HK1137004B - Elevator safety device - Google Patents

Description

Elevator safety device

Technical Field

The invention relates to an elevator safety arrangement for realizing a safety space in an elevator shaft, which safety arrangement comprises a mechanical safety device which is moved into a working position in order to ensure a sufficient safety space in the elevator shaft, and a method for realizing a safety space in an elevator shaft.

Background

Problems are often encountered when elevators in old buildings need to be modernized, because the safety regulations have changed with the change of the years, and the space above and below the elevator car in the elevator shaft is not large enough to meet the requirements of the new safety regulations. Extending the shaft upwards or downwards is in most cases impossible or at least too expensive in view of construction technology and difficult to be considered as an alternative.

One idea when building new buildings is to save space in the elevator shaft. This is achieved by designing the space above and below the car in the elevator shaft to be as small as possible. In this case there is not enough safety space in the elevator shaft above and below the elevator car to provide personal protection for the serviceman working above the elevator car or in the elevator shaft.

In the case of old buildings, safety regulations require a limitation of the shaft space above and below the car, since the elevator shaft is provided with a mechanical safety device, the setting of which is associated with the work performed in the elevator shaft, in order to ensure that there is sufficient safety space in the upper and lower parts of the elevator shaft. These safety devices limit the furthest end of the path of movement of the elevator car in the elevator shaft so that the installer has sufficient working space. In the future, similar security solutions officially approved by authorities may also be used in newly built buildings.

A commonly used safety device is a turnable buffer placed at the bottom of the shaft so that the serviceman can change it into a vertical working position before starting work in the elevator shaft. The turnable buffer can be placed on the bottom of the elevator shaft below the elevator car, in which case it will limit the movement of the elevator car in the shaft bottom space, or it can be placed below the counterweight, in which case it can limit the movement of the counterweight in the shaft bottom space while limiting the movement of the elevator car in the shaft upper space. In this case, in order to determine the safety distance required in the upper space in the elevator shaft, it is necessary to take into account the problem that the elevator car will continue to move upwards in the upper end of the shaft due to its kinetic energy when the counterweight hits the buffer at the bottom of the shaft. The length of this movement depends on the maximum possible speed that the elevator car can have at the moment when the counterweight hits the buffer. The safety distance must therefore be designed such that it corresponds to the maximum possible speed at the moment of impact. In addition, the buffer compression caused by the impact must be taken into account when determining the safety distance in the headroom and the footage of the elevator shaft.

The prior art previously known is described in specification WO 97/23399. This specification discloses an arrangement for providing a safety space in the lower end of an elevator shaft. The device comprises a support pillar arranged in the path of the car frame and turned to a working position by means of an actuating element fastened to the shaft floor and the support pillar. Arranged in connection with the support pylon are the required switches for showing the position of the support pylon.

The operation of the mechanical safety device must also be checked according to the specifications. It is necessary that the system be able to detect a serviceman entering the elevator shaft and likewise the operating state of the mechanical safety device.

Specification JP03018575 discloses a switch mounted in conjunction with a mechanical safety device, the position of which changes when the mechanical safety device is turned into the operating position. Operation of the elevator motor is not permitted until a change in state of the switch indicates that the mechanical safety device has been switched to the operating position. The solution of the electronic safety device described in this specification is based on separate components, such as relays and switches, and is therefore very complex in terms of the required wiring. Moreover, the testing of the operation is very important in terms of safety of the switching operation, requiring separate control logic and thus further increasing the complexity of the solution. Because the electronic safety devices are implemented using separate components, such as relays and switches, the system is very sensitive to momentary short circuits and contact problems in the control of the switches, which can occur at any time in an elevator system. The reliability of the operation of the elevator system also decreases if the operation of the elevator system is interrupted due to a momentary open circuit such as this. For safety devices to comply with various regulations, it is additionally necessary to be able to detect persons entering the elevator shaft and to take this into account in the design of the operating logic of the safety device.

Specification EP1159218B discloses an elevator safety arrangement comprising an electronic safety controller reading data from sensors connected to the elevator system, which when it detects a safety risk in the elevator system, sends control signals to the elevator motor controller to the elevator brake and to the control center of the elevator system. However, the safety controller according to this specification cannot provide a safety level per se sufficient to correspond to the operation of the safety device according to the present invention. For the realization of a safety arrangement that is in compliance with regulations, it is necessary to provide the elevator shaft with detectors for defining the permitted limits of travel of the elevator car in the elevator shaft during maintenance operations, additional detectors defining the permitted limits of travel of the elevator car during normal operations. In addition, a plurality of detectors are required to identify the "someone in shaft" condition, such as when an installer enters the elevator shaft. In addition, there is a need for a control logic to monitor the safety of the elevator system on the basis of the detector data in the different operating modes of the elevator system.

Disclosure of Invention

The object of the invention is to disclose a new safety device for realizing a safety space in an elevator shaft as required by the respective specifications. Another object of the invention is to disclose a new type of electronic safety system that can monitor whether a person enters the elevator shaft and the status of the mechanical safety device.

Features of the invention

Embodiments of the invention are also presented in the description part of the present application. The inventive content disclosed in the application can also be defined in other ways than is done in the claims below. The inventive content may also consist of several separate inventions, especially if explicit or implicit sub-tasks are considered or relative to advantages or sets of advantages achieved. In such cases, some of the attributes contained in the claims below may be superfluous from the point of view of separate inventive aspects.

The invention relates to an elevator safety device and a method according to the installation device.

