Note: Descriptions are shown in the official language in which they were submitted.
CA 02534044 1995-06-08
AUTOMATED APPARATUS AND METHOD FOR PREPARING
1 . CONTACT LENSES FOR INSPECTION AND PACKAGING
1. Field of the Invention
The present invention relates generally to the
field of manufacturing ophthalmic lenses, especially
molded, hydrophilic contact lenses, and more
specifically to an automated apparatus for handling and
preparing contact lenses 'or inspection and packaging.
2. Description of the Prior Art
The ~olding of hydrophilic contact lenses is
disclosed in U.S. Patent No. 4,495,313 to Larsen; U.S.
Patent No. 4,640,489 to Larsen, et al.; U.S. Patent No.
4,680,336 to Larsen et al.; U.S. Patent No. 4,889,664 to
Larsen et al.; and U.S. Patent No. 5,039,459 to Larsen
et al., all of which are assigned to the assignee of the
present invention.
These prior art references disclose a contact lens
production process wherein each lens is formed by
sandwiching a monomer or monomer mixture between a front
curve (lower) mold section and back curve (upper)~mold
section, carried in a two by four mold array. The
monomer is polymerized, thus forming a lens which is
then removed from the mold sections and further treated
in a hydration bath and packaged for consumer use.
U.S. Patent Nos. 5,080,839 and 5,094,609 disclose
respectively a process for hydrating contact lenses and
a chamber for hydrating contacts lenses formed with a
monomer or monomer mixtures disclosed in the forgoing
patents. The process disclosed in these patents
significantly reduces the thruput time by hydrating the ,
lens and releasing the lens from the mold cavity with
CA 02534044 1995-06-08
-2-
the deionized water and a small amount of surfactant without
any salts, so that the time consuming ionic neutralization of
the polymer from which the lens blank is made does not occur
during the hydration process. When deionized water is used,
the final step of the process is to introduce buffered saline
solution into the final package with the lens and then seal
the lens within the package so that the final lens
equilibrium (ionic neutralization, final hydration and final
lens dimensioning) is accomplished in the package at room
temperature or during sterilization.
U.S. Patent No. 4,961,820, also assigned to the
assignee of the present invention, discloses a final package
for a contact lens, wherein the package is formed from a
transparent polypropylene blister and a foil laminate that is
Z5 heat sealed thereto.
While U.S. Patents 5,080,839 and 5,094,609 contemplate
that the entire hydration process and transfer to final
packaging may take place in a fully automated fashion, and
while the chamber and process described in the foregoing
patents enabled automated handling of the lens during
hydration, suitable automated equipment to prepare the lenses
for inspection and to handle the lenses at high production
rates to implement the methods thereof in a fully automated
apparatus was not readily available or taught by the prior
art.
SUI~HARY OF THE INVENTION
Recent developments in the inspection of contact lenses
produced in accordance with the foregoing methods has enabled
automated lens inspection, as taught in EP 0 604 179,
entitled "Lens Inspection Method and'Apparatus°, (VTN 0037) ,
assigned to the assignee of the present invention. Further,
CA 02534044 1995-06-08
-3-
recent developments in the hydration and automated handling
of wet contact lenses, as taught in U.S. Patent No. 5,476,111
"Automated Method and Apparatus for Hydrating Soft Contact
Lenses" (Docket 8998), also assigned to the assignee in the
present invention, has enabled automatic robotic handling of
lenses during hydration, and prior to the inspection thereof
by the automated lens inspection system.
It is an object of the present invention to provide an
automated apparatus for handling and preparing contact lenses
for inspection. it is further an object of the present
invention to provide an automated apparatus for handling and
preparing contact lenses for inspection and packaging wherein
., the lenses are inspected and packaged in the same carrier.
It is an object of the present invention to provide a
robotic device for transferring a plurality of soft contact
lenses from a first processing station to a second processing
station wherein the robotic device includes an adjustable
array of convex contact lens carriers thereon. The adjustable
array is particularly useful for transferring contact lenses
between processing stations wherein the first station
includes a plurality of first contact lens carriers arranged
in a first array with each of said carriers having a concave
lens holding surface and a contact lens to be transferred
therein. Each of these concave lens holding surfaces may also
define a first fluid port for introducing a fluid between the
concave surface and the lens. The robotic head which
facilitates transfer of the lens between the processing
station includes a plurality of second contact lens carriers
in an adjustable array with each of the second carriers
having a convex lens attachment surface which receives a
contact lens thereon, and a second port for introducing
CA 02534044 1995-06-08
-4-
a fluid between the contact lens and the convex lens
1 convex surface. The robotic device may be equipped with
articulated motorized arms and a control circuit for
moving the robotic transfer head between the first and
the second processing stations, and may further include
a fluid Supply means for supplying a fluid to the first
and second fluid ports to thereby transfer the lens
therebetween. The second processing station may include
a second frame having a plurality of third contact lens
carriers arranged thereon in a third array for receiving
the contact lenses transferred thereto, wherein the
' arrangement of thfrd array of contact lens carriers is
not the same as the arrangement as the first array of
first contact lens carriers, and the robotic transfer
head includes an adjustable array for matching the first
frame for contact lens pickup, thus changing its
configuration to match the second frame for contact lens
discharge.
It is further an object of the present invention to
provide for transfer of the lens between carriers with
~ degassed and deionized water to facilitate the
inspection thRreof in the automatic inspection means.
It is further an object of the present invention to
provide a device for removing air bubbles that may have
formed on the surface of the lens prior to the
inspection thereof in the automatic lens inspection
system.
It is further an object of the present invention to
provide an improved method of inspecting molded contact
lenses wherein the lenses are inspected in deionized and
3~ degassed. water to minimize the formation of air bubbles
which would create false negative automatic lens
inspection data.
It is further an object of the present invention to~
provide an improved method for manufacturing soft
CA 02534044 1995-06-08
-5-
contact lenses wherein the lenses are first molded in
disposable contact mold frames, and then hydrated and
inspected in degassed and deionized water, and then
packaged in a saline solution to enable the. time consuming
ionic neutralization of the polymerized lens to occur in
the final package. It is further an object of the present
imrention to provide the foregoing method of manufacturing
with a consolidation step for removing defective lenses
from the line of inspected lenses prior to packaging.
It is another object of the present invention to
provide far inspection of the contact lens in degassed and
deionized water and to provide for the automatic removal of
the deionized water following inspection thereof.
Finally, it is an object of the present invention to
provide for a transfer of the contact lenses from the
hydration station to the inspection station with a bubble
blow off station to remove air bubbles that would otherwise
create false negative automatic lens inspection reports.
