ELEVATOR SYSTEMS

Abstract

An elevator system is provided which includes a plurality of hoistway doors, a corresponding plurality of sets of non-contact switches, each set arranged to detect when a respective hoistway door is open, and a monitoring device. Each set of non-contact switches comprises a first non-contact switch arranged to open when the respective hoistway door is open and a second non-contact switch arranged to open when the respective hoistway door is open. The first non-contact switches of the plurality of sets are connected in series to form a first electrical path and the second non-contact switches of the plurality of sets are connected in series to form a second electrical path. The monitoring device is arranged to measure an electrical property of the first electrical path and an electrical property of the second electrical path to detect when a hoistway door is open.

Claims

1. An elevator system (2) comprising: a plurality of hoistway doors (10a, 10b, 10c); a corresponding plurality of sets of non-contact switches (12a, 12b, 12c), each set arranged to detect when a respective hoistway door (10a, 10b, 10c) is open; and a monitoring device (26); wherein: each set of non-contact switches (12a, 12b, 12c) comprises a first non-contact switch (14a, 14b, 14c) arranged to open when the respective hoistway door (10a, 10b, 10c) is open and a second non-contact switch (16a, 16b, 16c) arranged to open when the respective hoistway door (10a, 10b, 10c) is open; the first non-contact switches (14a, 14b, 14c) of the plurality of sets (12a, 12b, 12c) are connected in series to form a first electrical path (22) and the second non-contact switches (16a, 16b, 16c) of the plurality of sets (12a, 12b, 12c) are connected in series to form a second electrical path (24); and the monitoring device (26) is arranged to measure an electrical property of the first electrical path (22) and an electrical property of the second electrical path (24) to detect when a hoistway door (10a, 10b, 10c) is open.

2. The elevator system (2) as claimed in claim 1, wherein the monitoring device (26) is arranged to measure a resistance of the first and/or second electrical path (22, 24).

3. The elevator system (2) as claimed in claim 1, wherein each set of non-contact switches further comprises a first bypass impedance (18a, 18b, 18c) connected in parallel with the first non-contact switch (14a, 14b, 14c) and/or a second bypass impedance (20a, 20b, 20c) connected in parallel with the second non-contact switch (16a, 16b, 16c).

4. The elevator system (2) as claimed in claim 3, wherein the first and/or second bypass impedances (18a, 18b, 18c, 20a, 20b, 20c) are different.

5. The elevator system (2) as claimed in claim 4, wherein each first bypass impedance (18a, 18b, 18c) and/or each second bypass impedance (20a, 20b, 20c) is different, such that each unique combination of open and closed hoistway doors (10a, 10b, 10c) corresponds to a unique impedance of the first and/or second electrical paths (22, 24),

6. The elevator system (2) as claimed in claim 3, wherein the at least one first and/or second bypass impedance (18a, 18b, 18c, 20a, 20b, 20c) comprises a plurality of electronic components.

7. The elevator system (2) as claimed in claim 1, wherein the monitoring device (26) is arranged to measure a first electrical property of the first and/or second electrical path (22, 24) when operated in a first mode, and to measure a second electrical property of the first and/or second electrical path (22, 24) when operated in a second mode.

8. The elevator system (2) as claimed in claim 7, wherein the monitoring device (26) is arranged to switch from operating in the first mode to operating in the second mode upon detection of an open hoistway door.

