JPH0920495A - Control device for hoist machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a hoist machine whereby proper operation can be performed not depending on the way of connection of phases R, S, T of supply power but always relating to an operating command, also to eliminate apprehension of causing an accident even in the case of fusing a contact. SOLUTION: A reversing/inverting relay 23 operated when connected in a positive phase is provided in a power cable, to supply a power circuit, leading to an electric motor 4 from the power cable 1, left as is when connected in a positive phase and to supply the circuit by inverting a phase when connected in a reverse phase, so that the motor can be driven even in the case of connecting by a reverse phase similarly to in the case of connecting by a positive phase, also to be able to perform only lift action at lift action time and only lower down action at lower down action time, in the case of fusing a contact of an electromagnetic switch 2 in a power supply side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric hoist, and more particularly to a hoist control device for preventing accidents caused by incorrect connection of phases of power supplies and electrode welding.

[0002]

2. Description of the Related Art A conventional hoisting machine control device will be described by taking an electric chain block as an example.
FIG. 6 is an exploded connection diagram of an electric chain block according to the related art, and FIG. 7 is an actual connection diagram of FIG.

In these drawings, an electric chain block includes a power supply cable 1 for supplying a power source, an electromagnetic switch 2 for controlling winding or winding down, a limit switch 3 for preventing overwinding or overwinding, and a drive source. A motor 4, a control device brake 5,
It is composed of a transformer 6 for lowering the voltage of the operation circuit, a reverse phase prevention relay 7 for stopping the operation when the connection of the power supply is in the reverse phase, and a push button switch 8 for issuing an operation command for the winding or winding operation. It

A winding contact 16 and a winding main circuit contact 17 are respectively provided in the three phases R, S and T of the power supply cable 1.
Is connected to the electric motor 4 so as to be able to supply electric power, and is also connected so as to be able to supply electric power via a contact 21 for winding down and a contact 22 for main winding down. The reverse phase prevention relay 7 has one end connected to each of the three phases of T, S, and R from the power feeding cable 1, and the other end connected to the capacitor 9, the resistor 10, the relay 11, and the secondary of the transformer 6. One end of the winding coil 15 and one end of the winding coil 20 through one end on the side, and a relay contact 12 connected to each end.
The other end of the winding coil 15 is the other end of the secondary side of the transformer, the winding button 13, and the winding operation circuit contact 14.
The other end of the winding coil 20 is connected to the other end of the secondary side of the transformer, the winding button 18, and the winding operation circuit contact 19. The brake 5 is connected between the S phase of the power feeding cable 1 and the U phase of the electric motor 4.

First, the case where the connection of the power supply in the above circuit is in the positive phase will be described.

When the power supply is in the positive phase, the reverse phase prevention relay 7 constituted by the relay 11 in which the capacitor 9 and the resistor 10 are combined operates to close the relay contact 12 to form an operation circuit.

When the hoisting operation is performed, the hoisting button 13 of the push-button switch 8 is pushed, and the hoisting operation circuit contact 14 of the limit switch 3 is pushed.
The winding coil 15 of the electromagnetic switch 2 is excited through the coil, the winding contact 16 is closed, and the limit switch 3
The electric power is supplied to the electric motor 4 through the hoisting main circuit contact 17, and at the same time the electric power is also supplied to the brake 5 to open the electric motor 4.
Rotates. At this time, the R, S, and T phases of the power supply are connected to the U, V, and W phases of the electric motor 4 to rotate in the normal direction. When performing the lowering operation, by pushing the lowering button 18 of the push button switch 8, the lowering coil 20 of the electromagnetic switch 2 is excited through the lowering operation circuit contact 19 of the limit switch 3, The lowering contact 21 is closed, where the R, S, T phases of the power supply are inverted to the T, S, R phases, and the electric power is supplied to the electric motor 4 via the lowering main circuit contact 22 of the limit switch 3. At the same time, the brake 5 is also supplied with power and released, and the electric motor 4 rotates. At this time, the inverted T, S, and R phases of the power supply are connected to the U, V, and W phases of the electric motor 4, respectively, and become opposite phases.
During the overwinding operation, the contact 14 for the hoisting operation circuit of the limit switch 3 and the contact 17 for the hoisting main circuit
Opens and the operation circuit and main circuit power are shut off and stopped. This is the same in the case of overwinding operation.

