Traversing hoists – Having means to prevent or dampen load oscillations – Antisway
Reexamination Certificate
2000-07-31
2001-05-22
Olszewski, Robert P. (Department: 3652)
Traversing hoists
Having means to prevent or dampen load oscillations
Antisway
C212S273000, C212S312000, C212S272000
Reexamination Certificate
active
06234332
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART STATEMENT
1. Field of the Invention
The present invention relates to a swaying hoisted load-piece damping control apparatus, and more detailedly relates to a swaying hoisted load-piece damping control apparatus for a load-piece hoisting device used in a large-scale load-piece lifting container crane and the like.
2. Description of the Prior Art
FIG. 6
shows an overall configuration of a swaying hoisted load-piece damping apparatus for use in a conventional container crane and
FIG. 7
shows operating states of the conventional swaying hoisted load-piece damping apparatus.
As shown in
FIG. 6
, a transverse trolley
11
is provided transversally movable (movable in the side-to-side directions in
FIG. 6
on main crane girder
29
. The transverse trolley
11
has a pair of rails
12
and
13
thereon which guide a pair of sheave blocks
14
and
15
, respectively so that the sheave blocks
14
and
15
can move within short range in parallel with the moving direction of the transverse trolley
11
. The transverse trolley
11
is connected through a wire
16
to a trolley driver
17
disposed on the main girder (not shown) on which the transverse trolley
11
moves. The sheave blocks
14
and
15
have respective sheave block drivers
18
and
19
for driving the sheave blocks
14
and
15
. A hoisting attachment
22
is hanged from the transverse trolley
11
through winding wires
20
. This hoisting attachment
22
hoists a container
23
as a hoisted load-piece. Here, as shown in
FIG. 6
, the hoisting attachment
22
has a detecting mark
21
for detecting the sway of the hoisted load-piece on the upper surface thereof.
In stopping the sway of such a load-piece hoisting device, the operator in the operator cab, visually observing the motion of the hoisting attachment
22
, used to perform manual remote-control operations in the following manner.
That is, in the state shown in
FIG. 6
, when the trolley drivers
17
drives the transverse trolley
11
from the left to the right in a direction shown by an arrow a, if the movement of the transverse trolley
11
is changed from the constant-speed transverse travel mode to the retarding travel mode, the hoisted load-piece
23
hanged by the hoisting attachment
22
sways rightward (forward) due to its inertia, as indicated by an arrow &bgr; in FIG.
7
(
a
). At that moment, as the operator in the operator cab watches the detecting mark
21
on the hoisting attachment
22
and perceives the sway, the operator controls the transverse trolley
11
to accelerate as indicated by an arrow &agr; in FIG.
7
(
b
), in conformity with the transverse sway of the hoisted load-piece
23
(in the aforementioned direction of the arrow &agr;). Alternatively, the two sheave blocks
14
,
15
may be controlled to move in the same direction with the swaying direction of the hoisted load-piece
23
by activating the left and right sheave block drivers
18
,
19
on the transverse trolley
11
. Thereafter, the operator tries to control the transverse trolley
11
to retard in time with the reverse motion of the hoisted load-piece
23
after the trolley completes a rightward (forward)-swing of a certain magnitude or should control the sheave blocks
14
,
15
to move in the opposite direction to the aforementioned direction so that the transversally swinging load-piece is dampened to stop.
In the case shown in
FIG. 6
, if, for example, the hoisted load-piece
23
slues clockwise causing skew sway on a plane as indicated by arrows A, the operator again perceives it from the movement of the detecting mark
21
and activates the driver
18
,
19
so as to move the sheave block
15
leftward (in the direction shown by an arrow B) and the other sheave block
14
rightward (in the direction shown by an arrow C) in synchronism with the skew sway. To deal with a repulsive swing of the hoisted load-piece
23
, the sheave blocks
14
,
15
may and should be driven in the opposite directions to those described above, so that the skew sway is attenuated to stop.
The conventional, swaying hoisted load-piece damping apparatus in which sway is manually stopped by the operator, however, suffers from problems as follows.
That is, as stated above, it is true that simple transverse sway or simple skew sway of the hoisted load-piece
23
can be attenuated and stopped by the operator by accelerating and/or retarding the transverse trolley
11
or by moving the sheave blocks
14
,
15
in synchronism with the swinging state of the hoisting attachment
22
. But, if transverse sway and skew sway occur at the same time and cause the hoisted load-piece
23
to make a complex motion, it becomes difficult or practically impossible for the operator to manually drive the transverse trolley
11
or the sheave blocks
14
,
15
well enough to deal with the situation.
As soon as the hoisted load-piece
23
is stopped to sway, the sheave blocks must normally be returned by force to their home positions or the middle of the transverse trolley
11
with respect to the transverse direction, so that the two (left and right) sheaves
14
and
15
can move in either transverse direction to prepare for a next swing of the hoisted load-piece
23
. In order to improve the efficiency of conveying the hoisted load-piece
23
, the transverse trolley
11
must be driven at a maximum speed during it travels transversally. When the hoisted load-piece
23
comes near a target position where it is to be unloaded onto the ground, the transverse trolley
11
should be retarded so as to stop at the target position and then need be stopped at the target position where the load-piece is unloaded. To sum up, it is necessary to effect, all at once, position control of the sheave blocks
14
and
15
, velocity and/or position control of the transverse trolley
11
in conformity with the transverse position and conditions, other than the control of damping the swaying hoisted load-piece
23
. Nevertheless, since the conventional sway-damping operation is manually effected by the operator, the controlling operation requires the toughest techniques for even the skilled operators.
3. Object and Summary of the Invention
The present invention has been achieved to solve the above problems and it is therefore an object of the present invention to provide a swaying hoisted load-piece damping control apparatus which simplifies the operation of damping swaying hoisted load-piece and is able to achieve the damping operation in an assured manner.
Another object of the present invention is to provide a swaying hoisted load-piece damping control apparatus which is able to realize an optimal control for damping and stopping a swaying hoisted load-piece as fast as possible by automating the complicated swaying hoisted load-piece damping operation.
A further object of the present invention is to provide a swaying hoisted load-piece damping control apparatus which is able to improve the work efficiency of conveying hoisted load-pieces by markedly reducing the work amount of the operator and the time required for sway damping.
In order to attain the above objects, a swaying hoisted load-piece damping control apparatus (an apparatus defined in claim
1
) for use in a load-piece hoisting device having a transverse trolley for hoisting a load-piece being transversally movable on a crane girder and the driver thereof, and a pair of, or right and left, sheave blocks which are disposed along moving directions of said transverse trolley in parallel with the sides of said transverse trolley and movable relative to said transverse trolley and the drivers thereof, comprises: trolley displacement/velocity detectors for detecting a displacement and a velocity of said transverse trolley; sway detectors for detecting the displacement and velocity of a sway on right and left sides of the load-piece hoisted by said transverse trolley; sheave-block displacement/velocity detectors for detecting the displacement and velocity of said right and left sheave blocks; a notch disposed on an operation controlling pa
Kouno Susumu
Miyata Noriaki
Monzen Tadaaki
Okubo Yoshiaki
Toyohara Takashi
Johnson R. B.
Mitsubishi Jukogyo Kabushiki Kaisha
Olszewski Robert P.
Trop Pruner & Hu P.C.
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