JP2668202B2 - Control method of hoist having torque converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for a hoist that transmits the rotation of a prime mover to a hoist drum by a torque converter, and more particularly to a control method for a hoist capable of quickly lowering a light suspended load.

[0002]

2. Description of the Related Art Hoists using a torque converter are:
It is difficult to drop heavy and light suspended loads as quickly as possible. Heavy loads can be dropped quickly, but light loads are difficult to drop quickly. A heavy load can be lowered by its own weight by driving the hoisting drum in the hoisting direction of the load by the engine and the torque converter, but a light load cannot be lowered in this state. For heavy loads, the rate of descent can be controlled by adjusting the transfer torque of the torque converter. When the transmission torque of the torque converter is increased, the lifting force of the suspended load increases, and the descending speed of the suspended load decreases. Conversely, when the transmission torque of the torque converter is reduced, the descent speed of the suspended load increases.

Light suspended loads cannot be lowered quickly in this state. This is because even if the transmission torque of the torque converter is adjusted to be small, the suspended load does not drop by its own weight. In other words, the transmission torque of the torque converter cannot be adjusted to be smaller than the weight of the suspended load.

In order to quickly drop a light load, the present inventor has developed a method of reversing the hoist drum when lowering a light load. The hoist used in this method is shown in FIG.
Shown in This hoisting machine includes a prime mover 1, a hoisting drum 4 connected to an output side of the prime mover 1 via a torque converter 2 and a forward / reverse gear 3, and a torque converter 2 to control the hoisting drum 4. Control means S for controlling rotation.

The control means S includes a command means 6 for issuing a command for raising, lowering and stopping the suspended load, a torque controller 7 for adjusting the transfer torque of the torque converter 2 by the command of the command means 6, and a command means. A forward / reverse controller 8 that switches the forward / reverse gear 3 in response to the command 6 and a brake controller 11 that rotates the hoisting drum 4 at a set speed.

The torque controller 7 controls the transmission torque of the torque converter 2 corresponding to the ascending / descending position 12 of the command means 6. The forward / reverse controller 8 switches the forward / reverse gear 3 in the reverse direction when the command means 6 is switched to the forced lowering position 14, and switches the forward / reverse gear 3 in the forward direction when the command means 6 is in the upward / downward position 12.

The hoist shown in FIG. 1 has a command means 6 shown in FIG.
As the operation lever 5 is moved to the raised position,
The transmission torque of the torque converter 2 is increased to raise the suspended load at a high speed. Conversely, when the operating lever 5 is moved to a lower position below the center, the torque converter 2
Of the hoisting drum 4 becomes larger than the hoisting torque of the hoisting drum 4, and the heavy hoisting load drops due to its own weight.

When the suspended load cannot be quickly lowered due to its own weight even if the transmitted load of the torque converter 2 is adjusted to be weak because the suspended load is light, the command means 6 is switched to the forced lowering position 14. When the command means 6 is switched to the forced lowering position 14, this is detected by the forward / reverse controller 8, and the forward / reverse controller 8 switches the forward / reverse gear 3 in the reverse direction to forcibly lower the suspended load.

When the forward / reverse gear 3 is in the forward rotation position, when the transmission torque of the torque converter 2 increases, the hoisting drum 4 rotates in the direction in which the suspended load is hoisted. When the transmission torque of the torque converter 2 is increased, the torque for forcibly lowering the suspended load is increased, and even a light suspended load is forcibly and rapidly lowered. For this reason, the hoisting machine that lowers the suspended load by this method can forcibly drop the light suspended load.

[0010]

However, this method has a drawback that the descending speed changes depending on the weight of the suspended load, and it is difficult to descend the suspended loads having different weights at the optimum speed. This is because the descent speed of the suspended load changes due to the weight of the suspended load even when the hoisting drum 4 is reversed by the torque converter 2.

Further, this method has a disadvantage that a time delay until a light suspended load is accelerated to a constant descending speed is large.
In order to rapidly accelerate a stationary light suspended load and lower it at a constant speed, it is necessary to increase the transmission torque of the torque converter 2. However, torque converter 2
When the transmission torque of the motor is increased, the descending speed after acceleration is also increased. For this reason, if the transmission torque of the torque converter 2 is increased in order to shorten the acceleration time, the lifting speed of the suspended load also increases, and it becomes impossible to descend at the set speed.

