WO2020078602A1

WO2020078602A1 - Linear-motor-operated transport system having circular transport path, and operation of same

Info

Publication number: WO2020078602A1
Application number: PCT/EP2019/071792
Authority: WO
Inventors: Michael Neubauer
Original assignee: Krones Ag
Priority date: 2018-10-17
Filing date: 2019-08-14
Publication date: 2020-04-23
Also published as: DE102018217777A1

Abstract

The present invention relates to a transport system for transporting piece goods and to a method for operation same, the transport system comprising a substantially circular transport path having at least one long stator (285) of a linear motor and at least one guide element (280) and a plurality of individually controllable transport elements (270), which are mounted movably on the at least one guide element (280), the at least one guide element (280) and/or the at least one long stator (285) being designed so as to be rotatable about a rotation axis that extends through the centre point (264) of the transport path.

Description

Linear motor-operated transport system with a circular transport path and operation of the same

Field of the Invention

The present invention relates to a transport system and a method for transporting piece goods, in particular containers, with an essentially circular transport path.

State of the art

Transport systems with a linear motor drive, in particular long-stator linear motors, are well known in the prior art and are increasingly being used industrially for the transport of piece goods, for example containers.

A common feature of the transport systems with linear motor drive is that specially designed transport elements, so-called runners, movers, shuttles or pucks, are moved with the long stators or stators of one or more linear motors along a transport path, in particular along one or more guide rails . The transport elements are often used in particular to transport objects such as general cargo, in particular containers, preforms or containers, along the transport path. The transport along the transport path can serve, for example, the transport between treatment machines or the transfer between two transport devices.

Examples of treatment machines are a filling machine in the beverage processing industry, with which containers transported with the transport elements are filled, for example, with a liquid product. Other examples are given by a labeling machine, a direct printing machine or a blow molding machine. Such machines are often designed as so-called rotary machines. As mentioned, transport systems with a linear motor drive can also be used to transfer the transported objects between an incoming flow of the objects and an outgoing flow of the objects. The divisions of the incoming and outgoing stream can in particular be different, with the linear motor guaranteeing a synchronous takeover of the objects from the incoming stream and a synchronous transfer of the objects to the outgoing stream.

The division or the separation distance of a stream of objects is to be understood here and in the following as the distance between corresponding points of successive objects. When conveying the objects on a circular path, an angle division can also be defined, as described in more detail below. There is a clear connection between the individual divisions, so that relations with regard to a division imply corresponding relations with respect to an alternative definition of the division.

If, for example, a container treatment system is to process different container formats, the situation arises in some cases that in a machine of the system arranged upstream in the production flow, for example a blow molding machine for forming the containers from a preform, depending on the operating mode (ie depending on Container format) differently many of the processing stations, for example blowing stations of the blow molding machine, are used, for example each station in a first operating mode and only every second or every third in a second operating mode. If, for example, only every second processing station is used on a machine, it is said that it runs with half the load.

Typically, a division change star is provided which is designed in such a way that, in an operating mode, for example with a full load, it brings the containers to the division which is required for the subsequent machine (when this machine is fully loaded). However, if the upstream machine is to be operated with half the load and the division change star continues to be used unchanged, gaps arise in the container flow which continue across the division change star into the downstream machine, so that not all stations in this machine then either are occupied.

These gaps can only be closed if a suitable division change star is used for each operating mode. For example, the division change star must bring about a smaller division change for a full load than for a half load. For this reason, the division distance must also be different in different areas of the division change star for different operating modes. In order to change the division distance of a division change star, for example for a format change, it has hitherto been known to exchange the curve guidance, often in the form of a cam disc, of the division change star and / or to adapt the number of gripping elements. This means that a complex conversion is necessary, which also results in a relatively long service life for the system. In addition, a separate cam is required for each operating mode, which leads to high acquisition costs. In order to remedy this problem, it is conceivable to replace the pitch change stars generally used in the prior art with a transport system with a linear motor drive.

The transport elements can be moved individually and independently of one another by means of electromagnetic forces via the stator. The transport elements are often mounted on rollers or roller bearings, more rarely on plain bearings, on one or more running rails as guide elements, which essentially follow the course of the long stator.

As described in more detail below, one or more magnets are located on or on the transport elements, which interact with the magnetic field generated by the stator and are moved in this way. Depending on the design of the linear motor in question, different forces and moments act on a transport element. For example, normal forces act due to the magnetic attraction between the secondary part of the transport element and the long stator. If the transport path is curved, outward centrifugal forces act. Weight forces act in particular when the transport elements are loaded with a payload in the sense of the transported object. Finally, depending on the desired time-distance profile, acceleration and deceleration forces act on the transport elements. In addition, due to a cantilevered object, torques can also act on the transport elements.

These forces and moments must be absorbed by the storage of the transport elements, for example by the rollers. For this reason, the rollers are subject to more or less severe wear. Since the bearings with which the transport elements are mounted on the conveyor track represent the only component that is subject to wear in a long-stator linear motor, the maintenance intervals of the entire transport system are essentially determined by the service life of the rollers. By increasing the service life of the rollers, the machine downtime can be reduced through longer maintenance intervals. There are also cost savings, as new roles are rarely required.

Compared to rotary machines, a machine structure with a transport system with a linear motor drive has the disadvantage that each transport element has to be stored separately via its own bearings, for example its own rollers. In order to achieve a comparable production output of the machine, the transport elements have to move along the transport path at a relatively high speed. As a result, the roles of the transport elements achieve enormous mileage within a very short time. For example, the annual mileage of the rollers of the transport elements with a contemporary output of the Machine can be several 10,000 km. Due to the high loads caused by the forces and moments that occur and the high mileage, the rollers are subject to high wear.

In addition, there is considerable waste heat that has to be dissipated in the magnetic interaction between the secondary parts of the transport elements and the long stator, for example through dissipation of induced currents. The greater the accelerations and speeds that occur or are required in the transport process, the greater this waste heat. It is often difficult to dissipate the waste heat, particularly in the case of compactly designed devices.

It is therefore the object of the present invention to provide a transport system and a method for transporting piece goods, in particular containers, which avoid the disadvantages described above. In particular, the wear of the bearing elements of the transport elements is to be reduced and the maintenance interval of the transport system is to be extended. In general, the present invention is based on the object of reducing the maintenance costs and increasing the output of the corresponding machine. In addition, the present invention has for its object to reduce the waste heat generated during transport. Finally, the object of the present invention is to ensure a greater flexibility of container treatment plants with regard to the spacing between the parts, and in particular to simplify the changeover to another parting distance and to extend the service life.

Description of the invention

The above-mentioned objects are achieved by a transport system for transporting piece goods, in particular containers, comprising: an essentially circular transport path with at least one long stator of a linear motor and at least one guide element; a plurality of individually controllable transport elements, which are movably mounted on the at least one guide element, the at least one guide element and / or the at least one long stator being designed to be rotatable about an axis of rotation through the center point of the transport path.

The transport elements are used for the transport of piece goods and can, for example, each be loaded with at least one container. For this purpose, the transport elements can accordingly designed holding or gripping elements. For the sake of simplicity, the following will speak of loading with containers. However, it goes without saying that this also encompasses other objects.

Containers are in particular beverage bottles, but also other containers for food, medicines, hygiene articles, cleaning agents or the like, such as. B. cans, glass bottles or other glass containers with lids, packaging based on cardboard or composite materials, Tetrapack or the like. Intermediate products, in particular preforms for stretch blow molding the containers, are also conceivable for containers made of plastic. Furthermore, containers are also to be understood to mean assembled containers with several containers.

