Information
-
Patent Grant
-
6497000
-
Patent Number
6,497,000
-
Date Filed
Thursday, September 30, 199924 years ago
-
Date Issued
Tuesday, December 24, 200221 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Meece; R. Scott
- Zhou; Jian S.
- Gearhart; Richard I.
-
CPC
-
US Classifications
Field of Search
US
- 015 304
- 015 3092
- 015 310
- 015 3161
-
International Classifications
-
Abstract
The present invention discloses an apparatus for cleaning ophthalmic devices. The apparatus has a conveying system for transporting lens mold carriers to a cleaning station. The cleaning station has at least one movable cleaning assembly which is situated above the lens mold carrier and has a recess. When the cleaning assembly is lowered to the lens mold carrier, a substantially enclosed or enclosed cavity containing the lens mold is created by the carrier and the recess of the cleaning assembly. Compressed gas is injected into the cavity to dislodge any debris that may be present on the lens molds, and a vacuum is employed to remove gas and debris from the cavity.
Description
FIELD OF THE INVENTION
The invention relates to an apparatus for use in manufacturing ophthalmic components such as contact lenses, and more particularly, to an apparatus for cleaning the molds used to form contact lenses.
The manufacture of ophthalmic components, for example contact lenses, is typically carried out in a large number of separate production steps. Very often these production steps must be carried out in an ultra-clean (i.e., inert and sterile) environment such as a “clean room”. Each production step, for example the manufacture and transfer of intermediate components, the positioning of equipment, such as molds, or the operation of equipment, presents an opportunity for contamination of the ophthalmic component. The danger for contamination is especially acute in the manufacture of contact lenses. If the lens manufacturing process is contaminated or corrupted in any way, in most cases the finished lens must be discarded.
Contact lenses are generally manufactured in automated or semi-automated production processes. Lens molds consisting of base curve (convex) and front curve (concave) mold halves are transported on carriers through the production process. The molds are symmetrical and are fitted together to form a small crescent shaped mold cavity between the base curve and front curve molds. A lens is formed by introducing a monomer in the front curve mold and then sandwiching the monomer between the base curve and front curve molds. The monomer is then polymerized through heat treatment, light treatment or other polymerizing process, thus forming a lens. The lens is then removed from the molds for further treatment and is packaged for consumer use.
If either the base curve or front curve mold is contaminated in any way, the lens formed will contain a flaw, such as an uneven face, and will most likely have to be discarded. Therefore, great care is taken to clean the base curve and front curve molds prior to introducing the monomer to the front curve mold. Currently, the cleaning of the base curve and front curve molds is accomplished manually. Using a hand held compressed gas (i.e. nitrogen) gun, compressed gas is blown over the mold halves to remove any debris that may be present on the surface of the molds.
Manual cleaning is an inefficient method by which to clean equipment used in the manufacture of ophthalmic components, especially contact lens molds. Given that the majority of the manufacturing steps involved in the production of contact lenses are automated, the use of any manual cleaning method has the potential to damage equipment, reduce the quality of finished product or at a minimum reduce the efficiency of the overall manufacturing process. For example, lens molds typically travel through the contact lens manufacturing process on carriers which are designed to hold the molds securely throughout the process. If the lens molds are manually cleaned, they are susceptible to becoming misaligned in their carriers or contaminated through inadvertent human contact. A misaligned mold half could form a misaligned lens mold. Misaligned molds result in flawed contact lenses or in manufacturing downtime to either remove or repair the misaligned mold. Similarly, as a result of fatigue or inattention, a technician could inadvertently permit a contaminated mold to proceed through the contact lens manufacturing process, thus resulting in a defective contact lens that could be sold to consumers.
The need therefore exists for providing an apparatus for use in the manufacture of ophthalmic components, especially contact lenses, that cleans a desired intermediate component or part to prevent contamination of that part, yet overcomes the above-described disadvantages of manual cleaning methods. In particular, the novel apparatus permits the cleaning of contact lens molds to occur automatically, uniformly and concurrently with other manufacturing steps. The apparatus of the present invention allows for continuous operation, and thus makes more extensive automation of the manufacturing operation possible.
OBJECTS OF THE INVENTION
It is an object of this invention to provide an apparatus and method for cleaning ophthalmic devices, especially contact lens molds.
It is a further object of this invention to provide an apparatus to automate the cleaning of ophthalmic devices, especially contact lens molds.
It is a further object of this invention to provide an automated apparatus and method for the cleaning of contact lens molds that increases the efficiency of the contact lens manufacturing process.
SUMMARY OF THE INVENTION
All of the above and other objects are achieved by an apparatus for the cleaning of ophthalmic components, especially contact lens molds. In its simplest form, the apparatus includes an ophthalmic component carrier, a conveying means, such as a conveyor, for transporting the carrier, and a cleaning station to receive and clean the ophthalmic devices. The cleaning station includes at least one cleaning assembly that is mechanically lowered onto the top of the lens mold carrier. There are recesses formed in the cleaning assembly such that when the cleaning assembly is lowered the recesses and the carrier define a substantially enclosed cavity in which a lens mold is housed. compressed gas is then injected into the cavity to dislodge any debris that may be on the lens mold. The cavity is subjected to a vacuum to remove any debris that may be present.
