US881646A - Machine for grinding lenses. - Google Patents

Description

No. 881,646. PATENTED MAR. 10,1908. 0. G. ALLEN.

MACHINE FOR GRINDING LENSES.

APPLICATION FILED MATH. 1906.

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'W/T/VESSEJ I I m vmrm JAMMW I I m z q No. 881,646; PATENTED MAR. 10, 1908.

G. G. ALLEN.

MACHINE FOR GRINDING LENSES.

APPLICATION FILED MAY 16. 1 6.

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ULILE o. ALLEN, or cIIIoAco, ILLINOIS, ASSIGNOR TO FJA. HARDY & COMPANY, OF cHIoAso,

ILLINOIS, A CORPORATION OF ILLINOIS.

IMACHINE FOR GRINDING LENSES.

Specification of Letters Patent.

'Patented March 10,1908.

, Application filed May 16,-1906. Serial Nb. 317,052.

lng had to the accompanying drawings, form- 'mg a part thereof.

The purpose of this invention is to provide an improved mechanism for the purpose of desired form for use.

' grinding lenses, for eye-glasses or other'purposes, liavin diflerent portions of the area ground for d1fierent focal distances so as to produce, in one piece, and without abrupt shoulder or offset bet-ween the two areas, lenses for eye-glasses adapted for use at both long and short range.

The invention consists in thefeatures of construction and combination set out in the claims.

In the drawings':Figure 1 is a side elevation of a machine embodying this invention. Fig. 2 is a plan View of the same with the table in dpart broken away. Fig. 3 is a forward en elevation with the base of the standard broken away. Fig. 4 is a partly sec-- tional, detail elevation of certain of the operating parts at the forward end above the table, section being made axially with res ect to the lap carrier. Fig. 5 us a detail e evation of the power-communicating devices viewed from the rear end. Fig. 6 is an ax1al section of a portion of a lens operated u on 111 the machine. Fig.'7 is a' plan view o the lens showing diagrammatically the manner of cutting the same to produce the Fig. 8 is a detail section at the line 8-8 on Flg. 5.

To assist in readily. understanding the mechamsm shown in the drawings and hereinaft'er fto be described, the method and principle of the rst explained.

A blank of suitable glass for the lens, which has been, by any convenient means produced in or reduced to an. outline A approximating that to which it is to be brought y the use of the machine, is mounted for rotation by cementmg it or causing it in any proper manner to become adherent toa rotating carrier, and at the side to be dressed is exposed to the action of suitably shaped grinding or polishing' devices which comprise two parts,-to

wit, an annular lap whose operating face is present invention may .be,

shaft a pulley, 5, by means of a belt, 6, drives.

' form of the interior or secondary portion of the lens. The interior or supplemental lap does-net occupy the full opening of the annular lap, but is annularly spaced therefrom. Means are provided for relatively adjusting the two laps, first, for grinding by relative axial movement to keep their operating faces roperly related to produce a continuous ace on the lens, and, second, for olishing, so that their relative pressure may evaried at will. Between the lens carrier and the lap carrier there is provision for-relative oscilla- 7 5 tion while both are rotating, the ran eof oscillation' being substantiall the widt of'thle annular interval between t e twoelements of the lap, so that the inner or su 'plemental area oi the lens to be dressed by 't e-inner or $0 supplemental lap has a diameter greater} than that of the inner lap by the amount of the oscillation; and, similarly, the width of the outer annular area dressed by the outer annular la la by t e amount of half that oscillation.

T is statement of result assumes absolutely accurate construction and movement of the parts; but the slight variation from accuracy which may be allowed ma be compensated by equally slight increase 0 the range of oscillation beyond the width of the annular interval between the two laps, so that practically the two areas do not intrude upon each other,

and-a definite and clear line of demarcation exists between them without any shoulder or offset, the radius of curvature merely-changing at that line.

