HK1116465B - A method for performing an elevator rescue run and an elevator using the same - Google Patents

Description

Method for carrying out rescue and escape from elevator and elevator using same

Technical Field

The invention relates to a method for rescue escape of an elevator in an emergency situation, the elevator comprising an elevator car, a counterweight, ropes suspending the car and the counterweight, a drive motor, an emergency brake for stopping the car in an emergency situation, and a motor drive unit for supplying and controlling drive power to the drive motor and to the respective elevator.

Background

For safety reasons, the hoisting mechanism is caused to stop the car immediately during travel in the elevator shaft in an emergency. In effect, power to the drive motor and the emergency brake is interrupted, causing the drive motor to stop driving the car and the emergency brake to fall and stop the car at approximately the same time. Since such a stop will normally not occur at the landing but at any position within the hoistway, passengers will be trapped within the elevator car. In such an emergency situation, the passengers must be rescued from the elevator car as quickly as possible. This requires a technical specialist or professional on the elevator site and takes some time before such a professional arrives.

In most cases, the emergency situation is due to a power failure in the main power supply to the elevator. Emergency situations may also be caused by defects in the elevator itself, such as interruptions in safety chains with elevator controls, encoders, etc. Although after a power failure, the elevator starts to operate once power is again available, while other situations require the presence of a professional as described.

There are two different emergencies, namely those in which the car and counterweight are in an unbalanced condition, i.e. once the brake is raised, the car starts to move due to gravity. US-6196355B1 discloses an electric elevator rescue system for rescuing passengers from such a situation. However, there are also situations where the load is balanced, that is to say the car will remain in its position even after the brake has been lifted. Since the elevators are usually designed to be in a balanced state for most common operating conditions, such a balanced load condition is not uncommon.

US-A-5821476 discloses an onboard emergency device comprising an emergency DC power supply, A switching device for alternately supplying A DC voltage for winding A drive motor and an actuator for releasing an elevator brake. The switching means is usually a rotary switch with 6 contacts connected to the windings of the drive motor so that during rotation of the switch from one contact to the next, the windings of the elevator motor are continuously energized, thus advancing the car and the counterweight step by step.

Another method for moving an elevator in a balanced load situation is disclosed in EP0733577a2, which proposes providing a separate rescue drive to move the car in a balanced load situation.

The problem with any such configuration is that the respective methods of operation require the presence of a technical specialist or professional at the elevator site. In particular, once such a professional arrives at the elevator, it must control the rescue escape from the service panel. Typical rescue operations are different from a balanced load condition and an unbalanced load condition. At the beginning, the professional will raise the emergency brake, although monitoring the movement of the car. For this reason, the service panel is usually provided with a "brake release button". The practitioner actuates the brake release button and if the car is in an unbalanced load condition, the car will begin to move. Once the car accelerates to a certain speed, the professional will use the emergency brake to stop the car. By repeatedly opening and closing the emergency brake ("intermittent braking"), the car will move to the appropriate landing due to gravity, where passengers can leave the car. If the car is in a balanced load condition, the car will not move once the brake has been opened. In this case power to the car may be provided, for example, by the apparatus described in US-A-5821476 or US-4376471.

The respective methods for performing prior art elevator rescue escapes are very complicated and require special technical personnel to implement.

Disclosure of Invention

It is therefore an object of the present invention to provide a method for performing an elevator rescue run which is simple and reliable.

According to an embodiment of the invention, this object is solved by a method for performing an elevator rescue run, comprising the following rescue run sequence steps:

(a) operating the motor drive unit in a zero speed demand mode to maintain the car in its current position;

(b) raising the brake while maintaining the car in a zero speed demand mode;

(c) determining a preferred direction of movement of the car based on power data obtained by the motor drive unit; and

(d) and performing rescue and escape in the determined preferred movement direction.

