MXPA97002424A - Removal of lipo colado mold assemblies, through c - Google Patents

Abstract

The present invention relates to an apparatus for demolding a mold assembly comprising a front curve mold having a central section of lens mold with a surrounding flange, and a corresponding back curve mold having a central section of mold of lenses with a surrounding flange, and molded ophthalmic lenses that are formed between the back bend molds, and wherein the tabs of the front curve and back curve molds are separated from each other, which comprises: a) a pallet of support for supporting the mold assembly, b) a wedge separation accessory including at least one separation wedge positioned between the spaced tabs of the front curve molds and the back curve of the mold assembly, and c) means for causing movement relative translational between the wedge separation accessory and the support vane to progressively separate the front curve mold from the mold posteri curve

Description

DESMOLDEO DE ENSflHBL.ES OF MOLD OF LENTE COLRDQ BY WEDGE BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates generally to a wedge stripping apparatus and method for unmolding cast lens mold assemblies in which a molded assembly, consisting of a front curve, a spaced rear bend and a formed molded lens between them it is separated or demolded in a way that improves the simplicity and efficiency of the demoulding operation. More particularly, the present invention generally pertains to an apparatus and method for producing ophthalmic contact lenses in cast contact lens mold assemblies and, in particular, an apparatus and apparatus that provides improved removal of Ophthalmic contact lenses molded from the molds in which these are cast. The present invention is particularly suitable for molded ophthalmic lenses such as hydrogel contact lenses, although it also has applicability to other small high-precision ophthalmic lenses such as lens lenses. The present invention is related to the patent application Serial No. 08 / 257,801, filed on June 10, 1994, for Apparatus and method of demoulding, and is also related to the patent application No. of seri 08/258, 265, filed on July 10, 1994, for Method and separation equipment by the ser-.

DESCRIPTION OF THE PRIOR ART Since the ophthalmic lens industry has grown and in particular the industry related to the supply of contact lenses that are provided for periodic frequent replacement, the number of contact lenses that needs to be produced has increased dramatically . Fisto has led manufacturers to make possible automated methods and devices that are adaptable to automated practices and consistent work. It is generally known in the prior art to manufacture ophthalmic lenses, as well as soft hydrogel contact lenses, by molding a ring or a monomer mixture in a mole as one made of polystyrene or polypropylene. Examples of this prior art can be found in the patents of E.U.fl. Nos. 5,039,459, 4,889,664 and 4,565,348. These patents describe the requirement of a polystyrene mold in which the materials, chemicals and processes are controlled so that the mold portions do not require excessive force to be separated by contacting the lens or each other. In contrast to the above polystyrene molds, another example is the use of polypropylene or polyethylene molds as described in the US patent. No. 4,121,896.

