Liquefied natural gas unloading arm quick coupling device

The invention discloses a liquefied natural gas unloading arm quick coupling device. The device comprises a quick coupling mechanism. The quick coupling mechanism comprises: a rotating disc, rotationally arranged on a fixed disc in a sleeving mode, wherein the bottom ends of multiple sets of synchronous telescopic rod pieces are arranged on the rotating disc in the circumferential direction at intervals, and the upper portions of the multiple sets of synchronous telescopic rod pieces are arranged on a flange pipeline in the circumferential direction at intervals, so that the multiple sets of synchronous telescopic rod pieces can simultaneously extend upwards or contract downwards at the same amplitude; and a plurality of clamping pressing blocks, wherein each clamping pressing block is arranged at the top end of the corresponding synchronous telescopic rod piece, and the clamping pressing blocks extend towards the center line of the flange pipeline to form an arc-shaped expanded end face. The invention disclo