U.S. patent number 3,768,439 [Application Number 05/116,991] was granted by the patent office on 1973-10-30 for adhesive applicator.
This patent grant is currently assigned to Addressograph-Multigraph Corporation. Invention is credited to Roy C. Schweitzer.
United States Patent |
3,768,439 |
Schweitzer |
October 30, 1973 |
ADHESIVE APPLICATOR
Abstract
A method and apparatus for applying adhesive to labels wherein a
metered discrete amount of adhesive is ejected in an area related
pattern onto the rear of a label from a nozzle assembly responsive
to the position of the label on a delivery device.
Inventors: |
Schweitzer; Roy C. (Richmond
Heights, OH) |
Assignee: |
Addressograph-Multigraph
Corporation (Cleveland, OH)
|
Family
ID: |
22370444 |
Appl.
No.: |
05/116,991 |
Filed: |
February 19, 1971 |
Current U.S.
Class: |
118/315; 118/313;
118/411; 118/679 |
Current CPC
Class: |
B65C
9/2217 (20130101) |
Current International
Class: |
B65C
9/22 (20060101); B65C 9/00 (20060101); B05c
011/00 () |
Field of
Search: |
;118/411,313,243,2,7,8,3.5 ;239/87,88,95,99,119 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,071,722 |
|
Dec 1959 |
|
DT |
|
925,883 |
|
May 1963 |
|
GB |
|
Primary Examiner: Stein; Mervin
Assistant Examiner: Millstein; Leo
Claims
I claim:
1. A system for selectively applying a fluid to a relatively moving
workpiece surface, comprising in combination, structure forming at
least one nozzle orifice mounted adjacent the path of the work
surface for projecting pressurized fluid thereon;
a pump including a chamber and a fluid compression member movable
in said chamber, said nozzle being a passageway through said fluid
compression member;
transport means to carry a workpiece in a work path adjacent said
nozzle, said transport means including an actuator means;
said actuator means being in the form of a cam having more than one
major peak portion for fluid ejection pattern control, and said
responsive means being a cam follower;
a responsive means associated with said fluid compression member
and responsive to contact by said actuator means for driving said
fluid compression member in a fluid compression stroke;
whereby, fluid is ejected through said nozzle as a physical pumping
action of the transport means moving past said nozzle.
2. A system for selectively applying a fluid to a surface of
relatively moving workpiece comprising:
at least one nozzle orifice;
pump means for supplying fluid under pressure to said nozzle
orifice, said pump means comprising a chamber for receiving the
fluid, piston means movable within said chamber from a first
position of increased chamber volume to a second position of
decreased chamber volume for pressurizing and forcing the fluid
from said chamber through said nozzle orifice;
first conduit means providing fluid communication between said
chamber and said nozzle orifice;
second conduit means providing fluid communication between said
chamber and a source of fluid;
valve means disposed within said second conduit means and operative
to permit fluid movement only in the direction from said source of
fluid to said chamber, third conduit means providing communication
between said chamber and said source of fluid, normally closed
valve means disposed within said third conduit means, and detector
means responsive to the absence of a workpiece on said carrier
means and operative to open said normally closed valve means
whereby fluid is recycled to said source of fluid rather than
forced through said nozzle orifice;
valve means disposed within said first conduit means comprising a
valve body and seat coacting to permit fluid movement only in the
direction from said chamber to said nozzle orifice, said valve
means opening in response to movement of said piston means from
said first position to said second position;
carrier means for supporting and moving a workpiece into the path
taken by fluid issuing from said nozzle orifice; and
means mounted for movement with said carrier means to move said
piston means in timed sequence with the movement of said workpiece
into a fluid-receiving position with respect to said nozzle
orifice.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to a method and apparatus for
applying adhesive and more particularly to the application of
adhesive in measured discrete amounts to a label prior to the label
being applied to a magazine, envelope, or the like.
There have been several prior art proposals for machines which
apply labels to magazines, envelopes, or other mailing pieces in a
continuous relatively high speed operation. Basically these devices
use computer output which produces columns of names and addresses
and other pertinent information on paper stock. The stock is then
cut to the desired label size. Adhesive is applied to the back side
of the label, and the label is then applied to the magazine,
envelope, or other mailing piece.
