Field of the Invention

This application relates to a method and apparams of labeling an article having a convex surface located between top and bottom portions of the article.

Background of the Invention

Numerous types of articles and containers are labeled by wrap around methods and followed by heat shrinking the label onto the container. Some of these containers present convex surfaces to be labeled. Such articles can include containers such as a mayonnaise jar as well as a Coca-Cola bottle.

One proposed mediod and apparams for labeling an article with a convex surface is disclosed in United States Patent No. 5,403,416 to Bright et al. This patent discloses a mediod and apparams for attaching the leading edge onto the sector of maximum diameter of a convex surface and tiien wrapping the label around the convex surface so that only the sector of maximum diameter retains the label. The label then is moved to a heat shrink apparams where a belt drive engages d e container and spins it. This heat shrink apparams includes a conventional leister gun arrangement which ejects a very harsh hot air flow through a fan-shaped nozzle against the section of maximum diameter. As me article moves through the apparams, jets of hot air are blown above and below the sector of maximum diameter. The jets of air are blown progressively along the convex surface above and below d e area of maximum diameter to heat shrink die label.

It is believed diat diis type of mediod and apparams induces wrinkles widiin die label and places a concentrated amount of heat in a specific location of the label. Thus, it is possible to damage me seam formed by me trailing edge overlapping die leading edge or die trailing edge being adhered to die convex surface. This heat is focused by d e leister gun fan shaped nozzles and creates problems in label wrapping. Additionally, tiiis apparams and mediod requires a vast amount of

specialized adjustment of die angle in which the jets of hot air are directed on the labels as well as specialized adjustment of the temperamre of the hot air. Also, the speed of article rotation must be accurate to insure proper heat shrinking of the label. All these parameters must be balanced with each other. As a result, labeling is very difficult.

Additionally, many convex surfaces on containers are not true convex surfaces, but have an upper or lower convex portion, with one portion having greater convexity than the other portion. For example, in one standard Coca-Cola Bottle to be labeled, the upper convex portion above the area of maximum diameter has a greater convexity than the lower convex portion. Thus, it is not necessary to use a harsh heat treatment with jets of air blown through a leister gun arrangement as in the aforementioned '416 patent.

Also, it is desirable to heat shrink the label onto a convex surface without a leister gun arrangement or other system that uses harsh jets of hot air directed from one side only onto a spinning article. Spinning an article requires additional mechanical mechanisms as well as specialized and accurate control over timing, which may be difficult to obtain in harsh operating conditions. Thus, the combination of maintaining the proper nozzle angle, article feed speed, rotational velocity and overall applied heat, make the method and apparams disclosed in the '416 patent difficult to operate in commercial applications.

Summary of the Invention

The present invention now provides a metiiod and apparams for labeling an article convex surface without requiring article rotation during heat shrinking of the article. The present invention also has a less harsh heat treatment than that presented by jets of hot air through a leister gun arrangement with fan shaped nozzles as disclosed in the '416 patent.

In accordance with the present invention, the leading edge of a heat shrinkable film is attached onto the sector of maximum diameter of a convex surface. The fdm is wrapped about tiie article and the trailing edge is secured onto the sector of maximum diameter, or onto the leading edge such that the film

material as a whole is retained only on the sector of maximum diameter. The film material is then heat shrunk onto the convex surface by moving the article without a spinning motion by blowing hot air from opposing sides generally onto the convex surface. The article is moved in a substantial linear path of travel while heat shrinking the film material.

In one aspect of the invention, the article has top and bottom body portions and a convex surface witii a lower convex portion and a upper convex portion positioned respectively above and below the sector of ma imum diameter. On one convex portion, e.g., in the present embodiment, the upper convex portion, has greater convexity than the convexity of the lower convex portion. Naturally, the lower convex portion could have greater convexity than the upper portion. Hot air is blown from opposing sides generally onto the area of maximum diameter, followed by blowing hot air from opposing sides onto the convex portion having greater convexity, progressively from the area of maximum diameter onto die convex portion of greater convexity as the article is moved.

