JP2004244143A - Hanging balance - Google Patents

Abstract

An object of the present invention is to reduce cost and simplify a hydraulic control system.
In a suspension balance having a plurality of hydraulic cylinders and suspending a load at multiple points, each hydraulic cylinder has a head side and a rod side connected to each other by a closed circuit oil pipe. A throttle valve and an accumulator 54 are provided in this oil pipe, and the load of the suspended load 14 acts in a direction to push the rod of each hydraulic cylinder 34 into the cylinder. The suspension balance 20 is formed by fixing four actuators 22A, 22B, 22C, 22D each containing a hydraulic cylinder 34 in a casing 24 in a horizontal state.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lifting balance used for lifting a load by a crane, and more particularly to a lifting balance in which a plurality of hydraulic cylinders are used to suspend a load at multiple points.
[0002]
[Prior art]
When a large and heavy load is lifted by a crane, a lifting balance is used to stably maintain the posture of the load. Patent Document 1 discloses an example of such a hanging balance. FIG. 7 is a perspective view of a hanging balance similar to that described in Patent Document 1. A suspended load 2 which is a heavy load is placed on the loading platform 1, and a suspended balance 4 is used when the suspended load 2 is lifted by the crane 3. The suspension balance 4 has a total of four hydraulic cylinders 6 attached to corners of a rectangular suspension frame 5. The suspended load 2 is lifted by the crane 3 by connecting the suspension rope 8 engaged with the tip of the rod 7 of each hydraulic cylinder 6 to the carrier 1 at four points. A control box 9 for controlling the operation of each hydraulic cylinder 6 is attached to the suspension frame 5, and a remote controller 10 for remote control is connected to the control box 9.
[0003]
At the time of lifting, the most dangerous is the moment when the suspended load 2 leaves the ground. That is, when the installation surface of the suspended load 2 is inclined or when the center of gravity of the suspended load 2 is largely deviated, the loading platform 1 largely swings at the moment of the ground cutting. As a result, there is a danger that the suspended load 2 may be collapsed or that the pallet 1 may collide with nearby workers or objects. In order to prevent such a lateral run-out at the time of the ground separation, it is sufficient that the four suspension points on the carrier 1 rise almost at the same time as the ground separation. For this reason, when lifting the landing load 2, first, the lifting balance 4 is pulled up by the crane 3 by a very small amount. Then, in a normal case, one or two of the four suspension points on the loading platform 1 are lifted off the ground, and the remaining suspension points are in a one-sided up state. Therefore, the entire loading bed 1 is landed again by individually extending the rods 7 of the hydraulic cylinders 6 corresponding to the raised hanging points. Thereafter, when the same operation is repeated several times, a plurality of suspension points of the loading platform 1 are lifted almost simultaneously at the time of ground separation, and safe lifting can be performed.
The above operation is performed by an operator on the ground remotely operating each hydraulic cylinder 6 with the hand controller 10.
[0004]
[Patent Document 1]
JP 2001-19351 A
[Problems to be solved by the invention]
However, in order to drive each hydraulic cylinder 6, it is necessary to equip each hydraulic cylinder 6 with a hydraulic pump system and a hydraulic control system provided with various switching valves. For this reason, the equipment cost of the hydraulic cylinder 6 becomes expensive, and the control system for individually controlling the plurality of hydraulic cylinders 6 is disadvantageously complicated. In particular, when the weight of the suspended load reaches several tens of tons, the equipment specifications such as the hydraulic pump must also correspond to the weight of the suspended load, and as a result, the cost of the suspended balance is increased.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a suspension balance which can solve the above-mentioned drawbacks of the prior art and can reduce the cost and simplify the control system of the hydraulic cylinder.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a suspension balance according to the present invention is a suspension balance including a plurality of hydraulic cylinders and suspending a load at multiple points, wherein each of the hydraulic cylinders has a head side and a rod side. Are communicated with a closed circuit oil pipe, and a throttle valve and an accumulator are provided in the oil pipe, and the load of the suspended load acts in a direction of pushing the rod of each hydraulic cylinder into the cylinder. .
[0007]
Further, the hanging balance according to the present invention is characterized in that actuators each accommodating the hydraulic cylinders in a casing are formed for each hydraulic cylinder, and these actuators are fixed to each other in a horizontal state.
In the suspension balance having the above configuration, it is preferable that a gas spring is connected to a rod of each of the hydraulic cylinders.