Further, Japanese Patent Publication No. 4-5638 discloses that
The control device shown in FIG. 5 is described. The device of this figure lowers the suspended load as follows. The engine 1A is brought into an idling state. The forward / reverse gear 3 is switched, and the hoisting drum 4 is slowly reversed by the idling engine 1A and the torque converter 2. Since the hoisting drum 4 is reversed, the suspended load descends. As the descending speed of the suspended load increases, the engine brake in the idling state increases, and the descending speed of the suspended load is braked by the engine brake. In order to prevent the descent rate of the suspended load from becoming too fast and running away, the rotation speed of the torque converter 2 is detected and the brake 10 connected to the output shaft of the torque converter 2 is controlled. Therefore, it is possible to prevent the suspended load from running away and dropping.

In the method of lowering the suspended load by the apparatus shown in this figure, the hoisting drum 4 is reversed, so that the light suspended load can be lowered. However, in this method, since the descending speed of the suspended load is braked by the engine brake, the descending speed changes depending on the weight of the suspended load. The lowering speed of light loads is slower and the lowering speed of heavy loads is faster. Further, also in this method, since the suspended load cannot be rapidly accelerated in the descending direction by the torque converter 2 to have a constant speed, there is a time delay until the suspended load has a constant descending speed. The descending load is slowly accelerated to a constant descending speed.

The present invention has been developed with the object of eliminating these drawbacks.
It is an object of the present invention to provide a control method of a hoist having a torque converter capable of rapidly accelerating a light suspended load without being affected by the weight of the suspended load and smoothly descending at a set ideal speed.

[0015]

According to the method for controlling a hoist having a torque converter of the present invention, a suspended load is lowered as described below to achieve the above-mentioned object. In the method of the present invention, the rotation of the prime mover 1 is transmitted to the hoist drum 4 via the torque converter 2 and the forward / reverse gear 3. When lowering a heavy suspended load, the hoisting drum 4 is driven in the lifting direction of the suspended load. When lowering a light suspended load, the forward / reverse gear 3 is switched and the hoisting drum 4 drives the suspended load in the descending direction.

The method of the present invention is a further improvement of this method. When lowering a light suspended load, the transfer torque of the torque converter 2 is adjusted to control the lowering speed. As the descending speed of the suspended load is set higher, the transmission torque of the torque converter 2 is adjusted to be larger. Further, the descent speed of the suspended load is detected by the sensor 9, and the sensor 9 controls the brake 10 that controls the rotation of the hoisting drum 4. The brake 10 controls the hoisted drum 4 when the suspended load becomes faster than the set speed. Brake the rotation of Furthermore, the method of the present invention adjusts the transmission torque of the torque converter 2 so as to reach the set speed while the brake 10 controls the rotation of the hoisting drum 4 in order to accelerate the suspended load quickly. I have. That is, the method of the present invention forcibly reverses the hoisting drum 4 with the brake 10 applied, and lowers the suspended load at the set speed. With the brake 10 released, the hoisting drum 4
Is not adjusted by adjusting the torque for reverse rotation of the load. In the state where the brake 10 is released, the descending speed of the suspended load is higher than the set speed,
The transmission torque of the torque converter 2 is adjusted. A suspended load whose descending speed is too fast is braked by the brake 10 and descends at a set speed.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A hoisting machine control method according to the present invention is designed such that when a light load is lowered, the hoisting drum 4 is rotated in the reverse direction, and the hoisting drum 4 is braked by a brake 10 to obtain a torque. The converter 2 forcibly reverses the hoisting drum 4, and as the descent speed of the suspended load is increased,
The transmission torque of the torque converter 2 is gradually increased, and the rotation of the hoisting drum 4 is braked by the brake 10 so that the suspended load reaches the set speed.