In one aspect of the invention, articles having an upper convex portion of greater convexity are moved through a heat shrink mnnel. The mnnel has opposing ends and two opposing sides forming two, substantially parallel, inner sides, and a longimdinally extending, substantially horizontal hot air slot (or vent) positioned on each inner surface dirough which hot air is blown onto the article moving through the tunnel. Each slot is inclined upwardly from die horizontal and positioned such that hot air is blown from the two opposing sides onto the sector of maximum diameter. Then air is blown onto the upper convex portion progressively upward from the area of maximum diameter onto me upper convex portion as the article is moved.

In still anotiier aspect of the present invention, the heat shrink tunnel comprises a first tunnel portion where the slots are inclined upwardly for heat shrinking the label onto the article, and a second mnnel portion where the slots are horizontally disposed for insuring a tight shrink fit of the label about the article.

In still another aspect of the invention, the article has a lower body portion which presents an area of maximum diameter to form a smaller diameter

portion between the convex surface and the maximum diameter area of the lower body portion. A rotatable label drum retains heat shrinkable thin film labels thereon and die article engages the label drum for transferring the film from the label drum onto the article. The label drum is configured to engage the convex sector of maximum diameter, and the lower portion of maximum diameter on the lower body portion while leaving substantially disengaged the area between the convex surface and the maximum diameter of the lower body portion. Pressure is applied onto the areas of maximum diameter located on die convex sector, and the lower portion of the article, to maintain article stability against the label drum during label wrapping. This pressure means can comprise roll-on-pads.

Brief Description of the Drawings

The foregoing and other objects and advantages of the present invention will be appreciated more fully from the following description, with references to the accompanying drawings in which:

Figure 1 is a isometric view of the conveyor moving an article into the heat shrink tunnel for heat shrinking the label about the convex surface of the article.

Figure 2 is a plan view of a label machine that can be used in the present invention.

Figure 3 is a representative article (showing a beverage container) having the thin film label material heat shrunk about the convex surface.

Figure 4 is a schematic diagram of the heat shrink tunnel showing two tunnel portions, with the first tunnel portion having an inclined slot for blowing air progressively upward along the upper convex portion and a second tunnel portion having a substantially horizontally aligned slot.

Figure 5 is an end view of tunnel one of Figure 4 taken along line 5- 5 of Figure 4.

Figure 6 is a schematic illustration showing a roll-on-pad engaging the sector of maximum diameter of the convex surface, and a second roll-on-pad engaging the area of maximum diameter on the lower body portion.

Detailed Description of the Invention

The present invention now allows wrap around labeling and heat shrinking of a label onto a convex surface without spinning the article during heat slirinking, and without the use of harsh jets of air such as from a leister gun arrangement, such as disclosed in United States Patent No. 5,403,416. The present invention heat shrinks the film material onto a convex surface by moving the article without spinning motion while blowing hot air from opposing sides generally onto the convex surface. In one aspect of the invention the convex surface has upper and lower convex portions, with one of the convex portions having greater convexity than the other convex portion. The hot air is initially blown onto the convex sector of maximum diameter and tiien progressively blown onto the portion with greater convexity. The use of opposing sources of hot air provides a less harsh environment and does not require the spinning of the article during the heat treating step.

Referring to the Figures, and more particularly to Figure 1, there is shown an article 10 entering a heat shrink mnnel, indicated generally at 12. The article 10 exits the mnnel 12 having the label heat shrunk onto the convex surface 14 of the article 10. The type of article 10 which will be described in the present application is illustrated in Figure 3, and shows one type of Coca-Cola bottle which can be used and labeled with the method and apparams of the present invention. The article 10 will be described in this rest of the application as a container, since it is depicted as a fluid-beverage container.

