Lifting mechanism and control method

Abstract

The lifting mechanism (10) according to the invention has a drive system (14) with an electric motor (15) for applying a drive torque (M_A), by way of which the load can be lifted and lowered, a load-controlled brake means (16) for applying a braking torque (M_S), by way of which the load can be held, a gear mechanism (17) and a control means (18) which is connected communicatively to the load-controlled brake means (16) and the electric motor (15), wherein the control means (18) is designed to actuate the load-controlled brake means (16) in such a way that, above all in the case of slow lifting movements, the braking torque (M_S) of the load-controlled brake means (16) is greater than the load torque (M_L) of the load and smaller than the drive torque (M_A) of the electric motor (15). The load-controlled brake means (16) is activated in a predefined rotational speed range (n_b), in which the electric motor (15) operates counter to the braking torque (M_S) of the load-controlled brake means (16).

Description

Elmar Zürn 21 June 2023 Keltergasse 63 ZUER P001 paln 74653 Künzelsau Keyword: Safe drive system for lifting applications Lifting device and control method

[0001] The invention relates to lifting devices, in particular load balancing devices with a drive system and a traction means connected to the drive system for lifting, lowering and holding a load attached thereto, as well as a control method for the lifting device.

[0002] Hoists are used to lift, lower, and hold loads using chains, ropes, or other traction devices. The lifting device is driven by an (electric) motor, with a gearbox typically located between the traction device and the motor.

[0003] For complex assembly and disassembly processes, lifting devices are often used where the user can bring the load into the desired position and / or orientation with slow and safe lifting movements of the lifting device, so-called "load balancers", hereinafter referred to as load balancing devices.

[0004] These load balancing devices typically have a load suspension device (as described in DE 102012 103 515 A1). A control handle with a force sensor is attached to the load suspension device, whose signals serve as control signals for the electric motor.

[0005] US 6,386,513 B1 describes another such load balancing device in which the force applied by the operator is also determined with a force sensor and is used to control the drive of the load balancing device.

[0006] Furthermore, the publications DE 102014 101 655 A1 and DE 102014 101 654 B4 describe drive trains of lifting equipment with hysteresis couplings, which are used to limit torque in emergency failures.

[0007] However, especially when people are in the working area of ​​the lifting device, increased safety requirements are placed on the lifting device and its drive train. Sagging or even falling of the load must be avoided at all costs in such applications.

[0008] Currently, the drive trains of such lifting devices predominantly use synchronous motors with permanent magnets in the rotor and measuring devices for determining the angular position and speed of the rotor. However, such synchronous motors are cost-intensive and require a relatively large installation space. Especially in smaller lifting devices with lower load capacities, such as chain hoists, the installation space for the electric motor is very limited.

[0009] Based on this, the object of the invention is to provide an improved lifting device and an improved control method for the lifting device, with which especially slow lifting movements are possible safely.

[0010] This object is achieved by the lifting device according to claim 1 and the control method for a lifting device according to claim 15:

[0011] The lifting device according to the invention comprises a drive system with a traction mechanism connected to the drive system for raising, lowering, and holding a load attached thereto. The lifting device is preferably designed as a load balancing device. The drive system of the lifting device comprises an electric motor for applying a drive torque with which the load can be raised and lowered, a load braking device for applying a braking torque with which the load can be held, a transmission, and a control device in communication with the load braking device and the electric motor.

[0012] The control device is designed to control the load braking device in such a way that the braking torque of the load braking device is greater than the load torque of the load and less than the drive torque of the electric motor when the electric motor is in a predetermined speed range (close to zero speed) which includes zero speed.

[0013] The speed range in which the load braking device is activated by the control device is particularly close to zero speed, i.e. a speed equal to zero. The speed range can be symmetrical or be defined asymmetrically around the zero speed. In addition to the zero speed, the speed range can in particular include negative speeds, whereby the load braking device is activated by the control device when the load is (slowly) lowered. Additionally or alternatively, the speed range can include positive speeds, whereby the load braking device is also activated by the control device when the load is (slowly) raised. The control device can contain several modules, such as a frequency converter for controlling the electric motor and a speed detection unit. The frequency converter contained in the control device does not have to meet any increased safety requirements.