Long stator linear motor systems are well known in the prior art, so that a detailed description is not given here. Such a linear motor system has a large number of transport elements which can be designed as a runner, puck, slide, shuttle or the like, which can be moved along the transport path by interaction with at least one linear motor train of the linear motor designed as a long stator. The transport elements can be individually controlled via a control unit, whereby each transport element can be accelerated, decelerated, moved at a constant speed or even stopped at times on the transport path as required. The individual controllability of the transport elements results in a variable movement profile for each individual transport element.

As is known, the driving of the transport elements along the transport path takes place in the linear motor drive by magnetic interaction between at least one secondary part of the transport element and the at least one long stator of the long stator linear motor. The secondary part of a transport element designates the subunit of the transport element, to which a force for moving the transport element is exerted by magnetic interaction with corresponding interaction elements of the long-stator linear motor. To move the transport elements in a targeted manner, the long stator linear motor can have a large number of electrical windings arranged along the respective long stator in the form of electromagnets which can be controlled individually or in blocks. Here, more complex designs are also conceivable, for example by means of a Haibach arrangement of the electromagnets for amplifying the magnetic flux on the side facing the secondary part of the transport element. For the magnetic interaction with the at least one long stator, at least one sequence, that is to say a sequence in the longitudinal direction of the transport element, of generally adjacent permanent magnets and / or electromagnets, in particular non-switching electromagnets, with alternating polarity is attached to the secondary part, which can be formed, for example, in the form of a carrier plate. Depending on the design and arrangement of these magnets, and depending on whether a single-sided or double-sided linear motor drive is used, the transport elements can also have two or more secondary parts. For example, a separate secondary part can be provided for each long stator. To simplify the illustration, transport elements with exactly one secondary part are assumed here and below without restriction.

The at least one long stator of the long stator linear motor can in particular be designed as a synchronous linear motor, since in general no slip occurs in the synchronous linear motor, so that the movement of a transport element with a predetermined movement profile can be carried out more easily by the control unit. In an alternative embodiment, the at least one long stator can also be designed as an asynchronous linear motor, the transport element being an electrically conductive element, e.g. B. in the form of a metallic plate on which additional permanent magnets and / or non-switching electromagnets can be attached, for induction by the asynchronous linear motor. For the magnetic interaction with the at least one long stator, the transport elements, as mentioned, can each have a secondary part, which is equipped with at least one sequence of permanent magnets and / or electromagnets, hereinafter referred to as magnets of the secondary part, wherein the secondary part is designed in such a way that the respective transport element can be moved along the transport path by magnetic interaction with the at least one long stator of the transport path.

The transport element can be designed as a passive transport element which is moved via a secondary part with at least one sequence of permanent magnets and / or non-switching electromagnets by interaction with the electromagnetic alternating fields generated by the individually controllable electromagnetic magnets of the linear motor. A non-switching electromagnet is connected to a power supply and / or a control unit of the transport system in such a way that a preferably controllable electrical current flows through it in the same direction. A transport element with a secondary part with an electrically conductive element for induction by an asynchronous linear motor is also referred to as a passive transport element. Alternatively the transport element can be provided as an active transport element with electrical windings, ie a sequence of switching electromagnets, which can apply the alternating magnetic fields necessary for the drive. Accordingly, the at least one long stator of the transport path in this development is provided with permanent magnets or non-switching electromagnets. For the sake of simplicity, only the design of the long-stator linear motor drive with passive transport elements is dealt with below. Unless expressly stated otherwise, the invention can also be applied to active transport elements by controlling the electromagnets of the secondary part accordingly.

In order to move a (passive) transport element with a desired movement profile along the transport path, the control unit controls the coils of the long stator individually or in blocks via a corresponding voltage or current pulse, as is generally known in the art. In order to generate a force required for the movement profile, for accelerating the transport element, for overcoming a frictional force during constant travel, or for braking the transport element, by means of the magnetic interaction, the coils in the region of the transport element are loaded with an appropriate load voltage or respectively energized with a corresponding load current. For example, the movement of the transport element can be controlled by a three-phase voltage pulse on the coil or coils, the voltage pulse being moved on with the transport element. The phase depends on the current and the desired position of the transport element.

The pulse of the control voltage or the control current generated by the control unit is converted by means of an amplifier into a corresponding load voltage or a corresponding load current on the coil or coils. For this purpose, the control unit can have, for example, a servo amplifier or servo controller, which converts the low control voltage to the required higher load voltage. Due to the inductances of the coils used, the actual load current in the coils, and thus the force acting on the transport element, generally lags behind the control voltage or the control current. In addition, unknown influences occur during the movement of the transport element, which lead to a deviation of the actual movement of the transport element from the movement profile specified by the control unit. Such influences are present, for example, due to the friction occurring and the rotation of the guide element and / or long stator described below. In order to keep the resulting positioning error, ie the deviation of the actual position of the transport element from the desired position due to a predetermined movement profile, as low as possible, the transport system, as is generally known in the prior art, can regulate the control voltage / control current or the load voltage / the load current by means of feedback from a position detection device and / or speed detection device of the transport system. The position detection device measures the actual position of the transport element and returns it to the control unit as feedback. On the basis of the actual position and optionally an actual speed of the transport element detected by the speed detection device, the control unit can adapt the control voltage or the load voltage accordingly. Control units for controlling the control voltage or the load voltage of long stator linear motors, for example using a PID controller, and position and / or speed detection devices for long stator linear motors are generally known in the prior art and are therefore described here not described in detail.

According to the invention, the transport path of the transport system is essentially circular. An essentially circular shape of the transport path is to be understood as being circular within the manufacturing tolerances. The circular shape of the transport path also means that the transport elements move in one plane. In other words, the transport elements move on a circular path. However, this does not rule out the fact that the transport track also includes one or more branches in the form of switches which enable individual transport elements to be discharged or introduced.

According to the invention, the transport path comprises at least one of the long stators described above. The at least one long stator is arranged essentially parallel to the transport path and is therefore also essentially circular.

Furthermore, the transport track has at least one guide element, for example a guide rail, on which the transport elements are movably mounted by means of one or more bearing elements. In particular, the transport track can run two parallel guide rails in the form of a double rail system, such as. B. on railroad tracks. The one or more long stators can be arranged parallel to the respective guide rails, for example in the middle between them. A large number of designs of the guide elements and long stators is known in the prior art. For circular Movement of the transport elements, the at least one guide element is thus also essentially circular.

In particular, the transport path, the at least one long stator and the at least one guide element according to the present invention are arranged concentrically around the center of the transport path in the plane of movement of the transport elements.

The shape and cross section of the guide elements are arbitrary and are determined only by the design of the transport elements and the bearing elements of the transport elements with which the transport elements are movably mounted on the guide elements. For example, a guide rail can have a guide channel in which a guide pin of the transport elements is guided and / or a wheel flange on which one or more suitably arranged guide rollers of the transport elements roll. A variety of alternative embodiments, e.g. B. by means of a plain bearing, is conceivable here. The provision of guide rails on the transport path enables a low-friction movement of the transport elements along the transport path. In addition, the transport track and / or the guide elements can have a running surface on which corresponding support elements, for. B. casters, roll or slide.

According to the present invention, the at least one guide element and / or the at least one long stator is designed to be rotatable about an axis of rotation through the center of the transport path. The axis of rotation passes through the center of the circle formed by the transport path or the movement of the transport elements along the transport path. Since the at least one guide element and the at least one long stator are also essentially circular, as mentioned above, and are arranged concentrically to the circle formed by the transport path, the at least one guide element and / or the at least one long stator are thus rotatable or rotatable formed around an axis through the common center. The axis of rotation is thus perpendicular to the plane in which the transport elements move along the transport path.

