US2493206A - Lens grinding and polishing machine - Google Patents

Description

Jan. 3, 1950 Filed June 2'7, 1945 P. OKEY 2,493,206

LENS GRINDING AND POLISHING MACHINE 5 Sheets-Sheet 3 I73 I65 1 222 w M 149147 150 I463!- 21 2a 33 15/ a 35 :5 /97 77, u F v so $4 84 2 6 86 7 U as $6 0 0 v @0 V 72 79 D '54 V (7 5 1 z 1 56 V e v n m N w 48 Z F '3 V m 31 38 a? r 6 23 38 37 INVENTOR Pew fife J M4,

ATTORNEY P. OKEY 2,493,206 LENS GRINDING AND POLISHING mama? 1] 11 Jan. 3, 1950 5 SheetsSheet 4 Filed June 27, 1945 INVENTOR Jan. 3, 1950 P, QKEY 285 GRINDING AND POLISHING MACHINE Filed June 27, 1,945 5 Sheets-Sheet 5 38 I05 l n:

I00 99 1 1/ HI] I INVENTOR q? 0/ V BY I 7.

TTCDRNEY Patented Jan. 3, 1950 LENS GRINDING AND POLISHING MACHINE Perry Okey, Columbus, Ohio, assignor to Perry- -Lowell & 00., Columbus, Ohio,

a partnership Application June 27, 1945, Serial No. 601,749

9 Claims. I

The present invention relates to a lens making machine and more particularly to a machine for abrading or grinding a plurality of lenses simultaneously, in which machine there is provided a tion to provide a valve which is selectively operated either to elect relative movement'between the abrading element and the lens element or to effect the station changing function, control p u y f w p rf rmin stations, each pera mechanism being provided for preventing one forming a slightly different function upon the of the hydraulic mechanisms operating premala th m chin ein pro ided f r pr ere turely so that the proper sequence of functions sively moving the lenses from station to station. t b performed is assured one f the bje s of the P'reSent invention is In other words, it is another object of the presto provide a machine which will simultaneously m; i ti t interconnect hydraulic m abrade the plurality of lenses at different work anism m such a manner t t parts actuated by performing stations and which onl a predeterone of the pistonsmust be in a predetermined mined amount of material is removed at each posmon befm-e t other hydraulic mechanism station although the time for removing the decan perform t fun tio sired amount may be greater at one station than it In carrying t certain of t foregoing the other. In carrying out this object, it is a j t a table is provided having a plurality f further object of the present invention to pro performing t t and t table fro vide for relative rotation by the abrading element t t time, t t part of a t To and the lens element and to bias one toward complish this, there is provided a hydraulically the other but to limit the extent of the biasing 2i) operated piston and a connected t the movement so that after the necessary abrading table by a clutch w the piston moves in operation is performed, the relative rotation may one direction the table is advanced a part of & continue without ifurther removal of material. g and 1 m u retained in t new p051- In carrying out the foregoing object, it is a on while t piston is retracted. further object or the present invention to pro- A still further object of the present invention vide a plurality of supports, one for the abradis to impede the speed of the piston as it mg element and one for the lens which proaches the end of its stroke so as to prevent ports are moved toward one another during the the momentum of the moving table from travel abrading operation, and more particularly, one mg beyond the station at which the Succeeding of the supports being in the form of a lever in work is to be performed which the pivot for the lever is disposed m a A still further object of the present invention plane intersecting, substantially at right angles, is to prevent the now of actuating fluid to the the axis of the rotating element carried by the cylinder provided for accomplishingxthe rotation other Support at the engagmg surfaces of the of the table until the table has been moved, in two glements an axial direction, to a predetermined distance, It is a further obJect of the present invention whereby the abradingand lens elements are to provide a signal for the .operator indicating pletely Separated fidm one another prior to the when an of the abrading functions being persucceeding partial rotation of the table to the formed, are completed. is next station In g gi fi 53 x gg gg gggfgfi g 40 Further objects and advantages of the present ur er 0 3e invention will be apparent from the following utilize the stops, WhlCh limit the extent of move t ment of the element being abraded and the lens descnption reference being had to he accom' element toward one another, as an electrical panymg drawings wherein a Preferred form contact in a circuit, the circuit being so arranged embodiment the mventbn is clearly shownas to give the signal after each of the separate the drawings: abrading functions are completed. 1 is a p P a Vi w Showing a machine It is still another object of the present invenhaving fi e a radins stations and one load station to utilize a pressure responsive system, such as a hydraulic system, to eilect certain relative 2 15 a 88013101181 V w taken on line 2-2 movement between the abrading element and f the lens element, and to efiect the shifting of Fig. 3 is a fragmentary sectional view taken the lens from station to station by hydraulic on line 3-3 of Fig. 1; mechanism, and in carrying out this object, it Fig. 4 is a fragmentary sectional view taken is a more specific object of the present invenon line t-t oi Fig.2;

Fig. 5 is a fragmentary sectional view taken on line 5-5 of Fig. 1;

Fig. 6 is a view similar to Fig. 5 but showing certain elements in different positions;

Fig. 7 is a diagrammatic view of a hydraulic system showing the position of the valves after the completion of the partial rotation of the table, but before the piston is retracted;

Fig. 8 is another view of the hydraulic system showing the position of the valves just after the work table has been moved into abrading position;

Fig. 9 is a fragmentary sectional view taken on line 9-9 of Fig. 2;

Fig. 10 is a wiring diagram of the motor for a driving the spindles which carry the lens;

Fig. 11 is a wiring diagram of the signal circult;

Fig. 12 is a wiring diagram of the circuit for the electric motors which drive the abrading elements;

Fig. 13 is a fragmentary sectional view taken on line l3-l3 of Fig. 1;

Fig. 14 is a fragmentary view looking in the direction of arrow l4 in Fig. 3;

Fig. 15 is a perspective view of a lens blank showing a near vision surface and distant vision surface: and

Fig. 16 shows the finished blank severed for the purpose of making two bifocal lens.

