Abstract:
An apparatus and method utilize a rotatable drum implementing both an attraction mechanism and a cutter mechanism to controllably sever segments of material from a web. The drum is rotated at a rate greater than the rate at which the web of material is advanced so that the attraction mechanism supplies the sole source of tension in the web. Moreover, the cutter mechanism severs segments of material while at least a portion of the web of material engages the outer surface of the drum. In addition, an apparatus and method dynamically control the relative rates of advancement of a web of material and an outer surface of a drum such that a predetermined length of material is advanced forward of a predetermined rotational position of the drum so that the predetermined length of material is severed from the web of material while at least a portion of the web of material engages the outer surface of the drum. Moreover, an apparatus and method may utilize a carrier mechanism having at least one article carrier pivotably coupled to a rotatable hub and controlled via a camming mechanism that varies the angular velocity of the article carrier relative to that of the hub. The hub rotates about a first axis, and the pivotal coupling between the article carrier and the hub defines a second axis that is substantially parallel to and separated from the first axis. The camming mechanism is operatively coupled between the article carrier and the hub and configured to pivot the article carrier about the second axis in response to rotation of the hub about the first axis to thereby vary the angular velocity of the article carrier relative to that of the hub.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention is generally related to web registration and product handling. More particularly, the invention is generally related to registering a moving web with one or more moving products, e.g., for applying labels to containers.  
         BACKGROUND OF THE INVENTION  
         [0002]    In a great number of consumer product markets, particularly those which are low-margin and/or price-driven, an ongoing need exists for various manners of reducing product costs. For example, just-in-time manufacturing techniques, which reduce costs through minimizing inventory, have grown in prominence. In addition, improved packaging techniques and materials are constantly being developed to minimize the packaging component of product costs.  
           [0003]    Just-in-time manufacturing can place significant demands on product manufacturing and packaging equipment due to the quick turnaround that is often required to timely fill customer orders. As a result, there is an ongoing need for a manner of increasing the speed of product manufacturing and packaging equipment so that inventory costs can be reduced without adversely impacting a manufacturer&#39;s ability to fill customer orders in a timely fashion.  
           [0004]    For example, for bottled beverages such as soft drinks, beer, juice, liquor, etc., significant efforts have been expended in attempting to lower the costs associated with applying product labels to beverage containers such as glass bottles, plastic bottles, aluminum cans, and the like. A particularly cost-effective manner of labeling beverage containers utilizes a continuous web of pre-printed polymer label material that is cut into predetermined lengths, supplied with adhesive, and applied directly to the surface of a container. Adhesive costs may also be reduced by applying adhesive only to the leading and trailing edges of individual labels and wrapping the labels completely around the containers.  
           [0005]    Label machines have been developed that are capable of relatively high-speed operation, e.g., as high as 750 containers/minute or more. However, such machines have been found to be limited in several respects.  
           [0006]    One significant problem associated with such conventional labeling machines is that it is difficult to reliably control tension in a web of label material being processed at high speed. Among other concerns, a large roll of label material spun at high speed has a great deal of momentum, which often necessitates a dedicated tensioning mechanism between a supply of label material and a cutting mechanism. A tensioning mechanism, however, can introduce variable tensions at different points along the web, not to mention adding complexity and increasing the cost of the machines. Moreover, in many conventional label machine designs, separate cutting and transfer (or vacuum) drums are utilized, with the web at least partially drawn to a downstream transfer drum prior to severing a label from the web with an upstream cutting drum—an arrangement that can introduce variable tension to the web before and after cutting.  
           [0007]    As a result of these tensioning concerns, most conventional labeling machines require that a non-stretchable polymer film such as polypropylene or polystyrene be used as the web material. Stretchable polymer films such as polyethylene are often unsuitable for use with such machines because the varied tensions in the web can stretch such films lengthwise and introduce unacceptable positioning errors when cutting the web. Web material constructed from non-stretchable polypropylene or polystyrene, however, can be three or four times more expensive than a stretchable material such as polyethylene. As a result, many conventional labeling machines prohibit the ability of a producer to take advantage of the substantial savings that could otherwise be realized through the use of less expensive films.  
           [0008]    Therefore, a significant need exists in the art for an improved manner controlling tension in a web of material, particularly when supplying a web of label material in high speed labeling machines and the like. Moreover, a significant need exists for a manner of controlling web tension such that less expensive stretchable polymer films may be utilized in high speed labeling applications.  
           [0009]    The process of conveying articles such as containers past a label transport drum introduces another significant problem associated with conventional labeling machines, as well as with other machinery that utilizes multiple stations that require different transport parameters at different stations. For example, with regard to labeling machines, many conventional labeling machine designs utilize turrets or star wheels to convey individual articles past a label transfer drum at a controlled rate and with a controlled separation, or “pitch”, between sequential articles so that each article is initially presented to the transfer drum at a position thereon where a leading edge of a label is located. A turret is typically a rotatable body that includes mechanisms disposed about the periphery for gripping articles from the top and bottom ends thereof. A star wheel is typically a rotatable body that includes pockets disposed around its periphery that contact the sides of articles to advance the articles through the machine. Articles moving past a transfer drum are typically rotated as they pass the transfer drum (e.g., by virtue of contact between the drum and a fixed guide) so that labels on the drum are wrapped around the articles.  
           [0010]    Turrets typically provide the greatest degree of precision in handling and transporting articles. However, due to the additional components and coordinated movements required to bring top and/or bottom gripping mechanisms into contact with articles, turrets are relatively slow and expensive. Star wheels are typically faster and less expensive, but have the drawback that articles are not held as securely and can become misaligned within the star wheels.  
           [0011]    For example, star wheels are typically used in conjunction with a moving conveyor that supports the articles and moves at a fixed linear velocity. A label transfer drum then rotates with its outer surface traveling in the same direction as the conveyor. The velocities of the pockets in the star wheel and the outer surface of the drum are typically matched so that an article contacts a label on the drum while each is traveling at the same velocity. The articles may also be rolled or spun about its longitudinal axis to wrap the label around the article—typically by passing the article by a fixed guide or contacting the article with a relatively faster-moving belt.  
           [0012]    Given that the leading edges of successive labels are spaced apart from one another along the outer surface of the transfer drum, it is often necessary for articles to be spaced apart with the proper pitch to ensure proper alignment of articles and labels. This typically requires that the star wheel and transfer drum rotate in such a manner that the articles and labels travel faster than the conveyor. However, unless the linear velocities of the articles are identical to that of the conveyor, the articles may become tilted within the pockets of the star wheel due to friction as the articles slide along the surface of the conveyor. As a result, applied labels may have loose or bunched-up portions due to the misalignment of the articles relative to the labels.  
           [0013]    Moreover, other than when the labels are actually applied, it is often desirable to minimize the rotation of articles while disposed upon the conveyors so that the articles are conveyed in a more controlled manner. Conventional star wheels, which operate at a constant velocity, are often not capable of adequately controlling the rate of rotation of articles, which can result in label mis-registration and/or article jams at high speed.  
           [0014]    Some conventional designs also incorporate feed screws at the entry and/or discharge ends of a label application station to convey the articles in a linear direction. The feed screws may also have variable pitches to control the linear velocity of the articles, and thus the separation between articles. However, feed screws also are unable to accurately control the rotational rates of articles, and thus, label mis-registration and/or article jams still remain a significant concern.  
           [0015]    Therefore, a significant need also exists for an improved manner of conveying articles such as containers past a transfer drum in high speed applications, in particular so that the movement of such articles are carefully controlled.  
         SUMMARY OF THE INVENTION  
         [0016]    The invention addresses these and other problems associated with the prior art by providing in one aspect an apparatus and method that utilize a rotatable drum implementing both an attraction mechanism and a cutter mechanism to controllably sever segments of material from a web. The drum is rotated at a rate greater than the rate at which the web of material is advanced so that the attraction mechanism supplies the sole source of tension in the web. Moreover, the cutter mechanism severs segments of material while at least a portion of the web of material engages the outer surface of the drum. As such, the outer surface of the drum tends to slide relative to the leading edge of the web, with the attraction mechanism operating to apply a controlled pulling force thereto. Among other advantages, this permits less-expensive stretchable web material to be utilized, thereby lowering material costs. Moreover, greater reliability at high speeds is also often realized—an important consideration for many just-in-time manufacturing applications.  
           [0017]    The invention also addresses additional problems associated with the prior art by providing in another aspect an apparatus and method that dynamically control the relative rates of advancement of a web of material and an outer surface of a drum such that a predetermined length of material is advanced forward of a predetermined rotational position of the drum so that the predetermined length of material is severed from the web of material while at least a portion of the web of material engages the outer surface of the drum. The rate of advancement of the outer surface of the drum is different from that of the web of material such that relative slippage of the web of material and the outer surface of the drum is provided. As such, a web of material may be controllably severed into predetermined lengths using a relatively mechanically-simple configuration, which aids in accuracy and reliability, particularly in high speed applications.  
           [0018]    The invention further addresses additional problems associated with the prior art by providing in another aspect an apparatus and method that utilize a carrier mechanism having at least one article carrier pivotably coupled to a rotatable hub and controlled via a camming mechanism that varies the angular velocity of the article carrier relative to that of the hub. The article carrier is configured to receive and transfer an article along an article engaging surface of a fixed guide. The hub rotates about a first axis, and the pivotal coupling between the article carrier and the hub defines a second axis that is substantially parallel to and separated from the first axis. The camming mechanism is operatively coupled between the article carrier and the hub and configured to pivot the article carrier about the second axis in response to rotation of the hub about the first axis to thereby vary the angular velocity of the article carrier relative to that of the hub.  
           [0019]    Through the use of the above configuration, the carrier mechanism may be configured to match predetermined transport parameters associated with each of first and second stations that the carrier mechanism transports articles between. In one embodiment, the predetermined transport parameters may be based upon the pitch between sequential articles processed by each of the first and second stations so that the pitch of the articles transported by the carrier mechanism may be controlled to match that expected by each of the stations. In another embodiment, the predetermined transport parameters may be based upon the velocity of each article processed by the first and second stations so that the velocities of the articles transported by the carrier mechanism may be controlled to match those expected by each of the stations. As a result, greater control is provided over transported articles to permit high speed operation with greater reliability.  
           [0020]    These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the drawings, and to the accompanying descriptive matter, in which there is described exemplary embodiments of the invention.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    [0021]FIG. 1 is a top plan view of a labeling apparatus consistent with the invention.  
         [0022]    [0022]FIG. 2 is a block diagram of the primary components of the label application assembly of FIG. 1.  
         [0023]    [0023]FIG. 3 is an enlarged top plan view of the label applicator drum of FIG. 1, with portions thereof cut away.  
         [0024]    [0024]FIG. 4 is a side cross-sectional view of the label transfer drum of FIG. 3, taken along line  4 - 4 .  
         [0025]    FIGS.  5 A- 5 D are functional top plan views of the label transfer drum of FIG. 3 at different rotational positions thereof, illustrating the steps in cutting a label, applying adhesive thereto, and transferring the label to a container.  
         [0026]    [0026]FIG. 6 is a block diagram of the control system for the labeling apparatus of FIG. 1.  
         [0027]    [0027]FIG. 7 is a flowchart illustrating a dynamic web registration process for the labeling apparatus of FIG. 1.  
         [0028]    [0028]FIG. 8 is a flowchart illustrating the steps of a startup process for the labeling apparatus of FIG. 1.  
         [0029]    [0029]FIG. 9 is a timing diagram illustrating the timing of operations in the labeling apparatus of FIG. 1.  
         [0030]    [0030]FIG. 10A is a side cross-sectional view of one of the carrier mechanisms of FIG. 1, with only one article carrier illustrated for simplicity.  
         [0031]    [0031]FIG. 10B is a functional top plan view of the carrier mechanism of FIG. 10A, with only one article carrier illustrated for simplicity, and with the hub thereof removed to facilitate viewing of the camming mechanism utilized thereby.  
         [0032]    [0032]FIG. 10C is a functional side elevational view of the carrier mechanism of FIG. 10A.  
         [0033]    FIGS.  11 A- 11 E are functional top plan views of the carrier mechanism of FIGS.  10 A- 10 C at different rotational positions thereof, illustrating the transfer of articles from a conveyor to an applicator drum.  
         [0034]    [0034]FIG. 12 is a top plan view of an alternate labeling apparatus to that shown in FIG. 1, utilizing a turret article transport mechanism.  
     
    
     DETAILED DESCRIPTION  
       [0035]    Turning to the Drawings, wherein like numbers denote like parts throughout the several views, FIG. 1 illustrates a labeling apparatus  10  consistent with the principles of the invention. Apparatus  10  is principally used to apply labels in a continuous fashion to a plurality of articles  2  conveyed via an article transport mechanism (e.g., a conveyor  22 ) from an entrance end  22   a  to an exit or discharge end  22   b.  Apparatus  10  may be utilized with any number of article designs, including various containers with upright cylindrical portions, e.g., cans or bottles. The articles may be suitable for use in packaging beverages or foodstuffs, or any other type of packaged goods. For example, one suitable application of apparatus  10  is in applying labels to single-serving plastic soft drink bottles, among others.  
         [0036]    Articles  2  are conveyed past a label application assembly or mechanism  25  using a pair of carrier mechanisms  400 ,  460 , which are described in greater detail below. Carrier mechanism  400  transfers articles  2  along an arcuate guide  14  to a label application station  20  disposed opposite assembly  25 . As will be discussed in greater detail below, carrier mechanism  400  operates to vary the separation between successive articles passing through guide  14  between a first separation proximate entrance end  22   a  to a second separation proximate station  20  that is dependent upon the separation between labels provided on an applicator drum  100  in label application assembly  25 .  
