SAFETY MONITORING DEVICE, AND METHOD FOR MONITORING THE SAFETY OF AN ELEVATOR SYSTEM

Abstract

A safety monitoring device of an elevator system having a shaft extending over at least two floors has a safety circuit with door contact switches being closed or opened accordingly when a respective shaft door is closed or opened. The door switches form an electrical series circuit that is electrically broken to block the elevator car from moving when any of the door switches is opened. The monitoring apparatus has at least one bypass switch that actuates a first door switch for a first shaft door on a first floor such that, when the elevator car reaches the first floor, the bypass switch bypasses the first door switch to switch the safety circuit independently of the first door switch. A monitoring means of the monitoring apparatus monitors the switching state of the safety circuit and/or of a second door switch for a second shaft door on a second floor.

Claims

1-15. (canceled)

16. A safety monitoring apparatus for an elevator system, the elevator system having a shaft extending over at least two floors, an elevator car adapted to travel in the shaft and the shaft having at least one shaft door on each of the floors, the safety monitoring apparatus comprising: a safety circuit including a door contact switch for each of the shaft doors, each of the door contact switches being closed or opened accordingly when an associated one of the shaft doors is closed or opened; wherein the door contact switches are connected to form an electrical series circuit such that, when one of the door contact switches is opened, the safety circuit is electrically broken to block the elevator car from moving; at least one bypass switch adapted to actuate a first of the door contact switches at a first of the shaft doors on a first of the floors such that, when the elevator car reaches the first floor, the bypass switch bypasses the first door contact switch to make the safety circuit switchable independently of the first door contact switch; and a monitoring means that monitors at least one of a switching state of the safety circuit and a switching state of a second of the door contact switches at a second of the shaft doors on a second of the floors.

17. The safety monitoring apparatus according to claim 16 wherein, while the bypass switch bypasses the first door contact switch, the safety circuit can be electrically broken or closed accordingly by opening or closing the second door contact switch in response to the opening or closing of the second shaft door on the second floor.

18. The safety monitoring apparatus according to claim 16 wherein the bypass switch is fixed to the elevator car.

19. The safety monitoring apparatus according to claim 16 including an individual one of the bypass switch associated with each one of the door contact switches, each of the bypass switches being mounted relative to the associated door contact switch such that the bypass switch bypasses the associated door contact switch when the elevator car reaches a one of the floors having the shaft door to which the associated door contact switch is assigned.

20. The safety monitoring apparatus according to claim 16 wherein the elevator car reaches one of the floors when the elevator car lands on the one floor or reaches an unlocking zone of the one floor, the unlocking zone located at least one of above and below a floor stopping position of the elevator car at the one floor in the shaft, and wherein in the unlocking zone the bypass switch bypasses the door contact switch at the one floor.

21. The safety monitoring apparatus according to claim 16 wherein the monitoring means generates an alarm signal when the safety circuit is broken.

22. The safety monitoring apparatus according to claim 16 including a memory unit that stores as a log an identity of the second door contact when opened and at least one of a time and a duration of a break in the safety circuit.

23. The safety monitoring apparatus according to claim 16 wherein the monitoring means communicates with at least one of an elevator-internal controller of the elevator system, an elevator-external controller of the elevator system, an external controller and a mobile device.

24. The safety monitoring apparatus according to claim 16 including an interconnection with at least one other safety monitoring apparatus, the at least one other safety monitoring apparatus having a same or different numbers of the door contact switches and/or the bypass switch as the safety monitoring apparatus.

25. An elevator system comprising: a shaft extending over at least two floors; an elevator car adapted to travel in the shaft; wherein the shaft has at least one shaft door on each of the floors; and the safety monitoring apparatus according to claim 16 monitoring the elevator system.

26. A method for monitoring a safety of an elevator system having a shaft extending over at least two floors, wherein an elevator car is adapted to travel in the shaft and the shaft has at least one shaft door on each of the floors, the method comprising the steps of: assigning a door contact switch to each of the shaft doors, wherein when one of the shaft doors is opened and closed the assigned door contact switch is opened and closed; forming a safety circuit by electrically connecting the door contact switches in series, wherein the safety circuit is electrically broken when one of the door contact switches is open thereby blocking the elevator car from moving; bypassing a first of the door contact switches assigned to a first of the shaft doors on a first of the floors by a bypass switch when the elevator car reaches the first floor resulting in the safety circuit being switched independently of the first door contact switch; and monitoring by a monitoring means at least one of a switching state of the safety circuit and switching state of a second of the door contact switches assigned to a second of the shaft doors on a second of the floors.