In this way, the brake is not activated when the motor drive unit monitors its movement as soon as the elevator stops in the elevator shaft as usual in an emergency. In order to have an absolutely controlled state of the elevator car, the motor drive unit is operated in a zero speed demand mode, i.e. an operating mode in which the motor drive unit controls the drive motor in order to keep the elevator car in its position within the elevator shaft. Although in the zero speed demand mode the car is held in its position and after lifting the brake or on the basis of information obtained beforehand, the motor drive unit can determine whether the car is in a balanced load state or in an unbalanced load state and can also determine its preferred direction of movement. From this information, a rescue escape is performed in the determined preferred direction of movement. The motor drive can actively control the car to accelerate (i.e., through a predetermined speed) to a desired rescue escape speed regardless of whether the car begins to move upon itself or requires an external movement force to move.

Preferably, the method comprises supplying power to the motor drive unit from the emergency power supply. This is particularly required in the case of power failure. Since emergency power supplies generally have a limited capacity, it is particularly important to consume power economically. The majority of the power is used to actively move the elevator car if the car is not moving by itself. It should be noted that even if the car is in a so-called "balanced state", i.e. if the car does not move even if the emergency brake has been lifted, the car and the counterweight are not in a preferred balanced state, but rather friction or the like in the system makes it impossible to move in accordance with itself. Therefore, there is generally a preferred direction of movement of the car even in a "balanced load condition". Thus, movement in the direction opposite to the preferred direction of movement will consume significantly more power than is required. The present embodiment of the invention can determine such a preferred direction of movement of the elevator car from the power data obtained by the motor drive unit and/or from data obtained in normal operating operation prior to an emergency while maintaining the car in a zero speed demand mode. Thus, the power consumption, in particular from the emergency power supply, can be significantly reduced by embodiments of the invention.

Preferably, the motor drive unit controls the progress of the rescue escape. In particular, after the preferred direction of movement of the car is determined by the motor drive unit, its operating mode may be changed from a zero speed demand mode to a rescue demand mode, so that the car moves towards a suitable landing due to gravity or actively moves the car to such a landing. Preferably, the generator power generated by the drive motor and transmitted to the motor drive unit and/or the drive power supplied from the motor drive unit to the drive motor is used to calculate the actual position, direction of movement, speed and/or acceleration of the car. Based on this data, the car speed can be accelerated or reduced.

Preferably, the motor drive unit drives the emergency brake on after the zero speed demand operation has been established. Alternatively, the emergency brake may be manually operated, for example by a switch on a service panel. So that the motor driving unit drives the emergency brake to reduce the manual operation steps and facilitate automatic rescue and escape.

Preferably, the motor drive unit drives the operation of the rescue escape once the preferred direction of movement of the car is determined. Again, this driving can also be performed manually. The shorter the delay between completion of the determination of the preferred direction of motion and actuation of the rescue escape operation, the less power is consumed by the rescue escape.

Preferably, the rescue escape procedure is automatically initiated upon detection of an emergency. The automatic start of the rescue and escape program. Such an automatic initiation of the rescue escape procedure has the advantage that the passengers are rescued in a very short time. It may be preferred that the rescue escape procedure is not automatically initiated in certain emergency situations, for example in case of failure of the motor drive unit. In this case, it is preferable to perform the rescue escape only while the professional arrives at the elevator site.

Preferably, the method of performing a rescue escape comprises the further step of checking whether there is a main power supply to the elevator and automatically starting the rescue escape upon detection of a failure of the main power supply. In order to have a well defined state during the rescue escape and in order to avoid any disturbance caused by the sudden discovery of the main supply, a further step of interrupting the main power supply to the motor drive unit may be provided at least in the interval between the start of the rescue escape procedure and its completion.

Preferably, the motor driving unit supplies power from the emergency power supply device to the driving motor in the step of performing the rescue escape. Therefore, the actual drive motor moves the elevator car in a balanced load state during the rescue escape. Alternatively, the elevator comprises a rescue drive separate from the drive motor. Once the preferred direction of movement of the car is determined, the motor drive unit can drive the rescue drive. The rescue drive can also be started manually.

