SABBATH ELEVATOR

Abstract

A method of operating an elevator, the elevator having an elevator car, a motor, a controller and a counterweight (CW), the method including, for ascending of the elevator car when loaded with passengers, providing a car occupancy limiter (COL) and activating the COL by the controller for ensuring that the loaded car weighs less than the CW and controlling by the controller of the motor to not use motor rotational power; and for descending of the elevator car when loaded with passengers, where the loaded car weighs more than the CW, controlling by the controller of the motor to not use motor rotational power.

Claims

1. A method of operating an elevator, the elevator comprising an elevator car, a motor, a controller and a counterweight (CW), the method comprising: for ascending of the elevator car when loaded with passengers, providing a car occupancy limiter (COL) and activating the COL by the controller for ensuring that the loaded car weighs less than the CW.

2. The method of claim 1, further comprising: for ascending of the elevator car when loaded with passengers, controlling by the controller of the motor to not use motor rotational power.

3. The method of claim 2, further comprising: for descending of the elevator car when loaded with passengers, wherein the loaded car weighs more than the CW, controlling by the controller of the motor to limit the motor rotational speed so as to limit the motor rotational power.

4. The method of claim 3, wherein the motor energy used in either of ascending or descending is less than the energy that would be used by an empty car.

5. The method of claim 1, wherein the COL is activated by the controller after ensuring that there are no passengers inside the car.

6. The method of claim 1, wherein the elevator comprises a weight sensor, the method further comprising, when Shabbat mode is activated, by the controller, disabling the weight sensor or enabling the weight sensor only when car doors are closed.

7. The method of claim 1, wherein the elevator further comprises a mechanical weight sensor that provides an indication visible to the passengers of the combined weight of the car and passengers relative to the CW.

8. The method of claim 1, wherein the elevator further comprises an electromagnet and wherein the electromagnet is activated by the controller to engage with elevator rails so that an elevator door threshold will not subside under a floor level.

9. The method of claim 1, wherein the COL comprises a deployable barrier inside the elevator car for defining a limited occupancy area.

10. An elevator comprising: a. an elevator car; b. a counterweight (CW); and c. a car occupancy limiter (COL) for preventing the weight of the car and passengers from exceeding the weight of the CW.

11. The elevator of claim 10, further comprising a controller controlling operation of the elevator configured such that: for ascending of the elevator car when loaded with passengers, activating the COL and not using motor rotational power or limiting the motor rotational speed so as to limit the motor rotational power.

12. The elevator of claim 10, wherein the COL comprises a deployable barrier inside the elevator car for defining a limited occupancy area.

13. The elevator of claim 10, wherein the COL further comprises an occupancy sensor.

14. The elevator of claim 10, further comprising a visual door close indicator.

15. The elevator of claim 10, further comprising a mechanical weight sensor that provides an indication visible to the passengers of the elevator of the combined weight of the car and passengers relative to the CW.

16. The elevator of claim 11, further comprising a weight sensor, wherein the controller is configured, when Shabbat mode is activated, to disable the weight sensor or to enable the weight sensor only when car doors are closed.

17. The elevator of claim 11, further comprising an electromagnet configured to be activated by the controller to engage with elevator rails so that an elevator door threshold will not subside below a floor level.

18. The elevator of claim 10, further comprising a distance measurement device for determining the position of the car in a lift shaft.

19. The elevator of claim 18, wherein the distance measurement device is one of an optical distance measurement device, or a cable measuring device.

20. A method of operating a Sabbath elevator on the Sabbath, the Sabbath elevator comprising an elevator car, a motor, a controller, and a counterweight (CW), the method comprising: for ascending of the elevator car when loaded with passengers, providing and activating by the controller of a car occupancy limiter (COL) for ensuring that the loaded car weighs less than the CW and, by the controller, limiting the motor rotational speed so as to limit the motor rotational power.

21. The method of claim 20, wherein motor energy used in either of ascending or descending is less than energy that would be used by an empty car.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The disclosure is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the embodiments of the present disclosure only, and are presented in order to provide what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the disclosure. In this regard, no attempt is made to show structural details of the disclosure in more detail than is necessary for a fundamental understanding of the disclosure, the description taken with the drawings making apparent to those skilled in the art how the several forms of the disclosure may be embodied in practice. Like elements may be numbered with like numerals in different figures. In the figures:

[0051] FIGS. 1A-1J are schematic diagrams and motor energy usage graphs of a Sabbath elevator according to at least some embodiments;

[0052] FIGS. 2A-2C are schematic diagrams of a Sabbath elevator according to at least some embodiments; and

[0053] FIG. 3 is a flow diagram showing operation of a Sabbath elevator according to at least some embodiments.