         [0037]    Application station  20  includes an arcuate guide  18  against which the articles are compressed by applicator drum  100  as labels are applied to the articles. Guide  18  includes a resilient friction surface to impart a rolling action to the articles as the articles pass through the label application station such that labels are wrapped around the articles.  
         [0038]    Carrier mechanism  460  performs essentially the same operation as carrier mechanism  400  except that mechanism  460  operates to decelerate articles from a first predetermined separation that matches the separation of labels on applicator drum  100  to a second predetermined separation suitable for transport on conveyor  22 . By doing so, this arrangement imparts greater stability to discharged articles by minimizing relative movement of the articles to the conveyor at the discharge end of track  16 .  
         [0039]    Labels are supplied to applicator drum  100  from a web supply  30  supplying a web  4  of labeling material. Typically, web  4  includes a pre-printed polymer material formed of a polymer such as polyethylene. Other materials, including polymers such as polypropylene and polystyrene (among others) may also be used, although polyethylene has the additional advantage in that it is significantly less expensive than other polymers. Polyethylene film tends to be more stretchable than other polymer films. However, due to the constant tension provided in web  4  by the unique design of label application assembly  25 , the stretchability of this material does not adversely impact the quality of labels supplied by the assembly.  
         [0040]    Web supply  30  includes a pair of supply rolls  32 ,  34  that supply web  4  to a measuring roller assembly  50 . Only one of supply rolls  32 ,  34  is active at any time, and a conventional change-over mechanism (not shown) may be used to switch between the rolls with minimal down time.  
         [0041]    Measuring roller assembly  50  operates as a linear feed rate sensor using a free-wheeling roller  52  coupled to a rotational position sensor  54 . Roller  52  has a known diameter such that the linear velocity of the outer surface thereof, and thus the linear feed rate of the web, may be calculated directly from the rotational speed of the roller. Sensor  54  may be any known rotational position sensor, e.g., an optical encoder.  
         [0042]    Web  4  proceeds from assembly  50  to a web tracking control assembly  60  that is utilized to maintain lateral alignment of the web in assembly  25 . Web  4  then proceeds to a registration sensor station  70  that detects the position of registration marks disposed on the web. Station  70  includes a roller  72  and a registration sensor  74  disposed opposite roller  72  at a lateral position relative to the web to detect registration marks disposed thereon. Registration sensor  74  may be positioned at practically any point between web supply  30  and applicator drum  100  in the alternative.  
         [0043]    It should be appreciated that registration marks may take any number of forms, whether printed or otherwise formed in web  4 . Printed registration marks may be disposed outside of a visible area on the labels, or may be integrated within the design printed on a label. Moreover, registration marks may be disposed at a cutting position for a label, or may be separated therefrom by a predetermined distance. Other registration mark designs may be utilized in the alternative.  
         [0044]    From registration station  70 , web  4  proceeds to the surface of applicator drum  100 , where an attraction mechanism disposed on the outer surface of the drum applies a controlled tension to the web. Moreover, a pair of movable cutter assemblies  130 ,  170  disposed on drum  100  operate to sever labels from web  4  as each assembly  130 ,  170  passes a fixed knife  82  in a cutting station  80 . As will be discussed in greater detail below, the rate at which web  4  is supplied via web supply  30  is controlled relative to the rotation of applicator drum  100  (which is driven by a main drive motor  85 ) such that a predetermined length of the web is disposed forward of a cutter assembly  130 ,  170  as the assembly passes fixed knife  82 , whereby individual labels are severed from web  4  in a controlled manner.  
         [0045]    An adhesive station assembly  90  is disposed beyond cutting station  80  to apply adhesive to leading and trailing ends of each label using an application roller  92 . As will be discussed in greater detail below, adhesive is applied to the leading edge of the label prior to severing the label from web  4 , such that the tension within the web assists in maintaining the leading edge of the label on the outer surface of applicator drum  100  as adhesive is applied to the leading edge thereof.  
         [0046]    After adhesive is applied to the leading and trailing edges of a label, the label is presented to an article  2  via rotation of applicator drum  100 , whereby rotation of applicator drum  100  through label application station  20  wraps the label around the article as the article rolls against guide  18 .  
       Label Application Assembly  
       [0047]    [0047]FIG. 2 illustrates the primary components involved in supplying and severing labels from web  4  in a controlled manner. Assembly  25  is under the control of a control system  200 , which operates to control the supply rate of web  4  relative to the rotation of applicator drum  100 . Applicator drum  100  is rotated via a main drive motor  85  coupled to the drum via a linkage diagrammatically represented at  86 . The rate of rotation of drum  100  is measured via a rotational position sensor  88 , which may be any type of known rotational position sensor such as an optical encoder. Control system  200  also receives the output of sensor  54  to generate therefrom a measurement of the linear feed rate of web  4 . Control system  200  also receives a registration signal from registration sensor  74 .  
         [0048]    In response to these inputs, control system  200  controls a drive motor  36  to control the rate of rotation of supply roll  32 , and thus the feed rate of web  4 . Drive motor  36  is typically a servomotor, and as such, additional input is provided to control system  200  via a rotational position sensor  38  (e.g., an optical encoder) which provides feedback from drive motor  36 . It should be appreciated that a similar servomotor may also be used to drive supply roll  34  in a similar manner.  
         [0049]    Assembly  25  is thus configured in a master-slave relationship, whereby the supply rate of web  4  is controlled relative to the speed of applicator drum  100 . In the alternative, a reverse configuration may be provided wherein the rate of rotation of applicator drum  100  is controlled relative to the feed rate of web  4 . In addition, it may be desirable in some applications to control both the feed rate of web  4  and the rotational rate of applicator drum  100 . Therefore, the invention should not be limited to the configuration illustrated herein.  
         [0050]    One embodiment of the invention utilizes a servomotor with a built-in encoder such as the FSM  460  servomotor from Centurion as the drive motor  36  and rotational position sensor  38 , with an HR 625-500-x-BE1 Optical Encoder from Dynapar coupled to a 50.93 mm diameter measuring ruler used for rotational position sensor  54  and measuring roller  52 , a Model NT-6 Optical Sensor available from Sick for registration sensor  74  and an HR-625-2500-x-BE1 Optical Encoder from Dynapar used for rotational position sensor  88 . Rotational position sensor  54  may be geared with a ratio of 80/40 to measuring roller  52  to provide a resolution of 0.0393 mm/count or 25.5 counts/mm. It should be appreciated that these components are merely examples of a wide variety of other components that may be utilized in assembly  25  in the alternative.  
         [0051]    [0051]FIGS. 3 and 4 illustrate applicator drum  100  in greater detail. Applicator drum  100  includes a rotatable drum body  102  configured to rotate about a fixed shaft  120 . Rotatable body  102  includes an outer surface  104  having a plurality of vacuum ports  106  disposed thereon and supplied with a source of vacuum and/or positive pressure through a set of distribution channels  108  coupled to a vacuum port  109  (FIG. 4).  
