JPH0466496A - Device for preventing swing of container crane - Google Patents

Abstract

PURPOSE:To sufficiently damp swing of a container loaded with freight by shaking a sheave bracket by means of tensile force change of a wire rope, and extending/ contracting a damper cylinder connected to the sheave bracket. CONSTITUTION:Assuming that a container 7 is swayed in the direction of the arrow by inertia, tension indicated by the arrows (a) and (b) works on wire ropes 15a and 15b, sheave brackets 20A and 20B are turned anticlockwise, and a piston rod 30 is pressed in the direction of the arrow. The operating fluid in an oil chamber B being compressed is pushed out to flow to a tank 43 through a damper valve 42a, wherein generating damping force. The operating fluid from the tank 43 is drawn into an oil chamber A. When the piston rod 30 is moved in the direction of the arrow, the operating fluid in an oil chamber D flows into a pressurizing tank 54 smoothly. If a damping motion stops, free pistons 34 and 35 are pushed back by the pressure of the pressurizing tank 54 until they about on a stopper 36. A piston 32 is returned to a neutral position precisely, cylinders 26A and 26B are also returned to the neutral position to prepare for the next damping action.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for preventing swinging due to inertia, wind pressure, etc. when a container crane is traveling.

(Prior Art) -A large container crane is constructed as shown in FIG.

A boom 3 is suspended horizontally on a crane main body 2 that runs along a rail 1 installed on the ground.
The trolley 4 travels along.

The trolley 4 is driven by a drive operation of a winch installed in a machine room 5, and a container 7 suspended from the trolley 4 by a wire 6 is moved in the direction of the arrow in the figure or in the opposite direction.

After stopping at a predetermined position, the wire 6 is extended to allow the container 7 to land.

(Problems to be Solved by the Invention) By the way, in this crane, when the cargo etc. loaded on the container 7 is moved and then arrives at a predetermined position, the container 7 suspended via the wire 6 is Shaking occurs due to internal inertia, and if this continues indefinitely, it becomes difficult to work efficiently and safely.

For this reason, for example, some systems control the running speed of the trolley 4 and gradually decelerate it without suddenly stopping, thereby minimizing the swinging of the container 7 in the running direction of the trolley 4. Regarding external forces such as wind pressure, speed control of the trolley 4 has no effect, and work efficiency under strong winds is significantly reduced.

The present invention aims to solve such problems.

(Means for Solving the Problems) Therefore, the present invention provides a container crane in which a container is suspended from a movable trolley via a wire rope, one end of the wire rope is fixed, and the other end is linked to a hoisting winch. The container is suspended and supported by at least two wire ropes at front and back positions in the running direction of the trolley,
The middle of these two wire ropes is routed around two sheaves attached to a rotatable sheave bracket, a damper cylinder is connected to the sheave bracket, and a predetermined damping force is applied to the expansion and contraction of the damper cylinder. Hydraulic oil is supplied and discharged through a damper circuit, and the damper cylinder exerts a damping effect on the movement of the sheave bracket that swings in response to changes in the tension of the two wire ropes.

(Function) Therefore, when the container suspended from the trolley swings in the running direction of the trolley, the tension of the front and rear wire ropes changes accordingly.

The sheave bracket swings due to changes in the tension of the wire rope, and the damper cylinder connected to it expands and contracts. Since the movement of the damper cylinder is damped by the hydraulic oil from the damper circuit, the shaking of the container loaded with cargo can be efficiently damped and suppressed.

(Example) An example of the present invention shown in FIGS. 1 and 2 will be described.

FIG. 1 schematically shows a part of the trolley 4. The trolley 4 has two pairs of guide sheaves 10a, 10b, lla, and llb located on both sides of the trolley 4 at the front and rear, respectively.
) is attached to the container 7 below the trolley 4,
Similarly, guide sheaves 12a and 12b are provided at the front and rear of both sides, and two wire ropes are provided respectively], 5g, 1
5b is multiplied.

Each end of the wire ropes 15a, 15b is wound around a hoisting drum 16 of a winch, and the container 7 is raised or lowered by winding up or down rotation of the hoisting drum 16.

Note that the center (other end) of each wire rope 15a, 15b is connected to a center guide 17L17 fixed to the crane body side.
They are each bonded to b.

Further, a pair of left and right sheave brackets 2OA and 20B are provided, and a pair of sheaves 21a and 21L+ are disposed on the sheave brackets 2OA and 20B, respectively, and the wire rows 115g and 1
5b is multiplied by 1.

