Design of a device for interlocking a bundle of 4FOLDs-Ontwerp van een systeem voor het koppelen van een bundel 4FOLD’s

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Delft University of Technology

FACULTY OF MECHANICAL, MARITIME AND MATERIALS ENGINEERING

Department of Marine and Transport Technology Mekelweg 2 2628 CD Delft the Netherlands Phone +31 (0)15-2782889 Fax +31 (0)15-2781397 www.mtt.tudelft.nl

This report consists of 98 pages plus 19 appendices. It may only be reproduced literally and as a whole. For commercial purposes only with written authorization of Delft University of Technology. Requests for consult are only taken into consideration under the condition that the applicant denies all legal rights on liabilities concerning the contents of the advice.

Specialization: Transport Engineering and Logistics

Report number: 2013.TEL.7822

Title:

Design of a device for interlocking

a bundle of 4FOLDs

Author:

S.P. Oostlander

Title (in Dutch) Ontwerp van een systeem voor het koppelen van een bundel 4FOLD’s

Assignment: Master thesis

Confidential: yes (until February 01, 2019) Initiator (university): Prof.dr.ir. G. Lodewijks

Initiator (company): Ir. A.V.M. Meijers (Holland Container Innovations, Delft) Supervisor: Ir. W. van den Bos

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Delft University of Technology

FACULTY OF MECHANICAL, MARITIME AND MATERIALS ENGINEERING

Department of Marine and Transport Technology Mekelweg 2 2628 CD Delft the Netherlands Phone +31 (0)15-2782889 Fax +31 (0)15-2781397 www.mtt.tudelft.nl

Student: S.P. Oostlander Assignment type: Master thesis

Supervisor (TUD): Ir. W. van den Bos Creditpoints (EC): 36 Supervisor (Company) Ir. A.V.M. Meijers Specialization: TEL

Report number: 2013.TL.7822 Confidential: Yes

until February 01, 2019

Subject: Can an interlocking device for bundling folded containers be integrated into a foldable container?

Holland Container Innovations (HCI) has developed and patented seven technologies for a steel foldable maritime 40ft High Cube container designed to comply with ISO-standards and the International Convention for Safe Containers (CSC). HCI has the only CSC and ISO-certified 40ft HC foldable container in the world. HCI wants to provide its customers with a convenient and safe method of locking the bundles of folded containers. This interlocking device will be certified with the container, ensuring safe bundling and handling. This also takes away the dependency of the standard twistlocks.

Your assignment is to Research how this interlocking device can be integrated into a foldable container. The unfolded inner volume of the container must be kept as big as possible. The interlocking device is undetachable and able to withstand all loads occurring during handling and stacking.

Main research question Can an interlocking device for bundling folded containers be integrated into a foldable container?

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Preface

This report is the master thesis of Sander Oostlander. It leads to the completion of my Master of Science education in the specialisation Transport Engineering and Logistics at the department of Mechanical Engineering at the Technical University of Delft.

This report is applicable for those working and/or interested in design of transportation equipment. Especially for designers working on non-standard containers; foldable, flat rack, platform etc. This report contains the design process of a device for interlocking folded containers. The design process has been done using systems engineering.

The first chapters sketch the need for an interlocking device, resulting in the requirements and functions. The middle chapters create solutions, which combined lead to concepts. The final chapters consider these concepts resulting in a design for an interlocking device.

I would like to thank Holland Container Innovations and acknowledge all those who have contributed in my thesis. The past year has been a pleasant and significant year in my life, increasing my skills as an engineer. It results in this thesis and a tempting future as an engineer at Holland Container Innovation.

Delft, February 2014

Sander Oostlander

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Summary

All over the world containers are used for transporting cargo; in a safe and protected way from sender to receiver and vice versa. On average 20% of the containers on sea and 40% of the containers on land are transported empty (1). Holland Container Innovations (HCI) has developed a steel foldable maritime 40ft high cube container, the 4FOLD, it can save costs and space during handling and transport. The 4FOLD complies with ISO-standards and the International Convention for Safe Containers (CSC). A bundle of four folded 4FOLDs has the same external dimensions as one unfolded 4FOLD and requires no special handling or transport. Bundling four 4FOLDs requires an interlocking device. Regulations dealing with handling multiple containers at once prescribe that when the total mass of a hoisted bundle is above 20tons an interlocking device must be an integral part of the container (2). A bundle of 4FOLDs is 24tons, therefor HCI wants an interlocking device integrated and certified with the 4FOLD, to obey regulations and prevent the interlocking device from getting lost or being replaced by an uncertified and/or unsuited devices. Integrating an interlocking device is already being done in flat racks and platform containers; the industry standard is the double twistlock, attached to the container via a linkage. The double twistlock needs a ‘large box’ in the roof reducing the cargo space and when damaged or corroded it can dismantle from the container. The objective of this study is to focus on how and what kind of interlocking device can be integrated into the 4FOLD. Resulting in the following research question: Can an interlocking device for bundling folded containers be integrated into a foldable container?

In this study, systems engineering has been used to find an answer to the research question and to guide the design process of the interlocking device. The provided prerequisites from HCI and regulations of ISO, which apply for interlocking devices, are converted in multiple requirements. The main functional requirement is that the interlocking device must connect with a second 4FOLD and is secured in this connected state unless operated. To achieve interlocking, an interlocking device fulfils the following six functions:

 Connecting; with other folded containers

 Securing; so remain locked unless operated

 Loading; withstand all loads during handling and transportation

 Guiding; of the top container to the bottom container during lowering

 Operating; be accessible and for the operator

 Attaching; stay connected with the container and no loose parts

For each function possible solutions have been created. The solutions are combined into sub-concepts, based on the specific functions. The heart of the interlocking device is the connection which must be created by a coupler and connector. Seven total-concepts are created, considered and scored, chosen is the: Spreader Twist Lock (STL) because of its simple operation and robustness.

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v The designed interlocking device for the 4FOLD is based on the principle of a spreader twistlock. Spreader twistlocks penetrate corner castings in the roof and are rotated over 90 degrees, the created connection allows hoisting the container. The interlocking device is located close to the corners, where the locking within a single 4FOLD is done via hammerlocks, resulting in a favourable load path through the containers and the bundle. The location allows operation to be done via the short sides of the container, by an operator standing on the ground. The operation interface is fully separated from the fold/unfold interface, preventing confusion. The operating handle of the STL allows the ‘lock status’ to be visible via the twist lock recess. The STL is located in the roof at available volume, but still it requires a shift of some parts, resulting in a slightly reduced cargo space and visibility through the door opening. Figure A shows the functioning of the STL.