9. An elevator system (102) comprising: a plurality of hoistway doors (10a, 10b, 10c) and a corresponding plurality of sets of non-contact switches (112a, 112b, 112c), each set arranged to detect when a respective hoistway door (10a, 10b, 10c) is open; and a monitoring device (126); wherein each set of non-contact switches (112a, 112b, 112c) comprises: a first non-contact switch (114a, 114b, 114c) arranged to open when the respective hoistway door (10a, 10b, 10c) is open; a first impedance (118a, 118b, 118c) connected in series with the first non-contact switch (114a, 114b, 114c); a second non-contact switch (116a, 116b, 116c) arranged to open when the respective hoistway door (10a, 10b, 10c) is open; and a second impedance (120a, 120b, 120c) connected in series with the second non-contact switch (116a, 116b, 116c); wherein the first non-contact switch (114a, 114b, 114c) and the first impedance (118a, 118b, 118c) are connected in parallel with the second non-contact switch (116a, 116b, 116c) and the second impedance (120a, 120b, 120c); wherein the sets of non-contact switches (112a, 112b, 112c) are connected in series to form an electrical path (122); and wherein the monitoring device (126) is arranged to measure an electrical property of the electrical path (122) to detect when a hoistway door (10a, 10b, 10c) is open.

10. The elevator system (102) as claimed in claim 9, wherein the monitoring device (126) is arranged to measure a resistance of the electrical paths (122).

11. The elevator system (102) as claimed in claim 9, wherein two or more first and/or second impedances (118a, 118b, 118c, 120a, 120b, 120c) are different.

12. The elevator system (102) as claimed in claim 11, wherein each first impedance (118a, 118b, 118c) is different and/or each second impedance (120a, 120b, 120c) is different, such that each unique combination of open and closed hoistway doors corresponds to a unique impedance of the electrical path (122).

13. The elevator system (102) as claimed in claim 9, wherein each set of non-contact switches (112a, 112b, 112c) comprises a bypass impedance (117a, 117b, 117c) connected in parallel with the first and second non-contact switches (114a, 114b, 114c, 116a, 116b, 116c).

14. The elevator system (102) as claimed in claim 13, wherein at least one bypass impedance (117a, 117b, 117c) comprises a plurality of electronic components.

15. An elevator system (202) comprising: a plurality of hoistway doors (10a, 10b, 10c) and a corresponding plurality of sets of non-contact switches (212a, 212b, 212c), each set arranged to detect when a respective hoistway door (10a, 10b, 10c) is open; and a monitoring device (226); wherein: each set of non-contact switches (212a, 212b, 212c) comprises at least one non-contact switch (214a, 214b, 214c), and at least one further electronic component (218a, 218b, 218c, 220a, 220b, 220c) connected in parallel with the non-contact switch (214a, 214b, 214c) so that each set of non-contact switches (212a, 212b, 212c) comprises a unique AC electrical property; the sets of non-contact switches (212a, 212b, 212c) are connected in series to form an electrical path (222); and the monitoring device (226) is arranged to measure an AC electrical property of the electrical path (222) to detect and identify an open hoistway door (10a, 10b, 10c).

Description

DRAWING DESCRIPTION

[0044] One or more non-limiting examples will now be described, by way of example only, and with reference to the accompanying figures in which:

[0045] FIGS. 1-3 are schematic views of an elevator system according to an example of the present disclosure;

[0046] FIG. 4-5 is a schematic view of an elevator system according to another example of the present disclosure;

[0047] FIG. 6 is a schematic view of an elevator system according to another example of the present disclosure; and

[0048] FIGS. 7 and 8 show alternative arrangements for impedances for use in the various examples.

DETAILED DESCRIPTION

[0049] FIG. 1 shows an elevator system 2 comprising an elevator car 4 that is driven to move in a hoistway 6 between a plurality of landings 8. Hoistway doors 10a, 10b, 10c on each landing 8 open to provide access to the elevator car 4 but otherwise remain closed to prevent unsafe access to the hoistway 6.

[0050] To ensure safe operation of the elevator system 2, the state (i.e. open or closed) of each hoistway door 10a, 10b, 10c is monitored, to prevent potentially unsafe operation of the elevator car 4 whilst any of the hoistway doors 10a, 10b, 10c is open. The elevator system 2 therefore comprises a plurality of sets of non-contact switches 12a, 12b, 12c, each set arranged to monitor the state of a respective hoistway door 10a, 10b, 10c. Each set of non-contact switches 12a, 12b, 12c comprises a first non-contact switch 14a, 14b, 14c and a second non-contact switch 16a, 16b, 16c (e.g. reed switches). Each set 12a, 12b, 12c also comprises a first bypass resistor 18a, 18b, 18c connected in parallel with the first switch 14a, 14b, 14c, and a second bypass resistor 20a, 20b, 20c connected in parallel with the second non-contact switch 16a, 16b, 16c.