The container 10 includes top and bottom body portions, 16, 18 and a central vertical axis 20. The convex surface 14 to be labeled is located between die top and bottom body portions, 16, 18 and presents a sector of maximum diameter 22. In the present invention, the convex surface 14 has a lower convex portion 24 and an upper convex portion 26. The upper convex portion 26 has greater convexity than the convexity of the lower convex portion 24 as shown by the dimension "X plus Y" located between the point of maximum convexity on the upper convex portion 26 and the tangent line 28. This is compared to the smaller dimension "X" corresponding to the spacing between the tangent line 28 and the

point of maximum convexity on the lower convex portion 24. As illustrated in Figure 3, the upper convex portion 26 has much greater surface area than the lower convex portion 24.

The upper body portion 16 includes a generally arcuate tapering section 30 which terminates in an opening 32 on which a cap could be screwed. The lower body portion 18 includes an area of maximum diameter 34 so that the portion between the convex surface 14 and the area of maximum diameter 34 on the lower body portion 18 is of lesser diameter as shown in Figure 3. In one embodiment, the maximum diameter 34 is slightly greater than die maximum convex diameter 22. Both the upper and lower body portions are fluted as illustrated generally at 36. The containers 10 typically are formed from a plastic material such as PET or polyetiiylene, or other material known to those skilled in the art. The containers could be formed from glass.

The labels "L" which are applied onto die convex surface typically are rectangular configured and have respective leading, trailing and side edges 38, 40, 42 as shown in Figure 3. Labels 'L' are formed from a tiiin film layer material and are heat shrinkable. Typically, the labels are about 0.001 to 0.003 inches thick. The label material could be formed from polyethylene, polyvinylchloride or numerous other types of plastic, heat shrinkable, film material known to those skilled in the art. The label can have printed indicia corresponding to identifying, commercial logos and otiier information. Referring now to Figure 2, there is illustrated a representative labeling machine, indicated generally at 50, which can be used for cutting labels L from strip material 52 and placing the cut labels onto a label drum 54 for transport into engagement with a container 10, where the leading edge 38 is first transferred onto the convex surface 14 of the container, wrapped about the container 10, and then moved by a conveyor 56 to a heat shrink tunnel 12. Such labeling machine can be a series 4500 or 6500/6700 manufactured by Trine/CMS Gilbreth Packaging Systems, Inc. of Turlock, California. Typically, the containers are filled and capped during labeling. The label drum includes a resilient surface on which labels are retained.

Figure 2 shows such a labeling machine 50 that is mounted on a mounting surface or generally flat table top 58. A link belt conveyor 56 moves the containers toward die labeling machine 50 in the direction of arrow 60. The labeling machine 50 is designed to apply labels to containers 10 that have a broad range of sizes, or diameters for cylindrical containers. Among this spectrum of container sizes that the labeling machine 50 can process is a mid-size container, such as a 16 ounce container tiiat is intermediate between die maximum and minimum container sizes the machine 50 will label. The machine can label other container sizes such as a two or three liter or six ounce container.

Containers 10 on the conveyor 56 are first received in die labeling machine 50 by a starwheel assembly 62, which moves the containers 10 in the direction of the arrow 60 toward a roll-on-pad assembly 64. In cycling die containers 10 through the labeling, the starwheel assembly 62 brings the containers past the roll-on-pad assembly 64, which imparts a counter-clockwise rotation to these containers, in the direction of arrow 66. The roll-on-pad assembly 64 has a generally arcuate guide 68 tiiat is covered witii resilient padding 70. The padding 70 grips the containers 10 and forces them to rotate in the desired direction. The roll-on-pad assembly 64 typically is removably mounted on die table top 58 by means of manually operated toggles 72.

