Abstract: An airflow damper Is provided, the airflow damper includes a resilient body having a fixed end and a free end. In a default state, the free end extends to restrict airflow. In a device accommodation state, the free end flattens to accommodate a device.

Abstract: The present invention relates to a dual zone type air conditioner for vehicles, which includes two air volume controlling doors mounted on an air inflow port of an air-conditioning case where the cross section of an air passageway is uniform and a flow of air is relatively uniform, a sealing wall mounted between the air volume controlling doors, and a controlling part mounted for selecting a more air volume side as a level of a blower when an air volume set by a driver and an air volume set by a passenger are different from each other and controlling the air volume controlling doors to supply the set air volumes to a driver's seat side and a passenger's seat side.

Abstract: An air cleaner, which includes a casing having an enclosed air passage with a ventilation pipe for guiding in outdoor air, a windpipe affixed to one side of the casing for circulation of indoor air, a damper pivotally mounted in between the casing and the windpipe for controlling the passage the casing and the windpipe and flowing direction of air between the casing and the windpipe, and an air filter and a negative ion generator mounted in the windpipe for cleaning air passing through the windpipe.

Abstract: Potentially harmful particulate materials introduced into an airflow drawn into a structure's HVAC system are sensed by sensors provided on an intake fan and protective measures are taken in response to such sensed presence.

Abstract: A multifunctional ventilating fan comprises a machine body, a panel provided with an air inlet and an air outlet. The machine body includes a first area, a second area, and a third area separated by several partition plates. The first area is provided with a first heat exchanger and a ventilating blower. A exhaust port of the ventilating blower is communicated with the outdoor. The second area is provided with a second heat exchanger and a circulating blower. The third area is provided with a compressor. The air inlet of the panel is communicated with the first area to form a first air path. The air inlet of the panel, the first area, the second area and the air outlet of the panel are communicated in turn to form a second air path. A first valve is provided in the second air path for isolating the first area so that a third air path is formed by the air inlet of the panel, the second area and the air outlet of the panel communicated in turn.

Abstract: A room ventilating and air conditioning system has at least one flow duct for a medium flowing therein and at least two air-related components. One component has a receiver and one component has a transmitter and the two components are connected via a wire-free connection, in particular a radio connection. At least one of the transmitters should project, at least with a subregion, to such an extent into the interior of the flow duct that the waves emitted by this transmitter are conducted substantially through the flow duct and/or at least one of the receivers should project, at least with a subregion, to such an extent into the interior of the flow duct that it is able to receive the waves conducted substantially through the flow duct.

Abstract: A canopy for a biological cabinet includes a plurality of openings, referred to as ports, covered by air dampers and designed to open and close as needed to reduce an overall volume of air required during normal operation. If the building exhaust system attempts to pull more air than is supplied by the cabinet, the intake dampers will open to allow room air in through the intake ports, thus helping the cabinet to maintain an acceptable level of intake airflow at its front access opening. If the building exhaust system does not pull a sufficient amount of air, the outlet damper will open and let the cabinet exhaust air escape through the outlet port, thus enabling the cabinet to maintain an acceptable level of intake airflow at its front access opening. The canopy may also include an internal air baffle that helps to capture the cabinet exhaust air and direct it out through the opening connected to the building exhaust duct.

Abstract: A device for altering the airflow pattern from a ceiling vent diffuser. The device comprises a flexible member that is secured to a diffuser vane by a spring-biased hook and one or more tabs. A release button on the outer surface of the device is depressed to pivot the hook out of engagement with the vane. The device is complementary shaped to a region of the diffuser. When installed, the device blocks the openings in that region and substantially prevents air from flowing out of the openings. One or more devices may be installed in selected regions to block airflow from those selected regions. A plurality of devices may be utilized to completely prevent airflow from the diffuser.

Abstract: A system and methods providing real-time monitoring, management and control of a variable frequency drive retrofit to a constant volume air handling unit without making significant mechanical or control system changes. Customers and vendors are provided with a more informative and economically attractive air handling unit. The system also provides a finer granularity of control over conditioned air properties such as temperature, humidity and air quality.

Abstract: A system for ventilating an area surrounding a patient is disclosed. The system includes an air exchanger configured to induce an air flow, and an outer duct disposed in communication with the air exchanger, and having an airway aperture configured to selectively induce an air flow at a location along the outer duct. The system further includes an inner duct disposed in communication with the air exchanger and disposed inside the duct, the inner duct being configured to selectively induce an air flow at a location along the inner duct. A method of ventilating an area surrounding a patient is also disclosed.