In a preferred embodiment, the apparatus includes at least one front curve lens mold carrier and at least one base curve lens mold carrier. The front curve lens mold carrier includes a front curve top plate and a front curve bottom plate attached to the top plate. The front curve bottom plate has a plurality of holes and receiving slots formed therein. The receiving slots engage receiving members (e.g. pins) located on the base curve mold to stabilize the mold during monomer polymerization. The front curve top plate also has a plurality of holes formed therein. The top plate holes are in axial alignment with the bottom plate holes thereby providing an opening completely through the carrier when the top plate and the bottom plate are connected to each other. The top plate hole is separated into two sections by a flange. A hollow piston, guided by the flange, travels up and down in the two sections of the top plate hole. The piston is supported by a spring housed in the second section of the top plate hole which rests upon the top surface of the bottom plate. The top plate also has two. top plate receiving slots in axial alignment with the bottom plate receiving slots.
The preferred embodiment of the apparatus further includes at least one base curve lens mold carrier. The base curve lens mold carrier also has a plurality of holes formed therein. The holes formed in the base curve lens mold carrier are divided into a first (or top) section and a second (or bottom) section with the first section being larger in diameter than the second section. The base curve lens mold carrier also has a channel extending from the edge of the first section to the edge of the carrier which provides rotational alignment for the molds by engaging with a protrusion on the outer diameter of the mold flange. The base curve lens mold carrier also includes two raised receiving members (e.g. pins) which are in axial alignment with the receiving slots formed in the front curve lens mold carrier and which engage with the receiving slots to form a stable mold for manufacturing a contact lens. Preferably, the carriers are transported to the cleaning station on a conventional conveyor.
The cleaning station which receives the front curve and base curve lens mold carriers is essentially table-like and includes at least two cleaning assemblies suspended from the underside of the table that can be lowered onto the top of the lens mold carriers. Preferably, the cleaning station consists of four legs and two parallel cross support members attached to the upper portion of the legs. A mounting plate (the table top) is movably attached to both cross support members in a manner that allows the mounting plate to move (i.e. slide) in relation to the cross support members. At least two means for providing vertical movement, such as pneumatic cylinders, are attached to the bottom surface of the mounting plate. At least two connectors for connecting the lens mold cleaning assemblies to the pneumatic cylinders are attached to the bottom of the pneumatic cylinders.
At least one front curve lens mold cleaning assembly and one base curve lens mold cleaning assembly are attached to the connectors. Each of the cleaning assemblies includes a top plate, a middle plate, and a bottom plate. The bottom plate of each assembly has a number of-recesses corresponding to the number of lens molds carried on the lens mold carrier. The bottom plate recesses are also formed such that they can be in axial alignment with the holes of each carrier.
Each of the top, middle and bottom plates has a plurality of holes and recesses arranged to form two channels of fluid communication through the cleaning assembly. In operation, the first channel allows compressed gas to flow through the assembly to be injected into the recesses formed in the bottom plate. The injected gas dislodges any debris that may be present on the lens molds. The second channel of fluid communication allows an external vacuum source to pull the gas and debris out of the recesses.
After the front curve and base curve lens molds are cleaned, the cleaning assemblies retract and the conveyor carries the lens. mold carriers to subsequent stations in the contact lens manufacturing process.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a perspective view of a preferred embodiment of an apparatus for use in manufacturing ophthalmic components according to the invention;
FIG. 2
is a top view of a front curve lens mold carrier;
FIG. 3
is a cross-section of the front curve lens mold carrier of
FIG. 2
taken along line
3
—
3
;
FIG. 4
is a top view of a base curve lens mold carrier;
FIG. 5
is cross-section of the base curve lens mold carrier of
FIG. 4
taken along line
4
—
4
;
FIG. 6
is an elevation view of the apparatus of
FIG. 1
showing the cleaning assemblies positioned over the lens mold carriers;
FIG. 7
is an elevation view showing how the front curve lens mold carrier and the base curve lens mold carrier join to form completed lens molds;
FIG. 8
is a top view of the apparatus of
FIG. 1
showing the mounting plate moved to the side;
FIG. 9
is an end view of the apparatus of
FIG. 1
showing the cleaning assemblies positioned over the lens mold carriers with a portion of a cross support member removed for clarity;
FIG. 10
is a top view of a front curve mold cleaning assembly according to the invention;
FIG. 11
is a cross-section of the front curve mold cleaning assembly of
FIG. 10
taken along line
11
—
11
;
FIG. 12
is a cross-section of the front curve mold cleaning assembly of
FIG. 10
taken along line
12
—
12
;
FIG. 13
is a top view of a front curve mold cleaning assembly top plate;
FIG. 14
is a cross-section of. the front curve mold cleaning assembly top plate of
FIG. 13
taken along line
14
—
14
;
FIG. 15
is a cross-section of the front curve mold cleaning assembly top plate of
FIG. 13
taken along line
15
—
15
;
FIG. 16
is top view of a front curve mold cleaning assembly middle plate;
FIG. 17
is a cross-section of the front curve mold cleaning assembly middle plate of
FIG. 16
taken along line
