Abstract:
A capping mechanism comprising an active feeder ( 20 ) device in which caps ( 1, 10 ) are fed actively forward arranged top-to-bottom along a feeding axis ( 30 ), and a hollow rotatable and linearly movable chuck device ( 40 ) arranged at the feeder&#39;s outlet end ( 22 ) and devised to grip a cap and mount said cap to a container opening. The feeder device preferably comprises movable members working in pairs ( 23, 24  and  25, 26  resp.) alternating to influence a row or pile of caps.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a mechanism for capping containers, and more particularly for a mechanism intended for applying screw-type caps on containers. 
     BACKGROUND 
     Commercial distribution and sale of viscous substances are as a rule performed with the substance in question contained in consumer adopted containers in the shape of cans, boxes, TetraPak®-type containers or bottles of different types. Most types of such containers are often in some way recloseable, e.g. by being provided with a lid for closing an opening in the container, or with a cap which can be tightly screwed to a threaded opening of the container and thereby sealing it. Different types of pourable substances that are packed in this way comprise beverages, oils, body and hair products, solvents, toners, corn flakes etc. 
     Consequently, capping is a frequently occurring procedure within the packaging industry, involving a cap being mounted to an opening in a container. This procedure is performed just after the moment when the containers are filled with their content, or at an earlier stage when the containers themselves are produced. A known method for capping of containers comprises the following steps, that generally are conducted in a repeated manner:
         A cap is fed forward laying on a band, standing or rolling in a conduit, in a chute or the like;   A chuck picks the cap up, alternatively the cap is fed to the chuck;   The chuck lifts the cap and brings it to the opening on a container;   The chuck mounts the cap on the container, e.g. by pressure or by rotation.       

     Capped containers are often manufactured in very large volumes, and therefore great effort is often made to increase production pace. A problem with known capping methods is that they comprise a number of time consuming steps, limiting the capping pace. Such steps include the step of moving the chuck from a place where the cap is picked up, to the place where it mounts the cap on the container. Such steps also include the step of waiting for a new cap until the gravity has worked on said cap and caused it to fall into position for being picked up. 
     U.S. Pat. No. 4,222,214 to Schultz discloses a chucking apparatus for applying caps to a threaded portion of a container at a constant torque. In a representative embodiment, caps are supplied to the apparatus by an inclined chute under the influence of gravity to a cylindrical rotating hollow cap guide which guide caps and also conveys rotating power to a chuck device, said chuck device being mounted on a lower portion of the cap guide. Caps are thus center fed to the chuck device, which device comprises a plurality of jaw members, each of which members are pivotable to a cap gripping position. A resilient member is arranged to engage the jaw members in response to fluid pressure, causing the jaw members to pivot to the cap gripping position. The chuck device is subsequently rotated in order to screw the cap gripped thereby onto a container. The required movement of the chuck device is accomplished by lowering the chuck or raising the container or by a combination of both methods. 
     U.S. Pat. No. 1,824,660 to Darner discloses a mechanism for capping bottles, particularly milk bottles. In an embodiment the mechanism is central fed with caps of the press-on type. The caps form a pile inside the mechanism. The mechanism also comprises spiral rods, which, when the mechanism is pressed down, rotates, and sharp edges of cams mounted at the lower end of said spiral rods, separates the lowermost cap from the caps in the rest of the pile. Comprised are also plungers that will press the bottle cap down into a neck of the bottle. 
     U.S. Pat. No. 1,233,469 to Heath discloses a machine for applying caps. In one embodiment caps are applied to receptacle mouths and the machine is spinning or curling the same thereon by means of a rotary cap spinning or curling device. The caps are arranged in a vertical stack or column feeding downwardly by gravity through a head of the machine and aligned with an axis of rotation of said spinning device. 
     U.S. Pat. No. 982,231 to Barry discloses a bottle capping machine of a manual lever-operated type, comprising a magazine tube, a receptacle holder and a capping device mounted on a carrier. 
