US3704558A - Lens block - Google Patents

Lens block Download PDF

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Publication number
US3704558A
US3704558A US118318A US3704558DA US3704558A US 3704558 A US3704558 A US 3704558A US 118318 A US118318 A US 118318A US 3704558D A US3704558D A US 3704558DA US 3704558 A US3704558 A US 3704558A
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US
United States
Prior art keywords
lens
block
passageway
blocking material
cavity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US118318A
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English (en)
Inventor
George M J Sarofeen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Coburn Manufacturing Co Inc
Original Assignee
Coburn Manufacturing Co Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Coburn Manufacturing Co Inc filed Critical Coburn Manufacturing Co Inc
Application granted granted Critical
Publication of US3704558A publication Critical patent/US3704558A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B13/00—Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor
    • B24B13/005—Blocking means, chucks or the like; Alignment devices

Definitions

  • Lens blanks are blocked for purposes of providing a means by which the lens blank is chucked into a lens processing apparatus such as a lens grinding and polishing machine.
  • a lens block generally includes a concave surface on one side for receiving the convex surface of the lens to be treated or processed, and a body portion on the other side including a chucking surface having recesses therein for purposes of centering the block and the attached lens in a processing apparatus.
  • Conventional practices include molding or casting the lens block from a low-melting point alloy or the like directly onto the convex surface of the lens blank.
  • the lens blank may or may not be provided with a suitable coating to facilitate the release of the block from the blank after the processing thereof is finished.
  • a lens blocking device which will permit the lens blocking agent to freeze uniformly so that the heat and pressure from the blocking agent will not cause zonal aberrations in the plastic lens being blocked.
  • alloys there are two types of alloys that can be used, one which shrinks and the other type that expands. This invention is directed particularly toward the expandable type and it is a particular object of this invention to control the pattern of pressure exerted on the plastic lens blank upon expansion of the blocking agent during freezing.
  • Beasley attempts to solve the problem of uneven shrinkage by providing a uniform layer of blocking material, which layer is created by placing a surplus of pitch or other bonding material between the blank and blocking body and then pressing the lens blank against the blocking body.
  • the surplus pitch is forced outwardly between a plurality of gaps around the periphery of the block, which gaps define spaced lens blank supporting ledges. This process is particularly messy and involves an uneconomical usage of blocking material.
  • the Beasley patent the total area of support for the lens blank is somewhat lessened. Further, in the Beasley patent, there is no systematic method of placing the pitch between the lens blank and the lens block such that the air pockets which create uneven pressure areas are eliminated.
  • a lens block having a front side and a rear side, with the front side being concave in configuration to receive the convex surface of a lens block to be processed.
  • the rear side is provided with means for mounting the block onto a lens blank processing apparatus.
  • the front side of the block is provided with a lens supporting ledge circumscribing a concave surface for supporting a lens blank in spaced relationship to the concave surface to define a uniform thickness, blocking-material receiving cavity between the lens blank and the lens block.
  • a blocking material inlet extends axially of the lens block and communicates the cavity to a suitable blocking material reservoir and injection apparatus.
  • the lens-supporting ledge is provided with a first groove or passageway therein and a second groove or passageway diametrically opposed to the first groove, with the second groove being of a substantially less cross-sectional diameter than the first groove.
  • FIG. 1 is a perspective view showing the lens block of this invention in position on a lens blocking apparatus
  • FIG. 2 is a plan view of a lens block of this invention.
