Abstract:
A method and apparatus for applying labels to cylindrical portions of plastic bottles by in-mold labeling utilizes an indexing label magazine which dispenses labels to first label engaging heads and, following indexing of said label magazine, dispenses labels to second label engaging heads.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a division of Ser. No. 09/145,622 filed Sep. 2, 1998, now U.S. Pat. No. 6,153,143 and is based upon Provisional Patent Application Serial No. 60/068,795 filed Dec. 24, 1997, now abandoned. 
    
    
     The present invention relates a label machine for in-mold labeling of plastic bottles having a circular cross-section configuration, a major portion of which defines a cylinder. In-mold labeling refers to a processes and apparatus for affixing labels to articles such as plastic bottles during the molding process by inserting labels in the recess of a mold section, closing a pair of mold sections around a length of heated, plasticized tubing and expanding such tubing into conformity with the mold cavity defined by the recesses of the closed mold sections thereby causing the label to become affixed to the wall of the newly blown bottle. 
     BACKGROUND OF THE INVENTION 
     The prior art discloses many types of methods and apparatus for accomplishing in-mold labeling of plastic bottles. For example, U.S. Pat. No. 5,350,483, which is incorporated herein by reference, discloses an in-mold labeling insertion apparatus and method according to which there is provided a carriage carrying at least one label holder. The carriage is moved in unison with the mold along a parallel path with the face of the open mold section. The carriage has a label inserting beam extending forwardly therefrom and a label holder operable to (1) receive a label from a label magazine and (2) release the label on the wall of the recess of one of the mold sections upon advancement of the carriage and insertion of the beam and label holder thereon between said open mold sections. Other methods and apparatus for in-mold labeling are shown in U.S. Pat. Nos. 4,639,206; 4,355,967; 4,479,770 and 4,479,771. 
     In the blow molding of plastic bottles, it is desirable to utilize blow molds having a plurality of molding cavities so that a plurality of bottles are molded in each molding cycle of a set of blow molds. The blow molds utilize first and second sections which open and close. Recesses are formed in the mating faces of each of the mold sections. When the mold sections are closed, the recesses cooperate to define cavities in which the bottles are blown. Heretofore there has not been widespread use of in-mold labeling for bottles having a cylindrical body portion, particularly in those situations where it is desired that substantially the entire circumference of the bottle be encircled by labels from the mating mold sections. In order to affix labels which substantially encircle the entire circumference of a cylindrical portion of a bottle, each mold section should have inserted in its mold recess a label having a length equal to the circumferential wall portion of such mold recess. Since two mold sections are normally utilized in blow molding a plastic bottle, the circumferential length of the cylindrical portion of a recess of each mold section will be equal to one-half of the circumference of the cylindrical portion of the bottle being formed. Accordingly, the length of a label to be inserted in each mold section recess will be equal to or substantially equal to one-half of such bottle cylindrical portion circumference. 
     As mentioned previously, it is frequently desirable to utilize blow molds having a plurality of molding cavities aligned with one another with a single tubular parison being blown in each such molding cavity simultaneously with other parisons being blown in their respective cavities while the mold sections are closed therearound. Depending upon the size of the bottles being blown and the type of machine, there may be 2, 4, 6 or even 8 aligned bottles being blown simultaneously. In order to minimize the space occupied by the blow molding machine, it is desirable that each of the cavities be positioned as close to the adjacent cavities as feasible. Such close positioning of the cavities will also minimize the amount of metal required to be utilized in the molds and related equipment and minimize the amount of energy required (1) to move the mold sections between open and closed positions and, (2) depending upon the type of blow molding machine, to move the mold sections laterally from a position beneath an extrusion die orifice for receiving a plurality of tubular parisons to a position at which air is introduced therein to expand the parisons in their respective mold cavities. However, the closeness of the positioning of adjacent mold cavities results in the distance between adjacent mold cavities being significantly less than the length of a label having a length equal to one-half the circumference of the cylindrical portion of bottle being molded. It should be noted that the labels are substantially flat or planar when they are removed from a label magazine by a label transfer mechanism which transfers the labels from the label magazine to the mold recesses. As a result of the length of such labels, when flat, being greater than the distance between adjacent mold cavities, it is necessary that the labels being carried by adjacent transfer mechanisms have overlapping edges. As well be appreciated, such lengths of the labels in relation to the spacing between the mold cavities does not permit the simultaneous utilization of separate label magazines aligned with each mold recess. 
