US2175719A

US2175719A - Lens edging machine

Info

Publication number: US2175719A
Application number: US167008A
Authority: US
Inventors: Long Eli Maynard
Original assignee: SHURON OPTICAL CO Inc
Current assignee: SHURON OPTICAL CO Inc; SHURON OPTICAL COMPANY Inc
Priority date: 1937-10-02
Filing date: 1937-10-02
Publication date: 1939-10-10
Anticipated expiration: 1956-10-10

Description

ocr, 1o, 1939. E M, LONG 2,175,719

LENS EDGING MACHINE Filed Oct. 2, 1937 4 Sheets-Sheet l /pg, lla fa? mj/7 lf3/10 o 2/ /oo/o/ l/l Z3..

I *i l f Il 1 A /z/ /7 ./l @Il me" /63 ,2 J| G1 a Y Y 2 /74 4 Ma 1 22 .5a 7 l I J l 4 /8/ /fa u1 'BYI T DRNEY' oct. 110, 1939.

E. M. LQNG LENS EDGING MACHINE 4 Sheets-Sheet 2 Filed Oct. 2, 1937 Oct. 10, 1939. E M LONG 2,175,719

LENS EDGING MACHINE Filed oct. 2, 1957 I 4 sheets-sheet :s

'TT DRNEY Oct. l0, 1939. E. M. LONG LENS EDGING MACHINE Filed Oct. 2, 1937 4 Sheets-Sheet 4 IHVENT DR Patented Oct. 10, 1939 UNITED STATES c PATENT OFFICE LENS EDGING MACHINE Application October 2,

15 Claims.

This invention relates to improvements in a lens edging machine in which a lens holding means operates in conjunction with a rotating abrasive stone or wheel.

An object of the invention is to provide a ma.- chine having a rotating abrasive wheel for grinding the edge of a lens, with a simply constructed and controlled lens holder adapted to be oscillated about an axis arranged in a plane extending substantially normal to the axis of rotation of the wheel, whereby the angular position of the lens with respect to the grinding surface of the abrasive wheel will be constantly changing as the lens is moved back and forth across said grinding surface from one side thereof to the other.

Another object of the invention is to provide simple control means adapted to be manually operated for altering the path of travel of the lens holder during the oscillation thereof, whereby lenses of various cross-sectional contours or curvatures may be properly positioned with respect to the grinding surface of the abrasive wheel to obtain maximum and uniform travel of all lenses transversely oi the abrasive wheel.

A further object of the invention is to provide an improved lens holder for a lens edging machine whereby the lens may be quickly and accurately mounted therein and without the necessity of utilizing a portable lens chucking or centering device which is usual when positioning lenses in lens edging machines as heretofore constructed.

A still further object of the invention resides in providing a grinding machine of the above mentioned class with a lens holder having a limited movement toward and from the abrasive wheel and to provide means for adjusting the abrasive wheel toward the work'holder to com pensate for Wear of the wheel during use.

An additional object of the invention is to provide a lens edging machine with a signaling device so constructed and controlled that the operator may readily determine from a position atf a distance from the machine, when the grinding of the edge of each lens is completed.

A still further object of the invention is to provide a lens edging machine with an improved truing device for the abrasive wheel.

Other objects and advantages pertaining to the construction of the device and to the form and relation of parts thereof will more readily appear from the following description taken in connection with the accompanying drawings, in which:

1937, Serial No. 167,008

Figure 1 is a top plan view of a lens edging machine embodying the various features of this invention.

Figure 2 is an enlarged vertical sectional view taken substantially in the plane of the line 2 2, 5 Figure l, and illustrating a portion of a Water receptacle associated therewith and portions of the stone or abrasive wheel and base broken away.

Figure 3 is a horizontal sectional View taken substantially in the plane of the line 3 3, Figure 2.

Figure 4 is an enlarged detail vertical sectional view through the upper portion of the machine and taken substantially on line 4 4, Figure 1.

Figure 5 is a detailed horizontal sectional view taken on line 5 5, Figure 2.

Figure 6 is a detail sectional view taken on line 6 6, Figure 5.

Figure 7 is a detail vertical sectional view taken on line 1 1, Figure 5.

Figure 8 is a perspective view of a lens clamp suitable for securing a lens to one of the clamping heads of the lens holder illustrated in Figures 1, 2 and 5.

Figures 9 and 10 are detail vertical sectional views taken respectively on lines 9 9 and |0 l0, Figure 5.

Figures 11, l2 and 13 are detail sectional views taken respectively on lines Il ll, l2 l2 and 3|3, Figure 10. 30

Figure 14 is an enlarged detail sectional view taken substantially on line M H, Figure 4.

Figure 15 is a detail vertical sectional view taken substantially in the lplane of the line I5 I5, Figure 1.

Figure 16 is a diagrammatic view illustrating the action of the lens during the oscillation thereof across the grinding surface of the abrasive wheel.

As illustrated in the drawings, the machine comprises a supporting base or frame l composed of two sections, a lower section 2 and an upper section 3, which are fxedly secured together by any suitable means as screws 4. The abrasive wheel 5 is rmly clamped to opposed collars 6 and 1 which are xedly secured to a shaft 8 to \rotate therewith. The shaft 8 extends at its ends beyond the adjacent collars 6 and 'l and is journaled in suitable bearings 9 connected with a cradle or rock frame I0 which is provided with a central opening Il for receiving the wheel 5 therein. This frame or cradle I0 is a substantially rectangular member adapted to be readily received within the chamber 2' of the lower base section 2, while the bearing members 9 are sev spective spindles.

cured to said frame or cradle intermediate the ends thereof so that the shaft 8 extends transversely of the frame in a substantially horizontal plane.

