A system for decoupling a barrier from a barrier movement apparatus for the manual operation of the barrier. Advantageously, the decoupling is performed in response to a wireless signal and may be done only when the barrier is determined to be in a safe position.

The present invention relates to barrier movement systems and particularly to security methods and arrangements for such systems. 
     Barrier movement systems generally include an electric motor which is coupled to the barrier and selectively powered by a controller to move a barrier between open and closed positions. When the barrier is coupled to the motor the coupling and the motor may be an impediment to the manual movement of the barrier. Should an intruder attempt to force a barrier open, such impediment is beneficial as it will usually stop the intrusion. However, when a permitted user desires to manually move the barrier the impediment may be a hardship. For example, when the source of electrical power which drives the motor is lost e.g., a power outage, then a permitted user may not be able to “back drive” the barrier movement system to gain entry to the secure area beyond the barrier. 
     Modern barrier movement systems include a mechanical apparatus for uncoupling parts of the barrier movement system from the barrier to be moved. These uncoupling systems frequently include a mechanical connection to some point along the connection between the motor and the barrier which mechanically decouples the connection. A common such decoupling arrangement includes a flexible member such as a rope or cable which is connected to a portion of the drive mechanism. When the flexible member is pulled a mechanical release is enabled which separates the connection between the motor and the barrier. Access to the decoupling apparatus must be limited or an intruder could easily enter a secure area by pulling the flexible member. Accordingly, the flexible member is available only to persons already inside the secure area or only to persons who can unlock a more publically available end of the flexible member. A need exists for an improved arrangement to allow a permitted person outside a secure area to disconnect the physical connection between a barrier and its driving apparatus to allow manual movement of the barrier. 
     SUMMARY 
     The present invention relates to remote barrier release arrangement responsive to a transmitted signal, such as an rf, sound, or optical signal, for decoupling the motor and the barrier for movement by a user. Advantageously, the remote release arrangement may include a power supply separate from that which powers the motor to power the operation of the remote release in case a primary power supply is interrupted. 
     In an embodiment the arrangement includes an electrical clutch which connects the motor to the barrier. Advantageously, the clutch is connected on the barrier side of any gear reduction to minimize the back forces required for a user to move the barrier. Such a clutch arrangement may be used on either a jack shaft type barrier movement system or a trolley-rail type. 
     Another embodiment includes a trolley-rail release system in which a trolley, driven by a motor to move a barrier may be decoupled from the motor in response to a transmitted signal. Advantageously, the decoupling of the trolley is accomplished using parts of a manual release system. The trolley decoupling system includes an auxiliary power supply to enable operation when mains power is lost. 
     A programmable controller is employed to enable the remote release arrangement disclosed herein. Advantageously, the arrangement also includes software or apparatus for determining the position of the barrier. The controller consults the barrier position before allowing release of the barrier so that the barrier may be released only when in a safe position for such release. For example, the controller may permit remote release of the barrier only when the barrier is within 6 inches of the closed position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The following description may be more readily understood when read in conjunction with the drawing in which: 
         FIG. 1  is a perspective view of an assembled rail-trolley type barrier movement arrangement; 
         FIG. 2  is a block diagram of portions of the controller and related apparatus; 
         FIG. 3  is a mechanical block diagram of a trolley including a remote release mechanism; 
         FIG. 4  is a block diagram of a controller of the release mechanism of  FIG. 3 ; 
         FIG. 5  is a plan view of a barrier movement trolley in the connected state; 
         FIG. 6  is a plan view of the barrier movement trolley in the released state; 
         FIG. 7  is a block diagram of an alternative embodiment for an electric clutch release arrangement; and 
         FIG. 8  shows an alternative embodiment for enabling a trolley release. 
     
    
    