[0051] In the example shown in FIG. 1, all of the first non-contact switches 14a, 14b, 14c are connected in series to form a first electrical path 22, and all of the second non-contact switches 16a, 16b, 16c are connected in series to form a second electrical path 24. The first and second electrical paths 22, 24 are connected to a monitoring device 26. The monitoring device 26 is arranged to measure an electrical property of each of the first and second electrical paths 22, 24. In this example, the monitoring device 26 is arranged to measure the resistance. This allows the monitoring device 26 to detect when any one of the first and second non-contact switches 14a, 14b, 14c, 16a, 16b, 16c is open, because when any of the first and second non-contact switches is open, the resistance of the corresponding electrical path 22, 24 increases (because the current must then travel through the corresponding first or second bypass resistor 18a, 18b, 18c, 20a, 20b, 20c).

[0052] Furthermore, the resistances of the first and second bypass resistors 18a, 18b, 18c, 20a, 20b, 20c are selected to enable the monitoring device 26 to determine which particular hoistway doors is open. For example, the first and second bypass resistors 18c, 20c associated with the upper hoistway door 10c have a resistance of 1 kΩ, the first and second bypass resistors 18b, 20b associated with the middle hoistway door 10b have a resistance of 2 kΩ and the first and second bypass resistors 18c, 20c associated with the lower hoistway door 10c have a resistance of 4 kΩ. The monitoring device 26 may thus use the measured resistance of the first or second electrical paths 22, 24 to determine which of the switches 14a, 14b, 14c, 16a, 16b, 16c (and thus which corresponding hoistway door(s) 10a, 10b,10c) is open according to the following table, presuming a baseline resistance (with all switches closed) of approximately 0Ω:

TABLE-US-00001 Resistance measurement Open hoistway door ~0 Ω None 1 kΩ Upper (10c) 2 kΩ Middle (10b) 3 kΩ Upper (10c) and middle (10b) 4 kΩ Lower (10a) 5 kΩ Upper (10c) and lower (10a) 6 kΩ Upper (10c) and middle (10a) 7 kΩ All

[0053] For example, in the scenario illustrated in FIG. 2, the upper hoistway door 10c is open (e.g. due to the elevator car having stopped at the landing 8 to allow passengers on/off, or for any other reason such as a fault or a mechanical failure). The first and second non-contact switches 14c, 16c of the corresponding set of non-contact switches 12c both open as they are designed to do. As a result, the resistances of the first and second electrical paths 22, 24 both increase to ˜1 kΩ. This is measured by the monitoring device 26 which consequently determines that the upper hoistway door 10c is open and automatically halts operation of the elevator car 4.

[0054] In the scenario illustrated in FIG. 3, the lower hoistway door 10a is open, but only the first non-contact switch 14a of the corresponding set 12a properly detects this and opens. The second non-contact switch 16a remains closed (e.g. due to a fault with the non-contact switch 16a). The monitoring device 26 measures the resistance of the first electrical path 22 to be 4 kΩ, but the resistance of the second electrical path 24 remains at ˜0Ω. The monitoring device 26 determines that the lower hoistway door 10a is open and automatically halts operation of the elevator car 4 based on detection of the open switch 14a, but also detects and reports that the second non-contact switch 16a may be faulty.

