Abstract: A power window apparatus with a safety device capable of taking a safety measure when it detects the neck or hand of a passenger being caught in the window, which device can exactly detect such a dangerous state and take a reliable safety measure to correct for the same, irrespective of variations of ambient temperature. A temperature sensor provided which senses the temperature of the motor acting as a drive source for moving the window. This temperature is closely related to the ambient temperature. A reference value for the motor speed for detecting an object-caught state is altered according to the detected temperature, thereby providing exact detection of the object-caught state irrespective of temperature variations. Preferably, the power transmission for the window, the temperature sensor, and a controller structure are mounted on an inner side of a single housing.

Abstract: The system includes a vestibule and a plurality of emergency exits interconnecting the secure area with the outside environment. The vestibule comprises a pair of security doors and the emergency exits comprise security doors having locking means and means for disabling the locking means in response to any one of several preselected egress corroborating events that are not likely to be associated with adversarial activity. The various preselected events may include non-emergency situations such as a request to leave or disable made by two persons within the secure area, a request to leave or disable made by a single person within the secure area plus security guard affirmation, and a request to leave or disable made by a single person within the secure area plus the expiration of a time delay triggered by the request.

Abstract: A quick close circuit is provided for an electric powered gate having a wire loop control system comprising a gate control circuit, a wire loop in a passageway of the gate, and a loop detector circuit to sense presence of vehicles in the loop. The quick close circuit provides for the opening of the gate upon detection of a vehicle in the passageway by the loop detector circuit. After the vehicle has passed through the passageway, the quick close circuit stops further opening of the gate and commences the closing of the gate.

Abstract: A safety message announcing device is interconnected to a machine so as to make the machine inoperative until the safety message has been announced. A control signal is provided along with the safety message. A control mechanism interconnected to the start switch of the machine will only operate when the control signal is received. The control signal may take the form of multiple fixed frequency tones announced along with the message, with the control mechanism tuned to the tones to only enable the machine when the tones are heard by the control mechanism, thus assuring that the message has been announced as well. The control signal may take the form of a code that must be input by the operator before the machine will operate. This may be done with a visual as well as a sound annunciator.

Abstract: A fire door closure reset system including a fire door movable between an opened position and a closed position relative to an opening through a wall; a lock for being pivotally attached relative to the wall for movement between a locked position and an unlocked position and for allowing the fire door to move to the closed position when in the unlocked position; a spring for urging the lock to the unlocked position; a cable having a first end for being attached to the lock and having a second end for being fixedly attached relative to the wall; the lock being held in the locked position when the cable is taut; the spring urging the lock to the unlocked position when slack is placed in the cable; occurrence responsive structure for placing slack in the cable in the event of a predetermined occurrence; and a test-reset mechanism for allowing the operation of the fire door closure reset system to be tested by placing slack in the cable and for allowing the slack in the cable to be subsequently removed after the

Abstract: An automatic sliding door in which a main drive moves at least one door panel to open and closed positions. An electromagnetic clutch is located between the main drive and the door panel for the purpose of disconnecting the panel from the drive and to open the door in event of a power failure. An auxiliary drive is connected to the door panel and stores energy received when the door panel is in a closed position, so as to drive the door to the open position when the clutch disconnects the main drive from the door panel in event of power failure. The auxiliary drive has a rubber cable actuated always with the door so that the auxiliary drive can be tested with every movement of the door panel.

Abstract: A window system is proposed in which windows (41) which can be both locked and tilted mechanically are connected via microprocessors (43) to a monitoring center (49) which can display the locking and closure status of the individual windows (41) via visual display units (51, 57). The microprocessors (43) are located in the vicinity of the windows (41) and connected to the receiver (61) of a radio-controlled remote control unit by which the windows can be remotely controlled. The windows (41) can also be controlled via an operating unit (65) in the monitoring center (49). The remote control unit may involve either portable transmitters (63) or transmitters with a fixed location (67) which control the windows (41) via sensors (69) as a function of ambient air parameters, such as the relative air humidity, temperature or the CO.sub.2 content of the air in the room. The windows (41) have a locking drive integrated in the handle and a separate tilting drive.

