Abstract:
The present invention is a method and apparatus for driving a roller-shutter door having a drive mechanism. The method comprises the activation of a circuit in response to an external stimuli to a switch. This actuates a timer and raises a timing bar. A cable passes across the timing bar and is connected to the switch on one end and to a solenoid on a second end. The cable passes through a top portion of a rocker arm assembly having a one-way bearing. The solenoid is actuated as a result of the raising of the timing bar; and activates the one-way bearing to cause the door to be raised to a pre-set position for a pre-set period of time. To reverse the door, the timer bar is dropped after the lapse of the pre-set period of time. The solenoid is re-activated and reverses the one-way bearing.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method and apparatus for driving roller shutter doors to a closed or open state. More specifically, the present invention relates to a controller for applying motive power to a roller shutter door of the type used to retard passage in the event of fire, smoke or similar conditions, or, of doors simply used to prevent egress or entrance based on the time of day or the opening or closing of the facility to which the door is a portal. 
     2. Description of the Related Art 
     Roller shutter doors have been known for some time and are used in a variety of applications. They include such categories as: rolling grille; storm doors; fire and smoke doors; air-leakage doors, counter shutters; and, the like. What they have in common is a construction that allows them to be rolled up onto a drum or tube when in the open position; or, to be unreeled from the drum when the door is being lowered. Theses doors are typically used in commercial establishments to seal or close off large doorways, or bays, and can be operated electrically, manually, or both. 
     The methods and systems for driving the doors into an upward or downward position, during normal or emergency operation, have evolved over time from simple pull down doors of a kind used in residential garages, to more technologically advanced electric drive systems with timers, manual over-rides, and diverse safety features. 
     Generally, commercial or large capacity fire doors were driven by electric motors to open or close the door. However, when a fire occurred, these mechanisms would disengage the motor from the fire door and allow the door to close under the pressure exerted by an auxiliary spring activated by mechanical means or from a counterbalance. These mechanical means included pendulums, oscillating governors, friction discs, ratchets, etc. These mechanical devices tended to be unreliable because of jamming or other malfunctions caused by the motion of the door. One early mechanism that attempted to address this problem was described in U.S. Pat. No. 5,203,392 for a Mechanism For Controlling The Raising And Lowering Of A Door, issued Apr. 20, 1993 to Shea (hereinafter referred to as “Shea”). 
     In Shea, there is disclosed a mechanism for controlling the opening and closing of a door such as a fire door. The mechanism controls the speed of the door when it drops under the force of gravity; and, can be electrically, or manually, operated. The problem that Shea was attempting to address was the need for a fire door mechanism that regulates the raising and lowering of the door while effectively controlling the door&#39;s movement without the need of springs or similar mechanical means. The speed of the door&#39;s drop was under control of a centrifugal governor employing brake shoes. 
     Other prior art has addressed the need for testing the speed and effects of the door&#39;s drop during non-emergency uses. U.S. Pat. No. 5,482,103 for a Door Apparatus With Release Assembly, issued Jan. 9, 1996 to Burgess et al. (hereinafter referred to as “Burgess”) teaches the use of a counterweight to offset the weight of the roller door and a reducing weight to reduce the weight of the counterweight. The assembly of the door allows the use of a standard governor to control downward speed. This use of reduced weight and the resultant reduced stress on the door allows the mechanism to use parts that are reduced in size and weight. 
     After the disclosures of Shea and Burgess, came the teachings of U.S. Pat. No. 5,924,949 for an Apparatus For Driving A Roller Shutter Door, issued Jul. 20, 1999 to Fan (hereinafter referred to as “Fan”). Fan teaches a driving mechanism for roller shutter doors that can be adjusted from outside of the apparatus so as to accommodate doors of different heights. The advantage of Fan is that the mechanism, if either moved from a door of one height to a door of a differing height, or if the door is not of the height for which the factory settings apply, does not have to be disassembled for adjustments. Rather, the adjustable control means is disposed within the stationary housing of the apparatus, and extends from within the apparatus to a point outside where it can be manipulated or adjusted as required. And, while Fan addresses a legitimate need, it still leaves unanswered the need to allow the door to move freely into an open position while under control of a governor. 
     Further improvements to the drive mechanism are taught in U.S. Pat. No. 6,530,863 for a Door Operator Unit, issued Mar. 11, 2003 to Balli et al. (hereinafter referred to as “Balli”). In Balli, an improved power transmission mechanism which works between the drive motor and the operator output shaft is disclosed. The operator unit is adapted to reverse the positions of a manual operator drive and a release mechanism. The advantage provided by Balli is the ability to interchange the operator unit components depending upon the door configuration or application. Thus, the drive mechanism can be established as either a right side or a left side mount. Balli still leaves the question of door control after rebounding, or the issue of timer adjusted openings and closings to be addressed. 
