US2286361A - Abrading machine - Google Patents

Description

June 16, 1942. L. w. GODDU ABRADING MACHNE Filed March 27, 1959 8 Sheets-Sheet l S I INVENTOR. [Am 0 W 60000 RNEY.

. June 16, 1942.

L. W. GODDU ABRADING MACHINE Filed March 2'7, 1939 .8 Sheets-Sheet 2 INVEN TOR. 440m W 6'00Du Fig 11 June 16, 1942. L. w. GODDU ABRADINGMACHINE Filed March 2'7, 1959 8 Sheets-Shet s iii-9:3

47 I [40m N @0500 4% TTORNEY.

June 16, 1942. L. w. GODDU ABRADING MACHINE Filed March 27, 1939 8 Sheets-Sheet 4 I 3 6%; mmmm 13 A40 Y0 2 0000- BY 3 June 16, 1 942. L. 'W. GODDU 2,286,361

ABRADING MACHINE Filed March 27, 1959 v s Sheets-Sheet e zlil iliiiiilh'iiiil lllllfg FiSJEII INVENTOR. 14020 N aaou if TTORNEY.

June 16,1942.

L. W. GODDU ABRADING MACHINE Filed Mafch 27; 1959 8 Sheets-Sheet 7 Z Ja June 16, 1942.

1.. w. eooou ABRADING MACHINE Filed March 27, 1939 8 Sheets-Sheet 8 INVENTOR.

BY [60)0 W 6000; 4 w- 8 W AT RNEY.

Patented June 16, 1942 2,286,361 V ABRADING MACHINE Lloyd K. Goddu, Southbridge, Masa, assignorto American Optical Company,

Southbridge,

Mass., a voluntary association of Massachusetts Application March 27, 1939, Serial No. 264,329

9 Claims. 51-131) This invention relates to improvements in abrading devices and has particular reference to improved means and method of abrading lenses.

One of the principal objects of the invention is to provide an abrading machine whereby several different curve generations may be obtained with a single generating tool in a minimum amount of time, in a simple and efficient manner and with extreme accuracy.

Another object of the invention is to provide a cupped type abrading tool and associated mechanism whereby the abrading tool may be tilted to different controlled angles for generating surfaces of different curvature and has particular reference to novel means for obtaining the initial adjusted position of the tool and the work whereby the amount removed during the abrading is definitely controlled.

Another object is to provide an abrading machine of the above character whereby a cooling and lubricating liquid may be set onto the tool and work during'the abrading operation and be confined to said working parts of the tool.

Another object is to provide means for automatically stopping the machine at the completion of the abrading operation.

Another object is to provide a machine of the above character whereby the source of power for operating the machine is confined within the machine as an integral unit.

Another object is to provide a machine of the above character which is relatively simple and durable in construction and the parts thereof which are adjustable relativeto each other are positively and rigidly supported during the abrading operation and with which extreme accuracy of curve generation is obtained.

Another object is to provide a machine of the above character having a tilting head for supportinlgl the tool generally carried by a relatively large -surface bearing for the elimination of looseness and play during the abrading operation 7 and to reduce wear over a relatively long period of use. Another object is to provide an abrading tool 'liaving a curved abrading surface for disposing a cliiferent effective portion of the tool to the work when set for different curve generations and associated mechanism for supporting said tool whereby the said tool will be tilted substantially' about the center of the curved abrading surface of the tool.

Another object is to provide an abrading tool of the above character and associated mechanism for supporting said tool whereby the'center of curvature of the tool may be adjusted relative to the center about whichthe tool is tilted to compensate for wear of the effective abrading surface of the tool.

v Another object is to provide an abrading tool, for machines of the above character, which is constructed according to the average percentage of surfaces, plus and minus, to be formed by said tool so that the tool will perform its maximum efficiency as regards the generation of both types of curvature prior to fulfilling the extent of its usefulness for the generation of any one of said curvatures.

Another object is to provide associated mechanism for tools of the above character whereby the said tool may be supported substantially about the center of curvature of the effective abrading surface of the tool.

Another object is to provide an arrangement in devices of the above character wherebs the tools may be quickly and easily interchanged when worn and which may be simply and easily adjusted to abrading position.

Another object is to provide a novel method of accomplishing all of the features set forth above.

Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawings and it will be apparent that many changes may be made in the details of construction, arrangement of, parts and methods shown and described without departing from the spirit of the invention as expressed in the accompanying claims. I, therefore, do not wish to be limited to the exact details of construction,

arrangement of parts and methods shown and described as the preferred form only has been given by way of ill ration.

