EP2222591B1

EP2222591B1 - Straddle carrier and method for moving freight containers across a yard

Info

Publication number: EP2222591B1
Application number: EP08859516A
Authority: EP
Inventors: Martinus Nicolaas Seine
Original assignee: Cargotec Finland Oy
Current assignee: Cargotec Finland Oy
Priority date: 2007-12-12
Filing date: 2008-12-08
Publication date: 2011-05-18
Anticipated expiration: 2028-12-08
Also published as: NL1034816C2; ATE509883T1; ES2366878T3; WO2009075569A1; EP2222591A1

Abstract

The invention relates to a straddle carrier which is provided with wheels for moving freight containers across a yard. The wheels comprise at least two steerable wheels. The straddle carrier further comprises at least one portal frame, as well as at least one frame which is movable with respect to said portal frame for picking up, lifting and/or carrying a freight container, using gripping means. The movable frame is arranged for picking up, lifting and/or carrying at least two parallel, side-by-side freight containers at a time with the longitudinal sides of the two freight containers facing each other.

Description

The invention relates to a straddle carrier provided with wheels for moving freight containers across a yard, which wheels comprise at least two steerable wheels, whilst the straddle carrier further comprises at least one portal frame as well as at least one frame which is movable with respect to said portal frame for picking up, lifting and/or carrying a freight container, using gripping means.
The invention further relates to a method for moving freight containers in a yard.
Such a straddle carrier is known from US-D-526,932S . The straddle carrier known from US-D-526,932S comprises a portal frame comprising two parallel, substantially vertically extending portal structure members, which are provided with wheels at their lower end and which are interconnected by means of at least one bridge member at their upper end. Mounted to the bridge member of the known straddle carrier is a frame that can be moved up and down for picking up, lifting and/or carrying a freight container.
The known straddle carrier has the drawback that the number of freight containers that can moved a certain distance therewith per unit time is relatively low.
The object of the present invention is to provide an improved straddle carrier by means of which a larger number of freight containers can be moved a certain distance per unit time.
This object is accomplished with the straddle carrier according to the invention in that the movable frame is arranged for picking up, lifting and/or carrying at least two parallel, side-by-side freight containers at a time with the longitudinal sides of the two freight containers facing each other.
Using such a straddle carrier, a number of parallel, side-by-side freight containers instead of a single freight container extending in the longitudinal direction can be picked up, lifted to a desired height and/or be carried to a different location in the yard and deposited at said location, for example for storage, with each moving operation. Productivity is significantly enhanced by using the straddle carrier according to the present invention.
Another advantage of the straddle carrier according to the present invention is the fact that more freight containers can be stored on the same yard area than is for example possible with the straddle carrier shown in US-D-526,932S . The fact is that space is needed between all the parallel, facing longitudinal sides of the freight containers when using the known straddle carrier, so that the wheels of the straddle carrier can move between the freight containers for picking up each freight container in the yard and moving it. With the straddle carrier according to the present invention, rows of freight containers are formed in the yard, which rows are positioned at least so far apart that the parts of the straddle carrier which are provided with wheels can move between the rows, wherein two freight containers are positioned substantially parallel beside each other in each row, such that the spacing between facing longitudinal sides of the freight containers is smaller than the aforesaid minimally required spacing between rows. By minimising said spacing between freight containers thus arranged in rows, it is possible to achieve a capacity increase of the storage yard, because more freight containers can be stored per hectare.
Furthermore, the straddle carrier according to the present invention has very advantageous dimensions. The portal frame is relatively wide, because at least two parallel, side-by-side freight containers can be picked up, lifted and/or carried by means of the movable frame between substantially vertically extending structural members of the portal frame. The straddle carrier according to the present invention thus has a width-height proportion which is relatively advantageous from the viewpoint of stability, so that the straddle carrier can travel at relatively high speeds across a storage yard, so that a larger number of freight containers can be moved a certain distance per unit time by means of the straddle carrier according to the present invention.
With the exception of the movable frame and the width dimension of the portal frame, the construction of the straddle carrier according to the present invention may be substantially the same as that of the straddle carrier that is known from US-D-526,932S .
