[TC13] Pentagon Clock - Wind-up Pendulum Clock

[Didumos69]

48 minutes ago, schraubedrin said:

i want to build in system with geometrically locked parts.

That's my goal too, but that doesn't make it easier. I also want to have some level of symmetry. Most complicating factors are self-imposed rules . My current implementation is completely in-system.

[Didumos69]

Update. In the past week I spent hours and hours to get an escapement working with the 8T saw blade. It all comes so precise. I had many configuration working, but it all relied on finger-nail spacings and that's simply not my style. I want something that is easily reproducible and preferably in system. Eventually - after a last nightly building session - the trick was to deliberately introduce some slack in the stoppers by using frictionless pins. I now have two types of stoppers that both work, one with minifig hammers and one with pneumatic T-pieces. I prefer the pneumatic pieces, because the are locked-in, the hammers could slide out off position even though this didn't happen in my test runs. The whole setup does not require any fine-tuning, you can't build it wrong. You only need to make sure all gears run smoothly. This means I could make instructions for this build.

Now I'm in the process of fine-tuning the weight and length of the pendulum. The best run I've had sofar gave me 50 minutes autonomy.

Here are some WIP video's:

Edited January 27, 2018 by Didumos69

[Davidz90]

Awesome! I love the sound of this clock - the tick-tock is very symmetrical and steady, which is truly a great achievement, and done in system too! Just wow.  

[Didumos69]

On 1/27/2018 at 1:33 PM, Davidz90 said:

Awesome! I love the sound of this clock - the tick-tock is very symmetrical and steady, which is truly a great achievement, and done in system too! Just wow.  

Thanks! Here's a video of the escapement with saw blade:

There is one drawback to this implementation. The direction of the force pushing the pendulum to the left and to the right is not parallel to that movement. It works because the teeth of the saw blade slide along the stopper (pneumatic T-pieces), but this does cause friction. As a result the clock starts having a hard time when the pullback motors are about 50% unwound. This causes very different autonomy intervals. Once it ran for 50 minutes, but sometimes it stops at 30 minutes. When it stops early you can sometimes push it again and it will run for another 10 minutes. Not very consistent. My original escapement did incline force in the right direction and was much more reliable. It ran for 18 minutes every run and when it stopped the motors were about 90% unwound. And because reliability is more important to me than the length of the autonomy, I plan to revert to my original escapement this afternoon.

Edited January 29, 2018 by Didumos69

[Didumos69]

Pentagon Clock

This is a wind-up pendulum clock powered by two pullback motors. This clock is not true to real time but rather focuses on features such as a wind-up mechanism, pin wheel escapement and three concentric hands. It has been built completely in-system and can be reproduced without any fine-tuning, except for making all gears run smoothly of course (LXF-file here). The clock has a very consistent autonomy of 18 minutes. It features:

• A wind-up mechanism - A differential is used to prevent the hands from running counterclockwise when winding-up the clock. One of it's outputs is locked by default and slips during wind-up.
• Pin wheel escapement - Instead of using teeth, the escape wheel has three round pins that are stopped and released by a scissors-like anchor, which has been integrated in the pendulum.
• Three concentric hands - Planetary gears and a differential house make for a fictitious LEGO time system with 2 hours in a clock revolution, 5 minutes in an hour and 30 seconds in a minute. 

The pentagon-shaped clock face refers to the 5 minute hour. All features have been originally developed for this contest.

 

 

Edited January 31, 2018 by Didumos69

[schraubedrin]

This is really a piece of art. You should leave it like this on the wall

I was surprised how "empty" the housing is between the face and the wind-up mechanism. I guess i'm more used to my cluttered building style

[nico71]

This is very nice ! 

I follow the topic and see that you discover many thing about clock. In dead it is a looooong way to have a escapement which works fine with a good Q-factor, also not enought friction and of course small power consumption.