Referring to th drawings:

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

Fig. 11- is a left side elevation of the device illustrated in Fig. I;

Fig. III is a right side elevation of the device illustrated in Fig. I;

Fig. IV is an enlarged fragmentary sectional view taken as on line IVIV of Fig. I;

Fig. V is a slightly enlarged fragmentary sectional view taken as on line V'-V of Fig. I;

FigpVI is a slightly enlarged fragmentary sectional view taken as on line VI-VI of Fig. III

showing the relatively large surface bearing supporting the tilting head of the device and the associated driving mechanism.

- tra cost of production.

Fig. VII is a fragmentary sectional view taken as on line VII-VII of Fig. II showing the lower drive connection and means for taking up looseness and play in the driving belt;

Fig. VIII is an enlarged sectional view taken as on line VIII-VIII of Fig. III showing the associated mechanism for tilting the head of the device;

Fig. IX is an enlarged fragmentary sectional view taken as on line IX--IX of Fig. III and looking in the direction indicated by the arrows;

Fig. X is an enlarged fragmentary sectional view taken as on line X--X- of Fig. I and looking in the direction indicated by the arrows;

Fig. X! is an enlarged face view of a modifled form of abrading tool;

Fig. XII is a fragmentary sectional view of the tool illustrated in Fig. XI;

Fig. XIII is a sectional view taken as on line XIII-XIII of Fig. III; and

Fig. XIV is a schematic diagram of the oil supply and pump in connection with the electric circuit therefor.

Prior to the present invention, it has been usual to reduce lens blanks to substantially the finished thickness desired just prior to the forming of the finished optical surface thereon by hand abrading operations requiring the use of a plurality of roughing laps of different surface curvatures andloose abrasives. Such abrading operations not only were undesirable from the standpoint of cost, inherent to the requirement of a plurality of different laps, but also depended greatly upon the accuracy and skill of the operator. Such abrading operations were also inefiicient due to the great amount of time required in reducing the blanks to the thickness required and also, due to its depending upon the skill of the operator, introduced inaccuracies which oftentimes resulted in the loss of the blank and therefore introduced wastage and ex- One of the prime factors, therefore, of the present invention is to eliminate all of the above procedure through the provision of a single abrading tool and associated mechanism whereby surfaces of different curvatures may be quickly and easily formed by said tool without the necessity of the use of loose abrasives and without depending upon the skill and accuracy of the operator.

Referring more particularly to the drawings wherein like characters of reference designate like parts throughout the several views the device embodying the invention comprises a housing I having a head 2 pivotally attached thereto by a relatively large surface bearing 3, see Figs. VI and VIII.

The housing I has a work, supporting spindle 4 rotatably mounted thereiny 'lhe spindle 4 is rotatably supported in a sleeve 5 longitudinally movable in a bearing 5 supported by a web I internally of the housing I. The spindle 4 is supported adjacent its opposed ends by ball bearings 8 and 9 mounted internally of the shouldered recesses I and II in the sleeve 5. The spindle 4 is held against longitudinal movement in the sleeve by a plate l2 attached to the upper end of said sleeve by screws or like means l3. The plate l2 overlies the bearing 8 which,

in turn, engages an upper shouldered edge l4 on the spindle 4 adjacent the upper end of said spindle 4. The lower end of the spindle 4 is provided with'a reduced threaded portion I5 on v which a pair of lock nuts 13 are threadedly attached. The said nuts l5 are adapted to retain the bearing 3 in desired relation with the spindle 4. The spindle 4 is provided with a reduced extension I! fitted within a sleeve-like bearing.

member IBsupported internally of spaced ball bearings I9 and". The reduced extension I! is keyed to the sleeve-like bearing 18 so as to rotate as an integral unit, and to permit longitudinal movement of said reduced extension I! internally of said sleeve-like bearing 18. The sleeve-like bearing I8 is held in desired relation with the spaced ball bearings l9 and 20 by a pair of lock nuts 2| adjacent the upper end thereof and a plate 22 adjacent the lower end thereof. The plate 22 is secured to the bearing 6 by means of a plurality of screws or the like 23. The sleeve-like bearing 18 has adrive pulley 24 attached thereto by a slot-and key connection 25. The pulley 24 is secured to the sleeve-like bearing l8 by means of a set screw or the like 26. The upper end of the spindle 4 is provided with a threaded portion 21 on which a shield 28 is fitted and held thereon by means of a nut 29. Directly above the threaded portion 21 the spindle 4 is provided with a tapered end 30. The tapered end 30 has an interchangeable hardened tapered nose 3| secured thereto bya screw or the like 32. The tapered nose 3| is preferably hardened to resist wear and is adapted to support the block adapter 33, see Fig. I. The block adapter 33 is provided with a shank 34 having a tapered recess 35 therein which is fitted on and frictionaliy binds with the tapered nose 3|.