JP-09-151076 discloses a transfer crane which comprises wheels for moving only a longitudinal direction over a yard for picking up, lifting and/or carrying freight containers by means of trolleys. These trolleys can move in a transversal direction to said longitudinal direction. A crane as a whole cannot travel at relatively high speeds across a storage yard in more than one direction.
A special preferred embodiment of the straddle carrier according to the invention is characterised in that the movable frame comprises at least two subframes, each subframe being provided with gripping means which gripping means are arranged for picking up at least one freight container.
By picking up at least one freight container with each subframe, using gripping means, at least two freight containers can be coupled to the movable frame in a relatively quick and reliable manner, which containers are jointly and simultaneously moved up or down. In this way a straddle carrier is provided by means of which a relatively high productivity level is achieved.
Another embodiment of the straddle carrier according to the invention is characterised in that the subframes are movable both with respect to each other and with respect to the portal frame.
Since the subframes can be operated independently of each other, it is for example possible to lift a first freight container by means of the first subframe while depositing a second freight container by means of a second subframe. It is also possible to position two freight containers at different heights, i.e. a first freight container on top of a vertical stack of two freight containers and a second freight container on top of a stack of three freight containers. The independently movable subframes make it possible to handle freight containers relatively quickly by means of the straddle carrier according to the present invention, thus increasing the productivity as well as the flexibility of the straddle carrier enormously.
Yet another embodiment of the straddle carrier according to the invention is characterised in that the movable frame or the subframes is/are arranged for picking up, lifting and/or carrying at least two TEU (Twenty feet Equivalent Unit) containers at a time.
TEU or teu is the standard designation for the dimension of freight containers. One (1) teu is equivalent to a container having a length of 20 ft. (6.06 m). The standard 20 ft container is 8 ft (2.44 m) wide and 8.5 ft (2.59 m) high. Two (2) teu is equivalent to two 20 ft containers or one 40 ft container.
The portal frame preferably comprises at least two parallel, substantially vertically extending portal structure members, which are interconnected by means of at least one bridge member, which bridge member is provided with a frame that can be moved up and down for picking up, lifting and/or carrying at least two freight containers between said at least two parallel, substantially vertically extending portal structure members. In the straddle carrier according to the present invention, the minimum spacing between said substantially vertically extending portal structure members is larger than 4.88 m, preferably larger than 5.5 m. As indicated above, a straddle carrier having the aforesaid dimensions has very good driving characteristics, so that it can be moved across a yard at relatively high speeds.
Another embodiment of the straddle carrier according to the invention is characterised in that the movable frame is arranged for picking up, lifting and/or carrying at least two freight containers positioned longitudinally in line with each other at a time.
In this way it is possible to move four teu freight containers simultaneously, two teu freight containers crosswise and two teu freight containers lengthwise, by means of the straddle carrier according to the present invention. Moving two containers positioned in line with each other by means of the frame leads to a further productivity increase of the straddle carrier according to the present invention. The dimension of the frame is adapted by means of telescopically extendable parts in dependence on the number of containers to be moved and/or the dimension(s) of the container(s).
Yet another embodiment of the straddle carrier according to the invention is characterised in that each subframe is arranged for picking up, lifting and/or carrying at least two freight containers positioned longitudinally in line with each other at a time.
By substituting the frame for subframes, by means of which two pairs of freight containers positioned in line with each other are movable with respect to each other, the flexibility as well as the productivity of the straddle carrier according to the invention is further increased.
The subframes are preferably provided with telescopically extendable parts for adapting the dimension of the subframes to the number of containers to be moved and/or to the dimension(s) of the container(s).
It is of course possible to use more subframes, for example four subframes, in order to increase the flexibility of the straddle carrier according to the present invention even further.
The invention will now be explained by way of an example in more detail with reference to the appended figures, in which:

Figure 1 is a front view of the straddle carrier according to the invention;
Figure 2 is a side view of the straddle carrier according to the invention;
Figures 3a, 3b are top plan views of a storage yard for freight containers.