     U.S. Pat. No. 1495,283 to Chulin et al discloses a screw-lid fitting device for jars comprising a lid receiver with folding flap at top of hollow chuck with lid stops round bottom. When the chuck comes down, upper arms of twin-arm levers disengage from endface of a cylinder. A spring pulls the lower arms of said levers towards each other, gripping the lid and unscrews/screws the lid as the chuck rotates. 
     An object of the present invention is to provide a capping mechanism capable of providing an increased capping rate compared to the prior art techniques. Furthermore, it is an object to provide a capping mechanism which can be used for various different sorts of containers and caps. 
     SUMMARY OF THE INVENTION 
     According to a first aspect, the objects according to the above are fulfilled by a capping mechanism, comprising an active feeder device having means for actively feeding caps forward arranged top-to-bottom along a feeding axis, and a chuck at an outlet end of the feeder, arranged to grip a cap and mount said cap to a container opening. Preferably, said means for actively feeding caps are devised to diametrically engage with a cap present in the feeder device, and to move the cap forward along the feeding axis during engagement. 
     In one embodiment, said feeder device comprises elongated feeder members movable in pairs relative to each other and arranged to alternately hold and release caps arranged between two members in a pair, thereby feeding said caps forward during a hold and move action of at least one pair of said members. Said chuck preferably has a central passage and comprises two or more adjustable chuck jaws arranged to hold the cap during a mounting act. 
     The feeder members preferably comprises two pairs of feeder jaws, each jaw of each said feeder jaw pair being moveable towards the other jaw, wherein one pair of jaws also is moveable in a direction parallel to the feeding axis. 
     According to a second aspect, the objects according to the above are fulfilled by a feeder device for a capping machine, which capping machine comprises a chuck arranged to grip a cap and mount said cap to a container opening, which feeder device comprises means for actively feeding caps forward arranged top-to-bottom along a feeding axis, to an outlet end proximal to the chuck. Preferably, said means for are actively feeding caps are devised to diametrically engage with a cap present in the feeder device, and to move the cap forward along the feeding axis during engagement. In one embodiment said feeder device comprises elongated feeder members movable in pairs relative to each other and arranged to alternately hold and release caps arranged between two members in a pair, thereby feeding said caps forward during a hold and move action of at least one pair of said members. 
     According to a third aspect, the objects according to the above are fulfilled by a method for feeding caps in a container capping machine, comprising the steps of:
         supplying a cap to a feeder device;   engaging the cap diametrically;   feeding the cap, under engagement, along a feeding axis to an outlet position.       

     According to a fourth aspect, the objects according to the above are fulfilled by a capping mechanism, comprising an feeder device for feeding a cap forward, with a bottom of the cap facing a feeding axis, from an inlet position to an outlet position of said feeder device, and a chuck devised to receive a cap from a first side of said chuck at said outlet position, and to mount said cap to a container opening at a second side of said chuck, opposite said first side along said feeding axis, wherein said feeder device is devised to actively feed a cap to said outlet position. 
     Preferably, said feeder device comprises means for engaging about a first portion of a circumference of a cap present in the feeder device, and means for moving the cap forward along the feeding axis to said outlet position during engagement. 
     In one embodiment, said chuck comprises means for engaging about a second portion, different from said first portion, of said circumference when said cap is present in said outlet position. 
     Preferably, said first portion covers substantially diametrically opposing areas of the circumference of the cap. 
     In a preferred embodiment, said feeder device comprises first and second gripping jaws, devised to engage a cap in said inlet position by gripping substantially diametrically opposing areas of the circumference of the cap, and means for moving said gripping jaws along said feeding axis. 
     In one embodiment, cap supply means are devised to supply caps one by one to the inlet position of said feeder device. Said cap supply means are preferably devised to supply caps to the inlet position in a supply direction which has an angle to said feeding axis. In a more specific embodiment, said cap supply means are devised to supply caps to the inlet position in a supply direction which is substantially perpendicular to said feeding axis. Preferably, said cap supply means are devised to supply caps arranged side-by-side along said supply direction to the inlet position. 
     In a preferred embodiment, said feeder device comprises elongated feeder members movable in pairs relative to each other and arranged to alternately hold and release a cap arranged between two members in a pair, thereby feeding said cap forward during a hold and move action of at least one pair of said members. 
