TechnicBrickPower

Hi Bluehose Yes good feedback. I expected someone would raise those points. 1) You are right it is a cvt but when there is enough load all the power does go through the 1:3 ratio (I have seen the 1:1 path stop in practice), but in between it travels through both paths and the ratio is anywhere between 1 and 1/3 - hard to tell what the exact relationship is between the load is and the ratio. Good point about just using one 1/9 so maybe just one pair of diffs is enough - I thought I had a moment of inspiration when I put two in series. Point 2) In practice I haven't seen that happen. The blue pin (or the linear actuators) add a constant amount of load "c" to the output (for a constant speed) so the overall load is L = c + O ( O = load on output axle). Of course if L is large enough the whole thing stops (like any gearbox) and in fact there is no power transfer at all as nothing is moving so it can't be going into the pins at that point. If the load O is just below the this threshold then I am not sure what % of the work is lost in the blue pins vs the gear friction. An open question lol! Thanks! Thanks @TeamThrify & @Bluehose. All points raised are good ones. Thanks for your support - much appreciated.

Here's my 3 speed automatic gearbox MOC. The gearbox automatically switches between one of 3 gear ratios, namely a ratio of 1, 1/3rd and 1/9th depending on the load on the output. It uses two 2 speed automatic transmissions in series to create the three speed automatic gearbox. It works on the principle of 2 degrees of freedom within a pair of differentials. This creates two gear paths for the transmission of force and the path of least resistance is taken. The loading points at which this lego gearbox switches gears is adjustable via two linear actuators at the bottom of the gearbox, which adjust the amount of artificially introduced friction to control the switch over points. Hope you like it.

Hi @SNIPE ok I see I was imaging a logical OR gate used in computers. This is pretty cool - so if the input turn clockwise it selects one output and otherwise the other. That's clever. But is has a friction problem right? Still not sure how this well help with your problem as you are in effect selecting one of two different outputs instead of combining inputs which is what your gearbox idea seems to require. Instead of the OR gate design you have shown can't you just use two of the helicopters ones, i.e. two ratchets, one for clockwise rotation and the other for anti-clockwise. That way you don't need the gray friction pin to do the selecting.

Hi @SNIPE can you point me to where I can see an example of a lego OR gate. The helicopter video looked more like a one directional gate to me.

Thanks 1963 Maniac! I have my own url now too which is easier to remember.. http://www.youtube.com/technicbrickpower Hi Vascolp. I am not sure to be honest - I have never measured the friction of a gearbox but that will be worthwhile doing. I don't think the friction will be a lot less as the central axes of the driving ring is still rotating and held in place by a liftarm hole. LOL well trying to create some useful gearboxes for a change ;)

Hi @SNIPE, The fundamental problem with that approach is that you need to able to somehow change the gearing ratio at the output when you disengage a gear with the clutch gear, e.g. if the 2 clutch gears are in position [left, left] and then you change to [left, neutral] then somehow the shift from left -> neutral has to change gear ratio at the output - you're essentially disconnecting the gears from one another and not connecting to another. It's counter intuitive for that to work. However that said I have thought of a solution that I think would work but it's not going to be efficient or pretty.

Hi Snipe, thanks for calling me to help. Will do my best. Can explain more what you are trying to do? Just so I understand you said there are 8 possible combinations for two clutch rings, so you mean there are 3 for each (left, neutral, right) and since there are two of them that gives 9 combinations, but you are discounting the combination (neutral, neutral) to leave 8? Is that right? And therefore you are saying it should be possible to create an 8 speed gearbox based on that idea. I am on the right track..?

Here I present my 12 speed gearbox design. The gearbox implements 3 reverse speeds, a stop gear (zero speed), and 8 forward speeds. The forward speeds range from 0.307 to 1.2 and reverse from -0.067 to -0.36. The gearbox has a single gear lever to drive two rotary selectors to select the gears. Let me know if you like it, have any comments or questions.

Hi All, The instructions for my recent 4 speed rotary gearbox have been created thanks to 1963Maniac. They are on rebrickable https://rebrickable.com/mocs/MOC-45647/TechnicBrickPower/4-speed-gearbox Here's the youtube video explaining how it works. Hope you find it useful.

Thanks for your replies everybody. Great way to see old ideas dug up and presented again. I like the differential going through the turn table. That's a neat idea. That's a very impressive build, especially the idea of creating pentagons.