Referring back to Fig. V, the sleeve 5 is provided with a rack 36 secured thereto by screws or the ,like 31. The rack is fitted within a suitable slotted recess in the side of the sleeve 5. The rack 36 has a dual function. One of its functions is a key-like member interengaging with the side walls of alongitudinal slot 38 formed in the bearing 6 for holding the said sleeve 5 against rotation and its other function is to cooperate with a pinion 39 by which the sleeve 5 may be moved longitudinally of the bearing 6. The upper end of the sleeve 5 is provided with a flange-like shoulder 40 which is adapted to engage the upper end 4| of the bearing 5 for limiting its downward movement. The upper end of the sleeve 5 is provided with a seat 42 to which a splash guard or pan 43 is attached. The splash guard or pan 43 has a depending lip 44 to which a suitable apron 45 is attached, as by screws or the like 46. The splash guard 43 and depending apron 45 together with the shield 28 are adapted to prevent the abrasive from flowing in the hearing. The spindle 4 is rotated by means of the pulley which is connected through a belt 41, through a similar pulley 48, driven by a motor 49 supported in the housing I, see Figs. III and VII. The belt 41 is held taut by means of a spring pressed roller 50 carried by a link 5| pivotally attached at 52 to the inner wall of the housing and held under tension by a spring The lens blank 54 to be abraded is secured to the block 55 as by pitch or other suitable adhesive. The block 55, in turn, is mounted and held in the adapter 33. as by screws or the like 56. The adapter 33 is provided with a shouldered recess 51 in which a reduced shank on the block 55 is fitted. The shank is held in the shouldered recess by screws or the like 56, see Fig; I.

The abrading tool 58, as shown in Figs. I and IV, is of an annular shape having a curved abrading portion'53 preferably formed of metal or of a plurality of abrasive particles, such as crushed diamonds, sapphires, or any other desired abrasive particles. The annular body portion 58 of the tool is secured to a hub 88 having a. reduced extension 8| extending within the central opening of the annular body portion 58. The portion 58, as shown in Fig. IV, is secured to the hub 88,

as by screws or the like 82. It is to be understood, however, that the contiguous surfaces 63 may be joined with each other as by solder or the like. The hub 68 is provided with a tapered opening 64 which fits on and binds with the tapered end 55 of a driving spindle 58. The spindle 68 is mounted in spaced ball bearings 81 and 681 The said ball bearings are supported in shouldered recesses 69 and-18 internally of a sleeve or quill H. The spindle 86 has a pulley 12 keyed thereto, as illustrated at 13, and is held thereon by means of a nut 14 threadedly connected with the threaded end 15 of the spindle 55. The nut 14 is adapted to take up any looseness or end thrust play in the spindle 68 and is adjustable to compensate for wear. A suitable screw 18, cooperating with serrations 11 formed in the periphery of the nut 14, is provided to lock the said not in adjusted position. The quill or sleeve 1| is adjustably supported in the hollow bore of the front portion 18 of the head 2. The portion 18 of the head 2 is integrally joined with a hollow casing 19 which, in itself, is integrally joined with a bearing member 88, see Fig. VI. The bearing member 88, as shown in Figs. II, III and IV, is fitted between the spaced bearings 8| and 82 on the upper portion of the housing I. Said bearing 88 and spaced bearings 8| and 82 are provided with aligned relatively large openings in which is fitted a hollow bearing pin 83, see Figs. III and VI. The hollow bearing pin 83 is preferably pressed into binding relation with the walls of the openings of the spaced bearings 8| and 82 for retaining it in position. The bearing 88 is preferably split, as illustrated at 84, so as to provide portions which, through a suitable binding screw 85, may be drawn into clamping relation with the hollow bearing pin 83. To insure the hollow bearing pin 83 against movement in the spaced bearings 8| and 82, suitable means, such as a key or the like 86, is provided. It is to be understood that both of the bearings 8| and 82 may be provided with similar keys if desired. The lock screw 85 is adapted to lock the head 2 in desired angular position. When it is desired to move the head 2 to a different angular position, the screw 85 is slightly loosened and the head 2 is tilted to a desired position determined by a suitable degree scale 88 and vernier 89, see Fig. I, and the said screw 85 is then tightened.