Figure A The functioning of the STL. Left: lift and rotate the STL. Middle: Guiding the top container. Right: Securing the connection by rotating the STL.

This study results in the following conclusions applicable on integrating an interlocking device into a foldable container:

 The interlocking device is the only connection between the containers within a bundle so its location should create a favourable load path through the bundle.

 Loads occurring during transporting and handling acting on the interlocking device result in reaction forces at the constraints of the interlocking device. The magnitude of the reaction forces and internal stresses in the coupler depend among other things on the spacing between the location where a load is applied and the reaction forces occur. Minimizing this spacing can reduce the magnitude of the reaction forces and internal stresses, this then reduces the dimensions needed for the interlocking device.

 An interlocking device must be operable, at individual containers and within a stacked bundle. Therefor it must be reachable from the outside and thus located near the edges of the container. The reachable part of the interlocking device must be visible from outside the container to allow a noticeable ‘lock status’.

 All containers within a bundle are produced within the tolerances of ISO 668 (3). An interlocking device must be able to work within these tolerances, so the connection of the interlocking device has a certain amount of play.

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Samenvatting

Wereldwijd worden containers gebruikt om goederen op een veilige en beschermde manier te vervoeren, van verzender tot ontvanger en visa versa. Gemiddeld worden 20% van de containers op zee en 40% van de containers over land leeg vervoerd (1). Holland Container Innovations (HCI) heeft een volledig stalen en opvouwbare 40voet High Cube container ontwikkeld; de 4FOLD. Deze container bespaart kosten tijdens overslaan en transport. De 4FOLD voldoet aan de toepasbare ISO-eisen en de International Convention for Safe Containers (CSC). Een bundel van vier gevouwen 4FOLD’s heeft dezelfde buitenafmetingen als één uitgevouwen 4FOLD en behoeft geen speciale overslag of transport. Vier gevouwen 4FOLD’s moeten echter wel gekoppeld worden om het tot één bundel te maken. Regelgeving m.b.t. het behandelen van meerdere containers tegelijkertijd schrijft echter voor dat als de totale massa van een gehesen bundel boven de 20 ton is, het koppelsysteem een integraal onderdeel van de container moet zijn (2). Een bundel 4FOLD’s is 24 ton, daarom wil HCI een vergrendel systeem geïntegreerd in en gecertificeerd met de 4FOLD. Zodat aan de regels voldaan wordt en het koppelsysteem niet kwijt kan raken of verwisseld kan worden door een ongeschikt koppelsysteem. Het integreren van vergrendelsystemen wordt al toegepast bij flatrack’s en platform containers, de standaard is het dubbel twistlock welke verbonden is via een stangenstelsel. Het dubbel twistlock bevindt zich in een ‘bakje’ in het dak, hierdoor verklein je het laadvolume. Wanneer beschadigd of gecorrodeerd kunnen dubbel twistlocks loskomen van de container. Het doel van deze studie is om te richten op hoe en wat voor koppelsysteem er geïntegreerd kan worden in de 4FOLD. Dit resulteert in de onderzoeksvraag: Kan een koppelsysteem voor het bundelen van vouwbare containers worden geïntegreerd in een vouwbare container?

Bij dit onderzoek is methodisch ontwerpen gebruikt om de onderzoeksvraag te beantwoorden en het ontwerpproces van een koppelsysteem te geleiden. De vereisten vanuit HCI en de voorschrijvingen uit ISO, welke van toepassing zijn op vergrendelen, zijn vertaald in meerdere eisen. De belangrijkste functionele eis is dat het koppelsysteem een verbinding moet maken met een tweede 4FOLD en dat deze verbinding gezekerd is. Om dit te bereiken vervult een koppelsysteem de volgende zes functies:

 Verbinden; met andere containers

 Zekeren; enkel een handeling mag ontzekeren

 Belasten; alle toepasbare belastingen tijdens overslaan en transport

 Begeleiden; van een container die vanaf boven wordt verlaagd

 Bedienen; beschikbaar zijn voor een werknemer

 Hechten; vast blijven aan de container en geen losse onderdelen

Voor elke functie zijn mogelijke oplossingen bedacht. Deze oplossingen zijn gecombineerd tot sub-concepten, gebaseerd op specifieke functies. Het hart van het koppelsysteem is de verbinding die gemaakt wordt door een koppelstuk en een connector. Zeven totaalconcepten zijn gemaakt, beschouwd en gescoord, gekozen is de: Spreader Twist Lock (STL) vanwege de eenvoudige bediening en robuustheid.

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vii Het ontworpen koppelsysteem voor de 4FOLD is gebaseerd op het principe van een spreader twistlock. Spreader twistlock’s gaan in de hoekblokken in het dak en worden 90 graden geroteerd, dit creëert een koppeling waardoor een container gehesen kan worden. Het ontworpen koppelsysteem is gepositioneerd dicht tegen de hoeken, daar waar de inwendige verbinding in een 4FOLD plaats vindt, via hammerlock’s. Dit resulteert in een gunstige krachtdoorleiding door de containers en de bundel. Deze positie staat het toe de bediening uit te voeren via de korte zijdes van de container, door een werknemer staand op de grond. De interface van het koppelsysteem is volledig gescheiden van de interface voor vouwen, om verwarring te voorkomen. De handgreep van de STL maakt het mogelijk de status van de vergrendeling zichtbaar te maken via twistlock uitsparing. De STL in gepositioneerd in beschikbare ruimte in het dak, maar vereist nog wel een verschuiving van onderdelen. Dit resulteert in een geringe verkleining van het laadvolume en geringe obstructie van de deur opening. Figuur A toont het functioneren van de STL.

Figuur A De functionering van de STL. Links: optillen en roteren. Midden: begeleiden. Rechts: roteren en zekeren Dit onderzoek resulteert in de volgende conclusies toepasbaar op integratie van en koppelsysteem in een vouwbare container:

 Het koppelsysteem is de enige verbinding tussen containers binnen een bundel, dus de positionering moet zodanig zijn dat er een gunstige krachtdoorleiding ontstaat.

 Belastingen die plaatsvinden gedurende overslaan en transport op het koppelsysteem zorgen voor reactiekrachten bij de inklemmingen van het koppelsysteem en inwendige spanningen in het koppelsysteem. De grote van de reactiekrachten en spanningen hangt o.a. af van de tussenafstand van de plaatsen waar de belasting wordt aangebracht en de reactiekracht optreed. Verkleinen van deze tussenafstand kan de reactiekrachten en spanningen verkleinen, de benodigde afmetingen van een koppelsysteem kunnen vervolgens ook verkleind worden.

