Abstract:
A container capping control device for a machine may include at least one capping head adapted to place a closure member on a container. The capping head may include a driving motor. The device may include a calculation unit, a graphical man-machine interface and a plurality of capping programs adapted to be parameterized by means of the interface. A capping program may be adapted to control the capping head in accordance with at least one phase of rotation of the closure member when the capping program is executed by the calculation unit.

Description:
BACKGROUND  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to the field of control of electric motors. More particularly, the present invention relates to the control of electric motors in container capping machines. The present invention may be applied in fields in which an electric motor must apply torque to an object in a precise manner, for example in the field of screwing threaded closure caps, and in the field of applying snap-fastening closure caps.  
         [0003]     2. Description of Related Art  
         [0004]     Document EP 0 524 196 discloses a screwing device comprising a capping cone, a motor for driving rotation of the capping cone, a switching device, and a power supply. A control system comprises a torque sensor adapted to measure an instantaneous drive torque, a comparator for comparing the instantaneous torque with a closure torque of predetermined value, and a sensor for the angle of rotation of the cap receiving member adapted to be activated only when the instantaneous torque reaches the predetermined value. Thus, a drive torque is applied to a cap to screw it onto a container, the instantaneous torque applied to the cap is measured and compared with a closure torque of predetermined value, and the angle of rotation of the cap is measured only when the instantaneous torque reaches the predetermined value. The presence of a torque sensor and an angular sensor, however, leads to some complication of the device without guaranteeing highly reliable and convenient closure of containers by the caps.  
         [0005]     Document FR A 2 807 265 describes an electric motor control device equipped with at least one means of measuring the current consumed by the motor, a means for measuring the torque supplied by the motor, a power supply means for the motor, and an initialization unit. The initialization unit is capable of generating a torque set point and of receiving and processing information relating to the current and to the torque to deduce therefrom a relationship between the torque set point, the torque and the current in order thereafter to be able to determine the torque applied from the set point and from the current, which significantly simplifies calibration operations.  
         [0006]     A bottling line including one or more container capping machines was conventionally dedicated to one particular type of container and to one particular type of cap and therefore programmed once and for all when first put into service. Changing caps and/or containers or a method of placing the cap on the container easily and with the shortest possible interruption of operation of the machine would be advantageous. Conventionally, such changes require a visit by qualified data processing specialists to reprogram the machine and a relatively long stoppage. For machines having a throughput that may exceed 50,000 containers per hour, the cost of stopping production is very high.  
       SUMMARY  
       [0007]     In some embodiments, a container capping control device is intended for a machine including at least one capping head adapted to place a closure member on a container. The capping head includes a motor for driving the closure member. The container capping control device may include a calculation unit, a graphical man-machine interface and a plurality of capping programs adapted to be parameterized by the interface. A capping program is adapted to control the capping head in accordance with at least one phase of rotation of the closure member when the program is executed by the calculation unit.  
         [0008]     An operator is able to choose the program best suited to the container and to the closure member from a plurality of capping programs. The operator may choose to fix the values of capping parameters from parameters proposed on the graphical interface as a function of the container and the closure member. The graphical interface advantageously includes a plurality of windows with at least one window per capping program.  
         [0009]     In one embodiment, a capping program step is defined by a starting angle, a stopping angle, a limit torque, a limit torque tolerance and a maintaining duration. The starting angle of one step is by default equal to the stopping angle of the preceding step. A window of the graphical interface may be provided for each capping program step that an operator is able to define in this way.  
         [0010]     In one embodiment, a capping program step is defined by a torque regulation factor, a turret ratio and a path angle.  
         [0011]     In one embodiment, the container capping control device includes a capping program with a high starting torque. Thus, good interengagement of the threads of the container and of the closure member may be guaranteed.  
         [0012]     In one embodiment, the container capping control device includes a capping program including orientation of the closure member for snap-fastening. This capping program may be well adapted to non-circular closure members. This capping program including orientation of the closure member for snap-fastening may also be used with circular closure members.  
