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1. FIELD OF THE INVENTION 
       [0001]    This invention generally relates to automatically moving doors. More particularly, this invention relates to controlling movement of an automatically moveable door. 
       2. DESCRIPTION OF THE RELATED ART 
       [0002]    There are various automated door arrangements used in various contexts. In some instances, the automated door slides in a direction parallel to the door panel between open and closed positions. This type of arrangement is commonly used for providing access to an elevator car. 
         [0003]    Whenever an automated door moves toward a position where an edge of the door approaches another structural member in a closed position, it is possible for an object to get caught between the door and the other structural member. Various arrangements have been proposed to avoid such a situation. 
         [0004]    In the case of elevator doors, it has been known to use a safety shoe that mechanically detects an obstacle near a closed position of a door by including a bar at the leading edge of the door. If an obstacle contacts the bar, that provides an indication that the door should not be fully closed automatically to allow for the obstacle to be removed so that it will not be caught between the door and another surface. Another example approach has been to use light-based detectors that generate a sensing light beam across an opening. If an obstacle is within the opening while a door is automatically closing and interrupts the light beam, the door will not be fully closed automatically to avoid the object being caught by the door. 
         [0005]    There are limitations to such devices. For example, the safety shoe bar typically is not sensitive enough to detect relatively small objects such as a strap on a handbag or an individual finger. Additionally, such small objects may get caught if they are not located at the same position as the bar of the safety shoe. The light-based detectors are also limited in that an object may not be within the field of vision (e.g., the light beam) even though the object is in a position where it can be caught by the door. Another drawback to known light-based arrangements is that they are typically exposed to dust or debris that can interfere with proper operation. Another potential issue is presented if other light sources interfere with the detectors. 
         [0006]    Another shortcoming of such devices is that they only address the possibility of an object being caught at the leading edge of the door as it moves toward a closed position. 
         [0007]    It would be desirable to provide an improved arrangement for detecting when an object may be in a position to be caught by a door that is automatically moving. It would be beneficial to provide an arrangement that can detect the potential for an object being caught when a door is automatically moving toward a closed position, toward an open position or both. This invention addresses those needs. 
       SUMMARY OF THE INVENTION 
       [0008]    An exemplary door assembly includes a door panel that is automatically moveable between open and closed positions. At least one switch is activated responsive to an increase in a gap at an interface between the door panel and another surface that the door panel moves past while the door panel moves between the open and closed positions. A controller controls automatic movement of the door responsive to activation of the switch. 
         [0009]    In one example, the switch is supported on the door and is activated responsive to movement of the door panel away from the surface the door moves past. The switch is activated when the door panel moves in a direction generally perpendicular to a direction of movement of the door panel as it moves between the open and closed positions. 
         [0010]    One example includes two switches. One switch is activated when a first amount of pressure is applied to the door panel. This switch provides an indication that an object may be in a position where it could become caught at the interface between the door panel and the other surface. Another switch is activated responsive to more pressure on the door panel. This other switch provides an indication that an object has become caught at the interface. 
         [0011]    Another example includes a switch supported on a return panel associated with a door frame. In one example, the return panel has at least one portion that flexes or moves responsive to pressure applied by an object approaching or caught in the interface between the door and the return panel. 
         [0012]    An exemplary method of automatically controlling movement of the door panel includes determining whether a gap increases at an interface between the door panel and another surface that the door panel moves past as the door panel moves between open and closed positions. If the gap increases, an indication that an object should be moved away from the interface can be provided, automatic movement of the door panel can be at least temporarily prevented, the door panel may be automatically moved in a first direction and then in a second, opposite direction, or a combination of more than one of these may be done responsive to determining that the gap has increased. 
         [0013]    The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  schematically illustrates an example door assembly. 
           [0015]      FIG. 2  schematically illustrates one example sensor placement. 
           [0016]      FIG. 3  schematically illustrates another example sensor placement. 
           [0017]      FIG. 4  schematically illustrates another example sensor placement. 
           [0018]      FIG. 5  is a flowchart diagram summarizing one example control strategy useful in an embodiment of this invention. 
           [0019]      FIG. 6  is a flowchart diagram summarizing another example control strategy. 
           [0020]      FIG. 7  is a flowchart diagram summarizing another example control strategy. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0021]    Disclosed examples include a sensor on at least one of a door panel or a door frame that allow for detecting when a gap between the door panel and the door frame is caused by an object being in a position relative to the door panel or door frame where the object may be caught during automatic movement of the door panel relative to the frame. With the example approach, a wider variety of objects may be reliably detected and a larger number of scenarios within which an object may be caught during automatic door movement can be addressed. 
         [0022]      FIG. 1  schematically shows selected portions of an example door assembly  20 . Door panels  22  are automatically moveable between open and closed positions within an opening  24 . The example of  FIG. 1  shows the door panels  22  in a closed position. In the illustrated example, each door panel  22  moves relative to a return panel  26  as the door panels  22  move between the open and closed positions. The return panel  24  is part of the door frame in this example and is adjacent a pocket for receiving the door panel  22  in the open position. 