In the drawings, attention is specifically directed to Fig. 3. One of the abrading elements is shown at 20 driven by a motor 2|. The abrading element is in the form of a wheel 20 and is shown in an abrading position with a lens blank 23 suitably secured to a lens carrier 24 which, in turn, is carried by a spindle 25. Spindle 25 is driven by a gear 26 which, in turn, is connected by other gearing 21 to a motor 29. During the abrading operation. both motors 2| and 29 are operated so that rotating movements are imparted to the abrading wheel 20 and the lens blank 23, simultaneously. The directions of rotations of a wheel 20 and lens blank 23 may be the same or counter to one another but in either case or under either condition, abrading wheel 20 rotates at a much higher speed than the lens blank.

Motor 2| is mounted on an arm 3| of a lever 32 pivoted on pin 33. The other arm 34 of lever 32 is arranged to engage a stop 35. Due to the weight of the motor 2|, the lever 32 tends to move in a counter-clockwise direction. as viewed in Fig. 3, and the abrading operation will continue until the lever 32 is brought to rest upon engagement with the stop 35.

By reference to Fig. 1, it will be apparent that six separate stations are provided. These stations are the loading station A and work stations B, C, D, E and F. The machine herein shown is used in the manufacture of bifocal lens which are circular in plan and later severed in two pieces to provide two semi-circular biforcal lenses. The lens blank 23 is shown in Fig. 15, having a near vision field 31 and a distant field 38. The lens blank 23 and the lens blank holder 24 are placed on the spindle 25 at the load station A during the time that the abrading operations are taking place at stations B to F, inclusive. After the specific function is performed at each of the work stations, as indicated to the operator by a signal light, the lens blanks will be advanced, in a clockwise direction, one-sixth of a revolution where the next operation will be performed on the lens blank. Rough grindings are effected on the distant vision surface 38 at stations B and 4 C. At station D the last grinding or fine grinding is effected for surface 38. Rough grinding of near vision surface 31 is effected at station E. Fine grinding of surface 31 is effected at station F.

Referring now specifically to Fig. 2, there is shown a main base 40 including a bottom wall 4| and a cylindrical side wall 42. The bottom wall 4| is provided with reinforcing webs 43 and the top side of the bottom carries a cylindrical standard 45 having a flangedbase 45 secured to the bottom 4| by bolts 41. A cylinder 48 surrounds but is spaced from the standard 45, thus forming a fluid chamber 49 therebetween. This cylinder 48 is secured to the base by bolts 50. The top of the cylinder is provided with a circular groove 52 which is filled with ball bearings 53. A hub 54 surrounds the standard 45. the standard 45 functioning as an axle for the hub.

The hub 54 is provided with an extension in a form of a table 56 and which is adapted, at times, to rest upon the ball bearings 53 for the ready rotation of the hub. The lower part 51 of the hub 54 telescopes into the chamber 49 between the cylinder 48 and the axle 45 and at the lower end thereof is provided with a fluid packing 58.

When liquid is admitted to the chamber 49 through the pipe 60, the piston formed by the part 5'! and the integral hub 54 and table 56 will be raised. As will appear more in detail hereinafter, this raising of the hub is utilized to bring the lens blanks 23 into contact with the abrading wheels 20.

From Fig. 3, it will be seen that the motor 29 which drives the spindles 25 is carried by the table 56 and therefore is translated to six different positions. The gearings for driving the spindles 25 are also translated with the hub 54 and table 56.

Referring again to Fig. 2, it will be seen that the upper part of the hub 54 carries an upper table 52 which is secured in position by bolts 63. Upper table 52 carries a plurality of bearings 64 for gears 65 which, through idler gears 65, drive the gears 26 on the spindles 25. The gears are driven by a pinion 86 from the motor 29. Two of the bearings 54 are shown in detail in Fig. 2.

In the present invention, the motor 29 is shown of the three-phase type which is connected by three spring fingers 69 to anyone of six sets of three contacts 10 in an electric circuit. These sets of contacts 10 are carried on the underside of an inwardly extending circular fiange ll of a circular trough 12. The sets of contacts 10 are spaced 60 from one another. When the three fingers 69 engage all three contacts of any set of contacts 10, the motor 29 will be started and the spindles 25 will be rotated. From this, it will be seen that starting and stopping of ".e rotation of spindles 25 is controlled by the raising and lowering of the hub 54, that is, when the hub 54 is raised to a predetermined level, the spindles will start to turn, and, when thehub is lowered, rotation of spindles stops.

The position of the hub 54 is also closely and accurately indexed by the raising of the hub. For this purpose, there are provided a plurality of upwardly extending tapered pins 13 on the top of table 62. Preferably six of these pins are provided, arranged in a circle and disposed 60 from one another; these pins are arranged to be received simultaneously by six sockets 14 which are also tapered and formed in the platform -l5. Platform I5 is secured to the standard 45 by a series of bolts 16. The pins 13 and the sockets 14 are formed of hardened steel and are ground to fitting relation after assembly on the respective table 62 and platform 15. The tapered pins I3 and sockets I4 insure the proper location of table 62 when the table has been moved to its extreme upper position. The tops of these sockets 14 are closed by caps 11.

As will be seen from Fig. 12, motors 2i are connected in parallel through a three-pole switch '10 and this switch is opened and closed by a push rod 19 (see Fig. 8) which extendsthrough and is guided by platform 15 and which is raised and lowered for performing the switch operation. by the table 62. From the foregoing, it will be seen that when the blanks 23 are brought into abrading relation with the abrading wheels 20, spindle driving motor 29 will be in operation and the abrading motors will be also in operation.

Each lens blank 23 is adiustably secured for rotation at a predetermined height. The vertical adjusting mechanism tor the spindle height is shown in Fig. 3 and the spindle can be shifted axially, that is vertically, by a hand wheel 30. Six sleeves BI are carried by the periphery of the table 62 and each or the lower parts of these sleeves isthreaded attZ to receive the threaded hand wheel 80. The hand wheel is so connected to a sleeve as, disposed in the hub at, so as to raise and lower the sleeve 0%. The spindle 25 is carried by the bearings 05, suitable shoulders 86 being'provided on the spindle 25 which cooperate with the inner races and an interposed sleeve 08 to relatively fix the axial position of the spindle 25 with respect to the sleeve 86. Thus. by turning the wheel 90, the spindle 28- can be moved axially relative to the table 32. The gears 21 are made sufliciently wide to take care of all normal adjustments effectable by the wheels 00.

The height of the lens blank 23 may be determined by a gauge 90, see Fig. 5. This gauge is carried by a lever 9i pivoted at 92 to a standard 93 which, in turn, is carried by the platform 15. After the lens blank and holder assembly is placed in position at the loading station, the lever 3| is swung downwardly by the operator by handle 95 and if the lens blank is not at the proper height, the hand wheel 00 is turned in one direction or the other in order to bring the top surface of the lens blank at the proper height.

When the work at each specific station has been completed, the fluid is released from the chamber 49 and the hub 54 and tables 55 and 62 carried thereby are lowered until the entire hub section 54 rests upon the balls 53. Of course at this time, the circuit to the motor 29 is interrupted at and the circuit to the motors 2| are interrupted at 18. Switch 18 is of the type which is normally biased to open circuit position by a spring and when the push rod 19, therefor, has released the switch, the switch automatically opens.

The next operation in the sequence is to rotate the table 62, 60.. This rotation is effected by a ram 99, clutch 99 and pins I00. Six of these pins depend from the table 56 and are arranged in a circle concentrically with the axle 45. Ram 98 is actuated by a piston I02 disposed in the cylinder I03. The clutch 99, in the form of a hook I04, is pivoted on the ram 00 at I05. This hook is normally urged inwardly by a spring I00. In Fig. 9, the ram. 9% is shown in its retracted position.

When fluid is admitted to the cylinder I03, the ram as and hook I061 will be moved to the right. The hook Itt will engage one or the pins lit and upon one stroke will cause tables 06 and 62 to be rotated 60". The flow of fluid through the cylinder I03 is through a valve I01 and this valve is not opened until the hub 54 has reached substantially its lowermost position. The valve I0! is actuated by a lever I08 pivoted at I09. The end of the lever carries a roller H0 which is engaged by the bottom side of the table 56 when the table 56 reaches substantially its lowermost position.

The hub 54 is yieldingly retained in position into which it is moved by the hook I04. The mechanism for accomplishing this is shown in Fig. 9 and comprises a bell crank lever H2 which is pivoted at II3. Lever II2 includes an arm II4 for carrying two spaced rollers II5 which are arranged to substantially straddle one of the pins I00. These rollers are yieldingly urged against the pins I00 by a spring H6. When the piston I02 and the ram 98 are retracted, the bell crank lever m retains the hub 5a in its new position. The left end of the hook I04 is provided with a camming surface II! which engages the pin I00 then lying in its path and therefore, by compressing spring I06 permits the hook to slide beyond said pin I00 and after the apex of cam Ill passes the pin I00, the spring expands, causing the hook I00 to come to rest in the position shown in Fig. 9.

The movement of the hub St is decelerated toward the end of its movement and this is accomplished by impeding the flow of fluid to the cylinder I03 as the piston I02 approaches the end of its stroke. Referring to Figs. 7 and 8, it will be seen that the piston carries a valve stem IIQ which in turn carries a tapering valve I20 which controls the flow of fluid to the cylinder I03 through the valve seat I2I. Valve seat IZI is interposed between a valve chamber I22 and cylinder I03. The tapering valve I20 decreases the flow of fluid to the cylinder I03 as the piston I02 approaches the end of the stroke. In this manner, the deceleration is such as to substantially eliminate momentum of the moving mass, which momentum would carry the table 55 beyond the stops predetermined by the rollers H5 and pins Pins I00 also open a valve I23 and retain the valve open as long as the hub 5 is in the position in which the grinding operation is to take place. A spring I24 normally urges valve I23 to the closed position. However, each of the pins I00 is arranged to open the valve through the linkage indicated at I25. Valve I23 is arranged to control the flow of fluid from the pump and to and from the cylinder 49.

Thus valve I23 prevents flow of liquid to the chamber 49 except when the table 56 is So located -that the pins I00 open the valve I23 (i. e. s0 located that when raised the pins l3 will register with the holes It and the lens carriers 20 will be properly positioned relative to the abrading wheels 20).

Referring now to the diagrammatic view, Fig. 7, of a hydraulic system, which shows the position of the valves and mechanism just after the clutch 93 has moved the hub but before the clutch has been retracted, the pump is shows at I26 which is arranged to withdraw fluid, preferably liquid, from the reservoir ill by pipe I28 and force the fluid into a pipe I29. Fluid is returned to the reservoir I27 through a drain I3I. A high pressure relief valve I32 is interposed between pipes I29 and Isl to prevent the building of excessive pressure. A hand operated valve I3 6; determines the course of flow ofthe high pressure fluid. As shown in Fig. 7, the valve I34 connects the cylinder I 03 with the pump through pipe I29, valve passage I35, pipe I39, valve I01 and pipe I31. Fluid has been drained from the right of piston I02 by pipes I38, I39, valve passage I40 and drain I3I. It will be observed that valves I01 and I23 are being held open due to the lowered position of the table 56 and by one of the pins I00. Now when it is desirable to raise the table 52 so as to bring the work into abrading relation with the wheels 20, the hand valve I34 is shifted to the position shown in Fig. 8 so that valve passage I40 connects the high pressure pipe I29 with the pipe I39 causing fluid under pressure to enter the main cylinder chamber 49 and raise the piston 51 carrying the hub 54 and tables 62 and 50. Liquid under high pressure will also flow from pipe I39 through pipe I38 into the cylinder I03 to the right of piston I02, thus causing the clutch to be retracted and moved to the position shown in Fig. 9 so that the clutch will be conditioned for turning the hub 54 on the next succeeding operation. It will be observed from Fig. 2 that the valve I01 is closed substantially immediately after the table 55 starts to rise.

