EP1401757B2 - Method for preventing an inadmissibly high speed of the load receiving means of an elevator - Google Patents

Abstract

A method for preventing an inadmissibly high speed of a load receiving unit of an elevator, including the steps of supplying information about an actual position and an actual speed of the load receiving unit in an area of an entire travel way of the load receiving unit to a speed monitoring device by at least one measuring system, continuously comparing the actual speed with a speed limit value by the speed monitoring device, and activating braking measures if the speed of the load receiving unit exceeds a speed limit value. At least three different braking measures are successively triggered by the speed monitoring device.

Description

The invention relates to a method for preventing an impermissibly high travel speed of the load-receiving means of an elevator.

Regulations governing the construction and operation of lifts require the use of equipment and procedures which, at every stage of the lift operation, are designed to prevent an inadmissibly high traveling speed of the load-handling device with the utmost security.

Conventional lifts are equipped with a safety gear which, if the travel speed of the load handling device exceeds a defined speed limit, is activated by a speed limiter and brakes and stops the load handling device with the maximum delay.

US 6,170,614 B1 discloses an electronic speed limiting system, which continuously receives information from a position-measuring device about the current position of the load-receiving means and calculates from this the current speed. This current speed is constantly compared by a microprocessor with fixed programmed limit values which are constant over the entire driving range and which are assigned to specific operating modes of the elevator, for example an ascending or descending run. If the current speed of the lifting device exceeds the currently active limit, the electronic speed limiting system activates an electromagnetically operated safety gear that stops the load handling device.

The electronic speed limit system described has significant disadvantages. Each detected exceeding of the active limit leads to the triggering of the safety gear and thus to an interruption of the operation of the elevator, wherein in most cases the passengers can not leave the elevator before a skilled person has put the elevator back in operation or has brought the load handling device in the area of access. Any over-speeding thus results in a braking of the load-handling device with deceleration values in the maximum permissible range, which is very unpleasant for the passengers, causing anxiety and even frail persons can cause injury.

The present invention has for its object to provide a method for preventing an inadmissibly high speed of the lifting device of an elevator, with the help of which in some cases of detected overspeed interruptions can be avoided, passengers never included in the elevator and only in the extreme emergency of Exposure to the strong deceleration to be suspended by a safety gear.

This object is achieved by the method specified in claim 1. Advantageous embodiments and modifications of the invention will become apparent from the dependent claims.

The advantages achieved by the method according to the invention can essentially be seen in the fact that higher availability is achieved for the elevator installation, and that the elevator users are not unnecessarily frightened and blocked in the load-carrying means by avoiding catch braking, on the one hand, and no costs for unclamping on the other hand of the elevator incurred after a fall arrest.

In a preferred embodiment of the invention, a specific braking measure is triggered by the speed monitoring device when a speed limit assigned to this particular braking measure is exceeded. With this method, a safe and simple form of a multi-stage speed monitoring device can be realized.

According to a more cost-effective embodiment of the invention, a further braking measure is triggered in each case if a preceding braking measure has not led to a defined speed reduction within a defined time.

A safety-relevant particularly advantageous development of the invention is achieved in that in each case a further braking action is triggered when a braking action associated with this speed limit is exceeded, or if a previous braking action has not led within a defined time to a defined speed reduction. Both criteria are monitored simultaneously, and a further braking action is activated if one of the two criteria is met.

In elevators having a drive unit with a speed control device, a particularly advantageous embodiment of the method according to the invention results from the fact that one of the braking measures is that the speed monitoring device attempts to influence the speed control device in such a way that it reduces the drive speed of the load receiving means.

This avoids the intervention of a mechanical friction brake and the shutdown of the elevator in many cases.

A particularly simple and expedient proves to be an embodiment of the method described above, in which the reduction of the drive speed of the load receiving means is to be achieved by applying a fixed stored speed setpoint to a setpoint input of the speed control device.

Another braking measure which can be used with the method according to the invention is that in the case of a cable-driven elevator with a drive machine and a traction sheave, a friction brake acting directly or indirectly on the traction sheave is activated, which is to reduce the travel speed of the lifting device or to shut down this, wherein previously the prime mover is turned off. As a result, the load receiving means is braked with great certainty, so that the use of a safety gear can usually be avoided.

