US3782042A

US3782042A - Lens grinding and polishing units

Info

Publication number: US3782042A
Application number: US00268914A
Authority: US
Inventors: R Strasbaugh
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-07-03
Filing date: 1972-07-03
Publication date: 1974-01-01
Anticipated expiration: 1991-01-01

Abstract

A lens grinding and polishing unit wherein either the workpiece or lap is supported by a laterally oscillatable head and the other is held atop a non-rotating flexible spindle (e.g. aluminum) which is simultaneously flexed at different speeds and courses in a repetative pattern compounded by rotation thereabout of (a) an inner tubular housing which eccentrically embraces the spindle at a circumference intermediate its length, and (b) an intermediate tubular housing spaced outward from the inner housing and which eccentrically bears on the inner housing adjacent the same circumferential area, separated from the inner housing by a ball bearing raceway. The intermediate housing is outwardly surrounded by a fixed housing from which it is separated by another ball bearing raceway, and all three generally concentric housings are mounted within an outermost dome of somewhat flexible material, the dome being supportingly transected by the spindle at a circumference between the carried lap and the top of the inner rotatable housing, so as to be jointly flexed by oscillation of the spindle. Both rotatable housings are pulley-operated from an electric motor which also oscillates the head (carrying the workpiece), thus totally eliminating cam and gear mechanisms previously employed in polishers. Adjacent units located in a cabinet can be operated by a single motor. Such units also carry a pneumatic element to supply down-pressure for the head, and provide circulation of lubricating fluid to the lap.

Description

United States Patent 1 1 Strasbaugh I LENS GRlNDlNG AND POLISHING UNITS [76] Inventor: Ray Howard Strasbaugh, 3400 Airport Way, Long Beach, Calif. 90806 [22] Filed: July 3, 1972 [21] Appl. No.: 268,914

Primary ExaminerDonald G. Kelly Artorney-Howard L. Johnson [57] ABSTRACT A lens grinding and polishing unit wherein either the workpiece or lap is supported by a laterally oscillatable head and the other is held atop a non-rotating 1 Jan. 1, 1974 flexible spindle (e.g. aluminum) which is simultaneously flexed at different speeds and courses in a' repetative pattern compounded by rotation thereabout of (a) an inner tubular housing which eccentrically embraces the spindle at a circumference intermediate its length, and (b) an intermediate tubular housing spaced outward from the inner housing and which eccentrically bears on the inner housing adjacent the same circumferential area, separated from the inner housing by a ball bearing raceway. The intermediate housing is outwardly surrounded by a fixed housing from which it is separated by another ball bearing raceway, and all three generally concentric housings are mounted within an outermost dome of somewhat flexible material, the dome being supportingly transected by the spindle at a circumference between the carried lap and the'top of the inner rotatable housing, so as to be jointly flexed by oscillation of the spindle. Both rotatable housings are pulley-operated from an electric motor which also oscillates the head (carrying the workpiece), thus totally eliminating cam and gear mechanisms previously employed in polishers. Adjacent units located in a cabinet can be operated by a single motor. Such units also carry a pneumatic element to supply down-pressure for the head, and provide circulation of lubricating fluid to the lap.

10 Claims, 13 Drawing Figures PATENTEUJAN 1 1974 sum 3 0F 4 I PATENTEUJAN H914 3,782,042

SHEET u [IF 4 LENS GRINDING AND POLISHING UNITS Grinding and polishing devices such as those used for surfacing optical lenses utilize an opposing pair of mutually aligned supports, one holding the workpiece or lens blank and the other holding a lap, the curvature of which lap it is desired to duplicate on the workpiece by frictional engagement or rubbing the two faces together until they minutely conform. Usually both supports are mechanically moved at the same time, at as rapid a speed as practical, and in somewhat different paths for each of the supported objects, with the path of at least one of the objects desirably being adjustable as to amplitude or span. Such results have been obtained in the past by various arrangements of gears, cams, tracks, etc. which in addition to initial cost and complexity of fabrication, also exhibited the natural tendency of interacting mechanisms to require repeated or continuous attention and realignment.