' A pipe I42 is connected with pipe I31. This pipe I42 carries a restrictor I43 which in turn is connected by a pipe I44 to the reservoir I21. The purpose of the pipes I31 and I44 is to drain the left side of the cylinder I03 after valve I01 is closed; the restricted passage I45 in restrictor I43 limits the flow therethrough so that the clutch returns in a smooth manner. However, the primarv purpose of the restrictor is to prevent the short circuiting of the fluid from the pump to drain at the time it is desirable to'move the piston I02 to the right. The resistance of the restrictor is such that it drains considerably less fluid than that pumped by the pump whereby, when the pump is operating and the valve I01 is open and the valve I34 is in the position shown in Fig. 7, the piston I02 will be moved with a determined force to the right.

After all of the grinding operations have been completed at the specific stations, it is necessary to shift the work to the next succeeding station. To accomplish this, it is necessary first to lower the blanks from the abrading wheels 20. To accomplish this. the hand operated valve I34 is shifted from the position shown in Fig. 8 to the position shown in Fig. '7. At this time the valve I01 is still closed. However, valve I23 is still open by reason of the position of the pin I00. Valve I23 remains open because the pin I merely moves vertically. Fluid drains from cylinder chamber 49 through pipe 60, valve I23, pipe I39, valve passage I40 and pipe I3I. The weight of the tables, hub, etc. forces the liquid to drain. Just before the table and other lowered parts reach their lowermost position, roller IIO of valve I01 will be engaged by the underside of table 56 to open valve I01 and, since the high pressure side of the pump is connected, through the passage I35 and valve I01. to the left side of the piston I02, the piston and the ram 98 will be moved to the right causing hook I04 to rotate the tables and the parts carried thereby a one-sixth turn. It is to be observed that immediately after the tables start to lower, as previously described, the circuit to the motor 29 will be interrupted at switch 69 and the circuits to the motors 2I will be interrupted by the switch 18. After the ram moves the tables a one-sixth turn, the tables will come to a rest because valve I20 is closed upon valve seat HI and one of the pins I00 is detained by the rollers II 5. Then the operator shifts the hand operated valve to the position shown in Fig. 8 to cause the elevating of the tables, as previously described, with the accompanying closing of switches 99, and 19 to start all of the motors.

As will later be explained more fully, cooling liquid is supplied to the lens blanks being ground and to the abrading wheel grinding the lens during the abrading operation. This liquid is thrown centrifugally from the blanks and the abrading wheels. Means are provided to prevent this cooling fluid from being scattered or thrown from the machine and to prevent it from escaping through the bearings for the spindles. A casting I40 partially surrounds each of the spindles and lens carriers. Each casting I46 has a circular bottom section I41 which entirely surrounds the associated spindle 25. Each casting I46 is also provided on the inward side of the spindle with a semi-circular upwardly extending section I41a. The circular bottom section I41 is secured to the table 62 by means of screws. A removable semicircular section I50 complements the section I4'Ia so that the sections I41, I41a and I50 form a casing for substantially enclosing the lens blank carrier 24. The removable section I50 is provided with a handle I5I, for removing that portion of the casing when removing ground lens and inserting lens blanks to be ground. It will be noted from the left hand side of Figure 15 that the removable section I50 at its bottom edge rests upon the, top of the table 62 inside of the circular lower portion I41 of the casting I49. The casing I46 formed by the portions I41, I41a and I50 is open at the top as shown at I49 so that the lower part of the motor shaft and the abrading wheel 29 may during the abrading operation extend down through the opening I49 and contact with the lens blank. Thus the casing I40 formed by the portion I41, the portion I41a and the portion I50 confines the flow of the liquid. The liquid after striking the inside walls of the casing I46 drops down into a basin which is formed by the circular mall I 41. This basin is designated in Figure 3 as During the abrading operation, the operator places a lens carrier 24 carrying an unground blank on the spindle 25 at station A, sets the height of the top of the blank by manipulating the wheel 80, checks the same by the gauge 90. After completing this operation, casing section I50 is placed about the lens blank. The gauge is then swung manually out of contacting position with the lens blank 23 by the handle and the lever 91 then rests upon a spring pressed plunger I52, the spring, not shown, being carried within the casing I53, the purpose of the spring being merely to absorb the shock of the backward movement of the lever 91.

In the event that the operator fails to move the gauge from the position shown in Fig. 5 to the position shown in Fig. 6, means is operated automatically to effect this movement upon the upward movement of the table 62. When the lever 91 is in the position shown in Fig. 5, the center of gravity thereof is to the left of the pivot pin 92. One end of a spring I56 is fastened to the platform 15 and the other end is fastened to a link I51. Link I51 hasa reduced portion I58 which fits loosely within a hole I60 in the platform 15 and extends below the platform 15 and is arranged to be actuated by the table 62. This link I51 has a longitudinal slot I8I therein which receives a pin I82 secured to the lever 91. Pin I 82 is free to move in the slot I6I when'the link I51 is in the position shown in Fig. 5. However, as soon as the table 62 is lowered, the spring I56-and gravity will force the link I51 downwardly pulling the pin I82 downwardly so as to tilt lever 91 to the position shown in Fig. 6 whereby, the casing sections will not strike the gauge when they are moved by the next turning of the table.

By the arrangement herein shown, any desired contact pressure can be maintained by the abrading wheels 20 and the lens blank and when desirable, this pressure can be reduced to substantially zero. As previously stated, the motors 2| are pivotally mounted and the weight is distributed so that the lever 32 tends to move in a counter-clockwise direction as viewed in Fig. 3. The degree of pressure can be adjused by varying the tension of supporting springs I65. These springs are arranged in pairs, one end of each being connected to the arm 3I and the other end being connected to a turn buckle I55 which in turn is connected by a rod I61 to a bracket I58. This bracket I68 is carried by a post I59 which is threaded into the top of platform 15 at I10. Thus, it will be seen that by turning the turn buckles I68 on the threaded rod I61, any desired pressure can be maintained between the abrading wheel 20 and the surface of the lens blank.

