WO2022260193A1

WO2022260193A1 - Corner post securing device and method for tier 1 containers on the deck of containerships

Info

Publication number: WO2022260193A1
Application number: PCT/KR2021/007219
Authority: WO
Inventors: Samuel Suyoung KIM; Dong Hyun Kim
Original assignee: Komos Marine Surveyors And Engineering Consultants Co., Ltd.
Priority date: 2021-06-09
Filing date: 2021-06-09
Publication date: 2022-12-15
Also published as: KR20230151035A

Abstract

A corner post securing device for a tier 1 container on a containership deck is disclosed. The corner post securing device of the tier 1 container of the containership deck of the present invention comprises of a beam-shaped support, where one end is fixed to the corner casting of tier 1 containers and the other end is fixed to the deck of the containership; a corner post fixing means for fixing the beam-shaped support to the corner casting; a deck fixing means for fixing the beam-shaped support to the containership deck, characterized in that by clamping the corner casting located at the lower end of the corner post of the container on the deck of the containership. As a result, the corner post becomes stronger against buckling under compressive force. According to the present invention having the configuration as described above, there is an advantage that the corner post can take more bending moment when buckling, and therefore, it is possible to reduce the risk of container crushing. In addition, the invention will be applied as an additional solution to the existing cargo securing methods and practices while having a significantly low probability that the invention will interfere with the existing securing methods.

Description

CORNER POST SECURING DEVICE AND METHOD FOR TIER 1 CONTAINERS ON THE DECK OF CONTAINERSHIPS

The present invention pertains to a container cargo securing device and method on containerships. It more specifically relates to a corner post securing device for tier 1 containers on the decks of containerships that can be used as an additional cargo securing solution to the existing cargo securing method.

As containerships have become large enough to carry 20,000TEU or more, containers on board are vertically stacked as high as 9-10 containers. High container stacks have advantage in terms of efficiency in ship operations, but it results in a weak structure, which exposes cargo to a variety of ship movement caused problems such as rolling, pitching, or slamming during voyage. To carry cargo containers as safe as possible, containers on board use a number of lashing bars to tighten them onto the deck and another layer of safety solutions are also highly recommended in order to keep cargo secure.

High container stacks on board have created a new emerging risk, the crushing of tier 1 on-deck containers. This happens close to the ends of starboard and portside, where the compressive force acts as the largest of an accumulated sum of acceleration forces, weight of stacked containers, impact forces, and other external forces.

Fig. 1 is a view showing containers stacked on the deck of a containership, and Fig. 2 is a view showing the collapse of containers stacked on the container deck according to the prior art when any weakest tier 1 container collapses first.

Referring to Fig.1 and Fig.2, when any of the four corner posts in the tier 1 container 10 crushes and buckles, it causes the crash of the container and triggers the fall of the whole container stack. Because tier 1 container 10 crucially supports a whole stack, a fall of one stack will cause the neighboring container stacks in the same bay to fall like dominos.

According to the current cargo securing method, the top container in container stacks is joined with the bottom container through four corner castings by means of a twist lock method. Tier 1 on-deck containers are then joined with four sockets built on deck by means of four twist locks. Once joined, the rotating body of the twist lock is twisted to lock the joint between the top and bottom containers or the tier 1 container and socket on deck. Twist locks take tensional force and shear or compressive force, which are generated while container stacks move during a voyage or while containers are being loaded at port.

The twisting motion is smooth due to the tolerance allowed in twist locks. Zero tolerance would make container loading or unloading at ports a time-consuming task. However, the tolerance of twist locks causes the container stack to sway in a wider range during the rolling and pitching of a ship during voyage. Therefore, a lashing bar is required to tighten the container onto the ship and therefore the range of movement of the container stack can be constrained to a certain degree.

Despite using the conventional cargo securing method of using twist locks and lashing bars, it cannot mitigate the newfound risk of the crushing of the tier 1 container, which is caused by the high stack of containers on board.

Lashing bars have a drawback in mitigating the new emerging risk because they enforce additional compressive force when lashing containers onto the deck. They perform negatively to the new risk, particularly when lashing is excessively tightened.

