1. Field of the Invention

This invention generally relates to elevator systems. More particularly, this invention relates to an elevator cab having an external vertical perimeter fairing that reduces aerodynamic noise generated during elevator operation.

2. Description of the Relevant Art

Wind turbulence and associated noise is generated as an elevator cab moves within a hoistway. The generation of noise from wind turbulence becomes increasingly import as elevator cab speed and hoistway efficiency increases. Air circulation around the elevator cab produces the wind turbulence. Aerodynamic noise has a fourth-order dependence on elevator cab speed, the significance of which is apparent with the combination of high elevator cab speeds and a tight hoistway. Additionally, flow separation, or recirculation of the airflow, causes a substantial increase in unsteady pressure levels on the elevator cab for a given air speed, which increases vibrations. Pressure levels can be three to five times greater with separated flow versus non-separated flow. Thus, elimination of flow separation and the reduction of aerodynamic noise are important for high-speed elevator applications.

Various approaches have been used to address these problems. One approach shown in U.S. Patent No. 5,018,602, provides vertical shear panels on upper and lower walls of the elevator cab, along front and back edges. Movable air- deflector side and top panels are used in combination with the vertical sheer panels to enclose the upper and lower walls. These air-deflector side panels are not particularly effective for reducing turbulence along the sides of the elevator cab. This is due to the traditional approach of positioning the panels at a large angle relative to side walls of the elevator cab. This angle is typically greater than 30°. This configuration also causes increased flow separation along the side walls, which increases noise and vibrations.

Another approach, shown in JP 06305667, provides a shroud that is mounted to the upper and lower walls of the elevator cab. Typically, the shroud comprises a

blunt body fairing, which completely encloses the upper and lower walls. Both of these approaches shield air from the top of the elevator cab, and redirect airflow to the sides of the elevator cab to reduce wind turbulence.

There are several disadvantages with these traditional approaches. The shrouds and air-deflector panels are large, heavy, and difficult to install. The size, weight, and complexity of the shrouds and air-deflector panels increase overall cost. Further, because the upper and lower walls are completely enclosed, there is no access to elevator components that are mounted within, or supported on, the upper and lower elevator cab walls. Thus, if service needs to be performed on these elevator components, the shroud must be completely removed or moveable panels must be included with the air-deflector configuration that can be opened to provide service access, which further increases cost.

There is a need for an elevator fairing having an improved aerodynamic configuration that reduces noise by controlling airflow around the elevator cab. Disclosed embodiments of this invention utilize a vertical perimeter fairing that extends outwardly around a perimeter of at least one of an upper or lower elevator cab wall, leaving a center area of the upper and lower elevator cab walls open for access from outside of the cab, which avoids the difficulties mentioned above.

SUMMARY OF THE INVENTION

In general terms, this invention is an elevator cab that includes a vertical perimeter fairing (VPF) to reduce noise levels and improve ride quality as the elevator cab moves within a hoistway. The VPF reduces noise by smoothly directing airflow down the sides of the cab to reduce turbulence. The elevator cab includes a ceiling or upper wall, a floor or lower wall, a pair of side walls interconnecting the upper and lower walls, a back wall interconnecting the side walls along one edge, and a front wall parallel to and spaced apart from the back wall for interconnecting the side walls along an opposite edge. Elevator doors can be mounted within either or both of the front or back walls. The upper and lower walls are defined by a perimeter that extends along upper and lower edges of the front, back, and side walls. The VPF is mounted on at least one of the upper or

lower wall and extends at least partially about the perimeter, leaving a central area of the corresponding wall exposed for access from outside the cab.

An example VPF comprises a generally solid body member having a contoured profile. The VPF can optionally include an air relief passage to further facilitate airflow around the elevator cab. Also, the VPF could include integrally formed lack plate and hand rail portions.

In one example configuration, a VPF is mounted along each side edge of the upper or lower walls. An additional VPF can be mounted along a back edge of the upper or lower walls, or optionally, a vertical plate member can be mounted along the back edge. Another vertical plate member or VPF could be mounted along a • front edge as needed.

In one example, the VPF is mounted to the upper wall of the elevator cab. A first VPF member is mounted at the perimeter along one side edge and a second VPF member is mounted at the perimeter along an opposite side edge. Each of the first and second VPF members include an outboard surface and an inboard surface. The inboard surfaces of the first and second VPF members face each other, while the outboard surfaces face hoistway walls. In one example configuration, the outboard surfaces lie generally in a plane aligned with the respective side walls at an angle within the range of 0° to 20°. The disclosed VPF reduces aerodynamic noise and improves ride quality, especially during high-speed operation, by controlling airflow around the elevator cab without requiring complete enclosure of the upper and lower walls. 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 perspective view of an elevator cab that shows a perimeter area on an upper wall capable of receiving a vertical perimeter fairing (VPF).

