Method for securing an elevator in an elevator system, elevator control unit, elevator system and computer program product

Abstract

The present document discloses a method for securing an elevator in an elevator system (100), an elevator control unit (1100), an elevator system (100) and a computer program product. The method includes detecting (505) a foreign matter in the elevator hoistway during a normal mode of operation, establishing (510) a safety zone of the elevator hoistway (12), where the safety zone (101) is associated with a safety zone speed, a safety distance, and a safety direction, switching (515) an operating mode of the elevator system (100) to a safety zone mode, determining (520) that the elevator car (10) is in the safety zone, and determining (520) that the elevator car (10) is in the safety zone. And allowing (525) movement of the elevator car (10) in the safe zone (101) in the safe direction at a speed that does not exceed the safe zone speed.

Description

Technical Field

[0001] The present invention relates generally to elevators. In particular, but not exclusively, the present invention relates to methods and systems for ensuring the safety of elevators. Background Art

[0002] There are elevators with a short headroom or roof and / or a short pit or bottom of the elevator hoistway. In such elevators, elevator maintenance operations such as those related to service and inspection of components in the hoistway are performed from inside the elevator car, for example through an open car service entrance roof, floor or wall, or through an open car door. In these cases, a permanent and natural refuge space is provided inside the elevator car, since there is no free headroom space on the car roof, nor refuge space and / or free pit space at the bottom of the hoistway. Therefore, a car inspection drive can be performed from inside the elevator car with an open car roof as a service entrance to the hoistway, which is usually above (or below or to the side) of the car.

[0003] In the case of an elevator without clearance, access from the landing to the car roof can be disabled or prevented by removing the emergency opening device from the landing doors (e.g. excluding the lowest landing door) and by having enhanced vandalism protection in the landing doors so that it is not possible to manipulate them open if the elevator car is not at the landing. For the residual risk of hoistway intrusion and foreign objects in the hoistway, a detection system can be used on the elevator car roof, which detects whether there is a person on the elevator car roof.

[0004] There are several known solutions for such detection systems, such as light curtain type optical detection systems, detection by a switch based swinging roof, a switch based floating detection platform plate, and a pressure sensitive detection carpet on the roof of the elevator car.

[0005] If the detection system indicates presence detection while the elevator is running, the elevator performs an immediate emergency stop. Of course, this is due to the fact that there is no free space at the top and, depending on the detection system, there is someone at the top of the car, which can be a dangerous situation.

[0006] In practice, it is not possible to access the top of a moving elevator car, but there is always a small risk that the detection system indicates detection for other reasons, such as due to reliability issues related to the detection or some other object on top of the car (e.g. a mouse or bird), or smoke in the case of a light curtain detection system. The result can be that passengers are trapped or stuck in the elevator car if it stops between landings and / or door zones.

[0007] In the event of a person being detected on top of the elevator car, in known solutions all movement of the elevator car is disabled, for example by triggering an anti-creep device. This can result in passengers waiting very long until a licensed maintenance technician arrives on site to drive the elevator car to the next landing by means of a rescue drive function. Summary of the invention

[0008] It is an object of the present invention to provide a method, an elevator control unit, an elevator system and a computer program product for ensuring elevator safety in an elevator system. It is a further object of the present invention that the method, the elevator control unit, the elevator system and the computer program product method at least alleviate the disadvantages of known solutions, such as those associated with prolonged periods of time during which passengers are trapped in the elevator car.

[0009] The objects of the invention are achieved by a method for ensuring elevator safety in an elevator system, an elevator control unit, an elevator system and a computer program product as defined by the respective independent claims.

[0010] According to a first aspect, a method for ensuring elevator safety in an elevator system is provided. The method comprises the following steps:

[0011] - Detection of foreign objects in the elevator shaft during normal operating mode,

[0012] - establishing a safety zone for the elevator shaft, wherein the safety zone is associated with a safety zone speed, a safety distance and a safety direction,

[0013] - Switch the elevator's operating mode to safe zone mode, and

[0014] -The elevator car is allowed to move in the safety direction in the safety zone at a speed not exceeding the safety zone speed.

