Traversing hoists – Having means to prevent or dampen load oscillations – Antisway
Reexamination Certificate
1999-08-05
2002-05-07
Brahan, Thomas J. (Department: 3652)
Traversing hoists
Having means to prevent or dampen load oscillations
Antisway
C212S312000, C212S323000, C212S324000, C212S327000
Reexamination Certificate
active
06382437
ABSTRACT:
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/JP98/05448 which has an International filing date of Dec. 3, 1998 which designated the United States of America.
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to a crane system which has a wire rope stretched from a frame of a body to a hoisting accessory, and which pays out the wire rope from a drum or winds the wire rope around the drum to carry a load transversely, or move it up or down.
2. Related Art
A crane system for carrying a container (load) is present in a place such as a container yard at a port. The crane system is used to unload containers from a vehicle or the like and stack them on the container yard, or load containers from the container yard into a vehicle or the like.
FIG. 1
shows an example of a gantry crane system which has existed so far. This type of crane system has a pair of gate-shaped body frames, i.e., front and rear body frames
101
. The crane system includes a plurality of traveling wheels
103
provided at a lower end of each of legs
101
a
for supporting a transverse girder
101
b
of each of the body frames
101
, and traction motors
102
for driving the traveling wheels
103
. The traction motor
102
rotationally drives the traveling wheels
103
, thereby moving the body frames
101
in a front-and-back direction (a direction along the front and the back of the body frames
101
disposed at the front and at the back, respectively; the same will hold hereinbelow).
On the front and rear transverse girders
101
b
of these body frames
101
, rails
104
are laid. The front and rear rails
104
and
104
as a pair are spanned by a traversing trolley
105
, which is supported on the rails laterally movably.
On the traversing trolley
105
, a takeup drum
106
is borne. The takeup drum
106
is wound with a plurality of wire ropes
107
for suspending a load, and a hoisting accessory
108
is suspended via these plural wire ropes
107
. A container C as a suspended load is attached to the hoisting accessory
108
.
The conventional crane system of the foregoing constitution carries the container C in the following manner: As shown in
FIG. 2
as well, with the body frames
101
at a halt, the hoisting accessory
108
is lowered, and the container C is attached to the hoisting accessory
108
. Then, the takeup drum
106
is driven to wind the wire ropes
107
, thereby moving the hoisting accessory
108
upward. As a result, the container C is raised and suspended. Then, the traversing trolley
105
is moved in a traversing direction (a direction of an arrow A in
FIG. 2
in which a traversing motion is made rightward or leftward on the gate-shaped body frames
101
; the same will hold hereinbelow) along the rails
104
, whereby the container C is moved to a predetermined position.
Once the container C arrives at the predetermined position, the traversing trolley
10
S is stopped. In this state, the wire ropes
107
are paid out by driving the takeup drum
106
to move the hoisting accessory
108
vertically downward (in a direction of an arrow C in FIG.
2
), thereby lowering the container C. The container C is placed at a predetermined position as shown by a two-dot chain line in FIG.
2
.
With this conventional crane system, it is necessary to provide the rails
104
on the transverse girders
101
b
of the body frames
101
, and install the traversing trolley
105
on these rails
104
. In this case, there is need to consider the weight of the rails
104
, the weight of the traversing trolley
105
, and the weight of the container C imposed on the hoisting accessory
108
. Thus, not only the transverse girders
101
b
, but also the entire crane system must have great rigidity and large weight.
In the crane system illustrated in
FIG. 1
, consider that with the container C being held by the hoisting accessory
108
, the traversing trolley
105
is moved laterally (horizontally) along the rails
104
, and stopped at a predetermined position. In this case, sway in a direction of an arrow B in
FIG. 2
occurs in the hoisting accessory
108
and the container C owing to the inertial force of the traversing trolley
105
moving in the lateral direction. This sway often does not settle quickly.
Actually, therefore, the traversing trolley
105
is moved at a low speed so that no sway occurs in the hoisting accessory
108
and the container C when the traversing trolley
105
is stopped. If such sway takes place, the operator waits until settlement of the sway, and then the wire ropes
107
are paid out from the takeup drum
106
to lower the container C.
This practice of moving the traversing trolley
105
at a low speed, or resuming operation after waiting until settlement of the sway of the hoisting accessory
108
and the container C, takes a long time for operation, thus deteriorating the operating efficiency.
There may be a case in which a load handling operation is performed on a floor FL inclined to drain rainwater or the like, as shown in FIG.
3
. In this case, with the crane system of
FIG. 1
, the body frames
101
become inclined according to the slope of the floor FL. Nevertheless, the hoisting accessory
108
and the container C, attached to the traversing trolley
105
via the plurality of wire ropes
107
, are suspended vertically, in other words, obliquely relative to the floor FL, by their own weight.
Then, it is attempted to lower and place the container C at a predetermined position indicated by a two-dot chain line in FIG.
3
. However, the container C held by the hoisting accessory
108
may touch a container C nearby, depending on the number of containers C stacked or the distance between the adjacent stacks of containers C. This may make it difficult to place the suspended container C exactly at the predetermined position.
FIG. 4
shows a wire rope crane at a port, proposed by the applicant, for loading onto a ship or unloading from a ship onto the land. This crane system in
FIG. 4
has a relay yard
120
for the efficient carriage of a container C. Between the relay yard
120
and a floor FL of a container yard, wire ropes
122
stretched between a hoisting accessory
108
and hoists
121
, which are disposed at upper right and upper left positions, are extended and contracted. By this measure, the container C is carried between the relay yard
120
and the floor FL. There is a disclosure that the rightward and leftward wire ropes
122
are connected to the hoisting accessory
108
at its one or two (including another in the depth direction) connection points P.
This proposal shown in
FIG. 4
has a structure in which the hoisting accessory
108
is suspended by the wires
121
from obliquely upward sites. This structure permits anti-sway of the portion
122
corresponding to the wire rope up to the connection point P in the aforementioned crane system shown in
FIGS. 1
to
3
. Thus, the hoisting accessory
108
and the container C may be prevented from swaying, and drawbacks due to the aforesaid low-speed movement or lengthy time until settle of sway may be diminished.
For the rope crane of
FIG. 4
, the relevant structure has been disclosed, but there have been no disclosures of problems encountered during actual operation, such as the weight and rigidity of the crane, control for each of the delivery and winding of the wire
122
, and difficulty with the placement of a container on the slope of the floor FL. What has been disclosed is only the crane system using the wires
122
.
SUMMARY OF THE INVENTION
The present invention has been accomplished in light of the foregoing problems. An object of the invention is to provide a crane system in which wire ropes are pulled obliquely upwardly to suspend a hoisting accessory, and wire rope actions for traversing and hoisting/lowering of the hoisting accessory are coordinated for actual operation.
It is another object of the invention to provide a crane system of a downsized, simplified structure which has diminished the great rigidity and heavy weight of a
Abiru Hisanori
Chikura Takashi
Hirano Tatsuya
Ichikizaki Tetsuo
Masumoto Masanori
Brahan Thomas J.
Mitsubishi Heavy Industries Ltd.
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