The rear end of the cradle I8 is pivotally connected by a horizontally disposed shaft I2 to the upper section 3 of the base I in a plane above and at the rear of the center of the base I, as shown in Figures 2 and 3. 'I'he cradle I8 is adapted to extend forwardly and downwardly from the shaft I2 to a position within the lower section 2 of the base I adjacent the forward end thereof. Rotatably mounted in the forward end of the cradle I is a pin I3 which is arranged in substantially parallel relation with the shaft I2 and has one end thereof extending outwardly beyond the adjacent side of the frame or cradle I0, as shown in Figure 3.

An adjusting screw or bolt I4 is mounted in screw-threaded engagement with the outer end of the pin i 3 and extends upwardly therefrom through a suitable opening provided in an offset portion 3' of the upper base section 3, as shown in Figures 1 and 2. This bolt I4 is utilized for adjusting the forward end of the frame or cradle I0 and thereby elevate the wheel 5, as the same wears away in use, for maintaining the peripheral surface of the wheel in cooperative relation with a lens holder I6 mounted on the upper section 3 of the main supporting base or frame I in a plane above the wheel 5.

The lens holder, in this instance, comprises opposed, coaxial clamping heads I1 and I1 mounted end to end upon coaxial rotary shafts or spindles I8 and I8' which, in turn, are journaled in suitable bearings I9 and I 9 provided in the outer or free portion of a vertical swinging frame or carriage 2II pivoted at 2| to the forward portion of a horizontally swinging frame 22. 'I'he frame 22 has the rear portion thereof pivotally connected by a pair of axially spaced pivotal members or hinge

pins

23 and 23 to the rear portion of the upper section 3 of the base the axes of the pivotal pins 23 and 23' being arranged in a plane extending substantially normal to the axis of rotation of the wheel and spindles |8 and I8'.

'Ihe adjacent ends of the lens clamping heads I 1 and I1 are provided with the usual pads 25 composed of rubber, leather or the like for frictionally engaging the opposite faces of the lens to cause the latter to rotate with the collars and also to reduce the liability of breakage of the lenses or marring the lenses when clamping them between the heads. The heads I1 and I1' may be of any desired shape or outer configuration, depending upon the shape of the lens to be ground, and are preferably removably connected with their re- One of the heads, as I1, has the face thereof adjacent the head I1' provided with diametrically disposed guide lines 26 and 26', cut or stamped thereon, arranged to extend across the head in right angular relation to each other for assisting in correctly positioning the lens thereon in a manner which will hereinafter be more fully explained.

The bearing members I9 for the shaft or spindle I8 are mounted in axially spaced relation in a bearing supporting member or head 28 which, in this instance, is T-shaped in cross section, as shown in Figure 5, with the bearings mounted at opposite ends of the transverse portion 28' thereof. The laterally extending portion 29 of the bearing support is a tubular member which is rotatably mounted in a suitable opening extending inwardly from the forward side of the carriage adjacent one end thereof. This bearing support 28 is maintained in operative relation with the carriage 20, by a screw member 30 which extends through an elongated slot 3| formed in the carriage 2I| and is screw-threaded into the adjacent portion of the member 29, as shown in Figures 5 and '7. The axis of the bearing support portion 29 is arranged at substantially right angles to the axis of the spindle I 8 so that by rotating the bearing member 28 about the axis of the portion 29 thereof, the head I1, connected with the spindle I8, may be moved from the position in coaxial alignment with the head I1 to a position at one side thereof, as indicated by broken lines in Figure 7. The length of the slot 3| is such that this rotary movement of the bearing support 28 is substantially equal to 90, whereby the head I1 may be moved from a horizontal position in cooperative relation with the head I1' to a vertical position above the member 28, with the clamping surface of the head containing the

guide lines

26 and 26 uppermost in position to be readily seen by the operator.

The bearing support 28 is releasably locked in either of said horizontal or vertical positions by a spring actuated lock pin 32, which is slidabiy mounted in the carriage 28 for axial movement into and out of engagement with either one of a pair of apertures 33 formed in the bearing portion 29 of the bearing support 28 in right angular relation with each other, as indicated in Figure 7. The lock pin 32 extends from the bearing member 29 toward the opposite end of the carriage 20 in substantially parallel relation with the spindles I8 and I8 and has the end thereof adjacent the spindle I8' provided with a diametrically disposed slot 32' which receive therein the free end of an arm 35. The arm 35 is secured at the other end to a vertically disposed shaft or stud 36 rotatably mounted in the carriage 20 intermediate the pin 32 and spindle I8'.

A second arm 31 is secured tothe stud 36 to extend outwardly therefrom in substantially right angular relation to the arm 35 and has the free end thereof adapted to be engaged by a pin 38 secured to an enlarged, cylindrical portion 39 of a control shaft 40, which is journaled in the carriage 20 at one side of and in parallel relation to the stud 36. The pin 38 is mounted in eccentric relation with the control shaft 40 so that, as said shaft is rotated in one direction, the pin 38 will produce a corresponding rotation of the arm 31, stud 36 and arm 35 for moving the lock pin 32 out of one of the apertures 33.