[0015] The term "foreign object" as used herein refers to any physical object, such as a person, an animal, an open hatch that has been opened into the elevator hoistway, or other physical object that is present inside the elevator hoistway and outside the elevator car, detectable, for example, by sensors, which, however, should not be there during the normal operating mode of the elevator system. Thus, a foreign object is an object that is not desired to be present in the elevator hoistway during the normal operating mode, in particular due to safety reasons. Thus, a foreign object can be a part of the elevator system (e.g. a hatch) or an external object relative to a component of the elevator system.

[0016] The term "normal operation mode" as used herein refers to an operation mode of the elevator system, in which the elevator car serves the landing floors in a normal manner, i.e. in response to elevator commands / calls. In the normal operation mode, at least the critical safety systems function so that the safety of the users is at a sufficiently high level. In the normal operation mode, the safety chain circuit of the elevator system is intact / error-free. As known to those skilled in the art, the safety chain circuit typically includes, for example, a plurality of protection devices.

[0017] In various embodiments, a safety zone can be established based on the position of the elevator car, such as a safe direction relative to the car, or relative to the size of the safety zone relative to the position of the elevator car. In addition, the position of the elevator car near one end of the elevator shaft can be used to define the safety zone.

[0018] The safe zone speed may be equal to or less than the maintenance mode or calibration drive speed of the elevator.

[0019] Additionally or alternatively, the safe direction may be away from a direction in which detection of a foreign object or an open car hatch has been indicated.

[0020] Additionally or alternatively, the safety distance may be the distance between the car and the landing closest to the car in a safe direction.

[0021] Furthermore, the safety zone may include at least one landing or landing floor position in the safety zone.

[0022] In various embodiments, the safety zone may be defined by a limit switch arrangement arranged to the elevator hoistway.

[0023] In various embodiments, the mechanical safety stop can be arranged to prevent the elevator car from moving in a direction toward the end of the shaft when or after leaving the safety zone in the direction of the shaft end.Alternatively or additionally, the method can include pre-triggering an extendable safety stop such as arranged to the elevator car in response to the elevator's operating mode switching to the safety zone mode.

[0024] In various embodiments, the method may include, after allowing movement, automatically moving the elevator car to the landing closest to the elevator car in the safety zone. In addition, the method may optionally further include opening the elevator car door after the automatic movement.

[0025] Additionally, the method may include determining that the elevator car is in a safe zone before allowing movement.

[0026] In some embodiments, the detection of possible foreign objects is based on detecting foreign objects outside the elevator car, such as by a sensor or switch. Alternatively or additionally, the detection of possible foreign objects is based on detecting an open hatch state of the elevator car, such as by a switch arranged to monitor the hatch state.

[0027] In some embodiments, the method may include determining that the possible foreign object is no longer detected before allowing movement.

[0028] According to a second aspect, an elevator control unit is provided. The elevator control unit comprises at least one processor and at least one memory storing at least a portion of a computer program code, such as a non-transitory or non-volatile memory device, wherein the elevator control unit is configured to control the movement of an elevator car. Furthermore, the elevator control unit is configured to perform the method according to the first aspect.

[0029] According to a third aspect, an elevator system is provided. The elevator system comprises at least one elevator car and at least two landings, each of the at least one elevator car being movable in a corresponding elevator shaft. The elevator system further comprises an elevator control unit according to the second aspect.

[0030] In various embodiments, the elevator hoistway may be arranged to include a low top.Alternatively or additionally, the elevator hoistway may be arranged to include a low pit.

[0031] According to a fourth aspect, a computer program product is provided. The computer program product comprises program instructions, such as stored in a non-transitory or non-volatile storage medium, which when executed by an elevator control unit cause the elevator control unit to perform the method according to the first aspect.

[0032] The present invention provides a method for ensuring the safety of elevators in an elevator system, an elevator control unit, an elevator system and a computer program product. The present invention provides advantages over known solutions because it enables the elevator car to move under conditions related to the detection of foreign objects in the elevator shaft and outside the elevator car. The activation of the movement of the elevator car can allow moving to the nearest landing and performing the rescue of passengers in the event of active detection of a person in the elevator shaft.