While the invention is described with particular
reference to molded contact lenses wherein the lens has
been molded between a first and second mold half, as
described in U.S. Patent No. 5,804,107 "Consolidated
Contact Lens Molding" (Docket 9016) it is understood the
present consolidation apparatus is equally suitable for the
consolidation of lenses formed by lathe cutting wherein the
hydrogel is maintained at a dry state while the desired
optical surfaces are cut and polished. Further, the
apparatus of the pz~esent invention may also be used in
consolidating spin cast lenses which subject a liquid
monomer to centrifugal force in a mold which has the same
shape as the desired optical surfaces of the lens.
CA 02534044 1995-06-08
BRIEF DESCRIPTION OF THE DRAWINGS
1
The foregoing objects and advantages of the present
invention for an automated apparatus and method for
consolidating products for packaging may be more readily
understood by one skilled in the art with reference
being had to the following detailed description of the
preferred embodiments, taken in conjunction with the
accompanying drawings, wherein like elements are
designated by identical reference numerals thzoughout
the several views, and in which:
Figure 1 is a diagrammatic and plan view of an
apparatus which fills a package carrier with degassed
deionized water, removes the molded contact lenses from
the final hydration stage, and places the contact lenses
in a specially configured inspection pallet for the
automatic optical inspection thereof.
Figure Z is an elevation view of the automated lens
inspection system and the stations utilized in.the
handling of the lenses after hydration and prior to the
~ automated lens inspection. .
Figure 3 is a plan view of the apparatus
illustrated in Figure 2.
Figure 4 is an elevation view of a consolidation
buffer used in the present invention, and the packaging
apparatus to which the consolidated product flow is
transferred.
Figure 5 is a plan view of the apparatus
illustrated iii Figure 4 illustrating both a
consolidation buffer and a packaging buffer arranged
3a immediately prior to the packaging apparatus.
Figure 6 is a plan view of an articulated robotic
transfer head having an adjustable array of convex lens
carriers positioned immediately above a hydration
carrier having a plurality of contact lenses therein.
CA 02534044 1995-06-08
-7-
Figure 7(a) is a cross-section and diagrammatic
1 illustration of the transfer of a wet contact lens from
the concave lens holding surface of a hydration carrier
to the convex holding surface of the articulated robotic
transfer head.
Figure 7(b) is a cross-section and diagrammatic
illustration of a bubble blow off mechanism for removing
air bubbles from the contact lenses that might otherwise
create false negative automatic lens inspection results.
Figure 8 is a diagrammatic and partially cross-
section plan view of the articulated robotic transfer
head in the expanded position, as viewed from above.
Figure 9 is a diagrammatic and partially cross-
aectioned illustration of the articulated robotic
transfer head in plan view in a closed position, as
r 15 illustrated from below.
Figure 10 is an isometric view of a contact lens
carrier which serves as both an inspection carrier, and
a portion of the final contact lens package.
Figure 11 is an isometric view of an inspection
carrier used to transport a pluraffty~of the contact
lens carriers illustrated in Figure 10 through the
automated lens inspection system.
Figure. l2 is a diagrammatic illustration
illustrating the components of the deionized.water
degassing system of the present invention.
Figure 13 is a detailed elevation view illustrating
in section the degas unit used to degas the deionized
water.
Figure 1~! is an elevation and side view of an
apparatus used for filling package carriers with
degassed and deionized water in accordance with the
practice of the present invention.
Figure 15 is a partially cross-section elevation
and end view of the apparatus illustrated in Figure 14.
CA 02534044 1995-06-08
-g_
Figure 16 is a diagrammatic illustration of on
individuated robotic handling device transporting contact
lens carriers to a vacuum rail consolidation buffer used
in the present invention.
Figure 17 is a diagrammatic illustration
illustrating in conceptual form a consolidation buffer
used in the present invention.
Figure 18 is an elevation view of a vacuum rail
consolidation buffer used in the present invention.
Figure 19 is an enlarged plan view of the drive
mechanism utilized in the vacuum rail consolidation
mechanism of Figure I8.
Figure 20 is a diagrammatic and partially cross-
sectioned illustration of the apparatus used to fill the
package carriers with saline solution in the final
packaging of the present invention.
Figure 21 is a partially cross-section and
diagrammatic elevation front view of a heat sealing head
and pneumatic press used to hermetically seal the package
carrier of the present~invention.
Figure 22 is a partially cross-sectioned
elevational side view of the apparatus illustrated in
Figure 21.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention was designed for and is
particularly adapted for use in the post hydration
processing section of an automated contact lens
production facility. Contact lenses molded in an
automated production line, such as that described in co-
pending U.S. Patent No. x,804,107, entitled "Consolidated
Contact Lens Molding"; hydrated in a hydration system as~
CA 02534044 1995-06-08
_g_
described in EP 0 686 491, entitled "System for Handling
Contact Lenses During Hydration"; and automatically
inspected as described in EP 0 604 179, entitled "Lens
Inspection Method and Apparatus" are particularly
benefited by the present invention.
POST HYDRATION PROCESSING
The present invention envisions a~multi-purpose
disposable lens package carrier which transports a
contact lens during inspection thereof, and serves as a
portion of the final packaging after inspection.
A suitable package carrier 20 is illustrated in
Figure 10 and is formed from injection molded or thermal
formed plastic sheet material, such as polypropylene and
includes a planar essentially rectangularly shaped base
member 34 having an angularly depending wall portion 38 at
one end thereof forming a first flange member and a pair
of registration flanges 33(a),33(b), one of which is
visible in Figure 10, at the other end thereof which are
used to align the package carrier for robotic handling.
This package carrier is more fully described in copending
application U.S.S.N. 995,607. Registration notches
31(a),(b) are provided on either side of the base 34 to
cooperate with registration pins on various sugport
pallets used in the processing and packaging operations
to register the package carrier and lens for further
handling or treatment. Offset from the center of the
package is a cavity 36 integrally formed therein which is
of an essentially semi-spherical configuration, generally
in conformance with a curvilinear shape of a contact lens
(not shown) which is adapted to be stored therein in a
sealed condition while immersed in a suitable sterile
CA 02534044 1995-06-08
-10-
aqueous solution in a manner similar to that described in
U.S. Patent No. 4,691.820 to Martinez; which is assigned
to the assignee of the present invention. The height "h"
of flange member 38 depending from the planar base member
34 is complimentary to the height or depth of cavity 36,
and~provides for self alignment of the package carrier in
cooperation with depending flanges 33(a),(b) on specially
configured pallet carriers, as will hereinafter be
described. Depending flange 38 is also used in the final
packaging of the product in cooperation with a plurality
of generally "chevron-shaped" ridges 32, which will
subsequently assist in supporting the cavity structure of
an inverted and superimposed package carrier when said
packages are to be cartoned for final distribution.
The cavity 36 also includes a plurality of tick
marks 37 which are used to assist in holding a contact
lens in the centered position in the cavity during the
removal of deionized water at one of the post hydration
processing stations. The package carrier is also equipped
with an annular flange 39 which is used for heat sealing
a foil laminate cover in order to provide a hermetic seal
for the contact lens during final distribution. A cut-out
35 is used to facilitate gripping the flange 38 and the
package when the cover stock or foil laminate is removed
by the consumer to use the lens.
