The present invention relates to a warning system for an elevator system and a method for warning a maintenance person of an elevator system.

When proper hoistway/elevator shaft procedures for maintenance of an elevator system are not followed by a technician or maintenance person, who maintenances an elevator system, dangerous situations may occur, which can under unfavorable circumstances lead to injuries of the maintenance person. When the maintenance person opens an elevator shaft door, the maintenance person/technician normally assumes the elevator car to be close to the elevator shaft door sill of the floor, where the elevator shaft door is opened. In particular, when the technician or maintenance person opens an elevator shaft door assuming that the elevator car or the top of the elevator car is near the sill of the floor where the elevator shaft door is opened, but the elevator car is not there, the maintenance person/technician can fall into the elevator shaft/elevator shaft pit causing injuries to the maintenance person. There may be a need for a warning system, which warns a maintenance person reliably when unlocking an elevator shaft door that the elevator car is not near the elevator shaft door sill of the elevator shaft door. Also, there may be a need for a method for warning a maintenance person of an elevator system reliably when unlocking an elevator shaft door that the elevator car is not near the elevator shaft door sill of the elevator shaft door.

Such needs may be met with the subject-matters of the independent claims. Advantageous embodiments are defined in the dependent claims.

According to a first aspect of the present invention, a warning system for an elevator system to warn a maintenance person is proposed, comprising - a position sensor for detecting if an elevator car of the elevator system is at a level of the position sensor in an elevator shaft, - an unlock sensor for detecting an unlocking of a lock of an elevator shaft door which is the next elevator shaft door along the elevator shaft above the position sensor, and - a warning signal generator for generating a warning signal, wherein the warning system is adapted such that the warning signal is generated by the warning signal generator, when the unlock sensor detects the unlocking of the lock of the elevator shaft door which is the next elevator shaft door along the elevator shaft above the position sensor and the position sensor detects the non-presence of the elevator car at the level of the position sensor.

Typically, the warning system warns a maintenance person reliably if the elevator car is not at the height/level of the position sensor. I.e., in general, the warning system warns the maintenance person that the elevator car is not there, where the maintenance person most of the times assumes the elevator car to be. Thus, typically, the maintenance person opening the elevator shaft door is made aware that the elevator car (i.e., a part of the elevator car) is not at the height of the position sensor, e.g., near the elevator door sill. Thus, normally, the danger that the maintenance person falls into the elevator shaft or elevator shaft pit is reduced. Hence, in general, the maintenance person is warned of the danger of falling through the unlocked and opened elevator shaft door into the elevator shaft and is aware of the danger. This way, normally, the safety of the elevator system is increased.

In particular, the position sensor can be mounted at the shaft door sill or a few inches (ca. 5 cm to ca. 20 cm, e.g., ca. 10 cm) below the shaft door sill. This way, typically, the top of the elevator door can be at most a small step for a human below the shaft door sill. Generally, if the elevator car is not near the shaft door sill, the danger of falling through the unlocked and opened elevator shaft door into the elevator shaft can exist.

Typically, the warning signal can trigger different kinds of warning signals for the maintenance person.

According to a second aspect of the present invention, a method for warning a maintenance person of an elevator system is proposed, wherein the method comprises the following steps: - detecting if an elevator car is at a level of a position sensor which is located in an elevator shaft ; - detecting if a lock of an elevator shaft door, which is the next elevator shaft door along the elevator shaft above the position sensor, is being unlocked, and - generating a warning signal, when the unlock sensor detects the unlocking of the lock of the elevator shaft door, which is the next elevator shaft door along the elevator shaft above the position sensor, and the position sensor detects the non- presence of the elevator car at the level of the position sensor.

Generally, this method warns a maintenance person reliably if the elevator car is not at the height/level of the position sensor. I.e., in general, this method warns the maintenance person that the elevator car is not there, where the maintenance person most of the times assumes the elevator car to be. Thus, typically, the maintenance person opening the elevator shaft door is made aware that the elevator car (i.e., a part of the elevator car) is not at the height of the position sensor, e.g., near the elevator door sill. Thus, normally, the danger that the maintenance person falls into the elevator shaft or elevator shaft pit is reduced. Hence, in general, the maintenance person is warned that the elevator car is not at the height/level of the position sensor and warned of the danger of falling through the unlocked and opened elevator shaft door into the elevator shaft and is made aware of the danger. This way, normally, the safety of the elevator system is increased.

