MXPA97005227A - Apparatus and method of investing conta lenses - Google Patents

Abstract

The present invention relates to apparatus for inverting a plurality of contact lenses from a convex position toward an upwardly concave position, comprising: a) a tray having opposite, upper and lower surfaces, having a common thickness w2 and includes a plurality of perforations formed tatally through said band from said upper surface toward said lower surface, said plurality of contact lenses being placed on said upper surface wherein each of said lenses is placed on at least one of said perforations; a source for directing an air jet of predetermined velocity against said lower surface of said tray, said jet of air passes through said perforations colliding against and injecting said lenses, which are in said convex position above, into said concave upward position and a substantially flat surface to hold said tray, said surface The flat surface includes a recessed groove having a length L1 that is at least as long as said w2 of said tray, said source being located within said groove wherein said air jet is directed out of said groove towards a flat surface, which said tray can move through said flat surface on said slot wherein said jet of air passes through and hits said lower surface of the tray, passing through said perforations and ivirtiendo said lenses to the passers on said slot.

Description

APPARATUS AND METHOD OF INVESTING CONTACT LENSES.

BACKGROUND OF THE INVENTION The present invention relates to a material handling apparatus for altering the orientation of an article between different stages of a manufacturing process. More specifically, it relates to an apparatus and method for reversing a plurality of non-planar, delicate workpieces (e.g., contact lenses) between separate phases of the manufacturing process that require, for example, sequential processing treatments on the surfaces opposite concave-convex lenses. Delicate small workpieces, such as contact lenses, pose a considerable management problem in terms of the method or methods with which they pass through the multiple stages of a manufacturing process. Since scratched, cracked or broken lenses should be rejected and discarded, it is highly desirable to develop material handling methods that make minimal direct contact with the lenses in a manner that reduces the possibility of them experiencing destructive deterioration. The need to fully invest a lens from one stage of the manufacturing process to another may indeed present the greatest material handling challenge for this type of workpiece. The total inversion of a contact lens is necessary, for example, when performing plasma treatments on the opposite convex and concave surfaces of silicone hydrogel lenses. Until now, the inversion of contact lenses between plasma treatments of the opposite surfaces of a lens has been carried out manually with a pair of tweezers, laborious process that is expensive, slow and can contribute to operator injuries due to repetitive movement. A known material handling apparatus for inverting an ophthalmic lens between phases of the manufacturing process is shown in U.S. Patent No. 4,006,563 issued to Essilor International on February 8, 1977. In the '563 machine, ophthalmic castings not flat are inverted, one by one, when they are released from a suction mechanism 75 together with a tilting rod 83 that extends transversely above a moving conveyor belt. When the molded piece is released, its leading edge hits the swinging rod, while the trailing edge falls on the conveyor belt, the pivoting rod and the mobile conveyor cooperating to pivot the molded part on the conveyor belt (ending with the convex side). upwards) . The lens reaches the opposite end of the conveyor belt, where it is picked up by a second suction cup mechanism and deposited in a second battery of work stations. Although the '563 machine seems effective when inverting an ophthalmic lens between two batteries of work stations, it would not be an acceptable means to invert a finished contact lens, because the impact of the edge of the lens against a tilting rod would probably cause deterioration destructive to the lens, resulting in the rejection of an unacceptably high amount of lenses. In addition, it is evident that the '563 mechanism can only invert one molded part each time, which makes it inefficient to be used in high volume production environments, such as the contact lens manufacturing business. It is also known to use a controlled stream of compressed air in an article orienting apparatus. For example, as seen in U.S. Patent No. 3,734,268, issued to Burger et al. On May 22, 1973, an air current is used to pivot covers, located in the "upside down" position, advancing to along a conveyor belt 18, to a "face up" position. (The term "upside down" means that the concavity of the lid formed by the flat circular portion and the surrounding vertical wall ("skirt") faces downwards to the conveyor belt. "Face up" means that the concavity faces upwardly. the conveyor belt). The air stream 48 is directed upwards through an opening 38 formed in a horizontal shelf 36 on which the conveyor belt 18 extends. Curved walls 34 and 52 spaced laterally and longitudinally, located on opposite sides of the tape 18, direct the covers, one at a time, to a position where a side edge of each through cover (front wall 52) hangs slightly from the corresponding side edge of the tape. With the opening 38 of the underlying shelf 36 outwardly adjacent to said edge of the belt, the air stream is directed so as to strike against the downward facing surface of the hanging portion of the cap. Thus, the covers in the "upside down" position will be tilted in a lateral direction to an "up" position by the air flow due to the forces acting against the concavity of the lid. Apparently, covers that are already in the "up" position are not affected by the air current. Although the device of '268 seems suitable for investing durable plastic caps when they go down a conveyor belt, it would not be an acceptable method to invest very delicate items, such as contact lenses, because the edge of the lens will probably be damaged when pushed to the correct position for the wall elements 34 and 52. In addition, the '268 mechanism does not provide for the orientation of more than one item at a time, a desirable feature in high volume production environments, such as the lens manufacturing business contact. A reliable and safe apparatus and method is therefore needed to invert a plurality of contact lenses when they are transferred from one stage of the manufacturing process to another, while also maintaining an acceptable waste ratio produced by the handling method. of material . SUMMARY OF THE INVENTION The present invention satisfies the above needs and issues by providing a new and unique apparatus and method for reversing a plurality of contact lenses between separate processing steps, which are extremely simple to implement and operate. More specifically, a plurality of lenses are first placed, with the convex side facing up, on a flat supporting surface, such as a tray. The tray includes a plurality of small spaced holes with diameters substantially smaller than any of the lenses. The convex, facing-up surfaces of the lenses are then treated as necessary. For example, the tray can be placed in a plasma chamber where the convex surfaces of the lens are treated in known manner to increase their hydrophilic properties. The tray, with treated lenses still placed on top of it, is then taken out of the chamber and passed over an elongated stream of air that flows through and is directed so that it hits the lower surface of the tray. By arranging the lenses in parallel rows spaced in the tray, a plurality of lenses can be inverted simultaneously in each