     More specifically, in such an embodiment said feeder members may be devised to grip and move two or more caps at a time, which caps are successively supplied to said inlet position and fed top-to-bottom by said feeder members to said outlet position. 
     According to a fifth aspect, the objects according to the above are fulfilled by a method for capping containers, comprising the steps of:
         supplying a cap to an inlet position of a feeder device such that said cap is arranged with a bottom of the cap facing a feeding axis;   gripping the cap by means of the feeder device engaging about a first portion of a circumference of the cap;   feeding the cap, under engagement, along said feeding axis to an outlet position;   receiving the cap from a first side of a chuck at said outlet position;   gripping the cap by said chuck; and   mounting the cap to a container opening at a second side of said chuck, opposite said first side along said feeding axis.       

     Preferably, said chuck grips said cap by engaging about a second portion, different from said first portion, of said circumference. 
     Furthermore, said first portion preferably covers substantially diametrically opposing areas of the circumference of the cap. 
     According to a sixth aspect, the objects according to the above are fulfilled by a method for feeding caps in a container capping machine, comprising the steps of:
         supplying a first and a second cap to a feeder device, wherein said caps are arranged top to bottom;   engaging the caps diametrically;   feeding the caps, under engagement, along a feeding axis until the first cap reaches an outlet position;   gripping the first cap in the outlet position with a chuck;   removing the first cap from the outlet position by said chuck; and   feeding the second cap, under engagement, along the feeding axis until it reaches the outlet position.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention, including further features, aspects and advantages will become better understood from the following description with reference to the accompanying drawings, on which: 
         FIG. 1  shows a capping mechanism according to a first embodiment of the present invention; 
         FIG. 2  shows a detail of a feeder device of the mechanism in  FIG. 1 , with one feeding jaw removed for enhanced clarity; 
         FIG. 3  shows the mechanism of  FIG. 1  together with a container; 
         FIG. 4  shows the embodiment of  FIG. 1  from the side; and 
         FIGS. 5–9  schematically illustrate a second embodiment of a capping mechanism according to the invention, and different method steps of a capping process according to this embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIGS. 1 to 4  illustrate a first embodiment of the present invention. Referring to  FIG. 1 , caps  1  are supplied from above, oriented with the bottom (inside) facing left, side to side after each other, to an inlet opening  21  of a feeder device  20 . The caps  1  are placed in a feeder device  20  in an inlet position  21 . From this inlet position  21  caps are fed forward (left in the drawing) by the device  20 , in a piled arrangement in a pipeline kind of process. A piled arrangement is not necessarily a vertical pile, it means rather that the caps  1  are arranged top-to-bottom, i.e. the bottom of one cap faces the top of the preceding cap, according to the drawings. Furthermore, the caps are conveyed through the feeder with the bottom facing the direction of transportation. The feeder device  20  is also provided with an outlet end  22 . A feeder mechanism  23 – 26  is provided within the feeder device  20 , devised to actively feed caps from the inlet end  21  all the way to the outlet end  22  in a controllable pace. This feeder mechanism functions by actively gripping each cap present therein, preferably diametrically, and then displacing the cap by moving the gripping point towards the outlet end  22 . In one embodiment the feeding device comprises means for bringing caps forward with the help of a helical movement. This can be achieved by arranging two or more rotatable shafts parallel to the feeding axis  30  and spaced from each other such that they engage a cap present there between. The shafts can be provided with threads or the like, such that rotation of the shafts will result in the caps being forced forward in the feeding direction. In another embodiment the feeding may be provided by endless belts engaging diametrically opposite sides of a cap, and running in the feeding direction. 