The mold assembly for molding an ophthalmic contact lens typically includes a lower concave mold portion called the front curve and a top convex molding portion called the back curve. The concave surface of the lower frontal curve and the convex surface of the upper posterior curve define between them a mold cavity for a contact lens. A particular problem in the prior art is that the front curve and back curve molds are normally surrounded by a flange and the rnonomber or rormomer mixture is supplied in excess to the concave front curve mold prior to the assembly of the molds. Once the molds are placed together, defining the lens and forming an edge, the rnonornero or excess rnonornero mixture is expelled from the mold cavity and rests on or between the flange of one or both mold portions. . Under polymerization, this excess material forms an annular ring around the mold assembly, which resists the separation of the mold portions during a demolding operation. A prior art known method for separating the mold portions applies heat to the back bend mold through a stream of hot air. The hot air stream is directed against the exterior of the rear bend mold from which the heat is conducted towards the upper surface of the lens. The heat is transferred by thermal conduction through the posterior curve mold., the molded lens and the front curve mold. The heating of the back curve mold can be carried out in two sequential steps, a preheating step and a heating / separation step. In the heating / separation stage the mold is held in place and fingers of separation are inserted into the flange of the rear curing mold. Subsequently a force is applied to the back bend mold by means of the separation fingers during a heating cycle. When the temperature is required has been reached, the back bend mold is separated and one end thereof is lifted by the separation fingers. After the rear curve mold portion has been uncoupled from the front curve mold portion on at least one side, the mold exits the heater. The rear curve mold and the annular container are then completely removed. Although the aforementioned method has some efficacy in assisting in the removal of a lens from between opposing mold portions, the temperature gradient obtained from the rear curve mold heated to t from the lens to the front curve mold is relatively small. The method of the above technique has not been satisfactory since the induced thermal gradient is not sufficient to completely and repeatedly separate the mold portions. Accordingly, a second method of the prior art has also been developed in which the. The rear curve mold portion is radiated with electromagnetic radiation emanating from a being, which is absorbed therein to cause a substantial temperature gradient between the rear curve mold portion and the contact lens that It is being unfastened. The temperature gradient causes a differential expansion and a deepening of the surface of the heated rear curve mold portion relative to the lens surface to decrease the adhesion between the two and assist in the separation of the mold portions. , leaving at the same time the lens in the front cur-va mold portion. The posterior curve mold portion preferably irradiated by a laser that produces radiation with a wavelength between 1 μ and 20 jjrn. The separating fingers are joined together if to form a U-shaped separator and the laser beam is directed through the U-shaped opening in the U-shaped separator to irradiate the mold portion of the U-shape. back curve. Accordingly, much development has taken place in the prior art in heating methods of the posterior curved mold prior to the separation of the mold halves. However, the heating technique is only one aspect of the demolding process. The mechanical method for separating the mold halves is also a critical aspect of the demolding process. A one-sided separation technique has been used in a contact lens manufacturing line. This technique has been modified in several ways, all of which are based on discrete movement of double side or all sides. In all cases, the roll assembly has remained stationary while the mechanical separation or demoulding operation is carried out.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, it is a principal object of the present invention to provide a wedge stripping apparatus and method and method for cast lens mold assemblies, which can easily and repeatedly separate the lens mold portions without "tinting the lens". formed between them. A further object of the present invention is the provision of a method and apparatus for separating a back curve mold from a front curve mold of a contact lens mold assembly, which improves the simplicity and efficiency of the operation of demolding. In a preferred embodiment, a substantial temperature gradient is created by any known prior art heating technique between the back bend mold and the contact lens formed in the cavity of the contact lens mold assembly. Another object of the present invention is to provide an automated apparatus and method for mechanically separating the mold halves in a consistent and reliable manner to thereby improve the production of defect-free contact lenses and minimize lens tearing and rupture. of the lens mold parts. A further object of the present invention is to carry out such demolding or separation using a stationary or movable wedge to separate the mold halves of a cast contact lens mold assembly, which can use any suitable type of transfer of heat as one of the various embodiments described herein. The present invention relates to a mechanical technique that employs a wedge, either stationary or movable, which repeatedly separates a rear bend mold from a front curb mold in a programmed manner, and subsequently allows removal vacuum of the rear curve mold. This technique can be employed with a variety of heating modes and has a simple, easy-to-clean, low-cost, highly repeatable and unique mechanical scope for separating or unmolding cast contact lens mold assemblies. The present invention has at least the following four main and novel characteristics and advantages: Continuous processing The existing demold provisions and procedures are discrete operations with the product indicated in a stationary position. The mechanical de-molding operation occurs later as a discrete sequence of events. The wedge detolling range of the present invention when used with a discrete or semi-discrete heating process has the ability to be continuous, since the product never has to stop moving relative to the wedges. One advantage is that a very low wedge inclination or profile would allow a much higher capacity at relatively low cost compared to the existing discrete prior art processes.

Integrated Repeatability Using a well-machined wedge profile with an appropriate pallet driver or impeller, the mold separation procedure is extremely repeatable because the separation geometry is directly aligned to the same profile in each cycle. Different wedge profiles can be exchanged depending on which lens or lens design is being used.

Low cost Once a wedge profile and a heating procedure is optimized for a certain lens / lens mold design, multiple units of this design can be reproduced at low cost relative to the existing discrete demolding operations of the prior art. Simplicity fl erence of a heating process that is also required by the existing prior art operations, the only movable part needed is the indicator or driver of the product. All of the other components can remain stationary, which makes troubleshooting and maintenance easier. In accordance with the teachings of this, the present invention provides an arrangement for unmolding a mold assembly, which includes a front curve mold having a central mold section with a surrounding flange and a corresponding rear bend pattern also having a central rnolder section with a surrounding flange being molded a contact lens between these. The tabs of the front curve and rear curve molds are spaced apart and parallel to one another. A support pallet is provided to support the mold assembly. A wedge spacer facility provides at least one spacer wedge positioned between the spaced tabs of the mold assembly, and the wedge spacer assembly and support paddle are translated relative to one another to progressively separate the front curve mold from the mold. posterior cur-va mold. In more detail, the wedge separator installation is stationary mounted and suspended on the support vane, and an impeller or indicator conveys to the supporting pallet relative to the stationary wedge separator installation mounted to a position in which the separating wedge is positioned between the spaced tabs of the mold assembly and separates or unmolds the front curve and rear curve molds. An upper vacuum duct is provided, positioned on the support vane downstream of the wedge spacer installation in the transport direction of the support vane, to vacuum separate rear bend molds. Guide rails are also provided for mounting the support pallet for its translational movement relative to the fixed wedge separator installation. The wedge separator installation may include a wedge positioned on one side of the mold assembly, or two wedges positioned on opposite sides of the mold assembly. In several preferred embodiments, the support pallet supports an arrangement of n x m of rnolde assemblies. In alternative embodiments, the wedge spacer installation may include a spacer wedge for each row of the n x arrangement, or two spacer wedges for each row, one positioned on each side of the row. In alternative embodiments, the nx arrangement of the mold assemblies may include a mold structure that interconnects a front bend bend nxm arrangement, with a single rear bend mold placed on each interconnected front bend mold, or may include - an arrangement of nxm of individual non-connected front curve molds, with an individual rear curve row placed on each individual front curve mold. An oppressive stabilizer bar can be placed on top of the mold assemblies during the removal operation to maintain the mold assemblies properly placed on the support blade during the demolding operation. In several described embodiments, the back bend mold is heated so that the heat is conducted by the back bend roller to cause a temperature gradient between the back bend mold and the lens being demolded, with the temperature gradient causing a differential expansion and change of the surface of the posterior curve mold relative to the surface of the lens to decrease the adhesion in the same to ensure in the separation of the molds, while the lens is in the front curve mold . The heating can be provided by any suitable arrangement, such as by a full hot air chamber and nozzle to direct hot air into the back bend mold of the mold assembly, or by a radiant infrared heater and a reflector to direct the infrared radiation on the back bend mold of the mold assembly. In those modalities where the support palette supports a n x m arrangement of the rnolde assemblies, a heat module can be placed on the support vane having n x m openings, each one having a substantial diameter equal to the diameter of a lens. Alternatively, a heat conducting probe assembly can be used, which has a nx rn arrangement of heat conducting probes that make contact with the rear curing mold of the nxm arrangement of the mold assemblies, to conductively heat the mold assembly. disposition of the assemblies of rnolde. A lifting cylinder goes up and down on heat conducting probe assemblies relative to the support paddle. During the operation, the weights of the individual heat conductor probes are maintained in the arrangement of the mold assemblies during the demoulding to maintain the arrangement of the mold assemblies properly placed on the support blade during the removal . A lifter cam is provided to lift the driver probe assembly from the pallet following the desmoid as an indicator transports the pallet past the assembly lift cam.