A rotatable design of the at least one guide element enables the at least one guide element to be rotated about the axis of rotation in the direction of the desired movement of the transport elements. As shown in more detail below, this rotation can be free or driven. By rotating the at least one guide element, for example a guide rail, in the running direction of the transport elements, the bearings, for example rollers, with which the transport elements are mounted on the guide element are relieved. Since the guide element rotates in the running direction, the Transport elements with respect to the guide element only cover the difference between their absolute movement profile and the rotation of the guide element. Due to the rotation, the guide element can lag behind or run ahead of the absolute movement profile.

Here and below, an absolute movement profile is to be understood as the movement profile of the transport elements, in particular their time-dependent angular position with respect to the center point of the transport path, in a reference system which is stationary with respect to the transport system and in particular a footprint of the transport system. A relative movement profile here and in the following, on the other hand, means the movement profile of the transport elements in a reference system which also rotates with the at least one guide element and / or at least one long stator. In particular, the relative motion profile in the form of the deviation, i.e. Difference between the time-dependent absolute angular position of the respective transport element and the time-dependent absolute angular position of a rotating reference point of the at least one guide element. In this case, positive angular differences express that the transport element leads the rotation of the guide element, while negative angular differences express that the transport element lags behind the rotation of the guide element.

Since the friction of the bearings due to the relative movement between the at least one guide element and the transport elements, i.e. by determining the relative movement profile, rotation of the at least one guide element in the running direction of the transport elements can result in a considerable reduction in the friction and thus in the wear of the bearings that occurs. If, for example, rollers are used as bearings, rotation of the guide element also reduces the roller speed of the rollers and thus the wear of the rollers. The direction of travel of the transport elements is usually fixed as a function of the arrangement of the transport system relative to the entire system. Due to the reduced friction and wear, the service life of the transport system increases, and with it the service life of the entire system. Maintenance costs are also reduced because the bearings do not have to be replaced as often.

Regardless of whether the electromagnetic fields are generated for the interaction of electromagnets of the long stator or electromagnets of the transport elements, generated by the alternating magnetic fields due to the switching of the coils of the electromagnet waste heat, which must be derived from the components of the transport system, especially the long stators.

Due to the rotation of the at least one long stator in the running direction of the transport elements, the frequency with which the coils of the long stator or of the secondary part of the transport element change their polarity can be reduced, since this change only has to cause the relative movement profile. For example, at the points on the transport path at which the long stator rotates with the desired movement of the transport elements, it is not necessary to change the polarity of the coils of the long stator or secondary part. For this reason, the ohmic losses in the coils are reduced, so that less waste heat occurs.

The electromagnetic traveling fields of a long stator linear motor also cause induction currents in coils and electrically conductive parts of the transport elements and long stators, the dissipation of which leads to heat generation. The greater the field strength of the electromagnetic traveling fields or the greater the forces generated by the electromagnetic interaction, the greater the induced currents and the heat generated with them. In other words, there is increased heat generation, especially at high accelerations, which must be derived from the components of the transport system. In addition to accelerations of the transport element, the force required to overcome the friction and the friction itself are a source of waste heat.

When the at least one guide element rotates in the running direction of the transport elements, the friction is reduced, as described above, and thus also the force required to overcome the friction. Thus, a common rotation of the guide element and the long stator additionally reduces the waste heat that occurs and is to be dissipated. Since less waste heat occurs, the linear motor-operated transport system according to the present invention can be made more compact than comparable transport systems, so that installation costs in particular can be saved.

Even in the case of a rotatable guide element and / or rotatable long stator, the desired absolute movement profile of the transport elements can be generated by specifically controlling the electromagnets of the long stator or the transport elements. For this purpose, in particular, as is known in the prior art, a position detection device can be provided for detecting the position of the respective transport element along the transport path. Position sensing devices are well known in the art. For example, sensors can be arranged along the transport path, which are designed to determine the position and / or speed of a transport element in the area of these sensors. The sensors can be designed as an optical sensor, an electrical sensor, an electromagnetic sensor or a mechanical sensor, for example by measuring a light reflection on a reflector element of the transport element, by induction of an electromagnetic signal due to the movement of the transport element, by changing the electrical resistance of the sensor using a magnetoresistive effect, for example due to a magnetic flux change caused by the movement of the transport element comprising a magnetic reference element, or by local pressure measurement based on the weight of the transport element, the position of the transport element can be determined. An electromagnetic sensor can also be designed as a Hall sensor. Hall sensors, for example, allow a transport element to be located with an accuracy of 0.2 mm to 1 mm. Magnetostrictive displacement sensors can also be used as sensors, which determine the position of the transport element with the aid of magnetostriction. A waveguide made of a magnetostrictive material, through which a conductor is threaded, is arranged along the measuring section as the measuring element. A permanent magnet suitably arranged on the transport elements leads as a position transmitter to the magnetostriction of the waveguide, which generates a mechanical wave that spreads to both sides. The position of the transport element can be determined from the propagation of the shaft.

Other possible sensors are proximity sensors of an inductive or capacitive type which are regularly arranged on the transport track, and incremental sensors designed as linear or rotary sensors or absolute value sensors. With incremental encoders, it may be necessary to first determine the absolute position of the transport elements when starting up the transport system by means of a reference run. Inductive sensors can also be used to deduce the speed of the transport element from the amplitude of the induced current pulse or voltage pulse. The speed of the transport element can also be determined from the measurement data from incremental sensors.

The positions and / or speeds of the transport elements detected by the sensors of the transport elements and / or the long stator linear motor or the transport path are forwarded via corresponding radio antennas or signal lines to the control unit of the transport system, which unit controls or regulates the Transport systems processed. The sensors can be arranged along a rotationally fixed part of the transport path and / or along a part which also rotates with the at least one long stator. In the latter case, the control of the long stator for generating the relative movement profile is simplified. In the first case, the control of the long stator for generating the absolute movement profile is simplified.

Devices and methods for position detection and for controlling a long stator of a linear motor to generate a desired movement profile are described, for example, in US patent application US 2003/0230941 A1. A control and / or regulating unit of the transport system, for example in the form of a programmable logic controller, detects the absolute and / or relative position of each transport element via a position detection device and, as described above, controls the individual electrical windings of the long stator in accordance with the desired absolute or relative motion profile. In addition to the position detection, the speed of the transport elements can also be recorded via the sensors and incorporated into the control. Furthermore, sensors, for example rotary encoders, can be provided which detect the rotation of the at least one long stator. The angular position of the elongated stator and thus optionally its angular velocity can be taken into account by the control and / or regulating unit of the transport system when activating the coils of the elongated stator in order to generate the desired movement profiles. The control and / or regulating unit can control the long statator or stators in such a way that the transport elements receive containers at a receiving point of the transport path synchronously with a container inlet and at a delivery point of the transport path release them synchronously with a container outlet. In between, the transport elements can be accelerated and / or braked in order to achieve a corresponding adaptation of the speeds between the receiving point and the delivery point.