Embodiments of the invention also relate to an elevator comprising an elevator car, a counterweight, a rope suspending the car, the counterweight, a drive motor, an emergency brake for stopping the car in an emergency situation, and a motor drive unit for supplying and controlling drive power to the drive motor, wherein the motor drive unit is adapted to operate in a zero speed demand mode for keeping the car in a specific position, and to determine a preferred direction of movement of the car from power data obtained by the motor drive unit while keeping the car in the zero speed demand mode, and wherein the elevator further comprises means for setting the motor drive unit in the zero speed demand mode when preparing for a rescue escape in an emergency situation and subsequently starting operation of the rescue escape in the direction of the determined preferred direction of movement. The preferred direction of movement of the car can be determined from the power data obtained by the motor drive unit while maintaining the car in the zero speed demand mode and/or from the power data obtained by the motor drive unit during the last run of the car before the emergency situation occurred.

Preferably, the elevator comprises an emergency power supply.

Preferably, the elevator further comprises means for detecting an emergency and preferably further comprises means for automatically starting a rescue escape procedure upon detection of an emergency. For example, the motor drive unit may comprise detection means for detecting an interruption of the power supply to the motor drive unit. The motor drive unit may further comprise means for automatically starting a rescue escape procedure. To this end, the motor drive may comprise any type of buffer power storage, such as an accumulator or a capacitor, for storing pretension emergency data and for initiating a rescue mode during the supply of power from the emergency power supply. The detection means may be main power detection means which check the main power supply to the elevator and mainly to the elevator control means. The elevator further includes a main power interrupting device connected to the main power detecting device.

The elevator also includes a rescue drive separate from the drive motor. The elevator also includes an emergency drive switch for connecting and disconnecting power to the emergency power supply and the drive motor to move the car in a balanced emergency situation. The elevator rescue system may further include a power line connecting the emergency power supply and the motor drive unit and including an emergency drive switch.

The invention thus uses a motor drive unit that is already present in the elevator for supplying emergency power to the drive motor. The motor drive unit typically has inputs for an AC main power supply, a rectifier, a DC intermediate circuit and an inverter. Depending on the particular motor drive unit, the emergency power supply line may be connected to either the AC input or the DC intermediate circuit. The converter may be in the form of a VF converter (frequency converter) or a VVVF converter (voltage converter). By using a conventional motor drive unit for an elevator, the number of additional components of the elevator rescue system can be reduced.

The switch may be a conventional switch or may comprise any other type of switching means, i.e. may form part of the microprocessor control means. In particular, the emergency drive switch device may be integrated with the motor drive unit. It can be designed to automatically switch on to the emergency power supply in all or certain failure situations.

Preferably, the emergency power supply provides at least two different output voltages, wherein the brake is connected to the lower voltage output via the emergency brake switch and the higher voltage output is connected to the motor drive unit.

Preferably, the emergency power supply means includes an accumulator and a booster for increasing the output voltage of the battery. The emergency power supply also includes a battery load loop and a manager connected to the main power supply. The supercharger may be a conventional inverter that converts the battery voltage to a higher voltage that is supplied to the motor drive unit. In normal operation, the conventional motor drive unit receives an AC voltage of the order of 380V. However, the voltage required for driving the elevator car in a balanced load condition is much less than the voltage required for normal operation. Therefore, especially for the type of VVVF inverter, the drive motor usually requires a lower voltage for emergency operation. On the other hand, the motor drive unit loop requires a certain input voltage independent of a specific output voltage. Therefore, the higher output voltage of the emergency power supply should be at least about 250V, preferably 300V, more preferably 320V, and most preferably at least 350V. Thus, the higher voltage may be different depending on the normal voltage required by the drive motor and the drive motor unit circuit, respectively. The lower voltage needs to be sufficient to lift the brake. However, since the brake is preferably connected to the speed control device in the emergency mode, the lower voltage should preferably be high enough for the input voltage of the speed control loop. A typical voltage is about 24V. The DC battery of the emergency power supply may have a rated voltage of 12V or 24V. However, even in the case of a 24V battery, it is preferable to use a booster circuit to release the lower voltage from the emergency power supply to ensure a constant voltage output.

Alternatively, it is also possible to use an emergency power supply without a booster if the battery voltage is sufficiently high to supply the voltage for lifting the brake, the voltage for the electric control device and the voltage of the motor drive unit. With a motor drive unit that only requires 48V voltage, so that the battery has the capability of supplying 48V. Preferably voltage reducing means, such as a voltage divider, are provided in the emergency power supply means to supply a lower voltage, such as 24V and/or 12V, to supply the required voltage to the emergency brake and/or the electric control means.