 Een koppelsysteem moet bedienbaar zijn, bij zowel individuele als gestapelde containers. Daarom moet het bereikbaar zijn vanaf de buitenkant en dus gepositioneerd langs de randen van de container. Het bereikbare gedeelte van het koppelsysteem moet zichtbaar zijn vanaf de buitenzijde, zodat de status van de vergrendeling waarneembaar is.

 Alle containers binnen een bundel zijn gebouwd binnen de toleranties van ISO 688 (3). Een koppelsysteem moet instaat zijn binnen deze toleranties te werken, de gegenereerde verbinding door een koppelsysteem heeft dus een zeker mate van speling.

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List of abbreviations and denominations

The content of the report contains the following abbreviations and denominations

Abbreviations

BSR Bottom Side Rail, located in the base CC Corner Casting, located in the roof and base

CTU Cargo Transport Units

FEA Finite Element Analysis

FMEA Failure Mode and Effect Analysis

HCI Holland Container Innovations

HL Hammerlock, located in the TSRs and BSRs

ICHCA The International Cargo Handling Coordination Association, organisation dedicated to improving handling and goods movement in international supply chains

ISO The International Organization for Standardization

ISO/TR ISO Technical Report

MCA Multi Criteria Analysis

OSHA Occupational Safety & Health Administration, Federal government of the United States

STL Spreader Twist Lock, the designed interlocking device in this study SWEWL Side Wall End Wall Lock, located at both side walls

SWRL Side Wall Roof Lock, located at both side walls

TS Toggle Switch, located in the TSRs

TSR Top Side Rail, located in the roof

VTL Vertical Twin Lifting, hoisting multiple containers interlocked underneath each other

Denomination

Active When a part of the interlocking device changes in configuration or orientation during connection it’s called active

Connection When a coupler is protruded in the connector and both are orientated so that it cannot become loose, a connection is made

Connector Part of the interlocking device which is being protruded by the coupler when two containers interlock

Coupler Part of the interlocking device which protrudes the base and the roof and connectable in both

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ix Guiding The ability of the interlocking device to horizontally move a top container to

align the coupler and connector of the interlocking device

Inward position When the coupler is within the envelope set by the eight corner castings Locking Securing a state of the interlocking device

Outward position When the coupler is protruding one of the planes set by the envelope of the eight corner castings

Passive When a part of the interlocking device not changes in configuration or orientation during connecting, it’s called passive

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1. Introduction

The first paragraph introduces the 4FOLD, a foldable 40ft high cube freight container designed by Holland Container Innovations. The second paragraph describes the necessity of an interlocking device. Finally the third paragraph presents the research question for this study.

1.1 The 4FOLD

A container is a standardized transportation medium used all over the world for transporting cargo. Containers are available is many different sizes and types. Each container has eight corner castings. The dimensions between these corner casting is standardized by ISO (3) (4). Handling and transporting containers is done using these corner castings. The most commonly used container is a freight container; a fully closed metal box. The most common dimensions are a 20ft and 40ft long container. A freight container is used for various types of cargo, with various values. A close box protects the cargo and cancels the necessity of repacking between the sender and receiver. Over the world there is an imbalance in transportation, this leads to transportation of empty containers. On average 20% of the containers on sea and 40% of the containers on land are transported empty. (1) Handling and transporting an empty container costs the same as a loaded container.

Holland Container Innovations (HCI) has developed and patented seven technologies for a steel foldable maritime 40ft High Cube container; the 4FOLD. The 4FOLD complies with ISO-standards and the International Convention for Safe Containers (CSC). Since March 2013 HCI is the only company who was able to ISO certify a 40ft high cube foldable container in the world. The 4FOLD saves costs and space during transport and storage. A bundle of four folded 4FOLDs takes up the space of one regular 40ft high cube freight container. The 4FOLD can be folded and unfolded using a single crane and 3 to 5 operators. This process takes around 5 minutes per container. Figure 1 shows the 4FOLD, unfolded. Unfolded the 4FOLD is identical to a standard freight container, so it requires no special handling or transportation. Figure 2 shows a bundle of four folded 4FOLDs. The external dimensions of a bundle of four are again identical to a standard freight container, so it requires again no special handling or transportation. Figure 3 to Figure 6 shows the folding steps of the 4FOLD from unfolded to folded. For unfolding the container these steps are performed in a reverse order.

The 4FOLD comprises of six main structures. Figure 7 shows the 3D model of the 4FOLD. The base and roof are shown in respectively light and dark grey. The end and side walls are shown in beige and green. All structures are interconnected via hinges or connection rods. Figure 8 shows the location of the top side rail (TSR), bottom side rail (BSR) and the corner castings (CC). The 4FOLD has locks to secure the container in its folded or unfolded state. All locks are located on the side walls, shown in Figure 9.

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Figure 1 The 4FOLD, unfolded Figure 2 A bundle of four folded 4FOLD container, painted in the company colours of CARU.

Figure 3 The unfolded 4FOLD container Figure 4 Folding the side walls, first the right wall then the left wall over the right wall.

Figure 5 Lifting the roof and end walls, the end walls fold inwards when lowering the roof again.

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3 Figure 7 The 3D model of the 4FOLD with the base and roof in grey, the side walls in green, the end walls in beige and the

connection rods in red.

Figure 8 Detail of a corner of the folded container. Blue highlighted the: Top Side Rail (TSR), Bottom Side Rail (BSR)

and Corner Casting (CC)

Figure 9 Locks and switches for locking the folded or unfolded state

Corner Casting (CC) Located on each corner, used to hold the container handling and transporting.

Top Side Rail (TSR) Side rail located in the roof, part of the framework. Bottom Side Rail (BSR) Side rail located in the base, part of the framework. Hammer Locks (HL) Locking the roof and base to both end walls. One on each

corner of the container, in the TSR or BSR, eight in total. Side Wall End Wall locks (SWEWL) Locking the side walls to both end walls, four on each side

wall.

Side Wall Roof Locks (SWRL) Locking the side walls to the roof, nine on each side wall. Toggle Switch (TS) Sets the connection rods of the container in fold or unfold

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4 Figure 10 A folded 4FOLD on a bundle of

folded flat racks

1.2 The necessity of an integrated interlocking device

The external dimensions of a bundle of four folded 4FOLDs take up the space of one container and it requires no special handling or transportation. But having a bundle of four creates the need of an interlocking device, which interlocks the individual containers, securing the bundle for handling and transportation.

