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Hello fellows,

Let me present my idea for a stepper mechanism for sequential gearboxes (4 speeder). Please forgive me giving such a a short description, but I wanted to share this idea before I take of to my hollyday. I didn't even packed yet and I depart tomorrow :wacko: So I'll insert the video and copy its description here. I'm going to try to get online every day and react on questons and comments. Finally let me say a big thank you for Didumos69 and his 90 degree limiter for the inspiration.

This video meant to demonstrate the stepper, not the gearbox. The nature of this design allows it to be used with almost any kind of gearboxes.

I'll make instructions for the gearbox later however I've been trying to show it from every angle in the video so you can attempt to reverse engineer it. It isn't that complicated.

Stepper:

I've got the inspiration from an other idea what Diederik van Leeuwen came up with. He goes by the name of Didumos69 on the Eurobricks forum. Click on the link below to see his post:

http://www.eurobrick.../forum/index...

The reliability of this stepper depends on the right rubber rings. For the limiter I was using the small lego silicone ring and for the stepper (the green ring) a non lego one that is much weaker than the white.

If it is too strong it pulls the knobwheel back instead of sliding trough on it when it returns to the basic position. So find the right combination by experimenting.

It requires the frictionless driving rings in the gearbox.

The motorisation can be solved by using PF medium motor combined with return to center mechanism too.

Sorry for the lack of quality, it was a hasty work. I hope the point I was gonna make gone trough. If there is any question, please use the comment section. I'll try to answer it as quick as I can.

Thanks for watching an reading. Hope you find it usefull. :classic:

There is a few failed changes in the video, those wre caused by applying shorter route on the handle. This design requires to be turned to the end point (about 65 degrees).

UPDATE

Gearbox instruction video is uploaded:

Edited by Attika

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I)t looks very good, maybe you should consider to put the axle with the paddles 1 stud higher (at the same size of the clutches), so the engaging would be more accurate, but it is still a very nice creation.

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If you basically want a paddle-shifter, I've found that making a large (5-stud diameter) "+" shaped part out of 1/2-stud beams works better than using knob gears or a 2x2 System brick. I built a very reliable system on my Porsche 914.5 SpyTarg (200 shifts each way and no jamming, missed shifts or double-shifts), but it isn't the smallest.

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I'm not seeing a video, can you check it?

Sorry, I don't know why did the vid disapear... I've linked it again

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Thanks for the credits, I feel honoured :sweet:. Nice to see another use case of the 90 degree limiter.

I like your stepper idea. It reminds me of something similar posted by piterx a few month ago. His solution could also be combined with the 90 degree limiter:

I'm wondering whether it would be possible to use a 3L lever instead of a 5L lever in your stepper. Did you experiment with that? And maybe the LEGO red silicon band could replace the green one.

Anyway, thanks for sharing and have a nice holiday!

Edited by Didumos69

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Thanks for the credits, I feel honoured :sweet:. Nice to see another use case of the 90 degree limiter.

I'm wondering whether it would be possible to use a 3L lever instead of a 5L lever in your stepper. Did you experiment with that? And maybe the LEGO red silicon band could replace the green one.

Anyway, thanks for sharing and have a nice holiday!

crediting you is just fair in case like this. Should be natural. I don't have the red rubber ring, so I don't know if it fits for the job or not. The 5 long lever comes with certain advantages as a byproduct of its geometry. By pushing it to the end turns the knobwheel in exact 90 degree position, so the limiters only job is to keep it there until the next gearchange. of course I was experimenting with a 3L version, but did not satisfy me. Less accurate gear change, overall loss of reliability where it ended up. Still I encourage you to build it and experiment on it. One of the main benefit of this design is the smooth gearchange and the really small force that needs to operate it. Thanks for getting back.

Thanks for your sharing, and enjoy your holidays!

You are welcome, and thanks.

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After seeing many types of steppers, I can say, it's the best solution until now, in the single lever category. We have many paddle shifters, but a very few lever shifters. I wish, I had so good (so fast) stepper as this in my Porsche entry, but mine isn't. Thanks for sending me some days earlier the videos, to make some tests. I built IRL, and all what I can say, it works perfectly. No missed shifts, no big forces, just smooth and well done gear selecting.

Keep up the good work! :thumbup:

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Still I encourage you to build it and experiment on it.

I'm affraid I will :wink:, but only after building your version.

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I really like this. Nice and simple solution, that can fit with both motor and servo. Great work!!

-ED-

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that's a clever solution! even if i have to admit im not a big fan of rubber bands in lego for some reason lol

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I have been experimenting with this and my conclusion is also that you need a 5L lever to get the required reach. I don't have the special studded part with axle hole, so I had to use some different parts, but it works very smoothly. I used two red silicon bands, one wrapped twice around the limiter and one wrapped once around the stepper. I also added a block to avoid infinite shifting and I used a rubber connector (++) to get a better return to center effect in the manual version.

I also checked whether I could rotate the shifter axle without using the stepper and I could. It simply slips along the stepper (but maybe this is because I used different parts). This is nice because it means it can also be combined with HoG shifting like in my ultimate vwrsion of the Porsche.

