US1471351A - Lens - Google Patents

Description

A. PEI-LOW LENS Filed April 4, 1921 PRIOR ART PRIOR ART 5 V I \QM H Patented Oct. 23, 1923. V

UNITED STATES PATENT OFFICE.

ARTHUR PELLOW, OF SOUTHBRIDGE, MASSACHUSETTS, ASSIGNOR TO AMERICAN OP- TICAL COMPANY, OF SOUTHBRIDGE, MASSACHUSETTS, A VOLUNTARY ASSOCIA- TION OF MASSACHUSETTS.

Application filed April 4, 1921. Serial No. 458,242.

To all W110!!! it may concern: Figure VII represents a plan view of a 55 Be it known that I, ARTHUR PELpow, a slightly modified construction.

citizen of the United States, residing at Prior to my invention it has been custoiu- Southhridge. in the county of \Vorcester ary to produce blanks for the manufacture and State of Massachusetts, have invented of ophthalmic lenses by moulding the glass certain new and useful Improvements in substantially to the desired for1n thus re- 50 Lenses, of which the following is a speciducing to a minimum the subsequent grindfication. ing necessary. Difficulties. however, have This invention relates toimprovements in been experienced due to the fact that. the

lenses and has-particular reference to blanks edge of the mold plunger 1 tends to wear for use in the production of ophthalmic slightly as at 2, so that as it presses against 65 lenses. the glass stock 3 in the mold 4 a slight fin 5 Prior to the present invention difficulties is formed around the edge of the blank.

have been experienced in connection with This tin is objectional since while of relathe molding of ophthalmic lens blanks due tively thin formation it tends if broken ofl to the formation of a slight fin or ridge to break down an adjacent portion of the 7 about the edge of the blank. It is, therefore, glass rendering it liable to chip, and preone of the primary purposes of the present vents the blank properly fitting on the invention to provide a novel and improved grinding tool for initial grinding, renderblank construction which shall eliminate the ing the edge liable to be broken as the difficulties hitherto experienced on account grinding starts, entailing the possibility of 75 of the formation of such fin. 1 slightly tilted grinding, and introducing A further object of the present invention certain prismatic effect in the lens. It has is the provision of a novel and improved hitherto been necessary to bevel off the edge construction Which shall make it possible as indicated at; 6 in Figure III, this result:

tov eliminate preliminary treating of the ordinarily being accomplished by the lens blank before grinding, which shall insure being held by hand against the edge of a proper engagement between the grinding rotating stone which will grind down the tool and blank when being ground and rib 5. This, of course, adds considerable to 30 eliminate all liability of chipping of the the cost of production of the blanks and is blank at the edges. a relatively unnecessary operation.

Other objects and advantages of my im- I have, therefore, provided my improveproved construction should be readily apment in structures of this character, which parentby reference to the following speciconsists in molding on the face of the blank 35 fication taken in connection with the accomspaced inwardly somewhat from the edge panying drawings. and it will be understood the annular rib 7, as shown in Figure V, or

that I may make any modifications in the theseries of [)IOJECtiOHS 8 as shown in Figspecific features hereinafter disclosed withure VII, the two being substantially equivain the scope of the appended claims without lents, in that in either event the projections departing from or exceeding the spirit of are high enough so that they will contact my invention. with the grinding tool 9 before the fin comes Figure I represents a plan view of a blank into engagement with the tool so that the embodying my improvements. initial grinding is a grinding away of these Figure II represents a sectional view of a projections 7 or 8, which while a relatively 4 prior art construction. rapid process is sufficiently slow to allow Figure III represents a similar view of the fin being evenly ground off and withshowing a subsequent step in the production out danger of breakage, as would be the case of such prior art construction. were the pressure of the grinding operation Figure IV illustrates the moulding of a all exerted against the uneven fin.

prior art blank. By my improved construction, therefore,

Figure V represents a sectional view I provide a blank making it unnecessary to through mv improved blank. first edge or chamfer the molded blank, and Figure is a sectional view illustrating also provide the rim 7 or steadying projecthe use of my blank. tions 8, which are so spaced and related that they will correctly position the blank on the block without tilting and will allow the blank to move down gradually into en agement with the grinding tool so that a] 1nequalities produced by moulding are properly removed and liability of incorrect tilting and production of prism in the finished lens on account of tilting reduced to a minimum.

I claim:

1. As an article of manufacture, a lens blank having integral means formed on the face thereof for initial engagement with a grinding tool, said means being disposed intermediate the center and edge of the lens and positioned to balance the lens on the grinding tool at the start of the grinding operation.

2. As an article of manufacture, a lens blank having near the edge thereof a portion projecting from the face of the blank for engagement with the grinding tool face prior to engagement between the grinding tool face and an annular fin which forms on the edge of the lens when molded, whereby the blank may balance on the grinding tool face at the start of the grinding operation.

3. As an article of manufacture, a moulded blank having on its face an integral annular rib s aced inwardly from and substantially con orming to a tin, which forms on the lens edge when molding the lens, the construction and arrangement of the rib being such as to balance a lens on the grinding tool face.

4. As an article of manufacture, a molded lens blank provided with means integral with one face of the lens and located intermediate the center and edge of the lens. the construction and arrangement of said means being such that it may contact with the grinding tool face prior to engagement between the grinding tool face and a tin which usually forms on the lens blank when molding the same, thereby acting to balance a blank on the grinding tool face.

In testimony whereof I have affixed my signature, in presence of two witnesses.

ARTHUR PELLOW. Witnesses:

Amen G. HAsKELL, SUSAN CASAZZA. f

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