Glue applicator

A glue applicator for applying glue to a work sheet, such as a carton flap, by passage of the sheet between a sheet support and an applicator roller to which glue is applied, preferably with the aid of a spreading roller in peripheral contact with the applicator roller, and which rolls a thin film of the glue onto the sheet. The glue applicator is particularly adapted for use on a carton sealing machine to apply glue to one folded flap of a flattened carton structure which is thereafter fed into the machine between feed rolls of the machine which compress the carton structure to bond the glue coated flap to a second overlying flap.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to glue applicators and more particularly 
to a glue applicator for rolling a thin film of glue onto a work sheet, 
such as one folded flap of a flattened carton structure which is then fed 
into a carton sealing machine between feed rolls of the machine which 
compress the flattened carton structure to bond the glue coated flap to a 
second overlying flap. 
2. Discussion of the Prior Art 
As will appear from the ensuing description, the glue applicator of this 
invention may be used for various purposes. The applicator, however, is 
primarily intended for use on a particular type of carton sealing machine 
and will be described in this context. 
The particular sealing machine referred to is a carton taping machine 
manufactured by the General Corrugated Machinery Co., Inc., of Palisades 
Park, N.J. Since this machine is conventional and need not be fully 
explained to understand the invention, only a brief description of the 
machine will be presented. The machine is adapted to receive flattened 
carton structures each having a generally rectangular panel with a fold 
line between and parallel to two opposite edges of the panel, and flaps 
hinged to the panel along these and the other panel edges. In the 
flattened condition of the carton structure the two flaps along the two 
mentioned parallel panel edges are folded inwardly against the same side 
of the panel with the outer edge portion of one flap, referred to as the 
outer flap, overlying the other edge portion of the other flap, referred 
to as the inner flap. The remaining flaps of the carton structure are 
unfolded and lie in the plane of the panel. 
This flattened carton structure is fed edgewise into the machine between 
feed rolls which compress the structure to press its overlapping inner and 
outer flaps firmly together. As this compressed carton structure proceeds 
through the machine adhesive tapes or strips are applied to its 
overlapping flaps to firmly join the flaps after which the carton 
structure is erected to carton shape or otherwise handled. 
A variety of glue applicators have been tried on carton sealing machines of 
the kind described. However, these existing applicators are not totally 
satisfactory, at least for the particular carton sealing machine 
described, for various reasons, foremost among which are that they apply a 
bead of glue which must be spread by the pressure exerted on the carton 
flaps to be glued and hence use excessive glue which not only is 
uneconomical but also frequently results in contamination of the sealing 
machine pressure rolls and other parts and requires a long drying time for 
the bonded surfaces. This long drying time, of course, reduces the carton 
through put rate of the carton machine. 
SUMMARY OF THE INVENTION 
This invention provides a glue applicator which may be used on the carton 
taping machine discussed above, referred to herein as a carton sealing 
machine, in place of the tape applying means of the machine to effect 
adhesive bonding rather than adhesive taping of the overlapping inner and 
outer carton flaps to one another. The glue applicator has a work or 
carton support to be located in the infeed path of the flattened carton 
structure to the carton machine for entrance between the folded flaps and 
panel of the carton structure. This support supports the inner carton flap 
substantially in its folded position and supports the outer carton flap in 
a partially folded position to expose the outer edge portion of the inner 
flap normally overlapped by the outer flap. Means are provided for 
mounting the support on the carton handling machine in the infeed path of 
the flattened carton structures and spaced from the infeed rolls of the 
machine a distance such that the carton flaps may be returned to their 
folded positions during movement of the carton structure from the support 
to the infeed rolls for passage of the carton structure in its flattened 
condition between the rolls. 
