Link to the video if you want to see how this mechanism works: https://www.youtube.com/watch?v=GEGb_TDZdro
This mechanism is dedicated to one of the characters in films about X-Men - Wolverine. These "Сlaws" can be extended and retracted. To operate the mechanism, a servo-drive converted to a DC motor was used. Claws are advanced using metal threads that are wound on a special reel. The mechanism is activated using a special button. One claw length 210 mm. If you have questions, please write in the comments. If necessary, I can shoot a video how to assemble this mechanism.
This object was made in Tinkercad. https://www.tinkercad.com/things/f1z68dFivb0