     In the shown embodiment, however, said feeder device  20  comprises two pairs of members in the form of feeding jaws. A first pair  23 ,  24  ( 24  not shown in  FIG. 1 ) and a second pair  25 ,  26 , respectively. In this embodiment, each pair of feeding jaws is arranged to grip caps present there between, preferably with a grip where said jaws make contact on diametrically opposite sides of caps. The first pair is also shiftable back and forward in the direction of a feeding axis  30 . The two pairs of feeding jaws are arranged approximately 90° in relation to each other around the feeding axis  30 .  FIG. 4  illustrates, as seen from the inlet end  21 , the arrangement of the feeding jaws  23 – 26  about the feeding axis  30 . The feeding jaws grip and release by relative displacement towards and away from each other, respectively. Said jaws can grip and hold caps with the mere use of friction force, but preferably utilises a number of lugs  27  arranged for this purpose. The lugs are arranged at equidistant positions along the feeding device  20 , the distance between which is selected to fit the cap size in question. These lugs  27  will correct minor errors in alignment of the caps and prevent them from jamming the feeder device  20 . 
     The shown embodiment is devised to feed caps according to the following general principle:
         The first pair of feeding jaws  23 ,  24  grips the caps in the feeder including the one in the inlet position, while the second pair of feeding jaws  25 ,  26  subsequently releases their grip around the caps in the feeder  20 ;   The first pair of feeding jaws  23 ,  24  moves forward, bringing the caps forward one positional step in the feeder along the feeder axis towards the outlet end  22 ;   The second pair of feeding jaws  25 ,  26  grips the caps in the feeder, and subsequently the first pairs of feeding jaws  23 ,  24  releases its grip around the caps;   The first pair of feeding jaws  23 ,  24  is brought back along the feeding axis to enable said jaws  23 ,  24  to stand by for gripping the caps and make the next cap in the inlet position  21  part of the piled arrangement of caps in said feeder.       

     A cap  10  that has reached the outlet end  22  is solely held by the second pair of feeding jaws  25 ,  26 , and is still turned so that its bottom side preferably is facing outwards from the outlet end  22 . With bottom side is meant the side that is to be mounted to a container opening.  FIG. 1  further illustrates how a chuck  40  is arranged at the output end  22 , and provided with a central passage for the caps. The chuck preferably comprises at least two chuck jaws  41 ,  42  movable in a radial direction and said chuck jaws are so devised that they can grip the cap  10  at the same time as said cap is gripped by the second pair of feeding jaws  25 ,  26  according to the drawing. The chuck  40  is furthermore devised to rotate, for the purpose of fixing it to a container opening. For this rotation the chuck is driven by a suitable transmission of a drive motor (not shown).  FIG. 1  shows the feeder device  20  in a position subsequent to the last of the aforementioned steps. When the first pair  23 , 24  of feeding jaws is brought back, opposite the feeding direction, the chuck  40  is displaced in the same direction along the axis  30 , to a position radially outwardly of the cap  10  held by the second feeding pair  25 , 26  in the outlet end  22 . Once in the position outside the cap  10 , the chuck  40  grips the cap  10  by a relative inward displacement of the chuck jaws  41 , 42  towards the axis  30 , thereby assuming the position shown in  FIG. 1 . When the chuck has gripped the cap  10  the second pair of feeding jaws  25 ,  26  are moved outwardly releasing their grip around the cap. This step also forms a part of the feeding procedure described above. The drive motor mentioned above is preferably a servo drive motor capable of bringing the chuck  40  to an angular position that makes room for the second pair of feeding jaws  25 ,  26  in the gaps between the chuck jaws  41 , 42 , when the chuck returns to fetch the next cap fed to the outlet end  22 . 
       FIG. 3  illustrates the mounting of a cap  10  to a container  50 , by means of the chuck  40 . The container  50  is arranged with an opening  51  in close proximity to, and in alignment with, the outlet end  22  and axis  30 . This is advantageous because the chuck  40  then only has to move the cap a minimum distance from the outlet end  22  towards the container opening  51 , clearing it from the outlet end position to which a new cap is fed. This distance is completely one-dimensional and aligned with the feeding axis  30 . The power for this linear motion may come from a linear motor, or from a suitable deflection of power from the rotation drive motor. The radial motion of the chuck jaws  41 , 42  can for example be produced by way of linear motors or pneumatics, in a manner well known to the skilled person. 
