Information
-
Patent Grant
-
6572325
-
Patent Number
6,572,325
-
Date Filed
Tuesday, March 23, 199925 years ago
-
Date Issued
Tuesday, June 3, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Walton; James E.
- Hill & Hunn LLP
-
CPC
-
US Classifications
Field of Search
US
- 403 410
- 220 15
- 220 4 F
- 108 561
- 214 105 R
- 414 7927
- 414 7929
- 294 683
-
International Classifications
-
Abstract
A freight container for use in intermodal freight transportation systems that includes lift castings having a top lift aperture located on the lift casting at an outboard position, such that when other containers are stacked on top of the container, loads are properly distributed through reinforcement beams of the container, thereby substantially reducing bending stresses in the container, substantially reducing the possibility fatigue failure of the container, and reducing the costs of maintenance and inspection of the container.
Description
BACKGROUND ART
1. Field of the Invention
The present invention relates generally large freight containers used in intermodal freight transportation systems, in which the freight containers are stacked upon each other and transported by truck, rail, ship, and combinations thereof. In particular, the present invention relates to a freight container having an improved lift casting that are compatible with existing lift mechanisms and existing freight containers.
2. Description of Related Art
Large freight containers used in intermodal freight transportation systems are well known in the art. The intermodal freight transportation industry has always been very competitive. As with most competitive industries, any technological innovation that provides a competitive advantage is highly sought after. Thus, there is an ever-present need for faster, better, safer, and cheaper methods of transporting goods, both domestically and internationally.
In an effort to achieve maximum strength at minimum weight, these large freight containers are typically made of steel frames and aluminum skins. Load-bearing steel reinforcement beams are integrated into the exterior of the container in the walls, ceiling, and floor at certain industry-recognized locations along the lengths of the containers. These reinforcement beams provide the necessary strength to allow the freight containers to be lifted and stacked on top of each other. The reinforcement beams are comprised of side posts integrated into the container walls, headers integrated into the container ceilings, and footers integrated into the container floors. The headers are connected to the side posts at “lift” castings. The footers are connected to the side posts at “stack” castings. Unfortunately, due to height restrictions and strength requirements, lift castings and stack castings must protrude into the interior of the container. This intrusion not only reduces the available storage volume of the container, but makes it difficult to load the container, as well. Operators must maneuver cargo around these intrusions to prevent damaging the cargo or the castings. This is costly both in the amount of cargo that can be shipped, and in the additional time required to load a container.
Individual lift castings and stack castings usually have apertures on both their tops and their sides that allow the container to be lifted by conventional lift mechanisms, or cranes. The lift mechanisms lift, move, and stack the containers on top of each other between the different modes of transportation. These lift mechanisms have hydraulically actuated arms and lift attachments that are adapted to spread to the appropriate width and attach to the container through either the side apertures or the top apertures in the lift castings. The apertures in the stack castings are aligned with the apertures in the lift castings so that the containers can be coupled together by standard inter-box connectors (“IBC's”).
Over the years, the desire to pack increased volumes of freight into a container has led to an evolutionary increase in the length and width of freight containers. Due to certain height restrictions in the transportation of containers over land and rail, such as the clearance height of bridges and tunnels, the overall height of the containers has generally remained unchanged. However, containers have increased from a length of 40′ and width of 96″ to lengths as long as 53′ and widths as wide as 102″. Although larger containers are able to hold a greater volume of freight, significant structural problems arise when larger containers are used in conjunction with smaller containers in the overall intermodal transportation system.
For example, when all of the containers in an intermodal transportation system are of the same size, one container can be stacked on top of other containers, and the reinforcement beams of the containers remain aligned. Thus, the load of the upper container is transmitted through the stack casting of the upper container, through the inter-box connector, through the lift casting of the lower container and down to the stack casting of the lower container to the stacking surface. On the other hand, when larger containers are used with smaller containers, the reinforcement beams and castings of the larger container do not align with the reinforcement beams and castings of the smaller container. This offset creates undesirable bending moments and bending stresses in the reinforcement beams and castings of both containers, thereby causing the reinforcement beams and castings on the containers to buckle and fail under the bending loads. In addition, because prolonged vibration of stacked containers in intermodal transportation often leads to fatigue failure of the reinforcement beams, constant and expensive container maintenance and inspection programs are required.
A number of efforts have been made to alleviate this problem. For example, intrusive support braces have been added to the lift castings, additional reinforcement plates have been added to the exterior of the containers adjacent to the lift castings, and additional mounting apertures have been added to the stack castings. Some containers have lift castings that do not allow other containers to be stacked on top of the container at all.
With these increases in container size, it has been necessary to modify the design of lift castings and stack castings, as well. However, due to the long life of these freight containers, and the large number of older containers currently in service, it is inevitable that new containers will be used in intermodal transportation systems with existing containers. Thus, it is desirable that newly designed containers include lift castings and stack castings that align with the lift castings and stack castings of older containers, thereby making new containers backward compatible with older containers.