Hase member 34 also includes a smooth planar
surface 34(a) to provide a suitable engagement zone for
vacuum grippers on the upper side, and a vacuum rail on .
the lower side, which are used to transport the package
carrier during various stages of the operation.
An inspection carrier for transporting the package
carriers through the automated lens inspection system is,
CA 02534044 1995-06-08
-11-
illustrated in Figure 11. The inspection carrier 10
includes a first and second row 10(a),10(b) of cavities
40 which receive the bowl 36 of the package carrier and
provide an optical sight path for the automated lens
inspection system. Each of the intermediate
registration pins 41 engage a package carrier on either
side, with the end registration pins 41(a) engaging a
single package. These registration pins engage the
registration notches 31(a),(b) in the package carriers
and provide for precise registration, of the package
1Q carrier in the longitudinal dimension of the inspection
carrier while a pair of hard edges 42(a),42(b) provide a
reference point for the downwardly descending flanges
33(a),33(b), which together with pins 41 register the
carrier package against rotational skewing. The
_ 15 inspection pallet 10 is further provided with three
registration openings 43 on either side of the pallet
which are used to transport the pallet through the
automatic lens inspection station and to lock the pallet
in place during loading and unloading of the package
2~ carriers. The inspection pallet is further provided
with a pair of grooves 44(a),44(b) which provide a
positive grip for an-overhead transport mechanism that
places and then removes the inspection pallet from the
automatic lens inspection system. A pair of slanted
25 faces 45 provide clearance fcr the downwardly descending
flange member 38 of the package carrier 20.
As illustrated in Figure 3, an injection mold
machine 30 is used to mold the polypropylene lens
carriers 20 which serve a dual purpose in the invention
30 concept. First, to provide a carrier for the inspection
of the lens by the automated lens inspection system, and
secondly, to provide a receptacle for the final
packaging of the lens for distribution to end use
consumers. These package carriers are molded in
CA 02534044 1995-06-08
-I2-
predetermined array, typically in a 4 X 4 cluster of
1 sixteen package carriers per mold cycle, and removed
from the injection mold by a robotic transfer means 60
having a rapidly reciprocating low mass transport
carrier 62. The carrier 62 includes a hand member 64
having a plurality of vacuum gripper means thereon which
are arranged to correspond to the array of mold cavities
within the injection molding machine 30. Carrier 62
reciprocates along support member 66 and is rotatable
from a vertical orientation as illustrated in Figure 3,
to a horizontal orientation necessary to place the
packaged carriers into a secondary transfer shuttle 6H.
. Secondary transfer shuttle 68 is used to transport a
plurality, i.e. sixteen of the package carriers from a
. first receiving position 68(a) illustrated in Figure 3
to a second positfon 6e(b) where the package carriers
are picked up by a robotic handling device 50. Robotic
handling device 50 is articulated, having first and
second nrms 51,52 and a vertically reciprocating arm and
hand (not shown) having a plurality of vacuum gripping
~ means thereon khich engage each of the package carriers
transported by the transfer shuttle 68.
The package carriers 20 are then removed from the
transfer shuttle 6B and placed on an inspection pallet
'10 at a pallet loading station 11. In the preferred
embodiment the package carriers are molded in a 4 X 4
array to maximize the efficiencies inherent in such an
array for molding, which are transported in the
inspection pallet IO in a 2 X 8 array. When these two
arrays are used, robotic handling device 50 makes two
3~ separate transfers,.and transfers a 2 X 4 array in each
transfer. The loaded pallet IO is then moved by
' conveyor 12(a) to a deionized water injection station I6 .
wherein each of the package carriers transported on the
inapectiori pallet are partially filled with degassed and' '
CA 02534044 1995-06-08
-13-
deionized water. The inspection pallet is then
transferred by a push conveyor 17 to a lens loading area
18 where it is batched with a second pallet to provide a
contiguous loading area with thirty-two package carriers,
each of which has been dosed with degassed and deionized
water.
DEIONIZED WATER DEGAS
The present invention utilizes degassed and
deionized water with a small amount of surfactant therein
as an inspection media for the Automatic Lens Inspection
System described in EP 0 686 842.
When only deionized water is used in the package
carrier bowl, friction or hydrophobic attraction between
the contact lens and the surfaces of the carrier that form
1S the recesses may occasionally prevent the lenses from
moving or sliding completely into the desired,
predetermined positions. For example, in one known
process, contact lenses are formed from a liquid hydrogel
monomer, which is polymerized in the presence of an inert
diluent such as boric acid ester, as described in U.S.
Patent No. 4,495,313. The inert diluent fills up the
spaces in the hydrogel lens during polymerization, and the
diluent is subsequently exchanged for deionized water
during a hydration process.
After this hydration process is completed, small
amounts of the acid groups may remain on the lens
surface. When the lens is placed inside the recess of the
lens carrier, these acid groups may cause the lens to
stick to the surface of the bowl of the carrier.
Without freedom of movement, the lens might not move
completely into the desired predetermined position.
When this happens and the lens is subsequently inspected
CA 02534044 1995-06-08
-14-
using an automatic Lens Inspection System, the lens may
be rejected for being outside the field of view, or may
otherwise be erroneously identified as irregular or
imperfect.
In application EP 0 686 459, entitled "A Method of
Positioning Ophthalmic Lenses", a solution to this problem
was described in which a small amount of surfactant was
added to the deionized water. The surfactant reduces the
friction and retards the hydrophobic attraction between
the lens and the surface of the holder forming the recess,
helping to insure that the lens is pulled into the
desired, gredetermined position.
Any suitable surfactant may be used in the practice
of the invention. For example, the surfactant may be
polyoxyethylene 20 sorbitan monooleate, more commonly
known as Polysorbate 80, or tween BO or tween 80k'. It has
been found that the addition of tween 80 at a
concentration as low as 25 parts per million parts of
solution allows the lens to move in package carrier 20
'20 without sticking. Larger amounts of the surfactant may
be used, and for example, the weight percent
concentration of the surfactant in the solution may be
between S.o% and 0.01%. The surfactant may be mixed in
any suitable liquid carrier, such as deionized water, to
Z5 fozm the desired solution.
Preferably, the surfactant concentration in
solution is in the lower end of the above-given range,
and for example, the surfactant concentration may be
below fifty parts per million parts of deionized water.
30 Using the surfactant at this lower concentration helps
to avoid, or to reduce, any foaming or bubbling of the
surfactant in the solution and helps to reduce
CA 02534044 1995-06-08
-15-
subsequently the surfactant concentration below a
1 predetermined level.