From my experience about clock, I recommand

• weight instead of spring / rubber band / pull back motor - > more constant in time (of coursed on this contect you have not the choice)
• pendulum of 1.5s, 40tooth as primary anchor gear (better autonomy : 1 tooth = 1.5s)
• galileo escapment, need some adjustement but very constant and power consuption

You can check the channel youtube on kevronista or mine for works about clock.

In any way, congrats for your work !

 

[schraubedrin]

3 hours ago, nico71 said:

From my experience about clock, I recommand

• weight instead of spring / rubber band / pull back motor - > more constant in time (of coursed on this contect you have not the choice)
• pendulum of 1.5s, 40tooth as primary anchor gear (better autonomy : 1 tooth = 1.5s)
• galileo escapment, need some adjustement but very constant and power consuption

Those are great tips.

[OT:]

Have you ever tried to make a clock with a remontoir?
Like i tried to do here (i hope its okay for me to post my own thread ):

 

Is the 40tooth gear so efficient because of the small angle its making between each tooth-jump? If so, have you tried making an escapement based on the new 60 tooth turntable?

[Didumos69]

11 hours ago, schraubedrin said:

This is really a piece of art. You should leave it like this on the wall

Thanks! I will certainly leave it hanging during voting .

11 hours ago, schraubedrin said:

I was surprised how "empty" the housing is between the face and the wind-up mechanism.

I wanted the escapement to be very visible.  One of the last things I did was swithing the bevel wheels with the 3 pins to the back side of the pendulum to make it even more visible.

3 hours ago, nico71 said:

This is very nice ! 

I follow the topic and see that you discover many thing about clock. In dead it is a looooong way to have a escapement which works fine with a good Q-factor, also not enought friction and of course small power consumption.

From my experience about clock, I recommand

• weight instead of spring / rubber band / pull back motor - > more constant in time (of coursed on this contect you have not the choice)
• pendulum of 1.5s, 40tooth as primary anchor gear (better autonomy : 1 tooth = 1.5s)
• galileo escapment, need some adjustement but very constant and power consuption

You can check the channel youtube on kevronista or mine for works about clock.

In any way, congrats for your work !

Thank you very much, sir! Yes, I have learned a lot and I've gained even more respect for others who have build clocks with LEGO. Your clocks are very nice examples by the way. Using 40t gear as primary anchor must be very efficient. However, I also wanted to make something original and I'm very happy I succeeded.

[nico71]

Yes 40t is one of the best because of angle between two tooth. With one rotation of the escapment wheel, you have 40x1.5s so good autonomy. But requires good adjustement of torque and friction (with a knife edge solution, the pendulum need a very low force to be keep moving).

On the escapement of this topic, with one rotation of the escapement wheel, you have only one period of autnomy but need less adjustement. But as you notice, the torque on the escapment wheel has a huge impact of the pendulum. That is why it has to keep moving, not accelerate this. Not easy ot do. But original.

Never do a remontoir but I assume it would be easy with motor. I prefer build a 24h clock with 2m string, this is a nice goal.

[Davidz90]

Lots of good advice sir! This contest was a lot of fun for me, and Your clock inspired me to try studless construction in the contest entry.

If I may add something, the Arnfield escapement is definitely worth a try. It is very power efficient - on my last big clock, 48h on 144 cm string (actually 72 cm with pulley). And most importantly, the pendulum is 100% separated from escapement wheel torque.

[nico71]

21 hours ago, Davidz90 said:

Lots of good advice sir! This contest was a lot of fun for me, and Your clock inspired me to try studless construction in the contest entry.

If I may add something, the Arnfield escapement is definitely worth a try. It is very power efficient - on my last big clock, 48h on 144 cm string (actually 72 cm with pulley). And most importantly, the pendulum is 100% separated from escapement wheel torque.

That is a really good thing. even on galileo, if not set correctly, can affect the pendulum. I will check stats. 72cm (with pulley) for 48h is defenitively a good autonomy, but with weight ? Mine at its best is 750gr / 140cm (no pulley, total lenght), 24h which is good for a start.

[Davidz90]

6 hours ago, nico71 said:

but with weight ?

2kg on a pulley, so 1kg per single support point. Here it is: