EP2681149B1

EP2681149B1 - Method and device to stabilize an agv during transport of elevated loads

Info

Publication number: EP2681149B1
Application number: EP11707151.4A
Authority: EP
Inventors: Vincent Bourquin; Dominique DÉRIAZ; Michel Lyrstrand; Pontus Karlsson
Original assignee: TTS Port Equipment AB
Current assignee: TTS Port Equipment AB
Priority date: 2011-02-28
Filing date: 2011-02-28
Publication date: 2014-12-17
Anticipated expiration: 2031-02-28
Also published as: EP2681149A1; WO2012116729A1

Description

Technical field

The present invention relates to a method and a device to physically stabilize a load combination comprising stapled unit loads, such as at least two standard containers applied a top of each other or for instance loads loaded on pallets stacked a top of each other, and at least one Automatically or semi automatically Guided Vehicle (AGV) below said loads, together with means for fixation thereof to each other and/or to said vehicle, during transport of said loads in all directions on the aground If the load is comprised of containers they may be at least two standard containers (FEU = Forty feet Equivalent Unit = 40 container or TEU = Twenty feet Equivalent Unit = 20 container) applied a top of each other or in line, possibly both, possibly in a cassette and on top of at least one AGV. If more than one AGV is utilized, they are commonly controlled by common software. More specifically the invention deals with the issue of enhancing stability of such items (AGV+load), where the load is applied on/in and engaged to the upper side of a framework or cassette framework, the latter of which together lately has become named C-AGV being a shortform for Cassette-AGV, being in turn on its bottom side on request carried by the AGV or the AGV:s, each in turn comprising one or more bogies provided for the drivability of the whole unit. A top of each bogie the frame of the AGV is provided with means for jacking (bringing the cassette into a transport position), driving as well as means for braking The wheel-base and the traction of each bogie must at least in an initial position of introduction be held within the inner limits (as seen from above) of the transport system comprising said framework to be lifted and transported together with said loads. The transport system is mainly designed for use in harbors or the like shunting areas, but may of course be scaled up or down for other more or less similar possible uses.

Technical problem

AGV:s of the kind here meant, are normally used in areas where transport of articles, such as containers of standardized volume is frequently performed in large numbers such as in harbors. It is normally not allowed for people to stay in areas where loads of this kind is handled. Such areas are often heavy industrial applications where two or more AGV:s may be utilized in order to be able to bear more load. When loads of standardized volume are stowed in height of at least two items at a time it is required to either be mechanically fix them to each other or guide them in cell guides or the like. This creates or at least enhances a risk during transport of whole units of exposing them to unwanted momentum of inertia during actions such as start and stop of movement back and forwards, mostly, however, sideways, stop and turning during transport forward in curves, especially when exposed to heavy side winds. Since demands on transport speeds and acceleration continuously over time are increased, this is of course troublesome. Combining different effects (eg. Side winds, side acceleration, vehicle dynamics, slope), whole loads are in the risk zone of timing over. Since staff handling the standardized goods seldom are aware of the actual weight of each item (container or pallet) or for that sake its mass distribution, a unit load having a substantially higher or even unbalanced weight than another such load situated below it may be loaded a top of a much less weighing unit load. This impair dangerous risks for instability of whole units (AGV + load), since the items are meant to be transported at speeds of up to at least 6 m/s in the main transport direction and up to between 2 and 3 m/s in directions sideways. Side forces that results can be considerable, especially if maximum turning radius are utilized and heavy winds are blowing. In the future even higher transport speeds are to be expected, thus the problem as such will become larger. Sideways acceleration or retardation in sideways transport of at least 1 m/s², most likely up until 6 m/s² for emergency operation in today's ranges of transport speed are in the range of possible figures. Collapses directly or indirectly due to these reasons are simply not an issue, due to the high demands on productivity. The goods to be transported simply must reach its respective destinations as soon as possible, preferably on time, and of course without any damage whatsoever.