Next, the case where the connections of the power supplies are in reverse phase will be described.

When the supply power is in reverse phase, the terminal voltage of the relay 11 in the reverse phase prevention relay 7 is low and the relay 11 cannot operate, so the relay contact 12 cannot be closed, and therefore the operation circuit is constructed. Instead, the operation-disabled state is maintained. Therefore, as a countermeasure when the operation is not possible, the connection of the R / S / T phases of the power supply is in reverse phase.
To replace two of the three phases to connect to the normal phase,
The method of instructing work is specified in the nameplate and instruction manual.

[0010]

However, when the user overlooks the work instruction described on the nameplate, the instruction manual, etc., a malfunction occurs due to the connection of the power supply being out of phase. Nevertheless, if the product is mistakenly recognized as a product defect such as a defect because it cannot be operated and a complaint is made based on the false recognition, it is necessary to carry out an unnecessary complaint process simply due to a misconnection by the user.

The power supply is connected by connecting the cable pulled out from the product to a switchboard, etc., but if the connection location is far or at a high place, or if it is easy to enter due to crane equipment. When the user recognizes that the connection of the power supply is in the opposite phase, for example because it is a place where it is not possible to change the internal wiring of the push button switch at hand, anyway, if you press the winding push button In some cases, the machine is used in a winding operation, and when the push-down push button is pressed, the winding operation is performed. In such a case, as described above, the overwinding prevention device is invalidated, in other words, the overwinding prevention device does not function in a circuit manner, which leads to a dangerous state such as damage to parts or dropping of luggage.

Furthermore, if an abnormal situation occurs in which the electromagnetic switch, the relay or the limit switch is welded, an uncontrollable state is brought about, which not only causes inconvenience in operation, but also this inconvenience may lead to an accident. In particular, it is welding of the electromagnetic switch that is likely to occur in reality. This is because in the case of the contact of the relay, there is no make-up current because energization starts after the contact is closed, and only the energizing current and the breaking current are borne, and in the case of the contact of the limit switch, the operation is performed. This is because the operating circuit current is small because the main circuit contact operates only when the circuit contact cannot operate. On the other hand, in the case of an electromagnetic switch, turn it on,
Since all currents for energization and interruption are borne, the probability of occurrence of contact welding phenomenon increases.

The present invention has been made in view of the circumstances of the prior art as described above, and its object is to provide an R.S.
It is an object of the present invention to provide a hoisting machine control device that can always perform a correct operation with respect to an operation command regardless of the connection method of the T phase and that does not cause an accident even when the contacts are welded.

[0014]

In order to achieve the above object, the present invention provides a first power supply circuit for supplying power from a power supply to a motor in a positive phase, and a power supply from a power supply to a motor in reverse phase. A second power supply circuit, an instruction means for instructing a hoisting operation or a lowering operation, a first opening / closing means for connecting and disconnecting the first power supply circuit according to a hoisting side instruction output of the instruction means, and an instruction means The three-phase power supply phase sequence includes a second opening / closing means for connecting / disconnecting the second power supply circuit according to the unwinding side instruction output, and a limit switch for defining the highest position in the hoisting state and the lowest position in the hoisting state. In the control device of the hoisting machine that performs the hoisting operation or the hoisting operation by rotating the electric motor in the normal or reverse direction by switching
When the supply power source and the electric motor are connected in reverse phase, they are set inoperable, and the connection state between the first power supply circuit and the second power supply circuit is changed to reverse the phase of the supply power supply. It is characterized by having a relay that allows it.

In this case, the relay is the R.
It operates by changing the terminal voltage of the relay according to the S / T phase order, and when the electric motor is connected to the power supply in the positive phase, the ascending operation is possible only when the operating means instructs the ascending operation. The operation is limited to the maximum position set by the limit switch, and when the electric motor is connected in reverse phase to the power supply, the descending operation is possible only when the operating means instructs the descending operation. Limited to the lowest position set by the limit switch.

