EP2352689B1 - Method of loosening a pick-up or a balancing weight for a lift from a catch position - Google Patents

Description

Technical area

The invention relates to a method according to the preamble of claim 1.

State of the art

Lifts consist essentially of a load-carrying means and a balance weight, which are interconnected via a suspension means. The suspension element is usually formed from several suspension ropes (steel cables), but there are also synthetic fiber ropes, flat belts, ribbed belts and the like. The load-handling device is (in particular for passenger lifts) usually an elevator car.

Lifts, in particular the load handling devices, must be equipped with safety gears. If a predetermined speed is exceeded when traveling downhill, the safety gear triggers and brakes the elevator. Such fall arresting devices are particularly intended for the event of a breakage of the carrier. In this case, the elevator accelerates downwards by 1 g (g is the gravitational acceleration). The safety gear must therefore apply much more force than the weight (weight is mass times acceleration due to gravity), otherwise the elevator would not decelerate. The same applies in the event that the balance weight is equipped with a safety gear.

High-speed elevators must be equipped with a safety gear that also operates when driving upwards, which responds when driving up too fast. For example, these upward-acting safety gears are activated on the third-highest floor and decelerate the elevator if the control fails and the upward drive does not slow down in time before reaching the highest floor. Safety gears in the Driving upward must slow down much less because with a deceleration greater than gravitational acceleration, passengers would be thrown by their own inertia against the ceiling of the elevator. Accordingly, the forces that must apply the safety gear when driving upward, correspondingly lower than the forces that it must apply when driving down.

The safety gears must be self-locking, as soon as they have triggered hold the lift until they are released. Many safety gears are designed so that they can be solved by the lift or its load-carrying means is moved counter to the direction of capture, because this is not a separate mechanism for releasing the safety gear necessary. That if the safety device has responded when traveling downhill or when driving upwards, the elevator is moved either with the drive device or with an auxiliary device counter to the direction of travel, whereby the safety gear triggers.

The problem is that the forces to release can be very large, so that the drive device can not muster these high forces. The forces for releasing the safety gear are particularly large when the safety gear has responded when traveling downhill, because in this case, the braking forces are correspondingly large.

To solve this problem is in the generic EP 1213247 A1 has been suggested that the load-bearing means against the safety gear has a certain amount of play. The drive unit can therefore accelerate the load receiving means initially a few centimeters when triggered safety gear, then strikes the lifting device on the safety gear and solves this, not only the force of the drive unit acts, but the much larger inertial force of the elevator. The safety gear is therefore unleashed like a hammer. In this method, it is necessary that the safety gear is constructed so that the load-carrying means can be moved slightly with safety gear in catch position. Without such safety gears, this method can not be used. This method thus requires a mechanical conversion of the elevator.

Furthermore, by the EP 1641700 B1 discloses a method for releasing a lifting device from the catch, in which a wire rope is fixed to the load receiving means and the balance weight, which is deflected down the shaft via a loaded with a tension weight loose roller. Depending on whether the safety gear has triggered when driving up or when driving down, the wire rope is pulled by means of a chain hoist in one or the other direction. In this method, the safety gear can be configured as desired, so it is not necessary that the safety gear in the fishing position allows limited mobility of the lifting device. However, in this method, the disadvantage arises that for loosening the lifting device from a catch an additional chain hoist with the appropriate drive must be attached to the wire.

JP4251083 discloses a method for releasing a safety gear arranged on a car from a catching position to a downward travel, wherein first the carrying means is fastened to the carrying wheel. Thereafter, the cabin was moved up to release the safety gear.

Presentation of the invention Technical task

The aim of the invention is to avoid these disadvantages and to propose a method of the type mentioned, which can be applied regardless of a, albeit small displaceability of the lifting device in the fishing position of the safety gear and requires no additional facilities. It should also be applicable to a catch of the counterweight.

Technical solution

This is achieved according to the invention in a method of the type mentioned by the characterizing features of claim 1.

