Abstract:
A damper has a plurality of blades movable between an open and a closed position in response to an operating/actuating means attached to the blades. A shaft rotatable about its axis has lever arm means attached to it and to said blades, to open and close said damper in response to rotation of said shaft for 180 degrees of travel. Connector arm means are pivotally connected to crank arms and pivotally connected to said blades at pivot point locations such that the pivot points of said pivotal connections are over center of the plane of the axis of said shaft when the blades are in the open and closed positions.  
     Limit switches are provided to automatically stop the travel of the blades at fully open and fully closed positions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a Continuation-in-Part of our prior provisional applications, namely MULTIBLADE DAMPER WITH DC ACTUATOR AND DOUBLE KNEE LOCK BLADE OPERATOR, Ser. No. 60/293,678, filed May 25, 2001; MULTIBLADE MODULATING DAMPER WITH A CHAIN DRIVE, Ser. No. 60/293,639, filed May 25, 2001; CHAIN OPERATOR DRIVE FOR A BUTTERFLY DAMPER WITH DOUBLE ACTING OVER CENTER LOCK, Ser. No. 60/293,656, May 25, 2001; and utility application for DRIVE FOR BUTTERFLY DAMPER WITH DOUBLE ACTING OVER CENTER LOCK, Ser. No. 10/015312, filed Dec. 11, 2001; the disclosures of all of which are incorporated herein by reference as if fully set forth. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Technical Field  
           [0003]    This invention relates to air/fire/smoke multiblade dampers and, in particular, to a mechanism for operating said dampers and maintaining those dampers in a fully opened, partially opened, and fully closed position.  
           [0004]    2. Background Art  
           [0005]    In the prior art, a variety of means are known for operating dampers to move the blades from a closed to an open position and to return them to the closed position. When electric motors were used to open the dampers and close them, the motors typically had only 90 degrees of rotation.  
         DISCLOSURE OF THE INVENTION  
       SUMMARY OF THE INVENTION  
         [0006]    This invention provides actuators/operators for air, smoke and fire control dampers with 180 degree drive shaft arm rotation from over center held locked open to over center held locked closed. The apparatus automatically stops in either direction, can reverse, or can continue in the same direction.  
           [0007]    In one embodiment, a switch means may be provided to cut the power to the motor driving the damper actuator; and in that event, the damper will be maintained in its partially opened position.  
           [0008]    In accordance with the preferred and/or alternate embodiments of our invention it comprises a damper having at least one blade movable between a first position in which the damper is closed by said blade and a second position in which the damper is opened by said blade, upon movement of an operating/actuating means attached to said blade, wherein there is an improvement comprising:  
           [0009]    said operating/actuating means further comprising a direct current motor connected to a power source for supplying electricity to operate said motor and move said blade; and  
           [0010]    control means connected to said motor and said power source to control the flow of electricity there between, comprising limit switch means for interrupting the flow of electricity to the motor to stop it and thereby stop the movement of the blade in at least one of said positions.  
           [0011]    The limit switch means further comprises at least one or a plurality of micro switches.  
           [0012]    The operating/actuating means further comprises engagement means for engaging at least one micro switch to operate said switch upon certain movement of said engagement means, and thereby interrupt the flow of electricity to said motor as aforesaid; or the operating/actuating means further comprises engagement means for selectively engaging one and another of said plurality of micro switches to operate said switches upon certain movements of said engagement means, and thereby interrupt the flow of electricity to said motor as aforesaid.  
           [0013]    The operator/actuator means further comprises lever means comprising a plurality of levers pivotally connected to one another; and the engagement means further comprises a striker means attached to one of said levers for engaging at least one micro switch to operate said switch upon certain movement of said engagement means, and thereby interrupt the flow of electricity to said motor as aforesaid; or the operating/actuating means further comprises lever means comprising a plurality of levers pivotally connected to one another; and the engagement means further comprises a striker means for selectively engaging one and another of said plurality of micro switches to operate said switches upon certain movements of said engagement means, and thereby interrupt the flow of electricity to said motor as aforesaid.  
           [0014]    The motor has a shaft which can rotate at least 180 degrees when the motor is operated; and said shaft is connected to said lever means to move said lever means in response to movement of said motor shaft.  
           [0015]    The motor has a shaft which can rotate at least 180 degrees when the motor is operated; and said shaft is connected to said lever means to move said lever means in response to movement of said motor shaft.  
           [0016]    In operation, the motor is reversed by a change in the direction of the flow of electrical current thereto, thereby reversing the direction of rotation of the motor shaft and reversing the movement of said lever means.  