[0033] Various additional advantages will become apparent to those skilled in the art based on the following detailed description.

[0034] The terms "first," "second," and the like are used herein to distinguish one element from other elements and do not particularly prioritize or rank them unless explicitly stated otherwise.

[0035] The exemplary embodiments of the present invention presented herein should not be interpreted as limiting the applicability of the appended claims. The verb "comprise" is used herein as an open-ended limitation, which does not exclude the presence of unlisted features. Unless explicitly stated otherwise, the features recited in the dependent claims may be freely combined with each other.

[0036] The novel features which are believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Some embodiments of the invention are illustrated by way of example and not limitation in the figures of the accompanying drawings.

[0038] Figure 1 An elevator system according to an embodiment of the invention is schematically shown.

[0039] Figure 2 An elevator system according to an embodiment of the invention is schematically shown.

[0040] Figure 3 An elevator system according to an embodiment of the invention is schematically shown.

[0041] Figure 4 The principle of electrical safety control for a safety zone according to an embodiment of the present invention is shown.

[0042] Figure 5 A flow chart of a method according to an embodiment of the present invention is shown.

[0043] Figure 6 A flow chart of a method according to an embodiment of the present invention is shown.

[0044] Figure 7 An elevator control unit according to an embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0045] Figure 1 Schematically illustrated is an elevator system 100 according to an embodiment of the present invention. The elevator system 100, or as can be seen in the figure, an elevator 100 or one of the elevators of the system 100, may include an elevator car 10, which is arranged to move or be movable in an elevator shaft 12. The movement of the elevator car 10 may be achieved, for example, by a hoisting rope or belt 13 connected to a traction sheave 14 or the like, by hydraulic pressure or by a linear motor. In addition, the elevator 100 includes an electric motor 20, which is arranged to operate (such as by rotating its rotor) the traction sheave 14 for moving the elevator car 10, if not substantially directly coupled to the hoisting rope 13. The traction sheave 14 may be directly connected to the shaft of the motor 20 via a mechanical connection 22 or indirectly via a gear. The elevator 100 may include a machine room or be machine room-less, such as having the motor 20 in the elevator shaft 12.

[0046] The elevator 100 may preferably include landings 19 or landing floors, and for example landing floor doors 19A and / or openings, and the elevator car 10 is arranged to move between the landing floor doors 19A and / or openings during normal elevator operation to move people and / or objects between the landings 19.

[0047] In various embodiments, the elevator shaft 12 can be such that when the elevator car 10 is at the bottom and / or top landing 19, there is substantially no space in the shaft 12 for, for example, maintenance personnel to operate. Such an elevator 100, in which both the bottom landing 19 and the top landing 19 are substantially free of free space, can be referred to as a low-pit, low-headroom elevator. In some embodiments, the height of the pit as the bottom of the shaft 12 and / or the headroom as the top of the shaft 12 can be, for example, less than or equal to 2.5 meters or less than 1.5 meters, or even less than 1 meter.

[0048] The elevator 100 may preferably comprise at least one hoisting machinery brake 16, which is configured to block or preferably prevent the movement of the motor 20 (i.e. its rotor) directly or via the traction sheave 14 or its parts and / or the traction sheave 14 or its parts therebetween. In addition, the elevator 100 may comprise a brake controller 25, which is configured to operate at least one of the at least one hoisting machinery brake 16. The brake controller 25 may also be connected to other elements of the elevator 100, such as the elevator control unit 1000. The brake controller 25 may comprise an actuator (not shown) for operating the brake 16 or at least be connected to such an actuator.

[0049] At least in some embodiments, there may additionally be a counterweight 18, such as known to those skilled in the art of elevators, arranged in connection with the elevator car 10. Furthermore, the elevator 100 may additionally include one or more guide rails 17 arranged into the elevator shaft 12 for guiding the movement of the elevator car 10. The elevator car 10 may include guide shoes, rollers, etc. that move in contact with the guide rails 17.

