Abstract:
In a method for applying labels about a bulbous sidewall region of a container, the leading end of the label is joined to the bulbous sidewall region by adhesive bonds above and below a major diameter section of the bulbous sidewall region. While being pressed to the bulbous sidewall region, the label is wrapped about the container, and the trailing end of the label is then adhesively joined to the bulbous sidewall region, or to the overlapped leading end of the label. An apparatus for applying labels about a bulbous sidewall region of a container employs a label transfer drum which cooperates with an adhesive applicator to apply spaced adhesive patches to the leading end of the label above and below a major diameter section of the bulbous sidewall region. The label transfer drum also cooperates with the adhesive applicator to apply a continuous strip of adhesive to the trailing end of the label. An arcuate backing wall with a yieldable surface forms, with the cylindrical surface of the label transfer drum, a passage through which the container rolls while the label is pressed to and wrapped about the bulbous sidewall region of the container.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a process and an apparatus for applying labels to containers. More particularly, the present invention relates to a process and an apparatus for applying labels to the sidewall of containers having a circular cross-section and a sidewall region which is rounded, or bulbous. The process and apparatus of the present invention are particularly applicable to the labeling of polyethylene terephthalate (PET) beverage bottles. 
     Applying a label to containers with a bulbous sidewall region, such as the familiar COCA-COLA bottle, is a particularly difficult undertaking. Labels of flexible sheet material can easily conform to a flat surface or a cylindrical surface. But, for such a label to conform to a bulbous surface, it must be gathered, forming wrinkles, or deformed by stretching or shrinking. 
     In a known technique for applying a label to the bulbous sidewall of a container, the label, of heat shrinkable material, is formed into a sleeve with the overlapping ends secured together. The label sleeve is placed over the container and is then exposed to heat to shrink the label into conformance with the bulbous contour. The manipulation of the label to form the sleeve and then place the sleeve over the bottle requires equipment that is complex and expensive. 
     In a known technique for wrapping a label about a bulbous sidewall of a container, disclosed in U.S. Pat. No. 5,403,416 (Bright et al.), the leading edge of a heat-shrinkable label is adhesively attached to a narrow area at or adjacent to the maximum diameter of the bulbous region of a bottle. The regions of the leading edge of the label at either side of the adhesive bond are not attached to the bottle sidewall. The label is then wrapped about the bottle, and the trailing end is adhesively attached to the bottle or to an overlapped region of the leading end. The bottle, with the label wrapped in sleeve-like form, then moves past hot air jets to shrink the label into conformance with the bottle contour. A problem with this method is that the adhesive can interfere with the placement of the leading edge of the label on the bottle sidewall, due to the location of the adhesive in coincidence with the maximum diameter region of the bottle. Also, the small size of the adhesive bond between the bottle sidewall and leading edge of the label can compromise the stability of the label as it is subsequently wrapped about the bottle. 
     Because of the shortcomings of known methods for applying a label to a bulbous sidewall region of a container, a method, and an apparatus, for carrying out the labeling of such containers, which is not hampered by these shortcomings, would be most welcome. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     Accordingly, it is a primary object of the present invention to provide a reliable method for satisfactorily applying labels to the bulbous sidewall region of containers. 
     It is another object of the present invention to provide an apparatus of relatively simple construction which reliably and satisfactorily applies labels to the bulbous sidewall region of containers. 
     The foregoing objects of the present invention and others as well are fulfilled by providing a process for applying a label bounded by side margins and first and second ends to a bulbous sidewall region of a container of generally circular cross-section, wherein the bulbous sidewall region includes a major diameter section between sections which are of smaller diameter than the major diameter section, comprising the steps of: (a) joining outlying areas along the first end of the label to the bulbous sidewall region at locations within the smaller diameter sections, the outlying areas of the label being separated by a central area along the first end of the label which overlies, and is not joined to, the major diameter section of the bulbous sidewall region; (b) wrapping the label about the bulbous sidewall region until the second end of the label confronts the bulbous sidewall region; (c) joining the second end of the label to the bulbous sidewall region; and (d) forming the side margins of the label against underlying areas of the bulbous sidewall region. 
