US2268159A - Lens surfacing machine - Google Patents

Description

Ammwm CQPY J. J. M CABE ETAL 2,268,159 LENS SURFACING MACHINE Dec. 30, 1941.

Filed March 27, 1941 v 4 Shets-Sheet 1 JOSEPH J. McCABE GEORGE C SCH ELLING INVENTORS BY fig,

ATTORNEYS J. J. M CABE ETAL LENS SURFAGING MACHINE Dec. 30, 1941.

Filed March 27, 1941 4 Sheets-Sheet 2 JOSEPH J. Mc. CABE GEORGE C.SCHELL.|NG INVENTORS @TTORNEYS? 30,1941. J, MoCA BE EI'AL "2,268,159

mus suamcme mourns Filed March 27, 1941 4 sheets-sheets Fla:

JOSEPH J. McCABE' GEORGE C.SCHELLING INVENTORS ATToR'NE Dec.30, 1941.

J. J. MCCABE ETAL 2,268,159

LENS SURFACING MACHINE Filed March 2'7, 1941 4 Sheets- Sheet 4 as JOSEPH J. M; CABE GEORGE c. SCH ELLING INVENTORS ,6 ATTORNE mini can 30,]19415 r Joseph. J. McCabe,

Sohelling,

N. Ya,

Rochester, and George C. lrondequoit; Bausch azvLomb' Optical N. Y., assignors to Company, Rochester,

a corporation of New York Application March27,1941,Serial No. 385,472

' :11 Claims. (01. 51-131) The, invention relates to lens surfacing. machines and more; especially is concerned with that type of machine whereinv a reciprocating headisusedto:reciprocatea lens over a. rotatinglapa I I Anvimpor-tant.objectiof the invention is the provision, of: a. machineof" this character which utilizesrnechanica'l means to reciprocate a lens overwaqrotatingslap with armovement which simulates'that given aslensby arr-operator of a hand surfacing machine whilemanually reciprocating the pressure handle" thereof. to surface a lens.

Another object. of the .inventionresides in providing adjustable eccentric means for controlling the reciprocating movement of the 1 polishing head of a,lens-surfacingvmachine wherein the stroke thereof is determined by, the position of an adjustable ball: havinga drive stud formed thereon; r

The inventionshas as another'objectthe provisionofjanoveli mountingmeans permitting the polishing head of awlens surfacing machine to beangled in; a vertical plane .located transversely of 1 the machine; and to be "adjustably positioned 'aboutran axis movable-in that plane as wellas the provision: ofmeans for varying the positionof an arm carried bythe polishing head for supportingwork-engaging means; i

AIurther object oftheinvention is to provide a. lens surfacing: machine having gear means adapted tooperateawlever systemfor lowering andir'aising the polishing head of a machine into and out of operatinguposition together with means formaintaining work engaging means carried by the headin adjustable pressure contical effect without limiting the improvements in their useful applications to the particular constructions which, for the purpose of explanation, have been made the subject of illustration. To this end the invention is disclosed in the following manner, wherein:

Figure 1 is a perspective view of our lenssurfacing machine taken from a side thereof.

Figure 2 is a perspective view of the lens surfacing machine taken from the front thereof. 7 Figure 3 is a longitudinal vertical section of the machine with certain parts thereof removed. Figure 4 is a transverse vertical section of the machine with certain parts thereof removed.

There is shown in Figure 1, like reference characters being used throughout the drawings to designate like parts, a machine engaged in surfacing a lens having a spherical surface. It will be appreciated, however, that through the use of suitable attachments our machine may be adapted to the polishing of cylindrical surfaces.

The machine comprises a hollow base 20 having tact with" a'lensblockrby aconstruc'tion designed" to leave the pressure; adjustment unaffected by the-actuation of the head: raising and lowering I means; a

Yet; a further object of the' invention is to provide a lens :surfacingjmachine of a simple design which maybe readilyrjembodied rable and: eflicient structure;

in w a strong, du-

With. these and other objects in view which may be incidentlto oursimprovements, the inven.

tion consists inthe partsand combinations to be hereinafter set forth and claimed, with the understandingthat the. 1 several necessary elements comprising" our; invention maybe varied in construction, proportion and arrangement? without departing from-the spirit of 'the invention orexceeding the, scope of the appended claims.

In order to makeour invention more clearly understood,z we have :shown in: the accompanying drawings-means for carryingcthe same into praca top 2| and bottom 22 which latter members are provided with pairs of aligned bearings 23 within which are journaled the vertical work spindle 2i, intermediate shaft 25 and stroke control shaft 26. The function of the shafts 25 and 26 will presently appear. Suitable bearing covers 21, secured to the top and bottom of the base, are provided for the bearings 23. Also journaled in the base in suitable bearings (not shown) is a horizontal drive shaft 28 one end of which extends beyond the base and is provided with a drive pulley 29 around which is a guard 30 carried from the base. A spiral gear 3| and worm 32, the latter shown in dotted lines in Figure 3, are fixed to the drive shaft 28. Gear 3| meshes with a spiral gear 33 fixed to the work spindle while the worm 32 cooperates with a worm 34 fixed on the intermediate shaft 25, these means being employed to drive the work spindle and the intermediate shaft.

Foroperation, the machine is adapted to be placed upon a table or stand which carries an electric motor connected by any conventional drive means, for example a belt, to the drive ventional grinding or polishing lap 31 best shown in Figure 1. Use is made of the usual fan 38 fixed to the work spindle 24 above the top of the base in machines of this nature to prevent abrasive from entering the bearings of the apparatus. As best noted in Figures 2 and 3, lugs 39 are formed upon the top of the base for detachably engaging the ribs or flanges on the exterior of a conventional splash pan 40 which surrounds thespindle during operation of .the machine. A suitable opening bottom of the pan 40 to' permit it to be placed is formed in the over the work spindle and to be seated upon the' base top 2| of the machine.

Cooperating with the work spindle and lap is a hollow polishing head 4| which functions to.

maintain a lens on the lap in pressure engagement therewith and to cause the lens to be moved back and forth over the lap with a suitable grinding motion. To this end the polishing head 4| is mounted above the base by a construction which makes use of the spaced apart standards 42 and 42 located on the top 2| transversely of the machine. A support member 43 is mounted I between the standards 42 by means of pivot screws 44 to pivot about a horizontal axis which is parallel to the longitudinal axis of the base 28 and which intersects the axis of rotation of the work spindle 24. It is to be noted that the pivot axis of the support member 43 is horizontally arranged and is located above the top 2| of the machine base so that it is substantially tangent to-the center of a lap 31.

The support member 43 15 provided with an extension having a worm gear segment 45 formed thereon for engagement with a worm 46 fixed on a shaft 41 located at right angles to the pivots 44 and carried in shaft bearings 48 provided on the standard 42'. It will be apparent that proper rotation of the operating handle 49 fixed on the shaft 41 will cause the support member 43 to be rocked or tilted about its pivots 44 and angled as desired-in a vertical plane located transversely of the base of the machine. If desired, suitable clamping means may be associated with the structure just described to assure the maintenance of the support member in adjusted positions.

As may be observed in Figure 3 the support member 43 is formed with a bore which is provided with bearings 58 for rotatably mounting the support shaft 5| which is carried by the support member and which in turn carriesmhe polishing head, suitable bearing covers 52 being employed with this mounting. The shaft 5| ex tends above the support member 43 and is adapted to have a head support member 53 loosely mounted thereon between a nut 54 which engages a threaded portion on the shaft located above theshaft support 43 and a nut .55 which engages the upper end of the shaft. Thrust washers 56 are placed between each nut and the end of the head support 53 adjacent thereto. Means for locking the head support 53 in adjusted position on the support shaft 5| comprises a clamp screw 51 which extends through a threaded bore in the wall of the head support and is adapted to engage the support shaft 5|, an operating handle 58 being provided on the clamp screw to facilitate this adjustment.