[0014] Activating the load braking device in the predetermined speed range makes it possible to use electric motors without their own holding torque, such as preferably three-phase asynchronous motors or synchronous motors without precise rotor position detection, even for applications with high safety requirements. Frequency converters with V / f characteristic control without speed feedback and with V / f vector control with or without speed feedback can be used to control the electric motor. The predetermined speed range is preferably defined such that it includes positive speeds when frequency converters with V / f characteristic control are used in the control device. Activating and / or deactivating the load braking device requires a certain, short time.The control of the electric motor by the control device preferably requires a shorter time than the activation and / or deactivation of the load braking device. This allows for a faster response, particularly during lifting. The load is to avoid jerking of the lifting device when the load braking device is deactivated if the speed of the electric motor leaves the speed range in which the load braking device was triggered.

[0015] Frequency converters without speed feedback are particularly preferable for smaller hoists with lower load capacities, as they require comparatively less space. At low control frequencies, for example, less than approximately 20% of the maximum control frequency, the resistive component of the stator windings predominates. At low motor voltages, this can lead to a drop in the flowing motor currents and thus to a drop in torque during slow lifting movements. By activating the load braking device in this speed range, even simple frequency converters with V / f characteristic control can be used without increasing the risk of a load drop.

[0016] A special feature of the lifting device according to the invention is that the lifting device has a load braking device that is controlled in such a way that it is activated at low speeds of the electric motor, so that the electric motor works against the load braking device. The braking torque of the load braking device is, at least in this speed range, greater than the load torque of the load. The load can be held by the load braking device, even without the electric motor applying a drive torque. When the load is slowly lowered, the electric motor applies a drive torque that is at least greater than the braking torque of the load braking device. When the load is slowly raised, the electric motor applies a drive torque which is greater than the sum of the braking torque of the load braking device and the load torque of the load, whereby the braking force of the load braking device can be regulated depending on the drive torque.

[0017] The load braking device is preferably designed as a controllable friction or hysteresis brake or as a magnetic powder brake. Hysteresis or magnetic powder brakes or permanent magnet brakes are particularly preferred, as they are subject to no or almost no wear, enable virtually silent operation, and have only low power consumption during operation. Furthermore, with these types of braking devices, the applied braking torque is adjustable. The transmission is preferably a non-self-locking transmission, for example, with a gear ratio greater than zero.

[0018] In particular, the control device is configured to activate the load braking device when the load is lowered if the speed of the electric motor exceeds a lower speed limit, i.e., when the speed of the electric motor is greater than the lower speed limit. When the load is lowered, a negative speed exists, as defined above. In this situation, the drive torque of the electric motor counteracts the braking torque. The lower speed limit can, for example, be approximately 10% of the maximum speed of the electric motor.

[0019] In particular, the control device is designed to activate the load braking device when lifting the load if the speed of the electric motor falls below an upper speed limit. The upper speed limit can, for example, be zero speed, so that the electric motor does not additionally work against the braking torque of the load braking device when lifting the load. However, the upper speed limit can also be greater than zero speed, for example at approximately 10% of the maximum speed of the electric motor. In this case, the braking torque and the load torque counteract the drive torque. In this embodiment, the electric motor is designed in particular such that the drive torque is greater than the sum of the rated load torque and the braking torque. The above-mentioned speed range is defined in particular by the lower and upper speed limits.