As shown in Figure '7, the enlarged portion 39 of the control shaft 48 is journaled in the upper portion of the carriage 20, while the lower portion 4I of the shaft is of considerably less diameter than the portion 39 and is journaled in the lower portion of the carriage 20 in coaxial relation with the portion 39. The rotation of the control shaft 40 in one direction is limited by a pair of stop pins 43 and 43', one of which is secured to the shaft portion 39 adjacent the outer face of the carriage 2U, as shown in Figure 7, while the other pin is secured to the carriage 20 as indicated in Figure 1. The arrangement of the pins 43 and 43' is such that the pins 38 will4 Vgear'84 secured to thelspindle *I8 adjacent the nected with the carriage 20 at the rear of the control shaft 48. The arm 46 extends forwardly from the pin 41 and has the forward end thereofv bifurcated and operably connected to the spindle I8' by a grcoved collar 48 fixedly secured to said spindle, .so that as the arm is rocked about the axis of t-he stud 41 by the eccentric 44, the spindle I8 will be moved axially in one direction or the other for bringing the head I1 connected therewith into and out of cooperative relation with the head I1 for releasably clamping a lens between said heads.

The relation of the pin 38, arm 35, eccentric 44 and arm 48 is such that when the control shaft 40 is moved in a direction for separating the heads I1 and l1', the pin 38 will not-engage the arm 35 until the head l1' has approached nearly the limit of its outward movement so that the lock pin 32 will remain in holding engagement with the bearing support 28 upon the normal movement of the head l1' into and out of holding engagement with a lens positioned between head I1' and the head I1. It, therefore, follows that a lens clamped between the heads l1 and I1 may be released therefrom during normal axial movement of the spindle I8', and when it is desired to release the bearing support 28, this may be accomplished by a slight additional rotary lmovement of the control shaft 40 in a direction to produce further outward movement of the spindle I8', whereupon the pin 32 will be moved axially out of holding engagement with the bearing portion 29 by the engagement of the pin 38 with the arm 35. This rotation of the control shaft 40 for actuating the lock pin 32, which is in an anti-clockwise direction in this instance, is limited by the stop pins 43 and 43' as the lock pin is disengaged from the member 29. The rotation of the control shaft 40 maybe readily accomplished by means of a hand wheel 50 secured to the upper end of the shaft.

In order that the spindle I8 and the head l1 carried thereby may be accurately aligned with the spindle I8 and head l1 when in the horizontal position, I have provided a stop screw 5I which is screw-threaded in the carriage 2D in alignment with the upper end portion of the slot 3l to engage the outer end or head portion of the screw 30 as said screw approaches the limit of its upward swinging movement, as illustrated in Figure '1.

The spindles I8 and I8 are rotated in unison and, for this purpose, each of these spindles is operatively connected with a shaft 55, common thereto, in the following manner:

The shaft 55 extends longitudinally through the carriage 20 adjacent the rear portion thereof with the end portions of the shaft rotatably suplported in corresponding end portions of the carriage. That is, the left-hand end portion of the shaft 55 is journaled in a bearing member 56 mounted in the carriage 28, while the opposite'or right-hand portion of the shaft is rotatably mounted in an elongated hub 51 provided on a gear 58, said hub being rotatably mounted in the carriage 28, as shown in Figure 5. The shaft 55 is operatively connected with the spindle I8 by means of a pair of spiral gears 59 and 60, one of which is secured to the shaft 55 and the other gear 88 is secured to a short shaft 8| which is journaled in a bearing member 82 mounted in the portion 29 of the bearing support 28 in coaxial relation therewith. The forward end of the shaft 8l has secured thereto a bevel gear 83 which is in meshing engagement with a bevel inner bearing member I9.

The shaft 55 is connected with the spindle I8' by means. of an idle gear 88 rotatably connected with the carriage 2 in meshing en agcment with the gear 58. This idle gear 86 is also in meshing engagement with a spur gear 81 secured to the spindle I8 adjacent the outer end of the collar 48. The face of the gear 61 is of considerably greater width` than that of the idle gear 66 so as to remain in constant meshing relation with the idle gear during the axial movement of the spindle i8' for bringing the head I1 into and out of cooperative relation with the head I1 and also during the operation of the lock pin 32 to bring the same out of holding engagement with the bearing support 28.

The shaft 55, in this instance, is rotated from the abrasive wheel shaft 8 and, for this purpose, the shaft 8 is provided with a worm 1ll secured to one end thereof which is extended beyond the adjacent bearing member 9, as shown in Figures 3 and 4. The worm 10 is in meshing engagement with a worm gear 1I mounted on a stub shaft 12 which is journaled in a gear housing 13 connected with the adjacent side of the frame or cradle I0. The shaft 12 extends in substantially right angular relation to the shaft 8 and has secured thereto a Worm 14 which meshes with a worm gear 15 secured to the lower end of a shaft 18 also journaled in the gear housing 13. This shaft 18 extends outwardly beyond the upper wall of the housing 13 and has the upper end thereof provided with an enlarged tubular portion 11 which, in turn, is provided with a pair of diametrically disposed slots 18 extending inwardly from the upper or outer end thereof. Connected with the tubular portion 11 ofshaft 16 to be driven by said shaft is. an extension shaft 19 having a head 8| connected to the lower end thereof and which is slidably mounted within the tubular member 11. To the head 8l is secured a pin 82 which extends outwardly at both ends beyond the adjacent portion of the head into the slots 18, as shown in Figure 4. The

other end of the shaft 19 is connected by a suitable universal joint structure 83 with a stub shaft 84 journaled in the lower portion of the carriage 20 beneath the shaft 55. To the upper end of the shaft 84 is secured a bevel gear 85 which isA` in meshing engagement with a correspondinggear 86 rotatably mounted upon the shaft 55 adjacent the gear 58 (see Figure 5).

The gear 86 is releasably connected with the shaft 55 by a clutch mechanism which, in this instance, comprises a finger knob 88 slidably mounted upon the outer end of the shaft 55 which extends beyond the adjacent portion of the carriage for receiving said knob. The knob 88 is secured to the shaft 55, to rotate therewith, by means of a screw 89 connected with the knob and which projects into an elongated recess 90 provided in the peripheral surface of the shaft 55.