Mounted on the carton support is an applicator roller whose surface may be 
pitted to provide a myriad of glue recesses and which engages the outer 
edge portion of the inner carton flap during movement of the latter across 
the support. Means are provided for applying glue to this roller as the 
inner flap passes the roller in such a way that the roller rolls a thin 
film of glue onto the flap. According to the described embodiment, the 
glue is applied to the applicator roller by a distributor roller which 
rolls against the applicator roller and which is fed with glue from a 
bottle or the like in a manner such that the distributor roller applies a 
relatively thin and even layer of glue to the applicator roller. Glue flow 
to the distributor roller is controlled by a valve actuated by each 
flattened carton structure fed to the glue applicator. After emerging from 
the applicator, the carton structure is restored to its flattened 
condition and enters the sealing machine wherein the feed rolls compress 
the structure to firmly bond the overlapping inner and outer flaps to one 
another. 
The glue applicator is adjustable to accommodate a range of flap 
thicknesses and to locate the applicator in the proper position relative 
to the carton sealing machine. As noted earlier, while the applicator is 
intended primarily for use on the described carton machine, it may be used 
for other purposes. In this regard, it will be understood that the 
applicator may be used to roll a thin layer of glue onto a variety of thin 
sheet-like work pieces, referred to herein simply as work sheets.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring first to FIG. 1, there is illustrated, in fragmentary fashion, a 
carton taping or sealing machine 10 of the kind mentioned earlier. As 
noted, this machine is conventional and its full details are not essential 
to an understanding of the invention and accordingly need not be described 
in elaborate detail. Suffice it to say that the machine has a frame 12 
mounting feed rolls 14 for feeding through the machine, in the direction 
of the arrow in FIG. 1, flattened carton structures having overlapping 
inner and outer flaps which are sealed together in the machine. One of 
these carton structures is shown at 16 in FIG. 2 in partially unfolded 
condition. 
Turning to FIG. 2, carton structure 16 comprises a corrugated cardboard 
sheet which is trimmed to the illustrated outline shape and scored along 
the illustrated broken lines to provide fold lines about which the sheet 
may be folded to erect the carton structure into a finished carton 
configuration. An initial step in this erection procedure involves folding 
of two end portions 18 and 20 of the sheet inwardly toward one another and 
downwardly against the central portion 22 of the sheet, as indicated in 
FIG. 2 by the arrows A, about fold lines 24 of the sheet. In this initial 
folded condition, the carton structure is essentially a flattened carton 
structure whose central portion 22 forms a panel and whose end portions 
18, 20 form flaps which are folded against the panel. When thus folded, 
the outer edge portion 26 of end portion or flap 20 overlies or overlaps 
the outer edge portion 28 of end portion or flap 18. For this reason, flap 
18 is referred to herein as an inner flap and flap 20 as an outer flap. 
The next step in forming the carton structure 16 into a finished carton 
configuration involves sealing or joining the flaps 18, 20 to one another 
to form essentially a flattened tubular structure. Thereafter, the carton 
structure is finally erected by folding the structure about its various 
fold lines to its finished carton configuration. The present invention is 
concerned only with joining the flaps 18, 20 and hence an elaborate 
description of the entire carton structure and its complete erection 
procedure is unnecessary. Suffice it to say that in addition to the fold 
lines 24, the carton structure has other fold lines, designated for 
simplicity by the same reference numeral 30, about which the structure is 
foldable to its final carton configuration. 
As noted, the present invention is concerned only with joining or sealing 
the flaps 18, 20 of the flattened carton structure 16. The particular 
carton sealing machine 10 illustrated is of the type discussed earlier 
which was originally designed to accomplish this flap sealing function by 
taping the flaps together. According to the present invention, as applied 
to this particular machine, the taping means (not shown) of the machine 
are removed, leaving the remainder of the machine including its feed rolls 
14, intact and the present glue applicator 32 is installed on the machine. 
As explained in more detail later, this glue applicator rolls a thin film 
of glue onto the outer edge portion 28 of the inner carton flap 18, after 
which the outer flap 20 is folded against the inner flap of the flattened 
carton structure which is fed into the machine between its feed rolls 14 
to effect adhesive bonding of the outer edge portion 26 of the outer flap 
to the adhesively coated outer edge portion 28 of the inner flap. Glue 
applicator 32 will now be described by reference to FIGS. 1 and 3-9. 