[0008]
[Action]
The present invention focuses on the fact that the load of a suspended load acts on a hydraulic cylinder only in one direction in a suspension balance, and utilizes the load of the suspended load as a driving force of the hydraulic cylinder. In a hydraulic cylinder according to the present invention, a throttle valve provided in a closed circuit oil pipe is normally closed, and there is no mutual movement of hydraulic oil between a head side and a rod side of the cylinder. When it is desired to lower the suspension point of the suspended load locked to the hydraulic cylinder, the throttle valve is opened. Then, the hydraulic oil on the head side of the hydraulic cylinder moves to the rod side by the load of the suspended load, the rod is pushed into the cylinder, and the suspension point of the suspended load can be lowered. The amount of increase or decrease in the hydraulic oil in the cylinder caused by the movement of the hydraulic oil is absorbed by an accumulator provided in a closed circuit oil pipe. The hydraulic cylinder does not need to be equipped with a complicated hydraulic control system including a hydraulic pump system and various switching valves. Therefore, it is possible to reduce the cost of the hanging balance and simplify the control system of the hydraulic cylinder.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 4 show a hanging balance 20 according to a first embodiment of the present invention. FIG. 1 is a partially cutaway side view, FIG. 2 is a partially cutaway plan view, FIG. 3 is a perspective view, and FIG. FIG. 4 is an explanatory diagram of an actuator that is A suspended load 14 which is a heavy load is placed on the loading platform 12, and a suspended balance 20 is used when the suspended load 14 is lifted by the crane 18.
[0010]
The hanging balance 20 has four elongated actuators 22 fixed to each other in a horizontal state. The suspension ropes 16A, 16B, 16C, 16D hanging from the actuators 22A, 22B, 22C, 22D are located at the four symmetrical points, and the suspension ropes 16 are locked with the suspension points 15 provided on the loading platform 12. . 1 and 2 show the inside of the actuator 22A among the four actuators 22, and show only the outer shape of the other actuators 22. FIG. Each actuator 22 has a cylindrical casing 24. The side walls of the actuators 22A and 22B are joined back to back, the suspension rope 16A side of the actuator 22A projects to the left, and the suspension rope of the actuator 22B. The 16B side projects to the right. Similarly, the side walls of the casings 24 of the actuator 22C and the actuator 22D are joined back to back, the suspension rope 16C side of the actuator 22C protrudes forward, and the suspension rope 16D side of the actuator 22D protrudes rearward.
[0011]
Then, the center of the lower surface of the casing 24 of the actuator 22A and the actuator 22B and the center of the upper surface of the casing 24 of the actuator 22C and the actuator 22D are joined, and the four actuators 22 are integrated. Although the actuators 22A and 22B and the actuators 22C and 22D are perpendicular to each other, they need not necessarily be perpendicular to each other, and may intersect at an angle of 60 degrees in order to cope with an elongated suspended load. A reinforcing plate 26 is welded to the center of the upper surface of the casing 24 of the actuator 22A and the actuator 22B, and a suspending fitting 28 is attached to the reinforcing plate 26. The hanging fitting 28 is connected to the hook 32 of the crane 18 by the wire 30, and the suspended load 14 is suspended by the crane 18 via the hanging balance 20 and the bed 12.
[0012]
A hydraulic cylinder 34, a moving pulley 36, a constant pulley 38, and a gas spring 40 are accommodated in the casing 24 of each actuator 22. The cylinder 34 is a normal single-rod double-acting cylinder, and a moving pulley 36 is attached to a tip 44 of a rod 42. One end of the suspension rope 16 is fixed to the casing 24, passes through a moving pulley 36 and a constant pulley 38, and the other end is locked to a suspension point 15 provided on the loading platform 12. As a result, the load of the suspended load 14 acts to push the rod 42 into the hydraulic cylinder 34. The gas spring 40 has a cylinder fixed to the casing 24 and a rod distal end connected to the moving pulley 36.
[0013]
The head side 46 and the rod side 48 of the cylinder 34 are connected by a closed circuit oil pipe 50, and a throttle valve 52 and an accumulator 54 are arranged in the oil pipe 50. The oil pipe 50 is provided with a bypass valve 58 having a check valve 56 that bypasses the throttle valve 52. The check valve 56 prevents the flow of the hydraulic oil from the head side 46 to the rod side 48 and allows the flow of the hydraulic oil from the rod side 48 to the head side 46 to be free. The accumulator 54 has a structure in which the internal volume of the hydraulic oil storage portion in contact with the compressed gas portion via a bladder or piston (not shown) can be changed according to the oil pressure. Due to the pressure of the nitrogen gas sealed in the compressed gas portion of the accumulator 54, when the load of the suspended load 14 is not acting on the rod 42, the hydraulic pressure of the cylinder system is maintained at about p = 300 kPa. In this state, the hydraulic pressures on the rod side 48 and the head side 46 are the same, so that the cylinder force of the rod sectional area A × the hydraulic pressure p acts on the rod 42 in a direction to push the rod 42 out of the cylinder 34. Due to this cylinder force, the rod 42 is pushed out of the cylinder 34 against the frictional resistance between the piston 35 and the inner wall of the cylinder 34, and is located at the right end of the rod side 48. The throttle valve 52, the accumulator 54, and the check valve 56 are arranged outside the casing 24, and are connected to the cylinder 34 in the casing 24 by an oil pipe 50 penetrating the casing 24.
