US2247706A - Lens abrading machine - Google Patents

Description

July l, 1941. 1 w. GODDU LENS ABRADING MACHINE Filed Jan. 18, 1939 4 Sheets-Sheet 2 ATT NEY.

July 1, 1941.

L. W. GODDU LENS ABRADING MACHINE Filed Jan. 18, 1939 4 Sheets-Sheet 3 July l, 1941. W, GQDDU '2,247,706

LENS ABRADING MACHINE Filed Jan. 18, 1939 4 Sheets-Shee 44 INVENTOR. mvo /f/ 60am/ B Patented July 1, 1941 2,247,706 y LENS ABRADING MACHINE Lloyd W. Goddu, Southbridge, Mass., assigner to American Qptical Company,

Southbridge,

Mass., a voluntary association of Massachusetts Application January 18, 1939, Serial No. 251,541

Claims. (Cl. 5ll2i) rIhis invention relates to improvements in surfacing machines and has particular reference to a machine for surfacing ophthalmic lenses or analogous Work.

One of the principal objects of the invention is to provide improved means for controlling the pressure on the lens or work during the surfacing operation.

Another object is to provide improved means for surfacing curved surfaces wherein the operating parts will be simple, inexpensive and positive in their function.

Another object is to provide a machine of the above character with self-contained power generating means and simplified speed controlling means.

Another object is to provide a compound lever arrangement for regulating the pressure on the work or lens during the surfacing operation.

Another object is to provide novel means for holding the work guiding means in operative or inoperative position.

Other objects and advantages of the invention should become apparent from the following description taken in connection with the accompanying drawings and it will be apparent that many changes may be made in the details of construction and arrangement of parts without departing from the spirit of the invention as expressed in the accompanying claims. I, therefore, do not wish to be limited to the exact disclosures made as the preferred form only has been given by way of illustration.

Referring to the drawings:

Fig. I is a front elevation of the machine embodying the invention;

Fig. II is a side elevation of said machine showing the means for controlling the pressure on the work in operative position;

Fig. III is a plan view of said device; and

Fig. IV is a fragmentary side elevation showing the work guiding lever and pressiue control means in inoperative position.

Machines of the character described are adapted particularly for use in forming spherical surfaces and are used primarily for forming highly polished surfaces.

Several different arrangements have been provided in the past for controlling the pressure on the work during the surfacing operation. In most commercial machines a spring pressed plunger was used in combination with means for varying the tension of the spring and thereby controlling the pressure exerted on the Work or lens during the surfacing operation. Such arrangements, due to the variation of the surface curvatures being generated, and through the movement cf the work or lens from a high to a low spot on the face of the tool, cause the pressure to be uneven. It is apparent that when a spring pressure is used and when the work is moved to a high position on the tool the tension of the spring will be increased beyond that which exists when the work or lens is moved to a low position on the tool. Such devices were also quite complicated and expensive in structure.

One of the primary objects, therefore, of the present invention is to overcome the above undesirable feature by the provision of relatively simple and inexpensive means whereby the pressure on the work or lens may be quickly and easily controlled and with which the said pressure will be substantially equal throughout all positions of movement of the work or lens during the surfacing operation,

Referring more particularly to the drawings, wherein like characters of reference designate like parts throughout the several views, the device embodying the invention comprises broadly a base i having a tool supporting spindle 2 adjacent one end thereof and a compound lever 3 pivotally attached to a stud e adjacent its opposite end.

The spindle 2 is threadedly connected at 5 to the stud shaft of a suitable gear reduction assembly il driven by a motor l. A bowl 8 is also connected, as by screws or other means 9, to a flange it on the adjacent threaded end 5 of the stud shaft. The bowl 8 and spindle 2 are adapted to be simultaneously rotated by the motor 'l through the gear reduction i5. A tool il having the desired surface curvature l2 thereon, which is to be formed on the work or lens E3, is attached to the spindle 2 and is adapted to be rotated therewith.

The work or lens i3 is attached to a suitable block ill by pitch, or other holding means such as adhesive or mechanical means. The block r lil has a .tapered depression l5 in its upper sur- 'Ihe holding device I9, as illustrated in Figs.