         [0013]     In one embodiment, the container capping control device includes a capping program with screwing checked by application of a low unscrewing torque. The low unscrewing torque may be applied at the end of a screwing step. Failure of the unscrewing torque to cause rotation is characteristic of correct capping.  
         [0014]     In one embodiment, the container capping control device includes a capping program commanding rotation of the capping head before contact between the closure member and the container.  
         [0015]     In one embodiment, the container capping control device includes a capping program starting on a rising edge, a falling edge or a change of state of an external electrical signal.  
         [0016]     In one embodiment, the container capping control device comprises a cell for detecting the angular orientation of the closure member and a capping program including angular indexing of the closure member by the detection cell.  
         [0017]     In some embodiments, a container capping machine includes at least one capping head adapted to place a closure member on a container and including a motor for driving the closure member. The machine may be further equipped with a container capping control device comprising a calculation unit, a graphical man-machine interface, and a plurality of capping programs adapted to be parameterized by means of the interface. A capping program may be adapted to control the capping head according to at least one phase of rotation of the closure member when the program is executed by the calculation unit.  
         [0018]     In certain embodiments, a method of controlling capping of containers may include using a machine with at least one capping head adapted to place a closure member on a container. The capping head may include a motor for driving the cap and the machine may include a calculation unit. An operator may parameterize at least one capping program via a graphical man-machine interface. A capping program may be adapted to control the capping head in accordance with at least one phase of rotation of the closure member when the capping program is executed by the calculation unit. An operator may start the execution of a capping program from among a plurality of capping programs. Thus, the operator may easily make a choice between the various capping programs. If the capping programs are already parameterized appropriately, the chosen capping program may be executed directly. On the other hand, if the capping program chosen necessitates further parameterization, then the operator may effect the parameterization before starting the execution of the capping program. In one embodiment, the operator parameterizes a single capping program and then starts the execution of the parameterized capping program.  
         [0019]     Advantages of the capping machine and the container capping control device include, but are not limited to, having a multipurpose device that is easy to use, simple, flexible and has operating parameters that may be modified in a simple manner on the basis of limited basic knowledge. A universal capping machine may be easy to parameterize and may be able to handle varied containers, closure members and capping modes, within limits imposed naturally by mechanical and electrical components of the capping machine. For example, the same capping machine could process 0.5 liter, 1 liter or 1.5 liter synthetic water bottles with a basic cap or a nozzle cap with no particular difficulty. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     Advantages of the present invention will become apparent to those skilled in the art with the benefit of the following detailed description and upon reference to the accompanying drawings in which:  
         [0021]      FIG. 1  is a diagrammatic view of an embodiment of a bottling machine motor.  
         [0022]      FIG. 2  is a block diagram of an embodiment of a motor control circuit.  
         [0023]      FIGS. 3-6  depict embodiments of graphical interface windows.  
         [0024]     While the invention may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. The drawings may not be to scale. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.  
     
    
     DETAILED DESCRIPTION  
       [0025]     A machine for applying caps onto bottles may be installed in a bottle processing line. The bottles generally follow a circular arc trajectory in the machine. The bottles receive a cap that is screwed on or snap-fastened. The bottles afterwards exit the machine. The caps are taken up one by one by holding members which move toward the neck of a bottle, for example by virtue of a vertical downward movement. Each cap is each attached to a bottle by rotation or by snap-fastening. The caps are applied to the bottles when the bottles are following along the circular arc trajectory in the machine.  
         [0026]     Diagrammatically, the cap screwing machine includes a plurality of motors  1  each associated with a controller  4  adapted to provide the motor with an appropriate electrical power supply. The holding members that are normally fitted to the output shaft of the motors are not shown. The motors  1  and the controllers  4  form part of a rotary assembly, usually called a turret  5 . The turret may be adapted to turn in the direction of the arrow  6 , for example. A turret  5  may support several tens of motors  1 .  