Preferably, the emergency brake and the motor drive unit are connected to each other in such a way that the drive motor is only activated when the brake is actuated. This connection ensures that the brake is lifted before power is supplied to the drive motor. This can be done by mechanically or electrically connecting the respective switches separately. A particularly simple construction is to position the emergency brake switch relative to the emergency drive switch so that the emergency drive switch cannot be switched before switching of the brake switch is inhibited. One of ordinary skill in the art will be able to implement this solution. The connection of the switch is a simple mechanical solution. However, any other method of ensuring that the brake is lifted before power is supplied to the drive motor may be used.

Preferably, the brake and the motor drive unit are connected to each other in such a way that the brake is only activated when the motor drive unit is driven. Preferably, the connection is such that the brake is activated when the motor drive is in the operating mode. Once the brake is raised, the motor drive unit is energized prior to braking to ensure that the motor drive unit can control movement of the car. There are now motor drive units that closely monitor the movement of the car. Such a motor drive unit can thus monitor whether the car starts moving after the brake has been lifted, or whether the car is in a state of balanced load. Such a motor drive unit can also control the speed of the moving car and drive the brake to avoid any over-speed situation. The motor drive unit furthermore comprises a data storage medium comprising data of the elevator system before the failure occurs, i.e. data such as the current and voltage supplied to the motor in relation to the load state of the car, the position of the car on its path and the distance to the next landing. The slave memory may be an EEPROM or similar device, for example. The motor drive unit can use this data in order to make decisions on how to operate the car in an emergency situation, i.e. move the car by gravity, power the drive motor in order to move the car, the direction of movement of the car, etc. The reconnection can be effected by a mechanical or electrical connection.

The brake and the motor drive unit may also be activated at the same or substantially the same time.

Preferably, the elevator further comprises a main power switch for disconnecting the main power supply from the elevator, wherein the emergency brake and/or the emergency drive switch is connected to the main power switch in such a way that the brake and/or the drive motor is only activated when the main power supply is disconnected. Again, the connection of the switches may be implemented as described above. It is preferable for safety reasons to disconnect the main power supply before starting the rescue operation. Thus, emergency operation can be stopped in a controlled manner before the main power is connected to the elevator again. Without this feature, the main power would be interrupted if an indeterminate or undefined condition occurs in the rescue operation, and the main power would be supplied to the elevator even if the emergency power supply device supplies power to certain elevator components.

Preferably, the elevator further comprises a safety chain connected to a safety chain input of the motor drive unit, wherein the emergency power supply comprises a safety chain voltage output for supplying a safety chain voltage to the safety chain input of the motor drive unit via the emergency drive switch. The safety chain usually comprises a plurality of safety contacts arranged in series with each other, similar to the door contacts. The safety chain ensures that the elevator drive motor is only operated when all safety contacts are closed, i.e. if the elevator is in a safe state. In the event of a power failure, the power supply for the safety chain is also interrupted. Therefore, no voltage is applied to the safety chain input of the motor drive unit. In order for the motor drive unit to drive the motor in the rescue mode, a "pseudo" safety chain voltage needs to be provided to the safety chain input of the motor drive unit. Such a voltage may also be provided by the emergency power supply. The safety chain voltage is typically between a higher and a lower voltage, for example 48V DC and 110V AC, respectively. Alternatively, the emergency power supply may supply its power to the safety chain input. In this case, all safety chain contacts need to be closed in order to make the elevator car movable even in rescue mode.

Preferably, the motor drive unit further comprises a control input connected to a voltage output of the emergency power supply via an emergency drive switch, wherein the motor drive unit is designed to provide the drive motor with a power supply in an emergency rescue mode. In normal operation, the motor drive unit receives a control signal from the elevator control via its control input. But since the elevator control is normally not operated in the rescue mode, an emergency rescue mode signal needs to be generated and supplied to the control input of the motor drive unit. Preferably, the predetermined voltage corresponds to a lower voltage output of the emergency power supply. This configuration makes a separate emergency elevator control redundant.

