Abstract:
Disclosed is a rotary table machine for container treatment, comprising a carousel with container receptacles for conveying containers, wherein the container receptacles are arranged at a regular spacing along a circular path about an axis of rotation of the carousel by means of a machine pitch, characterized in that the carousel and a rotary transducer are connected via a transmission such that, when the carousel rotates about a machine pitch, the rotary transducer emits and/or processes a whole-number multiple of a periodic value increment as a position signal, a signal transmitter is designed to detect a reference mark on the carousel and for emitting a reference mark signal on the basis thereof, and a signal processing device is designed to process the position signal and the reference mark signal in order to regulate the position of the carousel and to control the container receptacles.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is the US national phase of International Patent Application No. PCT/EP2014/051364, filed Jan. 24, 2014, which application claims priority to German Application No. 102013205398.3, filed Mar. 27, 2013. The priority application, DE 02013205398.3, is hereby incorporated by reference. 
     FIELD OF THE DISCLOSURE 
     The invention relates to a rotary table machine for container treatment, and a method for a rotary table machine. 
     BACKGROUND 
     Rotary table machines for container treatment are usually designed as stretch-blow molding machine, rinser, filler, closer, inspection machine, labeling machine and/or printing machine for containers. The containers, for example bottles or cans, are received in a carousel in container receptacles and transported by them. To achieve high precision in the treatment, the position of the container receptacles must be determined with high precision during the rotation of the carousel. 
     The container receptacles are arranged at a regular spacing on the carousel along a circular path about the axis of rotation by means of a machine pitch. For example in a labeling machine, about 70 container receptacles are arranged at the carousel in which the containers are received and which are, in addition to the rotation of the carousel, pivoting about their own axis by means of a servomotor. Thereby, each container may be pivoted relative to a labeling unit such that the label may be applied to the complete container circumference. For a precise positioning of the label, the position of the carousel and thus that of the container receptacles relative to the labeling unit must be exactly known. 
     DE 69411 178 T2 discloses a carousel with container receptacles and a shaft, wherein a motor with a driving gearwheel engages a central gearwheel at the shaft. Moreover, the rotary transducer is additionally driven via the central gearwheel by which then the position of the carousel may be determined. 
     DE 10 2004 055 745 A1 also discloses a rotary table machine with a carousel and a shaft, the rotary transducer being here centrally arranged at the shaft. 
     In such rotary table machines it showed that the container treatment, such as for example the labeling, is insufficiently precise. 
     SUMMARY OF THE DISCLOSURE 
     It is the object of the invention to provide a rotary table machine that permits a more precise container treatment. 
     The invention solves this object in a rotary table machine for container treatment with the features of the characterizing part according to which the carousel and a rotary transducer are connected via a transmission such that, when the carousel rotates about a machine pitch, the rotary transducer emits and/or processes a whole-number multiple of a periodic value increment as a position signal, a signal transmitter is designed to detect a reference mark on the carousel and to emit a reference mark signal on the basis thereof, and a signal processing device is designed to process the position signal and the reference mark signal in order to regulate the position of the carousel and to control the container receptacles. 
     By the carousel and the rotary transducer being connected via a transmission such that, when the carousel rotates about a machine pitch, the rotary transducer emits and/or processes a whole-number multiple of a periodic value increment as a position signal, when the carousel rotates about the machine pitch, a sequence with a whole-number multiple of the periodic value increment is emitted as the position signal. For example, these may be 5000 periods of the value increment. When the carousel rotates further about the machine pitch, the same sequence of periodic value increments is emitted. In an arrangement of, for example, 60 container receptacles along the circular path, one machine pitch is exactly 6°. Within this machine pitch, the position of the container receptacles may then be resolved with 0.0012° at 5000 value increments per machine pitch. In other words, the transmission ratio permits a particularly high resolution of the position of the carousel. 