Conventionally the prior art devices have utilized glue fountains
and rollers for the application of adhesive to the labels.
Essentially the label is moved past the roller with the underside
thereof being brought into contact with the adhesive on the
roller.
This technique of applying glue to the labels by means of a glue
fountain has several serious drawbacks. First, it is difficult to
apply a measured metered amount to each label. This raises the
possibility of either an insufficient amount of adhesive being
applied, resulting in an improperly adhering label, or of too much
glue being applied resulting in the glue being squeezed from
underneath the label onto the surface of the mailing piece where it
can cause other pieces to stick thereto. Also, with the glue
fountain technique of applying adhesive, there is a propensity for
the glue to become smeared on the surface of the device which is
transporting the label, thus causing subsequent labels to stick to
this extraneous adhesive and not be properly applied to the mailing
piece.
These, and other drawbacks in the glue fountain technique, such as
the tendency of the glue to crust over in the atmosphere, presented
certain deficiencies in this type of labeling machine.
SUMMARY OF THE INVENTION
According to the present invention, an adhesive applying device for
use in a labeling machine is provided which ejects a discrete
stream of adhesive in an area related pattern against the backside
of a label, responsive to the label occupying a given position as
it is being transported past the device. Also, preferably, the
device includes means to prevent the ejection of the stream in the
absence of a label occupying a preselected position.
These and other advantages will become apparent together with a
fuller understanding of the invention by reference to the following
description and accompanying drawings.
IN THE DRAWINGS
FIG. 1 is a plan view of an adhesive applying device, according to
this invention, mounted on a label applying machine, a portion of
which is shown fragmentally;
FIG. 2 is a side elevational view of the device FIG. 1;
FIG. 3 is a sectional view taken substantially along the plane
designated by the line 3--3 of FIG. 1 and drawn to a larger scale
than FIGS. 1 and 2;
FIG. 4 is an enlarged detailed sectional view of the end plate and
aperture therein for ejecting the adhesive;
FIG. 5 is an enlarged perspective view of the label supporting shoe
and a portion of the drum carrying the shoe with parts exaggerated
for clarity of illustration;
FIG. 6 is a sectional view taken substantially along the line 6--6
of FIG. 5;
FIG. 7 is a view of the backside of a label showing somewhat
diagrammatically the assumed pattern of the adhesive after it has
been ejected thereon and before the label is applied to a
surface;
FIG. 8 is a view similar to FIG. 7 showing the assumed pattern of
the adhesive after application of the label to a surface in the
absence of a dam and ribs according to this invention; and
FIG. 9 is a view similar to FIG. 8 but showing the assumed pattern
of the adhesive after application of the label to a surface when a
dam and ribs are utilized.
DESCRIPTION OF THE PREFERRED EMBODIMENT
General Environment
Referring now to the drawings, and for the present to FIGS. 1 and
2, an adhesive applying device, designated generally as 10, is
shown incorporated in a label applying machine, a portion of which
is shown fragmentally at 12.
In the device as utilized in the preferred embodiment, the machine
delivers single labels successively to a rotating drum 14 at about
the 3 o'clock position as viewed in FIG. 2. The drum 14 is provided
with a label support shoe 15 which has a series of openings 16
connected to a low pressure apparatus, not shown, to thereby create
a pressure differential at the shoe surface. The pressure
differential holds each label, one of which is shown in phantom at
18 in FIG. 1, against the shoe as the drum rotates
counter-clockwise as viewed in FIG. 2. As the drum rotates, it
carries each label 18 past an adhesive applying station, designated
generally as 20, at about the 9 0'clock position as viewed in FIG.
2, where adhesive is applied by the adhesive applying device 10 to
the exposed rear or underside surface of the label. The label is
then rotated by the drum into contact with a mailing piece, such as
a magazine shown in phantom in FIG. 2 at 22, at the 6 o'clock
position where it is applied to the mailing piece. The mailing
pieces 22 are transported in synchronized relationship with the
drum to pass a mailing piece 22 upon each rotation of the drum.