Head support 53 is the member of the support structure to which the polishing head 4| is directly connected and for this purpose is formed with a projection .or support bracket 59. The polishing head is positioned to surround the end means not only permitswear adjustment but also provides a centering adjustment for the head with respect to the axis of shaft 5|.

As previously noted, the polishing head 4| supports work engaging means. Use is made of an arm 6|, held within a bore in a projection on the head 4| by a clamp screw 62 for slidable and rotatable adjustment with respect to the work spindle, to permit adjustment of work engaging means adapted to be carried on this arm.

A well known manually operated clamp 63 is.

fixed on arm 6| and is adapted to support a conventional type of pressure pin, for example the resilient pin 64, in adjustable relation'to the work spindle. The pin 64, as illustrated in Figure 1, is adapted to contact a lens block 65 having a blocked lens 66 and hold this workag'ainst the lap. I

In lens surfacing machines it is necessary to keep the work in pressure contact with the lap and it is desirable to provide positive means for moving the polishing head into operating and inoperative positions and for locking the head in these positions. The mechanism for raising and lowering the head 4| out of and into a work position is shown in detail in Figures 3 and 4 and comprises a gear train which drives an eccentric connected to a lever system with which is associated spring means for applying pressure to the polishing head. To this end the head support 53, which is usually cast, is provided with a gear box 61 having a suitable cover 68 secured thereto. Gear shafts 68 and 10 are journaled in the gear box and are respectively provided with the drive pinion 1| and driving gear 12 which are in mesh with each other and which are fixed to their respective shafts. The shaft 68 extends through the cover 68 and has a suitable crank 13 secured to its end while the'shaft 10 extends through the opposite side of the gear box and has its end under the polishing head 4| provided with an eccentric 14.

Pivotally secured upon the eccentric 14 is a bifurcated raising link 15 which is provided with an adjustable stop 16. A lever 1/1, is positioned between the forked ends of the {raising link 15 and is pivoted theretob'y a pivot pin 18 which extends through the raising link and to one side thereof, this lever in turn' having one end mounted on a pivot pin 19 held between spaced lugs formed on the head support member 53 ad pressure arm 83 mounted ona pivot 84 located within the head 4|. One end of the pressure arm 83 is provided with a threaded post 85 to which is secured one end of a spring 86, a similar thespring. A contact member 61 isformedat the end: of the pressure arm away from the spring for contact with the end of a slldable pressure pin 60 carried ina guideway formed in the top of the polishing head. This guideway It is threaded at its outer end to receive a pressure screw 60 operated by a hand wheel ii to engage the end of the pressure pin 86 withinthe guideway and to adjust the tension of the spring 06.

In Figures .1 and 3 the pressure head. if is shown in a lowered or operating position. Where such is the case the eccentric I4 is off center with the result that it is out of alignment with pivot pin I6 and-lifting pin 82 as illustrated'in Figure 3. Or toLput it another way, the axis of the. eccentric M is offset from. a plane which passes through the axis of pin 62. and the pivot "for the link 15, lever "and arm 0|. Also when the pressure head is lowered and the pressure pin 6| is engaged with a lens block, the stop I6 is in contact with the bracket 50 and the 01 against their respective fixedly positioned bracket 56 and pressure pin 66, the force of the spring is limited to moving the pressure head downwardly or in a counterclockwise direction I about its pivot 60. This prov-ides the necessary pressure contact between the work and the lap and may obviously be decreased or increased at any time by suitable operation of the hand When the raising link 15 and stop 16 are 10- cated as shown in Figure 3 and the resilient pin expedient assures maintenance of grinding con-, tact during surfacing operations. Obviously adjustment of the stop 16 permits any desired variation for the operating off centered position of the eccentric I4. At the same time it may be noted that actuation of the hand wheel 01 allows variation of the grinding pressure either during operation of the device or while it is at rest.