An elevator safety arrangement for achieving a defined safety space in an elevator shaft, said safety arrangement comprising a mechanical safety device, preferably a column or a barrier, which can be moved into a working position in order to ensure a sufficient safety space in the elevator shaft. Furthermore, the security device further comprises an electronic security system comprising: at least one detector in conjunction with the mechanical safety device for identifying the operating state of the mechanical safety device, and at least one detector in conjunction with an elevator landing door, means for identifying the position of the landing door, and for reading the detector fitted in conjunction with the landing door, at least one detector in conjunction with an elevator car door, means for identifying the position of the elevator car door, means for reading the detector provided in conjunction with the elevator car door, and an electronic safety controller, which reads data from an elevator control and additionally from the detector comprised in the electronic safety controller, and on the basis of the data obtained, controls one or more mechanical stopping devices, which stop the movement of the elevator car in the elevator shaft. In addition, the electric safety system comprises a data interface bus between the electric safety controller and the elevator control, in which bus data are transmitted both for determining the safety of the elevator and for controlling the elevator in normal operating situations.

The electric safety controller reads information about the position of the elevator landing door and the position of the elevator car door and, on the basis of this information, deduces whether a person has entered the elevator shaft, i.e. deduces a "person in shaft" status. After the "someone in the shaft" condition has been detected, the electric safety controller allows maintenance operations only after it detects that the mechanical safety device has assumed its operating position. For example, the maintenance personnel can access the elevator shaft by manually opening the access door by means of a key for this purpose.

In a preferred embodiment of the invention the safety arrangement further comprises at least one detector in conjunction with the elevator maintenance operation unit for identifying the status of the control of the elevator maintenance operation unit and at least one end limit marker in the vicinity of each end of the elevator shaft, at least one end limit marker reader in conjunction with the elevator car for determining the extreme limits of movement of the elevator car in the elevator shaft.

The above-described elevator control apparatus includes, for example, an elevator system controller, an elevator motor controller, and an elevator car door controller.

In one embodiment of the invention two separate sets of end limit markers are placed in the elevator shaft near each end for determining the position of the elevator car, of which end limit markers the end limit markers located closer to the ends of the elevator shaft determine the extreme limits of movement of the elevator car during normal operation and the end limit markers located further from the ends of the elevator shaft determine the extreme limits of movement of the elevator car during maintenance operation. A reader for reading end limit markers is fitted in conjunction with the elevator car, the reader being connected to the electric safety controller via a data interface bus.

In a preferred embodiment of the invention the arrangement comprises two end limit readers fitted in conjunction with the elevator car and two end limit markers fitted at either end of the elevator shaft. The reader used in this embodiment for reading the end limit markers is a switch and the end limit markers used are ramps which are fitted in the elevator shaft in such a way that the switch mounted in conjunction with the elevator car comes into contact with the ramp and opens when the elevator car moves in the shaft until it reaches the ramp. The position of the ramp in the shaft and the position of the switches in conjunction with the elevator car have been chosen so that they overlap each other so that one of the switches, called K1, can be in contact with the ramp located further away from the end at the upper end of the elevator shaft and with the ramp closer to the end at the lower end of the elevator shaft. Correspondingly, the switch K2 may be in contact with a ramp closer to the end at the upper end of the elevator shaft and with a ramp further from said end at the lower end of the elevator shaft. Using the electric safety controller, the state of the switch is read, from which state the position of the elevator car in the elevator shaft is inferred. If it is detected that the switch K1 and the switch K2 are open, the elevator is prevented from normal and maintenance operation. If it is detected that only the switch K1 is open, only maintenance operations in the upward direction are inhibited. If it is detected that only the switch K2 is open, only the maintenance operation in the downward direction is suppressed. The advantages that this approach brings include that all four end limit markers can be read by two simple end limit marker readers, such as switches. This reduces the amount of wiring between the reader and the electric safety controller.

The detector fitted in conjunction with the elevator landing door may preferably be a switch, the contacts of which are opened by an imposed control as the landing door opens. The switches are arranged in series in a series circuit, connected to the electric safety controller via a gateway so as to allow a measurement of the state of the series circuit.

In one embodiment of the invention the means for reading the detector fitted in connection with the elevator landing door comprise a resistor of the same resistance value fitted in parallel with each switch in the series circuit. In another embodiment of the invention the means for reading the detectors fitted in connection with the elevator landing doors comprise resistors with different resistance values fitted in parallel with each switch in a series circuit to identify the position of each individual switch. When resistors having different resistance values are used, the position of each individual switch in the series circuit can be identified. The resistor according to the invention may preferably be an encapsulated thin film resistor. Such a thin film resistor may be, for example, a metal film resistor. The structure of the thin film resistor allows the resistive element to be well protected from, for example, impurities. This means that the resistor is less likely to experience a fault that shorts out the resistive element. This improves the reliability of the measurement circuit using the thin film resistor. The electric safety controller may additionally comprise means for measuring the total resistance of the series circuit. Such a device may comprise, for example, a voltage source, arranged in connection with the electric safety controller and for supplying a voltage to the series circuit, and a current measuring sensor for measuring a current flowing in the series circuit. From the ratio between the supplied voltage and the measured current, the total resistance of the series circuit can be inferred. This circuit brings the advantage that the number of switches open in the series circuit can be obtained by measuring the total resistance if all resistors in the series circuit have the same resistance value. If the switch is set in connection with a door, such as reaching the door, the number of times the door is opened may be detected.