State of the Art

After performing a search in order to map the state of the art in the technical field, twelve references were found amongst which none were considered even slightly relevant neither to the problem solved nor to the technical solution. Simply references to stiff steerable shafts or steerable wheels, making no contribution whatsoever to the issue of stability was found. Examples can be mentioned, wherein in DE 102007050 824A1 shows a towed vehicle for carrying a predetermined load, towed behind a lorry or the like. The vehicle in question comprises wheel pairs at distinct positions of the chassis thereof, being independently controllable so as to be able to maneuver the entire combination as well as possible. Another example can be seen in WO 94/02890 where an AGV is depicted, which in order to be steerable and controllable comprise pairs of shafts at each end thereof which are individually pivotable in a horizontal plane GB2362863 also discloses a steerable crane.
It is therefore considered that Applicants own publication (TTS Review of May 2009 p14) gives a better picture of the prior art situation (See fig 9). Here is shown an Automatically Guided Vehicle for cassette handling. An AGV is introduced either sideways or longitudinally below a cassette supposed to encase at least two items, in this case containers, which may of course contain different items stapled at a stack with the same instability issues at hand. Said AGV comprise wheel-pairs turnable 360 which most certainly gives a very good manuvreability, but gives absolutely no contribution when it comes to enhancing the stability of the load unit as such with its AGV. Said publication is hereby incorporated by reference. Since none of the reference found during the novelty search are considered to deal with a problem that even seen in the widest possible field of sight comes even close to either alone or in combination solving the problem according the above, it was decided that the state of the art found during our search had nothing to contribute with.

Object of invention

A main object of the present invention is therefore considered to lie in enhancing the stability of a unit comprising a flexibly integrated arrangement of loads (such as containers or pallets) indirectly and displaceably standing on the ground and a top of each other to be randomly translated thereon. The loads can be either loaded on the AGV frame or on a cassette to constitute a unit to be transported. In the case of a load on a cassette, the vehicle can be driven in below said loads, lift it and drive away in any direction free of choice.
According to the invention the AGV to be arranged below said unit load is provided with at least one wheel-bogie, which in turn is provided with at least three wheels or pairs of wheels, said bogie being arranged controllably able to pivot in the horizontal plane in relation to a frame of said AGV while each wheel being arranged controllable able to pivot at its respective fixation point in relation to the bogie, whereby during transport in all possible directions of the load, each bogie may be translated to a position in reflation to its position of introduction that the wheels define a considerably larger traction than they do when they are maintained in their initial position before pivotation of the bogie.
This gives the bogie/-es of the AGV, with the use of thereto belonging control software, the possibility of being displaced to a position in which the traction of the bogie becomes wider than that of a drive-in width in relation to the load in its longitudinal direction, which with its containers, pallets or the like is to be lifted and transported to its future position. This enhances the stability of the whole unit both when transporting it at a given path longitudinally in curves, possibly effected by side-wind and when transporting it in a direction 90° deviant to this direction and in all directions in between.
In the embodiment shown the frame beams of the AGV are only there to hold the bogies together as a common unit. 4. Provided an appropriate coordination of two independent bogies (that could be considered as a vehicle together), the function of the frame 4 can be taken by can be taken by the cassette. The AGV has been provided with jacking means that independently act directly on said unit loads and makes the total height of the transported unit loads lower, which also contributes to the transport stability of the unit as a whole.
Also controllability is by using the invention much improved. The center of the turning radius said complete unit may by this technology be translated to any point from directly below each the pivot points of each bogie to any point in a very wide circumference to it.
According to a further developed embodiment of the invention, the bogies main dimensions differ from each other in that the dimension as seen from above is rectangular instead of being essentially square. This means that the bogies when in line with the frames thereof are longer in that direction than in a direction 90° deviant from the same.
By controlling the angular position of each bogie to be a value of between 45° and 75° where the wheels are pivotable to a larger extent than +/-45°, it will be possible to maximize the traction of the bogie even further. This will of course enhance stability of the complete unit even more than with the use of the method and device according to its initial embodiment. Finally, by an appropriate design of the wheels steering, an angular position of the bogie of 90° can be achieved, which during certain conditions allows to reach a better loading of the wheels in comparison to the 45 degrees configuration.

Description of the drawings

The invention will in the hollowing be described with reference to drawings of a preferred embodiment of the invention, in which:

Fig 1 is a perspective view shows overview picture of the whole concept together with bogies of an AGV situated below a cassette, being controllable according to the invention.
Fig 2 shows in a perspective view slightly from above a bogie of an AGV comprising two bogies having four wheels each, in a first stability enhancing position,
Fig 3 shows a bogie of an AGV corresponding to that of fig 2 as seen from above,
Fig 4 shows a bogie analogous to that of fig 3 seen in a perspective view slightly from above and In a normal transport position,
Fig 5 shows a bogie of the same type, however, now from its front,
Figs 6a to c, are schematical views of AGV:s having their bogies and wheels displaced in different patterns,
Figs 7a to 7e are schematical views of a bogie of an AGV showing yet another lot of possible petitions and patterns for said bogies and wheels,
Fig 8a to 8d each show different ways to displace the bogies and wheels when it is desired that an AGV is to "crab" in all directions between sideways and straight forward, and
Fig 9 illustrates a cassette AGV according to the technology referred to in ITS. Review of May 2009 and is here used as primary prior art.