Abstract: It is proposed that the utilization period of the awning be increased in connection with automatic or manual manual control means in that the awning is preferably incrementally retracted as a function of the magnitude of the wind velocity, as determined through measurement, with the wind velocity being determined in corresponding graduations, and, as a function thereof, in that the control unit for the awning drive motor moves the awning to intermediate awning positions which have priority over all other control influences. In addition to the limit switches, which are present anyway and which indicate the "fully retracted" or "fully extended" positions, a plurality of intermediate sensors, corresponding to the number of desired increments, are disposed to determine the intermediate positions, with the signals output by the intermediate sensors, which indicate the actual position of the awning being compared with wind-velocity-determined awning setpoint position signals.

Abstract: A high speed door assembly, comprising an actuator cylinder and piston rods, a pressure supply cylinder and fittings, an electrically detonated explosive bolt, a honeycomb structured door, a honeycomb structured decelerator, and a structural steel frame encasing the assembly to close over a 3 foot diameter opening within 50 milliseconds of actuation, to contain hazardous materials and vapors within a test fixture.

Abstract: Disclosed is a locking mechanism to retain and seal a blast door of an amition compartment against a compartment door frame after an explosion in the compartment. The mechanism has a linkage connected to a panel that is blown off the compartment by the explosion, whereby the panel actuates the mechanism. The linkage turns a cam a controlled amount so that the cam contacts the door in an optimal position for retaining and sealing the door.

Abstract: Both a motion detector and a presence detector receive doppler shifted reflected microwave radiation to detect the passage of a person or an animal in a field of view. The motion sensor is adapted to detect the passage of a person or an animal near a doorway and to actuate the doorway in response thereto, to permit the passage of the person or animal thereto. The presence detector detects "swaying motion" of a person or an animal in a field of view much closer to the location of the sensor as its gain is much lower than that of the motion detection channel. In addition the presence detector is activated only in the event the motion sensor is deactivated. The output signals from the motion sensor and presence sensor are gated through an OR gate and to a timer to activate the door opener.

Abstract: A revolving door, particularly for the protection of the access to a room, comprises a rotating shaft, a number of door wings spaced around it and mounted thereto and a pair of opposite panels bordering the door wings and defining a partly closed zone with a first and a second opening. Further a drive motor for the shaft and a control unit for the drive motor are provided. The revolving door is provided with a detection means for detecting a person authorized or unauthorized to access the room, and a first sensor for detecting an unauthorized person entering the zone through the first or the second opening respectively. The control unit turns off the drive motor in response to the first sensor. A second sensor is adapted to detect the presence of an unauthorized person outside said zone in or close to the first or second opening respectively, wherein the control unit turns off the drive motor in response to said second sensor.

Abstract: A rain-actuated control for covering systems makes it possible to obtain a device capable of automatically closing open coverings in the event of rain. The device must be simple and easy to mount in existing installations. The rain-actuated control comprises a sensor consisting of two electrodes (1,15) with an intermediate layer of glass (13) and air (29) which functions as a capacitor. When rain is deposited (30) on the glass, the dielectric constant of the glass is changed, and signals are generated, which cause the control system to close the covering system. Automobile windows and automobile bodies can be used advantageously as elements of the capacitor.

Abstract: A backup gate controller for a motorized gate detects the loss of power to the gate and causes the gate motor to open the gate in response to loss of power or by an external trigger thereafter. The backup gate controller may be inserted between an existing gate controller and gate motor to bypass the existing controller when power loss is detected. Alternatively, the backup gate controller may be directly connected to the existing gate controller to cause the existing controller to open the gate when power loss is detected. A combined gate controller/backup controller may also be provided. Upon opening the gate, the backup controller and/or the gate controller may prevent the gate from being closed. The backup controller is battery powered and preferably includes a battery charger.

Abstract: The invention comprises a method for operating a door hold-open device and a device for carrying out the method. A door hold-open device which unlatches a held door based upon the occurrence of an unlatch condition includes a door latching mechanism, a signal processing circuit having a power source. The method consists of the steps preventing the signal processing mechanism from consuming electrical current, upon occurrence of an unlatch condition, generating a unlatch condition signal and providing electrical current to the signal processing mechanism to power it, determining the continued existence of the unlatch condition signal with the signal processing mechanism and upon determination of the continued existence of the unlatch condition signal with the signal processing mechanism, transmitting an electrical unlatch signal to the door latching mechanism.

Abstract: An apparatus for controlling a power window capable of maintaining an energized state of the motor to move a window glass, detecting a locked-rotor current flowing through the motor when the window glass reaches a limit position, and de-energizing the motor to stop the movement of the window glass when the locked-rotor current becomes larger than a predetermined value. The period of time for energization of the motor is longer than a period of time from a moment at which the "ON" operation of the automatic mode switch is cancelled to a moment at which the window glass reaches the limit position. It is thereby possible to automatically de-energize the motor when the window glass reaches the limit position, even if the locked-rotor current does not become larger than the predetermined value at this time due to the influence of temperatures or other causes.

