doug72

The “Beast” get bigger ! As I hoped the the AA battery box provides sufficient counterweight to the bucket wheel unit and the whole machine is nicely balanced on the tracks. IMG_3957 by Doug Ridgway, on Flickr IMG_3958 by Doug Ridgway, on Flickr PF Controls: The AA battery box has a stop so power can only be switched on in one direction. 3 x PF switches control the bucket wheel unit - to be house inside cabin section. Red lever:- Raise and lower bucket wheel. Yellow lever: Rotates bucket wheel with mechanical stop on PF switch to prevent wrong way rotation. Also supplies power to the conveyor PF switch so can only run when BW is rotating. Black lever: Powers the conveyor to discharge either side when digging. Tracks and steering use a PF receiver controlled using a remote basic controller. Track speed using an XL motor is quite slow, as are full size machines when digging. Steering using the subtractor unit has good control for wide radius turns and also on the spot turns. At the moment the 6 cylinder Vee engine is a dummy and not powered - maybe later. IMG_3959 by Doug Ridgway, on Flickr Next stage is to begin building the cabin and engine housings - not something I am very good at - probably need to order more 5 x 11L panels to complete this or raid the 42055 B model for blue 3 x 11 panels.

More progress and evolution: Unit tested and found hard to steer, with a basic controller turns only possible by stopping one track. With a speed controller able to slow one track down but still awkward to steer. Two XL motors a bit of an overkill so decided to build a subtractor unit. I built a longitudinal subtractor based on Sariel’s design shown on page 283 of his excellent "Unofficial Technic Builders Guide" book but using studless technic. The drive to track sprocket wheels is via two Lego worm drive gearboxes (the yellow parts as shown in at "C” in my post #12) They proved ideal as they lined up OK with the outputs from the subtractor. An XL motor provides the drive and the M motor provides the steering. Works OK with basic controller but much better with a speed controller to allow for wide radius turns. This unit will replace the two original XL motors and will be mounted so that both motors are at the front of the cab section. Along with a battery box this will help counterbalance the bucket wheel. Underside of track chassis:- IMG_3944 by Doug Ridgway, on Flickr Top view of subtractor drive unit:- IMG_3946 by Doug Ridgway, on Flickr Underside view of subtractor drive unit:- IMG_3947 by Doug Ridgway, on Flickr

That's why I will use two battery boxes, one for the two XL motors The other for wheel rotation / conveyor / raise & lower BW. (3 x M motors) Plus two batteries will act as a counterweight.

Progress to date: Tracked under carriage built and frame for L.A.s improved to give max digging depth and allow BW to be raised clear of the ground for travel when not digging. Each track is individually driven by a XL motor and a 24T/worm gearbox. Framing has to be well braced to prevent distortion. It took several re-builds until everthing was OK. Unlike the BWE there is no long arm to counter balance the BW. At present a lead weight is use to counter balance the Bucket wheel. Next step build cabin and engine housing, when I am hoping 1 or 2 AA battery box) will suffice as a counterweight instead of the lead weight. IMG_3942 by Doug Ridgway, on Flickr Overhead view. IMG_3943 by Doug Ridgway, on Flickr Its becoming quite a beast - at present its 58 Cm long x 22 Cm wide.

I've tried both: 2 x 24T gears to replace white clutch gears on the BWE - works OK but if anything jams you need to power off quickly. On the MOC of a Bucket Wheel Trencher I am using a PF "M" motor to drive the bucket wheel via a 24T / Worn drive. The Bucker Wheel rotates very smoothly at about 2.5 rpm without any jerking.

The tracked unit on the drawing would move towards the left with BW trailing behind with BW rotating clockwise as viewed. The support arm on the far right is what I called the "skid" - I think its purpose is to help support the weight of the BW and at same time smooth the bottom of the trench. See post #5 for an image of this shown for the 1175XHD BW machine. Still trying to replicate this arm without being too massive ! When MOC completed it will be almost at large as the 42055 BWE in size. Have had to modify my display shelves in order to store & show it.