The state of the switches in the series circuit can also be determined using the same apparatus and method without a resistor in parallel with the switches. In this case, the opening of one of the switches causes an interruption of the current flowing through the switch.

The electric safety controller according to the invention can be integrated in connection with another device used in the control of the elevator system. The safety arrangement of the invention can also be used in elevator systems without machine room, in which case the space saving achieved by integrating the electric safety controller is an advantage. Furthermore, the safety arrangement of the invention can also be used in elevator systems without counterweight.

In one embodiment of the invention, information is transmitted from a control device fitted in conjunction with the elevator car to the electric safety controller via a digital interface bus. The information transmitted comprises at least data of the control of the elevator maintenance operation unit, data about the position of the elevator car in the elevator shaft, data about the state of the end limit switches of the elevator shaft during normal operation and maintenance operation, respectively, data about the position of the manhole cover in the upper part of the elevator car, and data about the state of the doors of the elevator car. According to the electric safety controller, data at least about the operating state of the electric safety controller are transmitted via a data interface bus to a control device fitted in conjunction with the elevator car.

Via the interface bus, data is also transmitted between the electric safety controller and the elevator motor controller, and data is also transmitted between the electric safety controller and the elevator system controller. The elevator motor controller sends at least a request to close the main contactor and a request to release the brake to the electric safety controller. In addition, the elevator motor controller sends a request to the electric safety controller to open the door in advance as the elevator car approaches the target floor. The electric safety controller also sends a request for closing the main contactor and releasing the brake to the electric safety controller. For the brake to be released and the main contactor to be closed, it is necessary for the electric safety controller to receive consistent control requests from the elevator motor controller and the elevator system controller. The electric safety controller sends data at least about its operating state to the elevator system controller and the elevator motor controller.

In a method according to the invention for realizing a safety space in an elevator shaft, the number of landing door openings is read by means of a detector fitted in conjunction with the landing door, the number of elevator car door openings is read by means of a detector fitted in conjunction with the elevator car door, and the position of a mechanical safety device is read by means of a detector fitted in conjunction with said mechanical safety device. These reading operations may be performed by an electronic safety controller comprising means for measuring the total resistance of the series circuit. The number of gate openings can be read from the total resistance of the series circuit. If it is detected according to the method that the number of landing door openings is greater than the number of elevator car door openings, the safety system is set to the "someone in the shaft" state and elevator operation is prevented. If it is determined during the "someone in the shaft" state of the safety system that the number of landing door openings equals the number of elevator car door openings and that the mechanical safety device has been set to the maintenance position, maintenance operations are allowed. In an embodiment according to the invention a manually controlled reset mechanism is arranged in conjunction with the electric safety controller to allow the elevator system to be restored to normal operation. In one embodiment of the invention the aforesaid reset mechanism is disposed on the lowermost floor of the elevator shaft. In another embodiment of the invention the reset mechanism is integrated with the operation interface for maintenance operations of the elevator system.

In the method according to the invention, after the security system has set entry into the "person in shaft" state, data about this change is saved in the non-volatile memory of the electronic security controller. According to a preferred embodiment of the invention, the state of the manually controlled reset mechanism is also read by means of the electric safety controller, and when it is detected that the reset mechanism has been reset to a state in which the suppression of normal operation is cancelled, the program executed by the electric safety controller is reset from the state "someone in the shaft", and data about this change is stored in the non-volatile memory of the electric safety controller. Data relating to the change to the "person in shaft" state and the cancellation of this state may also be sent to the control device via the data interface bus.

In one embodiment of the invention, the data of the detectors in the electronic safety system are read simultaneously by at least two microcontrollers via the connection interface of the electronic safety controller, the data items read by the microcontrollers of the electronic safety controller are compared with one another and the operating state of the microcontrollers is monitored via a communication bus between the microcontrollers. If the data read from the detectors are found to be different between the microcontrollers or a fault situation is found in the operating state of the microcontrollers, the operation of the elevator is prevented by actuating at least one mechanical stopping device by means of the electric safety controller, in the same connection the command to prevent operation is transmitted by the electric safety controller via the data interface bus to the controller of the elevator motor, and data about the prevention of operation is transmitted to the control device.

In one embodiment of the invention, the electric safety controller comprises a non-volatile memory for storing data during a power failure. The non-volatile memory is arranged to communicate with at least one processor of the electric safety controller via a communication bus reserved for this purpose.

In the method according to the invention, an electronic security controller is used which contains a non-volatile memory. In this method, the operating voltage of the electric safety controller is read by means of the electric safety controller itself. The program executed by the electric safety controller is set to a state in which data is written into the non-volatile memory of the electric safety controller if it is detected that the operating voltage of the electric safety controller has dropped below a certain limit value. Those variables of the electric safety controller which describe the current state of the program executed by the electric safety controller at the moment of activation of the writing process are written into the non-volatile memory of the electric safety controller.