Abstract: A sliding door with two for example panels coupled with a belt-drive mechanism driven in turn by a motor. The panels are also connected to an auxiliary drive mechanism that is provided with energy by the panel as it slides into a closed position and that can move the panel when the clutch is deprived of current. At least one programming switch, a motion sensor, and a limit switch activate regular controls that move the panel automatically. Self-monitoring additional electronic controls constitute a door-safety module.The object is to monitor the opening of the door in response to a signal from the motion sensor and to allow self-testing of the function of the auxiliary drive mechanism and ensure inherent reliability of the door-opening monitoring process. A door-safety module is controlled in accordance with a program and has at least one motion sensor and one limit switch associated with it.

Abstract: A control system for a revolving door includes an ultrasonic sensor having multiple sensor heads. The door has a housing, and multiple moveable compartments formed by door wings attached to and radially extending from a rotatable axis. The sensors emit energy waves into the housing in bursts, then receive echoes from any objects, including people, in the chambers. The sensors are activated when the door is activated by an authorized user. A controller stores a binary "echo" or "no echo" signal in memory in response to an emitted energy wave. The memory is formed by multiple arrays, each array having a column associated with a particular sensor and used for storing echo signals from a particular ultrasonic burst. Each bit in a column represents incremental ranges of objects from the sensor head, and the controller stores the "echo" or "no echo" signal in an appropriate bit based on the elapsed time from the preceding burst.

Abstract: A door hold open device for use with fire doors connected to a door closer unit. The hold open device has a latching means that automatically unlatches if the power supply drops below a predetermined threshold or a person attempts to disconnect the power supply. The device includes an electrical actuating means for unlatching the held open door. The actuating means allows a door to be latched open without constant current being supplied to the actuating means, so battery power is possible. The invention may be used with any door closer unit, does not require special wiring, and may include a self-contained power supply and an integral smoke detector.

Abstract: A door hold open device for use with fire doors connected to a door closer unit. The hold open device has a latching means that automatically unlatches if the power supply drops below a predetermined threshold or a person attempts to disconnect the power supply. The device includes an electrical actuating means for unlatching the held open door. The actuating means allows a door to be latched open without constant current being supplied to the actuating means, so battery power is possible. The invention may be used with any door closer unit, does not require special wiring, and may include a self-contained power supply and an integral smoke detector.

Abstract: A redundant sensing edge for a door to protect persons, equipment and the door from impact damage by actuating a device upon detecting an object in proximity to the door edge. The sensing edge includes an elongate outer sheath compressible upon application of external pressure. A force sensing switch is positioned within the elongate outer sheath for sensing the application of force to the sheath. Upon force being applied to the sheath, the force sensing switch actuates the device for controlling the door. The sensing edge also includes a proximity sensing switch for detecting the presence of an animate object in proximity to the door edge. The proximity sensing switch includes an electrical circuit positioned near the elongate sheath and a control circuit for detecting changes in the capacitance of the electrical circuit. An animate object in proximity to the elongate sheath changes the capacitance of the electrical circuit.

Abstract: A control system for a revolving door includes an ultrasonic sensor having multiple sensor heads. The door has a housing, and multiple moveable compartments formed by door wings attached to and radially extending from a rotatable axis. The sensors emit energy waves into the housing in bursts, then receive echoes from any objects, including people, in the chambers. The sensors are activated when the door is activated by an authorized user. A controller stores a binary "echo" or "no echo" signal in memory in response to an emitted energy wave. The memory is formed by multiple arrays, each array having a column associated with a particular sensor and used for storing echo signals from a particular ultrasonic burst. Each bit in a column represents incremental ranges of objects from the sensors head, and the controller stores the "echo" or "no echo" signal in an appropriate bit based on the elaspsed time from the preceding burst.

Abstract: A garbage container is disclosed, which will open automatically when a user is present in front of the container and will close after a predetermined time of the departure of the user. This garbage container comprises an infrared ray transmitter and an infrared ray receiver to detect the presence of a user.