BRIEF DESCRIPTION OF THE DRAWINGS The above objects and advantages of the present invention for a wedge release and molding method can be better understood by one skilled in the art with reference to the following detailed description of several preferred embodiments thereof, all together with the accompanying drawings in which similar elements are designated by the identical reference numbers through the different views, and where. Fig. 1 illustrates a front elevation view of a support pallet holding a 2 x 4 array of contact lens assemblies therein, each consisting of a lower front curve mold and an upper rear curve mold, which define between them a recess of rnolde for a contact lens; Figure 2 is an elongated and sectional side elevational view of a contact lens assembly, which illustrates detail of the construction of the lower front curve mold and the upper rear curve; Figure 3 is a diagrammatic representation of a first embodiment of a demolding arrangement of the wedge type according to the teachings of the present invention which utilizes a two-sided removal of a rear bend pattern; Figure 4 illustrates an arrangement similar to Figure 3, but where the back curve is removed by a wedge applied on only one side, so that the significant cam or wedge found in the profile exists mainly only in one wedge. side; Figures 5 and 6 respectively illustrate front elevational and flat top views of a wedge arrangement disposition of a side, heated with air, according to the present invention; Figure 7 illustrates an infrared heated mode of a wedge type demolding apparatus on one side; Figure 8 illustrates a front elevational view of a conductively heated embodiment of a wedge demolding apparatus on one side; Figures 9 and 10 are respectively front elevational and flat top views of the same embodiment of Figure 8 presented in a full assembly view of the parato; Figures 11 and 12 are respectively top elevation and flat top views of a wedge-type demoulding mode which uses single lens rnolde assemblies in a free pallet., DETAILED DESCRIPTION OF THE DRAWINGS By making the drawings in detail, and particularly in FIGS. 1 and 2, FIG. 1 illustrates a front elevational view of a supporting pallet 10 supporting therein an arrangement, typically an arrangement of 2 x 4, of contact lens mold assemblies 12, one of which is illustrated in more detail in FIG. 2. FIG. 2 is a side elevational and sectional elevation view of a contact lens mold assemblies 12, which consists of a lower front curve mold 14 and an upper rear curve mold 16, which defines between them an olde cavity for contact lenses 18. The front curve and rear curve mold halves 14 and 16 are preferably formed of polystyrene but can be any suitable thermoplastic polymer that is sufficiently transparent for ultraviolet light to allow irradiation through them with light to promote polymerization. bsequent of soft contact lenses. A suitable thermoplastic such as polystyrene also has other desirable qualities such as being moldable for optical quality surfaces at relatively low temperatures, which have excellent flow characteristics and which remain amorphous during molding, if crystallized, and which have the lowest reduction during the cooling The front curve mold half 14, defines a central curve section with an optical quality concave surface 20, having a circumferential circular knife edge 22 extending around it. The knife edge 22 is desirable to form a sharp plastic radius starting line and join (edge) to subsequently mold the soft contact lenses 18. A generally parallel convex surface 24 is separated from the concave surface 20., and an essentially annular flange 26 is formed which extends radially outwardly from the surfaces 20 and 24. The concave surface 20 has the dimensions of the front curve (energy curve) of contact lenses that are going away. to be produced by the roller assemblies, and is sufficiently smooth so that the surface of the contact lenses formed by the polymerization of a polymerizable composition in contact with the surface is of optically acceptable quality. The front curving mold half is designed with a thickness typically 0.B rnrn, and an effective rigidity to transmit heat through it and to support the excessive forces applied to separate the mold half from the assemblies of rnolde during a de-molding operation. The front curve mold half 14 also defines a generally triangular tongue 28, FIGS. 2 and 9, integral with the flange 26 which is projected on either side of the flange. The tongue 28 is essentially uniplane and extends towards a hot injection tip which provides molten plastic to form the front curve half of the l. The rear curve mold half 16 defines a central curve section with an optical quality convex surface 32, a generally parallel concave surface 34 spaced apart from the convex surface 32, and an essentially annular umplana flange 36 formed extending radially toward outside the surfaces 32 and 34. The convex surface 32 has the dimensions of the posterior curve (which rests on the cornea of the oo) of a contact lens to be produced by the rear curve mold half, and is sufficiently smooth « Thus, the surface of a contact lens formed by the polymerization of a polimerizable composition in contact with the surface is of optically acceptable quality. The rear curve mold half is designed with a thickness, typically 0.6 mrn, and effective rigidity to transmit heat through them quickly and to withstand the forces applied to separate the half "Je rnolde of the roller assembly" Je during the demolding. The rear curve mold half 16 also defines a generally triangular tongue 38, similar to the triangular tongue 28, integrates (.the flange <.;? it is projected from one side of the tab. The tongue 38 extends toward a hot injection tip that provides molten thermoplastic to form the rear curve backing half. During the molding process of the contact lenses, an excess amount of polymer or polymer mixture is initially deposited in a front curve pattern, and then a rear curve pattern is placed over the front curve and pressed down. against it.