17
—
17
;
FIG. 18
is a detailed view of the front curve mold cleaning assembly of
FIG. 11
showing channels of fluid communication;
FIG. 19
is a top view of a front curve cleaning mold assembly bottom plate;
FIG. 20
is a cross-section of the front curve mold cleaning assembly bottom plate of
FIG. 19
taken along line
20
—
20
;
FIG. 21
is a cross-section of the front curve mold cleaning assembly bottom plate of
FIG. 19
taken along line
21
—
21
;
FIG. 22
is a top view of a base curve mold cleaning assembly according to the invention;
FIG. 23
is a cross-section of the base curve mold cleaning assembly of
FIG. 22
taken along line
23
—
23
;
FIG. 24
is a cross-section of the base curve mold cleaning assembly of
FIG. 22
taken along line
24
—
24
;
FIG. 25
is a top view of a base curve mold cleaning assembly top plate;
FIG. 26
is a cross-section of the base curve mold cleaning assembly top plate of
FIG. 25
taken along line
26
—
26
;
FIG. 27
is a cross-section of the base curve mold cleaning assembly top plate of
FIG. 25
taken along line
27
—
27
;
FIG. 28
is a top view of a base curve mold cleaning assembly middle plate;
FIG. 29
is a cross-section of the base curve mold cleaning assembly middle plate of
FIG. 28
taken along line
29
—
29
;
FIG. 30
is a top view of a base curve mold cleaning assembly bottom plate;
FIG. 31
is a cross-section of the base curve mold cleaning assembly bottom plate of
FIG. 30
taken along line
31
—
31
;
FIG. 32
is a cross-section of the base curve mold cleaning assembly bottom plate of
FIG. 30
taken along line
32
—
32
;
FIG. 33
is a detailed view of the base curve mold cleaning assembly of
FIG. 23
showing channels of fluid communication.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following description, like reference numerals designate like or corresponding parts throughout the several figures. It is to be also understood that such terms as “front”, “rear”, “side”, “up”, and “down” are used for purposes of locating one element relative to another and are not to be construed as limiting terms. Further, it should be understood that the illustrations are for the purpose of describing preferred embodiments of the invention, and thus are not intended to limit the invention in any manner.
Referring now to the drawings,
FIG. 1
, is a perspective view of an apparatus, indicated generally at
10
, for use in the manufacture of ophthalmic components, especially contact lenses. In particular, the apparatus
10
is a cleaning device designed to provide automated cleaning of contact lens molds. Contact lens molds typically have two parts: a front curve lens mold
12
and a base curve lens mold
14
. FIG.
7
. To manufacture a contact lens a polymerizable lens formulation is placed into the front curve lens mold. The base curve mold is then placed in contact with the front curve mold and the polymerizable formulation is allowed to polymerize.
The cleaning device
10
has a front curve lens mold carrier
16
, a base curve lens mold carrier
18
, a means for conveying the lens mold carriers
20
, and a cleaning station
22
. Preferably, the cleaning device
10
is designed such that it is capable of cleaning multiple front and base curve lens molds simultaneously. While the embodiment shown in the figures is designed to clean 16 front curve lens molds (2 sets of 8) and 16 base curve lens molds (2 sets of 8) it should be understood that the invention could be easily modified to create a device designed to clean any multiple of front or base lens molds. Similarly, the invention could easily be modified to clean lens molds arranged in circular carriers rather than in the rectangular carriers shown in the figures. The particular embodiment shown in the figures should not be viewed as limiting the scope of the invention or the claims.
Overview
Referring now to FIG.
1
and
FIG. 6
, two front curve lens mold carriers
16
, each holding eight front curve lens molds, and two base curve lens mold carriers
18
, each holding eight lens molds, are transported to a cleaning station
22
, by a conveying means
20
. At cleaning station
22
the lens mold carriers are positioned under lens mold cleaning assemblies
24
and
26
. Cleaning assemblies
24
and
26
are lowered and placed in close proximity to the lens molds which are carried by lens mold carriers
16
and
18
. Compressed gas is then blown onto the lens molds to dislodge any debris that may be present, and vacuum is applied to remove any debris. The cleaning assemblies are then retracted and the lens mold carriers proceed to the polymer injection station. The apparatus and process will be discussed in greater detail below.
Front Curve Lens Mold Carriers
A front curve lens mold carrier (“front curve carrier”) is shown in FIG.
2
and FIG.
3
. The front curve carrier
16
, consists of two plates; a top plate
28
, and a bottom plate
30
which are fixedly attached. Bottom plate
30
contains a plurality of holes
32
, which provide fluid communication through bottom plate
30
. Bottom plate
30
also contains two receiving slots
34
.
Top plate
28
having a top and bottom surface, contains a plurality of holes
36
, which provide fluid communication through the top plate
28
. Top plate holes
36
, are in axial alignment with bottom plate holes
32
thereby providing fluid communication through top plate
28
and bottom plate
30
. Top plate holes
36
, have a top (or first) section
38
, having a first outer diameter and a bottom (or second) section
40
, having a second outer diameter smaller than the first outer diameter separated by flange
42
. A channel
44
, extends from first section
38
to the outer perimeter of top plate
28
. Bottom (or second) section
40
, of hole
36
is situated beneath flange
42
and abuts hole
32
thereby creating fluid communication through front curve carrier
16
. The outer diameter of hole
32
is smaller than the outer diameter of bottom (or second) section
40
thereby creating a ledge
46
at the junction of hole
32
and second section
40
. Top plate
28
also contains two receiving slots
34
that are in axial alignment with bottom plate receiving slots
34
.