     The objects of the present invention are also fulfilled by providing a process for applying a label bounded by side margins and first and second ends to a bulbous sidewall region of a container of generally circular cross-section, wherein the bulbous sidewall region includes a major diameter section between sections which are of smaller diameter than the major diameter section, comprising the steps of: (a) applying adhesive patches to the outlying areas only of the first end of the label; (b) applying a continuous strip of adhesive to a major portion of the second end of the label between the side margins; (c) placing the first end of the label over the bulbous sidewall region with the adhesive on the outlying areas confronting the smaller diameter sections; (d) applying pressure at spaced locations within the outlying areas to press the outlying areas against the bulbous sidewall region and produce adhesive bonds where the outlying areas contact the bulbous sidewall region; (e) positioning the bulbous sidewall region and the first end of the label against a yieldable surface; and (f) rolling the container over the yieldable surface while urging the container against the yieldable surface to (1) wrap the label about the bulbous sidewall region until the second end of the label overlaps and confronts the first end of the label (2) cause deformation of the yieldable surface while progressively pressing the label between the bulbous sidewall region and the yieldable surface, (3) effect a progressive conformation of the side margins of the label over the underlying areas of the bulbous sidewall region and (4) press the second end of the label against the first end and the underlying bulbous sidewall region to produce an adhesive bond between the overlapped ends of the label. 
     The objects of the present invention are also fulfilled by providing an apparatus for applying a label bounded by side margins and first and second ends to a bulbous sidewall region of a container of generally circular cross-section, wherein the bulbous sidewall region includes a major diameter section between sections which are of smaller diameter than the major diameter section, the apparatus comprising: means for joining outlying areas along the first end of the label to the bulbous sidewall region at locations within the smaller diameter sections, the outlying areas of the label being separated by a central area along the first end of the label which overlies, and is not joined to, the major diameter section of the bulbous sidewall region; means for wrapping the label about the container until the second end of the label confronts the bulbous sidewall region; means for joining the second end of the label to the bulbous sidewall region; and means for forming the side margins of the label against underlying areas of the bulbous sidewall region. 
     The detailed description of preferred embodiments which follows, to be read in conjunction with the accompanying drawings, will afford a comprehensive understanding of the present invention. However, preferred embodiments of the invention should be regarded as illustrative only, since various modifications within the spirit and scope of the invention may become apparent to persons of ordinary skill in the art who have benefitted from this disclosure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic illustration, in plan, of a labeling apparatus constructed according to the present invention; 
     FIG. 2 is an illustration, in elevation, of a container with a label partially applied to a bulbous sidewall region of the container according to the present invention; 
     FIG. 3 is a partly cross-sectional illustration, in elevation, showing a container, with a partially applied label, positioned between the label transfer drum and the arcuate backing wall; and 
     FIG. 4 is a perspective, partly schematic illustration showing the arrangement of the label transfer drum, the adhesive applicator drum, the adhesive removal drum and a doctor blade according to a second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As illustrated in FIG. 1, a labelling apparatus 10 according to the present invention includes a feed conveyor 12 for a queue of bottles 14 to be labeled, one at a time, an indexing wheel 16 for effecting a uniform separation of individual bottles, a label transfer drum 18, a backing wall 20 having an arcuate surface which confronts and is concentric with the outer surface of drum 18, a label feeder 22, an adhesive applicator assembly 24, a discharge conveyor 26 and a heating station 28. The bottles may, for example, be PET beverage bottles with sidewalls which exhibit some flexibility. The indexing wheel and the label feeder may be of known construction and operation. The label feeder, for example, may be one which cuts individual labels from a web and presents them one at a time to the outer surface of the label transfer drum. 
     A bottle 14 to be labeled, as illustrated in FIG. 2, exhibits a bulbous sidewall region 15 which is of generally circular cross-section and which is defined in part by a major diameter section 15a between sections 15b of somewhat smaller diameter. The label 30 to be applied to the bulbous sidewall region of the bottle has a first end 30a, shown joined to the bulbous sidewall region, a second end 30b and upper and lower side margins 30c, 30d. 
     The first end 30a of the label is joined to the bulbous sidewall region at outlying areas 30e along the first end of the label which overlie the smaller diameter sections 15b of the bulbous sidewall region and are separated by a central area 30g which overlies, but is not joined to, the major diameter section. As illustrated, the outlying areas 30e along the first end of the label are joined to the bulbous sidewall region by discreet adhesive patches. A strip of adhesive 30f, applied to the second end of the label, may be used for joining the second end of the label to the first end. 
     Referring to FIGS. 1 and 3, the label transfer drum 18 may be broadly characterized as a label carrier having a movable surface. The drum includes a cylindrical surface 18a. Passages 18b extending through the cylindrical surface selectively communicate in a known manner with a vacuum established within an interior region of the drum and serve as a means for holding labels to the cylindrical surface. 
