Abstract:
A method and apparatus for practicing the method of making toric contact lenses having a toric axis and ballast axis located on the anterior and posterior surfaces of a lens. Detectable features are formed on the anterior and posterior mold sections corresponding to the location of the toric axis and ballast axis, respectively. An axis alignment tool having detecting means thereon is used to set the mold sections to a known angular position. The desired axial offset is input into a computer which establishes the axial offset between the mold sections.

Description:
This application claims benefit of Provisional Application Ser. No. 60/071,617 filed Jan. 16, 1998. 
    
    
     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 &amp; Lomb Incorporated, assignee herein, the entire disclosure of which is incorporated herein by reference. The method of the &#39;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 &#39;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 &#39;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 &#39;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. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a front elevational view of the inventive machine shown in a first “home” position, with some portions thereof broken-away for the sake of clarity; 
     FIG. 2A is a top plan view of FIG. 1; 
     FIG. 2B is an enlarged, fragmented, perspective view of a first glider plate; 
     FIG. 3 is a front, elevational view of FIG. 1 showing the machine in a second stage of movement; 
     FIG. 4 is a front, elevational view of FIG. 1 showing the machine in a third stage of movement; 
     FIG. 5 is a front, elevational view of FIG. 1 showing the machine in a fourth stage of movement; 
     FIG. 6 is a front, elevational view of FIG. 1 showing the machine in a fifth stage of movement; 
     FIG. 7 is a front, elevational view of FIG. 1 showing the machine in a sixth stage of movement; 
     FIG. 8 is a front, elevational view of FIG. 1 showing the machine in a seventh stage of movement; 
     FIGS. 9-11 illustrate a flow chart describing the various stages of movement of the machine through a single production cycle; 
     FIG. 12 is a perspective view of an anterior mold section; 
     FIG. 13 is a top plan view of FIG. 12; 
     FIG. 14 is a cross-sectional view taken generally along line  14 — 14  in FIG. 13; 
     FIG. 15 is a perspective view of a posterior mold section; 
     FIG. 16 is a top plan view of FIG. 15; 
     FIG. 17 is a cross-section view as taken generally along line  17 — 17  in FIG. 16; 
     FIG. 18 is a cross-sectional view as taken generally along line  18 — 18  in FIG. 16; 
     FIG. 19 is a cross-sectional view of a toric contact lens; 
     FIG. 20 is a schematic cross-sectional view of an assembled mold; 
     FIG. 21 is a perspective view of the axis alignment tool of the machine; 
     FIG. 22 is a bottom plan view of FIG. 21; 
     FIG. 23 is a top plan view of FIG. 21; 
     FIG. 24 is a cross-sectional view as taken generally along the line  24 — 24  in FIG. 23; and 
     FIG. 25 is a top plan view of three axis alignment tools positioned in a second glider plate. 
    
    
     DETAILED DESCRIPTION 
     The inventive machine  10  and individual components thereof are seen in FIGS. 1-8 and  20 - 24 . An anterior and posterior mold section pair  12 , 14 , respectively, is shown in FIGS. 12-18 which is used for making a toric contact lens  16  as seen in FIG. 19 using machine  10 . A flow diagram describing the various stages of a production cycle of machine  10  is shown in FIGS. 9-11. 
     Machine  10  is operable to manufacture toric contact lenses having any desired axial offset between the toric and ballast features formed on the opposite optical surfaces of a toric contact lens. Referring to FIG. 19, toric lens  16  illustrates a representative toric contact lens which may be made in accordance with the machine and method of the present invention. Central zone  18  of posterior surface  20  is toric, i.e., this zone has a toric surface that provides the desired cylindrical correction for an astigmatic cornea Posterior surface  20  may optionally include at least one peripheral curve  22  surrounding the toric central zone  18 . For the described embodiment, central zone  24  of anterior surface  26  is spherical, and the spherical curve is matched with central zone  18  to provide the desired spherical correction to the lens. Anterior surface  26  may optionally include at least one peripheral curve  28  surrounding central zone  24 . 