It is to be noted, by reference to Fig. I, that the head 2 pivots about an effective'center 98, which center is preferably located in axial alignment with the center of curvature 9| of the curved abrading surface 59 of the tool 58. The

center 9I is initially positioned in axial alignment with the effective center of rotation 98 of the.- head 2 by adjusting thequill or sleeve 1| longitudinally of the hollow bore in the front portion 18 of the head 2. The quill or sleeve 1|, as illustrated in Figs. III and XIII, is held in adjusted position in the front portion 18 of the head 2 by means of spaced wedge blocks 92 and 93 which are drawn into binding relation with each other by means of a suitable screw or the like 94. The wedge blocks 92 and 93 move in a direction transversely of the longitudinal axis of the sleeve 1| and are each provided with curved the side surface of the sleeve II.

bearing surfaces 95 and 98 which are adapted to be moved into and out of binding relation with When it is desired to adjust the sleeve 1| longitudinally of the front portion 18 of the head 2, the screw 94 is loosened and the sleeve 1| is moved an amount suificientto substantially position the center 9I of the curved face 59 of the tool in axial alignment with the effective center of rotation 98 of the head 2. The wedge blocks 92 and 93 are normallyurged in. a direction away from each other by means of a suitable spring or the like 91.

It is to be noted that by supporting the center 9|, of the curved face 59 of the abrading tool substantially in axial alignment with the center of rotation 98 of the head 2, the tool will remain in constant relation with the work or lens blank 54 to be abraded, that is, there will be no change of the tool relative to the lens in a sidewise direction brought about by angling the head. This arrangement also causes a different portion of the effective abrading surface 59 of the tool to move into abrading relation with the blank when the said head 2 is adjusied to different angular positions and thereby causes the said abrading surface to be more durable and eflicient as the entire effective abrading surface of the tool is utilized during the abrading of different curved surfaces.

It is to be understood that the present abrading machine is designed particularly for forming rough ground surfaces so that the absolute align- Y driven through a flexible shaft I88 by the motor 49. It is to be understood that the speed of rotation of the spindle 68 is greater than the speed of rotationof the spindle 4. This is effected through a direct driving connection with a motor 49 and through the use of a reduction gearing |8I between the rotor of the motor 49 and the associating driving mechanism of the spindle 4. The reduction gearing I 8| is of the usual conventional type and is not shown in detail, it is merely located at I8I within the housing of the motor.

Theflexible shaft I88 has coupling ends I82 and I83. The end I83 is preferably integrally connected with a coupling member I81 rigidly secured to the stem I88 of the motor 49, as by a set screw or the like I89 and its opposite end I82 is slidably keyed within a bearing H8. The

bearing 8 is rotatably supported within spaced bearings I84 and I85. The end I82 is adapted to have a sliding movement in the bearing H8 and is locked against rotation therein by means of a suitable key or the like I.

The spaced bearings I84 and I are carried by a slide block II2 mounted in a slideway H3 in the upper portion of the hollow casing 19. The-slide block H2 is adjusted toward and away from the sleeve 1| by means of a screw or the like II 4, see Fig. III. The purpose of this slide block is to provide means for adjusting the pulley 98 in a direction away from the pulley 12 to keep the belt 99 taut.

The flexible shaft I88 is provided with a flexat II6, internally of a housing II1 fitting about the outer portion of a bearing I06 carried by the re' uced extension II8 of the coupling member I The reduced extension H8 is provided with a recess in which the end of the flexible in a bearing I 22attached to the slide block 2,

as by screws or the like I23. The sleeve I2I is provided with. a slot I24. A suitable key member I25, mounted on the bearing I22, has an end extending into the slot I24 to hold the said sleeve against rotation and yet permit it to move 1ongitudinally within the bearing I22. The longitudinal movement of the sleeve I2I and the end I02, relative to the respective bearings I22 and H0, is to allow free swinging movement of the head 2 and to compensate for any slight variations in the length of the shaft I00 at different tilted positions. The flexible shaft I00 and casing H5, in this particular instance, extend through suitable diametrically opposed openings I26, I21, I28 and I29, in the bearing 80 and hollow bearing pin 83. The angling of the head 2 is effected by means of a section of worm gear I30 secured to the bearing member 80 by means of screws or the like I3I, as illustrated at Fig. VIII. The worm sector I30 meshes with a worm I32 carried by the shaft I33 rotated by a hand wheel or the like I34. Prior to manipulating the hand wheel I 34 the clamp screw 85 is loos-.

ened to release the gripping section of the lips 81 with the hollow bearing pin 83. The adjustment is made through the cooperating degree scale 88 and vemier 89 which determines the angular set and the screw 85 is then tightened to.

hold the adjustment.

