Label transport vacuum drum

A cylindrical vacuum drum for carrying a label held to its surface by vacuum past an adhesive applying roll to a position where the label will touch a container and the container will be rolled along the drum surface to thereby apply the label about the container. The drum is formed of metal and is mounted for rotation about its vertical axis. The drum has a rubberlike covering thereover with at least two raised areas in the cover, which underlie the leading and trailing edge of a label that is at a greater radius than the rest of the surface. These are the areas which serve to press the label against the adhesive roll or solvent applying gravure roll. These areas have very slightly depressed zones forming slight steps just in advance thereof with a row of vacuum ports extending through the cover at the base of said steps to effectively hold the leading edge of the label down and allow the trailing edge to bend upwardly away from the outer surface of the drum. Additionally, replaceable insert strips are provided for the trailing edge of each raised pad that underlies the trailing edge of the labels so that this area which exhibits the most wear can be replaced rather than require replacing the entire drum.

BACKGROUND OF THE INVENTION 
It has been the practice, as set forth in U.S. Pat. No. 4,574,020, issued 
March 4, 1986, to receive plastic labels on the surface of a cylindrical 
vacuum drum and to carry the individual label into tangential contact with 
a gravure roll. The gravure roll is formed with finite areas which receive 
a solvent for the plastic from a fountain and the finite areas will apply 
the solvent to the foam side of a film-foam shrink label held on the drum. 
The drum is provided with pairs of raised areas which correspond to the 
leading and trailing edge of an individual label. The drum may have any 
number of such pairs of raised areas on its peripheral surface consonant 
with the label length. When the term "raised area" is used, it means that 
the radius of the drum, which is generally constant, has areas where the 
radius is slightly greater to, in effect, form pads which are vertically 
coextensive with the height of the drum but which protrude beyond the 
general surface of the drum. These pads are provided on the drum to 
correspond to the leading and trailing edges of the label. Thus susually 
different size drums are required for different lengths of labels. The 
raised areas will underlie the leading and trailing edges of the labels 
and facilitate the application of the solvent to these areas by a rotating 
gravure roll as taught in the above referred to U.S. Pat. No. 4,574,020. A 
further example of a vacuum drum is disclosed in copending U.S. patent 
application Ser. No. 831,682 filed 2-21-86 which details the system for 
applying vacuum to the vacuum posts in the drum periphery. Also, this 
copending application discloses the manner of supporting a stationary 
manifold plate in contact with the bottom of the vacuum drum in order to 
connect vacuum to the ports and also to apply air pressure and vent the 
ports in a preselected manner. 
SUMMARY OF THE INVENTION 
The present invention is an improved vacuum drum for supporting and 
transporting labels on the surface thereof with the raised pads on the 
drum periphery being further augmented with raised steps that are the 
actual underlying areas for the label leading trailing edges that receive 
the solvent from a gravure roll that engages and transfers the solvent to 
the label at the leading and trailing edges thereof. 
It is an object of the present invention to form the drum surface with an 
additional step at both the leading and trailing edge supporting pads with 
the step at the leading edge being a "down" step and the step at the 
trailing edge being an "up" step. 
Other and further objects will be apparent from the following description 
taken in conjunction with the annexed sheets of drawing.

DETAILED DESCRIPTION OF THE DRAWINGS 
With particular reference to FIG. 1, the following is a general description 
of the operation of the overall labeling system. A horizontal supporting 
table 10 of generally rectangular configuration serves to support the 
mechanisms and is itself supported above the floor by a plurality of 
vertical legs (not shown). Mounted above the table and extending generally 
across the length of the table is a conveyor generally designated 11. The 
conveyor 11 has a horizontally moving upper surface 12 which is driven in 
the direction of the arrow shown thereon. Containers or bottles B to be 
labeled are supplied at the left hand end of the conveyor 11 in an upright 
attitude on the surface 12 of the conveyor. With the conveyor surface 12 
moving in the direction of the arrow thereon, the bottles will be carried 
from the left to the right as viewed in FIG. 1. The bottles are guided by 
rails 13 which extend along either side of the conveyor 12. An overhead 
member 14 is shown which is provided in its under surface with a guiding 
slot 15 within which the finish or neck of the bottles will be guided. As 
can be seen when viewing FIG. 1, the bottles moving from the left approach 
a pair of vertically spaced, pocketed starwheels 16 and 17 which are both 
mounted to a vertical axle 18 which is rotated in a counterclockwise 
direction as viewed in FIG. 1. The starwheel 16 has 12 pockets 
circumferentially spaced about the circumference thereof which pockets are 
adapted to engage the neck of the bottles being handled and the starwheel 
17 is provided with a like number of pockets that are of somewhat larger 
dimension and are adapted to engage the sidewall of the bottles being 
handled. 