[0050] The elevator system 100 may also include an elevator drive unit 35, such as including at least a converter unit 30 and preferably an elevator motor 20. The elevator drive unit 35 (such as its converter unit 30) may include an input for receiving absolute position and velocity information of the elevator car 10, such as from an encoder mounted to the elevator car 10 or the elevator motor 20, and a processing unit configured to calculate a motion profile of the elevator car 10. The elevator car 10 may be configured to be driven by the elevator drive unit 35 according to the motion profile. The motion profile may be different based on, for example, whether the elevator system 100 is in a normal operating condition or in a safe zone condition.

[0051] In addition, the converter unit 30 may include or be substantially an inverter or a frequency converter for connecting to the motor 20 and controlling the operation of the motor 20, and a controller connected to the converter unit 30, wherein the controller is configured to operate the converter unit 30 to provide power (signal) such as having a variable voltage and a variable frequency to the winding of the motor 20. For example, the controller may be a separate controller device or included in the converter unit 30. The converter unit 30 may be disposed in the elevator shaft 12.

[0052] Furthermore, the converter unit 30 may be arranged to be fed by a power source 150 , for example from an external grid or mains power source, or a backup power source, such as a battery system.

[0053] In various embodiments, the elevator 100 includes an elevator control unit 1000. The elevator control unit 1000 may be disposed in a door frame of a landing 19 or in a landing door frame. The elevator control unit 1000 may be configured to receive a service request from an elevator passenger, such as via an elevator call request system, and calculate a motion profile of the elevator car 10 to serve the service request. The converter unit 30 controls the elevator hoisting machinery so that the elevator car speed is consistent with the motion profile.

[0054] Figure 2 An elevator system 100 according to an embodiment of the present invention is schematically shown. A safety zone 101 is arranged relative to the position of the elevator car 10 in the elevator shaft 12, such as extending along the longitudinal direction of the shaft 12. The elevator system 100 is configured to allow the elevator car 10 to move at a safe speed (e.g., 0.3m / s) or a check or correction drive speed defined and / or used when the elevator 10 is in a maintenance operation mode (preferably not exceeding the safe (or check or correction) speed) after detecting a foreign object in the elevator shaft 12 (an emergency stop may or may not have been performed), and move a safe distance in a safe direction, for example, moving downward, for example to the next floor station, in the event that a foreign object is detected on the car roof and the free space in the top of the elevator shaft 12 is reduced / missing (i.e., the elevator or elevator system 100 includes a low top or clearance). If the car top detection (CTD) indicates a presence detection or the car top opening monitoring (ROM) indicates that the car top is open, an elevator emergency stop can be initiated. In addition, Figure 2 Elevator car door 11A and elevator car door operating device 11B are shown.

[0055] When the elevator car 10 is in the safety zone 101, at the end of the hoistway 12 (at Figure 2If the car 10 is not in the safe zone 101, i.e. in the unsafe zone 102, or generally outside the safe zone 101, and between the car 10 and the end of the shaft 12, for example, between the top of the car 10 and the roof of the shaft 12 at the top of the shaft 12, there is no or only a small free space 110A or insufficient gap 110B.

[0056] At the end of the safety zone 101, an electrical limiter 103 may be arranged, such as by a limit switch device or software running in the elevator control unit 1000 using absolute position and speed and / or direction feedback from the car 10. After the electrical limiter 103, a mechanical safety limiter 104 may also be arranged, such as a pawl attached to the hoistway wall or a fixed hoistway structure, for capturing the extendable safety limiter 15 (at Figure 2 Schematically shown below the limit stop 104), such as an arm in the car, defines a mechanical limit stop 104B which can be pre-triggered by extending the extendable safety limit stop 15 from the car 10 when a safe zone is established after a CTD or ROM detection indication.

[0057] Detection of the operation of the emergency opening device of, for example, the lowest landing door 19A during elevator operation in the normal operating mode will result in an emergency stop and a corresponding safe zone arrangement at the lower end of the hoistway 12. In this case, the unsafe zone 102 will be located at the very bottom of the hoistway 12, and the safe zone 101 will start at a height that leaves sufficient clearance between the bottom of the car 10 and the hoistway floor.