,- The machine shown in the drawings-comprises any suitable frame -or-stand, represented by the standards, 1, 1, and-top, 2. Upon the rear end standard, in suitable brackets, 3, there isjournaled-the horizontal A main shaft, 4, to which power is communicated in any convenient manner. On this mechanism mounted on the top of the table, hereinafter described, and a pulley, 7, by a belt, 8, drives the'vertical tool-holding or la operating shaft, 9, s'uitablyjoumaled on t e *11 is greater than the widthofthat $5 I on the crank wrist, 16, which hanger, 2 mounted de' ending from the top, 2. On this shaft is a orizontal pulley, 10,

- by which. it derives motion from the belt, 8. Upon the table top, 2, in a bearing bracket or 5 chair, 11', there is journaled a shaft, 12, having tight and loose pulleys, 13, 14, about which the belt, 6, passes from the pulley, 5, to rotate the shaft, 12. On the end of the shaft there is mounted a crank plate,v 15, and rojects from the face of the late there is rigid 17, which meshes with a twist gear, 1 8, said gear, 18, being mounted on the end of a shaft, 19, journaled in a bearing, 20, which 15 is mounted on a bar, 21 which is connected pitmanwise with the crank wrist, 16, back of the twist gear, 17, so that any means being provided for holding the shaft, 19, and bar, 21, substantially parallel and with their remote ends supported, the rotation of the shaft, 12, with its crank-plate and crankwrist, 16, will not only rotate the twist gear, 18, and its shaft, 19, butalso in each revolution will'operate the shaft, 19, and the bar,

25 21,that 1s, the shaft with its bearing,

with themovement of a pitman,that is, up and down the distance of the throw of the crank-wrist, and longitudinally with thrusting movement an equal distance; The

throw of the crank wrist is made variable by mounting it on the plate, 15, by means of the A bar, 16, pivoted to the plate at 15, and movablea out its plvot and secured as thus adjusted, by a bolt, 16?, in the slot, 15", ofv

the plate.- At the end ofthe bar, 21, and shaft, 19, remote from the shaft, 12 the bar carries a bearing, 22, in'which the shaft, 19, is journaled, so that the shaft and bar are he (1 arallel and move together in the pit- 40 manh e movement derived as described.

Back of the bearing, 22, the bar, 21, is guided in a vertical fork of a bracket, 23,

which is mounted upon the table, 2. Any.

convenient means, as the wei ht, 24, suspended from the bar, 21, may e-em loyed to 0 erate with a tendency to hold t e forware end of the shaft and bar downward with such ressure as may be afforded by the weight. he bar, 21, also supports-a bearii-o ing for a horizontal twist ear, 25; and the shaft, 19, has at the forwar end a twist gear, 26, for engaging the twist gear, 25; At the lower end of theshaft, 27, of the twist gear, 25, it is provided with a knob or ball termie nal, 28, which is adapted to seat in the back oru per side of a lens-holding block, 30, to the ower side or face ofwhich a lens blank, .31, may be cemented for hol it while it is beingdressech The block, 30, is rotated by the shaft, 27, and referably carrying a sleeve or anti-friction rofi, 35,- which bears against a stud or drive-pin, 36, which projects upwardly from the block, '30. It will be seen that the lens blank, 31, carried and driven a twist gear,

meansof a finger. or stud, 32, jutting off frombythe means described, will be free to oscillate in every direction about the ball, 28, and so as to accommodate itself in every respect to whatever is opposed to it for dressing it.

The shaft,9, is hollow and is journaled and hanger, 2, being rotated as already described. On the up er end of the shaft there is mounted remova ly, so as to permit substitution at will, the outer or annular lap, 39, having the center opening, 39*. Extending through this hollow shaft is a shaft, 40, which derives rotative movement from the hollow shaft by means of a cross pin, 40, in the shaft, 40, engagin a slot, 9", in the shaft, 9. A spring, 40', 00' ed around the shaft, 40, withinthe hollow shaft is stopped at the upper end by the cross pin and at the lower end is stopped on a bushing sleeve, 9 screwed into t e lower end'of the shaft, 9. The distance to which it is thus screwed in determines the tension of the spring and the -pressure,therefore,' with which the shaft, 40, is pressed upward or resists pressure 'downward. A flange on the lower end of the bushing sleeve has a finely graduated scale, 9,-which may be read with a graduated scale, 40, on a nut, 40, which is screwed onto the shaft, 40, and which is designed to be screwed'up or down thereon as the bushing sleeve is screwed up or'down on the shaft, 9, so as to keep the two scales in proximity for reading to indicate fineadjustment of the supplemental lap relatively to the annular lap, the two graduated scales bein constructed relatively in familiar manner or such-purpose; This adjustment is for such use adjusted to .sue tension that it practically upholds the central lap ositively, its u ward thrust being positive y limited also y the nut, 40 When em loying the 40*, will be relaxe considerably and the nut, 40, will be adjusted so that the central lap could protrude relatively to the-annular lap,