Preferably the elevator further comprises a door zone indicating device, wherein the door zone indicating device is connected to the elevator rescue system to stop the car at a landing once the door zone indicating device has a signal that the car is positioned at the landing. Door zone indicating devices are common components in elevators and are necessary for proper operation of the elevator. Typically the door zone indicating device provides a signal to approach and align with the landing. In order to ensure that the elevator car is correctly positioned at the landing, even in the case of rescue operations, the door area indicating device can also be used in an elevator rescue system. Preferably the door zone indicating means stops the car at the next landing, wherein the elevator door can be opened manually by a person operating the rescue system or automatically by the elevator rescue system.

Preferably the elevator further comprises a speed control unit for controlling the speed of the car, wherein the speed control unit is connected to the elevator rescue system and in particular to the brake.

Drawings

Embodiments of the invention are described in more detail below with reference to the attached drawing figures, wherein:

fig. 1 is a schematic view of the components of an elevator according to a first embodiment of the present invention;

fig. 2 is a more detailed schematic view of an elevator according to a second embodiment of the invention; and

fig. 3 is a timing diagram of an embodiment of the present invention.

Detailed Description

Fig. 1 and 2 show similar embodiments of the invention. Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Fig. 1 shows the components of a hoisting machine 2, which hoisting machine 2 comprises hoisting ropes 8 driven by a drive motor 10 via a traction sheave 12. Preferably, the hoisting ropes are coated with steel belts. Connected to the shaft 14 of the drive motor 10 is a brake disc 16 of a brake 18. Also connected to the shaft 14 is an encoder 20, which encoder 20 provides encoding or speed control information to a service panel 41 via line 22 and to the motor drive unit 26 via the service panel 41. The motor drive unit 26 may be of the type described later with reference to fig. 2.

The elevator 2 further includes an elevator control device, a main power supply device, and the like, as described later with reference to fig. 2. The elevator 2 also comprises an emergency power supply 42 and an emergency brake switch 44.

The emergency power supply 42 includes a battery 48, a supercharger 50, and a battery load and check circuit 52. The emergency power supply provides three different output voltages, namely a lower voltage to the voltage output 54, a higher voltage to the output 56 and an intermediate voltage to the output 58. The voltage value may vary depending on the particular elevator. However, a typical voltage value is 24V DC in order to lift the brake and provide a typical voltage of 110V for the elevator safety chain and 350V DC for supplying the motor drive unit 26 and the drive motor 10 to an electrical control device, such as a speed control device. The latter voltage depends on the specific construction of the motor drive unit 26. Such a motor drive unit 26 typically requires a minimum input voltage even though the output voltage to the drive motor 10 will be small in the balanced load emergency operation mode.

A lower voltage is supplied to the service panel 41 via line 60 and the brake 18 can be lifted from distribution via line 61 connecting the service panel 41 and the brake 18 or via line 63 connecting the motor drive unit and the brake 18. In the latter case, the motor drive unit 26 may control the brake 18. Instead of two lines, there may be only one of the lines 61 and 63. The line 89 supplies a low voltage from the service panel 41 to the motor drive unit 26 and/or communicates information between the service panel 41 and the motor drive unit 26.

It should be understood that a single encoder 20 is used instead of two encoders in accordance with the embodiment of the invention shown in fig. 1 and 2. In particular, with the prior art, a main encoder and an additional rescue encoder are provided, and encoder information provided directly to the main encoder of the drive unit 26 is used in normal operation, while encoder information provided to the rescue encoder 20 of the service panel 21 is used only in case of rescue operation. Since the main encoder and the rescue encoder are of different types, namely a high-cost, high-resolution (about 1000-. Thus, embodiments in accordance with the present invention use only one high resolution encoder, the information of which is provided to the motor drive unit 26 via the service panel 41.

The motor drive unit 26 is of a type that is capable of determining the state of motion of the elevator car, i.e. the position, direction of motion, speed and/or acceleration of the car, from power data obtained from the motor 10 in generator mode and/or provided to the motor 10 in active drive mode. It should be noted that exemplary power data are voltage, current, frequency, etc.

This type of motor drive unit 26 may also be used as an auxiliary device to provide encoder and/or speed information in the event of a failure of the primary encoder. It is thus possible to move at least the elevator car to the next landing in the event of failure of the encoder.