An arcuate guide 19 has a contour which is coaxial with respect to the axle 
18 and serves to hold the necks of the bottles at a precise distance from 
the axle 18 of the starwheel 16. In addition, there is a lower arcuate 
guide 20 which is mounted at a height generally the same as the height of 
the sidewall or body engaging starwheel 17 to maintain the bottles B with 
their axes vertical during the movement of the bottles by the starwheels 
16 and 17. when a bottle reaches the position generally designated P, the 
side of the bottle B will approach, generally tangentially, the 
circumferential periphery of a vacuum drum 21. The vacuum drum 21 is a 
generally cylindrical member having a height somewhat greater than the 
height of a label which is to be applied to the bottles B. The drum 21 
will have a plurality of vacuum passages opening through the surface 
thereof to, in effect, grip the individual labels supplied thereto and to 
convey the labels to the position P. The labels may be formed from a web 
22 of foam-film polystyrene which may be pre-printed and which will be 
coming from a supply (not shown) at the right through a tension takeup 
device 23. After passing the tension compensating device 23 the web 22 
will pass around a driven feed roller 24 and then to a label cutting and 
handling system generally designated 25. The label cutting device 25 cuts 
the label at a predetermined point in its length with the leading edge of 
the label being brought into peripheral engagement with the drum 21. The 
label will adhere to the outer surface of the drum 21 and move in the 
direction of the arrow on the drum 21 to carry the label past a glue or 
solvent applying station 26 where a glue roll or solvent transfer gravure 
roll 27 will apply the glue or solvent to selected, defined areas of the 
label. The gravure roll 27 is driven by a mechanism (not shown) generally 
in a counterclockwise direction, as viewed in FIG. 1, and timed to present 
the solvent to the leading and trailing edges of the label which is 
transported by the vacuum drum 21. 
At the point P the leading edge of the label will engage the sidewall of 
the bottle B and the leading edge of the label will become adhered to the 
bottle. From this point on, the bottle will be held against the surface of 
the drum by a primary backup pad 28 which is mounted to the surface of the 
table 10 by a bracket 35. The backup pad 28 may be formed of a resilient 
foam material such as foam rubber so that it will effectively hold the 
bottle B against the surface of the drum and, as the drum continues to 
rotate, the bottle will be effectively rolled along the surface of the 
label carried on the surface of the vacuum drum 21. 
As previously described, the label carried by the drum 21 will have a 
vertical, full height, line of solvent applied to the trailing edge 
thereof and the trailing edge of the label will overlap the leading edge 
and adhere thereto to form an overlap seam. The container with the label 
applied continues to be guided by the primary backup pad 28 until it 
reaches a secondary roll-on belt 29. The secondary roll-on belt 29 passes 
about a drive roll 30 which is driven in the direction of the arrow shown 
thereon. The belt 29 also passes about a relatively small diameter inlet 
roll 31. A stationary, vertical backup surface 32 maintains the belt 29 in 
a fairly straight path between the drive roll 30 and the inlet roll 31. 
The bottle B will have the label completely wrapped thereabout prior to 
the movement of the bottle into engagement with the secondary roll-on belt 
29. The primary backup pad 28 has an area 33 which tends to maintain the 
bottle in contact with the vacuum drum 21 until such time as the bottle 
engages the secondary roll-on belt 29. This provides a positive drive for 
the bottle so that when the bottle passes to the secondary roll-on belt, 
it will be rotated while moved along by the moving surface of the belt 29. 
The moving belt drives the rolling bottle so that the overlap seam of the 
label will contact a resilient pressing pad 34 which is mounted beyond the 
primary pad 28 on a bracket 35 which in turn is mounted to the table 10 as 
previously described. 
A secondary backup pad 36 is positioned in bottle engaging, diametrically 
opposed, position relative to the secondary roll-on belt 29. The pad 36 is 
also formed with a foam rubber or like resilient member mounted to a plate 
37 which in turn is mounted by bracket 38 to the top of the table 10. 