I, II .and III, lconstitutes a boltlike member 2I which extends through a slot 22V in the end of the arm 2U, The vboltliike member ZI has a hea-d 23 provided with a perforation in a sleeve 24 which f1ts over said head 23 in which the rod I8 extends. The opposite end of the bolt 2| is threaded and is provided with -a suitable clamp nuit 25.

The above arrangement provides means whereby the rodlike member I8 may be adjusted longitudinally in the aligned openings in the head 23 and sleeve 24 .and may be seit to different angular positions or move-d to dilerent positions longitudinally of the slot 22 in the arm 20. .en

eccentric adjustment may also be imparted Ato the pin I1, :due to the lateral or ofi-center portion 49 of the rod I8. The above adjustments are accomplished by loosening the nut 25 which allows the rod I8 to be slid freely within the aligned openings in the head 23 and sleeve 24 and which also allows the bolt 2l .to be rotated in or moved longitudinally of the slot 22. When in desired adjusted position the nut 25 is tightened causing the head 23 to be drawn inwardly of the sleeve 24 tending to move the normally aligned openings in s-aid head 23 and sleeve 24 out .of alignment and thereby cause the walls of said openings to grip and hold the rod I8 in adjusted position. This adjustment also simultaneously moves the inner face of the sleeve 24 into engagement wi-th the side surface of the arm 20 and thereby locks the bolt 2l `against rotation and against movement relative to said arm.

The arm 2i) lis of a substantially S shape having a kbifurcated portion 26 pivoted at 21 to a sleeve 28. The sleeve 23 is rotatably supported on the stud 4. Suitable spaced needle bearings 29 and 30 are provided to permit free rotar; movement of the sleeve 28 on said stud. The bifurcated portion, adjacent its base, is provided with aligned vertically extending slots 3l. The slots 3l each have 'an offset portion 32 adjacent their upper end Vand an offset portion 33 :adjacent their lower end. The opposite walls of the slots are provided with .a recess 34. The function of said osets andrecess will be described hereinafter.

A lever 35 of the rst kind is pivoted at 35 to Van arm 43 extending from the sleeve 28 and lying between the branches of the bifurcated portion 23. The lever 35 has a link member 31 pivot-ally connected thereto, .as illustrated at 38. The lever 35 has a troughlike end 39 in which a weight 45 is slidably supported. The link 31 is positioned between the branohesof the bifurcated portion 26 and has an opening adjacent its upper end in which a pin 4I is adapted to be fitted by extending the said pin through the slots 3|,

When the pin 4I is positioned in the off-set 33, as illustrated in Fig. IV, the arm 20 is hel-d in a raised position away from the surfacing tool II. It is to be noted that when in this position the lever 35 is resting upon the upper end of the stud 4.

When the pin 4I is in the offset 32, Aas shown in Fig..II, the lever 35 is raised so that the action of gravity Von the weight '43 will be transmitted through the link connection 31 VtoV the arm 20 causing the said arm .to move downwardly about its pivotal connection 21 under the action of the weight .40. This lcauses thepin IB to 'exert a pressure on the lens or work I3 during the surfacing operation. The amount of pressure may be varied by movement oftthe weight 4I) longitudinally of its troughlike support 39. It is apparent that when the weight 40 is moved toward the pivotal connection 33 the weight or downward pull on the lever arm 20 will be decreased and vice versa. It should be noted that the n'ature of the lever arrangement allows a much less cumbersome :an-d heavy Weight `t-o be used without changing the effect on the spindle I8 than if a direct leverage was used. This leverage provides .a ratio of approximately one to iive between the weight and the spindle pressure. This ratio is varied yas the weight 4!! i-s moved along `the trough 39. It Iis also noteworthy that the use lof `a weight and leverage gives a constant pressure on the lens at all times during the grinding or surfacing of a lens.