According to a further development, the transport system can comprise at least one motor, in particular a servo motor, which is designed to rotate the at least one guide element and / or the at least one long stator about the axis of rotation. The at least one motor thus drives the rotation of the guide element and / or the long stator. A common motor can be provided to drive a common rotation of the guide element and long stator, so that the guide element and long stator rotate synchronously. Alternatively, separate motors can be provided for driving the rotations of the guide element and the long stator. For example, it may be desirable for the guide element to rotate relative to the long stator in order to generate a desired acceleration or deceleration relative to the long stator via the friction. For example, a drive of the guide element at the higher speed can be provided for an inlet star that picks up containers from an incoming stream at a low speed and transfers them to a subsequent rotary machine at a higher speed, while the long stator is driven at the lower speed. The occurring friction between the guide element and the bearing of the transport element thus accelerates the transport elements and thereby relieves the acceleration forces to be applied by the long stator.

However, only one motor can be provided, which either drives the guide element or the long stator.

According to a special development, the transport system can comprise a control and / or regulating unit which is designed to control and / or regulate the at least one motor in such a way that a rotational speed of the guide element and / or the long stator is between a minimum speed and a maximum speed of the transport elements. In order to reduce the occurring friction between the guide element and the bearings of the transport elements as efficiently as possible, it makes sense to drive the guide element with a rotational speed, that is to say an angular speed, which lies between the minimum and maximum angular speed of the transport elements. Here and below, the angular velocity of the elements mentioned always relates to the center of the circle of the transport path.

It also makes sense to drive the long stator by means of a motor in such a way that the angular speed or rotational speed of the long stator lies between a minimum and a maximum angular speed of the transport elements. In this way, the switching frequency of the coils of the long stator is reduced, as described above, and thus the waste heat that occurs. The minimum and maximum speed of the transport elements can be predetermined, for example, by the speeds of an incoming and outgoing container flow. When the containers are handed over to a rotary machine, the speed of the handover is generally a minimum or maximum speed at which the transport elements are to rotate around the transport path. According to a further development, both the at least one guide element and the at least one long stator can be designed to be rotatable, the guide element being designed to rotate relative to the long stator. In other words, the guide element and the long stator can be mechanically connected to one another in such a way that they always rotate together. If more than one guide element and / or more than one long stator are provided, a mechanical connection of the guide elements to one another or of the long stators to one another can be provided in a very general way according to the present invention such that the guide elements or the long stators always rotate together . In this way, the drive of the respective rotation can be simplified by providing only one motor. A rotationally fixed connection between the guide element and the long stator makes it possible to drive both elements together with a single motor, and thereby simplifies the required control and / or regulation.

According to an alternative development, the at least one guide element can be freely rotatable. A freely rotatable bearing means that we at least one guide element is not driven by a motor. Rather, the guide element can be mounted in such a way that it can rotate as freely as possible relative to other components of the transport system, in particular to the at least one long stator. As a result of this freely rotatable mounting, the guide element is automatically carried along by the rotating transport elements due to the friction, so that there is no need to separately drive the rotation of the guide element. Together with a fixed long stator, this results in a considerable extension of the service life of the bearings of the transport elements with minimal design effort.

According to a development, the number of transport elements mounted on the at least one guide element can be greater than the quotient from 2p and the maximum desired angular division of the transport elements between a receiving point and a delivery part for the piece goods along the transport path. As already mentioned, the transport elements transport the piece goods, in particular the containers, from a receiving point arranged on the circumference of the transport track to a delivery point arranged downstream on the circumference of the transport track. The transport elements cover an angular area of the transport path that is less than 2p. In this angular range, the transport elements are conveyed at a mutual angular distance, which is referred to as the angular division of the flow of the transport elements. Depending on the use of the transport system, there are, as already indicated several times, requirements both for the angular speed of the transport elements in the area of the receiving and delivery points and for the angular division in these areas. For example, the arrangement of gripping elements, for example neck handling clamps, of a downstream filling machine specifies an angular division of the transport elements when containers are transferred to the filling machine at the delivery point. The transport elements can thus preferably be moved in the angular range covered by you after an initial acceleration phase with this angular division.

The partial circle of the transport path between the delivery point and the receiving point serves to return the transport elements and can therefore be regarded as a return path. An angular range other than zero is also assigned to this return path. In order to be able to guide the transport elements along the return path with an angular velocity that is as optimal as possible with regard to the friction that occurs, the number of transport elements mounted on the guide element is greater than the quotient of 2p and the maximum in the actual transport path of according to the present development Pick-up point chosen for delivery point. In this way, an excessive acceleration of the transport elements along the return path as well as a backlog of excess transport elements at the receiving point can essentially be avoided.

As already mentioned several times, the transport elements can be mounted on the guide element via one or more rollers. Due to the rotatable design of the guide element, the mileage of these rollers is considerably reduced, so that they have to be replaced much less frequently.

According to a further development, at least one motor for driving the at least one guide element and / or the at least one long stator can be designed as a torque motor, in particular as an external rotor. Brushless electric motors with a hollow shaft are referred to here and below as a torque motor. In particular, this includes brushless motors whose rotor is equipped with permanent magnets. In the case of an external rotor, the rotor is also arranged outside the stator, so that the rotor driven by the electromagnets of the stator rotates around the stator. In the case of an inner rotor, on the other hand, the stator surrounds the inner rotor. According to this development, the at least one motor is designed as a torque motor. At least these are tion element and / or the at least one long stator mechanically connected to the rotor of the torque motor in such a way that they also rotate with the rotor. Thus, the at least one guide element and / or the at least one long stator according to this development are designed as part of the rotor of the torque motor.

In order to be able to continue to refer to the function and design of the long stator of the linear motor drive of the present invention, the present description always speaks of a long stator, even if it is circular and rotates about the axis of rotation. The term long stator is therefore to be understood in relation to the movement of the transport elements and not to a fixed reference system. In contrast to this, the stator of the torque motor is arranged stationary in the reference system of the transport system, so that the terms stator and rotor are used in connection with the torque motor in accordance with their usual meaning.

According to a special development, the long stator can be designed as part of the torque motor, in particular driving the rotation of the long stator is at least partially effected by magnetic interaction between magnets of the long stator and magnets of the stator of the torque motor. In this development, the magnets of the long stator are thus themselves used for electromagnetic interaction with the stator of the torque motor. This further development can be used particularly effectively if the transport elements are to maintain a constant speed during their entire circulation, as would be the case, for example, when used as a rotary machine for a filling machine. Even when the transport elements are designed as active transport elements, so that the long stator is designed with permanent magnets or non-switching electromagnets, the magnets of the long stator can be reused for electromagnetic interaction with the stator of the torque motor. Finally, due to the generally high torque of a torque motor, it may also be sufficient if the electromagnets of the stator driving the rotor are only provided in a partial angular range. This can be selected, for example, in such a way that the transport elements are to be moved in this angular range at a constant angular speed corresponding to the rotational speed of the long stator or the rotor of the torque motor. The further developments described reduce the installation effort for the entire transport system. According to a development, the at least one long stator can be designed with a plurality of electrical windings in the form of electromagnets which can be controlled individually or in blocks. The electromagnets can be controlled via the control and / or regulating unit described above in such a way that a desired movement profile is generated by the electromagnetic interaction with the secondary parts of the transport elements. According to this development, the transport elements are thus designed as passive transport elements which interact with the alternating magnetic fields generated by the electromagnets of the long stator via permanent magnets and / or non-switching electromagnets and / or electrically conductive elements.

According to a special development, the linear motor can be designed as an asynchronous linear motor as described above. This is particularly advantageous in combination with a rotating long stator, since electrical currents are induced in an electrically conductive element of the secondary part of the transport elements simply because of the rotation of the long stator, which, based on Lenz's rule, the movement of the transport elements of the rotation of the Try to adjust the long stators. Thus, the coils of an asynchronous linear motor only have to be switched to achieve a movement profile of the transport elements that differs from the rotation of the long stator.