[0020] In one embodiment, the lifting device is designed without a clutch, so that no clutch device is arranged between the output shaft of the electric motor and the input shaft of the transmission. In an alternative embodiment, the lifting device has a clutch device, which can be designed as a positive-locking clutch device, such as a claw or tooth clutch, or a rigid clutch device. In another embodiment, the lifting device has a non-positive-locking clutch device. The electric motor has, in particular, an output shaft, which is mechanically coupled to an input shaft of the transmission via this clutch device. The clutch device can, for example, be a torque-limiting clutch device, such as a slip or hysteresis clutch.The torque-limiting clutch device limits the drive torque of the drive system. In this embodiment, the drive system is not clutchless. If a clutch device is provided, it divides the drive system into an engine side and a transmission side.

[0021] In one variant, the load braking device is arranged on the motor side, whereby the load braking device is mechanically coupled to the output shaft of the electric motor.

[0022] In a further (preferred) variant, the load braking device is arranged on the transmission side, wherein the load braking device is mechanically coupled to the input shaft of the transmission. The arrangement of the load braking device on the transmission side can, in particular, improve or balance the weight distribution of the drive system. For example, the weight of the load braking device, including any service brake device and centrifugal switch, can at least substantially correspond to the weight of the electric motor, including any coupling device. The load braking device is controlled by the control device such that it is activated in a speed range that is greater than the lower speed limit and less than or equal to zero.Advantageously, the electric motor can be designed such that the drive torque of the electric motor can be smaller than the sum of the rated load torque and the braking torque of the load braking device, allowing smaller electric motors to be used to drive the lifting device. The lifting device can thus be designed without a coupling device or with a rigid coupling device, as with cable hoists or winches. Furthermore, the load braking device allows for checking the The functionality of the coupling device can be checked, especially if the coupling device is designed as a torque-limiting clutch, such as a slip clutch. The braking torque of the load braking device is proportional to the applied voltage. For maintenance purposes, the coupling device can be checked by controlling the load braking device via an appropriate control system, testing whether the coupling device exceeds or falls below a set torque. If the coupling torque deviates from the set torque, the coupling torque setting can be corrected.

[0023] Furthermore, the lifting device has, in particular, a service brake device arranged on the transmission side. The service brake device can be designed to transmit a service brake torque to a transmission input shaft. The service brake torque is greater than the load torque of the load, whereby the safety of the drive system can be further increased. The service brake device is, in particular, designed to be activated when the load is not held at a constant height by the load brake device after a predetermined, in particular longer, period of time. A longer period of time is, for example, 19 seconds, 15 seconds, 20 seconds or longer. This means that after the last adjustment, the load brake device holds the load suspended for a predetermined, in particular longer, period of time; after this time has elapsed, the service brake device takes over the load.

[0024] Preferably, the control device is communicatively connected to the service brake device. The control device can be configured to The service brake device can be controlled in such a way that it applies a service brake torque when the speed is at least substantially equal to zero speed, preferably for a predetermined period of time. Furthermore, the control device can be configured to activate the service brake device when the speed exceeds a maximum speed limit. This can also further increase the safety of the drive system.

[0025] Preferably, the control device is designed to regulate the braking torque of the load braking device as a function of the load torque.

[0026] The control device is particularly designed to adapt the speed range defined by the lower and upper speed limits to the load torque. In particular, the braking torque applied by the load braking device can be changed by control signals received by the control device.

[0027] The drive torque of the electric motor is preferably designed to be at least as large as the sum of the rated load torque and the braking torque of the load braking device, so that when the braking device is activated, the load can still be lifted by the electric motor. The drive torque can be at least a factor of two greater than the load torque.

[0028] It is preferred that the control device is designed to gradually reduce the braking torque of the load braking device while the drive torque of the electric motor is not equal to zero. The deactivation of the load braking device thus takes place as smoothly as possible. In particular, the braking torque of the load braking device when lifting the load can be reduced to the same extent as the drive torque of the electric motor increases, so that the smoothest possible transition is achieved when changing the state of the load braking device, for example from an activated state of the load braking device in which the load braking device applies a maximum braking torque, to a deactivated state of the load braking device in which the load braking device applies at least substantially no braking torque.

