Abstract: A garage door opener is retrofitted with a device that causes a garage door to close after it has been open for a predetermined amount of time. In a garage door of the type having a light that is activated when the door is opened or closed, a photocell is mounted in close proximity to the light to detect the presence or absence of light. When light is detected, the photocell conducts and prevents a first automatic switch, such as a silicon-controlled rectifier, from conducting. When absence of light is detected, the first automatic switch closes and a capacitor discharges through the first automatic switch and throws a second automatic switch, such as a transistor, that is electrically connected in parallel to a manually-operated switch for opening and closing the garage door. When the second automatic switch conducts, it mimics closing of the manually-operated switch and thus effects closing of the garage door.

Abstract: A new automatic bathroom door and toilet flushing system for automatically raising the door and flushing the toilet when a user is finished. The system includes a housing secured to a ceiling between a pair of walls. The housing has an opening in a lower end thereof. A door is rotatably disposed within the housing. The door is disposed on a central shaft. The central shaft is coupled with an electric motor. The electric motor selectively raises and lowers the door with respect to an opening between the pair of walls. An electric sensor is in communication with the electric motor and an electrical system of an existing toilet. The electric sensor is disposed within one of the pair of walls adjacent to the handle of the manual pulley system.

Abstract: A door panel is actuated when an actuator sensor disposed near the door panel senses an object approaching the door panel. When a safety sensor mounted on the door panel senses an object while the door panel is opening, the door panel is stopped. When a safety sensor mounted on the door panel senses an object while the door panel is closing, the door panel is opened. Each of the sensors includes a light-emitting unit, a light-receiving unit and a control unit, and the sensor can detect for itself failure in any of the light-emitting unit, the light-receiving unit and the control unit.

Abstract: The garage door position indicator contains a radio frequency (RF) transmitter with an electronic angle sensor attached onto a garage door, and a RF receiver with a visual/audio indicator. The electronic angle sensor supplies signals to the RF transmitter during the changes in orientation of a garage door from vertical to horizontal and from horizontal to vertical. The RF receiver is responsive to the RF signals from the RF transmitter and controls a visual/audio indicator to indicate the position of a garage door accordingly.

Abstract: A new Air Window Apparatus for providing an intrusion-proof vehicle ventilation system. The inventive device includes an essentially rigid member having a plurality of ventilation holes extending therethrough.

Abstract: A receptacle comprising a body including an opening having a door hingedly mounted therein for movement between a normal and substantially vertical orientation and a substantially horizontal orientation, a drive assembly having a hub for taking up and letting out the cord for moving the door between the substantially vertical orientation and the substantially horizontal orientation, and an actuator device for actuating the drive assembly, the hub being spaced apart from said hinge proximate an optimum position for minimizing the amount of force necessary for the drive assembly to move the door.

Abstract: An add-on control device is shown that is used in conjunction with existing garage door opener systems. The device includes an electronic control device that will automatically close the door if left open, or can be programmed to stay open, and will automatically close an open door when it gets dark. The device includes a control circuit, connected in parallel with the push button control of the garage door opener, actuated when the garage door is opened. A timing circuit having at least two selectable timing cycles is actuated when the garage door is opened and closes the garage door after a selected timing cycle. A cancel circuit cancels the selected timing cycle when the garage door is to remain open. A reset circuit, called the cancel switch is used for re-initiating the selected timing cycle to close the garage door.

Abstract: A novel apparatus and method for a washing machine wherein which the door may be automatically opened and closed. The door opening/closing apparatus comprises: a sensor for determining an opened state of the door; a sensor for determining a closed state of the door; a motor for supplying a dynamic force to open and close the door; an external input mechanism for entering a door opening/closing command; and a controller for determining the state of the door based on information supplied from each of the sensors when a door opening/closing command is present, and controlling the activation of the motor, accordingly.

Abstract: For a vertical slide type front window of an operator's cab of construction machines, a windshield wiper assembly is mounted on a panel alongside the front window. Mounted on the part of the front window is a pin-latch unit for fixing the front window in a fully closed position. When a slide pin of the pin-latch unit is applied to lock the front window, this is detected by a detection means of a windshield control to render the wiper operative.

Abstract: A pinch seal in which particle generation by frictional contact is prevented so that the pinch seal can be used in a semiconductor processing apparatus where elimination of particulate contamination is desirable. The pinch seal is particularly adapted for use in connection with a semiconductor wafer transport device, such as a linear transport device. The pinch seal is formed in a barrier provided between a transport device and a semiconductor processing work environment. One or more support members for transporting a wafer extend through the pinch seal. In one embodiment, the pinch seal includes a flexible sealing member with a magnetic strip extending along the length of the flexible sealing member.