Spring
48
is situated within bottom (or second) section
40
and rests upon ledge
46
. A hollow piston
50
, is situated in the path of travel created by flange
42
. Piston
50
rests upon spring
48
and has freedom of movement through flange
42
. In the absence of tension exerted upon. the spring, the top of piston
50
rests slightly above the top of flange
42
as shown in FIG.
3
. When front curve lens mold carrier
16
joins with base curve carrier
18
during lens formation,
FIG. 7
, spring
48
creates tension between the front curve mold
12
and the base curve mold
14
.
Front curve carrier
16
and base curve carrier
18
are joined by engaging front curve locking bar
35
,
FIG. 2
, with notch
61
in base curve stabilizing member
60
, FIG.
7
. Front curve locking bar
35
travels in front curve top plate locking bar channel
37
which intersects receiving slots
34
. Locking bar
35
contains a semicircular notch
39
with an arc at least equal to that of receiving slot
34
. When notch
39
is aligned with receiving slot
34
, the front curve assembly is in the “open” position and can receive base curve stabilizing member
60
. When stabilizing members
60
are in place, locking bar
35
is moved along locking bar channel
37
such that notch
39
is no longer in alignment with receiving slot
34
thus locking stabilizing member
60
and base curve mold
18
in place. FIG.
7
. Locking bar
35
may be moved by exerting force on attached pin
33
.
Base Curve Lens Mold Carriers
A base curve lens mold carrier (or base curve carrier) is shown in FIG.
4
. The base curve carrier
18
, is a solid plate having a top and bottom surface. Base curve carrier
18
contains a plurality of holes
52
, which provide fluid communication through base curve carrier
18
. Holes
52
are arranged such that they are in axial alignment with holes
36
when base curve carrier
18
joined with front curve carrier
16
. FIG.
7
.
Base curve carrier holes
52
, have a top (or first) section
54
, having a first outer diameter and a bottom (or second) section
56
having a second outer diameter smaller than said first outer diameter.
FIG. 5. A
channel
58
, extends from first section
54
to the outer perimeter of base curve carrier
18
.
Base curve carrier
18
also has two raised stabilizing members
60
which contain notch
61
. FIG.
7
. Raised stabilizing members.
60
are in axial alignment with the receiving slots
34
on front curve carrier
16
. As discussed previously, raised stabilizing members
60
engage with receiving slots
34
to form a stable mold during injection and polymerization.
Conveying Means
The conveying device or means
20
could be any type of conveyor or conveyor belt. In a preferred embodiment, shown in
FIG. 9
, the conveying means consists of a solid pallet upon which the lens mold carriers are secured and a conveyor which transports the lens molds to cleaning station
22
and on to further processing.
The Cleaning Station
The cleaning station
22
has a frame, at least one lens mold cleaning assembly (front curve or base curve), and a means for positioning the lens mold cleaning assembly over the lens mold carriers. In a preferred embodiment, shown in FIG.
1
and
FIG. 6
, the cleaning station frame comprises four legs
66
placed substantially symmetrically about one point. The legs are spaced apart to form an area between the legs sufficient for a conveyor or other conveying means
20
to pass between and through the legs. Cross support members
68
are attached to the legs
66
and are parallel to one another. A mounting plate
70
is movably attached to the cross support members
68
. When connected, the mounting plate
70
the cross support members
68
and the legs
66
form a frame with a generally table like arrangement.
Cross support members
68
contain grooves
72
which run longitudinally down the length of cross support members
68
allowing the mounting plate
70
to move in a horizontal fashion relative to cross support members
68
. In the preferred embodiment shown in
FIG. 6
, mounting plate
70
is fixedly attached to a bracket and bushing assembly
74
which contains three bushings,
76
. The bracket and bushing assembly
74
is attached to the cross support member
68
such that the bushing
76
fits within groove
72
. In this manner the. mounting plate
70
may move horizontally with respect to cross support members
68
while remaining attached to cross support members
68
. FIG.
8
. Providing horizontal movement for mounting plate
70
allows easy inspection of the device or lens molds in the event non-optimum operation of the cleaning device is observed. For example, horizontal movement of mounting plate
70
allows an operator access to the mold carriers to-reseat misplaced molds as determined by proximity sensors
80
.
At least one securing mechanism
78
is provided to secure the position of the mounting plate
70
with respect to the cross support members
68
. The securing mechanism could be a set screw securing the bracket and bushing assembly
74
to the cross support members
68
or any other securing device. In a preferred embodiment shown in FIG.
1
and
FIG. 6
, the securing mechanism
78
consists of a spring loaded pin that secures mounting plate
70
when pressed down through a hole in cross support member
68
. Proximity sensor
81
is employed to ensure that mounting plate
70
is properly aligned and secured before the cleaning station can be activated.
Means For Positioning Mold Cleaning Assemblies
Referring now to FIG.
