2. Description of the Relevant Art Elevator door systems include at least one door that moves between open and closed positions. There are two basic door configurations. Center-opening doors include a pair of doors that engage each other at a generally central position relative to a car frame in a closed position. The doors move away from each other towards opposite sides of the car frame in response to an open command. Side opening doors or multispeed doors include one or two door sections that engage one side of the car frame or cabin in the closed position. The doors move away from the closed position in response to an open command.

In either configuration, the door or doors typically move along a track.

When the doors are closed, some slight gaps remain between the top, bottom, and sides of the doors and the cabin or car frame. These openings or gaps form a free path around the doors through which exterior noise can intrude or air can flow.

During elevator operation, airborne noise levels within the elevator car are increased due to air flowing through the free path around the doors, which decreases ride quality. Further, intrusion of the exterior noise through the free path is typically a louder noise than windage in the free path opening.

One solution to this problem has been to utilize a hard plastic obstruction detection bar in the door. The obstruction detection bar reduces the vertical gaps, however, such a bar does not completely eliminate the gaps. Another solution involves mounting wiper-style seals to the car frame to completely eliminate the gaps, however, this solution also has disadvantages. During each open and close operation, the door wipes against the seal, which causes wear. Due to the high volume of door openings and closings during elevator operation, these seals wear quicldy and cease to be effective.

This invention is an improved door and seal arrangement that provides a compressive sealing force and avoids the difficulties mentioned above.

SUMMARY OF THE INVENTION In general terms, this invention is an elevator door assembly that includes a door supported for movement relative to a car frame along a track. A seal is positioned between the door and the car frame. As the door moves toward a completely closed position, the door compresses the seal, which reduces airborne noise levels inside an elevator car. As the door moves from a closed position to an open position, the seal is released from compression so that the seal is no longer in contact with the door. This eliminates wiper or wearing forces on the seal due to movement of the door.

In one example, the track defines a door path as the door moves between the open and closed positions. The track includes a first track portion defining a first path segment and a second track portion defining a second path segment that is non- parallel to the first path segment. The door applies a compressive sealing force against the seal as the door moves from the first track portion to the second track portion.

In one disclosed embodiment, the first path segment is a generally linear path that runs parallel to the portion of the car frame that is aligned with the opening to the cabin, while the second path segment is a curved path that curves from the linear path toward the car frame. Thus, when the door is in the closed positioned, the door is closer to the car frame than when the door is in the open position.

In one example, the compression seal can be mounted to either the door or car frame. Compressing the seal between the door and the car frame improves ride quality by reducing undesirable noise and vibrations. The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically illustrates a top view of an elevator door assembly including a center-opening door configuration.

Figure 2 schematically illustrates a top view of an elevator door assembly including a side-opening door configuration.

Figure 3 schematically illustrates an elevator door assembly incorporating the subject invention that can be used in either of the configurations shown in Figures 1 and 2.

Figure 4 schematically illustrates an elevator door assembly incorporating the subject invention for the configuration shown in Figure 1, where the door assembly is in the open position.

Figure 5 is the door assembly of Figure 4 in a partially closed position.

Figure 6 is the door assembly of Figure 4 in the fully closed position.

Figure 7 schematically illustrates an elevator door assembly incorporating an alternate embodiment of the subject invention that can be used in either of the configurations shown in Figures 1 and 2.

Figure 8 schematically illustrates an elevator door assembly incorporating an alternate embodiment of the subject invention for the configuration shown in Figure 1, where the door assembly is in the open position.

Figure 9 is the door assembly of Figure 8 in a partially closed position.

Figure 10 is the door assembly of Figure 8 in the fully closed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As seen in Figure 1, an elevator 10 includes center-opening doors 12 that move between open and closed positions to provide access to an elevator car 14.

The doors 12 are mounted for movement relative to a car frame 16. The center- opening doors 12 are positioned at a generally central location in the car 14 and include a pair of doors 12a, 12b that move away from one another towards opposing sides of the car 14 in response to an open command.

As seen in the example of Figure 2, the elevator 10 includes a side-opening door 18 instead of a center-opening door 12. The side-opening door 18 engages one side 19 of the car frame 16 in the closed position and moves away from the car

frame 16 in response to an open command. Other door configurations are possible and within the scope of this invention.

In order to reduce airborne noise levels in the car 14, a seal 20 is installed in the elevator 10. The seal 20 can be formed from any type of compressive seal material known in the art. Also, the seal 20 can be used in either the center-opening 12 or side-opening 18 door configuration. While the seal 20 is preferably mounted near the top and bottom segments of the doors 12 or 18, the seal 20 could also be installed along other portions of the door, such as the vertical side segments of the doors. The following description of the seal 20 refers to a center-opening door 12 configuration shown in Figure 1, however, it should be understood that the seal 20 in the side-opening door 18 configuration would operate in a similar manner.