Ideas underlying embodiments of the present invention may be interpreted as being based, inter alia, on the following observations and recognitions.

According to an embodiment, the warning system further comprises a vibrating device for causing the lock of the elevator shaft door and/or a key inserted into the lock of the elevator shaft door to vibrate at least partially, wherein the warning system is adapted such that the vibrating device causes the lock of the elevator shaft door and/or the key in the lock to vibrate at least partially when the warning signal is generated by the warning signal generator. Generally, one advantage hereof is that vibrations are felt by the maintenance person when the warning signal is generated, i.e., when the elevator car is not at the height/level of the position sensor while the lock of the elevator shaft door is being opened. Typically, vibrations are a very noticeable signal, which can hardly be ignored. Furthermore, normally, in contrast to acoustic warning signals, which can be overheard due to other noise, talking etc., vibrations felt by the maintenance person cannot be superimposed by other sensory perception such that the vibrations are not noticed by the maintenance person. Therefore, in general, the maintenance person is made aware very reliably that the elevator car is not at the position sensor and of the possible dangers associated with that. Thus, typically, the safety of the elevator system is increased. According to an embodiment, the position sensor comprises optical means for detecting if the elevator car of the elevator system is at the level of the position sensor in the elevator shaft. By this, typically, the position sensor can be technically simple. Normally, this reduces the costs and increases the reliability of the warning system.

According to an embodiment, the warning system is further adapted - for receiving position information about the position of the elevator car in the elevator shaft from an elevator controller controlling the movement of the elevator car, and - for determining if the elevator car is at the level of the position sensor based on the received position information. In general, by this, the position sensor receives two information. Typically, even if one of the information, e.g., the position of the elevator car by direct measurement of the position sensor, is not available, the position of the elevator car can be determined reliably. Thus, in general, it can still be determined if the elevator car is at the height/level of the position sensor. Hence, typically, the maintenance person can be warned that the elevator car is not at the height/level of the position sensor and be made aware of the danger very reliably.

According to an embodiment, the warning system is adapted for comparing the information if the elevator car is at the level of the elevator car based on the received position information with the information if the elevator car is at the level of the elevator car based on a measurement by the position sensor, and wherein the warning system is adapted such that the warning signal is generated when the two information do not match. By this, the safety of the elevator system is further increased, normally. In general, not only if the elevator car is not there where the maintenance person assumes it to be (i.e., at the height/level of the position sensor), but also if the two information about the position of the elevator car do not conform to each other a warning signal is generated. By this, typically, even if the position sensor measures the presence of the elevator car but according to the position information from the elevator controller the elevator car is not at that position/level, the maintenance person is warned that the elevator car is not at the height/level of the position sensor and made aware of the danger.

According to an embodiment, the warning system is battery powered,

wherein in particular the warning system is adapted such that the warning system generates a battery warning signal when a power of the battery is below a predetermined level. In general, one advantage hereof is that even when the elevator system is powered down for maintenance, the warning system is still powered. Thus, typically, even without external power, the safety of the elevator system is still ensured by the warning system. In general, the battery warning signal indicates that the battery is almost empty and has to be exchanged and/or recharged. This increases the reliability of the warning system, normally.

According to an embodiment, the unlock sensor comprises a piezoelectric sensor for detecting an insertion of a key in the lock of the elevator shaft door, and wherein the unlock sensor is adapted such that it asserts the unlocking of the lock of the elevator shaft door when the key is inserted into the lock of the elevator shaft door. Generally, by this, the insertion of a key, e.g., a lunar key, for unlocking the elevator shaft door is detected technically easily. Furthermore, typically, the insertion of the key can be detected passively, i.e., without power. Normally, this saves energy in the idle state of the unlock sensor, which is particularly important if the warning system is powered by a battery.

According to an embodiment, the warning system is adapted such that, when the warning signal is generated, a warning sound or message which is audible at the lock of the elevator shaft door is played by the warning system. Typically, this increases the safety of the elevator system further since the maintenance person is warned explicitly of the danger via an acoustic warning. This way, the danger can be clearly communicated to the maintenance person, normally. According to an embodiment of the method, when the warning signal is generated, the lock of the elevator shaft door and/or a key in the lock is caused to vibrate at least partially. Typically, one advantage hereof is that vibrations are felt by the maintenance person when the warning signal is generated, i.e., when the elevator car is not at the height/level of the position sensor. Normally, vibrations are a very noticeable signal, which can hardly be ignored. Furthermore, in general, in contrast to acoustic warning signals, which can be overheard due to other noise, talking etc., vibrations felt by the maintenance person cannot be superimposed by other sensory perception such that the vibrations are not noticed by the maintenance person. Therefore, normally, the maintenance person is made aware very reliably that the elevator car is not at the position sensor and of the possible dangers associated with that. Thus, typically, the safety of the elevator system is increased.

According to an embodiment of the method, the detecting if an elevator car is at the level of the position sensor, which is located in the elevator shaft, is carried out via optical means. One advantage hereof is that a technically simple position can be used, normally. By this, typically, the costs are reduced. Furthermore, in general, by this, the reliability of the method is increased.

According to an embodiment of the method, the method further comprises the following steps: receiving position information about a position of the elevator car in the elevator shaft from an elevator controller controlling the movement of the elevator car, and determining if the elevator car is at the level of the position sensor based on the received position information. Typically, by this, two information/data is/are received by the position sensor. Typically, even if one of the information, e.g., the position of the elevator car by direct measurement of the position sensor, is not available, the position of the elevator car can be determined reliably. Thus, in general, it can still be determined if the elevator car is at the height/level of the position sensor. Hence, typically, the maintenance person can be warned that the elevator car is not at the height/level of the position sensor and be made aware of the danger very reliably.

According to an embodiment of the method, the method further comprises the following steps: comparing the information if the elevator car is at the level of the elevator car based on the position information received from the elevator controller and the information if the elevator car is at the level of the elevator car based on a measurement by the position sensor, and generating the warning signal when the two information do not match. By this, the safety is further increased, normally. In general, not only if the elevator car is not there where the maintenance person assumes it to be (i.e., at the height/level of the position sensor), but also if the two information about the position of the elevator car do not conform to each other a warning signal is generated. By this, normally, even if the position sensor measures the presence of the elevator car but according to the position information from the elevator controller the elevator car is not at that position/level, the maintenance person is warned that the elevator car is not at the height/level of the position sensor and made aware of the danger. According to an embodiment of the method, when the step of generating a warning signal is carried out, a warning sound or message, which is audible at the lock of the elevator shaft door, is played by the warning system. Normally, one advantage hereof is that the safety is further increased. In general, by this, the maintenance person can be warned explicitly of the danger via an acoustic warning. This way, the danger can be clearly communicated to the maintenance person, normally.

In one embodiment, the warning signal can be voluntarily ignored, i.e., the warning system does not physically and/or electronically hinder the maintenance person of opening the elevator shaft door even though the elevator car is not at the level of the position sensor. Alternatively, the warning signal can trigger that the elevator shaft door cannot be opened.

The warning system can be installed at already existing elevator systems.

It shall be noted that possible features and advantages of embodiments of the invention are described herein partly with respect to a warning system for an elevator system, partly with respect to a method for warning a maintenance person of an elevator system. One skilled in the art will recognize that the features may be suitably transferred from one embodiment to another and features may be modified, adapted, combined and/or replaced, etc. in order to come to further embodiments of the invention.

In the following, advantageous embodiments of the invention will be described with reference to the enclosed drawing. However, neither the drawing nor the description shall be interpreted as limiting the invention.

Fig. 1 shows a schematic cross-section view of an elevator system with an embodiment of the warning system according to the present invention.

The figure is only schematic and not to scale. Same reference signs refer to same or similar features. Fig. 1 shows a schematic cross-section view of an elevator system with an embodiment of the warning system 1 according to the present invention. The elevator system comprises an elevator car 15 which hangs on at least one suspension traction means 17 and which can be moved in the elevator shaft 10 along a first direction by an elevator controller, wherein the first direction runs from top to bottom and vice versa in Fig. 1.