Degassed water is preferred to the prevent the
formation of air or gas bubbles when the water emerges
from a pumped high pressure fluid line into a low
pressure (atmospheric) environment. When deionized
water which has not been degassed is used, small air
bubbles may form in the package before the lens is
transferred or, on the contact lens when it is
transferred to the package carrier. These bubbles are
f°~ed from dissolved gasses in the deionized water
which are "seeded" by the lens or a small irregularity
in the package carrier surface.
The apparatus for degassing the deionized water is
illustrated in Figures 12 and 13. Figure 12 is a
diagrammatic illustration of the degas module, while
Figure 13 is a detailed elevation view as the degas
unit. Deionized water is provided through input line
112 from a deionized water source, which. may be the same
source as that used for hydration. If drawn from a
container, a optional pump 114 may be provided.
The deionized water then passes through filter 118
in order to remove extraneous particulate contaminates
that may be present in the water.
The deionized water is then provided to the inlet
I2I of the degas unit 122. Within the degas unit, the
deionized water is divided among a plurality of tubes
124, and then recombined into a degas unit discharge
126. The degas unit is operated under a low ambient
pressure typically from 4 to 25 torr which is provided
by vacuum pump 128. This vacuum pump is attached to the
degas unit 122 by line 130 and discharges the excess air
from the degas unit by way of line 132.
After the deionized water exits degas unit 122 by
- ~ discharge line 126, it passes through line 136(a),(b)
CA 02534044 1995-06-08
-16-
into manifolds 138(a),(b). The manifolds are used as a
1 common source to supply a plurality of precision dose
pumps 140 that fill individual contact lens package
carriers at the dosing station 16 and the robotic
transfer array 102 mounted on robotic transfer device
100. The pumps 140 used to pump the degassed and
deionized water to manifold 138 are F.M.I. pumps (Fluid
Metering, Inc., Oyster Hay, New York) that are mounted
to drive units manufactured by Oyster Hay Pump Works,
Inc., Oyster Hay, New York. These pumps provide
precision doses of degassed and deionized water solution
to pre-wet the package surface thereby reducing bubble
formation and lens sticking, to avoid overfilling (i.e.
water on the. sealing area of the package) and to promote
the proper water level for the inspection system.
Turning now to Figure 13, there fs shown in greater
detail the monomer degas unit 122. The degas unit is
comprised of a pressure boundary consisting of an outer
cylindrical wall 144, a tap plate 146 and a bottom plate
148. Contained within the cylindrical side wall 144 is
~ a port 130, which is connected to vai.~um pump-128~(not
shown).
Top plate 146 and bottom plate 146 are attached to
the cylindrical side walls 144 by use of flanges 150
compressed upon O-rings 152 and 154 found on the bottom
and top plates, respectively. Compression of the O-
rings and attachments of plates 146 and 148 to flanges
150 is accomplished by bolts 156 that attach the plates
to the flanges.
Passing through top plate 146 is the water inlet
3~ line 121. This inlet line.passes through the top plate
146, divides within the chamber 122 by means of a "Y"
connector into two or more lines 157 of equal length.
Lines 157 are preferably of equal length in order to
provide equal back pressure resulting in equal flow
CA 02534044 1995-06-08
- 17-
through both lines to two separate headers 158. Each of these
headers is connected to ten silicon tubes 160 which are
permeable to gas. The tubes 160 are arranged in a 3-4-3 offset
array, 0.300 spacing center-to-center. The flow through the
tubes is from the bottom up in order to fill the tubes and not
entrain voids in the liquid. A static mixer 170 is provided in
each of the tubes 160 to increase the efficiency of mass
transfer. These static mixtures are made of Delrin~, 1/4 inch
in diameter and 6 inches long, as produced by Kof lo, Inc . of
Carrie, Ill.
The internal structure of the degas unit stands off the
bottom of chamber with stainless steel pipe 167 supporting
Delrin~ blocks 168 at the desired separation and these blocks,
in turn, support manifolds 158 and 162 containing therebetween
extended gas permeable tubes 160. Alternately the degas unit
may be suspended from top flange 146.
During its time of residence in the silicon tube 160 in
the low pressure degas chamber 144, dissolved gasses migrate
out of the deionized water through tube wall 160, drawn out by
the vacuum pump through chamber outlet 130. As the water
approaches the top of the chamber it is essentially free of
dissolved gasses.
The silicon tubes near the top of the chamber are
connected to second headers 162 which combine silicon tubes
160 back into common tubes 164. These tubes may also be made
of a silicon, or may be made of an impervious material. They
are of the same length in order to avoid pressure differences
which could result in flow imbalances. Tubes 164 are then
connected in a "Y" fashion to provide a single degas unit
outlet 26.
The preferred material for the gas permeable tubing is
STHTTM tubing produced by Sanitech Inc. of Andover, N.J.
CA 02534044 1995-06-08
-18-
from Q74780 medical grade silicone rubber manufactured by
Dow Corning of Midland, MI.
The apparatus is arranged so that each set of tubes
124 contains ten tubes, each 1/4 inch inner diameter with
a wall thickness of 1/32 inch, having a 80 durometer
hardness.
PRE-INSPECTION PREPARATION
The apparatus of the present invention that
prepares the contact lenses for inspection and subsequent
packaging is best illustrated in Figure 1 which is an
enlarged view of a portion of the apparatus illustrated in
Figures 2 and 3 with particular emphasis on the transition
between the hydration line and the post-hydration line of
the present invention.
The present invention is particularly adapted for
use in conjunction with the invention disclosed in U.S.
Patent No. 5,476,111, entitled "Automated Method and
Apparatus for Hydrating Soft Contact Lenses", assigned to
the assignee of the present invention.
As illustrated in Figure 1, a second hydration
carrier 860 having a top chamber plate mounted thereon
is advanced into the separation station 120 for removal
of the top chamber plate and transferred to the return
conveyor 141. The hydration base emerges from the
separation station 120 to the position illustrated at
860(a) having a plurality, e.g., thirty-two contact
lenses 8 therein, with a single lens carried in each of
the convex lens carriers attached thereto. An
articulated robotic transfer device 100 having an
adjustable 4 X 8 array 102 of convex lens carriers then
CA 02534044 1995-06-08
-19-
positions the array over the second hydration carrier
1 860(x) as illustrated in Figures 6 and 7(a).
1~s illustrated in Figure 7(a), a single contact
lens 8 is carried within the concave lens carrier 861
and is positioned immediately below a convex lens
carrier element 104 mounted on the 4 X 8 array 102. The
concave carrier 861 includes at least one port 862 for
introducing a fluid between the surface of the concave
lens carrier element, and the lens 8. The fluid is
supplied through a channel 866 cut into the lower side
of upper plate member 867, which communicates with a
fluid manifold and a plurality of upstanding fluid
connectors 863 which extend above the surface of the
concave lens carrier elements 861 as best illustrated in
Figure 6. The fluid connectors 863 are adapted to
engage fluid couplings. 864 formed on the underside of
the 4 X 8 array 102. Each of these couplings is
connected to a fluid conduit 874 which supplies a
transfer fluid for the transfer of the contact lens 8
from the concave lens holding means 861 to the convex
lens holding means 104.
