Abstract: A panic exit device has an improved linkage between the push bar and the push bar housing so that no significant horizontal or sideways movement of the push bar occurs as it is pushed inward to unlatch the door. Each linkage employs a link having one linear and one curved slot to smoothly guide the push bar whenever the push bar is pressed inwardly. The device further features a fail-safe dogging mechanism so that the push bar cannot be unintentionally dogged. A fail-safe clip is moved out of an interfering position with the dogging element only when the push bar is moved to unlatch the door.

Abstract: A hydraulically controlled pneumatic swinging door operator comprising a pneumatic cylinder with a piston therein, a continuous loop connected to opposite sides of the piston and entrained at its ends over sprockets, one of which makes driving or driven connection with a door, a passive hydraulic system including a cylinder and a piston, the piston of which is carried by the side of the loop opposite the side carrying the pneumatic piston, and passage work in the hydraulic system for controlling the flow of hydraulic fluid in said cylinder from one side of the hydraulic piston to the other side.