     By the signal transmitter being designed to detect a reference mark at the carousel and to emit a reference mark signal on the basis thereof, the reference mark or a corresponding reference container receptacle may be determined as the zero position of the carousel. As a consequence, due to the regular distance of the container receptacles, it may be determined at which position each individual container receptacle is located at the carousel. Thereby, for example each individual container receptacle may be exactly correlated with a treatment station, and the pivot of the container receptacles may be activated corresponding to their positions. 
     By the signal processing device being designed to process the position signal and the reference mark signal in order to regulate the position of the carousel and to control the container receptacles, both the position of the carousel and the movement of the container receptacles are regulated or controlled based on these signals. Thereby, variations between the carousel&#39;s rotation and the determination of the position of the container receptacles are avoided. Correspondingly, a high precision of container treatment is achieved. 
     The rotary table machine for container treatment may be arranged in a beverage processing plant. The rotary table machine may be a stretch-blow, cleaning, labeling, inspection, filling or closing machine for containers. The containers may be bottles, cans, cups or the like. The container receptacles may be designed to rotate about their own axis. A control cam or servomotors may be designed to rotate the container receptacles about their own axes. The container receptacles may comprise clamping elements to stably receive the containers therein. 
     The machine pitch may be 360° divided by the number of container receptacles at the carousel. For example, the machine pitch is 6° in case of 60 container receptacles along the circular path. 
     The axis of rotation of the carousel may extend perpendicularly through the center of the carousel. The carousel may include a shaft along the axis of rotation. The axis of rotation of the carousel may extend vertically. The shaft of the carousel may be mounted in frame elements by a bearing. The carousel may be connected to a motor to drive it. 
     The rotary transducer may be an optical, inductive or magnetic rotary transducer. The inductive rotary transducer may be designed as tachogenerator or resolver. The rotary transducer may emit, per revolution, a whole-number multiple of the periodic value increments as a pulse train as a position signal. The position signal may be a periodic square wave signal or sinusoidal signal. As an alternative, the rotary transducer may be designed to process the position signal and emit it as a position value. The emission of the position value may be accomplished via a data bus. The rotary transducer may be an absolute value rotary transducer (SSI rotary transducer) or an incremental rotary transducer. 
     The reference mark may be arranged at an outer periphery of the carousel. The reference mark may comprise a magnet or an optical mark. The signal transmitter may comprise a magnetic switch or a photocell for detecting the reference mark. 
     The signal processing device may comprise a micro processor, digital inputs and/or outputs, analogue inputs and/or outputs which are optionally designed to read the position signal and/or the reference mark signal. 
     The signal processing device may be connected with the motor for driving the carousel and/or with servomotors for pivoting the container receptacles. The signal processing device may comprise a regulation loop to regulate the position of the carousel based on the position signal. The signal processing device may be designed to control the container receptacles depending on the position signal. The signal processing device may be designed to regulate the servomotors of the container receptacles with a regulation loop on the basis of pivoting angles of the container receptacles. The container receptacles or the servomotors may comprise rotary transducers to detect the pivoting angles. 
     The signal processing device may be designed to process the position signal in order to control a unit for container treatment. Thereby, with the position signal and the reference mark signal, the unit may be additionally controlled and the precision of the container treatment increased. The unit may be a filling station, a labeling unit, an inspection unit and/or a closing head. For example, in a labeling unit, labeling may be particularly well synchronized with the rotation of the carousel based on the position signal and the reference mark signal as for all drives the same time base applies. The signal processing device and the unit may be connected with a control line. 
     A zero point of the position signal may be freely selectable. Thereby, in a commissioning or maintenance process, a defined position of the carousel may be stored in the rotary table machine. The zero point may be stored in the rotary transducer or in the signal processing device. Edges of the position signal may be selected as zero point. 
     The transmission may comprise a reduction ratio such that, when the carousel rotates about a machine pitch, a shaft of the rotary transducer rotates by one, two or four revolutions, or by half a revolution or a quarter revolution. Thereby, it may be particularly easily ensured that in a rotation of the carousel about a machine pitch, the position signal passes over a whole-number multiple of the periodic value increment. 
