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(11) | EP 4 474 330 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | ELEVATOR AND METHOD FOR DEMONSTRATING OPERATION OF ELEVATOR SAFETY SYSTEM |
| (57) An elevator (100), comprising: an elevator car (10) adapted to transfer passengers
and/or cargo between landing floors (30) in an elevator shaft (1); an elevator hoisting
machinery (5) adapted to move the elevator car; an elevator controller (110) configured
to control elevator operation in normal operation mode; and a safety system (120)
configured to: receive safety information from a plurality of safety sensors (20),
detect a safety-related problem based on safety information received from at least
one of the safety sensors; wherein the elevator controller (110) is configured to
execute a normal stop to make elevator car (10) to stop or to hold the car standstill
in the elevator shaft (1); and wherein, in case a safety-related problem was detected,
the safety system (120) is configured to execute a safety stop to bring the elevator
to a safety state, which safety stop is configured to override operation of the elevator
controller (110); wherein the elevator controller (110) is configured to: determine
that one or more predetermined operational conditions for a safety stop demonstration
test are fulfilled, and in response to the determination, deactivate said normal stop,
to demonstrate operation of the safety stop. A method for demonstrating operation
of an elevator safety system (120).
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FIELD OF THE INVENTION
[0001] The invention relates to an elevator and a method for demonstrating operation of an elevator safety system.
BACKGROUND OF THE INVENTION
[0002] An elevator may have an elevator controller controlling elevator operation in a normal operation mode, to transfer passengers and/or cargo between landing floors. The elevator may also have a safety system, which may comprise an electronic safety controller. The safety controller may comprise a processing unit and an I/O circuitry in connection with safety contacts and/or other sensors, such as limit switches, position/speed sensors and/or cameras, to monitor elevator operation.
[0003] In case a safety-related problem was detected, such as an overspeed situation of an elevator car or opening of a landing door during an elevator run, the safety controller may execute a safety stop of the elevator. In doing so the safety controller may override the operation of the elevator controller to bring the elevator to a safe state. For example, the safety controller may activate mechanical hoisting machinery brakes and/or interrupt power supply to a hoisting motor to stop movement of the elevator car, irrespective of the operation of the elevator controller.
[0004] For safety reasons it is important to ensure, that the elevator safety system is functioning correctly.
SUMMARY OF THE INVENTION
[0005] The objective of the invention is to bring forward a solution for demonstrating working condition of an elevator safety system.
[0007] It is also brought forward a new method for demonstrating operation of an elevator safety system according to claim 12.
[0008] The elevator comprises an elevator car adapted to transfer passengers and/or cargo between landing floors in an elevator shaft, an elevator hoisting machinery adapted to move the elevator car, and an elevator controller configured to control elevator operation in normal operation mode.
[0009] The normal operation mode refers herein to an elevator service mode wherein elevator passengers and/or goods are transferred between landing floors according to service requests received from elevator passengers by the elevator controller. In the normal operation mode the elevator controller controls the elevator car movement such that it follows a predefined motion profile. In this process the elevator car starts accelerating smoothly from a departure floor and later on decelerates and stops smoothly at a destination floor, such that passengers can safely enter and exit the car. The motion control takes place by an elevator drive unit, which supplies power signals to an elevator hoisting motor of the elevator hoisting machinery.
[0010] Further, the elevator comprises a safety system configured to receive safety information from a plurality of safety sensors, such as limit switches, position/speed sensors and/or cameras.
[0011] According to an embodiment, the safety system comprises a safety processing unit and an I/O circuitry connected to the processing unit and to the safety sensors. According to an embodiment, the safety system comprises an electronic safety controller comprising the safety processing unit.
[0012] To make the elevator car to stop or to hold the elevator car standstill in the elevator shaft, such as upon arrival at the destination floor, the elevator controller executes a normal stop.
[0013] In case the safety system detects a safety-related problem based on safety information received from the safety sensors, the safety system executes a safety stop, which overrides operation of the elevator controller to bring the elevator to a safe state.
[0014] In the normal stop the elevator controller generates one or more control signals activating hoisting machinery brakes and interrupting power supply of the elevator hoisting motor. In the safety stop the safety controller generates at least one safety stop signal. In response to said at least one safety stop signal a safe brake control SBC, and a safe torque off STO, electronic safety functions will be activated. In active state the SBC will cause activation of the hoisting machinery brakes and the STO will cause interrupting the power supply of the elevator hoisting motor. The SBC and the STO are designed such that in active state they will override any control signals of the elevator controller.