In contrast, by the present construction a single electric motor plus drive pulleys operate both the work support and lap support at diverse speeds and courses without the use of gears, cams or set tracks; the lap is simultaneously moved in two paths each at a different speed; in addition, if desired, a plurality of such adjacent units can be operated from the same motor. A basic feature is the employment as one of the supports (typically the one holding the lap) of a flexible upright rod or fixed spindle (provided by resilient metal), which spindle and lap are caused to vibrate by rotation of an embracing ring structure (tubular housing) circling about it, an intermediate length of the spindle eccentrically transecting the annular top of the housing. Laterally surrounding this inner housing is located another, rotatable, intermediate housing which eccentrically surrounds the top of the inner housing and is separated therefrom and from an outer fixed housing by ball bearing raceways.

By its rotation at a different (usually slower) speed from that of the inner housing, the intermediate housing overridingly moves the vibrating inner housing (plus its embraced spindle and carried lap) in a larger, generally annular path. The vibrating spindle is additionally annularly supported or embraced at a circumferential area which is between the lap and the top of the rotating inner housing, by a fixed dome-like structure (typically a vibratable rubber seal) which is thus flexed transversely in unison with and by the vibrating spindle which it supports. The flexible dome thus outwardly and laterally overlies the three tubular housings which spacedly surround the spindle, of which the inner two are driven by separate pulleys and which bear directly and indirectly respectively on the spindle.

At the same time the workholding support, pressing down upon the lap with a selected pressure (provided by a pneumatic unit), can be oscillated from side to side a variable amplitude) by pulley drive means activated by the same motor. A supply steam of conventional abrasive fluid or slurry directed to the face of the lap may also be provided.

Accordingly, the composite pattern of spindle vibration produced by the pair of eccentrically engaging rings formed by the tops of the tubular housings (FIG. 12), which pattern is swept back and forth from side to side by oscillation of the overhanging support arm (with a small phase difference at each oscillation), produces the pattern shown in FIG. 13. Structurally, amplitude adjustment for the overhanging rocker arm can be effected by a simple turnbuckletype tie-rod which forms a link in the drive pulley assembly. The accompanying drawings show a cabinet assemblage of several, identical, simultaneously operable, grinding and polishing units of the present invention in their presently preferred form.

FIG. 1 is a front elevational view of a four-unit lens grinder and polisher FIG. 2 is an end elevational view as seen from the right of FIG. 1.

FIG. 3 is a top plan view of the same.

FIG. 4 is an end elevational view as seen from the left of FIG. 1.

FIG. 5 is a rear elevational view thereof.

FIG. 6 is a transverse vertical sectional view through one unit of the assembly showing a flexible-spindlesupported lap and opposing oscillating head with a toric workpiece (lens) mounted therebetween.

FIG. 7 is a bottom plan view of the pivotal mount taken along line 7-7 of FIG. 6.

FIG. 8 is a horizontal sectional view taken through an adjacent pair of jointly operable units of the assembly as seen along the staggered line 8-8 of FIG. 6.

FIG. 9 is a bottom view of the spindlemounted lap taken along the line 9-9 of FIG. 6.

FIG. 10 is a horizontal sectional view through a flexible spindle taken along the line 10-10 of FIG. 6.

FIG. 11 is a longitudinal vertical sectional view taken through the rear portion of the assembly as seen along the line llll of FIG. 8.

FIG. 12 is an actual pattern of oscillation made by attaching a pen to the work support in touch with paper fixed atop the lap, with the spindle being vibrated by the nested pair of rotating housings and the overhead pen-holding arm kept stationary.

FIG. 13 is the pattern produced by additionally oscillating the pen-holding arm for two complete oscillations, with the spindle vibrating as in FIG. 12.