     The evolution of the rollup door and its drivers and safety mechanisms has continued with the disclosures of U.S. Pat. No. 7,261,139 for a Manual Operating Mechanism For Upward Acting Door, issued Aug. 28, 2007 to Varley et al. Varley teaches a mechanism that addresses the difficulty of operating a roll-up door manually in those cases where the drive motor is mounted in an assembly that is beyond the easy reach of the user. The mechanism of Varley includes a manual brake release that is foot actuated by a person using an elongated crank handle to manually move the door from an open to closed position or vice versa. A problem left unanswered by Varley is how an operator, under the stress of an emergency, can efficiently disengage the motor drive. 
     What is not appreciated by the prior art is the need to provide a method and apparatus for controlling the drop of the door (or curtain as the case may be) that incorporates each of the successes of the prior art while minimizing the problems. One important issue not addressed by the prior art, is that the drop of the door should be controlled by a mechanical centrifugal governor such that the door does not “bounce” after it arrives in the full open position. While in a closed position, the curtain or door must be able to maintain its locked position unless the door or curtain is manually released through the use of a manual lever and/or an electrical switch. The use of a timer to allow the door to re-open at least part-way, and then close after a specific time interval during an emergency, would provide a safety that is currently lacking in the art. 
     Accordingly, there is a need for an improved method and apparatus that will supply multiple safety features in the event of an emergency while providing for more efficient operation of the door during normal use. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a mechanism for driving a roller-shutter door that can be operated in an emergency by hand push-up, manual chain drive, or by motor power. 
     Another aspect of the present invention is to provide a mechanism for driving a roller-shutter door in response to elevated, unsafe or emergency levels of wind, smoke or fire that are communicated to the mechanism through a sensor coupled to an electrical control mechanism. 
     An object of the present invention is to provide a mechanism for driving a roller-shutter door that can be operated simply as an egress mechanism when utilized with non fire-rated door applications, thus allowing for emergency egress on standard doors. 
     The present invention relates to a method and apparatus for driving a roller-shutter door having a drive mechanism. The method comprises the activation of a circuit in response to any one of several external stimuli (such as a smoke detector alarm) to a switch for activating the door&#39;s drive mechanism and/or directional movement. This, in turn, actuates a timer and raises a timer arm. A cable passes across the timing arm and is connected to the switch on one end, and to a solenoid on a second end. The cable passes through a top portion of a rocker arm assembly having a one-way bearing. The solenoid is actuated as a result of the raising of the timing arm; and, activates the one-way bearing to cause the door to be raised to a pre-set position for a pre-set period of time. To reverse the door, the timer arm is dropped after the lapse of the pre-set period of time. The solenoid is re-activated and reverses the one-way bearing. 
     According to an embodiment of the present invention, there is provided a method and apparatus for driving a roller-shutter door having a drive mechanism. The method of the present invention comprises a number of steps beginning with the activation of a circuit in response to an external stimulus (such as a smoke detector alarm) to a switch. The switch can be located in any one of several of locations depending upon design choice or specific environmental requirements. For instance, it can be located on an outer wall of a building supporting the roller shutter door; and wherein the switch is within a break-glass station. 
     The external stimuli is the closing of a circuit linked to a sensor for measuring an anomaly, such as: an elevated smoke level, excessive heat (caused by a fire or the like), or simply the passage of time as determined by a real time clock. 
     The activation of the circuit actuates a timer and which in turn raises a timing arm of the timer. A cable passes across a top portion of the timing arm and is connected to the switch on one end and to a solenoid on a second end. The cable passes through a top portion of a rocker arm assembly disposed between the timer and the solenoid; and, wherein the rocker arm assembly comprises a one-way bearing. The solenoid is actuated as a result of the raising of the timing arm; and activates the one-way bearing to cause the door to be raised to a pre-set position for a pre-set period of time under control of the timer and as driven by the drive mechanism. 
     In reversing the movement of the door, the method further comprises utilizing the timer for a pre-set period of time; and, wherein the timer bar is dropped after the lapse of the pre-set period of time. The solenoid is re-activated in response to the dropping of the timer bar, and reverses the one-way bearing in response to the actuation of the solenoid. The door is then dropped to a closed position in response to the reversing of the one-way bearing. The dropping of the door is caused by gravity; and, the speed of the dropping of the door is under control of a centrifugal speed governor. 
     The drive mechanism itself for opening or closing the roller-shutter door comprises a number of key elements. The elements include a drive plate having a centrally located hub, and wherein the hub has a geared portion located on the outside surface thereof. There is also a drive gearset having a geared hub mounted coaxially about the central hub of the drive plate; and, a second gear having a geared hub and mounted coaxially about the geared hub of the drive gearset. In addition, there is a stationary housing adapted to accommodate the drive gearset and the drive plate. A motor located externally to the stationary housing for driving the second gear, and control means disposed within the stationary housing and in meshed contact with the central hub for controlling actuation of the motor in response to an external stimuli, and whereby the roller shutter door can be moved to a predetermined limit position are also provided. The drive mechanism also an adjustable gearset that is accessible from outside the stationary housing. Additionally, the drive mechanism comprises the rocker arm assembly and centrifugal speed governor previously noted. 
