Wooden mechanical clock project - prototype 1
ฝัง
- เผยแพร่เมื่อ 13 พ.ค. 2017
- I'm currently working on a wooden mechanical clock made with my 40 Watt laser cutter. This mechanical clock is different than other clocks because of the use of Roberts mechanism. The use of this mechanism makes the pendulum move very slow because I can simulate any pendulum length by changing the dimensions of the mechanism. This setup has a simulated pendulum of 8 meters, in a very compact design. The hinges are made from 0.06mm stainless steel shims. These shims have no freeplay or energy loss. All this combined gives a very energy efficient pendulum. The pendulum will still be moving after 20 minutes without any adding of energy. As escapement mechanism, I make use of the gravity escapement. This escapement makes sure that any change in friction over time in the drive of the clock doesn't change the frequency of the pendulum. This is especially important when using wood.
This first prototype does work and ticks for about 20 minutes. However, as you may see, the escapement mechanism adds way too much energy to the pendulum. Making it hit the sides and causes it to move too fast. The pendulum ticks every 4 seconds, but it should be at least six. I made a mistake in dimensioning the escapement mechanism. My goal for the next prototype is to have a working gravity escapement and a pendulum that moves once every 10 seconds.
![Micro Mechanica | 3D Printing the smallest possible mechanical model [Experiment]](/img/n.gif)
Wonderful build. Very finely tuned
one of the coolest ive seen.. would buy
Well done! That Roberts mechanism pendulum is a neat idea for getting a slower period in a smaller space. I tried doing a double bob pendulum for my desk top clock but had to scrap it because its Q factor was too low.
That pendulum arrangement is very ingenious. It can go unstable if the top pivots are opened at an angle a little more than the angle of the central triangle. It is interesting that it is so slow because the effective suspension point of the mass moves just a little ahead of it and then lags a little behind it, while the reaction on the two lower pivot point change with the position of the mass, to accelerate it and then decelerate it. That top mass is moving at what may be considered a horizontal straight line or a curve that could be changed from a lightly hollow concave to a straight line to a lightly hilled convex trajectory. The brilliant arrangement in which I shall try and deduce its mathematical equation. I made one and loaded it with an additional mass on the lower shelf when it went unstable and thus brought it back to stability. Engineers see beauty and wonder and elegance in everything around them even if it silent and invisible. Congratulations for coming up with this combination of links and masses.
Thank you for your kind words. However, I did not come up with this mechanism. It is called Roberts mechanism. The thing I did was choosing it and to combine it with elastic hinges because my goal was a slow pendulum
Brilliant!
Very nice.
I really like this idea for the pendulum ,i will be watching for the completed clock. Maybe you can offer plans when it is finished.
Thanks! I'll consider offering the plans when I'm finished 😉
It's nice to see that you might yet finish this clock. I bookmarked this a long time ago and even completed an analysis to confirm you can get the Robert's mechanism to do that. The key here was the relatively long main links. (Just following the online descriptions of the Robert's mechanism might mislead a person.) I'll have to study more to see what its sensitivity to amplitude would be, i.e. like circular error in a conventional pendulum, though the gravity escapement should help with that.
Your escapement has me intrigued too. I notice the escape wheel is also lift the arm after the pendulum has taken it; is that the mistake you describe? I can guess addressing that and the big nail will help with the excess power problem. Can you get a stop into it like in Brian Law's, Arnfield's, or some of the other gravity escapements?
It's a cool clock! Good luck with it!
You're right, the escapewheel should lift the arm before the pendulum grabs it. I did a lot of testing with the pendulum and wanted to see it in action. I haven't done any calculations on the escape mechanism so I just built something that looked right. That's why it isn't working properly jet.
Goed gedaan Dennis! Mooie trage bewegingen!!Berust de oscillatie van de pendulum alleen op de flexibiliteit van de metalen plaatjes? of heb je het Roberts mechanisme een beetje uit proportie gehaald zodat de potentiele energie van metalen gewicht meedoet, dat deze dus geen rechte lijn maar een lichte curve maakt?
Bedankt! Het is Roberts mechanisme die het zwaartepunt van de slinger een curve laat volgen. De radius die ik hiermee simuleer is in deze opstelling 8 meter. Maar door onnauwkeurigheden in het productieproces komt dit niet helemaal overeen. Ook krijg je met Roberts mechanisme niet helemaal een circel, maar eerder een parabool. Mede door deze dingen beweegt de slinger naar mijn zin nog te snel. De bladveren hebben volgens mijn berekeningen heel weinig invloed op de slingertijd. Ze zijn zeer slap en het gewicht is in verhouding heel zwaar.
It's like a "glider" rocking chair.
Пане, Денисе,ви можете показати креслення цього механізму, дуже цікаво,я дякую вам за працю, хай щастить вам
Bonjour, and bravo! Am I alone to feel oppressed by slow ''tic tac'' ? ;0)
Very nice, do you have prototype 2 finished and running?
Unfortunately not. for the last one and an half years I'm working on a stainless steel robot design. Videos of that will probably show up in the next half year or so. After that I'll work on the next clock prototype. I've lots of ideas to make it even better 😃
@@DennisBouw excellent, thanks for the update
the pendulum is hitting a hard stop on one end of its swing. you can see it sort of bounce. Address this or it will rob energy from your spring and the clock will not keep time. Otherwise incredible design.
Any new progress on the clock?
Unfortunately not. After this upload, my wife and I moved twice and got a baby. So I've been busy haha. I'll finish this project somewhere in the future but it'll take a while. I'm currently working on a custom shoe cabinet with the laser cutter. I'll post a video on building that soon.
Dennis, would you mind sharing these templates?
I'll consider sharing the templates when the design is finished.
Цікаво,а де істочник енергії