Improvements in revolving doors

187,740. Colman, T. B. Aug. 8, 1921. Revolving doors.-Revolving compartment doors have wings adapted to collapse when subjected to abnormal pressure. Each wing consists of two universally-hinged parts 1<a>, 1<b>, the part 1<b> being hinged on ball-bearings between collars 2b, Fig. 8, on a shaft or column carried by a beam above the rotating soffit. The wings are held in the central position by spring-pressed studs 12, Fig. 4, carried by a plate on the central ballbearing of the soffit and engaging open-ended slots 11 in the top edge of each wing-member 1<a>, and by spring-pressed studs adapted to engage recesses in a pivoted plate at the axis of the door and at ground level. Additional support may be provided by arms pivoted to the soffit and having pin-and-slot engagement with the door. Alternative means for holding the wings in the central position comprise arms 25, Fig. 14, having studs engaging a plate rotatably mounted on a casting in the ground and having a pin-and-slot connection with the 'bottom edge of the door. The wing is allowed to fold under abnormal pressure by means of a cam-guide on the pin 28 engaging the holding rod 25 and raising same when the wing parts are folded. The wings may be supported on arcshaped guideways 33, Fig. 13b, by pins 36 con. nected to an undercut slot in the door and having a ball-bearing on the rails. The columns 2<a>, Fig. 6, have an adjustable bolt 17 connected to an arcshaped piece 13 housed in a ring 14 sunk in the ground, the pieces 13 being connected by segments forming a closed ring, so that the columns move together. Woodwork carrying draught-excluding means is attached to the hinges 2. A spring-controlled yielding latch 39 connects opposite pairs of wings together, Fig. 15; on first moving the wings apart, the latch is drawn along the pin 41 against the spring 44 until the camshaped slot 42 and pin 40 free the latch from the engaging recess 43.