     The chuck  40  is brought into a position so that during the mounting of the cap, said chuck can rotate freely from the pair of feeding jaws  23 ,  24  and  25 ,  26 , at the same time as room has been left at the outlet end  22  at an outlet position in the second pair of feeding jaws  25 ,  26 , for a new cap to be fed forward to the outlet end  22 . After a completed mounting the chuck is brought back to the position shown in  FIG. 3 , and said chuck is able to repeat the described process for the next cap that has been brought into place ready to be fed to the chuck. A new container is in that connection preferably fed forward to the position shown in  FIG. 3 . 
       FIGS. 5 to 9  illustrate a second embodiment of the present invention. In this embodiment, the feeder device is of a simpler design than in the previous drawings. In this embodiment, caps are supplied from above, oriented with the bottom (inside) facing left, side to side after each other, to an inlet position  121  of feeder device  120 . The caps are e.g. supplied from a chute (not shown). In  FIG. 5  a first cap  101  is placed in the inlet position  121 . From this inlet position  121 , cap  101  is subsequently fed forward (left in the drawing) by the device  120  to a chuck  40 , with the bottom of said cap  101  facing the direction of transportation. A feeder mechanism  123 , 124  is provided within the feeder device  120 , devised to actively feed caps from the inlet position  21  to an outlet position  122 , at which outlet position said chuck grabs the cap. This feeder mechanism functions by actively gripping each cap present therein, preferably diametrically, and then displacing the cap by moving the gripping point towards the outlet position or end  122 . In the embodiment of  FIGS. 5 to 9 , the feeder mechanism of said feeder device  120  comprises a pair of gripping members or jaws  123 , 124 . The pair of gripping members are arranged to grip a cap present there between on diametrically opposite sides of the cap. As is illustrated in  FIG. 5 , a front end portion of each gripping member is devised with a shoulder-like gripping portion  125  facing the other gripping member. In the drawing, only the gripping portion  125  of the first gripping member  123  is clearly shown, but it should be noted that the second gripping member  124  has a corresponding structure facing gripping member  123 . Cooperating gripping portions  125  are devised support a cap placed in the inlet position  121  by means of the shoulders of the gripping members, such that the cap will not twist but rather assume a position with its bottom facing the feeding axis  30 . The gripping portions may optionally include further support structures, not only devised to support side and top portions of the cap, but also a front portion. For instance, the gripping portion  125  may include a recessed portion in the respective gripping member, providing shoulder edges both towards the top and bottom of a cap present between the gripping members. With such a solution, the gripping members must be capable of moving apart to an extent where the cap can be released forward along the feeding axis, when the cap has been fed to and gripped by the chuck, according to  FIG. 8  described in more detail below. Alternatively, the capping mechanism may include a separate forward stopping member devised to prevent a cap supplied to the inlet position  121  to fall forward, which separate forward stopping member is withdrawn once the gripping members have engaged and gripped the cap. 
       FIG. 5  illustrates a starting position, in which the first cap  101  is positioned in the inlet position  121 . A cap stopping member is preferably arranged below the first cap  101 , if the device is oriented as illustrated, such that the first cap  101  rests towards said cap stopping member. The gripping jaws  123 , 124  are located at a distance or an angle from each other, such that the distance between gripping portions  125  is larger than the diameter of cap  101 . Preferably, the next cap  102  is does not rest on the first cap  101 , but is rather fixed in the illustrated position by cap locking means (not shown). The third cap  103 , and possibly further caps above the third, are rested one on the other, on the second cap  102 . The gripping jaws and the first cap  101  are placed behind chuck  40 . 
       FIG. 6  illustrates a second position, in which the gripping jaws have been placed in diametrical contact with the cap  101 . This is achieved either by displacing the gripping jaws towards each other, or by pivoting them, such that the gripping portions  125  are brought closer to each other. 