Glue Applicator
Turning now to the adhesive applying device 10, said device
includes an adhesive reservoir in the form of a removable and
replaceable plastic bottle 24 which through a tube 26 supplies
adhesive to an applicator head, designated generally as 30. The
adhesive is ejected in discrete streams from the applicator head by
actuation of an actuating arm 32, pivotally mounted at one end
thereof by a pivot pin 34, shown in FIG. 1. The actuating arm 32 is
operable by means of a cam assembly 36 which is carried by the drum
14. A roller cam follower 37 is mounted on arm 32. As the cam
assembly 36 rotates past the 9 o'clock position the cam assembly
strikes roller cam 37 causing the arm to pivot around the pin 34.
The arm 32 operates associated pumping apparatus to cause an
emission of metered adhesive from the applicator head 30.
The structure of the adhesive applying device which will cause the
emission of the adhesive is shown in detail in FIGS. 3 and 4. The
applicator head 30 includes a main body 38 having a chamber or
cavity 40 formed therein. Cavity 40 has an outer and inner portion
divided by an annular wall or ring section 43. The cavity 40 has
disposed therein a piston assembly, designated generally as 42,
which is slidably mounted within the annular wall ring section 43.
The piston assembly 42 is retained within the cavity by means of a
snap ring 44 and is sealed within the ring section 43 by O-ring
45.
The piston assembly 42 includes a piston 46 which is biased into
contact with the snap ring 44 by means of a piston return spring 48
surrounding the ring section 43 within the cavity 40. Piston
assembly 42 is short of the depth of the cavity 40 to create an end
cavity area 40A.
The piston 46 has a partially threaded axial bore in which a sleeve
50 is threaded. The sleeve 50 has a central bore 52 at the rear or
the left hand end thereof, as viewed in FIG. 3, and counter bore 54
in front or on the right side as viewed in FIG. 3, connected to
produce a through bore or orifice. Disposed within the bore 52 is a
ball type check valve 56 which seats against O-ring seal 58. The
ball check valve 56 is normally biased into engagement with the
O-ring 58 by means of a spring 60 of a known selected preload
force. The spring 60 is retained within the bore by means of a pin
62 extending through the sleeve member. If a body of fluid is
captured in cavity area 40A, and piston 46 is forced into the
cavity, the trapped fluid can escape past the ball valve 56, but
cannot return. Thus, actuation of the piston produces a pumping
action.
A nozzle assembly, designated generally as 64, is carried in
abutment with piston 46 as a part of piston assembly 42. Assembly
64 includes a nozzle plate 66 having an aperture 68 formed therein.
See FIG. 4.
The nozzle assembly 64 is provided with a pair of arm 32 engaging
cap pins 70. A force applied to the cap pins 70 will drive the
assembly 42 into the cavity 40 and produce the pumping action. Such
pumping action will force fluid out through aperture 68. As can
best be seen in FIG. 4, the aperture 68 at the discharge end
thereof has an outwardly flaring conical configuration indicated by
the reference character 74. On the inside of the nozzle plate 66 is
a raised annular ridge 76 surrounding the aperture 68.
Referring again to FIG. 3, the cavity area 40A as viewed in FIG. 3
is supplied with adhesive duct 78 which communicates through
unidirectional check valve assembly 80 and tube 26 with the
adhesive bottle 24. Whenever piston 46 moves into cavity area 40A,
the fluid is trapped by check valve 80 and cannot escape back
through the tube 26. A second duct 82 is also provided in
communication with the cavity area 40A through a normally closed
solenoid valve 84 to the bottle 24. Hence fluid cannot normally
escape through duct 82.
In operation of the device, first assume that the left hand side of
the cavity, as viewed in FIG. 3, and the central bore 52 of the
sleeve 50 are filled to capacity with liquid adhesive. In this
condition, with movement of the piston assembly 42 to the left as
viewed in FIG. 3, the pressure in the cavity will start to
increase. The increasing pressure will close ball check valve 80 to
prevent escape of adhesive through duct 78 and valve 84 being
closed prevents adhesive from returning to the bottle therethrough.