     SUMMARY OF THE INVENTION 
     Under the present invention, a label dispensing magazine having multiple lanes for dispensing labels is provided with a magazine shuttle to shuttle the labels and magazines from a first position aligned with one vacuum label holding head to a second position aligned with an adjacent vacuum label holding head. Assuming that the mold has four sets of mold cavities and the label magazine has two dispensing lanes, the magazine shuttle moves the magazines from a position at which the first and second dispensing lanes of labels are aligned, respectively, with the first and third vacuum label holding head. After t he first an d third vacuum label holding heads remove labels from the first and second dispensing lanes, the magazine shuttle is actuated to move the label magazines to a position such that the first dispensing lane is aligned with the second vacuum label holding head and the second dispensing lane is aligned with the fourth vacuum label holder. The vacuum label holding heads may then be moved into alignment with the respective mold recesses and moved into the recesses to deposit the labels simultaneously in each such recess. The labels supported on adjacent vacuum label holding heads will have overlapped edges with the adjacent labels; however, this does not interfere with the placement by the vacuum label holding heads of their respective labels into the adjacent recesses. 
    
    
     IN THE DRAWINGS 
     FIG. 1 is a schematic top plan view of opposing, multi-lane label magazines and a four head transfer apparatus for each lane, with the first and third vacuum label holding heads shown engaging labels from, respectively, the first and second lanes. 
     FIG. 2 is a view similar to FIG. 1 but showing the second and fourth vacuum label holding heads aligned with the first and second dispensing lanes, respectively, and positioned to engage and withdraw labels therefrom. 
     FIG. 3 is a schematic view showing the label transfer mechanism moved to a position between a pair of open mold halves with each of the vacuum label holding heads in a position ready to insert the labels into their respective aligned mold recesses. 
     FIG. 4 is a view similar to FIG. 3 showing the labels inserted into the mold recesses. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 and 2, there is shown a placer arm assembly generally designated by the numeral  10  positioned between a pair of label magazines generally designated by the numeral  20 . The label magazines  20  are positioned in opposing relationship facing one another, one on each side of the placer arm assembly  10 . Each label magazine  20  has a first lane  21  and a second lane  22  (shown in phantom lines) for holding a supply of labels L, with the end label of each lane  21  and  22  facing the placer arm assembly  10  and being substantially flat and positioned to be withdrawn from that lane of the label magazine  20 . 
     The placer arm assembly  10  includes a pair of longitudinally extending support members  12 , each extending from a base  14  in parallel relationship to one another and parallel to the end labels L of each lane  21  and  22 . Each support member  12  has a plurality of placer arms  16 . As shown, there are four placer arms  16 A,  16 B,  16 C and  16 D on each support member  12 . However, there could be a greater or lesser number of placer arms  16  and a greater or lesser number of lanes  21  and  22  for the labels. Preferably, there should be twice as many placer arms  16  as there are label dispensing lanes  21  and  22 . Each of the placer arms  16  is pivotally mounted on the respective support members  12  for rotatable movement from a retracted position shown in phantom lines in FIG. 1 to a partially extended label pick-up position shown in full lines in FIGS. 1 and 2. Although only placer arm  16 A has been shown in phantom lines in the retracted position, all of the placer arms  16 A,  16 B,  16 C and  16 D are mounted to move together about their respective pivot points from a retracted position to a partially extended position for removing labels from the label magazines (FIG. 2) to a fully extended position for inserting labels in the cavities of the mold sections (FIG.  4 ). 
