Safety protection device for long material opening of overhanging type discharging platform

The utility model discloses a safety protection device for a long material opening of an overhanging type discharging platform. The safety protection device comprises a U-shaped frame. The U-shaped frame is composed of two side frames and a bottom frame, and grooves of the two side frames of the U-shaped section are opposite. Pulley assemblies and angle steel are installed in the grooves of the side frames, the pulley assemblies are located at the tops of the side frames, and the angle steel is located below the pulley assemblies. And the groove of the side frame is divided into a vertical groove and a vertical slideway by the angle steel. And a protective plate is arranged in the vertical slideways of the two side frames in a sliding manner. One end of the steel wire rope bypasses the pulley assembly and then is connected with the top of the side edge of the protection plate, the other end of the steel wire rope extends downwards along the vertical groove and is connected with the topend of the extension spr