Broadly speaking, the glue applicator 32 comprises a work or carton support 
34 mounted by means 35 on the carton sealing machine 10 in the infeed path 
of the flattened carton structures 16 to the machine. This work or carton 
support has means 36 for entrance between the panel 22 and outer flap 20 
of each carton structure to partially unfold the outer flap from contact 
with the inner flap 18 and thereby expose the outer edge portion 28 of the 
inner flap, and means 38 for entrance between the panel and the inner flap 
to support the latter flap for edgewise movement along the infeed path of 
the carton structure. In the particular glue applicator shown, the carton 
support 34 is fabricated from sheet metal which is bent at right angles 
adjacent one edge to provide the sheet metal support with a relatively 
wide platen-like portion which forms the inner flap supporting means 38 
and an upstanding flange along one edge of the platen which forms the 
outer flap supporting means 36. 
Rotatably mounted on the carton support 34 to turn on an axis normal to the 
outer flap supporting flange 36 and parallel to the inner flap supporting 
platen 38 is a glue applicator roller 40. This roller overlies the platen 
38 in spaced generally parallel relation thereto for passage of the outer 
edge portion 28 of the inner carton flap 18 between the roller and platen 
with the upper surface of said edge portion in contact with the roller. 
Means 42 are provided for applying glue to this applicator roller in such 
a way that the roller rolls a thin film of glue onto the outer flap 
portion 28 during movement of the inner carton flap 18 past the roller. 
Glue flow to the applicator roller 40 is controlled by a normally closed 
shutoff valve 44 which is actuated to its open position by the inner 
carton flap as the latter approaches the roller. 
The means 42 for applying glue to the applicator roller 40 comprises a glue 
spreading roller 46 disposed in peripheral contact with the applicator 
roller. Rollers 40 and 46 are disposed within parallel, laterally 
communicating bores 48, 50, respectively, within a block 52 with a 
relatively small clearance on the order of 1/64 inch between the rollers 
and the walls of the bores. As shown in FIG. 5, the rollers have conical 
ends 54 which engage in conical bearing sockets 56 in the block 52 at the 
ends of the bores 48, 50 to rotatably support the rollers for turning on 
the axis of the bores. The rollers are disposed in peripheral contact 
through the communicating opening 58 between the bores. 
The glue applicator roller bore 48 opens through the underside of the 
roller block 52 toward the inner flap supporting platen 38. Glue 
applicator roller 40 protrudes through this open side of the bore for 
contact with the inner carton flap 18 moving past the roller, as shown in 
FIG. 6. Roller block 52 is attached at one end to the outer carton flap 
supporting flange 34 by screws 60 which pass through slots 61 in the 
flange to permit adjustment of the block and thereby the applicator roller 
40 toward and away from the platen 38 for adjusting the clearance space 
between roller and platen for accommodating a range of carton flap 
thicknesses. 
Glue applying means 42 further comprises means 62 for feeding glue to the 
spreading roller 46. This glue feeding means comprises a glue container 64 
mounted atop the sealing machine frame 12 and a tube 66 for conveying glue 
from the container to the glue feed valve 44. The particular container 
shown is a bottle with a removable cap 68 mounting a valve 70 to which the 
glue tube 66 connects. The glue bottle is mounted in an inverted position 
by engagement of its cap 68 and neck within a slot 72 in a bottle mounting 
plate 74 attached to the top of the machine frame 12. About the slot 72 is 
a projecting flange 76 which engages within a peripheral groove or recess 
78 about the bottle neck to hold the glue bottle in its inverted position, 
whereby glue gravitates from the bottle to the glue feed valve 44. The 
glue bottle 64 has a vent 80 to permit this gravitation of the glue to the 
valve. 
Glue feed valve 44 comprises a body 82 rotatably receiving a tubular valve 
spindle 84, one end of which extends beyond one end of the body. Glue tube 
66 connects to the other end of the body for feeding glue to the interior 
passage 86 through the valve spindle 84. Valve body 82 is connected to the 
glue roller block 52 by a threaded nipple 88. Extending from the valve 
spindle bore 90 in the valve body 82, through the body, the nipple 88 and 
the glue roller block 52 to the spreading roller bore 50 in the block is a 
glue passage 92. Valve spindle 84 contains a port 94 and is rotatable 
between a closed position (FIG. 7) wherein the port is blocked by the 
valve body 82 to block glue flow to the spreading roller 46 and an open 
position (FIG. 8) wherein the port registers with the passage 92 to permit 
glue flow to the roller. 