27. The method according to claim 26 wherein, while the first door contact switch is bypassed, the safety circuit is broken or closed accordingly by opening or closing the second door contact switch in response to opening or closing of the second shaft door on a second floor.

28. The method according to claim 26 wherein the elevator car reaches each of the floors by the elevator car landing on the floor or the elevator car reaching an unlocking zone of the floor, wherein the unlocking zone is above and/or below a floor stopping position of the elevator car at the floor in the shaft, and wherein in the unlocking zone the bypass switch bypasses the door contact switch assigned to the floor.

29. The method according to claim 26 including generating an alarm signal when the safety circuit is broken.

30. The method according to claim 26 including storing as a log at least one of an identity of the opened second door contact switch, a time of break in the safety circuit and a duration of the break in the safety circuit.

31. An elevator system comprising: a shaft extending over at least two floors; an elevator car adapted to travel in the shaft; wherein the shaft has at least one shaft door on each of the floors; and a safety monitoring apparatus monitoring the elevator system by the method according to claim 26.

Description

DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1: shows a conventional elevator system with a safety chain, and

[0023] FIGS. 2.1 through 2.3: show an elevator system comprising a safety monitoring device according to the invention.

[0024] The drawings are merely schematic and not true to scale. Like reference signs denote like or equivalent features in the various drawings.

DETAILED DESCRIPTION

[0025] FIG. 1 shows a conventional elevator system 2 which has an elevator car 5 in a shaft 3 having multiple floors 4, with a shaft door 6 being provided on each floor 4. The elevator car 5 has a car door 5a which usually always opens and closes simultaneously with a shaft door 6. A door contact switch 8 is provided on each of the shaft doors 6 and on the car door 5a. This can be used to monitor whether the relevant shaft or car door is currently properly closed or open. The door contact switch 8 is also closed or opened accordingly when the shaft door 6 is closed or opened. All the door contact switches 8 are electrically connected in series and thus form a safety chain 7 of the elevator system 2.

[0026] The safety chain 7 is shown next to the elevator system 2 in a simplified schematic representation. The safety chain 7 is used to monitor a switching state of each door contact switch 8. If one of the door contact switches 8 is opened, the entire safety chain 7 is broken, as a result of which the elevator car 5 is immediately blocked, regardless of whether it is moving or ready to move at that moment.

[0027] A KNET switch 8a is provided outside the shaft 3 on each floor 4. Such a KNET switch 8a can be switched with a special key in order to unlock or lock a door contact switch 8 of a shaft door 6 so that the shaft door 6 can be opened or closed manually.

[0028] In such an elevator system 2, however, it is not possible to monitor, during a stoppage of an elevator car 5 on a floor 4, whether another shaft door 6 on another floor is open or has been opened in the meantime. This could trigger a dangerous situation, in particular during maintenance work, if the elevator car 5 with an open shaft door 6 and the car door 5a is waiting for a first service technician on a floor 4, but a second service technician has opened another shaft door 6 using a KNET switch 8a on another floor and has entered the shaft 3, e.g. the shaft pit, after which he has closed this shaft door 6 again. In this case, a journey by the elevator car 5 could endanger the second service technician in the shaft 3.

