Abstract: An improved steel rolling door is equipped with a a number of pivot plates which are engaged with each other side by side and pivotally associated with one side of the topmost collapsible door plate, and a plurality of pulling wires which are engaged with the opposite side thereof so as to permit the collapsible door plates to be adjusted from a horizontal position to a vertical position, i.e., from an opening position to a closing position, or vice versa. Moreover, the door plates are consecutively connected to each other one by one by way of a plurality of linking pieces and length variable linkage assembly units each including a pair of pivot parts and a connector so that the door plates can be easily and smoothly collapsed and rolled up along a rolling shaft without getting stuck in operation.

Abstract: An iron rolling door including a rolling door board structure and guide rails. The rolling door board structure is composed of multiple support rods, metal plates, connecting plates and stopper plates. Two ends of each metal plate is wound to define two circular holes through which the support rods extend. Each two adjacent metal plates are pivotally connected by the connecting plate, whereby the metal plates are able to rotate through a certain angle into an opened Or closed state. The stopper plates are fitted with the support rods for preventing the metal plates from slipping away from the support rods. Each guide rail has a guiding wall defining a guiding groove for receiving a slide plate. Two link members are disposed between the slide plate and the guiding wall and an extension spring is disposed between the link member and guiding wall.