Twist locks have a drawback within the buckling strength of the corner posts because it does not clamp the corner post to the base ground due to its tolerance. In handling the risk of container crushing, the corner post requires a stronger buckling strength in order to resist the compressive force imposed on the post. It is widely known in the world of material strength physics that the clamping joint is more resistant to buckling for a post. However, conventional twisting joints do not work as clamping joints.

Some previous solutions proposed a clamped twisting joint by embedding a screw into the body. Although the design may reduce the tolerance to zero and help in achieving a certain reduction in range of movement, the effectiveness of this solution on the new risk of container collapse is not certain.

Using a safer route for voyages may help in the mitigation of the risk, but this proposal has a limit due to the uncertain nature of rough weather.

The present invention was conceived in consideration of the problems as mentioned earlier, and its purpose is to provide a corner post securing device and a securing method for tier 1 containers on the deck of containerships. The invention recognizes that increasing the buckling strength of the tier 1 deck container's corner post is the key to mitigate the new risk of container collapse.

The corner post securing device for the tier 1 container comprises of a beam-shaped support, where one end is fixed to the corner casting of the tier 1 container and the other end is fixed to the deck of the containership; a corner post fixing means for fixing the beam-shaped support to the corner casting; and a deck fixing means for fixing the beam-shaped support to the containership deck. The reason behind this is that by clamping the corner casting located at the lower end of the corner post of the container to the deck of the containership, the corner post becomes stronger against buckling under compressive force.

Preferably, the corner post fixing means includes: a corner post coupling plate bent from one end of the beam-shaped support to the lower end and having a side coupling hole formed in the center thereof; a corner post fixture which is composed of an end plate inserted into the long hole of the corner casting and fixed by twisting; a protruding bolt that is inserted into the side coupling hole of the corner post coupling plate while extending from the central portion of the end plate and fixed with a nut.

Preferably, the deck fixing means includes: a deck socket installed on the deck of the containership and having a housing with a cavity therein and a socket hole in the shape of a long hole connected to the cavity as an upper portion; a socket coupling plate having a upper-lower coupling hole formed at the other end of the beam-shaped support; a socket fixture which is composed of an end plate that is inserted into the socket hole of the deck socket and fixed by twisting; a protruding bolt that is inserted into the upper-lower coupling holes of the socket coupling plate while extending from the center of the end plate and fixed with a nut.

Preferably, the deck fixing means includes: a pad eye installed on the deck of the containership, having a protruding plate extending from the deck, and a through hole penetrating the extended protruding plate; a pad eye coupling plate having front-rear coupling holes formed at the other end of the beam shaped support; a bolt and a nut fastened through the through hole of the pad eye and the front-rear coupling holes of the pad eye coupling plate.

Preferably, the cross section of the beam-shaped support is I-shaped, T-shaped, or rectangular shape.

The invention proposes how to achieve a clamping joint that connects the corner post with the socket built on deck for tier 1 on-deck containers.

To begin with, in the example of a streetlight, the post is planted deep into the ground like a pile, or it utilizes a bracket-shaped stand at the bottom of the post. Due to this, the post can stand still even under external forces that could make it fall or bend. Similarly, the clamping joint can also bear a bending moment generated from a situation when the post is bent or buckled by any external force.

The invention cannot take an option like piling because the ship structure does not allow it, but the other option of using a stand as stated in the previous paragraph can be feasible. The method incorporates the mounting of a beam-shaped support on the corner casting using a bolt & nut, which is then attached to the bottom end of a corner post. The other end of the beam-shaped support is fixed on the socket using a bolt & nut, which is then built on deck in order to support 20' containers. Like the example of a stand in the streetlight, the beam-shaped support will help the corner post resist external forces such as bending, where the lengthened support will enable it to resist a larger bending moment.

The invention mainly targets 40' containers, the most used container size, however the method can be applied to other sizes. In the example of a 40' container, there are extra sockets available to mount tier 1 on-deck 20' containers.

It was explained previously that conventional lashing bars do not help with dealing with compressive forces imposed on the corner post. And for a conventional twist lock, it is designed to mainly bear tensional and shear force under rolling or pitching of the ship, but it has a limit in taking sufficient bending moment generated from corner posts being buckled due to its geometry and tolerance.