When using the method according to the invention in a hydraulically driven elevator installation, advantageous braking measures are that the speed monitoring device increasingly limits the flow of a hydraulic medium via a separate flow valve or activates a friction brake acting on a piston rod of a hydraulic lifter, thereby reducing or reducing the travel speed of the lifting device to be shut down.

In a further expedient development of the method, one of the braking measures is that a safety device is activated by the speed monitoring device, which is attached to the load-receiving means and, if activated, acts on rails permanently installed along the travel path and stops the load-handling device.

The invention consists in that the speed limit values associated with the individual braking measures, with which the speed monitoring device continuously compares the current driving speed, are dependent on the current position of the lifting device and include a reduction of the driving speed required in both end regions of the travel path. Moreover, these speed limits may also depend on a particular mode of operation (e.g., ramp travel, inspection, fault mode, etc.). This eliminates the need for conventional deceleration, control devices in both end regions of the travel path of the lifting device. In addition, so that the buffers that prevent in conventional lifts a hard impact of the lifting device at the lower and upper end of the track can be omitted or built much smaller, since the caused by the control delay of the lifting device is monitored safety relevant in the end of the route.

According to the invention, the speed limit values associated with the individual braking measures, with which the speed monitoring device continuously compares the current driving speed, are continuously calculated in accordance with the current position of the load receiving means by a microprocessor integrated in the speed monitoring device. In this case, on the one hand, the position-dependent, permanently programmed speed limit values and, on the other hand, information about the driving sequence supplied by the elevator control, in particular speed reductions in the case of landing stops, are included. This has the advantage that the speed monitoring device is also effective in these areas of reduced speed.

An additional advantageous development of the invention consists in the elevator automatically resuming normal operation or an evacuation mode following a successful braking action triggered by overspeed, if the type of last braking measure and the results of an automatically performed functional check of the safety-relevant components permit this.

A particularly preferred embodiment of the method according to the invention is that all the functions involved in this method take place using fail-safe concepts. Such concepts include, for example, redundant position and / or speed measuring devices, actuators for activating brake devices in fail-safe execution, data backup data transfer, redundant data processing by several, possibly different processors with comparison of results, etc. In case of inconsistencies appropriate safety measures are triggered. By applying such a fail-safe concept in the inventive method can be dispensed with complex mechanical Geschwindigkeitsbegrenzersysteme and additional delay control circuits in both areas of the travel end of the lifting device.

Fig. 1A

eine schematisch dargestellte Aufzugsanlage mit Seilantrieb, mit den für die Darstellung der Erfindung wichtigen Aufzugskomponenten

Fig. 1B

eine schematisch dargestellte Aufzugsanlage mit hydraulischem Antrieb, mit den für die Darstellung der Erfindung wichtigen Aufzugskomponenten

Fig. 2, 3

die Zusammenhänge zwischen dem Geschwindigkeitsverlauf bei Normalfahrt und den beim erfindungsgemässen Verfahren angewandten Geschwindigkeits-Grenzwerten

Fig. 4, 5

den Verfahrensablauf mit einer einzigen Geschwindigkeits-Grenzwertkurve

Fig. 6

eine schematische Darstellung der Geschwindigkeitsüberwachungseinrichtung für die Anwendung mit einer einzigen Geschwindigkeits-Grenzwertkurve

Fig. 7, 8

den Verfahrensablauf mit mehreren unterschiedlichen Geschwindigkeits-Grenzwertkurven

Fig. 9

eine schematische Darstellung der Geschwindigkeitsüberwachungseinrichtung für die Anwendung mit mehreren Geschwindigkeits-Grenzwertkurven

In the following the invention will be explained in more detail by means of examples and with reference to the accompanying drawings. Showing:

Fig. 1A

a schematically illustrated elevator system with cable drive, with the important for the representation of the invention elevator components

Fig. 1B

a schematically illustrated elevator system with hydraulic drive, with the important for the representation of the invention elevator components