         [0023]      FIG. 2  schematically represents an end view of a door assembly as shown in  FIG. 1 . Such an arrangement may be useful as an elevator door on the elevator car side or the hoistway side, for example. Each of the door panels  22  in this example includes a first switch  30  that is supported on the door panel  22 . In this example, the first switch  30  comprises a microswitch that operates in a known manner to provide an electrical output upon switch activation. In this example, an arm  32  of the first switch  30  is positioned relative to a first side  34  of the door panel  22 , which faces the interface  28 . In the illustrated example, at least a portion of the first switch  30  is physically supported to remain stationary relative to a second surface  36  of the door panel  22 . 
         [0024]    Whenever pressure is applied on the first surface  34 , there will be some flexing or movement of the first surface  34  relative to the second surface  36 . In one example, this occurs because of the material used for the first surface  34 . A sheet of metal, for example, has some resiliency or flexibility such that it can be deflected toward the second surface  36  when pressure is applied onto the first surface  34  (e.g., from the bottom according to the drawing). The first switch  30  is positioned to detect such pressure on the first surface  34  and the switch arm  32  moves responsive to such pressure-induced movement of the first panel  34 . 
         [0025]    The switch  30  provides an output indicative of the detected movement of the first surface  34  responsive to an object applying pressure against the first surface  34 . The output signal from the switch  30  is provided to a controller  40  that responsively controls automatic movement of the door assembly by controlling a door mover  42 . Example control strategies are described below. 
         [0026]    In one example, the first switch  30  is configured to provide an indication of an amount of movement of the door panel  22 , such as movement of the first surface  34  relative to the return panel  26 , that corresponds to an increase in the gap at the interface  28  between the door panel  22  and the return panel  26 . An increase in the gap may correspond to deflection of the first surface  34  or movement of the entire door panel  22  in a direction that corresponds to an increase in the gap at the interface  28 . The increase will occur in some cases at only a localized portion of the interface  28 . Depending on the object, the gap along the entire interface  28  may change. 
         [0027]    Microswitches are used in one example because they have the ability to provide a significant electrical output responsive to a very minor change in position of a switch component. In other words, microswitches are used in one example because of the ability to detect very small changes in a gap between the door panel  22  and the return panel  26  at the interface  28 . 
         [0028]    The example door panels  22  also include a second switch  50 . An activating switch arm  52  in this example, moves responsive to a deflection or movement of the first surface  34  corresponding to increased pressure on the first surface  34  compared to the amount of pressure applied to cause the movement for activating the switch  30 . The switch  50  in this example provides a second level of object detection. Further movement of the first surface  34  in many circumstances will correspond to an object becoming caught at the interface  28  resulting in the increased pressure on and corresponding increased movement of the surface  34 . The second switch  50  provides an output to the controller  40  indicative of this condition. 
         [0029]      FIGS. 1 and 2  show one example door arrangement. Another example is schematically shown in  FIG. 3 . In this arrangement, the first switch  30  and the second switch  50  are supported on the return panel  26 . In this example, a portion  60  of the return panel  26  is flexible or moveable from a standard position responsive to an object approaching or getting caught in the interface  28  during automated door movement, for example. The illustrated example includes a portion  60  that is supported relative to a remainder of the return panel  26  so that the portion  60  can move between a rest position (shown in solid line) to a deflected position (shown in phantom in the drawing). 
         [0030]    A first amount of movement or deflection of the portion  60  activates the switch  30  to provide an indication that an object is approaching the interface  28 . The second switch  50  is configured to provide an indication when a further deflection occurs corresponding to an object becoming caught at the interface  28 . As can be appreciated from the illustration, when the portion  60  moves from the position shown in solid lines to the position shown in phantom lines, the corresponding gap between the return panel  26  and the door panel  22  increases. The first switch  30  and the second switch  50  are supported and configured to provide respective indications of an initial amount of an increase in the gap and a further increase. The two switches provide corresponding outputs indicating conditions that are interpreted by the controller  40  as corresponding to an object being at the interface  28  or caught I the interface  28 . 
         [0031]      FIG. 4  shows another example arrangement where first sensor  30  and a second sensor  50  are provided on door panels  22 A and  22 B. In this example, the door panel  22 A is a so-called high speed door panel and the door panel  22 B is a so-called low speed door panel. There is an interface  28  between the door panel  22 B and the return panel  26 . There is another interface  28 ′ between the door panels  22 A and  22 B. During movements between open and closed positions there is relative movement between the door panels  22 A and  22 B and between the door panel  22 B and the return panel  26 . The first switches  30  and second switches  50  allow for detecting an increase in the gap at either interface  28  or  28 ′ in the event that an object applies pressure against the corresponding door panel  22 A or  22 B. 
