Injection molding apparatus for producing a toric lens casting mold arbor

Injection molding apparatus for producing a lens coating mold arbor, said arbor having

• i. hollow top and bottom portions separated by a finished element;
• ii. exterior and interior lateral surfaces;
• and
• iii. a bottom end surface carrying at least one alignment means for aligning said arbor on a lathe;
• said injection molding apparatus comprising:
• a. a first molding body plate having an interior opening and serving as a base plate;
• b. a second molding body plate, located above said first plate, having an interior opening with a lateral surface corresponding to said exterior lateral surface of said bottom portion of said arbor, said interior opening in said second molding body plate being in registration with said opening in said first plate;
• c. a first core pin inserted in said openings of said first and second plates, said first core pin having an external lateral surface corresponding to said interior lateral surface of said bottom portion of said arbor, said first core pin being spaced apart from said lateral surface of said interior opening of said second molding body plate to provide a cavity having the shape of said bottom portion of said arbor;
• d. a third molding body plate, located above said second plate, having an interior opening with a lateral surface corresponding to said exterior lateral surface of said top portion of said arbor, said interior opening in said third molding body plate being in registration with said interior openings in said first and second plates;
• e. a toric core pin inserted in said interior opening of said third molding body plate, said toric core pin having a bottom end shaped in the form of a toric lens curve having a predetermined toric axis, said toric core pin having an exterior lateral surface corresponding to said interior lateral surface of the said top portion of said arbor, said toric core pin being spaced apart from said surface of said interior opening of said third molding body plate to provide a cavity having the shape of said top portion of said arbor, and said bottom end of said toric core pin being spaced apart from the upper end of said first core pin to provide a cavity having the shape of said finished element separating said top and bottom portions of said arbor;
• f. at least one alignment ridge formed in said toric pin for mating with a corresponding alignment slot in said third plate, whereby the toric axis of said toric pin is maintained in a stationary position;
• g. a rotatable ring plate inserted in said first plate for forming said bottom end surface of said arbor, said rotatable ring plate having an upper surface corresponding to said bottom end surface of said arbor and having at least one ridge in its said upper surface for forming an alignment slot in said bottom edge surface of said arbor;
• h. means for rotating and locking said rotatable ring plate at a point where said ridge in said ring plate is offset a predetermined number of degrees from the toric axis of said toric pin, whereby said alignment slot in said bottom end surface of said arbor will be offset a corresponding number of degrees from said toric axis;
• and
• i. means for introducing resinous molding material into said cavities and applying heat and pressure to said molding material to produce said lens casting arbor.