Therefore, the invention has its merit in that it can take a larger amount of bending moment when the post is buckled and consequently, it can help mitigate the risk of container crushing.

The invention will be applied as an additional solution to the existing cargo securing methods and practices. Also, there is a significantly low probability that the invention will interfere with the existing securing methods.

The invention will allow the existing twist lock to bear the majority of the tensional force generated on the joint when the container stack sways under a ship's rolling and pitching.

The invention can be selectively applied to the weakest tier 1 on-deck container in a containership or on the weakest corner post of a container.

The invention is applied mainly to 40' containers.

According to the present invention having the configuration as described above, there is an advantage that the corner post can take more bending moment when buckling, and as a result, it is viable in reducing the risk of container crushing.

The invention will also be applied as an additional solution to the existing cargo securing methods and practices while posing a significantly low probability of interference with the existing securing methods.

The above object and advantages of the present invention will become more apparent by describing in details exemplary embodiments thereof with reference to the attached drawings in which:

Fig. 1 is a view showing containers stacked on a containership deck.

Fig. 2 is a view showing the collapse of containers stacked on the container deck according to the prior art.

Fig. 3 is an exploded perspective showing a corner post securing device using a beam-shaped support that receives a bending moment generated by the buckling of a tier 1 container corner post according to a first embodiment of the present invention.

Fig. 4 is a view showing a corner post fixture fixed to a corner casting of a container according to a first embodiment of the present invention.

Fig. 5 is a view showing a socket fixture fixed to an extra socket built on the containership deck according to a first embodiment of the present invention.

Fig. 6 is a view showing an assembly state of a corner post and an extra socket of a container using the corner post fixing device of the container according to a first embodiment of the present invention.

Fig. 7 is an exploded perspective view showing a corner post securing device of a container using a beam-shaped support that receives a bending moment generated by buckling of a tier 1 container corner post according to a second embodiment of the present invention.

Fig. 8 is a view showing an assembly state of a corner post and a pad eye of a container using a corner post securing device of a container according to a second embodiment of the present invention.

Hereinafter, a corner post securing device for a container according to a preferred embodiment of the present invention will be described in details with reference to the accompanying drawings.

The present invention can be used without interference in a state in which cargo is secured using a conventional twist lock and lashing bar system.

First, the present invention will be applied to all weak tier 1 containers on deck and corner posts selected.

In general, they are used on tier 1 on-deck containers located close to the ends of starboard and portside in the ship because the acceleration force in those locations is larger. However, containers in other locations may be first applied due to inherent damage of the container, an incorrectly shipped weight, and so on.

Fig. 3 is an exploded perspective view showing a corner post fixing device using a beam-shaped support for receiving a bending moment generated by the buckling of a tier 1 container corner post according to the first embodiment of the present invention.

Referring to Fig. 3, the corner post securing device 100 includes a beam-shaped support 110, a corner post fixture 120 coupled to one end of the beam-shaped support 110, a socket fixture 130 coupled to the other end of the beam-shaped support 110, and a deck socket 140 coupled to the socket fixture 130.

The beam-shaped support 110 includes a body 111 extending in the longitudinal direction, a corner post coupling plate 113 bent from one end of the body 111 to the bottom, and a socket coupling plate 115 formed at the other end of the body 111. The corner post coupling plate 113 has a side coupling hole 117 formed in the center portion. The socket coupling plate 115 has an upper-lower coupling hole 119. The cross-section of the beam-shaped support 110 may be any one of an I-shape, a T-shape, or a rectangular shape. In addition, the beam-shaped support 110 may be formed to be inclined downward from the upper portion of the corner post coupling plate 113 in the direction of the socket coupling plate 115.

The corner post fixture 120 and the socket fixture 130 are respectively composed of

end plate

121 and 131 and projecting

bolt

123 and 133 extending from the center of the

end plate

121 and 131.

The deck socket 140 is installed on the deck of the containership and has a housing 141 having a cavity therein and a socket hole 143 in the shape of a long hole connected to the cavity in the upper portion.

Fig. 4 is a view showing a corner post fixture fixed to the corner casting of the container according to the first embodiment of the present invention.