Handling two containers together, one on top of the other, connected by twistlocks is known as a vertical tandem lift (VTL). Regulations prescribe that the maximum mass of VTL is 20tons (2). A bundle of four folded containers is heavier than 20tons, as a single 4FOLD has a mass of 6tons. But the same regulations state that if the interlocking device is an integral part of the container and designed to lift other empty folded containers, VTL regulations do not apply.

HCI wants to provide its customers with a convenient and safe method of interlocking a bundle of four folded 4FOLDs. This must be done using an integrated and certified interlocking device, because the total mass of the bundle is above 20tons. Integrating an interlocking device also prevents the interlocking device from getting lost ore being replaced by an uncertified and/or unsuited interlocking device. The goal of this master thesis is to research how such an interlocking device can be integrated into the 4FOLD and design such an interlocking device.

The industry standard in interlocking is the double twistlock (described in paragraph 1.3). The drawbacks of the double twistlock for the 4FOLD appears to be the large ‘box’ needed in the roof and the possibility of dismantling due to corrosion or damage. The lock status of the double twistlock is not clearly recognizable. One must look consciously into the corner casting.

A challenge in this study is to design an interlocking device which solves the drawbacks of the double twistlock and end up with an interlocking device applicable for the 4FOLD. During this study it has always been kept in mind that the resulting interlocking device must be very durable and robust. In the transportation sector the oddest and surprising damages occur to containers due to abuse or inexplicable circumstances.

1.3 The double twistlock

The external dimensions of a single folded 4FOLD are very similar to those of a folded flat rack or platform container, shown in Figure 10. They are also handled in bundles and nearly all equipped with an integrated interlocking device; a double twistlock.

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5 The double twistlock is attached via various types of linkage systems. When not needed the double twistlock rests in a ‘box’ near the corner casting. When needed it is rotated and inserted into the corner casting. The double twistlock is than kept in place by its collar which fits into the corner casting hole. When a second container is located on top of the corner casting, the trapezoid head of the double twist lock provides guiding. When located the head of the twistlock is rotated over 90 degrees. This is done manually by protruding the holes of the corner casting.

Figure 11 to Figure 13 show a collection of photos taken from existing flat racks and platform containers at a container depot in Rotterdam in March 2013. When time passes double twistlocks can also damage or dismantle from the linkage often caused by corrosion. Perceived at a visit of a container depot, by the author. Therefor HCI wants a study which focusses on how and what kind of interlocking device can be integrated into the 4FOLD.

Figure 11 A double twistlock in a flat rack, rotated out of its box using a linkage which allows only rotation

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6 Figure 13 A double twistlock in a flat rack, rotated out of its box, placed in the corner casting and when a second

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1.4 Research question

The goal of this master thesis is to research how an interlocking device can be integrated into the 4FOLD. HCI wants a study which focusses on how and what kind of interlocking device can be integrated into the 4FOLD. Resulting in the following research question:

Can an interlocking device for bundling folded containers be integrated into a foldable container?

The most important demands from HCI for the study are: The interlocking device occupies a minimum of cargo space in the unfolded 4FOLD. The interlocking device must be able to withstand all loads occurring during handling and stacking. The interlocking device must stay connected to the container at all times (no loose parts).

Prerequisites

The following prerequisites from HCI for the 4FOLD apply for this study:

1. The interlocking device must be able to withstand occurring loads and designed using applicable ISO standards.

2. The interlocking device must interlock a bundle of four folded containers. 3. The interlocking device must be certified with the container.

4. The interlocking device must be completely attached to the container and in no circumstance be detached by the operators folding or unfolding the container.

5. The interlocking device must not penetrate the loading areas and use a minimum of inner cargo space. The cargo space must be kept water tight.

6. The interlocking device must be operated from outside the container, whether folded or unfolded.

7. From the outside it must be visible whether the interlocking system is locked or unlocked. 8. No (special) tools must be needed to operate the interlocking device.

9. A simple instruction must be enough for operators to operate the interlocking device.

10. The vertical spacing between the corner castings of a bundle of folded containers should be equal to or less than 32mm.

11. The tolerances from ISO 668, for misalignment of the interlocking device when bundling the containers must be obeyed.

12. When one or more interlocking devices are not functional it should still be possible to use four standard double twistlocks, suitable for VTL.

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2. Requirements and functions

This chapter describes requirements and functions of the interlocking device. The first paragraph describes the ISO regulations. The requirements are presented in the second paragraph. The third paragraph presents the criteria and wishes to which the interlocking device must. Finally the fourth paragraph presents the functions that the interlocking device must fulfil.

2.1 ISO regulations

There are multiple ISO requirements concerning freight containers. These deal with overall dimensions and specific dimensions of parts; like the corner castings. ISO also prescribes the minimum loads a freight container must be able to withstand to ensure safe handling and transportation. When a container is certified the applicable ISO regulations are checked.

Dimensions

All dimensions for a freight container are described in ISO 668 and ISO 1161. During transportation and handling an unfolded or folded container

no parts may protrude the outer faces of the container.

The ISO 668 dimensions allow tolerance for length and width of a container. So the four folded containers within a bundle will not necessarily have identical dimensions. A selection of ISO 668 and 1161 applicable for an interlocking device are shown in Figure 14

and Table A. Figure 14 ISO 668 Dimensions of a container

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Loads

ISO also prescribes load cases. The load cases simulate real life situations which the (interlocked bundle) container encounters during its life. The interlocking device must be able to withstand the load cases without any permanent deformation and should still be useable. All load cases based on accelerations from ISO 1496-1, 1496-5, ISO/TR 15069 and 15070 and the Code of Practice for Packing of CTU.

Accelerations of a container

A container experiences all types of accelerations during its life. These accelerations can be divided in common working conditions and maximum conditions.

Vertically; the maximum acceleration a bundle of the containers will experience in its working life is during hoisting with a gantry crane; 2.0g (5) (6) (7). During a storm at sea of; Beaufort 11 a vertical acceleration of 1.8g can occur, so near the maximum hoisting acceleration (8).

amax, vertical = 2.0g

Longitudinally; the maximum acceleration a container will experience in its working life is during railway traffic, the switching/shunting impact of two rail cars; 2.0g. During road transport the maximum longitudinal acceleration is 1.0g this value is considered a more common value (9) (10).

amax, horizontal longitudinally = 2.0g

Transverse; the maximum acceleration a container will experience in its working life is during sea transportation, the roll of the ship 0.8g. Rail and road give only 0.3g to 0.5g (9) (10).

amax, horizontal transversely = 0.8g

Safety factor

For the development of the 4FOLD HCI has used a safety factor of 1.1 on all parts, except the floor. For which a safety factor of 1.1 is used. For the design of the interlocking device the largest safety factor from HCI will be used: 1.3.

