# US 5,345,725 A · Variable pitch lapping block for polishing lenses > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,345,725 A - Document ID: US5345725A - Status: Granted - Kind: A - Application number: 08/043,650 - Filed: 1993-04-06 - Granted: 1994-09-13 - Earliest claimed: 1993-04-06 - Inventors: Frank H. Anthony - Web page: https://patentgrep.com/patent/US5345725A ## CPC - B24B 13/005: Blocking means, chucks or the like; Alignment devices - B24D 13/00: Wheels having flexibly-acting working parts, e.g. buffing wheels; Mountings therefor - B24B: MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING (grinding of gear teeth B23F, of screw-threads B23G1/36; by electro-erosion B23H; abrasive or related blasting B24C; tools for grinding, buffing or sharpening B24D; polishing compositions C09G1/00; abrasives C09K3/14; electrolytic etching or polishing C25F3/00; grinding arrangements for use on assembled railway tracks E01B31/17); DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS - B24D: TOOLS FOR GRINDING, BUFFING OR SHARPENING (abrading-bodies specially designed for tumbling apparatus, e.g. abrading-balls B24B31/14; honing tools B24B33/08; lapping tools B24B37/11) ## Abstract A variable pitch lapping block for use in polishing a range of prescription lenses having different radii of curvatures is obtained by the use of an element made of rubber or the like, which is associated with a pressurized chamber, wherein the element exhibits a range of curvatures depending upon the variation of the pressure in the chamber. ## Claims ### Claim 1 A variable pitch lapping block for use in polishing optical lenses in an apparatus for polishing lenses having any one of a plurality of radii of curvatures, said lapping block comprising: a rigid lapping block body element having a top portion structured for attachment to said apparatus and outer side walls extending downward and away from said top portion for forming an upper portion of a chamber, a resiliently elastic element having edges and a radius of curvature between the edges, said edges being attached at said side walls to form a closure for said chamber, and a valve element extending through a side wall of said rigid lapping block body element and communicating with said chamber for admitting pressurized fluid into said chamber for changing the radius of curvature of said resilient elastic element to conform to a selected one of said plurality of radii of curvatures of said lenses. ### Claim 2 (depends on 1) A variable pitch lapping block as in claim 1 wherein said resiliently elastic element is adhesively attached at said edges to the side walls of said lapping block body element. ### Claim 3 (depends on 1) A variable pitch lapping block as in claim 1 wherein said resiliently elastic element is attached to said side walls by clamp means. ### Claim 4 (depends on 1) A variable pitch lapping block as in claim 1 wherein said resiliently elastic element includes an upper portion extending along said upper portion of said chamber. ### Claim 5 (depends on 1) A variable pitch lapping block as in claim 1 wherein said lenses are prescription lenses to which the radius of curvature of said resiliently elastic element conforms. ### Claim 6 (depends on 5) A variable pitch lapping block as in claim 5 wherein the radius of curvature of said resiliently elastic element is expanded by fluid pressure in said chamber to a radius of curvature of one of said plurality of radii of curvatures of said lenses so as to uniformly polish a lens surface to a prescribed radius of curvature. ### Claim 7 (depends on 6) A variable pitch lapping block as in claim 6 wherein a slurry of grinding compound is placed between said resiliently elastic element and said lens surface for polishing said surface. ### Claim 8 (depends on 1) A variable pitch lapping block as in claim 1 wherein said fluid is air. ### Claim 9 (depends on 1) A variable pitch lapping block as in claim 1 wherein said rigid lapping block body element is made of metal or plastic. ### Claim 10 (depends on 1) A variable pitch lapping block as in claim 1 wherein said resiliently elastic element is made of rubber. ### Claim 11 (depends on 1) A variable pitch lapping block as in claim 1 wherein said outer side walls extend from said top portion to form a hollow open ended upper portion of said chamber. ### Claim 12 (depends on 1) A variable pitch lapping block as in claim 1 wherein said side walls extend to a lower planar surface of said body element. ### Claim 13 (depends on 12) A variable pitch lapping block as in claim 12 wherein said resiliently elastic element includes an upper planar surface attached to said edges and said upper and lower planar surfaces are attached to each other. ### Claim 14 (depends on 1) A variable pitch lapping block as in claim 1 wherein said resiliently elastic element includes two or more sections each made of material having different hardnesses. ### Claim 15 (depends on 14) A variable pitch lapping block as in claim 14 wherein said material is rubber.