Folding Gravity Grappling Hook Keyring

Introducing a folding gravity hook keychain, which opens and closes due to gravity.

The system consists of only 5 pieces:
- Arm_A (2x)
- Arm_B (1x)
- Clip_A (2x)
- Clip_B (1x)
- Pin_3.8mm (3x)
- Pin_4mm

The Arm_B and Clip_B parts have the pin holes with more tolerance, this way, the pin stays fixed with the other parts and allows it to rotate freely on it.

I have designed two models of pins, depending on the printing tolerance of your printer. In my case, the perfect fit is with the 3.8mm radius pin. In case none of the pins work, leave a comment and I will be happy to upload a new pin with the perfect tolerance for you.

In the prototype in the picture, I used M4 screws. Any option is valid.

In my case, it allows to hold more than 8kg, I have not tested it to failure, I leave that to you!

Let me know in the comments if you create your keychain! Thanks to all of you!