Despite the above-mentioned advances in the art, there is a need for an improved freight container for use in intermodal freight transportation systems that has lift castings in which a top lift aperture is located at an outboard position, so that when other containers are stacked on top of the improved container, the load is properly distributed through reinforcement beams of the improved container.
There is also a need for an improved lift casting for use on freight containers, the improved lift casting having a top lift aperture that is located at an outboard position.
In addition, there is a need for an improved bayonet-type twist lock mechanism for use on freight container lift mechanisms, the bayonet-type twist lock having a shorter tapered point that extends into the lift casting a shorter distance than existing bayonet-type twist locks.
Also, there is a need for an improved method of lifting and transporting freight containers.
BRIEF SUMMARY OF THE INVENTION
Because the prior art does not meet the needs of the intermodal freight transportation industry, it is an objective of the present invention to provide an improved freight container for use in intermodal freight transportation systems that includes lift castings having a top lift aperture located on the lift casting at an outboard position, such that when other containers are stacked on top of the improved container, loads are properly distributed through reinforcement beams of the improved container.
It is another objective of the present invention to provide an improved lift casting for use on freight containers, the improved lift casting having a top lift aperture that is located at an outboard position of the lift casting.
It is another objective of the present invention to provide an improved lift casting for use on freight containers, the improved lift casting being of shorter height, thereby creating less intrusion into the interior of the container.
It is another objective of the present invention to provide an improved freight container having lift castings that substantially reduce bending stresses in reinforcement beams of the improved container, thereby preventing failure of the improved container due to the bending stresses.
It is another objective of the present invention to provide an improved freight container having lift castings that substantially reduce fatigue stresses in reinforcement beams of the improved container, thereby preventing failure of the improved container due to the fatigue stresses.
It is another objective of the present invention to provide an improved bayonet-type twist lock mechanism for use on freight-container lift mechanisms, the bayonet-type twist lock having a shorter tapered point, that extends into the lift casting a shorter distance than existing bayonet-type twist locks, thereby allowing the use of lift castings having shorter heights.
It is another objective of the present invention to provide an improved method of lifting and transporting freight containers.
It is another objective of the present invention to provide a method of substantially reducing bending stresses in freight containers.
It is another objective of the present invention to provide a method of preventing fatigue failure in freight containers.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-1E
are perspective views of intermodal containers that illustrate an evolution of intermodal freight containers from a conventional International Standard Organization (“ISO”) container through a container according to the present invention.
FIG. 2
is a perspective view of a conventional freight container stacked on top of a container according to the present invention, both containers being stacked on a railway flat car.
FIGS. 3A-3C
are perspective views of a conventional IBC.
FIG. 4
is a cross-sectional view of the IBC of
FIGS. 3A-3C
connecting two containers wherein the two containers have lift castings and stack castings in accordance with the invention.
FIGS. 5A-5E
are perspective views of lift castings and corresponding stack castings that illustrate an evolution of lift castings and stack castings for containers from a conventional ISO container through a container according to the present invention.
FIGS. 6A-6D
are various views of the lift casting according to the present invention.
FIG. 7
is a perspective view illustrating the relative differences in size between a conventional lift casting and stack castings, and the lift casting and stack casting according to the present invention.
FIGS. 8A-8E
are perspective views illustrating various stacking combinations in which the container according to the present invention is stacked with both similar containers and conventional containers.
FIGS. 9A and 9B
are perspective views illustrating a limited number of stacking combinations in which the container according to the present invention cannot be stacked with conventional containers.
FIGS. 10A and 10B
are views of a prior-art lift mechanism having a bayonet-type twist lock member.
FIG. 11
is a perspective view of a bayonet-type lift mechanism according to an alternate embodiment of the present invention.
FIGS. 12A-12C
are progressive perspective views of the lift mechanism of
FIG. 11
engaging the lift casting according to the present invention.
FIG. 13
is a perspective view illustrating ground stacking of prior-art containers.
FIG. 14
is a perspective view illustrating ground stacking of containers according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to
FIGS. 1A-1E
in the drawings, a plurality of prior-art intermodal freight containers
11
,
13
,
15
,
17
, and
19
are illustrated. Intermodal freight container
21
is illustrative of the preferred embodiment of the present invention. Containers
13
,
15
,
17
,
19
, and
21
represent an evolution in intermodal freight container technology. Although containers
13
,
15
,
17
,
19
, and
21
are generally all of the same height h, containers
13
,
15
,
17
,
19
, and
21
may be classified by their differing lengths and widths. For example, container
13
represents a conventional ISO container having a length
1
1
of 40′ and a width w
1
of 96″; container
15
represents a conventional “domestic” container having a length
1
2
of 48′ and a width w
2
of 102″; container
17
represents a conventional container, typical of containers used by the J. B. Hunt Company, having a length
1
3
of 53′ and a width w
3
of 102″; and container
19
represents another typical J.B. Hunt container having a length
1
4
of 48′ and a width w
4
of 102″. Container
21
represents a the preferred embodiment of the present invention, and has a length
1
5
, preferably of about 48′, and a width w
5
, preferably of about 102″. Hereinafter, containers having a width of 96″ will be referred to as “standard” width containers; and containers having a width of 102″ will be referred to as “wide” containers. Containers
13
,
15
,
17
,
19
, and
21
all include conventional locking doors for loading freight.