The encoder 20 may be connected to a separate speed control device 24, as shown in fig. 2. But such speed control means are incorporated in the service panel 41 and/or the motor drive unit 26.

The emergency power supply 42 can be connected to the main power supply during normal operation, so that an optimum state of charge of the battery 48 can be achieved.

Fig. 2 shows an elevator 2 comprising a car 4 and a counterweight 6. The car 4 and the counterweight 6 are suspended by hoisting ropes 8. The hoisting ropes 8 are driven by a drive motor 10 via a traction sheave 12. Connected to the shaft 14 of the drive motor 10 is a brake disc 16 of a brake 18. Also connected to the shaft 14 is an encoder 20 which provides speed control information to a speed control device 22 via a line 22.

The motor drive unit 26 is connected via a line 28 with a main power supply 30 of the elevator 2 and receives control signals via a line 32 from an elevator control 34. The motor drive unit 26 supplies the required power to the drive motor 10 via a line 36 in accordance with a control signal of the elevator control 34. In particular, the motor drive unit 26 comprises a rectifier for rectifying the AC current received via the line 28, an intermediate DC circuit and a VVVF inverter (variable voltage variable frequency). The VVVF inverter varies the voltage and frequency output to the drive motor 12 via line 36 in accordance with the control signal of the elevator control device 34.

Elevator 2 also includes an elevator rescue system 40 formed from conventional components of an elevator system, namely motor drive unit 26 and speed control device 24, as well as additional components specific to elevator rescue system 40. Such additional components include an emergency power supply 42, an emergency brake switch 44, and an emergency drive switch 46.

The lower voltage from the emergency power supply 42 is supplied via line 60 and emergency brake switch 44 via the solenoid (not shown) of brake 18. A speed control switch 62 is disposed within line 60. Speed control switch 62 is controlled by speed control device 24. Which receives its information about the speed of the elevator car from the encoder 20 via line 22. Speed control 24 also receives information from Door Zone Indicator (DZI)64 via line 66. The door zone indicator 64 is connected to the door zone sensor 68 via line 70. Once the elevator car approaches and reaches landing 72, door zone sensor 68 provides a signal to speed control device 24. Thus, in case the elevator car 4 is over-speeding or in case the elevator car 4 reaches the landing 72, the speed control means may interrupt the power supply to the brake 18.

The higher voltage is supplied from the output 56 via line 74 to a power input 76 of the motor drive unit 26. The emergency drive switch 46 is located within line 74. The intermediate voltage is passed from output 58 to safety chain output 80 via line 78. In addition, the lower voltage from output 54 is connected via line 82 through a control signal input 84 of motor drive unit 26.

The emergency drive switch 46 actually includes three switches located in lines 82, 74 and 78. Thus, the emergency drive switch 46 in combination switches the lower, intermediate and higher voltages to the motor drive unit 26. However, there is no need to incorporate switching of the voltage to the motor drive unit 26. Thus, there may be three separate switches instead of the usual emergency drive switch 46.

The elevator also includes a main power switch 86 located within the main power supply line 30. It is preferred to disconnect the main power supply from the elevator 2 before starting the emergency drive mode operation in order to ensure a well defined operating state even in case the main power supply can be re-established in the emergency mode. Preferably, the main power switch 86 is mechanically or electrically connected to the emergency drive switch 46 and/or the emergency brake switch 44. In this description it should be understood that for the sake of clarity only a part of the connections between the main power supply line 30, the elevator control 34 and the individual elevator components are shown in the figures. For example, the figures do not show the safety chain that is normally connected to the elevator control 34. The main focus of fig. 1 is on the emergency rescue system and the elevator components embedded therein.

Switches 44, 46 and 86 are preferably located at convenient locations near the elevator 2, such as integral with a control panel (not shown). The switch may also be located suitably remote from the lift 2, for example in a building control room or the like.

It should be understood that similar to fig. 1, fig. 2 is a schematic and specifically shows various separate control devices, switches, etc., wherein all or some of the components may be incorporated within the motor drive unit 26. In particular, the speed control device 24, the speed control switch 62, and/or the door zone indicator 64 may be part of the motor drive unit 26. An emergency brake switch 44 may also be incorporated within the motor drive unit 26. In this case, a single manually operated switch, such as switch 46, may be sufficient to drive the motor drive unit and initiate emergency operation of the management and control by the motor drive unit, as shown in fig. 1.

