Method and unit for conveying load carriers

In a method for conveying laden or unladen load carriers, the load carriers are conveyed by a first conveying system and a second conveying system which differ from one another in conveying terms. At least one load carrier is picked up and conveyed, at least temporarily, by in each case one conveying device of the first conveying system independently of the second conveying system. The second conveying system at least temporarily conveys a conveying device or an assembly which is formed by a conveying device and at least one load carrier brought together with the latter. A unit for this purpose is also specified.

RELATED APPLICATIONS

This application is a national phase of International Patent Application No. PCT/EP2014/002087, filed Jul. 30, 2014, which claims the filing benefit of German Patent Application No. 10 2013 014 102.8, filed Aug. 23, 2013, the contents of both of which are incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a method for conveying laden or unladen load carriers, in which the load carriers are conveyed by a first conveyor system and a second conveyor system which differ from one another in conveying terms.

The invention moreover relates to an installation for conveying laden or unladen load carriers, having a first conveyor system and a second conveyor system which differ from one another in conveying terms.

BACKGROUND OF THE INVENTION

The term load carriers below can refer to both laden load carriers and empty load carriers.

Conveyor installations frequently have a plurality of operating zones which are linked to one another in conveying terms and in which material to be conveyed and the conveying paths thereof are managed with different objectives.

The operating zones can be work stations in which the material to be conveyed is treated or processed. In particular, however, operating zones can be different logistics zones of a logistics system in which material to be conveyed is picked.

A first logistics zone is then, for example, an inbound delivery zone in which material to be conveyed is delivered. The material to be conveyed is located here on load carriers, such as are known for example in the form of pallets. Euro pallets have become particularly well-established as load carriers.

The material to be conveyed is then conveyed on the load carrier to further logistics zones, such as a storage zone or an order picking zone or the like, and from there to an outbound delivery zone. Between inbound delivery zone and outbound delivery zone, the material to be conveyed can cross only a single logistics zone of this type, although it can also pass through a plurality of different logistics zones. For example, material to be conveyed can be moved directly from the inbound delivery zone to an order picking zone and from there to an outbound delivery zone. However, the material to be conveyed can also firstly be conveyed to a storage zone, be stored temporarily there and then arrive at the outbound delivery zone via the order picking zone at a later time.

Conveyor systems, which differ in conveying terms and which operate in some cases manually and in some cases automatically, can be established in all logistics zones present depending on the operating concept of the particular zone. The term manual conveyor system is used here to refer to all conveyor systems in which an operator carries out the essential conveying steps. For example, a motor-driven but human-controlled forklift therefore also counts as a manual conveyor system.

In the inbound delivery zone mentioned, the forklift system is for example a first conveyor system. Overhead track systems can be effective, for example, as a second conveyor system in a storage zone, whilst a floor-guided conveyor system is preferably used as a further conveyor system in an order picking zone in which order pickers have to access conveyed objects. It is also possible for different conveyor systems to be present within individual logistics zones.

Between two conveyor systems which differ in conveying terms, there is always a handover station in which the load carriers are then transferred with the material to be conveyed from one conveyor system to another conveyor system. To this end, either stationary automatic transfer systems are present in a handover station of this type, or the material to be conveyed is transferred manually by personnel on site, for which the corresponding equipment and personnel have to be available in the handover station. Even the case where only one logistics zone, for example an order picking zone, is passed through between the inbound delivery zone and the outbound delivery zone, two handover stations are required. All in all, this results in a relatively high expenditure on materials and possibly personnel.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a method and an installation of the type mentioned at the outset which take these considerations into account.

This object may be achieved in a method of the type mentioned at the outset in thata) at least one load carrier is received and conveyed at least temporarily by in each case one conveyor device of the first conveyor system, independently of the second conveyor system;

andb) a conveyor device or an assembly, which is formed by a conveyor device and at least one load carrier which is brought together with this conveyor device, is conveyed at least temporarily by the second conveyor system.

According to the invention, one conveyor system is therefore used on the one hand as an independent conveyor system with which the laden or unladen load carriers can be conveyed; to this end, this conveyor system comprises corresponding conveyor devices. On the other hand, a conveyor device of this type, together with a received load carrier, can be conveyed along, virtually “piggyback”, by the second conveyor system. The first conveyor system with the conveyor devices therefore operates across conveyor systems. In this case, a conveyor device which is already located on the second conveyor system can part with the load carrier there and be conveyed separately or move independently. As mentioned, the load carriers can be laden or unladen, that is to say an empty load carrier on a conveyor device is also regarded as an assembly.

The conveyor devices of the first conveyor system can also take over the handover to the second conveyor system in this way. If there are a plurality of handover regions between two conveyor systems, all system handovers can take place by means of the first conveyor system. However, it goes without saying that it is also possible to use known handover methods, which are then supplemented by the method described here.