The ratio between the gears Ii and 12 is so selected that the stroke of the handle for raising the polishing head will move the eccentric 14 through an angle greater than 180 and position. the eccentric somewhat above its location shown in Figure 3 but also in ofl'centered relation to the pivot 16 and lifting pin 02. This just described movement of the eccentric 'llcausesrthe raising link 15 to be moved in a clockwise manner as viewed in Figure 3 about the gear. shaft 10 as a center. First link 16 moves downwardly and to the left and thentupwardly, at first to the leftand then to the right, until the stop I6 contacts the bracket 50. g

The just] described movement of the link 15 will, of course, lift both the lever 11 and arm 6b to which the link is pinned. This results in the spring 66 being allowed to contract and in the arm 64 fully engaging the pin 02 and raising the polishing head Ii about its pivot to the inoperative position iliustrated in Figure 2. It will be apparent that when the polishing head is in its raised and inoperative position that the oil centered location of the eccentric I4 will effectively prevent its downward movement under its own weight and that it will be safely locked in this position. A small amount of play has been shown in Figure 3 between the lifting arm BI and its pin 82 when the polishing head is in operating position. This play has been provided to permit slight movement of the polishing head aboutits pivot 59 during operation of the machine in order to care for the curvature of the lens being surfaced.

Obviously movement of the crank 13 in a reverse direction from that described will lower the polishing head from its inoperative position to the surfacing position of Figures 1 and 3 and will cause the eccentric l4 and link 15 to move in a counterclockwise direction into the operating position heretofore described. In this downward movement of the polishing head the spring 06 will remain contracted until the resilient pin 64 contacts its lens block. Upon continued op-: eration of crank 13 for its lowering stroke, the polishing head and arm 83 will remain substantially stationary relative to the eccentric H and lever 11 so that the movement of the latter will expandthe spring 86 and place it under the tension necessary to create a grinding pressure between the lens and the lap.

In surfacing operations it frequently becomes necessary to remove a lens from the lap for inspection. When such is the case it is highly desirable to resume surfacing under the same grinding.pressure. It will be apparent that the structure disclosed permits the head tobe raised and lowered without affecting the pressure adjustment so that an operator of the machine is assured that the polishing head will develop a substantially constant operating pressure for each setting of the hand wheel 9|.

The polishing head and the work engaging means have been described as adapted for re ciprocation over the lap of the machine. In accomplishing this it is necessary to reciprocate the support shaft 5| with the head locked thereto. To this end, power is taken off the intermediate shaft 25 to drive the stroke control shaft 26 which is coupled to the support shaft 5 i. As best shown in Figure 4, a drive spur gear 92 is fixed to the intermediate shaft 25 to mesh with a driven spur gear 03 fixed on the stroke control shaft 26. Under these conditions it will be apparent that the stroke control shaft 26 will be rotated upon actuation of thedrive shaft 28.

The stroke control shaft 26 textendsabove the top 2! of the base of the machine and has the lower part 04 of a divided ball housing 05 fixed to its free end to rotate therewith, the upper part 96 of the ball housing being secured to the lower part by means of suitable fastenings 81. As may be observed in Figure 4, the interior of the ball housing 05 isprovided with an opening which extends therethrough and whose axis is normal to the shaft 26. This opening has outer portions which are in the form of slots 98 while its central portion is recessed to form a socket for a ball 98 having drive pins I00 extending therefrom and engaged within the slots 88. Also projecting from ball 00 is a drive stud i0l which extends through an opening I02 provided in the upper member 96 *of the ball housing and for some distance above the same.

The height of the slots 98 is considerably greater than the diameter pf the drive pins I00 v with the housing 95 and the shaft 26.

while the width of the slots is substantially equal to that of the drive pins. Through this expedient the ball 99 and its stud IOI are caused to rotate At the same time this construction permits adjustment of the ball 99 within its recess whereby the drive stud IOI may be moved into a position'out of alignment with the longitudinal axis of the shaft 26. Obviously the angular movement of the drive stud with respect to the shaft 26 is limited only by the size of the opening I02 and the height of the slots 98.