This results in an excessive polymer in the mold cavity being displaced and discharged therefrom and "forms an excess polymer ring 42 out of the knife edge 22. The flanges 26 and 36 are designed to secure the Desinoid and partly handle, and also protect the optical surfaces and the knife bople. The geometry of the triangular tabs 28 and 38 serves an additional function upon straightening - and orienting the assembled rear diagonal curve curved assemblies 12 prior to removal. When a front bend mold half or curve 14 is assembled with a back bend mold half or curve 16, a recess 14 is formed between the two separate flanges and projecting tabs that is important for the removal. The gap between the tabs is preferably in the range of 1.0 rn-3.0 rn, and is required to assist in the de-molding operation, as will be explained in more detail below. Referring to FIGS. 1 and 2, the contact lens mold assemblies 12 are supported on the vane 10 with the annular flanges 26 and the tabs 28 of the front bend pattern 14 which is located 1 below the surface. upper of the pallet 10. The annular flanges 36 and the tabs 38 of the rear curve olde 16 are lifted above the upper surface of the pallet, to allow a mechanical separation member to be inserted between the separated flanges 26, 36 of the frontal curve and posterior curve. Figure 3 is a diagrammatic representation of a first embodiment of a wedge-type demoulding apparatus and method according to the present invention that utilizes a two-sided removal of the back bend mold. The stripping apparatus illustrated in FIG. 3 includes a schematically illustrated blade vane 10, a front bend mold 14, a rear bend mold 16, and a mold release wedge 44. The apparatus and method of removing the figure 3 operate as follows. STEP 1: The mold assembly 12, which includes the rear curved edge 16, the front curve mold 14, the lens 18 and the excess polymer ring 42, is heated (preferably from the top) during or immediately before step 1. The heating procedure may occur exclusively from step 1, or may continue through the complete demoulding operation. At the point illustrated in step 1, the wedge 44 does not stretch the rear curve 16 and the front curve mold. 14, but it is completely coupled between the flanges 26 and 36 of the molds «back curve and front curve. Note that the wedge 44 does not interfere with the excess polymer ring 42 since such interference would cause a failure condition that would render the procedure ineffective. STEP 2: As shown in the top view, the pallet 10 and the assembly "1e mold 12 are moved by a product or driver indicator" 46 to proceed along the wedges 44. The angle of inclination or cam Wedge and / or feed rate determine the speed of the posterior curve removal. An inclination angle or non-linear wedge cam and / or feed speed < 1an result in a removal rate «ie non-linear posterior curve. The heating procedure also affects the acceptable removal rate. The amount of the excess polymer 42 also influences the process conditions. STEP 3: At this point, the roll assembly has been moved by the product indicator 46 to point in the wedges 44 so that the back bend mold 16 with the excess polymer ring 42 is completely separated from the front curve mold 14 and lenses 18. The required amount of separation or wedge height for effective disinfecting depends primarily on the size of the excess polymer ring and the efficiency of the heating operation. A typical embodiment of the present invention would allow more wedge height than is theoretically needed to ensure complete mold removal. At this point or directly thereafter, the back bend mold 16 now separated and the polymer ring 42 are removed by an upper vacuum stripping system 47 which deposits the rear curves in a waste container for recirculation.

