US1201833A - Lens grinding and polishing machine. - Google Patents

Description

I. J. LANDE.

LENS GRINDING AND POLISHING MACHINE.

APPLICATIO N FILED JAN- 26, I914.

on V W M m P Y J b WW a? 3 l t 3 E 8 L aflv f 0 1 E ma, 1 .ll 1

I. J; LANDE. LENS GRINDING AND POLISHING MACHINE.

Patented Oct'17', 1916.

2 SHEETS-SHEET 2 APPLICATION HLED JAN- 26, 1914.

WINNIE-- WWNEEEJE: 'llf a ATTU NEY:

rsanoan a. m nor, or BUFFALO, NEW YORK.

LENS GRINDING AND POLISHING MACHINE.

assists.

Specification of was Patent,- t t (mt, 17,' 191 Application filed January 26, 1914. Serial No. 814,353.

To all whom itmay concern 'I Be it known that I,- Isabonn J. LANDE, a

citizen of the United States, residing at Buffalo, inthe county of Erie and State of New 'York," have invented new and useful Improvements in us Grinding and Polishf ing, Machines, of which the followingis a- 4 i specification; vention relates to a machine for and polishing toric and other lenseshavmg compound curvatures.-

In machines as ordinarily constructed, a

lens-holder or chuck. is employed in connection? with a i15fgrinding'pad having its face previously curvatiues, entailing considerable expense.

ground or shaped to the desired curvature of" the leis. This'arrangement requires the useof separate pads for different radii or jMoreover, if the pad contains imperfections .ie'r wears unevenly, which is often the case,

F -One of the as;

thejcurve' impartedto the lens is incorrect sirinaccurate.

objects of myinvention is the production of a grin chine arias character which the correct 1| dingof the lenses is not dependent on the erfection ofihe grinm'ng pad or the accur'ate curvatnrcf'f its grinding face, but which accurate predetermined curvature or.

is-"soorgan'med that it. will grind lenses to radius regardless of imperfections of the grinding pad and without the necessity of .arnplo numerous pads with different eurvatures, thus efiecting an important sav- 4 mg A further object is the construction of a simple machine of this kind which can be f readily adjusted to grind toric lenses to.

curves of different radii as required.

Another object is to improve the "con 1 is a sectional side elevation of the machine showing the parts in the same position.

Fig. 3 1s "asectional top plan view thereof. Fig; i is a fragmentary front QlGVtltlOllQf the machine showing the grinding pad in position to d convex lenses. Fig. is a .face'view of'the lens-holder or'chuck. Figs.

relatively-stationary ding and'polishmg ma permit of'this action. The chuck is 6, 7 and 8 are diagrammatic views illustrat-.

ing different adjustments of the chuck for producing curvatl res of different radii. Snmlar charac ers of reference indicate corresponding parts throughout the several views.

and 3 is the main driving shaft of the machine journaled horizontally. in the frame.

" Arranged above the table 2 is the rotary work or lens-holder or chuck 4 which is preferably'cylindrical, or in the form of a drum, and to the cylindrical rim of which the lens-blanks 5 arc/adapted to be attached by pitch or any other suitable'cement, the blanks being cemented either to the inner or the outer side of the rim to produce concave or convex lenses. In some cases the lens-blanks may be cemented directly to the rim of the chuck, but in grinding concavelenses a number of interchangeable lens-carrying rings of different thicknesses l indicates-the upright frame of a ma chine on which is mounted a bed or-table 2,

are preferably employed, one of which is shown in the drawings and designated 6 This ring may be removably secured in the chuck by any suitable means.

In the'construction shown, the chuck is cast in one piece, and its rim is split or di- -vided transversely at diametrically-opp0- site sides, as shown at 7 the split portions thereof being connected by clamping bolts 8, so that by tightening or loosenin 'these boltsthe lens-carrying ring 6 is c amped therein or'released. The" split the chuck-rim? have sufficient e asticit to ortions of to the front end of a horizontal shaft 9 journaled in a bearing 10 carried by a slide or carriage 11 which is mounted to slide transversely of said shaft on a standard 12. The latter rises from a horizontally-swinging or oscillatory arm 13 arranged above the table 2 and fixed to the upper end of an upright rock shaft 14 which turns in suitable bearings on the table 2 .and the frame 1, and extends through and below said table. This shaft is actuated by any suitable .means, the preferred means consisting of a rock arm 15 secured to its lower end and having a pin 16 which engages. a

grooved rotary cam 17 mounted loosely on the main shaft 3. A suitable clutch 18 serves to throw this cam into and out ofgear with said main shaft which'is adapted The chuck carriage 11 may be adjusted.