Fig. 2, 3rd

the relationships between the velocity course during normal driving and the speed limit values used in the method according to the invention

Fig. 4, 5

the procedure with a single speed limit curve

Fig. 6

a schematic representation of the speed monitor for the application with a single speed limit curve

Fig. 7, 8

the procedure with several different speed limit curves

Fig. 9

a schematic representation of the speed monitoring device for the application with multiple speed limit curves

Fig. 1A schematically shows an elevator system with cable drive. An elevator shaft 1 with a machine room 2 and storey accesses 3 can be seen. In the machine room 2, a drive unit 4 is arranged which carries and drives a lift cage (load-carrying means) 8 guided on guide rails 7 via a traction sheave 5 and carrying cables 6. The drive unit 4 has a drive motor 9 with an electromechanical drive brake 10. Direction of rotation, speed and drive torque of the drive motor 9 are controlled by a speed control device 14, wherein the speed control device receives control commands from an elevator control 15. At the elevator car 8, for example, two electromagnetically activated safety gear 18 are mounted, with which the elevator car 8 can be braked and stopped in case of emergency. Denoted at 20 is a scale extending over the entire travel path of the elevator car 8, which has a plurality of binary coded parallel code tracks. These code tracks are scanned by a position detection device 21 fixed to the elevator car 8, which continuously decodes the current absolute position of the elevator car 8 from the binary signal states and transmits these to the elevator control 15. By differentiating the position value differences over time, the current travel speed of the elevator car 8 is calculated in the elevator control 15, which serves, inter alia, as actual value feedback for the speed control device 14 of the drive motor 9. A speed monitoring device 24 has the task of detecting an impermissibly high driving speed of the elevator car 8 and if necessary to initiate suitable countermeasures. Elevator control 15, speed control device 14 and speed monitoring device 24 are according to Fig. 1A connected via signal and / or data lines, but this does not exclude that these devices can be integrated together in a larger unit. The data and signal transmission between these devices on the one hand and the position detection device 21 and the safety gears 18 on the other hand takes place via a suspension cable 25 rolling off between the elevator car 8 and the shaft wall.

Fig. 1B schematically shows an elevator system with hydraulic drive. Evident are an elevator shaft 1 with a machine room 2 and floor access 3. In the engine room 2, a hydraulic drive unit 50 is arranged, which drives the piston rod 52 of a hydraulic jack 51, which has a deflection roller 53 at its upper end. About this pulley 53 carry suspension cables 54, which are each secured with its one end to a fixed point 55 on the lifter 51 and carry with its other end an elevator car (load-carrying means) 8 and drive, which is guided on guide rails 7. The drive unit 50 is equipped with a speed control device 14, which determines, for example via a variable displacement pump 56, the amount and direction of the oil flow which moves the hydraulic lifter 51, wherein the speed control device 14 receives control commands from an elevator control 15. At the elevator car 8, for example, two electromagnetically activated safety gear 18 are mounted, with which the elevator car 8 can be braked and stopped in emergencies, for example in a suspension rope break. At the upper end of the lifter cylinder 57 an electromagnetically activatable, acting on the piston rod 52 clamp brake 58 is attached. From detail X it can be seen that between the caliper brake 58 and the piston rod 52, when the magnet 59 is de-energized, a braking force can be generated by the force of a compression spring 60. This braking force is able to brake the elevator car 8, for example, in the case of failure of the speed control of the hydraulic drive. The magnet 59 is controlled by the speed monitor 24. The hydraulic drive unit 50 has, among other valves on a safety flow valve 61 which can be activated by the speed monitor 24 at detected overspeed of the elevator car 8, the safety flow valve in such a case, the oil flow is continuously reduced so that the elevator car 8 with is decelerated defined delay. Denoted at 20 is a scale extending over the entire travel path of the elevator car 8, which has a plurality of binary coded parallel code tracks. These code tracks are scanned by a position detection device 21 fixed to the elevator car 8, which continuously decodes the current absolute position of the elevator car 8 from the binary signal states and transmits these to the elevator control 15. By differentiating the position value differences over time, the current travel speed of the elevator car 8 is calculated in the elevator control 15, which among other things is used as actual value feedback for the speed control device 14 of the drive motor 9 is used. A speed monitoring device 24 has the task of detecting an impermissibly high driving speed of the elevator car 8 and if necessary to initiate suitable countermeasures. Elevator control 15, speed control device 14 and speed monitoring device 24 are according to Fig. 1B connected via signal and / or data lines, but this does not exclude that these devices can be integrated together in a larger unit. The data and signal transmission between these devices on the one hand and the position detection device 21 and the safety gears 18 on the other hand takes place via a suspension cable 25 rolling down below the elevator car 8.