the nut, as before, but by its contact with the face ofthe'lens which is bein polished, and the tension of the spring .t ius determines accurately the pressure with which the annular lap acts for polishing;

At the upper end of the shaft, 40, it terminatesin a ball, 40*, upon which the inner lap, 44, is mounted, having its operating face upward.. This lap is driven by a stud, 40', which projects from the shaft, 40, below the knob, 40, and encounters a pin, 44, projecting downward from the la 44, and has, preferably, an antifriction s eeve, 40 as illustrated, with which directly the encounter. .of the pin, 44*,occurs. This lap, it

will be seen, hasthesame facility of accommodating itself to any surface pressing upon employed for grinding, the s ring, 40, being device for polishin the tension 0 the spring,

vertically stopped by its bearings in the a and it is thus adapted to be stoppe d,not by V es ers its operating face, as the lens blank, 31, mounted on the block, 30, has for accom modating itself to the pressure of the lap below it.

In the operation of this mechanism with the lensblan'k mounted as indicated, it will I r be seen that the lens itself receives a relatively slow rotation about its axis, and at the same time, an oscillatory or reciprocating movement. in a plane substantially at right angles to that-o the axis, the range of the oscillatory movement being the throw of the crank-wrist, 16. This throw is designed to' be substantially equal to the width of the annular interval between the two laps, 39

and 44, and by virtue of the rotary movement,which the lens blank receives about its axis,.this oscillatory or vibratory movement will cause the central lap, 44, to operate upon a circular area of'the lens whose radius is the radius of the lap plus half the width of said annular interval, or one-half the crankwrist stroke; andat the same time the outer annular lap, 39,'by reason of the slow rotation and reciprocating or oscillating, movement of the lens, will operateupon an annu lar area of the lens whose width is the width of the annular la plus half said annular interval,that is, ii In order that in grinding, the two laps shall operate soas to prevent any shoulder or et between the areas which they reeiped tivelydress, the adjustment mentlone by means of the micrometer scale is employed;

and in order that inapolishing, the slower travel of all points of the inner lap in their circular path due to its smaller diameter may be compensated by. greater pressure operating upon it, the inner lap is mounted so as to.

be ressed against the lank independently of t e annular lap, and the variation of that time swungv up free of the laps, so thatthe' operator cantest the advancement of the work of the two grinders, and'if it at any time appears that there is developing the slightest shoulder or offset between the surfaces dressed b them respectively, proper adjustment of t e inner lap can be made to \kee the two areas perfectly blending with eac other at the circle by which they are delimited from each other,that at which I the radius of curvature changes. It will be understood that the oscillation described is so short that it does not interfere in any respect with the curvature, especially in view of the fact that the lens blank, 31, accommodates itself always to the actual-curvature 0f the lap, 39, and would accommodate itself alf the crank-wrist stroke.

19, and the bearings even through a much larger range of oscillation, and that in like manner, the lap, 44, accommodates itself to the slight change of angle of the surface on which it is operating, so that the oscillation is Without effect upon the curvature.

I claim 1 In a machine forthe purpose indicated, two opposed elements, one for carrying the lens and the other carrying an annular lap and an auxiliary lap located within the opening thereofand annularly spaced therefrom; means for oscillating one of said two 0 posed elements and nieans for rotating one of them.