  • FIG. 3 is a cross sectional view taken along lines 3-3 of FIG. 2 showing in phantom the positioning of a lens blank thereon.
  • FIG. I the lens block is shown in position on a lens blocking apparatus 12 which is of a type disclosed in US. Pat. No. 3,468,366, dated Sept. 23, I969, to Jack M. Suddarth, entitled LENS BLOCKER.
  • the lens blocking apparatus is provided interiorly with a reservoir of molten, low-melting point alloy which is injected by a suitable hand pump, not shown but disclosed in the abovementioned patent, into the uniform-thickness cavity 14 between the lens blank 16 and the lens block 12. It is to be noted that the lens block, and, therefore, the lens blank are supported in an inclined or angulated attitude.
  • the lens block includes a front side having a concave surface 18 and a lens-supporting ledge 20.
  • the lenssupporting ledge is slanted to receive and conform to the convex surface of the lens blank 16 and is raised above the concave surface 18 such that the lens blank defines a cavity with the concave surface 18 when it is seated on the ledge 20.
  • the rear side 22 of the lens block is provided with centering recesses 24 which serve to align the lens block in a lens processing apparatus when it is chucked therein.
  • a conduit 26 extends axially of the lens block and communicates the cavity 14 with the blocking material reservoir. It is through this passageway that the lens blocking material is injected into the cavity 14.
  • the ledge is provided with diametrically opposed grooves 28 and 30 which, along with the surface of the lens blank resting on the ledge, defines a passageway communicating the cavity with the atmosphere.
  • the groove 28 is considerably smaller than the groove 30 in cross-section, with the size of the groove 28 being sufficient to permit the egress of air but not of the blocking material.
  • blocking material is injected through passageway 26 and into cavity 14, and, due to the inclined attitude of the block and the lens blank supported thereon, the material first flows downwardly toward the smaller groove 28 and pushes air from the cavity out through the groove 28.
  • the groove however, as mentioned above, is so small that the blocking material cannot pass therethrough.
  • the low-melting point alloy then freezes and seals the opening 28.
  • Continued injection of the blocking material into the cavity 14 causes the level of the material to rise toward the larger opening 30 pushing air outwardly through the opening 30 and eventually extruding through the opening 30 to indicate that the cavity is filled.
  • the thickness of the cavity 14 is constant throughout and the lens block is of such dimensions that it supports substantially the entire area of the lens blank.
  • any undue pressures instead of being forced against the lens blank surface, will be absorbed by the material in the inlet passageway 26. In other words, the material in the cavity will flow back through the passageway 26. In this manner, the passageway 26 acts as a pressure absorber. It can be seen that by using the lens block of this invention in the manner described, a uniform layer of blocking material will be for ed wi out exerting undue pressures against the su ace of t e plastic lens blank. The probability of creating zonal aberrations in the lens blank will be minimized.
  • a lens block for use in lens blank processing apparatus wherein said lens block is angularly disposed comprising front and rear sides, a concave surface on said front side and means on said rear side for mounting said block on lens blank processing apparatus, a lens supporting ledge circumscribing said concave surface for supporting a lens blank in spaced relationship to said concave surface to define a blocking material receiving cavity, conduit means communicating said front and rear sides and providing an inlet for blocking material to said cavity, a first passageway in said ledge leading from said chamber to the exterior of said block, and a second passageway of smaller cross-sectional dimensions than said first passageway in said ledge diametrically opposite said first passageway and leading from said chamber to the exterior of said block, said block when mounted on said apparatus is angularly positioned to define upper and lower portions with said second passageway being in said lower portion.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
US118318A 1971-02-24 1971-02-24 Lens block Expired - Lifetime US3704558A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US11831871A 1971-02-24 1971-02-24