The angular relationship of the axes of each of the abrading elements 20 and each of the spindles 25 can be varied and held in adjusted position. This is accomplished by shifting each of the axes of the motors 2!. The motor shaft I12 of each of the motors H is carried in a sleeve type bearing I13 which, in turn, is secured in a sleeve I14. A circular flange I15 is formed integrally with and projects from the side of the sleeve I14. A narrow hub I15 extends from the side of the flange I15 and the hub and the flange are concentrically drilled and threaded to receive a bolt I18. The forward end of the arm III is provided with a recess I19 which receives the hub I16, and, a hole I88 is drilled concentrically with the recess for receiving the bolt I18. When the bolt is drawn tightly, the sleeve I14 is clamped in position on the arm 3i. A washer IBI is interposed between the bolt head and the arm. The top side of the end of arm 3I is bifurcated, the furcations being shown at I83 and a finger I84, formed integrally with the sleeve I14, extends between the furcations I83. Each of the furcations is threaded to receive screws I85. Each of these screws extend through one of the furcations and the ends of the screws are arranged to engage the finger I84, one on one side of. the finger and one on the other. To adjust the axis of the motor 2 I, the bolt I18 is loosened and the screws I85 are manipulated to move the finger to cause the rotation of the sleeve I14 and likewise the motor about the bolt I18. The bolt I18 is then tightened to clamp the sleeve in adjusted position.

An index line I88 is formed on the extreme forward end of the flange I15 and index lines I81 are formed on the extreme forward end of the arm 3I. After the axis of the shaft H2 is shifted to the desired position so as to provide the proper curvature of the surface of the lens being ground, the relative position of the line I88 with respect to the lines I81 is recorded for the purpose of reshifting to this exact position in the event that it is desirable to return to the same curvature after the axis of the shaft I12 has 10 v I been shifted for abrading another lens of a difierent curvature. I

The height of the abrading wheel 29 is adjusted by shifting the motor vertically in the sleeve I14.

For this purpose, there is provided an ear I88 on the lower part of the motor housing and an ear I89 on the sleeve I14. A bolt I98 is threaded into the. ear I88 and freely passes through the ear I89 on the sleeve I14. Adjusting nuts I9I are disposed on the opposite sides of the ear I89 and, when clamped against the ear, hold the .ear I89 in an adjusted position. To adjust the height of the abrading wheel 20, the positions of the nuts are shifted. For example, to raise the wheel 20, the top nut is loosened and the bottom nut is turned so as to slide the sleeve I14 upwardly. When the desired height is reached, the top nut is drawn tightly onto the ear I89.

It is also necessary to shift the axis of the abrading wheel 2|] horizontally in order to define the relative widths of the vision field 31 and the distant field 38. Although the positions of the arms 3I are shown in which the abrading of the lens blanks take place inwardly of the axes of the lens blanks, it is desirable, at times, to cause the abrading by the wheels 28 to take place outwardly of the axes of the lens blank. This shiftmg is accomplished by shifting the pivot pin 33 for the lever 32. The pivot pin 33 is carried by a bracket I92 including base I96 having a slot I95 which extends longitudinally of the lever 32. The bracket is slid upwardly from the hole that receives the pin 33 and a draw bolt I96 is provided for drawing the top parts of the bracket together to tightly clamp the pin in position. The bracket I92 is clamped to the platform 15 by a bolt I91. This bolt extends through the slot I95 and when loosened, permits horizontal or radial shifting of the bracket I92 for moving the axis of the shaft I12 either toward or away from the axis of spindle 25.

In order to insure accurate radial movement of the bracket I92, when it is being shifted horizontally, there is provided a tongue I99 on the bottom of the base I94 of the bracket which slides in a radially extending groove 289 in the platform I5. The shifting of the bracket I92 is accomplished by turning either of two bolts 282 or 203. For this purpose, there is provided 50 a block 204 secured to the platf0rm "I5 by a bolt 205. The block 284 is threaded to receive the screw 292. Head 28? of bolt 202 engages the outer edge of base I94. The end of bolt 293 abuts block 284 and is threaded in the base I94. When 55 the bolt I91 is loosened, the bracket I92 can be shifted to the right or left as viewed in Fig. 4. If it is desirable to move the bracket to the right or radially inwardly, the bolt 203 is turned so that it moves to the left i. e. away from the block go 204. Then bolt 282 is turned so that the head 2871 draws the base I94 of the bracket I92 to the right. When the desired position is attained, bolt It? is tightened to clamp the bracket I92 in position. If it is desirable to move the bracket I92 to the left or radially outwardly, bolt I91 is first loosened and then bolt 282 is moved to the right so that there is a clearance between the head and the edge of the base I94. Then bolt 283 is turned so that the threads thereof, after the right hand end engages the block 204, forces the base I94 to the left. Again the bolt I91 is tightened to clamp the bracket I92 in position.

Micrometer calibration is provided for determining the exact position of the bracket I92 for Id the purpose of resetting the axis of a spindle H2 to an exact position previously desired for, certain size vision and distant fields. For this purpose, the stationary part 203 of a micrometer 2|! is secured to the inner edge of the bracket I92 by a set screw 2. The movable part 2I2 of 'the micrometer 2I6 is threaded on to the stationary part 209 in the usual manner. The right hand end of the movable part 2I2 is arranged to engage an abutment 2I4 on a block 2 I5 secured to the platform 15. When the desired setting is eflected, the movable part is moved to the right until the end thereof engages the abutment 2 and a reading taken on the calibration of the micrometer. In the event that the machine is used alternately for different area vision fields in which the bracket I 92 is shifted, it can be readily reset to the exact position by reference to the previous recordings taken for the desired settings of the particular area of the field.