     Lens  16  is provided with ballast so that the lens maintains a desired rotational orientation on the eye. For example, as schematically shown in FIG. 19, peripheral section  30  may have a different thickness than opposed peripheral section  32  of the lens periphery. As is known in the art, the ballast is oriented about an axis, and toric contact lens prescriptions define the offset of this ballast axis from the cylindrical axis by a selected rotational angle (usually expressed as number of degrees). As used herein, the term “offset” is inclusive of angles of 0 degrees through 180 degrees, wherein the cylindrical axis is coincident with the ballast axis. 
     Anterior and posterior mold sections  12 , 14  are each formed by a known injection molding process using a respective pair of optical tools (not shown) which form the mold optical surfaces  12 ′, 14 ′ into the mold sections  12 , 14 , respectively, with the anterior mold concave surface  12 ′ ultimately forming the anterior (outer-away from the eye) surface  26  of the toric lens  16 , and the posterior mold convex surface  14 ′ ultimately forming the posterior (inner-against the eye) surface  20  of the toric lens  16 . When the anterior and posterior mold sections  12 , 14  are brought together as seen in FIG. 20, a mold cavity  38  is formed between facing mold surfaces  12 ′, 14 ′ which corresponds to the shape of the contact lens molded therein. Accordingly, in accordance with the present invention, posterior mold convex surface  14 ′ has a toric central curve zone having a cylindrical axis (for forming the toric posterior surface  20  of lens  16 ), and anterior mold concave surface  12 ′ has a configuration that will provide ballast to a lens molded in molding cavity  38 . Of course, surfaces  12 ′, 14 ′ may also include curves for forming desired peripheral curves on the lens, and the central zones of surfaces  12 ′, 14 ′ may be designed to provide a desired spherical correction to the molded toric contact lens. 
     As discussed above, a toric lens prescription defines the axial offset between the toric axis and ballast axis of the posterior and anterior surfaces  20 , 26  of the lens, respectively. Different toric prescriptions thus have different axial offsets between these parameters. Machine  10  is operable for selecting and manufacturing toric lenses having the desired axial offset using mold sections  12 , 14 . Furthermore, the axial offset is easily changed between production cycles whereby the same machine  10  is capable of making toric lenses of many different axial offsets/prescriptions. Such a machine has not heretofore existed. 
     Referring to FIGS. 1-8, machine  10  includes a main housing  40  supported on multiple legs  42 . Housing  40  is a generally rectangular structure including bottom and top walls  44 , 46  and opposite side wall pairs  48 , 50  and  52 , 54 , respectively, all defining an internal space  56 . Housing configurations other than rectangular are of course possible. Housing  40  is preferably fully enclosed to maintain an oxygen-free atmosphere of nitrogen, and to protect and reduce accumulation of dust on the various components held within the housing, although selected portions of housing  40  are preferably easily removable to provide access to space  56  and the components held therein, as needed. 
     A pair of anterior and posterior mold supply tubes  58 , 60 , respectively, are positioned vertically through openings formed in top wall  46  of housing  40 . The top ends  58 ′, 60 ′ of the supply tubes  58 , 60  are open and wherein the anterior and posterior mold sections  12 , 14  are individually deposited and stacked, respectively. During operation of machine  10 , it is intended that the anterior and posterior supply tubes  58 , 60  be continuously stocked with anterior and posterior mold sections  12 , 14 , respectively. 
     A first movable glider plate  62  is positioned within housing  40  over a support plate  64 . A first ram  66  attaches to the back edge  62 ′ of plate  62 , whereby ram  66  and plate  62  are movable between a “home” position S 1  seen in FIGS. 1,  2  and  6 - 8 , an intermediate position S 2  seen in FIG. 3, and a fully extended position S 3  seen in FIGS. 4 and 5. As seen best in FIGS. 2A and 2B, plate  62  includes three notched areas which are each configured with a pair of rounded openings  62   a,b;    62   c,d;  and  62   e , 62   f,  the openings of each pair adapted to removably receive an anterior and posterior mold section  12 , 14  therein, respectively. When plate  62  is in the “home” position of FIGS.  1 , 2  and  6 - 8 , an anterior and a posterior mold section  12 , 14  drop freely from tubes  58 , 60  into the rounded openings  62   a,b;    62   c,d;  and  62   e,f  of plate  62 , respectively. In this regard, it is noted that machine  10  is adapted to manufacture three toric lenses simultaneously; hence, a total of three pair of supply tubes  58 , 60  are provided for depositing three pair of anterior and posterior mold sections  12 , 14  into the three pair of rounded openings of plate  62  at a time. Although the invention is described herein in an embodiment which manufactures three toric contact lenses at a time, it will be understood that machine  10  may be modified to manufacture anywhere from one toric lens to a potentially infinite number of toric lenses at a time, as desired. This first step in the production cycle is labeled FC 1  in FIG.  9 . 
