JPS60153396A - Limiter for free rate of fall of hung load in hydraulic driving winch for crane - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a crane in which a winch drum equipped with a brake TL- which is braked by a spring force and released by a hydraulic cylinder is rotatably driven by a hydraulic motor via a clutch. This invention relates to a free-fall speed limiting device for shipping in an oil spill drive winch.

This type of hydraulically driven winch is capable of hoisting and lowering a suspended load by rotating the winch drum with a hydraulic motor via a clutch with the brake removed by the hydraulic cylinder, or by using the brake with the hydraulic cylinder. By releasing the winch drum and disengaging the clutch, the winch drum can be rotated freely and the suspended load can be lowered freely. The free-falling function of a hanging load reduces the work efficiency of a crane because it allows shipments to be lowered quickly. However, if this free-falling speed becomes too fast, the hanging load may not be able to stay in place while it is being lowered. When stopping the winch drum, it is necessary to brake the winch drum with an extremely large braking force, which causes excessive force to be applied to the winch drum, wire rope, and structural parts of the crane.
Since there is a risk of damaging these parts, all of the winch drums are artificially braked to prevent the lowering speed of the suspended load from becoming too large during the free descent of shipping.

However, in order to prevent the free-falling speed of the suspended load from exceeding the allowable speed by artificially braking the winch drum, the allowable speed varies depending on the magnitude of the load corresponding to the suspended load, that is, when the load is small, the allowable speed When the load is large, the permissible speed decreases, so it is necessary to fully recognize this relationship and brake the winch drum, which causes a great deal of stress and stress on the operator.Purpose of the present invention is the free-falling speed of a suspended load on a hydraulically driven winch of a crane, which is automatically controlled so that the free-falling speed does not exceed the maximum allowable descent speed determined by the size of the load corresponding to the suspended load. By providing a restriction device, it is intended to reduce the stress on the operator. In order to achieve this object, the present invention is constructed as follows. That is, the shipping free fall speed limiting device for a hydraulically driven winch of a crane according to the present invention rotates a winch drum equipped with a brake that is braked by a spring force and released by a hydraulic cylinder by a hydraulic motor via a clutch. A free-falling speed limiting device for shipping in a hydraulically driven winch of a crane, which is configured to control the hydraulic pressure supplied to the oil field cylinder of the brake to adjust the brake collar, and the rotation of the winch drum. A shipping descent speed detector that detects the speed or payout speed of the wire rope wound on the winch drum as an actual descent speed signal, an actual load signal generator that outputs the load corresponding to the actual suspended load as an actual load signal, and an arithmetic calculation unit that outputs a control signal for controlling the brake control pulp,
The arithmetic calculation unit stores the maximum allowable descent speed for each load corresponding to each suspended load, and uses the stored value to convert the actual load signal of the actual load signal generator into an intex signal corresponding to the actual suspended load. The system is configured to obtain a maximum allowable descent speed signal, compare this maximum allowable descent speed signal with an actual descent speed signal from the shipping descent speed detector, and output a control signal for controlling the brake control pulp based on the comparison result. When the suspended load is freely lowered, the system automatically prevents the lowering speed of the suspended load from exceeding the maximum allowable lowering speed specified by the size of the load corresponding to the suspended load. It is a restriction.