Fig. 2 12 shows a diagram whose vertical axis represents the travel path (position in the shaft) and whose horizontal axis represent the travel speed of the elevator car 8, which illustrates the relationship between the speed profile during normal travel and the speed limit values monitored by the speed monitor 24. Entered are a curve with a normal driving speed curve 27 in a journey with intermediate stop and a speed limit curve 28, which also includes the mandatory in both Fahrweg end areas speed reduction. The values of the speed limit curve 28 are in this embodiment for each position of the elevator car 8 in the elevator shaft 1 fixed in the speed monitoring device 24, for example in the form of a table, programmed. Depending on the execution of the speed monitoring method, a speed limit curve 28 or a plurality of different speed limit curves 28 associated with different braking actions are stored. Depending on possibly activated special operating modes (eg ramp travel, inspection, fault mode, etc.), these position-dependent speed limit curves can run differently.

Fig. 3 shows a same diagram as Fig. 2 However, wherein the speed limit curve 28 in the area between the end-of-travel areas additionally includes the speed course when stopping on intermediate storeys. The limits for these ranges are continuously calculated in the speed monitor 24 based on speed setpoint information provided by the elevator controller 15. Here, too, several speed limit curves with different permissible deviations can be used and, depending on any activated special operating modes (eg ramp travel, inspection, error mode, etc.), may also be different, but this is not shown here.

4 and 5 show in the way / speed diagram the flow of the inventive method with only a single speed limit curve. In Fig. 4 at 27 (for comparison) is a curve with a normal vehicle speed curve and at 28 the speed limit curve is shown. A registered actual speed 29 runs in such a way that it exceeds the speed limit curve 28 outside of the travel end regions at curve point 30. The speed monitoring device 24.1 recognizes this and activates a first braking measure, ie in the present example it tries to cause the speed control device 14 to reduce the drive speed with a predefined delay in accordance with the controller brake curve 33. This first braking measure does not necessarily lead to the standstill of the elevator. If the braking measure with the cruise control device 14 has caused a travel speed below the speed limit curve 28, and if a system test device integrated in the elevator control 15 does not report a relevant fault, the elevator can continue its travel as scheduled. After a defined short time, which is measured from the moment of activation of the first braking measure, checks the speed monitor 24.1, if the speed limit curve 28 is still exceeded, and optionally activates (at curve point 31) a second braking action (the mechanical drive brake 10 on the drive motor 9 in Fig. 1A or the forceps brake 58 acting on the piston rod 52 Fig. 1B ), whereby the elevator according to the drive brake curve 34 is to be braked. Detects the speed monitoring device 24.1 at the end of another short waiting time that the speed limit curve 28 is still exceeded, it triggers (at curve point 32) according to this embodiment last braking action, ie it activates the electromagnetic triggering device 18, the elevator shut down according to the safety brake curve 35.

In Fig. 5 is shown in the way / speed diagram, as it comes in the inventive method with a single speed limit curve 28 for triggering braking measures when the actual speed 29 of the elevator, without exceeding the rated speed, in a track end area or floor stop Range exceeds the falling speed limit curve 28 here, because, for example, the required here reduction of the actual speed does not occur. After the first braking action has been triggered by the speed monitoring device 24.1 in item 30, the same operations as described above take place Fig. 4 are described.