Hi Everyone, I have created this 4 speed gearbox based on the "change over rotary catch" component and I have used it to select 1 of 4 gearing inputs in possibly a new way by connecting to four clutch gears which then connect to a differential housing used as a method to transfer motion whilst allowing the rotary catch to be rotated freely inside of it. The gearbox implements 3 forward speeds, and 1 reverse. I was wondering if anyone has seen this technique before (I am guessing yes since most ideas are not new)? Anyway thanks in advance.

Ok awesome what are you thinking of attaching?

Thanks Paul - just checked out your blog - i like your idea of a modular truck base that allows the attachment of different functions.

Hi this MOC I did uses one as kind of a spring tension to push up an unlocking mechanism for a timer gadget. The advantage of a pullback motor used in this way allows you to adjust the tension by winding the motor up more or less.

Here I present a 871 part MOC countdown timer mechanism. The mechanism can be set to count down from up to 255 values implemented by a binary counter. Each count takes approximately 2 seconds giving a range of just over 500 seconds or almost 9 minutes. Once the counter has counted down it stops automatically and switches itself off.

Here I demonstrate a coin dozer cascade machine using lego pieces instead of coins. The machine is built from over 1,400 parts and weighs 1.527kg. It uses a crankshaft driven by a large motor to move the cascade sliders. Lucky punters can win some extra Lego pieces by dropping some of their own into the top of the device. Operator profits are made from two gaps at the front where pieces can fall into the hidden profit draw.

Hi Everyone, Here are the instructions on Rebrickable for the modular binary counter MOC I made a while ago. https://rebrickable.com/mocs/MOC-43585/TechnicBrickPower/modular-binary-counter/ Thanks to 1963Maniac for creating the instructions - great work as always and much appreciated. This is the youtube video showing how the model works:

Thanks aeh5040. I am sure you're not insane until you build a 1,000,000 speed gearbox. It is surprisingly robust. I have a had a few designs that looked good on paper but were dreadful in practice. Has helped me learn though. I will try loading it - I am tempted to turn it into some sort of vehicle just for a laugh.

Hi yeah it was a lot more complicated to build than I first thought, and yes probably not a great car gearbox - you wouldn't need 99% of the gears lol. But it might have other applications somewhere else.... Hi Rudivdk. I am not sure if it has applications but sometimes the invention comes before the application! For me it's more about the learning process and then if I do have an application that needs certain types of gearing then I might be able to create it based on this experience. It is well built yes and no lubricant other than my greasy fingers lol. I was surprised how well it worked, but then I knew if I kept the gearing ratio low (<=1) then it should be ok. Part of the trick is to make sure none of the gears spin faster than the input axle. I might try to put some load on it to see what happens - I think then the friction will set in quickly. Might turn it into a car lol.

Here I present an MOC gearbox with 1,000 different speeds. The gearing ratios are selected using 10 switching levers each of which adds a power of 2 to the overall output gearing ratio. A down gearing of 1000 to 1024 at the end of the gearbox means any 3 digit decimal gearing ratio can be selected, for example 0.123, 0.777 or 0.017. The gearbox uses over 130 gears and 12 differentials.

On rebrickable. Thanks to 1963Maniac for creating these instructions - a lot of hard work much appreciated. https://rebrickable.com/mocs/MOC-42806/TechnicBrickPower/billion-to-one-gearing-tower The video about it:

Hi JopieK. So you're a teacher then? Yes it's a neat build and the fact that's it's made from lego would make it more interesting for kids & adults! Are you interested in the build instructions?

A MOC modular binary counter is presented and used to measure the RPM of a large Technic motor. The counter is constructed of a series of 4 sides reels each representing 2 bits. These are held at neat 90 degree angle multiples by a micro stepper mechanism. The overflow bits are carried to the next reel using a 4 knob wheel pushed by a small lever arm from the previous reel. The design is modular such that multiple modules can be combined to create a larger counter. The counter demonstrated is made from 3 modules and can count from 0 to 4095 in binary. Enjoy!

Hi Everybody. Here are the instructions for the Word Combination Lock Safe MOC that I did a while ago. It's a fun and interesting build. Thanks to 1963Maniac for creating the instructions - much appreciated as always. https://rebrickable.com/mocs/MOC-41956/TechnicBrickPower/word-combination-lock-safe

Hi pleegwat. I was thinking about your idea - you could have the plate hit a limit switch which reverses the mechanism and it plays the sequence in reverse. If you have this at both ends you can have the plate "loop" back and forth.