The utility model discloses a pusher jack, the on -line screen storage device comprises a base, be equipped with the slide on the base, the slide is located along clockwise slope setting in the slide it has a power device to hinge on the base, a power device's execution end pushes away smooth pole through hinged member is articulated, initial condition, hinged member with the both sides of slide set up perpendicularly. Adopting this pusher jack, through the slope setting of slide, having guaranteed to push away in the slant all the time of smooth pole or the level motion, restricted pushing away smooth pole downward swinging, effectively prevented the scraper conveyor gliding, simple structure uses reliably, and the antiskid is effectual, lays a good foundation to specific locations and normal exploitation work for guaranteeing the smooth propelling movement of scraper conveyor.