       FIG. 7  illustrates how the feeder device  120  has been displaced forward towards the chuck, such that the first cap  101  has been brought into an outlet position of the feeder device where it is to be handed over to the chuck. As indicated before, the second cap  102  is maintained in the previous position by cap locking means. As mentioned, the gripping jaws  123 , 124  of the feeder device  120  are diametrically arranged in relation to a cap positioned there between. Furthermore, as is also illustrated in the drawings, the gripping portions  125  of the gripping jaws each cover only a first portion of the circumference of the cap. The chuck, on the other hand, comprises at least two chuck jaws  41 ,  42  which are displaceable in a radial direction from a centre feeding axis  30 , see  FIG. 5 . These chuck jaws each cover a second portion of the circumference of the cap. The first and second portions of the circumference are complementary, and together they cover, at most, the entire circumference, though preferably less. Furthermore, when the capping mechanism is arranged in the position as shown in  FIG. 7 , the chuck jaws are rotatably oriented such that the gripping jaws  123 , 124  and the chuck jaws  41 , 42  face different portions of the circumference of the cap. This way, both the gripping jaws  123 , 124  and the chuck jaws  41 , 42  are capable of gripping the cap, preferably perpendicularly in relation to each other. 
       FIG. 8  illustrates how the chuck jaws  41 , 42  have been displaced radially inwards, to grip the first cap  101 . Once the cap  101  has been gripped by the chuck jaws, the gripping jaws  123 , 124  of the feeder device  120  release their grip of the cap, and the gripping jaws are brought back to the position shown in  FIG. 5 . 
       FIG. 9  illustrates application of the cap on a container opening (not shown). The cap  101  is applied by rotation of chuck  40 . At the same time, the chuck is preferably displaced forward towards the container opening at a rate corresponding to the pitch of cooperating threads on the inside of the cap and on the outside of the container opening, respectively, such that the container opening can be maintained in a substantially fixed position during application of the cap. In a preferred embodiment, rotation of chuck  40  also unlocks the cap locking means, such that the subsequent cap  102  enters the inlet position  121 . When the first cap  101  has been applied, chuck  40  returns the position of  FIG. 6 , preferably by first releasing its grip of the first cap  101 , thereafter by rotating to the perpendicular orientation in relation to the gripping jaws  123 , 124 , and finally by a backwards linear translation. The capping mechanism is then returned to the state illustrated in  FIG. 5 , and the process is thereafter preferably repeated, including the steps of removing the capped container opening and placing a new container opening in front of chuck  40 . 
     Several advantages are achieved with the present invention. It should be noted that many of the above actions performed by the participating parts can take place simultaneously, forming an efficient pipeline, or assembly-line way of operation of the capping mechanism, enabling a high capping pace. The feeding and the transport in the chuck of the cap take place in one and the same dimension, which results in a simple and thereby fail-safe process. Moreover, the displacement of the chuck  40  is very short, in the described embodiment basically not longer than the height of a cap or the pitch of the threaded portion of the cap, which enables an increased pace of capping compared to a solution in which the cap has to be picked up by the chuck and be transported sideways, compared to axis  30 , to the container opening  51 . The feature of feeding the caps top-to-bottom also enables, in most cases, a more compact design of the capping machine including the feeding device. 
     A technical effect of the present invention is that the feeding of caps does not rely on gravity. The supply of caps to the feeder device may rely on gravity, but may alternatively be achieved by actively supplying the caps by force to the feeder device. This means that the feeding apparatus, combined with a chuck, can be used for applying caps in any direction. It is well known that there are several types of containers which have side-mounted openings, e.g. the type illustrated in  FIG. 3 , suitable for water closet cleaning fluids. This type of container cannot be capped by any of the aforementioned gravity-dependent solutions of the prior art. The use of gravity feeding further has the disadvantage that flat caps tend to jam in a feeding pipe if they are dropped top to bottom. Furthermore, some types of caps are conical, such that the top of one cap fits into the bottom of another cap. Both the weight of the caps and the fact that they are repeatedly dropped and halted, may cause them to engage and catch on to each other when arranged piled top to bottom. 
     In the shown embodiment, the cap is mounted by rotation into threaded engagement with the container opening  51 . However, it could of course also be advantageous to use the present invention on a push- or press-cap container design, suitable for a capping device where the chuck is arranged for example to push the capsule on to the container opening. A person skilled in the art also realises that the container on to which the cap is mounted is not necessarily a complete container, but alternatively only that part of the container on to which the container opening is formed, e.g. a bottle neck. The foregoing has described the principles, preferred embodiments and modes of operation of the present invention. However, the invention should not be construed as being limited to the particular embodiments discussed above. It should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope of the present invention as defined by the following claims.