From the foregoing, it will be seen that the abrading wheels 20 can be individually shifted in all the directions necessary, namely, in three directions, for the purpose of varying the areas of the respective near vision and distant fields and for the purpose of individually varying the curvatures of the respective fields. If it is desirable to change the width of the near vision field, the bracket I92 carrying the pivot 33 for arm 3i is shifted horizontally. To change the curvature, the axis of rotation of wheel 20 is shifted by rotating sleeve I14 on arm 3|. Whenever either of these corrections or changes is made, it is usually necessary to again reset the height of the wheel 20 and this is accomplished by manipulating the nuts I9 I. For most accurate results, it is desirable that the abrading surface of the wheel be in plane intersecting the pivotal center of the pin 33 and the bottom of stop 35.

The usual working or cooling liquid is delivered to the abrading and abraded surfaces during the abrading operation and this liquid is delivered to these surfaces at each of the stations by a tube 2I8. The nozzle end 2I9 of this tube is directed inwardly so as to flush the turning surfaces. A tube extends through a bracket 22I carried by the sleeve I14 and the upper end thereof is provided with a shut-01f valve 222. Fluid is delivered to the shut-off valve 222 by a flexible hose 223 which is connected by a check valve 224 with .a manifold 225 through a pipe 226. The check valve is provided with disc type valve 221 yieldingly held in position by a spring 228. The top wall 229 of the valve is removably held in position by a removable stirrup 230 which latter is held in place by a screw 23I. A valve 234 (Fig. 1) controls the flow of fluid to the manifold 225. A hose 235 conducts the fluid to the valve 234. Cooling liquid is delivered to the abrading surfaces only during the abrading time and the flow thereof is stopped automatically at the valve 234 as soon as the table 62 is lowered, and, the valve 234 is not opened until just prior to the start to the next abrading operation. For this purpose, there is provided a push rod 233 (Figs. '1 and 8) which opens the valve 234 when the table 62 forces the push rod 236 to valve opening position. Valve 234 is of the type which automatically closes when the pressure, by the push rod 236 thereon, is released. The valves 224 are forced open by hydraulic pressure on the cooling liquid and as soon as this pressure is released, due to the closing of the valve 234, the spring 228 closes the valve 221 on its seat. The purpose of the check valves 224 is to prevent any of the tubes 223 from siphoning liquid from the manifold during the period when valve 234 is closed.

There will be some drip from the tubes 2I8 after the valve 234 is closed and for this purpose there is provided a plurality of drip pans 238 which are secured to and span the upper part of casing sections I41. Each of the drip pans is provided with an outlet 239 which is connected by downwardly extending pipes 248 which lead to the basin I48a therebelow. These basins are connected by drip pipes 242 with the drain chamber or trough 12, whence the cooling liquid is returned to a settling chamber, not shown. Liquid is pumped from the settling chamber to the pipe 235 by a pump, not shown. The usual type of cooling liquid is employed and comprises a mixture of soluble oil and water.

Referring specifically to Fig. 1 and somewhat to Fig. 2, it will be seen that the three wires for conducting electric current to the motors 2| are indicated at 244. These wires lead to a switch box 245 whence they extend to and from the switch 18 through a conduit 246 to the switch box 245. In the switch box 245, they are connected to sockets 248 and then connected by plugs 249 and conduits 250 to the motors 2|. This switch box is carried by the post I69 and rests upon the manifold 225, and is locked in position by set screws 25I. The manifold 225 rests upon the bracket I68 and this bracket is held in position on the rod I69 by a set screw 253.

Again referring to Fig. 1, the pump I26 is driven by an electric motor 255 through pulleys 256 and 251 and belt 258.

The electrical circuit for the signal light 263 which is mounted on the stationary table 15 adjacent to the reloading station A in a position in which it is convenient for observation by the operator is shown in Fig. 11. The stops 35, which limit the swingin movement of the lever 32 and thereby the extent of downward movement of arm 3i, carry stationary electrical contacts 26Ia and the ends of arm 34 carry contacts 26I. All of the contacts 26I and 26I a and the light 260 are connected in series circuit relation with a source of electrical energy herein shown as a battery 262. The circuit includes battery 262, wiring 263, light 260, wire 264, stationary contact 26Ia, contact 26I, bolt 266, connector 261, wire 268 which connects with the next stationary contact 26I a thus through all of the contacts 26I and 26Ia and all of the interconnecting wiring to wire 210 which lead to the opposite side of the battery 262. After all of the abrading operations are completed, all contacts 26I will be in contact with their respective contact stops 35 to thus complete the circuit to the signal light 2'30. The operator then shifts the lever 212 for actuating the valve I34 in the manner previously described.

Preferably, more than two sets of locating pins 13 and sockets 14 are employed for accurately locating the table 62 in position in which abrading takes place. By employing six sets, the resulting pressure between the table 62 and platform 1-5, when the table is forced into abrading position, is distributed equally circumferentially between the platform and table. This equal, circumferential distribution of pressure prevents distortion of the table and platform. Distortion of either table or platform would cause misalignment of the lens blank and abrading wheel.

Operation While the operation has been described in connection with the preceding detailed description of the device illustrating my invention, a general description of the more important features the operation will be also given here. Referring to Fig. 1, it may be seen that there are six stations designated as A, B, C, D, E, and F at four of which there are motors 2 I, and at the other there is the gauge 90. During abrading operation there is a lens carrier 24 adapted to support a lens 23 also associated with each station. Each such lens carrier 24 is (as is shown more clearly in Fig. 3) mounted upon a rotatable spindle 25, such spindles being mounted on a movable table 92 and being adapted at times to be driven by gear trains from a motor 29. During abrading operation the electric motors 2| are mounted above the lens carriers 24 and at such times drive abradin wheels 29. The motors 2! are mounted upon pivoted arms 3! on a stationary table I5. The table 62 is rotatably mounted for rotation about the central axis of the machine as is shown more clearly in Fig. 2 and also is arranged for vertical movement from the position shown in Fig. 2 (in which the table 62 is lowered) to the position shown in Fig. 3 (in which the table 92 substantially contacts with the table iii). The rotation and the raising and lowering of the table 62 are each accomplished hydraulically.

