U.S. patent application number 10/915811 was filed with the patent office on 2006-02-16 for apparatus for release of thin coated sheets from a roller coating machine.
Invention is credited to Alfonso A. Mora, James C. Walker.
Application Number | 20060033264 10/915811 |
Document ID | / |
Family ID | 35799262 |
Filed Date | 2006-02-16 |
United States Patent
Application |
20060033264 |
Kind Code |
A1 |
Walker; James C. ; et
al. |
February 16, 2006 |
Apparatus for release of thin coated sheets from a roller coating
machine
Abstract
The present invention obviates the use of a vacuum while
providing reliable release of thin coated sheets from roller
coating machines. Reliable release of a coated sheet is achieved by
using dual sets of air nozzles, one set producing a constant flow
of a sheet of air and the other producing a short pulse of a sheet
of air at an appropriate time in the travel of the front edge of
the sheet through the rollers. An optical sensor is employed to
provide the properly timed signal to initiate the pulsed air blast.
The respective sets of nozzles are configured to position the
nozzles in two rows, one above the other, with offset or
alternating horizontal positioning so that nozzles of one set do
not interfere with nozzles of the other set. Each set of nozzles is
connected to a common plenum or air bar extending in parallel
relation to the rollers. Each such plenum or air bar is connected
to an air pressure source by suitable regulators, filters,
solenoids, valves, hoses and connectors.
Inventors: |
Walker; James C.;
(Huntington Beach, CA) ; Mora; Alfonso A.;
(Pasadena, CA) |
Correspondence
Address: |
LEONARD TACHNER, A PROFESSIONAL LAW;CORPORATION
17961 SKY PARK CIRCLE, SUITE 38-E
IRVINE
CA
92614
US
|
Family ID: |
35799262 |
Appl. No.: |
10/915811 |
Filed: |
August 9, 2004 |
Current U.S.
Class: |
271/309 |
Current CPC
Class: |
B65H 29/54 20130101 |
Class at
Publication: |
271/309 |
International
Class: |
B65H 29/54 20060101
B65H029/54 |
Claims
1. In a roller coating machine having a plurality of rollers for
coating thin sheets of material and a conveyor belt for
transporting the sheets as they exit the rollers, an apparatus for
promoting release of the sheets from the rollers for transfer onto
the conveyor belt; the apparatus comprising: a first plurality of
air nozzles positioned adjacent said rollers where each said coated
sheet exits said rollers, said first plurality of air nozzles
creating a layer of constant air flow towards each said sheet; and
a second plurality of air nozzles positioned adjacent said rollers
where each said coated sheet exits said rollers, said second
plurality of air nozzles creating a layer of pulsed air flow
towards a front edge of each said sheet.
2. The apparatus recited in claim 1 wherein said first and second
pluralities of nozzles are positioned adjacent one another.
3. The apparatus recited in claim 1 wherein said first and second
pluralities of nozzles are positioned one above the other relative
to each said coated sheet.
4. The apparatus recited in claim 1 wherein said first and second
pluralities of nozzles are positioned in an alternating
configuration so that air layers of the respective pluralities of
nozzles do not substantially affect each other.
5. The apparatus recited in claim 1 wherein each of said
pluralities of nozzles is connected to a respective air plenum for
delivering pressurized air to said nozzles.
6. The apparatus recited in claim 5 wherein each said air plenum is
positioned in parallel to the axes of said rollers.
7. The apparatus recited in claim 5 wherein each said air plenum is
connected at its respective ends to a source of pressurized
air.
8. The apparatus recited in claim 5 wherein each said air plenum is
connected to a source of pressurized air through a solenoid valve
for selectively switching air flow to said plenum on and off.
9. The apparatus recited in claim 1 further comprising a sensor for
generating a signal in response to passage of each said sheet
through said rollers and means for receiving said signal to
initiate said pulsed air flow of said second plurality of air
nozzles.
10. A method for releasing thin coated sheets from the rollers of a
roller coating machine, the method comprising the following steps:
directing a layer of constant air flow toward each said coated
sheet as the sheet exits the rollers; and directing a layer of
pulsed air flow toward a front edge of each said coated sheet as
the sheet exits the rollers.
11. The method recited in claim 10 wherein each of said directing
steps is carried out simultaneously during said pulsed air
flow.
12. The method recited in claim 10 further comprising the step of
sensing the passage of each said sheet through said rollers for
initiating said pulsed air flow.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an apparatus used with
roller coating machines to facilitate release of thin coated sheets
from the rollers and deposition of those sheets onto a conveyor
belt adjacent the rollers. More specifically, the invention
disclosed herein relates to the improved use of directed air flow
to release a coated thin sheet from a roller so that it may be
transported on an adjacent conveyor belt.
[0003] 2. Background Art
[0004] The most relevant prior art appears to be U.S. Pat. No.
4,397,258 to Dremel. Dremel discloses an apparatus that
accomplishes the same function as the present invention. It
accomplishes this function by employing an air nozzle and a vacuum
pump in combination. They operate together to force a coated thin
sheet from the roller and attract the sheet onto the conveyor belt.
Unfortunately, there are a number of distinct disadvantages to
using a vacuum to assist the sheet release process. First and
foremost, employing a suction device in an inherently dusty
environment creates maintenance problems. The vacuum pump also
attracts dust and debris which has to be filtered or otherwise
cleaned regularly to avoid clogging and reduction in performance.