DETAILED DESCRIPTION

[0054] Exemplary embodiments disclosed herein relate to a Sabbath elevator suitable for use by observant Jews. Reference is now made to FIGS. 1A-1J which are schematic diagrams and motor energy usage graphs for a Sabbath elevator according to at least some embodiments of the present disclosure. As shown in FIGS. 1A and 1B a Sabbath elevator system 100 includes: an elevator car 110 guided by elevator rails 141 suspended by a cable 114 that passes over a motor 130 and pulley 132 and is attached on a distal side to a counterweight 112. System 100 includes an elevator braking system 136 (also referred to herein as mechanical brake 136) for mechanical (friction) braking of motor 130 such as when motor 130 is stopping or stopped. Motor 130 also provides powered braking by resisting the direction of rotation of the heavier of either of the counterweight 112 or car 110 pulled by gravity.

[0055] It should be appreciated that different motor/pulley/brake arrangements are possible, and the illustrated arrangement should not be considered limiting. It should be appreciated that elevator 100 also includes other components common to elevators known in the art and only those components related to the disclosure herein are described herein. In some embodiments, cable 114 includes multiple cables each connecting elevator car 110 to counterweight 112. When elevator car 110 descends, counterweight 112 ascends and vice versa.

[0056] Elevator 100 is controlled by a controller 140 for operating elevator 100. Controller 140 includes an elevator control panel 144 and a frequency controller 142 for smooth starting and stopping of motor 130. Frequency controller 142 may also be known as an elevator inverter or frequency inverter. Controller 140 may include the functionality of control panel 144 and frequency controller 142 in a single device. Controller 140 is a computing device as described herein. Controller 140 can activate or deactivate Sabbath mode. Controller 140 includes means for interaction (not shown) with controller 140 by a human operator but it should be appreciated that the activation, monitoring, and operation of elevator components described herein is performed by controller 140 operating autonomously.

[0057] Tachometer/encoder 134 provides data about the rotation of motor 130 to controller 140. In some embodiments, tachometer 134 is a contactless tachometer. In some embodiments, tachometer 134 is an optical tachometer. In some embodiments, optical tachometer 134 uses a light source and optical sensor for detecting rotation by directing the light source at any one of one or more reflective strips, or one or more holes on the rotating component and detecting changes in the reflected light by the optical sensor to thereby convert the detected changes into a measured rotational speed. Tachometer 134 is in data communication with controller 140. Tachometer 134 may also be used to estimate the position of car 110 in a lift shaft. In some implementations, system 100 includes a floor sensor mechanism 149 for determining whether a lower door threshold 148 is level with a floor that car 110 stops at.

[0058] As shown in FIGS. 1I and 1J, in some embodiments, system 100 additionally or alternatively may include a distance measurement devices 160, 164 for determining the position of car 110 in a lift shaft. Distance measurement devices 160, 164 are in data communication with controller 140.

[0059] In some embodiments (FIG. 1I), system 100 includes an optical distance measurement device 160 for determining the position of car 110 in a lift shaft. In some embodiments, optical measurement device 160 includes a retroreflective sensor aimed at a car 110. In some embodiments, optical measurement device 160 includes a laser rangefinder aimed at a car 110. In some embodiments, a reflector 162 is positioned on car 110 for reflecting the emitted light from optical measurement device 160.

[0060] In some embodiments (FIG. 1J), system 100 includes a cable measuring device 164 that determines a position of the car 110 in a lift shaft by rolling/unrolling a measuring cable 166 attached at a distal end to car 110. In some embodiments, the length of measuring cable 166 is determined based on the measured electrical resistance of cable 166 where the electrical resistance changes as cable 166 is extended and retracted.

[0061] It should be appreciated that distance measurement devices 160, 164 may provide accurate positioning of car 110 in an elevator shaft and therefore in some embodiments, floor sensor mechanism 149 is not required when distance measurement devices 160, 164 are provided.