6
and
FIG. 8
, attached to the bottom surface of mounting plate
70
are a plurality of means for positioning lens mold cleaning assemblies
82
. In the preferred embodiment shown in FIG.
6
and
FIG. 8
, the means for positioning
82
are four pneumatic cylinders which are attached to a source of compressed gas (not shown). The pneumatic cylinders are arranged substantially symmetrically and attached to the bottom surface of mounting plate
70
. Although the preferred embodiment of the invention utilizes pneumatic cylinders, it is to be understood that any means for providing vertical movement such as hydraulic cylinders, electric motors or mechanical hand cranks may be employed.
Front and Base Curve Cleaning Assemblies
In a preferred embodiment shown in
FIG. 1
,
FIG. 6
, and
FIG. 9
, four cleaning assemblies are shown: two front curve lens mold cleaning assemblies
24
and two base curve lens mold cleaning assemblies
26
. Each cleaning assembly is connected to pneumatic cylinders
82
by means of a connector
84
. Each front curve and base curve cleaning assembly has three joined plates that allow fluid communication through the plates.
Front Curve Cleaning Assembly
Referring now to
FIG. 10
,
FIG. 11
, and
FIG. 12
, the front curve cleaning assembly
24
is formed by a top plate
86
a middle plate,
88
, and a bottom plate
90
. The three plates are of approximately equal outer dimension, said dimension being approximately equal to the outer dimension of front curve carrier
16
. In a preferred embodiment, the three plates are generally rectangular and of such a size to allow at least eight symmetrically arranged lens molds to fit within its dimensions. In another preferred embodiment, the shape of the outer dimensions of the three plates is square and the size of plates allows at least sixteen symmetrically arranged lens molds to fit within its dimensions. In operation, the three plates are fixedly attached to each other, for example, by screws
97
that are placed at the circumferencial edge of the cleaning assembly.
Referring now to
FIG. 13
,
FIG. 14
, and
FIG. 15
, a top plate
86
has a top surface
92
, a bottom surface
94
, gas injection hole
96
and vacuum hole
98
. The top plate
86
is attached to connector
84
, as shown in FIG.
9
. The bottom surface
94
contains a milled recess
100
, and the recess has an outer perimeter generally smaller than and symmetrical with the outer perimeter of said top plate
86
, thereby creating an outer ridge
102
along the. outer perimeter of the plate. The bottom surface
94
also has a cylindrical island
104
, through which vacuum hole
98
passes to form circular ridge
106
. Ridges
102
and
106
contain-channels
108
and
110
respectively, which accommodate O-rings or some other appropriate sealing device. FIG.
12
. The sealing device allows the top plate
86
and the middle plate
88
to be pneumatically sealed.
Gas injection hole
96
establishes fluid communication between front curve top plate top surface
92
and recess
100
. Fluid communication between top surface
92
and bottom surface
94
is established by vacuum hole
98
.
Referring now to
FIG. 11
, FIG.
16
and
FIG. 17
, a front curve middle plate
88
having a top surface
112
and bottom surface
114
is attached to front curve top plate
86
thereby forming a cavity
116
defined by middle plate top surface
112
and the recess
100
of top plate
86
. FIG.
10
and FIG.
18
. O-rings or some other appropriate sealing device seal cavity
116
. Front curve middle plate
88
contains a hole
118
in axial alignment with top plate vacuum hole
98
and of approximately the same diameter as top plate vacuum hole
98
. Hole
118
and vacuum hole
98
provide fluid communication between the top surface of the top plate
92
and the bottom surface of the middle plate
114
.
The front curve middle plate
88
also contains a plurality of orifices
120
providing fluid communication between cavity
116
and middle plate bottom surface
114
. In a preferred embodiment, there are eight orifices
120
which are arranged symmetrically. The orifices
120
preferably contain a nozzle
122
or other means to direct the flow of gas through orifice
120
. FIG.
11
and FIG.
18
. Annular extensions
124
which are in axial alignment with orifices
120
and which have an inner diameter approximately equal to the diameter of orifices
120
extend from the middle plate bottom surface
114
. Nozzle
122
and annular extensions
124
direct the flow of compressed gas to the lens molds. FIG.
18
.
Referring now primarily to
FIG. 19
,
FIG. 20
, and
FIG. 21
, a front curve bottom plate
90
having a top surface
126
and a bottom surface
128
is attached to front curve middle plate
88
. FIG.
11
. The top surface
126
contains a recess
130
having an outer perimeter generally smaller than and symmetrical with the outer perimeter of the bottom plate
90
thereby creating an outer ridge
132
along the outer perimeter of the plate. Ridge
132
contains channel
134
which accommodates an O-ring or other sealing device. FIG.
12
. The sealing device pneumatically seals the bottom plate and the middle plate when the plates are assembled. When front curve bottom plate
90
is attached to front curve middle plate
88
, a cavity
136
as shown in
FIG. 11
, FIG.
12
and
FIG. 18
is created by recess
130
and middle plate bottom surface
114
.