In another method according to the invention, the electric safety controller is similarly used, which comprises a non-volatile memory, to which those variables of the program being executed by the electric safety controller which describe the state instantaneously present in the program being executed by the electric safety controller are written at regular time intervals, for example at intervals of 10 milliseconds. In addition, in this method, in connection with each writing situation, an index variable for the subsequent identification of the writing situation is stored in a non-volatile memory of the electric safety controller. When the program of the electric safety controller is restarted, for example after a power failure, those variables which describe the state of the program executed by the electric safety controller are read from the non-volatile memory of the electric safety controller, the index variables having been used to mark the latest state of the program of the electric safety controller. This method has the advantage that, in addition to allowing the operating state of the electric safety controller before the interruption of the operation established from the maximum value of the index variable, the preceding operating states can also be established in the order of the indices. This brings advantages, for example, when the operation of the safety device will be explained later. In the method according to the invention, the switches defining the state of the landing doors are arranged in series in a series circuit, and resistors having the same resistance value are fitted in parallel with the switches. In the method, a voltage is fed into the series circuit by the electric safety controller through a series resistor connected to the voltage output of the electric safety controller, and the current flowing in the series circuit is measured. According to the method, a limit value R1, R2, Rn is determined in correspondence with the current flowing in the series circuit, such that R1 corresponds to the maximum current value and Rn to the lowest current value, the limit value being defined in correspondence with the number of times the switch is opened.

In the method according to the invention, the measured current is compared to a predetermined limit value R1, R2.. Rn for the current, wherein the limit value R1 is maximum. If the measured current exceeds a predetermined limit value R1, it is concluded that all landing door switches fitted in the series circuit are closed. If the measured current is within the range of the predetermined current limit values R2.., Rn, the number of switch openings is deduced such that the lowest limit value Rn corresponds to the maximum number of switch openings, which decreases as the current value increases. In the method of the invention, the position of the switch defining the state of the access door can also be monitored without a resistor in parallel with the switch. In this case, the current flowing through the series resistor connected to the voltage output of the electric safety controller has been measured. When one of the landing door switches is open, the flow of current through the series resistor is interrupted.

In one embodiment of the invention, the voltage output of the electric safety controller does not have to be provided with a separate series resistor. In this case, the current of the voltage output is limited by some other method, for example by an active power limiting connection formed using transistors.

In another method according to the invention, said resistors having different resistance values from each other are fitted in parallel with switches defining the state of said landing doors. In the method, a voltage is fed into the series circuit by the electric safety controller through a series resistor connected to the voltage output of the electric safety controller, and the current flowing in the series circuit is measured. The measured current is compared with a predetermined current limit value R1, which relates to the maximum predetermined current limit value. At the same time, this limit value R1 corresponds to the case where all switches in the series circuit are closed. In addition, the measured current is compared with predetermined ranges of current variation, each of which represents the opening of one or more series circuit switches corresponding to the range of variation concerned. By predefining a range of current variation in which the current flowing through the series circuit must be maintained given that the landing door switch is open, it can be ensured that the current value is identifiable even if the resistance value of the resistor fitted in parallel with the switch should vary within a tolerance range or variation range.

By observing the current flowing in the series circuit, the operating state of the series circuit can also be analyzed, for example in the case of a ground fault in the series circuit. This can be achieved by measuring the current flowing into the series circuit and the current returning from the series circuit. After that, the current flowing into the series circuit and the current returning from the series circuit are compared with each other. If the value of the current flowing in it and the value of the current returning differ from each other by more than a predetermined limit value, the operation of the elevator is prevented by sending a control command to at least one mechanical stopping device by means of the electric safety controller, in the same connection a stop command is transmitted by the electric safety controller via the data interface bus to the controller of the elevator motor, and data about the prevention of operation are sent to the control device.

Although the above description provides an apparatus and a method for reading the state of a landing door switch by means of a resistor fitted in parallel with the switch, it is clear to the person skilled in the art that the operating state of other switches in the elevator system can also be read by using a corresponding apparatus and method. For example, similar apparatus and methods may be used to read end limit switches or switches that measure elevator car door position.

The mechanical stopping device according to the invention can be e.g. a braking device engaging the elevator traction sheave or a braking device engaging the elevator car guide rails. The safety device of the present invention may also include the aforementioned two braking devices.

In a preferred embodiment of the invention the electric safety controller comprised in the electric safety system comprises a connection interface and two or more microcontrollers, which are arranged to communicate with each other via a connection bus reserved for this purpose, all executing the same program independently of each other, which microcontrollers are arranged to monitor each other's operating status and to read the detector data via the connection interface and, when necessary, to send control commands to one or more mechanical stopping devices preventing movement of the elevator in the elevator shaft. The purpose of this arrangement is to ensure that when a fault occurs, the electric safety controller will still be able to secure the elevator system.

The safety device according to the invention comprises a controllable operator by means of which the mechanical safety device can be set to the operating position, said operator being controlled by an electronic safety controller comprised in the electronic safety system. The safety device also comprises means for checking the service status of the mechanical safety device by operating the controllable operator and means for checking the service status of the controllable operator. The electric safety controller has been arranged to set the mechanical safety device automatically to an operative state by means of a suitable operator control when it detects control conditions allowing manual opening of the access door and maintenance operation of the elevator maintenance operation unit.

In a preferred embodiment of the invention, at least one detector comprised in the electronic security system is double.

In another preferred embodiment of the invention, the structure of at least one detector comprises a mechanical switch that can be opened by an imposed control.

In the safety device according to the invention, the detector fitted in conjunction with the access door is a bistable switch which opens and remains open when the access door opens. In connection with the switch, means for subsequent closing of the switch may also be arranged.

In the electronic safety system of the invention, a separate detector for identifying an open access door may be arranged in connection with the elevator access door on the lowermost floor. In addition, means for reading the state of the aforementioned detectors via the communication bus, respectively, may be arranged in conjunction with the electric safety controller.

The device according to the invention comprises means for monitoring the status of a detector comprised in the electronic safety system. Arranged in conjunction with the electric safety controller are, for example, means for changing the operating state of the detector and means for measuring changes in the operating state of the detector.