[0062] Counterweight 112 has a weight equal to the elevator car 110 weight plus the addition of a permitted load factor that is a percentage of the permitted load, usually in the range between 45-50% or any other ratio of the permitted load. The weight relationship of system 100 can therefore be expressed as:

A=B+Cx,

[0063] where: A=weight of counterweight 112, B=weight of elevator car 110, C=permitted load weight, and x=load factor. Thus, as above, x is typically between 40%-50%. As passengers 50 enter car 110, the combined weight of passengers 50 and car 110 approaches and then exceeds the weight of counterweight (CW) 112 until the maximum permitted load is reached. In normal (non-Shabbat mode) usage the power usage of motor 130 is described by the following Table 1 and FIG. 1C.

TABLE-US-00001 TABLE 1 Motor Power - non-Shabbat mode Motor 130 rotation Motor 130 braking Weight power power Ascending CW 112 is heavier More power needed as Less power needed as than car 110 passengers enter passengers enter Ascending Car 110 is heavier More power needed as Less power needed as than CW 112 passengers enter passengers enter Descending CW 112 is heavier Less power needed as More power needed as than car 110 passengers enter passengers enter Descending Car 110 is heavier Less power needed as More power needed as than CW 112 passengers enter passengers enter

[0064] Thus, as shown in FIG. 1C and Table 1, ascending car 110 requires progressively more energy as passengers enter and descending car 100 requires progressively less energy as passengers enter as compared to an empty car. It should be appreciated that the slope and angle of slope of the graphs of FIG. 1C (and FIGS. 1F and 1G) are illustrative and shown as smooth but may have a stepped slope as weight changes are stepped based on entry and exit of passengers 50 each having a fixed incremental weight.

[0065] It should be appreciated that braking using motor 130 requires less energy than powered rotation of motor 130. In some embodiments, braking is performed by motor 130 alone. In some embodiments mechanical brake 136 is also used in addition to braking with motor 130. In some embodiments, braking is performed using mechanical brake 136 alone.

[0066] On the Sabbath, the system 100 makes use of a combination of means to prevent increased energy usage of motor 130. It should be appreciated that while these means as described herein are used for Sabbath mode of the elevator, that the means proposed may also be used to reduce the energy usage of an elevator. These means are controlled by controller 140. The first of the means is, by controller 140, to disable powered rotation of motor 130 for moving of car 110, and relying on gravity to pull the heavier side down, and to only use motor 130 for braking where needed.

[0067] In the second of the means, system 100 includes means for limiting occupancy of the car 110 such that the combined weight of car 110 and passengers 50 is less that the weight of counterweight 112. In some embodiments, the means includes a car occupancy limiter (COL) 150 (FIGS. 1D-1E) that deploys when Sabbath mode is activated in one or both of ascending and descending as described below. An embodiment of COL 150 as shown in FIGS. 1D-1E includes a deployable barrier 152 such as but not limited to inner doors 152 inside car 110 that close off closed part 156 of the elevator to therefore reduce the amount of occupancy area 154 that passengers 50 can occupy. The weight relationship of system 100 with COL activated can therefore be expressed as:

A>B+D,

[0068] where: A=weight of counterweight 112, B=weight of elevator car 110, D=weight of passengers 50 that can fit into occupancy area 154. As passengers 50 enter car 110 with COL 150 activated, the combined weight of passengers 50 and car 110 approaches but does not exceed the weight of counterweight 112. COL 150 thus ensures that the weight of counterweight 112 is not exceeded.

[0069] As shown in FIG. 1E, inner doors 152 are positioned in the middle of elevator car 110, but this should not be considered limiting and inner doors 152 are positioned as needed to limit the occupancy area 154 inside elevator car 110. The inner doors 152 of FIGS. 1D-1E are shown as hinged doors that swing closed but optionally any other form of inner doors 152 or deployable barrier (not shown) may be provided to serve the purpose of limiting area 154. In some embodiments, inner doors 152 are any form of door, gate or barrier and the door of the embodiment of FIGS. 1D-1E should therefore not be considered limiting. COL 150 is therefore activated as part of activation of Sabbath mode by controller 140 for system 100 as described further below.