Advantageous effects

The proposed measures ensures that after a catch of the load-carrying device from a downward movement by driving the drive in the sense of a downward movement, the balance weight is raised and this is thus brought to a higher potential energy level. After the reversal of the drive in the sense of an upward movement of the lifting device to release the safety gear, the balance weight falls down, whereby its potential energy is released and this supports the moment of the drive, whereby the time required to release the safety gear is applied.

The same applies to the catch of the counterweight when it was in downward travel (ie the load-carrying means in upward travel): By driving the drive in the sense of an upward movement of the lifting device, the load-receiving means is raised and thus brought to a higher potential energy level. After the reversal of the drive in the sense of a downward movement of the lifting device to release the safety gear fall the load-receiving means down, whereby its potential energy is released and this supports the moment of the drive, whereby the time required to release the safety gear is applied.

The following statements refer to the catching of the load-carrying device (the elevator car), because this is the more frequent case; however, they apply mutatis mutandis to catching the counterweight.

The drive can not raise the balance weight arbitrarily high, as long as the safety gear blocks the elevator. There are two possibilities: either the engine is not strong enough to lift the counterbalance weight until the lift cage support means are completely relaxed so that the engine locks; or it is sufficiently strong, then the suspension means begins to slip on the traction sheave as soon as the suspension means are relaxed to the cabin, because then they no longer rest with sufficient force on the traction sheave.

• Vorzugsweise ist die Zeit der Ansteuerung der Antriebseinheit mit vorbestimmtem Drehmoment, um - falls die Fangvorrichtung am Lastaufnahmemittel angeordnet ist - das Ausgleichsgewicht anzuheben oder - falls die Fangvorrichtung am Ausgleichsgewicht angeordnet ist - das Lastaufnahmemittel anzuheben, begrenzt, d.h. das vorbestimmte Moment wird nur eine bestimmte Zeit angewendet. Dies ist dann sinnvoll, wenn die Kraft des Motors nicht ausreicht, um die Tragmittel zur Aufzugskabine vollkommen zu entspannen. Die Zeit ist so zu wählen, dass das Ausgleichsgewicht maximal angehoben wird.

Accordingly, according to embodiments of the invention, two possibilities can be provided:

• Preferably, the time of driving the drive unit with predetermined torque to - if the safety gear is arranged on the lifting device - to raise the balance weight or - if the safety gear is arranged on the balance weight - to lift the load receiving means limited, ie the predetermined moment is only a certain time applied. This is useful if the power of the engine is not sufficient to completely relax the suspension means to the elevator car. The time should be chosen so that the balance weight is raised to the maximum.

Alternatively, it may be provided that the angle of rotation of the traction sheave while driving the drive unit to - if the safety gear is arranged on the load receiving means - to raise the balance weight or - if the safety gear is arranged on the balance weight - to raise the load-receiving means is limited. This is useful if the power of the motor is sufficient to cause the suspension on the traction sheave to slip.

Of course, it is also possible and useful to provide both measures and apply the predetermined moment until either the predetermined time is over or the traction sheave has turned correspondingly far, depending on what happens before.

It may seem at first glance that under these circumstances, the balance weight can only be minimally increased. However, this is not the case, as has been found in the context of the present invention, because obviously the elasticity of the support means is so large that the balance weight can be raised at least a few inches before either of the two situations described (blocking the engine or slipping of the Tragmittels on the traction sheave) occurs. However, the energy gained thereby has a very positive effect on the subsequent switching over of the direction of rotation of the traction sheave because the compensating weight is given a clear speed until the tensioning device is again completely tensioned, which helps to loosen the safety gear. If this does not succeed the first time, this process can also be repeated, as will be described.

When the drive unit of the elevator has a frequency converter-controlled motor, it is favorable if motor voltage and currents are determined by means of vector control and magnetic flux and torque are controlled independently. This results in particularly favorable conditions with regard to the control of the drive: namely, both the speed (ie the speed of the elevator) and the torque can be limited independently of each other, which is particularly important in the present application.