         [0027]     The turret  5  is equipped with a rotary collector  7  for the passage of signals between the controllers  4  and non-rotary parts of the machine. A toothed wheel  8  is also provided, fastened to the turret  5  and meshing with another toothed wheel  9  carried by a shaft provided with an angular position sensor  10  that emits an electrical output signal representative of the angular position of the toothed wheel  9  and consequently of the toothed wheel  8  and the turret  5 . The sensor  10  is mounted on a non-rotary part of the machine.  
         [0028]     The machine may include a power supply  11  connected to the rotary collector  7  and adapted to supply the controller  4  with the electrical power necessary for driving the motors  1 . A control power supply  12  may also be connected to the rotary collector  7 . The control power supply  12  may be adapted to provide the controller  4  with a low-power power supply in the form of a DC voltage of 12 or 24 volts. The power supplied to the controller may be of the type intended for control of electronic circuit cards  4 . Control power supply  13  may provide power for non-rotary parts of the machine.  
         [0029]     The machine may include a display screen  14 , an automaton  15 , a central unit  16 , a communication bus  17 , for example of the RS232 type, and a high bit rate communication bus  18 , for example of the Can Open type.  
         [0030]     The control power supply  13  may be connected to the user interface  14 , the automaton  15  and the central unit  16 . The automaton  15  is adapted to communicate with the other parts of the machine via the bus  17 . The position sensor  10  is connected to the high bit rate bus  18 . The rotary collector  7  is connected to the high bit rate bus  18  so that information coming from or addressed to the controllers  4  may be exchanged rapidly. The central unit  16  is connected to the bus  17  and to the bus  18 . The automaton  15  drives the functions and controls of the machine and supplies capping set points to the central unit  16 .  
         [0031]     The controllers  4  may take the form of control and power modules conforming to set points received from the central unit  16  via the high bit rate bus  18  for starting and stopping the motors, regulating the speed, limiting the torque, monitoring the rotational displacements of the motors, for example in increments of 10°, measuring the current consumed, storing samples thereof, and providing reports on the action effected and its status.  
         [0032]     The motors  1  may, for example, comprise a stator with three windings distributed over a large number of notches. Each motor  1  may be provided with three Hall effect sensors  2  and a rotor comprising twelve permanent magnets, and be encapsulated in a sealed casing. The rotor is mounted on a shaft supported by a bearing with a double row of balls, terminating in a drive system  3  of the type with six flats for fast coupling to cap holding systems.  
         [0033]      FIG. 2  shows details of the architecture of an embodiment of a motor controller. The controller  4  of a motor  1  includes a processing unit  19 ; a current regulator  20 ; a current sensor  21  for measuring a current in the current regulator  20  and sending an output signal to the processing unit  19 ; a speed processing unit  22  receiving the output signal of the Hall effect sensors  2  and, following signal processing and shaping, sending a signal representative of the speed of the motor  1  to the processing unit  19 . The processing unit  19  is also connected to the buses  17  and  18 , to a network address selector  23 , to a programming unit  24 , and to a control display unit  25  of the type including green light-emitting diodes that are lit in the event of satisfactory status, one of which may be representative of a supply voltage, another of the connection to the bus  17 , another of the connection to the bus  18 , etc.  
         [0034]     A computer  26 , for example a PC, may be connected to the bus  18 . The computer  26  comprises a casing  27  equipped with random access memory, read only memory, an internal bus, a processor and software stored in the memories. In particular, graphical interface software is provided for displaying interactive windows on a screen  28  with the aid of a mouse  30  and a keyboard  29  available to an operator. Parameterizing software interacting with the graphical interface software, which is also executed by the processor, is also provided.  
         [0035]     Structural data for each motor  1  of the turret  5  is stored in the central unit  16 , in particular the torque constant of the motor  1  expressed in Nm/A, the number of poles of the motor  1 , the screwing head number, the resolution of the sensor  10  and, where applicable, other constant parameters defining the machine, such as the rotation direction and the number of heads.  