Like parts are indicated by the same numerals in the various figures.
Figure 1 is a front view of the straddle carrier 1 according to the invention in use.
The straddle carrier 1 comprises a portal frame 3 comprising a substantially vertically extending right-hand portal structure member 5 as well as a substantially vertically extending left-hand portal structure member 7. The right-hand and the left-hand portal structure member 5, 7 are interconnected by a bridge member 9.
The straddle carrier 1 according to the present invention is suitable for moving at least one "10 ft container", "20 ft container" (teu container), "30 ft container", "40 ft container" or "45 ft container". The straddle carrier 1 according to the present invention is also suitable for moving so-called "high cube containers", which containers are higher than the standard containers, and also for moving "pallet wide containers", which containers are wider than the standard containers. For reasons of productivity, it is preferred to move more than one container 10 at a time by means of the straddle carrier 1 according to the present invention, including, for example, at least two teu containers or a combination of minimally two of the aforesaid containers, although it is possible to move only one container 10 at a time by means of the straddle carrier 1 according to the invention.
The spacing x between the right-hand and the left-hand portal structure member 5, 7 is larger than twice the width of the freight containers 10 shown in the figure. More specifically, the spacing x between the right-hand and the left-hand portal structure member 5, 7 or, in other words, the inside width of the portal frame 3, is more than 4.88 m. Preferably, however, said spacing is at least 5.5 m. A straddle carrier 1 having such dimensions can at all times be moved over two parallel, side-by-side standard containers 10 which are not spaced far apart, i.e. not more than 1 metre.
At their ends 13, 15 located near the ground surface, both the right-hand and the left-hand portal structure member 5, 7 are provided with a chassis with wheels 11, at least two of which wheels 11 are steerable, so that the straddle carrier 1 can freely move in a storage yard.
The ends 17, 19 remote from the ends 13, 15 of the right-hand and the left-hand portal structure member 5, 7 are interconnected by the bridge member 9. Two subframes 21, 23 (also called "spreaders") are mounted to the bridge member 9 of the portal frame 3. The subframes 21, 23 can be moved up and down by hoisting mechanisms 25, 27. Said subframes 21, 23 are further provided with guides 29, 31, which are movably journalled in guide rails (not shown) provided in the right-hand and the left-hand portal structure member 5, 7. Such guides 29, 31 function to ensure a stable up-and-down movement of the subframes 21, 23.
Figure 2 shows a side view of the straddle carrier according to the present invention in use.
As the figure shows, the portal structure member 5 comprises two substantially vertically extending beams 35, 37, which are interconnected at the end remote from the storage yard 43 by a substantially horizontal beam 39 of the bridge member 9. The portal structure member 7 that is not shown in figure 2 is preferably of identical design.
The end 13 of the portal structure member 5 located near the ground surface 43 comprises a chassis 45 provided with wheels 11.
The straddle carrier 1 further comprises a cabin 41, from where an operator of the straddle carrier 1 can operate the hoisting mechanisms 25, 27 and thus the subframe 21, 23 either individually or simultaneously. Furthermore, the operator can control the drive of the wheels 11 and steer the steerable wheels thereof for moving the straddle carrier 1 across a storage yard 43.
The subframes 21, 23 are attached to steel cables 49 of the hoisting mechanisms 25, 27 by means of known quick-action couplings 47, so that said subframe can be moved up and down by means of the hoisting mechanisms 25, 27.
The operation of the straddle carrier 1 according to the invention is as follows:
The straddle carrier 1 is driven to freight containers 10, 100, which have just been unloaded from a ship. Said freight containers 10, 100 must be moved to another position in the yard 43, for example for storage thereof. The freight containers 10 are "20 ft freight containers", whilst the freight containers 100 are "40 ft freight containers".
The freight containers 10, 100 are preferably positioned in rows in the storage yard (for example as shown in figure 1 and in particular in figure 3).
The containers 10, 100 can be stacked or picked up maximally 4 high by the straddle carrier 1 shown in the figures.
In figure 1, a container 10 is lifted from a stack of two containers 10 by means of the subframe 23 and the hoisting mechanism 27, whilst a container 10 is lifted from a stack of four containers 10 by means of the subframe 21 and the hoisting mechanism 25.
The containers 10 can then be moved across the yard and be positioned for storage elsewhere.