To obtain the initial required length of the pin I3 to clause the lever 35 and weight 40 to assume th-e desired angular position and clearance from `the end of the stud 4, the pin 4I is position-ed in the recess 34. This holds the arm 2B at the desired height when the lever 3971s restv ing upon the upper end of the stud 4.v The nut 25 is then loosened and the pin I8 adjusted to position i'ts tapered end I6 in the recess I5 of the block. The said pin vis simultaneously a'djusted 'to the desired angle, and to the vdesired oli-center position. Referring to the desire-d angl-e mentioned above, it is usually most desirable t-o line the pin i3 radially with the center of curvature of the lap curvature I2. When adjusted to Vdesired position the nut 25 is tightened to hold the pin I8 in positive fixed rel-ation with the arm '23. The lever 35 and weight 40 is then raised an amount sufficient to Aallow the pin I8 to be lin positive fixed relation with 'the arm 23. The lever 35 and weigh-t 43 is then raised an amount sufficient to allow the pin 4I, oarried by the upper end of the link 31, to be posi'tio-ned in the offset 32. This cau-ses the Weight 43 to exert a pressure on the lever 35, which pressure is transferred through the link 31 to the arm 20.

The arm 46 is provided with an intermediate slotted portion having spaced surfaces 42. A suitable ball bearing 43 is mounted on an eccentric shaft 44, as illustrated in Figs. II and III. The shaft 44 is driven by a suitable reduction gear system contained in a housing 45 and operated by the motor 1.

The reduction gear system contained in the housing 6 and which is also driven by the motor 1 is such as to rotate the surfacing tool Il at a much greater speed than the speed of rotation of the eccentric 44 as brought about by the gearing in thehousing 45. The difference between the ratio of speeds is approximately 6 to 1. It is to be understood, however, that these ratios may be Varied and controlled. Y

Rotation of the eccentric 44 through the reduction gearing in the housing 45 causes the arm 20, pivotally connected to the sleeve 28, to be oscillated in a direction transversely of the surfacing tool I I. The amount of oscillation is such as to cause the lens or work I3 to move transversely of the tool during the rotation of said tool an amount suioient to surface the entire surface of the work or lens in engagement with said tool.

The gearings in the housings E and 45 are not shown because they are of the conventional commercial type; the only difference being, in this particular instance, that the two sets of gearing are driven by a single source of power.

The operation of the device lis substantially as follows:

The work or lens I3 to be surfaced is secured to a suitable holder or block I 4 by a layer of pitch or other desirable adhesive or mechanical holding means. A surfacing tool Il having the desired surface curvature on the face I2 thereof, which is to be formed on the work or lens I3, is placed on the spindle 2. A suitable tapered connection between the shaft 2 and tool automatically locks the tool in desired centered position.

The pin 4I is then positioned in the recess 3d of the arm 28 so as to cause the said arm to be locked in an initial set position. VThe pin It is then adjusted to position the tapered end thereof in engagement with the block Il within the recess I5. The pin supporting means is then adjusted longitudinally of the slot 22 to vary the effective length of the arm 26 or the distance between the tapered end I8 and the axis of rotation of the sleeve 28, of the stud Il. This adjustment longitudinally of the slot 22 increases or decreases the arc of the line of movement of the work or lens I3 in a direction transversely of the tool. The pin supporting means is then adjusted longitudinally of itself and rotated to provide the desired eccentric position. When in desired adjusted position the nut 25 is tightened to secure the pin in adjusted position. The lever 35 is then raised to position the pin 4I within the offset 32 an-d in engagement with a hooklike shouldered surface 41 in said offset. The weight d@ is then adjusted longitudinally of its troughlike support 39 to regulate the pressure on the work or lens I3 during the surfacing operation.

Power is then directed to the motor 'I by means of a switch or other suitable means 33 connected with a suitable source of energy. Rotation of the motor 'I causes the spindle 2 and tool I I carried thereby to be rotated at a given speed controlled by the reduction gearing in the housing S and simultaneously causes the eccentric 44 to be rotated at the desired speed controlled by the gearing in the housing 45. A suitable surfacing or polishing compound is applied tc the surface I2 of the surfacing tool during the surfacing operation. This may be in the form of a liquid mixture of rouge or the like which may be poured on to the face of the tool.