It is particularly favourable if at least one assembly is conveyed at least temporarily by a further conveyor system, which differs from the second conveyor system in conveying terms. Therefore, if a plurality of different conveyor systems are present as described above, an assembly which is formed by a conveyor device and at least one load carrier can therefore be conveyed from both logistics zones. The handover of the load carrier from one conveyor system to the other conveyor system can then take place again by means of by the conveyor device, i.e. the assembly moves as a whole from the one conveyor system to the other conveyor system.

This is particularly favourable if the second conveyor system is operated in one or more operating zones and the third conveyor system is operated in another operating zone. In this case, the first conveyor system with the conveyor devices is therefore operated across zones and can replace all normally required handover stations.

According to the invention, at least two cooperating conveyor units are preferably used as the conveyor device of the first conveyor system, each of which conveyor unitsa) comprises a chassis which can be moved on floor rollers;b) comprises a supporting element which is carried along by the chassis and can be lifted or lowered in relation to the chassis in such a way that, in an empty configuration, the conveyor unit can move under a load carrier and, in a conveying configuration, can receive and convey a load carrier by means of the supporting element;c) comprises a drive system by means of which at least one of the floor rollers can be driven.

Conveyor skids are particularly used as conveyor units.

With reference to the installation of the type mentioned at the outset, the object described above may be achieved in thata) the first conveyor system comprises a plurality of conveyor devices;b) at least one load carrier in each case can be received and conveyed independently of the second conveyor system by the conveyor devices;c) an assembly, which can be conveyed by the second conveyor system, is formed by in each case one conveyor device and at least one load carrier which is received by this conveyor device.

The advantages of this and of the features below correspond essentially to the advantages explained above in relation to the method.

It is therefore favourable if at least one further conveyor system is present, which differs from the second conveyor system in conveying terms and by means of which at least one assembly can likewise be conveyed.

The second conveyor system is preferably arranged in one of a plurality of operating zones and the third conveyor system is preferably arranged in a second operating zone.

According to the invention, a conveyor device of the first conveyor system comprises at least two cooperating conveyor units, each of whicha) comprises a chassis which can be moved on floor rollers;b) comprises a supporting element which is carried along by the chassis and can be lifted or lowered in relation to the chassis in such a way that, in an empty configuration, the conveyor unit can move under a load carrier and, in a conveying configuration, can receive and convey a load carrier by means of the supporting element;c) comprises a drive system by means of which at least one of the floor rollers can be driven.

In this arrangement, the conveyor units are preferably constructed as conveyor skids.

The conveyor systems can cooperate particularly effectively if the second and/or the third conveyor system is an overhead track system or a lift system. However, it is also possible to use ropebelt, belt or chain conveyors for the second and/or third conveyor system.

It is to be understood that the aspects and objects of the present invention described above may be combinable and that other advantages and aspects of the present invention will become apparent upon reading the following description of the drawings and detailed description of the invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail one or more embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated.

InFIGS. 1 to 4, 10denotes a first conveyor system as a whole, by means of which laden or unladen load carriers12can be conveyed. Pallets, such as are known per se, are shown as an example of load carriers12inFIG. 2and also inFIGS. 6 to 11.

A load carrier12has a supporting surface12aon which material to be conveyed14is deposited and fastened, as shown inFIGS. 6 to 11. The supporting surface12arests on a floor16by way of bearing elements12b. A respective opening12cremains between two adjacent bearing elements12band is open downwards towards the floor16and at both end faces. In particular, a load carrier12of this type can be constructed as a so-called Euro pallet.

The conveyor system10comprises a plurality of conveyor devices18which can be moved on the floor16and of which one is shown in each case inFIGS. 1 and 2. A conveyor device18is in turn formed by two conveyor units20. In the present exemplary embodiment, the conveyor units20are constructed as conveyor skids22. These can have an outer contour, for example, which corresponds approximately to that of a fork of a forklift.

These conveyor units20communicate in a manner known per se with a central control (not shown specifically) which coordinates the conveying process.

InFIGS. 3 to 5, one of the conveyor units20of the conveyor device18is now shown separately. The conveyor unit20comprises a chassis24which can be moved on floor rollers26and defines two end regions24a,24b.

The chassis24moreover carries along a supporting element28, which can be lifted or lowered in relation to the chassis24; this is merely represented inFIG. 1by double-headed arrows. If the supporting element28assumes a lowered position, the conveyor unit20is in an empty configuration in which it can move under the load carrier12. To this end, the conveyor unit20is matched to load carriers12to be conveyed in terms of its outer contour. In the case of a pallet, this means that, in its empty configuration, the dimensions of the conveyor unit20are such that it can move into one of the openings12cof the pallet so that the conveyor unit20is located in this opening12cunder the supporting surface12aof the pallet.