Abstract: A movable section of a machine is enclosed by a fence and a door. A locking device provided on the door is controlled by a movable section control circuit. In the movable section control circuit, an operating switch outputs either a movable section ON signal or a movable section OFF signal. A door switch outputs an ON signal representing that the door is open. A switch means constitutes a self-holding circuit which uses an AND signal constituted of the movable section OFF signal from the operating switch and a rotation stop signal as a reset input signal and an OR signal constituted of an ON signal from the door switch and a rotation-presence signal as trigger signal to provide the locking device with a control signal. When a sensor fails, the locking devive is not unlocked even if the operating switch for driving the movable section is closed.

Abstract: A safety system for a stable comprises "smart detectors" installed in the stable for detecting at least one abnormal condition in the stable, a siren and/or flashing strobe installed in each stall for spooking horses out of their stalls, an electro-magnetic lock provided on each said door, a power source supplying power to each said electro-magnetic lock keeping each door closed in the absence of the abnormal condition, and a controlling means continually monitoring said "smart detectors". Once the abnormal condition has been detected, the controlling unit immediately turns down the power supplied to each electro-magnetic lock and, with a certain delay, actuates the siren and/or flashing strobe.

Abstract: An electromechanically operated door having a control and regulation system for the door, the door for being driven by an electric motor, the movement of the door being controlled by sensors. The control and regulation system is equipped with a microprocessor control. In addition to the normal path of data to the microprocessor control, a dual redundancy is achieved, in that there is a safety monitoring system which receives the same safety-related information as the microprocessor control. This safety monitoring system, for its part, is capable of detecting a fault, i.e. if the microprocessor control system has not shut off the door, the door is shut off by the safety monitoring system, which for its part reports any faults which occur in the system to a fault detection unit, and here again, by means of a redundant shutdown unit, brings the connected motor and thus the door to an immediate stop.

Abstract: A programmable automatic window including a hollow frame with an aperture disposed therethrough; a window slidably secured within the aperture of the frame; a ball screw mechanism disposed within the frame and coupled to the window; a motor coupled to the ball screw mechanism and energizable with a positive polarity to cause rotation of the ball screw mechanism for allowing the window to be raised and energizable with a negative polarity to cause opposite rotation of the ball screw mechanism for allowing the window to be lowered; and motor logic switch circuitry for controlling the motor.

Abstract: This invention describes a monitoring device which monitors the safety of a printing machine. The printing machine has a drive, a control unit arranged upstream of the drive, command buttons which are connected to the control unit and via which the start-up of the printing machine can be initiated, as well as sound generators, connected to the control unit, for the emission of an acoustic alarm signal after the actuation of one of the command buttons initiating the start-up. The monitoring device ensures that a start-up of the printing machine is only carried out if an acoustic alarm signal has previously been properly emitted. This is achieved, according to the invention, by the monitoring device registering the emission of the acoustic alarm signal and, in the event of the alarm signal not being emitted, inhibits the drive of the printing machine from starting up.

Abstract: A visual display panel is mounted on the exterior surface of a power-operated garage door to display messages for viewing by occupants of a departing automobile after the garage door has closed. The display panel may be part of an integrated home automation system (IHAS) so that, in addition to pre-programmed messages, the operational status of household devices included in the IHAS are presented on the display panel. Actuation of the garage door operator to open the garage door can also cause the IHAS to direct changes in the operation of one or more of the included devices.

Abstract: Horizontally hinged covers for use in ceiling/floors are provided which are highly fire resistant and which in the event of fire automatically close. The door preferably utilizes a multi-layer construction comprising an intumescent lower (inner) layer, an intermediate structural layer and a top (outer) layer of a cementitious material. The horizontally hinged door utilizes an automatic closing system in the event of fire comprising a fusible link which activates a pressurized gas source to close the door and which pressurized gas source is automatically purged when the door is closed to prevent explosion of the pressurized gas source. The fusible link also actuates (opens) a hydraulic valve to allow the flow of hydraulic fluid from a pneumatic/hydraulic housing which is used with a movable rod to open and close the door.