     Carried on the cylindrical surface 18a of the drum 18 are at least one set of first and second ridges 19a, 19b which project outwardly from the cylindrical surface. As illustrated in FIG. 1, three sets of ridges are arranged circumferentially about the cylindrical surface of drum 18. The ridges are aligned with the rotational axis of the drum and are circumferentially spaced from each other by a distance which is substantially the same as the distance between the first and second ends of a label. In the direction of rotation of the drum, the first ridge 19a leads the second ridge and will underlie the first end 30a of a label supplied from the label feeder 22. The second ridge 19b will underlie the second end 30b of the label. The ridges may be formed integrally with the drum 18 or, as illustrated, may be provided at the ends of a pad which is fastened to the cylindrical surface of the drum. 
     As best shown in FIG. 3, the first ridge 19a is defined by segments 19a&#39; separated by a recess 19a&#34;. Vacuum is applied through passages 18b extending through the separate segments 19a&#39; and the recess 19a&#34; of the first ridge 19a and through the second ridge 19b ensures that the ends of the label are held to, and conform with, the ridges. The vacuum passages between the ridges ensure that the portion of the label between the ends 30a, 30b is held to the cylindrical surface of the drum and is closer than the ends to the rotational axis of the drum. 
     The adhesive applicator assembly 24 includes an adhesive applicator 25 in the form of a drum with a cylindrical adhesive-applying surface 25a positioned adjacent to the label transfer drum 18. In a known manner, a film of liquid adhesive is applied to the adhesive-applying surface from a source 25b of liquid adhesive. The adhesive applying surface 25a of drum 25 is spaced from the cylindrical surface 18a of the label transfer drum by a small distance which enables the adhesive-applying surface to contact the ridges 19a, 19b, but not the intervening cylindrical surface 18a of the label transfer drum 18, as the label transfer drum rotates. As illustrated, the adhesive applicator drum 25 rotates in a direction which is opposite to the rotation of the label transfer drum. 
     As best shown in FIGS. 1 and 3, the backing wall 20 includes a yieldable surface 21 which is spaced uniformly from the cylindrical surface 18a of the label transfer drum. That is, the yieldable surface 21 is arcuate and concentric with the cylindrical surface of drum 18. The spacing between the two confronting concentric surfaces is a little less than the width of the bottle to be labeled at the major diameter section 15a of the bulbous sidewall region. 
     In the operation of the labeling apparatus, as the label transfer drum 18 rotates, the label feeder 22 presents labels to the cylindrical surface of the drum in a timed sequence which causes the first and second ends of each label to overlie a first ridge 19a and a second ridge 19b, respectively, on the drum 18. The labels are held to the drum 18 and conform to the ridges by vacuum applied through passages 18b. As the labels are carried by the label transfer drum 18 past the adhesive applicator assembly 24, the ends of the labels contact the adhesive-applying surface 25a of drum 25 to thereby effect a transfer of adhesive onto the first and second ends of the labels. Outlying areas 30e along the first end 30a of the label which overlie the segments of first ridge 19a are coated with adhesive, but a central area of the first end of the label, which conforms to the recess 19a&#34; between the segments 19a&#39; of first ridge 19a, does not contact the surface of drum 25 and does not receive adhesive. A continuous strip of adhesive 30f is transferred onto the second end 30b of the label. The portion of the label between the ends, which is held against the cylindrical surface of the label transfer drum, does not contact the surface of drum 25 and does not receive adhesive. 
     The rotation of the label transfer drum 18 is coordinated with the approach of a bottle into the entrance of the arcuate passage 32 formed between the drum 18 and the backing wall 20. That is, as the bottle arrives at the entrance to the passage, coincidentally a first end 30a of a label, overlying a first ridge 19a on the drum 18, moves into contact with the bulbous sidewall region of the bottle. As shown in FIG. 3, the elevation of the recess 19a&#34; between the segments of the first ridge 19a substantially coincides with the elevation of the major diameter section 15a of the bulbous sidewall region of the bottle, and the adhesive-carrying outlying areas 30e along the first end of the label make contact with the smaller diameter sections of the bulbous sidewall region above and below the major diameter section. Because the space between the outer surface of drum and the yieldable surface of backing wall is less than the width of the bottle at the major diameter section, the outlying areas along the first end of the label are pressed by the segments 19a&#39; of the first ridge 19a on drum 18 against the smaller diameter sections of the bulbous sidewall region of the bottle. At these spaced locations of pressure application, the wall of a PET bottle will deform somewhat, and adhesive bonds will be produced. Between the adhesive bonds, the central area along the first end of the label, which overlies the major diameter section of the bulbous sidewall region, is not adhered to the bottle. 