     In an alternative embodiment of the present invention, a stepper motor is used in place of the solenoid. When using the solenoid, the method comprises the activation of a circuit in response to any one of several external stimuli (such as a smoke detector alarm) to a switch for activating the door&#39;s drive mechanism and/or directional movement. This, in turn, actuates a timer and raises a timer arm. A cable passes across the timing arm and is connected to the switch on one end, and to a stepper on a second end. The cable passes through a top portion of a rocker arm assembly having a one-way bearing. The stepper is actuated as a result of the raising of the timing arm; and, rotates its shaft to cause the door to be raised to a pre-set position for a pre-set period of time. To reverse the door, the timer arm is dropped after the lapse of the pre-set period of time. The stepper motor is re-activated and completes a turn of the shaft to reverse the one-way bearing. 
     In another embodiment of the present invention, the doors are driven horizontally (relative to the door&#39;s threshold) from opposing directions so that they meet in the middle of the threshold. The drive mechanism is the same as that provided for the vertical (up or down) movement of the door, except that the drive is biased horizontally instead of laterally. 
     The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conduction with the accompanying drawings, in which like reference numerals designate the same elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of a curtain or roller door having a hand chain drive, shown when the door is in the open position. 
         FIG. 2  is an elevation view of a hand chain drive embodiment of the present invention showing the top of the drive chain housing. 
         FIG. 3  is an isometric view of the hand chain drive embodiment of the present invention showing the timer, solenoid, rocker arm assembly, and governor. 
         FIG. 4  is an isometric view of a curtain or roller door having a motorized chain drive, shown when the door is in the open position. 
         FIG. 5  is an elevation view of the chain drive embodiment of the present invention showing the top of the motor mount housing. 
         FIG. 6  is an isometric view of a motorized chain drive embodiment of the present invention showing the timer, solenoid, rocker arm assembly, and governor. 
         FIG. 7  is an isometric view of a curtain or roller door having a 24 v motor drive wherein the door is in the open position. 
         FIG. 8  an elevation view of the 24 volt motor drive embodiment of the present invention showing the side of the motor mount housing. 
         FIG. 9  is an isometric view of the 24 volt motor embodiment of the present invention showing the timer, solenoid, rocker arm assembly, and governor. 
         FIG. 10A  is an exploded view of the rocker arm components of the rocker arm. 
         FIG. 10B  is an exploded view of the centrifugal governor components of the governor. 
         FIG. 11  is an elevation view of the embodiment of the interior of the gear box of the present invention. 
         FIG. 12  is an exploded view of the embodiment of the interior of the gear box of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to several embodiments of the invention that are illustrated in the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. For purposes of convenience and clarity only, directional terms, such as top, bottom, up, down, over, above, and below may be used with respect to the drawings. These and similar directional terms should not be construed to limit the scope of the invention in any manner. The words “connect,” “couple,” and similar terms with their inflectional morphemes do not necessarily denote direct and immediate connections, but also include connections through mediate elements or devices. 
       FIGS. 1-9  are general overviews of the present invention which illustrate the placement of the mechanism relative to the roll-up door to be driven. It is within the scope and teachings of the present invention that the placement of the mechanism can be either on the right side or the left side, of the housing for the roller drum of the door. Indeed, the mechanism is designed in such a way as to provide easy left or right side adjustment. 
     Turning to  FIG. 1 , there is shown an isometric view of the system  50  of the claimed invention having a curtain or rolling door  9  having a hand chain drive  13  wherein the rolling door  9  is in the open position relative to the doorway of wall section  5 . When rolled up under the control of the hand chain drive  13  of the mechanism  11 , the rolling door  9  is wrapped around a drum (not shown) that runs the length of a housing  7 . 
     The rolling door  9  is lowered or raised, as the case may be, by a user pulling on chain  13 . The movement of the various components is described in more detail with respect to  FIG. 3 . The advantage of the current design is the ability to retrofit any of the primary embodiments to existing door drive systems or to upgrade from one embodiment to another. Further, the mechanism allows for driving a rolling door that can be operated simply as an egress mechanism when utilized with non fire-rated door applications, thus allowing for emergency egress on standard doors. 
     For a depth perspective, as to placement and fitting of components, we turn to  FIG. 2  where there is shown an elevation view of the hand chain drive embodiment of the present invention showing the side wall of the drive chain housing. 
     Hand chain drive  19  is shown wherein pulling of the chain turns a shaft (view blocked by the pulley and shaft housing wall) which in turn rotates a gear (not shown in this perspective). The gear moves chain  29  which is connected to a gear on the main gear shaft  31 . A chain  21  links main gear shaft  31  with adjusting post  33  and is covered by a plate  17 . The main gear shafts  31 ,  33  drive the interior mechanism of the gearbox  35  (described in more detail with respect to  FIGS. 11 and 12 ), rotating drive gear  27 , that causes the rolling door  9  to be rolled up or down. The speed of the roll up is governed by the governor not shown, and measured by the rocker arm  23  through the rotation of rocker arm gear  15 . Actuation of the rocker arm  23  for upward or downward movement of the rolling door  9  comes from the in or out action of solenoid  25  under control of the timing switch (not shown). 