Advantages of the invention

The elevator installation according to the invention has significant advantages over the prior art. The present invention can recognize the state of "someone in a shaft" via a simple device. The invention requires only the addition of a single resistor in parallel with each landing gate contact.

In the security arrangement of the invention, since the state of the detectors in the electronic security system is monitored by a separate electronic security controller, the signals to be monitored are filtered as required by the software in the electronic security controller. Thus, the system is not affected by short-term disconnection of the switch contacts. Because the number of faults of the elevator system caused by these short-term disconnections is reduced, the reliability and the utilization of the elevator system are improved.

The safety device of the present invention requires very complex operating logic to ensure that the system will recognize all possible fault conditions. The logic employed needs to exclude all operating states in which maintenance operations are prohibited and include those in which maintenance operations are allowed, based on the measurements obtained from the detector. Furthermore, the system needs to be able to infer whether the detector has been damaged. In the safety system of the invention, the monitoring of the operations is performed in a centralized manner in the electric safety controller, which simplifies the manner of implementation compared to solutions implemented using separate components. At the same time, the total number of components in the system is reduced and the reliability of the system is improved.

The electronic safety system of the present invention includes separate end restriction marks for normal and maintenance operations. In the solution of the invention, the fact that both the selection of which end limit switch to use in each case and the inference about the operating state of the safety device are carried out in a centralized manner by the electronic safety controller ensures that the operating state of the safety device determined by the measurements of the detector of the electronic safety system corresponds to the end limit marker being used. When the end limit markers are read by the electric safety controller by means of the end limit marker reader, it can be ensured that the correct end limit markers are selected in the case of a maintenance person operating the elevator in maintenance mode from the elevator shaft. By advantageously assembling the end limit markers and the marker readers in an interleaved manner, it is sufficient to use only two end limit marker readers. This simplifies the safety arrangement, reduces wiring and improves the reliability of the system. Using an electronic safety controller, direction-dependent read logic is also permitted when reading the end limit markers. If for example

Since the switches included in the elevator safety arrangement are read in the manner proposed by the invention by measuring the current flowing through a resistor fitted in connection with the switch, the status of the series-connected switches can be determined by the electric safety controller via a single current measurement. This simplifies the connection interaction between the electric safety controller and the switch to be read. In safety regulations for the elevator industry, when metal thin film resistors are preferably used as components in electronic safety circuits, short circuits of the resistors can be ignored when considering faults. When the resistor is subject to a fault of opening, this fault can always be detected by the electronic safety controller, so the resistor can also be used to measure the safety circuit, such as in the case of an arrival door switch. The resistor is also advantageously used as a component for use in measurements in electronic safety systems.

According to the invention, the "person in shaft" status is stored in the non-volatile memory of the electric safety controller, and the data concerning the transition into that status is retained until cleared by means of a specific manually operated reset mechanism. In combination with an electronic safety controller, the reset mechanism may be a switch, e.g. lockable with a key, the state of which is directly readable by the same safety controller, thus allowing a simple and advantageous solution to be achieved compared to the case of switch reading logic implemented using separate components.

In the safety controller of the present invention, the detectors in the safety device can be read in a centralized manner. Between which serial communication buses are arranged, or they may be connected in series. The amount of wiring required in the electronic security system is thus reduced.

In the electronic safety system of the invention, the operation of the different detectors can also be monitored by means of the electronic safety controller, and possible faults can be detected. Furthermore, the fault situation of the individual detectors can be distinguished and the corresponding information can be sent directly to the maintenance center, thus improving the diagnosis of the system.

As the number of separate components in an electronic safety system, such as relays, decreases, this may also reduce problems due to mechanical wear that are inherent in these components and that may limit their useful life.

Drawings

The invention will be explained in detail hereinafter with reference to the drawings, in which

Figure 1 shows a safety device according to the invention,

figure 2 shows a set of devices used in an embodiment of the invention for identifying the state of a switch,

fig. 3 shows the elevator car according to fig. 1 from above.

Detailed Description

Fig. 1 shows an elevator system employing a mounting arrangement according to the invention. The elevator car 28 has been fitted to travel in the elevator shaft 27 from the floor 21 to the floor 22. This elevator system according to the invention also comprises a counterweight 28, but the elevator system of the invention can also be implemented without a counterweight. The elevator motor 25 is disposed in the elevator shaft but may also be disposed in the machine room.

The limits of movement of the elevator car in the elevator shaft are determined by end limit markers 12, 13, 14 and 15. During normal operation the elevator car travels between the final limits determined by the end limit markers 12, 14. When the mechanical safety device 10, 18, 24 has been set into its active position, the elevator can be operated in maintenance mode only in the shaft part defined by the end limit markers 13, 15. Fitted in conjunction with the elevator car are end limit marker readers 43, 44. In this embodiment of the invention, the end limit markers used are ramps and the end limit marker reader is a switch contactable with the ramps.

Via the network management 19 the electronic safety controller reads the switches 7, 8 measuring the position of the landing doors and via the data interface bus 6 the detector 29 measures the position of the elevator car. From these positions, the electric safety controller concludes that the safety system has transitioned into a "person in shaft" state. In this case the operation of the elevator is suppressed both in normal mode and in maintenance mode.

When the switch 9 reading the operating state of the mechanical safety device indicates that the mechanical safety device has been reset to the working position, maintenance operations are allowed. The electric safety controller reads the switches indicating the status of the elevator maintenance operation via the data interface bus 6 and allows the maintenance operation by controlling the brake 26.