@Attika, maybe you can confirm that your stepper also slips when the shifter axle is rotated from outside the stepper?

Edited by Didumos69

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Here you also see the intended slipping:

Edited by Didumos69

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Here you see the intended slipping:

Using different parts certanly changes its behaviour. I'm far from my parts, so a can't confirm how much difference it makes. If you use it with servo motor you wont be able to turn the axle as the motor works as a break on it. If it is used in a non motorised moc there isn't any torqe that causes non wanted gear change .

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If it is used in a non motorised moc there isn't any torqe that causes non wanted gear change .

I didn't really explain, slipping is particularly useful when a HoG shifter drives the axle with the knob gear directly. In that case the HoG generates the gear changing torque, not the stepper.

Edited by Didumos69

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I didn't really explain, slipping is particularly useful when a HoG shifter drives the axle with the knob gear directly. In that case the HoG generates the gear changing torque, not the stepper.

Well, I'm glad you find the slipping as an advantage, what I basically concidered as a disadvantage ;-) I've read your question in Sariel's topic. As I see his solution is more suitable for high torque tasks, as my gearbox frame in this form made for a lightweight 1:8 middle engine (let say) supercar what will be powered by 2 rc buggy motors. That will be my next moc. As It is a 4wd model my gearbox has a central diff as well. Due to these reasons it wasn't designed to be capable to break parts. As I was pointing it out in this post and the video I was going to demonstrate the concept of the stepper what could be built on various gearbox designs. The gearbox you see in this vid is just one and irrelevant as it is only an asset of demonstration. The other question was the size.... Sariel is about the same age as me therefore it feels kinda funny to compare who's got the bigger..... gearbox. :-D (yes, it is meant to be a joke ;-) )

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Thanks, this was the kind of comparison I was interested in. I already noticed the center diff, looking forward to seeing your next moc.

Regarding the gearbox size. They say performance is more important than size, but I'd say eventually all depends on who operates the gearbox :wink:.

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Thanks, this was the kind of comparison I was interested in. I already noticed the center diff, looking forward to seeing your next moc.

Regarding the gearbox size. They say performance is more important than size, but I'd say eventually all depends on who operates the gearbox :wink:.

This is the very first version of the stepper I came up with. Due to the lack of time (and the holyday) I didn't try to modify it yet. I'm sure with time it will evolve. Sariels solution has 3 years of development in it. My mechanism is barely a month old. No question that there is a difference in performance. My intention by sharing it in its early stage, to let others think on it and develop it. I belive that collaboration can take things further than contention.

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This is the very first version of the stepper I came up with. Due to the lack of time (and the holyday) I didn't try to modify it yet. I'm sure with time it will evolve. Sariels solution has 3 years of development in it. My mechanism is barely a month old. No question that there is a difference in performance.

I was actually extending your joke :wink:, but what you're saying makes sense.

I belive that collaboration can take things further than contention.

Which is very much appreciated! It operates so smooth that I can't stop playing with it. I have been driving my kids nuts with its clicking sound all over the weekend :wink:. I'm currently trying to figure out how I can use the same mechanism to redesign the PDK-unit - this thing where you've already won your spurs :wink: - in my ultimately playable version of the Porsche. This also explains why I see the slipping as advantage, as that version also features HoG shifting.

Edited by Didumos69

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I was actually extending your joke :wink:

Yes I got that.... :sweet: my brother laughed too when I read your reply to him.... Looking forward how will you implement it in the porsche

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Neat, Excellent work on making this. Looks like it works well. Lots of potential behind the Stepper mechanism here. Just One Question, how well does the stepper lock onto the knob gear? Thus, preventing the knob gear from unwanted rotation.

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Neat, Excellent work on making this. Looks like it works well. Lots of potential behind the Stepper mechanism here. Just One Question, how well does the stepper lock onto the knob gear? Thus, preventing the knob gear from unwanted rotation.

About unwanted rotation of the knob gear: The integrated limiter serves as a first line of defense; it makes sure the knob gear axle prefers to sit in perfect 90 degree orientations. It has proven useful in the 42056 Porsche to avoid double engaged gears. As for the exact locking behaviour of the complete stepper I think Attika has to answer himself. I have a slightly different implementation that is intended to slip through the stepper part.

Edited by Didumos69

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how well does the stepper lock onto the knob gear? Thus, preventing the knob gear from unwanted rotation.

Hi, as I wrote a couple of lines above if you use it a non motorised model there isn't enough countertorque to get it out from the gear. If you motorise it, using either servo motor or pf m motor with return to center mechanism, both holds the lever strong enough to prevent unwanted gearchange. I hope if you watch over the video concidering this explanation you will recognise the effect I wrote and the physics vehind it. I'm abroad right now therefore unable to post a video that highlights this. As you wrote this is a concept only so theres plenty of room to develop it to match certain requirements. Don't hesitate build it and experiment on it. You are free to use and modify it to your own taste. Thanks for poping in.

By the way I'd be happy to see if you can improve it in any manner. And this applies on every reader. ;-) And now let me finish my beer :-D

Edited by Attika

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