           [0017]    The control means further comprises additional power interrupt means to cutoff the flow of electricity to said motor and thereby stop said motor and further, to thereby stop said blade in any of said positions and between said positions.  
           [0018]    The operator/actuator means further comprises lever means comprising a plurality of levers pivotally connected to one another and arranged to provide an over center lock to prevent reverse movement of said operating means when the flow of electricity to said motor is cut off and said blade is stopped in any of said positions.  
           [0019]    The operator/actuator means further comprises additional mechanical means to prevent reverse movement of said operating means when the flow of electricity to said motor is cut off and said blade is stopped in any of said positions, and between said positions.  
           [0020]    The control means further comprises micro switches having at least three terminals, consisting of a neutral terminal, a normally open terminal and a normally closed terminal; and a diode means comprising a diode is connected between the normally open and normally closed terminals to control the flow of current there between.  
           [0021]    The motor has at least two terminals; and the power source has at least two terminals; and the control means further comprises: electrical circuitry means comprising an electrical connector between one terminal of the power source and the neutral terminal of one micro switch; an electrical connector between one terminal on the motor and one terminal on one micro switch; and an electrical connector between another terminal of the power source and the neutral terminal of another micro switch; and an electrical connector between another terminal on the motor and one terminal on another micro switch. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0022]    [0022]FIG. 1 is a perspective view taken from the right front side of a damper with the blades shown in a closed position;  
         [0023]    [0023]FIG. 2 is a perspective view taken from the right front side of a damper with the blades shown in the opened position;  
         [0024]    [0024]FIG. 3 is a right side elevation of a damper as shown in FIG. 1;  
         [0025]    [0025]FIG. 4 is an enlarged view of a portion of the damper shown in FIG. 3 with electric parts show schematically;  
         [0026]    [0026]FIG. 5 is an enlarged top view of a portion of the damper as shown in FIGS. 1 through 4;  
         [0027]    [0027]FIG. 6 is an electrical schematic of a portion of the apparatus, as shown in the prior Figures with alternate positions shown in phantom lines;  
         [0028]    [0028]FIG. 7 is a side elevation of a damper in accordance with our invention as shown in the partially opened condition;  
         [0029]    [0029]FIG. 8 is a right side elevation of an apparatus in accordance with an alternate embodiment of our invention; and  
         [0030]    [0030]FIG. 9 is a schematic representation of a portion of the apparatus shown in FIG. 8.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0031]    In accordance with our invention, the damper comprises a frame  10 , having a plurality of blades  12  pivotally mounted therein for rotation between opened and closed positions. The actuator operating means comprises a motor  14  mounted to an extension  16  connected to the frame  10 . The motor operates a shaft  18 , FIG. 5, through a gear box  20 . The shaft extends from the hub  22  through the mounting plate  24 . A lever means is provided comprising a block  26  fixedly mounted to the end of the shaft and having fixedly mounted thereto one end, a lever arm  28  for rotation with the shaft. The other end of the lever arm  28  is pivotally connected to a further actuating arm  30  at  31 , FIG. 4. The other end of the lever arm  30  is pivotally connected to a blade bracket  34  at  32 , FIG. 3. Blade brackets  35  are connected to each blade and are interconnected for movement together by means of a link bar (not shown on the other side, in FIG. 3, but known in the art).  
         [0032]    By this arrangement, when the motor rotates the shaft  18 , the lever arms, link bars and bracket function to open and close the damper blades, as will be both fully described hereinafter.  
         [0033]    In the prior art, motors which were used for operating dampers typically had a travel of 90 degrees. In accordance with our invention, the motor has a travel of 180 degrees. This 180 degree travel allows us to use a smaller motor and it gives us more power for the same size damper.  
         [0034]    The motor is preferably a DC, that is direct current, motor and is connected to a circuit which permits reversing the polarity of the current to the motor. Reversing the polarity means that the motor can rotate either clockwise and counterclockwise depending on the polarity.  
