Plastic and nonmetallic article shaping or treating: processes – Optical article shaping or treating
Reexamination Certificate
1999-01-12
2001-03-06
Vargot, Mathieu D. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Optical article shaping or treating
C264S002500, C264S040500, C425S150000, C425S449000, C425S452000, C425S808000
Reexamination Certificate
active
06197227
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to contact lens manufacturing. More particularly, the invention relates to a machine and method for manufacturing molded toric contact lenses.
A method of cast molding toric contact lenses is described in U.S. Pat. No. 5,611,970 issued Mar. 18, 1997 to Bausch & Lomb Incorporated, assignee herein, the entire disclosure of which is incorporated herein by reference. The method of the '970 patent involves providing anterior and posterior mold sections having concave and convex molding surfaces, respectively, which are placed together to form a lens-shaped mold cavity into which a monomer is deposited and cured to form a lens. The invention of the '970 patent places a ballast-forming feature on the anterior mold section and a toric-forming feature on the posterior mold section, with the anterior and posterior mold sections being alignable at multiple rotational positions. The mold sections themselves are injection molded using special optical tools which replicate the anterior and posterior mold surfaces on the respective mold sections which, in turn, form the optical anterior and posterior surfaces of the resultant lens. Although each mold section is used only once to make a single lens, by placing the ballast and toric features on the opposite mold sections, which may be aligned at any selected one of multiple rotational positions, a plurality of toric contact lenses may be formed, each having different rotational offsets between the ballast and toric features of the lens, by mold sections which are formed from the same optical mold tools. Although the '970 patent at Col. 5, lns. 6-16 suggests ensuring the selected rotational alignment between the mold sections by engaging a notch of the anterior mold section and rotating it on a support relative to indicia on the posterior mold section, there is no discussion of automated manufacturing or handling processes by which this may be carried out.
SUMMARY OF THE INVENTION
The present invention compliments the method of the '970 patent by providing a machine and method by which the rotational offset between the ballast and toric features of anterior and posterior mold sections may be automatically selected and passed through a full production cycle to form toric lenses of any desired rotational offset. Other than the inputting of the desired rotational offsets, the inventive machine and method requires very little operator intervention.
More particularly, the automated machinery of the invention is connected to and operated by a computer which is programmed to control the operation of the machine. The operator simply chooses and inputs the desired rotational offset between the anterior and posterior mold sections which is then transmitted to the appropriate machine parts which control the rotational alignment of the mold sections. The anterior and posterior mold sections are delivered to the machine via a pair of tubes in which the anterior and posterior mold sections are placed in stacked relation, respectively. The tubes are vertically oriented with respect to the machine with the mold sections being delivered through an opening in the bottom of the tube, one at a time. A glider plate is positioned directly beneath the vertically oriented tubes and is configured to receive a posterior and anterior mold section thereon. In the preferred embodiment of the invention, three pairs of mold sets are passed through a production cycle at a time.
The glider plate transports and deposits the posterior mold section at a predetermined position within the machine. A posterior mold handling rod is lowered over the posterior mold section and lifts the posterior mold section vertically upward. The glider plate then transports and deposits the anterior mold section onto the top end surface of the anterior mold handling rod, with the anterior and posterior rods being in axial alignment. An axis alignment tool is then moved to a location between the posterior and anterior mold sections, with the posterior mold-handling rod then lowered and engaging the posterior mold section with the upper-most portion of the axis alignment tool, and the anterior mold-handling rod rising vertically until the anterior mold section is engaged with the lower-most portion of the axis alignment tool.
The upper and lower halves of the axis alignment tool are each provided with an element which cooperatively engages with an element provided on each of the posterior and anterior mold sections, respectively. With the posterior and anterior mold sections engaged in the upper and lower halves of the axis alignment tool, the posterior and anterior rods are rotated about their common vertical axis until the cooperative elements on the mold sections engage with the elements on the stationary axis locator tool. The elements on the mold sections are formed thereon at the time the molds are injection molded, with the positions of the elements on the mold sections being predetermined and selected relative to the toric and ballast features on the optical surfaces of the mold sections. Thus, with these relative positions between the toric and ballast features and their respective mold aligning elements being known, the posterior and anterior rods may be rotated with respect to the stationary axis alignment tool until the toric and ballast features of the posterior and anterior mold sections are set to a 0°, or other known angular “home” position, respectively.
With the posterior and anterior mold sections at their “home” positions, the posterior and anterior rods, together with the posterior and anterior mold sections, are lifted and lowered, respectively, thereby disengaging the mold sections from the axis alignment tool which is then retracted to a position which is laterally spaced from the posterior and anterior mold handling rods. The anterior mold handling rod and anterior mold section are rotated according to the desired axial offset which was programmed into the computer, relative to the stationary posterior mold handling rod and mold section. This establishes the desired axial offset between the toric and ballast features of the yet unfinished lens. A measured quantity of liquid monomer is then injected into the anterior mold section, and the posterior mold rod with posterior mold section is moved toward the anterior mold section until the posterior mold section engages the anterior mold section with a predetermined clamping pressure. The posterior mold handling rod is then retracted, leaving the posterior mold section capped to the anterior mold section. The mold sections can then be moved to a location for curing of the monomer into a lens.
REFERENCES:
patent: 3632696 (1972-01-01), Jones
patent: 3946982 (1976-03-01), Calkins
patent: 4208364 (1980-06-01), Shepherd
patent: 4208365 (1980-06-01), LeFevre
patent: 4307046 (1981-12-01), Neefe
patent: 4383672 (1983-05-01), Kreuttner
patent: 4407766 (1983-10-01), Haardt
patent: 4422984 (1983-12-01), Neefe
patent: 4469646 (1984-09-01), Rawlings
patent: 4522768 (1985-06-01), Roscrow
patent: 4555372 (1985-11-01), Kunzler
patent: 4636338 (1987-01-01), Neefe
patent: 4680998 (1987-07-01), Council
patent: 4693446 (1987-09-01), Orlosky
patent: 4749530 (1988-06-01), Kunzler
patent: 4781452 (1988-11-01), Ace
patent: 4786444 (1988-11-01), Hwang
patent: 4980993 (1991-01-01), Umezaki
patent: 5066431 (1991-11-01), Briggs
patent: 5076683 (1991-12-01), Glick
patent: 5110278 (1992-05-01), Tait
patent: 5147585 (1992-09-01), Blum
patent: 5200121 (1993-04-01), Hagmann
patent: 5244377 (1993-09-01), Danker
patent: 5252056 (1993-10-01), Horner
patent: 5269105 (1993-12-01), Fleenor
patent: 5271875 (1993-12-01), Appleton
patent: 5288221 (1994-02-01), Stoerr et al.
patent: 5300262 (1994-04-01), Glick
patent: 5330203 (1994-07-01), Fleenor
patent: 5456864 (1995-10-01), Wickes
patent: 5517259 (1996-05-01), Blum
patent: 5528321 (1996-06-01), Blum
patent: 5598234 (1997-01-01), Blum
patent: 5611970 (1997-03-01), Apollonio
patent: 5620717 (1997-04-01), Wickes
patent: 5916494 (1999-
Appleton William John
DeRyke Kevin Jacob
Dobner Michael Henry
Ormiston Allen Lee
Powell Ian Andrew
Bausch & Lomb Incorporated
McGuire Katherine
Vargot Mathieu D.
LandOfFree
Toric axis alignment machine and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Toric axis alignment machine and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Toric axis alignment machine and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2454518