The hydraulic means for raising and lowering the table 62 is shown diagramatic'ally in Figs. '7 and 8 and comprises the pump I26; connecting hydraulic lines 90, I29, I3I and I39 and the fluid chamber 49. The fluid chamber 49 is in efiect a hydraulic cylinder having a piston 57 slidably mounted therein. As is shown in Fig. 2, the piston 51 is in reality a sleeve. This piston sleeve 51 carries movable table 92 on which the lens carriers 24 are mounted. It also carries a movable table 56 on which is mounted a motor 29.

The hydraulic means for rotating the table 62 is shown in Figs. '7, 8 and 9 and comprises the cylinder I93, the piston H12 therein, the extension 98 of the piston and the pivoted clutch lever 99 with its hook I0 3. The hook I09 is adapted at each reciprocation to engage one of the pins I99 and through the pins move the tables 56 and 92 through 60 of rotation.

It must be noted that when the tables 56 and 92 reach their uppermost positions the table 62 contacts and moves upward the two rods l9 and 235 (see Figs. '7 and 8). The push rod I9 operates the switch 78 (Figs. 1 and 12) to energize the motors 2i and thus the motors ii are continuously rotating and revolving their abrading wheel whenever the tables are in the upper position. However. due to the stop provided by the contact 29! on the outer ends of the arms 39 of the levers 3i (see Fig. 3) the abrading wheels 29 do not grind the lens beyond the limit for which the operation is set. The valve rod 236 operates a valve 234 (see Fig. 1) which controls the flow of cooling fluid so that whenever the table I52 is in its uppermost position, cooling fluid under pressure is supplied to each of the abrading stations to keep the lens being ground and abrading wheel acting thereon cool during the abrading operation. The motor 29 is also energized and driven whenever and only when the table reaches its uppermost position. The contact 69 (see Fig. 2) is raised with the table 59 and contacts with one of the contacts in and through the circuit thus formed. electricity is thus supplied to the 14 lens on the particular lens carrier 24 which is then at station A, removing the movable section I50 of the oil protecting cover 6- (see Fig. 3) in order to do so. He then operates valve I34 manually by means of the handle 212 (see Fig. 1) to move the valve from the position shown in Fig. '7 to that of the position shown in Fig. 8. Liquid driven by the pump I26 flows through the conduit I29, the valve I40, the conduit I39, the valve I23,

and the conduit 60 to the fluid chamber 49. Fluid also flows through the conduit I38 to the cylinder I03 moving the piston I92 to the position shown in Fig. '8 but this has no effect on the table inasmuch as the cam surface In of the clutch lever 99 (see Fig. 9) causes that clutch lever to pivot against the action of the spring I96 and slide over the next pin I99 (preparatory to the next action of rotating the table 62). This does not disturb the position of the table 62 which is held releasably in position by the rollers II 5 of the lever H4. Inasmuch as the lens 23 is not in a position to have any operation performed upon it, the operator immediately again operates the valve I40 moving it from the position shown in Fig. 8 to that of the position shown in Fig. '7. As may be seen, this connects the chamber 49 through conduits 99, I39 and I3I with the reservoir I27 and the weight of the tables 59 and 62 causes the tables together with the piston 51 to be lowered to the position shown in Fig. '7. When the tables reach the position shown in Fig. '7, the table 59 contacts with-the rod of the valve I91, opening that valve and inasmuch as the pump I28 is supplying fluid under pressure through the conduit I29, the valve I34, the conduit I36 to the valve ml, the fluid under pressure may now pass through the conduit I3? to the cylinder I93 and force the piston I92 to the right (as shown in Fig. 7 and in Fig. 9). The piston I02 through the extension 98:, the clutch lever 99 and the hook I94 rotate the tables 58 and 62, 60 in a clockwise direction as shown in Fig. 9. The valve is again moved to raise the tables as before. Another lens carrier will now be in the position of station A and another lens blank may be placed upon such lens carrier. The operation may be repeated but at this time the motor 2I at station B will operate the abrading wheel there to perform a grinding operation on the first lens. This grinding operation being completed, the arm 34 of the levers M will cause an electric circuit to be completed through all the contacts 26I (see Fig. 3) to operate the signal 260 and will give a signal to the operator that the operation is completed. The operator again operates the valve I34 manually to lower the tables and to rotate it. Then he operates the valve I34 again to raise the tables and places a new lens on the next lens carrier 24 at station A. This operation is continued until the original lens arrives back at station A. Thereupon the operator removes the lens which is now finished from the lens carrier at station A and inserts a new one in its place and So continues.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow:

I claim:

1. In a lens grinding machine in combination, mechanism forming a plurality of work supports for lens blanks; mechanism forming a plurality of grinding tools adapted to be associated with lens blanks carried by the lens blanks supof fluid pressure, pressure responsive means for successively moving one of said mechanisms to change the relative position of the work supports and tools, pressure responsive means for moving one of said mechanisms toward the other,

a valve selectively movable for connecting the source of pressure either with the first or second mentioned means, a valve for controlling the flow of fluid to one of said pressure responsive means;

and means responsive to operation of the other pressure responsive means for preventing opening of the second valve until the said mechanism actuated thereby has moved to a predetermined position.

2. In a lens grinding machine in combination, mechanism comprising a table rotatable about a vertical axis and havin a plurality of rotatable lens blank supports; a, plurality of rotatable grinding tools adapted to be associated with lens blanks carried by the lens blanks supports; a fluid pressure circuit including a source of fluid pressure, pressure responsive means for successively rotating said table mechanisms to change the relative position of the lens blank supports and tools, pressure responsive means for moving said table mechanism toward the rotatable grinding wheels, a valve selectively movable for connecting the source of pressure either with the first or second mentioned means, a valve for controlling the flow of fluid to the second mentioned pressure responsive means and means responsive to the vertical movement of the table for preventing opening of the second valve until the table has been moved to a predetermined position by the first mentioned pressure responsive means.