The drive stud IOI serves as a crank, the throw or eccentricity of which is adjustable at will. For the purpose of holding the drive stud in adjusted positions, a passageway is formedto extend through the drive stud IM and the ball 99. One end of this passageway is threaded to receive a clamp screw I03 provided with a suitable operating knob I04. The opposite or ball end of this passageway is enlarged as shown in Figure 4 to receive a slidable pressure plug I05 adapted to be pressed against the bottom of the recess in the ball housing 95 to hold the ball and the drive stud in adjusted position. As

may be noted, the head of the plug I05 is a spherical surface of the same radius as the ball 99 so as to permit suitable contact with the socket in the lower housing 94. v v

Slidable within the passageway in'the drive stud and ball is a pressure pin I06 which is 10- rated between the end of the clamp screw I03 and the pressure plug I05. As the ball is retained within its socket by reason of the connection of the upper housing 96 to the lower housing v94, it will be apparent that sufficient movement of the clamp screw I03 towards the ball 99 will force the pressure pin I06 against the pressure plug I05 to cause the latter to firmly hold the drive stud in an adjusted position.

The construction for coupling the drive stud to the support shaft makes use of a sleeve or eccentric strap I01 loosely supported on a shoulder I08 formed on the drive stud and held thereon by the collar I09 fixed to the stud by the set screw or other fastening IIl A connection link III having av yoke II2 pivoted to the eccentric strap I01 by pivot screws III is coupled to a reciprocating drive arm II4 which in turn is secured to the support shaft SI. Another yoke H is formed on the other end of the connection link III at a right angle to the yoke H2.

The face of yoke II5 adjacent the drive stud is provided with a. recess which supports a resilient connection plug IIB adapted to extend within the yoke. A second resilient connection plug II'I, aligned with the plug H6, is slidably carried in a passageway in the connection link III which opens into the yoke and extends through the link to its outer end. Plugs H6 and II! pivotally connect the link III to a ball H8 formed on a connection member suitably secured to the end of the reciprocating arm -I I4 by suitable fastening means II9. By means of the pressure screw I20 engaged in the threaded end of the support guideway for the resilient connection plug III, the plugs H6 and III and ball I I8 are pivotally connected to each other. A lock nut I2I is 'used with the screw I20 to lock the same in engaged position. It is to be noted that the center of the ball II 0 lies in the axis of the pivot screws 44 about which the support member 43 and support shaft 5I are adapted to pivot.

As may be noted, the reciprocating drive arm I I4 bends upwardly from the ball connection I I8 and has its end opposite thereto provided with a connection collar I22iwhich loosely engages thepp rt shaft 5| and-is securedttheretoby the. set screw I23 (Figure-l) or 1 othen'suitable fasten-s. ing means. This connectioni'c'ompletesthe "drive means for reciprocating the pressurehead'4Land its work engaging n'ieansl H Hand, surfacingmachineswhe'rein a lens is reciprocatcd by handover a rotating lapp'ossess' certain advantages which it isde'sirable to simu-:

late. For example,'inhand'surfacingy the lens" 5 is readily located on any-portion ofth'e lap and is easily changed to other positions; Also the amount'of movement impartedto a lens over a lap is determined by the leng-th 'of the hand stroke of the operator; which'strokeis of course.

variable at the wilhof the operator.. In addition, hand surfacing ai'nachine of the type just described is accompanied .by reciprocation of the lens along substantially continuously changing paths which are -very rarely repeated; I

At the same time-hand surfacing requires a separate operator forealch machine so'that it is im possible for one person to operate a number'of machines. i

That our machine is capable ofcloselyretaining the advantages of a hand surfacer while overcoming its limitation will be apparent from lowered. 3