In the embodiment described later, the first power supply circuit corresponds to the connection circuit to the R / S / T phases including the connection circuits 33 and 34, the A side contact 26, and the winding main circuit contact 17, The power supply circuit of No. 2 is the connection circuits 35, 36 and the B-side contact 2
9. Corresponding to the connection circuit to the R / S / T phase including the unwinding main circuit contact 22, the instruction means corresponds to the push button switch 8, the first opening / closing means corresponds to the A side contact 26, The second opening / closing means corresponds to the B-side contact 29, the limit switch corresponds to 17 and 22, and the relay corresponds to the reverse rotation inversion relay 23.

[0017]

In a hoisting machine, for example, an electric chain block, the size and weight of the hoisting machine are small and it is easy to move and install the hoisting machine. Therefore, by taking in the R / S / T phases of the supply power source arbitrarily connected by the worker and greatly changing the terminal voltage of the relay combining the capacitor and the resistance between the positive phase and the negative phase, Detecting whether it is a positive phase or a negative phase, and even if it is a negative phase, by switching the hoisting circuit and the hoisting circuit at the time of the normal phase through the relay contact, the U
The R / S / T phases of the power supply are connected to the V / W phases, respectively, and the motor rotates in the normal direction.
-The T, S, and R phases of the power supply are connected to the W phase, and the motor rotates in reverse. As a result, it is possible to reliably operate the overwinding prevention device without changing the connection of the power supply, and to obtain high reliability with a simple structure.

Further, by constructing the relay as described above, even if an accident occurs in which the contacts of the electromagnetic switch are welded, if the relay is connected in the positive phase, the raising operation,
When connected in reverse phase, only the lowering operation can be performed, and the reversing operation does not occur, so that a serious accident such as chain breakage will not occur.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An electric chain block according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a developed connection diagram of a control circuit of an electric chain block according to an embodiment, FIG. 2 is a sectional view showing an internal structure of an electric chain block according to the embodiment, FIG. 3 is an external view thereof, and FIG. It is a flowchart which shows the operation procedure of the electric chain block which concerns on an Example.

In this embodiment, the relay contact 12 of the anti-phase preventing relay 7 in FIGS. 6 and 7 is replaced with an operation circuit relay contact 24 and a main circuit relay contact 27, and other parts are shown in FIGS. 7 and the mechanical structure is as shown in FIGS. 2 and 3, and the same reference numerals are given to the respective parts corresponding to the conventional example and the example, and detailed description will be given. The description is omitted.

The operation circuit relay contacts 24 are provided on the connection line 31 between the hoisting coil 15 and the hoisting operation circuit contact, and on the connection line 32 between the hoisting coil 19 and the hoisting coil 20, respectively. The main circuit relay contact 27 is a connection line 33 between the R phase of the winding contact 16 on the power supply side and the U phase of the electric motor 4, a connection line 34 between the T phase and the W phase, and a winding line on the power supply side. Connection line 3 between the R phase of the contact 21 for lowering and the W phase of the electric motor 4
5. Similarly, they are respectively provided on the connection lines 36 for connecting the T phase and the U phase. 2 and 3, reference numeral 41 is an upper hook for suspending the electric chain block, reference numeral 42 is a chain, and reference numeral 43 is provided at a lower end of the chain 42 and is a lower hook for suspending an object to be suspended. Reference numeral 44 is a cable having a push button switch 8 at the lower end.

In the embodiment thus constructed, when the connection of the power supply is in the positive phase, the following is done. That is, when the power supply is in positive phase, the capacitor 9 and the resistor 1
The operation circuit is configured by operating the reverse-phase inversion relay 23 configured by the relay 30 in which 0s are combined to close the operation circuit relay contact 24. At the same time, the main circuit relay controller point 27 is also closed and connected to the a side. In addition,
Here, the reverse phase inversion relay 23 includes a capacitor 9 and a resistor 1
It is configured to detect a positive phase or a negative phase by combining 0 and select the winding circuit or the winding circuit by the operation of the relay 23. However, the comparator discriminates between the positive phase and the negative phase, and the switching element Therefore, it is possible to use an electronic control circuit for switching the power supply.

