My mechanical clocks

[LegoTT]

17 hours ago, Davidz90 said:

Which one, exactly? 

This one,

https://drive.google.com/file/d/1F0I6FHT8jyRJfaDp8Td_nGbjcEde0Jnu/view?usp=sharing

which I believe be the same mechanism as this one

https://drive.google.com/file/d/1tbNfih7dY28Cv3CotBCrR4Pl8SmZic_Y/view?usp=sharing

I will only take the mechanism and the white rings idea as the full thing would be too big for his mother.

A smaller case made from identicals system brick from the lego shop wall should be a neat and cheap option, I will also order the other part new because mine are used a lot, and it show.

[Davidz90]

Yep, they are the same mechanism. The concern about size is understandable, my mom complains a lot about it XD

In terms of cost, weight on a string is considerably cheaper option than Lego chain. A smaller case is an option, in the most minimal version it can be a column of bricks, with pendulum hanging in front and weight at the back.

[LegoTT]

How would it perform with a 65t-long pendulum with only 5t or 6t of balancing range ?

[Davidz90]

2 hours ago, LegoTT said:

How would it perform with a 65t-long pendulum with only 5t or 6t of balancing range ?

Gear ratios will need to be altered to account for a shorter pendulum. For a one second period, the ideal length is about 25 cm (31 studs). For 1.5 second period, 56 cm (70 studs). For two seconds, 100 cm (125 studs). Escape wheel has 40 teeth, so it does 1 rotation per minute with 1.5 second pendulum.

The smaller, red one is designed with a short 1 second pendulum in mind.

[LegoTT]

From what I see on you modern style clock movies,

it's an about 165 stud long pendulum with an horizontal displacment of 30 stud.

So a 31 stud pendulum relate to less than 6 stud horizontal displacment, witch is in the good size to fit it IN a launch mount for a 4 stud-wide starship.

 

 

 

[Davidz90]

51 minutes ago, LegoTT said:

From what I see on you modern style clock movies,

it's an about 165 stud long pendulum with an horizontal displacment of 30 stud.

So a 31 stud pendulum relate to less than 6 stud horizontal displacment, witch is in the good size to fit it IN a launch mount for a 4 stud-wide starship.

Yes, this sounds about right. The amplitude is about 5 degrees, which equals to 2.7 studs displacement to left/right. Of course it's always a good idea to have some margin; building the mechanism, measuring the displacement and then designing the case accordingly is the safest option. Also keep in mind that weight distribution on the pendulum and driving torque affect the period somewhat, so actual proper length may be 32-33 studs.

[LegoTT]

Then if I get it right, from the small clock with the 31 studs pendulum,

if I want to use a 70 studs pendulum, I only need to remove the 16t/24t gears from the 40t gear on the below and put instead them two 20t gears isn't it ?

I will do the first order as soon you confirm it, the launch tower and starship are designed for about 40€, I will attempt to make the weight of the clock having a starship destacking cinematic.

Let me know if this sorta WIP is not relevant anymore for this tread and if you want me open a new one.

 

EDIT : I'm not sure about the step 26.

Is this acting with its adjusted weight or is it just a stop and I can switch the 4L axle for a 3L axle ?

 

Edited November 8, 2024 by LegoTT

[Davidz90]

10 minutes ago, LegoTT said:

if I want to use a 70 studs pendulum, I only need to remove the 16t/24t gears from the 40t gear on the below and put instead them two 20t gears isn't it ?

I will do the first order as soon you confirm it, the launch tower and starship are designed for about 40€, I will attempt to make the weight of the clock having a starship destacking cinematic.

Let me know if this sorta WIP is not relevant anymore for this tread and if you want me open a new one.

No problem, You can post in this thread. At first I was confused about starship, but it seems like a very cool project!

I'll write down the gear ratios in the larger (black/white) and smaller clock:

1. Black/white clock

Pendulum has a period of 2 seconds (125 stud length).

