doug72

Stepper Unit Mk 4
 Now perfected a single motor stepper unit. Next stage is to connect to the 2 arm ball lift.

WD40 Is not a lubricant, it’s a water dispersant.

I agree - I tried freeze frame and OK for most of the video but at crucial moments bits cannot be seen, i.e, the trip mechanism to load trolley onto the lift and details of trolley gravity run section. That would be great, re auto reverse unit, it is more compact than a version I previously built for a GBC, so will have a go at building this idea as clear from video the construction. Its the lift section thats not clear how its constructed.

Thanks, will take a look the clock ideas. Happy at the moment with the two motor solution for bucket wheel. Changed the 2L stop pins for 2L pin/ ball, which work much better with the knob gear. Now working on the drive to the two arm ball lift and as I suspected this has added more resistance into the system and slowed the bucket wheel rotation so it does move onto the next step. More trials required for the differential friction system. Also due to gearing backlash in the drive from the BW, the two arm ball lift does not always stop at correct position. So it looks like I will have to build a stepper unit for it but syncronised somehow to the bucket wheel using an output from the M motor.

Stepper Unit Mk 3
 Having had many failed attempts to get a stepper unit to function consistently using only one motor and a differential I have concluded it not workable. So have now devised a two motor system to precisely step the bucket wheel (BW) which has an added bonus that the speed and step timings are adjustable for BW rotation & the dwell time for each step. No longer skips steps. The “L” motor still drives the BW via a differential but the other differential output goes to a gear train which has two 24T gears on friction pins, this allows L motor to run while BW is stationary. When BW is released the friction gears stop turning until the next step. The “M” motor drives via a 24:1 reduction a knob gear which holds & release the BW.
 No longer need cranks and lift arms to actuate the trip as knob gear slowly rotate 1/4 turn it release the BW and catch the next stop pin on BW rim. Now to start building the other part of this module. M motor and reduction gearing now placed within the main support frame legs

https://www.brickowl.com/catalog/lego-visor-2007-57702 also comes in transluscent blue

So am I, still trying to figure how to stop it happening. Think the bucket wheel has too much force and pushes the trip lever enough to allow it to skip if counterweight hasn't return lever to the hold position. Every time I add next stage the dynamics of the system changes !!! Might need a radical re-think with possibly two motors one to drive the bucket wheel the other to drive the trip system.

The Z60 turntable is very free running, suggest give it a try & test to see how much load it can take before rejecting them. The Balkirk Wheel MOC use six Z60 turntables and worked OK. If you are a Lego purists you don't have many other options ! Note: it is very hard to seperate the two halves of a Z60 turntable.

Steeper Unit Ver 2:
 Fine tuned the unit and added Yellow & red beams to highlight how it works. The red beam has two 12T gears on friction free pins and the 20T gear is on a friction pin. The 20T gear engages with the 24T gear on the output from the differential that drives the rotating arm that actuates the trip lever system via the yellow link beams. The retardation ensure that when bucket wheel (BW) is released it rotates as more drive goes the BW which has less resistance than the drive for the trip system. A counterweight ensure the trip system returns to stop position to hold the bucket wheel at the next step.

Finally got a reliable a stepper unit that stops the wheel precisely, without over shoot in 8 steps per revolution using a compact gear box to drive wheel & trip unit plus an output for the two arm ball lift, (yet to be buil). Achieved using a 24/16 differential driven by an L motor and worm gear on the differential 24T gear. Took quite some time to figure out the trip mechanism to stop the wheel and then release it but got there in the end. Better photos later plus a video.

Progress & problems ! Re-configured the stepper unit to also drive the two arm ball lift which required a 1:2 step up gear to synchronise the arm with bucket wheel. Steeper unit rotates and holds bucket wheel in 8 steps but occasionally overshoots which in turn effects the two arm ball lift position.
The only thing holding the bucket wheel stationary is the weighted arm acting on the knob gear.

