[MOC] Bucket Chain Excavator (DONE)

[LucyCol]

Just now, Doug72 said:

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

Similar, this was designed to be mountable on the back of a standard Bedford MK, I've search but can't find any photo's but then only 2 prototypes were ever made and destroyed when the project failed

[doug72]

After much building & re-building I am finally satisfied with the Mk. 4 version.

The down cutting angle can be increased by adding extra links, if use too many the chain links can slip on the drive sprocket when ladder raised.
Once installed onto main body of the machine I will probably extend the length of the bucket ladder by adding 5L x 7L frames and track links and add more buckets.

Next step is to continue building the BWE 42055 and then modify it to take the bucket ladder instead of the bucket wheel.

Ultimate aim is to have all functions powered - tracks - steering - slewing and conveyors.

I will wait until all completed before attempting to modify buckets to discharge from the rear.

Edited April 21, 2017 by Doug72
remove image file names

[jotta93]

It's coming along pretty well, it has a pretty good digging angle. 

The rest of the excavator should be fairly easy to assemble if you build it from 42055

[doug72]

Bucket un-loading:
Finally figured a way to unload balls from the buckets without ANY modification.
At the moment works OK when bucket ladder is in the lowered position - needs a bit more refining so that it will work at any angle between horizointal and lowered positions.

Balls will fall off the front of each bucket into a hopper feeeding the discharge conveyor.

Hint: no tripping mechanism required and automatic in operation without any power input.

More wil be revealed tomorrow !!

Doug

Edited April 23, 2017 by Doug72

[1gor]

Nice progress 

[doug72]

Previously the guide rails for the bucket chain ended at the pivot point for the bucket ladder.

Now extended these beyond the pivot point so as the bucket ladder is lowered the end of the guide rails within the discharge chute rise - aligning the guide rails - so that the buckets remain in tilted back position retaining the balls.

 

As bucket chain passes over the end the guide rails the chain droops before reaching the drive sprocket, allowing each bucket to tip forward enough to drop the balls into the hopper below.

 

Still refining to get the best range of operation when in bucket ladder is in lowered by altering the axis of the drive sprocket wheel / chain length etc.
 

Probably won’t work when bucket ladder horizontal.

Edited April 24, 2017 by Doug72

[jotta93]

That is a very clever idea 

I had thought of something similar, but it involved extending the actual chain so that the buckets would face down

Can't wait to see it in motion

[doug72]

2 hours ago, jotta93 said:

That is a very clever idea 

I had thought of something similar, but it involved extending the actual chain so that the buckets would face down

Can't wait to see it in motion

Thanks - your comments are helpful - have shifted drive sprocket position and added a smaller sprocket above the ladder pivot axis which allows chain to sag in between when ladder is raised keeping chain engaged on the drive sprocket.
Going to shift the ladder pivot axis inside the discharge housing - think that will also help.

At the moment its a lot of trial and error getting the best arrangment location for the drive & guide sprockets to give a wider operating range.

Looks like it will function best when the ladder is lowered into cutting position.

Doug

Edited April 24, 2017 by Doug72

[doug72]

23 hours ago, jotta93 said:

That is a very clever idea 

Can't wait to see it in motion

Video of balls unloading automatically without any modification to the buckets.
Balls loaded by hand only for demonstration video.
Driven by an L motor with 24:1 reduction.
Chain is a little bit jerky, hope to improve this - somehow.
Next step is to build a hopper to catch the balls to roll down onto the discharge conveyor.

Time to clean up my Lego working table full of discarded parts from many failed attempts !!!!

Doug

 

Edited April 25, 2017 by Doug72

[jotta93]

I'm sure you have alread thought of doing this, but you could anchor the driving axel using an Axle and Pin Connector Perpendicular with Center Pin Hole (part 32184) on each side and put an axel running through a few 2L round connectors (part 62462) so that the upper chain wouldn't be so saggy.

These are quite simple but they should work and reduce the jerkiness

Edited April 25, 2017 by jotta93

[doug72]

8 hours ago, jotta93 said:

I'm sure you have alread thought of doing this, but you could anchor the driving axel using an Axle and Pin Connector Perpendicular with Center Pin Hole (part 32184) on each side and put an axel running through a few 2L round connectors (part 62462) so that the upper chain wouldn't be so saggy.

These are quite simple but they should work and reduce the jerkiness

The driven sprocket axle is supported by pin w/hole connectors for ease of trying different positions for the drive sprocket while testing - can be changed to p/n 32184 once satisfied.
Chain sag on top chain run allows for buckets to pass clear beneath upper part of housing  - which can be modified OK.