[0029] The lifting device, in particular, has a centrifugal switch that is mechanically coupled to the input shaft of the transmission on the operating side. The centrifugal switch is preferably communicatively connected to the control device and / or the service brake device. If the load slips and the input shaft of the transmission has such a high speed that the centrifugal switch is triggered, the service brake device can be activated directly, thereby further increasing the safety of the drive system.

[0030] Preferably, the lifting device also has a speed detection unit connected to at least one speed sensor. The speed detection unit can be configured to provide a speed signal to the control device and / or the load braking device. The speed detection unit can also be included in the control device. The control device comprises, in particular, a frequency converter configured to control the electric motor and, in doing so, to take into account speed signals from the speed detection unit. Alternatively, the speed detection unit can also transmit the speed signal directly to the load braking device, separate from the control device, whereby the load braking device is active when the speed is within the predetermined speed range.

[0031] The method according to the invention for a lifting device, in particular for the lifting device of the above type, comprises applying a braking torque with a load braking device which is greater than the load torque of the load and less than the drive torque of an electric motor when the electric motor is in a predetermined speed range which includes the zero speed.

[0032] All features and advantages described with respect to the lifting device according to the invention are also applicable to the control method according to the invention.

[0033] Further details of advantageous developments or details of the invention can be found in the drawings of the description and the dependent claims. They show:

[0034] Figure 1 shows a schematic overall view of a lifting device,

[0035] Figure 2 shows an example of the drive system of the lifting device according to Figure 1, in schematic principle representation,

[0036] Figure 3 shows a second embodiment of the drive system of the lifting device according to Figure 1, in a schematic principle representation,

[0037] Figure 4 shows a third embodiment of the drive system of the lifting device according to Figure 1, in a schematic principle representation,

[0038] Figure 5 shows a fourth embodiment of the drive system of the lifting device according to Figure 1, in a schematic principle representation

[0039] Figure 6 Voltage-frequency characteristic of a frequency converter and

[0040] Figure 7 Speed-torque characteristics of the drive system during operation.

[0041] Figure 1 shows a lifting device 10 which is designed in particular as a load balancing device. The lifting device 10 has a traction means 11, at the end of which a load-bearing device 12 is attached. The traction means 11 can, for example, be designed in the form of a round-link chain, another chain, a rope, or the like. The traction means designed as a chain runs over a pocket wheel 13 which is connected on the operating side to a drive system 14 of the lifting device 10. The drive system 14 of the lifting device 10 has an electric motor 15 and a load braking device 16. The electric motor 15 is in particular a three-phase asynchronous motor.

[0042] The drive system 14 also includes a gearbox 17. The gearbox 17 can be a reduction gear that converts a high motor speed into a low speed of the pocket gear 13 to raise and lower loads. The gearbox 17 is preferably a non-self-locking gear transmission.

[0043] A (motor-side) load braking device 16 is connected to the drive system 14. The drive system 14 also has at least one control device 18, which is communicatively connected to the load braking device 16 and the electric motor 15 in order to control them. The load braking device 16 can be designed as a friction brake. However, the load braking device 16 is preferably designed as an electrically excited hysteresis brake or magnetic powder brake or permanent magnet brake. The braking effect of the hysteresis brake or magnetic powder brake is achieved by energizing its excitation coil(s). In the permanent magnet brake, the braking effect is canceled by energizing the excitation winding. In addition, the drive system 14 can have a service braking device 19, which is arranged on the transmission side. The service braking device 19 can, for example, be a switchable brake.

[0044] Figure 2 shows a first embodiment of the drive system 14. The drive system 14 has an electric motor 15 with an output shaft 20. The load braking device 16 is coupled to the output shaft 20 of the electric motor.

[0045] The output shaft 20 of the electric motor 15 is also mechanically connected to a clutch device 21. The clutch device 21 can be configured as a slip or hysteresis clutch that limits the maximum drive torque M_A of the electric motor 15. The clutch device 21 is also mechanically coupled to the input shaft 22 of the transmission 17. A service brake device 19 is provided on the input shaft 22 of the transmission 17 in Figure 2.

