Pinion 1 rotates about fixed axis A and meshes with rack teeth b on the right-hand side of link 2 which slides vertically in guide a. When pinion 1 is rotated clockwise, link 2 is raised. Link 2 is held in the raised position by pawl 3 which turns about fixed axis B and engages ratchet teeth d on the left-hand side of link 2.
$2399$SG,MH$