Containers
13
,
15
,
17
, and
19
are typically constructed of steel support frames and aluminum skins. In container
13
, a plurality of reinforcement beams, each consisting of a header
13
a
, two side posts
13
b
, and a footer
13
c
, were added around each end of container
13
to provide added strength for lifting and stacking container
13
. A lift casting
13
d
, integrated into the reinforcement beam, was located at each joint of header
13
a
and side posts
13
b
. Likewise, a stack casting
13
e
, integrated into the reinforcement beam, was located at each joint of side posts
13
b
and footer
13
c
. Lift castings
13
d
and stack castings
13
e
will be discussed in more detail below. The remaining prior-art containers
15
,
17
, and
19
each contain similar reinforcement beams having headers
15
a
,
17
a
, and
19
a
; side posts
15
b
,
17
b
and
19
b
; footers
15
c
,
17
c
, and
19
c
; lift castings
15
d
,
17
d
, and
19
d
; and stack castings
15
e
,
17
e
, and
19
e.
All prior-art containers
13
,
15
,
17
, and
19
are adapted in various ways to be lifted by conventional lift mechanisms (see FIGS.
10
A and
10
B). Lift castings
13
d
,
15
d
, and
19
d
include apertures (see
FIG. 5
) in their top surfaces that allow the respective containers to be grasped and lifted from the top by lift attachments, usually bayonet-type twist lock members, of the lift mechanisms. However, lift casting
17
d
only has an aperture (see
FIG. 5
) in its side surface; therefore container
17
must be lifted from the side by lift attachments that are adapted with inwardly protruding lift pins (see FIG.
10
A). These lift mechanisms and lift attachments will be discussed in more detail below.
Continuing with reference to
FIG. 1
, container
21
is preferably constructed of a steel frame and a thin aluminum skin. Container
21
includes a plurality of reinforcement beams, each consisting of a header
21
a
, two side posts
21
b
, and a footer
21
c
(see FIG.
7
). Headers
21
a
, side posts
21
b
, and the footers
21
c
surround container
21
to provide added strength for lifting and stacking container
21
. A lift casting
21
d
, integrated into the reinforcement beam, is located at each joint of header
21
a
and side posts
21
b
. Likewise, a stack casting
21
e
, integrated into the reinforcement beam, is located at each joint of side posts
21
b
and footer
21
c
. Lift casting
21
d
and stack casting
21
e
will be explained in more detail below.
As is shown, the reinforcement beams of container
13
are located at the ends of container
13
. Thus, the reinforcement beams are separated by a distance of about 40′. It should be noted, that although the overall length of freight containers has varied over the years, the distance between the reinforcement beams has remained constant at about 40′. Thus, the distance between the reinforcement beams on containers
15
,
17
, and
19
is about 40′. One reason for maintaining this spacing is so that the load-bearing reinforcement beams of newer containers align with the load-bearing reinforcement beams of older containers. Another reason for maintaining a common distance between reinforcement beams is that the lift castings
13
d
,
15
d
,
17
d
,
19
d
, and
21
d
remain equally spaced apart, and the lift mechanisms do not require modification or reprogramming. For these reasons, it is preferable that the distance between the reinforcement beams of container
21
is also about 40′.
As the length of freight containers grew beyond 40′, it became necessary to add additional reinforcement adjacent to the lift castings to prevent container failure due to the longitudinal bending moment and bending stresses about the lift castings due to the added weight at the end of each container. For example, containers
17
and
19
include reinforcement plates
17
f
and
19
f
, respectively, to provide added strength against such failure. In a similar fashion, it is preferable that container
21
include reinforcement plates
21
f.
Referring now to
FIG. 2
in the drawings, prior-art container
17
is shown stacked on top of container
21
of the present invention. Containers
17
and
21
are shown loaded on a conventional railroad flatcar
23
used in conventional intermodal transportation systems. Although container
17
has lift castings
17
d
that do not allow other containers to be stacked on top of container
17
, container
21
is adapted to allow container
17
to be stacked on top of container
21
. The desired alignment of the reinforcement beams of the two containers
17
and
21
is illustrated. As explained above, the reinforcement beams consist of headers
17
a
and
21
a
, side posts
17
b
and
21
b
, footers
17
c
and
21
c
, lift castings
17
d
and
21
d
, stack castings
17
e
and
21
e
, and reinforcement plates
17
f
and
21
f
. This alignment is desired so that the load of container
17
is properly carried by the reinforcement beams of container
21
, not by the container skins of container
21
.