The forces will continue to increase with the continued movement of
the piston assembly to the left until the internal hydrostatic
force exceeds the preload of the spring 60. When this preload is
exceeded, the check valve 56 will unseat from the O-ring 58 and the
hydrostatic forces will cause the adhesive within the sleeve 50 to
discharge through bore 52 and aperture 68 in a discrete stream
until the pressure has been relieved. The discharge will continue
once the preload of the spring 60 has been exceeded as long as
movement of the piston assembly 42 continues to the left. When this
movement stops, the forces will then become equalized and the
spring 60 will cause the check valve 56 to seat against the O-ring
58. Thus, a discrete specific amount of adhesive will have been
emitted from the aperture 68. The metered amount and velocity will
depend upon the preload of the spring 60 and the length of the
travel of the piston assembly 42.
Further, the rate of discharge, i.e., volume per unit time will
vary directly as the speed of movement of the piston. Hence if a
label is traveling a given speed the volume of adhesive reaching
any given location of the label can be varied by varying the speed
of movement of the piston which will thus vary the pattern of the
adhesive on the label. The speed of movement of the piston can be
controlled by the shape of the cam.
During the discharge period the bore 52 and counter bore 54 in the
sleeve 50 act as a venturi. It has been found that in this venturi
type configuration passage 52 together with the counter bore 54
helps to provide a uniform stream which will have a sharp cut-off
point at the completion of the ejection operation. If a uniform
diameter bore is utilized, the cut-off of the stream ejection is
characterized by a tendency of the device to suck back a portion of
the stream, causing the stream to "whip" and be deposited on the
equipment. Also with a uniform bore diameter the end of the stream
ejection is characterized by a relatively slow decay or decline of
forces which results in the adhesive oozing from the aperture. The
variable diameter configuration of the bore of the present
invention eliminates these tendencies by providing a quick shut off
with rapid decay of forces.
Once the force urging the piston assembly to the left is removed,
the piston return spring 48 will cause the piston assembly 42 to
return again to its full forward position as shown in FIG. 3. This
will cause a low pressure within the central bore 52 and the cavity
area 40A. This low pressure will cause the ball check assembly
cavity 80 to open, allowing adhesive from the bottle 24 to move
through the tube 26 and the duct 78 to thereby resupply the bore 52
and the cavity area 40A.
Refer to FIGS. 1 and 2. When the cam follower of actuating arm 32
is engaged by the cam assembly 36, it will be urged to the left as
viewed in the FIGS. 1 and 2 and will cause the arm 32 to pivot
about the pin 34. Arm 32 bears against the cap pins 70 and will
drive the piston assembly to the left causing a discharge of a
discrete stream of adhesive through the aperture. This discrete
stream of adhesive is aimed by aperture 68 to strike the backside
of the label at the adhesive applying station 20, thus applying
adhesive to the label.
The amount of adhesive in the stream can be changed by changing the
initial angular position of the arm 32. For example, if the arm 32
is moved pivotally clockwise as viewed in FIG. 1, it will force
against the cap screws 70 moving the piston assembly 42 to the
left. Thus, if the starting point of the piston stroke is in a
position with the arm moved clockwise, the total movement of the
piston assembly will be less. Therefore a lesser amount of adhesive
will be ejected. The more this initial amount is to the left, the
less the amount that will be emitted.
The adjustment of the arm 32 can be accomplished by means of a bolt
90 passing through the actuating arm 32 and a flange 92 on the body
38 engaged by an adjusting nut 94. The adjustment of the adjusting
nut 94 will change the angular position of the arm 32 and thereby
allow for an adjustment of the amount of adhesive to be discharged
for a particular label length.
As was indicated above, and as shown schematically in FIG. 3, the
valve 84 is a normally closed solenoid valve which can be opened by
the solenoid action thereof. This solenoid action is controlled by
a photoelectric cell which is shown schematically at 96, and is
used to cause recirculation of the adhesive in preference to
emission when a label is not in proper position or is missing. The
photoelectric cell is positioned and aimed at the rotating drum 14
so as to scan a given position thereon at selected periodic
intervals to detect the presence or absence of a label with each
scan. If the scan detects the presence of a label, the solenoid is
not actuated, and the valve remains closed. However, if the
photoelectric cell detects the absence of a label at the given
position on the scan, it will actuate the solenoid to open the
valve. At the open condition of the valve, when the piston assembly
42 is moved to the left, the adhesive within the bore 52 and the
left hand portion of the cavity area 40A will flow through the
passage 82 and the open valve 84 back to the bottle 24, since this
is the path of least resistance because of the preload in the
spring 60. Thus the cam assembly 36 will actuate the actuating arm
32, the point of the actuation being related to the position which
a label should occupy; however, when there is no label or when the
label is out of such position even though the cam is actuated,
ejection will be prevented by recirculation of the adhesive.
