JPH0537884U - Load drop prevention device for hoisting device - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose of the present invention is to provide a hoisting device that is safe and has excellent operability, by eliminating the problem of unexpectedly unwinding the luggage for a moment at the moment of hoisting operation. A detector 27 for calculating the holding pressure of the hydraulic motor 1 from the rope tension F calculated by the moment limiter calculating unit 21 and detecting the holding pressure of the hoisting motor is provided. The holding pressure obtained in step 1 was compared with the actual holding pressure so that the brake was not released until the two pressures substantially matched only during winding.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hanging load drop prevention device for a hoisting device. The present invention relates to a safe and easy-to-operate hoisting device that eliminates the problem of suddenly hoisting a load in a hydraulic hoisting device that employs an automatic brake. ..

[0002]

[Prior Art]

 FIG. 3 shows a hydraulic hoisting device, 1 is a hydraulic motor, 2 is a speed reducer for increasing the torque of the hydraulic motor 1, 3 is an output shaft for taking out the output of the speed reducer 2, and 4 is an output. A clutch that is connected to the shaft 3 and that transmits a rotational force to the wire-drum 5. Reference numeral 6 is a break for holding the wire drum 5 in a non-rotatable manner.

FIG. 4 is a hydraulic circuit of a conventional hoisting machine, 7 is a counter-balance valve for holding a load with hydraulic pressure, 8 is a directional flow control valve for controlling the rotating direction and speed of the hydraulic motor 1. Reference numeral 9 is a remote control valve for generating a hydraulic pressure for switching the directional flow control valve 8, 10 is a shuttle valve for selecting a high pressure between the winding upper side pilot pressure and the lower side pilot pressure generated by the remote control valve 9, and 11 is a remote control valve 9 operated. It is a pressure switch that detects whether or not it has been activated. Reference numeral 16 is a conduit between the motor 1 and the counter balance valve 7, and 17 is a drain conduit of the motor.

FIG. 5 shows a conventional automatic brake release mechanism, 18 is a power source, 12 is a solenoid valve for turning on / off the automatic brake, and 13 is a hydraulic cylinder for releasing the brake. ..

FIG. 6 shows the operating mechanism of the hoisting device, in which the load 15 is suspended from the rope 14 wound around the drum 5.

[0006]

Operation of the conventional device When the remote control valve 9 is operated to the side a now, the pilot pressure Pa is generated, the control valve 8 is moved to the left, and the discharge oil of the pump (not shown) is checked by the counter-balance valve 7. The valve is pushed open and passes through the pipe line 16 to generate a pressure PA corresponding to the load 15 to rotate the hydraulic motor 1. The rotation of the hydraulic motor 1 is increased in torque by the reduction gear 2 to rotate the output shaft 3. The rotation of the output shaft 3 is transmitted to the drum 5 via the clutch 4 to rotate the drum. A load 15 for winding up the rope 14 is wound up.

At the same time, the pressure Pa operates the pressure switch 11 (FIG. 5) and a current flows through the solenoid valve 12 to switch the pressure. The pressure of the pilot hydraulic source flows into the hydraulic cylinder 13 for releasing the brake. Release the brake 6.

Next, when the remote control valve 9 is returned to neutral, the oil passage 19 is connected to the tank and Pa ≈ 0, and the directional flow rate adjusting valve 8 returns to neutral by the force of the spring, and the oil to the motor 1 is returned. The supply stops and the motor stops rotating. At this time, the hydraulic motor 1 receives a force for reversing the load 15 and the oil confined in the pipe 16 is compressed by this force and the counter balance valve 7 to generate a pressure PA. It supports this.

On the other hand, when Pa≈0, the pressure switch 11 is returned to the neutral position, the solenoid valve 12 is also returned to the neutral position by the spring, the hydraulic cylinder 13 is connected to the tank, and the hydraulic cylinder 13 is pushed back by the force of the spring. Then, the brake 6 is operated by the spring force, and the load 15 is supported by the brake 6.

If left in this state, the oil trapped in the conduit 16 escapes to the tank via the drain conduit 17 as an internal leak of the hydraulic motor 1. At this time, the amount of oil that escapes was ΔQ ₁ as the oil in the conduit 16 was compressed by the pressure PA, and the torque transmission mechanism was deformed by the torque generated by the load 15. After the load is applied, the torque is not applied and the deformation occurs ΔQ ₂ minutes accompanying the rotation that occurs when it returns to its original state. After this much oil has leaked, the pressure in pipe 16 is almost It becomes 0.

Next, when the remote control valve 9 is operated again to the upper side of the winding, the brake 6 is released and the load 15 is supported by the hydraulic pressure as described above, but the supply of the oil from the pump is not proper, The holding pressure is almost 0 as described above, and the drum rotates by the load until the holding pressure rises to PA. The amount of rotation at this time is equivalent to the above-mentioned leak amount, and if the motor absorption amount is q and the reduction ratio is i, the rotation is as shown in the attached formula 1.

[0012]

[Equation 1]

Therefore, the operator is extremely dangerous because the load falls for a moment despite the winding operation.