Secondly, a vacuum is more difficult to achieve and to locate
accurately, particularly over an extensive area. Thirdly, the
conveyor belt has to be designed to permit air flow therethrough to
allow suction to affect the sheets.
[0005] For these and other reasons, it would be highly advantageous
if it were possible to achieve reliable thin sheet release from a
roller coating machine without the need to use a vacuum.
SUMMARY OF THE INVENTION
[0006] The present invention obviates the use of a vacuum while
providing reliable release of thin coated sheets from roller
coating machines. It accomplishes this advantageous avoidance of
the use of a vacuum pump by employing a novel combination of air
output nozzles positioned in close proximity to the coated sheet as
it exits between upper and lower coating rollers. It has been found
that reliable release of a coated sheet is achieved by using dual
sets of air nozzles, one set producing a constant flow of a sheet
of air and the other producing a short pulse of a sheet of air at
an appropriate time in the travel of the front edge of the sheet
through the rollers. An optical sensor is employed to provide the
properly timed signal to initiate the pulsed air blast. The
respective sets of nozzles are configured to position the nozzles
in two rows, one above the other, with offset or alternating
horizontal positioning so that nozzles of one set do not interfere
with nozzles of the other set. Each set of nozzles is connected to
a common plenum or air bar extending in parallel relation to the
rollers. Each such plenum or air bar is connected to an air
pressure source by suitable regulators, filters, solenoids, valves,
hoses and connectors. Because there is no need for a vacuum,
maintenance is required less frequently, all air flow effects can
be positioned close to the edge of the exiting sheet and the
conveyor belt design does not have to accommodate air flow through
the belt.
[0007] As used herein the terms "layer of air" and "sheet of air"
refer to air flow in a generally planar configuration achieved by
employing an array of nozzles each having a linear distribution of
nozzle jets or orifices.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The various embodiments, features and advances of the
present invention will be understood more completely hereinafter as
a result of a detailed description thereof in which reference will
be made to the following drawings:
[0009] FIG. 1 is a three-dimensional view of a preferred embodiment
of the present invention;
[0010] FIG. 2 is a top view of the preferred embodiment;
[0011] FIG. 3 is an elevation view thereof;
[0012] FIG. 4 is a cross-sectional view taken along lines 44 of
FIG. 3;
[0013] FIG. 5 is a back mechanical layout drawing of the preferred
embodiment;
[0014] FIG. 6 is a front mechanical layout drawing thereof; and
[0015] FIG. 7 is a graph of air blast timing of the preferred
embodiment.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0016] Referring to the accompanying figures and specifically to
FIGS. 1-6, it will be seen that a roller coating machine 10
comprises three rollers 12 (including conventional metering,
application and opposed rollers) configured between structural
members 14 and 16 for coating one side of a thin sheet and
depositing it on a moving conveyor belt 18.
[0017] The invention herein comprises an air sheet release system
15 which in the preferred embodiment utilizes plenums 20 and 22
positioned adjacent the rollers and having respective sets of air
nozzles 24 and 26 pointed at the edge of each sheet as the sheets
exit the rollers as seen best in FIG. 4. As will be seen
hereinafter in conjunction with FIG. 7, the upper nozzles 24 emit a
timed pulse of air while the lower nozzles 26 emit a constant or
steady state air flow to prevent each sheet from failing to release
from the rollers 12.
[0018] As seen best in FIGS. 5 and 6, (only one plenum is shown for
clarity) each plenum 20 and 22, terminates at its respective ends
in connector elbows 32 which are, in turn, connected to air hoses
34 joined at a tee 36. The tee 36 is connected to an air source
through a filter 38, a regulator 40 and a solenoid valve 42. In
addition, each air nozzle 24, 26 may preferably comprise an
adjustment valve 30 to permit contouring of the various nozzle air
flows to have the desired effect on reliable sheet release. The
individual nozzles are preferably of the type having a linear array
of apertures so that the combined air flow is in the form of a
sheet of air that runs parallel to the front edge of the coated
sheet exiting from rollers 12.
[0019] In the preferred embodiment of the present invention, each
of the air nozzles 24, 26 is a LECHLER Model 600.130.BC plastic
pneumatic spray nozzle which has a linear array of sixteen one
millimeter orifices.
[0020] As shown graphically in FIG. 7, in the preferred embodiment
of the present invention, the lower set of air nozzles 26 emit a
constant flow at about 10 psi while the upper set of nozzles 24
emit a single pulse of air flow at about 20 psi. The single air
pulse is emitted in response to a sensor positioned relative to
rollers 12 to emit a signal indicating the imminent travel of a
sheet through the rollers. This signal is transferred to a
monostable multivibrator (not shown) and solenoid valve 42 responds
to the multivibrator to enable a single air pulse for a selected
length of time as the sheet edge begins to exit the rollers as
shown in FIG. 14. The constant air flow nozzles 26 do not require a
sensor or multivibrator since they need not respond to each
individual sheet.
[0021] Having thus disclosed a preferred embodiment, it will be
understood that variations are contemplated including for example
the number and position of air nozzles as well as the air pressures
and timing. Accordingly, the scope hereof is to be limited only by
the appended claims and their equivalents.
* * * * *