The elevator shaft is provided with two different sets of end limits to determine extreme limits of movement of the elevator car. During normal operation, the elevator is allowed to come closer to the end determined by the ramps 12, 14. In the maintenance operation mode, extreme limits of movement are defined by the ramps 13, 15. The electric safety controller 3 reads the position of the elevator car in the elevator shaft by means of the switches 43, 44 and stops the elevator by controlling the brake 26 when the elevator moves over a slope. When the ramp is contacted, the switch opens. In this preferred embodiment of the invention, the switches are mounted staggered with respect to the ramps, so that switch 43 reads ramps 12 and 15 and switch 44 reads ramps 13 and 14. This is achieved by arranging the ramps 12 and 15 in the elevator shaft so that they are positioned in the path of movement of the switch 43 and by arranging the markers 13 and 14 so that they are positioned in the path of movement of the switch 44 as the elevator car moves in the elevator shaft.

If it is detected that both switch 43 and switch 44 are open, the electric safety controller prevents elevator operation in normal and maintenance modes. If only the switch 43 is on, upward movement is inhibited in the maintenance operation mode. If only switch 44 is open, downward movement is inhibited in the maintenance mode of operation.

The electric safety controller 3 additionally communicates with at least the elevator system controller 2, the elevator motor controller 1 and the elevator car door controller 4 via a data interface bus 6. The electric safety controller 3 deduces the operating state of the safety gear of the elevator. If the controller detects a functional deviation from the data it has read from the detector, the controller sends a control command to the mechanical stop means 26. In addition, it sends a command to prevent operation to the elevator motor controller 1 via the data interface bus 6 and data of functional deviations to the other control devices 2, 4.

When the electric safety controller 3 detects the "someone in shaft" state, it stores the corresponding data to the non-volatile memory of the safety controller. The electric safety controller can then be restored to its normal state only by means of the manually operated reset mechanism 41. In the safety arrangement according to fig. 1, a manually operated reset mechanism is disposed on the lowest floor in the elevator shaft, and the electric safety controller reads the state of the reset mechanism via the data interface bus 6. The manually operated reset mechanism 41 may also be arranged in connection with the electric safety controller, and the electric safety controller may read the status of the reset mechanism 42 via a dedicated separate communication bus.

In the safety arrangement according to fig. 1, the mechanical safety device 24 is also arranged in the upper part of the elevator car 28. In this case, the status of the safety device can be read by the electric safety controller 3 via the data communication bus 6.

Fig. 2 shows a set of devices according to the invention that can be used to read the operating state of switches 37, 38, 39, 40 in an electronic security system. These switches are connected in a series circuit, with resistors 33, 34, 35, 36 being fitted in parallel with them. The series circuit is connected to the electric safety controller 3. The electric safety controller supplies a voltage 30 to the series circuit through a series resistor 32. The device additionally comprises means 31, 42 for measuring the current flowing in the series circuit.

The electric safety controller supplies a known voltage 30 to the series circuit through a series resistor 32. When the switches 37, 38, 39, 40 are closed, the current flowing in the series circuit is limited only by the resistor 32. The current can now be measured by the measuring means 31, 42, and the state of the series circuit can be read correspondingly. When one of the switches is open, the current path through that switch is interrupted and current begins to flow through the resistor fitted in parallel with the switch. For example, when switch 37 is open, current begins to flow through resistor 33. At the same time, the current flowing through the series circuit is reduced because the flow of current is limited by the series connection of the resistors 32 and 33. If the switch 38 is additionally opened, the current is further reduced, since the flow is limited by the series connection of the resistors 32, 33 and 34. When the current flowing through the series circuit is measured by the measuring means 31, 42, a change in the current can be detected, while a change in the state of the switch in the series circuit corresponding to the change in the current is detected.

Since the resistors in parallel with each switch 37, 38, 39, 40 have the same resistance value, the current measurement may indicate the opening of one or more of the switches. The smaller the current flowing through the series circuit, the more the switch is opened. However, in this case, it is impossible to identify which specific switch is open. If the resistors 33, 34, 35, 36 in the series circuit are chosen such that their resistance values differ from each other, the state of each individual switch in the series circuit can be identified. In this case, when selecting the resistors, it is also necessary to take into account the combination of the different resistors, so that the value of each individual resistor is different from the combination of the series connection of two or more different resistors, thereby allowing the state of the individual switch to be detected.

Using a set of devices as shown in fig. 2, a fault of the series circuit of switches, e.g. a ground fault, can also be identified. In this case, the current flowing into the series circuit is measured by the measuring device 31, and the current returning from the series circuit to the electric safety controller is measured by the measuring device 42. In the case of a ground fault, some of the current flowing in the series circuit escapes to other structural components at the point of the ground fault, only a portion of which returns to the electric safety controller 3 via the series circuit. The return current is measured by the measuring device 42 and the fault condition can be detected by comparing the current flowing out of the series circuit with the current flowing into the series circuit.

Fig. 3 is a top view of the elevator car 28 according to fig. 1. As shown, the switches 43 and 44 are disposed in a staggered arrangement with the ramps 12, 13, 14, 15 such that as the elevator car 28 moves in the elevator shaft, the ramps 12 and 15 are in the path of the switch 43 and the ramps 13 and 14 are in the path of the switch 44. Thus, the switch 43 can be used to read the ramp 15 in the upper part of the elevator shaft, which is used to determine the extreme limit of movement during maintenance operations, and the ramp 12 in the lower part of the elevator shaft, which is used to determine the extreme limit of movement during normal operations. The switch 44 can similarly be used to read the ramp 14 in the upper part of the elevator shaft, which is used to determine the extreme limits of movement during normal operation, and the ramp 13 in the lower part of the elevator shaft, which is used to determine the extreme limits of movement during maintenance operation.