Getting the two arm ball lift to consistently stop in correct position is also proving difficult due to backlash in gearing. Intend to try to make the steeper unit stop the bucket wheel by means stop pins on the rim of the bucket wheel with a knob gear preventing rotation until steeper unit turns knob gear 1/4t turn to allow stop pin on rim to pass. This means that drive to the wheel will have to slip while the wheel is stationary, using white 24t clutch gears or a linear clutch or would a differential work ? Possibly need another stepper unit for the two arm ball lift. Suggestions & ideas welcome.

You mean 180 parts are for one wheel, 19 wheels, Can,t imagine what you are building ?

Correct, I have a book with a whole chapter on perpetual motion with 50+ examples - NONE of which would work. Fairly happy with stepper unit, now working on a gear system to rotate the two arm ball lift to move time with wheel. The stepper unit acts like a Geneva Mechanism, the output from the 4 lobe knob gear is geared down 2:1 to give 8 steps of the bucket wheel. Once proven it works will "hide" the mechanism behind a white background board.

Friction is the problem and drive gearing. On my bucket wheel trencher which has the same gear frame set up, the gear ring with 8 buckets is rotated using only a single M motor only BUT via a 24:1 worm gear reduction engaging with the curved gear rack teeth for increased torque and runs very smoothly.

Difficult to understand what you are trying to build, can you post same images, preferably embedded photos not links. Doug

Wheel with 8 buckets now built plus drive system to rotate the wheel in 8 steps. Rotation is indexed using a 4 lobe knob gear. An L motor drives the rotating arm to advance the wheel to release each ball from a bucket and let it pause until next step. I have used white visors as buckets for one ball at a time but could use BWE buckets to increase number of balls carried.

Interupter gear now built and I have devised an 8 step Geneva Mechanism using a knob gear !!

Bucket wheel now built. I am building it as a stand alone module at the moment, but it could be put into a line if desired. The drive to bucket wheel will rotate it in 8 steps (number of buckets) using an interupter gear (currently WIP), the wheel in turn with rotate the two arm ball lift in sync. before discharging on to next module or return balls back to the bucket wheel.

Agree your comments completely. Will have a go at building something to replicate it, using the BWE curved gear racks and white visors for ball buckets Then devise a means of intemittently rotating the wheel in eight steps and connect the ball lift by gears and axles. With a white background to hide the drive system. Makes for a good challenging build which wont take up too much space.

Perpetual motion GBC ??? Found this on YouTube see video between 1m 26s and 2m10s Does this really work or is there a hidden input behind the white background ? Going to see if I can build a technic version but use glass marbles instead of GBC balls which probably too light to turn the big toothed wheel.

After re-tying all gear sizes found this is still the best solution using 20T double bevel gears: Support frame for gears made made stiffer using 4L x 1L angle beams & 3 x 3 Tee Beams Two versions: with a 60T turntable and without. If you need two gear rings connect them with beams and axles. To get rotation centre point two methods are used to centre turntable and and without T/T which can be seen in images.

https://www.brickowl.com/catalog/lego-technic-cross-block-2-x-2-split-axle-twin-pin-41678 You need four plus two 6L axles to connect to the turntable. I,ll add a photo tomorrow.

It’s used with an axle as a dummy hydraulic cylinder. I have some but prone to cracking around axle hole.

Yes that what I found. Note, the turntable as shown if 0.5 L off center,. It can be fixed by cross blocks 2 x 2 split (twin axle/pin).

I have tried to come up with supporting the rings inside using the shallow groove using 12T single bevel gears but none successful .

 This is the set up I used for my Bucket Wheel Trencher which provides good support and is very free running. Ample space to attach your rubber pads and still not obstruct the gears. Can be driven via any one of the gears. Note the uneven spacing of gears to get best teeth engagement without slackness.

 One pair has 9L spacing - the other pair has 11L spacing.
 The grey wedge wheels insure the gears stay on the gear.
 Centre turntable can be for support if required. Two gear rings possible by using longer axles to connect the 20T gears to get desired width. PS I ony have enough curved gear racks to make one ring at the moment as my TC12 entry used alot !