2. In a machine for the purpose indicated, two opposed elements, one for carrying the lens and the othercarrying an annular lap and an-auxiliary lap located within the opening thereof, and annularly spaced therefrom; means for oscillating one of said two opposed elements and means for rotating the lens carrier. 1 a

3. In a machine for the purpose indicated, two op osed elements, one for carrying the lens to e dressed and the other carrying an annular lap and, an auxiliary lap located within the opening thereof; means for rotating one of said elements; means common to the two laps for yieldingly pressing them both against the lens; -means for distrlbuting such pressure in predetermined ratio to the lenses, and means adjustable at will for varying such ratio.

4. In a machine for the purpose indicated,

two opposed elements, one for carrying the lens to be dressed; an annular lap and an auxiliary lap located within the opening thereof carried by the other element means yieldingly pressing the lens---carrier toward the'laps, and independent means for yield- .ingly pressing the auxiliary lap toward the lens.

5. In a machine for the purpose indicated, two opposed elements, one for carrying the lens to be dressed; an annular lap andan auxiliary lap located within the openlng thereof carried by the other element ;F means for rotating one of said elements; means for yieldingly pressin the lens-carrier toward the laps; indepen ent means for yieldingly pressing the auxiliary laps toward the lens,

and means for varying at will the pressure of said auxiliary element towardthe lens.

6. In a machine for the purpose lndicated,

two opposed elements, one for carrying the lens to be dressed and the other for carrying the 1a 3 for dressing it; means for osc llating one 0 said elements; means for rotating the lens-carrying element; an annular lap and a a central lap having their operating faces annularly spaced apart, the range of oscillation of the oscillatin element being substantially thewidth of sald annular space, and means for yieldingly pressing the two elements .for rotating one of said elements; means for a i '7 toward each. other adapted to' ermit the I faces annularly space central lap to be ressed towar the work independently of t e annular lap.

7. In a machine for the purpose indicated, two opposed elements, one for carrying the lens to be dressed and the other for carrying the la s for dressing it; means for oscillating one 0 said elements; means for rotating the lens-carrying element; an annular lap and a central lap having their grindin faces annularly spaced apart, the range of oscillation of the oscillating element being substantially the width of said annularspace; means for yieldinglypressing the two elements toward each other adapted to permit the central lap to be pressed toward the work independently of the annular lap, and means for varying at will such pressure of the central lap.

8. In a machine for the purpose indicated, two op osed elementsfone for carrying the lens to e dressed and the other for carrying the laps for dressing it; means for yieldin ly pressing said elements toward each other or holding the laps against; the work; means foroscillating one of said elements; means for rotating both the elements; anannular lap and a central lap having their operating apart, the range of oscillation of the oscillating element being substantially the width of said annular space.

9.. In a machine forthe purpose indicated, two opposed elements, one for carrying the lens to be dressed and the other for carrying the laps for dressing it; means for yieldin 1y pressing said elements toward each other for olding the laps in contact withthe work; means for osci lating and rotating the lenscarrying elements; an annular lap and a central lap, having their operating faces annularly spaced apart, the range of oscillation of the lens-carrier being substantially the width of said annular s ace.

10. Ina machine or the purpose indicated, two opposed elements, one for carrying the lensto be dressed and the other for carr ing the laps for dressing it; means for yiel mgly pressing the lens-carrying element toward the other element means for oscillating one of said elements means for rotating the lens-carrying element; an annular lap and a central lap having their operating faces annularlyspaced apart, the range of oscillation of the oscillating element being substantially the width of said annular space, and means for yieldingly ressing the central lap toward the work 1n ependently I of the annular lap.

