Input: yellow crank (fixed to the yellow disk). The disk has Archimedean spiral rib that engages with red rack. Parameters of the spiral must be chosen to maintain the self-locking transmission.
To lower the jack quickly, move the gear out of the blue rack by releasing the blue eccentric cam.
This jack is used for low loads. According to the Law of Conservation of work:
Work used to turn the crank = work to move the rack
2*Pi*R*F = Q*P
F: force applied to the crank
G: load applied to the rack
Pi = 3.142
R: the crank radius
P: the rack pitch Mechanical advantage Ma = Q/F = 2*Pi*R/P
If P = 20 mm; R = 150 mm then Ma = 47.13