A particular advantage of the method according to the invention is that it can be carried out without mechanical conversions, ie that normally no technician has to appear on site. For this purpose, it is necessary that the controller recognizes in which direction the catch is to be solved. For this purpose, two options are provided according to embodiments of the invention, namely that the controller for determining the release direction the sign of the last set target speed, or that the control to determine the release direction uses the sign of the last recorded speed of the lifting device. The latter option is useful if the drive is constantly stored in the operation control; if this is not the case, the setpoint speed is used.

As already indicated above, the load-carrying means or the balance weight does not have to be released already during the first implementation of the method according to the invention; In this case, the procedure is repeated several times in succession. But it is necessary to know if the catch has been released or not. For this purpose, according to embodiments of the invention, two possibilities are provided, namely that a path of the lifting device or the balance weight or the rotational angle of the traction sheave during the action of the torque on the support means to - if the safety gear is arranged on the load receiving means - the balance weight down to move or - if the safety gear is arranged on the balance weight - to move the load-bearing means down, measured and compared with a setpoint s _max , and the previous process steps are repeated if this setpoint is not reached, or that the torque actually applied to - If the safety gear is arranged on the load-receiving means - to move the balance weight down or - if the safety gear is arranged on the balance weight - to move the load handler down, measured and compared with a target value, and that the previous procedural If this setpoint is exceeded, these steps are repeated.

In simple terms, either path or force is measured; "a lot of" way or "little" force means the safety gear has been released (and the elevator moves freely). If, on the other hand, only "little" distance is covered or if a "high" force is necessary, then the elevator is still in the catch (ie it is still blocked).

In this way, therefore, the method according to the invention can be carried out without technicians on site, which reduces the maintenance effort accordingly.

Brief description of the drawings

• Fig. 1 eine schematische Darstellung eines Aufzugs mit einer Fangvorrichtung;
• Fig. 2 ein Ausführungsbeispiel eines in beiden Fahrrichtungen des Lastaufnahmemittels wirksamen Festhaltemittels;
• Fig. 3 ein Ausführungsbeispiel für ein nur in Abwärts-Fahrrichtung des Lastaufnahmemittels wirksamen Festhaltemittels;
• Fig. 4 eine schematische Darstellung eines verglichen zu Fig. 1 anders angetriebenen Aufzugs;
• Fig. 5 ein Blockschaltbild einer Steuerung zur Durchführung des erfindungsgemäßen Verfahrens;

und Fig. 6 ein Diagramm eines nach dem erfindungsgemäßen Verfahren vorgesehenen Momentenverlaufs des Antriebs und der entsprechenden Wege.The invention will now be explained in more detail with reference to the drawings. It shows:

• Fig. 1 a schematic representation of an elevator with a safety gear;
• Fig. 2 an embodiment of an effective in both directions of travel of the lifting device retaining means;
• Fig. 3 an embodiment of an effective only in the downward direction of travel of the lifting device retaining means;
• Fig. 4 a schematic representation of a compared to Fig. 1 differently powered elevator;
• Fig. 5 a block diagram of a controller for carrying out the method according to the invention;

and Fig. 6 a diagram of a provided according to the method of the invention torque curve of the drive and the corresponding paths.

Best way to carry out the invention

Fig. 1 schematically shows a equipped with a safety gear elevator system. This consists essentially of a guided on guide rails 1 load-carrying means 2, a drive unit 3, a balance weight 4, a support means 5 (eg, a number of suspension cables) and a speed limiter system 6. The load-receiving means 2 comprises a car 10, depending on the design of an additional cabin frame 11 may have, upper Guide shoes 12 and two safety gears 13. Such a safety gear 13 is composed of a retaining means 14 and connected to the load receiving means 2 catching console 16 on which the retaining means 14 is attached and which additionally carries two lower guide shoes 17.

