Control unit and method for operating a conveying means

Abstract

The invention relates to a method for operating a conveyor means, in particular a hoist, a crane, a continuous conveyor or the like, and to a control unit, the conveyor means comprising a drive unit (21) and a control unit (20) for controlling the drive unit, the drive unit comprising at least two drives (43, 44), the drives being controlled by means of a control device (22) of the control unit, a rotary encoder (25, 38) of the control unit being connected shafts (29, 42) of the drive unit of the conveyor means each allocated to the drives and registering a rotation of the shafts, a rotation angle signal and/or a rotational speed signal being transmitted to the control device by means of an encoder device (26, 39) of the corresponding rotary encoder in order to control the drives, the control device determining the corresponding rotational speed of the shafts and comparing it to a referential rotational speed, the control device controlling the drives depending on the comparison.

Claims

1. A method for operating a conveyor comprising a drive unit (21) and a control unit (20) for controlling the drive unit, the drive unit comprising at least two drives (43, 44), the at least two drives being controlled by a control device (22) of the control unit, a rotary encoder (25, 35, 38, 49) of the control unit being connected to shafts (29, 42) of the drive unit of the conveyor each allocated to the at least two drives and registering a rotation of the shafts, a rotation angle signal or a rotational speed signal being transmitted to the control device by an encoder device (26, 39) of the corresponding rotary encoder in order to control the drives, the method including the step of determining via the control device a corresponding rotational speed of the shafts and comparing the rotational speed of the shafts to a referential rotational speed, and controlling the drives via the control device depending on the comparison; and wherein the control device (22) defines or selects a referential acceleration according to a measured acceleration of one of the shafts.

2. The method according to claim 1, wherein the control device (22) determines the referential rotational speed according to a rotation angle signal or a rotational speed signal of one of the rotatory encoders (25, 42), the control device regulating each drive depending on the referential rotational speed.

3. The method according to claim 1, wherein the control device (22) determines the corresponding acceleration of the shafts (29, 42) and compares it to a referential acceleration, the control device regulating each drive (43, 44) depending on the referential acceleration.

4. The method according to claim 3, wherein the control device (22) registers a load signal from load sensors (36, 37) of a sensor device (23) of the control unit (20) allocated to the drives (43, 44) and compares it to a referential load, the control device regulating each drive depending on the referential load.

5. The method according to claim 4, wherein a range parameter of a rotational speed, an acceleration or a load is stored in the control device (22), the referential rotational speed, the referential acceleration or the referential load each being limited by the range parameter.

6. The method according to claim 4, wherein the load signals from the load sensor are registered by the rotary encoder (25, 35, 38, 49), the rotary encoders each determining a load-dependent variable depending on the rotation angle signal or the rotational speed signal and transmitting it to the control device (22) in order to control the drives (43, 44).

7. The method according to claim 4, wherein the control device (22) limits a rotational speed of the drives (43, 44) or switches off the drives when exceeding a load.

8. The method according to claim 4, wherein load signals are registered for a working point, a rope load or a winding load by a plurality of load sensors (36, 37) allocated to a drive (43, 44) each.

9. The method according to claim 1, wherein a load signal is registered by load sensors (36, 37), which are allocated to the drives (43, 44), by a safety element (27, 40) of the corresponding rotary encoder (25, 35, 38, 49), the safety element determining a load-dependent maximal threshold rotational speed depending on the rotation angle signal or the rotational speed signal and the load signal and transmitting it to the control device (22) in order to control the drive.

10. The method according to claim 9, wherein the safety element (27, 40) determines a function of the threshold rotational speed from the rotation angle signal or the rotational speed signal and the load signal.

11. The method according to claim 9, wherein that the safety element (27, 40) corrects a load signal of a load sensor (36, 37) while taking an acceleration of a working load at the conveyor into account.

12. The method according to claim 9, wherein the safety element (27, 40) determines a lifting, a lowering, an overload, a slack rope or an empty running as an operating type of the drive (43, 44) depending on the rotation angle signal or the rotational speed signal or the load signal and transmits it to the control device (22).