         [0052]    Two sets of raised pads  110 ,  111  and  112 ,  113  are disposed on outer surface  104  to receive leading and trailing edges of a label as the label passes an adhesive application station so that adhesive may be applied to the opposing edges of the labels. An applicator roller (not shown in FIGS. 3 and 4) is offset from outer surface  104  such a distance that label material supported on any pad  110 - 113  will be compressed against the roller, but material disposed between the pads will not. Thus, adhesive is applied only to the material supported on a pad.  
         [0053]    As will become more apparent below, pads  110  and  111 , and pads  112  and  113  are separated from one another around the circumference of drum  100  at a distance that is greater than the length of the labels so that the leading edge of each label may have adhesive applied thereto prior to severing the label from the web. This reduces the likelihood of a label sticking to the adhesive roller due to the additional tension provided by the unsevered web.  
         [0054]    It is desirable for drum body  102  to be a changeable component such that different predetermined lengths of labels may be accommodated in apparatus  10 . Different lengths of labels are accommodated by utilizing different relative spacing between pads  110  and  111 , and between pads  112  and  113 . It may also be desirable to enable leading pads  110 ,  112  to be removed from outer surface  104  and positioned at various points thereon to support different label lengths. The separation of pads  110  and  112 , and of pads  112  and  113  will vary depending upon a number of factors, including the desired length of labels, as well as the relative positions of cutting station  80  and adhesive station assembly  90 . Determination of the desired separation for any given combination of parameters is well within the ability of one of ordinary skill in the art.  
         [0055]    As shown in FIG. 3, two sets of pads, pads  110  and  111 , and pads  112  and  113 , are provided around the circumference of rotatable body  102 , each matched with a cutter mechanism  130 ,  170 . It should be appreciated that any number of cutter mechanisms and associated raised pads may be disposed around the circumference of drum body  102  in the alternative.  
         [0056]    As best shown in FIG. 3, cutter mechanism  130  (which is configured in a similar manner to cutter mechanism  170 ) includes a rocker body  132  pivotally mounted to pivot about a shaft  134  that extends parallel to shaft  120 . A spring  136  (FIG. 4) is mounted concentrically with shaft  134  to compensate for temperature expansion in the bearing (not shown) through which the rocker body is pivotally mounted about shaft  134 . As shown in FIG. 3, at one end of body  132  is disposed a cam follower assembly  140  including a roller  142  rotatably mounted about an axle  143 . Axle  143  is secured via a bolt  144  to a follower body  145 , and a flexible boot  146  seals the assembly. Cam follower assembly  174  of cutter mechanism  170  (FIG. 4) is configured similarly to assembly  140 .  
         [0057]    Knife assembly  150  is disposed at the opposite end of rocker body  132  from cam follower assembly  140 . A knife blade  152 , having an edge  153 , is secured to the end of rocker body  152  via a bolt or other securing mechanism  154 . Edge  153  of knife blade  152  projects through an opening  114  in outer surface  104  of body  102 , immediately following trailing pad  111  around the circumference of body  102 .  
         [0058]    A spring assembly  160  including a spring  162  extends perpendicular to shaft  120  and biases cutter assembly  130  toward an extended position, with knife blade  152  projecting through opening  114  beyond outer surface  104 . A set screw  164  controls the tension of spring  162 .  
         [0059]    Roller  142  of cam follower assembly  140  rides along a cam  122  disposed on the outer surface of shaft  120 . Cam  122  is circular in cross section with the exception of a recessed portion  124 . Recessed portion  124  may have any number of profiles, e.g., a flattened profile as illustrated in FIG. 3. Recessed portion  124  is angularly oriented such that roller  142  engages the portion when knife blade  152  of knife assembly  150  is directly opposite fixed knife  82  of cutting station  80 , thereby extending the knife blade at this position to shear a label from the web.  
         [0060]    FIGS.  5 A- 5 D illustrate the steps in severing a label from web  4  and applying the label to an article  2  presented at label application station  20 . As shown in FIG. 5A, a leading edge  4   a  of web  4  is shown as fed forward of knife  152  of cutter mechanism  130  to a position where the leading edge slightly overlaps pad  110  when the pad is disposed opposite roller  92  of adhesive application assembly  90 . When in this position, drum  100  rotates so that pad  110  sweeps under roller  92 , sandwiching web  4  and applying adhesive  6  to the web proximate leading edge  4   a.  At this point, the label is still unsevered from the web, so the tension provided via the attraction mechanism generated by the vacuum ports in outer surface  104  of drum  100  assists in attracting leading edge  4   a  to the outer surface of the drum, and thus away from adhesive roller  92 . As such, this often eliminates the need for a blow off mechanism on the adhesive roller or the need for an increased level of vacuum proximate the leading edge as is required on many conventional designs.  
         [0061]    As also shown in FIG. 5A, knife blade  152  of cutter mechanism  130  is retracted as roller  142  rides along the raised portion of cam  122  on shaft  120 .  
         [0062]    Next, as shown in FIG. 5B, drum  100  has rotated to the point at which knife blade  152  is directly opposite fixed knife  82 . Web  4 , which is fed at a slower rate than the rate of rotation of drum  100 , has been fed to the desired label length such that the precise point at which the web is to be severed is located between knife blade  152  and fixed knife  82 . With roller  142  of cutter mechanism  130  contacting the recessed portion  124  of cam  122 , cutter mechanism  130  is pivoted about shaft  134  to extend knife blade  152 , and thereby provide a shearing action with fixed knife  82  to sever a label  5  from web  4 .  
         [0063]    Next, as shown in FIG. 5C, upon further rotation of drum  100 , pad  111  sweeps under adhesive roller  92  to apply adhesive  6  to the trailing edge  4   b  of label  5 . In addition, at this time an article  2  is brought into contact with leading edge  4   a  of label  5  such that the adhesive thereon adheres to article  2 . The label is pinched between article  2  and outer surface  104  and is rolled about its longitudinal axis to wrap label  5  around the article. As may also be seen from this figure, a new leading edge  7   a  is formed for web  4 .  
         [0064]    Next, as shown in FIG. 5D, label  5  has almost completely wrapped around article  2 , and will continue to do so until the adhesive  6  proximate trailing edge  4   b  of label  5  contacts the article. In addition, the new leading edge  7   a  of web  4  is at approximately the same position as leading edge  4   a  was in FIG. 5A, immediately prior to application of adhesive by virtue of roller  92  sandwiching the web against a leading pad  112 . Upon further rotation, cutter mechanism  170  will therefore sever another label from web  4 , and the process will repeat. Thus, with this configuration, drum  100  processes two labels during each full rotation of the drum. With other numbers of matched cutter mechanisms and raised pads, different numbers of labels may be handled by drum  100  in the manner described herein.  