         [0036]     Parameters of the cycles and parameters of the phases of each cycle are defined in the computer  26 . A screwing cycle or screwing program is defined by the list of phases, start and end of cycle angles and a torque control tolerance expressed as a percentage.  
         [0037]     A phase of a cycle is parameterized by a triggering threshold for maintaining the torque expressed as a percentage of the set point torque, a torque maintaining time, a definition of starting the motor  1 , for example on an external signal or at the end of the preceding phase, the rotation speed of the motor  1 , which is a positive or negative value regulated as a function of the throughput of the capping machine, a maximum current, a path, which may be limited or unlimited, and a stopping definition, for example on an external signal, on reaching the maximum current, on a path traveled or on a maximum elapsed time for the phase.  
         [0038]     The computer  26  connected to the central unit  16  by the bus  18  stores and transfers the characteristics of the capping cycles to be executed. The parameterization data is then transmitted and stored in the memories of the central unit  16  and via the bus  17  to those of the controllers  4  as a function of where the processing is performed (centrally or remotely).  
         [heading-0039]     The following capping cycles in particular may be provided: 
         [none]    
       
          Basic screwing, characterized by the action of starting the motor before contact of the cap with the bottle to be capped, at a particular speed and maximum torque, until that torque is reached.  
          Screwing with a high starting torque, used when the inrush current on starting the motor may exceed the limit programmed for the torque or in the event of screwing beginning after the application of a vertical pressure to the cap. This cycle breaks down into a starting phase and a screwing phase analogous to basic screwing.  
          Indexing, characterized by the prior orientation to within ±180° of a cap to be snap-fastened. The indexing cycle is generally followed by repositioning after snap-fastening the cap.  
          Repositioning with monitoring of the position of the head relative to magnets of the head. Repositioning is reflected in the impossibility of quitting the position defined by the magnets or of effecting the path as far as the next resting position.  
          Orientation by external cell, which consists in turning the cap out of contact with the container until a colored or raised mark is detected by a detector cell and, where necessary, effecting an additional path to position the cap before snap-fastening. The cell is connected directly to the controller  4  of the motor  1 .  
          Screwing and checking by unscrewing, comprising first of all basic screwing or screwing with a high starting torque, followed by unscrewing at a low torque and monitoring displacements by means of the Hall effect sensors  2  to confirm the quality of screwing.  
          Square cap screwing, in which, to ensure that the faces of the cap line up with those of the bottle, the cap is taken up from the dispensing star of the capping machine in the final screwing position by a head with a shaped end-piece. Tightening is effected by quarter-turns until a minimum torque is reached guaranteeing that the container is sealed.
 
 The parameters defining the phases are as follows:
 
          The starting angle is a value expressed in increments of the sensor  10  from a reference zero for starting the motor  1 . The number of points corresponding to the pitch of the screwing heads is added to calculate the starting angle of the next screwing head.  
          The turret ratio is a multiplier coefficient for the rotation speed of the turret  5  for obtaining in real time that of the screwing head. The rate of progress through the steps of the sensor  10  is used to calculate the instantaneous speed.  
          The limit torque is the value of the torque required at the end of screwing or at the end of an action controlled by the torque. The torque generally being proportional to the current supplied by the controller  4 , the torque value may be converted to a maximum current to be supplied to the motor  1  by the controller  4 .  
          The torque regulation factor is a coefficient inversely proportional to the speed of the turret  5  and applied to the limit torque to compensate the inertia of the screwing heads.  
          The limit torque tolerance is a tolerance region of the limit torque in which the sampled values are valid for totalizing the torque maintaining time. At the end of a cycle, a measurement lying outside the tolerance region triggers an error message.  
          The maintaining time is the time for which the limit torque is applied before the motor  1  is stopped automatically.  