Referring now to
FIG. 18
, front curve bottom plate bottom surface
128
contains a plurality of raised cylindrical portions
138
having an inner diameter and an outer diameter thereby defining a cylindrical ridge
140
and a cylindrical wall of a recess
142
, situated within cylindrical portion
138
. Optionally, a sealing means, especially an elastomeric sealing means, e.g., o-ring, is attached to the cylindrical ridge
140
, especially at the bottom thereof. Recess
142
extends to a point intermediate top surface
126
and bottom surface
128
. In a preferred embodiment, shown in FIG.
20
and
FIG. 21
, there are eight raised cylindrical portions
138
symmetrically arranged and in axial alignment with front curve middle plate orifices
120
.
A second cylindrical recess
144
having a diameter smaller than the diameter of cylindrical recess
142
extends downward from the bottom of recess
130
. Second cylindrical recess
144
is axially aligned with cylindrical recess
142
and is in fluid communication with cavity
136
and cylindrical recess
142
. Second cylindrical recess
144
is of sufficient diameter to allow middle plate annular extension
124
to substantially occupy recess
144
thereby defining an annular space
146
. Annular space
146
maintains fluid communication between cylindrical recess
142
and cavity
136
. FIG.
18
.
Operation of the Front Curve Mold Cleaning Assembly
In operation, the front curve mold cleaning assemblies
24
and front curve lens mold carriers
16
are arranged so that cylindrical recesses
142
are in axial alignment with front curve lens mold carrier top plate holes
36
. The front curve cleaning assembly
24
is lowered by positioning means
82
to place the ridge
140
close to the flange of the lens mold
12
, e.g., approximately {fraction (15/1,000)} of an inch from the base of a front curve lens mold, thereby forming a substantially enclosed area. FIG.
18
. Alternatively, especially when the ridge
140
is equipped with sealing means, the front curve cleaning assembly
24
is lowered to place the sealing means of the ridge
140
on the flange of the lens mold
12
, thereby pneumatically sealing the lens mold
12
and the cylindrical recess
142
.
Two channels of fluid communication into cylindrical recess
142
are present. The first channel includes hole
96
, cavity
116
, orifices
120
, and annular extensions
124
. The first channel allows an inflow of compressed gas at greater than atmospheric pressure from an outside source (not shown) into cylindrical recess
142
to dislodge any debris residing on the lens mold. The desirable flow rate and/or pressure of the gas impinging on the lens mold may be varied depending on, for example, the effectiveness of the system at removing contaminants. Preferably, the gas is supplied to the cleaning assembly at a pressure of about 15 psi to about 25 psi, more preferably about 20 psi. The compressed gas is filtered before it is applied on the mold to ensure that the gas does not introduce external particulate matters. Gases suitable for the invention include nitrogen, carbon dioxide and air, and desirably, the gas is deionized. FIG.
18
. The second channel of fluid communication is under the influence of a vacuum source or any other device that provides an outflow of gas. Preferably, the outflow device applies between about 1.0 inch of Hg and about 2.0 inches of Hg, more preferably about 1.5 inches of Hg, of vacuum force at the vacuum hole
98
of the cleaning assembly. The second channel is used to remove the gas and debris located in recess
142
. Beginning with recess
142
, the gas and any debris present leave recess
142
via annular space
146
and proceed through cavity
136
, through middle plate vacuum hole
118
and out top plate vacuum hole
98
into a vacuum line (not shown). Gas injection and application of the vacuum can occur independently, simultaneously or sequentially and can be of variable duration. For example, the vacuum is applied first and then quickly the pressurized gas is applied to ensure that all the debris located on the lens mold and in the recess
142
is removed through the annular space
146
.
Base Curve Cleaning Apparatus
Referring now to
FIG. 9
,
FIG. 22
,
FIG. 23
, and
FIG. 24
, the base curve cleaning assembly
26
is formed by a top plate
148
, a middle plate
150
, and a bottom plate
152
. The three plates are of approximately equal outer dimension, said dimension being approximately equal to the outer dimension of the base curve lens mold carrier
18
. In a preferred embodiment, the plates are generally rectangular and of such a size to allow at least eight symmetrically arranged lens molds to fit within its dimensions. In another preferred-embodiment, the shape of the outer dimensions of the plates is square, and the size of plates allows at least sixteen symmetrically arranged lens molds to fit within its dimensions. In operation, the three plates are fixedly attached to each other, for example, by screws
159
that are placed at the circumferencial edge of the cleaning assembly.
Referring now to
FIG. 25
,
FIG. 26
, and
FIG. 27
, a top plate
148
has a top surface
154
, a bottom surface
156
, gas injection hole
158
, vacuum hole
160
, and receiving slots
162
. The top plate
148
is attached to a connector
84
. The bottom surface
156
contains a milled recess
164
, having an outer diameter generally smaller than and symmetrical with the outer perimeter of the top plate
148
, thereby creating a ridge
166
along the outer perimeter of the plate. Ridge
166
contains channel
168
which houses an o-ring or other appropriate sealing device. FIG.
24
. Again, the sealing device forms a pneumatic seal to allow the inflow and outflow of gas are routed through the intended channels when the plates are assembled. The recess also contains raised cylindrical portions
170
and
176
situated in the central portion of bottom surface
156
. Raised cylindrical portions
170
house receiving slots
162
thereby creating cylindrical ridges
172
which contain channels
174
. Channels
174
house O-rings or other appropriate sealing devices. FIG.