row by moving the tray above the air stream in a direction generally perpendicular thereto. When each row passes over the air stream, all the lenses in the row are inverted simultaneously. More particularly, a quantity of the air stream, at a predetermined speed, distance and angulation with respect to the tray, passes through the perforations of the tray to hit the concave surfaces, facing downwards, of the lenses . The force of the movable air stream striking said surface of the lens serves to lift and invert the lens in the tray, now looking at its convex side up the tray. In addition, each lens comes to rest substantially in the same position as it was before the inversion, which provides a desirable method of handling material to invest contact lenses, because: 1) the lenses, including their peripheral edges, are not touched by any type of mechanical instrument other than the tray that supports them, thus considerably reducing the possibility of deterioration of the lens and minimizing waste relationships; 2) a plurality of lenses can be inverted simultaneously in the same tray; 3) the lenses are inverted in their original positions in the tray, facilitating the following handling phases; and 4) the investment method is automated, thus substantially reducing the risk of operator injury. The tray with the inverted lenses now facing the concave side upwards can be reinserted into the plasma chamber for the final treatment of said lens surface. It will be appreciated that the apparatus and method of the present invention can be used in conjunction with processing steps other than plasma treatments which likewise require sequential treatments of the opposite convex and concave surfaces of the lenses. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a preferred embodiment of the invention, where spaced rows of contact lenses are supported on a perforated tray, with the convex side facing upwards, after having been subjected to a first stage of elaboration, where said surface of the lenses has been treated, but immediately before passing them over the elongated stream of air coming out of a slot located in a platform. Figure 2 is the view of Figure 1, depicting the tray while passing over the air stream (in the direction of the arrow), having already passed the first five rows of lenses (counting from the right) and having been inverted by the air stream, the sixth row being passed and being inverted by the air stream, and the last six rows being in the initial position with the convex side upwards. Figure 3 is a cross-sectional view, cut away, taken along line 3-3 of Figure 2, showing the source of the air stream placed in the recessed groove of the platform with a sixth lens. row in the process of being inverted by it. And Figure 4 is an enlarged view of the source of air stream of Figure 3, representing in transparency lines the reversal path of the lenses by the air stream.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, in the various figures there is shown an article orientation apparatus generally designated by the reference numeral 10, which is used to rapidly reverse a plurality of contact lenses 11 from a position with the convex side upwards to a position with the convex side downwards. As shown in Figure 1, the lenses 11 are initially placed with the convex side facing up on the upwardly facing horizontal surface 12 of a tray 14 in twelve parallel rows spaced R1-R12, with eight lenses in each row. Although it is preferred to arrange the lenses 11 in parallel rows spaced in the tray 14, as shown, for the reasons explained below, the number of rows and the number of lenses in each row can, of course, be varied as desired . It is appreciated that the surface 12 includes a plurality of perforations 16 formed entirely therethrough, which have a diameter substantially smaller than that of the lenses 11, so as to provide an air flow through the surface 12, also avoiding at the same time the accidental accommodation of a lens in a hole. Furthermore, it is preferred that there are perforations 16 in sufficient number and spacing on the surface 12 so as to ensure that any lens 11 placed on the surface 12 is placed on top of at least one, but preferably more than one, perforation 16. It is made Note that it is known to use a perforated tray, such as tray 14, to support lenses during a processing of the manufacturing process, such as treatment in a plasma chamber, for example. In this known process, the lenses are usually inverted manually in the tray between the sequential plasma treatments of the convex and concave surfaces of the lenses. In this case, the perforations of the tray are merely provided to provide adequate ventilation to the surface of the lenses facing down during the treatment and, as far as they reach the Applicant's knowledge, they have not been used in any type of material handling as in the present invention described and claimed herein. In Figure 1, it is understood that the lenses 11 have undergone the first stage of a two-stage processing treatment of the convex surfaces (top side) of the lenses 11, for example, a plasma treatment, where the tray 14 and the lenses 11 are placed in a conventional plasma chamber (not shown) for a predetermined period of time. After removal of the tray 12 and the lenses 11 from the plasma chamber, the tray 14 is placed on a substantially horizontal surface 18 having a width Wx that is preferably at least as large as the width W2 of the tray 14 for provide a suitable support surface for it. As can be seen very clearly in FIGS. 1, 3 and 4, an elongated recess slot 20 is formed in the surface 18 and traverses it, and has a length Li that is substantially equal to or greater than the width W2 of the tray 14. As described in detail below, an air source located below the surface 18 directs a controlled stream of air 22 upwardly through the slot 20 so as to reverse the lenses 11 from a position with the convex side upwards to a position with the convex side downwards when the tray 14 passes over the slot 20 in the surface 18 from left to right, according to the arrow in figure 1. Considering FIGS. 2-4, the tray 14 is approximately half of the process of passing over the slot 20, where an air current source 22 'is located. In the figures, the lenses of the first five rows R? ~ R5 have already passed and been inverted to a position with the concave side upwards, the lenses of row R6 are passing and being inverted by the air current 22, and the lenses of rows R7-R12 located to the left of the air stream are still in the initial positioning position with the convex side facing up. The inversion path taken by a lens when it passes over the air stream 22, is illustrated with lines of transparency in Figure 4. As seen, the lens 11 'of the sixth row R6, which at this point is placed directly on the air stream 22, it is being inverted in a counterclockwise direction, which is the direction opposite to the direction of advance of the tray. This is so because the leading edge 11 'of the lens is in the first part of the lens with which the air stream 22 will collide. As seen in Figure 1, the air stream 22 comes out of substantially the entire length Lx of the slot 20, such that all the lenses of a row are inverted simultaneously when the row passes over the slot 20. Thus, the source 22 'is elongated, so as to extend substantially over the entire length of the slot 20 to provide an air stream 22 that traverses the entire width W2 of the surface 12 of the tray. Furthermore, by controlling parameters such as the speed and angulation of the air stream with respect to the surface 12 of the tray, the lenses can be made to rest substantially in the same position as they were before the inversion, as shown, facilitating So to a large extent the following phases of material handling.

