| 摘要 |
PURPOSE: A hinge device for a drop down-type door is provided to allow immediate repairs as users tighten a control spring using a wrench even if the control spring is stretched by a door. CONSTITUTION: A hinge device for a drop down-type door comprises a main frame(10), an auxiliary frame(20), a wrench bolt(60), and a control spring(S1). A through hole(14) is formed on the center of the sealed upper part of the main frame. A nut is fixed to a part which corresponds to the through hole of the main frame inside of a support hole(23). The wrench bolt is fitted into the through hole of the main frame, and the leading end of the wrench bolt is coupled to the fixed nut. The control spring is elastically installed between the head of the wrench bolt and the through hole of the main frame. The auxiliary frame is loosened or pulled by the wrench bolt, and the tension of the control spring is adjusted.
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