In the embodiment illustrated in Figure 6, and in
particular for the transfer of contact lenses from the
hydration carrier 860 to the robotic array 102, a
pneumatic fluid transfer is desired, and thus conduits
8?4 provide pressurized air to the coupling members 864
which in turn supply the pressurized air to fluid
coupling 863 to the channel passageway 866, and the port
862..
As illustrated in Figure 7(a), the contact lens 8
is still wet having recently been hydrated and flushed
in the hydration station. Further, the lens has been
hydrated with deionized water having a small amount of
surfactant therein which, may be advantageously employed
to promote the handling of the wet contact lens by
- . l
CA 02534044 1995-06-08
-20-
centering the lens within the concave surface of lens
1 holding means 861. When the air pressure lines 874 are
actuated, a puff of air will emerge through the port 862
and lift the contact lens upwardly from the surface of
the concave carrier and into engagement with the convex
lens carrier element 104. While the lens will adhere to
element 104 with or without the surfactant, the
surfactant wets the surface of the convex carrier
element 104 and promotes adhesion thereto by virtue of
the surface tension of the deionized water and the
surrounding atmospheric pressure. In the transfer, it
is desirable to position each of the convex carrier
elements 104 within 1.5 mm of the lens to ensure a
direct and precise transfer.
After transfer of the lens 8 to the convex element
104, the robotic transfer device then moves the array of
lenses to a "bubble blow off" station 70 illustrated in-
Figure 3. In Figure 1, the 4 X 8 array 102 overlies
station 70.
The bubble blow off station 70 includes a manifold
arrangement similar to manifold 860_with a plurality of
cup members 105, each of which has a concave surface I08
of approximately the same configuration as the convex
surface of the second lens carrier element 104: While a
concave surface such as surface 108 has been found to be
desirable, a single jet device will also provide the
same function. The concave surface 108 also includes at
least one port 110 defined therein for admission of
pressurized fluid through a central passageway 109
formed in the cup member. The use of a small amount of
surfactant in the deionized water promotes the transfer
of the lens from first to second carrier elements, but
also enables the formation of small air bubbles 105 in
the layer of deionized hater which coats the contact
lens -8. By subjecting the lens to a jet of pressurized.
CA 02534044 1995-06-08
-21-
fluid, the small bubbles 105 are migrated outwardly and
dissipated prior to the transfer of the lens to the
inspection carrier. Removal of the air bubbles is
desirable to avoid false negative reports from the
automatic lens inspection system which is used to
inspect the lenses. While pressurized air is used in
the preferred embodiment of the invention, deionized
water is also suitable.
PACKAGE CARRIER DOSING
As was described earlier with respect to Figures 12
and 13, deionized water is degassed in a degas unit 122
ana distributed by a plurality of precision dosing pumps
140 to a deionized water dosing station 16, which is
. 15 more fully illustrated in Figures 14 and 15. As
illustrated in Figure 15, a rubber belt conveyor 12(a)
having a pair of belts carries the inspection carrier 10
from the package carrier loading area 1l (illustrated in
Figure 3) to the deionized water dosing station 16. A
pneumatic stop 170 having a pawl I71 is used to hold a
series of inspection carriers ~0 upstream of the dosing
station 16. When a new inspection carrier 10 is to be
loaded, the pneumatic stop mechanism I70 retracts pawl
171, allowing the inspection carrier 10 to be carried
into the dosing station on conveyor 12(a). A separate
set of jaws mounted on a pneumatic locking mechanism 172
(illustrated in Figure 1) engage the inspection pallet
10 and hold it:securely in position for package dosing.
A plurality of dosing nozzles I74 are mounted on a
horizontal reciprocating beam support member 176 and are
connected to the F.M.I. pumps 140 by virtue of a
plurality of tubing members 178 with a separate pump for
each nozzle. Each of the nozzle members 174 terminates
3n a sixteen gauge teflon needle~ha«ing an ID of .045
-
CA 02534044 1995-06-08
-22-
inches -.048 inches which is suspended directly above
1 the package carriers 20, and more particularly, above
the bowl member 36. In operation, a pneumatic cylinder
180 which is fixably secured to support frames 181 and
182 reciprocates carriage member 164, vertical supports
185,186 and the horizontal mounting beam 176 to enable
the teflon needle tips to be lowered into the recessed
bowl 36 of the package carriers 20. The tips are
reciprocated downwardly, and approximately 600
microliters of degassed and deionized water is injected
therethrough to partially fill the bowl 36. After the
bowls are filled with the desired dosage, pneumatic
cylinder 180 is actuated and the reciprocal support beam
I76 is raised to lift the teflon needles free of the
package carriers 20.. The use of a reciprocating dosing
needle eliminates agitation or splashing in the dosing
of the degassed and deionized water. Undue agitation or
splashing may also lead to the enlargement of air and
the formation of air bubbles which may generate a false
negative inspection signal. The inspection carrier 10
is then advanced out of the dosing station 16 to the end
of conveyor 12(a) where it engages a push conveyor 17,
driven by a servo motor, which pushes the inspection
carrier 10 across s stainless steel platform 190 to the
lens loading area 18. The lens loading area 18 is
specifically designed to accommodate two inspection
pallets 10 and provide a ganged array of thirty-two
package carriers for receipt of thirty-two individual
contact lenses.- When these two inspection pallets 10
are in the lens transfer position 18, tapered pins (not
3~ shown) engage registration cavities on the pallets (2
per pallet) and provide precise positioning during lens
transfer.
While 2 X 8 and 4 X 8 arrays have been utilized in
the post-hydration processing section of the present
CA 02534044 1995-06-08
-23-
invention, it is understood that a variety of array
1 configurations could be utilized in the practice of the
present invention.
The 4 X 6 array of the hydration carrier 860 is
different than the 4 X 8 array of package carriers in
the lens loading area 18. The second 4 X B array 102
mounted on robotic transfer means 100 is adjustable to
- accommodate the first 4 X 8 array in the second
hydration carrier 860 which has 30 mm centers between
lenses, and the "bubble blow off" station 70, and.then
expands to 30 X 50 mm centers, which is the dimension of
the third 4 X 8 array at the lens loading area 18 as
will be hereinafter described with respect to Figures 8
and 9.
As illustrated in Figures 8 and 9, the 4 X 8 array
102 is illustrated in an expanded configuration in
Figure 8, and a collapsed configuration in Figure 9.