Figure 4 illustrates an arrangement similar to Figure 3, where the rear curve is removed by means of a wedge applied from the side only. This one-sided removal configuration is modeled from the one-sided separation procedure previously used and currently used in a contact lens manufacturing process. Figure 4 illustrates a one-side wedge demolding mode in which there is a significant wedge or wedge profiled mainly only in a wedge 44. Step 3 can also be modified to use wedge profiling in the wedge not profiled above. This would allow the back bend mold to be removed effectively once the one-sided separation is complete.

Wedge heated with a hot re The mode of figures 5 and 6 is slightly different from the modes previously explained in the foregoing because in this mode a mold assembly arrangement of 2 x 4 is formed by a mold structure 64 interconnected which physically interconnects each of the front curve molds 14. Each back curve mold 16 is a single component that is individually fabricated in each front curve mold 14. Figures 5 and 6 respectively illustrate plan views upper and front elevation of a disposition modality < The one-sided wedge heated with air that was experimentally tested successfully in "reduced ring" polymer. The apparatus and method of removal illustrated in Figures 5 and 6 include a wedge accessory or assembly 48 which has a cam or wedge profile 50, a supporting support blade 52 defining a mold structure cavity for an assembly. of frame structure 64, precision guide rails 54, an upper wedge assembly 56, hot air nozzles 58, and a hot air plenum 60. FIG. 6 illustrates a top plan view of a roller frame 64. which defines a mold assembly arrangement of 2 x 4, poe? cion «1o in a support pallet 52. The structure of rnolde 64 and the pallet 52 are arranged to present a row of 4 mold assemblies towards the separation fitting of wedge 48. Therefore, the wedge separation fitting 48 provides 2 separation wedges 44 for each of the 4 roller assemblies for a total of 5 separating wedges. The three middle separation wedges are positioned between two adjacent mold assemblies, and provide a wedge or cam per-row on both sides thereof to serve the two adjacent mold assemblies. The wedge separation accessory 48 is positioned in a suspended manner by the support vane in the upper assembly 56, which is supported by 2 lateral vertical supports 57 interconnected by the top assembly disposed on-line hop 56 in which the wedge separation accessory 48 is mounted.

Dur- before the operation, the structure of rnolde 64 is placed on the pallet 52 in the position marked co or 62. A heating process occurs during which hot air emanates from the hot air plenum 60 through the air nozzles hot 58 and directed over each roll cavity of roll structure 64. After a given heating period, paddle 52 and roll structure 64 are spaced or moved from right to left at a specified speed, such as by A hydraulic cylinder 66. Precision guide rails 54 guide this movement below the wedge portion of the wedge assembly 48. After that the profile of the wedge or cam 50 has caused the rear curve 16 to be Separate completely from the front curve mold 14, the rear curve mold 16 with excess polymer ring 42 remains stationary in the wedge assembly 48 while the blade 52 and the mold structure 64 continue moving completely to the left. At this point, the front curve mold structure 14 with the lenses 18 is removed from the vane 52. The unit is then repositioned again for a new cycle.

Wedge heated with infrared. Figure 7 illustrates an infra-red heating mode of a single-sided wedge device and release apparatus that has been proven experimentally. It < oloca a mold structure 64 in a moved pallet 1 52. Heat is applied to the lens portions of the structure of olde by means of an infrared emitter 70 < * which is activated and controlled by a solid state relay 72. A heat shield and reflector * concentrates the infrared heat to the heating pad 76. The heating pad 76 is a "thin metal plate with 8 holes". n diameter equal to the lenses and with cent -al lines are common with the olde cavities on the mold structure 64. The heat dial 76 concentrates the heat on the lens portion 18 in the rear curve mold 16 and not in the flange or frame structure. After a specified temperature and exposure time, the paddle 52 moves at a specified speed < 1e right to left. After a given amount of travel, the cam or wedge profiling 78 associated with the wedge or assembly accessory 48 causes the rear curing mold 16 to be completely separated from the front curve mold structure 64. The pallet 52 Continues to its leftmost position, where the mold structure 64 is removed with the lenses 18. The vane 52 is then posi cloned again, and the unit is ready for the next operation cycle.