Having proved that two L.A.s would raise and lower the bucket wheel OK I have modified the support frame for the L.A.’s and incorporated an L motor to drive them. Due to high loadings a strong worm drive gear box was required and this was built using 5L x 7L frames to prevent the gears jumping out of engagement. (I could have used the Efferman worm gear box but trying to build and be Lego legal) Both M motors for bucket wheel and conveyor have been re-loacated to lessen the load the LAs have to lift. Took a while to devise a drive path from these and required the BW support frame modifying to allow this whist still ensuring the support arm remained rigid without flexing. About 95% satisfied with the result - now only have to devise something to replicate the skid arm that trails behind the bucket wheel - see drawing. Next stage is to build the track unit to carry the BW. N.B. The red beams are temporary support while taking photos. Drive to discharge conveyor; IMG_3938 by Doug Ridgway, on Flickr Drive to bucket wheel:- IMG_3940 by Doug Ridgway, on Flickr Overhead view showing the two drive shafts: IMG_3939 by Doug Ridgway, on Flickr Drawing showing the “skid" device behind the bucket wheel: BWT by Doug Ridgway, on Flickr

Progress:- Decided to use M motors for the bucket wheel & conveyor but re-postioned closer to the pivot point. Bucket wheel and conveyor now completed, apart from the device that profiles the trench bottom. A test set up was used to find out if two Linear Actuators would be strong enough to raise & lower this unit and was found to be OK. Drive to the twin L.A,s is via a worm / 8T gearing using a PF-M motor which gives desired slow speed of movement. Tried 24T but too slow. Just have to play around with pivot locations to get right working and raised positions. Will probably use a L motor for the LAs as has more mounting options to help strengthen the frame when attached to the tracked chassis. Also needs more bracing to support & prevent the L.A frame ( 3 x 5L x 11L frames) from flexing. Bucket wheel in lowered working position: IMG_3935 by Doug Ridgway, on Flickr Bucket Wheel in raised position: IMG_3936 by Doug Ridgway, on Flickr Overhead view: IMG_3937 by Doug Ridgway, on Flickr

Several years ago I went to a family open day at the Vickers tank factory Newcastle Upon Tyne, England. Thay were demonstrating the British Army Titan Bridging system, which included the AVLB and bridge transport 8 X 8 all terrain vehicle which brings up the bridge sections. The whole procedure was shown from delivering the bridge section, unload onto the ground for tank to pick, deploy the bridge then drive both tank and deliver vehicle over. A very impresive display. See this link about British Army bridging equipment from WW1 to present day. http://www.thinkdefence.co.uk/2011/12/uk-military-bridging-equipment-assault-bridging/ Scroll down to see section about Titan bridging system. A combo MOC with both vehicles would be very impresive.

Should be possible to use the existing BWE gearbox as built to run:- Outputs:- 1/ BW rotating in cutting direction only. 2/ Dischage conveyor in either direction (on BWE rotates turret CW or ACW) 3/. Raise and lower Trencher wheel unit. (on BWE drives the tracks) On my MOC build the three motors for the Bucket wheel unit will be controlled by 3 interlocked PF switches, mounted in the cabin. The track drive will use one PF Receiver running two XL motors.

Fantastic and faithfull MOC of this bridge layer. Here are some images of this tank plus the earlier varient. Churchill Bridge layer tank - Post War. bridge layer-2 by Doug Ridgway, on Flickr Same type of bridge laid by Churchill Mark IV-ARVE tank in Oct 1944 using an earlier version that used an A frame shearleg with cable winches. bridge layer-1 by Doug Ridgway, on Flickr Earlier version mounted on a Petard - Mark IV Churchill tank bridge layer-3 by Doug Ridgway, on Flickrs some images taken

My MOC is quite ambitious with all functions powered by 5 PF motors. A simpler version might be possible using 42055 parts alone if use the BWE gearbox to power the bucket wheel, discharge conveyor, raising & lowering the wheel unit with caterpillar tracks un-powered.

B model frustration:- Got all the way to step 510 page 427 and tried to install the hopper conveyor unit only to discovered I had made an error somewhere as the last piece would not fit !!! Errors eventually traced to step 258 page 247 and step 279 page 262 where I had put the buff frictionless pins in the wrong hole, i.e. 1L too high. At least working from a computer screen you can zoom in to see better detail. Build now back on track.