26
.
Raised cylindrical portion
176
houses vacuum hole
160
thereby creating cylindrical ridge
178
which contains channel
180
. Channel
180
houses an o-ring or other appropriate sealing device. FIG.
24
.
Referring now to FIG.
28
and
FIG. 29
, a base curve middle plate,
150
, having a top surface
182
and bottom surface
184
is attached to the base curve top plate
148
, thereby forming a cavity
186
defined by middle plate top surface
182
and top plate recess
164
. Base curve middle plate
150
contains a hole
188
in axial alignment with base curve vacuum hole
160
and of approximately the same diameter as vacuum hole
160
. Hole
188
and vacuum hole
160
establish fluid communication between the top surface of the base curve top plate
154
and the bottom surface of the base curve middle plate
184
. Base curve middle plate
150
also contains two holes or receiving slots
190
that are in axial alignment and of approximately the same diameter as top plate receiving slots
162
.
The base curve middle plate
150
also contains a plurality of orifices
192
providing fluid communication between cavity
186
and middle plate bottom surface
184
. In a preferred embodiment, there are eight orifices
192
which are arranged symmetrically. Orifices
192
preferably contain a nozzle
194
, or other means to direct the flow of gas through orifice
192
, which provides an inflow of compressed gas onto the lens mold that is to be cleaned. FIG.
33
. Annular extensions
196
which are in axial alignment with orifices
192
and which have an inner diameter approximately equal to the diameter of orifices
192
extend from the middle plate bottom surface
184
.
Referring now primarily to
FIG. 30
,
FIG. 31
, and
FIG. 32
, a base curve bottom plate
152
having a top surface
198
and a bottom surface
200
is attached to base curve middle plate
150
. FIG.
23
. The top surface
198
contains a recess
202
having an outer perimeter generally smaller than and symmetrical with the outer perimeter of the plate thereby creating an outer ridge
204
. Outer ridge
204
contains a channel
206
which houses an o-ring. FIG.
24
. Within recess
202
are two raised cylindrical portions
208
which house receiving slots
210
thereby creating cylindrical ridges
212
. Ridges
212
contain channels
214
, which house o-rings. FIG.
23
. When base curve bottom plate
152
is attached to base curve middle plate
150
, a cavity
216
, as shown in
FIG. 23
is created by recess
202
, and middle plate bottom surface
184
.
Base curve bottom plate bottom surface,
200
, contains a plurality of raised cylindrical portions
218
having an inner diameter and an outer diameter thereby defining a cylindrical ridge
220
and the cylindrical wall of a recess
222
having a definite depth situated within cylindrical portion
218
. Optionally, a sealing means, especially an elastomeric sealing means, e.g., O-ring, is attached to the cylindrical ridge
220
, especially at the bottom thereof. Cylindrical recess
222
extends upward into base curve bottom plate
152
to a point intermediate top surface
198
and bottom surface
200
. In a preferred embodiment shown in
FIG. 30
, there are eight cylindrical portions
218
symmetrically arranged and in axial alignment with base curve middle plate orifices
192
.
A second cylindrical recess
224
having a diameter smaller than the diameter of cylindrical recess
222
extends downward from the bottom of recess
202
and is axially aligned with cylindrical recess
222
and establishes fluid communication between recess
202
and cylindrical recess
222
. Second cylindrical recess
224
is of sufficient diameter to allow middle plate annular extensions
196
to substantially occupy recess
222
thereby defining an annular space
226
. Annular space
226
maintains fluid communication between cylindrical recess
222
and cavity
216
.
Operation of the Base Curve Cleaning Assembly
In operation, base curve mold cleaning assemblies
26
and base curve lens mold carriers
18
are arranged so that cylindrical recesses
222
are in substantially axial with base curve carrier holes
52
. The base curve cleaning assembly
26
is lowered by positioning means
82
to place ridge
218
close to the flange of the lens mold, e.g., approximately {fraction (15/1,000)} of an inch above the base of the lens mold, thereby forming a substantially enclosed area. FIG.
33
. Alternatively, especially. when the ridge
218
is equipped with sealing means, the base curve mold cleaning assembly
26
is lowered to place the sealing means-of the ridge
218
on the flange of the lens mold, thereby pneumatically sealing the lens mold and the cylindrical recess
222
. Two channels of fluid communication are created. The first channel consisting of hole
158
, cavity
186
, orifices
192
and annular extensions
196
allow compressed gas to flow at greater than atmospheric pressure from an outside source (not shown) into cylindrical recess
222
to dislodge any debris residing on the lens mold. Preferably, the gas is supplied to the cleaning assembly at a pressure of about 15 psi to about 25 psi, more preferably about 20 psi. Gases suitable for the invention include nitrogen, carbon dioxide and air, and desirably, the gas is deionized. This flow of gas is shown schematically in FIG.
23
and FIG.
33
.