Location of the pin 64' on either. side of th longitudinal axis of the machine'is readily efiected by tilting the polishing'head 4i aboutits pivots 44 through the mechanism driven: by the handwheel 49 and also by the arcuate adjustment of the polishing head about the support shaft 5| as a center, thepolishing head being held in adjusted position on the shaftil by locking the head support member 53 to the shaft through the'clamp 51. Byadjusting the arm 6|, the resilient pin-maybe angled with respect to its lap and also may-be positioned forwardly or rearwardly of a transverse axis of the machine which passes through the work spindle 24 while obviously the vertical position of r the pin will be controlled by its locking location with respect to the clamp 63. It will be apparent that the foregoing adjustments permit a lens to be located wherever desired upon its lap, which position may be shifted whenever necessary by suitable readjustment of pin 04; 1

The polishing headis'now lowered until the resilient pin engages the-lens block after which the full stroke of the crank 13 is completed to lock the head in operating 'position'and to en gage the resilient pin in pressurecontact with the lens block. This pressure is easily'decreased or increased by operation of the hand wheelSI. Operation of the hand wheel I04'to set thethrow of the drive stud IOI may now 'be made. The amount of the stroke or the'movement of the polishing head needed for surfacing will be dependent upon the particular lens being surfaced and is readily understood by the art. Quite obviously the stroke of the polishing head may be changed iromits initial setting to some other adjustment at any time that the machine is at rest. a n r r 44 in line with the center of the lap 31.

A suitable abrasive is placed upon the lap and the switch handle 35 is turned to cause actuation of the drive shaft 28 and rotation of the work spindle and lap and reciprocation of the polishing head and its Work engaging means. It is apparent that when'the axis of the drive stud I! is moved out of alignment with the axis of the shaft 26 that the drive stud functions as an eccentric or crank which will reciprocate the link HI and arm H4 so as to cause reciprocation of the polishing head of the machine.

The reciprocating stroke or movement of the polishing head will vary from zero when the drive stud lDl and shaft 26 are aligned to a minimum for the maximum angular setting of the drive stud with respect to the shaft 26. It will be apparent that by reason of the adjustable ball connection of the drive stud ID! to the shaft 26 that the throw of the drive stud is susceptible to minute or large variations over a relatively wide range. These means permit a stroke variation for the work engaging means which is comparable with that-obtained in a hand surfacing quickly made without disturbing the work or any of the other adjustable parts of the machine.

The friction existing between the lens and the rotated lap will cause the former to be rotated. At the same time the lens and lens block are reciprocated over the lap at a frequency which differs from the rotational frequency of the lap. As will be well understood the combination of these movements will cause the lens to be reciprocated'over the lap so that it will follow the same path of movement only at infrequent intervals.

An important feature of our machine resides in the construction which locates the pivot axis For this reason tilting of the polishing head on this axis not only permits the resilient pin 64 to be located on either side of the lap but will also allow the lens to be reciprocated over the lap in a manner to compensate for the curvature of the latter. The tilting of the polishing head is especially designed to maintain movement of the lens along paths which are approximately tangential to the lap surface. Obviously the angle of tilt required for the polishing head will in-- crease with the radius of curvature of the lens being surfaced.

.Where it is found necessary, any of the adjustinents noted may be easily remade in the manner described upon stopping the actuation of the machine. Frequently, as previously mentioned, it is desirable to remove a lens from the lap for inspection. This is carried out by stopping thedevice and swinging the crank I3 for the full extent of it raising stroketo raise the polishing head to the position shown in Figure 2 where it is automatically, locked against accidental lowering movement. After the lens block has been replaced on the lap. the crank .l3 may be turned in the proper direction to again lower'the polishing head into operating position and the surfacing operation may be resumed, it being noted that the pressure adjustnientduring the raising and relowering of the polishing headhas remained at a constant setwe have provided a lens surfacing machine of simple design and rugged construction which is susceptible of facile operation. At the same time in attaining our inventive aims, we have devised a novel machine which simulates hand surfacing procedure but greatly accelerates surfacing operations while maintaining a fine control ove them.