The four-unit assembly of FIGS. 1-5 is housed in a generally rectangular cabinet C formed of

upright end walls

20, 21, a cross-connecting rear wall 22 with removable panel 23, staggered

longitudinal front panels

24, 25, a mutually aligned pair of side-hinged front closures 26, 27, and lower (28) and upper (29) horizontal shelves located in stepped relation. An elongated, rectangular housing 17 internally containing control elements, is centrally suspended lengthwise above the length of the top shelf 29 by means of a pair of tubular cylindrical supports l8, l9, rising from the shelf.

Four open-top and open-bottom

cylindrical wells

30, 31, 32, 33, each serving to house a polishing unit, arise vertically, laterally spaced apart, upstanding from the lower shelf. To the rear of each well, spaced forward from the vertical panel 25 is a corresponding number of upstanding, generally rectangular, open-back,

hollow posts

35, 36, 37, 38, each supported by a respective horizontal stud 39 movably projecting through the lower margin-of the upright panel wall 25 and lodged in the floor 40 of the post, being anchored to the rear face of the wall 25 by a bracket plate 34 which holds it in a ball bearing raceway 41. The two side walls 42, 43 (FIGS. 2, 6) of each post are connected by a flat top plate 44, and the front wall 45 of the post is of lesser height than the adjacent side walls so as to leave an open fore-and-aft passage or channel 46 beneath the top wall 44, which channel is horizontally traversed by 3 a shaft 47 inserted through the

opposite side walls

42, 43.

A generally horizontally disposed rocker arm 50 is carried by the shaft 47, with a forwardly-projecting portion 51 extending outward from the channel to spacedly overlie the open top of the particular well 30. The rearward portion 52 is vertically forked to receive a transverse pivot pin 53 which transects the piston stem 54 of a pneumatic chamber 55, the opposite end of which is pivoted on a transverse shaft 56 which is inserted through the opposite side wall of the post above the bottom wall 40. In operation, a selected pressure is set (as by valve means) for each particular cylinder 55 to continually apply to the forward portion 51 of the rocker arm, which down-pressure is thus exerted on the workpiece, being supplied to the chamber 55 through a conduit 57 from an air compressor of source of pressurized gas-not shownwithin the cabinet. At the same time, the arm 50 can automatically rock or oscillate the necessary amount to conform with changing curvature defined by the frictionally engaged lap and workpiece.

The forward end of the rocker arm 51 is formed with a short closed-end vertical slot or guideway 58 which receives an externally threaded tubular shaft 59 anchored by an overlying washer 48 and nut 49, with the head 60 of the shaft press-fit in the end of a fluid conduit 61 which serves to deliver (from a conventional pump and reservoir not shown-rwithin the cabinet) cutting oil or abrasive slurry to the workpiece within the well. For initial positioning, the shaft 59 is slidable along the length of the slot 58. The lowervend of the shaft 59 is threadedly inserted in a vertical bore 63 of a positioning block 64 which, by action of the screw 59, has its flat top 65 drawn up against the underface of the rocker arm 51 so as to lock the head 60 and block 64 at a selected location along the slot 58.

The lower extremity of the block 64 is bifurcate with its two

arms

66, 67, each traversed by a respective mutually opposing conic-ended

screw

68, 69, anchored by

nuts

70, 71, the pair of screws serving as transversely aligned pivots for a two-pronged down-pressure exerting coupling plate 72. The latter is essentially a rectangular plate, thus pivoted between the

arms

66, 67, and downwardly threadedly traversed by a pair of pointed screws 73, 74, which are anchored by lock nuts 75, 76. The pointed ends of the screws 73, 74 are removably inserted in corresponding sockets 77 of a saddle 78, to the concave bottom of which is temporarily cemented the workpiece or lens 80 which is to be surfaced. The combination of

horizontal pivots

68, 69, with vertical pivots 73, 74, thus provides a self-aligning universaltype mounting for the saddle 78 and workpiece 80.