Detailed description

According to Fig 1 there is shown a unit of what in this branch is called a Cassette Loading Unit CLU. Such a unit comprise a framework 1 made to be standing on the ground with legs 2, support pillars 3 and is preferably but not necessarily made from steel. Below this CLU is shown an Automatic Guided Vehicle AGV, comprising a framework 4 of its own being provided with bogies 5 at each end with four steerable wheels 6 each. The AGV is designed such that it may be driven in below the framework 1 either in the longitudinal direction of said framework or sideways. The framework 4 of the AGV is designed to between the bogies 5 contain an embedded driving unit (not shown), for instance a diesel engine, however, any possible unit may be used as such a driving unit (Otto with petrol, Otto with alcohol, electrical, inductive etc). The overall design of the CLU is standardized to fit certain measurements in areas such as harbors or large warehouses, where goods in large quantities are handled and stored.
According to fig 2 a more detailed view in perspective, approximately 45° obliquely both seen from above and from the side of the framework 4 of said AGV, of a bogie 5 of an AGV is shown. It comprise sturdy main beams 7, at which ends the beams 7 are fixed by commonly known Chevron elements (sturdy rubber elements - not shown) or the like to crossbeams 8. At the ends of said beams 8 the wheels 6 are fixed to joints being pivotable preferably 45° and possibly some degrees more than 45° in each direction starting from an initial position corresponding to a normal transport direction straight forward in which the wheels are in line with the framework 4 as well as with the main beams 7. Between the main beams 7 at the middle of the respectively is another crossbeam 9 pivotably journalled at 16 to the main beams 7. Below the top surface 10 thereof there is a turning unit 11 having yet another beam 12 connected thereto being fixed to the main beams 7. The turning unit 11 is able to turn the bogie preferably 90° and possibly some degrees more than 90° in each direction. Said beam 12 is in turn at its ends provided with jacking means 13 for interacting and locking to eviscerations (not shown) made on the bottom side of the framework 1 of the CLU. The jacking means may be hydraulically, pneumatically or electrically maneuvered. The same goes for the turning unit. All wheels 6 are steerably controlled under the influence of at least one tie rod 14 fixed between each wheel and its cross beam 8. These rods are like the turning unit of for that sake the jacking means driven hydraulically, pneumatically or electrically in interaction with a main control system (not shown), containing algorithms for all possible positions of all the controllable parts. The position of the AGV shown in Fig 2 is one of two possible, however, identical stabilizing wheel- and bogie positions for transporting the whole CLU sideways. This, however, means that the other bogie, situated at the other end or the frame, may be controller to the same or its inverted identical position.
From Fig 3 it is most clearly elucidated how the AGV-unit is built as it is shown from above. From the main beams 7 the cross beams 8 extend one at each end of the main beams out to its ends where the wheels 6 are arranged pivotably in a horizontal plane. The maximum pivotation of the wheels according to this embodiment is +/- 45° and is affected by the controlled tie rods 14, which act simultaneously at a common command from a control unit (not shown). It is however contemplated that the wheels, if differently fixed to the bogie, might be made able to pivot as much as +/- 180°, It should be noted that the bogie is either driven by one two or more wheels. Brakes are provided integrated in the rim area of the wheels. In the two wheel driven variant, two wheels are driven, while the other two are provided with brake units (not shown).
Fig 4 shows the device according to the invention in a perspective close to that of Fig 2, however, from another direction. In this case the bogie is in a different position corresponding to a normal driving position without the stabilization function initiated. Here also the wheel driving units together with its brakes 15 (as a unit) are shown. Inside the unit 12 there is a controllable swivel unit (not shown in detail) that enables the bogie to be pivoted in relation to its frame elements 4.
In order to show the device from all possible directions and in all possible positions Fig 5 shows the bogie's front as a plane view. From this figure it is clearly evident that the beam 12 is snugly fitted to the below side of the main beams 7 thereby being used as a counter stay. From this figure is also clearly shown the previously mentioned rubber elements 17 (Chevron elements) which are situated in V-shaped eviscerations in such a fashion that all of the load leaded on the AGV from the containers press the rubber to a very stable relation, though loose. This is a solution well known from the railway industry, but gives the bogie a possibility to even out or even eliminate problems such as holes in or bumps on the ground of up to 100mm. Below Figs 6a to 6c are described in a common context. According to fig 6a is shown one of three possible positions of the bogies 5 and wheels 8 thereof to achieve a sideways translational movement of the AGV. The bogies 5 are with regard to their centers pivoted 45°, clockwise for the in the figure left bogie, and counterclockwise for the in the figure right bogie. The second possibility in this context is to from the position shown, pivot each bogie 5, 90° counterclockwise and clockwise while simultaneously turning each of the eight wheels 6 in concert with the movement of each bogie. The third and last possibility is to make a full 90° pivotation of each of the bogies (see fig 7a), while when this position has been achieved control the wheels to a position like their starting position, in which they are pivotable each +/- 45°. To reach this third position an in between position like one of the positions shown in fig 7b to 7d will have to be used. According to figs 6b and 6c it is shown how the bogies and the wheels may be controlled to be positioned so as to move the turning center TC of the CLU Said center TC thus can be positioned anywhere on the ground, which as a bonus effect gives an extremely good maneuverability to the CLU.
Figures 7a to 7e shows examples of different positions (as previously mentioned) of the bogies and wheels in comparison to the outer limitation of the cassette. Especially fig 7e shows a bogie with its wheels in their respective initial positions, enabling a CLU having two such bogies configured in the same way to be transported straight forwardly. In order to achieve a stability enhancing position for transport straight forward one would have to employ a position like the one shown in fig 7c and thereafter turn the wheels 6' 90° clockwise. A quite considerable traction increase of twice the width of the wheels is thereby accomplished.
Figs 8a to 8d shows different bogie and wheel configurations to accomplish a "crablike" movement of the whole CLU, which may be of use in certain circumstances. Finally Fig 9 shows a a cassette AGV according to the prior art chosen as a starting point for the claimed invention. In the context it should be specifically noted that the wheel pairs of the AGV shown in this figure all are pivotable +/- 180°. They are therefore unable to deliver any contribution to enhance the stability of the AGV, or for that sake of the whole CLU with an AGV situated below it.
The invention is not to be seen to be limited by the above described embodiment, but should instead be considered so by the enclosed patent claims and the description as a whole.