The seal 20, shown in Figure 3, is installed between the car frame 16 and the door 12. The door 12 is supported on a track 22 for movement relative to the car frame 16. The track 22 defines a door path as the door 12 moves between the open and closed positions.

The track 22 includes a first track portion 24 and a second track portion 26 that is non-parallel to the first track portion 24. The first track portion 24 defines a generally straight or linear path segment that runs parallel to a portion of the car frame 16 that is aligned with the opening to the cabin. The second track portion 26 defines a generally curved path segment that curves inwardly from the first track portion 24 toward the car frame 16. The curved path segment is positioned at the initially opening or final closing door position on the track 22.

The seal 20 can be mounted to either the door 12 or the car frame 16. As the door 12 moves from the first track portion 24 and along the second track portion 26, the seal 20 is compressed between the door 12 and the car frame 16 to eliminate any gaps or openings at the interface between the doors 12 and the car frame 16. This compressive sealing force significantly reduces airborne noise levels in the elevator car 14.

The compressive sealing force also provides a preload for the door 12 and any associated door operating components (not shown) so that undesirable vibrations are dampened during elevator operation. The preload occurs as a result of the curved path segment 26 on the tracks 22. Because the second track portion 26 is

curved, the door 12 is forced into a position closer to the car frame 16 (i. e. the door 12 is preloaded against the seal 20), when in the closed position than when in the open position This is shown in greater detail in Figures 4-6, which illustrate movement of the door 12 from an open position to a closed position.

Figure 4 shows the elevator doors 12a, 12b and associated hoistway or landing doors 30a, 30b in an open position at a landing 32. The seal 20 is not in contact with the doors 12a, 12b in this position.

In response to a close door command, the hoistway doors 30a, 30b and the elevator doors 12a, 12b begin to close, as shown in Figure 5. The doors 12a, 12b do not contact the seal 20 until the doors 12a, 12b reach the second track portion 26, which guides the doors 12a, 12b towards the seal 20. As the doors 12a, 12b move inwards on the tracks 22, the seal 20 is compressed.

When the elevator doors 12a, 12b are in the fully closed position, shown in Figure 6, the seal is compressed between the doors 12a, 12b and the car frame 16.

The hoistway doors 30a, 30b are also closed and are released or unlocked from the elevator doors 12a, 12b, as lcnown, to allow the elevator 10 to move to the next building floor or landing 32.

Because the seal 20 is only in contact with the doors 12a, 12b at the final closing position, there is no frictional wiping or wear forces that can degrade the seal 20. Further, the initial motion of the door 12 upon receipt of an open command is a movement outwards away from the car frame 16, which releases the compression on the seal 20 without the wear and tear that is normally associated with sliding motion applied across seals.

Another example of a seal assembly 40 is shown in Figure 7. In this configuration, the seal assembly 40 includes a compressive seal member 42 and a magnetic element 44. The magnetic element 44 generates a magnetic sealing force between the door 12 and the car frame 16. The seal member 42 and magnetic element 44 operate in a manner similar to that of a refrigerator door seal and can be used for less pressure and higher performance sealing. The compressive seal member 42 operates similar to that of seal 20 described above.

An alternate embodiment of the invention is shown in Figures 8-10. In this embodiment, a non-parallel track portion is not required to compress the seal 20.

Instead, a pivoting mechanism 50 moves the linearly moving door 12 towards the car 14 for compression of the seal 20 at the end of the door movement cycle through the slack and compliance in a door guidance mechanism 52.

As shown in Figure 8, the pivoting mechanism 50 includes at least one pivot arm 54 mounted to the frame 16. Preferably, a pair of arms 54 are mounted to the top and bottom of the frame 16 at each door 12 location. The pivot arms 54 include a hook 56 at a distal end. The hook 56 selectively engages pins 58 mounted to the top and bottom of each door 12.

The door guidance mechanism 52 can be any type of guidance mechanism known in the art. In this example, the guidance mechanism 52 includes rollers 60 that have a certain amount of slack or compliance to allow some door motion perpendicular to the door plane. As the door 12 begins to close, see Figure 8, the pins 58 are moved toward the hooks 56. The pivot arms 54 are preferably spring- loaded such that when disengaged, they are always in position to accept the pins 58 into the hooks 56.

As the door 12 continues to close, the pins 58 engage the hooks 56, see Figure 9, to passively pull the door 12 incrementally inwards at the end of travel.

This movement compresses the seal 20, see Figure 10. When the door 12 is opened, the pins 58 are free to move out of engagement with the hooks due to the ramped portion 62 or the pivot arms 54. One benefit with this embodiment is that it can be retrofitted into existing systems without requiring installation of new tracks.

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.