[0015] According to an embodiment, the SBC function is configured to cause activation of the hoisting machinery brakes such as to interrupt a power supply that supplies current to electromagnets of the hoisting machinery brakes.
[0016] According to an embodiment, the STO function is configured to cause interrupting power supply of the elevator hoisting motor. According to an embodiment, the STO function is configured to disable control of (at least a subset of) power transistors of the drive unit.
[0017] In case the elevator controller receives a request for a safety stop demonstration test, it can deactivate the normal stop, such that it will not cause stopping of elevator car during the demonstration test. Operation of the safety stop can then be demonstrated by causing on purpose a safety-related problem (such as pressing a stop button during an elevator run) that triggers a safety stop by the safety system. Consequently, possible operational anomalies of the safety stop function may be detected in a reliable way.
[0018] According to an embodiment, said request for the safety stop demonstration test is generated on-site via a manual operating interface or a mobile device. Alternative or additionally, said request may be received from a remote location, such as from an elevator service centre or from a remote server. Said request may also be based e.g. on a predetermined schedule allocated for the safety stop demonstration test.
[0019] By means of the invention elevator safety may be improved, as the safety stop demonstration test provides reliable information of actual working condition of the safety stop function in the elevator safety system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The invention will in the following be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which:
Figure 1 shows an elevator, and
Figure 2 shows a block diagram of some elements of the elevator with a safety system.
DETAILED DESCRIPTION
[0021] Figure 1 schematically illustrates some aspects of an exemplary elevator 100 comprising an elevator car 10 and a hoisting machinery 5 operable to drive the car 10 in an elevator shaft 1, to transfer passengers and/or cargo between landing floors 30.
[0022] The elevator 100 in Figure 1 comprises an elevator controller 110 configured to control elevator operation in normal operation mode. The elevator controller 110 may comprise an elevator control unit and a drive unit, such as a frequency converter.
[0023] In the normal operation mode the elevator controller 110 controls the car 10 movement such that it follows a predefined, such as calculated motion profile. In this process the car starts accelerating smoothly from a departure floor and later on decelerates and stops smoothly at a destination floor, such that passengers can safely enter and exit the car. The motion control takes place by the elevator drive unit, which supplies power signals to an elevator hoisting motor 51 of the elevator hoisting machinery 5.
[0024] The elevator controller 110 generates control commands 5.1; 5.2 needed to drive the hoisting machinery 5 and manages the movement of the car 10. The hoisting machinery 5 comprises the electrical elevator hoisting motor 51 for driving the car 10, as well as hoisting machinery brakes 52 configured to apply to a traction sheave 53 or a rotating axis of the hoisting machinery, to stop movement of the car or hold the car standstill at a landing 30 in the shaft 1. More generally, the elevator comprises at least one mechanical brake 52 to stop movement of the car or hold the car standstill in the shaft 1. The elevator in Figure 1 has hoisting ropes 6 supporting the car 10, running via the traction sheave 53, and connected to a counterweight 7.
[0025] The car 10 is provided with a car door 11 and a car floor 12. The car door 11 comprises a door that may be moved between a closed position and an open position. The car door 11 may be kept locked while the car 10 is moving, unlocked upon the car 10 entering a landing zone located at and close to a landing 30 and opened upon the car 10 stopping at the landing 30. The car door 11 may be closed before the car 10 leaves the landing 30 and locked upon the car 10 exiting the landing zone. The car 10 is provided with a door operator 13 connected to the car door 11 for temporarily coupling the car door 11 to a landing door 31 provided at each landing 30 when the car 10 resides within the landing zone of the landing 30 such that the landing door 31 moves between a closed position and an open position together with the car door 11, thereby allowing passengers to move between the landing 30 and the car 10 when the car 10 is at the landing 30 while preventing the passengers from entering the shaft 1 when the elevator car 10 is not at the landing 30.
[0026] The elevator in Figure 1 comprises safety sensors 20 configured to provide safety information associated with the elevator 100. The safety sensors 20 may comprise e.g. one or more of: a limit switch, a position sensor, a speed sensor, a camera, a motor encoder; a car pulley encoder; a door zone sensor e.g. providing position information of the elevator car 10 in the vicinity of each landing; a measurement strip extending in the shaft next to elevator car trajectory such as an optically or magnetically readable tape extending in the shaft, a car door contact, a safety contact of an elevator safety gear.