Figure 2 is a perspective view of one example of an elevator cab with a VPF.

Figure 3 schematically illustrates a front view of the VPF of Figure 2.

Figure 4 schematically illustrates a front view of another example VPF.

Figure 5 schematically illustrates a front view of another example VPF.

Figure 6 schematically illustrates a front view of another example VPF. Figure 7 schematically illustrates a front view of another example VPF.

Figure 8 schematically illustrates a perspective view of the VPF of Figure 7 with support struts.

Figure 9 is a perspective view of one example of an elevator cab with the VPF of Figure 7. Figure 10 is a perspective view of an example of an elevator cab with the

VPF of Figure 5.

Figure 11 is a perspective view of another example of an elevator cab with the VPF of Figure 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As seen in Figure 1, an elevator cab shown generally at 10 includes a ceiling or upper wall 12, a floor or lower wall 14, a pair of side walls 16 interconnecting the upper and lower walls 12, 14, a back wall 18 interconnecting the side walls 16 along one edge, and a front wall 20 parallel to and spaced apart from the back wall 18 for interconnecting the side walls 16 along an opposite edge. Elevator doors 22 (see Figure 2) can be mounted along either or both of the front wall 20 or back wall 18 as known. The upper and lower walls 12, 14 have a perimeter area 24 that extends along edges adjacent the front, back, and side walls 20, 18, 16.

An elevator machine (not shown) moves the elevator cab 10 within an elevator hoistway 26 as known.

Referring to Figure 2, the elevator cab 10 includes a vertical perimeter fairing (VPF) 30 that reduces noise levels and improves ride quality as the elevator cab 10 moves within the hoistway 26. The VPF 30 reduces noise and turbulence by smoothly directing airflow down the sides of the elevator cab 10. The VPF 30 can be mounted on either or both of the upper and lower walls 12, 14 and can be made from sheet metal, fiberglass, or any other suitable material known in the art.

One example VPF configuration is shown in Figure 2. In this configuration the VPF 30 includes a first member 32 mounted within the perimeter area 24 along an upper edge of one side wall 16, and a second member 34 mounted within the perimeter area 24 along an upper edge of the other side wall 16. As known, by mounting the VPF 30 only along the perimeter area 24, a central area 46 on the upper wall 12 is left open for access from outside the cab 20. This facilitates service and maintenance operations.

The first and second members 32, 34 comprise a generally solid body 36 providing a contoured surface that directs airflow around the elevator cab 10. The first and second members 32, 34 each include an outboard surface 38 and an inboard surface 40. The inboard surfaces 40 face each other while the outboard surfaces 38 face hoistway walls. The outboard surfaces 38 intersect the respective side walls 16 in various configurations to control and direct airflow. This will be discussed below.

Vertical support beams 42 which are part of a known car frame, are positioned outboard of the first and second members 32, 34 to allow known guides supported by the support beams 42 to follow guide rails (not shown) mounted within the hoistway 26. At least one crosshead beam 44 passes through the first and second members 32, 34 to interconnect the vertical support beams 42. In the example shown in Figure 2, a vertical plate 48 is mounted within the perimeter area 24 along an edge of the top wall 12 adjacent an upper edge of the back wall 18. The vertical plate 48 is generally flat and abuts against the first and second members 32, 34 to form a "C" or "U" shape about the perimeter area 24. The vertical plate 48 could optionally be replaced with another VPF component. One such example is shown in Figure 11, which is discussed below. Finally, while Figure 2 only shows a VPF 30 on the upper wall 12, it should be understood that a similar configuration could be utilized on the lower wall 14.

The first and second members 32, 34 can be formed into various different shapes. The shape and height of the first and second members 32, 34 are preferably configured such that airflow along the back wall 18 and side walls 16 of the elevator cab 10 remains smooth and essentially turbulence-free with no flow separation.

One example of the first and second members 32, 34 is shown in Figure 3. Each of the first and second members 32, 34 includes a base portion 50 and a distal

tip portion 52. As discussed above, the first and second members 32, 34 are only mounted within the perimeter area 24, which leaves the central area 46 exposed for service access. Further, as discussed above, the outboard surfaces 38 can be considered to intersect the side walls 16 in various configurations. In the example shown in Figure 3, the outboard surfaces 38 are curved from the distal tip portion 52 to the base portion 50 and intersect the side walls 16 effectively at a tangent, indicated generally at 54.

In the example shown in Figure 4, the outboard surfaces 38 are generally straight from the distal tip portion 52 to the base portion 50 and intersect the side walls 16 at an angle α. The angle α is preferably within the range of 0° to 20°. In the example shown in Figure 5, the outboard surfaces 38 are substantially straight such that the outboard surfaces 38 are parallel to the side walls 16 (i.e., the outboard surfaces 38 intersect the side walls at an angle of approximately 0°).