Centered beneath each well (30-33) in the area of the cabinet which is immediately above that exposed upon opening the hinged closures 26, 27, is an attachment coupling 82 having a layer or sandwich of shockabsorbing material 62, and by a fastening element 82a secured to an extension arm 83 which by coupling means 84 is bolted to an inturned marginal strip 85 of the front panel 24, and by coupling 79 and upright arm 82 is fastened to the cabinet wall 28. The mounting element 82 has a top-opening cylindrical insertion socket 86 adapted for thrust-insertion of the bottom end of a flexible cylindrical rod or (non-rotating) spindle 87 which may be fabricated of metal such as aluminum.

4 The spindle is formed with a spline or keyway 88 for anchorage in the socket by means of a set screw 89.

Within each wall (33-33), the flat housing wall 28 is centrally apertured at 90 and overlaid by an annular,

horizontal wall 91 forming the floor of the well (which I is also centrally apertured), the wall 91 by means of an annular rabbet joint 92 serving to anchor within the well a generally dome-shapedcap or flexible shield 93. The dome 93 is molded of elastomeric material such as neoprene; its apical area internally is axially thickened to form a dependent boss 94 which is centrally apertured as coaxial bores 94a, 95 of different diameters which snugly receive lengths of corresponding thickness of the spindle 97 which thus vertically transects the dome and anchors the latter as an envelope-like seal against entry of foreign matter (such as drilling fluid) from above. Accordingly, the dome 93 and flexible spindle 87 are vibrated laterally in unison by the mechanism which shakes thespindle, as hereafter described.

Spacedly located within the dome 93 is an invertedcup-shaped fixed structure or housing 96 characterized by an external peripheral shoulder 97 disposed in abutment with an inturned footing flange 98 of the dome, and therebeneath having an outward extending annulus 99 which is clamped together with the superposed housing wall 28 and the well-floor 91 by a circle of bolts 100. The flat top 101 of the cup 96 is centrally apertured at 102 and loosely overlaid by a transversely slidable washer 103 (conveniently of leather) which snugly embraces the spindle 87 so as to close theaperture 102.

Rotatable about a circumferential length or segmental area D of the fixed spindle 87, is a generally flat, annulus or ring structure 105 which is eccentrically. apertured at l06for sliding insertionof. the spindle- The bored annulus 105 forms the upper part of a twopiece rotatable tube 107 which is thus spaced outward surrounding the spindle. lts lower end 108 is threadedly mated to a dependently continuing, tubular structure 109 which there loosely surrounds the spindle and terminally (distally) carries a radially-projecting pulley 110. At the opposite ends of the upper tube portion 107 are ball bearing raceways 111, 112 anchored by snap rings 113, 114 and spacer 104. Accordingly, as.

the eccentric ring 105 revolves about the fixed spindle 87 at D, the spindle necessarily flexes transversely.

Within the larger, flexible dome 93 and spacedly surrounding the inner rotatable tubular structure 107, 109, is an intermediate, nested, tubular structure 115, terminally carrying a bottom radially-projecting pulley 116 of greater diameter than the inner pulley 110, and in comparison constituting a slow" pulley. The upper end of the tube is formed as an inward stepped structure 117 which is outwardly separated from the housing cup 96 by a ball bearing raceway 119.

Each outer race is shock-supported by a pair of 0-

rings

120, 121 and 122, 123 respectively, the inner races being held in place by snap rings 124, 125. A ball bearing raceway 126 separates the inner tube 109 and the lower end of intermediate tube 115, held by snap rings 127, 128 and O-ring 129. It will be seen that the slanted, rotating intermediate tube or housing 115, 117 does not directly contact the spindle 87, but through the two bearing

raceways

119, 126 it bears upon the inner rotatable tube 107, 109 as a second ring in such manner that the eccentricity of the segment 117 transfers an overriding vibrational pattern to the area D of the spindle through the intermediary of the embracing annulus 105. This composite movement, together with the oscillation of the rocker arm 50 as subsequently described, produces a characteristic pattern of movement of the spindle (.and lap 172) relative to the workpiece 80.