[0058] In some embodiments, the limit switch device can also be used to set the end of the safety zone 101 into the elevator control unit 1000 during drive setup (such as during elevator commissioning), and thereafter, the safety zone 101 can be feedback controlled and / or established by an absolute position device.

[0059] Figure 3 An elevator system 100 according to an embodiment of the present invention is schematically shown. Figure 3 At least some components of an electrical safety control system according to various embodiments of the present invention are shown. The elevator system 100 may include a detection system for detecting foreign objects on the car roof, such as a CTD or ROM, such as in the car 10 and / or the hoistway 12. The detection system 45 may include a detection sensor, such as a light curtain detection system. The detection system 45 may also include a detection control device 42 connected to the detection sensor. Figure 3Also shown is an optional hatch 48 on top of the elevator car 10, through which, for example, maintenance personnel can climb to the roof of the car 10, i.e. into the elevator shaft 12. There may be a sensor arranged to monitor the position of the hatch 48, i.e. whether the hatch 48 is open or closed. The hatch 48 is Figure 3 is open.

[0060] The elevator system 100 may also include (such as in the car 10 and / or in the hoistway 12) an absolute car position and motion control system 44, which may include a position control unit and a position control sensor. This may preferably be a safety integrity level 3 (SIL3) level car position, speed and direction feedback system that may be controlled by the elevator control unit 1000. The elevator control unit 1000 is preferably arranged to be at least in communication connection with the absolute car position and motion control system 44 and / or a detection system 45 (such as its detection control device 42). The elevator control unit 1000 may include a safety control unit.

[0061] Feedback from the car 10 may be provided from an absolute encoder or tachometer (e.g., located in a guide shoe roller, an overspeed governor (OSG), such as an onboard OSG or an OSG in the hoistway 12 or in headroom with a rope / belt linkage, or located in the diverting pulley 60 or other type of absolute positioning system (e.g., an optical strip reader). The safe zone mode in the elevator control unit 1000 may be set based on a CTD presence detection indication through, for example, an open CTD safety output, or when an opening is detected by a car service entrance roof or lid open monitoring indication.

[0062] In some embodiments, the limit switch device can also be used to set the end of the safety zone 101 into the elevator control unit 1000 during the setting drive (such as during the elevator commissioning), and thereafter, the safety zone 101 can be controlled and / or established by the absolute position device feedback. The limit switch device 50 can include a limit switch 51 and optionally a limit switch partner 52, which is arranged to the elevator shaft 12, such as arranged to the guide rail 17 in the elevator shaft 12. The limit switch device 50 can be used as a reference for self-diagnosis (cross-checking limit switches and absolute position system feedback) of the safety zone 101 in the electrical safety control system.

[0063] As described above, in some embodiments, the electrical safety control system may include a limit switch device 50. The limit switch 51 may be based on a magnetic reader. Then, the limit switch counterpart 52 may be, for example, a magnet at the level of the limit position. However, the limit switch 51 and its counterpart 52 (if any) may also be implemented in various other ways.

[0064] Figure 4The principle of electrical safety control for a safety zone 101 according to an embodiment of the present invention is shown. In the detection control device 42, there may be two separate safety outputs 43. One may be used to pre-trigger the extendable safety limit device 15. The other may be 1) to stop the elevator via a safety circuit, and 2) to set the elevator safety zone mode in the elevator control unit 1000. The control and / or establishment of the safety zone 101 may be based on the car absolute positioning and motion control system 44 and the safety zone limit switch device 50 as a reference. Figure 4 Item 1100 in refers to normal means for driving the elevator car 10, such as with respect to the elevator drive unit 35. Input 129 refers to a reset of the electrical safety control system.

[0065] Figure 5 A flow chart of a method according to an embodiment of the present invention is shown.

[0066] Step 505 refers to detecting a foreign object in the elevator shaft 12 during the normal operating mode. The foreign object may be a person or an animal that should not be present in the elevator shaft 12, i.e., somewhere else than inside the elevator car 10. Alternatively, the foreign object may be an open hatch leading to the elevator shaft 12, such as through a wall of the elevator shaft 12 or an open hatch leading from the elevator car 10 to the elevator shaft 12. For example, an open hatch state detected by a sensor monitoring the position of the hatch 48 indicates that, for example, there may be a person who has entered the elevator shaft 12.

