US1666746A - Bevel-edging machine - Google Patents

Description

A. E. MAYNARD BEVEL EDGING MACHINE Filed May 28, 1924 4 Sheets-Sheet 1 INVENTOR (LS-magnum.

Ap 17, 1928. A. E. MAYNARD BEVEL EDGING MACHINE Fil ed May 28, 1924 4 Sheets-Sheet 2 INVENTOR Cl. 8. magnum] INVENTOR 4 Sheets-Sheet 5 w l" 2 5% a? April 17, 1928."

A. E( MAYNARD BEVEL EDGING MACHINE Filed May 28, 1924 J2). -fimaynard; A ATTRNEY I April 17, 1928. 1,666,746

' A. E. MAYNARD BEVEL EDGING MACHINE Filed May 28, 1924 4 Shags-Sheet 4 ir u l H I. r

u /02 m M3 107 [.03

\ INVENTOR Patented Apr. 17,1928.

ALBERT E. MA YNARD, OF SOUTHBRIDGE, MASSACHUSETTS, ASSIGNOR TO AMERICAN OPTICAL COMPANY, OF SOUTHBBIDGE, MASSACHUSETTS, A VOLUNTARY ASSOCIA- TION or MASSACHUSETTS.

Application filed May 28,

The present invention relates to ophthalmic lense'dging machines and has particular reference to a bevel edging machine.

An important object of the invention is'to provide a bevel edging machine embodying a grinding element,- means to rotate the grinding element, a lens holding element, means to rotate the same, means-to compensate for displacement due to change in plane otlier form of stone mounting.

of lens as it rotates, a shape controlling pattern, means to regulate'the sizeof the shape, means to feed the lens and lens carriage to ward the stone step by step, means to stop the feed and to rotate the lens several times Without the feed to give the final grinding motion to throw the lens holder away from the stone, and means to stop the rotation of the lens.

Another very important object ofthe invention is'to providea bevel edging machine that will grind both surfaces of a lens simultaneously, the said machine including a stone having a substantially V shaped groove formed therein, the said stone being --n1ounted on a rotary shaft by means of a flexible connection and means for holding and rotating' the lens in the groove whereby the stone I p twisting movement upon the shaft and stone.

mountingwill be moved torsionally to accommodate for displacements due to the various changes in plane of the lens as it rotates.

, A still further object of the invention is to provide a bevel machine including a rotary stone shaft-and a rotary lens clamping shaft,

' neither one of which is movable relative to the other during the grinding operation.

Other objects and advantages of theinvention Will become'a'pparent during the course of the following description.

In the drawings, wherein like numerals are employed to designate like parts throughout the same:

Figure 1 is a front elevation of my improved machine. I Figure 2 is a side elevatlonthereof.

Figure 3 is a detail elevation illustrating V g millimeter under size while the other of the said lenses was approximately one millimethestep by step controlling mechanism.

Figure 4 is aside elevation of one torn of stone mounting employed. I Figure 5 is a sectiontaken on line 55 in Figure 4. 7

Figure 6 is a side elevation of a slightly different form ofstone mounting employ- 'ing the same principle.

B'EvEL-EnGINe MACHINE 1924. semi No. 716,423.

Figure 7 is a section taken on lines 77 in Figure 6.

Figure'8 is a side elevation of a slightly modified form of stone mounting."

Figure 9 is asection taken on line 9-9in Figure 8.

10mm) VISTAZTES fearENT 1 OFFICE- ""Figure 10 is a similar section showing a mod fied construction.

Figure 11 is a side elevation of still an- Figure 12 is a section taken on line 12-l2 thereof;

Figure 13 is a fragmentary sectional de-.

tail of a slightly modified form of mounting shown in Figure 12.

Figure 14 is a. sectional view showing the relation of a plano lens to my form of stone mounting;

position of the stone and lenses of the convex and concave type.

Figure 16 isa View of a lens.

showing the action of the stone upon a partial rotation of the lens. 1

Figure 18 shows a still further step inthe rotation of the lens clearly illustrating the Figure 19 is a modified form of lens clamp. Prior to this invention many attempts have been made to bevel both surfaces of an ophthalmic lens simultaneously. The chief Figure 17 is a View similar to Figure 15.

