ELEVATOR DOOR ASSEMBLY

1. Field of the Invention [oooi] This invention generally relates to elevator doors. More particularly, this invention relates to controlling a direction of movement of elevator doors.

2. Description of the Related Art

[0002] Elevator systems typically include a set of doors that are considered the elevator car doors because they move with the elevator car through a hoistway. At each landing, there are a set of hoistway doors that remain at the landing. When the elevator car is appropriately aligned with the landing, a door coupler arrangement couples the elevator car doors to the hoistway doors so that they move in unison between open and closed positions to provide access to the elevator car, for example. [0003] There are a variety of door coupler arrangements that are known. One type includes a cam-type arrangement and a door reversal switch. The cam-type arrangement allows for a coupler member that is received between rollers on a hoistway door to pivot in a manner that actuates the door reversal switch if the doors contact an object while moving in a closing direction, for example. One difficulty associated with such arrangements is that the cam-type arrangement moves into a position for activating the door reversal switch as the doors are approaching a closed position even if there is nothing in the way of the doors. It is necessary, therefore, to override the signal from the door reversal switch within a significant range of the closed position. Overriding the door reversal switch in this range presents the possibility for a relatively small object to become caught between the doors.

[0004] The Japanese Kokai Patent Application Numbers 2000-118923 and 2001-58780 each disclose such an arrangement.

[0005] Figures IA, IAA, IB and IBB schematically illustrate operation of one such door arrangement. Elevator car doors 22 are associated with hoistway doors 24 when an elevator car is at a corresponding landing. A door mover 30 includes a motor 32 and a cam-type arrangement 34 that moves responsive to activation of the motor 32. In this example, a coupler member is received between rollers 36 and 38 on the hoistway doors 24. Figures IA and IAA schematically illustrate the doors moving in a closing direction.

[0006] Figures IB and IBB show an object 40 caught between the elevator car doors 22. In this example, the size of the object 40 is such that the doors 22 do not contact the object 40 until they are within the range that is the reversal overriding range. In this range a door reversal switch is effectively inoperative and it is possible for the object 40 to become caught between the doors 22.

[0007] A typical reversal overriding range is approximately double the release stroke of the door coupling arrangement. Objects of a 20 millimeter size, for example, can be caught between the doors when they are being fully closed and they do not reverse responsive to contact with the object. In the reversal overriding range of Figure IB, even though the cam-type arrangement 34 is in a position to activate a door reversal switch (not shown), the motor 32 continues to move the doors in the closing direction resulting in the object 40 being caught between the doors.

[0008] Figures 2A-2CC schematically show a door reversal operation when a coupling device as described in Japanese Kokai Patent Application Number 2000- 1 18923 is used. As shown in Figures 2A and 2AA, even when a relatively large object 40 is caught when the doors 22 are being closed, the doors cannot be reversed because the door reversal overriding range is wide. In this example, a force is applied in the full closure direction even while the object 40 is between the doors 22. The type of door motion schematically shown in Figure 2A results in movement of the cam-type arrangement 34 as schematically shown.

[0009] When the doors reverse direction in Figure 2B, the position of the cam- type arrangement 34 is such that the closure member may not be appropriately aligned between the rollers 36 and 38 on the hoistway doors 24. Accordingly, the situation schematically shown in Figures 2C and 2CC may result where the hoistway doors are not driven in unison with the elevator car doors 22 because the coupler member of the cam-type arrangement 34 is not received between the rollers 36 and 38.

[00010] There is a need for an improved door assembly that provides the ability to use a cam-type arrangement with a door reversal switch that does not suffer from the shortcomings and drawbacks described above. It would be useful to provide such a door arrangement that has a much narrower range where the door reversal switch must be overridden. Additionally, it is desirable to avoid a situation where a door coupler member is moved into a position where the door coupler member may not properly engage coupling rollers on a hoistway door to avoid a situation where elevator car doors and hoistway doors are not moving together as desired.