Referring to Fig. 4, the end plate 121 is inserted into the long hole 311 of the corner casting 310 at the bottom of the corner post 20 of the container and the end plate 121 is twisted to be fixed to the long hole 311.

The lower portion of the corner casting 310 of the container is locked up and down with a socket 313 on the deck of the containership using a twist lock 400. The corner post securing device 100 of the present invention can be used without interfering with the function of the conventional twist lock 400.

Fig. 5 is a view showing a socket fixture fixed to an extra socket of the containership deck according to the first embodiment of the present invention.

Referring to Fig. 5, the end plate 131 in the socket direction is inserted into the deck hole 143 of the deck socket 140 formed on the deck of the container and twisted to be fixed to the deck socket 140. The general-purpose 20' deck socket 140 already built on the deck may be used or the deck socket 140 can be added for the purpose.

Fig. 6 is a view showing an assembly state of a corner post and a deck socket of a container using the corner post securing device of the container according to the first embodiment of the present invention.

Referring to Fig. 6, the post fixture 120 coupled to one end of the beam-shaped support 110 is fixed to the corner casting 310 located under the corner post 20 of the tier 1 container 10. The deck fixture 130 coupled to the other end of the beam-shaped support 110 is fixed to the deck socket 140 formed on the deck of the container.

One end of the beam-shaped support 110 of the present invention is mounted on the corner casting 310, and the other end of the beam-shaped support 110 is mounted on the deck socket 140 installed on the deck. The beam-shaped support 110 is characterized in that it has a structure capable of resisting the bending moment generated when the corner post 20 is buckled by the accumulated compressive force.

The corner post securing device 100 of the present invention will allow the existing twist lock 400 to bear the majority of tensional force generated on the joint when the container stack sways under a ship's rolling and pitching.

The number of bolt and nut sets used in the post fixture 120 and socket fixture 130 of the present invention is shown as only one, but this may be increased as required.

Installation and dismounting of the corner post securing device 100 to the corner post 20 according to the first embodiment are as follows.

Referring to Fig. 3 to 6, the end plate 121 of the post fixture 120 is connected to the corner casting 210 at the lower end of the corner post 20. The protruding bolt 123 is fixed with the corner post coupling plate 113 at one end of the beam-shaped support 100 with a nut 125, but is not tightened yet.

The end plate 131 of the socket fixture 130 is connected to the deck socket 140 for the 20' container. The protruding bolt 133 is fixed to the socket coupling plate 115 at the other end of the beam-shaped support 100 with a nut 135, but is not tightened yet.

First, the end plate 121 and the corner post coupling plate 213 are tightened with the protruding bolt 123 and the nut 125 at one end of the beam-shaped support 110. Here, it is checked whether the end plate 121 of the corner post fixture 100 is completely fixed to the inside of the long hole 311 of the corner casting 310.

Next, the end plate 131 and the socket coupling plate 115 are tightened to the deck socket 140 with the protruding bolt 133 and the nut 135 at the other end of the beam-shaped support 110.

After the securing of one corner post 20 is completed, it moves to the next corner post 20 and repeats installation of the post securing device 100 as described above.

The corner post 20 in the tier 1 deck container 10 can be secured to the deck using four corner post securing devices 100.

Alternatively, the corner posts 20 may be selectively secured. For example, only two corner posts 20 at the front end or the rear end of the container may be secured using the two corner post securing devices 100.

Dismounting of the corner post securing device 100 to the corner post 20 proceeds in the reverse order.

First, the socket coupling plate 115 and the end plate 113 are separated from the deck socket 140, and then the corner post coupling plate 113 and the end plate 121 are separated from the corner casting 310.

Be sure to collect the corner post fixtures 120 and the deck fixtures 130 for storage and assemble them back to the beam-shaped support 110 so no parts will be lost and none of the fixture parts will drop when the container is lifted for discharge.

When dismounting is all completed, the routine unlocking process of conventional cargo securing tools, twisting locks 400, and lashing bars can begin.

The invention can be selectively applied to any weakest container in the containership, any weakest corner post 20 in the container according to calculations, applied only under challenging voyage routes with rough weather, or in sail with an extremely high stack containing a significant amount of weight.