[0070] In the third of the means, frequency controller 142 is programed to keep the energy usage below the maximum used by an empty car and also at a stable energy usage level that is adjusted according to the car 110 weight. The stable energy usage is achieved by adjusting the car speed to <=the car 110 nominal speed depending on the car weight. Nominal speed is a suitable, rounded speed value for classifying the typical speed range of car 110. In a non-limiting example, an ascending car 110 that would normally travel at a nominal speed of 5 m/s may be pulled by motor 130 at a speed of 4 m/s thus enabling continued use of motor 130 while ensuring that motor 130 energy usage does not exceed an allowable level. As the weight of car 110 increases, motor 130 uses less energy (speed is reduced) so as not to exceed the energy usage limit. In some embodiments, a point is reached where motor 130 is not used as described above aside from braking where needed.

[0071] Examples are provided below for combinations of the three means proposed herein.

[0072] In a first example, as shown in FIG. 1F and table 2, with COL 150 activated for both directions and motor 130 not used for powered ascending movement, energy usage, including braking power, does not exceed the baseline usage of an empty elevator.

TABLE-US-00002 TABLE 2 Motor Power - Shabbat mode, COL activated for ascending and descending Motor 130 rotation Motor 130 braking Weight power power Ascending CW 112 is always Motor 130 not used, Less power needed as heavier than car gravity pulls CW 112 passengers enter 110 due to COL down so that car 110 150 ascends Descending CW 112 is always Less power needed as More power needed as heavier than car passengers enter and car passengers enter 110 due to COL 110 gets heavier 150

[0073] In a second example, as shown in FIG. 1G and Table 3, in some embodiments, COL 150 is only activated when car 110 is ascending and deactivated when car 110 is descending. With COL 150 activated for ascending only, and motor 130 not used for powered movement ascending, energy usage, including braking power, does not exceed the baseline usage of an empty elevator.

TABLE-US-00003 TABLE 3 Motor Power - Shabbat mode, COL activated for ascending Motor 130 rotation Motor 130 braking Weight power power Ascending CW 112 is always Motor 130 not used, Less power needed as heavier than car gravity pulls CW 112 passengers enter 110 due to COL down so that car 110 150 ascends Descending CW 112 is heavier Motor 130 used but with More power needed as than car 110 less power needed as passengers enter passengers enter and car 110 gets heavier Descending Car 110 is heavier Motor 130 not used, More power needed as than CW 112 gravity pulls car 110 passengers enter down

[0074] As shown in FIG. 1G, descending with overweight will not use more braking energy than was needed for ascending of the completely empty car due to the use of one of motor 130 braking alone, combined motor 130 and mechanical brake 136, or mechanical brake 136 alone.

[0075] In a third example, as shown in FIG. 1H and Table 4, in some embodiments, COL 150 is only activated when car 110 is ascending and deactivated when car 110 is descending. In addition, the speed of car 110 is adjusted dynamically to limit motor 130 energy usage to a stable amount less than or equal to the energy usage of an empty elevator. With COL 150 activated for ascending only, and the speed of car 110 adjusted dynamically, motor 130 energy usage, including braking power, does not exceed the baseline energy usage of an empty elevator. In some embodiments, COL is activated for both ascending and descending such that CW 112 is always heavier than (loaded) car 110.

TABLE-US-00004 TABLE 4 Motor power - Shabbat mode, COL activated for ascending, car speed reduced Motor 130 rotation Motor 130 braking Weight power power Ascending CW 112 is always Motor used with varying Less power needed as heavier than car 110 speed and stable energy passengers enter due to COL 150 usage, gravity pulls CW 112 down so that car 110 ascends Descending CW 112 is heavier Motor 130 used but with More power needed as than car 110 less power than empty passengers enter needed as passengers enter and car 110 gets heavier. Also car speed reduced if needed. Descending Car 110 is heavier Motor 130 used, gravity More power needed as than CW 112 (only pulls car 110 down and passengers enter when COL car speed is up to deactivated) nominal speed

[0076] In some embodiments, occupancy sensor 158 is provided to detect that elevator car 110 is empty before COL 150 activates and inner doors 152 close to prevent trapping of passengers 50 inside area 156. Since occupancy sensor 158 cannot be activated when passengers are in car 110 (since those passengers 50 would then be breaking the Sabbath by activating the sensor 158), passengers 50 must first be given the opportunity to exit car 110. In some embodiments, when system 100 is about to activate COL 150, indicator 122 provides a visual indication that all passengers 50 must exit car 110. Following a waiting period sufficient for passengers to exit car 110, doors 116 are closed and occupancy sensor 158 is activated. If no passengers are detected then COL 150 is activated. If passengers 50 are detected by occupancy sensor 158 then COL 150 is not activated, doors 116 are opened and indicator 122 again provides a visual indication that all passengers 50 must exit car 110. The process is repeated until all passengers exit car 110 and COL 150 can be activated.