     The transmission may comprise a sprocket belt with rounded teeth. Thereby, a particularly quiet running of the rotary transducer is achieved since the rounded teeth can engage a gearwheel particularly smoothly. The transmission may comprise at least two gearwheels which are connected via the sprocket belt, the gearwheels having the same or different diameters. The gearwheels may have teeth corresponding to the sprocket belt. The sprocket belt may have tooth profiles which are arranged diagonally with respect to the running direction of the sprocket belt. Thereby, the teeth may engage the gearwheels even more easily. The sprocket belt may consist of a plastic material. The tension of the sprocket belt may be applied with a tension roller. 
     The transmission may comprise a motor control gear which is coupled to a motor at a driving end for introducing a driving force, and which is arranged at a driven end between the rotary transducer and the carousel. Thereby, the forces and torques between the motor control gear and the carousel may be particularly well decoupled from the rotary transducer. This ensures a particularly quiet running of the rotary transducer. The motor control gear may comprise two driven ends, the first driven end being connected to the carousel via at least two gearwheels and the second driven end being coupled to the rotary transducer via at least two other gearwheels. The two driven ends may be the two ends of one shaft. 
     The sprocket belt may be arranged between the motor control gear and the rotary transducer. Thereby, the sprocket belt is particularly well decoupled from the driving forces and the rotary transducer may operate particularly precisely. The sprocket belt may engage a gearwheel at the driven end of the motor control gear and a further gearwheel at the rotary transducer. 
      The rotary transducer may be designed to emit and/or process a coarse signal whose period corresponds to a whole-number multiple of the periodic value increments. Thereby, interferences in the position signal may be particularly well detected. 
     A period of the coarse signal may correspond to one machine pitch. Thereby, only on the basis of the position signal and the coarse signal, an absolute position value may be determined within the machine pitch. The rising or falling signal edges of the coarse signal may correspond to reference positions of the container receptacles. 
     A zero point of the coarse signal may be freely selectable. Thereby, the coarse signal may be particularly easily calibrated relative to the actual positions of the container receptacles in the rotary table machine. The zero point of the coarse signal may be stored in the rotary transducer or in the signal processing device. 
     The signal processing device may be designed to define a time slot around the reference mark detected by the signal transmitter and identify a signal edge of the coarse signal within the time slot as a zero position of the carousel. Thereby, the absolute position of the carousel may be particularly precisely detected since the signal edge of the coarse signal serves as the zero position which is more precise than the reference mark detected by the signal transmitter. For the zero position, the carousel may be rotatable to a predetermined reference position. Thereby, the carousel may be particularly easily calibrated in the rotary table machine during installation and/or service works. 
     A safety rotary transducer may be designed to detect a safe speed of the carousel, the safety rotary transducer being optionally integrated with the rotary transducer. Safety rotary transducer can mean that the rotary transducer is a SIL rotary transducer according to the EN 61508 standard. Thereby, the speed of the carousel may be monitored independent of the correct function of the rotary transducer, and in case of a deviation from an expected speed, the rotary table machine may be stopped and/or an alarm may be triggered. Thereby, the rotary table machine may be particularly well protected. The fact that the safety rotary transducer is integrated with the rotary transducer can mean that the safety rotary transducer is embodied as an additional independent evaluation unit of the rotary transducer. As an alternative, this can mean that the safety rotary transducer and the rotary transducer are connected by a common shaft. The rotary transducer may comprise an electrical connection for emitting the position signal and/or the coarse signal, and the safety rotary transducer may comprise a separate electrical connection for emitting a speed signal. 
     Moreover, the invention provides a method for a rotary table machine for container treatment, wherein containers are transported in container receptacles which are arranged at a regular spacing along a circular path about an axis of rotation of the carousel by means of a machine pitch, and a rotary transducer emits and/or processes a position signal with periodic value increments for determining the position of the carousel, characterized in that a transmission transmits the machine pitch of the carousel to a whole-number multiple of the periodic value increments of the rotary transducer, a signal transmitter detects a reference mark at the carousel and emits a reference mark on the basis thereof, and a signal processing device processes the position signal and the reference mark signal in order to regulate the position of the carousel and to control the container receptacles. 