         [0065]    Control system  200  is illustrated in greater detail in FIG. 6. The control system is primarily controlled via a CPU controller  202 , which may be, for example, a CSM/CPU 502-03-853-03 digital processor from Gidding &amp; Lewis, among others.  
         [0066]    An operator interface and controls block  204  is shown interfaced with controller  202  through a discrete input module  206 . Block  204  provides user interface for apparatus  10  with a operator, e.g., outputting status information to an operator through a video display and/or through various control panel indicators, as well as providing various operator controls, including “Start” and “Stop” buttons, “Jog” and “Auto” buttons, Label Feed “On” and “Off” Buttons and Adhesive “On” and “Off” buttons, among others.  
         [0067]    Controller  202  provides output through a discrete output module  208  to generate a digital signal speed control to a main drive frequency control block  210  that controls the main drive motor  85  to operate in “fast” or “slow” modes. Block  210  receives a signal from a potentiometer  211  that controls the overall speed of the main drive, and is used by an operator to match the running speed of assembly  25  to the supply of articles. Moreover, block  210  outputs a control signal to analog speed signal control block  212  for controlling the speed of a conveyor motor  214  coupled to conveyor  22  (FIG. 1).  
         [0068]    Controller  202  also interfaces with the various sensors utilized to provide web registration via an I/O module  216 . Specifically, module  216  provides an interface between controller  202  and each of servo amplifier  42 , encoders  54 ,  88  and registration sensor  74 . Servo amplifier  42  is coupled to servo motor  36  and its associated encoder  38  (not shown in FIG. 6). Also shown is the servo amplifier&#39;s connection to a second servo motor  40  which drives a web supply roll  34  in a similar manner to servo motor  36 . It should be appreciated that only one of motors  36 ,  40  is driven at a time based upon which supply roller is being run through assembly  25 .  
         [0069]    Module  216  also provides an interface with controller  202  to a vacuum drive frequency control block  218  that drives a vacuum motor  220 . It is through this arrangement that the level of vacuum (or attraction) supplied to the outer surface of applicator drum  100  is controlled.  
         [0070]    Blocks  210 ,  212  and  218  are all coupled to a main power source  222 . Power is also supplied via block  222  to an oil pump motor  224 , a turret up/down motor  226  (if so equipped) and a transformer  228 . Transformer  228  provides the power signals for a bus  203  coupled between controller  202 , servo amplifier  42 , a power supply  230 , web tracking control station  60 , adhesive applicator  90  and an air conditioner/heat exchanger block  232 . Power supply  230  provides power to operator interface and machine controls block  204  and input module  206 . Web tracking control station  60  receives input from a web guide sensor  62  and outputs control signals to an actuator  64  to provide lateral alignment of the web, in a manner generally understood in the art. Adhesive applicator  90  provides control signals to a bar heater  94  and base heater  96 , which respectively heat applicator roller  92  and a tank in applicator  90 . These latter components are used in a number of conventional labeling apparatus designs, and will not be discussed in greater detail herein.  
         [0071]    [0071]FIG. 7 illustrates a closed loop control algorithm  250  utilized in controller  202  to control servo motor  36  to provide web registration consistent with the invention.  
         [0072]    Algorithm  250  utilizes a plurality of computational blocks  252 ,  254 ,  256 ,  258 ,  260 ,  262  and  264  to drive a control signal to servo amplifier  42  to operate servo motor  36 . Blocks  252 - 256  are clocked by the leading edge of the output of registration sensor  74 , while blocks  258 ,  260 ,  262  and  264  are clocked by a clock signal represented at  266 , e.g., a 2 kHz clock signal.  
         [0073]    Control algorithm  250  attempts to maintain a ratio of pulses between drum positioning encoder  88  and linear feed rate encoder  54  (designated E 1  and E 2 ) according to the equation: 
           R   0   =L   0 /(π D ( E   2   0   /E   1   0 ) 
         [0074]    where R 0  is the nominal ratio, L 0  is the nominal label length, D is the diameter of free wheeling roller  52 , and E 1   0  and E 2   0  are the total numbers of pulses, respectively, for full revolutions of encoders  88  and  54 .  
         [0075]    For each label n, block  252  receives the pulse train outputs (designated E 1  and E 2 ) of drum positioning encoder  88  and linear feed rate encoder  54  to generate a registration error signal E that is the difference, expressed in pulses, between the position of the registration mark on the label sensed by the registration sensor  74  and the preset (or expected) position of the mark.  
         [0076]    Block  254  calculates the length of a label n from registration mark to registration mark in pulses of the linear feed rate encoder  54  (designated E 2   n ). This information is utilized in block  256  to calculate a ratio between encoders  88  and  54  for the next label (n+1) that is corrected for the registration error E, using the equation: 
           R   (n+1) =( E   2   n   ±E )/ E   1   0   
         [0077]    Block  258  calculates the actual ratio R a  of the number of pulses of each of encoders  88  and  54  between time marks using the actual pulse trains from encoders  88  and  54 , i.e.: 
         
       R 
       a 
       =ΔE 
       2 
       /ΔE 
       1 
     
         [0078]    Block  250  calculates a ratio error E r  that is the difference between the current ratio R n  (i.e. E 2   n /E 1   0 ), and the actual ratio R a , using the equation: 
         
       E 
       r 
       =R 
       n 
       −R 
       a 
     
         [0079]    In addition, a command for the servo motor such to achieve the actual ratio in the next time interval is calculated, using the equation: 
         
       R=R 
       a 
       ±E 
       r 
     
         [0080]    Next, block  62  generates from the command from block  260  the proportional and integrated feedback signals for controlling servo motor  36 . This information is summed with the derivative gain feedback generated by block  264  based upon the feedback signal from servo motor encoder  38  (designated E 3 ). It should be appreciated that simultaneous use of integrated, derivative and proportional feedback signals is well known in the art. Moreover, it should be appreciated that other control algorithms which utilize the aforementioned equations may also be used in the alternative.  
         [0081]    A self-teaching start-up routine  280 , executed by controller  202  of control system  200  to initialize apparatus  10 , is illustrated in greater detail in FIG. 8. Routine  280  configures apparatus  10  to operate with a new roll of web material using a self-teaching process that often eliminates the requirement in many applications for the label length to be manually input by an operator. Routine  280  is executed by an operator after the operator installs a new web roll and feeds the leading edge of the web into assembly  25 . The routine begins in block  284  by advancing the web (e.g., in response to user input received from an operator through controls  204 ) through assembly  25  until the registration sensor is in front of the first registration mark on web. At this time, the operator hits a “Stop” button to manually halt the apparatus. Next, in block  286 , the web is advanced (e.g., in response to user input such as an operator depressing a “Start” or “Jog” button) until the registration sensor is proximate the next mark on the web. Then, the operator again hits the “Stop” button to halt the apparatus. During blocks  284  and  286 , the output of the registration sensor and linear feed rate encoder are monitored to determine the number of pulses between the marks, and thus, the nominal length of the label (L 0 ) in terms of the output of the linear feed rate encoder.  