         [0035]    Limit switch means for accomplishing the opening and closing of the damper comprises a plurality of micro switches and circuitry between the motor and the power source for interrupting the flow of electricity to the motor. The micro switch  40 , FIGS. 4 and 6, is mounted on a plate  16 , as shown. Micro switch  40  is actuated by an arm  42  which is made of a flexible material and is normally biased so as to be separated from engagement with the contact  44 . The micro switch is wired to the power supply  50  through wire  52  at its common terminal  54 . In a damper&#39;s open mode, current passes through this whole system in a clockwise direction when viewed as in FIG. 6. Thus, direct current passes in the direction of the arrow A from the power supply to the common terminal. In this initial operating condition, the power goes through the normally closed terminal  56  of micro switch  40 , to the motor  14  at contact  92 ; and then from the motor contact  90  through the normally closed terminal  84  of micro switch  80 ; and out through the common terminal  82  of micro switch  80  back to the power supply. Since current is flowing, the motor is running and will turn a maximum of 180 degrees; for example, from the position shown in phantom lines to the position shown in full lines. Engagement means for engaging the micro switch comprises a striker means carried by the lever  28 . Once the striker  70  reaches the arm  42  and depresses it so that the arm  42  makes contact with the contact  44 , this switches the micro switch internally from the position shown in solid lines in which it is connected to the normally closed terminal  56  to the normally open terminal  57  (as shown by the dotted lines). Since it switches to the normally open terminal  57 , the current will now flow from the power source  50  through the common terminal  54  to the normal open terminal  57 , and then to the diode  60 . However, the diode acts as a check valve and the current cannot get through. Therefore, the motor stops in that position.  
         [0036]    When the polarity of the power is switched, current flows in a counterclockwise direction. Thus, it flows from the power supply in the direction of the arrow B through the common terminal  82  of the micro switch  80  and out through the normally closed terminal  84  to the terminal  90  of the motor  14 . It then flows out through the terminal  92  of the motor and back up through the diode  60  to the normally open terminal  57  of the limit switch  40 . From there it travels internally through the common terminal  54  and back to the power source  50 . Thus, the motor  14  is once again activated and rotates 180 degrees in the other direction, moving the part  28  from the full line position shown in FIG. 6 to the phantom line position. As the striker  70  moves to that phantom position, it first engages the arm  102  and then depresses that arm  102  until the arm makes contact with the contact  104  of the limit switch  80 . When it makes that contact, the limit switch moves from the normally closed internal position at  84  to the normally open internal position at  86 . In that position, current flow is through the normally open terminal  86  to the diode  110 . However, the diode interferes with current flow and current flow cannot get through. Therefore, once again, the motor stops. Thus, the engagement means selectively engages one and another of the micro switches to operate them upon certain movements thereof.  
         [0037]    DC current can go in either direction in a circuit by reversing the polarity. But it only goes in one direction at a time; as compared to alternating current which goes in both directions.  
         [0038]    The diode acts as a check valve to the flow of electricity.  
         [0039]    The condition described above occurs when the motor rotates the shaft  18  and drives the lever arm  28  to move the striker  70  into contact with the flexible arms  42  and  102  and moves the arms so that they make electrical contact with the contacts on the micro switches. Thus, the micro switches are limit switches. With this lever arm  28  in the vertically upright position, as shown in FIG. 6, the damper is fully closed by the linkage mechanism. There, the limit switch  40  intercepts  20  the power to the motor and stops it. To open the damper, a switch means, be it a computer or a manual switch (not shown), changes the polarity of the DC current from the power supply  50 . That DC current now flows in the counterclockwise direction, when viewed as in FIG. 6, Arrow B.  
         [0040]    From what has been described, it will be appreciated that by placing a diode on each limit switch between the normally opened terminal and the normally closed terminal, it is possible to control the direction of flow through the circuitry.  
         [0041]    Current can bypass the limit switch because it goes through the diode and activates the DC motor to run in the opposite direction. This current flows for approximately two seconds. The switch is now shut and the current can flow freely through the switch.  
         [0042]    Referring to FIG. 7, it shows the damper in a partially opened position. This can be done by an additional power interrupt means comprising a switch mechanism (not shown), whether operated by computer or manually, to cut off the current from the power source  50 . Thus, the damper can be stopped anywhere in between the fully opened and fully closed positions. Therefore, one can modulate the damper.  
         [0043]    In this condition, the knee lock mechanism will not block the movement of the dampers in and of itself. However, this linkage, together with additional mechanical means comprising the motor, gears and, in the preferred embodiment, permanent magnets on the armature of the motor, will effectively prevent the damper from changing its position.  
         [0044]    In our prior co-pending application for a MULTI-BLADE MODULATING DAMPER WITH A CHAIN DRIVE, Provisional Application No. 60/293,639, filed May 26, 2001, the disclosure of which is incorporated herein by reference, the apparatus uses a sprocket gear and chain means as part of the actuator/operator mechanism in a damper to greatly increase the power of the operating mechanism, as well as eliminate the problems inherent in the prior art actuators having multiple gears in a train.  
         [0045]    It also provides a fully mechanically locked open and closure mechanism with no power needed to hold the damper in either position.  
         [0046]    This invention uses a Pittman or REX or equivalent DC motor designated generally  210  in FIG. 8, which has a series of spur gears within it.  