Abstract: A computer assisted transit car door operating system for augmented automation of transit car door panel operation while providing safety provisions to restrain rail movement unless all passage doorways are closed. A programmable logic controller generates a sequence initiating (opening or closing) signal for a door panel; or, a manual input signal can be introduced for such purpose. The controller receives signals from a panel position sensor and a panel movement sensor to evaluate door panel status and generate status indication and panel movement signals. Automated control of door panel movement is selectively directed to a doorway, or doorways, at which an opening or closing problem is being encountered; that is, the exclusion of door panel movement signals to properly operated door panels.

Abstract: A window security system including a door disposed over a window and moveable between a closed position and an open position. The door may be selectively locked in the closed position by an electrically actuated lock. The system further includes a smoke detector and an actuator for automatically unlocking the door when the smoke detector detects smoke. The system also includes manual override features for unlocking the door even when the smoke detector detects smoke and also for preventing the door from unlocking when the smoke detector detects smoke. The system may also include audible or visual signals for indicating whether the door is in the open position.

Abstract: A fire escape system is described in which a latched escape door in a building is unlatched by withdrawal of a restraining pin from a latch mechanism, producing automatic opening of the door by any of various door-opening self actuating means described. In one embodiment, withdrawal of the restraining means results as a consequence of the transmission of a signal generated by a fire detection device, to an electric windlass system, which thereupon retractably winds a cable attached to the pin, withdrawing it from the latch mechanism.

Abstract: A power drive system for opening and closing the sliding side door of a van type vehicle includes an inclination detector controlled control circuit for adjustably regulating the closing force applied to the door in approximate proportion to the inclination of the vehicle to provide sufficient power to close the door when the vehicle is parked on an uphill grade while providing a reduced amount of power to close the door when the vehicle is on level ground.

Abstract: A detector unit, for detecting fumes, including carbon monoxide, is located in a garage, and circuitry controlled thereby automatically opens the garage door, or operates an exhaust blower, or both. The door remains open, or the exhaust blower continues operating, or both, until the circuitry is manually reset.

Abstract: A transom member for a sliding door having an elongate support member and a cover member secured to the support member. The transom member has a cavity defined between the support member and cover member and sensing means for sensing approach of a person towards the transom member is housed in the cavity. The sensing means includes an energy detector for detecting energy from a person approaching the transom member, and the detector is positioned for receiving such energy through the cover member.

Abstract: A radio remote-controlled door operator for use, among other uses, as a residential garage door operator. The transmitter contains two buttons, one to produce normal door operation and the other to set the operator into a "secure" mode wherein it will be non-responsive to further valid operating codes until reset. In addition, a second deeper level of security may be established by means of a vacation switch which disconnects the operator from the AC power supply. The operator system comprises a microprocessor which is programmed to perform various accessory functions even through the accessories may not be present. Various microprocessor inputs are tied to a false "safe" level so that even though the accessory programs are run, no outputs result and no interference with normal door operation is produced.

Abstract: A device is described for the automatic closing of openings on a floating structure whereby the need for human or manual intervention is eliminated. Once the floating structure is subjected to tilting (heeling), lateral, or other accelerating forces, an unstable mass is used as a triggering device to remove a block from interfering with the path of the closure. The closure rolls down a ramp and covers an adjacent opening to seal it., thus preventing uncontrollable flooding or fire from spreading within the structure.

Abstract: A device is described for the automatic closing of openings on a floating structure whereby the need for human or manual intervention is eliminated. Once the floating structure is subjected to tilting (heeling), lateral, or other accelerating forces, an unstable mass is used as a triggering device to remove a block from interfering with the path of the closure. The closure rolls down a ramp and covers an adjacent opening to seal it, thus preventing uncontrolled flooding or fire from spreading within the structure.

Abstract: A signalling system utilized in a firedoor control system. For warning and alerting personnel of the immanate (seconds) closing of a firedoor, to avoid injury of such personnel in the vicinity of the closing firedoor. The system is actuated by being responsive to either a smoke detector signal or to an electrical failure to the smoke detector. Means responsive to the smoke detector generates a first control signal, a first timer means generates a second control signal at the end of a first delay interval, and a second timer means generates a series of reoccurring control pulses transmitted to audible and visual signalling elements. A test means is provided to determined operational (functional) status of a rechargable battery utilized in the system in the event of an electrical failure to the smoke detector.

Abstract: An electromagnetic door lock system employs an electromagnetic lock which magnetically bonds with an armature plate. An acoustical sensor generates a detection beam. The detection beam is directed toward the doorknob. Reflected energy is received and electronically processed to detect the presence of a foreign object in the vicinity of the doorknob. The lock automatically deactuates when a foreign object is detected in the vicinity of the knob. The electromagnetic lock, sensor and processing circuitry are mounted in a housing which is located near the top of a doorway. An audio alarm and status light indicators are mounted at the housing to indicate the status of the lock.