       FIG. 3  is an isometric view of the hand chain drive embodiment of the present invention showing the timer  114 , solenoid  118 , rocker arm assembly  122 , and the speed governor  125 . 
     The hand drive embodiment receives its drive power from the chain  100  being pulled by a mechanism user. The chain rotates pulley  101  which turns gear  102 . In turn, gear  102  causes chain  104  to move which drives main gear shaft  108 . Main gear shaft  108  supports one end of a chain (not shown) which is covered and protected by plate  106 . The other end of the protected chain drives main gear shaft  110 . The movement of the main gear shafts causes the inner workings (as shown and described in  FIGS. 11 and 12 ) of the gearbox  111  to rotate drive gear  124 . Drive gear  124  rotates an inner shaft which causes the shaft to take up or release door  9  which is wound or unwound from a drum in housing  7 . The directionality of the rotation up or down is controlled by the one-way bearing of the rocker arm assembly  122 . 
     There is shown the rocker arm components of the rocker arm  122  as secured just past the 12:00 o&#39;clock position relative to the top of the drive gear  124 . Gear  120  is secured to rocker arm body  122  with a one-way bearing (not shown) disposed therebetween. Bracket attachment assembly  123  is used to secure the lower portion of rocker arm body  122  while allowing it to pivot when activated so as to engage the gear  120  with the drive gear  124  to control speed under the directional control of the pivoting one-way bearings. Cable holder  116  is secured between the upper portions of the swing bodies  117  so as to hold the cable  113  which links the solenoid  118  and timer switch  114 . The cable is under direction of an emergency back up which causes the timer switch  112  to be set so as to position arm  114  in such a way as to elevate the chain  113  causing the solenoid  118  to be activated which pivots the rocker arm  122  to engage opposite directional, one-way bearing  200 . As the timer reaches its “timed out” position, the arm  114  is dropped, causing the solenoid to open, which in turn pivots rocker arm  122  to engage the one-way bearing  200  so that the rolling door  9  will close. 
     Alternatively, a stepper motor is used in place of the solenoid  118 . When using the stepper motor, the motor is activated which pivots the rocker arm  122  to engage opposite directional, one way bearing  200 . As the timer reaches its “timed out” position, the timer switch  114  is dropped, causing the stepper motor to turn “a step”, which in turn pivots rocker arm  122  to engage the one-way bearing  200  so that the rolling door  9  will close. To reverse the door, the timer switch  114  is dropped after the lapse of the pre-set period of time. The stepper motor is re-activated and completes a turn of the shaft to reverse the one-way bearing. 
     Alternatively, the doors are driven horizontally (relative to the door&#39;s threshold) from opposing directions so that they meet in the middle of the threshold. The drive mechanism is the same as that provided for the vertical (up or down) movement of the door, except that the drive is biased horizontally instead of laterally. 
     The speed of the door&#39;s descent is extremely important in that too great a speed will cause the door to hit the full down position and bounce and be in the wrong position, or cause strain on the mechanism. To avoid these problems, the mechanism utilizes a centrifugal speed governor. 
     A view of the centrifugal speed governor  125 , and its components, is shown wherein the governor  125  is shown as secured between the 10:00 and 11:00 o&#39;clock position relative to the top of the drive gear  124  (its position could change if the mechanism becomes “right-handed”). Clutch weights  126 ,  126  are slot mounted on the upper portion of the rotor body assembly cap  128 . Clutch pad  130  for braking is secured between the rotor body assembly cap  128  and the fixed rotor  140 . Cap  128 , clutch pad  130 , and fixed rotor  140  are combined to form the rotor body assembly. 
     The rotor body assembly is transected in the center by shaft  132  which supports the rotor body assembly on one end and the governor gear  142  on the opposite end. The gear  142  is in mated contact with the system&#39;s main drive gear  124  so as to control the speed of the door  9 . The gear  142  bisects the supports  134  which are perpendicular (90 degrees) to each other and welded to the bracket  201 . 
     When activated, the governor  125  rotates to a certain speed, when that speed is increased beyond the threshold speed, slot mounted weights  126  are pulled apart by centrifugal force which causes pressure on the clutch pad  130 , causing the governor  125  to brake the speed of the door&#39;s descent. 
       FIG. 4  is an isometric view of a curtain or rolling door  9  having a chain drive wherein the door is in the open position. 
     Turning to  FIG. 4 , there is shown an isometric view of the system  250  of the claimed invention having a curtain or rolling door  9  and having a motorized chain drive  211  wherein the door  9  is in the open position relative to the doorway of wall section  205 . When rolled up under the control of the chain drive of the mechanism  211 , the rolling door  9  is wrapped around a drum (not shown) that runs the length of housing  207 . 
