Expanding Circle - Hoberman - With a core and expansion arms

Expanding Circle - Hoberman - With a core and 4 expansion arms.
8 full segments (16 pieces), so angles are 135 degrees, made into arcs.
Only allows for about 1/2 contraction, core has diameter of 1/3 the outer circle, expansion arms are slightly longer so that they stop just outside the core.
This is the first prototype I made from plastic cardboard and wooden dowels for use in an expanding-gear CVT Transmission idea for human powered vehicles. Here is a link to that project using 3D printed parts: • CVT Automatic Mechanic...
The Inner Pivot Points with the dowels in this example are replaced by pins with small sprockets that connect to a standard bike chain, and on the other end of these pins there are Ratchets so that the Sprockets can lock in the forward moving direction, but spin freely back along the chain (or vice versa) when the expanding circle expands or contracts (oterhwise the chain would lock the pins with the sprockets in place).
This 'expanding circle' would be (most likely) mounted on the front, crank gear of the bicycle, which would be prevented from contracting due to applied torque by resistance spring(s). I played around with various versions of spring resistance ideas, the most recent being a clock spring between the crank arm and the central core disc.
I reached a stopping point on this project in 2022 due to running out of money needed to continue working on this, as I would need to move to metal part production to make sure it works correctly. If anyone is interested in continuing the work on this project let me know. :)
Here is a link to a Google Drive folder with all related project files for the CVT Transmission project idea, including the 3D models (made using Google SketchUp): drive.google.com/drive/u/2/fo...

[@connected.]

The algorithm has heard that your video is awesome

[@Lone_wolf--br7fi]

I can definitely see this having application in the aerospace field

[@SongMom8]

The Hoberman Arch was first used at the Salt Lake City winter Olympics.

[@tortoise62]

I've been looking for something like this to wind network patch cables while also giving a clue to the cable's length. (Pi x diameter = circumference)
- A 6' cable would need 4-6" diameter loops. (3.14 x 6" x 4 loops = 75.35" /12" per ft = 6.28 ft)
- A 10' cable would need 4-10" diameter loops.
- A 25' cable would need 8-12" diameter loops.

[@salsasalsa943]

do you have a tutorial for this?

[@prakkari]

I think this can be applicable to a tire that changes from a road tire to an off road tire in a jiffy. Sports car to a tank in seconds. :)

[@Gunzee]

Does it expand though? Every other outer pivot is fixed.
Kinda reminds me of a spring free centrifugal clutch. Nice design and nice to see is not 3D printed.

[@ramzifraj4325]

please more ideas for this project

[@srmstm1077]

👍👍👍👍

[@jorgeih]

very interesting. it looks like you didn't take the project forward... did you manage to materialize this in metal?

[@tekknojunkie]

This is part of a larger transmission design idea, still in progress, have 3D printed and CNC milled parts, this plastic cardboard cutout was the first sketch concept :)

[@juanclavel644]

🤔 es como si me recordase a un obturador de cámara fotográfica analógica

[@CisnerosShop]

Do you have any build plans for this?

[@rdmotors40]

Here is a link to a Google Drive folder with all related project files, including the 3D models (made using Google SketchUp): drive.google.com/drive/u/2/folders/11x6O-zWBdPNOR2aGSTErfoqPnSmVUtMd

[@jibrilchannel2765]

Its not expanding its changing shape