[0028] The elevator 100 comprises a safety system 120 configured to receive safety information from a plurality of safety sensors 20. The safety system in Figure 2 comprises a programmable electronic safety controller 60 with a safety processing unit 50, an I/O circuitry 70 associated with the safety processing unit, and one or more sensors 20 associated with the I/O circuitry and adapted to monitor elevator operation. In the safety stop the safety processing unit 50 generates a safety stop signal.
[0029] The safety system 120 receives safety information from a plurality of safety sensors 20, and can detect a safety-related problem based on safety information received from at least one of the safety sensors.
[0030] The elevator controller 110 is configured to execute a normal stop to make elevator car 10 to stop or to hold the car standstill in the elevator shaft 1. The normal stop control signals can be software signals or hardware signals.
[0031] In case a safety-related problem was detected based on safety information received from the safety sensors 20, the safety system 120 executes a safety stop to bring the elevator to a safety state, which safety stop overrides operation of the elevator controller 110. The safety stop happens when the safety system 120 demands stopping, for example, when elevator landing doors 31 are opened while the car 10 is not parked at that floor 30, or when elevator speed exceeds a rated speed. The safety stop may be activated by removing power from the motor 51 and brakes 52.
[0032] Typically, the safety stop is a separate means from normal stop. This means that it is difficult to know if stopping happened by normal stop or safety stop. It could be even so that one of the stopping means does not work at all because it has been bypassed for testing purposes or by incorrect system installation. For example, safety contactors could be powered continuously from mains instead of being supplied by elevator safety chain, or normal stop could be corrupted, malfunctioned or tampered so that stopping happens always by safety stop.
[0033] To ensure, that the elevator safety system is functioning correctly, the elevator is provided with a safety stop demonstration test that can be performed to improve elevator safety.
[0034] The elevator controller 110 is configured to determine that one or more predetermined operational conditions for a safety stop demonstration test are fulfilled, and in response to the determination, deactivate said normal stop, to demonstrate operation of the safety stop.
[0035] In active state of the safety stop demonstration test, the elevator controller 110 determines that one or more predetermined operational conditions for the safety stop demonstration test are fulfilled, and in response to the determination, deactivates the normal stop, to demonstrate operation of the safety stop.
[0036] When the elevator controller 110 receives a request for the safety stop demonstration test, it deactivates the normal stop such that it will not cause stopping of elevator car during the safety stop demonstration test.
[0037] Said request for the safety stop demonstration test may be generated on-site via a manual operating interface or a mobile device. Said request for the safety stop demonstration test may be received from a remote location, such as from an elevator service centre or from a remote server.
[0038] In the normal stop the elevator controller 110 generates one or more control signals 5.1; 5.2 activating hoisting machinery brakes 52 and interrupting power supply of the elevator hoisting motor 51.
[0039] In response to said safety stop signal a safe brake control SBC, and a safe torque off STO, electronic safety functions comprised by the safety system 120 will be activated. In active state the SBC will cause activation of the hoisting machinery brakes 52 and the STO will cause interrupting the power supply of the elevator hoisting motor 51. The SBC and the STO are designed such that in active state they will override any control signals of the elevator controller 110.
[0040] According to an embodiment, the elevator controller 110 executes the normal stop in case a predefined stopping criteria of the elevator car 10 is not fulfilled during the safety stop demonstration test.
[0041] According to an example embodiment, after receiving the request for the safety stop demonstration test, the elevator is switched to RDF/service mode after which the new drive commissioning test, for example called "Safety means stopping demonstration test", can be selected from a test menu of the elevator. According to an embodiment, by selecting this test, all software-based normal stop functions are overridden during the next run. During this test run, the elevator can be stopped using safety means by pressing STOP button, activating RDF mode, or activating other equivalent method to cause brake 52 stop request. If a safety means was bypassed, for example safety relays, the drive software may monitor the elevator speed and stop the test if speed is not going to zero within a second in order to avoid hazardous situation. According to an embodiment, a "Test failed" message is displayed in this case. If everything works correctly, the elevator stops immediately by the safety means and give a "Passed safety stop demonstration test" result for the operator.