In the control method of the present invention, for example, the command means 6 shown in FIG. The commanding means 6 shown in this figure has a suspended position 13 at the center in the upper and lower directions, a raised position from the center and a lowered position from the center. As the operation lever 5 as the command means 6 is moved upward, the lifting speed of the suspended load is increased, and as it is moved downward, the descent speed is increased. When the operating lever 5 is moved to the right at the upper and lower centers, the forward / reverse gear 3 is switched, and the hoisting drum 4 is rotated in the reverse direction. When the operation lever 5 moved to the right is lowered, the transmission torque of the torque converter 2 is gradually increased, and the speed at which the operation lever 5 is forcibly lowered is increased.

When the hoisting drum 4 is reversed to forcibly drop a light load, the descent speed of the load is detected and the rotation of the hoisting drum 4 is braked by the brake 10. According to the method of the present invention, the torque converter 2 forcibly reverses the hoisting drum 4 while the brake 10 brakes the rotation of the hoisting drum 4. Therefore, even if the suspended load is light, the torque is rapidly accelerated to a constant value. Can descend at speed. Further, the brake 10 is mounted on the hoisting drum 4
In the state where the rotation is controlled, the light suspended load is forcibly lowered, so that the suspended load can be lowered at the set speed regardless of the weight of the suspended load.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments shown below exemplify a control method of a hoisting machine having a torque converter for embodying the technical idea of the present invention, and the present invention specifies the control method in the following states. do not do.

Further, in this specification, in order to facilitate understanding of the claims, the numbers corresponding to the members shown in the examples are referred to as "claims" and "embodiments". "And" Means for solving the problem ". However, the members described in the claims are not limited to the members of the embodiments.

The method of controlling the hoisting machine having the torque converter of the present invention can be realized by using the hoisting machine shown in FIG. The hoisting machine shown in this figure is a prime mover 1 which is an internal combustion engine operated at a constant rotation speed, and a hoisting machine connected to the output side of the prime mover 1 via a torque converter 2 and a forward / reverse gear 3. A drum 4 and control means S for controlling the transmission torque of the torque converter 2 and the braking force of the brake 10 to rotate the hoisting drum 4 at a set speed are provided.

The control means S comprises a command means 6 having an operation lever 5 for issuing a command for raising, lowering and stopping the suspended load.
A torque controller 7 for adjusting the transmission torque of the torque converter 2 by a command from the operating lever 5, a forward / reverse controller 8 for switching the rotation of the forward / reverse gear 3 by a command from the operating lever 5, Alternatively, the hanging speed sensor 9 that indirectly detects the load is stopped when the forward / reverse controller 8 switches the forward / reverse gear 3, and
The brake controller 11 of the brake 10 that controls the descent rate of the suspended load is provided.

The operating lever 5 of the command means 6 is thereby used to raise and lower a suspended load of any load at a desired speed and to stop it at a predetermined position.
Therefore, as shown in FIG. 2, there is a stop position 13 in the middle of the ascending / descending position 12, and the stop position 13 in the middle of the ascending / descending position 12 is movable in the lateral direction intersecting with the stopping position 13.
Moreover, it has a forced lowering position 14 that can move further in the descending direction from the position that has moved in the lateral direction, and is movably supported. The operation lever 5 increases the lifting or lowering speed of the suspended load as the distance from the stop position 13 increases.

The torque controller 7 adjusts the transmission torque of the torque converter 2. When the operating lever 5 is in the ascending / descending position 12, the torque controller 7
The transmission torque of the torque converter 2 is increased as the operation lever 5 is moved upward in FIG. For heavy loads, move the operating lever 5 upwards to move the torque converter 2
This is because when the transmission torque is increased, the speed increases quickly, and when the transmission torque is decreased, the speed decreases.

When the operating lever 5 is switched to the forced lowering position 14 in order to forcibly lower the light suspended load, the torque controller 7 transmits the transmission torque of the torque converter 2 as the operating lever 5 is positioned lower. To increase. This is because, in order to quickly lower a light suspended load, it is necessary to increase the transmission torque of the torque converter 2 and forcibly reverse the hoisting drum 4. When the operation lever 5 is located at the forced lowering position 14, the torque controller 7 adjusts the transmission torque of the torque converter 2 so that the suspended load can be lowered at a set speed while the hoisting drum 4 is being braked. . In other words, when the brake 10 is released, the torque controller 7 sets the transmission torque of the torque converter 2 so that the suspended load descends faster than the set speed.