     Each placer arm  16 A,  16 B,  16 C and  16 D has mounted thereon a vacuum head  18 A,  18 B,  18 C and  18 D. As can be seen in FIGS. 1 and 2, when the placer arms are pivotally rotated on the respective support members  12  from the retracted position to a partially extended position, those vacuum heads aligned with one of the dispensing lanes  21  or  22  will engage and withdraw the end label L therefrom. When the magazines  20  are in the position shown in FIG. 1, the placer arm  16 A and its vacuum head  18 A are aligned with the first lane  21  and the third placer arm  16 C and its vacuum head  18 C are aligned with the second lane  22 . When the magazines  20  are in the position shown in FIG. 2, the second placer arm  16 B and its vacuum head  18 B are aligned with the first label magazine  21  and the fourth placer arm  16 D and its vacuum head  18 D are aligned with the second label magazine  22 . 
     As can be readily seen in FIG. 2, the label L supported on the first vacuum head  18 A has an end portion L 1  which overlaps the end of the adjacent label L about to be withdrawn from the first lane  21  by the second vacuum head  18 B. Additionally, the label L supported on the third vacuum head  18 C has one end L 2  overlapping the label L about to be withdrawn from the first lane  21  and its other end L 3  overlapping the label L about to be withdrawn from the second lane L 2  by the fourth vacuum head  18 D. 
     Each of the label magazines  20  is mounted on a magazine shuttle mechanism generally designated by the numeral  30 . The magazine shuttle mechanism  30  is mounted for reciprocating movement from the position shown in FIG. 1 to the position shown in FIG.  2 . The reciprocating movement is powered by a drive mechanism  31  which is mounted in a fixed position relative to a blow molding machine (not shown). The magazine shuttle mechanism  30  includes first and second longitudinally extending members  32  and  33  and first and second laterally extending members  34  and  35 , each of which extend between and are connected at their opposing ends to the first longitudinally extending member  32  and the second longitudinally extending member  33 . The respective longitudinally extending members  32  and  33  and transversely extending members  34  and  35  are joined together to form a rectangle and provide support for the first label magazine  21  and second label magazine  22 . 
     Extending from opposing ends of the second longitudinally extending support member  33  are a pair of wings  36 . Extending between and rigidly mounted on the wings  36  is rack gear  37 . The rack gear  37  also extends through the drive mechanism  31  and is engaged by conventional means to a gear (not shown) of the drive mechanism  31 . Rotation of the gear of the drive mechanism  31  causes the magazine shuttle mechanism  30  to move from the position shown in FIG. 1 to the position shown in FIG. 2 when the gear is rotated in one direction and from the position shown in FIG. 2 to the position shown in FIG. 1 when the gear is rotated in the opposite direction. In lieu of the drive mechanism  31  and rack gear  37 , the shuttle mechanism  30  could be powered by a linear actuator or cylinder. 
     During the time period in which labels are being removed from the label magazines  21  and  22  as shown in FIGS. 1 and 2, including the period of movement of each of the magazine shuttle mechanisms  30 , the base  14  and support members  12  are maintained in a fixed position relative to the respective drive mechanisms  31 . 