Figure 2 shows how two different sized containers 10, 100 can be moved by means of the straddle carrier 1. The figure also shows how the subframes 21, 23 can extend telescopically in horizontal direction so as to adapt themselves to the dimension of the containers 10, 100 to be moved. The subframe 21 has telescoped out for a "40 ft container" 100, whilst the subframe 23 has not telescoped out. The subframe 23 is coupled to a "40 ft container". In figure 2, the quick-action couplings 47 of the subframe 21, 23 are shown apart for the sake of clarity, whereas in actual fact they should be shown one behind another in the side view of figure 2. The containers 10, 100 are coupled to the subframe 21, 23 by means of known quick-action couplings 51, such as the so-called "twistlocks".
Using an extended subframe 21, 23, it is also possible to pick up, move and put down two "20 ft containers" 10 positioned in line with each instead of the container 100.
Figures 3a and 3b show how a storage yard for freight containers 10, 100 can be optimally utilised when using the straddle carrier 1 according to the present invention. The storage yard shown in figure 3a has a dimension l x b, for example a yard 70 m long and 43 m wide, i.e. having a surface area of 3010 m². The freight containers 10, 100 are arranged in rows 101, a row 101 being made up of at. least two parallel, side-by- side freight containers 10, 100, the longitudinal sides of which freight containers 10, 100 face each other.
In the storage yard shown in figure 3b, the freight containers are arranged in a usual manner, i.e. in rows 102 one freight container 10, 100 wide. The dimension I x b of the storage yard shown in figure 3b is slightly larger than that of the storage yard shown in figure 3a, being 72.5 x 43, i.e. having a surface area of 3117 m².
In figure 3b the containers 10, 100 have been deposited, whether or not stacked one on top of another, by means of the straddle carrier 1 known from US-D-526,932S . The spacings between the freight containers 10, 100 on the storage yard of figure 3 are substantially identical on either longitudinal side of the freight containers 10, 100, said driving spacing being sufficiently large for a straddle carrier to move therebetween.
In figure 3a the containers 10, 100 have been deposited, whether or not stacked one on top of another, by means of the straddle carrier 1 according to the present invention. The spacing 105 between the longitudinal sides of two side-by- side freight containers 10, 100 in a row 101 is smaller than the driving spacing required for the straddle carrier 1 to move therebetween. The straddle carrier 1 according to the invention can move over a row 102 shown in figure 3a for depositing and/or picking up containers 10, 100.
The storage yards shown in figure 3a and 3b are both maximally utilised, which means that the containers 10, 100 are stacked three high. The capacity of the storage yard shown in figure 3a (3010 m²), which has a smaller surface area than the storage yard shown in figure 3b (3117 m²) has increased by nearly 18 per cent by positioning the freight containers 10, 100 in rows 101. The storage yard shown in figure 3a has 420 teu stored thereon, whereas the storage yard shown in figure 3b has 357 teu stored thereon.
The spacing 105 between the containers 10, 100 in a row 101 is preferably smaller than 1 metre.
Instead of using the hoisting mechanism is 25, 27 with the steel cables 49 as shown, it would also be possible to use different mechanisms for moving the subframes up and down, for example hydraulically actuated cylinders.
In summary, the advantages of the straddle carrier 1 according to the present invention are the following: increased productivity, because more containers can be moved between various positions in a yard per unit time with the straddle carrier according to the invention, as well as increased flexibility, due to the use of the subframe, and an increased storage capacity of existing and new yards, which directly leads to a major saving in costs realised by using the straddle carrier according to the present invention. Furthermore, the straddle carrier 1 according to the present invention has an advantageous width-height ratio, so that it can be moved in a stable manner at relatively high speeds.
As a result of the increased productivity of the straddle carrier according to the present invention, fewer straddle carriers are needed for an existing storage yard, which has a positive effect as regards CO₂ emissions, maintenance costs as well as personnel costs.
In spite of the fact that the figures only shows subframes, it is also possible to provide the straddle carrier with a single movable frame, by means of which at least two parallel, side-by-side freight containers can be picked up, lifted and/or carried in one go, with the longitudinal sides of the two freight containers facing each other.
In the above detailed description, for purposes of explanation and not limitation, an example embodiment disclosing specific details is set forth in order to provide a thorough understanding of embodiments according to the present teachings. However, it will be apparent to one having ordinary skill in the according to the present teachings that depart from the specific details disclosed herein remain within the scope of the appended claims. Moreover, descriptions of well-known apparati and methods may be omitted so as to not obscure the description of the example embodiment. Such methods and apparati are clearly within the scope of the present teachings.

