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THIS IS THE TEST SITE OF EUROBRICKS!

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Posted (edited)

There is a mechanism i wanted to build in lego for some time and TC13 was the ideal motivation to do so.

I don't dare to call it a clock, so it's a Click Counter, counting it's ticking Sounds by a set of hands :grin:

 

Those are the specialities of this machine:

The motor can be wound up without interrupting the workings of the mechanism. That's because input (wind-up-mechanism) and output ("counting"-mechanism) are connected like planetary gears. This way only torque gets transferred from in- to output, no rotations (the rotations go into the wind-up motor):

brlQ4SQl.jpg?1

Then comes the mechanism i tried to recreate: the constant-torque-converter. The main problem of wind-up-motor powered clocks is their inconsistency. The torque acting on the mechanism changes quite a lot over time, not a good property for a mechanism relying on good timing.

This mechanism converts the energy from the spring into potential energy by gravity through lifting a weight up (weight block in the centre of the picture). By turning the lever only a few degrees from horizontal, the torque generated by the weight remains nearly constant.

But there is a catch: a weight hurled upwards by a freshly wound up motor gains quite some speed and destructive power. To counter this, i built an aerodynamic dampener (left side of the picture). That's fancy for "fast-spinning fan". Not only does it control the movement, it also looks really cool in action :laugh:

Due to the nature of LEGO, there is a lot of friction. I could make the mechanism more reliable by lengthening the "sensor-lever" pushing on the Liftarm 3 x 3 L-Shape with Quarter Ellipse.(invisible on the right side of the picture) But in the end this whole mechanism burns a lot of energy while making the machine unreliable. Still, i love how it just "recharges" itself every now and then :blush:

O31bo1Hl.jpg?1

And finally, after some informative videos from @Davidz90 and a little bit of encouragement from @Didumos69, i managed to design a working escapement yesterday. Completely in System and geometrically locked (meaning the parts won't move over time). It's even surprisingly reliable.

The clock face was put together tonight quick and dirty (like, admittedly, the whole machine). Using the 28 tooth turntable left me no choice but to give the hands a ratio of 1:7. In the end i'm happy to have found an integer solution.

k7YqOIFl.jpg

And finally, here's the video i spend far too many hours on, concerning the low quality of the result :sceptic::

 

At this point i don't even know whether i should enter the competition.

As you can see the model is an unfinished mess and i doubt i could build it much nicer, especially not until tomorrow evening. Furthermore i made no pictures of my prototypes, so i don't even know whether this entry will be allowed.

On the other hand, i think those mechanisms are really cool and interesting and worth a second look.

 

What do you think? Would this be a worthy enough contender?

 

Edited by schraubedrin
Posted
2 hours ago, schraubedrin said:

invisible on the right side of the picture

I can see it...?

2 hours ago, Aventador2004 said:

It's awesome, but in my opinion, needs a little improvement without hoshpost everywhere.

If you rework the looks, definitely enter it!

+1

Posted

Wow, thank you for your kind words :classic:

I guess i'll rework the model today, luckily i don't have to work tomorrow, so i can pull an all-nighter :laugh:

 

4 hours ago, mocbuild101 said:
7 hours ago, schraubedrin said:

invisible on the right side of the picture

I can see it...?

It's visible in the video at the 28 second mark. I try to get better pictures for the second build.

 

I'm sad i couldn't implement my third idea: a rotational pendulum. It would look cool, has a nice long period and save a lot of trouble displaying the mechanism.
Unfortunately it introduces a crazy amount of friction and my escapement doesn't have nearly enough power to keep it moving.
Still, i wanted to show you my prototype:

5NDrypNl.jpg

Posted

Incredible! Looks a bit like a steam engine, especially the escapement part :sweet:. Soo many clever solutions here. I have never seen planetary windup mechanism like that and the constant torque converter is a very interesting design. In clockmaking, such mechanism is commonly called "remontoire". I was actually trying to incorporate one into my entry, with no success.

 

Great job! :thumbup:

 

 

Posted

I'm glad you decided to enter this excellent mechanical monster! I like the variety and interconnection of mechanisms in this, especially the aerodynamic damper. I don't think I've seen one in LEGO before; how effective is it at damping the weight?

Posted
2 hours ago, Davidz90 said:

such mechanism is commonly called "remontoire"

Nice to know the name.
I actually saw this mechanism at a museum, and was fascinated ever since.

2 hours ago, ColletArrow said:

how effective is it at damping the weight?

Very effective! Without it, the weight jumps out of its supporting beams.
Currently it's geared up about 1:80, so besides the aerodynamic resistance, there's quite a lot of rotational inertia. I mounted the fan blades on a friction pin to dampen the abrupt halt.

Posted

Ok, now that I'm home I got a chance to look at the video more closely. It's awesome. I though my "clock" was complicated, but this is a whole different level of complicated. And it works! You have my vote :thumbup:

Posted

Thanks to you guys i built a second version.

Now i'm editing a new video, hoping to be ready before Jim closes the entry topic :blush:

 

In the meantime, here's a comparison pic:
7NvqMi2l.jpg?1

And an uninterrupted video of it running:

 

Posted

here's my final entry with some more pictures. My main concern is the horrendous phone-cam quality :sceptic:

The Click Counter

A clockwork mechanism displaying the clicking sounds it generated by a set of two concentric arms.

Features:

  • Planetary motor mount for uninterrupted operation even during wind-up.
  • Torque equalizer: a mechanism converting the spring-energy of the wind-up-motor into a more steady gravity-induced torque.
  • Aerodynamic dampener: preventing damage through sudden bursts of movement by fan blades geared up 81:1.
  • Escapement build completely "in-system" and geometrically locked. No adjustments necessary.
  • Two concentric hands geared 1:7

Overview:
ZuCG8idl.jpg

Backside:
YB3FaBsl.jpg?1

And the not so important belly shot :wink::
tdwYgvAl.jpg?1

 

Again, i want to thank all of you for your support. I never expected such a positive feedback.

This really is a pleasant community :classic:

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