Sheave brackets 2OA and 20B each have wire ropes 15
Rotation shafts 22a, 22b according to changes in tension of a, 15b.
The container swings like a parallel link around the trolley 4, thereby absorbing the shaking of the container 7 suspended from the trolley 4.

And the arm 25 of each sheave bracket 2OA, 20B
Damper cylinders 26A and 26B are installed in order to damp the rocking motion of the sheave brackets 2OA and 20B, respectively.
The base ends of the damper cylinders 26A and 26B are symmetrically connected to the swing bracket 27.

The swing bracket 27 is attached to each sheave bracket 2°A, 2
Rotating motion parallel to 0B.

The sheave brackets 2OA, 20B and the swing bracket 27 are attached to appropriate positions on the crane body (see FIG. 3).

As shown in FIG. 2, each damper cylinder 26A, 26B has a damper piston 31 and a neutral return piston 32 coupled to a piston rod 30.
Oil chambers A and B are formed on the left and right sides of the oil chambers A and B, which are partitioned by a partition wall 33, and the neutral return piston 32 is sandwiched between free pistons 34 and 35 that are interposed in the oil chambers C and D. Note that the free pistons 34 and 35 restrict the center position of the neutral return piston 32 by coming into contact with the stopper 36.

Damper circuits 40A and 40B are configured to supply and discharge hydraulic oil to oil chambers A and B of each damper cylinder 26A and 26B to perform damping operation of the damper piston 31, and also supply hydraulic oil to oil chambers C and D. A neutral return circuit 50 is provided which returns the neutral return piston 32 to neutral by supplying and discharging it.

Each damper circuit 40A and 40B includes a damping force switching valve 41, a damping valve 42a42b with different high and low set pressures, a hydraulic oil tank 43, and a check valve that selectively communicates each circuit depending on the pressure. 44a, 44b and 45a, 45b, the hydraulic oil from the oil chamber A or B on the high pressure side is released to the tank 43 via the damping valve 42a or 42b, and the oil chamber B or A on the low pressure side is connected to the tank 43. Allows hydraulic oil to be sucked in without resistance.

The neutral return circuit 50 includes a speed control circuit 53a consisting of a parallel circuit of a throttle valve 51a and a check valve 52a;
1b and a check valve 52b (two sets of speed control circuits 53a and 53b each), a pressurized hydraulic oil tank (accumulator) 54, a speed control circuit consisting of a throttle valve 55g and a check valve 55b. 55, oil chamber C
Pressure of hydraulic oil is applied to and D to move the neutral return piston 32 to the neutral position via the free screws 34 and 35.

The system is constructed as described above, and its operation will be explained next.

The L-lorry 4 is driven by a drive device (not shown), and the container 7 suspended from it via wire ropes 15a, 5b also moves together.

At this time, the switching valves 41 of the damper circuits 40A and 40B are in the neutral position (block position), and the damper cylinder 26A
, 26B are locked, the damper cylinders 26A, 26B cannot expand or contract at all, and the sheave brackets 2OA, 20B do not rotate either.

Note that while the trolley 4 is running, the wire ropes 15a and 15b that are wrapped around the trolley 4 and the container 7 cannot be wrapped around the trolley 4 and the container 7 because the hoisting drum 16, center guides 17a, 17b, etc. are fixed to the crane body. The effective lengths of the wire ropes 15a, 15b do not change, so the container 7 does not go down by 1''.

When the trolley 4 approaches the target position and starts decelerating, the switching valve 41 is switched to either the high damping or low damping position by a signal from a control device (not shown), and the damping valve 4 is switched to the high damping or low damping position.
2a and 42b communicate with oil chambers A or B of damper cylinders 26A, 26B via check valves 44a or 44b.

One damping valve 42a has a large throttling resistance, and the other damping valve 42b has a small throttling resistance, and either one is selected depending on the shaking condition of the container 7 loaded with cargo.

When the L-lorry 4 approaches a stop and, for example, the container 7 swings in the direction of the arrow due to inertia, tension as shown by arrows a and b acts on the wire ropes 15a and 15b, causing the wire ropes 15a and 15b to The equilibrium state is disrupted, and the sheave brackets 2OA and 20B tend to rotate counterclockwise in the figure.

Therefore, the piston rods 30 of the damper cylinders 26A, 26B are pressed in the direction of the arrow.

Then, the compressed hydraulic oil in the oil chamber B is pushed out and flows to the tank 43 via the check valve 44b, the switching valve 41, and the damping valve 42a, and at this time, a damping force is generated according to the throttle resistance.

