8 Speed Gearbox using just two levers/selectors - for @SNIPE

[TechnicBrickPower]

 

Here I present an 8 speed gearbox that does the seemingly impossible - creating eight speeds using just two levers/selectors. Normally two selectors are used to create a 4 speed gearbox - however this design allows for 1 of 8 different speeds to be selected - thanks for the idea @SNIPE

 

[Jeroen Ottens]

Very ingenious! The operation is not really intuitive, but if you would use (PU-)motors to drive the gearselectors you can hide that in SW. Since the order of switching is fixed it should be theoritically possible to even do this with one motor and some fancy mechanism to switch the levers...

Still, I like it a lot.

[chlego]

WHOOOOOOOW! This is so smart, mainly because of this:

-8 speed with 2 levers 

-very compact

-no need for the orange parts (which I don't own)

Superb design! Will you make instructions?

[2GodBDGlory]

Wow! That is very clever!

I would still expect that traditional 2x4 8-speeds are going to be more practical in MOCs, but I understand that that is not really what you were aiming for, anyway.

It is interesting how it adds speeds, rather than multiplying them.

I always like seeing interesting gearboxes, so keep up the good work!

[Zerobricks]

It's basically using two 2 speed gearbox and averaging the combinations with a differential, using worm gersr to prevent power being sent back. Did I get it right?

Edited September 4, 2020 by Zerobricks

[SNIPE]

Thanks @TechnicBrickPower and everyone in this thread. Now for me to work on using it with the orange rotary shifters and making it more compact

[TechnicBrickPower]

On 9/5/2020 at 1:26 AM, chlego said:

WHOOOOOOOW! This is so smart, mainly because of this:

-8 speed with 2 levers 

-very compact

-no need for the orange parts (which I don't own)

Superb design! Will you make instructions?

 

Yes here they are!

https://rebrickable.com/mocs/MOC-51409/TechnicBrickPower/8-speed-geabox-using-just-2-levers

[SNIPE]

Hi,

I'd like to also disguss an alternate way of making this:

The differential allows input A to drive the output but not backflow the drive to input B

And vice versa, it allows input B to drive the output but not backflow the drive to input A

And finally it does not allow both A and B to both drive it at the same time.

And the best thing, compared to using that OR gate from the 9396 helcipter is that it does not use clockwise/counterclockwise rotation as I/0 , it uses spinning/not spinning as I/0, so this will make it easier to add the axle for reverse gear, from the external D-N-R shifter.

Here is the differential idea, im not sure if its acting as OR, XOR, or tristate here but heh:

And here is the gearbox, when its built (i've tested it IRL already) all 8 positions work without jamming) but some ratios are repeated so I need to figure out a way to fix that, Maybe using an 8 and/or 20 tooth gear with the 24 tooth side of the differential will get more speeds:


Here is the LDR file.

So the idea here is to have  (12+20, 20+12, 8 + 24, 24+8 but then add either an 8 or 20 tooth gear to the differential thus giving 4 more ratios:

8 + 24  and 8 + 24

24 + 8 and 24 + 8

12 + 20 and 24 + 8

20 + 12 and 24 + 8

Or assuming im using a 20 tooth with the 24tooth part of the diff:

8 + 24  and 20 + 24

24 + 8 and 24 + 20

12 + 20 and 24 + 20

20 + 12 and 24 + 20

Currently I only have a 16+ diff16 hooked up so I think thats just repeating the first 4 (12+20, 20+12, 8 + 24, 24+8) ratios.

Regards, Snipe.

Edited October 16, 2021 by SNIPE