We claim:

1. A lens surfacing machine having a base, a

drive shaft journaleo therein, a Work spindle and an intermediate shaft also journaled therein and driven from said driveshaft, a stroke control shaft journaled in the base and driven from said intermediate shaft, a rotatable support shaft carried on said base, a polishing head secured to said support shaft, work engaging means carried by said head and means for reciprocating said head on actuation of said drive shaft comprising a housing fixed to said control shaft, a ball having a drive stud thereon, said ball adjustably mounted within said housing to permit positioning of the stud eccentric of said stroke control shaft and link members drivingly connecting said stud and said polishing head support shaft.

2. In a lens surfacing machine the combination of a base, a rotatable work spindle in said base, a polishing head secured to a rotatable shaft carried on said base, drive means for said spindle and means for reciprocating said head, said reciprocating means comprising a stroke control shaft rotatably mounted in said base and actuated from said drive means, a housing secured to said control shaft, said housing provided with a socket, a ball adjustable in said socket, a drive stud on said ball, pins on said ball engaged by said housing, pressure means for-holding said ball in adjusted positions and link members operatively connecting said stud to said polishing head.

3. In a lens surfacing, machine the combination of a base, a rotatable work spindle therein, a polishing head secured .to a rotatable support shaft carried by said base, drive means for said spindle and means for reciprocating said head comprising a rotatable stroke control shaft mounted in said base and actuated from said drive means, a housing secured to an end of said stroke control shaft, said housing provided with a socket, a ball retainable and movable in said socket, a drive stud projecting from said ball and beyond said housing, pins on said ball engaged by said housing, said stud and ball provided with an opening extending entirely therethrough, a clamping plug engageable with said housing mounted in the end of said bore adjacent the surface of said ball, a pressure pin slidable in said bore and contacting said plug, a threaded portion at the other end of said bore, a clamp screw engaging said threaded portion and contacting said pressure pin, and link members operatively connecting said stud to said polishing head support shaft.

4. A lens surfacing machine comprising a base, a work spindle journaled therein, a support shaft rotatably mounted upon said base, a polishing head secured to said support shaft, work engaging means carried by said head, drive means for said spindle and means for reciprocating said head, said reciprocating means having a stroke control shaft journaled in said base and rotated from said drive means, a housing fixed to said stroke control shaft, a ball having a drive stud projecting therefrom, said ball adjustably mounted within said housing to permit positioning of said stud eccentric of said stroke control shaft, pins on said ball engaged by said housing, a link member in the form of an arm having a yoke at each end thereof, a second link member having one end fixedly engaged to said support shaft and its other end engaged in one of said yokes, said stud extending through the other yoke and pivotally connected thereto.

5. A lens surfacing machine having a base, a drive shaft journaled therein, a work spindle and an intermediate shaft also journaled therein and driven from said drive shaft, a stroke control shaft journaled in said base and driven from said intermediate shaft, a support shaft rotatably mounted above said base and angularly adjustable in a vertical plane located transversely of said base, a polishing head secured to the support shaft, work engaging means carried by said head, gear means for angularly positioning said support shaft, and means for reciprocating said head on actuation of said drive shaft comprising a housing fixed to said control shaft, a ball having a drive stud thereon, said ball adjustably mounted within said housing to permit the longitudinal axis of said stud to be positioned out of alignment with the longitudinal .axis of said stroke control shaft and link members operatively connecting said stud to said head support shaft.

6. A lens surfacing machine having a base, a drive shaft journaled therein, a work spindle and an intermediate shaft also journaled therein and driven from said drive shaft, a stroke control shaft journaled in said base and driven from said intermediate shaft, a support shaft rotatably mounted above said base and angularly adjustable in a vertical plane located transversely of said base, a polishing head loosely mounted on said support shaft, locking means for securing said head to its support shaft to rotate therewith, an extensible arm carried by said head, work engaging means carried by said arm, gear means for angularly 4 positioning said support shaft, and means for reciprocating said head on actuation of said drive shaft comprising a housing fixed to said control shaft, a ball having a drive stud thereon, said ball adjustably mounted within said housing to permit the longitudinal axis of said stud to be positioned out of alignment with the longitudinal axis of said stroke control shaft and link members operatively connecting said stud to said head support shaft.