     The rolling door  9  is lowered or raised, as the case may be, by the electrical activation of a motor which drives the chain. The movement of the various components is described in more detail with respect to  FIG. 6 . The advantage of the current design is the ability to retrofit any of the primary embodiments to existing door drive systems or to upgrade from one embodiment to another. 
       FIG. 5  is an elevation view of the chain drive embodiment of the present invention showing the top of the motor mount housing. 
     Chain drive  319  is shown where the chain drive  319  under control of a motor, contained within the chain drive housing  319 , rotates a shaft which in turn rotates a gear (not shown in this perspective). The gear moves chain  321  which is connected to the main gear shafts which are connected with a chain therebetween (not shown). The main gear shafts, in turn, drive the interior mechanism of the gearbox  335  (described in more detail with respect to  FIGS. 11 and 12 ), rotating drive gear  327 , that causes the door  9  to be rolled up or down. The speed of the roll up is governed by the governor not shown, and measured by the rocker arm  323  through the rotation of rocker arm gear  315 . Actuation of the rocker arm  323  for upward or downward movement of the rolling door  9  comes from the in or out action of solenoid  325  under control of the timing switch (not shown). 
       FIG. 6  is an isometric view of the chain drive embodiment of the present invention showing the timer  412 , solenoid  418 , rocker arm assembly  422 , and the centrifugal speed governor  425 . 
     The chain drive embodiment receives its drive power from the motor driven chain  401  being driven by motor  400  which is preferably a 24 volt DC motor which can be battery backed if necessary or desired. The mechanism and operator drive can be separated, where the mechanism will work in conjunction with external operators for larger size doors that require higher voltage units, where the operator needs a minimum of 110 volt, thru 575 volts. The motor turns gear  404  which moves chain  406 . In turn, gear  404  causes chain  406  to move which drives main gear shaft  408 . Main gear shaft  408  supports one end of a chain (not shown) which is covered and protected by plate  407 . The other end of the protected chain drives main gear shaft  410 . The movement of the main gear shafts  408 ,  410  causes the inner workings (as shown and described in  FIGS. 11 and 12 ) of the gearbox  411  to rotate drive gear  424 . Drive gear  424  rotates an inner shaft which causes the shaft to take up or release door  9  which is wound or unwound from a drum in housing  7 . The directionality of the rotation up or down is controlled by the pivoting of the one-way bearing of the rocker arm assembly. 
     There is shown the rocker arm components of the rocker arm  422  as secured just past the 12:00 o&#39;clock position relative to the top of the drive gear  424 . Gear  420  is secured to rocker arm body  422  with a one-way bearing (not shown) disposed therebetween. Bracket attachment assembly  423  is used to secure the lower portion of rocker arm body  422  while allowing it to pivot between one way bearing gear  200  when activated so as to engage the gear  420  with the drive gear  424  to control speed under the directional control of the one-way bearings  200 ,  420 . Cable holder  416  is secured between the upper portions of the swing bodies  417  so as to hold the cable  413  which links the solenoid  418  and timer switch  414 . The cable is under direction of an emergency back up which causes the timer switch  412  to be set so as to position timer switch  414  in such a way as to elevate the cable  413  causing the solenoid  418  to be activated which pivots the one-way bearing  420  of the rocker arm to the other one way bearing  200 . As the timer reaches its “timed out” position, the rocker arm  422  is dropped, causing the solenoid  418  to open which in turn pivots to the other one-way bearing so that the door  9  will close. 
     Alternatively, a stepper motor is used in place of the solenoid  418 . When using the stepper motor, the motor is activated which pivots the rocker arm  422  to engage opposite directional, one-way bearing  200 . As the timer reaches its “timed out” position, the timer switch  414  is dropped, causing the stepper motor to turn “a step”, which in turn pivots rocker arm  422  to engage the one-way bearing  200  so that the rolling door  9  will close. To reverse the door, the timer arm is dropped after the lapse of the pre-set period of time. The stepper motor is re-activated and completes a turn of the shaft to reverse the one-way bearing. 
     Alternatively, the doors are driven horizontally (relative to the door&#39;s threshold) from opposing directions so that they meet in the middle of the threshold. The drive mechanism is the same as that provided for the vertical (up or down) movement of the door, except that the drive is biased horizontally instead of laterally. 
     The speed of the door&#39;s descent is extremely important in that too great a speed will cause the door to hit the full down position and bounce and be in the wrong position, or cause strain on the mechanism. To avoid these problems, the mechanism utilizes a centrifugal speed governor. 
     A view of the centrifugal speed governor  425 , and its components, is shown wherein the governor  425  is shown as secured between the 10:00 and 11:00 o&#39;clock positions relative to the top of the drive gear  424  (its position will be opposite if the mechanism becomes “right-handed”). Clutch weights  426 ,  426  are slot mounted on the upper portion of the rotor body assembly cap  428 . Clutch pad  430  for braking is secured between the rotor body assembly cap  428  and the fixed rotor  440 . Cap  428 , clutch pad  430 , and fixed rotor  440  are combined to form the rotor body assembly. 