Abstract: The present invention provides a security system for controlling access of persons through a controlled portal. The portal, such as a door, has a lock mechanism for securing the door. A presence detector senses the presence of an object within an approach zone located substantially adjacent the portal. When an object is detected, a fixed transceiver automatically transmits an interrogation signal into the approach zone. A portable transceiver is carried by the person seeking access to the portal. The portable transceiver responds to the interrogation signal by transmitting a response signal. Each portable transceiver or group of transceivers has a unique identification code which is included in the response signal. The fixed transceiver receives the response signal and determines whether the response signal contains a valid access code. If a valid access code is received, the portal is unlocked and other devices may be activated.

Abstract: Apparatus for actuating a safety device comprises an acoustic sensor and apparatus coupled to the sensor for actuating the safety device in response to sound of a predetermined character. Apparatus for releasing or closing a closure is also disclosed. Three embodiments of the apparatus are disclosed.

Abstract: A life saving system that allows escape from secured premises is provided. The system includes door/window locks that are normally held in the locked position by the presence of an electrical current through solenoids contained in the locks. When an accessory fire/smoke alarm is activated, current through the solenoids is interrupted, thereby automatically unlocking the doors or windows. Uninterruptable power supplies are provided that can operate from alternating current or direct current sources. Additional security is provided by an optional key lock shunt box that prevents tampering by unauthorized users.

Abstract: A microwave oven having a cavity and a door for closing off the cavity. The oven is fitted with a pressure actuated safety catch device which prevents opening of the door as a consequence of a sudden pressure increase in the cavity. The sudden pressure increase in the cavity is used to activate the safety catch device which catches the locking device of the door.

Abstract: A system for preventing the automatic or inadvertent opening of an aircraft door or access hatch that has not been closed and locked properly provides an increase in the overall flight safety of aircraft. The system includes a door monitoring system (1), which is connected to at least one of a cabin pressure control arrangement (4), a cabin temperature control arrangement (5), and an air tap system control arrangement (36). The door monitoring system (1) provides a signal indicating if at least one door or access hatch is not properly closed and locked. The controllers (4, 5, 36) receive the door monitor signal at respective inputs and also receive information necessary for determining the current flight configuration of the aircraft from various other aircraft systems, such as a landing gear control arrangement or an engine monitor arrangement.

Abstract: A microprocessor-based door control unit includes a programmable, non-volatile-memory for storing door operating parameter values. A separate programming unit, arranged for connection to the door control unit, includes a second microprocessor, a keyboard and a display. The parameter values stored in the non-volatile memory can be read by the programming unit, and new values can be stored in the non-volatile memory using the programming unit.

Abstract: An automated actuator is fabricated in kit form and adapted to be assembled and disassembled for use with sliding doors, windows or other similar panels. The actuator includes a support column which is adjustable to be braced at the existing door jamb at either side of the door frame to move the panel. Mounting of the actuator does not require the surrounding frame or wall structure to be structurally altered. Circuitry for the actuator ceases the sliding movement of the door when the door meets resistance, such as by a child or animal in the path of the door, and re-tests for the resistance to determine whether the door should continue along the intended path.

Abstract: A pressure relief panel assembly for protecting a building against over-pressure caused by explosion. The assembly has a panel pivotally connected to a frame and held by a calibrated magnet and striker set which releases when a predetermined over-pressure occurs. A cable restraint attached to a shock absorber, or a linkage of two arms attached to a shock absorber, limits the extent to which the panel can blow open. A spring mounted on one of the arms catches the other arm when the panel has blown open, preventing the panels from reclosing and thereby preventing implosion damage to the building. Alternatively, or additionally, the panel, after opening, may be held partly open by a stop bar which pivots to prevent the panel from fully closing, to prevent implosion damage to the building after the explosion.

Abstract: Fire door for an elevator, especially for use in the landing doorways of an elevator shaft. The fire door is mounted abreast of an elevator landing door. The fire protection characteristics of the fire door are so chosen that the elevator door and the fire door together fulfil the requirements imposed on a fire door.

Abstract: A garage door position indicating system includes a tilt switch attached to a garage door, an RF transmitter coupled to the tilt switch, an RF receiver, and an indicator controlled by the RF receiver. The tilt switch supplies an enable signal to the RF transmitter at selected first tilt positions and blocks the enable signal at selected second tilt positions. The RF transmitter generates an RF signal in response to the enable signal. The RF receiver is responsive to the RF signal and controls an indicator to indicate the position of the garage door.

Abstract: A security system operates in response to an attempted egress through a door by a preselected person. The magnetic field of a permanent magnet is passed in a preselected spatial relation which respected a current generating device to generate a current upon the attempted egress through the door by the preselected person carrying the permanent magnet, and a security device is energized to lock the door upon the establishment of the generated current. A method of operating a security system is also disclosed.

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.