Vòng & Cầu Co Giãn (Expanding Rings & Spheres)

I was inspired by @BCE_Gatien's awesome Hoberman Sphere, but wanted smaller pieces and a different attachment mechanism.  The parts here can be combined to make multiple sizes and versions of expanding rings, spheres, etc.  I recommend starting with a 12gon ring, which can be easily adapted into a sphere.

Printing

• PETG
• Brim: for hubs only
• Infill: gyroid/15%
• Supports: none

Assembly

Rings

12gon ring

1. 12 copies of 12gon_A 
2. 12 copies of 12gon_B
3. 36 copies of lock (recommended)
4. attach the middle of one 12gon_A to the middle of one 12gon_B (optional: lock).  This makes one scissor mechanism
5. attach the 12 scissors together to form a ring, ensuring that each scissor's orientation and spacing is the same as the others (optional: lock)

Other rings

1. Repeat instructions above after a global replace of 12 with the gon you're using (ex; print 5 copies each of 5gon_A&B, 5*3 = 15 copies of lock)

Spheres

General

Spheres are multiple rings held together with hubs.

1. Create strings of scissors as you did for creating rings, but create only partial circles (arcs) 
2. At the end of each arc, replace the final A piece with an L or and R piece, such that each side of the end has a peg facing inward
3. Attach each end of the arc to a hub - each arc will be connected to 4 hubs, each hub will connect to 4 arcs
4. Attach further arcs to the hubs

Sphere Types

• Simple - 3 x 12gon rings at 90 degrees to each other
  • 12 x 12gon_A
  • 36 x 12gon_B
  • 12 x  12gon_L
  • 12 x  12gon_R
  • 12 x 90_hubs
• Icosadodecahedron - the traditional Hoberman sphere, 6 x 10gon rings 
  • This doesn't work yet! I need some help with math :)
  • 60 x 10gon_B
  • 60 x 10gon_C
  • 60 x 60_hubs
  • For this model I'm attaching all scissors directly to hubs (so no A parts) - for more expansion we could try a 20gon or 30gon
• Plenty of other shapes to try!

Naming

• Strut files are named Ngon_X
  • N is the number of sides of the regular polygon formed by the strut
  • X defines the type of part:
    • A - 3 holes
    • B - 3 pegs
    • C - 1 peg, 1 hole, 1 peg
    • L - 1 peg, 2 holes
    • R - 2 holes, 1 peg (mirror of L)
• Hub files are named hub_N
  • N is the internal angle in degrees
• Lock
  • A simple lock, which snaps in place on pegs and holds pieces together 

Please ask me for additional sizes and shapes!