Gravity automatic chain tensioning device

The utility model discloses a gravity automatic chain tensioning device, which relates to the technical field of chain tensioning of a zinc ingot casting production line, and comprises a rack, an ingot casting machine head pulley, an ingot casting machine chain and a zinc ingot, the left side of the rack is fixedly provided with a first rotating shaft, the inner side of the rack is fixedly connected with a support frame, and the upper end surface of the support frame is fixedly provided with a second rotating shaft; fixed frames are fixedly connected to the front side and the rear side of the rack, a third rotating shaft is fixedly installed between the two fixed frames, movable frames are rotationally connected to the outer sides of the two fixed frames, fourth rotating shafts are fixedly installed on the outer sides of the movable frames, and balancing weights are arranged at the upper ends of the movable frames; a plurality of tensioning chains sleeve the outer sides of the first rotating shaft, the second