     With an anterior and posterior mold section pair  12 , 14  having been deposited into opening pairs  62   a,b;    62   c,d;  and  62   e,   62   f,  respectively, an anterior mold section  12  is located in each of the rear openings  62   a,    62   c,  and  62   e,  while a posterior mold section  14  is located in each of the forward openings  62   b,    62   d  and  62   f  located adjacent forward edge  62 ″ of plate  62 . Once the mold sections  12 , 14  are nested inside a respective plate opening, ram  66  is activated to extend itself and plate  62  to the left until plate  62  reaches a second stop position S 2  seen in FIG.  3 . In second stop position S 2 , each forward opening  62   b,    62   d,  and  62   f  of plate  62  is located directly between a pair of anterior and posterior handling rods  68 , 70 , respectively, which are aligned along a common axis x—x (only one pair of anterior and posterior rods are shown in the drawing for the sake of clarity). The anterior handling rod  68  has a top surface  68 ′ which extends through an opening in housing bottom wall  44 , and upon which a respective posterior mold section  14  freely rests in stop position S 2  of plate  62 . (See also FC 2  in FIG.  9 ). 
     At this time, posterior handling rod  70  is lowered onto a respective posterior mold section  14  located in openings  62   b,    62   d,  and  62   f.  A vacuum line V provided axially through posterior rod  70  is activated at this time to secure by suction posterior mold section  14  to the end  70 ′ of each posterior handling rod  70 . Once the vacuum is applied, posterior handling rod  70  is raised with the posterior mold section  14  attached thereto by vacuum pressure (FIG. 4) (See also FC 3  in FIG.  9 ). 
     With posterior mold sections  14  having been removed from forward openings  62   b,    62   d  and  62   f,  piston rod  66  extends further to the left until it reaches a third stop position S 3  seen in FIG.  4 . At third stop position S 3 , rear openings  62   a,    62   c  and  62   e  are now located directly between anterior and posterior handling rods  68 , 70 , with forward openings  62   b,    62   d  and  62   f  being now located to the left thereof. In this position, each anterior mold section  12  rests atop the top surface  68 ′ of a respective anterior handling rod  68 . (See also FC 4  in FIG.  9 ). 
     With posterior handling rods  70  raised and each holding a respective posterior mold section  14 , and an anterior mold section  12  resting on surface  68 ′ of each anterior handling rod  68 , a second glider plate  72  is moved by an arm  74  to the right to a location between posterior and anterior handling rods  68 , 70  as seen in FIG.  5 . (See FC 5  in FIG.  9 ). As seen best in FIG. 25, glider plate  72  includes three circular openings  72   a,    72   b  and  72   c  wherein three axis alignment tools  76  are removably positioned, respectively. One such alignment tool  76  is seen in more detail in FIGS. 21-24. The axis alignment tool is used to establish the desired axial offset between the toric and ballast axes of the lens to be molded as described more fully below. 
     More particularly, alignment tool  76  is formed of three cylindrical segments including a top segment  78 , bottom segment  80  and middle segment  82 , each of increasing diameter, respectively. A small lever  84 , whose function is explained below, projects radially from bottom section  80 . Referring to FIG. 25, the openings  72   a-c  of plate  72  are each of a diameter only slightly larger than the diameter of the bottom section  80  of each tool  76 . Each opening  72   a-c  further includes a radial section  72   a′ ,  72   b′  and  72   c′  such that a tool  72  may be fit into each opening with the bottom sections  80  thereof sliding into the circular sections of the openings  72   a-c,  and the levers  84  of the tools being passed through radial sections  72   a′ ,  72   b′ , and  72   c′  of the openings  72   a,    72   b  and  72   c,  respectively. Since the diameters of openings  72   a-c  are only slightly larger than the diameter of bottom sections  80  of tools  76 , the middle segments  82  thereof come to rest on the top surface  73  of plate  72  about the perimeters of the openings  72   a-c  in the fully inserted position of the tools  76  in openings  72   a-c.  Also, to ensure that each tool  76  is rotationally fixed to plate  72  (for purposes to be explained), the lever hinge pin  84 ′ is keyed into a slot (not shown) in plate  72 . 
