I present my new build:

over1 by David_Z1, on Flickr

It is a 170 cm high grandfather clock, built with about 9000 bricks. The structure is meant to be bio-inspired, with a double helix (dna-like) pattern. The main load bearing element are four technic brick reinforced pillars at the edges, which are connected by the said helix-like grider structure. The power is provided by a pretty light (by my standards anyway :P) 0.3 kg weight. It is sufficient for 16 hours of operation.

mainw by David_Z1, on Flickr

The clock face is constructed mostly with 1x2 plates, the whole structure is under slight tension.

over2 by David_Z1, on Flickr

The hands assembly uses my new solution with worm gear. The minute hand (axle) is geared up 2:1 and then geared down 1:24 to differential casing, which holds hours hand.

hands by David_Z1, on Flickr

The escapement used here is a so-called Grasshopper escapement, invented by John Harrison. My particular implementation uses two wheels to make the whole mechanism completely symmetric. The system is highly efficient (needs 70 microwatts to run) and accurate (clock error is under 1 minute per day)

escapement by David_Z1, on Flickr

 

Video:

 

I've always been impressed by Lego clocks and this silent grasshopper mechanism is very smart !

Nice piece of of furniture !

Thanks! The lack of ticking sound is sometimes troublesome, my standard way of measuring accuracy is to record ticks and run the recording through computer program to get average periods, standard deviation etc. Here I had to use more rudimentary methods - sitting in front of the pendulum with a stopwatch. 

Very cool. I'm jealous of your patience to figure out the mechanism. Also, nice part use of the Windsurfer mast for the clock hand.

9 hours ago, Thirdwigg said:

Also, nice part use of the Windsurfer mast for the clock hand.

Thanks! Good thing they come in red color. At first, I used a black one but that turned out to be completely unreadable.

That's an amazing peice of work!  Perhaps you could consider making instructions, at least for the mechanism parts?

I really like the hands mechanism. Very clever. Can you set the time by rotating the minutes hand or is it not back drivable like that?

55 minutes ago, aeh5040 said:

That's an amazing peice of work!  Perhaps you could consider making instructions, at least for the mechanism parts?

Thanks! Yes, I plan to make instructions. Maybe even for the whole thing - tower build is quite repetitive.

31 minutes ago, lcvisser said:

I really like the hands mechanism. Very clever. Can you set the time by rotating the minutes hand or is it not back drivable like that?

Thanks! Yes, the mechanism is back drivable and time can be set by rotating the minute hand. In addition, each hand has its own slip clutch so they can be adjusted independently - quite handy for small adjustments of their relative position.

Edited February 12, 20232 yr by Davidz90

On 2/12/2023 at 12:11 PM, aeh5040 said:

Perhaps you could consider making instructions, at least for the mechanism parts?

I made full instructions for mechanism, tower and face :D

Link:

https://drive.google.com/file/d/1EwCfTyq6BigSetNr13E3AM7ZKMQYWOEe/view?usp=share_link

27 minutes ago, Davidz90 said:

I made full instructions for mechanism, tower and face :D

Link:

https://drive.google.com/file/d/1EwCfTyq6BigSetNr13E3AM7ZKMQYWOEe/view?usp=share_link

Cool! If I get back into clocks sometime I might have to try out your design.

40 minutes ago, Davidz90 said:

I made full instructions for mechanism, tower and face :D

Wonderful!  You might consider putting this on bricksafe (and possibly rebrickable).

Awesome, thanks. Simpler and fewer pages than I expected. The explanation of how the escapement works is also appreciated!

I might build the escapement, but I doubt if I’m going to build the tower. Too many bricks needed. Pretty sure the mrs. doesn’t approve ;-)

18 minutes ago, aeh5040 said:

Wonderful!  You might consider putting this on bricksafe (and possibly rebrickable).

Sure, I'll look into it tomorrow.

5 minutes ago, lcvisser said:

I might build the escapement, but I doubt if I’m going to build the tower. Too many bricks needed.

Understandable. Frankly, I wasn't sure if there is a point in including the tower instructions.

This is a fascinating mechanism, really nice build. I feel like I need to study the instructions (thanks for that) until I understand how it works, because I actually have a clock like this at home that I inherited from my grandfather. And it's still working :) Too bad this one is silent, as my favourite thing about the real one is the sound it makes; it's so relaxing for me.

Just out of curiosity, can you tell what the operation time depends on? How is it related to the weight / length of the pendulum? My real clock is about 1m tall and runs for 1 week with a reset.

14 minutes ago, gyenesvi said:

Just out of curiosity, can you tell what the operation time depends on? How is it related to the weight / length of the pendulum? My real clock is about 1m tall and runs for 1 week with a reset.

The operation time is directly related to the amount of energy the driving weight stores - how heavy it is and how far it goes down. It is only indirectly dependent on the pendulum - longer, slower pendulum loses less energy due to air resistance, so it needs a little less power. Real clocks are a good deal more efficient than Lego ones, but even with Lego a one week running time is not out of reach; this particular one would need a driving weight of approx. 3 kilograms to run for one week. My previous clock uses four 1.5 kg weights and runs for 10 days.

Overall, pendulum clocks are fantastically efficient machines - this one has a power of 70 microwatts  (0.00007 W). 

1 hour ago, aeh5040 said:

You might consider putting this on bricksafe

Done:

 https://bricksafe.com/pages/David_Ziemkiewicz/functional-grandfather-clock

Rebrickable requires a full brick inventory and.. I'm not doing that 

 

I've put the grandfather clock in its final place in the living room and recorded a short hyperlapse video: 1 hour of running in one minute. The speed is basically dead on (without seconds hand, I cannot tell the difference after 24 hours, and any longer measurement is subject to long-term factors such as thermal expansion of the pendulum). The video also highlights the drop rate - in the span of 1 hour, the main weight drops by approx. 9 cm and the counterweight goes up by 9 cm. With 145 cm of space, this results in 16 hours working time.