Abstract: An automatic door including a door body connected to a chain or belt extending between and wound around a drive pulley disposed on one side of a door opening and a driven pulley disposed on the other side thereof in which the door body is actuated to open and close by allowing the drive pulley to be rotated forwardly or reversely by an electric motor connected through a main switch and a controller to a main electric power supply source, comprises an apparatus for automatically moving the door body to its closing-stop point when the supply of electric power to the motor is interrupted by the OFF operation of the main switch, and a locking apparatus for automatically locking the door body in its closing-stop position at that time.

Abstract: A smoke detector-activated door seal includes an extensible member in the form of an inflatable bladder disposed about the periphery of the door. A source of compressed air is connected to the bladder such that, upon a door-carried smoke detector sensing the presence of smoke, the source of compressed air inflates the bladder so as to provide a substantially airtight seal between the door and the door frame. A manually actuated release valve is provided to enable the seal to be released whenever desired.

Abstract: An automatic door installation with two traffic sensors mounted on each side of the door adjacent the opposite side edges thereof, each having a reflected energy receiver and a plurality of radiant energy emitters with angularly spaced beam axes to provide broad coverage areas intersecting the traffic path of travel. The emitters of each sensor are selectively activated at different radiant energy levels and/or selectively deactivated to vary the affective coverage area as the door is swung between its closed and open positions.

Abstract: A controlling device for an automatic door which can detect a human body approaching the door assuredly in a relatively early stage and hence can assure smooth passage thereof by a person after another person has passed it. The controlling device comprises a controller, a first human body detecting sensor having a small detecting area near the door, and a second human body detecting sensor having a wider detecting area which extends remotely from the door and covers the detecting area of the first human body sensor. The controller develops a door opening signal in response to a human body detection signal received from the first human body detecting sensor when a door closing signal is not being developed from the controller whereas it develops a door opening signal in response to a human body detection signal from the second human body detecting sensor when a door closing signal is being developed from the controller.

Abstract: A window guard latch with emergency release comprising a bracket having a channel for receiving a portion of the window guard, a lock for engaging the portion of the window guard received in the channel, the lock having a trigger for releasing the engagement with the window guard, and a solenoid linked to the trigger to operate it. A control box, mounted inside the building has an RF signal detector and means to activate the solenoid in response to the detector to release the window guard. Smoke detectors which trigger an RF transmitter and portable push button RF transmitters can transmit an RF signal to remotely activate the release mechanism.

Abstract: A transit vehicle having a door includes a zero speed condition detection apparatus provided to logically supply a zero condition output signal for each of a plurality of axles when both of the tachometers for each of those axles are under a predetermined zero speed condition. When two or more zero condition output signals are so supplied, a failsafe driver is energized to operate a control relay for determining the operation of the door.

Abstract: An apparatus for holding a motor vehicle door in a desired opening degree thereof comprises a touch sensor provided on the door for detecting whether or not the touch sensor is touched by an operator, an engaging member pivotally mounted at one end thereof onto a vehicle body, a pair of piston-cylinder assemblies each including a friction member which is driven by pneumatic power to clamp the engaging member, and a control unit for receiving signals from the touch sensor and delivering commands to a power supply unit to drive the piston-cylinder assemblies upon receipt of the signal indicating that the touch sensor is touched by the operator.

Abstract: A signal light is projected in a concentrated beam downwardly when a garage door is fully opened to provide a light spot on the garage floor where no vehicle obstructs it and on the vehicle, such as on the dashboard thereof, when a vehicle is at a properly parked position in the garage. This provides signals both that the door is fully open, indicating that it is safe to exit or enter the garage as well as that the vehicle is in the proper position for parking. In addition, the light source itself may be arranged to glow visibly to an operator outside the garage as a further indication that it is safe to enter. Adjustable bracket means enables the location of the signaling lamp and signal-like spots to be adjusted. The light source is controlled by the position of the garage door, so as to only be illuminated when the door is fully opened.