Conversely, the load carrier12also has to be adapted to the conveyor units20and provide at least two such openings12c.

The supporting element28of a conveyor unit20is then lifted in relation to the chassis24. If the supporting element28assumes a lifted position, the conveyor unit20is in a conveying configuration in which it can receive and convey a load carrier12by means of its supporting element28.

In a conveyor device18comprising two conveyor units20, the two conveyor units20move next to one another in coordinated manner into the adjacent openings12cin the load carrier12, as shown inFIG. 2. The supporting elements28of the two conveyor units20are then lifted in synchronised manner so that the load carrier12is lifted as a whole, and optionally with the material to be conveyed14placed on it. The load carrier12can then be conveyed to another location with the aid of the conveyor device18.

The matching and possible synchronisation of the control procedures for the conveyor units20and their movements can be coordinated by way of the central control mentioned and, alternatively or additionally, with the aid of on-board controls (not shown specifically) of the conveyor units20.

Each conveyor unit20comprises a drive system30by means of which the floor rollers26and the supporting element28can be driven.

To this end, the chassis24supports a respective drive assembly32at its two end regions24a,24b, which is mounted such that it is rotatable about an axis of rotation34. The axes of rotation34are only shown inFIG. 3and extend vertically when the conveyor unit20rests on the floor16with the floor rollers26.

The drive assemblies32each carry a respective electric motor36for each floor roller26, each of which is in geared connection with the associated drivable floor roller26, or the bearing axis thereof, by way of gear means38. In a modification which is not shown specifically, the floor rollers26can also be driven without interconnected gear means38.

The conveyor units20are now moved in that the electric motors36are supplied with current in mutually co-ordinated manner, as a result of which each floor roller26can be driven specifically and individually in a particular direction of rotation and at a particular speed.

If all four floor rollers26of a conveyor unit20are aligned transversely to the longitudinal direction of the conveyor unit20and all four electric motors36are controlled identically, the conveyor unit20assumes a linear travel configuration and drives straight ahead; this is shown by way of example inFIG. 4.

For curved travel, the alignment of the axes of the floor rollers26has to be altered in relation to the longitudinal direction of the conveyor units20. To this end, the two floor rollers26of a drive assembly32can be driven in opposite directions or at a different speed, as a result of which the drive assembly32with the floor rollers26rotates about the axis of rotation34. The conveyor unit can therefore assume the curved travel configuration shown inFIG. 5, for example, and drive through a circular curve40indicated therein if the drive assemblies32are aligned so that the axes of the floor rollers26are perpendicular to the circular curve40to be followed. In the case of a conveyor device18with two conveyor units20, a pallet14can then be rotated on the spot, for example, if all drive assemblies32are aligned on one and the same circle in this way.

For curved travel, the control takes into account the different paths of the radially outer floor rollers26(relative to the curve) with respect to the radially inner floor rollers26. By altering the speeds of the different floor rollers26, it is also possible to adapt the direction and the radius of the curves whilst travelling, so that it is possible to specify different travel paths.

A type of parallel displacement of a load carrier12can take place for example if the drive assemblies32of both conveyor units20of a conveyor device18are initially rotated in the same direction of rotation and through the same rotational angle about the axis of rotation34and the floor rollers26are then all driven synchronously and identically.

The lifting and lowering of the supporting element28can be enabled for example in that the supporting element28is coupled to the drive assemblies32by way of a respective screw drive. The drive assemblies32can be rotated on the spot about the axis for rotation34, which then effects a lifting or lowering of the supporting element28depending on the direction of rotation.

FIG. 6shows an inbound delivery zone46as an example of a first operating zone42of a logistics system which is denoted as a whole by44.

In this, material to be conveyed14is delivered on load carriers12in the form of so-called Euro pallets50by lorries48, with lorries48merely being used as an example to represent any means of transportation. The conveyor skids22of the conveyor devices20of the first conveyor system10can move under the pallets50whilst they are still in the lorries48and bring them down from the lorries48. A conveyor unit20and a load carrier12which is brought together with this thereby form an assembly52, irrespective of whether or not the load carrier12is equipped with material to be conveyed14. An assembly52of this type is again shown separately inFIGS. 6 and 11, in which it is made clear that the conveyor device18is part of an assembly52of this type. InFIGS. 7 to 11, a respective assembly52is otherwise no longer provided with further reference numerals for the sake of clarity.

The conveyor device18receives the load carrier12in the manner described above and then conveys this as shown by corresponding arrows inFIGS. 6 and 7from the inbound delivery zone46into a second operating zone54which is shown inFIG. 7.