         [0032]      FIG. 5  includes a flow chart diagram  70  summarizing one example control approach for controlling automated movement of a door panel responsive to an indication from at least one of the switches  30 ,  50  regarding an object near or in the interface  28 . A decision is made at  72  whether the door panel of interest is stationary. If so, a decision is made at  74  whether the door is about to open. If not, the example of  FIG. 5  allows for overriding or ignoring an output from one of the switches  30  or  50  under conditions where there is no likelihood that an object is going to become caught at the interface  28  because the door is not moving or not about to move. 
         [0033]    In the event that the door is about to move, a decision is made at  76  whether the first switch  30  has been activated. If so, the example of  FIG. 5  includes issuing an audible warning at  78  and a visual warning at  80  to advise an individual that there is an object in a position relative to the door panel  22  where the object may get caught during door movement. Other examples include only a visual warning. Still other examples include using only an audible warning. In one example, after the appropriate warning has been provided, a selected amount of time is allowed to elapse before commencing door movement. 
         [0034]    In the example of  FIG. 5 , when the door panel is moving (e.g., a negative result at the decision  72 ), a decision is made whether at least the first switch  30  has been activated at  82 . If so, the door stops at  84  and a timer begins to allow a predetermined amount of time to pass. A decision at  86  is made whether that time has passed. If not, the example of  FIG. 5  includes continuing to monitor whether the switch is still activated indicating that an object is still in a position where it may be or is caught at the interface  28 . Once the appropriate amount of time has passed or the switch is no longer activated, a decision is made at  88  whether a door close instruction has issued. If so, the door is closed at  90 . If not, the door continues opening at  92 . 
         [0035]      FIG. 6  includes a flow chart diagram  100  illustrating one example approach for responding to an indication from the first switch  30  regarding the presence of an object in a position where it may become caught at the interface  28 . In other words, the flow chart diagram  100  in the example of  FIG. 6  summarizes one example approach for responding to an increase in the gap at the interface  28  that is small enough to only activate the first switch  30 . In this example, a decision is made at  102  whether the door is being opened. If not, a command is issued at  104  to ensure that the doors are fully closed. If the doors are being opened, a determination is made at  106  whether the first switch  30  has been activated. If so, the door stops moving at  108 . A timer begins running at  110  to allow for a predetermined amount of time to lapse before the door is allowed to move again. At  112 , a decision is made whether that time has passed. Until it has, the door remains stationary. After the time has passed, the door continues opening at  114 . During the time between stopping the door and opening the door, it is possible to provide at least one of an audible or visual warning to move an object away from the door panel  22  to reduce the risk of being caught at the interface  28 . 
         [0036]    In some circumstances, enough pressure is applied on the door panel  22  to increase the gap between the door panel  22  and the return panel  26 , for example, to activate the second switch  50 . As mentioned above, the second switch  50  preferably is configured to be activated responsive to an amount of movement of the door panel  22  corresponding to an object being caught in the interface  28 . The example of  FIG. 7  includes a flowchart diagram  120  summarizing one approach for responding to an output from the second switch  50 . In this example, if the door is not being opened a command to make sure the door is closed is issued at  104 . 
         [0037]    If the second switch  50  has been activated at  126 , the door stops moving at  128 . A timer begins at  130  to allow for a predetermined amount of time to pass before the door will continue moving in an opening direction. In this example, the determination regarding that amount of time is made at  132 . If that amount of time has not passed, a command is issued at  136  to move the door in a closing direction for a short period of time to assist in removing any object that was caught at the interface  28 . In this example, the determination at  132  includes determining whether the amount of time for moving the door in the closed direction has passed, also. Once that has passed, the door continues opening at  134 . 
         [0038]    In one example, continued movement of the door in the opening direction is carried out at a lower speed and with less torque than would have been done if no indication was provided from either the first switch  30  or the second switch  50 . In other words, one aspect of the example technique for controlling automatic door movement includes reducing the speed and torque used for opening a door responsive to activation of at least one of the switches to provide additional protection to the object involved. Using lower speed and lower torque also facilitates allowing for an object to be removed from the interface  28  in the event that it became caught but could not be freed during the reversed movement of the door in the closing direction for the short period of time. 
         [0039]    The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.

Summary:
An assembly ( 20 ) for controlling movement of an automatically moveable door panel ( 22 ) includes sensors ( 30, 50 ) such as microswitches positioned on at least one of a door panel ( 22 ) or a door frame member ( 26 ). The sensors provide an indication of different levels of relative movement between the door panel and the door frame member at an interface ( 28 ) between them. Such relative movement includes an increase in a gap between them that corresponds to a situation when an object is at the interface ( 28 ) and may be caught. The sensors ( 30, 50 ) respectively provide an indication of when an object may become caught and when one has. Automated movement of a door is controlled responsive to an indication of the presence of an object in a location where the object may become caught during automatic movement of the door.