          The stopping angle is a value expressed in steps of the sensor  10  and starting from a reference zero for cutting off the power supply of the motor of the first head of the machine if it has not already been stopped by the limit torque. The number of steps corresponding to the screwing head interval is added to calculate the stopping angle of the next screwing head.  
          The path is the rotation to be accomplished during which the initial parameters of the phase of the cycle are applied before effecting another phase, a test, or stopping the motor.  
          The fixed speed is independent of the rotation speed of the turret  5  as a function of the inertia of the head at the maximum throughput. The fixed speed may replace the turret ratio.  
          The stopping signal contains the identification of the origin of the signal for the change of cycle after detection by a cell.  
          The path test compares the path really effected with the programmed value.  
          The torque test compares the measured torque with the programmed torque value. 
       
     
         [0060]     The table below illustrates the definition of different types of screwing cycles.  
                                       Group   Phases   Parameters                   Basic screwing   1/1-Screwing   Starting angle (coder step)               Turret ratio (turns/turns)               Limit torque (N · m)               Torque regulation factor               Limit torque tolerance (%)               Maintaining time (ms)               Stopping authorization               Stopping angle (coder step)       Screwing with   1/2-High starting torque   Starting angle (coder step)       high starting   2/2-Screwing   Turret ratio (turns/turns)       torque       Limit torque (N · m)               Path (turns)               Stopping authorization               Limit torque (N · m)               Torque regulation factor               Limit torque tolerance (%)               Maintaining time (ms)               Stopping authorization               Stopping angle (coder step)       Indexing   1/2-High starting torque   Starting angle (coder step)           2/2-Rotation/stopping on   Fixed speed (rpm)           magnets   Limit torque (N · m)               Path (turns)               Stopping authorization               Limit torque (N · m)               Limit torque tolerance (%)               Maintaining time (ms)               Stopping authorization               Stopping angle (coder step)       Repositioning   1/1-Rotation/stopping on   Stopping angle (coder step)           magnets   Fixed speed (rpm)               Limit torque (N · m)               Limit torque tolerance (%)               Maintaining time (ms)               Stopping authorization               Stopping angle (coder step)       Orientation   1/2-Rotation with   Stopping angle (coder step)       by external   detection   Fixed speed (rpm)       cell   2/2-Path to final position   Stopping signal               Stopping authorization               Path (turns)               Stopping authorization               Stopping angle (coder step)       Screwing/   1/3-Screwing   Starting angle (coder step)       checking by   2/3-Unscrewing check   Turret ratio (turns/turns)       unscrewing   3/3-Test path &gt; 0.05 turns   Limit torque (N · m)               Limit torque tolerance (%)               Maintaining time (ms)               Stopping authorization               Fixed speed (rpm)               Limit torque (N · m)               Path (turns)               Stopping authorization               Path traveled               Path not traveled               Stopping angle (coder step)       Square cap   1/3-Rotation/stopping on   Starting angle (coder step)       screwing   magnets   Fixed speed (rpm)           2/3-1/4-turn screwing   Limit torque (N · m)           3/3-Test torque &gt; 1.5 N · m   Limit torque tolerance (%)               Maintaining time (ms)               Stopping authorization               Stopping angle (coder step)               Starting angle (coder step)               Turret ratio (turns/turns)               Path (turns)               Limit torque (N · m)               Limit torque tolerance (%)               Maintaining time (ms)               Stopping authorization               Limit torque reached               Limit torque not reached               Stopping angle (coder step)       Triangular   1/3-Rotation/stopping on   Starting angle (coder step)       cap screwing   magnets   Fixed speed (rpm)           2/3-1/3-turn screwing   Limit torque (N · m)           3/3-Test torque &gt; 1.5 N · m   Limit torque tolerance (%)               Stopping authonzation               Maintaining time (ms)               Stopping angle (coder step)               Starting angle (coder step)               Turret ratio (turns/turns)               Path (turns)               Limit torque (N · m)               Limit torque tolerance (%)               Maintaining time (ms)               Stopping authorization               