     When glider plate  72  is moved to the right to the location seen in FIG. 5 as described above, the openings  72   a-c,  with tools  76  located therein, are positioned along the axis x—x of a respective pair of anterior and posterior handling rods  68 , 70 . At this time, each pair of anterior and posterior handling rods  68 , 70  are moved along their common axis x—x toward one another until the anterior mold section  12  carried by anterior handling rod  68  engages the bottom segment  80  of tool  76 , and the posterior mold section  14  carried by posterior handling rod  70  engages the top segment  78  of tool  76  (FIG.  5 ). (See also FC 6  in FIG.  10 ). At this time, anterior and posterior handling rods  68 , 70  are rotated about their axis x—x to establish each of the toric and ballast axes of mold sections  12 , 14  at their “home” positions. (See also FC 7  in FIG.  10 ). 
     More particularly, as seen in FIG. 5, the anterior mold section  12  is inserted into the open bottom section  80  of tool  76 . As seen in FIGS. 14 and 24, anterior mold section  12  has an outer diameter d 1  at the upper segment  13  thereof, which diameter d 1  is slightly smaller than the inner diameter d 2  of bottom segment  80  of tool  76 . As such, as the anterior handling rod  68  is raised, the upper segment  13  of anterior mold segment  12  slides into the open bottom section  80  of tool  76 . Anterior mold section  12  includes a top surface  15  encircling concave mold surface  12 ′. As anterior mold section  12  is inserted into tool bottom section  80 , anterior mold top surface  15  strikes lever  84  which is biased downwardly by a ball and spring assembly  85 . Referring again to FIG. 5, as anterior handling rod  68  continues to rise, top surface  15  pushes lever  84  upwardly (toward upper segment  78  of tool  76 ) until lever  84  activates a proximity sensor (not shown) positioned adjacent thereto. Activation of the proximity sensor sends a signal informing computer  11  (FIGS. 1 and 2) that anterior and posterior mold sections  12 , 14  are engaged with axis alignment tool  76 . 
     Referring to FIGS. 18 and 24, posterior mold section  14  has a minimum inner diameter d 3  located adjacent convex mold surface  14 ′ which is slightly larger than tool upper segment  78  outer diameter d 4 . As such, as posterior handling rod  70  is lowered, the wall  17  of posterior mold section  14  slides over tool upper segment  78 . 
     As stated above, when anterior mold top surface  15  strikes and depresses lever  84 , the proximity sensor informs computer  11  that anterior and posterior mold segments  12 , 14  are filly engaged with tool  76  as described above. In response, computer  11  sends a signal back to machine  10  which causes anterior and posterior handling rods  68 , 70  to rotate about common axis x—x via drive belts  68 ″, 70 ″, respectively (FIG.  1 ). 
     As seen in FIGS. 14 and 24, a notch  15 ′ is formed in mold top surface  15  and a pin  83  is fixed to and extends downwardly from lever  84 , respectively. Notch  15 ′ is formed in top surface  15  directly opposite the ballast axis of mold surface  12 ′. Rotation of anterior handling rod  68  together with anterior mold section  12  ultimately causes pin  83  to engage notch  15 ′, at which point anterior mold section  12  is at its “home” position. Pin  83  drops into notch  15 ′ together with lever  84 , thereby deactivating the proximity sensor which informs computer  11  the anterior mold sections  12  are at their “home” positions. 
