Chain type flexible mechanical arm suitable for underwater automatic video inspection of reactor internals

The invention relates to a chain type flexible mechanical arm suitable for underwater automatic video inspection of an reactor internals. The chain type flexible mechanical arm comprises a lifting mechanism, a telescopic mechanism and a chain type mechanical arm body; the lifting mechanism comprises a lifting motor; the lower end of the lifting motor is connected to a lifting screw rod, and the lifting screw rod is sleeved with a lifting nut B; the lifting nut B is connected to the telescopic mechanism through a connecting piece; the lifting motor drives the lifting screw rod to rotate and drives the nut B slide up and down along the lifting screw rod so as to drive the telescopic mechanism to move up and down; the telescopic mechanism moves in the vertical direction along a lifting guiderail under the guidance of a lifting guide device and a lifting guide rail; the lifting guide device is fixed on a shell of the telescopic mechanism; and the lifting guide rail is fixed on a machine frame of the lifting mecha