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 !!!

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.

To strengthen CV's use small rubber "O" ring over the axle bush section or the method shown in Sariels guide book. 2L diam plate with 4 studs.

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

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

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.

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

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.

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.

I looking at two chains using the large Lego Links spaced at 6L apart. I only have enough spare to test various connections for the buckets (scoops). Connection to the chain requires two pin holes to ensure a secure grip on the track link studs linking them together and mount the buckets. Only have 14T chain wheels at present so need to source bigger ones plus lots more links. Re buckets - looking at what other Lego make i.e Duplo etc. to see if would connect, otherwise it will need 3D printing !! IMG_4486 by Doug Ridgway, on Flickr

Thanks Gabi Found that first you tube video last night and was going to post it this morning. have a clearer understanding now on how they work. Just tried to embed that video but can't seem to do it. I may have to try and find a chain excavator that rotates the other way like floating dredgers do. Tommy - thanks for your suggestions - I will look into them but probably a too costly build. I will try using the thin quadrant parts if they can accommodate Lego Balls. I used them on my Bucket Wheel Lift for the second stage transfer.

This would seem to confirm John's observation. I shall probably base my MOC on this machine.

Thanks for that observation. It's going to be hard to replicate that using the lego buckets that are available, will have to put my thinking cap on. The underside of the bucket arm must be flush until reaching the top drive wheel. That might explain the tunnel ike structure at the inner end of the bucket arm. Water borne bucket dredgers have the rotation the other way round with contents tipping out of the buckets as they go around the top drive wheel. Will have to do some more research !! Doug

It will definitly mounted on caterpillar tracks, using the 42055 design but with self contained motors etc. Still to determine which way the bucket chain should rotate as it cuts. Most seem to cut on the up slope but how does a bucket then discharge when it reaches the top chain wheel. If its the other way then then as bucket passes around the top chain wheel contents will drop out. Intention is to either use the small parts as used for BWE or lego balls. Found this image of a modern smaller BCE which cuts on the up slope.

I will use the bucket connection shown 2nd from left in Agrof post. Works OK without the other parts, very slight movement of the bucket but will help to align it with the guide rails. The end sections of the grey half 5L beam will run along guide rails on the bucket chain arm underside so that the chain doesn't sag too much. Hoping to use 16 buckets. At the moment I am building the 42055 BWE base with the tracks but will install two XL motors plus battery box and a PF receiver. Then build turntable top and gradually sort out the bucket chain arm structure.

Have thought about that solution but not yet tried it. Might be possible for the 5L lift arms to slide along side rails and use a large Lego chain the move the buckets with it located in between the lift arms. Now that I have a second 42055 set I can have the possibility of using 16 buckets, if I rob my BW trencher or buy some more !

Thanks - yes I,ve used them before for linking parts to tracks - they can be quite hard to pull apart. Its a very early stage for this project - just getting ideas put together before start building. Doug

This work OK with 5L wide track. The grey 5L - 1/2 beam is required so that the blue axle pins can grip the track tightly. Works OK with both BWE buckets and Clamshell buckets.

You could use two parallel large Lego chains and cross connect them by 5L or 7L beams and attach buckets to the each cross beam. Then as chain reaches top drive wheel and buckets descend again then whatevers in the bucket would drop through between the two chains. Would need a lot of extra links to do that ! I have plenty of the old 14T gears that mesh with the large chain links.

Thanks for the link to images - will study. Re Chain / Buckets: will porobably use the white visors as buckets as the BWE buckets are rather large and only have eight available They will be attached to the large Lego chain links as per my other MOCs. Now have obtained more chain links. The BWE 42055 will provide all the other parts that I will need and replenish my spare parts stock. Its a long term project.

Now that I have received another 42055 BWE set I am planning to build a bucket chain excavator as used for canal building similar to this early version and use it as a GBC:- Some images show buckets cutting up the slope others show cuts down the slope. Cutting down the slope buckets discharge is simple as they pass over the top drive wheel but if the buckets cut up the slope how do they discharge ? Does anyone have any information about this ? Thanks for any help in advance. Doug

Update: Found using 1:2 step up gears to get 180 deg. steps has too much backlash in the gears and rotating arm fails to align correctly. Changed the "Star" wheel to 4 arms and improved the indexing arrangement made. The index mechanism aligns the arms rotating wheel at 180 & 360 degs So for each revoltion there are four stops - intention is to load / unload balls at 180 & 360 degs. An alternative is to have only two arms at 90 degs. to each other to align for ball transfers but this gives a long dwell time for the other 270 degs of rotation. It took a lot of trial & error to get the "star" wheel, rollers and indexing system to work well. The 16L tie rod is required to stop the shock absorber pusing everything apart ! Short video:

I have built a test rig to demostrate the intermittent rotation when applied to one side of a Ballkirk wheel (note turntables are not interconnected). Biggest challenge was getting the index wheel and compression of the shock absorber correct. An XL motor gives enough power to rotate the wheel and overcome the index wheel giving 4 stops per revolution at 90, 180, 270 & 360 degs. To get 180 deg steps would require a 1:2 step up between star wheel and ball lift wheel. Video showing the action:-

Agree with all the comments above - it's definitly not a one day build - best done in stages, especially the B model. I hope to receive in a couple of days a second BWE set for my upcoming LXX birthday, which I will use as a very useful parts source for other builds and also to buld the PV Productions GBC 15 if I can find space to build it !! This is the first time I will have got two identical sets. At the moment in the UK most retailers selling at 25% discount or better.

42055 B model ! I gave up after two attempts.