It perhaps should be pointed out also that the secondary roll-on belt 29 
and its drive roll 30 and inlet roll 31 are both mounted on a mounting 
plate 39 which may be moved relative to the upper surface of the table 10, 
and thus be adjusted toward or away from the center line of the conveyor 
12 to accommodate the mechanism for different size bottles. Likewise, the 
secondary backup pad 36 and the bracket 38 which supports it may be moved 
toward or away from the center line of the conveyor 12. 
As can be seen when viewing FIG. 1, the bottles B, after passing between 
the secondary backup pad and the secondary roll-on belt, will be held back 
by the brush spacer, generally designated 40, and that the bottles are 
moved through the brush spacer 40 in surface-to-surface contact under the 
force created by the moving belt 29, until such time as the leading bottle 
clears the spacer 40, at which time the bottle is free to move at the 
speed of the conveyor 12 into a heat shrink oven 41. The bottles will 
leave the brush spacer at regular intervals depending upon the speed with 
which the label wrap machine is operating. It should be understood that 
the drum 21 and drive roll 30 are commonly driven. 
Turning now to FIGS. 2-6, the details of the improved vacuum drum 21 of the 
invention will be described. The drum 21 is formed of a metal, such as 
"Tenzalloy", an aluminum alloy, cylindrical member 42 with a 
circumferential covering 43 of fairly hard rubber that is tightly adhered 
thereto with an interposed adhesive. The cover 43 is basically a 
continuous resilient structure formed of "Viton" Grade "B" rubber of 
DuPont Chemical Co. About the circumference of the cylindrical member 42 
at regular intervals, there are vertical passages 44 that extend the full 
height of the drum. The upper and lower ends of the passages 44 are 
plugged by threaded plugs 45. 
As can be seen when viewing FIGS. 3, 5 and 6, the passages 44 are fairly 
close to the interface of the metal member 42 and cover 43. Radially 
inwardly of the passages 44 there are parallel, vertical passages 46. The 
passages 46 have their upper ends closed by threaded plugs 47 while their 
lower ends open downwardly and communicate with vertical passages 48 in a 
bottom plate 49 closing the bottom of the member 42. The plate 49 is held 
to the drum by a plurality of allen head bolts 50 which are threaded into 
the top of the plate and pass down through countersunk holes in the member 
42. 
The plate 49 and the drum 21 are rotated as a unit by a vertical drive 
shaft 51 connected to a source of power (not shown). Each of the passages 
48 in the plate 49 is connected to a horizontal, radially inwardly, 
extending passage 52 which in turn has its inner end connected to a 
vertical passage 53 which opens through the upper surface of the bottom 
plate 49. The passages 53 communicate with a stationary vacuum manifold 
plate shown in phantom line in FIG. 3. The plate is the same as that shown 
in U.S. patent application Ser No. 831,682 filed 2-21-86. It should be 
understood that vacuum and air pressure may be fed to the passage 53 
during the appropriate intervals in the rotation of the drum 21. Each of 
the passages 46 is connected to a vertical passage 44. Each of the 
passages 44 is connected to a plurality of radial passages 55 extending 
out through the periphery of the member 42. Each of the passages 55 
communicates with one or more vacuum ports 56 that extend through the 
cover. While the drum surface, as shown in FIG. 4, has many ports 56 
distributed over its surface, there are special sets of ports provided at 
the areas of the cover which will underlie the leading and trailing edges 
of the labels. The enlarged section of FIG. 5 shows the specific 
configuration of the ports 56 and underlying vacuum passages that connect 
thereto for holding the leading edge of the label. In FIG. 5 there is a 
"raised" area or pad 57 with a step 58 down to a slightly lower part 59 of 
the pad 57. The size of the ports 56 that open into the surface 57 are 
uniform in cross-section with a set of ports 60 that are at the base of 
the step 58 on the lower level 59 of the pad 57. The labels will be held 
against and close the ports 56 when the leading edge of the label first 
engages the drum surface. However, the ports 60 which open at the base of 
the step 58 will cause the leading edge of the label to be held down 
against the step. Since the label material most commonly used is a 
film-foam plastic formed by coextrusion with the film side held in contact 
with the drum, the label will have some stiffness so that it will not 
follow the step 58 exactly but will bridge the area at the base of the 
step. In this manner the vacuum which is applied through the ports 60 will 
create a vacuum beneath the step that extends substantially the full 
height of the label and drum. The surface area that becomes vacuumized is 
many times greater at the step than at any of the individual ports 56 or 
any collective column of ports. Thus the label is firmly held at its 
forward or leading edge as shown in FIG. 5 so that when the drum carries 
the label to the position that the solvent drum 27 engages this leading 
edge, there will be absolutely no chance for the label edge to be drawn 
from the drum surface either by static charge attraction or adhesion to 
the solvent applicating drum as has been a problem in the past. This 
problem of the label leading edge coming loose from the transport drum 21 
has been a limiting factor on the speed with which the labeling system may 
be operated, and when this occurs, obviously the label will not reach the 
bottle engaging position "P" but frequently the label would become rolled 
up on the solvent drum 27 and cause a costly, time-consuming down period 
for clearing the solvent drum and resuming the startup of the system. 