The array lOZ includes thirty-two convex lens carrier
elements 104 as previously described with respect to
Figures 6 and 7. Along the center line~of thewarray are
~ four fluid coupling members 864 which engage conduits
863 on the second hydration carriers 860. The array is
made of four separate lines or elements 190-193, each of
which carries eight convex carriers 104. Each of the
linear members 190-193 is mounted for reciprocation
along internal guide rods 194 and 195 as more fully
illustrated in Figure B. A pneumatic chuck 196,197 is
positioned on either side of the array, and upon
actuation draws the outer most elements 190,193
outwardly as illustrated in Figure 8 along the guide
rods 194,195. Each of the outer most arrays 190,193
also carries a pair of internal sliding stops, one of
.which is illustrated in Figure B at 198 which draw the
inner most linear elements 191 and 192 outwardly, with
linear element~90 drawing linear 191, and linear
CA 02534044 1995-06-08
-Z4-
element I93 drawing linear element 192. Compression
1 springs 199 also assist in separating the linear
elements of the array.
It should also be noted that the array 102 is
rotatable about turntable 103 to provide for the proper
orientation of the array when transferring lenses from
the hydration station to the lens loading area. The
robotic transfer device 100 also includes first and
second articulated arms 107,109 and a vertical arm 105
having a reciprocal servo motor 106 (see Figure 2j
1p mounted therein which enables complete three dimensional
movement of the 4 X 8 array between each of the various
transfer points which the robotic transfer device
serves. As illustrated in Figure ~, the weight of the
102 is substantially offset by a preload spring 108
which carries much of the weight of arm I05 and array
102, thereby reducing the load on_vertical servo motor
106.
Each of the convex lens carrier elements 104 also
includes an interior conduit 110 terminating in at least
one port 111 which may be used to ir.;..:aduce a_ fluid _ _.
between the convex lens carrier element and the contact
lens 8. When the array 102 is positioned over the
plurality of lens carrier elements at the lens loading
area I8, the array elements 191-193 are spread to align
each of the convex lens carrier elements 104 with an
associated package carrier immediately therebelow, and a
'small amount, nominally 300 N1,_of degassed and
deionized water is pumped by precision dosing pumps 140
through conduit 110 to transfer the contact lens 8 from
the convex carrier 104 to the bowl 36 of the package
carrier 20. Again, the use of degassed deionized water
enables transfer of the lens without risking the
development of small air bubbles from dissolved gasses
_ in the deionized water that might otherwise "seed" on
-~
CA 02534044 1995-06-08
--25~-
the contact lens 8. After the lenses 8 have been transferred
to the package carrier 20, the 4×8 array 102 is
collapsed by actuating air chucks 196,197, to return the array
to a configuration that matches the configuration of the
hydration carrier 860.
When both pair of inspection carriers 10 have been
loaded at the lens loading area 18, a second servo motor
actuated push arm 18(a) transfers both pallets from the lens
loading area to a staging area 19(a) as illustrated in FIG. 1.
At staging area 19(a), an overhead double axis transport
carrier 21 singulates one of the inspection carriers and picks
up a single pallet 10 for transfer to the automatic lens
inspection station 15 as illustrated in FIGS. 1 and 3. The
overhead transport 21 is a double axis transport mechanism,
and is used to isolate the automatic lens inspection system 15
from the remainder of the post-hydration line. By utilizing a
double axis transport mechanism, the pallet 10 can be gently
conveyed to the automatic lens inspection system, and thereby
avoid any vibration that might otherwise impair the inspection
results. After the first pallet l0 has been lifted from the
staging area 19(a), a push arm 19 moves the remaining pallet
10 (b) into the staging area 19 (a) for transfer by the double
axis transport mechanism 21 to the Automatic Lens Inspection
System 15, as illustrated in FIGS. 2 and 3.
In the Automatic Lens Inspection System illustrated in
FIG. 3, as the inspection carriers are conveyed through the
system by conveyors 15(b) a light beam or pulse is directed
from sources 15(c) and through a lens to be directed and
focused on a screen (not shown) to produce an image of the
lens therebelow. Preferably, the screen includes an array of
pixels, each of which generates a respective one electric
signal proportional to, or representing, the intensity of the
light incident
CA 02534044 1995-06-08
-26-
on the pixel. Those electric signals are then processed
to determine if the lens is acceptable for consumer use.
Any suitable procedure may be used to process or analyze
the electric signals from the pixel array; and, for
instance, suitable procedures are disclosed in copending
Patent Application Nos. 993,756 and 995,281, entitled
"Automatic Lens Inspection System". As illustrated in
Figures 3, separate systems are utilized to inspect the
sixteen lenses carried in inspection carrier 10. After
completing the test for the last bank of lenses, the
Automatic Lens Inspection System sends a datablock with
the vision inspection results to the programmable logic
controller. used to consolidate the lenses for packaging.
After the lenses have been inspected by the
automatic lens inspection system 15, the inspection
pallet is lifted by the second double axis overhead
transport 22 and placed on conveyor 12(b) for transport to
the deionized water removal station 24. The deionized
water is removed by a specially configured nozzle, as
described in EP 0 618 063, entitled "Solution Removal
Nozzle". As described earlier, the deionized water is
used to center the lens within the package carrier during
the inspection process, but is removed prior to packaging,
to enable a precise dosing of a buffered saline solution
in the final package, as will hereinafter be described in
detail.
After removal of the deionized water, the lenses,
package carriers and inspection pallet are transported to
the package removal pick point 25 which clamps the
inspection pallet 10 to enable a second robotic transfer
CA 02534044 1995-06-08
-27-
device 200 to remove the package carriers and lenses
1 therefrom.
THE CONSOLIDATION BUFFER
As illustrated in Figure 2, 3 and 16, the
second robotic transfer device 200 is positioned
adjacent conveyors 12, 13 and has mounted thereon a
2 X 8 array 202 of sixteen independently actuable vacuum
gripping means. Inspection pallet 10(b) is conveyed.
along conveyor 12 to a predetermined product pick point
25, as illustrated in Figure 3 and the 2 X 8 array 202
~is positioned thereabove to remove each of the sixteen
., products from the inspection carrier 10(b), immediately
following the removal of the deionized water as
previously described with respect to Figure 3.
In the practice of the present invention, a
.. programmable logic controller is used to control the
various elements of the present invention and receives a
vision datablock from the automated inspection system
having a flag set for each of the products in inspection
carrier 10(b) that is out of product specification.
After the products 20 have been removed from. the
inspection carrier 10(b), the robotic transfer device
200 positions the 2 X B array over conveyor belt 14 and
selectively discharges the ouc of spec products. Those
products are then removed by conveyor 14 for subsequent
destruction or.recycling.
The robotic device 200 then. places the remaining
products on a vacuum consolidation buffer 230 as
~ indicated at 230(c). The vacuum consolidation buffer of
the present invention will~be described with respect to
Figures 16 - 19 in which 230(a),(b) diagrammatically
represent a pair of elongated vacuum rails defined by
housing members 231(a),(b) which enclose vacuum plenums ,
CA 02534044 1995-06-08
-28-
242(a),(b) and which define a plurality of vacuum slits
1 244(a),(b).