     DESCRIPTION 
     The embodiments described herein concern the vertical movement of a garage door. It can readily be seen that the arrangements described and claimed herein also apply to other types of barriers and other types of motion. For example, the present invention is equally applicable to automated swinging barriers or horizontally sliding barriers and other types of automated barrier movement systems. 
       FIG. 1  shows an automated arrangement  10  for vertically moving a paneled door  24  along a set of guide rails  30  between a closed position as shown and an open position in which door  24  is held is a substantially horizontal position by an upper portion of rails  30 . The arrangement  10  includes a head end housing  12  which includes the items in  FIG. 2 , a motor  50 , an rf receiver  52  with antenna  54  and a controller  56 . A source of mains voltage  58  is connected to controller  56  which selectively distributes power to the individual units of  FIG. 2  as needed. The mains voltage may be the standard 110V 60 HZ household power available in the U.S. from the power grid. The controller  56  responds to rf signals from user operated transmitter  31  ( FIG. 1 ) via receiver  52 , by selectively coupling mains power from source  58  to the motor  50 . An output shaft  60  of the motor  50  is then rotated clockwise or counter-clockwise depending on the output of controller  56 . By means well known in the art a chain couples the shaft  60  to a trolley  20  which moves linearly along a rail  18  under the motor's power. The trolley is in turn coupled by a lever on  22  to a top portion of the door  24 . Trolley  20  consists of an outer portion  21  and an inner portion  23 . As is known in the art the door  24  can be released from the motor  50  by pulling downward on a rope  25  which controls a mechanical latch between inner portion  23  and outer portion  21  of trolley  20 . 
       FIG. 3  represents the trolley  20  in greater detail. Trolley  20  consists of inner portion  23  and outer portion  21  which can be unlatched by moving a lever arm  29  downwardly. When rope  25  is pulled downwardly outer portion  21  is released to slide horizontally along rail  18  without having to drive the motor  50  or its connection to trolley  20  in any way. Trolley  20  of the present embodiment also includes a release unit  27  which is shown in block diagram form in FIG.  4 . Release unit  27  includes a back-up power source  73  such as a battery, and rf receiver  71 , a controller  75 , a motor  77  and a coupling  79  between motor  77  and release lever  29 . Rf receiver  71  detects received transmissions and sends detected signals to controller  75  which decodes the detected signals to identify a request for release of the door. In the present embodiment controller  75  has been taught to recognize a signal initiated by one of the transmit buttons of a remote transmitter such as transmitter  31 . Controller  75  also checks the condition of a switch  35  for safety purposes. Switch  35  may be, for example, a tilt switch attached to connector  22  ( FIG. 1 ) which presents a closed circuit when the angle of connector  22  indicates that the door  24  is within 6 inches of being closed. When controller  75  senses a recognized received rf signal and that the door is in a safe position within 6 inches of being closed, power from backup power  23  is connected to motor  77  which responds thereto by urging release lever downwardly to unlatch the inner portion  23  and outer portion  21  of trolley  20 . The above-described embodiment allow a user to approach the door from outside the secure area and by pressing a particular transmit button on his or her remote transmitter, releasing the door for manual operation. Such is found to be most beneficial when the automatic opening provided by head end  12  is unavailable due to an interruption of mains power. 
     In the preceding embodiment the door position sensing switch  35  is described as connected to the lever arm  22 . In other embodiments the switch  35  might be attached to the door, or to the non-moving structure of the door supports or garage. The function of switch  35 , to indicate a safe door position for release operation, may be performed by many types of door sensing or switch placement. The position sensing could also be reported from the controller  56  which knows the position of the trolley as a part of its movement control function. Also the preceding embodiments show a motor  77  to disengage the trolley. Other electrically powered for such disengagement are also contemplated. For example, an electrical solenoid could be connected to the back up power source  73  to achieve such disengagement. 
       FIGS. 5 and 6  depict the mechanical structure of a preferred embodiment of trolley  20  in the idle (connected) and active (released) modes, respectively. Trolley motor  77  is connected via substantial gear reduction (not shown) to rotate a cam  41  which is attached to release lever  29 . Cam  41  engages a roller  43  of the trolley  20 . When the trolley motor  77  is powered by controller  75  it rotates cam  41  in the counter clockwise direction in  FIGS. 5 and 6 . Due to the shape of cam  41  this forces lever  29  downward in a manner similar to the movement of lever  29  in response to a manual pull on rope  25 . When cam  41  has rotated from the position of  FIG. 5  to that of  FIG. 6  the inner portion  23  and outer portion  21  of trolley  20  are released and the door can be moved without back driving the motor. At the completion of release, the cam  41  can be manually rotated into the at-rest position of  FIG. 5 , a spring (not shown) may be attached to cause the return rotation to the original state or the polarity of back up power to motor  77  reversed to rotate cam  41  in the clockwise direction. 
     Also in the preceding embodiment the release of the door for manual operation was performed on the linearly moving trolley  20 . The release of the door may also be obtained by an electric clutch in the output of motor drive  50 .  FIG. 7  represents such a clutch actuating arrangement which is a part of the head end  12 . 
     In  FIG. 7 , components having the same element number as in  FIG. 2  are substantially the same as in  FIG. 2  except as described herein. An electric clutch  85  is connected between the output shaft  60  of motor  50  and an output shaft  80  of the electric clutch drives the previously described sprocket and chain. The controller  56  is also connected to a backup power source  81  which may, for example, be a rechargeable battery. Also shown connected to controller  56  is a door sensor  83  to sense the position of door  24 . Because controller  56  is at all times in control of door movement it may keep a constant second of door position, in which case the door sensor  83  may be unneeded. Receiver  82  receives wireless transmissions and conveys detected signals to controller  56 . When detected signals are received which represent a wireless disconnect signal controller  56  checks the position of the door  24 . When the position is determined to be safe, power is applied to electric clutch  85  to release output shaft  80  from motor shaft  60 . In this way the door is manually movable without back driving motor  50  and any associated gearing. 
     In cases where mains power has been interrupted the embodiment of  FIG. 7  powers the circuitry shown (except motor  50 ) from back up power  81 . In this way the door can be released from the drive system when mains power interruption has occurred. 
       FIG. 8  shows an additional embodiment in which door release decisions are made by the controller in the head end  12  and implemented at the trolley  20 . Upon making a decision to release the door controller  56  ( FIG. 7 ) sends a signal to a transmitter  61  for transmission to a receiver  63  of the trolley  20 . Although the transmitted signal is preferred to be sent by wireless means such as rf, sound, or optics such could also be conveyed by a wire path. Receiver  63  forwards the received signal to controller  75  of the trolley  20  which responds thereto by connecting back up power  73  to motor  77 . As previously discussed, rotation of the shaft of motor  77  will release the inner and outer portions of trolley  20 . 
     While there has been illustrated and described a particular embodiment of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.