Claims

Stabilisation method in order to physically stabilize a load combination comprising stapled unit loads, such as at least two standard containers applied a top of each other and at least one Automatically or semi automatically Guided driverless Vehicle (AGV) below said loads, together with means for fixation thereof to each other and/or to said vehicle, during transport of said loads in all directions on the ground, characterized in that, the AGV, arranged below said unit load, is provided with at least one wheel-bogie, which in turn is provided with at least three wheels, said bogie being arranged controllably able to pivot in the horizontal plane in relation to a frame of said AGV while each wheel being arranged controllably able to pivot at its respective fixation point, whereby during transport in all possible directions of the load, each bogie may be translated to a position in relation to its position of introduction that the wheels define a considerably larger traction than they do when they are maintained in their initial position before pivotation of the bogie.
Method according to claim 1, characterized in that, the bogie is pivotally arranged at its center as regarded perpendicularly to the horizontal, whereby the are length of its pivotation becomes equal at all the wheels, irrespective of which wheel is considered, to achieve equal distribution of load at rest.
Method according to claim 1 characterized in that the wheels of each bogie are simultaneously controlled regarding its angle of inclination so as to maintain the rolling direction of each wheel in the direction of transport, (in accordance to wheel physics, allowing for specific angle corrections at each wheel particularly in turns or when the bogie is pivoting) irrespective of which this direction is in order to as a total effect enhance the traction of the AGV,
Method according to claim 1, characterized in that the bogies by being provided with a frame that serves only to keep the AGV together and in that the AGV by being provided with jacking means that independently act directly on said unit loads, makes the total height of the transported unit loads lower and thus contributes to the transport stability of the unit as a whole.
Stabilisation device to physically control the stability of a Cassette Loading Unit (CLU), comprising stapled unit loads such as at least two standard containers applied within a loading cassette a top of each other and below which at least one Automatically Controlled Vehicle (AGV) is situated to lift and transport said CLU to an arbitrary position from any given position on the ground, characterized in that, it comprice at least one bogie fixed to a frame of an Automatically Guided Vesicle (AGV), each in turn comprising at least three wheels, also comprising means for positively controlling a pivotation of both the bogie and said wheels in the horizontal plane, to positions in which said means set the bogie/-s and the wheels in positions which simultaneously enables transport in a given direction while they maximize the stability of the CLU as a whole In the transport direction and in any cross direction.
Device according to claim 4, characterized in that the bogie comprise means to pivot the same +/- 90°, and that the wheels at their joints comprise means to pivot these +/- 45°.
Device according to claim 4, characterized in that the wheels comprise means to pivot these +/-180°.