According to a further development, the transport system, and in particular the at least one guide element, can have a stabilization device against radial lifting of the transport elements when the long stator is switched off. As mentioned above, centrifugal forces acting radially outward act on the transport elements due to their movement along the transport path. In addition, torques act in particular on loaded transport elements, which can cause the transport elements to be lifted radially from the at least one guide element. In operation, these forces are compensated for by the electromagnetic attraction between the long stator and the secondary part of the transport elements.

However, if an error occurs during the operation of the linear motor, or if the linear motor is switched off for another reason, there is a risk that the transport elements will fall off the transport path due to the above-mentioned forces. To prevent this, the transport system can have a suitable stabilizing device which prevents the transport elements from being lifted radially from the transport path by more than a tolerance value even when the long stator is switched off.

A large number of further developments of such a stabilization device are conceivable. For example, the stabilization device can also be circular along the transport path or be formed along at least one guide element. For example, a groove, groove or groove curve can be provided along at least one guide element, in which a correspondingly designed bolt, pin or a roller of the transport elements rotates. The circumferential locking element of the transport elements can be arranged such that it is non-contact in operation in the stabilization device, for. B. the groove curve. If the long stator fails, however, the transport elements are prevented from lifting radially or falling off by the mechanical engagement of the locking element with the stabilizing device.

The at least one guide element itself can also serve as a stabilizing device if the transport elements are suitably designed. For example, the transport elements can have rollers arranged radially inside the guide element, which absorb the forces acting radially outwards. The aforementioned guide channel, in which a guide pin of the transport elements rotates, can also serve as a stabilizing device. Even a magnetic stabilization device, for example on the basis of suitably dimensioned and arranged permanent magnets in the region of the transport path, which interact with the secondary parts of the transport elements, is conceivable. The stabilization device is always designed in such a way that it compensates for any radial forces acting on the transport elements when the long stator is switched off.

The invention further provides a container treatment system with one of the transport systems described above, a first container treatment machine, in particular a blow molding machine, being arranged upstream of the transport system and a second container treatment machine, in particular a labeling machine and / or a filler, downstream of the transport system. is arranged, and wherein the linear motor is designed to adapt a movement profile of the transport elements when the division in the outlet of the first container treatment machine is changed such that the division can be maintained in the second container treatment machine. The container treatment machines can in particular be rotary machines. By using the transport system described above, changes in the division of the upstream container treatment machine can be flexibly compensated, so that the division of a downstream container treatment machine remains unchanged. This allows a particularly simple and uncomplicated change of format. In addition, the transport systems described can also be used to close a (regular) gap that may occur in the container flow using a linear motor. Finally, due to the individual controllability of the transport elements, the usual entry and exit stars can be dispensed with. so that a direct transfer or transfer from or to the respective container treatment machine is possible. However, the transport system can also be used with an outlet star provided between the transport system and the first container treatment machine and / or an inlet star provided between the transport system and the second container treatment machine.

The above-mentioned objects are also achieved by a method for transporting containers using one of the transport systems described above, which comprises the following steps: picking up containers by the transport elements at a container inlet on the transport track; Dispensing the containers from the transport elements to a container outlet on the transport track; and transporting the containers by individually controlled movement of the transport elements by means of the long stator linear motor from the container inlet to the container outlet, the at least one guide element and / or the at least one long stator during the transport of the containers in the same direction as the movement of the transport elements rotate the transport path.

Here, the same variations and developments that were described above in connection with the transport system according to the invention for the transport of piece goods can also be applied to the method for transporting containers. In particular, the containers are picked up at a receiving point on the circumference of the transport path by an incoming flow of containers by means of suitable holding or gripping elements of the transport elements, transported from the receiving point by means of the transport elements to a delivery point for the containers on the circumference of the transport path and from there Transfer transport elements to an outflowing container stream. Here, the transport elements are moved as described above by means of a control and / or regulating unit of the transport system via appropriate control of the long stator of the linear motor in accordance with individual movement profiles. The container inlet can be designed, for example, in the form of a conveyor belt for the containers. The container outlet can be provided, for example, by a rotary machine. In this case, the transport system acts as an entry star for the rotary machine.

According to the invention, the at least one guide element and / or the at least one long stator rotate during the transport of the containers in the same direction as the movement of the transport elements around the transport path. The rotation in the same direction reduces the relative movement of the transport elements with respect to the guide element and / or the Long stator, so that, as described above, there is a reduction in wear on the bearing elements of the transport elements and in waste heat. In addition, the operating noise is reduced because the rollers rotate more slowly.

According to a further development, the method can further comprise the controlled driving of the rotation of the at least one guide element and / or the at least one long stator by means of at least one, in particular controllable, motor, in such a way that the guide element and / or the Rotate the long stator at a constant angular velocity. The motors described above can be used for this. The motor can be regulated via the control and / or regulating unit of the transport system described above. As mentioned, the angular speeds relate to the center of the circle formed by the transport path. On the one hand, a drive with a constant angular velocity simplifies the control of the coils of the at least one long stator and, as described above, also reduces the wear on the bearing elements of the transport elements. If it is favorable for the travel profile of the transport elements, the guide element can also rotate with changing angular velocity.

As described above, the angular velocity of the guide element can be different from the angular velocity of the long stator. However, the two angular speeds can also be the same, for example in that the guide element is connected to the long stator in a rotationally fixed manner.

According to a special development, the constant angular velocity of the guide element and / or the long stator can lie in an interval which is limited by the angular velocity of the transport elements when the container is being picked up and the angular velocity of the transport elements when the container is being dispensed. When the transport system is used, for example, as a graduation change star or infeed star, the speed of the incoming containers is generally lower than the speed of the outgoing containers. Conversely, when the transport system is used as an outflow star, the speed of the incoming containers is generally higher than the speed of the outgoing containers. For the synchronous pick-up or delivery of the containers by or from the transport elements, the angular speed must therefore vary between the angular speed during pick-up and the angular speed during delivery. An optimal reduction in wear of the bearing elements and the waste heat thus results, if the constant angular velocity of the guide element and / or the long stator contributes a value between the angular velocity of the transport elements the pick-up and the angular velocity of the transport elements on delivery.

According to a special development, the constant angular speed with which the guide element rotates can correspond to the angular speed of the transport elements when the container is being dispensed. Irrespective of whether the angular speed of the transport elements when dispensing the container is greater or less than the angular speed of the transport elements when receiving the container, rotation of the guide element with the angular speed when dispensing the container has the effect that the friction occurring between the guide element and the bearing elements of the transport elements causes part of the required acceleration or deceleration of the transport elements. Thus, the acceleration or deceleration force to be applied by the long stator is reduced accordingly, so that the waste heat generated by the long stator is also reduced.

The invention also provides a method for operating the container treatment system described above, comprising the steps of: treating the containers in the first container treatment machine, in particular blow molding the containers, transferring the containers from the first container treatment machine to the transport system, in particular via a Outlet star, which is arranged between the first container treatment machine and the transport system, and transfer of the containers from the transport system to the second container treatment machine, in particular via an inlet star, which is arranged between the transport system and the second container treatment machine, the operation of the container treatment system at least one first operating mode, in which each treatment station of the first container treatment machine is occupied and comprises a second operating mode, in which not every, in particular only every nth, treatment station of the first Container treatment machine is occupied, where n is an integer greater than 1, in particular equal to 2, and the division in the second container treatment machine is the same for the first operating mode and the second operating mode.

