Seat mechanical lock with restoring force

The utility model relates to a seat mechanical lock with restoring force. The seat mechanical lock comprises a lock frame, a sleeve, a lock shaft, a piston, a first spring, a second spring, a pressing mechanism and a pull rope. A transverse through hole and a vertical through hole which are perpendicular are formed in the lock frame, one end of the sleeve is fixed to the lock frame, a through hole in the sleeve is communicated with the vertical through hole, the piston is arranged in the transverse through hole, a through hole is formed in the lateral side of the piston, the lock shaft is matched with the vertical through hole and penetrates through the through hole of the piston, the pressing mechanism is arranged on the left side of the piston, the first spring is arranged on the right side of the piston, the pull rope is connected with the pressing mechanism and can control the pressing mechanism to rightwards push the piston, the second spring is arranged on the lock shaft in a sleeving mode, the lower end of the second spring and the top of the lock frame are fixed, and the upper end of the second spring and the top of the lock shaft are fixed. By means of the seat mechanical lock, a backrest can be locked and unlocked, bidirectional stressing can be achieved, the restoring force can be provided in the use process, and the seat mechanical lock is light, handy, reliable and convenient to operate.