The product array as deposited at 230(c) includes
gaps or random variations in the product flow resulting
from the.removal of the defective products from the
serial product flow. The vacuum consolidation buffer
230 includes a pair of pneumatic product followers
232,234 which are used to consolidate the product group
230(c) with the other already consolidated products on
consolidation rail 230.
Each of the pneumatic followers 232,234 is
independently advanced in the direction of arrow C until
each product stream is consolidated, thereby eliminating
gaps or voids in the product stream which result from
the inspection and rejection of defective products. For
example, as product 20(f) encounters product 20(g), the
entire stream of product driven by product follower 232
will advance and trigger an optical sensor 236, which
generates a control signal for the programmable logic
controller to de-energize product follower 232 and
return the follower to the initial start position,.
Likewise, optical sensor 238 generates a similar return
signal for product follower 234 when the second product
stream has been consolidated. After consolidation of
the product, a separate indexing mechanism 240 returns
both product streams in the direction of arrow D to a
predetermined registration point for subsequent robotic
handling. In the present invention, the consolidation
buffer 230 includes a pair of vacuum rails 230(a),230(b)
which lightly grip the product to permit sliding
movement of the product along the rails in response to
product followers 232,234, but which will prevent
"shingling" or overlapping of adjacent edges of product
packages which might otherwise occur during
consolidation.
CA 02534044 1995-06-08
-29-
As illustrated in Figure 18 and 19, the product
1 followers 232,234 are mounted on pneumatically driven
carriages, one of which is visible in elevation view of
Figure 18 and two of which are visible in plan view in
Figure 19. The carriage includes a rodless cylinder 250
mounted for reciprocation on pneumatic cylinder 252 and
guided by guide rod 251. The product followers 232,234
are each mounted to the respective carriages by virtue
of a pair of parallel rods 254(a),(b),254(c),(d) whfch
are mounted for reciprocation within housings
250(a),(b).
The product string is advanced in the direction of
arrow C until they trigger one or both of the optical
sensors 236,238. When the optical sensors are
triggered, the programmable logic controller reverses
the pneumatic bias on rodless cylinder 252 and the
carriage 250 is then retracted to its original position
as illustrated in Figure 18. In addition, a proximity
sensor (not shown) at the end of the stroke will also
generate a signal to reverse the direction of carriage
~ 250 if no product has been deposited on either of the
consolidation buffer rail 230(a),(b).
After the respective product streams have been
advanced from position 230(c) to actuate the optical
sensor 238, a product indexing mechanism 24U is actuated
to return the product string to a predetermined location
for registration with the third robotic transfer device
300 which transfers product onto the packaging indexing
table 400. The product indexing mechanism 240 includes
a pneumatic cylinder 264 which actuates a push rod 266
and a pusher plate 262 into engagement with the product
stream on the vacuum consolidation rails. The product
pusher arm 262 then returns the leading edge of the
first.package carrier on each vacuum rail to a
predetermined index position for registration with the
'
CA 02534044 1995-06-08
-30-
2 X 5 array 302 mounted on the packaging robotic
1 transfer device 300.
PACKAGING TRANSFER
A package feed robotic handling device 300 is
positioned between the consolidation buffer 230 and a
packaging station 400, and is equipped with an array 302
which contains ten vacuum gripping means arranged in a
2 X 5 matrix. The 2 X 5 array 302 is first positioned
over product group 20(d) and the vacuum gripping means
is actuated to withdraw the first ten products from the
vacuum consolidation buffer 230. The packaging robotic
handling device 300 then positions the 2 X 5 array and
product group 20(d) over position 1 on the packaging
indexing table 400, and drops the array of products onto
support pallet 4I0 mounted on the packaging indexing
table 400.
During packaging, the package indexing turntable
400 rotates support pallets 410 from position to
position to enable the products to undergo subsequent
packaging steps. In the event there is a malfunction or
delay in the operation of the package indexing turntable
400, the incoming product arriving on consolidation
buffer 230 may be temporarily stored in a buffer area
308 which has a plurality of buffer pallets 310
positioned therein. When the packaging index table 400
resumes operation, the package robotic handling device
300 will then transfer products in the 2 R 5 arrays from
the buffer pallets 310 to the support pallets 410 on a
first-in, first-out basis.
If the product being handled is time sensitive, the
programmable logic controller can generate a time stamp
to be placed with each product array as it is
transferred from any given processing station to any
CA 02534044 1995-06-08
-31-
subsequent processing station. Thus, a time stamp may
1 be placed on the product when inspected, or when
transferred to the buffer area 308. If the product is
transferred to buffer 308, the X,Y coordinates of the
array are also stored with the time, stamp. If the time
sensitive allotment expires before packaging index table
400 has resumed operation, the packaging robotic
handling device 300 will then discard expired time
sensitive product, and will transfer only product
meeting the time sensitive criteria to the support
pallet 4I0. Likewise, if a problem in the production
line results in an inordinate number of products being
rejected, so that less than five products are available
on either consolidation string 230(a),(b) at position
20(d) then the robotic handling device 200 will transfer
product as necessary to balance product streams on both
sides of the packaging consolidation buffer 230, and
thereby enable removal of product as a 2 X 5 product
array. Buffer area 308 will accommodate approximately
fifty pallets for intermediate_storage, or approximately
10 minutes of product stream in the event the packaging
operation is temporarily interrupted for resupply,
maintenance or adjustments.
PACKAGING
After the 2 X 5 array of package carriers has been
deposited on support pallet 410, the pallet is rotated
to position 412 where optical sensors verify that a
package has been loaded at each position and that the
packages are correctly aligned on the pallet. Indexing
turntable 400 is then rotated again to station 414
wherein.each of the individual package carriers are
dosed with approximately 950 microliter of a saline
solution.
CA 02534044 1995-06-08
-32-
Station 414 is illustrated in elevation view in
1 Figure 20, wherein five dosing nozzles 415 are
positioned above five package carriers 20. Dosing
nozzles 415 are mounted on a cantilever support arm 450
to thereby suspend the nozzle over the rotating table
400. A plurality of saline tubes 417 carry a buffered
saline solution, from a plurality of precision dosing
pumps, similar to the F.M.I. pumps used to pump the
' deionized water to dosing station 16 depicted in Figures
1 and 3.
The use of deionized water in the hydration and
inspection steps significantly speeds the production
line as a whole since the time consuming ionic
neutralization of the polymer from which the lenses are
made does not occur until after the inspection process.
When deionized water is used for hydration and
inspection, the final step of the process is to
introduce buffered saline solution into the final
package with the lens and then seal the lens within the
package so that_final lens.equilibration (ionic
neutralization, final hydration and final lens
dimensioning) is accomplished in the package at room
temperature or during sterilization after the lens has
been packaged and sealed.