The torque controller 7 is controlled by the command means 6 to generate a rotation pulse circuit 15 for generating a pulse corresponding to the output signal of the descending speed sensor 9 and a pulse number corresponding to the command from the command means 6. Command pulse circuit 17, rotation pulse circuit 15, and command pulse circuit 17
A counter 16 for counting the number of output pulses from the counter 16 and an adjusting means 18 for controlling the transmission torque of the torque converter 2 corresponding to the output of the counter 16 are provided.

The sensor 9 is directly connected to the output shaft of the torque converter 2 or is connected to the rotary shaft of the hoisting drum 4 (not shown) to detect the descending speed of the suspended load.
Further, although not shown, the descending speed sensor 9 can also detect the moving speed of the hoisting wire wound on the hoisting drum 4. As the sensor for detecting the rotation of the torque converter 2 and the hoisting drum 4, a sensor capable of detecting the rotation speed and direction, for example, a rotary encoder or a resolver can be used.

The rotation pulse circuit 15 has two outputs A and B.
Is output. The output states of the outputs A and B are reversed when the operation lever 5 is at the ascending / descending position 12 and at the forced descending position 14.

When the operating lever 5 is at the ascending / descending position 12, when the suspended load is raised, the output A of the rotation pulse circuit 15 outputs a number of pulses proportional to the rotation angle. , Output B outputs a number of pulses proportional to the rotation angle.

When the operating lever 5 is in the forced lowering position 14, when the suspended load is lowered, the output A of the rotation pulse circuit 15 outputs the number of pulses corresponding to the rotation angle.

The descending speed sensor 9 and the rotation pulse circuit 1
For example, 5 is configured to generate one pulse every time the output shaft of the torque converter 2 to the hoisting drum 4 rotates by a certain angle. That is, when the rotating shaft of the hoist drum 4 rotates forward or backward by a predetermined fixed angle, the outputs A and B are output.
One pulse is output to one of them.

The counter 16 subtracts the pulse number of the output A from the count value and adds the pulse number of the output B to the count value. Therefore, the count value of the counter 16 decreases when the suspended load is raised and increases when the suspended load is lowered when the operation lever 5 is at the raising / lowering position 12. When the operating lever 5 is in the forced lowering position 14, on the contrary, when the suspended load is lowered, the count value is decreased.

The operating lever 5 of the command means 6 for moving the suspended load up and down is connected to the command pulse circuit 17. The command pulse circuit 17 sends many pulses per unit time to the counter 16 as the operation lever 5 moves away from the stop position 13 to adjust the transmission torque of the torque converter 2. When the operation lever 5 is tilted to the raised position, the command pulse circuit 17 outputs a pulse having a constant cycle to the output C, and when the operation lever 5 is tilted to the lowered position, the command pulse circuit 17 outputs a pulse having a constant cycle to the output D and the operation lever 5. Is tilted to the forced descent position 14, the output C gives a pulse, and when the operating lever 5 is at the neutral stop position 13, the command pulse circuit 17 does not give a pulse to the outputs C and D.

The frequency of the pulse output from the command pulse circuit 17 is such that when the operating lever 5 is in the ascending / descending position 12, the higher the operating lever 5 is in FIG. When the operation lever 5 is in the forced lowering position 14, the lower the operation lever 5 is, the more pulses are sent to the counter 16 per unit time. When the operation lever 5 is at the ascending / descending position 12, the transmission torque of the torque converter 2 is increased as the operation lever 5 is moved upward, and the load is lifted with a strong force. When the operating lever 5 is in the forced lowering position 14, the lower the operating lever 5 is, the larger the transmission torque of the torque converter 2 is. This is because the torque for reversing the hoisting drum 4 is increased and the light suspended load is quickly lowered.

The counter 16 adds the number of pulses output from the output C of the command pulse circuit 17 to the count value and subtracts the number of pulses output from the output D of the command pulse circuit 17 from the count value.