     With the bulbous sidewall region of the bottle pressed between the outer surface of the label transfer drum 18 and the yieldable surface 21 of backing wall 20, continued rotation of the label transfer drum will cause rolling of the bottle over these confronting surfaces in the passage between these surfaces. As the bottle rolls over the cylindrical surface of the drum, the vacuum in the passages 18b which holds the label to the drum is sequentially relieved in a known manner, to permit the label to separate from the drum and wrap around the bulbous sidewall region of the bottle. The bottle rolls over the confronting surfaces of the drum 18 and the backing wall 20, and the label wraps about the bulbous sidewall region of the bottle, until the second end of the label confronts the first end of the label. The adhesive-carrying second end of the label is then pressed by the underlying second ridge 19b on drum 18 against the overlapped first end of the label, producing an adhesive bond beneath the second end of the label. 
     As the bottle rolls over the cylindrical surface of drum 18 and over the confronting yieldable surface 21 of the backing wall, and as the label wraps about the bulbous sidewall region of the bottle, the bulbous sidewall region is progressively pressed into, and deforms, the yieldable surface 21. Concurrently, the bulbous sidewall of a PET bottle will deform somewhat in response to the pressure applied by the confronting surfaces of the label transfer drum 18 and the backing wall 20. As a consequence, the yieldable surface 21 and the areas of the label pressed between the yieldable surface and the bulbous sidewall region of the bottle will conform to the bulbous sidewall region, to an extent which depends on factors including the curvature of the bulbous sidewall region, the magnitude of the pressure and the resistance to deformation which the bottle sidewall and the yieldable surface exhibit. If the curvature of the bulbous sidewall region is quite subtle, for example, the rolling of the bottle over the confronting surfaces of the drum 18 and the yieldable surface 21 may effect a nearly complete conformation of the side margins of the label with the underlying areas of the bulbous sidewall region. 
     After the wrapping and pressing of the label about the bulbous sidewall region of the bottle is complete, continued rotation of the label transfer drum 18 will roll the bottle with the applied label through the exit of the arcuate passage between the drum 18 and the backing wall 20 and will carried away by discharge conveyor 26. The bottles with the applied labels then enter a heating station 28. 
     If the label is of a heat-shrinkable sheet material, a heating station 28 may be employed to achieve the conformation of the side margins of the label with the underlying areas of the bulbous sidewall region. Alternatively, the heating station may be employed to augment the conformation of the side margins achieved by rolling the bottle over the confronting surfaces of the drum 18 and the backing wall 20. The heating station may be of known construction and operation and may, for example, employ nozzles which discharge heated gas onto the side margins of the wrapped label. 
     Adhesive patches may be applied to the first end of the label using another method and apparatus of the present invention which employs modified first ridges on the label transfer drum which underlie the first end of the label and a modified adhesive applicator assembly, illustrated in FIG. 4. Adjacent to the adhesive applicator drum 125 is an adhesive removal drum 134 provided with a wiping element 134a. As the drum 134 rotates, the wiping element 134a will make periodic contact with the adhesive-applying surface 125a of drum 125 and will wipe adhesive from a discreet area 125a&#39; of drum 125. A doctor blade 136 may be positioned adjacent to the adhesive removal drum 134 to engage the wiping element and thereby remove accumulated adhesive. The rotation of drum 125 is coordinated with the rotation of the label transfer drum 118 so that the adhesive-free area 125a&#39; of drum 125 contacts a central area along the first end of a label overlying a first ridge 119a on the label transfer drum. The adhesive-carrying areas of drum 125 above and below the adhesive-free area will contact outlying areas along the first end of the label and transfer adhesive patches to these outlying areas. A circumferentially displaced area of drum 125 will contact the second end of the label and transfer a continuous strip of adhesive to a major portion of the second end of the label. The first ridges 119a on the label transfer drum may be formed like the second ridges 119b, i.e., without a recess, because no adhesive is presented by drum 125 to the central area along the first end of the label. 
     With adhesive patches applied to the first end of the label and a continuous strip of adhesive applied to the second end of the label, the ensuing operations of wrapping and pressing occur just as they do in the earlier described embodiment of the present invention. 
     Variations of the invention may become apparent from the foregoing disclosure. All such variations and modifications which would be obvious to persons of ordinary skill in the art should be regarded as falling within the scope of invention as defined in the following claims.