Once the tray 14 has passed completely above the air stream 22, all the lenses 11 are in an inverted position with the concave side upwards (as seen in the rows R1-R5), after which said The surface can be drawn as required in the second stage of the selected processing treatment. Thus, it can be appreciated that the present invention provides a fast, easy and reliable apparatus and methods for reversing a plurality of contact lenses between sequential processing steps that require treatments of the opposite convex and concave surfaces of the lenses. Although the invention has been described with respect to its preferred embodiment, those skilled in the art will note that various modifications can be made without departing from the full spirit and scope of the invention defined by the following claims. For example, the method can be more fully automated using a perforated conveyor belt instead of a tray, so the lenses, which are initially placed on the conveyor belt in a position with the convex side up, can enter a first processing station for treating said surface of the lenses, exit the first processing station and pass over a stream of air that traverses the conveyor belt so that they are inverted to a position with the concave side upwards in the conveyor belt, and then enter a second processing station to perform the treatment of said lens surface.

Claims (7)

1. CLAIMS 1. Apparatus for inverting a plurality of contact lenses from one position with the convex side upwards to a position with the concave side upwards, including: a) contact lens holder means having opposite upper and lower surfaces and which include a plurality of perforations formed therethrough, said plurality of contact lenses being placed on said upper surface, each of said lenses being placed on at least one of said perforations; and b) a source for directing an air stream of predetermined velocity against said lower surface of said contact lens support means, said air stream passing through said perforations and striking and inverting the lenses that are in said position with the convex side upwards to said position with the concave side upwards. The apparatus of claim 1, wherein said contact lens holder means includes a perforated tray having a width W2. The apparatus of claim 2 and further comprising a substantially planar surface for supporting said tray, said planar surface including a recessed slot having a length A that is at least as long as said width 2 of said tray, said source being placed within said groove, said air stream being directed out of said groove towards said flat surface, whereby said tray can be displaced through said flat surface above said groove, crossing said air stream and hitting said lower surface of the tray, passing through said perforations and inverting said lenses when they pass over said slot. The apparatus of claim 1, wherein said contact lens support means have a width W2 and said air stream is elongated and traverses substantially the entire width 2 of said contact lens support means. 5. A method of inverting a plurality of contact lenses from a position with the convex side upward to a position with the concave side up, said method including the steps of: a) providing a perforated contact lens support surface for said plurality of lenses, said supporting surface having opposite upper and lower surfaces; b) placing said plurality of lenses in said position with the convex side upwards on said upper surface of said support surface; and c) directing an air stream so as to collide against said lower surface of said support surface, whereby said air current passes through said perforations and inverts said lenses from said position with the convex side upwards to said position with the concave side up. The method of claim 5, wherein said air stream is an elongated air stream that completely traverses said bottom surface of said support surface, and said support surface is passed above said air stream in a substantially perpendicular direction. to the direction of said air stream. The method of claim 5, wherein said lenses are arranged in parallel rows spaced over said support surface, said air stream serving to simultaneously invert all the lenses of a row when said support surface passes over it.