Claims

A straddle carrier (1) that comprises:
- a portal frame (3) comprising a substantially vertically extending right-hand portal structure member (5) and a substantially vertically extending left-hand portal structure member (7) at a distance from the right-hand portal structure member (5), said portal structure members (5, 7) being interconnected by a bridge member (9) at their upper ends (17, 19),

- a chassis (45) provided at the lower end (13, 15) of each portal structure member (5, 7), said chassis (45) comprising wheels (11), at least two of said wheels (11) being steerable so that the straddle carrier (1) can move freely in a storage yard,

- means for picking up, lifting and/or carrying at least one freight container (10, 100),

- a cabin (41) from where an operator of the straddle carrier (1) can operate the means for picking up, lifting and/or carrying the at least one freight container (10, 100), as well as the drive of the wheels (11) and steer the steerable wheels (11) thereof for moving the straddle carrier (1) across a storage yard (43),
characterised in that:

- said means for picking up, lifting and/or carrying at least one freight container (10, 100) comprises two parallel sub-frames (21, 23), which can be either individually or simultaneously operated by the operator, each sub-frame (21, 23) being movable up and down by a hoisting mechanism (25, 27) of its own, each sub-frame (21, 23) further comprising gripping means for gripping at least one freight container (10, 100), whereby at least two parallel, side-by-side freight containers (10, 100) having their longitudinal sides facing each other can be moved with the straddle carrier (1),

- each sub-frame (21, 23) comprises guides (29, 31), which are movably journalled in guide rails provided in the right-hand and the left-hand portal structure members (5, 7), said guides (29, 31) ensuring a stable up-and-down movement of the sub-frames (21, 23).
A straddle carrier according to claim 1, characterised in that the sub-frames (21, 23) are movable both with respect to each other and with respect to the portal frame (3).
A straddle carrier according to claim 1 or 2, characterised in that each sub-frame (21, 23) is arranged for picking up, lifting and/or carrying at least two TEU (Twenty feet Equivalent Unit) containers (10, 100) at a time.
A method for positioning freight containers in a yard by means of a straddle carrier (1) according to any of claims 1-3, characterised by the steps of:
- lifting at least one freight container (10, 100) with each sub-frame (21, 23),

- transporting said freight containers (10, 100) with the straddle carrier (1) to a predetermined space on the storage yard (43),

- forming rows (101) of said freight containers (10, 100) on the storage yard (43), said rows (101) being positioned at least at a driving spacing of each other such that the chassis (45) provided with wheels (11) on each side of the straddle carrier (1) can move between the rows (101), wherein at least two freight containers (10, 100) are positioned substantially parallel beside each other in each row (101), such that the spacing between two facing longitudinal sides of the freight containers (10, 100) of said row (101) is smaller than the aforesaid minimally required driving spacing between the rows (101).
A method according to claim 6, characterised in that the minimally required driving spacing between the rows (101) is about 1 metre.
A method according to claims 6 or 7, characterised in that further freight containers (10, 100) are stacked on top of the freight containers (10, 100) arranged in rows (101) by means of the straddle carrier (1).