Free Wheel and Flex Coupler

[JM1971]

There's a better way to ease bumpy motor starts....Just use a differential with housing conencted via gear to a spring, like hockey spring....Should work good.

That's a good idea, will try that with a shock.

[Lipko]

I want a small and strong solution. Of course, I want to work on that, it's just the thread called out for some idea tossing.

[Splat]

I built the Free Wheel a little while ago as pictured in the first post of this thread, and wasn't too happy with the results (see here).

This weekend I decided to give it another go, and modify the design a little bit to remove what I saw as the 'problems' with the original design.

I have increased the length of the mechanism by another 2 studs, which allowed me to reinforce some of the axles/gears and Axle Connector Double Flexible (Rubber) pieces. I also removed one of the 8 tooth gears/rubber pieces, as 8 is not divisible by 3, and therefore it was throwing off the alignment and making the mechanism shake. Lastly, I have also inserted a 3x3 Disk inside the wheel so that the 8 tooth gears don't get caught in the holes of the wheel.

I have made a quick video of my modified design in action:

@DrJB - If you still think that it runs fine without these modifications, I would love to see a video of it in action.

Edited April 14, 2014 by Splat

[aol000xw]

It works nicely.

[DrJB]

@Splat: Beautifully done. Between business trips and fatherhood, I had completely forgotten about this thread. You have a very valid point in that by using 3× 8t gears, the three rubber elements cannot be 'aligned' and thus, they will not grab at the 'same' time, and will cause some vibration. Nicely done again.

[OzShan]

Very cool thread. I also like reproducing 'real life' mechanisms in technic.

On the topic of gear thrashing some of you mentioned (and perhaps backlash too) does anybody know if TLG has looked at including small toothed belts and pulleys? There are so many different small belts made for printers etc that maybe it wouldn't be too expensive?

[DrJB]

The only one I can think of is this:

http://www.bricklink...sp?P=32089&in=S

http://www.bricklink...asp?P=x428&in=S

It's a toothed pulley that goes with special belts/tracks, though they were only released in 2 different sets ...

Edited April 16, 2014 by DrJB

[OzShan]

Thanks. I did a little more searching for different sized sprockets to match, but that one and some different types are all that was returned. A bit hard to build a drive train now, but I guess there is always hope for future inclusions. Hope it worked out for then to release those parts for just those sets!

Anyway, I digress. Cool clutches

[mescalinum]

You could use backwards motor rotation to action a brake

[DrJB]

Just found this on youtube. Apparently a lego fan built the contraption and made a small video of it. And, he even referenced this thread, cool!

http://computerbackup.vidlify.net/en/video/pGgv7VNb6Nk/Lego-Technic-Free-Wheel

[Splat]

@DrJB - Um, that is my video, the same one that I posted above, they just embedded the video in their webpage. I'm happy to give credit where I can, and mentioned both piterx and yourself in the video description.

On Eurobricks I go by the alias 'Splat', but in most other places on the web I go by the alias 'slfroden' - see links in my signature.

[brodriguez]

I am using a sprag clutch for a school project and would like to scale it down using legos.

Could you post a manual on how to build your design? Or the pieces used?

I appreciate you sharing,

 

[dellock6]

Hi,
I'm studying this clutch myself for a project, and the youtube video posted before is really useful to understand both the behvior and the pieces. Probably the only one that is not so immediate to find is the wheel, but I believe is the part 60208:

http://www.bricklink.com/v2/catalog/catalogitem.page?P=60208&name=Wheel 31mm D. x 15mm Technic&category=[Wheel]#T=S&O={"ss":"IT"}

I'm designing the clutch on stud.io but sadly it has not this part (not even any Power Function piece, which is annoying) so I cannot test the alignment with the rest of the pieces.

Luca