         [0082]    Next, in block  288 , the web is advanced in response to user input from an operator; however, in this block, the controller automatically advances the web and attempts to stop the web precisely at the next registration mark without any additional operator intervention. At this time, the operator may also be requested to indicate to the system whether the automatic advance successfully terminated directly at the next registration mark.  
         [0083]    Assuming that this operation was successful, in block  290  the controller receives user input from an operator to manually rewind and/or advance the web to the desired cut position for the label (e.g., in response to an operator depressing suitable “Rewind” and “Advance” buttons). Next, the operator depresses a button or otherwise indicates to the controller that the cut position has been set. During the manual rewind/advance, the controller monitors the linear feed rate encoder output to set the cut position in units of the linear feed rate encoder pulses relative to the registration mark.  
         [0084]    Next, in block  292 , the controller attempts to operate the apparatus to cut the first label based upon the registration information calculated above for the web, e.g., in response to suitable user input from an operator. The controller halts the apparatus after the first label is cut, and in block  294 , waits to receive acknowledgment from the operator that the label cut was acceptable. If not successful, a process similar to block  284 - 292  may be repeated, or the routine may terminate with a failure indicated. However, if successful, the controller stores the program in one of a plurality of program storage locations. After the program is stored, the apparatus is then ready to begin processing articles using the aforementioned closed loop control algorithm when suitable user input is received from an operator.  
         [0085]    The sequence of logic signals in apparatus  10  is illustrated at  300  in FIG. 9, where each signal, timed according to the rotational position of the drum (i.e., from 0 to 360 degrees, with each complete rotation, or cycle, being designated A-D). A container detector signal  320  is shown being latched to “on” upon receipt of a each container into apparatus  10 .  
         [0086]    For example, during initiation of a label feed operation during a cycle A, a label feed logic signal  310  may be enabled, typically in response to an operator depressing an label feed “On” button on the apparatus, or in response to a signal provided by an external device such as a sensor that detects when one or more containers or articles are about to be received in the apparatus for labeling. Upon container detector signal  320  being latched to “on”, an internal label feed logic latch signal  330  then latches prior to the start of cycle B, so that it is effectively delayed one cycle from the label feed logic signal. Then, after the knife has passed the cutting position (the 0 degree position) at the start of cycle B, a servomotor command signal  330  is asserted to start drive motor  36 . The speed profile of drive motor  36  is illustrated at  360 , including a minimal possible acceleration phase  362  that is encountered from about 15 to about 115 degrees, a minimal overspeed necessary phase  364  from about 115 to about 270 degrees, a deceleration to nominal speed phase  365  from about 270 to about 285 degrees and a nominal speed phase  366  thereafter that is related to a machine speed of V n =CPM (containers per minute)×L (label length).  
         [0087]    [0087]FIG. 9 also illustrates a adhesive roller logic signal  370  that is initially illustrated as enabled to reflect that adhesive should be applied to any labels processed by apparatus  10 . If adhesive application is enabled, immediately after the servomotor command signal  340  is asserted, an adhesive roller logic signal  380  is applied, and an adhesive roller solenoid (represented by signal  390 ) is asserted about 90 degrees delayed relative to signal  380  (so that adhesive may be applied to the last label whenever a labeling is stopped, as described below).  
         [0088]    Assuming now, for example, that label feed logic signal  310  is disabled during cycle A. With the label feed logic signal  330  delayed one cycle relative to signal  310 , signal  330  is not unlatched until just prior to the completion of cycle B. Then in cycle C, the speed profile  360  of drive motor  36  is altered to perform a stop down, including a minimal deceleration phase  367  from about 90 degrees to about 120 degrees and a rewind phase  368  that serves to withdraw the web a predetermined distance (e.g., about 2-3 mm behind the knife blade) and thus maintain the web in a ready state just beyond the still-rotating drum. After a rewind, the servomotor command signal  340  is shut off, and the drive motor speed goes to null in phase  369 .  
         [0089]    Also during cycle B, once label feel logic signal  330  is unlatched, adhesive roller logic signal  380  is unlatched to inhibit adhesive application, resulting in (after a delay of about 120 degrees to permit adhesive to be applied to the last label) the adhesive roller solenoid signal  390  being deasserted.  
         [0090]    [0090]FIG. 9 additionally illustrates a restart of label application in cycle D, upon label feed logic signal  310  being enabled during cycle C. In this instance, label feed logic signal  330  is asserted just prior to the start of cycle D, and servomotor command signal  340  is applied to start drive motor  36  and cause the drive motor to follow the speed profile illustrated at  360 . However, in this cycle, the adhesive roller logic signal  370  has been disabled, so regardless of whether the internal roller logic signal  380  being set to “on”, solenoid signal  390  is not asserted, and no adhesive is applied to a label.  
         [0091]    It should be appreciated that development of suitable control programs to implement the functionality described herein, and in particular in connection with FIGS.  7 - 9 , is well within the abilities of one of ordinary skill in the art. Therefore, no additional discussion thereof is provided herein.  
       Carrier Mechanisms  
       [0092]    [0092]FIGS. 10A and 10B illustrate carrier mechanism  400  in greater detail. It should be appreciated that carrier mechanism  460  may be similarly configured, albeit with a different cam profile suitable for its function, as will become more apparent below.  
         [0093]    In general, each carrier mechanism is configured to sequentially transport articles such as a beverage containers along an article engaging surface of a guide and between first and second stations, while varying a predetermined transport parameter for the articles. In the embodiment described herein, the predetermined transport parameter is the pitch of the articles—that is, the separation between successive articles. The articles are carried by article carriers disposed at the ends of arms that are pivotably coupled to a central, rotating hub. A pitch varying mechanism utilized by each carrier mechanism relies on a camming action to rotate the arms relative to the rotating hub, whereby the pitch between transported articles may be controlled principally through rotary motion to provide reliable high speed operation for high throughput machines.  
         [0094]    The first and second pitches may each be dependent upon a number of factors, e.g., the linear and/or rotational velocity of articles, the size of the articles, etc. As such, the parameters of the surrounding stations that may need to be matched to provide controlled pitch with a carrier mechanism may not be cast in terms of separation, but may instead be based upon velocity or another parameter, as will become more apparent below. However, given that pitch, velocity, article size, etc. are interrelated with one another, it will be appreciated that a carrier mechanism consistent with the invention may alternatively be configured to control other parameters.  
         [0095]    As shown in FIG. 10A, carrier mechanism  400  includes a shaft housing  402  having a drive shaft  404  rotatably mounted therein via bearings  406 . A cam housing  408  is fixedly coupled to shaft housing  402 , and a hub  409  is fixedly coupled to drive shaft  404  to cooperatively rotate therewith.  
