Z-Motor Brake for 3D-printers with NEMA17 steppers

Z-motor brake that prevents build plate from sinking by it's own weight, when power is off the Z-stepper. This can be useful during filament change and recovery after power loss.
(A version for Ender-4, Integrated with Z-motor mount, can be found at https://www.thingiverse.com/thing:3449383)

Brake arms are mounted floating, so there should be no influence on printing quality.

Mounting:
Assembled Z-Motor Brake with 2 x M3 x 18 and 2 x M3 nuts. Be sure everything moves freely.
Unscrew tw