Fig. 6 schematically shows an inventive electronic speed monitoring device 24.1, as for the method with a single Speed limit curve 28 is used. It consists essentially of a limit value module 38, a comparator 39 and a reaction generator 40.1 with a timer 44. The speed monitoring device 24.1 receives on the one hand via its position data input 41 continuously generated by the position detection device 21 information about the current position of the elevator car 8 in the elevator shaft. On the other hand, it receives via its actual speed input 42 from the elevator control 15 information about the current actual speed of the elevator. From a table stored in the limit value module 38, the speed limit values assigned to each shaft position are continuously read out and compared in the comparator 39 with the current actual speed.
As soon as and as long as the comparator 39 determines that the current actual speed exceeds the position-dependent defined current speed limit, it sends a corresponding overspeed signal to the reaction generator 40.1. This activates via one of its brake signal outputs 43.1, 43.2, 43.3 immediately the first braking measure, ie, to a setpoint input of the speed control device 14 is a fixed speed setpoint or a permanently stored delay setpoint applied. At the same time, the timer 44 is started with an adjustable waiting time. If the overspeed signal is still pending after the waiting time has expired, the reaction generator 40.1 activates the next following braking action and restarts the timer 44. If the speed limit value is exceeded even after the second waiting time has elapsed, a last braking measure or the safety gear is activated ,

According to an embodiment variant of the method according to the invention, the speed limit value 28 supplied to the comparator 39 by the limit value module 38 does not always correspond to the position-dependent speed limit values permanently stored in the tables of the limit value module, but the stored speed limit values are in the areas where the elevator control 15 predetermines a reduced speed setpoint, continuously adapted by a processor integrated in the limit value module 38 to these reduced setpoint values. This happens especially when stopping on a floor. The required information from the elevator control 15 receives the limit value module via a data line 45.

Of course, the inventive method can also be applied to elevator systems with more than three different braking measures.

FIGS. 7 and 8 show in the way / speed diagram the flow of the inventive method with several different speed limit curves 28, which are each assigned to different braking measures. In Fig. 7 For comparison, the graph again shows a curve 27 representing a normal vehicle speed profile. In addition, three speed limit curves 28 are entered. An assumed actual speed 29 is such that it exceeds the first speed limit curve 28.1 above the nominal speed and outside a track end area or a floor stop area at curve point 46. The speed monitoring device 24.2 recognizes this and activates a first braking action, ie, in the present example it tries to cause the speed control device 14 to reduce the drive speed with a predefined delay in accordance with the regulator brake curve 33. Even in this case, this first braking measure does not necessarily lead to the standstill of the elevator. If the second speed limit curve 28.2 is not also exceeded and the system test device integrated in the elevator control 15 does not report a relevant error, the elevator can continue its travel according to the program. However, if the first braking measure is not or not sufficiently effective, so that the second speed limit curve 28.2 is exceeded, the speed monitoring device 24.2 activates a second braking measure at the curve point 47 (the mechanical drive brake 10 on the drive motor 9 in FIG Fig. 1A or the forceps brake 58 acting on the piston rod 52 Fig. 1B ), whereby the elevator according to the drive brake curve 34 is to be braked to a standstill. If this braking measure also does not reduce the speed or does not sufficiently reduce it, then the speed monitoring device 24.2 triggers the last braking action according to this exemplary embodiment at curve point 48, ie activates the electromagnetically triggered safety gear 18, which stops the elevator according to the safety brake curve 35.

In Fig. 8 is shown in the way / speed diagram, as it comes in the inventive method with multiple speed limit curves 28.1, 28.2, 28.3 for triggering braking measures when an assumed actual speed 29 of the elevator, without exceeding the rated speed, in a guideway End area or floor stop area one or more of the falling here speed limit curves 28.1, 28.2, 28.3 exceeds because, for example, the required here reduction of the actual speed does not occur. After the first braking measure has been triggered by the speed monitoring device 24.2 at the curve point 46, the same operations take place as described above Fig. 7 are described.