The adjusting means 18 includes a D / A converter 18A for converting the count value of the counter 16 into an analog quantity,
Command solenoid valve 1 that operates in proportion to the output of A converter 18A
9, the larger the count value of the counter 16 is,
The command solenoid valve 19 sends a liquid having a high command pressure to the torque converter 2.

The torque converter 2 shown in FIG. 3 comprises a clutch 20 and a torque converter body 21. In the clutch 20, when a high-pressure fluid is sent from the command solenoid valve 19 to the clutch pressure adjusting cylinder 22, the clutch pressing plate 23 is pressed by this pressure, which causes the clutch pressing plate 23 to press the multi-plate clutch 24. Torque proportional to the pushing force is transmitted to the output shaft 25 of the clutch 20. The output shaft 25 of the clutch 20 rotates an impeller 26 of the torque converter main body 21, and the rotation of the impeller 26 is rotated by a turbine 27 of the torque converter main body 21 via hydraulic oil.
Rotate the axis.

In the torque converter 2 of this figure, when a fluid having a pressure higher than that of the clutch pressure adjusting cylinder 22 is pressed by the command solenoid valve 19, the transmission torque of the clutch 20 increases, and the output shaft of the torque converter 2 increases. The rotational torque of the motor increases.

Therefore, in the hoisting machine shown in FIG. 1, as the count value of the counter 16 increases, the transmission torque of the torque converter 2 increases, and the lifting load or the forced lowering force becomes stronger.

The forward / reverse controller 8 detects that the operating lever 5 has been switched between the ascending / descending position 12 and the forced descending position 14, and switches the forward / reverse gear 3. When the operating lever 5 is at the ascending / descending position 12, the forward / reverse controller 8 sets the forward / reverse gear 3 to the forward rotation position, and when the operating lever 5 is at the forcible descending position 14, switches the forward / reverse gear 3 to the reverse position. The forward / reverse controller 8 can use any member that can detect whether the operating lever 5 is in the ascending / descending position 12 or the forcible descending position 14, for example, a limit switch.

The forward / reverse gear 3 is connected to the output side of the torque converter 2 and switches the rotation direction of the hoisting drum 4 by using the prime mover 1 whose rotation direction cannot be changed.

When the forward / reverse controller 8 switches the forward / reverse gear 3, it is preferable to stop the suspended load with the brake 10. Therefore, the hoisting machine of FIG. 1 is provided with the brake 10 between the output side of the torque converter 2 and the forward / reverse gear 3. The brake 10 provided here can be incorporated in the casing of the torque converter 2 together with the forward / reverse gear 3. The rotation of the brake 10 is controlled by the brake controller 11. The brake 10 is a forward / reverse gear 3
It is connected to the rotary shaft of the hoisting drum 4 via a gear 28. Therefore, when the brake 10 brakes the rotation of the output shaft of the torque converter 2, the rotation of the hoist drum 4 is braked.

When the operating lever 5 is moved from the ascending / descending position 12 to the forcibly descending position 14, the brake controller 11 stops the suspended load by operating the brake 10 and moves the operating lever 5 along the forcibly descending position 14. Then, the brake 10 is released and the forced descent position 14
When the operation lever 5 is moved toward the ascending / descending position 12, the brake 10 is operated to stop the suspended load. The hoisting machine in which the rotation of the hoisting drum 4 is stopped by the brake 10 and the forward / reverse gear 3 is switched has a feature that the forward / reverse gear 3 can be smoothly switched with less impact.

The brake controller 11 brakes the rotation of the hoisting drum 4 so as to lower the suspended load at a speed set by the operation lever 5 in the forced lowering position 14. The brake controller 11 controls the braking force of the hoisting drum 4 by comparing the set speed input from the operation lever 5 at the forced lowering position 14 with the descent speed of the suspended load input from the sensor 9. According to the signal input from the descending speed sensor 9, as the descending speed of the suspended load is faster than the set speed of the operating lever 5, the braking force of the hoisting drum 4 is increased and the rotation speed of the hoisting drum 4 is decreased. . On the contrary, according to the signal input from the descending speed sensor 9, the slower the descending speed of the suspended load is than the set speed of the operation lever 5, the weaker the braking force of the hoisting drum 4 is, and the rotation speed of the hoisting drum 4 is decreased. Make it faster. When the operating lever 5 is at the ascending / descending position 12, the brake 10 does not brake the rotation of the hoisting drum 4 except for the stop position 13.

