US2693058A - Lens grinding and the like machine - Google Patents

Description

Nov. 2, 1954 v G. HAGSTROM LENS GRINDING AND THE LIKE MACHINE 4 Sheets-Sheet 1 Filed Sept. 29, 1950 Nov. 2, 1954 a. HAGSTROM 2,693,053

LENS GRINDING AND THE LIKE MACHINE Filed Sept. 29. 1950 4 Shee ts-Sheet 2 r I. inventor:

Nov. 2, 1954 G. HAGSTROM LENS GRINDING AND THE LIKE MACHINE 4 Sheets-Sheet 3 Filed Spt' 29, 1950 ATTORNEY Nov. 2, 1954 G. HAGSTROM 2,693,058

I LENS GRINDING AND THE LIKE MACHINE Filed Sept. 29, 1950 4 Sheets-Sheet 4 beveled around the lens.

United States Patent O LENS GRINDING AND THE LIKE MACHINE Gotthard Hagstrom, Greenwich, Conn.

Application September 29,1950, Serial N 0. 187,595

25 Claims. (Cl. 51-101 This invention relates to certain improvements in optical lens grinding and the like machines; and the nature and objects of the invention will be readily apparent to and understood by those skilled in the art IrOrn the following explanation and detailed description of the accompanying drawings illustrating what I at present consider to be a .preferred embodiment or mechanical expression of a grinding machine of the invention for grinding optical lenses, from among various other embodiments, designs, adaptations, combinations and con structions and uses, of which the invention is capable within the broad spirit and scope thereof as defined by the appended claims.

Optical lenses after being surface ground to the required prescription, must thereafter usually be first edge ground to provide a flat peripheral edge surface therearound, if of the so-called -rimless type of lens, while, if

of the type to be mounted in a frame, the lens must after such edge grinding then have the ground edge thereof In accordance with the generally prevailing practices and techniques, such edge grinding and edge beveling are performed as two (2) separate and distinct operations on two (2) separate and distinct grinding machines. Thus, with the prevailing practices, it is necessary to mount and edge grind a lens in an edge grinding machine, then remove the lens and bevel by hand operation, or mount in bevel edging machine which reduces the lens to size and bevels in the limited grinding area of a V-notched grinding wheel.

One of the general objects of my present invention, with particular reference to adaptations of the invention -to machines for optical lens grinding, is to provide a single machine capable of etficiently precision grinding both the edge grind and the bevel grind around a lens without the necessity of removing the lens and resetting it, and

by mere simple adjustments of the machine to convert it for either edge grinding or bevel grinding.

Optical lenses vary according to' type and to the prescription to which they are shaped and surface ground. Such lenses frequently have their peripheral or surrounding edgeportion of wave or sinuous form around the major physical axis of the lens, that is to say, the peripheral edgeportion of the lens does not lie at all portions thereof and therearound in a plane perpendicular or normal to the axis about which the lens will be rotated in grindinga bevel thereon. Machines of the art for grinding a bevel on and around the ground edge of a lens have resorted to various mechanical-expedients for meeting the conditions presented by such peripheral edge shapes and forms of lenses, including providingfor relative movements axially between the lens'and the cir- -cular grinding wheel and controlling such relative movements positively bytemplates, patterns, cams, or the like -mechanical components and organizations. Usually edge beveling is carried out by a circular grinding wheel having a V-groove in and around its peripheral edge into which the peripheral edge portion of the lens engages, under the depth or radial movement control of a template for the particular lens being ground. 1 hemachines in general usefor lens edge beveling are of necessity of vrelatively complicated character, particularlyinthe template, pattern or other controls required to meet the foregoing conditions.

A further general object of my invention is to eliminate certain of the structural and mechanical complexities of the lens beveling, grinding machines of the art byprovidinga design, arrangement and mounting ofa ,circulargrinding .wheelby which the necessitywfor mechanism for positive control of the relative axial movements between the grinding wheel and the lens may be eliminated, while obtaining increased efliciency and precision for the bevelegrinding operation.

A further object is to provide a design and mounting of a circular grinding wheel having a peripheral bevel grinding groove therearoundby which the grinding wheel is ,caused to float in a balanced condition during rotation thereof yet which may be oscillated from and across its balanced position by relatively light pressures applied thereto in the proper directions, so that, the lens itself when in grinding contact in thebevel grinding groove of the grinding wheel functions as the pattern or template which effects the required positive directional moveand efficient mechanism for effecting such oscillation.

Another object is to provide such oscillating mechanism which will be capable of selecting adjustments by an iop'erator between active and inactive positions relative to the grinding wheel, without interfering with the floating mountingofthat wheel orits functioning when the oscillating mechanism is in inactive position.

A further object is to provide for positive oscillation of the grinding wheel for grinding surface dressing, through a greater predetermined degree of oscillation than that through which the grinding wheel is oscillated for edge grinding.

And a further object is to provide for'elfecting such dressing oscillation of the grinding wheel through the medium of the .same mechanism by which edge grinding oscillation is carried out; and further to provide for selective'setting'by-the operator of the oscillating mechanism for either-edge beveling or grinding surface dressing, respectively.

With the foregoinggeneral objectsand certain other objects, features and results in view which will be apparent from-the following detailed description, my inventron consists in certain novel features in design and construction, and in combinations and sub-combinations of parts and elements, all'as will be more specifically referred to and specified' hereinafter.

Referring to the accompanying drawings, in which similar reference characters refer tocorresponding parts and elements throughout the several figures thereof:

Fig -l is an exploded view showing certain of the essential components making up the grinding wheel and its mounting and the drives for the grinding wheel and for the lens and its-template, the part s being shown more or less schematically.inperspective'in the relativepositions thereofto be assumed in assembly.

Fig. 2 is a view inside elevationof the grinding wheel with a lens in grinding engagement therewith, taken from that side of the-wheel with whichthe wheel controlling .pms are associated, such pins being shown in transverse vertical section.

.Fig. 3 is a viewiin vertical section through the grinding wheel and its mounting, a lens being shown in edge elevation ingrindingengagement in the beveling groove of the wheel.

;Fig. 4 is aview .in :edge elevation of the grinding -wheel, showing itsmounting and controllingpins in side elevation.

Fig. 5 is a view-invertical longitudinal section through aform oflens grmdmgmachine of the invention, in-

cluding the componentsillustratedinFigs. l to 4.

Fig. .6 is a vertical transverse section through the machine. of Fig. 5, taken-as on the line 6-6 of'Fig. 5.

Fig. 7 is a'vertical transverse sectional view taken as on the lines 77 of Fig. 5.

A design and arrangementv of an optical grinding machine embodying theprinciples and features of mvinven- .tromand capableof .efiicientjfunctioning for. either lens edge grinding or lens edge beveling, is disclosed in the accompanying drawings by way of an example. It is to be understood that certain of the principles and features of the invention, as exemplified in the optical lens grinding machine illustrated and described herein, are not limited to solely machines for optical lens grinding, but are of general utility as adaptations to various types of surface or power grinding machines irrespective of the particular work or uses for which such machines may be intended or adapted.

Referring now to Fig. 1 of the drawings, there is shown therein more or less schematically the essential components and organizations making up the optical lens grinding machine of the example machine of Fig. 5. One of the basic components of the machine is the grinding wheel driving shaft 10 which is mounted in horizontally disposed position in suitable bearings in supporting structure carried on the machine frame structure 79. This shaft 10 is driven from a motor M, or other suitable source of driving power, through the medium of a pulley and belt drive comprised by the motor driving pulley 11 and driven pulley 12 mounted on one end of the grinding Wheel driving shaft 10, with a belt 14 in operative driving connection between the pulleys. Obviously any other suitable type of drive or power transmission may be utilized if desired. In the example machine it may be considered that the pulley 12 and the grinding wheel drive shaft 10 are driven from motor M through pulley 11 and belt 14, at a rate of 900 R. P. M., but such rate of rotation is given herein purely by way of example and not of limitation.

In accordance with the basic and one of the important features of my invention, a circular grinding wheel designated in its entirety as a unit by the reference character G, is mounted on driving shaft 10 for rotation by and about the axis of that shaft, but in such manner that the grinding wheel can be made to float for limited oscillation on and relative to the shaft 10 about an axis perpendicular to the axis of the driven shaft, by very light forces applied to the periphery of the wheel in directions acting axially relative to the wheel and its driving shaft.

Referring to Figs. and 6, the lens grinding machine in the instant example includes a generally rectangular, vertically disposed, box-like frame structure 70 Within which there is mounted and supported in elevated position a wall or base 71 disposed horizontally thereacross and therewithin and providing the upwardly extending pedestal or column structure '72, in and across which the grinding wheel driving shaft is mounted and journaled in the spaced bearings 10a. Pulley 12 is mounted on one end of shaft 10 at the outer side of column structure 72, while the shaft 10 at its opposite or inner end projects a distance inwardly across the column structure 72 in position to mount on its inner end for rotation therewith the grinding wheel unit G- In carrying out and expressing mechanically in the example machine, that feature of my invention by which the grinding wheel G is made to float in a laterally balanced condition, I have mounted on the inner end of the wheel driving shaft 10, a ball or generally spherically formed member 20. The grinding wheel G is mounted on ball member 20 in direct driven connection therewith for rotation about the aligned axes of the shaft and wheel with the wheel being held against rotation on and relative to the ball member 20 and shaft 10. However, provision is made for rocking or oscillation bodily of the wheel G about an axis intersecting but perpendicular to the axis of rotation, so that the wheel may thus be rocked on and independently of the ball member 20 and its shaft 10 in directions axially of the shaft.

in this instance, the grinding wheel unit G includes a hub 39 having a main wheel body or flange in the form of a circular plate 31 extending radially therefrom and therearound. The wheel body or plate 31 terminates on and around its peripheral edge in a circular shouldered seat 32 on and around which the annular grinding stone component 33 of the wheel is mounted in suitably attached and locked position thereon. Grinding wheel hub 30 is formed with an axial bore therethrough which is partially closed at one end of the hub by an annular, frustro-conical end wall 34. End wall 34 is precision ground or otherwise formed around its inner surface within the hub bore to provide a complementary, curved spherical surface 34a which forms a sliding fit with and around the outer end portion or side of ball member 20, as will be clear by reference to Figs. 3 and 5. A suitable retaining and bearing ring 35 is threaded into the inner, wide diameter end of the hub bore around and receiving therethrough the shaft It). The inner side of this retaining and bearing ring 35 is formed curved to provide a complementary surface 35a for receiving and fitting against the inner side of ball member 20 with a sliding fit. Thus, in the absence of restraint other than the internal width of the driving shaft receiving bore 35b of ring member 35, the grinding wheel G would have universal mounting on and be rotatable and rockable gnivesally about a center provided by the ball mem- However, in accordance with my invention a positive driving connection is provided between ball member 20 and the hub .30 of grinding wheel unit G, which fixes the ball member and the grinding wheel against rotation relative to each other about the axis of shaft 10, while permitting limited rocking or oscillation of the grinding wheel unit on the ball in directions axially of the shaft and laterally relative to the wheel. In the present example, such driving connection takes the form of a pin 36 extending radially inwardly from the hub 30 of wheel 6 into the bore thereof, with'this pin slidably received in a circumferentially disposed slot or groove 21 (see Fig. l) which is disposed axially of shaft 10 with the longitudinal center thereof lying in a plane passing through the axis of the shaft and the center of ball member 29. Thus mounted and connected, the grinding wheel G is placed in positive driven connection with the spindle it) for rotation therewith as a unit about the axis of the spindle and the center of ball member 20 with the grinding wheel G free to be rocked or oscillated through a limited range in a direction axially of spindle 10 and about the center of ball member 20. Hence, the grinding wheel G while being maintained in positive driven connection with the shaft 10 by the pin and groove connection 36-21, may be rocked or oscillated laterally in directions axially of the shaft. During such oscillatory movements driving pin 36, which has an outside diameter to form a running fit in groove 21, may rock in and through the groove of the ball member without play laterally or radially of the pin in the groove.

Upon rotation of grinding wheel G by the shaft 10, if the wheel is laterally unconstrained, the wheel will, due to the action of centrifugal forces and the resulting gyroscopic effect, assume and maintain its normal position of rotation in a plane perpendicular to the axis of shaft 10 and wheel rotation. I have discovered, and I have devised the example embodiment as an operative mechanical expression of such discovery, that if the grinding wheel G is displaced or rocked laterally on the ball member 2t about the center of the ball to a position deflected from its normal position of rotation in a plane perpendicular to the axis of the shaft 10, and is then held or maintained in such deflected position by forces which balance the forces acting to restore the wheel to its normal position, there will result in effect a balanced condition of the wheel in which the wheel floats about the center of the ball member. In such a deflected position of balance or floating which is attained during rotation of the grinding wheel G, the wheel may be caused to oscillate about the center of the ball member 20 by very light, laterally acting deflective forces applied to the wheel in either direction axially of shaft 1d. The angularly displaced or deflected floating position of grinding wheel G may be taken to be in the example hereof, as of the order of three degrees (3") of deflection. Such position of angular displacement or deflection of grinding wheel G about ball member 20, is illustrated in Fig. 4.

Referring now to Figs. 5 and 6, the angular displacement or deflection of grinding wheel G may be effected by'a pair of deflecting pins 40 and 41 which are mounted in horizontally disposed position extending through and for reciprocation in a vertically disposed supporting bracket structure 73 mounted on the base 71 within frame 76 at and spaced from the outer side of the grinding wheel G. The pins 40 and 41 are mounted in bracket structure 73 in positions engaging at their inner ends the adjacent side of the plate or body 31 of the grinding wheel G. As will be clear by reference to Figs. 2 and 6, these pins 40 and 41 are so positioned as garnets to engage the wheel body 31 at diametrically opposite locations thereon, with pin 40 located below and pin &1 located an equal distance above a horizontal plane passing through the axis of rotation of wheel G. In order that the side of wheel body 31 may have minimum friction, rotative engagement with the inner ends of the deflecting pins '40 and '41, I have provided an annular, thrust type of bearing assembly 42 on wheel body 31 around hub 30, with the outer annular ring or race plate '43 of this unit engaged by the inner ends of pins 40 and 41. Thus, the grinding wheel G may be rotated while engaged by pins '40 and 41 for wheel defiection, with a minimum of friction, even with the pins exerting the forces necessary to laterally displace or deflectthe grinding wheel to the desired angular position. The grinding wheel deflecting pins 40 and 41 are mounted and adjusted in the bracket structure 73 so as to angularly displace and hold the grinding wheel continuously in its displaced position against the forces generated by rotation of the grinding wheel which act to restore the wheel to its normal position of rotation about the center of ball member 20. These pins can be fixed or set in the necessary positions and, if desired or found expedient, thepins may be provided with suitable shock and vibration absorbing springs 40a and 41a. These springs may be of the compression type requiring forces to compress them of a greater magnitude than the forces normally acting to restore grinding wheel G from the angularly deflected position to its normal position of rotation.

, The annular grinding component or ring 33 (see Fig. 1) of grinding wheel G may be formed of any suitable one of the well known grinding wheel materials for lens grinding, such as a diamond impregnated material. The outer periphery of grinding component 33 is formed circular and truly concentric with the ball member of the wheel mounting, and is curved transversely to provide the transversely convex peripheral edge grinding surface 33a therearound for performing lens edge grinding operations. In addition the grinding component 33 is provided with a groove 33b in and around the perip'eral grinding surface 3311, with this groove being truly concentric with the ball member 20. Groove 33b "is provided for performing the lens edge beveling operations, and in this example, is located on and around grinding component 33 with the groove being of V-sh'ape 'in, cross section and having its apex lying in theplane of the plate-like body 31 of the wheel, as will be clear by reference to Fig. 3 in particular.

A lens L to be either edge ground or bevel ground, is mountedand positioned in a suitable work holding and rotating mechanism, with the lens held thereby in position'generally parallel with the grinding wheel G to engage the edge of the lens in operative grinding relation with 'either the grinding surface 33 1 or the edge beveling groove 33b of the grinding wheel. Referring to Fig. 5 in particular, a lens L to be ground is releasably clamped and secured in operative position between the rotati've clamping "jaws or members '51 and '52 of the work holding mechanism, in a manner generally familiar in this art. The work holding mechanism which includes'the clamping jaw members 51 and 52, is mounted on a head or cover structure 80 which is 'pi'votally mounted or hinged in position on and across the upper end of the machine frame structure 70 for swinging forwardly'and downwardly to operative grinding position with the lens L in grinding engagement with grinding wheel G, and for swinging upwardly and "rearwardly from operative position to a vertically dis posed, inactive position with a lens completely removed from grinding wheel G, as clearly shown in Figs. 5 and 6. i Clamping jaws 51 and 52 are mounted in heador cover "80 in axial alignment and positioned disposed with their axes generally parallel with the axis of rotation of grinding wheel driving shaft 10. The clamping jaws 51 and .52 are generally centrally located in the cover structure "80 in a well or recess formed by a reen'trant portion 80a of the cover structure. In this example, clamping ja'wSjl is mounted on the inner end of a driven, rotary shaft 53 which is journaled in suitable bearings '53a provided by the cover structure. One of the bearmgs 5321 is provided in a sidewall of cover structure '80 v'vith"shaiitSS extended outwardly beyond such side wall and mounting'at the outerend thereof the usual templet "6 T. The jaw 51 and temple't T are rotated by and with shaft 53, with the ternplet T providing by its peripheral edge contour a precise replica or pattern'of the finished, ground contour which it is desired 'to grind on the lens L. A suitable anvil (not shown) is positioned for engagement by the peripheral edge of templet T "in the general manner familiar to those skilled "in this art. In operative position of "cover structure with the periphery of the lens L in engagement with grinding wheel G, the templet T rotatably engages a suitable fixed surface, such as the usual anvil "(not shown), so that, what is in effect a depth control, or control of radial movements inwardly and outwardly, of a lens L in grinding engagement with wheel G is obtained.

The clamping jaw 52 is mounted 'on a suitable idler shaft 52a whichis journaled in a side wall of the reentrant .portion 80a of cover structure "80, and which mounts a biasing Spring 5211 by which elarnping 'jaw sz is spring loaded to eifect clamping "of a lens blank be;- tween it and clamping jaw 51. 'An externally threaded rod 520 is threaded into a bushing in aside wallof cover structure 80 and 'mounts it at its outer end a handszwheel 52d, for effecting adjustment of clamping J r.

Shaft 53 is driven from a "shaft 54 journaled "at the under side of cover 80 inposition with its axis perpe'n dicular to the axis of shaft 53, through a set of bevel gears 55. A countershaft 56 is mounted in horizontally disposed position on and extending across the upper end of frame structure 70, and it is this shaft 56 that forms the hinge axis on and about which the cover structure 80 with the lens blankclampin'g jaws 51- 52, 'isrn'o'unted for swinging to and from operative positions as referred to hereinabove Shaft '56 is journaled 'in and extending between abearing boss or block 73a "horizontally disposed at the upper end of bracket structure 73, and bearings provided in the opposite side vertical walls of a gear case 7201 mounted on and extending vertically upwardly from the upper end 'of pedestal or support structure 72. A bushing or sleeve 56a extends outwardly from the outer side of the gear case 7221 and forms a trunnion or hinge pin on which the adjacent side wall of cover structure 80 is rotatably mounted by means of an inwardly projecting "sleeve 56b. The cover structure 80 is rotatably mounted on the opposite end of shaft 56 by a bearing 560 in the vertical side wall of the cover structure, so that the cover structure thus has hinge support at one side on shaft 56 and-at the opposite side on the bea'ringsleeve5'6a. In order to provide for adjustment laterally of cover structure 80 to adjust a lens L mounted in clamping jaws 51 and 52 to position with the lens engaged in beveling groove 33b or engaged with the edge grinding surface 3321 of grinding Wheel G, the sleeve 56:: is H internally threaded and receives therein the externally threaded inner end of an adjusting shaft 56d which is journal'ed in the adjacent side Wall of cover structure 80 and which mountsat its outer end an adjusting hand wheel 562,

The shaft 54 which drives s'haft'53ofthe rotary wo'rk h ldin me hanism, is driven from c'ountersha'ft "56 through a set of bevel gears 57. Thus as cover 80 is swung from and to operative position, that bevel gear 57 on shaft 54 will ride around the bevel gear 57 o'n shaft 56, so that driving connection ismaintained at'al'l timesbetween counter-sha'ft'56 and the shaft '53 of the wor holdingmechanism.

The countershaft 56 is driven from the "motordrive'n, grinding wheel driving shaft 10, through a "speed reduc- 'tion gear train R which includes, in this exam le a spur gear mounted on a shaft91which is joinnaled'in and extending across-the lower side'of gear case 7221 in p'o's'ition with its axis parallel with the axis 'ofdrivir'fgshaft 10. "A Wormwheel 9-2 is mounted 'onsh'aft 91 and is in driven engagementwith a worm '93e1ra-suart: 94w hifch is journaled in and extending aerosscol'umn structure 72 intermediate shaft 10' and shaft-91 withits axis perpendie ular to the axes of the latter shafts. A worm wheel 95 is fixed on shaft '94 in positionabovedriving shaft 10. A worm96 fixedon shaft 10-is"in driving meshfwith the worm 95 at the underside thereof. Thus, shaft lfidrives gear 90 through worm '96, worm wheel 95, shaft 94, Worm 9.3 "and worm wheel "92. Theeountersh t- "*6 mounts thereona spur gear 97 inmesh-with gear9 *on shaft-91, so thatgear 97 is thereby driven to rotate the eeuntershan sa. Retatien bf shaft efi will thrwgh eliatt 54, bevel gears 57 and bevel gears 55, effect rotation of shaft 53 to thereby revolve a lens L mounted in clamping jaws 51 and 52. The gear ratios through the above identified'train of gears and shafting is such that a lens L mounted in the clamping jaws 51 and 52 will be revolved at a rate of one (1) R. P. M.

The location and positioning of the grinding wheel deflecting pins 40 and 41 relative to the grinding wheel G and to a lens L mounted in position clamped between jaws 51 and 52, and the relative position of the lens L to the vertical plane passing through the axis of the wheel G, are shown by Fig. 2 in particular. It will be noted that a line a-b drawn intersecting the axes of the diametrically opposite pins 40 and 41 and passing through the center of the ball member 20 is perpendicular to a line c-d drawn through the axis of lens blank L and the center of ball member 20. If unrestrained by the pins 49 and 41, the grinding wheel G would when rotated by shaft 10 at a sufficient rate of speed be subjected to centrifugal forces developing a gyroscopic action which would cause wheel G to assume and maintain a position in a plane of rotation perpendicular the axis of shaft 10 about the true center of the ball member 20. I have established that when displaced laterally to an angle and by forces of a magnitude to balance the wheel restoring forces, that then the grinding wheel assumes when rotated a position of balance in which the wheel, in effect, freely floats, so that it may be oscillated in directions axially of shaft 10 by relatively light, laterally acting forces applied thereto. When so oscillated or deflected while maintained in its floating condition of balance the grinding wheel may be oscillated about the inner ends of pins 40 and 41 as fulcrum points and about an axis of oscillation as defined by the line a-b shown in Figs. 2 and 6.

Thus, with a lens L in operative grinding position clamped between jaws 51 and 52, and with the head structure 80 lowered to position with lens L having its peripheral edge portion in grinding engagement with the groove 33b of grinding wheel G under the positive control of the templet T, the wheel G freely floating in its angularly displaced position of balance will rock or oscil late freely about axis [1-12 to precisely follow the peripheral edge shape or contour laterally of the lens L as the lens is rotated by the clamping jaws 51 and 52. The lens L thus itself functions as a templet or pattern for effecting and controlling precisely the oscillations of the freely floating grinding wheel G to cause that wheel to follow the contour laterally of the peripheral edge portion of the lens blank so as to thereby effectively and efficiently bevel grind the lens.

A machine of my invention for lens edge beveling and embodying the components and the organization and association thereof as hereinbefore described and explained, is also adapted for operation of the grinding wheel G for edge grinding of a lens as distinguished from bevel grinding thereof. The grinding component 33 of the grinding wheel G provides by its peripheral grinding surface 33a which is located between the outer edge thereof and the beveling groove 33b therein, a surface for grinding engagement with a lens to edge grind the same. Such edge grinding operations are effected without adjustment in or interference with the wheel deflecting pins 40 and 41, or the free floating and oscillation of grinding wheel G about the axis ab provided by those pins. In fact, edge grinding operations are performed by positive oscillation through a predetermined range of the grinding wheel G about the fulcrum provided by the inner ends of pins 46 and 41 and the axis ab, in the same manner as the oscillations effected by thelens during floating of wheel G, but through a greater angular range of oscillation.

Referring now to Figs. 1, 2, 5 and 6, I provide a pair of grinding wheel oscillating rods 60 and 61 which are slidably mounted in horizontally disposed position for reciprocation in and through the bracket structure 73, for engaging at their inner ends the outer raceplate 43 of the annular thrust bearing unit 42 mounted on the grinding wheel body 31. The inner ends of rods 60 and 61 engage wheel body 31 at points diametrically opposite and equally spaced from the center of ball member 20, at locations 90 around the wheel G from the deflecting pins 40 and 41, and in positions with their axes intersected by and perpendicular to a line cd drawn through the axis of rotation of a lens L at the -8 center of ball member 20, as will be clear by reference to Figs. 2 and 6.

In the example machine, the rods 60 and 61 are arranged for simultaneous axial movements for reciprocation in opposite directions alternately to thereby oscillate grinding wheel G back and forth about the axis a-b provided by grinding wheel deflecting pins 40 and 41. The rod 60, in this example, is displaced inwardly positively under the control of a power driven cam 62 mounted on a shaft 63. The rod 61 is spring loaded by spring unit 610 and functions as a follower or return rod for effecting oscillation of grinding wheel G in the reverse direction to that imparted to the wheel on the power stroke of rod 60. Thus, upon completion of the power stroke of rod 61 by cam 62, spring loaded rod 61 acting on the opposite side of the axis of oscillation, reverses the direction of oscillation and effects the displacement or deflection of the grinding wheel G in the opposite direction. During this return stroke of rod 61, the low side of cam 62 is opposite the outer end of rod 60 and the rod is caused to follow around such low side. Upon completion of the restoring and reversing stroke of rod 61, the high side of cam 62 will be rotating into engagement with rod 60 so as to then follow with the power stroke of rod 60.

The cam 62 is fixed on a shaft 63 which shaft is journaled at its opposite ends in the opposite side walls 64 of a swinging frame 65. This frame 65 is pivotally mounted at its upper end along a hinge line spaced above reciprocating rod 66, so as to position shaft 63 in horizontally disposed position extending across the outer end of rod 60 with the axis of the shaft 63 perpendicular to the axis of the rod. The pivotal or swinging mounting of frame 65 is effected by pivotally mounting the upper end of the side walls 64 of the frame on a shaft 66 which is mounted and journaled within frame 70 spaced above rod 60 and parallel with shaft 63. The shaft 66 at its rear end mounts a bevel gear 66a thereon which is in driven mesh with a bevel gear 66b fixed on the end of the shaft 91, which shaft is extended from supporting structure 72 across and spaced rearwardly from grinding wheel G to position bevel gear 66b for meshing engagement with gear 66a on shaft 66. Thus, shaft 66 is continuously driven during operation of the machine from shaft 91 which in turn is driven from the driving shaft 10 of the grinding wheel. The swinging frame 65 being rockably hung and depending from shaft 66 can thus be rocked between inwardly swung position with cam 62 engaged with rod 60 and outwardly swung position with the cam in inactive. position disengaged from rod 60. The shaft 63 is driven from shaft 66 through the medium of a wide gear 67 fixed on shaft 63 and in constant mesh with a narrow gear 68 fixed on shaft 66. As swinging frame 65 is hung from and rocks on shaft 66 as an axis, it follows that notwithstanding the positions to which frame 65 may be swung, the gears 67 and 68 remain in constant mesh.

in this example, the swinging frame 65 is constantly biased by a spring unit 65s to its inactive position swung outwardly to disengage cam 62 from rod 64). In order to swing frame 65 inwardly to operative position with cam 62 engaged with the end of rod 60, an operator control is provided which comprises a horizontally disposed shaft 65a mounted in frame 70 below frame 65, with this shaft extending forwardly to the exterior of the machine where an operating hand lever 65b is mounted on the shaft end. A depending arm 650 is provided at the outer or underside of frame 65 and a cam 65d is mounted on shaft 65a with its camming periphery engaged against depending arm 65c. Cam 65d presents a high side and a low side and when rotated by shaft 65a to engage the high side with arm 65c, the swinging frame 65 is rocked inwardly against the forces of spring unit 65s, to operative position of the frame with cam 62 engaged with rod 60.

The cam 62 is designed to have a throw to oscillate the grinding wheel G through a predetermined range of oscillation for moving grinding surface 33a back and forth across the edge of a lens L to effect edge grinding of the lens. However, my invention provides a further feature by which the grinding wheel G may be oscillated through a greater predetermined range for dressing the grinding surface of the grinding wheel. In carrying out this feature in the example embodiment, I mount a cam 69 on shaft 63 of swinging frame 65 in position between wages cam 62 and the gear 67 on shaft 63. The swinging frame 65 is thus so hung and mounted on shaft 66 that the frame with its Contained shaft'63 gear 67 and cams 62 and 69, can be moved through a limited range axially of shaft 66 in either direction. Thus, in the illustrated example, when the swinging frame 65 is at its limit of movement rearwardly on shaft 66 as shown in Fig. 6, the edge grinding, oscillating cam 62 is in line with rod 60. By bodily moving swinging frame 65 forwardly on shaft 66 to itslimit of forward movement, the cam 69 is then placed in position for operative engagement with rod 60, while cam 62 is removed to inactive position. During such movements and in such positions of adjustment, the gears 67 and 68 remain in mesh, as the narrower gear 68 merely slides axially across the wide gear 67.

I provide operator controlled means for selectively setting the swinging frame 65 to a position with cam 62 lined up with rod 60 or to' a position with the cam 69 lined up withthe rod. Such control may take the form ofthe'present example, in which a rod 69a is fixed at its inner end to the forward side wall 64 of swinging frame 65, and extends forwardly therefrom through the forward or front wall of column structure 76. A suitable operating knob 69b is fixed on the outer end of rod 69d at the exterior of column structure 70 for ready access by the operator. To selectively adjust and set the cams 62 and 69 of swinging frame 65, the operator merely pushes or pulls rod 6%, whichever action required to place the desired cam in operative relation with push rod 60.

With the example machine, a lens L clamped between jaws 51 and 52, may be adjusted in an axial direction relative to grinding wheel G by adjust ng the cover structure 80 transverse of the machine through the medium of the hand wheel 566. By such adjustments a lens L can be displaced axially relative to the bevel grinding groove 33b, in order to compensate for the various curves encountered with lenses of diiferent prescriptions. Thus, a lens which has a deep curve or one which is nearly flat can be adjusted to a proper position relative to beveling groove 33b, so as to fit in the center of the beveling groove and thereby eliminate the uneven lateral pressures that may be caused should the lens be off to one 'side relative to the bevel grinding groove.

