more on eBay by a few seconds !!!)

2/. Use large track links instead and figure away to unload each bucket.

3/.  Use different buckets.

4/.  Build MOC of the Man TAKRAF as intended but with a short bucket ladder and alternative conveyor to catch contents of each bucket.

5/.  Build the smaller model of unknow make as shown by drawing.n

Ideas welcome.

Doug

 

Edited April 10, 2017 by Doug72

[jotta93]

Hi Doug

How about making something like this Faller Bucket Chain Excavator?

I know it's a bit simple to build and runs on tracks but there must be a "road version" of it and it may be a solution for you if you don't want to buy more chains 

Or perhaps a smaller version of this Guntert & Zimmerman Canal Trimmer?

I'm not sure if it qualifies as a BCE though 

Hope I could help!

[doug72]

Thanks for your input, but both would still present a problem in unloading the buckets.

If only I could find a BCE that roates the other way then buckets emptying would be no problem.

I believe some very early types did but I can't find any images.

[jotta93]

It seems that there aren't any that excavate down the slope.

I guess that is so because it would be harder to fill the buckets.

I'll see if I can find something 

[Gabi_BC]

40 minutes ago, jotta93 said:

It seems that there aren't any that excavate down the slope.

Those used in opencast mining can dig both below and above grade

 

Not only that, but you don't need to rotate the buckets depending on how you're digging, like is sometimes the case with BWE's. 

 

Edited April 10, 2017 by Gabi_BC

[jotta93]

33 minutes ago, Gabi_BC said:

Those used in opencast mining can dig both below and above grade

Not only that, but you don't need to rotate the buckets depending on how you're digging, like is sometimes the case with BWE's. 

I've seen this pictures before and perhaps I didn't explain myself properly 

What I ment to say is that in your pictures (and in any other examples I have found) the buckets dig forward on the upper conveyor belt and then return on the lower conveyor belt. You simple change the pitch of the conveyors in order to go up or down the hill, but their relation to the main machine (don't really know how to call it) is always the same. The problem Doug mentions in emptying the bucket remains as the buckets would have to make an upwards turn inside the main machine.

Not sure if made it clearer or more confusing 

The only example I have found in which the buckets dig down the slope is on a dredge excavator as in this picture 

 

 

 

[doug72]

9 hours ago, jotta93 said:

The problem Doug mentions in emptying the bucket remains as the buckets would have to make an upwards turn inside the main machine.

The only example I have found in which the buckets dig down the slope is on a dredge excavator as in this picture 

Jotta, your observations echo mine.
On Floating dredgers the buckets chain rotates the other way and as the buckets pass over the top drive wheel the contents just tip out onto the discharge chutes into spoil barges.
I used to watch the floating dredger at a harbour near where I lived as a child clanking away digging silt from the harbour floor.

I have found a small not very clear image of an "Ekbagger" land based dredger mounted on crawler tracks that may work the same as a floating dredger.

Meanwhile, I am experimenting with connecting each bucket to the two chains so that they can tip forward to discharge balls / contents as they reach the top drive wheel.
This requires adding a counter balance weight behind each bucket so balls stay in place untill the tipping point.

Will post images later once prove workable.

Doug

Edited April 11, 2017 by Doug72
Added image.

[doug72]

Unloading buckets:
I have tested the tipping concept and it works OK.
The bucket is free to swing on the two chains and has a counterweight to keep it tipped back to retain contents when moving.
When leading edge of bucket inside the discharge chute hits the trip pins it empties the contents into a hopper over a discharge conveyor.
See video of the test rig which shows a bucket entering the discharge chute and tripping to allow contents to fall out.

Needs a more refining using larger cog gears and incorporate the bucket ladder.
Will probly turn the panels so smooth side is inside to prevent edges of buckets catching as clearences are tight.
For now I will be using the chain I have available to build the bucket ladder and discharge chute as long as possoble but I will extend it later as more chain is acquired.

Once I have finished building my 2nd BWE so my grand children can see it working I will break it down to use various elements to build the BCE.
It will be long term project.

Doug

[1gor]

Just now, Doug72 said:

Unloading buckets:
I have tested the tipping concept and it works OK.
The bucket is free to swing on the two chains and has a counterweight to keep it tipped back to retain contents when moving.
When leading edge of bucket inside the discharge chute hits the trip pins it empties the contents into a hopper over a discharge conveyor.
See video of the test rig which shows a bucket entering the discharge chute and tripping to allow contents to fall out.

 

This looks promising. 

[jotta93]

Looking good Doug!  Have you settled on which type of BCE you'll build?

[doug72]

29 minutes ago, jotta93 said:

Looking good Doug!  Have you settled on which type of BCE you'll build?

At the moment I plan to build the MAN TAKRAF BCE, with a short bucket ladder that can be extended later once have more chain.
More interesting to model as has several functions plus hoisting cables etc.
1/. Independent crawler tracks - 2 x L motors or 1 x XL with M motor for steering via subtractor unit.
2/. Slewing - M or L motor.
3/. Hoisting of bucket ladder. - M or L motor.
4/. Bucket Chain & Discharge conveyor - XL motor.
5/. Two PF IR receivers.

Build will be in stages starting with the bucket chain ladder, discharge chute, hopper & discharge conveyor.
I will prove this before obtaining more clam shell buckets & chain.

I tend to build /design until get what works best.

[doug72]

Progress undate:-
After much triaI and error with little progress I have abandoned using large studded chain links as there are to many problems,
such as:-
1. catching on other parts.
2. chain links obtained form various sources old and have stretched causing alignment problems with buckets.
3. bucket connection to chain studs prone to failure and tipping arrangment for emptying proved too complictaed and un-reliable.
These chains will be used on future GBC modules.

Instead I will be using large track links with buckets attached without any tipping arrangement.

That means either modifying the buckets or obtaining 3D printed buckets.

Cheapest option is modify the the clam shell buckets as they are available from 13p each + p/p in UK.
This will require two holes or slots in the back of each bucket so balls will fall out the rear as it rotates around the drive chain wheel in same way as the real BCE's.
I will make a jig to do this and use a Dremel drill to cut the apertures.

Currently building the bucket ladder and the drive unit.

PS I now know why Lego stopped making Samsonite gears !!!

Edited April 15, 2017 by Doug72

[doug72]

Progress:-

Bucket Ladder Mk. 1 - failed !
Excessive droop and buckets failing to line up correctly or jam as they enter discharge chute housing.
Rejected.

Bucket Ladder Mk 2
Guide rails installed along underside of bucket ladder. the track links run along this keeping buckets close to the boom arm and aligns them to enter the discharge chute housing. Return rollers still to install along top of boom arm above the yellow panel section to support chain when the arm raised above the horizontal.

Bucket ladder now uses 5L track links with each bucket connected ridgedly to a track link via pin/hole connectors.
Buckets no longer tip to discharge contents - instead once satisfied this works will modify each bucket to empty from the rear as it rotates around the drive wheel.
Hope to install 10 or 12 buckets with a longer ladder.

The red beams are there just for demonstration only to keep end of boom up so buckets can pass OK when testing.

Next step is to install a drive unit using an XL motor which will drive the excavator bucket chain and also the two discharge conveyors.

More improvements required for the discharge chute housing and build in a collection hopper above the first stage conveyor which will in turn transfer onto 2nd conveyor similar to that use on the BWE that can stay still or rotate with BCE as it swings. 

Edited April 16, 2017 by Doug72

[jotta93]

Looking good Doug! 

I don't like modifying LEGO parts but if that's the only solution, go for it 

[doug72]

6 hours ago, jotta93 said:

Looking good Doug! 

I don't like modifying LEGO parts but if that's the only solution, go for it 

Agree not ideal or Lego legal.
I will build it with un-modified buckets to prove workable before deciding if to modify them.
Some minor adjustments to make on the bucket ladder to ensure smooth movement of the chain.
Have opted to use half 5L beams on the bucket attachments to ensure hole with pins stay secure.
This means altering the guide rails so that they guide the the 5L half beams OK - if there was a 3L half beam with 3 pin holes that would work better.

Using the hole with pin is OK but even better would be an axle hole with pin which would make connection to each bucket neater.