13. The method according to claim 9, wherein a switch signal of a terminal switch of the sensor device is registered by the rotary encoder (25, 35, 38, 49), the rotary encoder determining a relative position of a working load on the conveyor depending at the switch signal, the safety element (27, 40) taking the switch signal into account when determining the load-dependent threshold rotary speed.

14. The method according to claim 9, wherein the load signal is registered by a counter (28, 41) of the rotary encoder (25, 35, 48, 49), the counter storing the rotation angle signals or the rotational speed signals and the load signals over an operational period, determining a load-dependent damage value and transmitting it to the control device (22) in order to control the drive (43, 44).

15. The method according to claim 9, wherein the load signal is registered by an evaluation device of the rotary encoder (25, 35, 38, 49), the evaluation device determining a weight of a working load at the conveyor from the load signal and transmitting it to the control device (22).

16. A control unit (20) for a conveyor comprising a control device (22) and at least two rotary encoders (25, 35, 38, 49), the rotary encoder being connectable to shafts (29, 42) of a conveyor allocated to a drive (43, 44) each of a drive unit (21) in order to register a rotation of the corresponding shaft, the rotary encoder comprising an encoder device (26, 39) for outputting a rotation angle signal or a rotational speed signal to the control device (22) in order to control the drive unit, wherein the corresponding rotational speed of the shaft is determinable and comparable to a referential rotational speed by the control device, the drives being controllable by the control device depending on the comparison; wherein the control device (22) defines or selects a referential acceleration according to a measured acceleration of one of the shafts.

17. The control unit according to claim 16, wherein one of the rotary encoders (25, 35, 38, 49) comprises the control device (22).

18. The control unit according to claim 16, wherein the rotary encoder (25, 35, 38, 49) is an incremental encoder or an absolute encoder.

19. The control unit according to claim 16, wherein the control unit (20) comprises four or more rotary encoders (25, 35, 38, 49).

20. A conveyor comprising the control unit (20) according to claim 16 and a drive unit (21) having at least two electric motors (34, 48), a transmission and two rope drums (30, 45).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the invention is described in more detail by making reference to the attached drawings.

(2) FIG. 1 is a schematic illustration of a configuration of a control unit according to the state of the art;

(3) FIG. 2 is a schematic illustration of a configuration of a control unit;

(4) FIG. 3 is a simplified illustration of drive unit.

DETAILED DESCRIPTION

(5) FIG. 1 shows a control unit 10 according to the state of the art in conjunction with a drive unit 11 which has a drive not illustrated in the drawing. Control unit 10 comprises a control device 12, a sensor device 13 having a load sensor (not illustrated), a programming device 14 and a rotary encoder 15. Further rotary encoders 15, which are connected to drives of drive unit 11, can be connected to control device 12. Control device 12 comprises a processing element 16 which can receive a load signal of a load sensor from sensor device 13. Furthermore, processing element 16 can receive a rotation angle signal and/or a rotational speed signal of an encoder device 17 of rotary encoder 15. Rotary encoder 15 is coupled to drive unit 11 via a shaft 18 in this instance, drive unit 11 being configured to comprise a rope drum (not illustrated) and an electric motor (not illustrated) and a transmission (not illustrated). Control unit 10 and drive unit 11 are part of a hoist or a crane, neither of which is illustrated in this instance.

(6) Processing element 16 calculates a load-dependent variable, such as a maximal threshold rotational speed, from the load signals of sensor device 13 and the rotation angle signals and/or the rotational speed signals of rotary encoders 15, transmits control signals based on the variable to control unit 11 and receives status signals from drive unit 11. Control device 12 is programmable by means of programming device 14, which can be a computer (not further illustrated). Furthermore, control unit 10 comprises a counter 19, which can add load signals of sensor device 13 present in processing device 16 over an operating period and can thus determine a sum load. From this, a damage value is yielded which can be transmitted back to processing device 16 from counter 19, for example in the form of a switch-off signal.