[0046] The gear 17 also has an output shaft 23, which is mechanically connected to the pocket wheel 13, on which the chain runs as a traction means 11. In the event that the drive system 14 of the lifting device 10 is designed without a gear 17, the service brake device 19 can also be mounted directly on the output shaft 23 of the drive system 14.

[0047] The control device 18 is designed to activate or control the load braking device 16 depending on the speed n of the electric motor 15.

[0048] The load braking device 16 is activated by the control device 18 when the current speed n is within a predetermined speed range n_b, which is particularly close to the zero speed n_0. The load braking device 16 can also be activated when the speed n of the electric motor 15 is above a maximum motor speed n_max. The control device 18 is configured to receive a target speed n_s and generate a corresponding voltage signal for the winding of the electric motor 15.

[0049] The target speed n_s can be specified to the control device 18 from outside. The control device 18 can, for example, contain at least one frequency converter. Regardless of the type of frequency converter of the control device 18, it is designed to regulate the electric motor 15 depending on the target speed n_s. The control device 18 in Figure 2 is also designed to control the service brake device 19 depending on whether the value of the target speed n_s is greater than zero. If the drive system 14 has a clutch device 21, overloading of the drive is reliably avoided because the clutch torque limits the maximum torque delivered by the electric motor 15 to the output shaft 20. The clutch torque can, for example, correspond to 1.1 to 1.6 times the maximum rated load torque M_L.

[0050] The drive system 14 shown in Figure 2 also has a centrifugal switch 26, which is mechanically coupled to the input shaft 22 of the transmission 17. The centrifugal switch 26 sends a signal to the control device 18 when a predetermined threshold value for the speed of the input shaft 22 of the transmission 17 is exceeded. When the centrifugal switch 26 is triggered, the control device 18 controls the service brake device 19 such that it applies the service brake torque M_B. In the event that the clutch device 21 fails, the service brake device 19 can thus brake the slipping load and prevent a load drop or an unintentional lowering of the load.

[0051] The service brake device 19 can also be activated by the control device 18 when the speed of the electric motor 15 is at least substantially equal to zero for a predetermined period of time T, for example, for a period of time T of 20 seconds or longer. In this case, no adjustment takes place for this predetermined period of time T, so that after the expiration of the period of time T, the service brake device 19 can apply the service brake torque M_B.

[0052] Figure 3 shows a second embodiment of the drive system 14, to which the above and below statements apply accordingly with reference to the reference numerals. However, the second embodiment differs from the first embodiment in that the load braking device 16 is mechanically coupled to the input shaft 22 of the transmission 17. In this embodiment, the load braking device 16 is controlled by the control device 18 such that it is activated in a speed range n_b that is greater than the lower speed limit n_um and less than or equal to zero (i.e., less than the zero speed n_0).

[0053] Figure 4 shows a third embodiment of the drive system 14. The above statements with reference to the reference numerals apply accordingly to the third embodiment. The third embodiment of Figure 4 differs from the first embodiment of Figure 2 in that a speed detection unit 27 is also connected to the output shaft 20 of the electric motor 15, which detects the speed n of the output shaft 20 of the electric motor 15. The value for the current speed of the output shaft 20 is determined by the control device 18.

[0054] Figure 5 shows a fourth embodiment of the drive system 14, for which the above description also applies accordingly, based on the reference numerals. The fourth embodiment differs from the previous embodiments in that the speed detection unit 27 directly triggers the load brake device 16 when certain values ​​are exceeded or undershot. The centrifugal switch 26 directly triggers the activation of the service brake device 19 when the speed of the input shaft 22 of the transmission 17 exceeds a predetermined maximum speed n_max.

[0055] The person skilled in the art can combine the technical features of the individual embodiments one to four shown in Figures 2 to 5 as far as technically reasonable.

[0056] The features described with reference to the third and fourth embodiments can be combined accordingly with the second embodiment, in which the load braking device 16 is arranged on the transmission side.