As the brake 10 that is controlled by the brake controller 11 to brake the rotation of the hoisting drum 4, a wet brake built in the casing of the torque converter 2 can be used. However, the brake may be provided on the rotating shaft of the hoist drum 4 as shown by the chain line in FIG. A disc brake is most suitable for the brake 10 provided on the rotating shaft of the hoisting drum 4. Further, the brake can be fixed to the output shaft of the forward / reverse gear or can be further fixed to the rotating shaft of the gear. As the wet brake 10 built in the casing together with the torque converter, any brake capable of adjusting the braking force by hydraulic pressure can be used. The wet type brake, for example, can move in the axial direction via a spline on the rotating shaft, but connects a plurality of rotating plates so as not to rotate, and can move in the axial direction between the rotating plates. Arrange the fixing plate so that it does not rotate. The fixed plate is pressed by the control cylinder driven by hydraulic pressure, and the pressing force with the rotating plate is adjusted. When the control cylinder strongly presses the fixed plate against the rotating plate, the frictional resistance between the fixed plate and the rotating plate increases, and the braking force of the brake increases. Therefore, the braking force of the brake can be adjusted by the force of the control cylinder pressing the fixed plate against the rotating plate. The hydraulic pressure controlled by the brake controller 11 is press-fitted into the control cylinder,
The pressure for pressing the fixed plate against the rotary plate is adjusted to adjust the winding drum 4
To control the braking force. As shown by the chain line, the hoisting drum 4
The disc brake mounted on the rotating shaft of the above is sandwiched between brake pads to adjust the braking force. The pressure at which the brake pads clamp the brake disc is adjusted by a hydraulically driven control cylinder, such as a hydraulic disc brake. The hydraulic pressure controlled by the brake controller 11 is press-fitted into the control cylinder to adjust the pushing pressure of the piston that presses the brake pad to control the braking force of the hoisting drum 4.

The hoist shown in FIGS. 1 to 3 raises or lowers the suspended load in the following manner. When the operating lever 5 is switched to the upper half position of the ascending / descending position 12, the command pulse circuit 17
Increase the count value. As the count value of counter 16 increases, command solenoid valve 19 increases the fluid supply pressure to torque converter 2. In the torque converter 2 in which the supply fluid pressure is increased, the transmission torque is increased, the hoisting torque of the suspended load is increased, and the suspended load is increased. When the suspended load rises, the rotation pulse circuit 15 sends a number of pulses proportional to the rising distance to the counter 16 and subtracts this from the count value. As long as the operation lever 5 is at the ascending position, the command pulse circuit 17 always sends a pulse to the counter 16 at a constant cycle to increase the count value of the counter 16. Therefore,
The suspended load is gradually raised, and the rotation pulse circuit 15 operates so that the count value of the counter 16 is subtracted by the output from the sensor 9.

On the contrary, the operation lever 5 is moved up and down
In the lower half position, the count value of the counter 16 is subtracted by the command pulse circuit 17, and the fluid supply pressure to the torque converter 2 decreases.
Transmission torque decreases and the suspended load descends. When the suspended load drops, the rotation pulse circuit 15 adds the count value of the counter 16 in proportion to the amount of drop and brings the count value of the counter 16 closer to the set value.

When the operating lever 5 is at the rest position, the command pulse circuit 17 does not output an output pulse, and the count value of the counter 16 does not increase or decrease accordingly. In this state, if the suspended load drops for some reason, the number of pulses corresponding to the moving distance is sent from the rotation pulse circuit 15 to the counter 16 and added to the counter 16. When the count value of the counter 16 is added, the transmission torque of the torque converter 2 increases, and the suspended load increases. When the suspended load is raised,
The rotation pulse circuit 15 sends the number of pulses corresponding to the ascending distance to the counter 16, and restores the original count value even if the count value is subtracted. Therefore, the suspended load is controlled so as to always stop at a predetermined position, and the suspended load stands still at a fixed position.