When the load of container
17
is not properly distributed over the reinforcement beams of container
21
, there is a possibility that container
21
will be damaged or will fail. As is shown, although the lengths of container
17
and container
21
are different, the widths are the same, about 102″. In conventional intermodal transportation systems, it is desirable to stack containers of the same width on top of each other. If the upper container is not as wide as the lower container, undesirable bending moments are created about the lower lift castings, resulting in possible failures of the lower container, usually in the headers, the lift castings, or both. On the other hand, if the upper container is wider than the lower container, undesirable bending moments are created about the upper stack castings, resulting in possible failures of the upper container, usually in the footers, the stack castings, or both.
Referring now to
FIGS. 3A-3C
and
4
in the drawings, a conventional twist-lock IBC
25
is illustrated.
FIGS. 3A-3C
illustrate the twist-lock function of IBC
25
, and
FIG. 4
is a cross-sectional view of IBC
25
in a locked position interconnecting, for example, two containers
21
, one on top of the other. Twist-lock IBC's
25
, are necessary in conventional intermodal transportation systems to prevent shifting of the containers when the containers are stacked upon each other. IBC
25
includes a housing
27
, a central shaft
29
having a top portion
29
a
and a bottom portion
29
b
, and a handle
31
connected to shaft
29
for pivoting top portion
29
a
and bottom portion
29
b
between a locked position and an unlocked position.
In operation, before an upper container is stacked on top of a lower container, an IBC
25
is placed in the top aperture of each lift casting of the lower container. The upper container is then lowered down on top of the IBC's
25
. Often it is necessary for an operator to reach between the containers to align the IBC's
25
, a potentially dangerous task. Thus, for safety reasons, it is desirable that IBC
25
be located as far outboard on containers
21
as possible to minimize the distance that an operator must reach between the containers. As will be explained below, this safety feature is provided by container
21
. Once the upper container has been successfully lowered onto IBC's
25
, the operator manually twist-locks the IBC's
25
by rotating handle
29
. It is preferable that IBC
25
be as close in line with side posts
21
b
as possible, as indicated by line of force F. This ensures that the load of upper container
21
is transferred through stack casting
21
e
, through IBC
25
, through lift casting
21
d
, to lower container
21
, thereby minimizing bending stresses in the reinforcement beams. In addition, the use of IBC's
25
in conjunction with containers
21
according to the present invention reduces the chance of introducing undesirable bending moments and bending stresses in the reinforcement beams of containers
21
. Although the operation of IBC
25
is entirely conventional, it is mentioned here because its operation is made more effective and safer by use of container
21
and the stacking methods according to the present invention.
Referring now to
FIGS. 5A-5E
in the drawings, lift castings
13
d
,
15
d
,
17
d
,
19
d
, and
21
d
of
FIG. 1A-1E
are illustrated in enlarged fashion with their corresponding stack castings
13
e
,
15
e
,
17
e
,
19
e
, and
21
e
. Lift casting
13
d
has an elongated top aperture
13
g
and an elongated side aperture
13
h
. Stack casting
13
e
has an elongated bottom aperture
13
i
and an elongated side aperture
13
j
. Lift casting
15
d
has an elongated top aperture
15
g
and an elongated side aperture
15
h
. Stack casting
15
e
has an elongated bottom aperture
15
i
and an elongated side aperture
15
j
. Lift casting
17
d
has only an upwardly pointed triangular side aperture
17
h
, which necessitates lifting from the side, and prevents other containers from being stacked on top of container
17
, because there would be no aperture in which to lock IBC
25
. Stack casting
17
e
has an elongated inboard bottom aperture
17
i
, an elongated outboard bottom aperture
17
j
, and a circular side aperture
17
k
. This dual aperture arrangement on stack casting
17
e
allows container
17
to be stacked on both standard width and wide containers.
Lift casting
19
d
has an elongated top aperture
19
g
and an upwardly pointing triangular side aperture
19
h
, which allows lifting from either the top or the side, and allows standard width containers to be stacked on top of container
19
. However, it is important to note that top aperture
19
g
is located inboard on lift casting
19
d
near the joint of lift casting
19
d
and header
19
a
, such that top aperture
19
g
aligns with the bottom apertures of standard width containers, such as container
13
, not wide containers. As will be explained below, container
21
of the present invention addresses this shortcoming. Stack casting
19
e
has an elongated inboard bottom aperture
19
i
, an elongated outboard bottom aperture
19
j
, and a circular side aperture
19
k
. Lift casting
21
d
of the present invention has an elongated top aperture
21
g
and a downwardly pointing triangular side aperture
21
h
. Stack casting
21
e
of the present invention has an elongated inboard bottom aperture
21
i
, an elongated outboard bottom aperture
21
j
, and a circular side aperture
21
k
. The purpose of elongated top apertures
13
g
,
15
g
,
19
g
, and
21
g
is to allow a bayonet-type twist lock member of a lift attachment on a lift mechanism (see
FIGS. 10A and 10B
) to be inserted into the elongated apertures
13
g
,
15
g
,
19
g
, and
21
g
and rotated 90° into a locked position, thereby allowing the container to be lifted.