         [0096]    As shown in FIG. 11 a,  for example, a set of five article carriers  410   a,    410   b,    410   c,    410   d  and  410   e  are evenly spaced around hub  409  in the illustrated embodiment. Only one such article carrier  410   a  is shown in FIGS. 10A and 10B to simplify the illustrations. However, it should be appreciated that any number of article carriers may be utilized on carrier mechanism  400  consistent with the invention.  
         [0097]    Article carrier  410   a  includes upper and lower arms  412 ,  414  that respectively terminate with a gripping mechanism such as a pair of pockets  413 ,  415  integrally formed thereon for receiving an article  2  supported on conveyor  22 . Pockets  413 ,  415  are sized and configured to circumscribe a cylindrical portion of article  2 , and may utilize different profiles for other article configurations in the alternative. Moreover, other gripping mechanisms may be utilized as an alternative to pockets  413 ,  415  depending upon the type of article being transported. Moreover, in other embodiments, multiple axially-displaced pockets may not be required to reliably engage articles.  
         [0098]    As best shown in FIG. 10A, arms  412 ,  414  are fixedly mounted on a rocker shaft  420  that is pivotably coupled to hub  409  through bearings  422 . Rocker shaft  420  projects through apertures in a phaseable lid  425  and a seal lid  426  that overlap hub  409  and seal the inner components thereof.  
         [0099]    A linkage member  428  is fixedly mounted at the lower end of rocker shaft  420 , with a cam follower  429  disposed at a distal end thereof. In the illustrated embodiment, cam follower  429  is configured as a roller that engages an inwardly-facing wall  442  in cam housing  408  that functions as a cam for carrier mechanism  400 .  
         [0100]    As best shown in FIG. 10B, cam follower  429  and linkage member  428  are circumferentially spaced about rocker shaft  420  from arms  412 ,  414  to form an acute angle α relative thereto. In the illustrated embodiment, α is approximately 60 degrees, although other angles may be used in the alternative.  
         [0101]    In addition, as best shown in FIG. 10C, it may be desirable to provide an angular offset between arms  412 ,  414  about rocker shaft  420  so that arm  412  slightly leads or trails arm  414  and thereby induces a controlled tilt to an article  2  engaged by pockets  413 ,  415 . By doing so, improved label alignment, and a reduced likelihood of label misalignment, may result due to the ability to compensate for any imperfections in the containers and/or machined parts that might otherwise induce improper tilting of containers carried by the mechanism. In the illustrated embodiment, the angular offset is provided by manipulation of phaseable lid  425  (FIG. 10A), which is configured to be secured at different angular positions within a defined range to vary the angular offset between arms  412  and  414 . Moreover, the angular offset of arms  412 ,  414  is typically set to impart a tilt to an article retained thereby to an angle β offset from vertical of about +/−1 degree (the amount of tilt is exaggerated in FIG. 10C for illustrative purposes). Other degrees of tilt may be utilized in other embodiments, and may often be determined empirically based upon factors such as the type and configuration of the articles, among other factors.  
         [0102]    Returning to FIG. 10A, hub  409  is considered to rotate about a first axis  451  defined along the longitudinal axis of drive shaft  404 , while article carrier  410  is considered to pivot about a second axis  452  defined along the longitudinal axis of rocker shaft  420 . In operation, therefore, as hub  409  rotates about first axis  451  in response to rotation of drive shaft  404 , cam follower  429  rides along cam  442  to controllably pivot article carrier  410   a  about second axis  452 . As a result, the angular velocity of article carrier  410   a  is controllably varied relative to the angular velocity of hub  409 . It should be appreciated that a multitude of other known cam and linkage arrangements may be utilized in the alternative to impart a controlled angular offset of each article carrier relative to hub  409 .  
         [0103]    The profile of cam  442  is selected to provide a controlled pitch at first and second positions of carrier mechanism  400 . For example, as shown in FIG. 11A, the first position is the position at which an article carrier (e.g., article carrier  410   b ) engages an article (e.g., article  2   b ) on conveyor  22 . The second position is the position at which an article carrier (e.g., article carrier  410   a ) deposits an article (e.g., article  2   a ) against the outer surface of applicator drum  100 . The pitch in this application is defined as the distance between center points of successive articles.  
         [0104]    At the first position, the desired pitch is based upon the separation between articles supplied to apparatus  10  via conveyor  22 . To assure a continual supply of articles, the articles are typically permitted to “queue up” on the conveyor in an abutting relationship. As such, the separation between articles is directly related to the size of each article. With each article being cylindrical in shape, the separation between articles is the sum of the radii of successive articles. In addition, assuming each article has the same radius, the separation may be expressed in terms of twice the radius of an article, which is equal to the diameter of the article, designated herein as D A . Thus, the desired pitch at the first position, S 1 , is therefore: 
         S 1 =D A . 
         [0105]    At the second position, the desired pitch is equal to the separation between the leading edges of labels supplied on the outer surface of applicator drum  100 . Assuming an applicator drum that provides n labels evenly spaced about the drum&#39;s outer surface, the separation at the second position, S 2 , would thus be equal to the circumference of the drum (which is equal to π times the diameter of the drum, D D ) divided by the number of labels n, or: 
           S   2 =(π× D   D )/ n   
         [0106]    Thus, for an applicator drum that supplies two labels per rotation thereof, the desired pitch at the second position is: 
           S   2 =π2× D   D . 
         [0107]    To achieve the desired separations at the first and second positions, it may also be desirable to configure the cam profile based upon the desired angular velocity of the article carriers relative to the processing rate of apparatus  10 . For example, at the first position, it is typically desirable to match the angular velocity of the article carriers with the speed of incoming articles supplied to carrier mechanism to prevent line vibration and its associated problems. Moreover, to achieve the desired separation at the second position, the angular velocity is typically related to the angular velocity of the applicator drum. It should be appreciated that calculation of the desired angular velocity profile for the article carriers based upon the desired separations is well within the abilities of one of ordinary skill in the art.  
         [0108]    With carrier mechanism  400  utilizing five article carriers  410   a - 410   e,  and with applicator drum  100  applying two labels per rotation, the hub of carrier mechanism  400  is coupled to applicator drum  100  and drive motor  85  to provide a 1:2.5 gearing ratio between mechanism  400  and applicator drum  100 , whereby applicator drum  100  rotates five times for every two rotations of mechanism  400 .  
         [0109]    Also, as shown in FIG. 10B, for example, the cam profile of cam  442  defines two regions segregated at points A and B. The first region, extending counter-clockwise from point A to point B, has a fixed radius r 1  that maintains a constant angular velocity for each article carrier having its associated cam follower  429  disposed therein. Coupled with the fixed gearing ratio between the carrier mechanism and the applicator drum, the desired pitch at the second position is assured.  