The roll-on-pad assembly 64 also forces die container 10 against the surface of the label drum 54, which draws vacuum onto die label for retaining the label onto the drum surface. Because of the unique container configuration shown in Figure 3, the label drum surface includes a cut-out portion 74 forming upper and lower portions 76, 78 above and below die cut-out 74 to engage die convex sector of maximum diameter 22 and die area of maximum diameter 34 on die lower body portion 18. The roll-on-pad assembly 64 includes an upper roll-on-pad 80 for engaging the convex sector of maximum diameter 22 on die container 10 and a lower roll-on-pad 82 for engaging the area of maximum diameter 34 on the lower body portion 18. The roll-on-pads 80, 82 press against the container 10. The lower roll-on pad 82 can compress the lower body portion 18 so that the area of maximum diameter 34 on the lower body portion 18 is equal to die sector of

maximum diameter 22 on the convex surface 14. The two roll-on-pads 80, 82 also provide stability to the container during labeling.

A roll of labels 90 provide a web 92 of labels that is drawn through a feed roller system 94 to a cutter 96. In accordance with another characteristic of the invention, the cutter 96 is placed close to die cylindrical label drum 54. The label drum 54 has a perforated surface for drawing vacuum. The web 92 is drawn from the feed roller system 94 and is pressed against a perforated surface of a cylindrical cutter drum 98 because a vacuum is drawn within the cutter drum 98. The cutter drum 98 rotates and a cutter blade 100 protrudes from the cylindrical surface of the cutter drum 98 to press against the web 92. Vacuum, or lower air pressure, within the cutter drum 98 and the label drum 54 are provided by means of a conventional low pressure air system that is not shown in the drawing. A stationary cutter blade 102 is placed as close as possible to the surface of the cylindrical label drum 54. As the rotating blade 100 and the stationary blade 102 come into registry with each other, the portion of the web 92 that protrudes beyond the nip of these two blades is sheared from tiie web by the action of the blades 100 and 102. The label L, which was sheared from the web 92 by the cutter blades 100 and 102, is temporarily pressed against the perforated surface of the label drum 54 because of the vacuum that is drawn widiin die drum.

The spatial relation between the stationary knife blade 102, the blade 100 on die cutter drum 98 and the surface of the vacuum drum 54 is such that at the time the label L in the web 92 is sheared from tiiat web, about 50% or more of the surface of the label is drawn against the perforated drum surface. It has been found, in accordance with invention, that the diameter of the cutting drum 98, heretofore critical with respect to the positioning, skewing or mispositioning of the label L on the vacuum drum 54, is of no significance if about 50% or more of tiie label L is pressed against the perforated surface of the vacuum drum 54 at the time the label is sheared from the web 92.

Further in this regard, it should be noted that the surface speed of the cutter drum 98 is slightly greater than the speed of the web 92. While, in turn, the surface speed of die vacuum drum 54 is somewhat greater than that of the

cutter drum 98. The web 92 is, in this manner, constantly under tension tiiroughout its length until the web is actually cut, causing the web, before cutting, to slip relative to both the cutter drum 65 and die vacuum drum 54. Because die majority of the label is on the vacuum drum 54 before the cut is made, this enables the label L to stay in the same position on the vacuum drum 54 after the cut has been made regardless of operative speed. In this circumstance, even a small label can be cut with the vacuum drum 54 being in full control of the label at the time the label is sheared from tiie web 92 to assure proper positioning of the label on the drum 54.

The severed labels (not shown in Fig. 1) are rotated in the direction of arrow 104 on die label drum 54 to a glue applicator 106. Glue is applied to the surface of the label that is exposed on d e label drum 54 by die glue applicator 106. The label drum 54 rotates the leading edge of die glued label until the leading edge of die label is approximately in alignment with a line 108 between the rotational axis of the vacuum drum 54 and ti e starwheel assembly 62.

The line 108 also coincides with die termination of an arcuate in¬ feed guide 110. The container 10 in cusp 112 of the starwheel assembly 62 is pushed by the starwheel into engagement with the leading edge of the label so that the leading edge of die label engages d e sector of maximum diameter on the convex surface. The label L then wraps itself around die container 10, so that the label is engaged to die convex sector of maximum diameter 22 on die convex surface 14. This container 10 continues its counter-clockwise rotation.