SUMMARY OF THE INVENTION

[00011] An exemplary door assembly comprises a first door. A door mover automatically moves the first door between open and closed positions. A door reversal switch is operative to cause the door mover to change a direction of automatic door movement. A coupler member couples the first door with a second door such that the doors move together. The coupler member moves with a portion of the door mover in a direction of door movement. The coupler member is moveable relative to the portion of the door mover for activating the door reversal switch responsive to at least one of the doors contacting an object during automatic door movement. A biasing device biases the coupler member against the movement relative to the portion of the door mover to avoid activating the door reversal switch.

[00012] In the event that the doors encounter an obstruction, the closure member moves against the bias of the biasing device for activating the door reversal switch.

[00013] 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

[00014] Figures IA, IAA, IB and IBB schematically illustrate door movement in a prior art arrangement.

[00015] Figure 2A, 2AA, 2B, 2BB, 2C and 2CC schematically illustrate door movement in another prior art arrangement. [00016] Figure 3 is a perspective illustration of selected portions of an example door assembly designed according to an embodiment of this invention.

[00017] Figure 4 schematically illustrates selected portions of the embodiment of Figure 3.

[00018] Figure 5 shows one example biasing device useful with the embodiment of Figure 3.

[00019] Figures 6A, 6AA, 6B and 6BB schematically show a door operation using an example embodiment of this invention.

[00020] Figures 7A, 7AA, 7B, 7BB, 7C and 7CC schematically show door operation using another example embodiment of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[00021] Figure 3 diagrammatically illustrates selected portions of a door assembly 50. This example embodiment is useful, for example, for moving a first door such as an elevator car door 22 and a second door such as a hoistway door 24 together. The illustrated example includes a door hanger 52 that can be connected with an elevator car door 22 in a known manner. A door mover 54 causes movement of the door hanger 52, which causes movement of the corresponding first door.

[00022] In the illustrated example, the door mover 54 includes a motor 56 that drives a belt 58 around a loop including a follower pulley 60.

[00023] A bracket 62 is connected with the belt 58 in a known manner so that the bracket 62 moves responsive to movement of the belt 58. In the illustrated example, the bracket 62 moves along a track 64 door hanger 52. As can best be appreciated from Figure 4, the bracket member 62 supports a coupler member 66 that is pivotally mounted at 68. The coupler member 66 can pivot relative to the bracket 62 during door movement. An actuator plate 70 is coupled with the coupler member 66 and can pivot about a pivot point 72 which is also supported on the bracket 62.

[00024] A door reversal switch 74 is also supported on the bracket 62. When the coupler member 66 moves about the pivot point 68 causing rotation of the actuator plate 70 about the pivot 72, the door reversal switch 74 is activated. Such movement of the coupler member 66 occurs, for example, when the doors is being moved by the door mover 54 encounter an obstruction (e.g., contact an object in the path of door movement). The door reversal switch 74 causes the motor 56 to stop and to reverse the direction of door movement. In the illustrated example, the door reversal switch 74 can be any switch that will alternately turn on and off responsive to repeated movements of an actuator such as the actuator plate 70.

[00025] The illustrated example includes a biasing device 80 that biases the coupler member 66 against movement relative to the bracket 62 into a position where the actuator plate 70 will not move to actuate the door reversal switch 74. In this example, a cord 82 has one end secured to a mounting portion 84 of the bracket 62. The biasing device 80 applies tension on the cord 82 to urge the bracket 62 and the coupler member 66 in a direction consistent with movement of the door hanger 52 during a door closing operation in one example. The cord 82 in the illustrated

example is parallel to the belt 58 such that it pulls the coupler member 66 toward the biasing device 80

[00026] The biasing device 80 in the illustrated example is associated with the motor 56 by tension realized by a spπng or the descent of a weight, for example A variety of biasing devices may be used as the biasing device 80 Given this description, those skilled in the art will realize how to arrange components to realize a biasing force urging the coupler member 66 in a direction of door movement at least during a door closing operation