6 Embodiments of the present invention will be described in detail below with reference to the drawings.

(First Example) In FIG. 1, 1 is a hydraulically driven winch for a crane, and this hydraulically driven winch 1 has a winch drum equipped with a brake 4 which is braked by a spring 2 and released by a hydraulic cylinder 3. 5 is rotationally driven by a hydraulic motor 7 via a clutch 6. 8 is
A wire rope 8 is wound around the winch drum of the hydraulically driven winch 1, and this wire rope 8 is pulled out through a guide sheave 9 provided at a suitable location on a crane (not shown), and the shipment 10 is suspended there. I am working hard to get it down. In a crane having a boom portion such as a mobile crane, the guide sheave is provided at the tip of the boom, and the suspended load 10 is suspended from the tip of the boom. Reference numeral 11 denotes a brake control pulp that controls the hydraulic pressure supplied to the cylinder 3 of the brake 4 to control the brake pressure, and includes a supply circuit 12, a sieve pressure circuit 13, and a tongue circuit 14 for supplying the hydraulic cylinder 3 to the hydraulic cylinder 3. It is interposed in between. 15 is a shipping descent speed detector that detects the rotational speed of the winch drum 5 and outputs the detection result as a descent speed signal of the suspended load 10. In other embodiments, this shipping descent speed detector may be configured to detect the rotation of the guide sheep 9 and detect the unwinding speed of the wire rope 8. The actual load signal generator outputs the unloading signal W, which in this embodiment is manually adjusted by the operator. Reference numeral 17 denotes an arithmetic control unit that outputs a control signal 0 for controlling the brake control pulp 11, and this arithmetic control unit 17 stores the maximum allowable descending speed for each suspended load and calculates the above-mentioned speed from this stored value. a maximum permissible lowering speed output section signal 18 that outputs a small maximum permissible lowering speed signal Vi corresponding to the load of the suspended load 10 actually suspended using the actual unloading signal W of the actual load signal generator 16 as an index signal; It receives the maximum allowable descending speed signal V from the maximum allowable descending speed signal output section 18 and the actual descending speed signal V from the shipping descending speed detector 15, compares the two, and operates the brake control valve 11 according to the comparison result. It is composed of a comparator 19 that outputs a control signal C for control. The control signal C output from the arithmetic control section 17 is transmitted to the comparison section 19.
The closer the actual descent speed signal K input to #1 is to the maximum allowable descent speed signal V, that is, the closer the descent speed of the shipment 10 is to the maximum allowable descent speed defined by the load of the suspended load 10, the more the brake control valve 11 It is associated with the brake control valve 11 so as to reduce the hydraulic pressure of the supply/discharge circuit 12 to the hydraulic cylinder 3 and increase the braking force. In the case of this embodiment, the brake control valve 11 is
When de-energized, the supply/discharge circuit 12 and the tank circuit 14 are connected to make the hydraulic pressure supplied to the hydraulic cylinder 3 zero, and when energized, the supply/discharge circuit 12 and the high-pressure circuit 13 are connected, and the hydraulic pressure supplied to the hydraulic cylinder 3 is connected to the high-pressure circuit. The calculation unit 17 is configured with a solenoid pulp configured to have a hydraulic pressure of 13, and the lowering speed of the suspended load 1o is sufficiently smaller than the maximum allowable lowering speed specified by the load of the suspended load 10. Sometimes, the control signal C becomes a frequently pulsed electric signal (or a continuous energization signal), and the lowering speed of the suspended load 10 is controlled by the shipment 1.
The control signal C is configured to become a pulse electric signal that becomes sparser as it approaches the maximum allowable descending speed defined by a load of zero. Brake control valve 11 configured as described above
Frequent pulsed electrical signals (or continuous electrical signals)
is applied, the brake control valve 11 closes the supply/discharge circuit 1
2 and the high pressure circuit 13, and as a result, the hydraulic cylinder 3 resists the spring 2 and fully releases the brake 4. Further, as the pulse electric signal applied to the brake control valve 11 gradually becomes sparse, the brake control valve 1] will be connected to the supply/discharge circuit 12 to the tank circuit 14.
As a result, the oil pressure supplied to the supply/discharge m1 passage 12 gradually decreases.
As a result, the braking force gradually increases. Reference numeral 20 denotes a brake pedal, and this brake pedal 20 is connected to the brake 4 so that the brake 4 is braked when the brake pedal 20 is depressed.

When the winch drum 5 is driven by the O hydraulic motor 7, the operation of which will be explained next, the clutch 6 is connected and the hydraulic motor 7 is rotated. The actual load signal generator 16 is adjusted to output an actual load signal W corresponding to the load of the load 10. When the winch drum 5 is stopped or when the winch drum 5 is driven by the hydraulic motor 7, the lowering speed of the suspended load 10 is sufficiently smaller than the maximum allowable lowering speed defined by the load of the suspended load 10. Therefore, the control signal O output from the calculation unit 17 is
Frequent pulsed electrical signals (-! continuous electrical signals)
The brake control valve 11 is connected to the supply oil path 12.
and high pressure oil line? ...The pressure cylinder 3 is used to release the brake 4 against the spring 2. therefore,
The winch drum 5 is rotationally driven by a rill motor 7 and drives the suspended load 10 to be hoisted and hoisted down. When the suspended load 10 is to be freely lowered, disconnect the clutch 6,
To enable the winch drum 5 to rotate freely. As a result, the suspended load 10 freely descends due to its own weight. When the free descent speed of the suspended load 10 is sufficiently smaller than the maximum allowable descent speed A defined by the suspended load 10, the control signal 0 output from the calculation section 17 as described above is a frequent pulse electric signal. (or a continuous electrical signal), the brake control valve 11 connects the supply oil path 12 and the Shimada oil path 13, causes the hydraulic cylinder 3 to release the brake 4 against the spring 2. When the free descent speed of the shipping lO approaches the maximum allowable descent speed defined by the load of the hanging load 10, the control signal O output from the calculation unit 17 gradually becomes a sparse pulse electric signal.Brake control pulp 11
is controlled by the pulse electric signals that become increasingly sparse, so the oil pressure supplied to the oil supply/drainage path 12 gradually decreases. As a result, the output of the hydraulic cylinder 11 housing the brake 4 against the spring 2 decreases, and the braking force of the brake 40 gradually increases. That is, the braking force automatically increases as the suspended load 10 approaches its maximum allowable descending speed,
The suspended load 10 is automatically adjusted so as not to exceed its maximum allowable lowering speed. In addition, when trying to stop a hanging load in a free-falling position at a desired position, please press brake pedal 2.
0 to brake the winch drum 50 rotations.