Each successive pair of castings includes improved features over its predecessor. Lift casting
13
d
and stack casting
13
e
provided a simple means of stacking standard width containers
13
, as long as the containers were exactly the same. Lift casting
15
d
and stack casting
15
e
allowed wide containers
15
to be stacked with standard width containers
13
. This is why top aperture
15
g
and bottom aperture
15
i
are moved closer to the inboard edges of lift casting
15
d
and stack casting
15
e
. Due to the extra width of container
15
, lift castings
15
d
and stack castings
15
e
had to be larger so as to extent farther inboard to align with the standard width container
13
. In addition, it was necessary to add additional support members
15
k
. Support members
15
k
were bulkier and added an undesirable additional intrusion into the interior of container
15
. When stacking containers
15
upon each other, the inboard location of top apertures
15
g
and bottom apertures
15
i
created undesirable bending stresses in the reinforcement beams of containers
15
.
Lift castings
17
d
have no top aperture; therefore containers
17
must be lifted at side apertures
17
h
by lift mechanisms that have inwardly protruding lift pins
77
(see FIGS.
10
A and
10
B). In addition, lift castings
17
d
do not provide the necessary top apertures to receive IBC
25
. Thus, no containers can be stacked on top of container
17
. However, inboard bottom aperture
17
i
and outboard bottom aperture
17
j
allow container
17
to be stacked on top of either a wide container with an inboard top aperture, such as container
15
, or a standard width container, such as container
13
. With respect to lift casting
19
d
, upwardly pointing triangular side aperture
19
h
is identical in form and function as side aperture
17
h
. However, lift casting
19
d
includes a top aperture
19
g
that allows container
19
to be lifted from the top by a bayonet-type twist lock member of a lift mechanism (see FIGS.
10
A and
10
B). Stack castings
19
e
are identical in form and function as stack castings
17
e.
It should be noted that top aperture
19
g
is located near the inboard edge of lift casting
19
d
. Although this allows standard width containers, such as container
13
, to be stacked on top of container
19
, the inboard location of top aperture
19
g
means that the load of the upper container transferred through IBC
25
is not properly aligned with the load bearing side posts
19
b
of container
19
. Thus, undesirable bending stresses are created. In addition, even when stacking containers
19
upon each other, the inboard location of top apertures
19
g
and inboard bottom apertures
19
i
create the same bending stress problems in the reinforcement beams of containers
19
.
On the other hand, these problems are solved by improved container
21
, lift casting
21
d
, and stack casting
21
e
. Although stack casting
21
e
is very similar in form and function to stack castings
17
e
and
19
e
, top aperture
21
g
of lift casting
21
e
is located on lift casting
21
d
such that top aperture
21
g
is in an outboard position on container
21
. This relocation of top aperture
21
g
to an outboard position aligns the load from wide containers stacked on top of container
21
along line of force F (see FIG.
4
), thereby substantially reducing bending moments and bending stresses in container
21
. For the same reason, this relocation of top aperture
21
g
to an outboard position substantially reduces fatigue stress, thereby preventing fatigue failure, extending the useful life, and reducing the cost of maintenance and inspection of container
21
.
Referring now to
FIGS. 6A-6D
in the drawings, the preferred embodiment of lift casting
21
d
of the present invention is illustrated. It is important to note that elongated top aperture
21
g
is located at an outboard position, such that its vertical outboard surface
42
is substantially coplanar, i.e., very close to being in the same plane with, the interior surface of the side post
21
b
, as is shown by reference line Z, not at an inboard position as are top apertures
13
g
,
15
g
, and
19
g
of the prior-art lift castings
13
d
,
15
d
, and
19
d
, respectively. For this reason, lift casting
21
d
substantially reduces the undesirable bending stresses created when stacking prior-art containers. Lift casting
21
d
includes a bevel
41
that aids in the insertion of the bayonet-type twist lock member
74
of lift mechanism
71
(see
FIG. 10B
) into lift casting
21
d
. As is best seen in
FIG. 60
, downwardly pointing triangular side aperture
21
h
is located such that a top edge
43
is flush with an inside surface
45
of a top plate
47
. This arrangement ensures clearance of a tab portion
74
a
(see
FIG. 10B
) of bayonet-type twist lock member
74
as it rotates 90° into its locked position. It should be understood that side aperture
21
h
may be of other geometrical shapes, including an upwardly pointing triangle. Top aperture
21
g
and side aperture
21
h
allow lift casting
21
d
to have a shorter height, or profile P, than prior-art lift castings. Therefore, lift casting
21
d
makes less of an intrusion into the interior of container
21
, thereby providing more storage volume and reducing the time and maneuvering required to load container
21
.
