Self-locking mechanism and lift chair therewith

A lift chair, comprising:

• a base (82);
• and
• a self-locking mechanism, comprising:
• a frame (1), configured to move relative to the base;
• a supporting member (6), configured to move relative to the frame (1);
• a rear rotating member (2), having an upper end rotatably connected with the supporting member (6), a lower end provided with a guide slot (22), and a middle portion between the upper end and the lower end;
• a rear transmission member (3), having a first end rotatably connected with the frame (1), and a second end rotatably connected with the middle portion of the rear rotating member (2);
• and
• a locking rod (4), having an upper end rotatably connected with the frame (1), and a lower end provided with a guide rod (41), wherein the guide rod (41) is movable in the guide slot (22);
• wherein the frame (1), the rear transmission member (3), the rear rotating member (2) and the locking rod (4) form a four-bar linkage mechanism;
• and
• wherein the locking rod (4) is rotatable between a plurality of positions, the positions comprise a plurality of locking positions, and when the locking rod (4) is in each of the locking positions, the guide rod (41) abuts against a bottom end of the guide slot (22) to prevent the supporting member (6) from moving upward.