[0057] Figure 6 shows a V / f characteristic curve for a typical frequency converter. In the V / f characteristic curve, there is a range 28 for frequencies above the rated frequency f_N, in which the applied voltage U is constant at the rated voltage U_N of the electric motor. In this range 28, the frequency converter operates in the so-called field weakening mode, in which the magnetic flux Φ decreases. In the further range 29, the magnetic flux Φ is at least essentially constant when the voltage U increases constantly. At low speeds, However, this operating mode leads to a drop in torque because the magnetic flux Φ collapses due to the lower motor currents.

[0058] In the previously described drive system 14, when the load is lifted in this area 30, the load braking device is activated so that on the one hand the attached load is secured by the load braking device 16, and on the other hand the electric motor works against the load torque M_L via the efficiency η of the overall mechanical system and the load braking torque M_S.

[0059] Figure 7 shows various load characteristics as a function of speed for the four quadrants, with the electric motor 15 in motor mode in the first quadrant 31, in generator mode in the second quadrant 32, in motor mode in the third quadrant 33 and in generator mode in the fourth quadrant 34.

[0060] The braking torque M_S of the load braking device 16 is greater than the nominal load torque M_L acting on the output shaft of the electric motor 15 and smaller than the drive torque M_A of the electric motor 15.

[0061] Within the speed range n_b, the electric motor 15 is in motor operation (in the third quadrant 33) even during a lowering movement and not in generator operation (in the fourth quadrant 34) as usual, since the braking torque M_S counteracts the drive torque M_A and the magnitude of the braking torque M_S is greater than the load torque M_L x η. At speeds n that are lower than the lower speed limit n_um, the load braking device 16 is switched off. The motor is now back in generator mode (in the fourth quadrant 34). During lifting movements where the speed n is greater than the upper speed limit n_om, the load braking device is also not activated.

[0062] The load braking device 16 makes the drive system 14 safer because, in the event that the frequency converter regulates unintentionally, for example because the necessary voltage increase fails during slow movements, the load braking device 16 prevents the tilting moment M_K of the electric motor 15 from being exceeded because, in this area, the load braking device 16 is already activated, thus preventing the load from sagging.

[0063] The lifting device 10 according to the invention has a drive system 14 with an electric motor 15 for applying a drive torque M_A with which the load can be raised and lowered, a load braking device 16 for applying a braking torque M_S with which the load can be held, a gear 17 and a control device 18 in communicative connection with the load braking device 16 and the electric motor 15, wherein the control device 18 is designed to control the load braking device 16 in such a way that, especially during slow lifting movements, the braking torque M_S of the load braking device 16 is greater than the load torque M_L of the load and less than the drive torque M_A of the electric motor 15. The load braking device 16 is activated in a predetermined speed range n_b, in which the electric motor 15 works against the braking torque M_S of the load braking device 16. Reference symbols: 10 Lifting device (load balancing device) 11 Traction device (chain) 12 Load handling device 13 Pocket wheel 14 Drive system 15 Electric motor (asynchronous motor) 16 Load braking device 17 Gearbox 18 Control device 19 Service braking device 20 Output shaft of the electric motor 21 Clutch device (slipping or hysteresis clutch) 22 Input shaft of the gearbox 23 Output shaft of the drive system 24 Motor side of the drive system 25 Operating side of the drive system 26 Centrifugal switch 27 Speed ​​detection unit 28 Area with U_N 29 Area with constant magnetic flux 30 Area with collapsing magnetic flux 31 First quadrant 32 Second quadrant 33 Third quadrant 34 Fourth quadrant M_A Drive torque M_B Service braking torque M_L Load torque M_K Tilting torque M_S Braking torque of the load braking device n speed n_b speed range n_0 zero speed n_om upper speed limit n_um lower speed limit n_max maximum speed T predetermined period n_s setpoint speed U_N rated voltage Φ magnetic flux η efficiency of the entire mechanical system f_N rated frequency