Secured to the inner end portion of the nger knob 88 is a plurality of clutch pins 9i arranged in circumferential spaced relation to each other about the shaft 55. These pins 9|, two of whichare shown in Figure 5, extend inwardly fromzthe knob 88 through corresponding apertures formed parent that when the nger knob is in its innermost position, the clutch pins 9| will operatively cdnnect the gear to the gear 58 and knob 88 for transmitting motion to said gear 58 and knob 88 and thence to the shaft 55 through the screw I9.

It will now be observed that when the knob 88 is in its innermost position, rotation of the shaft 8 will produce a corresponding rotation of the shaft 55 and, when the knob 88 is in its outermost position, as determined by the coaction of the screw 89 and recess 90, shaft 55 will be disconnected from operative relation with the shaft 8 and may be manually rotated by manipulation of the knob 88, whereby the spindles I8 and I8 may be manually rotated when necessary.

The shaft 8 and abrasive wheel 5 may be rotated from any suitable source of power through the medium of a belt, not shown, and a pulley 93 secured to the collar 'I as illustrated in Figure 3.

In order that the spindles I8 and I8' will operate smoothly and with a maximum amount of efficiency when a lens is clamped between the heads |1 and I1', one of the spindles, as I8, may, as shown in Figures 5 and 9, have secured thereto a brake drum or collar 95 positioned between the gear 64 and the outer bearing member I9. This drum 95 is engaged by a spring pressed plunger 96 slidably mounted in a tubular case 91 secured to the supporting member 28 to extend outwardly therefrom substantially radially from the axis of the spindle I9. A screw 98 may, as shown, bevscrew-threaded in the outer end of the case 91, whereby the pressure of the 4pin 96 upon the drum 95 may be controlled. The

-frictional engagement of pin 96 with drum 95 produces suilicient drag upon spindles I8 and I8' that backlash occurring in the gear members connecting said spindles with the shaft 55 and also the drive mechanism connecting shaft 55 with shaft 8 will not produce vibration of said spindles.

As illustrated more clearly in Figures 5 and l5, the pivotal pins 2| for connecting the carriage 20 with the frame 22 are arranged a short distance below the shaft 55 and provide the carriage 20 with a limited swinging movement sufflclent to operably maintain the lens carried by the heads and |1' in grinding engagement with the peripheral surface of the abrasive wheel or stone 5. In order that the swinging movement of the housingr 20 may be manually controlled, I have provided the housing with a suitable lever |00 connected with the rear portion adjacent the left-hand end thereof, as shown in Figures 1 and 15.

The lever |00 is provided with a laterally disposed arm or extension |0| which projects rearwardly and downwardly therefrom, as shown in Figure 15, and has pivotally connected thereto, as at |02, a latch member |03. This latch mem ber extends rearwardly some distance from the pivot |02 and has the rear portion thereof provided with an elongated slot |04 which slidably receives therein a pin |05 secured to the frame 22. The length of the slot |04, of course, determines the amount of swinging movement of the carriage 20 about pins 2|, and the upper end of the slot is provided with a laterally disposed portion |04' adapted to receive pin |05 therein. The outer lower side of slot portion |04' provides a shoulder |06 adapted to engage the pin |05 for releasably maintaining the carriage in the uppermost position.

forms a fingerpiece |03 whereby the operator, when grasping the lever |00, may readily effect the upward movement of the rear end portion of the latch member to bring the pin |05 out of engagement with the shoulder |06 and into the major portion of the slot |04, and thus release the carriage and permit the same to rock downwardly about the pivots 2| to bring the lens carried by the heads and nto pressure engagement with the peripheral surface of the wheel 5.

The pressure engagement of the lens with the wheel 5 may be readily controlled, in this instance, by a weight |08 which is slidably mounted upon a bar |09 secured to the outer ends of side portions ||0 of a U-shaped bracket which is positioned exteriorly of the base adjacent the left-hand side thereof. Bracket is securely fastened intermediate its ends to one end of a stub shaft ||2 which is journaled in said side of the base section a short distance in front of the shaft 8. The shaft ||2 extends into the interior of the case section 2 and has secured to the inner end thereof one end of an arm ||3 which extends rearwardly from the shaft beneath n the adjacent bearing member 9 and has the outer end thereof connected with the outer end of the arm |0| by a link H4.

The weight |08 is clamped to the bar |09 by means of a thumb screw ||5 so that the weight during the grinding operation. This movement A of the lens is produced by oscillation of the frame 22 about

pivotal pins

23 and 23. In order that this oscillatory movement of the frame 22 may be produced by power means, I have provided the shaft I6 with an eccentric cam (sec Figures 4 and 14) arranged thereon adjacent the upper face of the gear housing 13 between said housing and the tubular member A pitman ||8 is journaled at one end upon the eccentric cam and extends rearwardly therefrom and has the other end thereof pivotally connected by means of a spring-pressed plunger ||9 and a take-up screw |20 mounted in the rear' end of the pitman to a control shaft |2| journaled in the frame 22 at one side of the axis of rotation thereof. As shown in Figures 1 and 4, shaft |2| has the lower end thereof reduced in diameter and provided with a spherical portion |2| which is arranged in eccentric relation with the shaft and is clamped between the screw |20 and plunger ||9, said screw and plunger being provided with concave recesses in their adjacent ends for receiving the spherical portion |2I therein.

In order to positively maintain the pitman in engagement with the lower end of the control shaft |,2|, I have provided an adjustable rest, in the form of a screw |22, mounted in a lateral projection |23, formed on the frame 22 beneath the shaft |2I, said screw |22 being arranged sub- The upper end of the screw |22 slidably contacts the pitman ||0 so that the pitman may readily move relative thereto during the rotation of the shaft IZI.

