Abstract: An improved astragal assembly for use with a double door installation includes an astragal strip secured along the vertical edge of the inactive door. A lock block is slidably disposed in at least one end of said astragal strip and can be moved between an extended position for securing the door and a retracted position for freeing the door. The lock block has a projecting bolt receivable in a receptacle in the door frame when the lock block is slid to its extended position. A gasket is secured to the end of the lock block and the bolt passes through an opening in the gasket. The gasket engages and seals against the door frame when the lock block is in its extended position. Gaskets are also provided on the sides of the lock block for engaging and sealing against the doors of the double door installation. When the doors are closed and secured in place, the lock block and gasket assembly prevents drafts from flowing under the door installation beneath the astragal thereof.

Abstract: A selectively positionable extension for an elevated walkway includes a planar ramp mounted by rollers to a frame and coupled to the frame by a selectively extensible hydraulic ram. The frame itself is supported by a second ramp for controlled vertical positioning. A pair of handrail gates are pivotally mounted on the ramp frame at opposed lateral sides thereof, and engage guide channels in the ramp side edges for automatically opening and closing the handrail gates as the ramp is extended from and retracted into the frame. The guide channels are so constructed that the handrail gates open and close from overlapping positions without interference. The entire extension is provided as a modular assembly which may be readily incorporated into existing or new walkway constructions.

Abstract: An improved ventilation opening having a separate screen frame which is attached to the ventilation opening by pawls mounted on pawl arms, with the pawls inserted into pawl receiving openings in a crossbar on the ventilation opening and having means to more positively retain the pawls within their respective pawl openings.

Abstract: An apparatus is described for regulating the closing sequence of double doors, each of which is provided with a floor-mounted door closer. In this arrangement an actuating unit is integrated into the floor-mounted door closer associated with the trailing door and controls a valve unit in the floor-mounted door closer associated with the leading door, preferably via a Bowden cable. The Bowden cable is laid in the ground so that no parts need to be installed on the door or door frame.

Abstract: A manway cover is formed using two like door panels made of lightweight, corrosion-resistant material which are hand operable from either side of the manway and can be installed without tools.