The elevator shaft 10 comprises several elevator shaft doors, which open the way into the elevator shaft 10 from different levels/floors. The elevator shaft door sill 25 is located at the bottom of the elevator shaft door.

The warning system 1 can be installed in the elevator system. In Fig. 1 , the warning system 1 is installed in the elevator system. The warning system 1 comprises an unlock sensor 36, a position sensor 35 and a warning signal generator 38. The warning system 1 can comprise a vibrating device. The vibrating device can comprise or can be a motor 40, e.g., a DC-motor. The warning signal generator 38 can be part of the unlock sensor 36, the position sensor 35 and/or the vibrating device.

The unlock sensor 36 detects if a lock 30 of the elevator shaft door is being unlocked. The unlock sensor 36 detects the unlocking during the unlocking process, i.e., while the key is in the lock 30 and still in the hand or in contact with the hand of the maintenance person. In particular, the unlock sensor 36 can detect the turning of the key in the lock 30 during the turning, e.g., the beginning of the turning. It is also possible that the unlock sensor 36 detects the insertion of the key into the lock 30 and evaluates/asserts this as unlocking the lock 30.

Typically, the lock 30 of the elevator shaft door is locked, i.e., the elevator shaft door can be only opened when the elevator car 15 is at the level of the respective elevator shaft door during normal operations (outside of maintenance operations). For opening the elevator shaft door when the elevator car 15 is not at the level/height of the elevator shaft door, the lock 30 of the elevator shaft door has to be unlocked.

The unlocking of the lock 30 of the elevator shaft door can be done with a

physical/mechanical key, e.g., a lunar key. Additionally, the unlocking of the lock 30 of the elevator shaft door can require the presence of a wireless transponder, e.g., a token with a RFID-device, near the lock 30/elevator shaft door. Also, other means for unlocking the lock 30 are possible.

The unlocking sensor detects if/when the lock 30 of the elevator shaft door is being unlocked, in particular in the process of being unlocked. When a physical key is inserted into the lock 30, a piezoelectric element of the unlock sensor 36 can detect the insertion and/or turning of a key. The piezoelectric element can be a passive device, i.e., no power is used by the piezoelectric element in the idle state, i.e., when no key is inserted into the lock 30 and/or turned. The insertion of the key into the lock 30 and/or the turning of the key in the lock 30 creates a voltage in the piezoelectric element. This way, the unlock sensor 36 detects that the lock 30 is being unlocked (e.g., a key is inserted into the lock 30).

Alternatively or additionally, a pressure sensor can detect the inserting of the key into the lock 30. The insertion of the key can be detected by the unlock sensor 36 as unlocking the lock 30 of the elevator shaft door.

The position sensor 35 detects if the elevator car 15, in particular a part of the elevator car 15, is at the height/level of the position sensor 35. The position sensor 35 is

installed/mounted in the elevator shaft 10. In particular, the position sensor 35 can be mounted at or near the elevator shaft door sill 25.

The position sensor 35 is mounted such that the top of the elevator car 15 is -at maximum- a human step below the elevator shaft door sill 25. I.e., the maintenance person has to do a step to go onto the top of the elevator car 15, at most. In particular, the position sensor 35 can be mounted such that the distance between the lower end of the elevator shaft door, i.e., the elevator shaft door sill 25, and the position sensor 35 is smaller than ca. 50 cm, preferably smaller than ca. 30 cm, more preferably smaller than ca. 15 cm. This way, a falling of the maintenance person into the elevator shaft

10/elevator shaft pit, which could cause (serious) injury to the maintenance person, is prevented. Thus, the maximum distance, which the maintenance person could fall, after opening the elevator shaft door, is the distance between the lower end of the elevator shaft door, i.e., the elevator shaft door sill 25, and the position of the position sensor 35, i.e., less than ca. 50 cm, preferably less than ca. 30 cm, more preferably less than ca. 15 cm. These distances are safe, since the maintenance person can make a small step to go onto the top of the elevator car 15 for maintenance. Larger distances (e.g., one meter or a few meters) between the top of the elevator car 15 and the elevator shaft door sill 25 can lead to a falling of the maintenance person into the elevator shaft 10, which could result in injuries to the maintenance person.

