The subject innovation relates to the Defense door provided with a chain tension compensation device, is vertically installed on the exit sides of the building structure with guide rails 12, guide post 10 and, on both sides of the upper column to be elevated along the guide rail the guide roller 21 and the bottom guide roller 22, the door panel 20, the guide posts 10, the left side provided in the upper support panel 31 and the right support panel 32 having on one side of the bottom and, the support and the drive motor (M) provided on one of the support panels of the panel, the left side support panel 31 and the right support panel (32) cross in correspondence to be installed a power transmission shaft 33 through the drive motor on and connection chain 34, the lifting sprocket 35 for driving a drive force of, and one end is fixed from the left side support panel 31 and the right supporting panels 32, the longitudinal direction are respectively coupled to both sides of the room of the door panel fixed and elevating switch through the sprocket 35, It is installed in the door opening and closing drive means consisting of a feed chain 36 for driving the panel 20, 30 and the left support panel 31 and the right support panel 32 supported by the lifting sprockets 35 the lower portion of be superimposed on the door panel 20 to be transported toward the panel before and after the folding guide for the plate 40, the left support panel 31 and the right support panel is installed on the lower side of 32 the door panel 20 in the side door to the Defense consisting of guide member 50 to guide the side guide in sequence or guide plate 40 to the guide rail 12,
Move to the side of the lifting sprocket 35 from the closed when the guide plate 40 of the Defense door, or vice versa, the end door channel 20 side feed to go to the guide plate 40 from lifting sprocket during opening of Defense door chain tensioning means (200) for preventing contact of the conveying chain 36 from sagging prevention and guide member 50 of the chain 36 are mutually corresponding to the left side support panel 31 and the right supporting panels 32, the close to the feed chain which supports the end door panel of the door panel placed, is arranged respectively to the bar, characterized in, from the left and right support panel side, which is provided as the chain tension adjustment means to the final guide rail or the first opening in the process is made by giving to move to compensate for the tension without sagging, jam, wear Na2 friction from the guide member side by the interference of the feed chain, noise, It is provided to eliminate the effect of opening and closing of the door is successfully Defense.