Limit torque reached               Limit torque not reached               Stopping angle (coder step)       Piston rod   1/3-Screwing   starting angle (coder step)       screwing   2/3-Screwing   Turret ratio (turns/turns)           3/3-Unscrewing   Limit torque (N · m)               Torque regulation factor               Path (turns)               Stopping authorization               Fixed speed (rpm)               Limit torque (N · m)               Limit torque tolerance (%)               Maintaining time (ms)               Stopping authorization               Fixed speed (rpm)               Limit torque (N · m)               Path (turns)               Stopping authorization               Stopping angle (coder step)       Screwing   1/4-Screwing   Starting angle (coder step)       with detection   2/4-Test path &gt; 0.30 turn   Fixed speed (rpm)       of bad   3/4-Unscrewing   Limit torque (N · m)       engagement   4/4-Screwing   Path (turns)               Limit torque tolerance (%)               Maintaining time (ms)               Stopping authorization               Limit path reached         4/4               Limit path not reached         3/4               Fixed speed (rpm)               Limit torque (N · m)               Path (turns)               Stopping authorization               Fixed speed (rpm)               Limit torque (N · m)               Limit torque tolerance (%)               Maintaining time (ms)               Stopping authorization               Stopping angle (coder step)                  
 
         [0061]      FIG. 3  shows an embodiment of a window that may be displayed on the screen  28  of the computer  26  for parameterizing the capping machine. The window  31  includes a region  32  in which the operator is offered different types of cap, namely the cap A, the cap B or the cap C. For the cap A there is proposed a screwing cycle with a high starting torque comprising a high torque starting phase followed by a screwing phase. The definition of the screwing cycle is set out in the region  33  and the operator may define therein the starting angle and the stopping angle expressed in steps of the sensor  10 .  
         [0062]      FIG. 4  shows an embodiment of the next parameterization step employing the window  34  including a region  35  analogous to the region  32  and a region  36  replacing the region  33  in which the operator may define the starting signal, here equal to the starting angle defined by the window  33 , the stopping signal defined by achieving the path, the limit torque, the torque regulation factor, the turret ratio, the limit torque tolerance, the maintaining time, the path and the cycle stopping authorization allowing the motor to execute a stop during the cycle in the event of a malfunction.  
         [0063]     The embodiment shown in  FIG. 5  includes window  37  with a region  38  analogous to the region  32  and a region  39  replacing the region  33 . The region  39  includes tabs for defining the parameters necessary for the screwing phase of the screwing cycle with high starting torque. The tabs are used to define the starting signal, here defined at the end of the preceding phase, the stopping signal defined by the end angle defined in the region  33  of the window  31  from  FIG. 3 , a limit torque, the torque regulation factor, the turret ratio, the limit torque tolerance, the maintaining time and the cycle stopping authorization.  
         [0064]     For each type of cap, the one or more screwing cycles proposed are adapted to the characteristics of the cap. For each screwing cycle, the definition of the general parameters is proposed, namely the starting angle and the stopping angle. For each phase of a cycle, the particular parameters that are pertinent for a phase such as that defined in the above table are proposed.  
         [0065]      FIG. 6  shows an embodiment of a window  40  adapted to be displayed on the screen  28  of the computer  26  and comprising a region  41  for choosing between a predefined screwing cycle or a free screwing cycle. Choosing a predefined screwing cycle allows the operator to fill in only the parameters referred to above, whereas choosing the free option allows the operator to define completely the succession of phases within a cycle. An operator may therefore create a new type of screwing cycle as a function of needed requirements. The region  42  offers a list of predefined screwing cycles available to the operator and the region  43  repeats the name of the preselected cycle before the selection is confirmed, for example by clicking the button  44 . The operator may also define a free screwing cycle based on free or predefined phases.  
         [0066]     The container capping controller is very flexible to use, easy to reparameterize, and has user friendly means enabling an operator to adapt the operation of the capping machine to different types of containers and caps and screwing modes.  
         [0067]     Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.