When the hoisting operation is performed, the hoisting button 13 of the push button switch 8 is pressed (step 401) to cause electromagnetic contact via the hoisting operation circuit contact 14 of the limit switch 3 and the operation circuit relay contact 24. The A-side coil 25 of the switch 2 is excited (steps 402 and 403), and the A-side contact 26 is closed (step 4).
04), electric power is supplied to the electric motor 4 via the main circuit relay contact 27 and the hoisting main circuit contact 17 of the limit switch 3 (step 407), and at the same time, electric power is also supplied to the brake 5 to open the electric motor 4. (Step 40
8). At this time, the R, S, and T phases of the power supply are connected to the U, V, and W phases of the electric motor 4 to rotate in the normal direction. .

When the lowering operation is performed, the lowering button 18 of the push button switch 8 is pressed (step 411) to open the operating circuit relay contact 24 and the lowering operation circuit contact 19 of the limit switch 3. The B-side coil 28 of the electromagnetic switch 2 is excited through (steps 412 and 413), and the B-side contact 29 is closed (step 414). Here, the R / S / T phases of the power supply are reversed and T / S / The R phase is established, power is supplied to the electric motor 4 via the main circuit relay contact 27 and the lower switch main circuit contact 22 of the limit switch 3 (step 417), and at the same time, electric power is supplied to the brake 5 to open the electric motor 4. Rotate (step 418). At this time, the T / S of the power supply inverted
・ The R phase is connected to the U, V, and W phases of the motor 4, respectively, and reverses.

Therefore, during the overwinding operation, the winding operation circuit contact 14 and the winding main circuit contact 17 of the limit switch 3 are opened, the operation circuit and the main circuit are cut off and stopped, and the overwinding operation is performed. In the case, the contact 19 for the operating circuit of the limit switch 3 and the contact 22 for the unwinding main circuit are opened, and the power supply for the operating circuit and the main circuit is cut off and stopped.

Next, the case where the power supplies are in reverse phase will be described.

When the connection of the power supply is in reverse phase, the terminal voltage of the relay 30 in the reverse phase inversion relay 23 is low and the relay 30 cannot operate, so that the operation circuit relay contact 24,
The main circuit relay contact 27 remains connected to the contact on the right side in the drawing, and thus has a circuit configuration on the b contact side.

When the hoisting operation is performed, when the hoisting button 13 of the push button switch 8 is pressed (step 4
01), the relay contacts 14 for the operating circuit and the relay contacts 27 for the main circuit are not excited because they are in reverse phase (step 402,
405), via the hoisting operation circuit contact 14 of the limit switch 3, the operation circuit relay contact 2 of the relay 30
4, the B-side coil 28 of the electromagnetic switch 2 is excited and the B-side contact 29 is closed (step 40).
6) The reverse contact of the main circuit relay contact 27 of the relay 30 is reversed to the hoisting main circuit contact 17 of the limit switch 3 (step 407). Therefore, the order of the T / S / R phases of the power supply is U / V / W of the motor 4.
When connected to the phase, they are respectively inverted to the R, S, and T phases,
The electric motor 4 is normally rotated (step 408) and the winding operation is started.

When the lowering operation is performed, the lowering button 18 of the push button switch 8 is pressed (step 411).
The main circuit relay contact 27 is not excited (steps 412 and 415), and is inverted by the b contact of the operation circuit relay contact 24 of the relay 30 via the lowering operation circuit contact 19 of the limit switch 3 so that the main circuit relay contact 27 is not electromagnetically excited. The A-side coil 25 of the switch 2 is excited, the A-side contact is closed (step 416), and the main circuit relay contact 27 of the relay 30 is inverted by the b contact and connected to the unwinding main circuit contact of the limit switch 3. (Step 417). Therefore, the order of the T / S / R phases of the power supply is U / V / W of the motor 4.
The motor 4 is reversely connected (Step 4
18) Then, the lowering operation is started.

According to this structure, the limit switch 3 of the overwinding prevention device always responds to the winding or winding command regardless of whether the connection of the power supply is in the normal phase or in the reverse phase. The hoisting or hoisting control circuit is properly shut off, and it reliably functions as a safety device.

In this embodiment, it can function normally regardless of whether the phase when connected to the power supply circuit is positive or negative, but when the A-side contact 26 of the electromagnetic relay 2 is welded. The operation of is as shown in the flowchart of FIG.