Referring now to
FIG. 7
in the drawings, lift casting
21
d
and stack casting
21
e
of the present invention are illustrated in a side-by-side comparison with prior-art lift casting
15
d
and stack casting
15
e
. The lower edge of header
15
a
is generally flush with the interior of container
15
, and the upper edge of footer
15
c
is generally flush with the interior of container
15
. Likewise, the lower edge of header
21
a
is generally flush with the interior of container
21
, and the upper edge of footer
21
c
is generally flush with the interior of container
21
. As is shown, lift casting
21
d
and stack casting
21
e
require a much smaller intrusion into the interior of container
21
than lift casting
15
d
, with its necessary support member
15
k
, and stack casting
15
e
into the interior of container
15
. As is shown, top aperture
15
g
is located in an inboard position close to the intersection of lift casting
15
d
and header
15
a
. Because top aperture
21
g
of lift casting
21
d
is located at an outboard position, container
21
may be stacked in a larger number of container combinations, without creating undesirable bending stresses.
Referring now to
FIGS. 8A-8E
in the drawings, a variety of container stacking combinations is illustrated. Lift casting
21
d
and stack casting
21
e
allow container
21
to be stacked in a large number of stacking combinations involving a variety of prior-art containers. For example, a first combination
51
includes container
21
stacked on top of an identical container
21
. A second combination
53
includes container
21
stacked on top of equal length, wide container
19
. A third combination
55
includes container
21
stacked on top of a shorter, standard-width container
13
. A fourth combination
57
includes container
21
stacked on top of equal length, wide container
15
. A fifth combination
59
includes wide container
19
stacked on top of equal length container
21
. In combination
59
, container
19
may be replaced by container
17
that is the same width as container
21
, but that is longer than container
21
. It should be understood that these examples are to illustrate the wide variety of stacking combinations that are permitted by the present invention. These examples are not intended to limit the number of stacking combinations in which container
21
may be utilized.
Referring now to
FIGS. 9A and 9B
in the drawings, a variety of container stacking combinations that are not available when using container
21
are illustrated. Although lift casting
21
d
and stack casting
21
e
allow container
21
to be stacked in a large number of stacking combinations involving a variety of prior-art containers, a small number of combinations are not available due to container interconnection incompatibilities. For example, in a first excluded combination
61
, a standard width container
13
cannot be stacked on top of container
21
. In a second excluded combination
63
, container
15
cannot be stacked on top of container
21
. It should be understood that there may be other stacking combinations that are not possible due to container interconnection incompatibilities. The stacking combinations illustrated in
FIGS. 9A and 9B
are not possible.
Referring now to
FIGS. 10A and 10B
in the drawings, a conventional hydraulic twist-lock lift mechanism
71
for lifting and moving freight containers is illustrated. Lift mechanism
71
has four lifting attachments
73
, each having a bayonet-type twist lock member
74
. Lifting attachments
73
are located at the end of extensible arms
75
, that are adjustable in the direction of arrows A to accommodate containers of varying widths, or containers that must be lifted from side apertures, such as container
17
described above. In order to lift containers from the side, each lift attachment
73
is equipped with an inwardly extending lift pin
77
. Lift pins
77
may be retractable to allow for additional clearance between the container and lift attachment
73
. Lift mechanism
71
generally has transverse booms
79
and
81
to carry extensible arms
75
. The distance between booms
79
and
81
is generally adjustable, although the length between lift castings on containers has been standardized at about 40′.
Bayonet-type twist lock member
74
of lift attachment
73
is best seen in FIG.
10
B. As is shown, lift attachment
73
includes a housing
91
having a lower collar
93
. Collar
93
has an elongated shape that corresponds with elongated top apertures
13
g
,
15
g
,
19
g
, and
21
g
. In addition, collar
93
has a height c that generally corresponds with the thickness of top apertures
13
g
,
15
g
,
19
g
, and
21
g
. Housing
91
houses a rotatable shaft
94
and means (not shown) for actuating rotatable shaft
94
. Bayonet-type twist lock member
74
is coupled to rotatable shaft
94
. Bayonet-type twist lock member
74
includes a tab portion
74
a
and a tapered portion
74
b
that tapers to a point over a vertical distance d.
In operation, to lift container
19
, lift attachments
73
are aligned by an operator with top apertures
19
g
. Lift attachments
73
are then lowered such that bayonet-type twist lock members
74
are inserted through top apertures
19
g
in lift castings
19
d
. Once inserted, bayonet-type twist lock members
74
are rotated 90° by shaft
94
into a locked position, such that tab portions
74
a
are no longer aligned with elongated top apertures
19
g
. Once lift attachment is in the locked position, lift mechanism
71
can safely lift and transport container
19
. The vertical clearance inside the interior of lift casting
19
d
must be large enough to allow full insertion of tab portion
74
a
and tapered portion
74
b.
Referring now to
FIG. 11
in the drawings, an alternate embodiment of the present invention is illustrated. In this alternate embodiment, improved lifting attachments
73
′ replace lifting attachments
73
in lift mechanism
71
for lifting container
21
, or any other container with a short profile P (see FIGS.