[00027] Figure 5 schematically shows one example biasing device 80 In this example, a reel receives the cord 82 such that a tension is maintained on the cord 82 urging it to be retracted onto the reel of the biasing device 80 (e g., urging the end of the cord 82 in the direction of door movement). In this example, the cord 82 can be pulled out as the door mover 54 moves the bracket 52 in a direction away from the biasing device 80 A spπng 86 tends to urge the cord 82 in a direction to be wound within the biasing device 80 A pawl 90 and ratchet wheel 92 cooperate to prevent the spπng 86 from continuously applying a winding tension on the cord 82. When the pawl 90 contacts a stop surface 96, that prevents further winding of the cord 82

[00028] When the motor 56 of the door mover 54 is actuated, the pawl 90 is moved out of a position to engage any of the stop surfaces 96 on the ratchet wheel 92 such that the spπng 86 is operative to wind the cord 82 as the coupler member 66 and the bracket 62 approach the biasing device 80 duπng corresponding door movement in a closing direction, for example This winding action of the cord 82 maintains tension on the cord 82 and biases the bracket 62 and coupler member 66 in a direction consistent with the door movement at that time. [ooo29] When the coupler member 66 is biased in this manner, the actuator plate 70, which is in contact with an actuator portion of the door reversal switch 74, remains stationary and does not activate the door reversal switch 74 under normal door moving conditions As schematically shown in Figures 6A and 6AA, a door closing operation is performed while the closure member 66 is received between rollers 36 and 38 on a hoistway door 24 The bias applied by the biasing device 80 maintains the actuator plate 70 in a stationary position relative to the door reversal switch 74 while the coupler member 66 is in the position schematically shown in Figure 6A If an obstacle 40 is caught between the doors as schematically shown in Figures 6B and 6BB duπng a door closing operation, the door reversal switch 74 will

operate responsive to the tip of the coupler member 66 projecting to the side of the hoistway doors 24 (e.g., on the landing side), which causes movement of the actuator plate 70. Accordingly, the door reversal operation occurs as schematically shown in Figure 6C even when the doors are relatively close to a fully closed position. The size of the object 40 may be very small such as on the order of 10 millimeters, for example. The bias applied by the biasing device 80 allows for a much smaller range of door movement within which the door reversal switch 74 would need to be overridden.

[00030] The example arrangement allows for decreasing an overriding range where the door reversal switch 74 would have been overridden if the biasing device 80 were not included because the coupler member 66 would have moved into a position to activate the switch 74 during normal door movement approaching a fully closed position. With the biasing device 80, the door reversal switch 74 is not activated in the normal course of door movement, which allows for providing protection against even small objects from being caught between the doors while they are automatically moving.

[00031] When the doors are fully closed, the bias of the biasing device 80 is released, the belt 58 of the door mover 54 moves the actuator plate 70 and the door reversal switch 74 operates. A reversal overriding switch can be provided essentially just at the fully closed position or within a very narrow range of the fully-closed position of the door. Accordingly, the door reversal switch 74 will function other than when the doors are essentially at or very near the fully closed position.

[00032] Figures 7A-7CC show example operation of another example door assembly designed according to an embodiment of this invention. As can be appreciated in this example, when an object 40 is caught between the doors 22, the door coupler 66 moves in a manner that causes activation of the door reversal switch 74. In this example, the coupler member 66 returns to a position as schematically shown in Figure 7B where the coupler member 66 is received between the rollers 36 and 38 on the hoistway doors 24. Accordingly, the hoistway doors 24 and the elevator car doors 22 move in unison back toward an open position as schematically shown in Figure 7C. This is an improvement in two regards compared to the scenario to that is schematically represented by Figures 2A-2C

[00033] As can be appreciated from the example of Figures 7A-7C, an embodiment of this invention provides the advantages of providing a much smaller

reversal switch overriding range and ensuring that a door coupler member is appropriately received by rollers of a hoistway door even when a door reversal process must occur very near a fully closed position of the doors.

[00034] The disclosed examples make it possible for having only a narrow range near a fully closed position of doors as an overriding range of a door reversal switch so that the door reversal switch is effective until the fully-closed position of the door. Consequently, even when an object as small as about 10 millimeters is caught between the doors, the doors can be reliably reversed. Such small object protection is not possible with prior art arrangements that do not include the features of an example embodiment of this invention.

[00035] 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.