ELEVATOR SAFETY DEVICES

Abstract

An elevator safety device 16 for monitoring a landing door 10 of an elevator system 2. The elevator system 2 includes a landing door sensor 14 arranged to detect a state of the landing door 10. The elevator safety device 16 includes a power source 20 arranged to power the landing door sensor 14 independently of a power supply 19 of the elevator system 2 and a memory 22 arranged to record a state of the landing door 10 detected by the landing door sensor 14 when the landing door sensor 14 is powered by the power source 20.

Claims

1. An elevator safety device (16) for monitoring a landing door (10) of an elevator system (2), the elevator system (2) comprising a landing door sensor (14) arranged to detect a state of the landing door (10), the elevator safety device (16) comprising: a power source (20) arranged to power the landing door sensor (14) independently of a power supply (19) of the elevator system (2); and a memory (22) arranged to record a state of the landing door (10) detected by the landing door sensor (14) when the landing door sensor (14) is powered by the power source (20).

2. The elevator safety device (16) of claim 1, arranged to power the landing door sensor (14) using the power source (20) when the power supply (19) of the elevator system (2) is interrupted and to disconnect the landing door sensor (14) from the power source (20) when the power supply (19) of the elevator system (2) is active.

3. The elevator safety device (16) of claim 1, wherein the power source (20) comprises a battery, a capacitor or a supercapacitor.

4. The elevator safety device (16) of claim 1, arranged to report the recorded state of the landing door (10) to an elevator controller (18) of the elevator system (2) following an interruption to the power supply (19) of the elevator system (2).

5. The elevator safety device (16) of claim 4, comprising a microcontroller (24) arranged to act as an interface between the memory (22) and the elevator controller (18).

6. The elevator safety device (16) of claim 1, wherein the memory (22) is arranged to record a single data point that indicates if the landing door (10) has opened at any point since the memory (22) was last reset.

7. The elevator safety device (16) of claim 1, wherein the memory (22) comprises a non-volatile memory,

8. The elevator safety device (16) of claim 1, wherein the power source (20) is arranged to be connected in series with the landing door sensor (14).

9. The elevator safety device (16) of claim 1, wherein the memory (22) is arranged to be connected in series with the landing door sensor (14).

10. An elevator system (2) comprising: a landing door (10); a landing door sensor (14) arranged to detect a state of the landing door (10); a power supply (19) arranged to power said elevator system (2); an elevator controller (18) arranged to control the elevator system (2); and the elevator safety device (16) as claimed in claim 1, arranged to monitor said landing door (10).

11. The elevator system (2) of claim 10, wherein the elevator controller (18) is arranged to control the elevator system (2) according to the state of the landing door (10) recorded by the memory (22).

12. The elevator system (2) of claim 11, wherein the elevator controller (18) is arranged to initiate an inspection mode if the memory (22) indicates that landing door (10) has been opened and to initiate a normal operational mode if the memory (22) indicates that the landing door (10) has not been opened.

13. The elevator system (2) of claim 11, wherein the elevator controller (18) is arranged to receive information from the landing door sensor (14) independently of the elevator safety device (16), and to control the elevator system (2) according to information received from the landing door sensor (14) independently of the elevator safety device (16).

14. The elevator system (2) of claim 11, wherein: the landing door sensor (16) comprises a switch (16) which completes an electrical connection between a first electrical terminal (28) and a second electrical terminal (30) when the landing door (10) is closed, and which breaks said electrical connection when the landing door (10) is open; and the power source (20) is arranged to be connected to the first terminal (28) of the switch (16); and the memory (22) is arranged to be connected to the second terminal of the switch (16).

15. The elevator system (2) of claim 11, comprising: a plurality of landing doors (10); a plurality of landing door sensors (14), each landing door sensor (14) being arranged to detect a state of a respective landing door (10); and a first elevator safety device (16) arranged to monitor a first set of the landing doors (10) and a second elevator safety device (16) arranged to monitor a second set of the landing doors (10).

Description

DRAWING DESCRIPTION

[0034] One or more non-limiting examples will now be described, by way of example only, and with reference to the accompanying figures in which:

[0035] FIG. 1 is a schematic view of an elevator system according to an example of the present disclosure; and

[0036] FIG. 2 is a schematic view of part of the elevator safety system of the elevator system shown in FIG. 1.