     The rotor body assembly is transected in the center by shaft  432  which supports the rotor body assembly on one end and the governor gear  442  on the opposite end. The gear  442  is in mated contact with the system&#39;s main drive gear  424  so as to control the speed of the door  9 . The gear  442  bisects the supports  434  which are perpendicular to each other and welded to the bracket  201 . 
     When activated, the governor  425  rotates to a certain speed, when that speed is increased beyond the threshold speed, slot mounted weights  426  are pulled apart by centrifugal force which causes pressure on the clutch pad  430 , causing the governor  425  to brake the speed of the door&#39;s descent. 
       FIG. 7  is an isometric view of a curtain or rolling door having a 24 v motor drive wherein the door is in the open position. 
     Turning to  FIG. 7 , there is shown an isometric view of the system  550  of the claimed invention having a curtain or roller door  9  and having a motor drive wherein the door  9  is in the open position relative to the doorway of wall section  505 . When rolled up under the control of the motor drive of the mechanism  511 , the door  9  is wrapped around a drum  515  that runs the length of the interior of housing  207 . 
     The door  9  is lowered or raised, as the case may be, by the electrical activation of a motor which directly drives the inner workings of the gear box to drive the drive gear. The movement of the various components is described in more detail with respect to  FIG. 9 . The advantage of the current design is the ability to retrofit any of the primary embodiments to existing door drive systems or to upgrade from one embodiment to another. 
       FIG. 8  an elevation view of the 24 volt motor drive embodiment of the present invention showing the side of the motor mount housing. 
     Motor drive  519  is shown to drive a gear and worm gear assembly  521 , contained within the motor drive housing  519 , rotates a shaft which in turn rotates a gear (not shown in this perspective). The gear moves drives the drive gear  523  in accordance with the description of  FIGS. 11 and 12  herein. The rotating drive gear  523  causes the door  9  to be rolled up or down. The speed of the roll up is governed by the governor not shown, and measured by the rocker arm  525  through the rotation of rocker arm gear  527 . Actuation of the rocker arm  525  for upward or downward movement of the door  9  comes from the in or out action of solenoid  529  under control of the timing switch (not shown). 
       FIG. 9  is an isometric view of the 24 volt motor embodiment of the present invention showing the timer  578 , solenoid  586 , rocker arm assembly  592 , and the centrifugal speed governor  565 . 
     The motor embodiment receives its drive power from the motor  560  mounted directly until the gearbox  595 . The motor  560  is preferably a 24 volt DC motor which can be battery backed if necessary, or desired; however, for driving heavier loads or peripheral features, a 100 volt motor may be advantageous. Its only drawbacks will be weight and the ineffectiveness of using battery back-up for the high power draw device. 
     The motor  560  turns the inner workings (as shown and described in  FIGS. 11 and 12 ) of the gearbox  595  to rotate drive gear  597 . Drive gear  597  rotates an inner shaft which causes the shaft to take up or release door  9  which is wound or unwound from a drum in housing  7 . The directionality of the rotation up or down is controlled by the pivoting of the one way bearings of the rocker arm assembly. Adjusting posts  562  allow for system adjustment of the timing of the internal gears of the gearbox without having to remove the mechanism from the doorway, or to open up the gearbox for simple adjustments. 
     There is shown the rocker arm components of the rocker arm  592  as secured just past the 12:00 o&#39;clock position relative to the top of the drive gear  597 . Gears  590 ,  200  are secured to rocker arm body  592  with a one-way bearing (not shown) disposed therebetween. Bracket attachment assembly  588  is used to secure the lower portion of rocker arm body  592  while allowing it to pivot when activated so as to engage the gear  590 , or the gear  200 , with the drive gear  597  to control speed under the directional control of the one-way bearings. Cable holder  582  is secured between the upper portions of the swing bodies  584  so as to hold the cable  577  which links the solenoid  586  and timer switch  578 . The cable  577  is under direction of an emergency back up which causes the timer switch  578  to be set so as to position timer switch  580  in such a way as to elevate the cable  577  causing the solenoid  586  to be activated which pivots the rocker arm from one one-way bearing to the other one-way bearing. As the timer reaches its “timed out” position, the timer switch  580  is dropped, causing the solenoid  586  to open which in turn pivots the rocker arm  592  from one one-way bearing to the other one-way bearing so that the door  9  will close. 
     Alternatively, a stepper motor is used in place of the solenoid  586 . When using the stepper motor, the motor is activated which pivots the rocker arm  422  to engage opposite directional, one-way bearing  200 . As the timer reaches its “timed out” position, the timer switch  580  is dropped, causing the stepper motor to turn “a step”, which in turn pivots rocker arm  592  to engage the one-way bearing  200  so that the rolling door  9  will close. To reverse the door, the timer switch  580  is dropped after the lapse of the pre-set period of time. The stepper motor is re-activated and completes a turn of the shaft to reverse the one-way bearing. 