As can be seen in FIG. 2, the cam assembly 36 is comprised of a
pair of identically shaped cam members which are slidably mounted
on bolts 98. These bolts can be loosened so that the cams can be
moved to adjust their position. It is apparent therefore, that the
cams can be slid so that they are in fact coincident with each
other, in which case, each rotation will provide a single cam
actuation of the device. However, if the cams are spaced as shown
in FIG. 2, for each rotation there will be a double actuation, this
type of actuation may be desirable whenever a relatively long label
is being utilized, and thus it will be given a double application
of adhesive.
If a wider label is used than can be covered by a single stream of
adhesive, a second aperture similar to aperture 68 can be formed
beside it so that a double stream is emitted on each actuation.
One of the outstanding advantages of the present invention is the
ability of the device to be used intermittently with relatively
little, if any, maintenance required before each start-up, even
with hours or several days lapse between usage. At most, all that
is required is that any uncovered bubble which is apparent
externally around the aperture 68 be removed, and with the present
configuration of the device, even this is usually not necessary.
The annular ridge 76 around the aperture internally of the device
acts as a dam, or stop, which prevents seeping of the adhesive
through the aperture 68 during down time, so that there usually is
no encrusted bubble to remove. The flaring conical portion, or
chamber 74, also helps to prevent the formation of a bubble.
Referring now to FIGS. 5 and 6, the improved label support shoe 15
is shown in detail. The shoe 15 has an arcuate surface 100 and a
pair of spaced ribs 102 at opposite sides thereof extending
longitudinally in the direction of travel of the shoe. These ribs
preferably are raised 0.003 - 0.005 inch above the surface 100, for
conventional weight labels and are shown exaggerated for clarity of
illustration.
Openings 16 are provided in the ribs 102 through which a low
pressure is applied to hold a label on the shoe 15 by pressure
differential. A label 18 is shown in phantom outline in FIG. 5
The shoe 15 has a raised ridge, or dam 104, extending upwardly from
the surface 100. Assuming the use of labels of conventional
thickness the dam 104 preferably extends upwardly about 0.012 inch,
but is shown greatly exaggerated for illustration purposes. The dam
104 extends transversely across the surface 100 and is located
nearer the leading edge of the label than the trailing edge thereof
when the label is supported on the shoe.
The dam 104 is provided for the purpose of obtaining a better
spread or distribution of adhesive at the leading edge of the
label, and the ribs 102 are provided to minimize any tendency of
the adhesive to squeeze out of the sides of the label.
How these objective are achieved can be best understood by
reference to FIGS. 7 through 9.
FIG. 7 shows the rear of a label having had ejected thereon a
discrete amount of adhesive. The rotation of the head 14 and the
pattern of the adhesive ejection causes the adhesive to assume a
pattern as diagrammatically shown in solid outline having an
enlarged "head" with a narrow "tail."
If the surface supporting the label were perfectly flat, the
adhesive would spread generally in the pattern shown by dotted
outline in FIG. 8 when the label is applied to a surface. As can be
seen the adhesive spreads out generally toward and eventually to
the edges of the label toward the trailing edge thereof. Hence the
corners of the label at the leading edge are free of adhesive and
thus not firmly adhering to the labeled piece. Also toward the
trailing edge the adhesive tends to squeeze out from the side
edges.
FIG. 9 shows how the dam 104 and the ribs 102 greatly improve the
resultant adhesive pattern when the label is applied. The ribs
retain the adhesive and thus prevent the tendency of the adhesive
to spread past the edges.
Additionally, the dam 104 provides a barrier, which meters the
adhesive squeezing past the dam thus the pressure instead of
causing this leading part of the head to flare out toward the tail,
actually causes the adhesive to return flow forwardly and evenly,
as shown in dotted outline thereby providing adhesive to the
corners of the leading edge of the label.
Thus according to the present invention, reliable adhesive applying
devices are provided which can be easily adjusted to accommodate
many variable conditions and label sizes and which require little
maintenance or preparation for use even after extended down
time.
* * * * *