     As seen in FIGS.  16 , 18 , a flange  19 ′ is formed on wall  19  of posterior mold section  14  directly opposite the toric axis of mold surface  14 ′ thereof. As seen in FIGS. 21,  23  and  24 , a tab  79  is formed on the upper edge  78 ′ of tool upper segment  78 . With posterior mold section  14  engaged with tool upper segment  78 , rotation of posterior handling rod  70  together with posterior mold section  14  causes flange  19 ′ on mold section  14  to strike and abut tab  79  on tool upper segment  78 . This establishes posterior mold segment  14  at its “home” position. 
     Anterior handling rod  68  is rotated a distance sufficient to ensure pin  83  will drop into notch  15 ′, preferably, this is a distance greater than 360 degrees. Both the anterior and posterior handling rods  68 , 70  stop rotating at about the same time. Since the stopping of the rotational movement of the handling rods is not instantaneous and may go beyond the engagement positions of the mold sections with the tool  76 , the degree of frictional force between the mold sections and their respective handling rods is made such that any continued rotation of the handling rods will be independent of the mold sections which are now rotationally stationary due to their respective engagement with the axis alignment tool  76 . In other words, the static frictional force between the mold sections  12 , 14  and their respective handling rods  68 , 70  is strong enough to cause the mold sections  12 , 14  to rotate with the respective handling rod  68 , 70  until the mold sections  12 , 14  engage with the alignment tool  76 , at which time this static friction is converted to dynamic friction. 
     Other frictional interfaces of concern are between the mold sections  12 , 14  and the alignment tool  76  itself. As handling rods  68 , 70  begin to rotate, mold sections  12 , 14  need to be able to rotate freely on the respective bottom and upper segments  80 , 79  of tool  76  until pin  83  drops into notch  15 ′ and flange  19 ′ strikes tab  79 , respectively. To reduce friction at the anterior mold/tool interface, three dowels  85  are provided in annularly spaced relation about diameter d 2  of tool  76  (FIGS.  22 , 24 ), against which the top surface  15 ′ of anterior mold  12  rides when handling rod  68  begins to rotate. The frictional force at the posterior mold/tool interface is controlled by the amount of vacuum pressure applied through line V. 
     As discussed above, notch  15 ′ of anterior mold section  12  is formed directly opposite (180 degrees) the ballast axis of the mold surface  12 ′, and flange  19 ′ of posterior mold section  14  is formed directly opposite (180 degrees) the toric axis of the mold surface  14 ′. As such, with the anterior and posterior mold section  12 , 14  at their “home” positions, the location of the ballast and toric axes of the respective mold surfaces is known. 
     Referring to FIG. 6, once the anterior and posterior mold sections  12 , 14  have been rotated to their home positions, the anterior and posterior handling rods  68 , 70  are lowered and raised, respectively, thereby disengaging the mold sections  12 , 14  from the alignment tool  76 . Once the mold sections are clear of the alignment tool  76 , glider plate  72  retracts to the left, back to its home position seen in FIG.  6 . 
     In the preferred embodiment of the invention, to establish the desired axial offset between the toric and ballast axes, the anterior mold section  12  is rotated while the posterior mold section  14  remains stationary, although it is understood either one or both may be rotated to achieve the desired offset. Thus, at this point in the production cycle of machine  10 , computer  11  instructs anterior handling rod  68  to rotate itself together with anterior mold section  12  to the predetermined axial offset initially programmed into computer  11 . (See also FC 8  in FIG.  10 ). As stated previously, the axial offset may be programmed anywhere from 0 degrees to 180 degrees as required. For example, if toric lenses having an axial offset between the toric and ballast axes of 5 degrees is desired, this is keyed into computer  11  by the operator, and computer  11  will instruct anterior handling rod  68  to rotate 5 degrees at the appropriate time in the production cycle described above. 
     There may be a small amount of “backlash” in the rotation of anterior handling rod  68 , such that the home position of anterior mold section  12  deviates from the desired setting. The backlash may be caused by a light looseness in the drive belt  68 ′, for example. Therefore, in the preferred embodiment of the invention, the home position of the anterior mold section  12  is made 5 degrees minus the home position of the posterior mold section  14 . This allows to make up for any backlash by allowing 5 degrees of extra rotation for the anterior mold section  12  to reach the predetermined axial offset. Thus, the home position of the posterior mold section  14  is considered to be 0 degrees and the home position of the anterior mold section  12  is set at 5 degrees negative to the home position of the posterior mold section  14 . Thus, to reach an axial offset of 10 degrees, for example, the anterior handling rod  68  rotates the anterior mold section  12  in the clock-wise direction (i.e., toward 0 degrees) by a total 15 degrees if there is no backlash (i.e., if home positions of the posterior and anterior mold sections  12 , 14  are exactly 5 degrees apart). If there is backlash, for example, the home position of the anterior mold is only 4.5 degrees apart from the home position of the posterior mold section  14 , then the anterior handling rod  68  would rotate anterior mold section  12  by a total 14.5 degrees to reach an axial offset of 10 degrees, thereby compensating for the backlash. 