(7) FIG. 2 shows a control unit 20 in conjunction with a drive unit 21 in a simplified illustration. Control unit 20 comprises a control device 22, a sensor device 23 having load sensors 36, 37, a programming device 24 and a rotary encoder 25 and 38. Rotary encoder 25 and 38 themselves each comprise encoder devices 26 and 39, respectively, safety elements 27 and 40, respectively, and counters 28 and 41, respectively, and are coupled with drives 43 and 44 of drive unit 21 via shafts 29 and 42, respectively.

(8) When operating drive unit 21 or drives 43 and 44, rotary encoder 25 coupled with drive 43 and rotary encoder 38 coupled with drive 44 detect a corresponding rotation angle signal and/or a rotational speed signal via corresponding encoder device 26 and 39 and transmit these to control device 22. Furthermore, rotary encoder 25 and 38 each receive a load signal from sensor device 22 or respective load sensor 36 and 37, safety device 27 and 40 each determining a load-dependent variable, for example a maximal threshold rotational speed for each drive 43 and 44, from the respective rotation angle signal and/or the respective rotational speed signal and the respective load signal, the maximal threshold rotational speeds each being transmitted to control device 22 in order to control drive unit 21 or drives 43 and 44.

(9) Furthermore, respective counter 28 and 41 each add up the corresponding load signals within an operating period of drive 43 and 44 and transmit a damage value to control device 22. When reaching a certain damage value, control device 22 can switch off the drive unit, for example. Control device 22 is programmable via programming device 24. Control device 22 can also directly receive and further process load signals from sensor device 23. Control device 22 receives status signals from drive unit 21 or drives 43 and 44 and forwards these to the corresponding rotary encoders 25 and 38. Status signals concern an operating type of drives 43 and 44, such as lifting or lowering a bearing load or a slack rope.

(10) The rotation angle signals and/or the rotational speed signals transmitted by rotary encoders 25 and 38 to control device 22 are further processed by the control device such that a rotational speed of corresponding drive 43 and 44 is determined for each drive 43 and 44. Control device 22 compares the corresponding rotational speed to a referential rotational speed, which can be stored in control device 22 in the form of a range parameter. Furthermore, it can also be intended to define one of the two rotational speeds from control device 22 as the referential rotational speed. It is essential that control device 22 controls drives 43 and 44 depending on a comparison of the corresponding rotational speeds to the referential rotational speed. If, for example, drives 43 and 44 are regulated using control device 22 resulting from rotational speeds of drives 43 and 44 yielded from the corresponding rotation angle signals and/or rotational speed signals of rotary encoder 25 and 38, control device 22 can define the rotational speed allocated to drive 43 as a referential rotational speed. The rotational speeds are now compared to the referential rotational speed, the rotational speed and the referential rotational speed consequently being identical in drive 43. The rotational speed of drive 44 is regulated according to referential rotational speed. Furthermore, it can also be intended for the control device to undertake a supplementary regulation according to an acceleration and/or a load.

(11) FIG. 3 is a schematic illustration of drive unit 21 having rotary encoders 25 and 38. Rotary encoders 25 and 38 are coupled with rope drums 30 and 45, respectively, via ropes 31 and 46, respectively, and via shafts 29 and 42, respectively, meaning that rotary encoders 25 and 38 can each detect a rotation angle and/or a rotational speed of rope drums 30 and 45, respectively. Rope drums 30 and 45 each possess a rope break 32 and 47, respectively, and are each coupled to electric motors 34 and 48, respectively, which drive rope drums 40 and 45 via a transmission 33. Optionally, another rotary encoder 35 can be coupled to electric motor 34 and another rotary encoder 49 can be coupled to electric motor 48, with the result that a rotational speed of electric motor 34 and 48 is detectable by means rotary encoders 35 and 49. Rotary encoders 35 and 49 can then be essentially realized like rotary encoders 25 and 38 and be a component of control unit 20.