[0067] Step 510 refers to establishing a safety zone 101 of the elevator shaft 12, wherein the safety zone 101 is associated with a safety zone speed, a safety distance, and a safety direction.

[0068] In various embodiments, the safety zone 101 may be established based on the position of the elevator car 10. Furthermore, the safety zone 101 may preferably include at least one landing 19 or landing position in the safety zone 101.

[0069] Step 515 refers to switching the operation mode of the elevator system 100 preferably from the normal operation mode to the safe zone mode.

[0070] Alternatively or additionally, the safety zone 101 may be defined by a mechanical safety limiter 104 arranged to the elevator hoistway 12 .

[0071] In some embodiments, the pre-triggered extendable safety limiter 15 may be arranged to prevent the car from leaving the safety zone 101 in a direction closer to the hoistway end of the car 10 (eg, toward the top or bottom end).

[0072] Step 520 refers to determining that the elevator car 10 is in the safe zone 101 before allowing movement.

[0073] Step 525 refers to allowing the elevator car 10 to move in the safety direction in the safety zone 101 at a speed that does not exceed the safety zone speed.

[0074] In some embodiments, the method may include, after allowing movement, automatically moving the elevator car 10 to the nearest landing included in the safety zone 101. In addition, the method may include opening the elevator car door and / or the landing floor door after the automatic movement of the elevator car 10 when the elevator car 10 has reached the landing 19.

[0075] In some embodiments, the method may include determining that a possible foreign object is no longer detected before allowing any movement. If detection is active, movement may not be allowed as long as detection is active. Movement may be allowed once detection no longer indicates presence or has been reset or deactivated.

[0076] Method execution may be stopped at step 599. The elevator car 10 may now move in a safe direction in the safe zone, for example towards a landing 19 of the elevator 100, such as the closest landing 19 relative to the current position of the elevator car 10.

[0077] In various embodiments, the method may include determining an elevator emergency condition prior to step 510 , such as associated with detecting an object in the elevator hoistway and outside of the elevator car 10 .

[0078] The method may also include detecting possible foreign objects in the elevator shaft 12. For example, the detection may be based on a sensor 42 that detects foreign objects outside the elevator car or a sensor that detects an open hatch state of the elevator car, indicating a possible foreign object in the shaft 12 outside the car 10. Thus, the detection may be based on monitoring the state of a switch, such as a normally open switch, or based on a proximity sensor, a light curtain type optical detection system, a floating detection platform plate with a safety switch that detects compression, or a pressure-sensitive detection carpet on the roof of the elevator car, or a safety switch that detects an open roof panel.

[0079] As described above, the elevator system 100 may include a detection system 45, such as a CTD, and typically also includes means for an immediate emergency stop, such as by the elevator control unit 1000. After detection by the detection system 45 and possible execution of an emergency stop, the electrical safety control system turns on the safe zone mode and enables the elevator system 100 to perform an automatic drive of the elevator car 10 at a safe speed (e.g., 0.3 m / s) and in a safe distance in a safe direction to reach the nearest landing 19. Thereafter, the elevator car 100 may be configured to open the car door and the landing door. In addition, the elevator car 10 may stop at a landing 19 (such as a landing door area) as long as the detection of the detection system 45 is preferably deactivated or reset in a non-volatile or non-transitory memory of the electrical safety control system (such as in the elevator control unit 1000).

[0080] Before enabling automatic drive (enabled by the electrical safety control system but executed by the elevator normal device 1100, such as by the elevator drive unit 35), the electrical safety control turns on a safe zone mode in which the elevator car 10 is allowed to move only at a safe speed and up to a safe distance in a safe direction.