[0042] According to an embodiment, the safety stop demonstration test is performed during elevator safety inspection. According to an embodiment, the safety stop demonstration test is mandatory when elevator safety inspection is performed.
[0043] The use of the invention is not limited to the embodiments disclosed in the figures. It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.
1. An elevator (100), comprising:
an elevator car (10) adapted to transfer passengers and/or cargo between landing floors (30) in an elevator shaft (1);
an elevator hoisting machinery (5) adapted to move the elevator car;
an elevator controller (110) configured to control elevator operation in normal operation mode; and
a safety system (120) configured to:
receive safety information from a plurality of safety sensors (20),
detect a safety-related problem based on safety information received from at least one of the safety sensors;
wherein the elevator controller (110) is configured to execute a normal stop to make elevator car (10) to stop or to hold the car standstill in the elevator shaft (1);
and wherein the safety system (120) is configured to:
in case a safety-related problem was detected, to execute a safety stop to bring the elevator to a safety state, which safety stop is configured to override operation of the elevator controller (110);
wherein the elevator controller (110) is configured to:
determine that one or more predetermined operational conditions for a safety stop demonstration test are fulfilled; and
in response to the determination, deactivate said normal stop, to demonstrate operation of the safety stop.
2. The elevator according claim 1, wherein the safety system (120) comprises:
a safety processing unit (50);
an I/O circuitry (70) associated with the safety processing unit;
one or more sensors (20) associated with the I/O circuitry and adapted to monitor elevator operation.
3. The elevator according to claim 2, wherein in the safety stop the safety processing
unit (50) is configured to generate at least one safety stop signal.
4. The elevator according to any of preceding claims, wherein a safety sensor (20) is
selected from: a limit switch, a position sensor, a speed sensor, a camera, a motor
encoder, a car pulley encoder, a door zone sensor, a car door contact, a safety contact
of an elevator safety gear, an optically or magnetically readable tape.
5. The elevator according to any of preceding claims, wherein in the normal stop the
elevator controller (110) is configured to generate: a brake control signal (5.2)
for activating a mechanical brake (52) of an elevator hoisting motor (51) comprised
by the elevator hoisting machinery (5); and a motor control signal (5.1) for interrupting
power supply of the elevator hoisting motor.
6. The elevator according to any of preceding claims, wherein the safety system (120)
comprises electronic safety functions: a safe brake control SBC, and a safe torque
off STO, which are configured to be activated in response to a safety stop signal.
7. The elevator according to claim 6, wherein in active state the SBC is configured to
cause activation of hoisting machinery brakes (52), and in active state the STO is
configured to cause interrupting power supply of the elevator hoisting motor (51).
8. The elevator according to claim 6 or 7, wherein in active state the SBC is configured
to override any control signals of the elevator controller (110) and in active state
the STO is configured to override any control signals of the elevator controller (110).
9. The elevator according to any of preceding claims, wherein the elevator controller
(110) is configured to execute the normal stop in case a predefined stopping criteria
of the elevator car (10) is not fulfilled during the safety stop demonstration test.
10. The elevator according to any of preceding claims, wherein in case a request for a
safety stop demonstration test is received by the elevator controller (110), it is
configured to deactivate the normal stop such that it will not cause stopping of elevator
car during the safety stop demonstration test.
11. The elevator according to claim 10, wherein the request for a safety stop demonstration
test is based on a predetermined schedule allocated for the safety stop demonstration
test.
12. A method for demonstrating operation of an elevator safety system (120) in an elevator
(100) according to any of previous claims, the method comprising:
determining by an elevator controller (110) that one or more predetermined operational conditions for a safety stop demonstration test are fulfilled, and
in response to the determination, deactivating by the elevator controller (110) said normal stop, to demonstrate operation of the safety stop.
13. The method according to claim 12, comprising executing the normal stop by the elevator
controller (110) in case a predefined stopping criteria of the elevator car (10) is
not fulfilled during the safety stop demonstration test.
14. The method according to claim 12 or 13, comprising, in case a request for a safety
stop demonstration test is received by the elevator controller (110), deactivating
by the elevator controller the normal stop such that it will not cause stopping of
elevator car during the safety stop demonstration test
15. The method according to claim 14, comprising generating said request for the safety
stop demonstration test on-site via a manual operating interface or a mobile device;
and/or receiving said request from a remote location, such as from an elevator service
centre or from a remote server.