On the other hand, hydraulic oil is sucked into the oil chamber A which expands at this time from the tank 43 via the check valve 45a.

When the container 7 is swung back in the opposite direction, resistance is applied to the hydraulic oil flowing out from the oil chamber A in the opposite direction to the above, and in this way, the damper cylinder Resistance acts during the reciprocating stroke of 26A326B, damping this oscillation and quickly suppressing the sway of the cargo.

On the other hand, free pistons 34 and 35 are interposed on both sides of the neutral return piston 32, and define oil chambers C and D.

Therefore, when the piston rod 30 moves in the direction of the arrow, the neutral return piston 32 moves to the free piston 3 in the oil chamber.
Move while pressing 5, and check the hydraulic oil in the oil chamber by checking the check valve 52b.
, 55b and flows into the pressurized tank 54 without resistance. Furthermore, when the piston rod 30 moves in the opposite direction, the hydraulic oil flows from the oil chamber C into the tank 54 without resistance.

Therefore, the movement of the damper cylinders 26A, 26B is not inhibited.

When the damping motion by the damper cylinders 26A and 26B stops, the free pistons 34 and 35 move to the stopper 3.
6, the neutral return piston 32 sandwiched between them returns to the neutral position accurately, and the damper cylinder 26A returns to the neutral position.
, 26 B can also return to the neutral position, loaf position, and prepare for the next damping action.

Note that the free piston 34, 35 is returned to its original state using the throttle valve 51.
a, 5l b, 55a, etc., so it is done slowly, and the damper cylinders 26A, 2 in the same direction
The damping effect of 6B is not impaired.

Then, the container 7 is lowered to a predetermined position by rotating the hoisting drum 16 at the stop position of the L-rolley 4 and letting out the wire ropes 5a and 15b.

In this way, the shaking of the container 7 loaded with cargo is effectively attenuated, so that the container 7 can be quickly stopped at the stop position of the trolley 4, and the loading operation can be carried out safely and efficiently.

In addition, this damping effect of the container 7 can be activated in the same way even when the container 7 is shaken by strong winds, etc., and the container 7 that has been stirred by the wind can be quickly brought to a standstill, thereby improving the safety of work in strong winds. This will improve cargo handling and cargo arrival efficiency.

Incidentally, the damper circuits 40A, 40B that drive the damper cylinders 26A, 26B and the neutral return circuit 50 are integrated as an oil damper unit, so that the structure is reduced in size and the mounting structure to the aircraft body is simplified.

(Effects of the Invention) As described above, according to the present invention, the shaking of a container loaded with cargo is effectively attenuated, so the container can be quickly stopped at the stop position of the trolley, and the loading operation can be carried out safely. This action can be carried out efficiently, and this anti-swaying action of the container can also be used even when the container is shaken by strong winds, etc., and the container that has been stirred by the wind can be quickly brought to a standstill. This will improve work safety and cargo arrival efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a sectional view of a damper cylinder, and FIG. 3 is an explanatory diagram of a conventional device. 4...Trolley, 7...Container, 15a, 15b
...Wire rope, 16...Hoisting drum, 2OA,
20B02. Sheep bracket, 26A, 26B...
Damper cylinder, 4OA, 40B...damper circuit, neutral return circuit 50°

Claims (1)

[Claims] 1. A container crane in which a container is suspended from a movable trolley via a wire rope, one end of the wire rope is fixed, and the other end is linked to a hoisting winch,
The container is suspended and supported by at least two wire ropes at front and back positions in the running direction of the trolley, and the middle of these two wire ropes is hung around two sheaves attached to a rotatable sheave bracket. A damper cylinder is connected to the damper cylinder, and hydraulic oil is supplied and discharged to the damper cylinder through a damper circuit that applies a predetermined damping force to the expansion and contraction of the damper cylinder, and the damper cylinder swings in response to changes in the tension of the two wire ropes. A steady rest device for a container crane, characterized in that it is configured so that a damping action of a damper cylinder is applied to the movement of a sheave bracket. 2. A damper piston and a neutral return piston are coupled to the piston rod of the damper cylinder, and hydraulic oil is supplied and discharged to the left and right oil chambers of the damper piston via the damper circuit, while the neutral return piston 2. The steady rest device for a container crane according to claim 1, wherein pressurized hydraulic oil from a neutral return circuit is introduced into the oil chambers on both sides of the two free pistons sandwiching the free piston.