(Second Example) In the first example described above, the operator manually adjusts the actual load signal generator 16 according to the load of the suspended MIO. As shown in Figure 2, the load corresponding to the load of the suspended load 10 is a three-point sheave installed in the middle of the wire lobe 8.-7 Nose 4 A load detector 16' that detects the puller tension and outputs the detection result. When the switch 21 is connected, the output value of the load detector 16' at the time when the switch 21 is connected is stored, and this stored value is output as long as the switch 21 of the actual load signal generator 16 is connected. The load signal setting section 22 may be configured to output the detection result of the load detector 16' as the output of the actual load signal generator 16 in real time when the switch 21 is turned off. And before shipping i.e. free fall state I
It is operated in conjunction with the operation of the clutch 6 so that it is connected when the clutch is engaged, that is, when the hydraulic motor 7 is ready for hoisting and lowering the shipment. I'm here.

Next, the operation of this second embodiment will be explained. When the winch drum 5 is driven by the hydraulic motor 7, the switch 21 is turned off, and the actual load detector 16 outputs the detection result of the load detector 16' which outputs a signal corresponding to the load of the suspended load 10. Output as signal W. winch drum 5
When the winch drum 5 is stopped or the winch drum 5 is driven by the hydraulic motor 7, the descending speed of the suspended load 10 is sufficiently smaller than the maximum allowable descending speed defined by the load of the suspended load 1o, so the calculation Since the control signal output from the calculation unit 17 is a frequently pulsed electrical signal (or continuous electrical signal), the brake 41d is released as in the first embodiment. Therefore, the winch drum 4 can drive the suspended load 1o up and down by controlling the rotation of the hydraulic motor 7. When the suspended load 10 is to be freely lowered, the clutch 6 is disengaged to allow the winch drum 5 to rotate freely. As a result, the suspended load 1o freely descends due to its own weight. The suspended load 10 begins to freely descend. ! -To the load removal detector 16-
The load detector 16' will no longer detect the load that responds to the load of the suspended load 1 (if it is shipped or falls freely, the load acting on the load detector 16' will be greater than the value that responds to the load of the suspended load 10). However, before the suspended load 1o starts free falling, that is, when the clutch 6fc is disconnected, the switch 21 of the load signal setting section 22 is turned on, so the actual generation timing of the load signal generator 16 is No. 1 continues to output the output signal of the load detector 16' before the suspended load 1o starts free falling, that is, the value corresponding to the load of the suspended load 1O, as the actual load signal W. When the free descent speed is sufficiently smaller than the maximum allowable descent speed specified by the suspended load 10, the brake 4 is released;
The first feature is that as the free descent speed of the shipment 1o approaches the maximum allowable descent speed, the braking force of the brake 4 is gradually increased and automatically adjusted so as not to exceed the maximum allowable descent speed for the hanging load force. The effect is the same as in the embodiment.

In this second embodiment, the actual load signal generator 16 is automatically set, so the operator's stress is reduced compared to the first embodiment (in the first embodiment, the operator manually sets the actual load signal generator 16). This has the effect of further reducing the amount of damage compared to the previous method.

Note that the actual load signal W of the actual load signal generator 16 for detecting the load responsive to the load of lifting t%'Ilo may be as in the first and second embodiments above, but Of course, the ratio of the actual load of the hanging load 10 to the lifting load (i & large allowable lifting load) may be used as the actual load signal W.

As explained in detail above, the device for limiting the free descent speed of a suspended load in a hydraulically driven winch of a crane according to the present invention has a simple configuration, but it is capable of controlling the free descent speed of shipping to the maximum specified by the commercially suspended load. Since the descent speed is automatically limited to within the allowable range, the operator's stress can be greatly reduced.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a shipping free fall speed limiting device in a hydraulically driven winch of a crane according to the present invention, and FIG. 2 is an explanatory diagram of another embodiment of the same. Spring; 2, oil field cylinder: 3, brake; 4, winch drum; 5, clutch; 6, ? Yamada motor; 7; Brake control valve; 11; Hanging load lowering speed detector; 15; Actual load signal generator; 16; Calculation unit; 17

Claims (1)

[Claims] A hydraulically driven winch for a crane, comprising a winch drum equipped with a player that is braked by a spring force and released by a hydraulic cylinder, and is rotatably driven by a hydraulic motor via a clutch. A hanging load free descent speed limiting device in which the brake cylinder e is controlled by controlling the hydraulic pressure supplied to the hydraulic cylinder of the brake.
A shipping descent speed detector that detects the brake control pulp, the rotational speed of the winch drum, or the unwinding speed of the wire rope wound on the winch drum as an actual descent speed signal, and the actual load corresponding to the actual suspended load. It consists of an actual load signal generator that outputs as a load signal, and a calculation unit that outputs a control signal to control the brake control pulp, and the calculation unit calculates the maximum allowable descending speed for each load corresponding to each shipping load. The actual load signal ? of the actual load signal generator is stored from this stored value. A maximum permissible lowering speed signal corresponding to the actual shipping load is obtained as an index signal, and this maximum permissible lowering speed signal is compared with the actual lowering speed signal from the suspended load lowering speed detector, and the brake control pulp is controlled based on the comparison result. A device for limiting the free descent speed of a suspended load in a hydraulically driven winch of a crane, the device being configured to output a control signal for controlling a crane.