[0077] When Sabbath mode is activated, before the elevator doors 116 close, indicator 122 provides a visual indication that elevator doors 116 are about to close to warn passengers to step inside or stay outside of elevator car 110 and to stay away from the doors. Door close indicator 122 includes a light source in communication with the door close mechanism of elevator car 110. The light source of indicator 122 may use any lighting technology including but not limited to LED, xenon and so forth. Door close indicator is here shown inside elevator car 110 but is optionally positioned outside of car 110 or optionally duplicated and positioned both inside and outside of car 110.

[0078] Weight sensor 120 (also referred to herein as load sensor 120) operates continually regardless of the entry of passengers into elevator car 110. As a non-limiting example, the weight sensor system weighs the cabin every tenth of a second and hence does not perform any additional operation caused by the entry of a passenger 50 into elevator car 110. Weight sensor 120 determines the weight added by passengers 50. The added weight information is used by controller 140 to adjust the torque of motor 130 when motor 130 moves cable 114. In some embodiments, weight sensor 120 is disabled when Shabbat mode is activated and frequency controller 142 is used to monitor weight by sensing the weight resistance.

[0079] In some embodiments, a mechanical weight sensor 121 is provided. Mechanical weight sensor 121 provides an indication on gauge 123 of the combined weight of car 110 and passengers 50. Gauge 123 is visible to passengers 50 inside car 110 and provides a clear indication that the combined weight has exceeded or is close to exceeding the weight of counterweight 112. Passengers 50 can therefore understand that one or more passengers 50 will need to exit car 100 in cases of overweight. In some embodiments, mechanical weight sensor 121 is used as an alternative to COL 150 such that elevator doors 116 will not close when mechanical weight sensor 121 and gauge 123 shows a combined weight has exceeded or is close to exceeding the weight of counterweight 112.

[0080] In some embodiments, when operating in Shabbat mode as described herein, with COL 150 activated, motor 130 is not used for pulling car 110 upwards (see tables 2 and 3). Thus, where passengers 50 cause car 110 to be heavier than counterweight 112 during ascending of car 110 (such as by squashing too many passengers 50 into occupancy area 154), the closing of doors 116 and release of brake 136 will result in car 110 descending. On floors other than the bottom floor, height sensors will trigger a stop of car 110 at the next lowest floor. For the lowest floor there is no lower floor and therefore, in some embodiments, a boundary switch 138 is provided below the lowest floor 70 that car 110 stops at. Where too many passengers enter car 110 in Shabbat mode and car 110 starts to descend below the lowest surface 70, boundary switch 138 will trigger controller 140 to activate motor 130 to pull car 110 back level with lowest surface 70. Once passengers 50 have excited car 110 and counterweight 112 is heavier, car 110 will be able to ascend.

[0081] As described above, when car 110 stops at a floor 70, floor sensor mechanism 149 determines whether a door threshold 148 is level with the floor 70. Alternatively, distance measurement devices 160, 164 may be used to determine that door threshold 148 is level with the floor 70. Due to the elasticity of the elevator cables 114, car 110 may subside below the floor 70 level after stopping as passengers enter car 100 resulting in motor 130 activating to pull car 110 back level. In some embodiments, system 100 therefore includes an electromagnet 139 for holding car 110 in position, level with a floor where car 110 stops. In some embodiments, the electromagnet 139 is fixedly attached to the car 110, such as to a car shoe (not shown), such that, when electromagnet 139 is energized it will engage with elevator rails 141 thus ensuring that car 110 (more specifically car door threshold 148) remains level with the floor 70 where car 110 stops. Thus, when operating in Shabbat mode as described herein, motor 130 will not need to be activated for pulling car 110 upwards when car 110 reaches a floor 70 as electromagnet 139 will prevent car 110 from subsiding below the floor 70 level. In some embodiments, electromagnet 139 is in data communication with controller 140.

