Abstract:
A barrier mount system is disclosed which opens and closes a barrier such as a gate or garage door in response to user generated commands. Obstruction detection apparatus is provided for safety of operator. When an obstruction is sensed, the barrier movement system is inhibited from responding to user generated commands until a predetermined event occurs. The event may be passage of a predetermined amount of time or barrier movement of a particular amount.

Description:
The present invention relates to safety systems for use with automated movable barriers. 
     Many types of automatic movable barrier systems are in use today. Examples of such are garage door, gate and awning controllers. With such systems a motor is coupled to the barrier and is controlled by a controller to open and close the barrier in response to directions which are usually provided by a human operator. Some barrier movement systems incorporate sensing operations and control circuitry to provide safety of operation. For example, a garage door opener may include a force sensor to identify when the door is being pushed or pulled too hard by the motor at a given point in its travel. When too much force is sensed, an obstruction to door travel is assumed and the motor may be stopped and/or reversed to stop possibly harmful force. The use of optical or ultrasonic sensors to scan the opening being closed and opened by the barriers and to stop and/or sense door movement when a physical obstruction is detected in the opening is also known. Such safety systems rely on sensing, signaling and decision making apparatus such as a microprocessor controller to complete their safety function. A barrier movement control systems primarily respond to user initiated signals to control barrier movement. Such user signals may be transmitted from wall mounted switches or wireless code transmitters. Generally, the system is constructed so that the user initiated signals override at least some of the control signals generated by an electronic controller for system safety. Thus, in some instances human operators have been given precedence over an electronic safety system. Although existing systems have proven to be reliable and to provide a safe operating environment designs may have, in some cases, permitted panicked human interaction to override the automatic safety features. 
     SUMMARY OF THE INVENTION 
     As described below a barrier movement system comprises a controller for controlling a motor to move a barrier between open and closed positions. The controller response to user initiated commands to control the position and movement of the barrier. When an obstruction is sensed by associated apparatus the barrier movement is stopped and the controller ceases to respond to user initiated commands. 
     The cessation of response to user initiated commands may last only until a predetermined event occurs. The predetermined event may be a number of things, including the passage of a predetermined time, the movement of the barrier by a predetermined amount or the change of state of the barrier movement system. Such change of state may, for example, be when the door reaches an upper or lower travel limit or when a subsequent obstruction is sensed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a representation of an arrangement for opening and closing a garage door; 
         FIG. 2  is a block diagram representing the control structure of a barrier movement system; 
         FIG. 3  is a flow diagram showing the control of the system of  FIG. 2 ; and 
         FIG. 4  is a flow diagram of operations occasioned when an obstruction is sensed while a barrier is being moved. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings and especially to  FIG. 1  a movable barrier operator or garage door opener is generally shown therein and referred to by numeral  10 . The operator includes a head unit  12  mounted within a garage  14 . More specifically, the head unit  12  mounted to the ceiling of the garage  14  and includes a rail  18  extending therefrom with a releasable trolley  20  attached having an arm  22  extending to a multiple paneled garage door  24  positioned for movement along a pair of door rails  26  and  28 . The system includes a hand-held transmitter unit  30  adapted to send rf coded command signals to an antenna  32  positioned on the head unit  12  and coupled to a rf receiver of the head end. A switch module  39  is mounted on a wall of the garage. The wall control module  39  is wire connected to the head unit by a pair of wires  39   a . In other embodiments the wall control may communicate with the head end via rf. The wall control module  39  includes a command switch  39   b , which may be pressed by a user to operate door control commands. An optical emitter  42  is connected via a power and signal line  44  to the head unit. An optical detector  46  is connected via a wire  48  to the head unit  12 . The optical emitter  42  and detector watch, the door opening to identify possible obstructions to door travel. 
     As shown in  FIG. 2 , the garage door operator  10 , which includes the head unit  12  has a controller  70  which having the antenna  32 . The controller  70  includes a power supply  72  which receives alternating current from an alternating current source, such as 110 volt AC, and converts the alternating current to required levels of DC voltage. The controller  70  includes rf receiver  80  coupled via a line  82  to supply demodulated digital signals to a micro-controller  84 . The receiver  80  is energized by the power supply  72 . The micro-controller is also coupled by a bus  86  to a non-volatile memory  88 , which non-volatile memory stores user codes, and other digital data related to the operation of the control unit. An optical detector  90 , which comprises the emitter  42  and infrared detector  46  is coupled via an obstacle detector bus  92  to the micro-controller  84 . The obstacle detector bus  92  includes lines  44  and  48 . In other embodiments the optical detector  90  may utilize other sensing capabilities such as high frequency sound. The embodiment may also include an optional door edge detector  34  to detect physical contact of the door with an obstruction in the door&#39;s path (the opening). The wall switch  39  is connected via the connecting wires  39   a  to the micro-controller  84 . The micro-controller  84 , in response to switch closures and received rf codes, will send signals over a relay logic line  102  to a relay logic module  104  connected to an electric motor  106  having a power takeoff shaft  108  coupled to the trolley  20  to raise (open) and lower (close) the door  24 . A tachometer  110  is coupled to the shaft  108  and provides motor rotation signals on a tachometer line  112  to the micro-controller  84 ; the tachometer signal being indicative of the speed of rotation of the motor. The apparatus also includes up limit switches and down limit switches which respectively sense when the door  24  is fully open or fully closed. The limit switches are shown in  FIG. 2  as a functional box  93  connected to micro-controller  84  by leads  95 . Door open and closed limits may also be detected internally by micro-controller  84  by counters which reflect door movement from the motor rotation signals on conductor  112 . Additionally, the arrangement of  FIG. 2  may include a motor power or current sensor  122  connected to micro-controller  84 . Motor sensor senses the power and/or current used by motor  106  and generates an obstruction signal when a threshold is exceeded. 
