Buffer straddle crane for cargo container handling operations

Details Buffer straddle crane for cargo container handling operations Buffer straddle crane for cargo container handling operations

2001-12-11

2003-11-25

Brahan, Thomas J. (Department: 3652)

Material or article handling

Marine loading or unloading system

Marine vessel to/from shore

C212S325000, C414S141300

Reexamination Certificate

active

06652211

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a supplemental apparatus for cargo container handling gantry cranes and, more particularly, it relates to a device for improving the efficiency of the cycle time for dockside quay cranes. Specifically, it relates to a buffer crane which operates in conjunction with cargo container handling gantry cranes.
2. Description of the Prior Art
The utilization of various types of cargo container handling gantry cranes or quay cranes for the purpose of increasing the speed of loading and unloading of cargo container transport ships is well-established in the prior art. However, despite the numerous designs, structures, and forms disclosed by the prior art, which have been developed for the accomplishment of the specific objectives, purposes, and requirements of cargo container handling, the devices and apparatus which have heretofore been devised and utilized consist basically of familiar, expected, and obvious configurations, combinations, and arrangements of well-known machinery. This will become apparent from the following consideration of the closest known and relevant prior art.
Shipping companies wish to reduce the time a ship spends in port involved in berthing operations in order to increase the efficiency of each vessel. Increasing the productivity of berthing operations allows ships to be loaded and unloaded faster, thereby effectively reducing the ship's down time. Efforts are continuously being made to further this objective. The present invention is a significant advancement in these efforts.
Reference is made to
FIG. 1
of the drawings which shows a typical dockside berthing operation for a ship. The primary container handling equipment is comprised of one or more quay cranes
11
which extend outboard from the dock's edge
13
across the beam of a ship
15
. Cargo containers
17
which have been unloaded or are to be loaded are temporarily stored in a stacking yard
19
proximate to the ship's loading berths. The berthing operations under specific consideration involve the transport of containers between a container ship and the stacking yard.
In ship unloading operations, quay cranes
11
access the shipboard cargo containers from above the ship and move them to the ground level or dockside cargo container transporters
21
such as chassis trucks, trailer trucks, or automatically guided vehicles (AGVs). The transporters deliver the containers to the stacking yard
19
where other vehicles or cranes
23
transfer the containers to stacks. In loading operations, quay cranes lift the cargo containers from the dockside container transporters and move them to the ship where they are lowered into shipboard cells. The berthing operations involve three separate types of sub-operations: (1) quay crane handling; (2) transport between the crane and the stacking yard; and (3) storage yard manipulation.
Quay cranes in the form of cargo container handling gantry cranes are arranged to extend over a longitudinal expanse and transfer cargo containers horizontally from one deposition area to another. The largest of such gantry cranes are primarily located dockside in shipping ports around the world as well as in railroad yards. Quay cranes generally have either a horizontal sliding boom or a cantilever boom, the latter of which can usually be raised by rotating it around its inboard end. Long span yard and quay cranes are typically supported by vertical structures located inboard from the ends of the crane gantry on rail mounted wheels. The present invention can be utilized with any of these basic types of crane designs and operations.
Reference is made to
FIG. 2
of the drawings which illustrate a typical cantilever boom type quay crane
11
having a buffer crane
25
of the present invention positioned thereunder. The quay crane cantilevered rotatable boom
27
is supported by the crane superstructure
29
mounted on crane truck wheels
31
which run on dock rails which are disposed parallel to the edge
13
of the harbor dock. The crane superstructure supports a horizontal gantry
33
disposed generally mid-height thereon at an elevated location above the cargo container pickup and deposition areas
35
. The gantry is supported from below by the main legs of the superstructure.
In the cantilevered rotatable boom design for quay cranes, sheaves are disposed at the pinnacle
37
of the superstructure of the crane to guide wire rope reeving
39
which is used to lift the outboard or cantilevered end of the boom to the upright raised stowed position. The wire rope reeving raises the cantilevered boom by rotating it about its hinge point
43
at its inboard end proximate to the superstructure.
While, in most typical dockside applications, the gantry of a cargo container handling quay crane is a slidable or a raisable cantilevered boom extending from a crane superstructure to project over a ship, other types of large gantry yard cranes supported at both ends are located in large cargo container storage or transfer areas. All of these cranes are similar to the gantry type crane of
FIG. 2
in that they employ a movable trolley
45
, usually with a suspended operator's cab
47
, which shuffles along the gantry
33
and boom
27
suspending a cargo container lifting spreader
49
. The spreader can be raised or lowered from the crane gantry by the operator and engages from above the top of cargo containers
17
. The containers are carried by a transporter
21
or are stacked on the dock or shipboard to permit them to be lifted by the trolley for horizontal transport. During loading, the containers are lifted from the transporter and are moved outboard along the gantry to where they are lowered into the cells
51
in a cargo container transport ship. During unloading, the containers are lifted from the cells and moved from shipboard to shore where they are lowered onto the transporters.
The cargo container lift trolley
45
, mounted on rails on the crane gantry sections
27
,
33
, can traverse from one end of the gantry to the other with a suspended container. The cargo container lifting spreader
49
is suspended from the trolley by fleet through wire rope reeving through a detachable headblock which carries the wire rope suspension sheaves. Different or variable length spreaders can be secured to the headblock to accommodate correspondingly different size containers.
There are two highly interdependent berthing sub-operations: (1) quay crane handling; and (2) transport vehicle movements between the crane and the stacking yard. A delay in one of those sub-operations causes the other to pause and idle which reduces the overall productivity of the entire system. Several factors can cause delays in the two berthing sub-operations including: (1) unsteady or irregular quay crane operations; (2) the time required for effecting interbox connector (IBC) installation and removal processes; (3) delays in stacking yard operations that delay throughput of transport vehicles; (4) the time required for quay cranes performing alignment of containers with transport chassis; (5) congestion of transport vehicles under quay cranes; and (6) various other factors such as machinery operator mistakes or inexperience.
Quay crane container handling rates are measured in cycle rates. Unsteady quay crane operations result because the cranes move containers different distances depending upon the location of the container on a ship varying the cycle rates. For example, as a quay crane loads or unloads each column of containers spaced across the beam of the ship, the hoist travels a longer distance outboard for each successive column of containers and lowers and hoists longer for each container located deeper in the stack. The increased traveling distance and stationary time for the hoist, for each successive container, adds to the container handling time and the resulting cycle time.
Unsteady quay crane operation, coupled with a constant number of transport vehicles allotted per crane, creates inefficiencies in th

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