[0029] FIGS. 2.1 to 2.3 each show a safety monitoring apparatus 1 according to the invention for an elevator system 2 shown above. A KNET switch is no longer required for this elevator system 2. The safety monitoring apparatus 1 comprises a safety circuit 7, which corresponds to the safety chain 7 in FIG. 1. In this embodiment, the safety monitoring apparatus 1 has a bypass switch 9 which is fixed e.g. to the elevator car 5. As an alternative to this, a bypass switch 9 can be mounted in the shaft 3 next to each door contact switch 8. The bypass switch 9 and a door contact switch 8 can interact in such a way that, when the elevator car 5 reaches a floor 4 and passes the bypass switch 9, the elevator car 5 can activate the bypass switch 9 to bypass a door contact switch 8, as a result of which the corresponding shaft door 6 and the door contact switch 8 are decoupled. In this case, the entire safety circuit 7 remains electrically closed, even if this shaft door 6 is open. A monitoring means 10 of the safety monitoring apparatus 1 monitors the switching state of the safety circuit 7 and/or of a door contact switch 8. The monitoring means 10 can be an electronic control unit. There is also a possibility that the monitoring means 10 is a physical parameter or an electrical signal that represents a switching state of a door contact switch 8 when considering a measuring point in the safety circuit 7 and measuring the parameter or the signal at this measuring point. The monitoring means 10 can communicate with an elevator-internal or elevator-external controller 14 and a mobile device 15 in order to further transmit a monitoring result. This communication can be over a wired or wireless connection.

[0030] FIG. 2.1 shows that the safety monitoring apparatus 1 according to the invention with a closed safety circuit 7 when the elevator car 5 moves between floors 4 e.g. in a normal operating mode. In this case, nowhere is a door contact switch 8 of the shaft door 6 bypassed by the bypass switch 9.

[0031] FIG. 2.2 shows that the safety monitoring apparatus 1 keeps the safety circuit 7 closed while a shaft door 6 is open. When the elevator car 5 lands on a destination or intermediate destination floor, a first door contact switch 8a is opened by simultaneously opening a first shaft door 6a on this floor 4. Since the opened door contact switch 8a is bypassed by the bypass switch 9, there is a continuous current path (not shown) along the safety circuit 7 via the bypass switch 9. Since the car door 5a and the respective shaft doors 6 are always closed or opened simultaneously, the car door 5a is also bypassed when the relevant shaft door 6 is bypassed.

[0032] If a second shaft door 6b on a second floor 4b is opened by someone else, the safety circuit 7 is broken because a second door contact switch 8b is opened. In this case, an alarm signal 12 is generated by the monitoring means 10 in order to warn a service technician (not shown) about the safety circuit 7 being broken. The alarm signal 12 can be sent as an electronic, acoustic, optical and/or vibrating signal and can also be sent to a mobile device (e.g. smartphone) 15 of the service technician in front of or in the elevator car 5. It can also be determined which door contact switch 8 or which shaft door 6 has been opened.

[0033] A memory unit 13 of the safety monitoring device 1 is provided, on which a number or identity of the opened second door contact switch 8b, the time and the duration of the break of the second door contact switch 8b or the safety circuit 7 can be stored as a log. It is then possible to conclude that there is a technical fault or unauthorized entry into the shaft 3.

[0034] FIG. 2.3 shows that there is an unlocking zone 11 in the shaft 3 which is close to a floor stopping position of the elevator car 5 with respect to the relevant floor 4 and is typically approximately 20 to 35 cm above and below the floor stopping position. Depending on whether the elevator car 5 is reaching or leaving a floor 4, the unlocking zone 11 can also be designated as an entry or exit zone. A sensor system or a position determination is used to determine whether the elevator car 5 is in the unlocking zone. For example, information about a current position of the elevator car 5 in the shaft 3 can be determined using a magnetic tape extending vertically along the shaft 3 and a magnetic tape reader mounted on the elevator car 5.

[0035] When the elevator car 5 travels into the unlocking zone 11 and the elevator car 5 is thus very close (e.g. <30 cm) to a floor stopping position, a corresponding door contact switch 8a of the shaft door 6a is unlocked so that the shaft door 6a can be opened before the elevator car 5 actually reaches its floor stopping position. Accordingly, the elevator car 5 may already start moving with an open or half-closing shaft door 6a. In this case, the open door contact switch 8a is bypassed by the bypass switch 9, and the safety circuit 7 remains closed. The experience of traveling with the elevator system 2 can thus be optimized, e.g. leveling of a landing for the elevator system 2 can be provided in order to accelerate door opening processes in this way and reduce the length of stay on the floor.

[0036] Finally, it should be noted that terms such as “comprising,” “having,” etc., do not preclude other elements or steps and terms such as “a” or “an” do not preclude a plurality. Furthermore, it should be noted that features or steps which have been described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above.

[0037] In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.