     By both the position of the carousel and the container receptacles being regulated or controlled on the basis of the position signal and the reference mark signal, the rotation of the carousel and the movement of the container receptacles are synchronized based on the position signal and the reference mark signal. Moreover, by the transmission ratio, a particularly high resolution of the machine pitch is ensured by the periodic value increments of the rotary transducer. Thereby, the position signal is a signal with particularly high resolution. Moreover, with the aid of the reference mark at the carousel, the signal transmitter may detect an absolute position of the carousel, and the absolute position of each container receptacle may be determined. Correspondingly, the movement of each container receptacle may be controlled depending on its current position along the circular path. 
     The above described embodiments or parts thereof, may be combined with the following embodiments. 
     The rotary transducer may emit a coarse signal whose signal edges correspond to reference positions of the container receptacles. Thereby, the position of the container receptacles may be particularly precisely determined at the reference positions. 
     Within a time slot around the reference mark detected by the signal transmitter, a signal edge of the coarse signal may be identified as zero position of the carousel. Thereby, a particularly precise zero position of the carousel may be determined. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Features and advantages of the invention will be illustrated below with reference to the embodiments represented in the figures. In the figures: 
         FIG. 1  shows a lateral representation of a rotary table machine; 
         FIG. 2  shows a schematic plan view of the rotary table machine of  FIG. 1 ; 
         FIG. 3  shows a schematic signal representation of the position signal, the reference mark signal, and the coarse signal within a machine pitch; and 
         FIG. 4  shows a sectional view of a sprocket belt for the rotary table machine of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a rotary table machine  1  in a lateral representation. One can see a carousel  2  that is designed with rotary tables and at the circumference of which the container receptacles  14  are arranged. The container receptacles are moved by the servomotors  15 . The carousel  2  comprises a shaft  19  which is rotatably mounted at both ends with the bearings  16  at the upper and lower frame elements  17  and  18 , respectively. With each container receptacle  14 , one container  3  each may be stably received and pivoted by the servomotors  15 . The containers  3  are secured against shifting at the upper end via the fixing elements  20 . The fixing elements  20  are movably mounted in the head plate  21  and connected to the shaft  19 . When the carousel  2  is rotating, each fixing element  20  corresponds to the corresponding container receptacle  14 . 
     The motor  13  is provided as the drive of the carousel  2 . Here, the motor control gear  10   b  reduces the speed of the motor  13  to a lower speed on the driven end of the motor control gear  10   b . The driven end of the motor control gear  10   b  is connected to the shaft  19  of the carousel  2  via the first partial transmission  10   a . The first partial transmission  10   a  further reduces the speed of the driven end of the motor control gear  10   b . The first partial transmission  10   a  comprises a first gearwheel at the driven end of the motor control gear  10   b , a gearwheel which is larger compared to this at the shaft  19  of the carousel  2 , and a sprocket belt which connects both gearwheels. As an alternative, the two gearwheels may also engage directly. 
     One can moreover see that the containers  3  are provided with labels  3   a  by the labeling unit  23 . For a high precision in labeling, a precise positioning of the containers  3  relative to the labeling unit  23  is required. This will be described below: 
     For a precise determination of the position, the carousel  2  and the rotary transducer  4  are connected by the transmission  10 . The transmission  10  comprises the above described first partial transmission  10   a , the motor control gear  10   b  and the second partial transmission  10   c  connected at the second driven end. The second partial transmission  10   c  comprises a first gearwheel which is connected to the second driven end of the motor control gear  10   b , a second gearwheel which is connected to the shaft  4   a  of the rotary transducer  4 , and a sprocket belt  10   d  which connects both of them. The second partial transmission  10   c  may be embodied with or without transmission ratio. The first partial transmission  10   a , the motor control gear  10   b , and the second partial transmission  10   c  together have one transmission ratio, so that one machine pitch of the carousel  2  corresponds to a complete rotation of the shaft  4   a  at the rotary transducer  4 . The rotary transducer  4  is here embodied as optical rotary transducer which emits, per revolution of the shaft  4   a , exactly 5000 periods of a periodic value increment as position signal. Consequently, one rotation of the carousel  2  about one machine pitch exactly corresponds to 5000 periodic value increments of the rotary transducer  4 . Thereby, a particularly high resolution of the movement of the carousel  2  is possible. The rotary transducer  4  emits the position signal to the signal processing device  11  at the electric line  12   a  as a square wave signal. As an alternative, it may also be a sinusoidal signal. 