Another point in the operation of the labeling system which has caused 
problems is the label trailing edge being given a full height line of 
solvent each and every time the gravure roll comes in contact with the 
trailing edge. This trailing edge must form a complete overlap seam with 
the leading edge in order to form a complete label which will pass through 
a heat shrink tunnel without having the seam open up. In order for this 
seam to be reliably made on every label, it is important that the solvent 
line on the trailing edge must be reliably made and one of the most 
important facets of the formation of this solvent line is the proper 
setting of the caliper between the label drum 21 and the solvent gravure 
roll 27. As shown specifically in FIGS. 4 and 6, the trailing edge of the 
label is held against the drum by a vertical row of vacuum ports 56 just 
in advance of a raised pad 61 on the cover 43 at the trailing edge of the 
label. In addition, a small step 62 is formed in the pad 61 and at the 
base of the step 62 a vertical series of vacuum ports 63 are located. In 
this manner, the trailing end of the label will be held in a bridging 
configuration, as illustrated in FIG. 6, over the step 62 and causing the 
trailing end of the label to actually extend away from the outermost level 
of the pad 61. In this configuration, the trailing edge portion of the 
label which is to receive the solvent will actually touch the gravure roll 
a slight moment before it will become compressed between the gravure roll 
and the pad 61. This added time helps in assuring the full line 
application of the solvent and also helps in overcoming, to a certain 
extent, any caliper adjustment problems that may be present. The caliper 
at the trailing edge pads are very critical and must be carefully 
monitored during operation. 
As could be expected, the pads 61 will become worn after prolonged use and 
normally would necessitate replacing the entire drum 21 with one with a 
new cover 43. In order to cut down on the necessary inventory of extra 
drums to be used to replace those which may become worn, and the time 
(approximately 30 minutes) that it takes to replace the entire drum, 
replacement of the trailing edges of the pads 61 may be provided. The pads 
61, which are the "high" spots on the periphery of the drum 21 at the 
trailing edge of the label and are the most critical areas on the drum, in 
so far as setting up and running the labeling machine since the trailing 
edge in all drum pads must be equidistant and any variations, if any, are 
accumulated at the lead edge. Thus, as shown in FIGS. 4 and 6, insert 
strips 64 are replaceable when the drum surface becomes worn by removing 
the socket head cap screws 65. It takes less than five minutes to replace 
the insert strips and thus the machine down time is considerably less. It 
may be seen that the areas of the drum which become the most worn are 
those corresponding to the insert strips 65 and that making these strips 
replaceable extends the life of a drum. 
With the vacuum drum, as described in detail above, the two critical areas 
of the vacuum drum, namely, the label leading edge and trailing edge, are 
provided with stepped pads and the location of vacuum ports which create a 
greater holding force than can be accomplished by merely having ports 
which open into flat areas of the drum. Further, the steps provide a means 
to emphasize the holding down force of the leading edge of the label to 
prevent solvent drum rollup of labels, and a trailing edge step that gives 
a more certain full height line of solvent applied by a gravure roll to 
the critical trailing edge of the label. Additionally, replaceable inserts 
which fit at the trailing edge of the pads on the vacuum drum serve to 
extend the life of the vacuum drum and save time over having to replace 
the entire drum when it becomes worn through extended use. 
While the foregoing sets forth the best mode contemplated by the Applicant 
for carrying out the invention, obvious modifications will be apparent 
from the description and are intended to be encompassed within the scope 
of the appended claims.