As already mentioned, the use of the transport systems according to the invention makes it possible to dispense entirely with inlet or outlet stars. The container treatment machines according to this development are generally designed such that they have a plurality of identical treatment stations, for example along the circumference of a rotary machine, which carry out the same treatment steps, for example blow molding, on the containers or preforms. Only every second or third of these treatment stations would be operated, for example because a larger container format is being driven As mentioned above, gaps arise at the treatment stations of the downstream container treatment machine. However, the transport systems described can be operated in such a way that the gaps are moved together until they are handed over to the subsequent container treatment machine. This is easily possible due to the individual controllability of the transport elements. In this way, a full load of the subsequent container treatment machine is made possible even with half the load of the upstream container treatment machine, which increases the productivity of the block system. The transport system according to the invention can also be used to compensate for an undefined and / or irregularly occurring gap in the upstream machine (for example due to an error or a generated gap due to the removal of a defective container), so that the downstream machine is provided with containers without a gap becomes. This is particularly helpful with treatment machines that are synchronously blocked to form a block system, since such block systems can only “process” gaps with increased effort. For example, label delivery must be prevented if there is a gap. This is done, for example, by (mechanical) switching off the labeling unit at the time when a gap moves past the label delivery point. However, such a switching of the unit can cause problems and means at least increased construction effort or wear. The use of the transport system according to the invention therefore leads to a seamless supply of the downstream machines arranged downstream. If there is a gap in the container flow in the upstream machine, the transport elements are activated in such a way that no transport element is available for potential acceptance when the gap hits the transport system. Rather, the transport element is delayed in such a way that the next transport element is not available until the next container to be transferred to the transport system, and the gap in the container flow in the transport system is thus eliminated.

The described developments of the transport system and the method for operating the transport system reduce the relative movement of the bearing elements, for example rollers, of the transport elements with respect to the at least one guide element and therefore lead to less wear on the bearing elements. Due to the lower wear, the bearing elements have a longer service life, which in turn leads to shorter downtimes and maintenance costs for the transport system and the entire system. In addition, both the rotation of the guide element and the rotation of the long stator lead to a reduction in the development of heat in the long stator or in the secondary parts of the transport elements. However, less waste heat allows one more compact design of the transport system and thus extends the possible uses of the transport system.

Further features and exemplary embodiments and advantages of the present invention are explained in more detail below with reference to the drawings. It is to be understood that the embodiments are not exhaustive of the scope of the present invention. It goes without saying that some or all of the features described below can also be combined with one another in other ways.

Figure 1 shows schematically some possible uses of a transport system according to the present invention in a container treatment system.

Figure 2 shows a plan view of a transport system with a circular transport path according to the present invention.

FIG. 3 shows a three-dimensional view of the transport system of FIG. 2.

FIG. 4 shows a vertical cross section through the transport system of FIG. 3.

FIG. 5 shows a simplified three-dimensional view of the transport system of FIG. 3.

FIG. 6 shows an alternative development of a transport system according to the present invention.

Figures 7a and 7b show schematic views of a container treatment plant with different loads.

In the figures described below, the same reference symbols designate the same elements. For better clarity, the same elements are only described when they first appear. However, it goes without saying that the variants and embodiments of an element described with reference to one of the figures can also be applied to the corresponding elements in the other figures.

FIG. 1 schematically shows some possible uses of a transport system according to the present invention in a container treatment system for printing containers 110 in a plan view. The exemplary embodiment shown here with a rotary machine 100 as the central transport system is frequently used in container treatment devices in the beverage industry, but also in the cosmetics and hygiene sector. By means of a first transport system with a circular transport path according to the present invention, in the manner of an inlet star 150 at a receiving point A, containers 110 are picked up individually from a single-track container stream 140 by synchronous movement of the transport elements by means of a long-stator linear motor drive and become a delivery part B transported. As described above, the guide element and / or the long stator of the transport system 150 can rotate in the same direction as the movement of the transport elements about an axis of rotation 162. Due to the individual movement of the transport elements, the otherwise common one-piece screw can be dispensed with.

At the delivery point B, the containers are transferred from the transport system 150 used as an infeed star to transport elements 130 of a second transport system used as a rotary machine 100. In the non-limiting further development, the second transport system 100, shown as an example in FIG. 1 and designed as a rotary machine, has transport elements 130 which are arranged and moved at uniform angular intervals around the axis of rotation 160 of the transport system, each of which has a transport element 130 which can be rotated about a separate axis of rotation Can have container plate for receiving the container.

In the development shown in FIG. 1, the uniform angular spacings of the transport elements 130, in combination with their angular velocity, specify the angular velocity of the transport elements of the first transport system 150 and their angular division at the delivery point B. As shown in the figure, the transport elements 130 loaded with a container move in the direction of the arrow about the axis of rotation 160 of the rotary machine 100. The containers conveyed by the transport elements 130 are attached to a plurality of printing units 120a-e, which are located on the periphery of the rotary machine are arranged, led by. By means of one or more print heads of each printing unit, a printing section is printed on the respective outer surface of the container when the containers carried along are passed. The printing units 120a-e can use the same printing section with different colors, e.g. B. yellow, magenta, cyan and black, or print different printing sections with the or the respective colors. In addition, the last printing unit 120e can apply a sealing or cover layer in order to protect the printed image from external influences. Furthermore, a curing station 125 for fixing the printed image is arranged on the periphery of the rotary machine.

It goes without saying that the printing device described here is only one example of the use of the linear motor-driven transport system in the manner of a rotary machine. Other possible uses arise, for example, in a blow molding device or Filling machine. In principle, the transport system according to the invention can be used in any type of process plant in which the transported piece goods are to be conveyed along a circular path.

Following the curing process at the curing station 125, the containers are individually transferred to a third transport system according to the present invention in the manner of an outlet star 155, which in turn forwards them to an outlet stream 145. The third transport system 155 has a multiplicity of transport elements which, by individual control, receive the containers synchronously from the transport elements 130 of the rotary machine 100 at a receiving point C. The containers are then transported in the direction of the arrow to the delivery point D, where they are again delivered synchronously to a single-track outlet stream 145. In the third transport system 155, too, the guide element and / or the long stator can rotate in the same direction as the transport elements move about the axis of rotation 164 through the center of the circle of the transport path.

A combination of transport systems according to the present invention with linear motor drive and known transport systems is also possible. For example, the inlet star 150 and the outlet star 155 can be designed with linear motor-driven transport systems, while the rotary machine 100 is designed as a container table with a central drive motor. A variety of other possible uses are conceivable for the transport systems according to the present invention.

Figure 2 shows a plan view of a transport system with a circular transport path according to the present invention. FIG. 3 shows a three-dimensional view of the transport system of FIG. 2. FIG. 4 shows a vertical cross section through the transport system of FIG. 3. Finally, FIG. 5 shows a simplified three-dimensional view of the transport system of FIG. 3.

In the exemplary, non-limiting further development shown in FIGS. 2 to 5, containers 110 are conveyed between a receiving point C and a delivery point D by means of a linear motor-driven transport system with a plurality of transport elements 270. In the embodiment shown, the transport elements 270 have holding elements 272, as shown, for example, in FIGS. 3 and 5 in a three-dimensional view, which hold the containers exemplarily shown as bottles 110. In the non-limiting further development of Figures 2 to 5, the container 1 10 on a sliding plate pushed upright from the pick-up point C to the discharge point D by means of the transport elements 270. An outer guide element 290 is provided as shown in FIG. 2 in order to prevent the containers from slipping out of the holding elements 272.