     Moreover, the rotary transducer  4  is designed to emit a coarse signal, wherein one period of the coarse signal corresponds to a complete revolution of the axis of rotation  4   a  of the rotary transducer. The coarse signal is also a square wave signal which is here emitted at the electric line  12   b . One first half period exactly corresponds to one half revolution of the rotary transducer  4  or 2500 value increments, respectively. The second half period of the coarse signal corresponds to the second half rotation of the rotary transducer  4  or to further 2500 value increments of the position signal, respectively. 
     The line  12   c  is moreover shown for the power supply of the rotary transducer  4 . 
     A safety rotary transducer  4  is shown to be integrated with the rotary transducer  4 . It detects a safe speed of the carousel  2  and emits it at a separate line  12   d . By this, the rotation of the carousel  2  may be monitored. This is done here by the monitoring device  11 , which compares the safe speed with an expected speed. In case of a difference, the rotary table machine  1  will be stopped and an alarm will be triggered. 
     Moreover, the signal transmitter  9   b  is shown which detects the reference mark  9   a  at the carousel  2 . The reference mark  9   a  is here embodied as a magnet which is detected with a magnetic switch in the signal transmitter  9   b . As soon as the reference mark  9   a  is opposite the signal transmitter  9   b , the latter emits a voltage pulse as signal via the line  12   g.    
     The above described signals are detected by the signal processing device  11 . The latter is embodied with a micro processor and digital inputs for detecting the signals at lines  12   a ,  12   b , and  12   g . In the process, the signals are processed with the signal processing device  11 , as will be described below with reference to  FIG. 3 , in order to calculate an absolute position of the carousel  2  with high resolution. With this absolute position of the carousel  2 , the motor  13  for driving the carousel  2 , the servomotors  15  for moving the container receptacles  14 , and the labeling unit  23  are then regulated or controlled, respectively. Since these three units are controlled or regulated on the basis of a common time base, i. e. the absolute position of the carousel  2 , a particularly precise labeling of the containers  3  with the labels  3   a  is possible. 
     The activation of the motor  13  is done via the lines  12   e  with a pulse-width control. The labeling unit  23  comprises a separate control device which is exactly triggered in terms of time via the line  12   h . Moreover, the servomotors  15  are connected to the signal processing device  11  via the rotary distributor  22  and the line  12   f . Here, the signal processing device  11  comprises a regulation loop for each servomotor  15  which in turn comprise separate rotary transducers (not represented here) for the exact regulation of the pivot of the container receptacles  14 . 
     In  FIG. 2 , one can see the rotary table machine  1  of  FIG. 1  in a plan view. One can see here the carousel  2  which comprises six container receptacles  14   a - 14   f . These are arranged at regular distances along the circular path K, and consequently, one machine pitch M exactly corresponds to 60°. One can also see the zero position R of the carousel  2 , where here the reference mark  9   a  is exactly opposite the signal transmitter  9   b . For this zero position R, the container receptacles  14   a - 14   f  are at the positions 0°, 60°, 120°, 180°, 240° and 360. The rotational positions of each container receptacle  14   a - 14   f  with respect to the position of the carousel  2  may be stored as curves in the signal processing device  11 , where with each curve, the rotational position of a certain container receptacle  14   a - 14   f  is correlated with the position of the carousel  2 . 
     One can moreover see that the shaft  19  of the carousel  2  is connected to the rotary transducer  4  via the transmission  10  (only schematically shown here). 
