US2176154A

US2176154A - Lens grinding machine

Info

Publication number: US2176154A
Application number: US113684A
Authority: US
Inventors: Shannon Joseph
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-12-01
Filing date: 1936-12-01
Publication date: 1939-10-17
Anticipated expiration: 1956-10-17

Description

Oct. 17, 1939. J. SHANNON 2,176,154

LENS GRINDING MACHINE Filed Dec. 1,1936 4 sheets-sheet 1 ATTO R N EYS Oct. 17? 1939. Jl SHANNON 2,176,154

LENS GRINDING MACHINE Filed Dec. l, 1936 4 Sheets-Sheet 2 QZQQT 18 ,95K QE?? INVENTOR ATTORNEYS Oct. 17, 1939. SHANNON 2,176,154

LENS GRINDING MACHINE Filed Deo. l, 1936 4 Sheets-Sheet 3 In! all!! INVENTOR Mmes BY ATTORNEYS oct. 17, 1939. J. SHANNON 2,116,154

LENS GRINDING MACHINE Filed Dec. l, 1936 4 Sheets-Sheet 4 sa" foe @/ZQZ/Zofz INVENTOR gay@ 56, BY @4% ATTORNEYS Patented Oct. 17, 1939 UNlTED STATES PATENT oFFicE 3 Claims.

My invention relates to improvements in grinding and polishing machines for producing cylinder lenses.

In machines of this class, as usually constructed, a work support or lens holder and a grinding tool commonly called a lap member, are moved either relatively, or, one with respect to the other, to effect the grinding and polishing operation. The character and direction of move- Ll)v ments Varies in different makes of machines with more or less satisfactory results but within a limited range or eld of operation as regards the cylinder diopters which such machines are capable of grinding and polishing accurately on a lens. Moreover, in machines of this class known to me, vibration is excessive, particularly under high speed operation, and frequently results in inaccurately or imperfectly ground lenses.

Z Having the foregoing in mind, the primary object of my invention is to provide a high speed lens grinding and polishing machine having a wider range of operation than machines heretofore devised for this purpose and in which vibration has been reduced to a negligible degree to render the machine accurate in the high speed operation thereof.

Another object is to provide a machine of the class and for the purpose above set forth adapted 50 for simultaneously grinding and polishing a pair of lenses concave and convex,.respectively.

Still another object is to provide a high speed machine for simultaneously driving a lens holder and a lap member over a lap member and a lens 55 holder, respectively, each in different zig-zag paths and with related holders and lap members always in proper axial relation for accurate cylinder grinding.

Still another object is to provide for so-called L0 cap grinding and polishing lenses by movement of a lap member thereover, in a zig-zag path in co-axial relation to the lens and for oscillating the lens with a Variable throw to produce surfaces of different cylinder diopters on said lenses.

Other and subordinate objects are also comprehended by my invention, all of which, together with the exact nature of my improvements, will be understood as the following description proceeds and upon reference to the drawings accompanying and forming part of the specification.

In said drawings:

Figure 1 is a view in top plan of a machine embodying my improvements.

'tai

Figure 2 is a View in transverse section taken.

on theline 2 2 of Figure 1 looking in the direction indicated by the arrows.

Figure 3 is a fragmentary view of part of a pitman drive for the machine.

Figure 4 is a similar View of another similar 5 drive with which the machine is equipped.

Figure 5 is a view in transverse section taken on the line 5 5 of Figure 4 looking in the direction indicated by the arrows.

Figure 6 is a View in longitudinal section taken 10 on the line 6 6 of Figure 1 looking in the direction indicated by the arrows.

Figure 7 is a View in transverse section taken on the line 1 1 of Figure 1 looking in the direction indicated by the arrows.

Figure 8 is a similar View taken on the line 8 8 of Figure 1.

Figure 9 is a View in horizontal section taken on the line 9 9 of Figure 1 looking in the direction of the arrows.

Figure 10 is a similar view taken on the line l0 lll of Figure 1.

Figure 11 is another similar View taken on the line H II of Figure 1.

Figure l2 isV a detail View in top plan of a 25 reciprocatoryl carriage and an oscillating carriage thereon forming part of the drive mechanism of the machine.