The load-receiving means 2 and the balance weight 4 hang on the guided by a drive pulley 18 of the drive unit 3 support means 5 and are moved by the drive system formed from these components along the guide rails up and down. In the event that a speed limit is exceeded, normally a speed limiter cable 20, which is moved synchronously with the load receiving means, is blocked by a speed limiter 21, which activates the retaining means 14 of the two safety gear 13 which are connected to one another via a coupling mechanism 22 via a coupling mechanism 22. In this clamping mechanisms contained thereby generate by utilizing the kinetic energy of the load receiving means 2, a clamping action between the retaining means 14 and the guide rails. 1

Fig. 2 shows a possible embodiment of a retaining means 14. With 1, the guide rail of a lifting device is designated. A base body 23 has a recess 24 into which the guide rail 1 protrudes. On the one side of the recess 24, a first brake shoe 26 supported by prestressed spring elements 25 is arranged in the base body 23. On the other side of the recess, a second brake shoe 27 is present, which is supported on an eccentric 28 mounted in the base body 23. This is rotatably connected to a Abrollscheibe 29, the periphery of which would touch the guide rail side, but at its periphery has a flat 30, which prevents this contact in the spring-centered normal position of the unwinding disc 29.

An overspeed of the speed governor cable 20 via the trip lever 15 (FIG. Fig. 1 ) actuated trigger mechanism 31 causes a rotation of the eccentric 28 with the unwinding disc 29 so far that the non-flattened part of the periphery of the unwinding disc 29 touches the guide rail 1. As a result of the relative movement between the guide rail 1 and the unwinding disc 29, the latter is rotated so far together with the eccentric 28 until a stop, not shown here, stops the rotation, whereupon the unwinding disc 29 is forced to slide on the guide rail 1. The rotation of the eccentric 28 causes the second brake shoe 27 supported thereon to move against the guide rail and the latter clamps in between the two brake shoes 26, 27, wherein the elastic support of the first brake shoe 26 determines the clamping force as a function of the eccentric stroke.

Depending on the moment of triggering existing movement direction of the load receiving means 2, the rolling disc 29 is rotated with the eccentric 28 in the positive direction of rotation 29 'or negative direction of rotation 29' '. "Positive direction of rotation" means counterclockwise, "negative direction of rotation" means clockwise. The limited by stops limit maximum rotation angle are different for the positive and the negative sense of rotation, creating different Exzenterhübe with correspondingly different clamping and braking forces that are adapted to the requirements for catching from downward or upward movement. As stated above, namely, the braking forces must be lower in the upward movement than in the downward movement, whereby the clamping forces are correspondingly lower.

In order to unlock the existing self-locking clamping between the retaining means 14 and the guide rail 1 after a trap, this retaining means 14 is opposite to the existing prior to the trapping movement direction of the lifting device 2 to move, which is usually done by moving the load receiving means 2 by means of the drive unit 3 , In this case, the eccentric 28 is rotated back by the rolling disc 29 in its spring-centered normal position, in which no clamping forces are generated. The unlocking requires a considerable Force, especially when a catch from the downward movement to be unlocked.

Fig. 3 shows a further possible embodiment of the retaining means 14. A base body 32 has a recess 34 into which the guide rail 1 protrudes. On the one side of the recess a rectangular brake plate 33 is embedded in the base body 32, and on the opposite side of the base body 32 includes a clamping ramp 35. A via the trigger 15 (FIG. Fig. 1 ) with the speed governor cable 20 ( Fig. 1 ) associated trigger mechanism 36 carries a cylindrical clamp body 37 which is disposed in the space between the clamping ramp 35 and the guide rail 1. When the safety gear is released, the blocked speed limiter cable causes the release mechanism 36 to lift the clamp body 37 and bring it into contact with the guide rail 1 and the clamping ramp 35 moving relative to it so that the clamp body 37 wedges between the guide rail 1 and the clamping ramp 35. By friction and deformation of the guide rail 1, the load-receiving means is braked.

