Truck box cover device extended and retracted in transmission manner

A truck box cover device extended and retracted in a transmission manner, comprising a clutch type driving gearbox, a roller shutter shaft, a roller shutter cover and roller shutter cover rail support frames, wherein

• the clutch type driving gearbox is connected with the roller shutter shaft to drive the roller shutter shaft to rotate in a forward/reverse manner or stop rotating;
• the roller shutter shaft is stripped winding shaft and comprises a transmission end and a roller shutter cover mounting shaft;
• one end of the transmission end is connected with the clutch type driving gearbox and is driven by the clutch type driving gearbox to correspondingly rotate, and the other end is connected to the roller shutter cover mounting shaft, one end, away from the transmission end, of the roller shutter cover mounting shaft is fixed to the interior of a driven bearing;
• one end of the roller shutter cover is fixed to the roller shutter shaft, and the other end retracts in an extension direction of the roller shutter cover rail support frame;
• the roller shutter cover rail support frames are vertically and oppositely located on two sides of the roller shutter cover mounting shaft;
• a rail slot is formed in an inner side wall in a retraction direction of the roller shutter cover;
• the two rail slots are located in two sides of the roller shutter cover in the retraction direction;
• outer sides of the roller shutter cover rail support frames fit for two side walls of an opened top cover in a truck box.