on the standard of the oscillating arm 13 by a horizontal screw 22, such as commonly used for adjusting lathe stocks, or by any other suitablemeans. The carriage is also provided with a set screw 23 for retaining it in position. Rotary motion is imparted from the main shaft 3 to the chuck by a sprocket chain 24 passing around sprocket wheels 25 and 26 secured to the chuck-shaft 9 and the hub of the cam 17. This chain may be provided with a suitableibelt tightener27. 1

Referring to the concave grinding machine shown in Figs. 1, 2 and 3,28 indicates' the grinding pad mounted in a suitable holder 29 swiveled by a horizontal pivot 30 to 'the end of a horizontal arm or bracket 31. This bracket extends into the hollow chuck and has a shank 32' arranged at right angles to the axis of the chuck and clamped to the horizontal head of a support or standard 33 by a bolt 34 passing through a longitudinal slot 35 of said shank. By

this construction, upon loosening the clamping bolt 34, the pad can be adjusted toward or from the inner face of the chuck-rim toaccommodate the same to lens-cariwing rings 6 of different thicknesses. To prevent the bracket 31 from swinging laterally on the bolt 34, a pair of clampingscrews 34 bear against opposite edges of the slotted shank, as shown in Fig. 3, these screws being arranged in perforated lugs carried by the standard 33.

The pad-supporting standard 33 is pivoted at its lower end to a base-plate or car-' riage 36 by a pin 37 normally arranged parallel with the axis of the rotary chuck 4, so that said standard may swing at right angles to said axis to permit the grinding pad to approach and recede from the inner face of the chuck-rim. Bearing against the rear side of this standard isa pressure-arm 38 also pivoted at its lower end to the baseplate 36 bya pin 39 arranged parallel with the pin 37 and preferably carrying an antifriction roller 40 which bears against a boss 41 of the standard 33. This arm carries an overhanging weight 42 whereby a constant pressureis exerted against the standard 33 which in turn presses the grinding pad against the lenses of the chuck,- in a manner common to this class of machines. The forward movement of the standard 33 is liniited by a suitable stop which preferably .consists of a screw 43 hearing against the This base plate may be clamped in position by a vertical screw or bolt 46 journaled in the table 2 and having a handle. 47, said plate being provided in its front edge with a notch 48 which receives said screw, as shown by dotted lines in Fig. 3. Other suitable means may however be employed for this purpose. If desired, the hub of the base-plate may be provided with an additional clamping screw 49 which engages the pivot pin 45.

In'addition to the pad-support or standard 33, the machine is preferably provided with a supplemental standard 50, of substantially the same construction, arranged to face the outer side of the cylindrical chuck-rim, as best shown in Figs. 1 and 4, to support and hold a grinding pad 28 for grinding convex lenses. In this case, the pad-bracket 51 is slotted like the bracket 31 and adjustably secured to the top of the standard 50, as in the first described support by clamping bolts 52 and 53, but as the pad is applied to the outer side of the chuck, the bracket is straight and arranged radially of the chuck. The standard is pivoted .to swing toward and from the chuck, itslower end being hinged by a pin 54 to a fixed base 55 mounted on the table 2.

Like the first-described pad support, this supplemental support 50 has a pressure arm 56 carrying an overhanging weight 57 and an adjustable stop 5-8.

The operation of the machine is iias follows: l/Vhen lenses are to be ground concave, the lens-blanks are cemented to the inner face of a lens-carrying .ring6 of the required thickness to produce a vertical curvature of the prescribed radius. drawing the grinding pad from the chuck, said ring is, inserted in the chuck and clamped therein by tightening the bolts 8, after which the grinding pad is returned to its normal position within the chuck, these movements of the pad being effected by swinging the carriage or base plate 36 away from or toward the chuck, as hereinbefore described. Upon now setting the machine in motion, the chuck 4 is constantly rotated on its axis and at the same time bodily oscillated by the rocking movement of the shaft 14 produced by the rotary cam 17. The chuck is thus oscillated on an axis arranged After withsubstantially at right angles to its own axis of rotation, with the result that-this oscillating motion of the chuck in a horizontal plane relatively to the stationary "grinding pad causes the lenses to be ground to th desired horizontal curvature, while therotary motion of the chuck causes them to be ground to the desired vertical curvature. Obviously, the chuck oscillates in a predetermined arc with reference to the face of the grinding pad and the radius of the horizontal curve to which the lens is groimd therefore remains constant and accurate,

2 even if the pad has an imperfect surface or develops imperfections by wear. 7

Variations in the radius of the vertical curve of the lenses are obtained by changing the distance between the axis of the chuck and-the face of the lenses.