In order to unlock the existing self-locking clamping between this retaining means 14 and the guide rail 1 after a trap, this retaining means 14 is opposite to the existing prior to the trapping movement direction of the lifting device 2 to move, which is usually done by moving the lifting device by means of the drive unit. In this case, the cylindrical clamping body 37 moves out of the wedge gap, so that no clamping forces are available. The unlocking requires a considerable effort.

Fig. 4 shows one opposite Fig. 1 slightly modified drive of the elevator. Same parts have the same reference number as in Fig. 1 and will not be explained again. Compared to Fig. 1 is Fig. 4 even more schematic, because it depends only on the changed drive. In particular, the upper ones Guide shoes 12 not shown, and also the retaining means 14 are not visible; they can be integrated into the lower guide shoes 17.

The main difference compared Fig. 1 is that here both the load-carrying means 2 (ie, the car 10) and the balance weight 4 are held in loose roles. Thus acts on the support means 5 only half as much force, or the support means 5 can transmit twice as much power to the car 10 and the balance weight 4. Another difference results that the traction sheave 18 has a wrap angle of 180 °, that is, a much larger wrap angle than the embodiment according to Fig. 1 , As a result, a higher torque can be transmitted, that is, the support means 5 are subjected to more force. Considering that the force is additionally doubled by the loose rollers, the transferable to the car 10 and the balance weight 4 forces in this embodiment are much larger than in the embodiment according to Fig. 1 , Since the maximum transferable force plays a decisive role in the inventive method to be described, the embodiment according to FIG Fig. 4 better suited for this method than the embodiment according to FIG Fig. 1 ,

As I said, the clamping forces are relatively low at a catch from the upward movement, so that the drive motor can solve the safety gear by driving in the downward direction. With a catch from the downward movement but the necessary forces are much larger, and here the normal drive often fails. According to the invention, the engine is therefore driven in a special way after a catch from downwards, as now on hand Fig. 5 and 6 is explained.

The block 41 "engine speed measurement" (see Fig. 5 ) provides the engine speed (and thus a measure of the speed of the elevator). The engine speed is compared in a differential amplifier 42 with a desired speed. The difference signal is the block If the deviation is 0, then it gives no signal, the deviation is small, then it delivers a corresponding correction signal, the deviation is very high, then it stops the elevator.

The block 44 "Motor current measurement" supplies the motor current (and thus a measure of the torque of the motor, that is a measure of the force acting on the load-receiving means or the balance weight). The torque is compared with a desired torque in a further differential amplifier 45. This differential amplifier 45 also receives the output of the block "speed control" 43 as an additional input signal. The resulting output signal is fed to the block 46 "current controller". Its output signal is processed in block 47 "modulator" to control signals for the switches of the "inverter power stage" 48, wherein the switching duration of the switch determine the current in the motor 40.

The special feature of this circuit is that a separate block 49 "torque profile generator" is provided for the target torque, which is necessary in the inventive method torque curve (the basis of Fig. 6 will be explained) can pretend.

Fig. 6 shows the course of the moment M (t) of the drive and the corresponding paths s (t) in the application of the method according to the invention as a function of the time t.

It can be seen from this diagram that the drive is first acted upon for a maximum time duration t _max1 in a direction opposite to that of the release device 13 (ie in the sense of the downward travel). (The release direction is in Fig. 6 indicated by an arrow to the left of the diagram.) In this case, the torque curve is predetermined by the torque profile generator 49 and converted into current values via the blocks 46, 47 and 48, that the motor 40 delivers exactly the predetermined torque curve. Any deviations are detected by the motor current measurement and compensated by the differential amplifier 45.

Due to this torque curve, corresponding paths that are detected by a motor encoder result. In this case, the negative counting direction corresponds to the release direction of the safety gear 13.

M _max is the predetermined torque which is predetermined by the torque profile generator 49. S _max is a safety limit for the way. In the case shown, this safety limit s _{max is} not reached because the motor 40 is already threatening to block when the time t _{max1 has} elapsed. If the suspension _{element slipped} on the traction sheave 18, then s _max would be exceeded within the time span t _max1 . The motor 40 is reversed in the opposite direction when either s _max or t _{max1 is} exceeded to avoid unsafe conditions, particularly _stalling (t _max1 ) of the motor 40 or _slippage of the suspension means on the traction sheave 18 (s _max ).