Wedge heated with conductive probe. Figure 8 illustrates a front elevation view of a heated mode by conduction of an apparatus of «Single-sided single-sided moldings designed to use molds with reduced excess polymer rings 42. Figures 9 and 10 are respectively top plan and front elevation views of the same embodiment of Figure 8 presented in a full assembly view of the apparatus. The mold release arrangement illustrated in the figures 0, 9 and 10 includes a wedge assembly 80, comprised of a plurality of spacer wedges 81, a mobile support paddle 82, a vacuum drive bell 84, a heat conducting probe assembly 86 that It has a 2 x 4 arrangement of heat conducting probes 88, a lifting cam of the heat conducting probe 90, a conductive probe assembly lifting cylinder 92, a hydraulic paddle drive cylinder 94, a controller / process timer 96, and hydraulic fluid containers 98. During operation, the heat conducting probe assembly 86 is lifted vertically by the lift cylinder 92 by the lift cam 90 so that the mold assembly 64 can be placed on the support pallet 82 without interfering with the conductive probes 88. The assembly of conductive probes 86 is then lowered by means of the lifting cylinder 92 by means of the lifting cam 90 so as to The conductive probes 88 rest under their own head on the portions of the lenses on the non-critical side of the back bend molds 16. At this point, the heat is conducted through the conductive probes 88 to the mold assemblies of the mold. glasses. During the operation, the conductive probes 88 have heater cartridges * is < That are kept at a specific temperature. After a programmed period has elapsed in the W (* controller / cont.). Time of the process 96, the paddle 82 moves in a direction «Je« Jerecha left by the hydraulic cylinder 94 advancing des « The reservoirs 98. The conductive probe assembly 86 moves simultaneously with the pallet 82 so that the weight of the conductive probe assembly 86 0 remains completely on the rear curve molds 16. After a given distance of travel, the excess curve curves of back curve mold begin to separate by the cam or wedge profiling associated with the wedge assembly 80. At a point before the complete 5 separation of the rear curve mold, the cam profile on the lifting cam of the conductive probe assembly 90, lifts the conductive probe assembly 86 and cleans the conductor probes 88 of the roller assemblies. As the pallet 82 continues to the left, the rear curves Ib are completely separated from the structure of anterior curves 64 and are emptied by withdrawing by means of the vacuum hopper bell 84. Then the pallet 82 reaches its extreme point. left and the movable structure of frontal curve 64 with the lenses 18 is removed. The unit is then established again and is ready for the next operation cycle. One purpose of keeping the conductive probes 88 in contact with the back bend molds 16 while the molds 16 are engaging the wedge assembly 80 is to provide and maintain a normal force in each mold. counteract a cutting force generated by the per-row angle in the wedge and acting on the partially released lenses. The "hydraulic transmission 94" cylinder operates and is used to maintain * a constant maximum force in the vane in the direction of travel thereof. This constant maximum force allows the paddle 82 to decrease or increase * the speed depending on how much resistance is encountered during the separation of the posterior curve. This feature helps compensate for process variations due to temperature variations, excess polymer ring sizes, etc.

Assemblies of a single mold in a pallet Figures 11 and 12 are respectively front views in elevation and in the upper floor «Je a generic modality« Wed casting demoulding that uses assemblies of singular lens rnolde 12 in a free pallet 10 , as illustrated in FIG. 1, as opposed to the use of a mold structure 64 as illustrated in FIG. 6. The apparatus illustrated in FIGS. 11 and 12 includes a pallet 100, pallet guides. 102, wedges 104, a vacuum trawl hood 106, an oppressor / stabilizer bar 108, and single mold assemblies 12.

Function During operation, single-lumen assemblies 12 are heated either discretely or continuously by any known effective technique such as those described above. The paddle 100 moves from right to left by suitable spacing mechanisms. As the assembly of a single rnolder 12 passes under the oppressor / stabilizer bar 108, they are retained and captured in their individual nests in the pallet 100. This results in an accurate reference localization of the flanges «Je bend posterior and frontal curve. Before the single-ended assemblies 12 exit under the pressure / stabilizer bar 108, the wedges 104 have begun to engage, but without applying tension to the rear curve molds. The squeezing bar 108 prevents "single-sided assemblies" from being moved out of their nests or lifted by the wedges 104. At some point in the path, the rear curve mold 16 and the ring Excess polymer 42 are completely separated from the front curve pattern 14 and the lenses 18. The vacuum drive bell 106 then removes the back curve molds. The paddle 100 continues its course from right to left until "all the assemblies of a single mold 12 are separated, and then moves to the next station" Je operation. Although various embodiments and variations of the present invention have been described in detail herein for a wedge mold separation and molding method, it should be apparent that the description and teachings of the present invention suggest Many alternative designs for experts in the field.

Claims (36)

NOVELTY OF THE INVENTION CLAIMS

1. - An apparatus for demolding a mold assembly comprising a front curve mold having a center section of lens rnolde with a surrounding flange, and a corresponding back bend mold having a central section of lens mold with a surrounding flange, and molded ophthalmic lenses that are formed between the front curve and rear curve molds, and wherein the flanges of the front curve and rear curve molds are separated from each other, which comprises " : a) a support pallet to support the assembly of rnolde; b) a wedge spacing fitting including at least one wedge of post-cloned spacing between the spaced tabs of the front curve molds and the rear curve of the mold assembly; and c) means for causing relative translational movement between the wedge separation accessor-LO and the support vane to progressively separate the front curve mold from the rear curve mold.