Claims

Claims:

1. Lifting device (10) with a drive system (14) and a traction means (11) connected to the drive system for lifting, lowering and holding a load attached thereto, wherein the drive system (14) has the following: an electric motor (15) for applying a drive torque (M_A) with which the load can be raised and lowered, a load braking device (16) for applying a braking torque (M_S) with which the load can be held, a gear (17), and a control device (18) in communicative connection with the load braking device (16) and the electric motor (15), wherein the control device (18) is designed to control the load braking device (16) in such a way that the braking torque (M_S) of the load braking device (16) is greater than the load torque (M_L) of the load and less than the drive torque (M_A) of the electric motor (15),when the electric motor (15) is in a predetermined speed range (n_b) that includes the zero speed (n_0).

2. Lifting device (10) according to claim 1, characterized in that the control device (18) is configured to activate the load braking device (16) when lowering the load if the speed (n) of the electric motor (15) exceeds a lower speed limit (n_um).

3. Lifting device (10) according to claim 1 or 2, characterized in that the control device (18) is configured to activate the load braking device (16) when lifting the load if the speed (n) of the electric motor (15) falls below an upper speed limit (n_om).

4. Lifting device (10) according to one of the preceding claims, characterized in that the electric motor (15) is designed as a three-phase asynchronous motor.

5. Lifting device (10) according to one of the preceding claims, characterized in that an output shaft (20) of the electric motor (4) is mechanically coupled to an input shaft (22) of the transmission (17) via a coupling device (21). 6.Lifting device (10) according to one of the preceding claims, characterized in that the load braking device (16) is arranged on the motor side, wherein the load braking device (16) is mechanically coupled to the output shaft (20) of the electric motor (15).

7. Lifting device (10) according to one of claims 1-5, characterized in that the load braking device (16) is arranged on the transmission side, wherein the load braking device (16) is mechanically coupled to the input shaft (22) of the transmission (17).

8. Lifting device (10) according to one of the preceding claims, characterized in that it further comprises a. A service brake device (19) arranged on the transmission side, wherein the service brake device (19) is configured to apply a service brake torque (M_B) to an input shaft (22) of the transmission (17), which is greater than the rated load torque (M_L) of the load.

9. The lifting device (10) according to claim 8, characterized in that the control device (18) is communicatively connected to the service brake device (19) and is configured to control the service brake device (19) such that it applies a service brake torque (M_B) when the absolute value of the rotational speed (n), in particular for a predetermined period of time (T), is at least substantially equal to the zero rotational speed (n_0) or the absolute value of the rotational speed (n) exceeds a maximum rotational speed limit (n_max). 10.Lifting device (10) according to one of the preceding claims, characterized in that the control device (18) is designed to regulate the braking torque (M_S) of the load braking device (16) as a function of the load torque (M_L).

11. Lifting device (10) according to one of the preceding claims, characterized in that the control device (18) is designed to adapt the speed range (n_b) defined by the lower and upper speed limits (n_um, n_om) to the load torque (M_L).

12. Lifting device (10) according to one of the preceding claims. Claims, characterized in that the braking torque (M_S) applied by the load braking device (16) can be changed by control signals received from the control device (18).

13. Lifting device (1) according to one of the preceding claims, characterized in that the control device (18) is configured to gradually reduce the braking torque (M_S) while the drive torque (M_A) is not equal to zero.

14. Lifting device (10) according to one of the preceding claims, characterized in that a centrifugal switch (26) is mechanically coupled on the operating side to the input shaft (22) of the transmission (17) and is communicatively connected to the control device (18) and / or the service braking device (19). 15.Control method for a lifting device (10), in particular the lifting device (10) according to one of the preceding claims, comprising: applying a braking torque (M_S) with the load braking device (16) which is greater than the nominal load torque (M_L) of the load and less than the drive torque (M_A) of the electric motor (15) when the electric motor (15) is in a predetermined speed range (n_b) which includes the zero speed (n_0).

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