Abstract: An HVAC unit ventilator, particularly suited for schools and hotels, includes a single damper blade driven directly by a motor to control a supply air's mixture of return air and outside air. The damper blade is selectively pivotal to a full outside air position, a full return air position, and various intermediate mixed-air positions. The damper blade has flexible edge and end seals that create little if any frictional drag as the damper blade pivots to the intermediate positions, yet the seals provide a positive, tight seal when the damper stops at either the full outside air position or the full return air position. The unit ventilator includes a filter frame that not only supports an air filter but also provides the damper blade with sealing surfaces and structural support. For rigidity, the damper blade has somewhat of a box-like structure that is bi-directionally reinforced by ribs and triangular gussets.

Abstract: The invention relates to a method and mechanism to control air flow through an air handling system. In one aspect, a flow control device for use in an air handling system is provided. The device includes a flow control member having segmented sliding gates, wherein the flow control member is configured to selectively control an air flow stream by moving the sliding gates into the path of the air flow stream. The device further includes a controller member configured to control the movement of the sliding gates. Furthermore, the device includes a communication member configured to send and receive signals regarding the control of the air flow stream. Additionally, the device includes a power member for supplying power to the flow control member, the controller member and the communication member. In another aspect, a method of controlling an air flow stream in an air handling system is provided.

Abstract: An air flap device (10) for a cooling or/and freezing appliance of kitchen equipment comprises an air flap (18) which is mounted so that it can pivot about a first axis of rotation (20) between an open position and a closed position, uncovers an air passage opening for the passage of air in the open position and at least substantially blocks the air passage opening against the passage of air in the closed position, and a motor-driven flap operating mechanism for pivoting the air flap. According to the invention, the flap operating mechanism comprises a rotary member (26) which is disposed so as to be driven about a second axis of rotation (28) as well as a separate force transmission member (32) which serves to transmit force between the rotary member and the air flap, is coupled to the rotary member at a point lying eccentrically to the second axis of rotation and is coupled to the air flap (18) at a point lying at a distance from the first axis of rotation.

Abstract: A SDHV damper assembly and methods to assemble and install the SDHV damper assembly are disclosed. The SDHV damper assembly includes a first damper housing half comprising a substantially cylindrical tube having a first open end and a second open end. The SDHV damper assembly further includes a second damper housing half comprising a substantially cylindrical tube having a first open end and a second open end. The first open end of the second damper housing half is joined to the first open end of the first damper housing half to form an assembled damper housing. A recess is formed in the damper housing either diametrically or longitudinally. The expandable damper member is received within the recess and expands to restrict flow in the damper housing and retracts to allow laminar flow through the damper housing.

Abstract: The invention involves an air distributing apparatus for installation in a diffuser. The apparatus includes a first damper positioned within the diffuser. The first damper also has an open mode where a stream of air can exit the diffuser to a space. The first damper has a closed mode where the damper inhibits the stream of air from exiting the diffuser. The apparatus includes an actuator operatively connected to the first damper. There is an occupancy sensor positioned and configured to distinguish whether the space is occupied or unoccupied by a person. The occupancy sensor is in communication with the actuator. When the space is occupied by the person, the occupancy sensor communicates with the actuator to thereby cause the first damper to be positioned in the open mode. When the space is unoccupied, the occupancy sensor communicates with the actuator to thereby cause the first damper to be positioned in the closed mode.

Abstract: A system for controlling airflow in a plenum, that comprises a worm gear and planetary gear that are removably coupled to a worm shaft and planetary shaft, respectively. The planetary shaft controls the movement of a damper between an open position permitting maximum airflow through the plenum, and a closed position restricting airflow through the plenum. A motor or gear-motor is positioned at the plenum for driving the worm shaft. The motor is controlled by a remotely located controller that includes a power supply for operating the motor and that has a display providing a continuous indication of the position of the damper between the open and closed positions. The controller is connected to the motor through a cable with a detachable electrical connection between the cable and the controller, such as a jack and plug. A wall plate for housing the electrical connection is mounted on a wall or other structure.

Abstract: An air handling unit having multiple fans includes a damper assembly to limit recirculation of air past a non-operating fan. The damper assembly includes a panel adjustably positioned between two channels to allow the discharge of the multiple fans to be substantially opened or to be substantially closed.