Abstract: A building has at least one security guard post to control the secured building exits, each of which has an unlocking instrumentality, without forbidding their emergency use. When activating the unlocking instrument to open a secured exit, there is a transmission of information to the security guard post and an initiation of a delay during which the security guard can forbid the opening of the exit. The unlocking instrument can also visually indicate events at the exit. The apparatus has an electro-mechanical lock, a sensor which is sensitive to motion of the unlocking instrument, a control line linking each door to be controlled to the security guard post, and a central electronic processing unit. A surveillance circuit responds to the sensor. A security circuit frees the unlocking instrument when a fault is detected.

Abstract: A revolving door and controls therefor are set forth to restrict access into a room to only authorized personnel. The revolving door is disposed in a housing having an entrance and an exit into the room. The revolving door includes a plurality of wings which, in cooperation with the housing, define a plurality of compartments movable in response to rotation of the door to transport a person between the entrance and exit through the housing. Included are means for identifying authorized personnel and driving the door for rotation to transport that authorized person in a selected compartment between the entrance and the exit. Means are included for sensing two or more persons in the selected compartment moving from a starting point between the entrance and the exit, the sensing means reversely rotating the door to return the selected compartment to the starting point.

Abstract: An automatic mat-activated operating system for swinging doors provides approach circuitry for opening the doors when an approach mat at the entrance side of the doorway is activated and override safety circuitry for stopping door opening movement and returning the doors to a closed position when a safety mat at the exit side of the doorway is activated within a predetermined initial range of door movement but not thereafter and also for preventing door opening movement if the safety mat is already activated at the time of initial activation of the approach mat. The control system thus protects pedestrians at the exit side of the doorway from being struck by the doors during their initial opening movement which may not be readily recognizable and avoidable and also protects pedestrians entering the doorway from the entrance side from being struck by unexpected return movement of the doors.

Abstract: The system automatically warns when opening of an exit door is attempted, causing an alarm to be made and preventing full opening for a predetermined period of time. Such a system includes an electromagnet, timer, alarm and activator switch connected in series with a power source such as house current and disposed in and around the frame with no electrical connection to or from the door. A magnetically attractable plate or prong is secured to the door adjacent to the electromagnet. The switch may include a spring biased plunger on the frame, held in the closed circuit position against the spring bias with the door closed. The switch automatically moves to the closed circuit position when the door begins to open, causing an alarm to be immediately sounded and the plate to continue to be strongly held by the electromagnet, thereby preventing full opening of the door. The system permits the full opening of the exit door only after a suitable period of time has elapsed.

Abstract: A solid state integrated regulating circuitry for incorporation in the conventional control circuitry of automatic sliding door systems includes timing and processing circuits operative through plural inverters to deliver enabling and disenabling electrical signals to the control circuitry when the elapsed time between cycles of door opening and closing actuations are greater or less than a predetermined time respectively either to prematurely terminate or to have no altering effect upon door opening actuation, thereby to open the doors to a reduced width during low traffic conditions and to open the doors to a full width during high traffic conditions.

Abstract: In an apparatus for closing a fireproof door in case of emergency, the fireproof door and a release, which is secured to a door frame, are interconnected by a link mechanism comprising first, second and supplemental link arms. One end of the first link arms is pivoted to a driving shaft of a door closer secured to the fireproof door. The other end of the first link arm is pivoted to one end of the second link arm, the other end of which is pivoted to the release. The supplemental link arm is connected between the central point of the second link arm and a slider which is slidably mounted inside the release and latched by a latch mechanism when the fireproof door is open.When the slider is released from the latch mechanism by electrizing a solenoid which operates the latch mechanism, the slider is slid inside the release by the closing force of the door closer transmitted via the link mechanism, thereby closing the fireproof door.

Abstract: Damper for the protection of equipment, through which a gaseous or vaporous medium, particularly air, flows, against pressure waves, particularly in ventilation and/or air conditioning installations for the protection of the components of the plant, its internals and ducts, consisting of a frame structure and a multiplicity of slats (15) which are supported therein hinged about parallel axes and in one plane and which are held in their open position by restoring forces and are braced against stops.

Abstract: A revolving door and controls therefor are set forth to restrict access into a room to only authorized personnel. The revolving door is disposed in a housing having an entrance and an exit into the room. The revolving door includes a plurality of wings which, in cooperation with the housing, define a plurality of compartments movable in response to rotation of the door to transport a person between the entrance and exit through the housing. Included are means for identifying authorized personnel and driving the door for rotation to transport that authorized person in a selected compartment between the entrance and the exit. Means are included for sensing two or more persons in the selected compartment moving from a starting point between the entrance and the exit, the sensing means reversely rotating the door to return the selected compartment to the starting point.