It may be pointed out that the weight 4G, adjustably positioned on the lever 35 in the trough 39, lies substantially directly over the lever system pivot 4. This provides a swinging lever system with no appreciable inertia and greatly reduces wear due to pressure and vibration,

From the foregoing description it will be seen that simple, erlicient and economical means and method have been provided for accomplishing all of the objects and advantages of the invention.

Having described my invention, I claim:

l. In a device of the character described, the combination of a base having a tool rotatably supported adjacent one end thereof and work holding means adapted to receive a piece of work for engagement with said tool, a sleeve pivotally supported adjacent the opposite end of said base, a projection on said sleeve, an arm pivotally connected to said sleeve for pivotal movement about an axis substantially normal to the axis of rotation of said sleeve, a work holder engaging member on said arm, a lever pivotally connected to the projection on said sleeve, a link connecting said lever to said arm, weight means on said lever for causing the arm to be urged under the pressure of said weight toward the surfacing tool and means for relieving the pressure of said weight on said arm and for holding said arm out of operation.

2. In a device of the character described the combination of a base having means for supporting a tool, means for holding work on said tool, a lever having a pivotal connection with said base for movement toward and away from the tool and for movement in a direction substantially normal to said rst movement and across the face of the tool, a control member mounted to follow said normal movement, said lever hav-- ing means adjacent its end opposite its pivotal connection for engaging the Work holding means, a second lever pivotally supported on said conltrol member intermediate the ends of said first lever, said second lever having means connecting said second lever with said rst lever at a point removed from the pivotal connection of said second lever and a weight supported by said second lever for movement longitudinally thereof.

3. In a device of the character described the combination of a base having a tool supported thereon, a Work holding mema'ber adapted to receive a piece of work for engagement with said tool, a sleeve pivotally supported on said base at a point spaced from the tool, an arm pivotally connected to said sleeve for pivotal movement about an axis substantially normal to the of rotation of said sleeve, a work holder engaging member on said arm adjacent its end opposite its pivotal connection with said sleeve, a projection on said sleeve extending in the direction of said arm, a lever pivotally connected to the projection at a point intermediate the ends of said arm, a link connecting said lever to said arm at a point removed from the pivotal connection of said lever with said projection and weight means on said lever movable longitudinally thereof toward and away from the pivotal connection of the arm with said sleeve.

4. In a device of the character described the combination of a base having means for supporting a tool, means for holding work on said tool, a lever having a pivotal connection with said base for movement toward and away from the tool and for movement in a direction substantially normal to said first movement and across the face of the tool, said lever having spaced engagement portions intermediate its ends and means adjacent its end opposite its pivotal connection for engaging the Work holding means, a control member mounted to follow said normal movement, a second lever pivotally supported on said' control member intermediate the ends of said first lever, said second lever having means selectively engageable with the engagement portions of the rst lever for connecting said second lever with said first lever at a point removed from the pivotal connection of said second lever and a weight supported by said second lever for movement longitudinally thereof.

5. In a device of the character described the combination of a base having a tool supported thereon, a sleeve pivotally supported on said base at a point spaced from the tool, an arm pivotally connected to said sleeve for pivotal movement about an axis substantially normal to the axis of rotation of said sleeve, a work holder engaging member on said arm adjacent its end opposite its pivotal connection with said sleeve and vertically spaced engagement portions located intermediate the ends of the arm, a projection on said sleeve extending in the direction of said arm, a lever'pivotally connected to the projection at a point intermediate the ends of said arm, a link on said lever for selectively connecting said lever to said spaced engagement portions of said arm ata point removed from the pivotal connection of said lever with said projection and Weight, means on said lever movable longitudinally thereof toward and away from the pivotal connection of the arm with said sleeve, the connection of said link with one of said engagement portions of the armbeing adapted to cause said arm to receive the pressure action of the weight and the connection of the link with the other of said engagement portions being adapted to relieve the arm from the pressure action of the Weight and beingadapted to hold said arm away from the tool.