' Figure 15 is a top plan View of the initial dilficultyhas' been that the finished lens has 5 .difference in the size of the two lenses. In

other Words, the lenses were ground on a machine with the shape and the size control mechanism untouched during the grinding of the two lenses and upon examination the lenses ,did' not measure to. standard size. One of the lenses was approximately one ter over size. As far as can be ascertained, this same difliculty of grindlng either under size or oversize lenses has been met withon all machines employing either an axially movable stone or an axially movable lens carriage.

, axially movable stone.

In the present invention, I employ a stone which may be torsionally moved with respect to the stone shaft so that it will accommodatc itself to the displacements caused by the difference or change in planes of the lens as it is rotated. By a torsional movement, I mean a stone which adapted to be rocked and twisted with respect to its drive shaft or axis so that points of the periphery may be so arranged that they will not fall in planes at right angles to the axis of rotation.

The main difference between my machme and the prior art constructions is that I em ploy a stone which may be torsionally moved while the prior art constructions used an The axially movable stones or carriages may be movedtransversely to the machine but prior to my in vention no stone has ever been employed wherein the stone may follow the lateral displacement caused by the changes in planes in the lens being ground and also may be twisted at the same time to follow the exact curvature and angle of that portion of the lens within the groove at the time the stone is being moved.

In the drawings, wherein for the purposes of illustration l have shown a preferred embodiment of the invention the numeral 20 designates a grinding element used in accordance with my invention. The grinding element is shown in l igures 1, 2, 4 and 5 and comprises a preferably onepiece stone having a sul'istantially V-shaped groove 21 formed in its periphery. The stone 20 is provided with an enlarged central opening in which is adapted to be mounted a flexible member which is clamped to the inner periphery of the stone by the clamps 23 and to a drive shaft 24 by means ofthe clamps 25. The flexible member 22 may be of any desired material. such as fabric, rubber composition or the lilre provided that the material will be su'liiciontly strong to support the stone 20 to rotate the same while at the same time it must be flexible enough to permit of the stone being rocked and twisted on the drive shaft 24. In other words, the flexible co'nnectin means 22 must be of such a nature that the stone and stone mounting may be twistingly moved to compensate for the lateral displacements caused by the rotation of the lens to be ground within the groove 21. Thus the stone 20 is mounted for a tvv'isting movement and not adapted for an axial movement in view of the fact that the drive shaft 24 rotatably mounted but not laterally movable. In other words, all movement of the stone 20 must be taken care of by the flexible connecting member 22 and not in any way by the drive shaft 24 eX- ccpt forthe fact that the drive shaft 24 rotates the said stone through the clamping member 25 and connecting element 22. The drive shaft 24 is journaled in the bearings 26 supported on the frame 27. The pulley 28 is keyed to oneend of the shaft to drive thesame.

The form of lens carriage illustrated in the drawings is not absolutely necessary to the operation of my improved machine as the action of the stone'andmounting would be the same in any case while the lens is held within the groove of the stone and rotated. l have, however, shown one form of lens carriage which may be used with satisfactory results.

The lens carriage comprises the casting 29 journaled through one end of which is-the shaft 30 on which the said casting is pivotally and partially slidably mounted. The shaft 30 has at one end the gear 31 which meshes with one of a train of gears 32, the saidtrain of gears 32 deriving power from the gear which is keyed to the opposite end of the drive shaft 24. The casting also has journal-ed therethrough the opposed aligned shafts 34 and 35 respectively, the said shaft 34 being both rotatably and slidably mounted in the said casting while the shaft 30 is a drive shaft imparting rotary motion to the lens 36 which. is adapted tobe received within the groove in the stone, the said shaft not being laterally movable through the casting. The shaft .34 is connected with the rocker-arm 37 which is pivoted on the post 38 while the opposite end thereof is pivoted to the plunger which is received within the recess formed in the carriage in the end of whic-his disposed a coil spring 40. The operating lever 41. is adapted to slide the plunger 39 within-its recess thus-con'ipressing the spring 40 at the same time the rocker arm 37 which will move the shaft 34 thus separating the two aligned shafts to allow of the insertion or removal of the lens 36 from between the pads 42 car ried by the ends of the opposed shafts.