In order to perform an edge grinding operation on a lens' L clamped between jaws 51 and 52 of the work holding mechanism, the operator raises cover structure 80 to its inactive position indicated in Figs. 5 and 6 by dotted lines, and then actuates the hand lever 65b to rock frame 65 inwardly to place cam 62 in operative association with the grinding wheel oscillating rod 60. The operator then adjusts the cover structure 80, if adjustment is required, and lowers the cover structure until the lens L is engaged against the grinding wheel G in grinding contact therewith under the depth or radial movement control of template T. It is understood, of course, that cams 62 and 69 will have been set by the operator through manual operation of knob 69b, to line cam 62 with rod'60. Thereupon, with the machine in operation driven by the motor M, there will result the edge grinding oscillation of wheel G about the fulcrum line ab, so that the grinding surface 33aof the wheel is rocked back and forth across and in edge grinding engagement with the peripheral edge of the lens L as the latter is rotated from shaft 53 in the manner hereinbefore described. The lens L, in the instant example, is rotated at one (1 R. P. M., with the grinding wh'eel G being rotated at nine hundred (900) R. P. M., while the rods 60 and 61 operate to oscillate wheel G to move the grinding surface 33a thereof at the required rate hack and forth across the peripheral edge of the lens L for the purposes familiar in this artfor lens edge grinding.

When it is desired to convert the machine from edge grinding to lens edge beveling, it is merely necessary for the operator to raise cover structure 80 to inactive position and then actuate hand lever 65b in adirectio'n to release the swinging frame 65 to the control of spring unit 65s, so that frame 65 is swung outwardly to its inactive'position with cams 62 and 69 removed from engagernent with rod 66. In such inactive position of frame 65, the machine may be continued to be operated from motor M and the cams 62 and 6? will continue to be rotated even in the inactive position of the frame due to mend that bevel gears 66a and 66b remain in operative mesh. Thus, when frame 65 with its cams 62 and 69, is in inactivepos'ition the grinding wheel G'is released to its free floating, balanced position of angular deflection for oscillation'about the fulcrum line a-b under the "controlofa lens L engaged in' the beveling groove 33b. 2

After rendering the oscillating cams 62 and 69 inactive, the operator may, after first making any necessary adjustment in the position of lens L by means of hand wheel 56a, lower cover structure 86 to position lens L with its peripheral edge in bevel grinding engagernent in the beveling groove 33b of the grinding wheel G, the lens L being of course under the'control of the template T in the usual manner. Thereafter, as the lens L is revolved in grinding engagement in bevel: ing groove 33b, as grinding wheel G is rotated, the peripheral contour laterally of lens L will effect oscillations laterally in either direction, of the free floating, balanced grinding wheel G, 'so that the exact contour of the lens peripheral portion is precisely followed by wheel G and a precision ground bevel is formed on and around the lens L.

If it should be desired to dress the grinding surface 33a of grinding wheel G, the cover structure is swung upwardly to its inoperative position, as shown in dotted lines Fig. 6. The operator then draws rod 69a outwardly by finger knob 69b, to position the Wider throw cam 69 in operative alignment with the oscillating rod 60. After thus setting cam 69,, the operator may then by hand lever 65b rock swinging frame 65 inwardly to position the cam 69 in operative engagement with the OSCillating rod 60. With the machine so adjustedthe grinding wheel G is oscillated through a greater degree of oscillation than that utilized for edge grinding, so that a dressing tool may be suitably mounted for dressing engagement with grinding surface 33a for dressing that surface as the grinding wheel is oscillated under the control of cam 69, rod 60 and the spring loaded return rod 61.

It is also evident that various changes, modifications, substitutions, elirninations and additions may be resorted to without departing. from the broad spirit and scope of my invention, and hence I do not desire or intend to limit the invention in all respects to the exact and specific expressions thereof exemplified by the illustrated example machine, except as may be required by specific and intended limitations thereto appearing in any of the appended claims.

What I claim is:

1. In a grinding machine, in combination, a driven shaft; a grinding wheel mounted on said shaft in positive dr ven connection with the shaft for rotation about the axis of the shaft; said grinding wheel being also mounted for free and limited oscillation laterally about an axis perpendicular to the axis of said shaft; and deflecting members engaged against said Wheel at one side thereof at locations diametrically opposite the axis of rotation of the wheel adapted to force said wheel to and main: tam it in a predetermined deflected position angularly disposed relative to a plane perpendicular to the axis of th shafl- 2. In a grinding machine, in combination, a driven shaft, a grinding wheel mounted on said shaft in positive, drlven connection therewith for rotation by the shaft around the shaft axis as a center; said grinding wheel being also mounted on said shaft for free and limited oscillation laterally in either direction about an axis perpend cular to the axis of said shaft during rotation of said r i eel in mcm a en a one i of sa1d wheel adapted to continuously exert deflecting pressures on said wheel to deflect and maintain said wheel in position on said shaft at an angle toa plane perpendicular to the shaft axis of rotation; and said deflecting members prov ding a fulcrum about which said grinding wheel is adapted to be oscillated.

3. In a grinding machine, in combination, a driven shaft; a grinding wheel; means mounting" said grinding wheel on said shaft in positive'driven connection therewith for rotation of said wheel about the shaftaxis as a center; sa d wheel mounting meansbeing also constructed and arranged for free 'and'limitedoscillation laterally of sa d wheel on said'shaft abohtan axis perpendicular to the axis of the shaft' during rotation of the wheel by the shaft; means fer ,deflecting said 'wheef'late rally 9 nd emaining t e heeiififdeffi jw i si ianan posed at an angle to a plane perpendicular to the axis of said shaft during rotation of the wheel by the shaft, and means adapted to be operatively engaged with said wheel for positively oscillating said wheel.

4. In the combination as defined in claim 3, manually controllable means for selective operation to engage said oscillating means with or disengage said oscillating means from said grinding wheel.

5. In a grinding machine in combination, a driven shaft; a grinding wheel mounted on said shaft in positive driven connection therewith for rotation by the shaft around the shaft axis; said grinding wheel being also mounted on said shaft for free and limited oscillation laterally about an axis perpendicular to the axis of said shaft during rotation of said grinding wheel; a fixed support structure at one side of said grinding wheel; and spring loaded pin members slidably mounted in said support structure in positions continuously engaged at diametrically opposite locations against one side of said grinding wheel to continuously exert forces acting on said wheel to maintain said wheel deflected laterally to a position at an angle to a plane perpendicular to the axis of said shaft at which the centrifugal forces generated by rotation of said wheel tending to restore the wheel to a position in a plane perpendicular to the shaft axis are balanced by the deflecting forces applied to the wheel by said spring loaded pin members.