6. In a device of the character described the combination of a base having means for supporting a tool, work holding means adapted to receive a piece of work for engagement with said tool, a lever having a pivotal connection with said base for movement toward and away from the tool and for movement in a direction substantially normal to said first movement and across the face of the tool, said lever having means adjacent its end opposite the pivotal conneotion for engaging the work holding means, a control member mounted to follow said normal movement, a second lever pivotally supported on said control member intermediate the ends of said first lever, said second lever having means connecting said second lever with said first lever at a point removed from the pivotalconnection of said second lever, a weight supported by said second lever for movement longitudinally thereof and means in cooperative relation with said levers for imparting controlledl movement of the rst lever in a direction transversely of the tool,

7. In a device of the character described the combination'of a base having a tool supported thereon, work holding means adapted to receive a piece of Work for engagement with Isaid tool, a sleeve` pivotally supported on said base at a point spaced from the tool, an arm pivotally connected to said sleeve for pivotal movement about an axis substantially normal to the axis oi rotation dof said sleeve, a work holder engaging member onsaidvV arm adjacent its end opposite its pivotal connection with said sleeve, a projection on said sleeve extending in the. direction of said arm, a lever pivotally connected'to the projection at a point intermediate the ends of said arm, a link connecting said lever to said arm at a point removed from the pivotal connection of said lever with said projection, weight means on said lever movable longitudinally thereof toward and away from the pivotal connection of the arm with said sleeve, and means engagingsaid projection for moving said projection and levers in a direction transversely of the tool.

8. In a device of the character described the combination of a hollow base, a tool support rotatably mounted on said hollowV base, a tool on said tool support, work holding means adapted to receive a piece of Work for engagement with said tool, a sleeve pivoted to said base about a verti` cal axis spaced from the tool support, a first lever pivoted to said sleeve aboutJ a'horizontal axis, said lever having means adjacent its end opposite its pivotal connection with said sleeve for holding Work in engagement with the tool, said first lever having vertically spaced engagement v otally connected to said second lever at a point removed from the pivotal connection of said second lever with the projection, said link having a portion adapted to be engaged with either of the spaced engagementrportions of said first lever and a weight supported on said second lever for movement longitudinally thereof toward and away from the pivotal connection of the sleeve to the base.

9. In a device of the character described the combination of a hollow base, a tool support ro-V tatably mounted on said hollow base, a tool on said -tool support, work holding `means adapted to receive a piece of Work for engagement with said tool, a sleevepivoted to said base about a vertical axis spaced from the tool support, a

first lever pivoted toy said sleeve about a horizontal axis, said lever having means adjacent its end opposite its pivotal connection with said sleeve for holding work in engagement with said tool, said rst lever having vertically spaced engagement portions intermediate the ends thereof, a projection on said sleeve extending in the direction of said rst lever, cam means mounted on said base for engagement with said projection, a second lever pivoted to said projection Vand extending from said pivotal connection in a di` rection toward the pivotal connection ofthe sleeve With said base, a link pivotally connected to said second lever at a point removed from the pivotal connection of said second lever with the projection, said link having a portion adapted to be engaged with either of the spaced engagement portions of said rst lever and means internally of said base having a driving connection with the tool support for rotating said tool and having a driving connection With said cam means yengaging said projection on said sleeve for rotating said cam to impart an oscillatory movement to said projection and to the levers associa-ted with said projection for moving said iirst lever in a direction transversely of the tool.

10. In a device of the character described, the combination of a base having mounted thereon a tool support, a cam member, a horizontally and vertically pivoted lever, and a control member mounted to follow the horizontal movement of said lever, an abrading -tool on said support, work holding means adapted to receive a piece of work for engagement with said tool, said control member having a portion in operative engagement with said cam, said lever having Aa portion for supporting work on said tool, a second lever member pivotally supported on said control member and intermediate the ends of the rst lever and having an adjustable weight at one end thereof, a link member connecting said levers at a point removed fromthe pivot of the second lever, spaced engagement portions on said rst lever for engaging :the said link member and thereby hold the levers in desired positions relative to each other, and means for actuating the said tool support and cam member whereby said cam member acts on said leversto 'cause them to oscillate transversely relative to the tool.

LLOYD W. GODDU.

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