As noted earlier, the glue feed valve 44 is operable between its open and 
closed positions in response to movement of a carton structure 16 past the 
glue applicator. To this end, the extending end of the valve spindle 84 
mounts a vane 96 which projects radially of the spindle into the path of 
the inner carton flap 18 through the glue applicator. The flap supporting 
platen 38 has a clearance opening 98 for this vane. When the valve is 
closed, this vane extends across the flap path and rests against one edge 
of the clearance opening, as shown in full lines in FIG. 6. The valve 
spindle 84 is urged to this closed position by a spring 100. During its 
infeed movement through the glue applicator, the inner carton flap 18 
engages the valve vane 96 and rotates the latter and thereby the valve 
spindle to open position, shown in broken lines in FIG. 6. The spring 100 
returns the valve spindle to closed position upon disengagement of the 
carton flap from the vane. 
As noted earlier, the glue applicator is attached to the carton sealing 
machine 10 by mounting means 35. This mounting means comprises an upright 
bar 102 which is rigidly secured at its lower end by screws 104 to the 
outer side of the glue roller block 52, that is the side of this block 
opposite the carton support flange 36. Slidable on the bar 102 is a 
mounting bracket 106 having a set screw 108 for securing the bracket to 
the arm. Extending laterally of the arm is a fork 110 on the bracket 
adapted to straddle an upper plate 112 of the sealing machine frame 12 
located over the two first or infeed rolls 14 of the machine. This fork 
has set screws 114 for securing the mounting bracket 106 and hence the 
entire glue applicator, to the frame. The mounting means 35 thus permits 
vertical unitary adjustment of the carton support 34 and the glue rollers 
40, 46 relative to the sealing machine 10. 
In operation of the carton sealing machine 10 and glue applicator 32, a 
flattened carton structure 16 is fed to the machine past the applicator in 
such a way that the carton flap support flange 36 enters between the 
carton structure panel 22 and outer flap 20 to separate the latter from 
the inner flap 18 and the flap support platen 38 enters between the panel 
and the inner flap to support the latter for edgewise movement past the 
glue applicator roller 40. As the inner flap enters onto the platen, the 
flap engages the glue feed valve spindle vane 96 and rotates the valve 
spindle 84 to open position and thereby effect glue flow to the applicator 
spreading roller 46. 
During its movement past the glue applicator roller 40, the inner carton 
flap 18 engages and rotates the roller which, in turn, rotates the 
spreading roller 46. As this latter roller turns, it receives glue 
entering through the glue feed passage 92 and rolls a film or thin layer 
of glue onto the applicator roller 40. This roller, in turn, rolls a thin 
film of glue onto the outer edge portion 28 of the inner carton flap. As 
the carton structure emerges from the glue applicator, its outer flap 20 
is refolded against the inner flap and the reflattened glue coated 
structure is fed between the feed rolls 14 of the sealing machine 10. 
These rolls compress the flattened carton structure to retain its flaps 
18, 20 in firm bonding contact sufficiently long for the glue to set. The 
glued carton structure is then erected to its final carton shape, as 
explained earlier. 
In connection with the above operation, it will be understood that the glue 
applicator is located relative to the machine 10 to permit feeding of a 
carton structure 16 from the applicator to the machine in the manner 
explained. It will be understood, therefore, that the applicator carton 
support 34 is spaced sufficiently from, that is located sufficiently in 
advance of the first or infeed rolls 14 of the machine to enable folding 
of the outer carton flap 20 against the inner flap 18 prior to entrance of 
the structure between the rolls. This folding operation may be aided or 
accomplished by hand or by means on the machine, if necessary. 
A variety of applicator and spreading rollers 40, 46 may be used in the 
glue applicator. Preferably, the applicator roller is a serrated roller 
having a myriad of glue recesses or cavities in its surface and the 
spreading roller is a resilient roller in firm peripheral contact with the 
applicator roller.