In grinding lenses of different curvatures, it often becomes necessary to shift the path of movement of the heads I1 and 11' with respect to the wheel 5 to maintain the lens in proper relation with the wheel. This shifting of the frame, as will be readily apparent, is obtained by rotating the shaft |2| to swing the frame 22 in one direction or the other about the ypivotal pins 23 and 23' and with respect to the pitman H8, whereby the center of oscillation of the clamping heads will be in the plane or at one side of the center line of the peripheral surface of the abrasive wheel to maintain the center of oscillation of that portion of the lens edge contacting the wheel substantially midway between the sides of said o wheel.

The throw of the eccentric cam ||1 and the spacing of the control shaft |2| with respect to the axis of oscillation of the frame 22 is such that as the shaft 16 is rotated the lens carried by the heads I1 and |1' will be moved from in close proximity to one side surface of the wheel 5 to the other side surface thereof and the stroke of oscillation of the frame and, therefore, of the carriage 20, will remain uniform for all positions of member |2I'. In other words, rotation of the spherical member |2| about the axis of control shaft 2| will produce a corresponding movement of member |2| toward or from the axis of rotation of cam ||1. 'This results in a corresponding increase or decrease inthe effective length of pitman H8. When the member |2| is adjusted to produce a maximum effective length of pitman IIB, as shown in Figure 14, the center of oscillation of clamping heads I1 and I1' will be at the right-hand side of the center line of the peripheral surface of wheel 5 when viewed from the front, When the effective length of pitman ||8 is reduced to a minimum by member |2|' being moved to that side of the axis of control shaft 2| remote from cam ||1, the center of oscillation of heads |1 and I1' will be at the left-hand side of the center line of the peripheral surface of wheel 5. In either of the positions of member |2| the edge of a concavo-convex lens may be ground and when the edge of a substantially flat lens is to be ground, member |2| is adjusted to produce an intermediate effective length of pitman H8.

In order that the edge of a lens may be accurately ground to produce a lens of circular or predetermined, non-circular shape, the spindle I8 is extended a short distance outwardly beyond the outer bearing member I9 and the adjacent side of the bearing support 28, and has secured thereto a collar |28. This collar is provided with a pair of diametrically disposed dowel pins |29 which project laterally from the outer face thereof t0 extend into corresponding openings provided in a former or pattern |30 for supporting said former or pattern. The former |30 is releasably secured to the collar |28 by a pair of spring jaws |3| mounted in the outer end portion of the spindle I8 and which extend outwardly from said spindle through a central opening provided in the former |30, as shown in Figure 5.

The support |31 extends above the extension |39 and has the upper end portion thereof provided withV screw threads which are engaged by a graduated index wheel |40. This wheel |40, when in contact with the upper surface of the extension |39 has the upper surface thereof aligned with a projection or lug |42 formed 4integral with the adjacent portion of the frame 22, as shown in Figure 5. This projection |42 is provided with an index mark or line |43 adapted to register with successive graduating lines |44 formed on the upper surface of the wheel in uniform circumferential spaced relation with each other. The spacing of the graduating lines |44 is so related to the pitch of the screw-threads formed on the upper end of the support |31 that when the wheel is rotated a distance equal to the spacing of two adjacent lines |44, the bracket |35 will be raised or lowered with respect to the frame 22 a distance equal to the difference in length of the major diameter of a corresponding lens and that of the lens of the next` size.

The back-rest |33 has the upper surface thereof slightly curved outwardly and is provided with a shoe vor hardened contact plate |45 adapted to be engaged by the peripheral edge of the former |30 during the grinding of the lens. This back-rest |33 is provided with a stud |46 (see Figure 13) which extends outwardly from one side thereof in a plane over the upper edge of the bracket |35 in slightly spaced relation thereto. A screw |41 passes through the stud |46 and is screw-threaded into the adjacent portion of the bracket |35.

Surrounding the screw |41 and positioned between the stud |46 and bracket |35 is a spring |48 which yieldingly urges the stud |46 outwardly into engagement with the head of the screw which `limits the outward movement of the stud and back-rest |33. The inner movement of the back rest and stud I 46 is limited by the engagement of the stud with the adjacent edge of the bracket |35. Secured to the end of the back rest |33, opposite the pivot |34, is a pin |49 which extends downwardly therefrom and has the lower end thereof provided with a tip |50 composed of rubber or other suitable insulating material for operating an electric switch |5| connected to the bracket |35.

The switch I5| comprises a supporting block |52 composed of bre or other suitable insulating material and which is secured, in any suitable manner, to the bracket |35, as shown in Figure 10. Secured to the block |52 is a spring contact element |53 which extends beneath the tip |50 in slightly spaced relation to a second contact element |54 also secured to the block |52, said contact element |53 being adapted to be moved downwardly into engagement with the contact |54 when the back rest ismoved down- -wardly against the action of the spring |48. The

engagement of the contact |53 with contact 54 closes an electric circuit C connected with said contacts for the purpose of operating a signal S which, as diagrammatically illustrated in Figure 10. is in the form of an incandescent lamp.

In order that water may be supplied to the abrasive wheel 5 for moistening the same, I have provided a receptacle |56 mounted upon a bracket |51 secured to the frame 22, as indicated in Figure 2. The receptacle is shown provided with a control valve |58 associated with an outlet opening |59 provided in the bottom of the receptacle. A delivery tube |60, in communication with outlet opening |59, extends forwardly therefrom to a position over the wheel 5 a short distance at the rear of the clamping heads I1 and I1'.