6. In the combination as defined in claim 5, antifriction bearing means interposed between said wheel and the wheel engaging ends of said pin members for rotative engagement of said wheel with the adjacent ends of said pin members.

7. In a grinding machine, in combination, a rotary, driven shaft; a grinding wheel mounted on said shaft in positive driven connection therewith for rotation about the axis of the shaft; said grinding wheel being also mounted for free, limited oscillation laterally about an axis perpendicular to the axis of said shaft; wheel deflecting members engaged at their inner ends against the adjacent side of said wheel and being adapted to continuously exert forces on the wheel acting in a direction to deflect the wheel laterally to a position at which the forces acting on said wheel are balanced with the wheel floating for free oscillation; said wheel deflecting members constituting fulcrum members about which said wheel may be freely oscillated; wheel oscillating members engaged with said wheel at diametrically opposite points thereon spaced angularly therearound from said wheel deflecting members; and means adapted to be engaged with said wheel oscillating members for effecting positive oscillation of said wheel.

8. In combination; a circular grinding wheel providing a peripheral grinding surface therearound; said grinding surface being formed with a beveling groove therein and therearound concentric with the axis of rotation of said wheel; said wheel being mounted for oscillation laterally about an axis perpendicular to the axis of said wheel; means for rotating said wheel; means for forcing and maintaining said wheel deflected laterally to a position at which the forces acting to restore said wheel to position in a plane perpendicular to the axis of rotation are balanced by the deflecting forces to cause the wheel to float in a condition of balance for free lateral oscillation; and means for mounting a circular work piece in position with its peripheral edge portion received in grinding engagement in said beveling groove of the grinding surface of said wheel.

9. In combination, a circular grinding wheel providing a peripheral grinding surface therearound; said grinding surface being formed with a beveling groove therein and therearound concentric with the axis of rotation of said wheel; said wheel being mounted for free oscillation thereof laterally about an axis perpendicular to the axis of rotation of the wheel; means for rotating said wheel; and means for forcing and maintaining said wheel deflected laterally to a position at which the forces acting to restore said wheel to position in a plane perpendicular to the axis of rotation are balanced by the deflecting forces to cause the wheel to float in a condition of balance for free oscillation by the application thereto of relatively light, laterally acting forces.

10. In combination, a circular grinding wheel providing a peripheral grinding surface therearound; means for rotating said wheel; said grinding surface'being formed with a beveling groove therein and therearound concentrio with the wheel axis of rotation; said grinding wheel being mounted for free oscillation thereof about an axis perpendicular to the axis of rotation of the wheel; rotatable work holding means adapted to mount therein a circular work piece for rotation thereby about an axis generally parallel with the axis of rotation of said grinding wheel; said work holding means being mounted for movement to and from an operative position with the peripheral edge of a work piece mounted therein held in bevel grinding engagement in said beveling groove of the grinding wheel; deflecting means mounted independently of said work holding means for forcing and maintaining said grinding wheel deflected laterally to a position at which the forces acting thereon to restore said wheel to a position in a plane perpendicular to the axis of rotation are balanced by the deflecting forces to cause the wheel to float in a condition of balance for free lateral oscillation under the action of forces applied thereto laterally by the contour of the peripheral edge portion of a work piece when in grinding position in said beveling groove.

11. In a grinding machine, in combination, a driving shaft; a grinding wheel mounted on said shaft in driven connection therewith; said wheel being also mounted on said shaft for oscillation laterally relative to said shaft on and about an axis perpendicular to the axis of said shaft; a work holder for supporting a work piece in grinding engagement with said grinding wheel; and means independent of said work holder for forcing and maintaining said wheel deflected laterally to a position at an angle to a plane perpendicular to the axis of said shaft at which the centrifugal forces generated by rotation of said wheel are balanced by the opposing deflecting forces exerted by said means.

12. In a grinding machine, in combination; a driven shaft; a spherical member fixed on said shaft concentric therewith for rotation with the shaft; a grinding wheel mounted on said spherical member for oscillation laterally on and about an axis perpendicular to said shaft; means providing a positive driven connection between said spherical member and said wheel for efiecting rotation of said wheel with said spherical member and shaft about the axis of said shaft as a center; a work holder for supporting a work piece in grinding engagement with said grinding wheel; and means independent of said work holder and of a work piece mounted therein for positively oscillating said wheel on and reltaive to said spherical member and shaft through a predetermined range of oscillation.

13. In a grinding machine, in combination, a driven shaft; a spherical member mounted on said shaft in fixed driven connection therewith; a grinding wheel mounted on said spherical member for oscillation laterally thereon about an axis perpendicular to the axis of said shaft; means connecting said grinding wheel in positive driven connection with said spherical member and adapted to constrain said grinding wheel against rotation about the axis of said shaft; a work holder for supporting therein a work piece in grinding engagement with said grinding wheel, means independent of said work holder and of a work piece supported therein for constraining said grinding wheel to a predetermined position of angular deflection relative to a plane perpendicular to the. axis of ro tation of said shaft; and said constraining means pro- 1 viding a fulcrum for oscillation of said grinding wheel thereon as an axis.

14. In a grinding machine, in combination, a rotary driven shaft; a grinding wheel mounted on said shaft in dr ven connection therewith; said grinding wheel being also mounted on said shaft for free and limited oscillation laterally on and about an axis perpendicular to said shaft while said grinding wheel is being rotated by said shaft; a work holder for supporting therein a work piece in grinding engagement with said grinding wheel; and mechanism independent of said work holder and of a work piece supported therein for forcing said grinding wheel laterally to and maintaining the said grinding wheel in a predetermined deflected position at an angle to a plane perpedicular to the axis of said shaft.

15. In a grinding machine, in combination, a driven shaft; a grinding wheel mounted on said shaft in positive driven connection therewith for rotation by said shaft about the shaft axis as a center; said grinding wheel being also mounted on said shaft for free and limited oscillation laterally on and about an axis .perpendicular to the arms of said shaft; a work holder for supporting a work piece therein in grinding engagement with said grinding wheel; and deflecting members engaging with said grniding wheel and being adapted to force said grinding wheel to and maintain it in a deflected position on said shaft at a predetermined angle to a plane perpendicular to the axis of rotation of said wheel during rotation of the wheel by said shaft.