Abstract: The present invention provides an air flow control device that includes at least one inlet, and a primary flow path associated with a primary outlet, and a secondary flow path associated with a secondary outlet. The air flow device also includes at least one primary valve associated with the primary flow path, said at least one primary valve being adapted to control the flow rate of air through said primary flow path.

Abstract: The present invention relates to a multi-valve damper which divides a section of an airflow duct into at least two airflow sections. The damper has a plug body having a proximal end and a distal end. The plug body is adapted to separate a section of an airflow duct into at least two airflow sections. At least two damper blades may be mounted on the distal end of the plug body, each of the damper blades controlling airflow in a respective airflow section. At least one airflow sensor may be provided in each of the airflow sections for controlling the respective damper blades. An actuator mechanism responsive to the sensors may be provided for opening and closing the damper blades. At least one of the proximal end and the distal end of the plug body may have an aerodynamic shape.

Abstract: An insect/dust-proof air shutter which can positively prevent intrusion of foreign mater such as insects and dust and further trap intruded insects is provided.

Abstract: A damper assembly, comprising an adjustable locking means for releasable retention of an element pivotally in one of a plurality of predetermined lock positions for adjusting air flow through an opening.

Abstract: A system for controlling airflow in a plenum, that comprises a worm gear and planetary gear that are removably coupled to a worm shaft and planetary shaft, respectively. The planetary shaft controls the movement of a damper between an open position permitting maximum airflow through the plenum, and a closed position restricting airflow through the plenum. A motor or gear-motor is positioned at the plenum for driving the worm shaft. The motor is controlled by a remotely located controller that includes a power supply for operating the motor and that has a display providing a continuous indication of the position of the damper between the open and closed positions. The controller is connected to the motor through a cable with a detachable electrical connection between the cable and the controller. Alternatively, the movement of the damper is controlled by a drive shaft, which connects the motor or gear motor directly to the damper without intervening gearing.

Abstract: A device is described for controlling the airflow through an airduct, the airduct having a housing, an inlet and an outlet. The device comprises a self-regulating valve having a diaphragm, the position of the diaphragm being determined by the difference between the pressure at the inlet and the pressure at the outlet. The diaphragm is rotatably suspended on a support so that, under influence of an increasing difference in pressure, the diaphragm can rotate between a minimum rotation angle and a maximum rotation angle over an intermediate rotation angle, the intermediate angle being situated between the minimum and maximum angle. The diaphragm is provided with a counterbalance and that, within the angle range between the intermediate rotation angle and the maximum rotation angle, the rotation movement of the diaphragm under influence of an increasing pressure difference is counteracted by an elastic resisting force.

Abstract: An air conditioning apparatus includes a casing and a dividing cosmetic panel. The casing has a suction port and a discharge port. The dividing cosmetic panel has a plurality of dividing panels and an opening/closing moveable mechanism for varying the positions of the dividing panels relative to the suction port. The opening/closing moveable mechanism switches between a state in which the dividing panels are disposed in proximity to each other, thereby blocking air flow through the suction port, and a state in which the dividing panels are separated from each other to allow ventilation through the suction port.

Abstract: A damper device for use with an air duct provides a paddle positioned within the duct and an axle extending distally from, and in a common plane with, the paddle through the duct wall, to a position for manual adjustment of the paddle within the duct. A bushing is tightened against the wall of the duct by a threaded knob and frictionally holds the axle in place using a combination of axially oriented fingers and O-rings. A handle is engaged with the end of the axle, enabling manual adjustment of the angular position of the paddle from outside the duct. The handle is in fixed alignment with the orientation of the paddle's peripheral edge, allowing for identification of the approximate angular position of the paddle from outside the duct, even when the duct is covered with a layer of insulation.

Abstract: A VAV box includes a housing formed by a top wall, a bottom wall, and a pair of vertical side walls. A blade is mounted for rotation about a vertical axis within an air flow passageway defined by a hollow interior of the housing. A first protuberance formed on an interior side of the first side wall has a leading wall swept back relative to an entrance to the box, a trailing wall swept forward relative to the entrance, and a concave wall that interconnects the innermost ends of the leading and trailing walls. A second protuberance having the same structure is formed on an interior side of the second side wall. The protuberances produce a linear response in air flow to changes in blade position, eliminating the non-linear response of prior art VAV boxes.