In order to rotate the opposed shafts 34 and. 35 respectively, the gear 43 is carried by. the outer end of the shaft 35 and meshes with the intermediate oridler gear which in turn meshes with the gear 45 which is keyed to the sleeve 46, the said sleeve 46 being received on the shaft 30. Obviously, upon rotation of the shaft 30 through the train of gears 82, gear 31 on the shaft 30, the gear 45 at the opposite end thereof will likewise be rotated and through the idler 44 the gear 43 will be rotated, thus revolving the shafts 34 and 35 carrying the lens 36 to be ground. In orderto rotate the sleeve 45 v-rith theshaft 30 the clutch 47 designated in its entirety is provided'and comprises a sta tionary section 48 keyed tothe end of the shaft and a movable section 49 movable into and out of engagement with the stationarv section 48. the said movable section being moved into and out of an operative position by means of a pivoted yoke 50. When the eLBMJAB two sections of the clutch. are disengaged the operation of the-lens clampingvshafts will be-stcpped and whenithe sections-"are moved into engagement with each other; the opposedehaftsB l and 35willberotated as abovepointed out;

In'order to regulatetheshape theileiis beingground the former 51.is provided and is held in position by means of a lock nut 52.

Although ,in the present instance 'I have illustratedbut a sii'igle' former, a gangof formers maybe provided if desnred'although the arrangement I have shownqwill; prove entirely satista'ctory as any shape of former r may, readily be placed inflpositionupon the machine for cooperation with the contact shoe 53 which is carried by the screwjthreaded shaft 54., The micrometer adjustmentl55 is provided to control the size of the shape being ground, "the siz'e being indicated on the scale,56 on the micrometer adwstment.

The spring 57 is connected to .thepivoted carriage 29 at one end andttoa stationary portion of the frame27 .at the other end so that the pivoted carriage .will normally be urged toward the stone sothat the-lens36 will be under springltension when inthe groove 21 of the stone 20. Likewise the .former or: attern 51'whicliiscarriedb the shaft'35 willcontact with the shoe. 53and as in the. case of elliptical or irre'gular shaped formers will cause the earriageto he moved to and fromtlie stone. so thatthe same shape of lens will be ground 'as-v the shape of the former used;- Therefore, the advance ofthe lens anducarriage toward the stone- ,will:;be

determined by, the rapidityvwith whichfthe formercontact shoe c53'ismoved and to govern this movement Imount the 'contaet'shoe 53 on a pivot'edcarriage'58 which rocked on the pin-69. The pivoted.- carriage .58 is provided with a lip -.which. is;;clearly shown in- FiguresQ and, 3 of the drawings and is so arranged that it is adapted rest upon' a portion of the frame 27 in -sucha manner that ,ijnovementthereof isrestrictd in that direction. In Figure 3 1s shownm full lines the position of the pivoted carriage contact shoe and shape former when the lip 60 is not in engagement with the frame 27 and in dotted lines is illustrated thetposition of the carriageaiid other parts when the-lips 60 are in contact with the frame',- Itis tobe understood that'it is the rocking movement of this carriage 58 that controls the advance or step-by-step feed of the lens toward the stone during the grinding operation andthat when the lip 60 eonta'cts with the frame the lens no longer advances toi vardthe stone but is held in oneposition and is allowed .to rotate several times for the.,.final finishing,'

shaping and grinding rev-olutionsg 1. v

The advance of the; lens toward the-stone is controlled-by the continuous curve cam 61 which is carriedionthe shaft 62," The came taken place.

SQC011(l C2Lll1'71 which 1s,lik ewi'sekeyed to the r .61 has the high spot '63 and the curve grad ually comes toward the center ofzrotation of the shaft 62' until thesmallest or lowest. portionof the cam is at about 64., ;A hardened member is carriedby the pivotedcarriage 58 and is adapted to ri deupon, the taceof I the, cam as is clearly illustrated in Figure 3.

