Mock "Perpetual Motion" - GBC Mark 2 version (DONE)

[doug72]

Mark 2: Progress.



Learning from the Mark 1 version which had some problems with synchronising the whole system, the drive input from the L motor is now at the two arm ball lift and hard coupled to the bucket wheel vi a reduction gearing.
 The final bucket wheel drive is via two knob gears without any need for a steeper unit.

The L motor dives the 24/16T differential using a worm gear engaging with the 24T gear.
 Speed is adjusted using a PF speed controller.
Output from 24/16T differential drives the two arm ball lift directly and the bucket wheel via a 2 stage 4:1 reduction gear box.

Four revolutions of the two arm lift rotates bucket wheel one revolution in eight steps.

The other output from the differential is held stationary until the striker pins on the rotating arms engage with the knob gear. Then the two 24T gears mounted on friction pins start to slowly rotate and also rotate the knob gear until it release the rotating arms again back up to for full speed until the next cycle.

This gives a long enough dwell time for the ball transfers to take place at both gondoliers.

At each revolution of the ams there are two periods at full speed and two at slow speed.

Everything now much smoother in operation without any jerkiness.

Next stage build the two ball runs and the ball gondoliers.

 

Edited December 19, 2017 by Doug72
removed image file text. / added image

[doug72]

Mark 2:  Progress and new problems solved.

The new steeper unit is working very smoothly and transferring balls onto the top ball run OK.

The Bucket wheel however has proved awkward to align consistently so that balls drop into each bucket. This time the balls are loaded from the side.

The long drive shaft (22L) from the 4:1 reduction output on the steeper unit had two universal couplings plus two knob gears for right angle drive to the bucket wheel which resulted in a lot of torsion and gear backlash causing bucket wheel to intermittently get out of sync.

Replaced the drive shaft with an 22L axle built up using 11 x 2L axle connectors and 9 x 2L axles which is much stiffer and more resistant to torsion.

Both universal couplings eliminated and in order to keep drive parallel two 24T gears used and the right anlgle drive knob gears replaced by two 12T double bevel gears, result a big improvement in bucket positioning but gear backlash still a slight problem.

Solution: 

The axle at the outboard side of the bucket wheel was supported in its bearing using a tan frictionless axle/pin.
 This was replaced by a blue axle/pin with friction and this ensures the drive system is always under constant  tension resisting any torsion or gearing backlash.

Buckets now all pause for loading balls in same place.

Bottom ball run to build next.

Edited December 20, 2017 by Doug72

[Boulderer]

Forgive me if this has been asked already ... did you try using a chain to link the drive between the two elements?

[doug72]

3 minutes ago, Boulderer said:

Forgive me if this has been asked already ... did you try using a chain to link the drive between the two elements?

Had thoughts about a chain drive but I don’t have any except the old style large Lego links which use the old toothed gears and I would have to completely rebuild steeper unit to be able use a chain drive.

Think a chain drive would have same issues unless kept tight using a jockey wheel.

The new drive is working OK.

[Boulderer]

It would be a fairly long chain, that’s for sure.

[doug72]

Mark 2:  Now running OK with four balls in the circuit.

After initial Mark 2 re-build still had a few problems which now finally sorted out.
Main issue was getting balls to follow the circuit without falling off !!

Bucket wheel has a friction pin at the outer end to ensure gear train doesn’t have any backlash.

Top ball run rebuilt and a cage made to ensure balls drop onto the bucket wheel which now has two rings of curved gear quadrants.

Next lower ball run rebuilt to also ensure the balls load into gondoliers correctly.

Speed now increased and running smoothly.

See new video of  this in action.

 

 

Edited December 24, 2017 by Doug72

[chroma cube]

Hi Doug, interesting module!  Have you done any thought as to how you would integrate this into a GBC layout, input, output, etc?

[doug72]

6 hours ago, chroma cube said:

Hi Doug, interesting module!  Have you done any thought as to how you would integrate this into a GBC layout, input, output, etc?

Thanks for your comment, the biggest challange was getting the ball timings right.
Designed as a stand alone GBC module, don't think it would meet the speed criteria for intergrating into a GBC layout but some elements might scale up.
i.e the steeper unit and the 2 arm ball lift maybe using BWE buckets !! 

[RohanBeckett]

well done persevering with this one!  it's really got a nice movement to it!

love the long driveshaft... nice way to avoid the twisting of a 32L axle :)

[doug72]

51 minutes ago, RohanBeckett said:

well done persevering with this one!  it's really got a nice movement to it!

love the long driveshaft... nice way to avoid the twisting of a 32L axle :)

Thanks for the comments, there were several times when I almost gave up but it finally came together on Xmas Eve.

The long drive axle is 28L long and still had a slight tendency to twist - but by using a friction pin on the bucket wheel outboard axle bearing it keeps all the gear teeth in contact.

I was determined to get it working without the use of ball control load/unload gates.

Final step is to place a white board so only the ball circuit can be seen with a dummy drive cord as per the YouTube video.

There might be a Mark 3 version next year as I received a Mindstorms 31313 set as an Xmas gift.