If the top of the elevator car 15 is above the elevator shaft door sill 25 while a part of the elevator car 15 is at the elevator shaft door sill 25, this causes no danger, since the maintenance person cannot fall into the elevator shaft 10 due to the elevator car 15 being there.

The position sensor 35 can be an optical sensor. For example, the position sensor 35 can send out a laser beam, which detects the presence or non-presence of the elevator car 15 at the position sensor 35. If no light of the laser beam is reflected and no reflected light reaches the position sensor 35, the elevator car 15 is not at the level/height of the position sensor 35. If light of the laser beam is reflected and reflected light reaches the position sensor 35, the elevator car 15 is at the level/height of the elevator car 15.

Other means for detecting if the elevator car 15 is at the height or level of the elevator car 15 are possible, e.g., acoustic waves, infrared light, non-laser light etc.

When the position sensor 35 detects the non-presence of the elevator car 15 at the height/level of the position in the elevator shaft 10 and the unlock sensor 36 detects the process of unlocking the elevator shaft door, a warning signal is generated by the warning signal generator 38. The warning signal generator 38 can be part of the position sensor 35. Alternatively, the warning signal generator 38 can be part of a control unit of the warning system 1.

The motor 40 of the warning system 1 is adapted to cause the lock 30 and/or a key inserted into the lock 30 to vibrate when the warning signal is generated, i.e., when the unlock sensor 36 detects the unlocking of the lock 30 and the position sensor 35 detects that the elevator car 15 is not level or height of the position sensor 35. The motor 40 can be an electric motor, e.g., a DC-motor. The vibration can be caused by a turning wheel with an imbalance driven by the motor 40. The motor 40 causes the lock 30 and/or key in the lock 30 to vibrate at least partially without damaging neither the lock 30 nor the key. The vibration are caused such that a human, who is in contact with/touches the key inserted into the lock 30, feels the vibration, even when the human is distracted by other tasks (e.g., talking (on the phone), reading a text etc.).

The warning system 1 can further comprise a control unit which controls the different elements of the warning system 1. The control unit can comprise or be a Raspberry Pi, an Arduino or a similar single-board computer.

The communication between the position sensor 35, the unlock sensor 36, the warning signal generator 38 and the motor 40 (and the control unit, if applicable) can be done via wire or wireless, respectively.

The warning system 1 warns the maintenance person in the following way:

When the maintenance person unlocks the lock 30 of the elevator shaft door to access the elevator shaft 10, the maintenance person normally assumes that the elevator car 15 is near the elevator shaft door sill 25, so the maintenance person can easily access the top of the elevator car 15. When the lock 30 is being unlocked, this is detected by the unlock sensor 36. Inserting and/or turning the key in the lock 30 can be asserted by the unlock sensor 36 as unlocking the lock 30. When the unlocking of the lock 30 is detect by the unlocking sensor, the position sensor 35 detects if the elevator car 15 is at the height/level of the position sensor 35 (i.e., where the maintenance person assumes that the elevator car 15 is).

If the position sensor 35 detects the non-presence of the elevator car 15 at the height or level of the position sensor 35, a warning signal is generated by the warning signal generator 38. The warning signal can activate the vibrating device and/or motor 40 which causes the lock 30 and/or the key in the lock 30 to vibrate/quiver (while the lock 30 is being unlocked by the maintenance person). This is sensed by the maintenance person, who is contact with the key in the lock 30. This causes awareness of the maintenance person that not everything is in order. In addition, an audio warning message can be played (e.g., "Warning, the elevator car 15 is not near this floor") so that the maintenance person is informed what the problem is. Also, a red light can be illuminated which is located at or near the lock 30. The lock 30 of the elevator shaft door can still be fully unlocked and opened, even if the elevator car 15 is not at the height/level of the position sensor 35.

The warning system 1, i.e., the unlock sensor 36, the position sensor 35, the warning signal generator 38 (and the motor 40, if applicable) can be battery powered. Thus, the warning system 1 is powered, even if there is a power outage or if the elevator system is shut down.

The warning system 1 can comprise a battery warning device which creates a battery warning signal, when the energy/power of the battery is below a predetermined level, e.g., below ca. 10% or ca. 5% of the original power/charge. The predetermined level can be a set charge of the battery. The battery warning signal can create a beep or another kind of audible signal. Additionally, the battery warning signal can be sent to central control unit or maintenance unit. The battery warning signal indicates that the warning system 1 is still operational but that the battery is almost empty and has to be replaced and/or recharged.