WVhen the hardened portion 65. ision'the high -Spot,63 the lens carriage will be farthest away from thestone andras thecain 61 rotates the =member 65 will rideldown, untilthe point 6% is reached, atWvhichQpoint the lip, 60 will rest upon theiframej and the cam and ,member 65 will no longer contact; ,,During the time that the cam 64 is on the low spot the lens will be a permitted to rotate several times atthis fixed spot-sothat the final finishing and shaping revolutions will take place, after which the member 65:W1ll againJride upon'the; high spot thus, throwing the. lens 1 away from the stones g H '2 In order to rotate the cam 61 the geari66 iskByed-O11 the shaft 62 and meshes with the'gear 67 carried-on.these'cond shaft"68 which carries. the i gear 69 which meshes with the gear-W0. IThe g'eai270-is o'n the-shaft 3 and therefore-upon rotation-,oftlie said shaft,- the 'sha't-t'68 willbe rotated thus causing the gear 67 to: rotate the gear 66, thus operating the cam. This gear arrangement causes the;

camto-berotated slowly and gradually from the high spot ,to the, low spot.

To sin'ipli y; the operation of themachine I provide' in addition to the automatic throwolitmeans an automatic clutch to stop the shaft 7 iis a yoke 7-5 :which has engagement by means of the pins76gwith a movable clutch section 49v and is adapted to control the throw ottheinovable clutch section into.

and out of engagement with the stationary clutch, section; The spring-pressed finger 76; is adaptedto :engageyina an opening formed i i-the pivoted yoke 75. The spring 'pressedfpini76i. is carriedaby the arm 77 keyed to the. shaft 7 4 so that upon movementof the shaft 74 the'iarm 77: will .be moved.

At the beginningofi the grinding operation the pin 7 6,.,is disengagedfroin theyoke 7 5 and. due to an internalspring ithe JDOWIblG clutch is inovedjinto' engagement with the stationary section .ofthe clutchiand the lens carriage is rotated. As: the ,cam.71 grad ually rotates the arm 72 will bemovedinwardly toward theblens .u:n.ti1@a-'point has been reached when the spring pressed pin 76 will snap into place in the recess formed in the yoke and when the cam reachesthe high point and just passes over the same the arm 7 2 will be snapped inwardly so that the pivoted yoke will cause the movable section of the clutch to become disengaged, thus stopping rotation of the machine.

In order to line the lens up wit-h the groove in the stone the pivoted lever 78 is carried by the frame 27 and has engagement, with the pin 79 on the lens carriage 29. In view of the fact that the lens carriage 29 may be slidably mounted on the rotatable shaft 30 upon manipulation of the lever 78, the lens and groove in the stone may be placed in perfect alignment. It is understood, however, that the lens carriage does not have any lateral movement during the grinding operation but is merely moved laterally when placing the lens in position for grinding as just pointed out.

In Figures 14, 15, 17 and 18 is shown the action of the stone during the grinding operation. It is to be remembered that the lens to be ground is fed straight into the groove .of the stone.v In Figure 14 the lens 36 is a piano lens and obviously is in perfect alignment with the stone during the grinding operation and the stone does not twist or tilt. In Figures 15, 17 and 18-, however, a dinerent type of'lens 80 is being ground. In Fig ure 15 is shown the initial position of the lenses in which the stone is perfectly perpendicular. The type of lens herein shown is a convex-concave lens of elliptical shape and as is clearly shown, the surfaces do not follow any single plane. In Figure 17 is shown the position of the stone upon a partial revolution of the lens within the groove, illustrating that the same displacement of the stone takesplace in the rear as at the front, that is, if the front of the stone is moved to the right or left of an inch caused by the displacement of the lens due to changes in the plane of the lens upon rotation the rear of the stoneat a point in the same axis as the front will likewise be moved of an inch. It is to be noted, however, that the movement in the front is in the opposite direction to that in the back of the stone. In Figure 18 is still another position of the stone upon rotation of the lens within the groove. In this position in addition to being moved in a longitudinal planethe stone is also tilted from its vertical plane so that no two points in the periphery of the stone lie in the same plane at right angles to the axis of rotation of the stone. Figure 18 clearly shows the twisting movement of the stone during the grinding operation. It

is due to this rocking and twisting movement.

of the stone that I am able to edge a lens satisfactorily, with the result that I get a lens that is ground absolutely true to shape and accurate in size. When employing the axially movable stone it is impossible to ob-' tain the position of the stone as is shown in Figure 18, while with the stone having a flexible centre the displacements caused by the change in plane of the lens immediately causes the stone to assume the required position to give an absolutely true reproduction of the form used and size required.