The invention has been described above with reference to some embodiments. It is obvious to the person skilled in the art that the invention is not limited to the embodiments described above in a distance-wise manner, but that many variations and different other embodiments of the invention are possible within the scope of the inventive concept defined in the claims presented below.

Claims (18)

1. An elevator safety arrangement for implementing a safety space in an elevator shaft (27), the safety arrangement comprising a mechanical safety device which is moved to an operating position in order to ensure a sufficient safety space in the elevator shaft, the safety arrangement further comprising an electronic safety system comprising at least the following:

-at least one detector (9) associated with said mechanical safety device (10, 18, 24) for identifying the operating state of said mechanical safety device, and

-at least one detector (7, 8, 37, 38, 39, 40) connected to the elevator landing door for identifying the position of said landing door, and

-means for reading a detector fitted in conjunction with said access door,

-at least one detector (29) associated with an elevator car door for identifying the position of said elevator car door, and

-means for reading a detector provided in conjunction with the elevator car door,

-an electric safety controller (3) which reads data from the elevator control and additionally from detectors comprised in the electric safety controller and, on the basis of the data obtained, controls one or more mechanical stopping devices (26) which prevent movement of the elevator car (28) in the elevator shaft (27),

-a data interface bus (6) between the electric safety controller (3) and the elevator control means,

characterized in that the safety arrangement comprises two separate sets of end limit markers (12, 13, 14, 15) for determining the position of the elevator car, of which end limit markers (12, 14) located closer to the end of the elevator shaft determine the extreme limits of elevator car movement during normal operation, and end limit markers (13, 15) located further away from the end of the elevator shaft determine the extreme limits of elevator car movement (16, 17) during maintenance operation, a reader (43, 44) of the end limit markers being fitted in conjunction with the elevator car, which reader is connected to the electric safety controller (3) via a data interface bus (6).

2. The security device of claim 1, further comprising at least the following:

-at least one detector in conjunction with an elevator maintenance operation unit (5) for identifying the status of the control of the elevator maintenance operation unit, and

-at least one end limit marker (12, 13, 14, 15) near each end of the elevator shaft, at least one end limit marker reader (43, 44) in conjunction with the elevator car for determining an extreme limit of movement of the elevator car in the elevator shaft.

3. Safety arrangement according to claim 1 or 2, characterized in that one of the elevator control devices is an elevator system controller (2), one of the elevator control devices is an elevator motor controller (1), and one of the elevator control devices is an elevator car door controller (4).

4. Safety arrangement according to claim 1 or 2, characterized in that the detectors (7, 8, 37, 38, 39, 40) fitted in conjunction with the elevator landing doors (20) are switches whose contacts are opened by imposed control as the landing doors open, which switches are arranged in series in a series circuit, connected to the electric safety controller via a gateway (19) so as to allow measurement of the state of the series circuit.

5. Safety arrangement according to claim 4, characterized in that the means for reading the detectors fitted in conjunction with the elevator landing doors comprise resistors (33, 34, 35, 36) of the same resistance value fitted in parallel with each switch (7, 8, 37, 38, 39, 40) in the series circuit.

6. Safety arrangement according to claim 4, characterized in that the means for reading the detectors fitted in connection with the elevator landing doors comprise resistors (33, 34, 35, 36) with different resistance values fitted in parallel with each switch (7, 8, 37, 38, 39, 40) in series circuit in order to identify the position of each individual switch.

7. A security device according to claim 5 or 6, characterized in that the aforementioned resistor (33, 34, 35, 36) is an encapsulated thin film resistor.

8. A safety arrangement according to claim 4, characterized in that the electric safety controller (3) comprises means (30, 31, 32) for measuring the total resistance of the series circuit.

9. Safety arrangement according to claim 3, characterized in that the aforementioned electric safety controller (3) is integrated in conjunction with another control device of the elevator system.

10. A safety arrangement according to claim 1, wherein the mechanical safety device is a post or barrier (10, 18, 24).

11. A method for realizing a safety space in an elevator shaft, characterized in that the electric safety controller (3) comprises means (30, 31, 32) for measuring the total resistance of the series circuit, and, in the method, that

-the number of times the landing door (20) is opened is read by means of a detector (7, 8, 37, 38, 39, 40) fitted in conjunction with the landing door (20), the number of times the elevator car door is opened is read by means of a detector (29) fitted in conjunction with the elevator car door, the position of the mechanical safety device is read by means of a detector (9) fitted in conjunction with the mechanical safety device (10, 18, 24),

if it is determined that the number of landing doors open is greater than the number of elevator car doors open, the safety system is set to a "person in shaft" state and elevator operation is prevented,

-allowing maintenance operations if it is determined during the "someone in shaft" state of the safety system that the number of landing door openings equals the number of elevator car door openings and that the mechanical safety device has been set to the working position.