When operating, the abrasive wheel 5 is rotated in an anti-clockwise direction, as viewed in Figure 2. In order that the dust formed in grinding and excess water carried on the peripheral surface of the stone will not be carried over the top of the stone, I have provided the upper base section 3 with a tubular case I6I in the rear portion thereof and which is arranged in the plane of the wheel 5 intermediate the bearing members 23 and 23', and extends outwardly from the base section through an opening |62 formed in the frame 22. In the case I6I is slidably mounted a tubular holder |63 which is adapted to extend through the case I6I to within a short distance of the peripheral surface of the wheel 5 and has mounted in the inner end portion thereof a sponge |64 adapted to bear against the peripheral surface of the wheel 5. The inner diameter of the holder |63 is substantially equal to or slightly greater than the width of the stone 5 so that the sponge |64 will not only collect abrasive material carried by said stone, but will also function to spread the water carried thereby across ,the peripheral surface of the stone.

In order that the abrasive wheel 5 may be maintained in the most efficient grinding condition, I have provided a novel truing device which is operatively connected with the base I to be used as occasion may require. This truing device, as shown more clearly in Figure 2, comprises a substantially rectangular hone or carborundum stick |65 which is adjustably clamped by a plate |66 and screws |61 to the head |66 of a support |69. This support |69 includes a cylindrical extension |10 which is connected with the head |68 and extends outwardly therefrom through a sleeve I1| which is screw-threaded in a suitable aperture |12 formed in the front wall of the upper base section 3.

In order that the sleeve may thus be readily turned to effect the axial adjustment thereof, I have provided the outer end portion of said sleeve with a hand .wheel |15. The sleeve |1| is secured in the adjusted position by a screw |16 mounted in the base section 3. The position of the sleeve |1| in the base section 3 is such that the hone |65 will extend in substantially radial relation to the abrasive wheel 5 with the inner end of said hone normally arranged in parallel relation with the adjacent portion of the peripheral surface of the abrasive wheel. The width of the hone I 65 is substantially equal to the width of the wheel 5. The distance the hone |65 is arranged at one side of the axis of rotation of the head |68 preferably exceeds onehalf the width of the abrasive wheel so that the hone will swing back and forth across the face of the stone in an arc having its center lying in the axis of the extension |10. It will, therefore,

be seen that instead of the inner end of the hone having a concave recess ground therein during the truing of the wheel 5, said end of the hone will be maintained substantially flat with the result that the hone will have a line contact with the peripheral surface of the wheel 5 during the truing operation. The hone will, therefore, true the abrasive wheel surface much more rapidly and' accurately than when the hone is operated, in the conventional manner, that is, toward and from the surface of the abrasive wheel in a straight line substantially normal to said surface. whereby the inner end of the hone engages the surface of the wheel throughout substantially its entire area. The head |68 may, as shown, be provided with a recess |68 extending inwardly from the end thereof adjacent the wheel 5 for the reception of a sponge |18 adapted to normally bear against the peripheral surface of the wheel for preventing water and dust collecting on the hone |65.

The operation of the device will now be understood to be substantially as follows:

The wheel 5 is maintained with the upper peripheral surface thereof in cooperative relation with the clamping heads |1 and |1' by manipulation of the bolt I4 to produce upward swinging movement of the cradle I as the peripheral surface of the wheel is worn away. After the correct former or pattern |30 for the lens to be ground has been selected, the backrest |33 is adjusted relativeto the frame 22 by the manipulation of the index wheel |40 to bring the graduation mark |44, corresponding to said former or pattern, into registration with the index line |43 on the frame 22.

The bolt I4 is next manipulated to bring that portion of the peripheral surface of the wheel adjacent the back-rest |33 into the transverse plane of substantially the central portion of the outer face of the shoe |44, so that when the former or pattern engages the shoe, a corresponding portion of the lens will be in contact with the peripheral surface of the wheel 5 and the center of the lens, which is positioned in alignment with the center of the former 30, will be spaced from the adjacent surface of the wheel 5 a distance corresponding .to the spacingI of the center of the former from the outer surface of the shoe |44. It, therefore, follows that the lens mounted between the clamping heads I1 and I1 will be ground so as to conform in outer configuration to that of the former or pattern |30.

If it is desired that the edge of the lens be ground so that the finished lens will be slightly larger or slightly smaller than the former used, the back-rest may be readily adjusted to accomplish this by turning the index wheel |40 to bring the index line thereon corresponding to the former a little to one side of the index line |43.

In mounting the lens between the heads I1 and I1 in proper alignment therewith, the first step comprises releasing the bearing support 28 by manipulating the hand wheel 58` in a direction to effect withdrawal of the lock pin 32 from engagement with the bearing portion 28 in the manner hereinbefore described. As the bearing supporting member 28 is thus released, the operator rotates said member by utilizing the case m^mber 91 as a handle to swing the spindle I8 from the horizontal position to a vertical position with the head I1 arranged above the bear,- i'ng support 28, as indicated by broken lines in Figure 7. This moving the head I1 to the upright position will bring the guidelines 26 and 26' into position to be readily viewed by the operator. As the spindle I8 is brought to the vertical position, ,the member 28 will be locked against further rotary movement by the engagement of the pin 32 in the aperture 33 in registration therewith as the operator releases the hand wheel 58.

The operator may now position the lens to be ground upon the head I1 and accurately center the lens with the head by utilizing the guide lines 26 and 26' in conjunction with the dots or other markings which are previously placed in the usual manner on the lens denoting the optical centers and the major and minor axes of the lens. After the lens has thus been properly placed upon the head I1 in engagement with the pad 25, the lens is secured to the head by any suitable means, such as the clamp A illustrated in Figure 8, by bringing one of the jaws, as a, into engagement with the lower face of the head I1, and the other jaw, as b, into contact with the upper face of the lens L, as indicated in Figure 7.