[0014]
In the above state, when suspending the suspended load 12, the throttle valve 52 of the oil pipe 50 of each actuator 22 is closed. Next, when the crane 18 is operated and the suspension balance 20 is pulled up, each suspension rope 16 is tensioned, and the load of the suspended load 14 acts on the rod 42. At this time, since the load direction is changed by the fixed pulley 38 and the moving pulley 36, the load of the suspended load 14 acts in the direction of pushing the rod 42 into the cylinder 34. However, since the throttle valve 52 of the oil pipe 50 is closed on the head side 46 of the cylinder 34 and there is no escape route for the hydraulic oil, the internal pressure increases due to the load of the suspended load 14 on the head side 46, but the rod 42 Will not be pushed into.
[0015]
By the way, as described in the section of the related art, in order to prevent the lateral swing of the suspended load 14 suspended at the multiple points at the time of the ground separation, the suspended suspension point 15 that floats up in a one-sided situation may be landed again. . In FIG. 1, when one of the hanging points 15 is floating in such a one-sided situation, it is necessary to temporarily land the hanging point 15. In order to execute the landing, the throttle valve 52 of the corresponding actuator 22 is opened. Then, the hydraulic oil in the head 46 whose internal pressure has increased due to the load of the suspended load 14 flows to the rod 48 via the throttle valve 52. As a result, the rod 42 is pushed into the head side 46. As the rod 42 is pulled into the cylinder 34, the suspension point 15 locked on the suspension rope 16 via the moving pulley 36 and the constant pulley 38 is lowered. At this time, since the moving pulley 36 is used, the amount by which the suspension point 15 is lowered is twice the amount of movement of the rod 42. This means that the stroke of the rod 42 is reduced by half, which contributes to the downsizing of the cylinder 34 and thus the actuator 22 and the suspension balance 20. If a further pulley is additionally provided, the stroke of the rod can be reduced to ４, and the actuator 2 and the suspension balance can be further reduced in size. The gas spring 40 serves as a shock absorber for alleviating the sudden movement of the rod 42.
[0016]
The throttle valve 52 is closed when the hanging point 15 is lowered by a desired size. Then, the flow of the hydraulic oil stops, the operation of the rod 42 stops, and the lowering operation of the suspension point 15 also stops. In the cylinder 34, the volume by which the rod 42 is pushed is reduced. The reduced amount of hydraulic oil is absorbed by the accumulator 54 provided in the oil pipe 50 of the closed circuit, and the accumulator 54 expands at the hydraulic oil accommodating portion as shown by the two-dot chain line in FIG. When the load of the suspended load 14 is released from the rod 42, the hydraulic pressure on the head side 46 becomes equal to that on the rod side 48. Then, the hydraulic oil that has expanded the accumulator 54 by the action pressure from the compressed gas portion of the accumulator 54 starts to return to the head side 46 via the check valve 56, and the rod 42 causes frictional resistance between the piston 35 and the inner wall of the cylinder 34. It is pushed out of the cylinder 34 against the force and returns to the right end of the rod side 48.
[0017]
A control box 60 for controlling the operation of the throttle valve 52 provided on each actuator 22 is attached to the hanging balance 20, and a remote controller 62 for remote control is connected to the control box 60. The hand controller 62 is operated by an operator who monitors the lifting status. The operator removes the lifting state by repeating the lowering operation of the hanging point 15 several times while checking the lifting state of the suspended load 14 by the crane 18 using the hand operation device 62. As a result, the plurality of suspension points 15 of the suspended load 14 come up almost simultaneously at the time of the ground cut, and safe lifting can be performed.
[0018]
As described above, according to the hanging balance 20 of the present embodiment, the hanging point 15 of the hanging load 14 is used only when necessary by a simple operation of opening the throttle valve 52 using the load of the hanging load 14 connected to the rod 42. Can be lowered. When the throttle valve 52 is closed, the lowering of the suspension point 15 can be stopped immediately. When the load of the suspended load 14 is released from the rod 42, the rod 42 automatically returns to the right end on the rod side 48 by the action pressure of the accumulator 54. As described above, since the accumulator 54 has the automatic return function of the rod 42, it is not necessary to provide a special return mechanism. For this reason, the hanging balance 20 of the present embodiment does not need to be equipped with a complicated hydraulic control system including a hydraulic pump system and various switching valves, and can reduce costs and simplify the hydraulic control system.