More progress. Drive for discharge conveyor: Reversing will done by PF switch to allow discharge either side. IMG_3933 by Doug Ridgway, on Flickr Overhead view showing the layout of drive motors. IMG_3934 by Doug Ridgway, on Flickr Both M motors in position shown for testing only - later both will be moved further back on the support arm or onto the main chassis and connected via drive shafts and universal couplings. Discharge conveyor runs a bit fast and will be slowed down later when motors are repositioned. Support framing started but needs a lot more work - hopefully two Linear actuators will be able to raise and lower this unit, if not will try the new gear racks. Must finish the 42055 B model in order to release parts for this MOC.

Still building the 42055 B model and using parts that I know won't be used to start the BWT MOC. Don't think the BWT MOC can be built using 42055 parts alone. Will have at least five motors for operating :- Bucket wheel rotation Discharge conveyor Raising and lowering BW cutter head. Two motors for track drives possibly using a substractor system to allow for slow turns. Its a long term project, bit by bit. Doug

Worm gear box images:- Will be using the 2nd version shown. The bucket wheel rotation is very smooth and without any jerking. Next step is to devise the drive to the discharge conveyor using an M motor and PF switch. First Lego built worm drive gear box: rejected as being too flimsy. IMG_3929 by Doug Ridgway, on Flickr Second Lego built worm drive gear box: will used for MOC IMG_3930 by Doug Ridgway, on Flickr Selection of Worm drive gear boxes: A/. Efferman 3D printed, compatible with studless technic, very compact and usable with 8T & 24T gears. B/. Lego Gearbox for worm gear 32239 - for use with 24T gear only C/. Lego 2 x half worm gearbox. for use with 24T & 40T gears. B & C compatible with studded technic meaning thin spacers required when used with studless technic. C is rather odd, bulky and can't see any use for the gear teeth at one end. Attachment points are not very good. IMG_3931 by Doug Ridgway, on Flickr I have a cunning plan to demostrate the MOC once completed and hopefully picking up small Lego parts supplied with the BWE set.

Yes it's possible but not as compact. Have devised a gearbox using all Lego parts with the motor relocated to represent the hydraulic motor on the real machine. Will post an image tomorrow. Doug

I will be making a tracked version and posting updates at each stage of construction. I use the design & build as you go method - if it doesn't work try try something else until it does. The bucket wheel & discharge conveyor are the most complex part of the build hence building it first, once satisfied will then build the rest of the MOC around it. Once complete the 42055 B model it will release more parts for this MOC.

This is what I am basing a trencher model on - probably a freelance version. http://crosscountryi...013-Catalog.pdf The last one shows an unusual trencher that runs on heavy duty tires instead of tracks and has a straight bucket arm rather than a circular bucket wheel.

Close up images showing how the TBW is supported and driven: Support gears and drive to bucket wheel for top section - support arm yet to be built. N.B wheel is upside down. IMG_3928 by Doug Ridgway, on Flickr BW support gears for lower section that enters the trench: IMG_3927 by Doug Ridgway, on Flickr

Thanks for the feedback - now sorted after I managed to create an account with Pinterest.

Using the Bucket wheel from the 42055 set, I have developed at Bucket wheel for a Trenching machine I am currently building. It is directly driven by an M motor using an Efferman worm drive gearbox at approx 2.5 RPM using a 24T gear but could be increased to approx 7 RPM using an 8T gear. The BW is designed such that the lower part of the support framing and gears do not extend out side the width of the buckets. Next step is to construct the arm that will carry the bucket wheel and design a side discharging conveyor. The conveyor will pass through the grey 5 x 7L frame and will be driven by an M motor & gearbox to discharge either side using a PF change over switch to reverse direction as required. Side view of Trencher Bucket Wheel IMG_3924 by Doug Ridgway, on Flickr End view of TBW IMG_3925 by Doug Ridgway, on Flickr Overhead view of TBW showing drive motor and gearbox IMG_3926 by Doug Ridgway, on Flickr

It will be a while - currently building the B model but won't be using the buckets, keeping the bucket wheel intact and will use other panels to replace them on the B model as they are only cosmetic. This is what I am basing a trencher model on - probably a freelance version. http://crosscountryi...013-Catalog.pdf Includes drawings of the various trenchers this firm makes. I have some ideas for supporting and driving the BW and for the discharge conveyor.

Thanks for that just started building the B model.

Just finished dismantling the BWE in order to start the B model. Anyone found out what the single worm gear in the BWE was there for - seems to have no purpose other than acting as a 2L spacer.