Fig. 9 schematically shows the inventive electronic speed monitoring device 24.2, as for the in connection with FIG. 7, 8 described method with multiple speed limit curves 28.1, 28.2, 28.3 is used. It basically consists of the same modules as those mentioned above Fig. 6 described speed monitoring device 24.1, but for each of the speed limit curves to be monitored 28.1, 28.2, 28.3 per a threshold module and each one comparator are available. It thus contains three limit modules 38.1, 38.2, 38.3 and three comparators 39.1, 39.2, 39.3 and a common reaction generator 40.2. On the one hand, via its actual speed input 42, the speed monitoring device 24.2 continually receives information about the current position of the elevator car 8 in the elevator shaft 1 from the position detection device 21. Speed of the elevator. In each of the three limit modules 38.1, 38.2, 38.3 position-dependent speed limit values are stored in a respective table, wherein the values contained in each one of the tables one with Fig. 7, 8 map three speed limit curves 28.1, 28.2, 28.3, ie, each of the tables is assigned to one of the three different braking measures and contains for each position of the elevator in the shaft one of these braking measure associated speed limit.

During an elevator journey, the speed limit values for the three different braking measures corresponding to the current shaft position of the elevator car are continuously read from each of the three tables stored in the limit module 38.1, 38.2, 38.3, and in the comparators 39.1 assigned to each of the limit module 38.1, 38.2, 38.3. 39.2, 39.3 compared with the current actual speed. As soon as and as long as one of the comparators 39.1, 39.2, 39.3 ascertains that the current actual speed exceeds the position-dependent speed limit value stored in the respectively associated table, it sends an overspeed signal to the reaction generator 40.2. This activates via one of its brake signal outputs 43.1, 43.2, 43.3 immediately that of the three possible braking measures, which is assigned to the signal-giving comparator and the corresponding limit value module.

According to a variant of the associated with Figure 9 described inventive method with several different speed limit curves 28.1, 28.2, 28.3, the speed limit values supplied by the three limit modules 38.1, 38.2, 38.3 to the comparators 39.1, 39.2, 39.3 do not always correspond to the position-dependent speed permanently stored in the tables of the limit module Limit values, but the stored speed limit values are continuously adjusted in the track areas where the elevator control 15 a reduced speed setpoint, by processors in the limit modules 38.1, 38.2, 38.3 these reduced setpoints. This happens especially when stopping on a floor. The information required for this purpose by the elevator control 15 is received by the limit value modules 38.1, 38.2, 38.3 via a data line 45.

Of course, the whole related to Fig. 9 described method can also be used for lifts with more than three different braking measures.

A speed monitoring method that meets particularly high safety requirements can be realized by the method with time-dependent reaction control according to Fig. 4, 5, 6 is combined with the method with several different speed limit curves 28 according to Fig. 7, 8, 9 , wherein in each case a further braking action is triggered when the previous braking action has not led within a defined time to a defined speed reduction, or if a further braking action associated with this position-dependent speed limit is exceeded.

• Redundanz bei Positions- oder Geschwindigkeitserfassungseinrichtungen, bei Datenverarbeitungsprozessoren, bei Aktoren für die Aktivierung von Bremseinrichtungen, usw.
• Datensicherungsverfahren bei Datenübertragung
• parallele Datenverarbeitung durch mehrere, eventuell unterschiedliche Prozessoren, mit Resultatevergleich und Auslösung von geeigneten Sicherheitsmassnahmen im Falle von auftretenden Fehlern.

In order for the method according to the invention to be able to meet the high safety requirements for an elevator system, at least all functions involved in the activation of the safety gear are to be carried out with safety relevance. Suitable measures for implementing such "fail-safe" concepts are known to the person skilled in the art and include, for example:

• Redundancy in position or speed detection devices, in data processing processors, actuators for activation of braking devices, etc.
• Data backup method
• Parallel data processing by several, possibly different processors, with the same result and triggering of appropriate safety measures in case of errors.

In order to ensure a safe process even in case of power failure or failure of the control power supply, the important for the inventive method circuits in the event of a breakdown are fed by suitable emergency power supplies, for example by means of batteries or capacitors.

