Abstract: A lock located within a door has a bolt that is extended and retracted by a double acting air cylinder. A single air line extends from the door frame and into the door where it is connected with a valve having two discharge lines that lead to opposite ends of the cylinder. To energize the cylinder and move the lock bolt, a charge of pressurized air is directed to the valve which in turn directs it to one end of the cylinder. The charge of air further causes the valve to reset itself so that the next charge will be directed to the opposite end of the cylinder. Consequently, with successive charges of air the piston rod of the cylinder and the lock bolt move in opposite directions.

Abstract: A lock has a lock cylinder provided with a rotatable core which is normally prevented from rotating by drivers that bridge the shear line between the core and the main body of the cylinder. However, when either first or second keys are inserted into the core, pins within the core are elevated to the shear line so that the drivers no longer prevent rotation of the core. The main body of the cylinder also contains a push rod which is urged into the core by an actuator when the actuator is energized, but is otherwise located out of the core with its inner end flush with the shear line. The core also contains a pin which aligns with the push rod. The first key is incapable of moving the push rod out of the core so that the core may be turned with the first key only when the actuator is de-energized. The second key, however, forces the pin associated with the push rod against the push rod and moves the push rod outwardly to the shear line, even when the actuator is energized.

Abstract: A pocket door is moved between open and closed positions by an electric motor unit mounted on the studs framing the rough opening in which the door is installed. The rotary motion of the motor is translated into linear motion by a cable and pulley arrangement with one of the pulleys being a drive pulley on the shaft of the motor unit and the other being an idler pulley mounted on the track on which the door slides. The cable is attached to the door through a coil-type tension spring. Hence, the door will move when the motor is energized and should the door encounter an impediment upon closing the spring will expand and permit the pulley to slip within the loop of the cable. The motor is controlled by a timer which when activated causes the motor to run for sufficient time to open the door, then hold to enable one to pass through the door opening, and then run in the opposite direction for sufficient time to close the door.

Abstract: Metal contained within soil is separated therefrom by introducing the soil into a tank containing water which is quite turbulent, the turbulence being generated by the fact that the water is introduced into the tank in a swirl and also directly upwardly through the center of the swirl. Vibrator units on the sidewalls of the tank further add to the turbulence. Upon being introduced into the turbulent water, the soil quickly turns to mud which goes into suspension and the suspension so formed is buoyed upwardly by the incoming clean water which rises through the tank. The suspension overflows the tank and is directed to a settling basin where the mud is allowed to settle out. The clean water which remains is recirculated through the tank. The metal, on the other hand, being considerably heavier than the mud, passes downwardly through the tank where it is thoroughly washed by the incoming water. The washed metal passes out of the bottom of the tank and is elevated upwardly by a screw-type conveyor.

Abstract: A door closer has an air cylinder which, when pressurized, neutralizes the door closing force applied by the closer so that the door will open with relative ease. The air cylinder is pressurized through a valve which is contained within the door and is operated by a handle on the door.

Abstract: A door is provided with an air-operated lock including a base structure mounted on the door adjacent the free vertical edge thereof, a bolt pivoted on the base structure for movement between retracted and extended positions, and an air cylinder between the base structure and the bolt for moving the bolt to its extended position. The air line from the lock passes from the door to the frame through a hinge capable of transmitting pressurized air.

Abstract: A pivot arrangement at the upper end of a pivot door includes a bushing on the door and a hollow pivot pin projected from the door frame header into the bushing. Fluid conduits are connected with the pin and the bushing so that the conduits are in communication through the pivot arrangement. Pressurized air is transmitted through the conduits and pivot arrangement to a pneumatic appliance on the door.

Abstract: Two or more doors leading to a single room are provided with electrically operated locks which are energized by depressing a button in the room. All of the locks are de-energized by opening either of the doors, so that access to the room is available through either of the door openings when the room is not occupied.

Abstract: An exit fixture for a door is connected with the lock on the door and includes manually operated means which when depressed retracts the bolt of the lock, thereby releasing the door. Springs act upon the manually operated means to restore the manually operated means to its original position wherein the bolt will again project from the door. A bellows or other pneumatic device when filled with pressurized air overcomes the force exerted by the springs so as to allow the manually operated means to assume the position in which the latch bolt is retracted, thus permitting the door to be opened and closed without operating the lock.