First, when the winding operation is performed in the positive phase, the winding button 13 of the push button switch 8 is used.
When is pressed (step 501), if the phase is positive, the A-side coil 25 of the electromagnetic switch 2 is excited via the winding operation circuit contact 14 of the limit switch 3 and the operation circuit relay contact 24 (steps 502, 503). , The A-side contact 26 is closed (step 504), the hoisting main circuit contact 17 is closed (step 505), and the electric motor 4 is normally rotated to perform the hoisting operation. When the A-side contact 26 of the electromagnetic switch 2 is welded here, the winding operation is continued as it is. Then, the contact of the limit switch 3, in other words, the contact of the hoisting main circuit contact 17 is turned off, the forward rotation operation of the electric motor 4 is stopped (step 506), and this state is maintained. That is, the limit switch 3 moves up and the ascending operation is stopped until the limit switch 3 operates, and the state is maintained. After the A-side contact of the electromagnetic switch 2 is welded in step 504, even if the push button 8 is operated in the lowering direction (step 511) and the relay 30 is excited (step 513), the A-side contact of the electromagnetic switch 2 is also detected. Since 26 is welded, the B-side contact 29 of the electromagnetic switch 2 cannot operate due to the interlock with the A-side contact (step 514). As a result, the unwinding operation becomes impossible, and in any case, it goes up to the highest position and stops.

On the other hand, when performing the lowering operation, the lowering button 18 of the push button switch 8 is pressed (step 511), and if the phase is positive, the operation circuit relay contact 2
4, and the B side coil 28 of the electromagnetic switch 2 is excited via the contact 19 for the lowering operation circuit of the limit switch 3 (steps 512 and 513), but as described above, the A side contact 26 of the electromagnetic switch 2 is used. When welded, the B-side contact 29 of the electromagnetic switch 2 is in an interlocked state and cannot be turned on, and the winding operation cannot be performed as described above.

When the connection of the power supply is in the reverse phase, the terminal voltage of the relay 30 in the reverse phase inversion relay 23 is low as described above, and the relay 30 cannot operate. Therefore, the relay contact 24 for the operation circuit and the main circuit. The relay relay contact 27 remains connected to the contact on the right side of the drawing, and has a circuit configuration of b contact.

When the hoisting operation is performed, when the hoisting button 13 of the push button switch 8 is pressed (step 501), the operation circuit relay contact 14 and the main circuit relay contact 27 are not excited because they are in opposite phases (step 50).
2, 507), through the hoisting operation circuit contact 14 of the limit switch 3, it is inverted by the b contact of the operation circuit relay contact 24 of the relay 30, and the B side coil 28 of the electromagnetic switch 2 is excited. Since the side contact 26 is welded, it is turned on by interlocking with the A side contact 29.
The operation becomes impossible, and the winding operation cannot be performed.

When the lowering operation is performed, even if the lowering button 18 of the push button switch 8 is pressed (step 511), the operation circuit relay contact 14 and the main circuit relay contact 27 are not excited because they are in opposite phases. Step 5
12, 515), through the unwinding operation circuit contact 19 of the limit switch 3 and the B contact of the operation circuit relay contact 24 of the relay 30 to be reversed to the A of the electromagnetic switch 2.
The side coil 25 is excited and the A side contact is closed (step 4
16), the b contact of the main circuit relay contact 27 of the relay 30 is inverted and connected to the unwinding main circuit contact of the limit switch 3 (step 517). Therefore, the phase sequence of the T / S / R phases of the power supply is connected to the U / V / W phases of the electric motor 4 as they are, and the electric motor 4 is rotated in the reverse direction to perform the unwinding operation. Then, the lowering operation is continued, the contact of the limit switch 3, in other words, the contact of the lowering main circuit contact 22 is turned off, the reverse operation of the electric motor 4 is stopped (step 518), and this state is maintained. It That is, the limit switch 3 is lowered until it operates, the lowering operation is stopped, and the state is maintained. After the A-side contact of the electromagnetic switch 2 is welded in step 516, the push button 8 is operated in the upward direction (step 501).
Since the relay 30 is not excited (step 507) and the A-side contact 26 of the electromagnetic switch 2 is welded, the B-side contact 29 of the electromagnetic switch 2 cannot operate due to the interlock with the A-side contact 26 ( Step 508). As a result, the hoisting operation becomes impossible, and in any case, it goes down to the lowest position and stops.