The upper and lower runs of the chain within the housing are tight especially as each bucket reaches the end of the guide rails and empities its contents.
Have tried an long axle through the pin holes in 5L x 11L panels with 2L pin connectors to support  and also tried small sprocket  to keep chain runs apart.
Think I have found the best location for this axle now.

Removing or adding one chain link alters the sag considerable.
Remove one chain link and its too tight and angle that ladder can be lowered is reduced.
 Add a link = more angle but a slack chain.

Part of the problem is due to slack chain as it passes around the return sprocket before the bucket enters to guide rail.
Going to try a chain tensioning device I used during my Gyro Tiller MOC, using two shock absorbers with soft springs.

Edited April 26, 2017 by Doug72

[doug72]

Problem solved:-
Added two guide rails ( yellow 3L x 7L bent beams) to support the upper chain run within the discharge housing and has had the added effect of no longer requiring a chain tensioning device.
Cutting angle is good at approx 40 degs.

Now working on collection hopper and transfer conveyor.

Edited April 26, 2017 by Doug72

[doug72]

Now tested for prolong run and working exactly as I envisaged. 

Tidying up the build and have settled on a hopper and discharge chute to feed the discharge conveyor.

Buckets can hold up to five  Lego balls and empty OK into the hopper / chute without requiring any trip mechanism.

L motor re-positioned and better braced.

 

A way to load balls has yet to be investigated.

 

Only thing I would like to change is the 5 x 11 angle yellow panels to grey but they do not appear to be available.

More buckets are on order which will give 8 or 10 if I lengthen the bucket ladder.

Next step is to modify the BWE base to include 2 x XL motors, a PF Rx and battery box. - then sort out how to mount the bucket ladder unit onto the rotating upper part.

 

Edited April 28, 2017 by Doug72
removed Flicka image info.

[jotta93]

I'm curious on how you're going to mount this on the BWE base.

But I'm sure you're going to find a clever way to do so, as you have done from the start with this project 

[pyro690]

Why not turn the buckets around so it scoops up instead of scooping down?

[Saberwing40k]

It already scoops up. The bottom of the chain arm is the digging side.

[doug72]

6 hours ago, jotta93 said:

I'm curious on how you're going to mount this on the BWE base.

But I'm sure you're going to find a clever way to do so, as you have done from the start with this project 

So am I at the moment ! 

Will install motors etc. into the base and then modify it install the bucket ladder unit. I may have to lower the existing BWE discharge conveyor a bit or use a short conveyor instead of the of the chute if it is too low.

Then build the support tower with hoisting system to raise and lower the bucket ladder.

6 hours ago, pyro690 said:

Why not turn the buckets around so it scoops up instead of scooping down?

That's the easy solution, I have set out to replicate the way the real machine works and have achieved a workable solution, without need to modify the buckets I am using.

50 minutes ago, Saberwing40k said:

It already scoops up. The bottom of the chain arm is the digging side.

Thanks for the comment, will probably have to build a container so balls can be picked up by each bucket as it rotates around the end of the ladder.

It,s a challenging build that has a long way to go before finished, but that's what I like about Lego Technic.

Take a standard set build it and then modify it into something else.

My 1st. BWE became a bucket wheel trencher, and remaining parts used for GBC modules etc.

The 2nd set is providing parts for this BCE build.

Doug72

Edited April 30, 2017 by Doug72

[doug72]

BWE base now modified by installing two XL motors - PF receiver and a 8878 battery box.
Fitting the battery box proved the hardest so that it could be switched on / off by removing the 3 x 11panel. I would have preferred to have used a 8881 battery box but unable to install it without a major rebuild to base structure.

Each XL motor will drive one track via 20:1 reduction once I receive the new worm gears from Lego.
The XL motors now form part of the supporting structure.

The rotating upper part had to be modified so that the support for the 12T double bevel gear for slewing would clear the battery box, also had to remove the wedge wheel for the conveyor system.
Couldn’t see the purpose of it anyway - the rubber tyre wheel is still used to drive the conveyor positioning system.

Topside view.

 

Underside view

20:1 reduction gear boxes and PF receiver.

 

Access to battery box switch.

 

I will probably rebuild the rotating structure to simplify the drive for slewing using an M motor.

Will also modify the discharge conveyor using an M motor or link it to the bucket chain drive L motor depending on space.

 

Extra buckets now received and will use eight for now and if extend the bucket ladder I will add another two.
Eight buckets now fitted and tested OK.

Edited May 4, 2017 by Doug72
remove flicka file extenstions / added content

[jotta93]

It's coming along really nice 

Can't wait to see more of it

[doug72]

More Progress:-

Portal frame with hoist pulley support frame built.
Two M motors installed for slewing and hoisting - these will be controlled remotely.
Track drive also will be controlled remotely. 
Bucket ladder and discharge conveyor will be controlled manually by an interlock PF switch to prevent wrong way running.