Figure 13 is a fragmentary View in tcp plan of a sleeve member and a shaft forming part of the b reciprocatory carriage.

Figure 14 is a view in top plan-of a rocker arm forming part of the oscillating carriage.

Figure l5 is a view in transverse section taken on the line IE5-l5 of Figure l of a convex lens 3 driving unit.

Figure 16 is a similar view illustrating the operation of said unit.

Figure 17 is a fragmentary View in side elevation of a portion of said unit.

Figure 18 is a view in transverse section of a A cap grinding and polishing unit.

Figure 19 is a similar fragmentary View illustrating the parts of said unit in their normal position.

Figure 20 is a view in sideV elevation of the part shown in Figure 19;

Figure 2l is a detail view in section further illustrating the operation of the convex grinding unit. Y

Figure 22 is a similar view illustrating the corresponding position in the operation of the machine of the cap polishing and grinding unit.

Figure 23 andk 24 are detail views of bearingsY for said units. 55,

Figure 25 is a diagrammatic view illustrating the operation of the unit, and

Figure 26 is a similar View further illustrating the operation of the cap grinding unit.

Referring to the drawings by numerals, the illustrated embodiment of my invention comprises concave and convex grinding units I and 2 respectively, the former, a so-called cap grinding and polishing unit. The two units are arranged side by side on a base 3. The grinding unit I comprises a lens support 4, of the usual type, mounted on said base 3, in a manner presently described in detail, and a lap member 5 surmounting the support 4. The support 4 is shown with a lens 5 cemented therein according to the usual way of mounting the lens in the support member The grinding unit 2 comprises a lap member 1 mounted n the base 3, in a manner presently described, and a lens support or carrier 8 surmounting the lap member 1. The lens 8' is cemented to the support or carrier 8 as shown in Figure 21.

The lap member of the unit I and the lens carrier 3 of the unit 2 are mounted in separate frames 9 and le, respectively, disposed side by side in parallel relation and each comprising a rectangular head part II and a rearwardly extending shank part I2. The manner in which the lap member 5 and the lens carrier 8 are mounted in their respective frames, 3 and I8, will presently be referred to in detail. The frames 9 and IE! are mounted on a horizontally reciprocating carriage I3 for reciprocation in unison. The carriage I3 comprises a sleeve I4 having a rearwardly disposed V-shaped extension I5. The sleeve I4 is slidably mounted, on bearing bosses I6, on a horizontally disposed shaft I1 xed at its opposite ends in brackets I8 arising from the base 3. Set collars I9 on said shaft I1 and set screws 20 in the brackets I8 secure said shaft in position in said brackets. The shaft I1 is bored axially and transversely, as at 2| and 22 respectively, for the introduction of oil through said shaft into the sleeve I4. The extension I5 of the carriage I3 is pivotally mounted by means of a cone bearing stud 23, on a link 24 opposed to the sleeve I4 and pivotally mounted at its opposite ends on a pair of oppositely disposed

rocker arms

25 and 26 pivoted on the base 3 and a bearing bracket 21, respectively, as by pivot bolts 28. The arrangement of the link 24 and the

rocker arms

25 and 28 is such that the link 24 moves substantially parallel with the sleeve I4.

The carriage I3 is driven from a main drive shaft 29 journaled adjacent its opposite ends, parallel with the shaft I1, in bearing brackets 3U secured to the base 3 in any suitable manner. The main shaft 29 is driven through the medium of a belt and pulley drive, indicated at 3I and 32, by a suitable motor (not shown). A worm 33 fast on the main drive shaft 29 meshes with a worm wheel 34 fast on a short shaft 35 journaled in bearings 35 on the base 3. The short shaft 35 is operatively connected to the carriage I3 by means of a pitman drive comprising a disc 31 fast on said shaft and a pitman rod 38 connected to a lug 39 on the sleeve I4. The connection between the pitman rod 38 and disc 31, as shown in Figures 3 and 5, comprises an eccentric 4Q adjustable in a strap 4I for varying the throw of the rod 31, as will be understood.