Referring to Fig. 7, the corner post securing device 200 includes a beam-shaped support 210, a corner post fixture 220, and a pad eye 230.

The beam-shaped support 210 includes a body 211 extending in the longitudinal direction, a corner post coupling plate 213 bent from one end of the body 211 to the bottom, and a pad eye coupling plate 215 formed at the other end of the body 211. A side coupling hole 217 is formed in the center of the corner post coupling plate 213. The front-rear coupling holes 219 are formed in the pad eye coupling plate 215.

The corner post fixture 220 is composed of an end plate 221 and a protruding bolt 223 extending from the central portion of the end plate 121, as in the first embodiment. The protruding bolt 223 is screwed with the nut 225.

The pad eye 230 is fixed on the deck of the containership, having a protruding plate 231 extending from the deck, and includes a through hole 233 penetrating the extended protruding plate 231.

Fig. 8 is a view showing an assembly state of a corner post of a container and a pad eye using the corner post securing device of the container according to the second embodiment of the present invention.

The corner post fixture 220 coupled to the corner post coupling plate 213 of one end of the beam-shaped support 210 is fixed with a corner casting 310 located under the corner post 20 of the tier 1 container 10. This is the same as the first embodiment.

Meanwhile, the pad-eye coupling plate 215 at the other end of the beam-shaped support 210 is in contact with the pad-eye 230. The through hole 233 of the pad eye 230 and the front-rear coupling holes 217 of the pad eye coupling plate 215 are fastened with the bolt 240 and the nut 241.

The pad eye 230 of the Fig. 7 and 8 is formed in a direction parallel to the beam-shaped support 210. Alternatively, it may have a direction perpendicular to the beam-shaped support 210 and, in this case, the pad-eye coupling plate of the beam-shaped support will have a shape bent downward similarly to the corner post coupling plate, unlike the Fig. 7 and 8.

While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

The invention will be applied as an additional solution to the existing cargo securing methods and practices while having a significantly low probability that the invention will interfere with the existing securing methods.

Claims

Corner post securing device of tier 1 containers on the deck of a containership, comprising of:

a beam-shaped support, where one end is fixed to the corner casting of tier 1 containers and the other end is fixed to the deck of the containership;

a corner post fixing means for fixing the beam-shaped support to the corner casting;

a deck fixing means for fixing the beam-shaped support to the containership deck,

characterized in that by clamping the corner casting located at the lower end of the corner post of the container on the deck of the containership. As a result, the corner post becomes stronger against buckling under compressive force.
Corner post securing device of claim 1, characterized in that

the corner post fixing means, comprising of:

a corner post coupling plate bent from one end of the beam-shaped support to the lower end and having a side coupling hole formed in the center thereof;

a corner post fixture which is composed of

- an end plate inserted into the long hole of the corner casting and fixed by twisting.

- a protruding bolt that is inserted into the side coupling hole of the corner post coupling plate while extending from the central portion of the end plate and fixed with a nut.
Corner post securing device of claim 1, characterized in that

the deck fixing means, comprising of:

a deck socket installed on the deck of the containership and having a housing with a cavity therein and a socket hole in the shape of a long hole connected to the cavity as an upper portion;

a socket coupling plate having an upper-lower coupling hole formed at the other end of the beam-shaped support;

a socket fixture which is composed of

- an end plate that is inserted into the socket hole of the deck socket and fixed by twisting.

- a protruding bolt that is inserted into the upper-lower coupling holes of the socket coupling plate while extending from the center of the end plate and fixed with a nut.
Corner post securing device of claim 1, characterized in that

the deck fixing means, comprising of:

a pad eye installed on the deck of the containership, having a protruding plate extending from the deck, and a through hole penetrating the extended protruding plate;

a pad eye coupling plate having front-rear coupling holes formed at the other end of the beam shaped support;

a bolt and a nut fastened through the through hole of the pad eye and the front-rear coupling holes of the pad eye coupling plate.
Corner post securing device of claim 1, characterized in that

the cross section of the beam-shaped support is any I-shape, T-shape, or rectangular shape.