     Beginning with the placer arms  16 A,  16 B,  16 C and  16 D in a retracted position and the other elements positioned as shown in FIG. 1, an actuation mechanism operably connecting the base  14  to the respective placer arms causes each of the placer arms  16 A,  16 B,  16 C and  16 D to rotate relative to their respective support members  12  from the retracted position to the partially extended position shown in FIG. 1, at which position the oppositely disposed vacuum heads  18 A will each be positioned to withdraw a label L from its aligned first lane  21  and the vacuum heads  18 C will each be positioned to withdraw a label L from its aligned second lane  22 . Such withdrawal of the labels L from their respective lanes  21  and  22  will occur upon movement of the placer arms from the partially extended to the retracted position. During such rotation of the placer arms  16 A,  16 B,  16 C and  16 D, each of the heads  18 A and  18 C will carry a label L supported thereon by vacuum, as is well known in the art. With the placer arms  16 A,  168 ,  16 C and  16 D now in the retracted position, the drive mechanism  31  is actuated to move the shuttle mechanism  30  from the position shown in FIG. 1 to the position shown in FIG.  2 . Upon reaching the position shown in FIG. 2, the actuation mechanism causes the placer arms  16 A,  16 B,  16 C and  16 D to again move to a partially extended position so that vacuum heads  18 B are aligned with their respective first lanes  21  and vacuum heads  18 D are aligned with their respective second lanes  22 , at which position each of the vacuum heads  18 B and  18 D engages the end label from its aligned lane. The actuation mechanism then causes the placer arms  16 A,  16 B,  16 C and  16 D to be moved to the retracted position with each of the vacuum heads  18 A,  18 B,  18 C and  18 D having a label L supported thereon. As previously discussed, the labels L supported on heads  18 B will be in overlapping relationship with the labels L supported on heads  18 A and  18 C and the labels L supported on heads  18 C will be in overlapping relationship with the labels L supported on heads  18 B and  18 D. The placer arm assembly  10 , with the labels L supported on the respective vacuum heads, is now ready to be moved to a position between the open halves of a partible blow mold. The mechanism for accomplishing such movement is well known in the art and does not form a part of this invention. 
     Referring to FIGS. 3 and 4, the placer arm assembly  10  is shown positioned between the open sections  41  and  42  of a partible blow mold. Each mold section  41  and  42  has a plurality of recesses  40 A,  40 B,  40 C and  40 D. As can be seen, each of the recesses has a semi-circular cross-sectional configuration such that, when the mold sections  41  and  42  are closed, each of the recesses  40 A,  40 B,  40 C and  40 D defines with its opposing recess  40 A,  40 B,  40 C or  40 D, a cylindrical cavity in which the body portion of the bottle to be formed therein may be blown. Each of the vacuum heads  18 A,  18 B,  18 C and  18 D is aligned such that when the placer arms  16 A,  16 B,  16 C and  16 D are actuated and pivotedly rotated to the fully extended position shown in FIG. 4, the vacuum heads  18 A,  18 B,  18 C and  18 D will have inserted a label L into each of the respective recesses  40 A,  40 B,  40 C or  40 D aligned therewith. Following positioning of the labels L in each of the recesses  40 A,  40 B,  40 C and  40 D, the vacuum to each of the heads is discontinued to release the labels therefrom. The labels L are retained in the recesses  40 A,  40 B,  40 C and  40 D by vacuum introduced through passageways  44  communicating with each recess. The placer arms are then moved to the retracted position and the placer arm assembly is moved to the position shown in FIG. 1 to begin a new cycle of removing labels L from the label magazines  21  and  22  and transferring them to the mold sections  41  and  42 . 
     As can be seen in FIG. 4, each label L has a length which results in it extending the full circumferential extent of the recess  40 A,  40 B,  40 C or  40 D in which it is positioned such that a section taken therethrough will define a semi-circle. As a result, when the mold sections  41  and  42  are closed to define a cavity and a bottle is formed in such cavity, the label L will extend completely around the cylindrical portion of the bottle formed in each of the recesses  40 A,  40 B,  40 C or  40 D. 
     Although the present invention has been described with a mold having four cavities and with an in-mold labeling mechanism having four vacuum heads for withdrawing labels from a dispensing magazine having two lanes of labels, it will be readily recognized that the invention is suitable for use with a mold having a greater or fewer number cavities, of vacuum heads and of lanes. There should be an equal number of vacuum heads as cavities. Preferably, but not absolutely necessarily, there should be at least twice as many vacuum heads as there are lanes of labels in the dispensing magazine. If there are an odd number of mold cavities and vacuum heads, the number of lanes will preferably be at least equal to one-half of the sum of 1+the number of vacuum heads. 
     Modifications will be readily apparent to those skilled in the art. Accordingly, the scope of the present invention should be limited only by the scope of the claims appended hereto.