Відео

It’s still running, but I’ve only made minor tweaks since this video. The escapement now has recoil shock absorbers, the freewheel is much more robust, and I redesigned the gear train between the escapement and the hands, but overall it looks very similar. I think this design is close to exactly what I want, so I don’t have a lot of motivation to change it much 🙂

​@@DillonSharlet Please give an update. I'm considering building it, but I'd like to have any improvements you've added since this video.

The key part of the mechanism is step 20 of the instructions dsharlet.com/file/grasshopper%20clock.pdf. I've since simplified the design to eliminate the differential, it's now just an axle with a linear clutch, a bit like this one ua-cam.com/video/--jds1Za6_I/v-deo.html, though I used the same friction peg from step 20 in my instructions

Balancing is important. It can be adjusted by either moving the yellow bushings on the escapement (tricky), or by tilting the entire clock (easy, if your mount allows it). BTW, tilting the entire clock is often how its done in "real" clocks (e.g. by putting shims under the feet of a grandfather clock). My weight is 560 grams, plus whatever the lego parts used to build the weight structure weigh. It might help to start with a bit of excess weight (or simply add some torque to one of the gears in the drivetrain with your fingers temporarily) to help get things tuned. It will definitely take some tweaking to get it running well!

There are instructions here: dsharlet.com/file/grasshopper%20clock.pdf

The instructions are for the version shown in ua-cam.com/video/To6Pg0Fo_8Q/v-deo.html, with an improved version of the escapement.

Nice! Once you get it working, hopefully you can fine tune and increase the gear ratio. 3:1 is another possibility between 5:1 and 1:1 (using the newer 36 and 12 tooth bevel gears).

@@DillonSharlet It worked for 7 hours until the weight reached the bottom (the consequence of the gearing) Then I tried starting it again and it just will not go. I think it was because I had to adjust the arm as my second was much too long in this video and I needed a shorter arm. Ugh. I want to try and get it to a single arm down as much as possible. And I'll redo the adjustment. Actually I may want a longer arm and maybe shoot for a 2 second period maybe 1.5 second and redo the gearing after. I think a longer arm would give more play at the escapement.

My pendulum started falling off without securing it more like this I am hoping I can find a good solution. thant doesn't introduce too many changes that would effect it from working. I just got the silicon oil to try.

Unfortunately I think my pendulum relies on the steel axles I used, which have a *very* tight fit in axle connectors... you could try jamming a thin piece of paper into the connectors along with the axles or something like that?

@@DillonSharlet I think I will try using liftarms for my pendulum. I'll need to figure out a way to move the escapement out just a little for more clearance and a longer axel for the escapement gear.

I got the pendulum length so that the center of the weight should be close to 1/4 meter so that the period should be 1 second. It never swings long enough that I can really judge how long it is taking. I have the weight as close to 560g as I could.

Seems like they escapment arms are stuck but they seem to move freely to me when I touch them.

I've also struggled with the escapement pallets sliding instead of rotating. If you've made sure those pallets spin as freely as possible, another likely cause of this is the escapement not having enough torque. You might try adding some weight, and making sure that the whole drive train spins as freely as possible. The other thing to check is to make sure the clock is balanced, so it clears both pallets similarly easily.

@@DillonSharlet Yeah I think I'll take it apart and look at the comments about recommended lubes others suggested on your video.

The weight on my clock is 560g (just the washers), plus whatever the various lego bits used to hold the weight are.

looks like maybe 1/4 meter according to omnicalculator physics simple-pendulum calculator for about 1s Period?

The pendulum should have a period of exactly 1s. I've had to experiment a fair amount with the length of the pendulum to get the clock to run accurately. The ideal pendulum (point mass) should be around 1/4 meter, but I'm not sure how close to ideal our pendulums are.

@@DillonSharlet They must get a little acceleration to keep them moving so yeah I think I got it.

Cool, I hope the build goes smoothly! Post a video of it if you can!

Sweet I figured out how to upload your io file to bricklink and had it come up with carts and it came to about the same amount. :-) I will certainly get a video of it. I'm only worried about how to adjust the escapement. I will post my attempts at it.

I had issues with the escapement gear binding with the clock face. I ditched the securing bars to it and used the blue 3L pins to hold it 1 brick further out; consequently I moved both hands out further as well. I used a 3x3 T shaped lift arm to hold the hour hand 2 more out as it was binding as well. and I used a 2L + 3L axel with connectors to hold the minute hand further out. I used a drill bit without a drill to make the pin that holds in the escapement arm slid in and out a bit better. The washers I found that fit the lift arm did not weigh as much per height so I needed to use two lift arms that I split the weights across. I'll try and mount it tonight and see if I can take a short video of it. Time to test my escapement adjustment skills. I plan on printing a paper clock face so my kids can learn to read it better. When I finish I'll have to take it apart a bit and put it in a box for Christmas.

@@jeffsadowski Sounds like you are close to getting it working :) Regarding the clock face and escapement wheel, this can be adjusted by rotating the pin + hole part holding the pin + ball joint for the bar. It seems like many of the other modifications stemmed from that?

@@DillonSharlet ua-cam.com/video/Mi8j4CH2770/v-deo.html

The loop is important though, it balances the weight on the drivetrain so the torque doesn't change as the chain passes from one side of the clock to the other :)

Mine is actually different from that one, mine really does have one fewer of the chain pieces. I think that design will not hold the axle straight enough and result in excess friction, because it's missing the 1L tube to hold the two axles in line. Mine is similar though!

That part is $0.01 each on bricklink :) But of course, you should make changes if you like. Another alternative is using a ratchet mechanism, that's what I did at first. I'm actually still trying to think of a better way to implement this, I don't like how much backlash there is in the hands currently. I'm thinking about using an inline clutch built directly into the minute handle axle. The tricky part is finding another way to implement a 1:2 gear ratio without more backlash than a differential...

@@DillonSharlet Yeah I know I can get parts for cheap but many stores on there don't let you get one hard to find item without a minimum purchase. I'm now thinking of an even better solution. I think the rubber bands would slip funny and stretch back and forth. Maybe a wheel with a rubber tire that I push up against something that I can adjust the torque.

@@DillonSharlet I just want something that is more repeatable. I'd think it is hard to adjust the torque on this. Sand too much and it spins too freely sand too little and it binds up.

So not sure if it helps, but I didn't sand the ridges, I cut them off with a knife. There are 8 ridges (4 on each part of the axle), I cut 6 of them off, leaving two on opposite sides. I think this is pretty repeatable.

Thanks for your comment, glad to hear you are building it :) 1. They are 13/32" ID, 2" OD. I would recommend just bringing a beam to the hardware store and getting the biggest washer with the tightest fit you can. The ones I use do scrape the beam a bit. 2. My pendulum rod is steel LEGO compatible axles I got from store.bricklink.com/eezo#/shop, which unfortunately appears to be shut down now. I think the pendulum length depends on drive torque and other factors, I've had to experiment a lot with the pendulum length, especially to make it so the pendulum bob screw adjustment is useful in both directions. The nice thing about those steel axles is they are a very tight fit, so the pendulum doesn't pull itself apart as easily. 3. The building instructions maybe will show you everything you need? dsharlet.com/file/grasshopper%20clock.pdf