General view:

Slewing:
M motor with 93.33:1 reduction giving a slow rotation.
The support for the drive gear which engages with the turntable ring gear had to be rebuilt to avoid contact with the battery box in the base unit as it passed over it.
Discovered that an 8L axle with stop if used protrudes below the 12T Double bevel gear just enough to hit the battery box - so a plain 8L axle was used instead.

Hoist for raising / lowering bucket ladder:
Side view of motor and worm drive gearing.

Top view showing rope drum and pulleys.

Next step is to build and install the discharge conveyor.

Edited May 5, 2017 by Doug72
remove flicka image text.

[doug72]

For the past few days have been trying out different positions for the discharge housing which had to be high enough to the buckets to pass without catching and still  allow balls to drop into a chute above the discharge conveyor.

Its a bit high and not ideal but the best I can achieve (at the moment) and still use the discharge conveyor as per the BWE design - which still to be built.
This will be kept as low as possible. Drive now installed for this conveyor using an M motor and a 8:1 reduction gearbox.

Eight buckets are now used but intend to extend the bucket ladder by an extra 5L x 7L frame and use a tensioning device to prevent chain slack and add two more buckets.

Present buckets are 7L wide but the build would have been easier if 5L wide ones were available.
(the BWE buckets are the wrong shape and too deep)

Bucket ladder hoist system works well and uses a 6 fold rope purchase.
The M motor with 8:1 worm drive has enough power to raise & lower the bucket ladder. 

All six motors now installed. 2 x XL, 1 x L, 3 x M.
A substantial counterweight will be required to balance the whole structure.
This will comprise of two large battery boxes and possible a lead weight.

 

Edited May 8, 2017 by Doug72

[1gor]

21 hours ago, Doug72 said:

For the past few days have been trying out different positions for the discharge housing which had to be high enough to the buckets to pass without catching and still  allow balls to drop into a chute above the discharge conveyor.

Its a bit high and not ideal but the best I can achieve (at the moment) and still use the discharge conveyor as per the BWE design - which still to be built.
This will be kept as low as possible. Drive now installed for this conveyor using an M motor and a 8:1 reduction gearbox.

Eight buckets are now used but intend to extend the bucket ladder by an extra 5L x 7L frame and use a tensioning device to prevent chain slack and add two more buckets.

Present buckets are 7L wide but the build would have been easier if 5L wide ones were available.
(the BWE buckets are the wrong shape and too deep)

Bucket ladder hoist system works well and uses a 6 fold rope purchase.
The M motor with 8:1 worm drive has enough power to raise & lower the bucket ladder. 

All six motors now installed. 2 x XL, 1 x L, 3 x M.
A substantial counterweight will be required to balance the whole structure.
This will comprise of two large battery boxes and possible a lead weight.

Doug this thing ended huge!!! And now you can say Gentleman start your engines 

[doug72]

9 minutes ago, I_Igor said:

Doug this thing ended huge!!! And now you can say Gentleman start your engines 

Its about the same size as the BWE but taller and will be awhile before everything works OK and I hook up the power cable.

Have now managed to compress & lower the discharge conveyor mechanism by 2L which will give more room to play with.
Just received from Lego the new worm gears which has helped solve a problem with the slewing unit which was fouling the 1/2 turntable which supports the discharge conveyor.

Next I hope to re-position & lower the discharge housing to get the bucket ladder closer to the ground where it pivots on the machine.

Clearances are tight for the buckets. Luckilly if they snag they detach themselves from the chain.

Have taken over our dining table as its the largest space on which to build it on and have parts to hand.

It has taken a lot of problem solving and back tracking as the build progresses !

[1gor]

5 minutes ago, Doug72 said:

Its about the same size as the BWE but taller and will be awhile before everything works OK and I hook up the power cable.

Have now managed to compress & lower the discharge conveyor mechanism by 2L which will give more room to play with.
Just received from Lego the new worm gears which has helped solve a problem with the slewing unit which was fouling the 1/2 turntable which supports the discharge conveyor.

Next I hope to re-position & lower the discharge housing to get the bucket ladder closer to the ground where it pivots on the machine.

Clearances are tight for the buckets. Luckilly if they snag they detach themselves from the chain.

Have taken over our dining table as its the largest space on which to build it on and have parts to hand.

It has taken a lot of problem solving and back tracking as the build progresses !

I told you in the past that I'll keep an eye on this project and must say great effort for this project. Usually big projects give big responsibilities and you shown that you are responsible with such level of perfection 

[Aventador2004]

@Doug72 great work, I don't know which I like better. Bwe vs bce showdown.