The top end of the flexible spindle 87 which projects through and above the cap 93 is inserted in the bottomopening bore 160 of a lap-holding jig or mount 161 and terminally secured by a threaded bolt 162 inserted downward through a narrow bore 163 into a tapped socket 164 of the spindle. The latter is also formed with a short keyway 165 which receives the end of a lock pin 166, inserted in a transverse channel 167 of the mounting block 161. Disposed adjacent opposite sides of the block 161 are a pair of

clamp jaws

168, 169, the latter with a laterally projecting lever arm 170 (FIG. 9).

The lap 172 is formed with a convex top workcontacting surface 173 and a central concavity 174 in an otherwise flat bottom 175 with the cavity disposed to overlie the head of the bolt 162. The clamp jaws are held against opposite side grooves or

channels

176, 177 of the lap, by

respective screws

178, 179 received in tapped

apertures

180, 181 of the block, the left screw 179 carrying a helical spring 182 which can be compacted toward the head (so as to open the jaws and release the lap) by pressure on the lever 170, the jaw 169 pivoting on an aligning pin 171 which is lodged in the mount 161 opposite to the pin 166.

The small pulley 110 rotates the innermost tube 107, 109 at a multiple (such as seven to times) of the rotational speed at which the intermediate tube 115, 117 is rotated by the large pulley 116. By the present construction, two adjacent units are operated by the same motor M (FIG. 8), which with the drive shaft 132 is supported inward from the rear wall 22 of the cabinet by an adjustable, yoke-shaped positioning bracket 133, pivoted at 130 for tightening the pulley belt by lock nuts 131. A belt 134 from the drive pulley 135 operates two

horizontal pulleys

136, 137, and by the stretch 134a, also moves the respective unit pulleys 110. The respective upright-extending

shafts

138, 139 of the horizontal pulleys are journalled in vertically-separated pairs of pillow blocks 140, 141, which shafts also carry small pulleys 142, 143, which by

respective belts

144, 145 operate the slow unit pulleys 116.

The

belts

144, 145 are also stretched over respective pulleys 184, 185 (FIG. 11) which are carried by

upright shafts

186, 187 journalled in brackets of

plates

188, 189, each having a rearward, vertically disposed

hinge strip

196, 197 swingably held between a pair of threaded pivots 198 which traverse respective suspension arms 199 (hung from cabinet wall 25) secured by lock nuts 200. The opposite vertical margin of each

plate

188, 189 is secured in a belt-tightening position by a lock nut 146. The top of each shaft carries a radially sloted

head

190, 191 formed with an inverted-T- shaped guideway 192 which receives the stud shaft of a pivot coupling 193, being secured at a selected position along the slot 192 by a bolt 194 and washer 195.

Each cylindrical, horizontal stud 39 which forwardly supports a respective pneumatic post (35-38), as earlier noted, is supported by a bearing mount 34 after traversing the cabinet wall 25. From here it extends rearward, spanning the interior of the cabinet to the rear wall 22 where it is journalled in a fixture 147. Adjacent the bearing raceway 41, the rotary shaft 39 traverses a radially upstanding lever arm 148 which is dependently bifurcate with its two ends clamped together by a bolt 149.

Projecting from the top of the lever arm 148 is a pivot coupling held by a bolt 151 and washer 152. Each of the pivot couplings 150, 193 are attached to an

eyebolt

153, 154 and the latter are connected together by a tie rod having its ends oppositely threaded and inserted in the correspondingly threaded sockets of the two couplings. Rotation of the threadedly engaged tie rod serves to draw together or separate the pair of coupled eye bolts according to the direction of rotation. Accordingly, with the coupling 193 located off-center to the vertical shaft 187, each rotation of the latter will laterally oscillate both the horizontal shaft 39 and its forward, bottom-supported upstanding post (35-38) as well as its distal workpiece 80, such ultimate movement being transverse to the workpiece. The arcuate extent of the stroke or oscillation of the horizontal shaft 39 can be varied by adjustment of either or both of the exposed length of the tie rod 155 and by the location (eccentricity) of the coupling 193 along the guideway 192.

It will be apparent, of course, that the flexible spindle 87 can be used to support either a lap or a workpiece, and the oscillating arm 50 will carry the other frictionally-engaging member of the pair.