The second operating zone54in the present exemplary embodiment is a distribution zone56in which the material to be conveyed14is brought on the pallets50to different conveyor systems, i.e. to a second conveyor system58or a third conveyor system60in the present case, by means of which the material to be conveyed14is conveyed to a destination point.

A lift system62and an overhead track system64are shown inFIG. 7as examples of a second and a third conveyor system56,58. By means of the lift system62, the material to be conveyed can be conveyed for example to a further operating zone66which is located at a different level from the distribution zone56.

An assembly52moves independently into the lift system62here and is conveyed by this latter. The lift system62here can be constructed as a continuously running, so-called S-conveyor68, as is known per se. As a result of the conveyor device18in the assembly52, this can move independently into the S-conveyor68and out of this again on the upper level, or vice versa.

The precise construction of the overhead track system64is not important here; it can refer to any overhead track system for transporting pallets. Interacting with the conveyor devices18, the overhead track system64carries along a hanger70which provides a travelling surface71for the conveyor devices18.

As illustrated again by arrows, an assembly52can be received directly from the inbound delivery zone46by the overhead track system64or once the assembly52has already been conveyed by the lift system62.

The levels at which the assemblies52are shown in the figures do not correspond to the actual conditions. It goes without saying, for example, that, to receive or hand over an assembly52, the travelling surface71of the hanger70has to be located at a level at which the assembly52can move directly into or out of the hanger70without limitation.

To this end, it is possible to provide various active and/or passive means for altering the level. The alteration can therefore take place in that an assembly52which normally moves on a warehouse floor travels over a ramp to a level which enables it to move into the hanger70. The hanger70can alternatively or additionally be lowered from its normal conveying level by altering the rail accordingly or by means of active lifting devices, in which case pits may be required. It is also possible to use smaller lifting platforms for altering the level. The same applies for all other conveyor systems.

InFIGS. 8 and 9, a storage zone74is shown as a fourth operating zone72;FIG. 8shows an entry region76andFIG. 9shows an exit region78of the storage zone74.

The storage zone74is conceived for example as a high rack80in which movable storage and retrieval systems84operate as a fourth conveyor system82of the logistics system44to move the pallets50with the material to be conveyed14between different tiers of the high rack78and the floor level, as is known per se. A lift system is generally likewise formed by the storage and retrieval systems84.FIGS. 8 and 9show three tiers, which are not provided with a specific reference numeral.

The conveyor devices18arrive as an assembly52in the storage zone74and can position the load carriers12on a particular storage level. The conveyor devices18can then part with the load carriers12and either exit the storage zone74or, with another load carrier12, form another assembly52which is to be removed from the storage area. Therefore, pallets50with material to be conveyed14, for which no conveyor device18of the first conveyor system10is allocated, are deposited in the different tiers.

In a storage zone74of this type, the conveyor devices18can therefore hand over the load carriers12with the material to be conveyed14to the storage and retrieval systems84, or accept the load carriers12with the material to be conveyed14from the storage and retrieval systems84and be conveyed along by these latter as an assembly52.

As an example of a fifth operating zone86of the logistics system44,FIG. 10now shows an order picking zone88in which the material to be conveyed14, which is deposited on the pallets50, is picked. To this end, the load carriers12are conveyed from the exit region78of the storage zone74into the order picking zone88, for which the overhead track system64is used again, for example. A further S-conveyor68is shown again by way of example in the order picking zone88itself.

As shown inFIG. 10, an assembly52reaches an order picker90from the storage zone74. This means that the conveyor device18also has to be conveyed by the overhead track system64and the S-conveyor68in the region of the order picking zone88.

The order picker90redistributes material to be conveyed14on load carriers12which then arrive as an assembly52at an outbound delivery zone92shown inFIG. 11, which, in the present exemplary embodiment, therefore forms a sixth operating zone94of the logistics system44. The conveyor devices18of the first conveyor system10themselves serve again as conveying means here; an assembly52is not moved by another conveyor system. The conveyor devices18can move with the pallet50and the material to be conveyed14into a lorry48, deposit the pallet50there and move out of the lorry48, whereupon they can travel back to the logistics system44again.

In addition to the lift and overhead track systems62and64shown, it is alternatively or additionally possible for other conveyor systems to be present, which are well-established in a manner known per se and can convey a conveyor device18or an assembly52comprising a conveyor device18and a load carrier12. Special mention shall be made here to ropebelt, belt or chain conveyers, by which and on which pallets50can be moved. The conveyor devices18and assemblies52can be moved along by such conveyors.

It is to be understood that additional embodiments of the present invention described herein may be contemplated by one of ordinary skill in the art and that the scope of the present invention is not limited to the embodiments disclosed. While specific embodiments of the present invention have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying claims.