In Figures 6 and 7 is shown a slightly modified form of flexible connecting means between the stone 20 and the shaft 2a. In this instance spring meansa-re employed and I preferably unite two spring sections to form a single unit 81. In other words, I take two spring sections, clamp them back to back, and then securely clamp them to the shaft by means of the clamp .82 which is keyed to the shaft 24 and to the stone'20 by means of the clamps 83. The spring sections being formed in this manner will have the tendency to counteract the action of the other spring section, thus normally holding the stone in vertical plane.

In Figures 8, 9 and 10, instead of a fleX- i-ble fabric centre or flexible spring centre,

I employ pivoted links. The links forming the chain 84 are supported at the hub 85 by meansjof the transversely arranged pins 86 while they are supported on the plates 87 by means of the adjustable screw threaded shafts 88. The lock nuts 89 on the ends of the shafts 88 permit the adjustment of the links when in use. It will be seen that the shape of the plates 87 are suchthat a wrench may be placed between the stone and the platesto facilitate adjustment. In Figure 1 support the raceway 94 between which are the balls 95 which are adapted to rest upon the second raceway 96. A'driver 97 carried by the shaft '24 causes the stone to be rotated with the shaft.

In Figure 12 is shown one method of honing the stones and includes a pair of plates 98 having the inwardly extending flanges 99 which are slidably mounted on the shaft 24. Normally, during the grinding operation, the plates 98are slid away from the stone so'as not to hinder the twisting movement thereof but when it is desired to hone the stone the plates are moved toward each other until the stone is firmly clamped in position for honing. The form of hone I employ is preferably in a circular disk form 100 and has the bevel edge'adapted to be received within the groove 21 of the stone. The form of hone shown in Figure 12 is held between the oppo3ed shafts 34 and35 of the moves to-the left, the diametrically opposed" pads 42 and the machine is setin' operation until the bone has removed the required amount of material from the stone. The hone may then be removed from between the opposed shafts and it will be found that-the faces of the groove 21-have'been-sufiiciently smoothed for the edging "of lenses. In Figure 13 is shown a double raceway 101' instead of the single raceway as "in Figure 11.

In Figure 19 the'lens'carriage is adapted to be twistingly moved-instead-of the stone. Obviously the same result will be had when the lens is held in clamping means that may be twistingly moved to allow the 'lens'to adapt itself within the groove of the stone used for the edging.

From the foregoing, it will be gathered.

that I have'provided a bevel edging machine employing a stone that is mountedside of the stone will move to the right, and

vice versaas is clearly shown in Figure 18,

but the stone will be tilted as wellas rocked so that all the points in the peripherywill fall in different'planes not at rightanglesfto the axis of rotation. This stone bevels the edge of a lens absolutely true and accurate both as to shape and as to size, and'in addition, the ridge between the two surfaces of the lens will be ordinarily in the middle so that the lens will present a neat appearance -when mounted in an eyeglass or spectacle mounting.

It is to be borne 'in mind that neither the lens carriage nor the stone shaft has any axial movement during the grinding operation and that all displacements caused by the rotation of the lens in the groove are taken care of by the twisting movement of the flexible center of the stone connecting the stone and the drive shaft.

The lens to be ground is gradually fed toward the stone until a certain point has been reached at which point it is held against further movement and allowed torotate several times so as to give the final sizing and finishing revolutions after which the lens is automatically moved away from the stone and the clutch automatically stops rotation thereof.

It is to be understood that the form of the invention herewith shown and described is to be taken as the preferred embodiment of the same and that various changesin the shape, size and arrangement of the parts maybe resorted'to without departing from the spirit of the invention ,or' the scope of thesubjoined claims. I 1 v Referring more particularly to Figure'19, the numeral 102 designates a grinding element' which is'neither axially nor twistingly movable upon or withrespect to its drive Shaftj-fl In the present instance I employ a,

lens holder '103 in .its entirety, "which is] adapted to'be twistingly moved by'reason of the contact of the lens 104 within the groove of the grinding element 102- The lens-holding element comprises the separable shafts 105 and 106, respectively, the shaft 105 being carried by a' suitable spider or the like 107, which has connection with the flexible member 108. Theflexible member 108'is centered in its center 109 on the shaft 110, which has atone'end the drivepin on 111 and at the opposite end, that is, the end disposed on the-other si'de 'of the iiexibleccnter 108 the ball bearing 112. The

roller bearing 112 is adapted to ride on the inside of the spider 01' cup 107,"so that the .lens will havea drive, while at the same time it maybe twistingly'moved. The, op posite shaft 106 is provided with the universal joint 113 and thecam operating mechanisn'r 114: adapted to separate the" opposed shafts when it is-desired to insert or remove a lens for edgmg. r