The frames 9 and I!! are mounted on the carriage I3 for oscillation thereon transversely of their paths of reciprocation by said carriage, in curved paths, respectively, and in opposite directions relative to each other. For this purpose the shank parts I2 of said frames are mounted, by means presently described, on a horizontally disposed oscillating carriage 42. The oscillating carriage 42 comprises a pair of V-shaped yokes 43 pivoted, as at 44, upon the opposite ends of a pair of subjacent parallel links 45 which in turn are pivoted intermediate their ends, as at 46, on a rocker 41. The rocker 41 is pivotally mounted on the carriage I3 between a cone bearing stud 48 on the sleeve I4 and the beforementioned cone bearing stud 23, the arrangement of the rocker 41 being such that the oscillating carriage 42 has a compensating rocking movement vertically about an axis at a right angle to its axes of oscillation.

The carriage 42 is oscillated by means of a yoke member 48 pivotally mounted, as at 50, on the base 3 for vertical rocking movement in bearings 5I, on the base 3, and to which the main drive shaft 29 is operatively connected by means of a pitman drive including a disc 52 fast on said shaft and a connecting rod 53 extending between said disc and the yoke. A second yoke member 54 is pivotally mounted, as at 55, on the yoke 49 for vertical rocking movement with the yoke 49 and for independent rocking movement laterally about an axis at a right angle to the common axis of movement of said yoke. The yoke 54 is operatively connected to one of the links 45 of the carriage 42 by means of a rod 55 extending from said link and a ball and socket connection 56 between said rod and the yoke 54. The socket part of the connection 56 comprises a section 51 adjustable in the yoke 54 by means of a set screw 58 to take up wear in the connection and for coupling said connection together. As will be seen, the carriage 42 oscillates arcuately during its reciprocation by the carriage I3. The yoke 54 operates in its independent movement to compensate for such reciprocation during oscillation of said carriage 42. In this connection it is to be noted that the axis of movement of the rocker 41 provides for compensating movement of the carriage 42 under the throw of the yoke 54 during such independent movement thereof.

The lap member 5 and the lens carrier 8 are mounted in the heads II of their respective frames, 9 and I0, for swinging movement in the general direction of oscillation of said frames and as follows. The head I I of each each frame, 9 and I U, is provided on its under side with a pair of opposed needle bearings 59. Co-operating with the bearings 59 of each head II is a yoke bar 60 having angular ends 6I adapted to seat against said bearings and rock thereon. The lens carrier 8, or the lap member 5, as the case may be, is secured to the under side of said yoke bar intermediate its ends. In the case of the lens carrier 8 a stud 62 on said carrier extends upwardly through the related yoke bar 60 and is adjustably secured therein by nuts 63. The lap member 5 is formed integrally with its related yoke bar 60. A tensioned spring 64 connected with the front of each head II, as at 65, and to the base 3, as at 66, yieldingly retains the lenses 6 and 8 and the lap members 5 and 1 in engagement, shown in Figures 15 and 20, so that under oscillation of the frames 8 and I0 the lap member 5 and the lens 8' are caused to move in their respective frames 9 and I0 concentrically of the lens 5 and the lap 1, respectively.

The frames 9 and I0 are mounted in their respective yokes 43 for movement of each about right-angularly related axes and as follows. The Shanks I2 are supported in their respective yokes 43 by means of bearing brackets 61. The bearing brackets 6l are each pivotally mounted by cone bearings 68 in their respective yoke 43 for vertical rocking movement about a horizontal axis transverse to the direction of oscillation of said yoke. The Shanks I2 of the frames 9 and l are pivotally mounted by similar bearings 69 in their respective brackets 61 for lateral movement of the frames 9 and I8 about horizontal axes extending substantially in the direction of the oscillation of said frames. The cone bearings 68 and 89 are each adjustable to take up wear and removable for replacement of parts. By virtue of the described means of mounting the frames 9 and I8 in the yokes 43, the lenses 6 and 8 and the lap members 5 and l, under the action of the springs 64, are maintained in axial relation during reciprocation of the frames I2 by the carriage I3.

The lap member is provided with an aperture 'lll therein for introducing the usual abrasive and grinding material into said lap member without lifting the lap member from 01T the lens 6.