For common usage the accelerations are near half the maximum accelerations. So a safety factor of 1.3 on maximum working conditions from ISO results in a safety factor of >2 in common working condition.

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Demands for the design of the interlocking device

1. The tare mass of the 4FOLD container is T = 6 000kg 2. A bundle contains 4 folded containers

3. The container contains n interlocking devices

4. n/2 diagonal connected interlocked devices should still result in a safe connection during vertical lifting loads (not prescribed by ISO)

5. n/2 interlocking devices should still result in a safe connection during horizontal loads.

Horizontal loads may lead to a movement of the container. This can result in a situation where only the interlocking devices at one wall are loaded (9).

6. Zero friction is applied between the containers’ corner castings

Load cases applicable for designing the interlocking device

ISO 1496-5 contains two load cases which apply to a folded container: Stacking and lifting. For stacking, a vertical downward force of 942kN is applied on each corner casting. The gross mass of the container is multiplied with 1g. For lifting the tare weight of the container is multiplied by the maximum vertical acceleration during hoisting (2.0g). Lifting according to ISO is done with a connection at all four corners.

Each load case is based on a maximum acceleration or working condition. Therefor load cases are added to the prescribed load cases from ISO, resulting in the following five load cases:

Stacking A vertical load to simulate a container stack Lifting A vertical load to simulate hoisting accelerations

Shunting A horizontal load to simulate shunting of one bundle on a rail car Rolling A horizontal load to simulate rolling of a ship

Guiding A vertical load to simulate the weight of a top container during guiding

Each load case is presented below, for the situation of four interlocking devices, Figure 15 to Figure 19. Each calculated load is for a single interlocking device. Table B gives an overview of the loads in case of 2, 4, 6 or 8 interlocking devices of which 50% is locked correctly.

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Stacking

According to ISO 1496-5 a force of 942kN is applied to the top of each corner casting. The tare weight of the upper containers and an acceleration from (ISO 1496-5) of 1g results in a vertical compression force. A safety factor of 1.3 is applied on the stresses caused by stacking.

Lifting

According to ISO 1496-5 the tension force generated by the tare mass of the bottom three containers and an acceleration of 2g. A diagonal connection should be possible, so n/2 connections. This demand is not prescribed by ISO and is a safety factor by itself. A safety factor of 1.0 is applied on the lifting.

_⁄

⁄

Figure 15 Load case Stacking

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Shunting

A shunting rail car generates a deceleration of 2g. When riding single stack the upper three containers generate a horizontal longitudinal force. The shunting load is applied at two of the four interlocking devices, so n/2 connections. A safety factor of 1.3 is applied on the stresses caused by shunting.

_⁄

⁄

Rolling

A rolling ship generates a horizontal acceleration of 0,8g. This results in a horizontal transverse force. The rolling load is applied at two of the four interlocking devices, so n/2 connections. A safety factor of 1.3 is applied on the stresses caused by rolling.

_⁄

Figure 17 Load case Shunting

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13

Guiding

During lowering a container the chamfer applied to the interlocking device will correct the horizontal offset and guide the top container. But when the offset exceeds the maximum offset values the top container will remain on top of the interlocking device. When a bundle of maximum three containers is lowered on top of fourth container it is possible that all the weight is applied at a single interlocking device. A safety factor of 1.0 is applied on guiding because of the non ISO demand.

Table B shows an overview of the loads applied to the interlocking devices, based on the total number of interlocking devices.

Note 1: With just two interlocking devices it’s impossible to create a diagonal connection with 50% of the interlocking devices connected.

Note 2: Shunting and guiding are complex load cases. In Appendix B these load cases are explained.

Figure 19 Load case Guiding

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14

2.2 Requirements

The boundary conditions and the ISO regulations together lead to the following requirements for the interlocking device. They are divided in multiple categories. Killer requirements are labelled [K].

Functional requirements [K]

The interlocking device must be able to perform the following tasks:

1. Connect with a folded container, all folded containers comply with ISO 668 (Figure 20)

2. Remain (un)locked unless manually or automatically operated

3. Undetachable from the container

Performance requirements [K]

The interlocking device must comply with the following quantitative requirements:

1. Withstand all loads which are specified by ISO 1496-5

2. Withstand all horizontal loads based on maximum accelerations during transport or handling (Figure 21) 3. Guide the second container during

lowering with a horizontal miss alignment of at least 25mm transverse and 38mm longitudinal (8) (Figure 22)

Operational requirements

For operating the interlocking device, the following requirements apply:

1. No (special) tools are needed to operate the interlocking device

2. Interlocking should require as few actions as possible from a worker 3. A simple job instructions must be

enough to operate the interlocking device (Figure 23)

Figure 20 A bundle of connected 4FOLD containers, hoisted onto a trailer by a reach stacker

Figure 21 Example of acceleration values a container encounters during sea transportation. (Source: German CTU

packing guidelines www.tis-gdv.de)

Figure 22 In the black circular area's a longitudinal and transverse offset between the double twistlock and corner

casting is visible.

Figure 23 Section of the Job instruction for folding de 4FOLD, using simplified pictograms.

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15

Safety [K]

The interlocking system should be safe to use for the operator:

1. Lock (status) visible (Figure 24) 2. Accessible and usable from the outside

Constraints

The interlocking device must comply with the following requirements:

1. The dimensions of the bundle must

comply with ISO 668 dimensions and tolerances.

2. The container must remain waterproof and the interlocking device may not penetrate the loading area. A minimum of internal volume may be used by the device.

3. Certified together with the container

4. No parts may be detachable, but replaceable when damaged 5. Lifetime of 12 years, equal to the container

E.1 The interlocking device should be inside the envelope bounded by the six planes defined by the eight corner castings. During handling, transporting and stacking the interlocking device may not protrude outside this envelope.

E.2 According to ISO 1496-1 the unfolded container must be waterproof. Penetration of the cargo space leads to a reduction of the cargo volume and should be minimized. When the mechanism is visible inside the unfolded container there is a possibility that the cargo can damage the mechanism (or vice versa) or that the mechanism is used for lashing or bracing. So it should be shielded.

E.4 The interlocking device must be integrated with the container and undetachable. When the interlocking device is damaged, bend, twisted or worn it must be detachable in a workshop.

E.5 The interlocking device must be durable. It must be as durable as the other mechanisms on the foldable container. The need of maintenance must not be more than of the other mechanisms on the foldable container. Lifetime of the container is 12 years. It must withstand seawater, contamination, physical damage, scratches etc. When damaged it must be maintainable: greased, repaired or replaced. The number of load cycles the interlocking device must withstand depend on the transportation mode and number of trips. The containers will be folded/unfolded roughly 10 - 25 times a year. Only during folded transportation will the interlocking device be loaded. Resulting in 120 - 300 transportations in its service life.

