You need 6x “Link”, 6x “Shovel” and 2x “Spyder”.

All parts screw together with M3 bolts and lock nuts. Don't tighten them to hard, the joints have to move freely.

Attach a string to each Spyder parts. Thread the string from the lower spyder through the hole in the center of the upper spyder. This thread is used to control opening and closing of the claw. Use the string attached to the top spyder to lift the claw up and down.

You might need to add some weight to the Spyder parts for them to move realistically.