[0055] In another example which is not illustrated, the first and second non-contact switches 14a, 14b, 14c, 16a, 16b, 16c are laid out as shown in FIG. 1 and connected to the monitoring device 26 in the same manner, but the first and second bypass resistors 18a, 18b, 18c, 20a, 20b, 20c are omitted. This simpler embodiment still provides the redundancy of the first non-contact switch 14a and the second non-contact switch 16a in each set, with the diagnostic capability to determine a faulty switch, and with the simplicity of only two electrical paths for the monitoring device 26 to monitor, but does not provide the more detailed diagnostics of which door or switch may be open.

[0056] FIG. 4 shows another elevator system 102 comprising an elevator car 4 that is driven to move in a hoistway 6 between a plurality of landings 8. Hoistway doors 10a, 10b, 10c on each landing 8 open to provide access to the elevator car 4 but otherwise remain closed to prevent unsafe access to the hoistway 6. As with the example illustrated in FIGS. 1-3, the elevator system 102 comprises a plurality of sets of non-contact switches 112a, 112b, 112c, each set arranged to monitor the state of a respective hoistway door 10a, 10b, 10c. Each set of non-contact switches 112a, 112b, 112c comprises a first non-contact switch 114a, 114b, 114c, a second non-contact switch 116a, 116b, 116c and a bypass resistor 117a, 117b, 117c, all connected in parallel.

[0057] In this example, each first non-contact switch 114a, 114b, 114c is connected in series with a first resistor 118a, 118b, 118c and each second non-contact switch 116a, 116b, 116c is connected in series with a second resistor 120a, 120b, 120c. The sets of non-contact switches 112a, 112b, 112c are connected in series to form an electrical path 122. A monitoring device 126 is arranged to measure an electrical property of the electrical path 122 (in this example, a resistance of the electrical path 122). The monitoring device 126 is thus able to detect when any one of the first and second non-contact switches 114a, 114b, 114c, 116a, 116b, 116c opens by measuring the corresponding increase in the resistance of the electrical path 122. As each set 112a, 112b, 112c comprises three resistors in parallel (e.g. the first resistor 118a, the second resistor 120a and the bypass resistor 117a of the first set 112a), the opening of either switch (e.g. the first non-contact switch 114a or second non-contact switch 116a) will remove one resistor from the parallel arrangement, thereby increasing the overall resistance of the set (e.g. 112a).

[0058] Furthermore, the resistances of the first and second resistors 118a, 118b, 118c, 120a, 120b, 120c and the bypass resistors 117a, 117b, 117c are selected to enable the monitoring device 126 to determine which particular hoistway door 10a, 10b, 10c is open—i.e. such that each combination of open and closed hoistway doors 10a, 10b, 10c corresponds to a unique resistance of the electrical path 122.

[0059] In use, the monitoring device 126 measures the resistance of the electrical path 122. As shown in FIG. 5, when the upper hoistway door 10c opens, the corresponding first and second non-contact switches 114c, 116c open and the resistance of the electrical path 122 changes accordingly. The monitoring device 126 thus detects that a door being open and, by measuring the resistance of the electrical path 122, identifies that it is the upper hoistway door 10c that is open.

[0060] Because the first and second non-contact switches 114c, 116c are connected in series with first and second resistors 118c, 120c, even if one of the non-contact switches 114c, 116c is faulty (i.e. it does not open when the hoistway door 10c opens), the resistance of the path 122 will still change. The monitoring device 126 can thus detect that a door is open despite the fault (even if it cannot identify which particular door is open).

[0061] In some examples, the resistances of the first and second resistors 118a, 118b, 118c, 120a, 120b, 120c and the bypass resistors 117a, 117b, 117c are chosen such that each combination of open and closed non-contact switches 114a, 114b, 114c, 116a, 116b, 116c corresponds to a unique resistance of the electrical path 122. This enables the monitoring device 126 to detect and identify a specific open door even if one of the non-contact switches corresponding to that door is faulty. This may also allow the monitoring device 126 to identify faulty non-contact switches.

[0062] FIG. 6 shows another elevator system 202 which uses AC monitoring to detect and identify open hoistway doors.