3. In a lens grinding machine in combination, mechanism comprising a table having a plurality of rotatable lens blank supports; grinding mechanism comprising a plurality of abrading wheels adapted to be associated with lens blanks carried by the lens blank supports; a fluid pressure circuit including a source of fluid pressure, pressure responsive means for successively rotating said table to change the relative position of the lens blank supports and abrading wheels, pressure responsive means for moving said table vertically toward the abrading wheels; means responsive to vertical movement of the table for rotating the abrading wheels; means responsive to vertical movement of the table for rotating the lens blank supports; a valve selectively movable for connecting the source of pressure either with the first or second mentioned means, a valve forcontrolling the flow of fluid to the first mentioned pressure responsive means; and means responsive to the vertical movement of the table for preventing opening of the second valve until the second mentioned mechanism has been moved to a predetermined position by the second mentioned pressure responsive means.

4. In a lens grinding machine in combination, mechanism comprising a table having a plurality of rotatable lens blank supports; abrading mechanism comprising a plurality of abrading wheels adapted to be associated with lens blanks carried by the lens blank supports; a fluid pressure circuit including a source of fluid pressure, pressure responsive means for successively moving said table rotatably to change the relative position of the lens blank supports and abrading wheels, pressure responsive means for moving said rotatable table toward the abrading wheels, a valve selectively movable for connecting the source of pressure either with the first or second mentioned means, a valve for controlling the flow of fluid to the second mentioned pressure responsive means, a valve for controlling the flow of fluid to the first mentioned pressure responsive means; m'eansresponsive to the vertical movement of the table for preventing opening of the second valve until the first mentioned mechanism has been moved to a predetermined position by the first mentioned pressure responsive means; and means responsive to the rotation of the table for preventing opening of the second mentioned valve until the table has been moved to a predetermined position by the second mentioned pressure responsive means.

5. In a lens grindin machine in combination, a rotatable and vertically reciprocable table; a plurality of work performing stations associated with said table; a lens grinding mechanism associated with each of a plurality of said work performing stations; 2. fluid pressure circuit including a source of fluid pressure, pressure responsive means for rotatably moving the table from station to station, pressure responsive means for moving the table vertically to positions adjacent to said lens grinding mechanism, a valve selectively movable for connecting the source of pressure either with the first or second mentioned means, a valve for controlling the flow of fluid to the second mentioned means; and means responsive to the rotation of the table for preventing opening of the second mentioned valve until the first mentioned means has rotated the table to a work performing station.

6. In a lens grinding machine in combination, a rotatable and vertically reciprocable table equipped with a plurality of lens holding devices; a plurality of work performing stations associated with said table and each equipped with a rotatable lens grinding abrading wheel; a fluid pressure circuit including a source of fluid pressure, pressure responsive means for rotating the table from a position in which one of said lens holding devices is positioned adjacent to one of said work performing stations to a position in which said lens holding device is positioned adjacent to another of said work performing stations, pressure responsive means for reciprocating the table toward said abrading devices, a valve selectively movable for connecting the source of pressure either with the first or second mentioned means, a valve for controlling the flow of fluid to the flrst mentioned means; and means responsive to the operation of the second mentioned means for preventing opening of the second mentioned valve until the second mentioned means has reciprocated the table to a predetermined position.

7. In a lens grinding machine in combination, a table having a plurality of lens supporting devices; a plurality of work performing stations associated with said table and each having a lens grinding mechanism; a fluid pressure circuit including a source of fluid pressure; pressure responsive means for rotating the table from a position in which one of said lens supporting devices is associated with one of said work performing stations to a position in which said lens supporting is associated with another of said work performing stations; pressure responsive means for reciprocating the table toward said work performing stations; a valve selectively movable for connecting the source of pressure either with the first or second mentioned means; a second valve for controlling the flow of fluid to the secamazon 0nd mentioned means; a third valve for controlling the flow of fluid to the first mentioned means; means responsive to the operation of the first mentioned means for preventing opening of the second valve until the first mentioned means has rotated the table to a position in which a lens supporting device is at a work performing staand means responsive to the operation of the second mentioned means for preventing opening of the third valve until the second mentioned means has reciprocated the table to a predetermined position.

8. In a lens grinding machine in combination, a table having a plurality of work supporting devices; a plurality of work performing stations associated with said table and each having a lens grinding mechanism; a fluid pressure circuit including a source of fluid pressure, pressure responsive means for moving the table from station to station, pressure responsive means for moving the table laterally of the first mentioned movement, a valve selectively movable for connecting the source of pressure either with the first or second mentioned means, a valve for controlling the flow of fluid to one of said pressure responsive means; and means responsive to the operation of the other of said pressure responsive means for preventing opening of the second valve until the table has been moved to a predetermined position by said other pressure responsive means.

9. In combination, a stationary tablej a rotatable table, one of said tables being movable toward and away from the other table; a plurality of working tools carried by one of said tables; a plurality of lens holding devices carried by the other said table; one of said tables having at least three sets of locating pins carried thereby and'spaced thereabout and said other table having sockets for receiving all of said locating means when the tables are moved another; and means relative to one another.

The following re toward one for moving said elements PERRY OKEY.

REFERENCES CITED file of this patent:

UNITED STATES PATENTS Number ierences are of record in the Name Date Scheuerle July 27, Coleman Oct. 24, Bentzon Jan. 13, Challet Apr. 9, Quimby Aug. 6, Hunt Nov. 5, Fisher Mar. 30, Taylor Dec. 27, Taylor 'Oct. 17, Bugbee Dec. 19, Schuessler Mar. 13, Wilson Apr. 2, Hanson Dec. 10, Doane Nov. 17, Desenberg Apr. 25, Summey May 16, Blood et al. Aug. 29, Lovejoy Dec. 5, Lovejoy Feb. 13, Carlson Aug. 7, Vanderbeek Mar. 1, Parker Dec. 19, Wallace Mar. 26, Stacy June 1, Desenberg June 20, Hoppe Oct. 24, Jearum May 1, Jearum Sept. 4,

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