Thus, the A-side contact 26 of the electromagnetic switch 2 is
When the welding is performed, if the ascending operation is performed at the time of welding, it rises until the limit switch 3 operates, and if the descending operation is performed, it descends until the limit switch 3 operates, and then stops, and then the welding occurs. The chain block cannot be driven until the electromagnetic switch 2 is replaced. That is, when the electromagnetic switch 2 is welded, it can be stopped without causing an accident.

In this embodiment, the electromagnetic switch A
Although the case where the side contact 26 is welded is taken as an example, the same operation is performed even when the B side contact 29 is welded so that no accident is caused.

As described above, according to the above-described embodiment, even when the power source and the electric chain block are connected in reverse phase, the operation is performed normally and an accident occurs even when the contacts of the electromagnetic switch are welded. It disappears.

[0041]

As is apparent from the above description, according to the present invention, the relay is set to be inoperable when the power supply and the electric motor are connected in reverse phase, and the first
Since the state of connection between the power supply circuit and the second power supply circuit is changed to reverse the phase of the power supply to be supplied, even if the power supply is connected to the reverse phase, the motor operates and is connected as in the normal phase. A malfunction does not occur due to the difference in phase. Furthermore, even if the contacts of the electromagnetic switch are welded, only the ascending or descending operation is performed to stop at the maximum ascending position or the descending position and restart is not possible, so it is possible to prevent accidents due to contact welding. it can.

[Brief description of drawings]

FIG. 1 is a developed connection diagram of a hoisting machine control circuit according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a structure of an electric chain block according to an embodiment.

FIG. 3 is an external view of an electric chain block according to an embodiment.

FIG. 4 is a flowchart showing an operation corresponding to the connection state of the power supply of the electric chain block according to the embodiment.

FIG. 5 is a flowchart showing an operation at the time of welding the contacts of the electromagnetic switch of the electric chain block according to the embodiment.

FIG. 6 is a developed connection diagram of a control circuit of an electric chain block according to a conventional technique.

FIG. 7 is an actual connection diagram of a control circuit of an electric chain block according to a conventional technique.

[Explanation of symbols]

 1 feeding cable 2 electromagnetic switch 3 limit switch 4 electric motor 8 push button switch 13 hoisting button 16 hoisting contact 17 hoisting main circuit contact 18 hoisting button 21 hoisting main circuit contact 22 hoisting main circuit contact 23 reverse phase inversion Relay 24 Operation circuit side relay contact 25 A side coil 26 A side contact 27 Main circuit relay contact 28 B side coil 29 B side contact

Claims (4)

[Claims] 1. A first power supply circuit for supplying power from a power supply to the motor in a positive phase, a second power supply circuit for supplying power from the power supply to the motor in a negative phase, and a hoisting operation or a hoisting operation. And a first opening / closing means for connecting / disconnecting the first power supply circuit in response to the winding-side instruction output of the instructing means, and a second power supply circuit in response to the winding-side instruction output of the instructing means. A second opening / closing means in contact with each other and a limit switch for defining the highest position in the hoisting state and the lowest position in the hoisting state are provided, and by switching the phase sequence of the three-phase power source, the electric motor is rotated in the forward or reverse direction to perform the hoisting operation or In the control device of the hoist that performs the unwinding operation,
When the supply power source and the electric motor are connected in reverse phase, they are set to be inoperable, and the connection state between the first power supply circuit and the second power supply circuit is changed to supply the phase of the power supply. A hoisting machine control device comprising a relay for reversing. 2. The relay comprises R, S, and
The hoisting machine control apparatus according to claim 1, wherein the relay terminal is operated by changing the terminal voltage of the relay according to the phase order of T. 3. The relay enables a raising operation only when a raising instruction is given by an operating means when the electric motor is connected to the supply power source in a positive phase, and the raising operation is the maximum set by the limit switch. The hoisting machine control device according to claim 1 or 2, wherein the hoisting machine is restricted to a position. 4. The relay enables a descending operation only when a descending instruction is given by the operating means when the electric motor is connected to the power supply in reverse phase, and the descending operation is a minimum setting set by the limit switch. The hoisting machine control device according to claim 1 or 2, wherein the hoisting machine is restricted to a position.