[0081] In some embodiments, at least three steps may be performed as a check sequence before activating the safety zone mode. First, determine whether the elevator car 10 is at the landing 19. This may be based on door zone sensors and / or absolute position feedback. Second, determine whether the detection system 45 is still active, for example, whether someone or something may still be on top of the car 10. This may be performed, for example, based on a SIL3 detection control 42 and detection sensors. Third, determine whether the elevator car 10 is in the safety zone 101, such as based on SIL3 horizontal position and movement feedback from the car 44. From this, it can be concluded that there is sufficient free space and clearance available in the elevator shaft 12.

[0082] Figure 6 A flow chart of a method according to an embodiment of the present invention is shown.

[0083] Item 600 refers to the elevator system 100 being in normal operating mode.

[0084] Figure 6 Item 605 may refer to presence detection of a detection system (such as a CTD) associated with a foreign object in the hoistway 12 and opening of a safety circuit when the elevator system 100 or a single elevator of the elevator system 100 is in operation.

[0085] Item 610 may refer to switching the operating mode of the elevator to a safe zone mode.

[0086] Item 610 may include saving the detected activity to a memory of the elevator control unit 1000 , preferably to a non-volatile memory (storage medium).

[0087] Item 610 may also include initiating an emergency stop of elevator 100 .

[0088] Item 610 may also include a pre-trigger extendable safety limit device 15 .

[0089] Item 615 may refer to determining whether the detection system has indicated presence detection for a predetermined duration.

[0090] Item 620 may refer to waiting for the elevator car speed to decrease below a certain speed limit, such as 1.0, 0.5 or 0.1 m / s. That is, the system or at least the control unit 1000 is arranged to monitor the speed and have an idle or waiting period during which the speed of the elevator car 10 is reduced or waiting to be reduced.

[0091] Item 625 may refer to determining whether the elevator car 10 is in the landing door area, or generally at the landing, so that the door of the elevator car 10 can be opened. Figure 6 As can be seen in FIG. 6 , if the elevator car 10 is determined to be in the landing door area, or generally at a landing so that the door of the elevator car 10 can be opened, then item 660 described below can be directly executed.

[0092] Item 630 may refer to determining whether the elevator car 10 is in the safety zone 101. The elevator control unit 1000 may establish the position of the car 10 relative to the end of the hoistway and may consider it to be in the safety zone 101 if the car 10 does not violate any required clearances.

[0093] Item 635 may include determining whether the extendable safety restraint 15 at the car is pre-triggered.

[0094] Item 640 may refer to moving the elevator car 10 by the elevator control unit 1000 at a safe speed toward a landing in the safety zone 101 (preferably the nearest landing) and in a safe direction.

[0095] Item 645 may refer to determining whether the presence detection system again indicates detection while the elevator car 10 is moving.

[0096] Item 650 may refer to determining whether the elevator car 10 has arrived at the landing, continuing with item 630 to determine whether the elevator car 10 is still in the safety zone 101 .

[0097] Item 655 may refer to stopping the elevator car if presence detection is determined in 645 .

[0098] Item 660 may refer to preventing the car from moving and the operating mode from changing to normal operation if the presence detection system has indicated presence detection within a predetermined duration after item 610 or 655, or if the elevator car 10 is at a landing at item 625 or 650 or outside the safety zone at item 630, or if it is determined at item 635 that the extendable safety limit device 15 at the car has not been pre-triggered, until a reset function is performed by a service person or technician at item 665, such as manually at a maintenance panel, to cancel the safety zone mode after verifying that there are no foreign objects in the shaft.

[0099] In response to and / or after the reset, the normal operating mode is or may be restored.

[0100] Figure 7 The elevator control unit 1000 according to an embodiment of the present invention is schematically shown. An external unit 701 can be connected to a communication interface 708 of the elevator control unit 1000. The external unit 701 can include a wireless connection or a connection by a wired manner. The communication interface 708 provides an interface for communicating with the external unit 701 (such as the elevator car 10, the elevator drive unit 35, the brake 16, the door at the landing 19 and / or the elevator car door). There can also be a connection to an external system (such as a laptop or a handheld device). It can also be connected to a database of the elevator 1000 or an external database including information for controlling the operation of the elevator 1000.