       FIG. 3  is a flow diagram of an embodiment of operation of the system of  FIGS. 1 and 2 . The flow diagram shown in  FIG. 3  is a continuous loop which is initially entered when at system start up. The description of  FIG. 3  begins at block  101  where a check of tachometer  110  is made to determine whether door  24  is moving. In other embodiments a check of a present state of the system can be used to evaluate that the door is in motion. When the door is not in motion, flow proceeds to a block  103  where a check is made to see whether a flag has been set to indicate whether user commands are being inhibited. The setting and clearing of the inhibit flag are discussed later herein. When the user command inhibit flag is not set a check is made in block  105  to determine whether a user input has occurred. When no user input has been received, flow proceeds to block  107  to determine whether an event has occurred to result in clearing the inhibit flag. The event mentioned may be for example, the passage of a predetermined amount of time since the inhibit flag was set or the movement of the barrier by a predetermined amount since the setting of the inhibit flag. The flow will remain in the above described sub-loop consisting of blocks  101 ,  103 ,  105  and  107  until a user command input is received and detected in block  105 . 
     When a user input is detected in block  105  flow proceeds to block  109  where the user input command is responded to by beginning pre-established movement of the door. Such movement (or stoppage) is in accordance with known principles and may result in the door being moved up, moved down or stopped. For the present description it is assumed that the door has been commanded to move. After the user input is acted on in step  109  flow proceeds to step  107  to detect whether the obstruction inhibit flag is to be cleared, then onto step  101  which detects that the door is in motion and flow proceeds to block  111  to detect whether an obstruction is being sensed by the door edge detector  34 , the optical detector  90 , the tachometer  110  or the motor sensor  122 . When no obstruction is sensed flow proceeds to block  113  to determine whether an end of travel has been detected. Such an end of travel will be signaled by the open and closed limits  93  or the tachometer  110  in conjunction with a position monitoring register of the micro-controller  84 . 
     When an end of travel is detected in block  113  flow proceeds to block  115  to stop motion of the barrier. After block  115  stops the door flow proceeds to block  107  which functions as above described. 
     When block  113  does not detect the end of travel flow will continue to loop until end of travel is reached or and obstruction is detected in block  111 . When such an obstruction is sensed, flow proceeds via block  117  where the user input inhibit flag is set to block  119  where a safety response is initiated. Such a safety response is generally known and depends upon the direction of door travel and in alternate situations which sensor detected the obstruction. When the user inhibit flag is set, flow proceeds as before, however step  103  will cause the flow to ignore user command input by diverting flow from block  103  to block to block  107  without entering the user input received block  105 . Thus, further obstructions will be sensed and automatically responded to; to the exclusion of user input commands. 
     The user command inputs are excluded until the occurrence of a predetermined event. That event, which may be the passage of a predetermined amount of time or the movement of the barrier for a predetermined distance, will be detected in decision block  107  which is traversed during each loop or sub-loop through the flow diagram. When block  107  detects the occurrence of the event, a block  121  is performed where the inhibit flag is cleared. With the clearance of the inhibit flag block  103  will again cause flow to proceed through block  105  to identify whether user commands are received and to act on them as needed. 
       FIG. 4  is a flow diagram of another embodiment which permits a user to override certain types of detected obstructions. In the present description an overridable obstruction is considered to be an infra-red detector  90  detected obstruction while a non-overridable obstruction is a motor sensor  122 , a door edge  34 , a tachometer  110  detected obstruction. Other combinations of obstruction detection may be combined into overridable and non-overridable obstructions in other embodiments. 
     The general flow of  FIG. 4  is substantially the same as  FIG. 3  except that blocks  125 – 133  control the detection and implementation of the override functions. Also blocks  135  and  137  are used to test and reset an override enable flag. When door movement block  123  detects door movement, a block  125  is entered to detect whether the override flag has been set. The override flag being set represents a special condition discussed below. When the override flag is not set, flow proceeds to block  129  which detects whether an overridable obstruction has been sensed. The overridable obstruction, in the present example, is an obstruction signaled by the IR detector  90 . When no such overridable obstruction is detected flow proceeds to block  133  where a test is performed to see whether a non-overridable obstruction has been detected. When no non-overridable obstruction is sensed flow proceeds to block  113  as with the embodiment of  FIG. 3 . 
     When block  129  detects an overridable obstruction, flow proceeds to block  131  where an override flag is set and then onto block  117  in which the enable flag is set as discussed in regard to  FIG. 3 . When block  125  is next performed the override flag will be sensed and flow will proceed to block  127  where a check is performed to determine whether a user is generating a special override input. Such a special override input might comprise the continuous pressing of a wall controller button  39  or pressing a special button dedicated to this purpose. When block  127  does not detect an override input from the user flow proceeds to block  129 . Alternatively, when block  127  detects a user override input flow proceeds to block  133 , to detect a non-overridable obstruction as before. In addition to new blocks  125 – 133   FIG. 4  includes block  135  and  137  which cooperate to clear the override flag on the occurrence of an override condition. In the present embodiment the inhibit flag will be cleared by block  121  approximately 2½ seconds after it is set. The override flag will not be reset by the block  137  until approximately 90 seconds pass. Accordingly, the override input by the user will not be made active by the user input process  109  for approximately 2½ seconds after the detection of an overridable obstruction. Thereafter the inhibit flag will be cleared and the user permitted control of the system to the exclusion of the overridable obstruction detector for the remaining 0.87½ seconds before which the override flag will be reset. In this way the user, by using a special override input command, can have direct control of the system to the exclusion of overridable obstructions. 
     While there has been illustrated and described particular embodiments, 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.