Figure 24 On the left the locks on the 4FOLD in 'locked' mode, on the right in 'unlocked' mode, visible by the red

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16

2.3 Criteria and wishes

To determine which interlocking system is the best, all generated concepts are analysed using a multi criteria analysis (MCA). For this MCA the following criteria and wishes are generated. The criteria and wishes used to determine the final interlocking system are derivatives from the requirements.

Criteria

Volume The amount of volume the interlocking system needs in the cargo space of the unfolded container.

Durable How durable the interlocking system is.

Performance How well the interlocking device handles the applied loads during guiding, connecting and locking.

Operations The amount of (separate) actions needed from the operator for folding and unfolding.

Cost How much the interlocking concept costs, compared to the known cost of a common double twistlock.

Wishes

Safe operation The operation should be designed in such a way that it is safe by itself. Only correct operation should lead to a correct locking. Deviation of the operational protocol must not lead to a (partial) connection. The operator must remain on the ground during operating the interlocking device; climbing into the bundle of containers must not be necessary. The interlocking interface must be clearly separated from the folding and unfolding interface to prevent errors. Accidently using the interlocking interface when the container is unfolded must be prevented. It must be visually possible to see if the connection is made correctly.

Minimize movement When a bundle of two, three or four containers is connected the horizontal and vertical play should be minimal. Movement or play between the folded containers can lead to several positive and negative situations. Positive side effect: movement or play can reduce the forces needed to create a connection and allow a less strict alignment of components. Negative: the containers can shift making the bundle exceed the external dimensions from ISO 668. Visual alignment When a top container is positioned on top of a container a visual alignment

should support the operator in correctly positioning the top container within the limits of the miss alignment correction.

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17 The influence of each criterion in the consideration is determined using a weighing factor matrix. In this matrix all five criteria are compared with each other. When two criteria are equally important they score a factor one. When the considered criterion is more important it scores a value above one. All scorings are added and divided by the total scoring resulting in normalized weighing factors. The normalized weighing factors are the average values off multiple HCI engineers, shown in Table C. Appendix C shows the individual results of the HCI engineers.

The possible scoring factors on each criterion are in a range of 1 to 5, shown in Table D. When possible the scoring is done quantitatively otherwise it is done qualitatively.

Table C Average normalized weighing factors

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18

2.4 Functions

The requirements are converted in functions, which describe what the interlocking device will do. A function state table will show when each specific function of the interlocking device needs to be functional and available.

Functions

A. Connecting

The interlocking system must create a connection between two folded containers. A connection means restraining the bundle of folded containers in all degrees of freedom with respect to each other.

B. Securing

The interlocking device parts may in no circumstance release themselves. Vibrations, heat, dust, water, excessive forces, accelerations etc. may not lead to unlocking of the bundle. Only manual or automatic intervention by the operator may unlock the interlocking device.

C. Loading

The interlocking system must be able to withstand all expected and rational loads it encounters during its life. This means forces/accelerations during the locking process, hoisting, transporting and stacking.

D. Guiding

The folded containers must be hoisted and positioned on top of each other. The interlocking device must be able to guide a container which is being lowered. In such a way that horizontal offsets are corrected, without damaging the mechanism. The offsets which the mechanism can correct should be of the same magnitude as the offset of a (spreader) twistlock and a container.

E. Operating

The interlocking device must be accessible by an operator; its lever/handle etc. will be operated from the outside. Using the mechanism of the interlocking device must be explainable in a simple demonstration/instruction and by a graphical walkthrough manual applied on the container.

F. Attaching

The interlocking device should be attached with the container. It must stay connected to prevent parts from being lost.

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19 Five states of operations

The interlocking device has five possible states of operation. Not all functions have to be available in each state.

1. Unfolded container

When the container is unfolded the interlocking device may not penetrate the loading area and the container must be waterproof. The interlocking device must be secured in such a way that it cannot become loose without operating. The interlocking device does not have to be accessible.

2. Folded container

When the container is folded the interlocking device must be accessible. When secured the interlocking device may not become loose without operating.

3. Folded container during interlocking

The interlocking device must be accessible and useable. The interlocking device must ‘guide’ the top container onto the bottom container. The positioning skills required from the crane operator may not be greater than for interlocking with standard twistlocks or hoisting with a spreader. When the bundle of (2, 3 or 4) containers is in position the containers must be interlocked. The containers are locked together is such a way that all dimensions are within ISO 688. When secured the interlocking device may not become loose without operating. It must be visible that the interlocking device is secured correctly.

4. Folded container interlocked in a bundle of 2, 3 or 4 folded containers

The interlocking device must be secured and not become loose without operating. It must be visible that the interlocking device is secured correctly. Under all possible loads during handling and stacking the bundle must remain intact and all dimensions within ISO 688.

5. Bundle of containers being unlocked and separated into single folded containers

The interlocking device must be accessible and useable. The interlocking device must be unlocked in such a way that the bundle of folded containers can be separated by a reach stacker. When separated the interlocking device of a single folded container must be secured and may not become loose without operating.

Table E shows an overview in which state which function should be functional. Green cells indicate functional and red cells not functional.

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20 Table E Overview off all main-functions, states of operation and when a function needs to be functional and available

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21

3. Possible solutions

Each function from paragraph 2.4 can be executed in various ways. The various ways result in various solutions which satisfy a function. For nearly all functions execution can be divided in multiple solution categories, shown in Table F. Each paragraph in this chapter deals with one main function. The last paragraph gives an overview of all possible executions; a morphological table.

3.1 Connect

with

other

folded

containers

The part which protrudes is called the coupler; the part which is being protruded is called the connector. When a part changes in configuration or orientation during connecting it’s called active when it remains unchanged it’s called passive. The location of the active/passive couplers/connectors can be in the roof and/or base or vice versa.

The coupler must protrude the connector; therefor it must be positioned in such a way that it protrudes the envelope bounded by the eight corner castings. This movement is referred to as coupler protruding. The coupler has two positions the inward and outward position. The outward position of the coupler and the connection between the coupler and connector must be retained by a lock. Figure 25 shows and example of an coupler and connector.

Table F Main functions and resulting solution categories

Figure 25 Example of an passive coupler protruding from its inward to its outward positions. Example of a connector being protruded by a coupler

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22 Figure 26 A standard and commonly used Spreader

Twistlock

Active Coupler

Spreader Twistlock

The spreader twistlock is an existing coupler, used in spreaders. It moves in axial direction and rotates around the same axis. It contains one rotatable and chamfered head shown in Figure 26.