It has been determined empirically that it is
desirable that soft contact lenses produced in
accordance with the present invention be exposed to
atmosphere for no more than sixty minutes between the
removal of the deionized water at station 24
(illustrated in Figure 3) and the dosing of the saline
solution at station 414 in Figure 5. The programmable
logic controller which previously received the
inspection results from the automated lens inspection
system and correlated those results to the individual
lenses, also time stamps the individual lenses at the
CA 02534044 1995-06-08
-33-
pick up point Z5, immediately following the removal of
the deionized water at station 24. This time stamp is
transferred through consolidation and into the 2 X 5
array When removed by the packaging robotic transfer
device 300. In the event the indexing turntable 400 is
not operational, and the 2 X 5 array is stored in the
buffer 308, then the X,Y coordinates of the 2 X 5 array
are stored with the time stamp to enable the packaging
robotic transfer device 300~to select "fresh" product,
e.g. less than sixty minutes old, at the time the
packaging dial 400 resumes operation. After operation is
resumed, the robotic transfer device 300 will then
dispose of the "expired" product, rather than
transferring it to the packaging dial.
After saline dosing at station 414, the saline
level is checked at station 415 and the support pallet is
then rotated under a final product check station 416 to a
foil receiving station 418.
As described earlier, each group of 5 package
carriers 20 receives a single laminated foil cover sheet
which is heat sealed to the package carriers. The lens
package is more fully described in U.S.S.N. 995,607,
entitled "Packaging Arrangement for Contact Lenses", also
assigned to the assignee of the present invention.
The laminated foil stock 432 is fed from a large
indefinite spool through a tensioning device 434 to an ink
jet printer 436 which prints the lot, batch and power
number of the lenses to be packaged. The foil laminate is
cut from an indefinite length product into two strips
that are heat sealed to the 2 X 5 product array to
provide two separate 1 X 5 product strips. The foil in
between each of the package carriers is also
CA 02534044 1995-06-08
-34-
partially severed, scored or perforated to enable the
consumer to separate individual packages from the
1 X 5 array at the time the product is used. The
partial scoring is done with a series of rolling blades
440(x)-(d) which are pneumatically biased into a drum
439. The foil is then split into two strips by a foil
slitter blade 441 and the foil passes through a
stationary gripper and sensing mechanism 442. A video
camera 438 and a series of sensors at station 442 are
used to provide precise alignment of the information
printed by the ink jet printer 436, with the printing
fields into which said printing is placed, and the
alignment of the perforations or scores provided by
rolling blades 439. An advancing grfpper 434 is
provided to draw a length of foil laminate corresponding
to the 1 X 5 array and sever the strips with a rotating
knife 444. At. the completion of this cut, the advancing
gripper 434 has adv~~~ed in the direction of arrow E in
Figure 4 to place the 1 X 5 foil strips under vacuum
gripping heads 418(a),.(b). These vacuum gripping heads
~ then reciprocate downwardly to grip the foil, lift ft
from the advancing and cutting station 434, and transfer
the foil to the package indexing turntable 400 at the
foil placement station 418.
The package indexing turntable 400 is then rotated
again, and a heat seal mechanism 420 seals a single
strip of foil to five separate package carriers in a
single high temperature short cycle sealing operation.
As illustrated in Figures 21 and 22, the foil
strips are heat sealed to the two 1 X 5 arrays of
3~ package carriers 20. A heated seal head 510, heated by
a plurality of electric heaters 512 (two of which are
illustrated in the embodiment of Figure 22) mounted in a
heating plate 514. The heating plate 514 is secured to
the back of the seal head 510, and is supported by a
-' 35
CA 02534044 1995-06-08
-35-
pneumatic cylinder or press 5I6 which presses the heated
1 seal head 510 against the laminar foil sheet on the
package carriers 20, which are supported by the pallet
410 such that the foil laminate and package carrier
flanges are squeezed between the heated seal head and
the pallet 410 as supported by the index turntable. The
heated seal head fs electrically heated, and the
temperature thereof is measured by thermocouples 518 on
each side of the seal head 510 to maintain the
temperature at a high temperature, when compared to
similar prior art arrangements. The temperature is
maintained in a range from 210°-265°C, preferably at
258°C.
The heated seal head comprises a 2 x 5 array of
cylindrical sealing elements 520, each of which secures
one of the foil laminar sheets to each group of package
carriers 20 with an annular seal 39 around the cavity 36
in the package carrier 20. The pneumatic cylinder is
coupled to the heated seal head by a mount jack bolt 522
and cylindrical support struts 524. The support struts
524 are biased upwardly by springs 526, such that the
heated seal head is raised and normally biased to the
upper position illustrated in Figure 21, unless the
pneumatic cylinder 516 forces it down for a sealing
operation.
In operation, the back force generated,by the
pneumatic cylinder is measured by an in-line load cell
528, and a solid state timer is initiated when a force
is reached of approximately 2700 newtons, which is
approximately 95; of the peak force of approximately
3600 newtons. The solid state timer times a relatively
short time period of approximately 0.4 to 0.48 seconds,
after which the pressure in the pneumatic cylinder 516
is released. This approach, when compared with similar
prior art approaches, is very hot, very hard and very
'
CA 02534044 1995-06-08
-36-
short, which creates a seal which is both detachable and
1 customer friendly.
The package indexing turntable 400 is preferably
reinforced under the seventh angular position to
withstand the heat sealing forces imparted thereto by
the pneumatic cylinder 516. The indexing turntable 400
must be maintained in a substantially level position for
the operations described herein. The pneumatic cylinder
516 at the seventh position applies a substantial force
to the indexing turntable, and accordingly to maintain
the turntable level, an approximately 2~ x 3~ inch
support block 530 of a durable plastic material, similar
to Teflon~, is placed on top a central support 532 and
surrounding supports 534 positioned beneath the
pneumatic press. The support block 530 is in constant
contact with the indexing turntable 400 to ensure that
the deflection of the indexing turntable 400 under the
. pneumatic cylinder 516 is minimal. Alternatively, a
pneumatically actuable movable support could be
positioned in contact with the bottom of the indexing
~ turntable prior to operation of the pneumatic cylinder
driving the heated seal head, and be repositioned out of
contact with the bottom of the table after operation of
the pneumatic cylinder.
The package indexing turntable 400 is then rotated
to position 422 where a reciprocating transfer head 446
removes the sealed product from the indexing turntable
400 and transports it in the direction of arrow F for
steriliaation'and cartoning.
while the invention has been particularly shown and
described with respect to the preferred embodiments
3~ thereof, it will be understood by those skilled in the
art that the foregoing, and other changes in form and
details, may be made therein without departing from the
CA 02534044 1995-06-08
-37-
spirit and scope of the invention, which is limited only
1 by the scope of the following claims.
to
20
30