[0019]
Further, since the suspension balance 20 is formed by fixing the plurality of actuators 22 each containing the hydraulic cylinder 34 in the casing 24 in a horizontal state, the structure is compact. For this reason, there is a special operation and effect that a hanging allowance can be increased compared to a conventional suspension frame in which a plurality of hydraulic cylinders are hung. Further, since the sudden movement of the rod 42 is reduced by the gas spring 40, the operation of the hanging balance 20 can be performed safely.
[0020]
FIG. 5 is a schematic perspective view of a hanging balance 20A according to a second embodiment of the present invention. In the present embodiment, the front and rear ends of the same four actuators 22 as those described in the first embodiment are joined at right angles to each other to form a horizontal and rectangular suspension frame as a whole. At each corner of the suspension frame, a suspension rope 16 from each actuator 22 hangs. Horizontal members 70, 70 for connecting the corners in a diagonal direction are wrapped around the suspension frame portion, and suspension metal fittings 72 for engaging with a crane (not shown) are provided at the center intersection position. The hanging balance 20A according to the second embodiment also has the same advantageous effects as those of the first embodiment, and has a special advantage that a large allowance can be obtained.
[0021]
FIG. 6 is a schematic diagram of a hanging balance 20B according to a third embodiment of the present invention. A plurality of (e.g., two to four) actuators 82 are swingably suspended from the suspension frame 80. Compared with the actuator 22 according to the first embodiment, the actuator 82 does not include the constant pulley 38 in the casing, and a guide roller 84 for guiding the suspension rope 16 is provided at the lower end instead of the constant pulley 38. . Other configurations of the actuator 82 are substantially the same as those of the actuator 22 according to the first embodiment, and a description thereof will be omitted. The hanging balance 20B of the third embodiment also has the same operation and effect as those of the first embodiment.
[0022]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the suspension balance which concerns on this invention, by using the load of the several hydraulic cylinders provided in plurality by the load of a suspended load, only when needed by the simple operation which opens and closes the throttle valve attached to each hydraulic cylinder, the suspended load Can be lowered or the lowering can be stopped. When the load of the suspended load is released from the rod, the rod automatically returns to the original position by the action pressure of the accumulator. For this reason, the hanging balance according to the present invention does not need to be equipped with a complicated hydraulic control system including a hydraulic pump system and various switching valves, and can reduce costs and simplify the hydraulic control system. Further, since the suspension balance is formed by fixing a plurality of actuators accommodating the hydraulic cylinders in a horizontal state to each other, there is an extraordinary effect that the allowance for the suspension can be increased.
[Brief description of the drawings]
FIG. 1 is a partially cut-away side view of a suspension balance 20 according to a first embodiment of the present invention.
FIG. 2 is a partially cutaway plan view of the hanging balance 20 according to the first embodiment of the present invention.
FIG. 3 is a perspective view of the hanging balance for a first embodiment of the present invention;
FIG. 4 is an explanatory diagram of an actuator according to the first embodiment of the present invention.
FIG. 5 is a schematic perspective view of a hanging balance 20A according to a second embodiment of the present invention.
FIG. 6 is a schematic diagram of a hanging balance 20B according to a third embodiment of the present invention.
FIG. 7 is a perspective view showing an example of a hanging balance according to the related art.
[Explanation of symbols]
12 Carrying bed, 14 Hanging load, 15 Hanging point, 16, 16A, 16B, 16C, 16D Hanging rope, 18 Crane, 20, 20A, 20B Hanging Balance, 22, 22A, 22B, 22C, 22D ... Actuator, 24 ... Casing, 34 ... (Hydraulic) cylinder, 36 ... Moving pulley, 38 ... Constant pulley, 40 ... Gas Spring, rod, rod, head side, rod side, oil pipe, oil pipe, throttle valve, accumulator, check valve, check valve, 60 Control box, 62 Hand-operated device.

Claims (3)

In a suspension balance having a plurality of hydraulic cylinders and configured to hang a load at multiple points, each of the hydraulic cylinders has a head side and a rod side connected to each other via a closed circuit oil pipe, and a throttle valve is connected to the oil pipe. An accumulator is provided, wherein the load of the suspended load acts in a direction of pushing the rod of each of the hydraulic cylinders into the cylinder. The suspension balance according to claim 1, wherein a plurality of actuators each containing the hydraulic cylinders housed in a casing are formed for each hydraulic cylinder, and the plurality of actuators are fixed to each other in a horizontal state. The suspension balance according to claim 1 or 2, wherein a gas spring is connected to a rod of each of the hydraulic cylinders.

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