Expansion Bolt

The Expansion Bolt contains ‘flanges’ which are forced outward. When lowering the active coupler into a hole the flaps are automatically forced inwards when fully lowered the flaps will automatically unfold again. For unlocking the flaps need to be forced inward shown in Figure 27.

Hook

A hook shape is rotated or lowered and slid into a slot/hole shown in Figure 28.

Twistlock

A twistlock a used commonly on flat racks and platform containers. It contains two rotatable heads connected via a shaft which goes through a collar, shown in Figure 29.

Figure 27 Expansion Bolt principle for an active coupler

Figure 28 Hook principle for an active coupler

Figure 29 A standard and commonly used Double Twistlock

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23

Strap

Lashing the container together with a strap/cable/chain. Creating a vertical constraint only. The belt must be tensioned, this tension will generate a friction force, shown in Figure 30.

Passive Coupler

A bar

A passive bar protrudes the connector shown in Figure 31. The bar contains the ability to connect with the connector via a hole, groove, cut-out etc. A stacking cone is a standardized example of a bar, shown in Figure 32. It contains two extrusions which protrude into a hole, in this case the corner casting. The plate only creates a horizontal constraint and guides the top container vertically during locking.

Figure 31 A bar Figure 32 A stacking cone, (source: www.sec-bremen.de)

Active connectors

Sliding plates

The sliding plates are active connecters, shown in Figure 33. The active connectors contain one or two sliding plates. They have a chamfer which will transfer the vertical movement of a lowering a passive coupler into a horizontal movement which allows the sliding plates to open. A spring is tensioned during opening which will automatically close the sliding plates and locks the coupler. The coupler is now constraint by the sliding plates.

The sliding plates move in 1 direction: in a straight line or a rotation. The sliding plates are supported and guided in all other degrees of freedom. If needed parallel faces are tapered to prevent jamming.

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24 When unlocking the connector, sliding plates are forced open manually using a: linkage system and a rotatable handle, a slot and a pin, etc. The passive coupler can have various cross section shapes: square, rectangular or round. The head of the coupler

has a trapezoidal or spherical shape to automatically open the sliding plates. In the coupler a groove/cut-out is applied in which the sliding plates slide.

The pin is the active connector and a hole is part of the passive coupler. The pin slides into the hole to create a constraint connection. The pin can have different cross sections: round, ellipse, square, rectangle etc. The pin can be straight/parallel of conical in its axial direction.

The pin can be part of a hammer lock. But when the pin is equipped with a chamfer it can open and/or close automatically, shown in Figure 35 and Figure 36. The vertical movement of the lowering coupler will be transferred by the chamfer into a horizontal movement which allows the pin to slide in and open. This opens a slot in which the coupler is lowered. During sliding the pin tensions a spring which forces the pin back in its original position, but this time through the hole in the coupler.

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25 For unlocking the pin can be pulled back manually, using a linkage system, camshaft or automatically by rotating the pin 180degrees. Figure 34 shows sketches of the pin connector.

Figure 35 Hammer lock pin on the 4FOLD Figure 36 Auto pin at a flat rack, to lock the end walls in folded mode.

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26 Passive connectors

Trapezoid cut-out

A trapezoid cut-out ensures a horizontally constraint connection. Both the coupler and the connector are passive and no vertical constraint is created. The cross section of the coupler can be: square, rectangle, round etc. Figure 37 shows sketches of the trapezoid cut-out.

Hole

The simplest connector is a passive hole. The hole can have multiple shapes: round, oval, rectangle, square etc., Figure 38 A passive hole. The corner casting is a standardized example of a passive hole, Figure 39.

Figure 38 A passive hole Figure 39 Standard and commonly used corner castings Figure 37 Trapeziod cut-out

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27 Coupler protruding

In all possible solutions below the coupler is displayed as a square rod without a head, groove, spline, hole etc. The focus is on how the coupler can be moved from its inward to its outward position.

Vertical sliding

The coupler can be moved by just sliding it vertically though one of the horizontal planes. This sliding motion needs to be guided and constraint. This can be done in multiple ways. For instance: Slot trajectory and a pin, groove and a strip, side plates which form a bracket. Figure 40 shows sketches for multiple vertical sliding solutions.

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28

Rotating

Rotating the coupler can be done in multiple ways; Rotating the coupler from the horizontal plane to the vertical plane, around one axis. Rotating the coupler within the vertical plane from a horizontal orientation to a vertical orientation, again around one axis, shown in Figure 41.

Combination

The movement of the coupler can also be a combination of vertical sliding and rotating. For instance when a round coupler is guided by a bracket. When rotating the coupler around its own axis added thread can result in an axial movement, shown in Figure 42.

Figure 41 Rotating coupler

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3.2 Secure the interlocking device

The interlocking system contains two elements which need to be locked. The coupler in its inward and outward guiding position; coupler lock and the connection between the coupler and the connector; connection lock. When the coupler is in outward position and when the connection is locked the lock must be able to handle and withstand all possible loads which are applied on it. The connection may in no circumstance be unlocked without interference of the operator.

The lock can be force or shape constraint or both. A force constraint lock is kept locked by a force generated by for example; a spring, magnet or gravity. The load cases may in no circumstance generate an opposing force which unlocks the lock. A shape constraint lock is kept locked by a physical barrier: pin + hole, pin + groove, a flange, slot trajectory + handle/pin. The lock can also be combination off all these options. Figure 43 shows sketches of all possible locks.

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30 Figure 44 Cross sections of the coupler for four interlocking devices and load case 1 Stacking, at true scale

3.3 Withstand the load cases

The connection between the coupler and the connector must withstand all loads and accelerations, described in paragraph 2.1. So the coupler and connector must withstand all tension, compression and shear forces subjected to them. The minimum cross section area of the coupler depends on the load and type of steel and can have multiple shapes; round, square, etc.

Dimensions

The dimensions of the parts of the interlocking device depend on: the type of construction steel, the load and the number of parts over which the load is distributed.

Material

The material used for the interlocking device can be a general type of construction steel: S235 or

S355. When the available space is limited or the tensions are very high, higher quality alloy steel can be used. These types of steel are chosen because similar steel types are already used in the container. Non-steel material like nylon can also be used.

Production method

For producing the interlocking device a production method can be: Casting, Milling, Forging, etc. The type of method determines the final strength of the interlocking device.