When the operation lever 5 is moved laterally from the stop position 13 of the ascending / descending position 12 to the forced descending position 14, the brake controller 11
0 is operated to stop the suspended load. In this state, when the operating lever 5 is moved to the lower position below the forced lowering position 14, the forward / reverse controller 8 switches the forward / reverse gear 3 to the reverse rotation position, and the command pulse circuit 17 increases the count value of the counter 16. . As the count value of counter 16 increases, command solenoid valve 19 increases the fluid supply pressure to torque converter 2. In the torque converter 2 in which the supply fluid pressure is increased, the transmission torque is increased, the forced drop torque of the suspended load is increased, and the suspended load is forcibly lowered.

When the suspended load descends, the rotation pulse circuit 15 sends a number of pulses proportional to the descending speed to the counter 16,
This is subtracted from the count value. As long as the operation lever 5 is at the forced lowering position 14, the command pulse circuit 17 always sends a pulse to the counter 16 at a constant cycle to increase the count value of the counter 16. Accordingly, the suspended load is forcibly lowered, and the output from the sensor 9 rotates the rotation pulse circuit 15.
Operates to subtract the count value of the counter 16.

When the operation lever 5 is located at the forced lowering position 14, when the brake 10 is released, the suspended load is lowered at a speed higher than the set speed of the operation lever 5. The sensor 9 is used to lower the suspended load at the set speed of the operation lever 5.
Detects the falling speed of the suspended load, and the brake controller 11 controls the braking force of the brake 10 more strongly as the suspended load is faster than the set speed of the operation lever 5. When the descending speed of the suspended load is slower than the set speed of the operation lever 5, the brake controller 11 weakens the braking force of the brake 10,
Increase the descent speed of the suspended load. The brake 10 adjusts the rotating braking force of the hoisting drum 4 to lower the suspended load at the set speed of the operation lever 5.

When the operating lever 5 is raised from the forced lowering position 14 to the stop position 13 after the suspended load is lowered, the suspended load is stopped from falling and the brake controller 1
1 activates the brake 10. In this state, when the operation lever 5 is moved from the forced lowering position 14 toward the rising lowering position 12, the forward / reverse controller 8 detects this and switches the forward / reverse gear 3 to the normal rotating position.

The hoisting machine described above is designed so that the transmission torque of the torque converter 2 increases as the count value of the counter 16 increases. On the contrary, when the count value of the counter decreases, the torque converter increases. Can be designed to increase the transmission torque of the motor.

Further, this hoist has a single counter 16
Controls the transmission torque of the torque converter 2,
It is also possible to control another counter in the ascending / descending position and the forced descending position. Further, without using a counter, the position of the operating lever 5 is detected by a variable resistor or a position sensor, and the output of this position sensor and the output value of the descent rate sensor are arithmetically processed by a microcomputer or the like to generate a torque. It is also possible to control the transmission torque of the converter and the forward / reverse gear.

As shown in FIG. 1 and FIG.
The one provided with the operation lever 5 and controlling both the torque controller 7 and the forward / reverse controller 8 by the operation lever 5 has a feature that the operation can be performed most easily and without fail. However, in the present invention, it is possible to control the torque controller 7 and the forward / reverse controller 8 by separate command means 6 without specifying the command means 6 in this structure.

In this case, the command means 6 may be an operation lever and an operation switch, and an operation switch for forward / reverse switching may be provided at or near the operation lever, and the forward / reverse controller may be controlled by this operation switch. The operation switch has a forced lowering position, and when the operation switch is switched to the forced lowering position, the forward / reverse controller switches the forward / reverse gear to the reverse rotation position.

Further, if attention is paid to the forced descent operation, the torque controller 7 may omit the feedback by the descent rate sensor and simply control the command solenoid valve 19 only by the command means 6. However, in this case, since the position of the suspended load is not detected, it is difficult to operate the stationary of the suspended load and the lifting / lowering speed control. Therefore, the ascending / descending position 12 may be controlled by the descending speed sensor 9, and the forced descending position 14 may be controlled by omitting the feedback by the descending speed sensor 9.