[0082] In some embodiments, where passengers 50 cause car 110 with COL 150 activated to be heavier than counterweight 112 during ascending of car 110 (such as by squashing too many passengers 50 into occupancy area 154), motor 130 is activated by controller 140 to hold car 100 at the current floor, but not to power an ascent, until one or more passengers exit from car 110 such that counterweight 112 is heavier and can pull car 110 up using gravity.

[0083] In some embodiments, when in Shabbat mode, car 110 will stop at every floor (or alternate floors) while ascending, and not stop during descent in order to maximize use of gravity and inertia while preventing buildup of inertia for ascent. In some embodiments, in Shabbat mode, car 110 stops at every floor or alternate floors during descent.

[0084] FIGS. 2A-2C show an existing elevator that is retrofit with components to create system 200 according to some embodiments. As shown in FIG. 2A, elevator system 200 includes an elevator car 10 guided by elevator rails 141 suspended by a cable 14 that passes over a motor 30 and pulley 32 and is attached on a distal side to a counterweight 12. Elevator 200 is controlled by a control panel 40. Tachometer/encoder 34 provides data about the rotation of motor 30 to control panel 40. Brake 36 provides mechanical braking of motor 30. It should be appreciated that different motor/pulley/brake arrangements are possible, and the illustrated arrangement should not be considered limiting. It should be appreciated that elevator 200 also includes other components common to elevators known in the art and only those components related to the disclosure herein are described herein. In some embodiments, elevator 200 already supports Shabbat mode, such as stopping at every or alternate floors and sounding a buzzer when the doors are about to close, but does not operate according to a Shabbat mode acceptable to all observant Jews and therefore needs upgrading as below.

[0085] For enabling Shabbat mode in accordance with the requirements as described herein, a Shabbat mode kit including one or more of the following components are added/exchanged to system 200 as shown in FIG. 2B: Controller 140 including frequency controller 142, optical tachometer 134, load sensor 120, COL 150, mechanical load sensor 121, gauge 123, boundary switch 138, electromagnet 139, distance measurement devices 160, 164 and door close indicator 122. The operation of these components is as described for the like-numbered components in the description of FIGS. 1A-1G.

[0086] Controller 140 including frequency controller 142 is connected to control panel 40 for operating of elevator system 200. In some embodiments, control panel 40 may undergo a software upgrade and with the addition of frequency controller 142 becomes controller 140. In some embodiments, an existing frequency controller 142 is used and control panel 40 undergoes a software upgrade to become controller 140. Controller 140 is adapted to interface and integrate into multiple different control panel 40 types as manufactured for different lift vendors and types of elevators. In one embodiment, controller 140 is installed into an existing elevator installation and adds functionality as described herein with reference to FIGS. 1A-1G to existing elevator 200.

[0087] Controller module 140 preferably can control and make changes to control panel 40. As a non-limiting example, controller 140 can activate or deactivate Sabbath mode, or can perform any activities that are provided via panel 40.

[0088] Controller 140 is in data communication with the added components as shown in FIGS. 2B and 2C for operation of elevator system 200 in the same way as operation of elevator 100 as described above with reference to FIGS. 1A-1G. An embodiment of COL 150 as shown in FIG. 2C includes inner doors 152 inside the car 10 that close off closed part 256 of the elevator car 10 to therefore reduce the amount of occupancy area 254 that passengers 50 can occupy. As above, other means may be provided for limiting occupancy of car 10 including mechanical weight sensor 121 or a moveable barrier.

[0089] Reference is now made to FIG. 3 which is a flow diagram showing operation of a Sabbath elevator according to at least some embodiments of the present disclosure. In step 302 of process 300, based on the time of day and the day of the week, and having determined that Sabbath is about to start, controller 140 activates Sabbath mode for elevator 110. In step 304 COL 150 is activated following determination by controller 140 that area 156 is empty.

[0090] In step 306, car 110 ascends, stopping at every or alternate floors. After each stop, before doors 116 close, visual indicator 122 is activated. At the uppermost floor before starting descent, in step 308, COL 150 is deactivated. In step 310, car 110 descends directly to the lowest floor. Alternatively car 110 stops at every or alternate floors during descent.

[0091] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

[0092] Although the disclosure has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present disclosure.