After the lens has thus been'placed on and secured to the head I1 by clamp A, the accuracy`of the relation of the lens to the head I1 may be readily determined by utilizing a sight opening |88 and the lens further adjusted, if necessary, relative to the head I1. Sight opening |88 is provided in the outer end of a bar or rod I8| secured to the carriage 28 in a plane over the axis of rotation of the member 28 and which has the sight opening |88 thereof arranged in alignment with the axis of the spindle I8 when said spindle is'in the vertical position.

After the lens L has thus been properly mounted upon the head I1, the member 28 is again released by the manipulation of the hand wheel 58 and then rotated to bring the spindle I8 to the horizontal position with the lens secured to the head I1 by the clamp A. As the spindle arrives at the horizontal position, the member 28 is locked against further rotary movement by the pin 32 as the operator rotates the hand wheel 58 in a direction to cause the spindle I8' to move inwardly toward the spindle I8 for bringing the head I1 into engagement with the lens for clamping said lensr between said head I1 and the head I1. After the lens has. been securely clamped by the heads I1 and I1', the clamp A is removed from the lens.

It will be observed, by referring to Figure 8, that the jaw member b is provided with a relatively large recess b which is of sufcient size to readily receive the head I'I therein when the clamp is in engagement with the lens carried by the head I1. The machine is now ready to operate for grinding the edge of the lens and, for this purpose, the wheel may be rotated by any suitable source of power operatively connected with the pulley 93.

As the abrasive wheel 5 is thus rotated, the carriage 28 is released by the operator moving the latch member |83 to bring the pin |85 out of cngagement with stop shoulder |86 and into alignthrough the medium of the pitman |I8. During the oscillation of the frame 22 and the carriage 28 connected therewith, the lens clamped between the heads I1 and I1 will be moved across the peripheral surface of the wheel 5 from adjacent one side thereof to the other side. During this movement of the lens across the face of the wheel 5, the lens will be swungfrom a position at the center of the peripheral surface of the wheel in substantially parallel relation with the wheel, as indicated by full lines in Figure 16, into more or less angular relation with the peripheral surface of the wheel as the lens approaches the outer edges thereof, as indicated by broken lines in Figure 16. It will, therefore, be seen that the lens is not only moved transversely across the peripheraly surface of the abrasive wheel from one side thereof to the other, but its angular rewheel is also constantly changing. This not only provides a maximum amount of travel of the lens for a minimum width of wheel, but a'lso provides for a maximum speed in the grinding operation. i

Furthermore, it will be noted that the' signal S will not only indicate to the operator when the' grinding of the edge is completed, but will also indicate to a certain degree the progress in the grinding operation being made. This latter result is due to the unground lens being more or less irregular in outline so that portionsof the lens edge will become ground before other portions and the signal S will be operated, intermittently prior to the completion of the grinding operation. To explain more explicitly the lens to be ground is usually cut prior to the edge grinding operation somewhat larger ln size than that desired for the nished lens. Each of these precut lenses after having been mounted in the lens holder is moved downwardly into operative position. The lens carried by the holder is held in contact with the abrasive wheel by the co-action of the adjustable weight |88 and the lens holder 6. This contact of the lens with the wheel maintains the pattern |38 out of contact with the back-rest |33 during the initial grinding ofthe lens. However, as hereinbefore stated certain portions of the edge of the lens will become ground -to the proper amount before other portions thereof, at which time the pattern will engage the back-rest and prevent further grinding of the finished portions of the lens. This intermittent enga-gement of the pattern with the backrest will of course cause intermittent operation oi' the signal S and the length of time between successive operations of the signal will gradually `35 lation with respect to the grinding surface of the by the more frequent engagement of the pattern rest is continuously maintained depressed by the former and the signal S remains in continuous operation thus-indicating that the grinding operation is completed.

Although I have shown and particularly described and preferred embodiment of my invention, I do not wish to be vlimited to the exact construction shown, as various changes, both in the form and relation of the parts thereof, may readily'be made without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. In a machine for grinding the edge of a lens, an abrasive wheel having a substantially flat peripheral surface and rotatable about a predetermined axis, a support for a lens holder movable about an axis in a plane extending substantially normal to said axis of rotation of the abrasive wheel, lens holder elements connected with said support to rotate about an axis substantially parallel with said axis of rotation of the whe'el for supporting a lens edgewise against the peripheral surface cf the wheel, the axis of movement of the support being substantially parallel with the radial line of the abrasive wheel passing through the point of contact of the lem; with said wheel, and power means for rotating said wheel and lens holder and for oscillating said support.

2. A machine for grinding the edge of a lens as in claim 1, having manually operable means for shifting said support about the axis of movement thereof independently of the oscillatory movement produced by the power means.

3. In a machine for grinding the edge of a lens, an abrasive wheel having a substantially flat peripheral surface and rotatable about a predetermined axis, va support for a lens holder including a frame movable about an axis in a plane extending substantially normal to said axis of rotation of the abrasive wheel, a carriage, rotatable lens holder elements connected with said carriage, means pivotally connecting lthe carriage with said frame whereby the carriage may swing about an axis substantially parallel with the axis of rotation of the abrasive wheel to move the lens holder elements toward and from the Wheel, the axis of movement of the fra-me being substantially parallel with the radial line of the abrasive wheel passing through the point of contact of the lens with said wheel, and power means i'or rotating said wheel and lens holder elements and for oscillating said frame.