As can be seen in FIG. 2, the containers 110 are taken over by the transport elements 270 at the receiving point C with an initially larger angular division δ max, for example by the rotary machine 100 from FIG. For delivery to the outflowing container stream 145, this initial angular division is reduced to a smaller angular division during transport by the transport elements to the delivery point D, as can be seen in the top view in FIG. This is done by individual movement profiles of the transport elements 270, which are made possible by the linear motor drive according to the present invention. In this way, there is no need for a (one-piece) screw in the inlet and at the outlet.

As can be seen from the top view in FIG. 2, the transport path of the transport system is circular. The center of rotation 264 of this circle accordingly runs the axis of rotation for the guide rail 280 shown in FIGS. 3 to 5 and for the long stator 285 shown in FIGS. 3 and 4. The axis of rotation in the three-dimensional view of FIG. 3 is as a dashed line L. shown. Since the guide rail 280 and the long stator 285 are also circular and are arranged concentrically with respect to the transport path, the guide rail 280 and the long stator 285 have a common rotational axis L.

As can be seen in particular in FIGS. 3 and 5, the transport elements 270 are movably mounted on the guide rail 280 via rollers 274. As shown, the rollers 274 can have a concave rolling profile which is in engagement with a correspondingly convex track flange of the guide rail 280. In the development shown here, the transport elements 270 each have three rollers 274, which engage on both sides of the guide rail 280. In addition to the holding elements 272, secondary parts 276 are provided on the transport elements 270, in particular on a vertically aligned segment of the transport elements, the magnets of which interact with the magnets of the long stator 285. As can be seen from FIGS. 3 and 5, the special arrangement of the secondary parts of this development is such that the secondary parts 276 run around the outside of the long stator 285. However, it goes without saying that the present invention is not restricted to this arrangement of secondary parts and long stator, but also to internal ones Secondary parts and combinations of inner and outer secondary parts as well as inner and outer long stators can be used. In particular, several guide rails and / or several long stators can be provided. These only have to be arranged parallel to one another and concentrically. The secondary parts can also be arranged horizontally, that is to say in the plane of movement, and interact with appropriately aligned long stators.

In the special development shown, the long stator 285 is arranged in a rotational test via the brackets 286 shown in FIGS. 3 and 4. In this non-limiting further development, the long stator is therefore not designed to be rotatable. As described above, however, the long stator can also be designed to be rotatable.

In contrast to this, as shown in particular in FIG. 5, which shows a simplified three-dimensional view of the transport system without the long stator and the holder of the long stator, the guide rail 280 is connected to a controllable motor 282 via spokes and a shaft and is therefore designed to be rotatable. The motor 282 is controlled in such a way that it drives the guide rail 280 in the same direction as the movement of the transport elements 270, that is to say in the direction of the arrow shown in FIG. Thus, the transport elements 270 and in particular their rollers 274 only have to cover the difference between the rotational movement of the guide rail 280 and its absolute movement profile.

For this purpose, the magnets of the long stator 285 or the secondary parts 276 are controlled by means of a control and / or regulating unit 283 in such a way that the transport elements 270 are moved relative to the guide rail 280 with the desired relative movement profile. In this way, the running performance of the rollers 274 is reduced compared to the guide rail 280 by the rotational movement of the guide rail, so that there is significantly less wear on the rollers.

In the special configuration of FIG. 2, in which the linear motor-driven transport system picks up the containers, for example, at a higher angular speed at the receiving point C and delivers them at a lower angular speed at the delivery point D, the guide rail 280 can be moved by means of the motor 282, in particular at the angular speed be driven at the delivery point D. In this way, the transport elements 270 experience a deceleration due to the friction between the rollers 274 and the slowly rotating guide rail 280, which supports the deceleration forces to be applied by the long stator 285. As can be seen in FIG. 2, the transport elements 270 between the pick-up point C and the discharge point D have a maximum angular division δ max. If the number of transport elements 270 mounted on the guide rail 280 is selected to be greater than the quotient 2u / ö max, then a favorable angular division of the transport elements 270 along the return path between the delivery point D and the receiving point C can be selected. The movement profiles of the transport elements along the return path can be selected correspondingly cheaply, so that the smallest possible relative movement of the transport elements with respect to the guide rail 280 can also be set along the return path. This minimizes the friction of the rollers 274 along the entire circumference of the guide rail 280.

FIG. 6 shows an alternative development of a transport system according to the present invention. In the illustrated, non-limiting further development, an upper guide rail 380a and a lower guide rail 380b are provided, on which the large number of transport elements 370 are mounted by means of rollers 274. Here, too, the transport elements have holding devices 272 for holding and transporting the containers 110 and secondary parts 276 for magnetic interaction with the long stator 385. In this development, the long stator 385 is arranged on a central holder 386 in a rotationally fixed manner. However, it goes without saying that the development shown can be modified as described above in such a way that the long stator is designed to be rotatable.

The guide rails 380a and 380b are freely rotatably supported on the central column 386 via the ball bearings 381a and 381b indicated in FIG. 6, so that the movement of the transport elements 370, as described above, induces a rotation of the guide rails which in turn closes leads to less wear of the rollers 274 of the transport elements. Of course, this further development can also be modified accordingly in order to enable rotation of the guide rails driven by a motor.

In addition, the guide rails 380a and 380b of the further development shown each have a stabilizing device against radial lifting of the transport elements 370 when the long stator is switched off. These stabilizing devices are designed here as groove curves 390a and 390b along the top and bottom of the guide rails 380a and 380b, in which corresponding bolts 395a and 395b of the transport elements rotate. In normal operation, these bolts can rotate freely, ie without contact, within the groove curves. Only when there is no compensation of the radially acting forces due to the deactivated long stator or centrifugal forces, the (magnetic) holding forces in terms of amount exceed, the bolts 395a and 395b come into mechanical engagement with the flanks of the groove curves 390a and 390b and thus prevent the transport elements 370 from falling off the guide rails. It goes without saying that the illustrated further development of the stabilization device is only of an exemplary nature and that a large number of alternative further developments is conceivable.

The further developments of a linear motor-driven transport system shown in FIGS. 2 to 6 reduce the wear on the rollers and thereby enable longer service lives of the transport system and thus of the container treatment system. Since the rollers have to be replaced less frequently, the maintenance costs of the system can also be reduced. If the long stator is also designed to be rotatable, as described above, the heat development of the electrical coils of the long stator or the secondary part of the transport elements can also be reduced. This allows the transport system to be made more compact.

FIGS. 7a and 7b show schematic views of a container treatment system 15, which comprises a transport system 1 according to the developments described above. In addition, the container treatment system here comprises a plant part for blow molding containers 2 from preforms 2a, which in turn includes a preform feed 16, a heating section 17 for heating the preforms, an inlet star 18, a first container treatment machine 19, here a blow molding machine for example, and one Has outlet star 20.

The inlet star 18 is arranged in the inlet of the blow molding machine and takes over preforms from the heating section during operation and transfers them to the blow molding machine. The outlet star 20 is arranged in the outlet of the blow molding machine and takes over containers from the blow molding machine during operation and transfers them to the transport system, which according to the development shown can be viewed as a long-stator linear motor (LLM) graduation change star.

