Hoist

Details Hoist Hoist

2000-01-10

2003-10-14

Matecki, Kathy (Department: 3652)

Traversing hoists

Having means to prevent or dampen load oscillations

C212S271000, C212S273000, C254S344000

Reexamination Certificate

active

06631816

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a hoist used in a container crane.
FIG. 1
shows a container crane and
FIG. 2
illustrates a boom derrick, a head block lifter and a trolley traverser used in the container crane. More specifically, the container crane comprises land- and seaward rails Q
1
and Q
2
on a quay P at harbor S, a traveler
2
with legs
1
a
and
1
b
running on the rails Q
1
and Q
2
, a girder
3
substantially horizontally mounted on a top of the traveler
2
, a boom
4
pivoted to a tip of the girder
3
so as to be swung upward, a main trolley
5
traversing along the girder
3
and boom
4
, a head block
6
suspended from and vertically movable relative to the trolley
5
, a spreader
7
mounted on the block
6
and with which a container C is to be locked, a first catenary trolley
19
positioned closer to a base end of the girder
3
than the main trolley
5
and traversing along the girder
3
and boom
4
and a second catenary trolley
20
positioned closer to the tip of the boom
4
than the main trolley
5
and traversing along the girder
3
and boom
4
.
In the container crane as described above, unloading of the container C from a ship V to the quay P and loading of the same from the quay P to the ship V are carried out in combination of operations such as motion of the traveler
2
along the quay P, traverse of the trolley
5
on the girder
3
and boom
4
, vertical motion of the block
6
relative to the trolley
5
and locking of the container C by the spreader
7
.
Disposed on the girder
3
is a machine room
8
with a drum
11
for derricking motion of the boom
4
, drums
15
a
and
15
b
for vertical motion of the block
6
, a drum
13
for traverse of the main trolley
5
and drums
9
a
and
9
b
for traverse of the catenary trolleys
19
and
20
.
Rotation of the drum
11
in normal and reverse directions causes a boom-derricking rope
12
to be wound and unwound, respectively, resulting in change of angle of the boom
4
to the girder
3
.
Rotation of the drums
15
a
and
15
b
in normal and reverse directions causes block-lifting ropes
16
a
and
16
b
to be wound and unwound, respectively, resulting in vertical motion of the block
6
relative to the trolley
5
.
Rotation of the drum
13
in normal and reverse directions causes trolley-traversing ropes
14
a
and
14
b
to be wound and unwound, resulting in traverse of the trolley
5
towards the base and tip ends of the boom
4
, respectively, since the rope
14
a
is locked at its opposite ends to the drum
13
and engaged at its intermediate portion with the trolley
5
via the base end of the girder
3
and the rope
14
b
is locked at its opposite ends to the drum
13
and engaged at its intermediate portion with the trolley
5
via the tip of the boom
4
.
Rotation of the drums
9
a
and
9
b
in normal.and reverse directions causes trolley-traversing ropes
10
a
and
10
b
to be wound and unwound, resulting in traverse of the trolleys
19
and
20
towards the base and tip ends of the boom
4
, respectively, since the rope
10
a
is locked at its opposite ends to the drums
9
a
and
9
b
and engaged at its intermediate portion with the trolley
19
via the base end of the girder
3
and the rope
10
b
is locked at its opposite ends to the drums
9
a
and
9
b
and engaged at its intermediate portion with the trolley
20
via the tip of the boom
4
and since the trolleys
19
and
20
are interconnected through a rope
17
.
The catenary-trolley drums
9
a
and
9
b
are adapted to be rotated in synchronization with rotation of the main-trolley drum
13
. The first catenary trolley
19
follows after the main trolley
5
so as to be positioned intermediately between the base end of the girder
3
and the trolley
5
. The second catenary trolley
20
follows after the main trolley
5
so as to be positioned intermediately between the tip end of the boom
4
and the trolley
5
.
The catenary trolleys
19
and
20
have rollers (not shown) pivoted to the trolleys
19
and
20
to support the main-trolley-traversing ropes
14
a
and
14
b
from below, respectively. The roller pivoted to the trolley
19
serves to suppress any excessive loosening of the rope
14
a
between the base end of the girder
3
and the trolley
5
. The roller pivoted to the trolley
20
serves to suppress any excessive loosening of the rope
14
b
between the tip of the boom
4
and the trolley
5
.
In recent years, there is a trend of increased traverse distance of the main trolley
5
as well as increased lift of the head block
6
in such container crane in association with a tendency of building larger-sized ships V.
In the conventional container crane, however, the block-lifting ropes
16
a
and
16
b
are wound on sheaves
18
pivotally supported at four corners of the block
6
to have eight turns in total so as to suspend the block
6
from the trolley
5
. Therefore, increased traverse distance of the main trolley
5
and/or increased lift of the head block
6
will lead to prolongation of the block-lifting ropes
16
a
and
16
b
and increase in size of the block-lifting drums
15
a
and
15
b
. This may disadvantageously result in increase in weight of the system above the traveler
2
and/or difficulties in maintenance and inspection of the ropes
16
a
and
16
b.
The present invention was made to solve the above problems and has its major object to provide a hoist which is light in weight and compact in size.
BRIEF SUMMARY OF THE INVENTION
According to a hoist of the invention drums with independent drive sources are mounted on a trolley and an unwound end of the head-block-lifting rope wound around each of the drums is locked on a suspension piece of a container, which suppress any need of the ropes in longer length and the drums in larger size.
According to a hoist of the invention sun gears, carriers and planetary gears in each of the drums as well as internal teeth in each of the drums for integral rotation with the drum provide a speed reducing mechanism for transmitting rotation of the drive source to the drum, which contributes to make the entire hoist compact in size.
According to a hoist of the invention provided between two drums is a differential gear mechanism for transmitting rotation of drums to an output shaft. Rotation of a drive shaft of the differential gear mechanism may be suppressed to synchronize rotation of the two drums.
According to a hoist of the invention provided between two drums is a differential gear mechanism for transmitting rotation of the two drums to an output shaft. The drive shaft of the differential gear mechanism is rotated to vary rotation of the two drums relatively to each other.
According to a hoist of the invention when the trolley is to be accelerated, a link is displaced in position in a predetermined direction by an actuator. The positional displacement of the link is transmitted to two paired drums via torque arms so that the drums positioned,ahead in the moving direction of the trolley are rotated in rope-winding direction and the drums positioned behind in the moving direction of the trolley are rotated in rope-unwinding direction. As a result, tensions on the ropes at positions ahead and behind in the moving direction of the trolley are adjusted to apply a force directed in the moving direction of the trolley on the suspension piece.
When the trolley is to be decelerated, the link is displaced in position in a direction opposite to the direction during the acceleration. The positional displacement of the link is transmitted to the two paired drums via the torque arms. The drums positioned ahead in the moving direction of the trolley are rotated in rope-unwinding direction and the drums positioned behind in the moving direction of the trolley are rotated in rope-winding direction. As a result, tensions on the ropes positioned ahead and behind in the moving direction of the trolley are adjusted to apply a force directed in a direction opposite to the moving direction of the trolley on the suspension piece of th

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