         [0110]    In the second region extending counter-clockwise from point B to point A, however, an article carrier is controllably decelerated to reduce the pitch of an article carrier proximate the first position to match that of the incoming articles, then accelerated to return to the pitch of the article carrier to match that of the labels on the applicator drum. The point in which the cam profile switches from decelerating the article carrier to accelerating the article carrier is labeled as point C, and is typically disposed at an angular position that orients the article carrier at the first position (offset an angle α from cam follower  429 ). The cam profile therefore may decrease from point B to a minimum radius r 2  proximate point C, and then increase back to radius r 1  proximate point A.  
         [0111]    Typically, the variations in the cam profile form smooth transitions to facilitate rapid movement of the cam followers along the cam. It should be appreciated that the design of a cam profile that meets the above constraints is well within the abilities of one of ordinary skill in the art, and may, if desired, be determined in whole or in part empirically. Moreover, any number of alternate profiles that provide the required pitches at the first and second positions may also be used consistent with the invention.  
         [0112]    It should be appreciated that for carrier mechanism  460  (FIG. 1), which operates to transport articles from applicator drum to conveyor  22  at the discharge end  22   b  of labeling apparatus  10 , an essentially complementary cam profile may be used, which transports articles from a first position that matches the separation of articles being discharged by applicator drum  100  (essentially the same separation as the second position for carrier mechanism  400 ) to a second position that matches the desired separation of articles discharged onto the conveyor (essentially the same separation as the first position for carrier mechanism  400 ). For carrier mechanism  460 , it is desirable to return articles onto conveyor  22  at the same linear velocity as that of the conveyor to prevent any slippage or possible tilting of the articles as they are received onto the conveyor.  
         [0113]    Returning to FIG. 1, it is important to note that in the illustrated embodiment, each article carrier is configured to transport an article along an article engaging surface defined by fixed guide  14 , with the pocket disposed at the end of the article carrier merely operating to “push” the article along the guide. In many embodiments, for example, it may be desirable to abut or engage articles without actually gripping the articles (e.g., applying a compressive force to opposing sides of the articles or otherwise restraining the articles from motion in all directions). Instead, articles may effectively be trapped between the pockets and the guide so that the articles tend to “ride” along the guide under a motive force applied by the pockets—that is, the guide principally determines the path of travel for the articles, while the pockets simply accelerate and/or decelerate the articles as they travel along the guide. In different applications, it may be desirable to permit the articles to either roll or slide along the guide in a controlled manner (e.g., by selecting a material for the article engagement surface having appropriate frictional properties).  
         [0114]    By cooperatively transporting the articles using the guide to determine the path of travel, the need for movable gripping mechanisms is often eliminated. As such, complexity may be reduced, often reducing cost and improving reliability. Moreover, higher speed operation is typically possible since the additional components, movement and coordination that would otherwise be required to ensure that articles are securely gripped and released at appropriate times would likely limit the overall maximum operational speed of a gripping-type article carrier.  
         [0115]    Returning to FIGS.  11 A- 11 E, the sequence of transport for a plurality of articles  2   a,    2   b,    2   c,    2   d,  and  2   e  is illustrated. As shown in FIG. 11A, article  2   a  is being discharged onto the surface of applicator drum  100  by article carrier  410   a,  with articles  2   b,    2   c  and  2   d  queued up on conveyor  22  waiting to be transported to drum  100 . Article carrier  410   b  has engaged article  2   b,  with article carrier  410   c  beginning to be decelerated via the cam profile to match the linear velocity thereof with that of article  2   c.  Next, as shown in FIGS. 11B, 11C and  11 D, article carrier  410   b  is accelerated by the cam profile to increase the separation between article  2   b  and the following article  2   c,  while article carrier  410   c  continues to be decelerated to match the linear velocity with that of article  2   c.  Finally, in FIG. 11E, article carrier  410   b  has reached the second position, whereby the article carrier engages article  2   b  against a label disposed on the outer surface of applicator drum  100  with the desired pitch and in proper alignment with the label. Moreover, article carrier  410   c  engages article  2   c  in the first position in the same manner as described above for article carrier  410   b  and article  2   b  in FIG. 11A. Continued rotation of carrier mechanism  400  results in the same sequential controlled deceleration and acceleration of each article carrier  410   a - 410   e  so that articles are continuously transferred to applicator drum  100  with the requisite pitch therebetween.  
         [0116]    It will be appreciated that carrier mechanism  460  operates in a complementary manner to transport articles from applicator drum  100  and back onto conveyor  22 . Moreover, it should be appreciated that various modifications may be made to either of carrier mechanisms  400 ,  460  consistent with the invention.  
       Alternate Embodiments  
       [0117]    It will be appreciated by one skilled in the art that the label application assemblies and carrier mechanisms described herein may be utilized independently of one another. For example, as shown in FIG. 12, a labeling apparatus  500  may include a label application assembly  25 ′ which includes a web supply  30 ′, measuring roller assembly  50 ′, web tracking control assembly  60 ′, registration sensor station  70 ′, cutting station  80 ′, adhesive station assembly  90 ′ and applicator drum  100 ′. Each component in label application assembly  25 ′ may be configured similarly to the corresponding unprimed components in label application assembly  25  of labeling apparatus  10  of FIG. 1, or may include any of the alternatives described above for any of such components.  
         [0118]    Apparatus  500 , however, includes an alternate article transport assembly to the arrangement of carrier mechanisms and conveyor for apparatus  10  of FIG. 1. Specifically, apparatus  500  includes a conveyor  502  that transports articles to and from apparatus  500 . Articles  2  are received from conveyor  502  using a feed screw  510  that provides a controlled separation between articles. A first star wheel  520  transfers articles from feed screw  510  to a turret  540 . Articles are then presented by turret  540  to drum  100 ′ of assembly  25 ′ for application of labels to the articles. Upon further rotation of turret  540 , the articles are then transferred to a second star wheel  530 , and then to conveyor  502  for transport out of apparatus  500 .  
         [0119]    It should be appreciated that the use and configuration of feed screws, star wheels and turrets are in general well known in the art. It should further be appreciated that other article transport assemblies may be used in the alternative, e.g., various other arrangements of feed screws, turrets and/or star wheels, among others.  
         [0120]    It should further be appreciated that the carrier mechanisms described herein may be used independently of a labeling apparatus to transfer articles. In the packaging and/or bottling fields, for example, such mechanisms may be used to transport articles such as containers with a controlled pitch therebetween in various applications such as bottling machines, filling machines, cleaning machines, packing machines, etc. Moreover, in other fields, the carrier mechanisms may be used in other applications to provide controlled pitch between articles transported thereby. Also, as discussed above, the parameter controlled by a carrier mechanism consistent with the invention may be another transfer characteristic related to pitch such as velocity. This would permit, for example, a carrier mechanism to be used to transfer articles from a first station that outputs the articles at a first velocity to a second station that receives the articles at a second velocity, among other applications. Therefore, the invention should not be limited to any particular field or application of the carrier mechanisms described herein.  
         [0121]    Various additional modifications may be made to the illustrated embodiments without departing from the spirit and scope of the invention. Therefore, the invention lies in the claims hereinafter appended.