In any of the examples shown, the first and second members 32, 34 can be used to replace handrails and kick plates that are traditionally mounted on top of the elevator cab. In the example shown in Figure 5, each of the first and second members 32, 34 includes an integrally formed handrail portion 60 and an integrally formed kick plate portion 62. The surfaces of the handrail portions 60 and the kick plate portions 62 can be contoured to many different configurations as needed. To relieve pressure on the upper wall 12 of the elevator cab 10, which may cause vibration, the first and second members 32, 34 can be configured to include an air relief passage 64 as shown in Figure 6. The air relief passage 64 extends through the body 36 of the first and second members 32, 34 from the inboard surface 40 to the outboard surface 38. Air relief also provides an additional benefit of pulling air away from the front of the elevator cab 10, which is the most accessible path for in- car noise.

In the configuration shown in Figure 6, the air relief passage 64 is formed within the first and second members 32, 34 just above the kick plate portion 62. In the example shown in Figure 7, the air relief passage 64 is formed within the first and second members 32, 34 just below the handrail portion 60.

In either air relief passage configuration, support struts 66 are used to provide support between the handrail portion 60 and the kick plate portion 62 as

shown in Figure 8. An example of an elevator cab 10 with the VPF 30 having the handrail portions 60, kick plate portions 62, and air relief passages 64 is shown in Figure 9. In the example shown in Figure 9, a VPF 30 is mounted to both the upper and lower walls 12, 14. One vertical plate 48 is mounted to the upper wall 12 along an edge adjacent an upper edge of the back wall 18, and another vertical plate 48 is mounted to the upper wall 12 along an upper edge of the front wall 20. The example Figure 9 includes a passage through the vertical plate 48 that accommodates the door mover. A similar configuration is used on the lower wall 14.

Figure 10 shows an example where the elevator cab 10 includes a VPF 30 with the handrail portion 60 and kick plate portion 62, but which does not include an air relief passage 64. This example shows vertical plates 48 along the back and front walls 18, 20 similar to that shown in Figure 9.

Figure 11 is similar to Figure 10 but shows a VPF 30 that includes a third member 70 that is used in place of the vertical plate 48 along the back wall 18. In this example, a vertical plate 48 is included along the front wall 20.

Figures 2 and 9-11 show examples of different combinations of VPFs 30 and vertical plates 48. It should be understood that any combination of the VPFs 30 shown in Figures 3-7 could be used in any of the configurations shown in Figures 2 and 9-11. The disclosed example VPFs provide a majority of the noise and flow separation benefits of a shrouded elevator cab without the negative features traditionally associated with a shroud, such as cost, complexity, weight, height, and impeded service access. The example VPFs reduce in-car elevator noise associated with airflow around and exterior of the elevator cab as the elevator cab moves within the hoistway.

The example VPFs eliminate flow separation on the sides of the elevator cab and correspondingly reduce turbulence levels and aerodynamic noise generation. Further, the VPFs reduce unsteady pressure levels to those comparable with a traditional shroud configuration. As flow separation is eliminated in regions of highest flow velocities, most of the benefit of a completely shrouded elevator cab is realized without having the negative effects of increased weight, height, and complexity.

Further, the example VPFs provide a significant portion of drag reduction that has traditionally been provided by the shroud. Aerodynamic drag can be used as a measure of the amount of excess energy introduced into the airflow (i.e., aerodynamic inefficiency). Wasted energy results in aerodynamic noise and vibration. Drag is also directly related to the strength of the wake trailing the elevator cab. Wake is a source of cab vibration and can significantly affect ride quality. Again, the use of the VPF provides the benefits of drag reduction without the negative effects of the shroud.

The example VPFs are especially beneficial to higher speed elevator applications where elevator cabs operate in a mid-speed range of four to six meters per second or a high-speed range where operational speeds exceed six meters per second. The VPF is also beneficial for elevator systems operating within aggressive hoistway efficiencies (i.e., high cab-area to hoistway-area ratios). The disclosed examples can also be used in a single or multiple car hoistway configurations. The illustrated VPFs utilize contoured fairing members along at least sides of the elevator cab as described above. The use of the VPF eliminates the need for handrails and kick plates by incorporating these features directly into the VPF. The VPF does not exceed the height of a traditional handrail and kick plate configuration. Another benefit is the top and bottom of the elevator cab remain exposed to the hoistway for maintenance. The VPF does not have to be moved or removed for inspection or maintenance access. Additionally, access to the sides of the elevator cab is not hindered in any way.

In certain configurations, the VPF can be integrated with a front vertical shear plate. A back vertical shear plate can also be used to facilitate airflow in close counter-weight configurations.

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.