Abstract: A “quick change” restrictor assembly that allows quick rebalancing of flow-pressures within a duct system. The invention comprises a removable restrictor plate, a branch circuit for receiving the plate, and a means for retaining the restrictor plate to the branch circuit. The circuit includes a feature that allows for removal and installation of the restrictor plate without removing the branch circuit, inlet or outlet ducting. The quick change restrictor will not require bonding and can be installed easily from outside the duct without any disassembly. The restrictor may also have various clips or tabs to reinforce the slot the restrictor plate is inserted into. The restrictor may also have a smart part number and color code that is visible from outside the duct allowing easy removal, identification and inspection.

Abstract: The invention is a damper that closes off supply duct air when the unit is off to prevent air from exiting through the outlet, and opens when the unit is on to allow room air and/or supply duct air to exit through an outlet. The damper may be either motorized or mechanically biased.

Abstract: A method and apparatus for maintaining an acceptable level of outside air exchange rate in a structure. The natural ventilation rate is determined as a function of the outdoor air temperature, and the amount of mechanically induced ventilation that is used to supplement the natural air ventilation is controlled such that the sum of the natural occurring ventilation and the mechanically induced ventilation is maintained by a substantially constant predetermined level. One approach is to use a stepper motor to modulate the position of the damper, while another approach is to use an on/off motor damper and to close the damper at outdoor temperatures below a threshold level and to otherwise leave the damper open and use the regular on/off cycle of the system blower to control the flow of outdoor air, with provision for allowing the fan to remain on for a calculated period of time after the system is cycled off to thereby maintain the desired level of ventilation.

Abstract: Supervisory controllers, and methods, for use in a coordinated IAQ and economizer system. Various control objectives are defined and met. Some illustrative control objectives include economizer control, sequencing of economizer free cooling with compressor driven cooling, indoor air quality and FAV aims, demand ventilation settings, system protection from low temperatures, and smoke, supervisory and fault tolerance commands. The controller may be self configuring. A tiered fault tolerant controller is also provided. An illustrative controller is configured to determine whether various system sensors and devices are operational. The illustrative controller is also configured to perform a first method when all system sensors and/or devices are functioning, and at least a second method in response to sensor or device failures. The supervisory controller may include integrated economizer control, or may be configured as a separate controller.

Abstract: Apparatus for controlling the delivery of air in a forced air distribution system having a source of air under pressure (4), a duct system to deliver the air, and a plurality of ports (8) in the duct system with each port defining an air delivery zone (16). The apparatus includes a vent member (20) associated with each of the ports which is movable between an open position to admit air to the zone and a closed position to block air from the zone. Independent actuator units (50) are provided to move the vent member between the open and closed positions controlled by a central control system. Thermostats in each air delivery zone communicate with the central control system (80) to control operation of the actuators units and the source of air under pressure which generally comprises heating or cooling equipment such as a furnace or air conditioning unit.

Abstract: A complete plastic HVAC system assembled using individual plastic components for ensuring the efficient and quiet distribution of air from a central air unit to multiple distribution points and preventing heating and cooling losses, the need for installers to stock multiple sized and shaped components, the accumulation of dust, dirt and pollens during storing, installing and use on the surfaces of the individual components. The fittings have a collar sizable to fit both 6 and 7-inch pipe, whether flexible or rigid. The use of plastic fittings, duct and pipe removes the potential of injury commonly associated with conventional metal ductwork, while providing seamless components that can be configured for any type of installation and insure an air tight connection between adjoining surfaces. The individual fittings include a register boot, torpedo boot, straight boot, rigid and flexible pipe and couplers, straight and 90-degree takeoffs, a plastic duct and duct end cap.

Abstract: A ventilation system for providing fresh outdoor directly to each floor through an intake damper on the floor and for admitting only as much air as is required to meet the required outdoor air requirements when the temperature of the outdoor is at extreme ambient temperatures. The system utilizes a compartment unit on each floor and a plurality of VAV's which are located in zones on the floor for achieving desired temperatures in each zone by combining the recirculating air with the outdoor fresh air for delivering to the VAV's at about 55° F.

Abstract: A low-power, wireless, inflatable bladder damper device for controlling the flow of air through an airflow channel, and a method of operation for the same. Rather than requiring power supply and/or control wiring for operation of a wireless damper device, a low-power inflatable bladder damper device that requires no external wiring for operation can be used. A completely wireless damper device can reduce the cost of installation of damping devices in airflow channels, as well as the complexity of installation, while at the same time providing improved control of airflow throughout an airflow system.

Abstract: A method and apparatus for delivering conditioned air using short duty cycles during which a damper is fully open for a time and fully closed for the remaining time. Conditioned air is continuously supplied to a plenum at low pressure and is applied to the space when the damper is open and blocked when the damper is closed. The proportion of on to off time during each duty cycle is adjusted to meet the load. When several supply terminals serve a space, their duty cycles are staggered to avoid fan instability. A special motor is coupled directly to the damper shaft for fast opening and closing of the damper. A magnetic latch holds the damper open or closed until the motor moves it again.

Abstract: A screen device is disclosed for attaching to, or making an overhead or roll-up door, one example being a garage door. The device is disclosed as an apparatus that is installed as a single or multiple units within or attached to a door, the apparatus comprising (1) a frame; (2) a louver mechanism attached to the frame, the louver of approximately the same size and shape as the frame, the louver mechanism operable to rotate open and close against the frame; (3) an opener for attaching the louver mechanism to the frame, and for maintaining the louver mechanism at a desired position of opening; and, (4) a screen or mesh immovably attached to the frame, and positioned relative to the louver mechanism so that the screen is obscured and shielded by the louvers of the louver mechanism, and when the louver is opened, the screen or mesh is revealed, and whereby the screen filters out objects that impinge upon the opening left by the frame, yet permit light and air to pass.

Abstract: An airflow shutdown system that includes an air distribution system and an air duct closure device. The air duct closure device is adapted to substantially instantaneously block airflow in the air distribution system when activated. The system also includes an integrated control system coupled to the air distribution system and adapted to activate the air duct closure device and stop an operation of other air distribution devices in the air distribution system in order to prevent migration of air through the system.

Abstract: A flap provided with an integral motor-containing drive element provided with an integral motor-containing drive element for controlling the air flow through an air-guide duct in, for example, a motor vehicle air condition system which includes a housing defining an air flow duct, an evaporator located in the housing, a heater located in the housing. The flap is adapted to be pivoted about and axis and is supported at each of its axial ends. One end is provided with a cut-out or recess which extends inwardly from one end along the axis of rotation. This cut-out or recess has opposed edges which engage in slots formed in holding means or housing that encloses the drive element, and which permit the ready insertion of the drive unit into an operative position.

Abstract: The present invention relates to a multi-valve damper which divides a section of an airflow duct into at least two airflow sections. The damper has a plug body having a proximal end and a distal end. The plug body is adapted to separate a section of an airflow duct into at least two airflow sections. At least two damper blades may be mounted on the distal end of the plug body, each of the damper blades controlling airflow in a respective airflow section. At least one airflow sensor may be provided in each of the airflow sections for controlling the respective damper blades. An actuator mechanism responsive to the sensors may be provided for opening and closing the damper blades.

Abstract: An air-guiding appliance (10) for the directionally defined introduction (R) of air (L) supplied on the rear side (20) of the appliance into a space (22), in particular interior of a vehicle, having a housing (26), at least one duct (24) in which the air (L) is supplied to the housing (26), an air-guiding device (12) which has recesses (14) on the front side and by means of which the direction (R) of the air flowing out into the space (22) can be defined, means for setting the direction (R) of the air-guiding device (12) and, if appropriate, means for setting the quantity of the air flowing into the space (22), is distinguished by the fact that a jet pipe (30) which can be displaced in and counter to the direction of the supplied air (L) is arranged in the housing (26) or in the duct (24) and its air outlet opening (28) is smaller in size than the cross-sectional surface of the air-guiding device (12), in which case, in the retracted position of the jet pipe (30), the air (L) emerges from the air-guiding devi

Abstract: Personal air supply devices integrated with chairs are adapted for use in conjunction with building or vehicle ventilation systems. The personal air supply devices include ducts, a tube and a nozzle arranged to direct a portion of the air from the building or vehicle ventilation system at the facial zone of a person sitting in the chair. The personal air supply devices include airflow regulating devices for regulating the flow of air through the nozzle. The tubes and nozzle are configured to release air from the ventilation system very close to the nose and mouth of a person in the chair to prevent mixing with ambient air and maximize the cooling and refreshing effect of the conditioned air. The building or vehicle ventilation system may be operated at lower ventilation rates without causing discomfort to persons provided with personal air supply devices.

Abstract: A programmable remote-control motion vent outlet includes an air vent arrangement and a control device. The air vent arrangement includes a ventilating guide adapted for mounting at a ventilating air outlet, wherein the ventilating guide has a ventilating slot for guiding an airflow passing from the ventilating air outlet to outside, a plurality of vent blades rotatably mounted to the ventilating guide for selectively allowing the airflow passing through the ventilating slot. The control device is adapted for remotely switching the vent blades between an air passage position and an air blockage position. In which, at the air passage position, the vent blades are rotated to open the ventilating slot respectively for allowing the airflow passing therethrough, and at the air blockage position, the vent blades are rotated to close the ventilating slot respectively for blocking the airflow passing through.

Abstract: A damper device includes a first baffle capable of opening or closing a first opening portion by turning about its axis and a second baffle capable of opening or closing a second opening portion by turning about its axis. A common drive source for driving the first baffle and the second baffle and a gear train by which the output from the drive source is transmitted to the first baffle and the second baffle are also provided. The device also includes a first rotary shaft driven by the gear train for driving the first baffle and a second rotary shaft driven by the gear train for driving the second baffle. The first rotary shaft and the second rotary shaft are arranged to be extended from the positions adjacent to each other on the gear train toward one side in an axial direction of the gear train.

Abstract: Methods and systems are provided for preventing contamination of building regions or zones from unwanted chemical or biological agents during and after a chemical or biological attack. One or more inflatable occlusion devices are preferably provided for occluding or filling selected regions within a building. The occlusion devices can be inflated to, for example, help prevent the building HVAC system or corresponding duct work from delivering a chemical or biological agent from one location to another within a building. The occlusion devices can also be used to occlude or occupy entire building regions or sections, such as entire rooms, hallways, windows, doorways, etc., or parts thereof, to help protect these regions from a harmful agent during an attack, and/or to provide a protective shell over or around selected equipment.

Abstract: A wall-mounted supply-air device comprising an upper valve part connected to an upper edge of an aperture in a primary wall side and a lower valve part connected to a lower edge of the aperture in the wall side, the supply air to the device being arranged to be supplied downwardly to the inlet side of the device, between the primary wall side and a secondary wall side in connection with the primary wall side.

Abstract: A motor operated butterfly valve arrangement, at least one valve element of which is to be brought into a proper extreme position such that water leakage or the like does not occur within the pipe controlled by the valve element, without the necessity to improve dimensional or mounting accuracy of the components and without the need to lock the motor actuating the valve element. An elastically deformable elastic coupling member is provided in a coupling mechanism interconnecting the motor and the valve element. As soon as the valve element reaches the desired extreme position in contact with a stopper, the motor is rotated to deform the elastic coupling member and to improve the contact between the valve element and the stopper. The motor is stopped in the deformed state of the elastic coupling member.

Abstract: An air vent damper assembly that controls air flow into the passenger compartment of an automotive vehicle and includes an air passage having a generally rectangular cross-section and a gasketless damper door. The damper door pivots between a closed position in which the door blocks airflow and a fully open position in which the door presents minimum obstruction to airflow. The damper door may be set at intermediate positions between closed and fully open to meter airflow and to direct air flowing from the exit end of the air passage.

Abstract: A motorized damper door assembly for use in freezing temperature applications includes a damper frame, a damper door having, a mounting portion rotatably mounted to the frame, and a seal member having a vertically extending moisture barrier adjacent the mounting portion. The door mounting portion and the moisture barrier together form a reservoir inside the door mounting portion to prevent moisture from seeping directly into the motor housing below the door mounting portion. Consequently, as moisture accumulation in the motor housing is avoided, associated damper jamming and impaired performance issues are also avoided.

Abstract: A differential mechanism is provided between first output shaft, to which the rotation of the drive motor is transmitted, and second output shaft, to which the rotation of first output shaft is transmitted, for adjusting the relative positions of these two output shafts. An air-mix door is connected to first output shaft, and a blowout mode door is connected to second output shaft. The rotation of the drive motor is used to operate the air-mix door and the blowout mode door in linkage, and the blowout mode door is designed to be able to be independently operated by the operation of movable lever of differential gear mechanism.

Abstract: A microwave oven comprising a main body formed with a cooking compartment, an outer casing surrounding the main body, to define an outer appearance of the microwave oven, a grill member provided between the main body and the outer casing, having a number of air passing holes, and a grill cover rotatably provided in front of the grill member, opening and closing the grill member, further comprising a main cam rotatably contacting with a rear face portion of the grill cover; a motor moving the main cam; and a switch sensing a rotational position of the main cam, the rotational position of the main cam being controlled to control the opening/closing operation of the grill cover when the motor operates. With this configuration, the switching operation is facilitated, the range of switching operation is constant, and the cost of production is reduced.