       FIG. 3  shows, in a schematic representation, the position signal  5 , the reference mark signal  7 , and the coarse signal  6  as time characteristic over time t within a machine pitch M. 
     One can see that the coarse signal  6  is a square wave signal which exactly passes through one period within one machine pitch M as of the reference point in time T R . Moreover, the reference point in time T R  corresponds to the zero position R of the carousel  2  shown in  FIG. 2 . The zero point of the coarse signal  6  is the positive signal edge  6   a  and is selected such that it corresponds to the zero position of the carousel  2  (see  FIG. 2 ). 
     The position signal  5  is here also a square wave signal, but it can alternatively also be a sinusoidal signal. Here, the position signal  5  passes exactly through 5000 periods during one machine pitch M. These may also be, corresponding to the design of the rotary table machine, 2000, 1000, 500, 100 or 10 periods. The number of periods of the position signal  5  is here only shown schematically to better show the correlation of the individual signals. One can see that the position signal  5  comprises the periodic value increments  5   b  which exactly pass through one period during the period At. One can also see that the zero point of the position signal  5  is the signal edge  5   a  and selected such that it corresponds to the zero position R of the carousel  2  (see  FIG. 2 ). Correspondingly, the positive signal edge  5   a  of the position signal  5  is exactly at the reference point in time T R . One can also see that one period of the coarse signal  6  corresponds to one whole-number multiple of the periodic value increments  5   b  of the position signal  5 . 
     Moreover, the reference mark signal  7  is shown which is emitted by the signal transmitter  9   b  when at the zero position R, the reference mark  9   a  is opposite the signal transmitter  9   b . Here, the signal transmitter  9   b  is particularly simply designed with a magnetic switch, wherein by production tolerances, the signal pulse  7   a  of the reference mark signal  7  comes within the slot F. If now the reference mark signal  7  would be taken directly for an absolute position signal of the carousel  2 , the actual position of the carousel  2  within the slot f would be known relatively inexactly. Correspondingly, the rising signal edge  6   a  of the coarse signal  6  is identified as zero position R of the carousel  2  within the slot F with the signal processing device. Subsequently, the absolute position signal for the carousel  2  is formed of the coarse signal  6  and the position signal  5 , for example by integration of the value increments  5   b  as of the reference point in time T R . Hereby, on the one hand the passage of the container receptacle  14   a  is detected, and simultaneously a particularly exact absolute position of the carousel  2  is determined. 
     By the particularly exact position signal  5  detected with high-resolution, and by the absolute position of the carousel  2  determined in connection with the coarse signal  6  and the reference mark signal  7 , the rotation of the carousel  2 , the pivot of the container receptacles  14 , and the labeling unit  23  may be regulated or controlled particularly exactly and with a particularly high resolution since it is done based on a common time base. 
     In  FIG. 4 , the sprocket belt  10   d  of the rotary table machine  1  of  FIGS. 1 and 2  is shown in a sectional view. One can see that the sprocket belt  10   d  has rounded teeth  10   e.    
     Each tooth  10   e  has rounded radii R 1 , R 2  by which the sprocket belt  10   d  more easily engages the corresponding gearwheels of the partial transmission  10   c  (not represented here). The radii R 1 , R 2  are smaller than half the width B of each tooth. Optionally, the radii R 1 , R 2 , are smaller than one quarter of the width of the tooth  10   e . Moreover, one can see that the lateral edges  10   f  of the teeth  10   e  include an inclination  10   f  which is inclined with the angle S with respect to the running direction (indicated by the arrow). The angle S is here within a range of 60 degrees to 90 degrees, optionally within a range of 70 degrees-80 degrees. Thereby, the teeth  10   e  may engage the corresponding gearwheels of the partial transmission  10   c  even more easily. 
     With the rotary table machine  1  shown in  FIGS. 1-4 , the methods corresponding to claims  13 - 15  may be carried out. 
     It will be understood that features mentioned in the above described embodiments are not restricted to these special combinations and are also possible in any other combinations.