Alternatively or additionally to the battery, the warning system 1 can be connected to a power line.

The position sensor 35 can receive information about the position of the elevator car 15 from an elevator controller, which controls the upward and downward movement of the elevator car 15 in the elevator shaft 10. The elevator controller knows the exact position of the elevator car 15. The warning system 1, e.g., the control unit of the warning system 1 , can receive the position of the elevator car 15 from the elevator controller. In particular, the information if the elevator car 15 is at the height/level of the respective position sensor 35, which elevator shaft door is unlocked (i.e., the immediate next elevator shaft door above the respective position sensor 35) can be received by the warning system 1. Alternatively, this information can be calculated from the information about the position of the elevator car 15 by the warning system 1. The warning system 1 can compare this information (i.e., is the elevator car 15 present at the height/level of the position sensor 35) from the elevator controller or based on the information received by the elevator controller with the information from the position sensor 35 itself (i.e., the information if the elevator car 15 is at the level/height of the position sensor 35 measured by the position sensor 35).

If this data/information (1. based on the information from the elevator controller, 2. measured by the position sensor 35) is consistent, i.e., not contradicting, it is assumed that the information measured by the position sensor 35 is correct and valid. I.e., if the position sensor 35 detects the presence of the elevator car 15 in this case, no warning is generated by the warning signal generator 38. This means that no vibrations of the lock 30 and/or key in the lock 30 are caused at the respective elevator shaft door.

If this data/information is inconsistent and/or contradicting, (e.g., according to the information from the elevator controller the elevator car 15 is not at the height of the respective position sensor 35, but the position sensor 35 detects the elevator car 15 at the height of the position sensor 35, or vice versa) it is assumed for safety that the elevator car 15 is not at the height of the position sensor 35. Thus, a warning signal is generated in this case. The warning signal activates the vibrating device to cause a vibration of the lock 30 and/or key in the lock 30 when the lock 30 is being unlocked (which is sensed/asserted by the unlock sensor 36).

The warning system 1 can comprise several position sensors 35, several motors 40, several unlock sensors 36, which are installed at many different levels, in particular at all levels of a building, where the elevator system is. The position sensors 35 are installed at the respective elevator shaft door sill 25 or close to the respective elevator shaft door sill 25. It is possible that the lowest level of a building (but all other levels) does not have a position sensor 35, a motor 40 and an unlock sensor 36, since the danger resulting of the maintenance person falling into the elevator shaft 10 is smaller and the maintenance person regularly accesses the pit of the elevator shaft 10 while the elevator car 15 is not there.

A control unit of the warning system 1 can control the positions sensor and the unlock sensors 36. If an unlock sensor 36 detects the unlocking of an elevator shaft door, it checks if the position sensor 35 associated with that unlock sensor 36 (which is the next position sensor 35 below the elevator shaft door) detects the presence of the elevator car 15 at the height/level of the position sensor 35. If the respective position sensor 35 does not detect the presence of the elevator car 15 at the height/level of the position sensor 35, i.e., the elevator car 15 is not at/near the elevator door sill, the warning signal generator 38 generates a warning signal for the respective elevator shaft door.

The warning signal can start the motor 40 of the vibrating device of the respective elevator shaft door to cause the respective lock 30 and/or a key in the respective lock 30 to vibrate. This warns/informs the person opening the lock 30, that the elevator car 15 is not at/near the sill of the elevator shaft door, which the person tries to open.

When the maintenance person receives the warning that the elevator car 15 is not at or near the elevator shaft door sill 25, the maintenance person should reposition the elevator car 15 before trying to open or opening the elevator shaft door 20, again.

Finally, it should be noted that the term "comprising" does not exclude other elements or steps and the "a" or "an" does not exclude a plurality. Also, elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

List of reference signs

1 warning system

10 elevator shaft

15 elevator car

17 suspension traction means

20 elevator shaft door

25 elevator shaft door sill

30 lock of the elevator shaft door

35 position sensor

36 unlock sensor

38 warning signal generator

40 motor