Edited April 17, 2017 by Doug72

[doug72]

Bucket Ladder Mk 3 with video:
Bucket chain driven by an XL motor with 8:1 reduction. Mounting of XL motor to improve.
Only four buckets at present but many more can be added.
Bucket ladder can be  raised to 45 degs or lowered to to 45 degs.
Small chain sprocket removed from inside the yellow section as was causing jams - works OK without it.
Guide rails improved to ensure buckets ride smoothly.  Discharge housing enlarged and made more rigid as clearances are tight between side of the buckets and inside of housing to prevent contact.

 

Edited April 18, 2017 by Doug72

[jotta93]

Looks pretty sturdy and reasonably smooth

I have a couple of questions though (which you might have answered before, I didn't bother to look, sorry)

1. Will the conveyor belt be longer? I remember reading something about 35cm but have you managed to aquire more track links?

2. How will the unloading system work? I can see that the conveyor belt leans upwards but do the contents of the buckets fall onto another conveyor or do they drop directly into a mining truck for instance? In the image you posted above it isn't clear and I couldn't find an answer from what I've searchched. (I'm assuming you'll base your creation on the TAKRAF ERs 500)

[doug72]

35 minutes ago, jotta93 said:

Looks pretty sturdy and reasonably smooth

I have a couple of questions though (which you might have answered before, I didn't bother to look, sorry)

1. Will the conveyor belt be longer? I remember reading something about 35cm but have you managed to aquire more track links?

2. How will the unloading system work? I can see that the conveyor belt leans upwards but do the contents of the buckets fall onto another conveyor or do they drop directly into a mining truck for instance? In the image you posted above it isn't clear and I couldn't find an answer from what I've searchched. (I'm assuming you'll base your creation on the TAKRAF ERs 500)

Still a few glitches to sort out but getting there.

The conveyor belt
This can be made longer but at the moment it will stay as built until proved and installed into the main body of the machine.
As I am now using the 5L track links (instead of the studded links)  - I have plenty to elongate the chain belt.
The length of the chain belt will depend on its weight of the bucket ladder and the counter-balance required to keep the machine stable.

I may widen the discharge housing by 1L to give more clearance for buckets as they pass through, as they are tending to catch on the slightly raised lip around the pin holes on the 11L x 5L panels. Panels are 7L apart / buckets are 7L wide !!

I am basing it on the Man Takraf as shown in an early post.
http://www.takraf.tenova.com/product/bucket-chain-excavators/#bucket-chain-excavator-ers-500-in-bulgaria

Unloading of buckets.
At the moment they won't be able to unload but once everything is functioning OK I will probably have to modify them to discharge from the their rear via ball size holes.
Would be much easier if chain rotated the otherway !
Contents will drop into a hopper and then either slide down a chute or use a short conveyor to discharge onto the conveyor system as used on the BWE 42055.

Doug

[Hay Ewe]

Enjoying following this project because it is not normal, not a car, not some robot thing from / for robot wars and (attempts) to copy something in the real world.

Good Work!

 

[doug72]

8 hours ago, Hay Ewe said:

Enjoying following this project because it is not normal, not a car, not some robot thing from / for robot wars and (attempts) to copy something in the real world.

Good Work!

 

Thanks for the comments and the encouragement.
At times it can be frustrating trying to get it working but as an ex engineer I enjoy the challenge of problem solving.

Need to improve the discharge housing to replicate the real machine better - its a long term project which will use componants from the BWE 42055 set.

PS:  I too am not into cars or robots but enjpyed watching the final of Robot Wars on BBC last Sunday where the winner decimated every other robot and the arena !!

Doug

[LucyCol]

Starting to come together Doug, Reminds me of a trench digging machine we tested for the Army in the Mid 70's, never could get it to work as it would insist on dumping the spoil back into the trench.

[doug72]

1 hour ago, LucyCol said:

Starting to come together Doug, Reminds me of a trench digging machine we tested for the Army in the Mid 70's, never could get it to work as it would insist on dumping the spoil back into the trench.

Was it like the machine in the bottom left of this page.

Still trying to perfect the bucket ladder and still to decide how to unload buckets.

Once OK the rest of the build should go a lot quicker by modifying the BWE  track unit, base and rotating upper section and conveyors.

Doug

Edited April 20, 2017 by Doug72