6
A and
6
D). Each lift attachment
73
′ is equipped with an inwardly extending lift pin
77
′. Lift pins
77
′ may be retractable to allow for additional clearance between the container and lift attachment
73
′. Lift attachment
73
′ includes a bayonet-type twist lock member
74
′. As is shown, lift attachment
73
′ includes a housing
91
′ having a lower collar
93
′. Collar
93
′ has an elongated shape that corresponds with elongated top apertures
13
g
,
15
g
,
19
g
, and
21
g
. In addition, collar
93
′ has a height c′ that generally corresponds with the thickness of top apertures
13
g
,
15
g
,
19
g
, and
21
g
. Housing
91
′ houses a rotatable shaft
94
′ and means (not shown) for actuating rotatable shaft
94
′.
Bayonet-type twist lock member
74
′ is coupled to rotatable shaft
94
′. Bayonet-type twist lock member
74
′ includes a tab portion
74
a
′ and a tapered portion
74
b
′ that tapers to a point over a vertical distance d′. Lift attachment
73
′ is very similar in form and function to lift attachment
73
, with the exception that vertical distance d′ is slightly shorter than vertical distance d. This shorter distance d′ allows lift mechanism
73
′ to be used to lift containers having short profiles, such as profile P of container
21
. This, in turn, means that the lift castings intrude less into the interior of the containers, thereby providing more usable volume within the containers, and reducing the amount of maneuvering that an operator must perform while loading the containers. Although tab portion
74
a
′ is reduced in thickness, and tapered portion is reduced in height, bayonet-type twist lock member
74
′ retains sufficient strength to twist lock and lift containers at full capacity.
Referring now to
FIGS. 12A-12C
in the drawings, lift attachment
73
′ of the present invention is shown in progressive perspective views twist-locking onto lift casting
21
d
of the present invention. As is shown, after bayonet twist lock member
74
′ has been inserted through top aperture
21
g
, tab portion
74
a
′ and tapered portion
74
b
′ are rotated 90° by shaft
94
′. Once lift attachment
73
′ has twist-locked onto lift casting
21
d
, container
21
may be lifted and transported by a lift mechanisms, such as lift mechanism
71
. It is important to note that lift casting
21
d
may be used with existing conventional lift mechanisms and lift attachments, such as conventional lift attachment
73
in FIG.
10
B. In other words, lift casting
21
d
is dimensionally adapted for use with existing lift attachments
73
, and it is not necessary that distance d be shortened to accommodate lift casting
21
d
. The embodiment of the present invention shown in FIG.
11
and described above, allows lift casting
21
d
to have an even shorter profile P, thereby intruding less into the interior of container
21
.
Referring now to
FIG. 13
in the drawings, a plurality of containers
19
are shown stacked side-by-side. As explained above, containers
19
may be lifted from either top apertures
19
g
or side apertures
19
h
in lift castings
19
d
. As is shown, lift mechanism
71
is utilizing lift pins
77
to lift containers
19
from side apertures
19
h
. In order to place containers
19
side-by-side, it is necessary to leave a clearance x between each container
19
, clearance x being large enough for lift attachment
73
to pass therethrough as side pin
77
is being aligned with side aperture
19
h
. The disadvantages associated with such side-lifting and storing methods should be apparent, including: side lifting requires additional space x between containers
19
; clearance x provides little space for lift attachment
73
to pass through; and the operator's visibility, necessary to align side pin
77
with side apertures
19
h
, is greatly reduced, thereby increasing the possibility that container
19
will be damaged by lift mechanism
71
. It should be understood that containers
17
, which can only be lifted from side apertures
17
h
, present the same problems and disadvantages as containers
19
, when containers
19
are lifted from side apertures
19
h.
Referring now to
FIG. 14
in the drawings, a plurality of containers
21
according to the present invention are shown stacked side-by-side. Although containers
21
may be lifted from either top apertures
21
g
or side apertures
21
h
in lift castings
21
d
, it is preferred that containers
21
be lifted by top apertures
21
g
. As is shown, lift mechanism
71
is utilizing bayonet-type twist lock members
74
to lift containers
21
from top apertures
21
g
. Containers
21
may be placed side-by-side leaving only a minimal clearance x′ between each container
21
. Lift attachment
73
does not have to pass through clearance x′ to stack containers
21
side-by-side. Thus, the advantages associated with top-lifting and storing methods should be apparent, including: top lifting does not require additional space x between containers
21
; more containers
21
can be stored side-by-side than when using side-lifting methods; lift attachment
73
does not have to pass through clearance x′; and the operator's visibility is maximized, thereby reducing the possibility of damage to container
21
by lift mechanism
71
. It should be understood that the foregoing applies to all top-lift containers, such as containers
13
,
15
,
19
(when lifted from the top), and
21
.
