Search the Community
Showing results for tags 'escapement'.
Found 4 results
-
My mechanical clocks
Davidz90 posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
A compact, gravity powered clock. There are many Lego clocks around, but most of them are really huge contraptions, and for a good reason. They are easier to tune, more eficient, work longer... So naturally I took a challenge to make something small but still usefull :P. The key component is the pendulum. Typically, a significant length is needed to get period of one second. Here, a second mass over the pivot point slows the tiny pendulum down, so that it can be many times shorter than usual. The compact "knife edge" pendulum suspension dramatically reduces friction, decreasing the power necessary to run the piece. The low mass of components creates many problems. The clock is reasonably accurate (I got it within 5 seconds per hour), but tuning was a nightmare, and even a sneeze can alter its rate. The power source is 100g weight on a string. Due to only one hour working time, I have decided to use only minute hand. Seconds hand puts too much power demand on the mechanism. 1 by David_Z1, on Flickr 3 by David_Z1, on Flickr Schem2 by David_Z1, on Flickr Many thanks for KEvronista for inspiration to get into this Lego clockmaking hobby :) [EDIT]: embedded the video. -
[TC13] The Click Counter
schraubedrin posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
There is a mechanism i wanted to build in lego for some time and TC13 was the ideal motivation to do so. I don't dare to call it a clock, so it's a Click Counter, counting it's ticking Sounds by a set of hands Those are the specialities of this machine: The motor can be wound up without interrupting the workings of the mechanism. That's because input (wind-up-mechanism) and output ("counting"-mechanism) are connected like planetary gears. This way only torque gets transferred from in- to output, no rotations (the rotations go into the wind-up motor): Then comes the mechanism i tried to recreate: the constant-torque-converter. The main problem of wind-up-motor powered clocks is their inconsistency. The torque acting on the mechanism changes quite a lot over time, not a good property for a mechanism relying on good timing. This mechanism converts the energy from the spring into potential energy by gravity through lifting a weight up (weight block in the centre of the picture). By turning the lever only a few degrees from horizontal, the torque generated by the weight remains nearly constant. But there is a catch: a weight hurled upwards by a freshly wound up motor gains quite some speed and destructive power. To counter this, i built an aerodynamic dampener (left side of the picture). That's fancy for "fast-spinning fan". Not only does it control the movement, it also looks really cool in action Due to the nature of LEGO, there is a lot of friction. I could make the mechanism more reliable by lengthening the "sensor-lever" pushing on the Liftarm 3 x 3 L-Shape with Quarter Ellipse.(invisible on the right side of the picture) But in the end this whole mechanism burns a lot of energy while making the machine unreliable. Still, i love how it just "recharges" itself every now and then And finally, after some informative videos from @Davidz90 and a little bit of encouragement from @Didumos69, i managed to design a working escapement yesterday. Completely in System and geometrically locked (meaning the parts won't move over time). It's even surprisingly reliable. The clock face was put together tonight quick and dirty (like, admittedly, the whole machine). Using the 28 tooth turntable left me no choice but to give the hands a ratio of 1:7. In the end i'm happy to have found an integer solution. And finally, here's the video i spend far too many hours on, concerning the low quality of the result : At this point i don't even know whether i should enter the competition. As you can see the model is an unfinished mess and i doubt i could build it much nicer, especially not until tomorrow evening. Furthermore i made no pictures of my prototypes, so i don't even know whether this entry will be allowed. On the other hand, i think those mechanisms are really cool and interesting and worth a second look. What do you think? Would this be a worthy enough contender? -
A practical LEGO technic clock
dsharlet posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
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 :) -
[MOC] Fully automatic Clock
Gonkius posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
This is a fully automatic clock that was finished end of 2014. So, why do I call it "fully automatic"? - The clockwork runs as a normal mechanical clock with a pendulum and counterweight. - There is a motor that winds the clock every hour. - The speed of the clock is adjusted once a day using the Mindstorms unit. The speed is adjusted by changing the length of the pendulum. In total, the clock runs for itself without any assistance, and it shows the right time, even if it is build using only LEGO bricks. (Apart from the string to the counterweight) There have been many challenges in this design. My main focus, except the obvious goal to make everything to work, was to make this as compact as possible. The whole clockwork fits inside 14x14x14 studs. I did a short video to show the "action": The two sensors are used for: 1. Stop when the counterweight is fully winded 2. Give feedback from the minute hand rotation back to the Mindstorms unit. The counterweight is made out of 12 train/boat weights and is about 0.68kg. Winding is done through a differential to avoid interruptions during the winding. There are two medium motors inside the clockwork for the winding and adjustment. The Mindstorms unit is hidden in the base behind a hatch: WIP pictures Specially designed differential gear to reduce the friction between the counterweight and clockwork as much as possible. The winding motor rotates the large turntable gear: Clockwork prototype, without any automation: Very first prototype of the escapement: