Motorized gear and coupling system

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. The wall plate has a first plate for housing the jack and a second plate with a flexible flange for removably securing the jack in the housing by snap fit insertion.

BACKGROUND

Worm and planetary gears work together to transfer rotational movement in one plane to another plane. The worm gear and planetary gear (also commonly referred to as a worm and worm gear, respectively) are placed in rotational engagement with each other so that the threads of the worm gear mesh with the teeth of the planetary gear. Thus, the longitudinal axis of the worm gear and that of the planetary gear are at right angles with each other so that rotational movement of one gear along its longitudinal axis is transferred to the other gear along its longitudinal axis.

The worm gear/planetary gear combination may be used to transfer the rotational movement of one shaft or other body to that of another shaft or body. This may be accomplished by coupling one of the shafts to the worm gear and the other to the planetary gear. Couplings are used to couple the shafts to the gears. In general, the couplings are separate elements, such as a nut or bearing, which must be separately attached to both the shaft and the gear. For example, the shaft may be inserted into the axle of the gear and held in place with a bearing.

The shafts coupled to the worm and planetary gears may by rotated manually. However, the gears can also be rotated by a motor. Thus, either the manual or motorized motion of one shaft is translated via the worm gear/planetary gear combination to another shaft or body.

SUMMARY

A gear system comprising a gear and coupling portion including a shaft, a worm gear, a planetary gear, a motor, and a means for controlling the motor is presented. The system may be supported by a bracket. The worm gear includes a coupler (a “worm coupling”) integrated with the worm gear's axle. Thus, the axle and the coupler form one integrated element. To attach a shaft (the “worm shaft”) to the worm coupling and a shaft (the “planetary shaft”) to the planetary gear, the worm shaft and the planetary shaft are inserted into the worm coupling and the planetary coupling, respectively. Both couplings include bores through which set screws are inserted so that they engage the shafts. Thus, the shafts are held in place. Shafts of different sizes and shapes may be accommodated by the distance by which the set screws are inserted into the couplings.

The worm coupling includes a head and an elongated portion. The elongated portion may be inserted into and fixedly attached to the worm gear. In this manner, the elongated portion serves as the axle of the worm gear. The head of the worm coupling includes an opening into which the worm shaft is inserted and to which it is removably attached. To attach the worm shaft to the worm coupling, the head may include one or more bores into which set screws may be inserted so that they contact the worm shaft. The cross-sectional shape of the coupling and the worm shaft are generally complementary.

The planetary coupling couples a shaft (the “planetary shaft”) with the planetary gear. The planetary coupling includes a bore into which the planetary shaft may be inserted and to which it is removably attached. To attach the planetary shaft to the planetary coupling, the planetary coupling may include one or more bores into which set screws may be inserted so that they contact the planetary shaft. By using a multiple of bores and set screws, such as four, the planetary coupling may accommodate planetary shafts with cross-sections significantly different and/or smaller than that of the planetary coupling. The cross-sectional shape of the planetary coupling and the planetary shaft may be complementary, however, this is not necessary.

The worm shaft is coaxially connected with a motor or gear-motor that rotates the worm shaft and, consequently, the worm gear. The motor is in electromechanical communication with the controller when the controller is connected to a modular interface. For example, the motor may be direct current, low voltage, low torque, and low rpm. The controller regulates the motor, particularly by activating and deactivating the motor as well as controlling the direction and distance the motor rotates the worm shaft. The controller also powers the motor, for instance, by battery. The controller may contain a processor and/or memory. The processor may be coupled to a sensor that deactivates the motor once the motor draws a certain level of current, indicating that the mechanism has reached the end of its range of motion.

The controller may be connected to the motor by an electrical connector, such as a plug and a jack for receiving the plug. The electrical connector may be mounted remotely from the motor by a wall plate comprising a first plate having a housing sized and shaped to receive the jack and a second plate having a flexible flange for removably securing the jack in the housing.

DETAILED DESCRIPTION

A gear and coupling system is shown inFIGS. 1 and 2. The system100generally includes a worm gear coupling200, worm gear300, planetary gear400and planetary gear coupling500. As shown inFIGS. 1 and 2, the system100may be mounted on a bracket800. The bracket800may include configurations that maintain the functional relationship among the elements of the system100. The worm gear300and the planetary gear400are mounted at right angles to each other so that the threads302of the worm gear300intermesh with the teeth402of the planetary gear400. In this arrangement, rotation of the worm gear300around its longitudinal axis will cause the planetary gear400to rotate around its longitudinal axis.

The worm gear coupling200includes a head202and an elongated portion204. The worm gear300is coaxially attached around the elongated portion204along the longitudinal axis of the elongated portion204. Thus, the elongated portion204serves as the axle of the worm gear300in one integrated element. The head202includes a bore210for receiving a set screw206. Although one bore210and one set screw206are shown, a variety and number of bores210and set screws206may be included. The head also includes an opening208.

The planetary gear coupling500is fixedly and coaxially attached to the planetary gear400. In a preferred embodiment, planetary gear400and planetary gear coupling500are formed integrally as a single element. The planetary gear coupling500may include a number of bores506for receiving a number of set screws502. Although four bores506and set screws502are shown inFIGS. 1 and 2, a variety and number of bores506and set screws502may be included.

Worm gear coupling200, worm gear300, planetary gear400and planetary gear coupling500may be formed of various materials that are known in the art, including metal and plastic. In a preferred embodiment, worm gear coupling200and worm gear300(and/or planetary gear400and planetary gear coupling500) are integral and formed as a single element. Worm gear coupling200, worm gear300, planetary gear400and/or planetary gear coupling500may be made of various materials that are known in the art, including metal, nylon or acetal resin, and may be formed by milling, casting, molding or other methods known in the art that are appropriate to the material.

The gear and coupling system100may be used to translate the rotational motion of one body to another body along a different axis. For example, as shown inFIGS. 3 and 4, the system100may be used to translate the rotational movement of one shaft (a worm shaft600) around the longitudinal axis of the worm gear300to another shaft (a planetary shaft700) around the longitudinal axis of the planetary gear400. The worm shaft600may serve as the drive shaft for the system100. The worm shaft600and the planetary shaft700may be a rigid or flexible body, such as a flexible cable.

The worm shaft600may be removably coupled to the worm gear300via the worm coupling200. As shown inFIGS. 5 and 6, the elongated portion204of the worm coupling200is inserted into the bore304in the worm gear300. For example, the elongated portion204of the worm coupling200may be knurled and slightly larger in diameter than the bore304. The elongated portion204is press fit into the worm gear300. To couple the worm shaft600with the worm gear300, the worm shaft600is inserted into the opening208in the head202of the worm coupling200and secured therein by one or more set screws206. In addition to coupling the worm shaft600with the worm gear300, the worm coupling200, particularly the elongated portion204, serves as the axle of the worm gear300. Thus, rotation of the worm shaft600will cause the worm gear300to rotate along its longitudinal axis.

Referring again toFIGS. 3 and 4, the planetary shaft700may be removably coupled with the planetary gear400via the planetary coupling500. The planetary shaft700is inserted into the bore504in the planetary coupling500and secured therein by the set screws502. As shown inFIGS. 3 and 4, the planetary coupling500includes four bores504and four set screws502.

The opening208in the worm coupling200may have a variety of cross-sectional shapes, which are generally complementary to the shape of the cross-section of the worm shaft600. For example, as shown inFIG. 5, the opening208and the cross-section of the worm shaft600proximate to the worm coupling200has a square shape. Alternately, the opening208and the cross-section of the worm shaft600may have other shapes for example, circular or hexagonal. The bore504in the planetary coupling500may have a circular cross-section, which may receive planetary shafts700of various cross-sectional shapes, such as circular, square (which is shown inFIGS. 3 and 4) and hexagonal. By using a multiple of bores504and set screws502, such as four, the planetary coupling500may accommodate planetary shafts700with cross-sections significantly smaller than that of the planetary coupling500.

The system may be supported by a bracket800. One example of such a bracket800is shown inFIGS. 1-4. As shown inFIGS. 3 and 4, the bracket may include a lower support802, a side support808and an end support810. The worm gear300and the planetary gear400are supported by the lower support802. The planetary gear400is secured to the lower support802so that its longitudinal axis is about perpendicular with the lower support802. The planetary gear400may go through a bore504in the lower support802and be attached to the bore504via a snap ring or retaining ring (not shown) located on the side of the lower support802opposite the planetary coupling500. The lower support802includes a pair of protrusions806and807that support the worm coupling200. The protrusions806and807each include a bore811and809, respectively, through which the axle of the worm gear300(the elongated portion204of the worm coupling200) is inserted. To secure the worm gear300in the bracket800, the elongated portion204may be knurled and inserted through protrusion806, press fit into the worm gear300and then extended through the other protrusion807. The worm gear300and the planetary gear400are located on the lower support802of the bracket800in such proximity with each other so that the threads302of the worm gear300mesh with the teeth402of the planetary gear400.

The side support808of the bracket800attaches the lower support802to the end support810so that the end support810faces the lower support802. The end support810may include a bore812through which the worm shaft600may protrude. This arrangement provides support to the worm shaft600and aligns the longitudinal axis of the worm shaft600with that of the worm coupling200.

The bracket800may be manufactured from a material such as metal or engineered plastic. The bracket800may be made from a single piece of material (for example, stamped in one piece from a single sheet of metal) and folded to obtain the desired shape. Alternately, the components of the bracket800may be manufactured separately and secured together via, for example, welding, screwing and/or soldering.

In an alternative embodiment, instead of having bores811and809, protrusions806and807may be formed as yokes having an opening on the side toward the planetary gear. Referring toFIG. 8, a gear and coupling system is shown having a worm gear350and a planetary gear450that are mounted on a bracket850. Bracket850is provided with yokes856and857having openings858and859, respectively, on the side toward planetary gear450. Axle352of worm gear350is inserted in openings858and859and supported on yokes856and857. Axle352is further provided with a collar354and radial flange356that are positioned outside of yokes856and857, respectively. Both collar354and radial flange356have diameters that are larger than openings858and859, to prevent worm gear350from slipping laterally within yokes856and857. The assembly of planetary gear450on bracket850prevents worm gear350from inadvertently lifting out of yokes856and857and further secures worm gear300in place.

One application for which a gear and coupling system may be used is shown inFIG. 7. In this example, the gear and coupling system100is used to control the motion of a damper904within a plenum900, such as a heating, ventilation and air conditioning (HVAC) duct. In the plenum900, airflow is controlled by the position of the dampers904. If the dampers904are positioned so that they are parallel with the top902of the plenum, the maximum amount of air is permitted to flow. In contrast, if the dampers904are positioned so that they are perpendicular with the top902of the plenum, air is restricted from flowing through the plenum900. Movement of the dampers904is controlled by the rotation of the planetary shaft700.

Due to the size and the shape of the aperture504and set screws502(seeFIG. 3) in the planetary coupling500, planetary shafts700of different sizes and shapes may be accommodated. For example, the aperture504and set screws502(seeFIG. 3) may accommodate a 0.25 or 0.375 inch square shaft. Alternately, the aperture504and set screws502(seeFIG. 3) may accommodate 0.25 or 0.5 inch round shaft700.

Such plenums900may be located in areas that are not conveniently or easily accessible. For example, the plenum900may be located in a ceiling, wall or floor. Therefore, some type of device is needed to enable the dampers904to be remotely controlled. This device may include a worm shaft600. The worm shaft600may include, for example, a flexible or non-flexible cable. If the plenum900is installed in a ceiling, the worm shaft600, which is in communication with the worm coupling200, may protrude from the ceiling. Thus, the dampers904may be controlled by rotating the protruding worm shaft600.

In an alternative embodiment, the rotation of the worm shaft may be driven by a motor. Referring toFIGS. 9 and 10, a motorized gear and coupling system1000is shown, which generally includes a worm gear coupling1200, worm gear1300, planetary gear1400and a planetary gear coupling500, that are mounted on a bracket1800. A worm shaft1600is coupled with worm gear1300through worm coupling1200. A motor1100is mounted on end support1810of bracket1800, that is connected with and configured to rotate worm shaft1600. The motor1100may have an output shaft that serves as a drive shaft and is inserted directly into the worm coupling1200, thus eliminating the need for a separate worm shaft. Motor1100may be removably mounted on bracket1800using bolts, screws or other fasteners (not shown) that are well known in the art. Motor1100is operated by a controller1102, which is in electromechanical communication with the motor via a cable1104.

Motor1100is preferably a direct current, low voltage motor (e.g., a 9 V, 12 V or 18 V motor) having low rpm and low torque. As is well known in the art, motor1100may be a gear-motor that includes a gear set1101to gear down the speed of the motor to accommodate the requirements of a particular application. When motorized gear and coupling system1000is used to control the motion of a damper, it is presently preferred that motor1100be geared down such that it takes approximately 10-15 seconds for the dampers to move from a position of maximum airflow to a position of minimum airflow (or vice versa). It has been found that a motor and gear set that rotates worm shaft1600in a range of about 30 rpm to about 35 rpm is particularly useful for controlling dampers when the gear and coupling system includes a worm gear and planetary gear. However, those of skill in the art will appreciate that the gear ratio of the worm gear and planetary gear (or other intervening gearing between the motor and the damper) may also be a factor in determining the optimal motor speed.

As best shown inFIGS. 9 and 10, controller1102includes a switch1106, a control module1108, a user interface1110and a power supply1112. Control module1108includes a microprocessor1114and a sensor1116. User interface includes an input1120and a display1122. In a preferred embodiment, controller1102is a portable handheld device having a housing1103that contains switch1106, control module1108, user interface1110and power supply1112. Housing1103may be ergonomically designed and may be provided with a textured grip1105. Housing1103may be provided with other features to enhance its portability, such as a belt clip and/or retractable reel (not shown).

Motorized gear and coupling system1000is operated by actuating switch1106, which provides a signal to microprocessor1114via input1120. Microprocessor1114, in turn, provides a current from power supply1112through cable1104to motor1100, to drive worm shaft1600and operate gear and coupling system1000. Sensor1116monitors the operation of motor1100and provides a signal to microprocessor1114. Based on the signals from switch1106and/or from sensor1116, microprocessor1114directs display1122to provide an indicia that reflects the operational condition of gear and coupling system1000and/or controls the current provided to motor1100from power supply1112.

In a preferred embodiment, switch1106is a 3-position rocker switch having a rest position, a first position1106aand a second position1106b. Actuating switch1106at the first position1106asends a first signal to microprocessor1114to provide a current from power supply1112and operate motor1100to rotate worm shaft1600in a first, forward direction. Actuating switch1106at the second position1106bsends a second signal to microprocessor1114to reverse the polarity of the current from power supply1112and operate motor1100to rotate worm shaft1600in a second, reverse direction. When neither position1106anor1106bare actuated, switch1106returns to the rest position and no current is provided to motor1100. Those of skill in the art will appreciate that other type of switches may be used, such as separate buttons2106aand2106bfor forward and reverse, rather than a rocker switch, as shown inFIG. 11.

In a further preferred embodiment, sensor1116detects the level of current draw by motor1100. In a first operating condition, motor1100rotates freely and sensor1116detects a first level of current draw and sends a first signal to microprocessor1114. In a second operating condition, motor1100experiences resistance to rotation which increases the current draw by the motor. Sensor1116detects the increased current draw and sends a second signal to microprocessor1114to shut off the current from power supply1112to motor1100.

Display1122is controlled by microprocessor1114in response to signals from rocker switch1106and/or sensor1116. In a preferred embodiment, display1122comprises LEDs1124aand1124bthat provide indicia of the operating condition of motor1100. As best shown inFIG. 9, LEDs1124aand1124bpositioned to correspond to first and second positions1106aand1106bof a rocker switch1106. The actuation of rocker switch1006at first position1106asends a first signal to microprocessor1114which, in turn, directs first LED1124ato provide a first indicia that motor1100is rotating in a first direction. When motor1100experiences resistance to rotation, such as when worm shaft1600is prevented from rotating, sensor1116sends a second signal to microprocessor1114which, in turn, directs first LED1124ato provide a second indicia that motor1100has experienced a change in operating condition. LED1124bsimilarly provides indicia that motor1100is operating in a second, reverse direction, and whether motor1100has experienced a change in operating condition.

For example, when motorized gear and coupling system1000is used to control the motion of a damper, actuating rocker switch1106at position1106acauses the motor to rotate in a first direction and causes LED1124ato turn green, indicating that the dampers are moving toward an open position to allow maximum airflow. Once the dampers are in the fully open position and have reached the end of their range of motion, worm shaft1600is prevented from further rotation, the current to motor1100is shut off, and LED1124aturns red to indicate that the dampers have stopped moving and are fully open. Conversely, when rocker switch1106is actuated at position1106b, motor1100operates in reverse and LED1124bturns green, indicating that the dampers are moving toward a closed position to restrict airflow. Once the dampers are in the fully closed position and have reached the end of their range of motion in the opposition direction, worm shaft1600is once again prevented from further rotation, the current to motor1100is shut off, and LED1124bturns red to indicate that the dampers have stopped moving and are fully closed, resulting in a minimum of airflow.

Power supply1112may be of any type sufficient to operate motor1100. In a preferred embodiment, power supply1112is a low voltage power supply that is small enough for a portable device and is easily replaced, such as a 9 V battery. Controller1102may include a shutoff switch1126to turn off the controller and prevent the battery from being drained by the continuing draw from microprocessor1114or by the inadvertent actuation of switch1106.

Controller1102is connected to motor1100by a cable1104. Cable1104may be of any type suitable for the application. For example, when motorized gear and coupling system1000is used to control a damper, cable1104is preferably a two conductor, plenum rated cable or similar fire rated cable. The connections between cable1104and motor1100and/or between cable1104and controller1102may be soldered or may use any of a variety of electrical connectors that are known in the art. In a preferred embodiment, cable1104is detachably connected to controller1102, to create a modular system where a single controller may be used with multiple different motorized gear and coupling systems1000. As shown inFIG. 9, cable1104has an end1104athat terminates in a standard 2.1 mm connector mini power plug1128. Controller1102is provided with a corresponding mini power jack1130for receiving plug1128. Those of skill in the art will appreciate that other types of detachable electrical connectors may be used, depending on the voltage of the power source and the type of information that is transmitted between motor1100and controller1102.

Referring toFIGS. 11aand 11b, an alternative embodiment of a motorized gear and coupling system is shown that is adapted to operate a damper. Motorized gear and coupling system2000generally comprises a worm gear/coupling2200, planetary gear/coupling1400and motor2100that are mounted on a bracket2800, a cable2104and a controller2102. Bracket2800is mounted at a plenum2010, such as a ceiling plenum for use in an HVAC system. Preferably, motorized gear and coupling system2000is mounted on plenum2010, but may also be mounted on the damper or a nearby structure. A damper (not shown) is mounted within plenum2010to regulate airflow, and is operated by motorized gear and coupling system2000.

Cable2104extends from motor2100at plenum2010to a remote location and terminates in a detachable electrical connection2128. In a preferred embodiment, electrical connection2128is mounted in a wall2004at a location that is conveniently accessible to the user. This configuration permits the gear and coupling system, including the motor, to be installed on a plenum, leaving the controller as the only external part of the system.

Controller2102includes a cable2132that has a first end2132athat is connected to the controller and a second end2132bthat terminates in a detachable electrical connection2134which corresponds to detachable electrical connection2128of cable2104. In a preferred embodiment, detachable electrical connections2134and2128are a mini power plug and jack, respectively. End2132aof cable2132may be connected to controller2102by soldering or may use any of a variety of electrical connectors that are known in the art. In a preferred embodiment, end2132aof cable2132is also connected to controller2102by a detachable electrical connection, such as a mini power plug/jack.

As best shown inFIG. 11b, a modular system may include a wall plate2138for mounting multiple electrical connections2128corresponding to different motorized gear and coupling systems. Wall plate2138is installed at a convenient location, such that multiple motorized gear and coupling systems at different locations may be easily controlled by alternately connecting the plug2134of a controller2102into the various electrical connectors2128. Indicia2140may be provided on wall plate2138to identify the different motorized gear and coupling system associated with each electrical connection2128.

In a further alternative embodiment, the controller may provide the user with additional information, such as battery life, identification of the damper being controlled, the position of the dampers relative to the fully open/closed position, and other information. To accommodate these additional features, the controller may be provided with an alphanumeric display2136, rather than simple LEDs. The controller may also include a memory1118to store data. In addition, cables2104and2132may be four conductor cables with appropriate electrical connectors2128,2134.

Those of skill in the art will appreciate that the motorized gear and coupling system described herein is not limited to a worm gear and planetary gear, but may be adapted for use with other gearing systems, such as miter gears or a friction drive. Furthermore, in some cases, the operation of a damper may not require the translation of rotational movement, but may be directly driven by the motor through a drive shaft.

Referring toFIGS. 12 and 13, an alternative embodiment of a system for controlling airflow through a plenum is shown. A rotary damper3000and a motor3100are mounted on a bracket3800. Motor3100is directly connected to rotary damper3000by a drive shaft3600, without intervening gearing. Rotary damper3000may be removably coupled to drive shaft3600by a coupling (not shown) in the same manner as previously described couplings200and500. A controller (not shown) is connected to motor3100by cable3104.

The movement of rotary damper3000between open (maximum airflow) and closed (restricted airflow) positions is controlled by the rotation of drive shaft3600. The operation of motor3100causes drive shaft3600to rotate damper blades3136and either open or close damper3000, depending on the direction of rotation of the motor. Those of skill in the art will appreciate that it requires less than a single revolution of drive shaft3600to rotate damper blades3136from a fully open to a fully closed position (or vice versa). Thus, in a preferred embodiment, motor3100is a gear-motor that contains an appropriate gear set3101to gear down the motor and ensure that it takes approximately 10 to 15 seconds for damper blades3136to move between open and closed positions. It has been found that a gear motor capable of rotating drive shaft3600at a speed of about 2.5 rpm is particularly useful.

Referring toFIG. 13, rotary damper3000and motor3100are shown mounted in a plenum3900to control the airflow through the plenum. Thus, motor3100is positioned in the airstream when used in an HVAC system or other regulated airflow system. Cable3104may extend from motor3100through plenum3900to a remotely located diffuser3902or other opening in the plenum system. In a preferred embodiment, diffuser3902is located in a ceiling3004or other structure where the end3104aof cable3104is conveniently accessible for connection to a controller. End3104aof cable3104is provided with a detachable electrical connector3128(e.g., a mini power jack) for connection to the corresponding detachable electrical connector3134(e.g., a mini power plug) of a controller. In addition, end3104amay be secured to plenum3900at or near diffuser3902, using a clamp3132or by other means known in the art.

In an alternative embodiment, cable3104may exit the plenum through a hole in the wall of the plenum (not shown) that is made by drilling, punching or other means known in the art. The hole may be provided with a grommet (not shown) to protect cable3104from fraying or shearing caused by the edges of the hole. Cable3104extends from motor3100at plenum3900to a remote location and terminates in a detachable electrical connection, such as previously described wall plate2138.

Referring toFIGS. 16a, 16b, 17aand 17b, a preferred embodiment of a wall plate for mounting multiple detachable electrical connectors remotely from the motor is shown. Wall plate5000comprises a front plate5010for receiving the electrical connectors, a rear plate5012for removably securing the electrical connectors in the wall plate, and a mounting bracket5014. Front plate5010is installed over an opening in a wall or other structure that provides access to one or more cables3104. As best shown inFIGS. 16aand 17a, the front side5016of front plate5010is provided with multiple openings5018that are sized and shaped to permit insertion of an electrical connector, such as mini power plug3134. Front plate5010is further provided with holes5020for receiving screws5022or other fasteners to secure the front plate to mounting bracket5014. Alternatively, front plate5010may be screwed to an electrical wall box or other structure, as is known in the art. As best shown inFIGS. 16band 17b, the rear side5024of front plate5010has multiple rearwardly projecting housings5026with openings5028, that are sized and shaped to receive an electrical connector, such as mini power jack3128. Each housing5026is positioned to correspond to, and is accessible through, an opening5018of front side5016.

Rear plate5012is provided with multiple wells5030having a front opening5032that are positioned to correspond to housings5026of front plate5010. Each well is sized and shaped to receive a housing5026of front plate5010. Wells5030are provided with a rear opening5034that is defined by one or more inwardly projecting flanges5036for receiving and securing mini power jack3128in housing5026.

Wall plate5000is assembled by fitting rear plate5012onto rear side5024of front plate5010, such that wells5030of the rear plate fit over housings5026and cover the openings5028of the front plate. Because flanges5036are inwardly projecting, opening5034on rear plate5012is smaller than housing5026, such that housing5026cannot pass through and rests within well5030. Rear plate5012is preferably coupled to front plate5010by interference or friction fit. To facilitate the alignment and friction fit of the front and rear plates, one or more complementary pins5038and5040may be provided on front and rear plates5010and5012, respectively, as best shown inFIGS. 17aand17b.

One or more mini power jacks3128(or other electric connectors) are mounted in wall plate5000by snap fit insertion of the mini power jack through opening5034on rear plate5012and into opening5028/housing5026of front plate5010. Because flanges5036are inwardly projecting, opening5034on rear plate5012is smaller than mini power jack3128. As best shown inFIG. 16b, when the mini power jack (3128a) is inserted into opening5034, flanges5036are sufficiently flexible to deflect from their original positions and allow opening5034to enlarge and accommodate insertion of the mini power jack. Once mini power jack (3128b) is fully inserted past flanges5036, flanges5036and opening5034return to their original positions to snap fit and removably secure the mini power jack within housing5026. The interior surface5046of flanges5036which defines opening5034may be inclined to facilitate the deflection of flanges5036and the insertion of mini power jack3128through opening5034. In addition, interior surface5046of flanges5036may be provided with a sharply inclined lip5048to increase the difficulty in withdrawing mini power jack3128past flanges5036and through opening5034after the mini power jack is fully inserted in housing5026.

Once mini power jack3128is inserted into housing5026, it is accessible and may be connected to a complementary mini power plug3134through an opening5018of front plate5010. As best shown inFIG. 16a, openings5018are sized and shaped to permit connection between mini power plug3134and mini power jack3128, but are too small to permit the mini power jack to be removed from housing5026. Indicia5050may be provided on front plate5010adjacent to each opening5018, to permit ready identification of the mini power jack mounted within the corresponding housing5026. A cover plate (not shown) may also be provided to conceal openings5018and give front plate5010a uniform appearance when not in use. Openings5052may be provided in front plate5010to attach the cover plate to the front plate by snap fit or other means known in the art.

The assembled wall plate5000is typically mounted over an opening in the wallboard panel of a wall (or other structure), through which the mini power jack(s)3128or other electrical connector is accessed. Mounting bracket5014is placed over the opening in the wall and tabs5044are manually bent outward from wall plate5000to extend behind the wallboard paneling (shown inFIGS. 16band 17b) and secure the mounting bracket to the wall. Holes5042are provided in mounting bracket5014, that are positioned to correspond to holes5020in front plate5010. Once front plate5010, rear plate5012and mini power jack(s)3128are assembled, the front plate is placed over mounting bracket5014such that holes5020and5042are aligned and the front plate and mounting bracket are secured together by screws5022to complete the installation of wall plate5000on the wall.

Front plate5010and rear plate5012may be made of plastic or other materials known in the art. In a preferred embodiment, front plate5010and rear plate5012are made of injection molded ABS plastic. Mounting bracket5014is similar in construction and use to commercially available low voltage mounting brackets for exiting construction.

Referring toFIGS. 18aand 18b, an alternative embodiment of a wall plate is shown for mounting a single electrical connector remotely from the motor. Wall plate5100comprises a front plate5110and a rear plate5112. Front plate5110has a front side5116with an opening5118. The rear side5124of front plate5110has a housing5126with an opening5128that are sized and shaped to receive an electrical connector, such as a mini power jack3128.

Rear plate5112is provided with a well5130having a front opening5132that is sized and shaped to receive housing5126of front plate5110. Well5130is provided with a rear opening5134that is defined by an inwardly projecting flange5136. Rear opening5134is sized and shaped to receive end3104aof mini power jack cable3104. A slot5138is formed in rear plate5112that is sized and shaped to receive cable3104, and that extends the length of well5130and connects front opening5132and rear opening5134.

Wall plate5100is assembled by fitting rear plate5112onto rear side5124of front plate5110, such that well5130of the rear plate fits over housing5126and covers opening5128of the front plate. Similarly to the assembly of wall plate5000, flange5136is inwardly projecting such that opening5134on rear plate5112is smaller than housing5126, and the housing cannot pass through and rests within well5130. Rear plate5112is preferably coupled to front plate5110by friction fit. Housing5126may be provided with ribs5140that are sized and shaped to be complementary to slot5138in rear plate5112, and to facilitate the alignment and friction fit of the front and rear plates5110and5112.

Similarly to the operation of wall plate5000, a mini power jack3128(or other electric connector) is mounted in wall plate5100by inserting the mini power jack through opening5128and into housing5126. The end3104aof mini power jack cable3104is threaded through slot5138in rear plate5112, such that cable3104is received in and projects out of rear opening5134. Rear plate5112is then friction fit over housing5126to removably secure mini power jack3128within housing5126, as shown inFIG. 18a.

In a preferred embodiment, wall plate5100is designed to be installed on wallboard or a similar structure without the need for screws or other fasteners. A hole is drilled or cut into the wallboard (not shown) having a diameter that is slightly smaller than the size of well5130of rear plate5112. Mini power jack3128is fed through the hole and mini power jack cable3104is is threaded through slot5138in rear plate5112. Well5130is then press fit into the hole until rear plate5112is flush with the surface of the wallboard. Mini power jack3128is received in housing5126and front plate5110is friction fit with rear plate5112to complete the installation of wall plate5100. Ribs5154may be formed on the exterior surface of well5130to help secure wall plate5100in the wallboard structure. Once mounted in wall plate5110, mini power jack3128is accessible and may be connected to a complementary mini power plug3134through opening5118of front plate5010in a similar manner as previously described. Because of its small size, a cover plate5156for concealing opening5118may be integrally formed with front plate5110.

Wall plate5000and5100may be made of plastic, metal or other materials known in the art. In a preferred embodiment, the wall plate is made of a non-conductive material, such as injection molded nylon.

Referring toFIGS. 14 and 15, a preferred embodiment of a damper system is shown that provides a continuous indication of the relative position and direction of rotation of the damper between the open and closed positions. Controller4102is provided with a display4123comprising a series of LEDs that provide a graphic representation of the position of the damper4000between the open and closed positions. In a particularly preferred embodiment, display4123is a linear array of LEDs4124a-4124zthat provide a continuous sequence of indicia corresponding to the relative position of the damper between the open and closed positions. For example, when the damper is in the fully open position, actuating controller rocker switch4106at position4106bcauses damper4000to rotate toward the closed position and causes display4123to show a first indicia in which the first LED4124ain the linear array turns green. As the rotation of damper4000progresses to the closed position, display4123sequentially shows a second indicia in which LEDs4124aand4124bare green, a third indicia in which LEDs4124athrough4124care green, etc. This sequence of indicia continues until the damper reaches the fully closed position and all of LEDs4124athrough LED4124zare turned on. The number of green LEDs4124shown in display4123thus provides a continuous indication of the position of damper4000relative to the open and closed positions during the operation of the damper. To indicate that damper4000is in the fully closed position and rotation has stopped, last LED4124zmay turn red rather than green.

To open damper4000, rocker switch4106is actuated at position4106aand the operation of display4123is reversed with LEDs4124sequentially turning green beginning with LED4124zuntil LED4124ais reached and turns red, indicating that the damper is in the fully open position and has stopped rotating. The direction of rotation is readily determined by observing whether LEDs4124are turning green from “a to z” direction (closing) or the “z to a” direction (opening), or by observing whether LED4124aor LED4124zhas turned red.

Continuous display4123provides a fast and reproducible method of balancing airflow without the repeated use of an airflow meter. Once the airflow of a plenum system has been balanced, the relative position of each damper in the system may be recorded as the number of green/red LEDs4124shown in display4123. If the system is later adjusted, the balance is easily restored without the need for an airflow meter, by resetting the dampers to their appropriate positions as indicated by the number of the number of green/red LEDs4124. This ability to quickly and reproducibly reset the balance is particularly useful where there is a need for periodic adjustment of the airflow, such as between seasons. Thus, continuous display4123provides a distinct advantage over conventional damper systems which do not provide any indication of the position of the damper between the open and closed positions, or that may only provide a rough indication of the midpoint position.

As shown inFIG. 14, display4123comprises ten LEDs4124. However, those of skill in the art will appreciate that display4123may comprise any number and/or arrangement of LEDs4124. For example, in the case of a rotary damper, it may be desirable to arrange LEDs4124in a circular pattern to reflect the configuration of the damper. In a preferred embodiment, an even number of LEDs4124are used, to accurately represent the midpoint between the open and closed positions.

The position of damper4000between the open and closed positions may be determined using microprocessor1114, as shown inFIG. 10. For example, using a constant speed motor4100, microprocessor1114can be programmed to determine the position of damper4000based on the time of rotation. If a gear and coupling system is required, such as system1000shown inFIG. 9, the known gear ratio of worm gear1300and planetary gear1400may also be taken into account when calculating the position of damper. Microprocessor1114then directs display4123to provide the proper indication of the position of the damper by turning on the appropriate LEDs4124.

In some cases, the overrotation of damper4000past the fully open or closed position may create errors when time of rotation is used to determine the position of the damper. Thus, damper4000preferably incorporates a mechanism to prevent overrotation. As shown inFIG. 15, rotary damper4000comprises a number of blades4136that rotate relative to each other about a common axis (i.e. drive shaft4600), thereby defining a blade rotation plane. Typically, only a single blade is directly connected to and driven by the drive shaft4600. The rotation of all of blades4136is coordinated by one or more pins4140that travel within corresponding slots4142. As blades4136reach the fully open or fully closed position, slot4142restricts the movement of pin4140which, in turn, restricts the relative rotation of the blades.

In some cases, a manually driven cable or a motor4100may provide sufficient torque to force pin4140out of slot4142, permitting the overrotation of blades4136beyond the fully open or fully closed positions. In a preferred embodiment, one or more flanges4138are formed at the edge4137of blade4136a. Flanges4138project orthogonally to the blade rotation plane and form a stop that restricts the rotation of the other blades4136beyond edge4137and, consequently, restricts overrotation. In a particularly preferred embodiment, flanges4138are positioned at the end of the blade4137afurthest from the axis of rotation to minimize any gaps between the blades in the fully closed position and to increase the resistance to torque.

While various embodiments have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.