After having been labeled, the container then continues on the conveyor 56 to die heat shrink tunnel 12 illustrated in Figure 1 and schematically in Figures 4 and 5. As shown in Figures 1 and 4, the heat shrink tunnel 12 is formed from a first heat mnnel portion 120 and a second heat tunnel portion 122. Each heat tunnel portion 120, 122 is in die present embodiment a forty (40) inch forced air heat tunnel manufactured by CMS Gilbreth Packaging Systems of Trevose, Pennsylvania. The tunnel portions 120, 122 are formed of a rugged aluminum construction and each have four energy-efficient blower systems illustrated at 124. One eighty (80) inch oven could also be used instead of two

forty (40) inch tunnel portions. Each tunnel includes opposing ends, two opposing sides 120a, 122a, and two inner walls 120b, 120b. A heating chamber 121 is formed inside each tunnel. The article passes through the chamber 121 on the conveyor without spinning. As illustrated, the tunnel portions 120, 122 are placed over top the conveyor and do not engage the conveyor.

Referring to Figure 5, illustrating an end view of die first heat mnnel portion 120 taken along line 5-5 of Figure 4, the tunnel includes an air baffle system 126 and heaters 128 for heating the air drawn in by the blowers 124. The air is forced into a manifold area 130 on the upper part of the mnnel 120 and drawn into the side plenums 132, and outward dirough an air discharge slot 136 extending longimdinally along die inner wall of the lower portion of the tunnel 120. Because the slot extends along d e longitudinal length of the tunnel and is simply a long opening and not a leister jet or fan-shaped nozzle, a less harsh blow of hot air is produced.

Typically, die tunnel portions 120, 122 each have an operating temperature of about up to 500° F. and a width adjustment for blowing air from 0 inches to 8.5 inches. They have a standard height adjustment of about 12 inches. The tunnels 120, 122 are positioned above the conveyor and supported by linear actuator stands 140 to allow a widtii adjustment of about 0 to 8.5 inches and a height adjustment of about 14 inches. Typically, the linear actuator stands 140 can be on a castor assembly include leveling pads. Thus, the tunnels 120, 122 can be positioned and tilted so tiiat the slots 136 can be positioned substantially horizontally as shown in tunnel two 122 of Figure 4 or at a gradual incline such as that shown in tunnel one 120 of Figure 4.

As shown in Figure 4, as the container progresses into tunnel one 120, the hot air forced out of the slots 136 initially engages die sector of maximum diameter 22. This heat is generated from both sides as it is blown against this sector 22, which also causes a general heat shrinking about the lower convex portion 24. As the container moves further in its travel through the heat tunnel 120, heat is progressively blown upward along the upper convex portion 122 having the greater convexity so that the container label is heat shrunk onto the

container with no creasing. This is shown by the dotted lines on the containers of Figure 4. By the time the container reaches tunnel two 122, the label has been heat shrunk onto the convex surface 14. Tunnel two 122 is oriented so tiiat the slot 136 is oriented substantially horizontal and provides blown hot air onto the general surface convex surface area 14 to ensure that the label is tightly wrapped. By the time the container exits the tunnel two, the label has been heat shrunk tightly onto die convex surface.

Naturally, if the area of greater convexity is on the lower convex portion 26, then tunnel one 120 would be inclined so tiiat the slot 136 is inclined downwardly. In some instances, the blown air produces sufficient hot air so that tunnel one may not have to be inclined at all. The generalized heat in the tunnel causes heat shrinking about the convex surface without having any label wrinkling. Additionally, it has been determined that in some instances, the mnnel can be made hot enough where bodi slots 136 can be positioned horizontal at about the level of the convex sector of maximum diameter. The overall heat generated in tiiis set-up is sufficient to cause label shrinkage without creasing and seam interruption.

It should be understood that the foregoing description of the invention is intended merely to be illustrative tiiereof, and tiiat other embodiments, modifications and equivalents may be apparent to those skilled in the art without departing from its spirit.