DETAILED DESCRIPTION

[0037] As shown in FIG. 1, an elevator system 2 comprises an elevator car 4 that travels in a hoistway 6 to transport passengers and/or cargo between landings 8 in a building. The hoistway 6 comprises a pit area 7 below the lowest landing 8.

[0038] Each landing 8 features a landing door 10, which allows access to the elevator car 4 when it is adjacent the landing 8, and to the hoistway 6 itself when the elevator car 4 is not adjacent the landing 8.

[0039] The elevator system 2 comprises an elevator safety system 12, comprising a plurality of landing door switches 14, a plurality of elevator safety devices 16 and an elevator controller 18. Each landing door switch 14 detects whether a corresponding landing door 10 is open or closed. The elevator controller 18 is connected to the landing door switches 14 via a landing door sensing circuit 15. The elevator system 2 is powered by a power supply 19.

[0040] FIG. 2 shows part of the elevator safety system 12 in more detail. FIG. 2 shows one of the landing door switches 14, an elevator safety device 16 and the elevator controller 18. The landing door switch 14 completes an electrical connection between a first electrical terminal 28 and a second electrical terminal 30 when the landing door 10 is closed, and breaks said electrical connection when the landing door 10 is open.

[0041] The elevator safety device 16 comprises a battery 20, a non-volatile memory 22 and a microcontroller 24. The battery 20 is connected to the first terminal 28 of the landing door switch 14 via a switch 26. The non-volatile memory 22 is connected to the second terminal 30 of the landing door switch 14. The microcontroller 24 is powered by the battery 20 and is in communication with the elevator controller 18.

[0042] During normal operation, the elevator car 4 moves between the landings 8 carrying passengers and/or cargo. It may occasionally be necessary to access the hoistway 6. For instance, an elevator technician may wish to access the pit area 7 of the hoistway 6 to perform a maintenance operation. To do so, the technician opens the lowest landing door 10 whilst the elevator car 4 is elsewhere and climbs into the pit area 7.

[0043] The elevator controller 18 detects that the lowest landing door 10 is open based on a signal from the lowest landing door switch 14 (via the landing door sensing circuit 15). The elevator car 4 is not adjacent that landing door 10, so the elevator controller 18 activates an inspection mode which limits the speed of operation of the elevator car 4 and prevents the elevator car 4 from moving into the pit area 7. This ensures that the technician can perform the maintenance operation in the pit area 7 safely. When the technician leaves the pit area 7, they manually indicate to the elevator controller 18 that they have left the hoistway 6, and normal operation is resumed.

[0044] If the elevator system 2 loses power (e.g. due to an unplanned power cut or an unplanned power outage), the elevator controller 18 can no longer actively monitor the state of the landing doors 10 via the landing door sensing circuit 15. Therefore, the microcontroller 24 monitors the power supply 19 (e.g. via the elevator controller 18) and when the microcontroller 24 detects an interruption in the power supply 19 it resets the memory 22 and closes the switch 26, connecting the battery 20 to the landing door switch 14. A small direct current flows through the landing door switch 14.

[0045] If the landing door switch 14 opens (i.e. if the corresponding landing door 10 opens) whilst the power supply 19 is interrupted (i.e. whilst the battery 20 is connected to power the landing door switch 14), the direct current through the switch 14 is interrupted. This causes the non-volatile memory 22 to record that the landing door 10 has been opened. For instance, the non-volatile memory 22 may record a single data point that the door has been opened since the memory 22 was last reset.

[0046] When power to the elevator system 2 is restored, the microcontroller 24 reads the contents of the non-volatile memory 22 and sends it to the elevator controller 18. This happens for all of the elevator safety devices 16. The elevator controller 18 is thus informed if any of the landing doors 10 were opened whilst the power supply 19 was interrupted. If the contents of the memories 22 indicate that any of the landing doors 10 were opened during the interruption of the power supply 19, the elevator controller 18 restarts operation of the elevator system 2 in the inspection mode. However, if the memories 22 indicate that none of the landing doors 10 were opened during the interruption, the elevator controller 18 activates full operation mode immediately without needing any manual input.

[0047] 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.