         [0047]    The device is further enhanced by use of a sprocket gear and chain drive means (designated generally  214 ) which comprises a sprocket  216  attached to the motor shaft to increase the gear ratio by driving a larger sprocket  218  attached to the operator shaft. In the prior art, the actuator had a gear train having five to ten gears in it; from a very small gear mounted on the motor shaft to the end gear mounted on the actuator shaft. That prior art device constantly stuck and failed. By eliminating these intermediate gears, we are able to obtain greatly enhanced power and reliable performance.  
         [0048]    In the preferred embodiment, we are able to obtain 500-inch pounds of force for opening the damper. The gear ratio of the sprocket/chain drive is steep enough to provide enough power to open the damper  212 , but not too steep to prevent back running, i.e., automatic closing of the damper under spring force. In particular, the gear ratio selected was 218 to 1 as being the most preferred.  
         [0049]    Another advantage of this invention is that with such a powerful configuration, it is possible to drive more than one damper off the same motor.  
         [0050]    Furthermore, because of the size of the motor, it can be placed easily within the duct, thereby protecting it in a fire situation.  
         [0051]    Also, because it is a DC motor, it does not hum when it is fully opened in the installed condition.  
         [0052]    In the development of this invention, it is noted that there was only a small window for operable conditions. If the gear ratio was too low, it would not open the damper and if the gear ratio was too steep, it would back run. From our experience, the gear ratio can run from a minimum of 195 to a maximum of 218.  
         [0053]    Operation:  
         [0054]    Referring to FIGS. 8 and 9, the power comes on to energize the motor  210 . The energy comes through a limit switch  300  back to the motor to open the damper. The damper, in turn, opens until the limit switch is reached. Once the limit switch is reached, current is switched from going directly back to the motor from the limit switch to a resister  310 . The resister is a 100M resister and it cuts the voltage from 21 volts down to 2 volts; which is enough to hold the damper in open position and not allow the spring return, but it is such a small amount of current that it will not break anything. When power is removed from the whole system, the mechanism springs shut to return the damper to its closed position.  
         [0055]    A mechanism for utilizing both a chain drive and an over center linkage is disclosed in our prior co-pending application for a CHAIN OPERATOR DRIVE FOR A BUTTERFLY DAMPER WITH A DOUBLE ACTING OVER CENTER LOCK, provisional application No. 60/293,656, filed May 25, 2001, the disclosure of which is incorporated herein by reference.  
         [0056]    As shown in FIG. 5 thereof, the device was designed such that at its uppermost and lowermost points, the cross-shaft through the sprocket gear, in both the open and the closed positions, is over center of the plane of the center line of the shaft by preferably {fraction (2/10)}ths of an inch.  
         [0057]    This creates what is known as a double acting over center or knee lock. Thus, no matter how much pressure is put upon the blades, they cannot be forced open or closed.  
         [0058]    In a fire situation where firemen would be using hoses to force water under high pressure on to the dampers, water could hit the blades of the damper and force them to open or shut. This may not be the optimal condition at the time. An advantage to this type of device is that in such a situation, the blades will not open or close in response to the force of the water.  
         [0059]    In the present invention, the actuating means comprises an arrangement of arms such that the two pivot points go over center in both the open and closed position with 180 degrees rotation of the lever arm  28 . This over center arrangement provides a knee lock in both the open and closed positions.  
         [0060]    The functioning of this knee lock can be appreciated from viewing FIGS. 2, 3 and  7 . Suppose, for example, there was an external force being applied to the damper from one side, as shown by the Arrow C in FIG. 3. That force would tend to be exerted on the pivot point  32  in the direction of the Arrow D. This force would then be translated through the lever  30  and attempt to force the pivot point  31  to move in the direction of the Arrow E. But that would not be possible because the motor has already run to its limit of 180 degrees of travel. The pivot point  31  is now over center of the axis of the shaft  18  (represented diagrammatically by the center line designated CL).  
         [0061]    When the damper is partially open, as shown in FIG. 7, the pivot point  32  tends to move in the direction of the Arrow D and the arms  30  and  28  are pivoted with respect to one another about the pivot point  31 , as shown by the Arrow R.  
         [0062]    Opening continues until the fully opened position, such as shown in FIG. 2, wherein the pivot point  31  is on the other side of the center line CL.  
         [0063]    Any force trying to exert a force to close the damper by impinging upon the damper blades, would tend to direct the pivot point  32  upwardly in the direction of the Arrow F in FIG. 2. In this condition, the pivot point  31  would tend to try to move in the direction of the Arrow G. However, it cannot do that because the motor has gone 180 degrees to its maximum position, as shown in that Figure.