[0063] The elevator system 202 comprises an elevator car 4 that is driven to move in a hoistway 6 between a plurality of landings 8. Hoistway doors 10a, 10b, 10c on each landing 8 open to provide access to the elevator car 4 but otherwise remain closed to prevent unsafe access to the hoistway 6. As with the examples illustrated in FIGS. 1-5, the elevator system 202 comprises a plurality of sets of non-contact switches 212a, 212b, 212c, each set arranged to monitor the state of a respective hoistway door 10a, 10b, 10c.

[0064] Each set of non-contact switches 212a, 212b, 212c comprises a non-contact switch 214a, 214b, 214c and a bypass filter circuit connected in parallel with the non-contact switch 214a, 214b, 214c. Each bypass filter circuit comprises a resistor 218a, 218b, 218c and an inductor 220a, 220b, 220c connected in series. In other examples (not illustrated) a bypass filter circuit may comprise a single inductor, a resistor connected in parallel with an inductor or a capacitor, or any other combination of resistors, inductors and/or capacitors (or other components) suitable for providing a set of non-contact switches with a unique AC electrical property.

[0065] All of the non-contact switches 214a, 214b, 214c are connected in series to form an electrical path 222, which is connected to a monitoring device 226. The monitoring device 226 is arranged to measure an AC electrical property of the electrical path 222. In this example, the monitoring device 226 is arranged to measure the time it takes for a short electrical pulse to propagate through the electrical path 222 (i.e. the pulse delay time). This allows the monitoring device 226 to detect when any one of the non-contact switches 214a, 214b, 214c is open, because when any of the non-contact switches 214a, 214b, 214c is open the impedance of the electrical path 222 (and thus the pulse delay time) changes.

[0066] The resistances of the resistors 218a, 218b, 218c and the inductances of the inductors 220a, 220b, 220c are selected such that each combination of open and closed doors corresponds to a unique pulse delay time. This allows the monitoring device 226 to detect and identify open doors 10a, 10b, 10c by measuring the pulse delay time of the electrical path 222.

[0067] In some examples, the monitoring device 226 has two modes of operation. The first mode is a passive detection mode in which the monitoring device 226 measures a DC resistance of the electrical path 222 (e.g. by applying a known voltage to the electrical path 222 and measuring current flow through the electrical path 222). The second mode is an active localization mode, in which the monitoring device 226 measures the pulse delay time of the electrical path 222 (e.g. measuring the time it takes for a short electrical pulse to propagate through the electrical path 222).

[0068] The monitoring device 226 normally operates in the passive detection mode. If any of the non-contact switches 214a, 214b, 214c opens (i.e. if the corresponding hoistway door 10a, 10b, 10c opens), the resistance of the electrical path changes (because current must now pass through the corresponding resistor 218a, 218b, 281c of the bypass filter circuit. This change is easily detected by the monitoring device 226. The monitoring device 226 may consume little power in the passive detection mode (e.g. by applying only a small voltage applied to the electrical path 222), but the accuracy with which the change in resistance can be measured is limited. Thus, when a change in resistance (i.e. an open door) is detected, the monitoring device 226 switches to the active localization mode, in which the open door can be quickly and accurately identified from the measured pulse delay time which depends on the value of the inductor corresponding to the open door.

[0069] FIGS. 7 and 8 illustrate some alternative arrangements for impedances that can be used with the examples described above. The arrangements illustrated in FIG. 7 are particularly suited for use in the examples of FIGS. 1, 2, 3 and 6. The arrangements illustrated in FIG. 8 are particularly suited for use in the examples of FIGS. 4 and 5. It will however be appreciated that these examples are merely illustrative and are not limiting. Other arrangements are also possible.

[0070] While the disclosure has been described in detail in connection with only a limited number of examples, it should be readily understood that the disclosure is not limited to such disclosed examples. Rather, the disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the scope of the disclosure. Additionally, while various examples of the disclosure have been described, it is to be understood that aspects of the disclosure may include only some of the described examples. Accordingly, the disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.