Publications (1)

Publication Number Publication Date
US3704558A true US3704558A (en) 1972-12-05

Family

ID=22377858

Family Applications (1)

Application Number Title Priority Date Filing Date
US118318A Expired - Lifetime US3704558A (en) 1971-02-24 1971-02-24 Lens block

Country Status (7)

Country Link
US (1) US3704558A (enrdf_load_stackoverflow)
JP (1) JPS5520822B1 (enrdf_load_stackoverflow)
BE (1) BE779818A (enrdf_load_stackoverflow)
CA (1) CA958426A (enrdf_load_stackoverflow)
DE (1) DE2208444A1 (enrdf_load_stackoverflow)
FR (1) FR2131970B1 (enrdf_load_stackoverflow)
GB (1) GB1386441A (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4899542A (en) * 1987-07-31 1990-02-13 Honda Giken Kogyo Kabushiki Kaisha Control device for a continuously variable transmission for motor vehicles
US5115553A (en) * 1982-05-14 1992-05-26 The Cooper Companies, Inc. Contact lens manufacturing apparatus
EP0484036A3 (en) * 1990-10-29 1992-08-05 Pilkington Visioncare Inc. Reinforced thermoplastic components for use in the manufacturing of ophthalmic lenses and methods of making such components
US5177907A (en) * 1991-11-12 1993-01-12 Summitt Molding & Engineering, Inc. Plastic lens block with ribs
US5210695A (en) * 1990-10-26 1993-05-11 Gerber Optical, Inc. Single block mounting system for surfacing and edging of a lens blank and method therefor
US5269102A (en) * 1991-06-19 1993-12-14 Gerber Optical, Inc. Disposable lap blank
US5520568A (en) * 1992-07-17 1996-05-28 Minnesota Mining And Manufacturing Company Method of processing a lens and means for use in the method
US5649856A (en) * 1995-12-13 1997-07-22 Coburn Optical Industries, Inc. Tear-away block for an ophthalmic lens
US6110016A (en) * 1998-06-22 2000-08-29 Ppg Industries Ohio, Inc. Lens block and method of processing lenses
US11086141B2 (en) 2018-03-23 2021-08-10 Carl Zeiss Vision International Gmbh Spectacle lens blank, and method and device for producing a spectacle lens from a spectacle lens blank

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3140568A (en) * 1963-02-28 1964-07-14 Univis Inc Lens blocking device
US3353307A (en) * 1964-10-29 1967-11-21 Titmus Optical Company Inc Lens holder for metallic blocking system
US3355342A (en) * 1965-02-26 1967-11-28 Armorlite Lens Company Inc Method of supporting lens blanks for grinding and polishing
US3383808A (en) * 1965-05-25 1968-05-21 Lunette De Paris Inc Lens block

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3140568A (en) * 1963-02-28 1964-07-14 Univis Inc Lens blocking device
US3353307A (en) * 1964-10-29 1967-11-21 Titmus Optical Company Inc Lens holder for metallic blocking system
US3355342A (en) * 1965-02-26 1967-11-28 Armorlite Lens Company Inc Method of supporting lens blanks for grinding and polishing
US3383808A (en) * 1965-05-25 1968-05-21 Lunette De Paris Inc Lens block

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5115553A (en) * 1982-05-14 1992-05-26 The Cooper Companies, Inc. Contact lens manufacturing apparatus
US4899542A (en) * 1987-07-31 1990-02-13 Honda Giken Kogyo Kabushiki Kaisha Control device for a continuously variable transmission for motor vehicles
US5210695A (en) * 1990-10-26 1993-05-11 Gerber Optical, Inc. Single block mounting system for surfacing and edging of a lens blank and method therefor
EP0484036A3 (en) * 1990-10-29 1992-08-05 Pilkington Visioncare Inc. Reinforced thermoplastic components for use in the manufacturing of ophthalmic lenses and methods of making such components
US5269102A (en) * 1991-06-19 1993-12-14 Gerber Optical, Inc. Disposable lap blank
US5177907A (en) * 1991-11-12 1993-01-12 Summitt Molding & Engineering, Inc. Plastic lens block with ribs
US5520568A (en) * 1992-07-17 1996-05-28 Minnesota Mining And Manufacturing Company Method of processing a lens and means for use in the method
US5649856A (en) * 1995-12-13 1997-07-22 Coburn Optical Industries, Inc. Tear-away block for an ophthalmic lens
US6110016A (en) * 1998-06-22 2000-08-29 Ppg Industries Ohio, Inc. Lens block and method of processing lenses
US11086141B2 (en) 2018-03-23 2021-08-10 Carl Zeiss Vision International Gmbh Spectacle lens blank, and method and device for producing a spectacle lens from a spectacle lens blank

Also Published As

Publication number Publication date
JPS5520822B1 (enrdf_load_stackoverflow) 1980-06-05
CA958426A (en) 1974-11-26
FR2131970A1 (enrdf_load_stackoverflow) 1972-11-17
BE779818A (enrdf_load_stackoverflow) 1972-06-16
GB1386441A (en) 1975-03-05
FR2131970B1 (enrdf_load_stackoverflow) 1973-06-29
DE2208444A1 (de) 1972-09-28

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