The torque converter 2 shown in FIG. 3 controls the transmission torque by adjusting the pressing force of the clutch 20 with the supplied fluid pressure. In the present invention, the structure of the torque converter 2 is not limited to this structure, and any structure in which the transmission torque can be controlled by the control fluid pressure or electromagnetic force can be used.

Further, the rotation pulse circuit 15 shown in FIG.
The command pulse circuit 17 outputs an addition pulse and a subtraction pulse to separate lines A, B, C, and D. Instead of this circuit, for example, a circuit that emits a pulse corresponding to the displacement amount to one line and sends an identification signal for addition and subtraction to another line can also be used.

[0061]

The control method of the hoist having the torque converter according to the present invention has a feature that a light suspended load can be smoothly lowered at a set ideal speed regardless of the weight of the suspended load. That is, when the method of the present invention lowers the suspended load quickly, the transmission torque of the torque converter is increased to forcibly lower the suspended load, and when the descending speed becomes faster, the brake is braked and adjusted to the set speed. Because you do.

Further, in the control method for the hoisting machine having the torque converter of the present invention, the torque converter forcibly rotates the hoisting drum in the descending direction in the state where the hoisting drum is braked to the descending speed of the suspended load by the brake. The torque converter attempts to force the load down, and the brakes brake the load drop. The method of the present invention does not open the brake to force the torque converter to drop the suspended load.
The torque converter rotates the hoisting drum with a torque larger than a torque for lowering a light suspended load at a set speed.
If the hoisting drum is rotated in this state, the suspended load is accelerated to a state where the descent speed is too high, so that the rotation of the hoisting drum is braked by the brake. When the descent speed of the suspended load reaches the set speed, the rotation of the hoist drum is braked to lower the suspended load at the set speed. The method of the present invention in which the hoisting drum is accelerated by this method has a feature that the transmission torque of the torque converter can be set to a large value, so that a light suspended load can be rapidly accelerated and lowered at a set speed in a short time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an outline of a hoisting machine that realizes a control method of the present invention.

FIG. 2 is a front view showing a moving position of an operating lever of the hoisting machine shown in FIG.

FIG. 3 is a sectional view showing an example of a torque converter of the hoist shown in FIG. 1;

FIG. 4 is a block diagram showing a conventional hoist.

FIG. 5 is a block diagram showing another conventional hoist.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Prime motor 1A ... Engine 2 ... Torque converter 3 ... Forward / reverse gear 4 ... Hoisting drum 5 ... Operating lever 6 ... Command means 7 ... Torque controller 8 ... Forward / reverse controller 9 ... Sensor 10 ... Brake 11 ... Brake controller 12 ... Ascend Lowering position 13 ... Stopping position 14 ... Forced lowering position 15 ... Rotation pulse circuit 16 ... Counter 17 ... Command pulse circuit 18 ... Adjusting means 18A ... D / A converter 19 ... Command solenoid valve 20 ... Clutch 21 ... Torque converter body 22 ... Clutch pressure adjusting cylinder 23 ... Clutch pushing plate 24 ... Multi-plate clutch 25 ... Output shaft 26 ... Impeller 27 ... Turbine 28 ... Gear S ... Control means

Claims (1)

(57) [Claims] An engine (1) is rotated by a torque converter.
(2) and the transmission to the hoisting drum (4) via the forward / reverse gear (3) .When lowering the heavy suspended load, the hoisting drum (4) is lifted by the forward / reverse gear (3). When driving in the lifting direction and lowering a light suspended load, switch the forward / reverse gear (3),
In the control method of the hoisting machine driven in the direction of lowering the suspended load with the hoisting drum (4), when lowering the light suspended load, the torque converter (2)
The torque converter (2) can be adjusted by adjusting the transmission torque of the
The transmission torque of the hoisting drum (4), and the sensor (9) detects the descending speed of the suspended load with the sensor (9).
By controlling the brake (10) that controls the rotation of the hoisting drum (4) when the suspended load becomes faster than the set speed, the rotation of the hoisting drum (4) is braked.
Furthermore, the transfer torque of the torque converter (2) is adjusted so as to reach a set speed in a state where the brake (10) controls the rotation of the hoisting drum (4). Machine control method.