The operation of the elevator 2 of fig. 2 in an emergency situation is as follows:

mode 1 (this method is not in accordance with the invention, but can be used as a backup method, for example, in the event of a failure of the motor drive unit 26):

after a failure of the elevator has been detected, the technician or any other professional switches the switch 44, thus supplying a lower voltage to the brake 18 and lifting the brake. If the elevator 2 is in a balanced state, the elevator car and the counterweights 4 and 6, respectively, will start moving. The speed control device 24 monitors the speed of the elevator car 4 and will stop the car 4 if an overspeed condition occurs. Subsequently, the sensor 68 will detect whether the elevator car 4 is in the door zone, transmit the respective signal via line 70 to the door zone indicator 64 and interrupt the power supply to the brake 18 via the speed control device 24 and the speed control device switch 64. Thus, the elevator car 4 will stop at the landing 72. The professional can then manually open the elevator hoistway doors as well as the elevator car doors. The emergency brake switch 44 may be closed if the car 4 is not moving within a fixed time period. In this case, mode 1 rescue operation may be reattempted once or twice (or even multiple times).

Mode 2:

in mode 2 rescue operation, the operator or any automatic rescue control device, such as motor drive unit 26, switches emergency drive switch 46, thereby switching lower, intermediate, and higher voltages to motor drive unit 26. The lower voltage received via the control signal input 84 provides the motor drive unit 26 with a signal for a rescue drive mode, i.e. lower power, lower speed, etc., and the motor drive unit 26 will start operating in a zero speed demand mode. Subsequently, a lower voltage is supplied to the emergency brake switch 44 via line 88 and the brake is raised. Thus, no mechanical connection of the emergency brake switch 44 and the emergency drive switch 46 is required. The intermediate voltage "forges" the positive safety chain signal at the safety chain input 80, i.e. the motor drive unit 26 gets a signal as if the safety chain (not shown) is operating properly and providing a signal that all safety chain contacts are closed. The motor drive unit 26 also receives a higher voltage via the input 76 and therefore supplies a drive voltage to the drive motor 10 via the line 36 as required in order to hold the car 4 in its position. Once the motor drive unit determines the load/motion state of the car, the motor drive unit 26 will start the rescue escape and the drive motor 10 will move slowly or cause the elevator car 4 to move in the preferred direction of motion until the sensor 68 provides a signal to the door zone indicator 64 that the elevator car 4 has reached the landing 72. If so, the speed control 24 will activate the brake 18 and stop the car 4 at the landing 72. The operator may then manually activate the emergency drive switch 46. Alternatively, there is an automatic system that resets the emergency drive switch 46. The operator can open the elevator door at the landing 72 so that the trapped person leaves the elevator car 4. The door can also be opened automatically.

The operation of the hoist 2 of fig. 1 is similar to the operation of the hoist 2 of fig. 2. The main difference is that for the embodiment of fig. 1 a so-called Brake Release Button (BRB) starts the rescue escape procedure. Similarly, the elements and functions of the embodiments of fig. 1 and 2 are relatively similar, such that the elements and functions described with respect to any figure are equally applicable to other figures unless a particular combination is clearly inconsistent with other portions of the embodiments.

As shown in fig. 1, the low voltage is provided to the service panel via line 60. This may be a continuous connection such that the service panel 41 continuously receives a low voltage from the emergency power supply 42 via line 60. Upon detection of an emergency, the car 4 stops in the hoistway, the brake release button 45 toggles and generates a brake release button signal as shown by the top line of fig. 3. Subsequently, the service panel 41 generates a high voltage, causing a signal to be sent via line 92 to the emergency power supply 42, thereby providing high and/or medium power to the motor drive unit 26 via lines 74 and 78. Thus, some or all of the emergency power switches may be integral with the emergency power supply 42. The motor drive unit 26 generates a drive idle signal at time T3 and the car data is set to "0" as shown in the last line of fig. 3. Then at time T4, the brake-on voltage is supplied to the brake 18 via line 61 and/or line 63, and the brake is on so that the car is held by the drive motor 10 controlled by the motor drive unit 26 in the zero speed mode.