2. A unit for demolding a mold assembly according to claim 1, further characterized in that it includes means for stationary mounting the wedge separation accessory suspended above the support blade, and a means of spacing for transporting the pallet "Je support in relation to the accessory" he wedge separation mounted stationary and in a position where the separation wedge is positioned between the spaced tabs of the mold assembly.

3. An apparatus for releasing a mold assembly as claimed in claim 2, which includes an upper vacuum conduit, placed on the support blade and in a downward direction, ie the wedge separating the device in the driving direction of the support pallet, to raise the separated rear bend molds by vacuum.

4. An apparatus for the removal of a mold assembly as claimed in claim 2, further characterized in that guide rails mount the support vane for its translational movement with respect to the fixed wedge separator device.

5. An apparatus for removing molds from a mold assembly as claimed in claim 1, including a vacuum lifter for removing the separate bend molds during the "Je" operation.

6. An apparatus for demolding a roller assembly as claimed in claim 1, further characterized in that the wedge-separating device includes wedges placed on opposite sides and between the separate flanges of the mold assembly.

An apparatus for demolding a roller assembly as claimed in claim 1, further characterized in that the support pallet supports a nx rn arrangement of rim assemblies

8. An apparatus for unrolling a mold assembly as claimed. claim 7, further characterized in that the wedge spacer device includes at least one spacer wedge n, one for each row of the nx rn arrangement

9. An apparatus for unmolding a mold assembly as claimed in claim 7, further characterized in that the wedge-separating device includes two spacer wedges for the row of the nxm arrangement, placed one on each side of each row.

10. A unit for removing a roller assembly as claimed in claim 7, further characterized in that the arrangement of the mold assemblies includes a mold structure that interconnects a nx in arrangement of molds. Frontal curve and a single curve rear row is placed on each front-connected curve rnolde l.

11. An apparatus for demolding a mold assembly as claimed in claim 7, further characterized by the fact that the nx arrangement of the mold assemblies includes a nxm "Je mole" individual mandrel not connected to the front curve, and an individual mold of rear curve is placed on each individual mold of frontal curve.

12 .-- An apparatus for de-casting - a mold assembly as it is? <Figure l in claim 11, further characterized in that a lower stop stabilizer bar is placed over the mold assemblies during the removal operation to maintain the mold assemblies properly placed on the support blade during the desmoid operation .

13. An apparatus for shaping a mold assembly as claimed in claim 1, which includes means to heat the rear curve mold, which heat is conducted by the back bend mold to cause a gradient. temperature between the rear curve mold and the lens being unrolled, the temperature gradient causing an expansion and a differential displacement of the surface of the posterior curve mold relative to the surface of the lens to decrease the adhesion between the same and help the separation of the molds, while leaving the lens in the front curve mold.

14. An apparatus for demolding a mold assembly as claimed in claim 13, characterized by the fact that the means for heating include a plenum of hot air and a nozzle to direct the hot air over the curve mold. back * of the mold assembly.

15. An apparatus for demolding a roller assembly as claimed in claim 13, further characterized in that the means for heating includes a radiant infrared heater and a reflector for directing the infrared radiation on the rear curve rear wheel < j the assembly of rnolde.

16. An apparatus for demolding a mold assembly as claimed in claim 13, further characterized in that the support blade supports an arrangement n x rn of the mold assemblies.

17. An apparatus for demolding a mold assembly as claimed in claim 16, further characterized in that a heat cartridge having nx in openings is placed, each having a substantial diameter equal to that of the lamellae. lens, on the support pallet.

18. An apparatus for demolding a roller assembly as claimed in claim 16, further characterized in that the means for heating include a conductive probe assembly, which has a disposition of conductive heating probes. therein, which makes contact with each rear curve-of-the-mold arrangement of the mold assemblies, to conductively heat the arrangement of mold assemblies.

19. An apparatus for de-molding a mold assembly as claimed in FIG. Revetment 18, which includes a lifting cylinder for raising and lowering the heating conductor conductive probe to the support vane, and in which the weights of the conductive electric heating waves are dual. they remain on the arrangement of the mold assemblies during the demoulding to maintain the arrangement of the mold assemblies properly placed on the pallet «Je support uran I demold you.

20. An apparatus for demolding a roller assembly as claimed in claim 19, which includes a lifting cam "Jel conductive probe assembly" which lifts the conductive probe assembly from the blade after removing it while it is being removed. the means for setting the index drives a palette beyond the lifting read of the conductive probe assembly.

21.- A method to unmold a mold assembly, It consists of a mold for frontal curves having a central section of the lens mold with a surrounding flange, and a corresponding mold of rear curve which has a central section of the lens mold with a surrounding flange, and a Ophthalmic lens that is molded between the molds of the frontal curve and the posterior curve, and in which the tabs of the front curve and rear curve molds are separated one from the other, consisting of: a) drowsiness - attach the mold assembly on a support paddle; b) placing a wedge-separating device that includes at least one spacer wedge between the spaced-apart flanges of the front curve and rear curve molds of the mold assembly; and c) moving the wedge separating device and the support vane laterally in translation to progressively separate the front curve mold from the forward bend mold.