     Alternatively, the doors are driven horizontally (relative to the door&#39;s threshold) from opposing directions so that they meet in the middle of the threshold. The drive mechanism is the same as that provided for the vertical (up or down) movement of the door, except that the drive is biased horizontally instead of laterally. 
     The speed of the door&#39;s descent is extremely important in that too great a speed will cause the door to hit the full down position and bounce and be in the wrong position, or cause strain on the mechanism. To avoid these problems, the mechanism utilizes a centrifugal speed governor. 
     A view of the centrifugal speed governor  565 , and its components, is shown wherein the governor  565  is shown as secured between the 2:00 and 3:00 o&#39;clock position relative to the top of the drive gear  597  (its position could change if the mechanism becomes “right-handed”). Clutch weights  566 ,  566  are slot mounted on the upper portion of the rotor body assembly cap  568 . Clutch pad  570  for braking is secured between the rotor body assembly cap  568  and the fixed rotor  572 . Cap  568 , clutch pad  570 , and fixed rotor  572  are combined to form the rotor body assembly. 
     The rotor body assembly is transected in the center by shaft  576  which supports the rotor body assembly on one end and the governor gear  574  on the opposite end. The gear  574  is in mated contact with the system&#39;s main drive gear  597  so as to control the speed of the door  9 . The gear  574  bisects the supports  575 ,  575  which are perpendicular (90 degrees) to each other and welded to the bracket  201 . 
     When activated, the governor  565  rotates to a certain speed, when that speed is increased beyond the threshold speed, slot mounted weights  566  are pulled apart by centrifugal force which causes pressure on the clutch pad  570 , causing the governor  565  to brake the speed of the door&#39;s descent. 
       FIG. 10A  is an exploded view of the rocker arm components of the rocker arm  620  as secured just past the 12:00 o&#39;clock position relative to the top of the drive gear as is shown in  FIG. 9 . Gear  600 ,  600  is secured to rocker arm body  603  with one-way bearings  601 ,  601  disposed therebetween. Bracket attachment assembly  602  is used to secure the lower portion of rocker arm body  603  while allowing it to pivot when activated so as to pivot between directional bearings gears and the drive gear to control speed under the directional control of the one-way bearings  601 ,  601 . Brass washers  604  provide spacing for the fixed shaft  605  which joins brass swing bodies  607  to the rocker arm body  602  on opposite sides of the upper portion of the rocker arm body  608 , which allows the upper portion of the rocker arm body  608  to pivot so as to engage either one of the directional bearing gears. Cable holder  606  is secured between the upper portions of the brass swing bodies  607  so as to hold the cable which links the solenoid and timer switch (see  FIG. 3 ). 
     Turning next to  FIG. 10B , there is shown an exploded view of the centrifugal governor components of the governor  650  as secured between the 2:00 and 3:00 o&#39;clock positions relative to the top of the drive gear as is shown in  FIG. 9 . Clutch weights  625  are slot mounted on the upper portion of the rotor body assembly cap  626 . Clutch pad  627  for braking is secured between the rotor body assembly cap  626  and the fixed rotor  628 . Cap  626 , clutch pad  627 , and fixed rotor  628  are combined to form the rotor body assembly. 
     The rotor body assembly is transected in the center by shaft  630  which supports the rotor body assembly on one end and the governor gear  633  on the opposite end. The gear  633  is in mated contact with the system&#39;s main drive gear so as to control the speed of the door. The gear bisects the supports  634  which are perpendicular (90 degrees) to each other and welded to the bracket of the surface mount. A set of top bearings  631  and bottom bearings  632  are supported by the bearing cover sleeves  629 ,  629  respectively which are in turn supported by the shaft and located on opposite sides of the gear  633 . 
     When activated, the governor  650  rotates to a certain speed, when that speed is increased beyond the threshold speed, slot mounted weights  625  are pulled apart by centrifugal force which causes pressure on the clutch pad  627 , causing the governor  650  to brake the speed of the door&#39;s descent. 
     The internal workings of the system are best understood by reference to  FIG. 11  and  FIG. 12 . 
       FIG. 11  is a plan view of the embodiment of the interior of the present invention; and,  FIG. 12  is an exploded view of the embodiment of the interior of the gear box of the present invention. Together, the two FIGs. describe the gearbox for the present invention. 
     As is shown in  FIG. 11 , two adjustable control means, each of which includes a timing gearset  760 , an adjusting gearset  770  and a micro-switch  754 , are mounted in the stationary housing  750 . The timing gearset  760  includes a first timing gear  761  and a second timing gear  762  as are shown in  FIG. 12 . The first timing gear  761  has a first recessed surface  811  defined thereon. The second timing gear  762  has a second recessed surface  821  defined thereon. The first timing gear  761  and the second timing gear  762  have a same pitch number (diametral pitch) and a same pitch diameter, but have different tooth numbers. 