Figure 44 presents the square and round cross section dimensioned for the situation of four interlocking device, load case 1 and for three material types (all at true scale). See Appendix D for more detailed dimensions and information about the materials and how the cross section areas are calculated. S235 73x73mm S355 59x59mm Cr42 43x43mm

Stacking

S235 Ø82mm S355 Ø67mm Cr42 Ø48mm

Stacking

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31

3.4 Guide the top container

An offset between the centre axis of the coupler and the centre axis of the connector in the horizontal plane of 25mm transverse and 38mm longitudinal (ISO prescribed) must still lead to a connection. When the coupler and connector touch the horizontal component of the normal reaction force generates a motion which reduces the offset to a value which leads to alignment of the centre axes. Therefor the touching parts should be a: chamfer, trapezoid, fillet, sphere etc. The angle of the touching planes determines the

magnitude of the horizontal reaction force. The touching planes should have a minimum of friction.

Coupler head and Connector edge

The coupler head can have straight planes is a Trapezoid/Pyramid shape or a curved shape Sphere. The connector edge can have straight planes a chamfer shape or a curved shape with a fillet shown in Figure 45.

3.5 Operate the interlocking device

The interlocking device must be accessible and usable by an operator. He/she must perform all actions needed to create an interlocked container pile of two, three or four folded containers. This operation is performed with an interface which contains hardware and graphics.

Operation

Manually

A manual operation can be executed by a handle/lever/pin etc. which needs to be moved/rotated/pulled out etc.

Automatically

An action; connecting, locking, unlocking etc. is done automatically during lowering or hoisting the top container without an operator driven by a force generated by gravity, a spring, a magnet etc.

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32

Combination

The operation can be a combination of manual and automatic. For example automatic locking and manual unlocking.

Interface hardware

When the interlocking device is manually operated it must have an interface. This can be a pin, handle or lever shown in Figure 46. The operation of the hardware must be a simple as possible with a minimum of degree off freedom and effort.

Interface graphics

Interface graphics should illustrate and clarify the operation and indicating if the operation is performed correct or false. Figure 47 is from the 4FOLD or made during a visit at a container depot. Figure 23 and Figure 24 are also examples of interface graphics.

Figure 47 Multiple interface graphics Figure 46 Interface hardware: a pin, handle and lever

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33 Figure 48 Possible location side rails (1)

3.6 Attach with the container

The number of interlocking devices is mainly determined by the available space and volume within the construction of the container at a specific location. The interlocking device is attached at its location with the container.

Location

Side rails (1)

The base and roof of the container contain a side rail with a C-shaped cross section in longitudinal direction. Both side rails have different dimensions. The ends of the bottom side rail contain the end wall hinge and a hammer lock. The ends of the top side rail contain a hammer lock and the toggle switch. In the side rail volume is available for an interlocking device, it may penetrate the side rails. Figure 48 the side rails are highlighted in blue.

Inner works (2)

The floor of the container contains cross members in transverse direction with a spacing of >200mm. This creates available volume for the interlocking device. In all four corners of the roof the toggle box is positioned directly under the roof and next to the top side rail. Some space exists between the toggle box and top side rail (53mm). This space could be used for an interlocking device without

interfering with the folding/unfolding of the container. Figure 49 shows the location ‘inner works’ within the blue circles, some roof and floor panels have been hidden.

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34 Figure 52 Overview off all four possible locations the interlocking

device can be positioned, in the base and roof

Corner casting (3)

Corner castings are designed to handle loads which occur during transportation and handling. Double twistlock uses the corner casting for interlocking. Making corner castings a location where the interlocking device could be located. In Figure 50 the corner castings and in-between parts are highlighted in blue.

End transverse member (4)

Both the roof and base contain a transverse member between the corner castings. The transverse member (header) in the roof is positioned just above the door opening. In Figure 51 the end transverse members are highlighted in blue.

Figure 52 shows an overview of the base and roof, both a bottom view, in which all four possible locations are indicated and numbered.

Figure 50 Possible location corner casting (3)

Figure 51 Possible location end transverse member (4)

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35 Number of interlocking devices

The number of interlocking devices depends on multiple factors. First the maximum occurring stresses and the resulting material volume need to coop with these loads. Second the available volume. Third the accessibility and number of actions needed for the operation. The minimum of interlocking devices is four, as a diagonal connection must be possible. It will always be an even number of interlocking devices, as an uneven number results in a single possible orientation of the containers within the bundle.

Attachment

The coupler of the interlocking device must be attached to the container. Multiple attachments are given below and shown in Figure 53 to Figure 58.

Chain or cable

The interlocking device can be connected by welding a chain or attaching a cable to the container and the interlocking device.

Linkage / Hinge

The linkage / hinge guide the single degree of freedom motion, making it possible to determine the movement and the position of the interlocking device.

Bracket

A bracket envelopes the interlocking device and guides its movement. The bracket can very well be part of the load bearing / support construction.

Slot + pin

A pin in a slot can create an attachment to the container and guide the motion and determine the movement and the position of the interlocking device.

Figure 53 Attachment via a chain

Figure 54 Attachment via a linkage/hinge

Figure 55 Attachment via a bracket enveloping for instance a pin

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36

Slot + strip

A slot and strip can create an attachment to the container and guide the motion in a single degree of freedom and determine the movement and the position of the interlocking device.

Ball and Socket

An attachment to the container which allows a movement in multiple degrees of freedom but with a fixed radius.

3.7 Morphological table

This paragraph presents all possible solutions, presented in a morphological table; Table G. This table is a summary of all possible solutions and the input for creating concepts. Appendix E contains an enlarged A3 print of the morphological table contains pictograms.

Figure 57 Attachment via a slot and strip

Figure 58 Attachment via a ball and socket

Design of a device for interlocking a bundle of 4FOLDs-Ontwerp van een systeem voor het koppelen van een bundel 4FOLD’s

Specialization: Transport Engineering and Logistics

Report number: 2013.TEL.7822

Title:

Design of a device for interlocking

a bundle of 4FOLDs

Author:

S.P. Oostlander

Preface

Summary

Samenvatting

List of abbreviations and denominations

Contents

1. Introduction

1.1

The 4FOLD

1.2 The necessity of an integrated interlocking device

1.3 The double twistlock

1.4 Research question

2. Requirements and functions

2.1 ISO regulations

Dimensions

Loads

⁄

⁄

⁄

⁄

⁄

2.2 Requirements

2.3 Criteria and wishes

2.4 Functions

3. Possible solutions

3.1 Connect

with

other

folded

containers

3.2 Secure the interlocking device

3.3 Withstand the load cases

Stacking

Stacking

3.4 Guide the top container

3.5 Operate the interlocking device

3.6 Attach with the container

3.7 Morphological table

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_⁄

_⁄