Claims (12)

1. Method for preventing an inadmissibly high speed of the load receiving means (8) of an elevator in which
   in the area of the entire travel way of the load receiving means (8), information about the actual position and the speed of the load receiving means is supplied to a speed monitoring device (24.1; 24.2) by at least one measuring system (20, 21) and the actual speed is continuously compared with a speed limit value (28; 28.1, 28.2, 28.3) by this speed monitoring device (24.1; 24.2) and braking measures are activated if the speed of the load receiving means (8) exceeds a speed limit value (28; 28.1, 28.2, 28.3),
   in which at least three different braking measures are successively triggered by the speed monitoring device (24.1; 24.2),
   in which the speed limit values (28; 28.1, 28.2, 28.3) assigned to the braking measures with which the actual speed (29) is continuously compared by the speed monitoring device (24, 24.1; 24.2), depend on the actual position of the load receiving means (9) and contain a required speed reduction in both end zones of the travel way,
   in which the speed limit values (28; 28.1, 28.2, 28.3) assigned to the braking measures with which the actual speed (29) is continuously compared by the speed monitoring device (24, 24.1; 24.2), are continuously calculated by a micro processor according to the actual position of the load receiving means (9), taking into consideration the permanently programmed speed limit values (28) as well as information from the elevator controls (15) about the planned travel operation (45).
2. Method according to claim 1, characterized in that, in each case one of the braking measures is activated when a speed limit value (28; 28.1, 28.2, 28.3) assigned to this braking measure, is exceeded.
3. Method according to claim 1, characterized in that, in each case, a further braking measure is activated if a preceding braking measure has not produced the defined speed reduction within a certain period.
4. Method according to claim 1, characterized in that, in each case, a further braking measure is activated if a speed limit value (28.1, 28.2, 28.3) allocated to this braking measure is exceeded or if a preceding braking measure has not produced the defined speed reduction within a certain period.
5. Method according to one of the claims 1 to 4, characterized in that in case of an elevator comprising a drive unit (4) for the load receiving means (8) including a speed control device (14), a braking measure consists of an attempt by the speed monitoring device to influence the speed control device (14) of the drive unit (4) in such a way that it reduced the drive speed of the load receiving means (8).
6. Method according to claim 5, characterized in that the reduction of the drive speed of the load receiving means (8) is to be achieved by a permanently stored set speed value or a permanently stored set delay value being applied to a set value input of the speed control device (14).
7. Method according to one of the claims 1 to 6, characterized in that in case of a cable-pulled elevator with a drive machine (4), a driving wheel (5) and a pulling cable (6), a further braking measure consists of a friction brake (10), acting directly or indirectly on the driving wheel (5) being activated by a speed monitoring device (24; 24.1; 24.2).
8. Method according to one of the claims 1 to 6, characterized in that in case of an elevator with a load receiving means (8) guided along guide rails (7), a further braking measure consists of friction brakes acting between the load receiving means (8) and its guide rails (7) being activated by the speed monitoring device (24; 24.1; 24.2).
9. Method according to one of the claims 1 to 6, characterized in that in case of a hydraulically operated elevator, another braking measure consists of the flow of a hydraulic medium determining the movement of a hydraulic lifter (51) being increasingly restricted by a speed monitoring device (24) through a flow valve (61) or of a friction brake (58) acting on a piston rod (52) of a hydraulic lifter that is activated by the speed monitoring device (24).
10. Method according to one of the claims 1 to 9, characterized in that a braking measure consists of at least one safety catch (18) being activated by the speed monitoring device (24; 24.1; 24.2), with said safety catch being mounted on the load receiving means (8) and acting on rails permanently installed along the travel way and stopping the load receiving means (8).
11. Method according to one of the claims 1 to 10, characterized in that after a successful braking measure triggered by an excessive speed, the elevator automatically returns to its normal operation or enters an evacuation operation as long as the type of the last braking measure and the results of an automatically carried out functional test of the safety-relevant components allow this.
12. Method according to one of the claims 1 to 11, characterized in that for the determination of the position and the speed of the load receiving means, the comparison of the speed with the speed limit values as well as for the activation of the braking measures, a comprehensive fail safe concept is used.

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