'7. In a lens surfacing machine the combination of a base, a work spindle rotatably mounted in the base, a pair of standards extending above the base, a shaft support member pivotally mounted between said standards for tiltingmovement about a horizontal axis located longttudinally of said base, gear means on said support member cooperating with gear means on said base for tilting said support member, a support shaft rotatably mounted within said support member, a polishing head secured to said support shaft, work engaging means carried by said head, drive means for said spindle and means for reciprocating said head, said reciprocating means comprising a stroke control shaft rotatably mounted in said base and actuated from said drive means, a housing secured to said control shaft, said housing provided with a socket, a ball adjustable in said socket, a drive stud on said ball, pressure means for holding said ball in adjusted positions, pins on said ball engaged by said housing, and link members operatively connecting said stud to said polishing head.

8. In a lens surfacing machine of the type having a polishing head adapted to be reciprocated over a lap, said polishing head being pivoted for movement into operative and inoperative positions, means for moving said head into said positions comprising a shaft rotatably carried by said head, an eccentric on said shaft, gear means for rotating said shaft, a link pivoted to said eccentric, anarm pivoted to said link, said arm provided with a slot, a pin fixed to said head and engaged with said slot, said eccentric located out of alignment with the pivot center of said arm and the center of said pin when the polishing head is in operative and in inoperative positions.

9. In a lens surfacing machine of the type having a polishing head pivotally mounted and adapted to be raised and lowered into operative and inoperative positions with respect to a lap mounted on said machine and to be reciprocated ever the lap to cause work engaging means carried thereby to reciprocate a lens block and lens over said lap during the actuation of the machine, means for moving said head into said positions comprising a shaft rotatably carried by the head, gear means for rotating said shaft, an eccentric on said shaft, a link having one end thereof pivoted to said eccentric, an arm having one of its ends pivoted to the other end of said link, the end of the arm opposite said pivot provided with a slot, a pin on said head engaged with said slot, the axis of said eccentric located in offset relation to a plane passing through the axis of said pin and the axis of the pivot for said link and arm when said head is in raised and lowered positions and stop means carried by said link for limiting the movement of said head about its pivot.

10. In a lens surfacing machine having a head support member and a polishing head pivoted thereto and adapted to be moved into operative and inoperative positions with respect to a lap on said machine and to be reciprocated over the lap during actuation of the machine to cause work engaging means carried thereby to reciprocate a lens block and lens over said lap, the combination of means for moving said head into said positions and means for exerting a grindingpressure on a lens on the lap comprising a shaft rotatably carried by said head, gear means for rotating the shaft, an eccentric on said shaft, a link pivoted on said eccentric, an arm pivoted to said link, said arm having a slot, a pin fixed to said head and engaged with said slot, a lever pivoted to said head support and also to said link about the pivot axis of said arm, a pressure pin in said head, a second arm pivoted to said head and held against said pressure pin by tension developed by a spring connected thereto and to said lever, and stop means on said link contactable with said head support to limit the movement of said head. the axis of said eccentric offset with respect to a plane through the axes of said slot engaged pin and the pivot for said link and first mentioned arm when said head is in said positions.

lap on the spindle, a rotatable shaft on said base,

a polishing head support secured to said shaft, a polishing head, work engaging means carried by said head for contact with a lens block and lens on said lap, said head pivoted to said head support, rotatable crank means for reciprocating said head, drive means for said spindle and said crank means, adjustable means for varying the by said arm. said lever also pivoted to said head 10 support, adjustable spring tension means connecting said lever to said head, and stop means on said link contactable with said head support, the axis of said eccentric located in offset relation to a plane through the axes of said pin and the pivot for said link and arm when said head is in 0per ative and inoperative position.

JOSEPH J. MCCABE. GEORGE C. SCHELLING.

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