The motor drive unit 26 operates in the zero speed demand mode between time T4 and time T5 during which time the motor drive unit 26 can determine the preferred direction of movement of the car 4 from power data obtained/received by the drive motor 10 during this time period and/or power data stored in the motor drive unit 26. The car speed is then slowly accelerated and then maintained at a predetermined, usually relatively low level until the door zone indicator "DZI" approaches the landing at least at time T6, whereupon the car speed gradually decreases and the brake release power is turned off so that the car 4 stops at the landing. At approximately the same time, the high voltage enable signal turns off so that the subsequent drive idle signal to the motor drive unit 26 is interrupted. Finally, the signal provided by the brake release button 45 is stopped.

Claims (16)

1. A method for elevator rescue escape in an emergency situation, the elevator (2) comprising an elevator car (4), a counterweight (6), a rope (8) suspending the car (4) and the counterweight (6), a drive motor (10), an emergency brake (18) for stopping the car in an emergency situation, and a motor drive unit (26) for supplying and controlling drive power to the drive motor (10), the method comprising the following rescue escape procedure steps:

(a) operating the motor drive unit (26) in a zero speed demand mode to maintain the car (4) in its current position;

(b) lifting the brake (18) while maintaining the car (4) in a zero speed demand mode;

(c) determining a preferred direction of movement of the car (4) from power data obtained by the motor drive unit (26); and

(d) and performing rescue and escape in the determined preferred movement direction.

2. The method of claim 1, further comprising supplying power from an emergency power supply (42) to the motor drive unit (26).

3. Method according to claim 1 or 2, characterized in that the motor drive unit (26) controls the rescue escape operation.

4. The method of claim 1, wherein after establishing the zero speed demand operation, the motor drive unit (26) activates an emergency brake (18) to open the emergency brake.

5. Method according to claim 1, characterized in that the motor drive unit (26) initiates a rescue escape operation once the preferred direction of movement of the car (4) has been determined.

6. The method of claim 1, wherein the rescue escape procedure is automatically initiated upon detection of an emergency.

7. Method according to claim 6, characterized in that it further comprises the step of checking whether there is a main power supply to the elevator (2) and automatically starting a rescue escape procedure upon detection of a main power failure.

8. The method according to claim 7, further comprising the step of interrupting the main power supply to the motor drive unit (26) at the beginning of the rescue escape procedure and at least before the rescue escape is completed.

9. Method according to claim 1, wherein the motor drive unit (26) supplies power to the drive motor (10) during the rescue escape step.

10. Method according to claim 1, the elevator (2) comprising a rescue drive separate from the drive motor (10), wherein the motor drive unit (26) activates the rescue drive as soon as the preferred direction of movement of the car (4) is determined.

11. An elevator (2) comprising an elevator car (4), a counterweight (6), a rope (8) suspending the car (4) and the counterweight (6), a drive motor (10), an emergency brake (18) for stopping the car (4) in an emergency situation, and a motor drive unit (26) for supplying and controlling drive power to the drive motor (10), wherein the motor drive unit (26) is adapted to operate in a zero speed demand mode for keeping the car (4) in a specific position, and to determine a preferred direction of movement of the car (4) from power data obtained by the motor drive unit (26) while keeping the car (4) in the zero speed demand mode, and wherein the elevator (2) further comprises means for setting the motor drive unit (26) to the zero speed demand mode in preparation for a rescue escape in an emergency situation and subsequently starting the rescue in the determined preferred direction of movement An escape operating device.

12. The lift (2) according to claim 11, further comprising an emergency power supply (42).

13. Elevator (2) according to claim 11 or 12, characterized in that it further comprises means for automatically starting a rescue escape procedure upon detection of an emergency.

14. Elevator (2) according to claim 13, characterized in that the detection means are main power detection means.

15. The elevator (2) of claim 14 further comprising a main power interrupting device (86) connected to the main power detecting device.

16. The elevator (2) according to claim 11, characterized in that it further comprises a rescue drive separate from the drive motor (10).