I claim;

1. in a grinding and polishing device comprising a pair of endwise-aligned support members each adapted to have their adjacent ends moved in a different, closed, repetative path while terminally supporting a respective lap and workpiece in sliding frictional registration with each other:

the improvement wherein one of said support mem bers comprises an elongated, non-rotating, flexible, cylindrical spindle fixedly extending from a distal support to an aligned support end, and is rotatably embraced eccentrically, intermediate its length by first ring means, whereby said spindle may be flexed laterally upon rotation of said ring means so as to move the terminal support and in a generally annular path.

2. A device according to claim 1 wherein said first ring means are outwardly rotatably embraced eccentrically by second ring means, which latter are rotatable at a different speed from that of said first ring means.

3. A device according to claim 2 wherein said first and second ring means each comprise a tubular member spacedly separated by annular bearing means and each generally apically traversed by said spindle.

4. A device according to claim 3 wherein said first and second ring means are both contained within a generally dome-shaped flexible housing which sealingly engages said spindle intermediate said aligned support end and the embracing end of the first ring means, whereby said housing is also flexed by oscillation of the spindle.

5. A device according to claim 4 wherein said spindle is disposed upright and detachably supports said lap on its top, and said other support member is disposed to oscillate transverse thereto.

6. A grinding and polishing device comprising in combination:

rocker arm means carrying universal joint means for holding a workpiece suspended therefrom;

an upstanding flexible spindle fixedly mounted adjacent one end and at its other end supporting a lap in position for curvilinear sliding engagement with different speeds and for oscillating said rocker arms.

7. A device according to claim 6 which additionally includes a laterally flexible dome fixedly engaging said spindle around a circumferential area intermediate the lap and the inner housing.

8. A device according to claim 7 wherein said pair of nested housings are outwardly surrounded by a fixed housing which is traversed by said spindle, said outer housing being separated from the fixed housing and from the inner housing respectively by annular bearing means.

9. A device according to claim 6 wherein said pair of nested housings and said rocker arm means are all operated by pulley means from a common rotary motor.

10. A device according to claim 9 which includes amplitude adjustment means for said rocket arm means, and means for exerting selected pressure on the workpiece through said rocker arm means.

UNITED STATES PATENT OFFICE- CERTIFICATE OF CORRECTION Da ed January 1 197A Patent No. 5,782, OLFZ Invent0r(s) RAY HOWARD STRASBAUGH It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claim 1, next to the last line, "and" should read end Column I, line 57, "steam" should read stream Column 5, line-17, "of" should read or Signed and sealed this 13th day of' August 197 (SEAL) Attest MCCOY M. GIBSON, JR. (2. MARSHALL DANN Attesting Officer Commissioner of Patents UsCOMMv-Dc 60876-P69 w us. sovzmmzm' rnm'rmc OFfICl: yin (wan-3:4

F ORM PO-1050 (10-69)

Claims

1. In a grinding and polishing device comprising a pair of endwise-aligned support members each adapted to have their adjacent ends moved in a different, closed, repetative path while terminally supporting a respective lap and workpiece in sliding frictional registration with each other: the improvement wherein one of said support members comprises an elongated, non-rotating, flexible, cylindrical spindle fixedly extending from a distal support to an aligned support end, and is rotatably embraced eccentrically, intermediate its length by first ring means, whereby said spindle may be flexed laterally upon rotation of said ring means so as to move the terminal support and in a generally annular path.

6. A grinding and polishing device comprising in combination: rocker arm means carrying universal joint means for holding a workpiece suspended therefrom; an upstanding flexible spindle fixedly mounted adjacent one end and at its other end supporting a lap in position for curvilinear sliding engagement with said workpiece; a pair of nested housings surrounding and spaced successively outward from said spindle, the inner housing rotatably engaging the spindle eccentrically at a circumferential area intermediate its length and the outer housing rotatably engaging the inner housing eccentrically adjacent said area; and means for simultaneously rotating said housings at different speeds and for oscillating said rocker arms.