 40t gear make one rotation in 80 seconds

Front has 16:12 gear ratio to make it 60 for seconds hand

On the back, 16:24 makes it 120 seconds (2 minutes), then 8:40 makes it 10 minutes, then 8:24 makes it 30. Final 12:24 makes it 60.

 

with 70 studs (1.5 second) pendulum, 40t gears make one rotation per minute so the front dial needs to be 20:20.

on the back, 16:24 could be changed to 12:24 to get two minutes, but it needs a different gear spacing. Direct replacement with 20:20 will leave us with one minute, so extra 1:2 reduction has to be added somewhere. There's space for it (for example, in the place of the three 16t gears). Mind the rotation direction.

 

2. Red clock

This one uses one second (31 stud) pendulum and both in front and on the back, there is 16:24 gear ratio to change 40 seconds to 60. Here, exactly as you said, it can be replaced by 20:20 for 1.5 second (70 stud) pendulum.

 

[LegoTT]

A day to design the majority of the stand and a studless clone of the clock (for visual coherence)

without the extra gears that make the stock version versatile to use multiple pendulum lenght, I don't need this feature

and using this removing to make it more symetrical in an attempt to get a 30 hour working with a 15 times heavier weight and within a 11x15 stuless frame (3 more 40t gear to get x40 instead x3 right after the weight)

 

a loooong wait to get all the needed pieces and then a long wait to have some time to work on it

 

(I guess my newphen will have a nice picture of the WIP for his birthday, his mother will already ger him the curiosity rover it will be too much at the same time he is young let's see how he can build it)

 

Obviously it doesn't work, I just putted your stock clock on my stand with temporary enhanced rigidity with the recommanded weights to understand the key things and it's soooooooo beautiful to see it working, thank you for that.

 

Oh, now I wrote this it doesn't move anymore, get I have some work ahead !

Edited November 24, 2024 by LegoTT

[Davidz90]

I'm proud to present: A time table!

Terrible puns aside, this is a table that tells time. Takes less space than full grandfather clock and is useful as a table (as long as nothing extremely heavy is put on it).

 

[2GodBDGlory]

That's a pretty fun idea!

[aeh5040]

That's beautiful!

[Davidz90]

2 hours ago, 2GodBDGlory said:

That's a pretty fun idea!

1 hour ago, aeh5040 said:

That's beautiful!

Thanks! I have tested multiple ways to power this before settling on four weights, getting a good running time out of something this short was a challenge. Auto-rewinders tend to be noisy and I want to actually use this everyday, so heavy weights were the only option. I'm considering replacing the current weights with some sort of a single, ring-shaped one runing along the central leg for a cleaner look. There was also an option of making the leg thicker and hiding the weight inside, but for that I'd need something with really high density like lead or tungsten.

[Davidz90]

A little hybrid between a pendulum and balance wheel. Basically, the vertical part acts as a pendulum and the wheel adds inertia to slow it down. The result is a very compact, if inefficient, mechanism.

 

[JoKo]

On 3/7/2025 at 3:51 PM, Davidz90 said:

I'm proud to present: A time table!

Terrible puns aside, this is a table that tells time. Takes less space than full grandfather clock and is useful as a table (as long as nothing extremely heavy is put on it).

This is really nice! The idea is great and well executed. 

[Davidz90]

1 hour ago, JoKo said:

This is really nice! The idea is great and well executed. 

Thanks!

[Davidz90]

Some time ago, I came up with an idea to  encode numbers 1-12 in a compact manner:

With this "crown wheel" I could realize a striking mechanism with a counting mechanism that is rigidly connected to hours hand and cannot get desynchronized, unlike chain-based solutions. Normally, this is called "rack and snail mechanism" but a sufficiently precise snail cam seems to be almost impossible to build.

So here's the thing:

There is a gear rack that gets dropped on the crown wheel shortly before full hour. Then, at full hour, mechanism is activated and lifts the gear rack one tooth at a time until it reaches predetermined upper position and stops the mechanism. How many rotations (=bell strikes) will that take, depends on the position of the crown wheel (and so, hours hand).