     The first timing gear  761  and the second timing gear  762  are coaxially mounted in the stationary housing  750 . The first recessed surface  811  of the first timing gear  761  is arranged to face the second recessed surface  821  of the second timing gear  762  and the two recessed surfaces  811  and  821  are offset by a predetermined angle in the beginning. Since the tooth number of the first timing gear  761  is different from the tooth number of the second timing gear  762 , the first recessed surface  811  of the first timing gear  761  and the second recessed surface  821  of the second timing gear  762  can coincide with each other when the first timing gear  761  and the second timing gear  762  are rotated, which depends on the difference of the tooth number between the two timing gears. 
     The adjusting gearset  770  (as shown in  FIG. 11 ) includes a first adjusting gear  771 , a second adjusting gear  772 , an adjusting knob  773 , and a connecting rod  774 . The first adjusting gear  771  is mounted in the stationary housing  750  to mesh with the geared portion  721  of the central hub  720  of the driving plate  710 . The second adjusting gear  772  is coaxially mounted with the first adjusting gear  771 . The second adjusting gear  772  is disposed to mesh with the first timing gear  761  and the second timing gear  762 . 
     As is shown in  FIG. 12 , the first adjusting gear  771  has a hub  810  formed at the center thereof. The second adjusting gear  772  is formed as a geared axle in which a circular cross-sectional recess (not shown) and a non-circular cross-sectional recess (not shown) are defined. The circular cross-sectional recess is matched with the non-circular cross-sectional recess. The circular cross-sectional recess is capable of receiving the hub  810  ( FIG. 12 ) of the first adjusting gear  71 . The non-circular cross-sectional recess is capable of receiving the adjusting knob  773  which has a through hole  831  defined therein. It is to be noted that the adjusting knob  773  and part of the second adjusting gear  772  are disposed outside of the stationary housing  750  to conduct an adjustment without dis-assembling the stationary housing  750 . The connecting rod  774  can be inserted in the through hole  831  of the adjusting knob  773  and the central hub  810  of the first adjusting gear  771  to be threadedly engaged with the nut (not shown) provided in the hub  810  to have the second adjusting gear  772  frictionally engaged with the first adjusting gear  771 , so that the second adjusting gear  772  can be integrally rotated with the first adjusting gear  771 . In such an arrangement, when the sun gear  730  is driven to rotate by a motor, the first timing gear  761  and the second timing gear  762  can be rotated via the adjusting gearset  770 . 
     As can be seen in  FIG. 12 , the connecting rod  774  is preferably provided with a wing-like head  775  for facilitating manual adjustment. By means of the wing-like head  775 , the engagement or disengagement between the first adjusting gear  771  and the second adjusting gear  772  can be easily rendered. 
     As is shown in  FIG. 11 , each micro-switch  754  has an actuating lever  840  which is placed in contact with a corresponding timing gearset  760 , which includes the first timing gear  761  and the second timing gear  762 . In such an arrangement, when the motor drives the sun gear  730  in one direction to rotate the driving plate  710  to raise the roller-shutter door, the actuating lever  840  of one micro-switch  754  (first) can extend into the recess which is formed by the coincidence of the first recessed surface  811  ( FIG. 12 ) and the second recessed surface  821 , so that the first micro-switch  754  can be de-actuated to stop the motor. At this time, the roller-shutter door is moved to an upper predetermined limit position. 
     When the motor drives the sun gear  730  in an opposite direction to rotate the driving plate  710  to lower the roller-shutter door, the actuating lever  840  of the other micro-switch  754  (second) can extend into the recess which is formed by the coincidence of the first recessed surface  811  and the second recessed surface  821 , so that the second micro-switch  754  can be de-actuated to stop the motor. At this time, the roller-shutter door is moved to a lower predetermined limit position. When the aforementioned “upper predetermined limit position” or the aforementioned “lower predetermined limit position” need to be changed to be adaptable for a roller-shutter door of a different height, a corresponding connecting rod  774  can be threadedly unfastened from a corresponding nut (not shown) to allow a corresponding second adjusting gear  772  to disengage from a corresponding first adjusting gear  771 . Therefore, the corresponding second adjusting gear  772  can be turned relative to the corresponding first adjusting gear  771  to change the position of the recessed surface  811  of the first timing gear  761  relative to the recessed surface  821  of the second timing gear  762 , thereby controlling the time at which the motor can be stopped to allow a roller-shutter door to be moved to another limit position. 
     In the claims, means or step-plus-function clauses are intended to cover the structures described or suggested herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus, for example, although a nail, a screw, and a bolt may not be structural equivalents in that a nail relies on friction between a wooden part and a cylindrical surface, a screw&#39;s helical surface positively engages the wooden part, and a bolt&#39;s head and nut compress opposite sides of a wooden part, in the environment of fastening wooden parts, a nail, a screw, and a bolt may be readily understood by those skilled in the art as equivalent structures. 
     Having described at least one of the preferred embodiments of the present invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes, modifications, and adaptations may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.