A practical LEGO technic clock

[dsharlet]

I've built a few clocks with LEGO over a few years, but none of them have been practical to use. To be practical, it needs to run for at least 24 hours, and be really easy to rewind. Having to spend more than 10-20 seconds with a winding wheel is too much of a pain (and my last clock took way longer than that!).

The main difference between this clock and my other clocks is the drive weight is on a chain, and the chain can be simply pulled back through the clock to rewind it (driving a ratchet instead of the drivetrain), solving the ease of rewinding problem. Some other details:

• The escapement is a Galileo escapement with a 40 tooth wheel
• The hands can be moved forward by hand to set the time via a differential ratchet
• The drive weight is ~600g (11 boat weights x 53g, plus the parts to hold it together), the chain is a loop connected to the bottom of the weight to balance the drive weight
• The ratio between the chain and the escapement is 416:1 (40:24, 2:1 differential, 40:8 x 3)
• The weight falls 2.59cm/hour, so with 3 feet of drop, the clock will run for about 35 hours (it's currently mounted a little over 5 feet off the floor, so it could be given enough chain to run for about 60 hours).
• It should be accurate to within a minute per 24 hours, but it will take some time to dial in the position of the bob on the pendulum
• The single thing that helps the most with efficiency is a knife edge suspension for the pendulum, I learned this technique (and probably other techniques too) from https://www.youtube.com/user/KEvronista and https://www.youtube.com/user/BenVanDeWaal

Here's a video:

And here's a slow motion video of the escapement:

I hope you find it interesting! I wanted to share the chain drive technique because I haven't seen it before, and it really makes a LEGO clock a lot more fun and less of a pain in the butt than a string on a spool :)

 

Edited November 5, 2017 by dsharlet

[MattL600]

It is absolutely brilliant!