The second channel of fluid communication is under the influence of a vacuum and provides an outflow of gas. Preferably, the outflow device applies between about 1.0 inch of Hg and about 2.0 inches of Hg, more preferably about 1.5 inches of Hg, of vacuum force at the vacuum hole
160
of the cleaning assembly. The channel is used to remove the gas and debris located around the lens mold. Beginning with recess
222
, the gas and any debris present leave cylindrical recess
222
via annular space
226
and proceed through cavity
216
through middle plate hole
188
and out top plate vacuum hole
160
into a vacuum line (not shown). Again, gas injection and application of the vacuum can occur independently, simultaneously or sequentially and can be of variable duration. For example, the vacuum is applied first and then quickly the pressurized gas is applied to ensure that all the debris located on the lens mold and in the recess
222
is removed through the annular space
226
.
After the lens molds are cleaned the lens molds proceed to subsequent stations in the lens manufacturing process.
The invention has been described in detail, with reference to certain preferred embodiments, in order to enable the reader to practice the invention without undue experimentation. However, a person having ordinary skill in the art will readily recognize that many of the components and parameters may be varied or modified to a certain extent without departing from the scope and spirit of the invention. Furthermore, titles, headings, or the like are provided to enhance the reader's comprehension of this document, and should not be read as limiting the scope of the present invention. Accordingly, the intellectual property rights to the invention are defined only by the following claims and reasonable extensions and equivalents thereof.
Claims
- 1. An apparatus for cleaning an ophthalmic device comprising at least one ophthalmic device carrier, a conveying device for conveying said ophthalmic device carrier, and a cleaning station to receive said ophthalmic device carrier, wherein said cleaning station comprises at least one movable cleaning assembly which forms an at least substantially enclosed area around the ophthalmic device to be cleaned and comprises an inlet for injecting compressed gas onto the ophthalmic device and an outlet for providing an outflow from said enclosed area to remove debris.
- 2. An apparatus according to claim 1 wherein said ophthalmic devices are contact lens molds.
- 3. An apparatus according to claim 1 wherein said gas is air.
- 4. An apparatus according to claim 3 wherein said air is deionized.
- 5. An apparatus according to claim 1 wherein said gas is nitrogen.
- 6. An apparatus according to claim 1 wherein the outflow is created by a vacuum source.
- 7. An apparatus according to claim 1 wherein said cleaning assembly forms a fully enclosed area around said ophthalmic device to be cleaned.
- 8. An apparatus for cleaning front curve contact lens molds comprising at least one front curve lens mold carrier, a conveying device for conveying said front curve lens mold carrier, and a cleaning station to receive said front curve lens mold carrier wherein said cleaning station comprises at least one movable cleaning assembly which forms an at least substantially enclosed area around the front curve lens mold to be cleaned and comprises an inlet for injecting compressed gas onto the front curve lens mold and an outlet for providing an outflow of gas from said enclosed area to remove any debris.
- 9. An apparatus according to claim 8 wherein said cleaning assembly is adapted to inject compressed gas onto the front curve lens molds to dislodge any debris located on the front curve lens molds and to provide a vacuum for removing any debris present, and wherein said cleaning station, which receives said front curve lens mold carrier, further comprises:a) four legs, spaced apart with each having an upper and lower portion; b) two parallel cross support members, each attached to the upper portion of two of said legs; c) a mounting plate having a top surface and a bottom surface movably engaging said cross support members; and d) at least one means for providing vertical movement of said cleaning assembly, wherein said means for providing vertical movement of said cleaning assembly is attached to the bottom surface of said mounting plates.
- 10. An apparatus according to claim 9 wherein said means for providing vertical movement of said cleaning assembly is a pneumatic cylinder.
- 11. An apparatus according to claim 9 wherein said cleaning assembly further comprises a proximity sensor.
- 12. An apparatus for cleaning base curve contact lens molds comprising at least one base curve lens mold carrier, a conveying device for conveying said base curve lens mold carrier, and a cleaning station to receive said base curve lens mold carrier, wherein said cleaning station comprises at least one movable cleaning assembly which forms an at least substantially enclosed area around the base curve lens mold to be cleaned and comprises an inlet for injecting compressed gas onto the base curve lens mold and an outlet for providing an outflow of gas from said enclosed area to remove any debris.
- 13. An apparatus according to claim 12 wherein said cleaning assembly is adapted to inject compressed gas onto the base curve lens molds to dislodge any debris located on the base curve lens maids and to provide a vacuum for removing any debris present, and wherein said cleaning station, which receives said base curve lens mold carrier, further comprises:a) four legs, spaced apart with each having an upper and lower portion; b) two parallel cross support members, each attached to the upper portion of two of said leg; c) a mounting plate having a top surface and a bottom surface movably engaging said cross support members; and d) at least one means for providing vertical movement of said cleaning assembly, wherein said means for providing vertical movement is attached to the bottom surface of said mounting plates.
- 14. An apparatus according to claim 13 wherein said means for providing vertical movement of said cleaning assembly is a pneumatic cylinder.
- 15. An apparatus according to claim 13 wherein said cleaning assembly further comprises a proximity sensor.
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Date |
Country |
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DE |
0 693 325 |
Jul 1995 |
EP |
2 353 468 |
Jun 1976 |
FR |
G 2 253 271 |
Sep 1992 |
GB |
55100112 |
Jul 1980 |
JP |
WO 9501229 |
Jan 1995 |
WO |