22. - A method for demolding - a mold assembly as claimed in claim 21, which further includes stationary mounting of the device separates "wedge of wedges suspended on the pallet" support, and drive the support pallet with respect to the separating device wedges mounted stationary and at a position in which the spacer wedge is placed between the flanges separated from the mold assembly.

23. A method for "molding a mold assembly" as claimed in claim 21, which includes separating the separate bend molds during the operation of "milling with a vacuum.

24. A method for "molding a mold assembly as claimed in claim 21, which includes placing wedges on opposite sides and between the flanges separated from the mold.

25. A method for removing a mold assembly as claimed in claim 21, including supporting an n x rn arrangement of the mold assemblies in the support pallet.

26.- A method of unmolding a mold assembly as claimed in claim 25, which also includes using separating wedges n, one for each row of the n x m arrangement.

27.- A method for demolding a standard form as claimed in claim 25, which includes using spacer wedges for each row of the n x rn arrangement, placed one on each side of each row.

28.- A method for shaping a roller assembly as claimed in claim 25, which includes interconnecting the nx rn arrangement of the mold assemblies with mold structure, and placing an individual mold of the rear bend on the ja inter-connected front curve.

29.- A "Jo" for "mold" a mold assembly as claimed in claim 25, which includes using a nx rn arrangement of individual unconnected front-curve molds, and placing an individual back-curved mold on each individual mold of frontal curve.

30. A method for demolding a roller assembly as claimed in claim 25, further characterized by applying a vertical releasing force to each of the mold assemblies during the stripping operation to maintain the mold assemblies properly positioned. in the support palette «During the drain operation.

31. A method for demolding a mold assembly as claimed in claim 21, which includes heating the rear curve mold, which heat is conducted by the back bend mold to cause a temperature gradient between the mold "Je The posterior curve and the lenses that are being demolished, cause the temperature gradient to expand and shift differentially from the surface of the posterior curve to the surface of the lens. The same and help the separation of the molds, while leaving the lens in the front curve.

32. An apparatus for demolding a roller assembly as claimed in claim 31 which includes directing hot air through a plenum of hot air and a nozzle onto the rear bend mold of the roller assembly.

33.- A method for de-molding mold assembly as claimed in claim 31, which includes directing infrared radiation over the rear bend pattern "Jel mold assembly to the Jor heat and radiant infrared reflector.

34.- A method for unmolding a mold assembly as claimed in claim 33, which includes supporting a mold assembly arrangement n x rn on the support blade.

35.- A method for designing a mold assembly as claimed in claim 34, which includes colocal-a heat cell having nx openings, each having a substi- tially equal diameter to the lens diameter. , on the support palette.

36. A method for unmolding a mold assembly as recited in claim 36, which includes contact with each subsequent bend mold in the nx rn arrangement of the mold assemblies, the means To calibrate include a heat conductive probe assembly, which has a nxm arrangement of conductive heating probes thereon to heat * conductively in the arrangement of mold assemblies. 37.- A method for removing a roller assembly as claimed in claim 36, which includes raising * and lowering the conductive probe assembly "Heating with respect to the blade" with a lifting cylinder. 38.- A method for demolding a mold assembly as claimed in claim 37, which includes maintaining the weights of the individual conductive heating probes on the arrangement of the mold assemblies during the de-molding operation to maintain the arrangement of the mold assemblies. the mold assemblies properly placed in the support vane during the demolding operation. SUMMARY OF THE INVENTION A demolding device for reliably and repeatedly mechanically separating contact assemblies from contact lenses without damaging the contact lens formed between them. The roller assembly includes a front curve pattern having a central mold section with a surrounding flange, and the mold corresponding to a rear curve that also has a central mold section with a surrounding flange, with a contact lens that is molded between them. A support pallet is provided to support the "Je molde" assembly. A wedge spacer device provides at least one spacer wedge placed between the flanges spaced apart from the mold assembly, and motion is imparted to the wedge spacer device and the support paddle relative to each other to progressively separate the mold. of front curve and the rear bend mold. In one embodiment, the wedge spacer device suspended above the support vane is mounted stationary, and a mechanism drives the support vane relative to the wedge spacer device * stationary mounted to a position in which the spacer wedge is placed between the spacer wedges. tabs separated from the «Je rnol« assembly and separating or unmolding the front curve and rear curve molds. In several preferred embodiments, the support pallet supports the spinner assemblies in the n x m arrangement. In alternate embodiments, the wedge spacer device may include a spacer wedge pair for each row for the n x arrangement, or two spacer wedges for each row, placed one on each side of the row. In alternative embodiments, the nx rn arrangement in the wheel assemblies may include an olde structure interconnecting a nxm arrangement of front curve molds, an nxm arrangement of individual, unconnected front curve molds with a single curl shape. - Rear row placed on each mold of front curve. EA / 3N / BS / GC / ycl / avrn / l ss / l pm P97 -309