After switching, the motor 40 is again supplied with the predetermined torque M _max , for a time t _max2 . If within this time the lift is released (and s correspondingly takes large negative values, as shown in the diagram), normal can be continued until the next floor. If not, then the inventive method must be repeated.

According to the inventive method, the drive unit is thus first acted against the release direction of the safety gear 13, whereby the load receiving means 2 is applied downward, so that the support means 5 between the traction sheave 18 and the load receiving means 2 is relaxed and there is a lifting of the balance weight 4. After reversing the drive unit 3, the direction of rotation changes, and the energy stored in the balance weight 4 supports the drive unit 3 in doing so Lifting device 2 in the release direction of the safety gear 13 (ie upwards) to move and to solve them.

Claims (8)

1. Method for the release from an emergency-stopped position after downward travel of a safety device (13) that is arranged on a load-carrying means (2), or on a compensating weight (4), of an elevator, the load-carrying means (2) being connected via a suspension means (5) to the compensating weight (4) and both together, by means of a drive unit (3), which comprises a reversible electric motor (40) and a traction sheave (18), over which the suspension means (5) is passed, are movable, characterized in that the drive unit (3) initially acts with a predetermined torque (M_max) on the suspension means (5) and thereby, if the safety device (13) is arranged on the load-carrying means (2), raises the compensating weight, or, if the safety device (13) is arranged on the compensating weight (4), raises the load-carrying means (2), and thereafter acts in the opposite direction of rotation with a predetermined torque (M_max) on the suspension means (5), whereby the raised compensating weight (4) or the raised load-carrying means (2) respectively is moved downward.
2. Method according to Claim 1, characterized in that the time for application to the drive unit (3) of a control signal with predetermined torque (M_max), in order to - if the safety device (13) is arranged on the load-carrying means (2) - raise the compensating weight, or - if the safety device (13) is arranged on the compensating weight (4) - raise the load-carrying means, is limited (t_max1).
3. Method according to Claim 1 or 2, characterized in that, during the application of a control signal to the drive unit (3), an angle of rotation of the traction sheave (18) in order to - if the safety device (13) is arranged on the load-carrying means (2) - raise the compensating weight or - if the safety device (13) is arranged on the compensating weight (4) - raise the load-carrying means, is limited (s_max).
4. Method according to one of claims 1 to 3, wherein the drive unit (3) of the elevator has a motor (40) which is controlled by a frequency converter, characterized in that the motor voltage and currents are determined by means of vector regulation and the magnetic flux and torque are regulated independently.
5. Method according to one of claims 1 to 4, characterized in that a control system is provided which, for the purpose of determining a direction of release, refers to the leading sign of a last-specified reference speed.
6. Method according to one of claims 1 to 4, characterized in that a control system is provided which, for the purpose of determining a direction of release, refers to the leading sign of the last-registered speed of the load-carrying means (2).
7. Method according to one of claims 1 to 6, characterized in that a travel distance of the load-carrying means (2), or of the compensating weight (4), or of the angle of rotation of the traction sheave (18), while the torque is acting on the suspension means (5), in order to - if the safety device (13) is arranged on the load-carrying means (2) - move the compensating weight downward, or - if the safety device (13) is arranged on the compensating weight (4) to move the load-carrying means downward - is measured and compared with a reference value (s_max), and the previous method steps are repeated if this reference value is not attained.
8. Method according to one of claims 1 to 6, characterized in that the torque that is actually generated in order to - if the safety device (13) is arranged on the load-carrying means (2) - move the compensating weight downward, or - if the safety device (13) is arranged on the compensating means (4) - to move the load-carrying means downward, is measured and compared with a reference value, and that, if this reference value is exceeded, the previous method steps are repeated.

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