' It isclear that either'the stone or the'lens holder maybe monntedto give this twisting movement. either one giving the same result,

although Iv haveshown the stone so mounted as ,my .preferredi arrangements Furthermore, the form of.-,lens carr1age "or holder employed is DOtESSGHtIStl tothe' operation ofthe machine. :as it-is notabsolutely neces-,

sary to use a carriage employing the step by step feed, the kick back, or the automatic cluch for disengaging the clutch to stop r0- tation of the lens, as the same type of stone will work equally well with a lens holder for holding the lens in' contact with the stone, a pattern to regulate the shape and size of the lens being edged, and means to hold the lens against the stone.

Furthermore, any typejor shape of lens may readily be bevel edged on this type of machine. A toric, lens has a different curve in the two major meridians so that the displacement of the stone will be the differences in planes of-the lens at the ends of the meridians. The same holds true of a cylindrical lens, while planos and sphericals have the same curve in the two major meridians; hence there is no displacement between the two meridians, while in the torics and cylinders there is a displacement as the lens is rotated in the groove of the stone.

It will be noted from inspection of Figure 18 that the stone has a double displacement, that is, it is rocked or twisted in two planes at right angles to each other so that no two points of the periphery of the stone fall in a plane at right angles to theaxis of rotation.

' Having thus described my invention, I claim:

1. In a lens edging machine, a grindstone shaft, an annulargrindstone ring having a groove in its grinding face, lens clamps holding a lens with its edge extending into the groove in the grindstone, means for 1'0- tating the shaft, means for rotating the lens clamps, and a flexible member connecting the shaft and the grindstone annular ring Whereby the engagement of the edge of the lens in the groove in the grindstone as it rotates therein will bend the flexible member to permit the grindstone to adjust -itself to the change of position caused by the change of plane of the point of contact of the edge of. the lens as it rotates.

In a lens edging machine, a grindstone shaft, an annular grindstone ring having a groove in its grinding face, lens clamps holding a-lens with its edge extending into the groove in the grindstone, means for rotating the shaft, means for rotating the lens clamps, and a yieldabl-e diaphragm plate connecting the shaft and the grindstone annular ring whereby the engagement of the edge of the lens in the groove in the grindstone as it rotates therein will bend the yieldable diaphragm plate to permit the grindstone to adjust itself to the change of position caused by the change of plane of the point of contact of the edge of the lens as it rotates.

3. In a lens edging machine, a grindstone shaft, an annular grindstone ring having a groove in its grinding face, lens clamps holding a lens with its edge extending into the groove in the grindstone, means for rotating the shaft, means for rotating the lens clamps,

and a fabric diaphragm connecting the shaft and the grindstone annular ring whereby the engagement of the edge of the lens in the groove in the grindstone as it rotates therein will bend the fabric diaphragm to permit the grindstone to adjust itself to the change of position causedby the change of plane of the point of contact of the edge of the lens as it rotates. a

4-. In a lens edging machine, a grindstone shaft, an annular grindstone ring having a groove in its grinding face, lens clamps holding a lens with its edge extending into the groove in the grindstone, means for rotating the shaft, means for rotating the lens clamps, and a flexible member connecting the shaft and the grindstone annular ring whereby the engagement of the edge of the lensiin the groove in the grindstone as it rotates therein can twist the flexible member in more than one plane to permit the grindstone to adjust itself to the change of position caused by the change of plane of the point of contact of the edge of the lens as it rotates.

5. In a lens edging machine, a shaft, a grinding element on the shaft having a groove in its grinding face, a lens holding element for holding a lens with its edge projecting into the groove of the grinding element, a shaft 011 Which it is mounted, means for rotating-the elements, means for urging one element towardsthe other, and a flexible member between one of the elements and its shaft whereby the engagement-of the edge of the lens in the groove in the grinding element as it rotates therein will bend the flexible element to permit the grinding element to adjust itself to the change of position caused by the change of planeof the point of contact of the edge of the lens as it rotates.

ALBERT E. MAYNARD.

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