6- of different thicknesses, as

This may be done by using separate lens-carrying rings, hereinbefore described, but if desired, the pitch bed in a the lenses are obtained by lengthening or shortening the radius of which the len'sesare seated may be thinned or thickened for this purpose.

Variations in the horizontal curvature of oscillation of the chuck, or in otherjwords, varying the distance between the axis of the rock shaft 14 and the inner face of the chuck-rim, which is accomplished by, shifting the chuck 4' laterally on the standard 12 of the oscillating arm 13 by means of the carriageadjustin screw 2-2, the pad-bracket 31 being1 adjuste accordingly. This action'will be c early understood by referenceto Figs. 6, 7 and 8, where the dotted vertical line A indicates the axis of oscillation of the chuck and the distance or radius from dotted line B the said axis to the concave faces of thelenses. In Fig.6. the axis of rotation of the chuck is coincident with its axis 'A'of oscillation,

' circular To increase or diminish and in this adjustment the vertical and horizontal curves of the lenses are ground to the same radius, producing spherical lenses.

horizontal curvature of the lenses for producing toric lenses, the chuck is shifted laterally to either side of the central position shown in Fig. 6, the chuck being shifted toward the right from said central posit on to increase said radius, as shown in Fig. andtoward the left from said central position to shorten said radius, as shown in Flg. 8. In-either case, this. adjustment can be readily and accurately effected by means of Convex;

the carriage-adjusting screw 22. spherical and toric lenses can be likewise ground and polished by chine as shown-in Fig. 4.

' It is a characteristic tion that the lens-blanks are applied to the v cylindrical chuck wall or rim of the or lens-holder 4 and that the iatter has two motions with reference'to the relatively-star.-

the radius of they carriage and coiiperating with adjusting the mafeature of my inven chlne,'.the combination of a relatively-staalent motion about its axis and an oscillatory motion on an axis substantially at right angles to its axis of IOttfllOIl. By this comparatively simple" expedient or compound motion of the chuck, the machine is caused to grind both curvatures of toric or other compound lenses with the utmost accuracy, regardless-of the shape of the face of-the grinding pad or inequalities-of its texture or other imperfections. At the same time, this construction efi'ects an important sav-' ing, in that it avoids the necessity of employing a plurality or variety of grinding pads, each having a grinding face of predetermined and previously-ground contour, as in ordinary lens-grinding machines in which one of the two curvatures of toric or other compound-lenses is produced by the curve.- ture of the grinding-padand therefore depends for its correctness upon the accuracy of the face of the pad and the maintenance of such accuracy throughout the grinding. operation of the lens.

I claim as my invention:

1. In a lens-grinding or polishing machine,.the combination of a cylindrical lensholder adapted to carry the lens-blanks on its cylindrical wall, said holder having a its axis of oscillation being substantially at right angles to its axis of rotation, means for actuating the holder, and a relatively-stationary grinding pad having its grinding" surface arranged to face the cylindrical wall of the lens-holder.

2. In a'lens grinding or polishing machine, the combination of a relatively-sta-' tionary grinding pad, a rotary cylindrical cillation to increase or diminish the radius of the lens-curve produced by such oscillatory motion, and means for actuating the lens-holder. I

3. In a lens-grinding or polishing machine, the combination of a relatively-stationary grinding pad, an oscillatory memher, a carriage adjustable on said member in a plane transversely of its axis of oscillation, a rotary lens-holder mounted on said said pad, said lens-holder having its axis arranged substan-v tially at right angles to said axis of oscillation, and means for actuating said member. and the lens-holder.

4. In a lens-grinding or polishing mationary grinding pad, a rock shaft carrying an arm. a carriage adjustable on said arm in a plane transversely of its axis of oscillacompound rotary and oscillatory motion and tion, a rotary lens-holder mounted on said carriage and coperating with said pad, and means for actuating said rock shaft and the lens-holder. a

5 5. In a lens-grinding or polishing 11121- chine, the combination of a relatively-stationary grinding pad, a rock shaft carrying an arm, a cam for actuating said shaft to 05;-

illate said arm, arotary 1ens-h0lder mount- 10 ed on said arm with its axis substantially at right angles to the axis of said rock shaft, and means for actuating said shaftand the lens-holder.

Witness my hand this 24th day of January, 1914C.

ISADORE J. LANDE.

Witnesses:

LOUIS SGHULMAN, C. F. GEYER.

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