16. In an optical lens grinding machine, in combination; a frame structure; a rotary driven shaft mounted on said frame structure; a circular grinding wheel mounted on said shaft for rotation therewith; said grinding wheel being also mounted on said shaft for deflection laterally thereon about an axis perpendicular to the axis of rotation of said shaft; said grinding wheel having a peripheral grinding surface therearound formed with a lens edge beveling groove therein and therearound concentric with the axis of rotation of said grinding wheel; the portion of said grinding surface between said groove therein and an adject side of said wheel being formed to provide a lens edge grinding surface; rotatable work holding means mounted on said frame structure adapted to mount therein a lens blank for rotation thereby about an axis generally parallel with the axis of rotation of said grinding wheel; said work holding means being mounted and supported from said frame structure for movements to and from an operative position with the peripheral edge portion of a lens blank mounted therein held in grinding engagement with either said beveling groove or said edge grinding portion of said grinding surface of said grinding wheel; grinding wheel deflecting means supported from said frame structure for forcing and maintaining said grinding wheel deflected laterally to a position at which the forces acting thereon to restore said wheel to position in a plane perpendicular to the axis of rotation of said wheel are balanced by the deflecting forces applied thereto to cause said grinding wheel to float in a condition of balance for free oscillation laterally thereof independently of said shaft; and mechanism supported from said frame structure for effecting positive oscillation of said grinding wheel.

17. In the combination as defined in claim 16, said grinding wheel oscillating mechanism being mounted for movements to and from position in operative oscillating association with said grinding wheel; and means for selectively moving said oscillating means to or from operative association with said grinding wheel.

18. In the combination as defined in claim 16, said grinding wheel oscillating mechanism including a push rod mounted and supported from said frame structure for reciprocation axially with one end thereof being engaged against the adjacent side of said grinding wheel; and a driven cam in operative engagement with said push rod for reciprocating said rod.

19. In the combination as defined in claim 16, said grinding wheel oscillating mechanism including a push rod supported from said frame structure and being mounted for axial reciprocation with one end thereof engaged against the adjacent side of said grinding wheel at a location offset from the axis of rotation of said grinding wheel; a spring loaded push rod supported from said frame structure and being mounted for axial reciprocation with one end thereof engaged at the adjacent side of said grinding wheel at a location thereon diametrically opposite said first mentioned push rod; and a driven cam supported from said frame structure in position engaged with said first mentioned push rod for reciprocating said rod to effect oscillation of said grinding wheel.

20. In the combination as defined in claim 16; said grinding wheel oscillating mechanism being comprised of parallel push rods reciprocally mounted in positions with the inner ends thereof engaged with the adjacent side of said grinding wheel at diametrically opposite locations thereon; mechanism for reciprocating said push rods to oscillate said wheel on and relative to said shaft; and said push rod reciprocating mechanism being mounted on said frame structure for movements to and from position in operative association with said push rods.

21. In the combination as defined in claim 16; said grinding wheel oscillating mechanism being selectively adjustable to cause said mechanism to oscillate said grinding wheel through different predetermined degrees of oscillation, respectively.

22. In the combination as defined in claim 16; said work holding means being adjustable for selectively positioning a lens blank mounted therein axially relative to said bevel groove for grinding engagement in said groove; and operator controlled means for selectively adjusting said work holding means.

23. In a grinding machine, in combination; a frame structure; a rotary driven shaft mounted on said frame structure; a grinding wheel mounted on said shaft in positive driven connection therewith for rotation about the axis of said shaft; said grinding wheel being also mounted on said shaft for free and limited oscillation laterally about an axis perpendicular to the axis of said shaft; a set of push rods mounted on said frame structure for reciprocation in positions with the inner ends thereof engaged against the adjacent side of said grinding wheel at diametrically opposite locations thereon; a support structure pivotally mounted and supported from said frame structure; a driven cam rotatably mounted on said support structure and being movable therewith as a unit; said support structure and cam being mounted relative to said push rods whereby in one position of said support structure said cam is in operative engagement with one of said push rods and in another position of said support structure said cam is disengaged from such push rod; and operator controlled means mounted and supported from said frame structure for moving said support structure and cam as a unit to operative position with said cam engaged with such push rod.

24. In the combination as defined in claim 23, the push rod of said set of push rods that is not engageable with said cam being spring loaded for biasing said wheel and cam engaged push rod through a return stroke.

25. In a grinding machine, in combination, a frame structure; a rotary driven shaft on said frame structure; a grinding wheel mounted on said shaft in driven connection therewith for rotation thereby; said grinding wheel being also mounted on said shaft for limited oscillation laterally independently of said shaft about an axis perpendicular to the axis of the shaft; mechanism supported from said frame structure and including a reciprocal member for oscillating said grinding wheel on and relative to said shaft; a support structure mounted on said frame structure for swinging toward and from an operative position relative to said reciprocal member; cams rotatably mounted on said support structure for selective engagement, respectively, with said reciprocal member when said support structure is in operative position relative thereto; each of said cams being formed to actuate said reciprocal member through a stroke of different length; operator controlled means for selectively positioning any one of said cams on said support structure for operative engagement with said reciprocal members; and an independent operator controlled means supported from said frame structure for swinging said support structure to and from an operative position engaging a cam with said reciprocal member.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 152,442 Walters et al June 23, 1874 162,010 Bannister Apr. 13, 1875 203,762 Patterson May 14, 1878 294,847 Burridge Mar. 11, 1884 510,938 Seger Dec. 19, 1893 845,687 Brown Feb. 26, 1907 997,764 Eggers July 11, 1911 1,254,253 Marchant Jan. 22, 1918 1,269,680 Bugbee June 18, 1918 1,386,988 Burlew Aug. 9, 1921 1,619,358 Maynard Mar. 1, 1927 1,647,722 Baker Nov. 1, 1927 1,651,533 Maynard Dec. 6, 1927 1,666,746 Maynard Apr. 17, 1928 1,672,573 Maynard June 5, 1928 1,679,201 Baker et a1. July 31, 1928 1,902,527 Schumacher Mar. 21, 1933 1,976,233 Kosfeld Oct. 9, 1934 2,537,792 Schloss Jan. 9, 1951

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