In the case of the cap grinding and polishing unit l, the lens support or carrier 4 is mounted for oscillation in the general direction of oscillation of the lap member 5 and with a variable throw. For this purpose the support 4, as shown in Figure 1l, is mounted for vertical adjustment on a horizontally disposed rocking yoke 1| mounted to rock vertically at its opposite ends lupon spherical bearings 72 on bearing brackets 'I3 upstanding from the base 3. A pair of tension springs 14 connected at their opposite ends to the yoke 'H and to the base 3, as at 15 and T6, respectively, tension said yoke ll against movement from a central position. The mounting for the support or carrier 4 on said yoke 'Il comprises a shank Il depending from said support 4 and slidably mounted in a sleeve 'i8 on said yoke H for vertical adjustment of said support to different set positions. A set screw 19 provides for locking the shank 11 and support 4 in different set positions. The yoke 'H is rocked in opposite directions respectively by a pitman drive 80 comprising a pair of reduction gears 8| and 82, the former fast on the drive shaft 29 and the latter mounted in a bearing bracket 83 on the base 3. A pitman rod 84 connected at its opposite ends to a crank pin 85 on the gear 82 and a crank arm 36 on the yoke 1I operatively connects said gearing to said yoke. The oscillating support 4 provides for moving the lens 6 thereon into the lap member 5 so that uniform polishing may be obtained in all meridians of a cylinder. By adjusting the support 4 to different set positions, the throw of the lens thereon may be varied in accordance with the cylinder diopters to be polished. The shank Tl is provided with the graduations 81, Figure 18, which may be appropriately designated to indicate proper settings for the polishing of different cylinder diopters.

From the foregoing it will be manifest that my invention provides a mechanism for moving a lens carrier and a lap, relative to a lap and a lens carrier, with both a reciprocating stroke and an oscillating stroke transverse to the line of movement of the reciprocating stroke, the reciprocating stroke being longer than the oscillating stroke. Preferably the relative timing of the oscillating and reciprocatory carriage drives is approximately four to one, so that four oscillating strokes are effected to one reciprocating stroke'. The result of this is that the lens carrier and the lap are moved across their related lens carrier and lap in different zig-zag paths, as illustrated in Figures 25 and 26. The short strokes, being in opposed curves, neutralize the vibration so that the machine is easy running at high speed. By adjusting the oscillating support 4, the stroke on this side of the machine may be lengthened or shortened, in accordance with different operating requirements. In this connection it is to be noted that the frames 9 and I!) are always maintained parallel lengthwise, regardless of the size of the oscillating strokes on different sides of the machine, and the lens and the lap carried by said frames prevented from turning axially, which features provides for a high degree of lap accuracy under all conditions.

The foregoing is a detailed description of a preferred embodiment of my invention and it is believed that its operation and advantages will be clear therefrom without further explanation.

It is to be understood, however, that the present disclosure is illustrative rather than restrictive and that right is herein reserved to modifications of details described, and relations of parts, falling within the scope of the claims appended hereto.

What I claim is:

l. A lens grinding and polishing machine comprising a base, a lens support, a lap member, a frame surmounting said support, a second frame surmounting said member, means for reciprocatir said frames, a pair of V-shaped yokes connected one to each frame, means connecting said yokes together whereby to effect simultaneous oscillation thereof, and means connected to at least one of said yokes to effect oscillation of said yokes.

2. A lens grinding and polishing machine comprising a base, a lens support, a lap member, a frame surmounting said support, .a second frame surmounting said member, means for reciprocating said frames, a pair of V-shaped yokes connected one to each frame, means connecting said yokes together whereby to eifect simultaneous oscillation thereof, and operating means connected to said yokes in such a manner that the degree of oscillations may be varied relative to the reciprocation of said frames.

3. A lens grinding and polishing machine comprising a base, a lens support, a lap member, a frame surmounting said support, a second frame surmounting said member, means for reciprocating said frames, a pair of V-shaped yokes connected one to each frame, means connected to one of said yokes for oscillation thereof, and means connected to the convergent ends of said yokes whereby to efectvoscillation of the other of said yokes coactive with the oscillation of said one yoke, the oscillation of said other yoke being reverse from the oscillation of said one yoke.

JOSEPH SHANNON.