The container treatment system here further comprises an inlet star 21, a second container treatment machine 22, here a filling machine, and an outlet star 23, the inlet star 21 being arranged in the inlet of the filling machine and taking over containers from the LLM graduation change star during operation and transferring them to the filling machine and the outlet star takes over containers from the filling machine. As an alternative or in addition to the filling machine, a labeler or another machine for treating containers can also be provided, in particular in each case also with an associated inlet star and outlet star, which each transfer containers or take containers from them. It should be noted that the container treatment machines 19 and 22 can also be other machines and that the preform feed, the heating section and the various entry and exit stars are optionally provided. In particular, when using one of the transport systems described above for the graduation change star 1, the outlet star 20 and / or the inlet star 21 can be dispensed with. Instead, an LLM division change star in the sense of the transport systems described above can be interposed directly or with only one of the inlet and outlet stars 20 and 21 between the container handling machines 19 and 22. Optionally, further elements, in particular transport elements, can also be provided between the container treatment machines.

FIG. 7a shows the container treatment system with a half load, and FIG. 7b shows the container treatment system with a full load. For example, these loads can be used for containers of different sizes, for example for 1.5 I containers (half load) or 0.5 I containers (full load).

As can be seen, the distances between the preforms are larger in the preform feeder and in the heating section with half the load. In the blow molding machine, only every second blow station is occupied at half load. In the following filling machine, however, the same number of containers are shown with half and full loads, that is, the division into this machine is the same in each case. Gaps in the container flow that occur in the discharge from the blow molding machine when the load is half full are closed by the LLM graduation star.

For this purpose, depending on the load with which the system is operated, as described above, the motion profiles of the transport elements of the transport system 1 can be modified by means of the control unit of the linear motor in order to suitably adapt the spacing.

In an exemplary method for operating a container treatment system which comprises an LLM graduation change star according to the invention, in particular for operating the container treatment system described above, preforms are fed to a heating section by means of the preform supply, transported through the heating section and heated there, via the inlet star 18 fed to the blow molding machine and formed into a container at each blow molding station. The containers thus obtained are then taken over from the blow molding machine by means of the outlet star 20 and transferred to the transport system 1. This in turn transfers the containers (with changed division) to the infeed star of a subsequent machine, for example a labeling machine or a filler. The operation comprises at least a first operating mode in which each treatment station of the first container treatment machine is occupied (FIG. 7b) and a second operating mode in which not every, in particular only every second, treatment station of the first container treatment machine is occupied (FIG. 7a) ). The division in the second treatment system 22 is the same for the first operating mode and the second operating mode. The operating modes can be changed without any significant loss of time by simply adapting the movement profiles of the individually controllable transport elements. The high flexibility of the LLM graduation change star also allows individual gaps in the container flow, which can arise, for example, from rejecting defective containers, to be closed before being transferred to the second container treatment machine 22, so that seamless treatment along the subsequent process section is made possible.

Claims

Expectations

1 . Transport system for transporting piece goods, in particular containers (1 10), comprising: an essentially circular transport path with at least one long stator (285; 385) of a linear motor and at least one guide element (280; 380a-b); a plurality of individually controllable transport elements (270; 370) which are movably mounted on the at least one guide element (280; 380a-b); characterized in that the at least one guide element (280; 380a-b) and / or the at least one long stator (285; 385) are designed to be rotatable about an axis of rotation through the center point (264) of the transport path.

2. Transport system according to claim 1, further comprising at least one motor (282), in particular servo motor, which is designed to rotate the guide element (280) and / or the long stator (285) about the axis of rotation.

3. Transport system according to claim 2, further comprising a control and / or regulating unit (283), which is designed to control and / or regulate the at least one motor (282) such that a rotational speed of the guide element (280) and / o- of the long stator (285) is between a minimum speed and a maximum speed of the transport elements (270).

4. Transport system according to one of the preceding claims, wherein the guide element (280; 380a-b) and the long stator (285; 385) are designed to be rotatable, and wherein the guide element is designed to be non-rotatable with respect to the long stator.

5. Transport system according to one of the preceding claims, wherein the guide element (380a-b) is freely rotatable.

6. Transport system according to one of the preceding claims, wherein the number of transport elements (270; 370) mounted on the guide element (280; 380a-b) is greater than the quotient of 2p and the maximum desired angular division of the transport elements between a receiving point and one The point of delivery for the general cargo is along the conveyor.

7. Transport system according to one of the preceding claims, wherein the transport elements (270; 370) are mounted on rollers (274) on the guide element (280; 380a-b).

8. Transport system according to one of claims 2 to 7, wherein at least one motor (282) for driving the guide element (280) and / or the long stator (285) is designed as a torque motor, in particular as an external rotor.

9. Transport system according to claim 8, wherein the long stator (285) is designed as part of the torque motor, and in particular driving the rotation of the long stator is at least partially effected by magnetic interaction between magnets of the long stator and magnets of a stator of the torque motor.

10. Transport system according to one of the preceding claims, wherein the long stator (285; 385) is formed with a plurality of electrical windings in the form of solenoids which can be controlled individually or in blocks.

1 1. Transport system according to claim 10, wherein the linear motor is designed as an asynchronous linear motor.

12. Transport system according to one of the preceding claims, wherein the transport track, and in particular the at least one guide element (380a-b), has a stabilizing device (390a-b) against radial lifting of the transport elements (370) when the long stator is switched off .

13. Container treatment system with a transport system according to one of the preceding claims, a first container treatment machine (19) arranged upstream of the transport system (1), in particular a blow molding machine, and a second container treatment machine (22) arranged downstream of the transport system (1), in particular - One of a labeling machine and / or a filler, the linear motor being designed to adapt a movement profile of the transport elements (270) when the division in the outlet of the first container treatment machine is changed such that the division in the second container treatment machine (22) can be maintained is.

14. A method for transporting containers by means of a transport system (1, 100, 150, 155) according to one of the preceding claims, comprising the steps:

Picking up containers (110) by the transport elements (270) at a container inlet on the transport track; Dispensing the containers (110) from the transport elements (270) to a container outlet on the transport track; and

Transporting the containers (110) by individually controlled movement of the transport elements (270) by means of the linear motor from the container inlet to the container outlet; characterized in that the at least one guide element (280; 380a-b) and / or the at least one long stator (285; 385) during the transport of the containers (1 10) in the same direction as the movement of the transport elements (270) around the transport path rotate.

15. The method according to claim 14, further comprising the controlled driving of the rotation of the guide element (280) and / or the long stator (285) by means of at least one, in particular controllable, motor (282), in such a way that the guide element and / or rotate the long stator at a constant angular velocity.

16. The method according to claim 15, wherein the constant angular velocity of the guide element (280) and / or the long stator (285) lies in an interval which is determined by the angular velocity of the transport elements (270) when the container is received and the angular velocity of the transport elements (270) is limited when dispensing containers.

17. The method according to claim 16, wherein the constant angular velocity at which the guide element (280) rotates corresponds to the angular velocity of the transport elements (270) when the container is being dispensed.

18. A method for operating a container treatment system (15) according to claim 13, comprising the steps:

Treating the containers (2) in the first container treatment machine (19), in particular blow molding the containers,

Transfer the containers from the first container treatment machine (19) to the transport system (1), in particular via an outlet star (20) which is arranged between the first container treatment machine (19) and the transport system (1), and

Transferring the containers from the transport system (1) to the second container treatment machine (22), in particular via an inlet star (21) which is arranged between the transport system (1) and the second container treatment machine (22), wherein the operation of the container treatment system (15) comprises at least a first operating mode in which each treatment station of the first container treatment machine (19) is occupied and a second operating mode in which not every, in particular only every nth, treatment station of the first Container treatment machine (19) is occupied, where n is an integer greater than 1, in particular equal to 2, and the division in the second container treatment machine (22) is the same for the first operating mode and the second operating mode.