11. In a machine for the purpose indicated, a lens-carrier and adap-carrier opposed to each other; means for oscillating and rotating the lens-carrier consisting'of a rotating crank;' apitman pivoted on the crank; a power-communicating wheel rigid with the crank; a wheel having bearing on the pitman meshed with the power-com- .steadying the pitman.

toward the lap.

municating wheel for deriving movement therefrom; a shaft'rotated by said second wheel hftving journal bearings on the itman and extending along the same to t e end thereof remote from the crank-wrist; a power-communicating wheel on said shaft at said remote end; a shaft mounted on the pitman at said remote end; a wheel on said shaft deriving movement from said lastmentioned wheel,the lens-carrier being carried by said shaft, and means for guiding and 12. In a machine for the purpose indicated, a lens-carrier and a lap-carrier opposed to each other; means for oscillating and rotating the lens-carrier consisting of a rotating crank; a pitman pivoted on the crank; a twist-gear having bearing on the pitman and meshed with the twist gear on the crank; .a shaft rigid withthe last-mentioned twist gear havm journal bearings on the pitman and eXten ing along the same to the end thereof remote from the crankwrist; a twist-gear on said shaft at said remote end; a second shaft mounted on the pitman at said remote end, and a second twist-gear thereon deriving movement from the lastmentioned twist-gear, the lens-carrier derivi-ing movement from said second shaft, and

means for guidin and stead 'ing the pitman 13. In a mac ine for tie purpose mdicated, a lens-carrier and a lap-carrier opposed to each other; means for oscillating and rotating the lens-carrier consisting of a rotating crank; a pitman on the crank; a power-communicatm wheel rigid with the crank; a second whee having bearing on the pitman'meshed with the power-communicatmg wheel for deriving movement therefrom;

' a shaft rotated by said second wheel having journal bearings on the pitman and extending along the same to the end thereof remote ing wheel. on said shaft at said remote end; a second shaft jo'urnaled on the pitman at said remote end, and a wheel thereon deri movement from said last-mentioned whee the lens-carrier being carried by said shaft;

means for guiding and steadying the pitman,

and means for yieldingly ho ding the pitman 14. In a machine for the purpose indicated, a lens carrier and a grinder-carrier opposed to each other; means for oscillating and rotating the lens-carrier consisting of a rotating crank; a pitman on the crank; a power-communicatin wheel rigid with the crank; a second whezi having bearing on the pitman meshed with the power-communicating wheel for deriving movement therefrom; a shaftrotated by said second wheel having journal bearings on the pitman and extending along thesame to the end thereof remote from the crank-wrist; a power-communicating wheel on said shaft at said remote end; a

from the crank-wrist; a power-communicatshaft jo'urnaled on the pitman at said remote end, and a wheel therefrom deriving movemovabl on the pitman for pressing its free end yie dingly toward the grinder.

15. In a machine for the purpose indicated, in combination with two opposed elements, one for carrying the lens to be dressed and the other for carrying the laps for dressing it, means for yieldingly pressing the lens-carrying element toward the other, the lap-carrying element comprisin a hollow shaft and an annular lap carried t iereby; a spindle extending through the hollow shaft and a central la carried thereby; means for rotating the ho low shaft and for communicating its rotation to the spindle, said means last mentioned being adapted to permit the longitudinal movement of the central shaft relatively to the other; a spring coiled about the spindle within the hollow shaft, and a bushing screwed into the hollow shaft for stopping and adjusting the spring.

16. In a machine for the purpose indicate'd, in combination with two opposed elements, one for carrying the lens to be dressed and the other for carrying the laps for dressing it; means for yieldin ly pressing the lens-carrying element toward the other, the lap-carrying element comprisin a hollow shaft and an annular lap carried tfiereb a spindle extending through the hollow s aft and a central lap carried thereby; means for rotating the hollow shaft and for communicating its rotation to the spindle, said means last mentioned being adapted to permit the longitudinal movement of the central shaft relatively to the other; a spring coiled about the spindle within the hollow shaft; a bushing screwed into the hollow shaft for stopping and adjusting the spring, and a nut screwed onto the end of the spindle which protrudes through the bushing, said bushing and nut having cooperating elements of a micrometer scale.

In testimony whereof, I have hereunto set my hand, in the presence of two witnesses, at

Chicago, Illinois, this 11th day of May, 1906.

GLILE O. ALLEN. In the presence of CHAs. S. BURTON, M. GERTRUDE ADY.

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