It should be apparent from the foregoing that an invention having significant advantages has been provided. While the invention is shown in only one of its forms, it is not just limited but is susceptible to various changes and modifications without departing from the spirit thereof.
Claims
- 1. A freight container for use with an existing lift mechanism, the freight container comprising:a rigid support structure having a horizontal roof, vertical side walls, a horizontal floor, and at least one door; at least two reinforcement beams, each having a horizontal header coupled to the roof, a pair of vertical side posts coupled to the side walls, and a horizontal footer coupled to the floor, each side post having a transversely interior surface and an opposing transversely exterior surface; a stack casting disposed between each footer and each side post, the stack casting having a horizontal bottom plate and at least one stack aperture passing through the bottom plate, the stack aperture being adapted to allow stacking of the freight container; and a lift casting disposed between each header and each pair of side posts, each lift casting comprising: a horizontal upper plate; and at least one longitudinally elongated lift aperture through the upper plate, the elongated lift aperture being located in an outboard position on the upper plate that is a transverse distance from a center of the header such that an outboard elongated side wall of the elongated lift aperture formed in the upper plate is substantially vertically aligned with the transversely interior surface of each corresponding side post.
- 2. The freight container according to claim 1, wherein each lift casting further comprises:a vertical transversely outboard side plate; and a side lift aperture passing through the transversely outboard side plate.
- 3. The freight container according to claim 2, wherein each side lift aperture is generally triangularly shaped.
- 4. The freight container according to claim 3, wherein each generally triangularly shaped side lift aperture points downward.
- 5. The freight container according to claim 3, wherein each generally triangularly shaped side lift aperture points upward.
- 6. The freight container according to claim 4, wherein:each top plate of each lift casting has a selected thickness, thereby defining an upper surface and an interior surface; and wherein each generally triangularly shaped side lift aperture has a top edge that is flush with the interior surface to allow the lift mechanism to extend therethrough.
- 7. The freight container according to claim 5, wherein:each top plate of each lift casting has a selected thickness, thereby defining an upper surface and an interior surface; and wherein each generally triangularly shaped side lift aperture has a point that is flush with the interior surface to allow the lift mechanism to extend therethrough.
- 8. The freight container according to claim 1, wherein the lift casting further comprises:a bottom plate that is generally parallel to the upper plate, the bottom plate and the upper plate defining therebetween an internal clearance that is substantially the same as the height of a bayonet portion of the lift mechanism.
- 9. The freight container according to claim 8, wherein the lift casting is configured with a curved internal surface such that intrusion into the interior of the container is substantially eliminated.
- 10. The freight container according to claim 1, wherein the elongated lift apertures are substantially aligned with vertical lines of force acting through the side posts, such that bending stresses in the freight container are substantially reduced.
- 11. The freight container according to claim 1, wherein the elongated lift apertures are aligned with vertical lines of force acting through the side posts, such that fatigue stresses in the freight container are substantially reduced.
- 12. The freight container according to claim 10, wherein the lines of force are created by stacking a first freight container on top of a second freight container, such that the stack castings of the first container are coupled to the lift castings of the second container.
- 13. The freight container according to claim 11, wherein the lines of force are created by stacking a first freight container on top of a second freight container, such that the stack castings of the first container are coupled to the lift castings of the second container.
- 14. The freight container according to claim 11, wherein the freight container is at least 102 inches wide and the elongated lift apertures are at least 96 inches apart, such that the freight container may be interlockingly stacked in combination with any freight container having lift and stack apertures 96 inches apart.
- 15. The freight container according to claim 11, wherein the freight container is about 102 inches wide and the transversely outboard stack apertures are about 96 inches apart, such that the freight container may be interlockingly stacked in combination with any freight container having lift and stack apertures 96 inches apart.
- 16. Amended) The freight container according to claim 1, wherein the locations of the at least one stack aperture and the at least one elongated lift aperture allow the freight container to be stacked on top of containers having smaller widths.
- 17. A freight container comprising:a rigid support structure having a horizontal roof, vertical side walls, a horizontal floor, and at least one door; at least two reinforcement beams, each having a horizontal header coupled to the roof, a pair of vertical side posts coupled to the side walls, and a horizontal footer coupled to the floor, each side post having a transversely interior surface and an opposing transversely exterior surface; a stack casting disposed between each footer and each side post, the stack casting having a horizontal bottom plate, a transversely inboard stack aperture passing through the bottom plate, and a transversely outboard stack aperture passing through the bottom plate: and a lift casting disposed between each header and each pair of side posts, each lift casting comprising: a horizontal upper plate; and at least one longitudinally elongated lift aperture through the upper plate, the elongated lift aperture being located in an outboard position on the upper plate that is a transverse distance from a center of the header such that an outboard elongated side wall of the elongated lift aperture formed in the upper plate is substantially vertically aligned with the transversely interior surface of each corresponding side post.
- 18. The freight container according to claim 17, wherein the transversely outboard stack aperture is vertically aligned with the elongated lift aperture.
US Referenced Citations (12)