     Referring still to FIG. 6, once anterior mold section  12  has been rotated to the correct axial offset, a predetermined quantity of liquid monomer is injected into anterior mold section  12  via a monomer injection syringe  86 . (See also FC 9  in FIG.  10 ). Syringe  86  is movable along an axis z—z via a pneumatic control assembly  88 . Thus, syringe  86  is movable, via signals received from computer  11 , from its home (out-of-the-way) position seen in FIGS.  1  and  3 - 5  when not in use, to the extended position seen in FIG. 6 when injecting the monomer into the mold section  12 . Once the monomer has been injected into the mold section, the computer sends a signal instructing syringe  86  to retract to its home position. FIG. 1 shows the monomer station  90  which delivers the correct amount of liquid monomer through lines  92   a-c  to each of the three syringes  86  for filling each of the three anterior mold sections  12  at this time. 
     Referring now to FIGS. 7 and 8, monomer has been injected into the anterior mold sections  12  and syringe  86  has retracted to its home position. The posterior mold section  14  is now ready to be capped to the anterior mold section  12 . As described in detail above, the anterior and posterior mold sections  12 , 14  are at this point at the correct axial offset regarding the toric and ballast axes thereof. There is therefore no further rotation of either the anterior or posterior mold sections  12 , 14   a.  Thus, posterior handling rod  70  is now lowered and anterior handling rod  68  is raised until posterior mold section  14  carried thereby engages the respective anterior mold section  12 . (See also FC 10  in FIG.  11 ). The clamping force of the posterior mold section  14  on anterior mold section  12  is predetermined and precisely controlled by anterior handling rod  68 . Once the appropriate clamping force has been achieved, the vacuum line V in rod  70  is released and handling rod  70  is raised (FIG.  8 ), and anterior handling rod  68  is lowered, leaving the now capped mold sections  12 , 14  on anterior handling rod upper surface  68 ′. (See also FC 11  in FIG.  11 ). As seen in FIG. 2A, a pusher arm  92  is provided which is signaled at this time by computer  11  to extend in the direction of arrow  92 ′ a distance sufficient to push the three capped mold sets  14 , 16   a-c  out of housing  40  and onto a UV curing table  94  in the positions labeled  12 , 14   a′-c′ , where the mold sections are clamped with an external pressure during curing. (See also FC 12  in FIG.  11 ). A gate  96  may optionally be provided to maintain isolation between the UV cure table  94  and machine housing  40 , each of which may be provided with different atmospheric environments, if desired. Once the monomer has cured, the mold is de-capped and the molded toric lens is released from the mold. Further processing steps may be performed as desired (e.g., polishing, edging, packaging) in any known manner. 
     The above describes a single production cycle of machine  10 . Subsequent production cycles may be run continuously. As seen best in FIGS. 5 and 6, when anterior handling rod  68  is raised to engage anterior mold section  12  in tool  76 , glider plate  62  retracts to its home or “first stop” position S 1 . This is possible due to the open channels  61  (FIG. 2B) bridging anterior mold openings  62   a,c  and  e,  with posterior mold openings  62   b,d  and  f  in plate  62 , wherethrough anterior rod  68  passes when plate  62  is retracted. Thus, in step FC 6 , plate  62  has already retracted and has been re-loaded with anterior and posterior mold sections  12 , 14  in openings  62   a,c,e  and  62   b,d,f  thereof, respectively. Thus, once the capped mold sets  12 , 14   a-c  have been moved to UV cure table  94 , plate  62  is in position and ready to extend to position S 2  to begin the next production cycle.