4. In a grinding machine of the class described having asupport and an abrasive wheel mounted on said support to rotate about a horizontal axis, a frame, a carriage, a pair of spindles journaled in said carriage in coaxial relation with each other, clamping elements connected with said spindles normally spaced apart to receive the lens between them, means pivotally connecting the carriage with the frame whereby said carriage may swing about a horizontal axis to move the clamping elements toward and from the abrasive wheel, means pivotally connecting the frame to the support so constructed and arranged that the plane of swinging movement of the frame is substantially normal to the radial line of the abrasive wheel passing through the point of contact of the lens with said Wheel and power means for rotating said wheel and spindles and for oscillating said. frame.

5. In a grinding machine of the class described having an abrasive wheel, a rotary lens holder or former with the back-rest |33 until said backfor supporting a lens edgewise against the pe-I ripheral surface of the wheel, said lens holder including a pair of coaxial lens engaging means normally spaced apart for receiving the lens between them, and means rotatably supporting onc of said lens engaging means whereby the same may be swung out of coaxial alignment with the second one of said lens engaging means so that a lensmay be accurately positioned on said one of the lens engaging means.

6. In a lens edging machine having a rotary abrasive wheel, in combination, a lens holder for supporting a lens edgewise against the peripheral surface of the wheel comprising two opposed clamping heads arranged to receive the lens between them( means including a pair of spindles for rotating said heads, and supporting means for one of said spindles mounted to rotate about an axis extending substantially normal to the axis of rotation of the spindle whereby the head connected with said spindle may be swung into and out of cooperative relation with the other head. l

7. In a lens edging machine as in claim 6, manually operable means connected with the second one of said spindles for producing axial movement thereof to bring the head carried thereby toward and from the other clamping head for releasably clamping a lens between them.

8. In a lens edging machine as in claim 6. manually operable means connected with the second one of said spindles for producing axial movement thereof to bring the head carried thereby toward and from the other clamping head for releasably clamping a lens between them. and means actuated by said manually operable means including a locking element engageable with the supporting means for releasably maintaining said supporting means in either of two rotary positions.

9. In a lens edging machine having a rotary abrasive wheel, in combination. a lens holder for supporting a lens edgewise against the peripheral surface of the wheel comprising a pair of spindles, opposed clamping heads connected to said spindles to receive the lens between them, supporting means for said spindles including an element rotatably supporting one of the spindles and having movement with respect to the other spindle whereby the head connected with said one spindle may be moved into and out of axial alignment with the other spindle and head, and means for rotating said spindles in unison.

10. In a lens edging machine having a rotary abrasive wheel provided with a substantially fiat peripheral surface, a base, a support for said wheel mounted on said base for movement with respect to said base, a rotary lens holder, a support for said lens holder operatively connected with the base and including relatively swinging members mounted for movement with respect to said base to move the lens holder toward and from the abrasive wheel and to swing the lens holder across said surface of the abrasive wheel in a plane `substantially normal to the radial line of the wheel passing through the point of contact of a lens carried by the lens holder with said wheel, means connected with said wheel support for moving the abrasive wheel toward the lens holder, and separate means connected with one of said supports for maintaining the lens carried by the lens holder in predetermined pressure engagement with the abrasive wheel.

11. In a lens edge grinding machine, a base, a

Vin a plane extending substantially parallel with the axis of rotation of the abrasive wheel, a rotary lens holder, a carriage supporting said lens holder pivotally connected with the frame to swing the lens into and out of engagement with l the peripheral surface of the abrasive wheel, a former operatively connected with the lens holder to rotate therewith and to swing in unison with said carriage, a. back-rest for the former connected with the frame to swing therewith,said planeof swinging movement of the frame being substantially normal to the radial line of the abrasive wheel passing through the point of contact of the lens with said wheel for normally maintaining the lens in Contact with said wheel surface throughout the arc of movement of the lens independently of relative swinging movement of the carriage and frame, and power means for rotating the abrasive wheel and lens holder and for oscillating said frame.

12. A grinding machine as in claim 11, having means for adjusting the back-rest with respect to said frame.

13. In a grinding machine of the character described having an abrasive wheel, a lens holder for supporting a lens edgewise against the peripheral surface of the wheel, said lens holder including a pair of rotatable lens engaging means normally arranged in coaxial relation witheach other and adapted to be spaced apart for receiving the lens between them, rotatable means supporting one of said lens engaging means so that the same may be swung to an inoperative position out of coaxial relation with the second of said lens engaging means whereby a lens may be `readily placed thereon, and means having a hole therethrough arranged in xed predetermined relation with said one of the lens engaging means when in said inoperative position providing a sight opening by which the lens may be accurately positioned thereon.

14. In a grinding machine of the character described having an abrasive wheel, a rocking lens holder for supporting a lens edgewise against the peripheral surface of the wheel, said lens holder including a pair of rotatable lens engaging means normally arranged in coaxial relation with each other and adapted to be spaced apart for receiving a lens betweenvthem, supporting means for one of said lens engaging means having an axis of rotation substantially normal to the axis of rotation of said one of the lens engaging means so that said latter means may be swung to an inoperative position out of coaxial relation with the second of said lensv engaging means wherebya lens may be readily placed thereon, and means having a hole therethrough arranged substantially coaxial with said one of the lens engaging means when the same is in the inoperative position providing a sight opening by which the lens may be accurately positioned on said latter means.

l5. In a lens edge grinding machine, an abrasive wheel, a supporting means therefor, a carriage, means pivotally connecting the carriage to the supporting means whereby the carriage may have a limited swinging movement toward and from the abrasive wheel, a lens holder comprising a pair of spindles rotatably supported by said carriage, a former mounted on one of said spindles, a back rest connected with the support- ELI MAYNARD LONG.