[0014]

[Problems to be solved by the device]

 It is an object of the present invention to provide a hoisting device that is safe and has excellent operability by eliminating the problem that the luggage unwinds for a moment unintentionally at the moment of hoisting operation.

[0015]

[Means for Solving the Problems]

 A pressure sensor 20 for calculating the holding pressure of the hydraulic motor 1 from the rope tension F calculated by the moment limiter calculation unit 21 and detecting the holding pressure of the hoisting motor is provided. The holding pressure obtained in step 2 was compared with the actual holding pressure to prevent the brake from being released until the two pressures almost matched during winding.

[0016]

【Example】

 A description will be given based on FIG. In contrast to the hydraulic circuit of the known device shown in FIG. 4, a pressure sensor-20 and a moment limiter calculation unit 21 are added to the conduit 16. A hoisting detection limit switch 27 is provided in the oil passage 19 and is connected to the moment limiter computing unit 21. As shown in FIG. 1 (b), the moment limiter computing unit 21 is provided with a relay 22 in the moment limiter computing unit in the automatic brake releasing mechanism.

FIG. 2 shows an example of the moment limiter. Reference numeral 26 is a boom, 28 is a support rope that supports the boom, 29 is a tension detector that detects the tension of the support rope, and 23 is an angle detector that measures the angle of the boom. Reference numeral 24 is a drum rotation detector, 25 is a display, and 21 is a calculation unit of the moment limiter.

The moment limiter calculation unit 21 is a radius of the load 15 calculated from the boom angle detected by the angle detector 23 and a fall motion of the boom 26 detected by the tension detector 29 and a calculation device. The weight of the load 15 is calculated based on the data stored therein, and the tension F per loop and the loop 14 wound around the drum 5 by the drum rotation detector 24 are calculated. The radius R (FIG. 6) can also be detected.

[0019]

[Operation]

 The torque applied to the output shaft 3 from the rope tension F and the radius R of the rope calculated by the moment limiter calculation unit 21 can now be obtained by T = FR. The holding pressure PA required to support this torque T can be calculated by the attached mathematical expression 2 (η is efficiency).

[0020]

[Equation 2]

Since i, q and η are known, PA is calculated by the moment limiter calculating unit 21 from the equation.

Now, when the hoisting operation is performed, the hoisting detection switch 27 is activated to inform the moment limiter calculation unit 21 that the hoisting is being carried out. At this time, the moment limiter calculation unit 21 reads the output P of the pressure sensor-20 of the conduit 16 and activates the relay-22 when P≈PA. At this time, since the pressure switch 11 has already been operated, when the relay 22 is operated, the solenoid valve 12 is switched, the hydraulic cylinder 13 is operated, and the brake 6 is released.

Thus, at the time when the break 6 is released, sufficient pressure is generated to hold the load 15, so that the reverse rotation phenomenon of the drum 5 does not occur, the load does not drop, and it can be safely wound up. You can

In the present invention, the compensation at the time of unwinding is not performed, but the fall at the time of unwinding is because it coincides with the intention of the operator, so that there is no danger involved.

[0025]

【effect】

 A pressure sensor 20 for calculating the holding pressure of the hydraulic motor 1 from the rope tension F calculated by the moment limiter calculation unit 21 and detecting the holding pressure of the hoisting motor is provided. The holding pressure obtained in step 2 was compared with the actual holding pressure to prevent the brake from being released until the two pressures almost matched during winding. In this way, it was possible to provide a hoisting device that is safe and has excellent operability by eliminating the problem that the luggage unwinds for a moment unintentionally at the moment of hoisting operation.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of the present invention.

FIG. 2 shows an example of a moment limiter.

FIG. 3 is a schematic view of a known hydraulic hoist.

FIG. 4 is a hydraulic circuit diagram of a known hydraulic hoist.

FIG. 5 is a known automatic brake releasing mechanism.

FIG. 6 is a perspective view of the hoisting device in an operating state.

[Explanation of symbols]

1 Hydraulic Motor 2 Reducer 3 Output Shaft 4 Clutch 5 Wire-Drum 6 Break 7 Counter-Balance Valve 8 Directional Flow Control Valve 9 Remote Control Valve 10 Shuttle Valve 11 Pressure Switch 12 Solenoid Valve 13 (For Break Release) ) Hydraulic cylinder-14 Rope 15 Load 16 Pipe line 17 Drain line 18 Power supply 19 Oil line 20 Pressure sensor-21 Moment limiter calculation unit 22 Relay 23 Angle detector 24 Detector 25 Display unit 26 Boom 27 Hoisting detection switch 28 Support rope 29 Tension detector

Claims (1)

[Scope of utility model registration request] 1. A holding pressure of a hydraulic motor (1) is calculated from a rope tension F calculated by a moment limiter calculating section (21) to detect the holding pressure of a hoisting motor. It is characterized in that a pressure sensor (20) is provided, the holding pressure obtained by the above calculation is compared with the actual holding pressure, and the brake is not released until both pressures substantially match only during winding. Load drop prevention device for hoisting equipment.