[0101] The elevator control unit 1000 may include one or more processors 704, one or more memories 706, volatile or non-volatile or non-transitory, for storing parts of the computer program code 707A-707N and any data values, and possibly one or more user interface units 710. The mentioned elements may be communicatively coupled to each other using, for example, an internal bus.

[0102] The processor 704 of the elevator control unit 1000 is at least configured to implement at least some of the method steps described above. The implementation of the method can be implemented by arranging the processor 704 to execute at least some parts of the computer program code 707A-707N stored in the memory 706, so that the processor 704 and therefore the elevator control unit 1000 implement one or more of the described method steps. Therefore, the processor 704 is arranged to access the memory 706 and retrieve and store any information from the memory 706. For the sake of clarity, the processor 704 refers to any unit suitable for processing information and controlling the operation of the elevator control unit 1000 and other tasks in this article. The operation can also be implemented using a microcontroller solution with embedded software. Similarly, the memory 706 is not limited to a certain type of memory, but any memory type suitable for storing the described multiple pieces of information can be applied in the context of the present invention.

Claims

1. A method for ensuring elevator safety in an elevator system (100), the method comprising: - detecting (505) a foreign object in the elevator shaft during a normal operating mode, - establishing (510) a safety zone of an elevator shaft (12) of the elevator system (100), wherein the safety zone (101) is associated with a safety zone speed, a safety distance and a safety direction, - switching (515) the operating mode of the elevator system (100) to a safe zone mode, - determining (520) that the elevator car (10) is in said safety zone, and - allowing (525) the elevator car (10) to move in the safety zone (101) in the safety direction at a speed not exceeding the safety zone speed.

2. The method according to claim 1, wherein the safety zone (101) is established based on the position of the elevator car (10).

3. The method according to claim 1 or 2, wherein: The safety zone (101) includes at least one landing (19) in the safety zone (101).

4. A method according to any one of claims 1-3, wherein the safety zone speed is equal to or less than the maintenance mode or correction drive speed of the elevator, the safety direction is away from the direction in which a foreign object or an open car hatch has been indicated to have been detected, and the safety distance is the safety distance between the car and the closest landing station in the safety direction.

5. The method according to claim 4, wherein: The detection of the foreign object is based on a sensor indicating a foreign object outside the elevator car (10) or based on a sensor indicating an open hatch state of the elevator car (10).

6. The method according to any one of claims 1 to 5, wherein: The safety zone (101) is defined by a limit switch device (50) arranged in the elevator shaft (12).

7. A method according to any one of claims 1-6, wherein a mechanical safety limit device (104) is arranged to prevent the elevator car (10) from moving in a direction towards the end of the shaft when or after leaving the safety zone (101).

8. The method according to any one of claims 1 to 7, comprising pre-triggering an extendable safety restraint device (15) in response to switching the operation mode of the elevator (100) to the safe zone mode.

9. The method according to any one of claims 1 to 8, comprising automatically moving the elevator car (10) to a landing closest to the elevator car (10) in the safety zone (101) after allowing (525) the movement.

10. The method of claim 9, further comprising opening an elevator car door after the automatic moving.

11. The method according to any one of claims 1 to 10, comprising: Before movement is permitted, it is determined that there is no longer any foreign object in the elevator hoistway (12) or an indication of an open hatch status of the elevator car (10).

12. An elevator control unit (1000), comprising: at least one processor (704) and at least one memory (706) storing at least a portion (707A-707N) of a computer program code, wherein the elevator control unit (1000) is configured to control the movement of an elevator car (10), wherein The elevator control unit (1000) is configured to execute the method according to any one of claims 1-11.

13. An elevator system (100) comprising at least one elevator car (10) and at least two landings (19), each of the at least one elevator car (10) being movable in a corresponding elevator shaft (12), characterized in that: The elevator system (100) comprises an elevator control unit (1000) according to claim 12.

14. The elevator system (100) of claim 13, wherein the elevator hoistway (12) is arranged to include a low ceiling and / or a low pit.

15. A computer program product comprising program instructions which, when executed by an elevator control unit (1000), cause the elevator control unit (1000) to perform the method according to any of the preceding claims 1-11.

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