12. The method according to claim 11, characterized in that it comprises at least one of the following steps:

-after the security system has entered the "person in shaft" state, data representing this change is saved to the non-volatile memory of the electronic security controller (3),

-the state of a manually controlled reset mechanism (41) is read by the electric safety controller (3), and when it is detected that the reset mechanism (41) has been reset to a state in which the suppression of normal operation is cancelled, the program executed by the electric safety controller is reset from a state "person in shaft" to an operating state in which normal operation is allowed, data on this change being stored to a non-volatile memory of the electric safety controller (3),

-data representing the change to the "person in shaft" state and data representing the cancellation of the state are sent to the control device via the data interface bus (6),

-data are read simultaneously by at least two microcontrollers from detectors comprised in the safety system via a connection interface of the electronic safety controller (3),

data items read simultaneously by at least two microcontrollers from a detector comprised in the safety system via a connection interface of the electronic safety controller are compared with each other and the mutual operating states of the microcontrollers are monitored via a communication bus between the microcontrollers,

-if the data read from the detectors are found to be different between the microcontrollers or a fault situation is found in the operating state of the microcontrollers, the operation of the elevator is prevented by actuating at least one mechanical stopping device (26) by means of the electric safety controller (3), in the same connection the command to prevent operation is transmitted by the electric safety controller (3) via the data interface bus (6) to the controller (1) of the elevator motor, data regarding the prevention of operation being transmitted to the control devices (2, 4).

13. Method according to claim 11 or 12, characterized in that the electronic safety controller (3) contains a non-volatile memory and in that the method comprises the following steps:

-the operating voltage of the electric safety controller is read by means of the electric safety controller (3) itself,

-the program executed by the electric safety controller is set to a state of writing data into the non-volatile memory of the electric safety controller (3) when it is found that the operating voltage of the electric safety controller has fallen below a predetermined limit value,

-the electric safety controller has variables describing the current state of the program executed by the electric safety controller (3) at the moment of activation of the writing process, those variables of the electric safety controller being written into the non-volatile memory of the electric safety controller.

14. Method according to claim 11 or 12, characterized in that the electronic safety controller (3) contains a non-volatile memory and in that the method comprises the following steps:

-those variables of the program executed by the electric safety controller which describe the status instantaneously present in the program being executed by the electric safety controller are written to the non-volatile memory of the electric safety controller at regular time intervals;

-in connection with each writing situation, an increasing index variable for subsequent identification of a writing situation is stored into the non-volatile memory of the electric safety controller,

-reading from the non-volatile memory of the electric safety controller those variables with the greatest index value describing the state of the program executed by the electric safety controller, when the program of the electric safety controller is started.

15. Method according to claim 11 or 12, characterized in that the switches (7, 8, 37, 38, 39, 40) defining the state of the landing door (20) are arranged in series as a series circuit, resistors (33, 34, 35, 36) having the same resistance value being fitted in parallel with the switches, the method comprising the steps of:

-a voltage is fed into the series circuit by the electric safety controller through a series resistor (32) connected to a voltage output (30) of the electric safety controller,

-measuring a current flowing in the series circuit,

a limit value R1, R2, Rn being determined in correspondence with the current flowing in the series circuit such that R1 corresponds to a maximum current value, Rn to a minimum current value, the limit value being defined in correspondence with the number of times the switch is opened,

-the measured current is compared to a predetermined limit value R1, R2.., Rn for the current, wherein the limit value R1 is maximal,

-if the measured current exceeds a predetermined limit value R1, it is concluded that all landing door switches fitted in the series circuit are closed,

if the measured current is within the range of the predetermined current limit values R2.., Rn, then the number of switch openings is deduced such that the lowest limit value Rn corresponds to the maximum number of switch openings, which decreases with increasing current value.

16. Method according to claim 11 or 12, characterized in that resistors (33, 34, 35, 36) with mutually different resistance values are fitted in parallel with switches (37, 38, 39, 40) defining the state of the access door (20), the method comprising the steps of:

-a voltage is fed into the series circuit by the electric safety controller (3) through a series resistor (31) connected to a voltage output (29) of the electric safety controller,

-measuring a current flowing in the series circuit,

the measured current is compared with a predetermined current limit value R1, which relates to the maximum predetermined current limit value and at the same time this limit value R1 corresponds to the case in which all switches in the series circuit are closed,

-the measured current is compared with predetermined ranges of current variation, each of said ranges representing the opening of one or more series circuit switches corresponding to the range of variation concerned.

17. The method of claim 15, further comprising the steps of:

-measuring the current flowing in the series circuit,

-measuring the current returning from the series circuit,

-the current flowing into the series circuit and the current returning from the series circuit are compared with each other,

-if the value of the current flowing in the series circuit and the current returning differ from each other by more than a predetermined limit value, it is concluded that the series circuit has failed, the operation of the elevator is prevented by actuating at least one mechanical stopping device (26) by means of the electric safety controller (3), in the same connection a stop command is transmitted by the electric safety controller (3) via the data interface bus (6) to the controller (1) of the elevator motor, and data about the prevention of operation are transmitted to the control devices (2, 4).

18. The method of claim 16, further comprising the steps of:

-measuring the current flowing in the series circuit,

-measuring the current returning from the series circuit,

-the current flowing into the series circuit and the current returning from the series circuit are compared with each other,

-if the value of the current flowing in the series circuit and the current returning differ from each other by more than a predetermined limit value, it is concluded that the series circuit has failed, the operation of the elevator is prevented by actuating at least one mechanical stopping device (26) by means of the electric safety controller (3), in the same connection a stop command is transmitted by the electric safety controller (3) via the data interface bus (6) to the controller (1) of the elevator motor, and data about the prevention of operation are transmitted to the control devices (2, 4).