To determine the initial position of the tool relative to the work and to control the amount of glass which is to be removed during the abrading operation there is provided a mechanism such as illustrated in Figs. IX and X. This mechanism comprises a gauge arm I35 pivotally connected at one of its ends, as illustrated at I36, to a shaft I31 and having at its opposite end a gauge pin I38. The shaft I31 has a side cam member I39 on its end opposite the pivotal connection I36. The side cam I39 is provided with a cam surface I40 which is adapted to engage the end I4I of a spring pressed pin I42. The spring pressed pin I42 is slidably supported in a bearing I43 in the side of the housing I. The inner end of the pin I42 has a gauge pin I44 thereon of the same exact length as the gauge pin I38. A suitable spring I45 is provided for constantly urging the pin I42 toward the cam surface I40 and also to compress the operating plunger I46 of a safety switch I41. The innerend of the pin I42 is provided with a lip I48 which is adapted to engage the plunger I48 of the switch I41 when the pin I42 is moved toward the cam surface I40 by the resilient means I45.

. to assume a position in axial alignment with a contact I50 on the micrometer screw I5I. The

ing I52 carried by the upper part of a protruding portion I53 of the housing I. The micrometer screw I5I has a scale I54 cooperating with a suitable scale indicator I55. Directly in alignment with the micrometer screw I5I is a plunger I 56 slidably supported in a bearing I89. The plunger I56 is provided at its upper end with a contact face I58 adapted to engage with the lower end of the gauge pin I44. The upper end of the gauge pin I44 is adapted to engage with the end I50 of the micrometer screw III. The plunger I56 at its lower end engages with a lever I59 pivoted at I60. The lever I59 engages with a plunger I6I of a suitable switch I62 adiacent one end thereof and engages. as illustrated at I63, with a spring pressed plunger I84 carried by a suitable member I65 secured to the housing I by means of screws or the like I88. The screws I66 extend through a longitudinal slot I61 formedin the adjustable member I so that when the said screws are loosened the adjustable member I65 may be moved upwardly or v operates the plunger I64. The pin I56 is mounted in a bearing I69 slidably mounted in an outer bearing I10. The outer bearing I10 is secured to the side of the splash pan 43 by means of screws or the like I1I. The bearing I10 is split, as illustrated at 112, and is provided with a lock screw I13 operated by a lever I14. The bearing I69, therefore, is free to move longitudinally of the outer bearing I10 when the clamping action of the screw I13 is released and is adapted to be locked against longitudinal adjustment when the clamping screw I13 is tightened. A coil spring I15 normally urges the bearing I69 in an upward direction. The lower end of the bearing I69 has a saddle-like member I16 thereon which straddles the switch I62. The switch I62 is connected with the circuit, composed of lead wires I49, which is connected with the drive motor 49. The switches I41 and I62 are connected in series. The switch I41 functions merely as a cut of! switch when the initial thickness setting is beingdetermined. The switch I62 is normally closed so as to keep the circuit with the motor 49 and provides means for cutting oh the power to the motor when the abrading operation is completed.

Referring to Figs. I and V the pinion 39 which meshes with the rack 36 is operated by means of a hand lever I11. When the hand lever I11 is moved in an upward direction the spindle 4 is raised and thereby moves'the lens blank 54 toward the abrading tool 58 and vice versa.

The front of the housing I is provided with spaced guideways I18 and I19 in which is slidably mounted a baffle plate I80. The baffle plate is adapted to be moved upwardly to close the front of the device. The purpose of this baille plate is to confine the fluid used during the abrading within the housing I.

Referring again to Figs. IX and X the method of determining the amount of material to be removed from the blank 54 during the abrading operation is substantially as follows:

Assuming that the tool 58 has been adjusted so that the center of its curved face 9| is moved into alignment with the axis about which the head 2 swings and that the lens blank to be abraded and holder are positioned on the spindle 4 ready for the abrading operation and that the amount which is to be removed from the blank has been determined, the micrometer micrometer screw I5I is threaded into the bush- 75 screw I5| is adjusted to position the zero gradu- 'I35 simultaneously imparts ation of the micrometer scale I54 in alignment with the gauge edge I8I of the scale indicator I55 and the upper surface I82 is positioned in alignment with the zero indication on the scale indicator I55. The gauge arm I35 is swung upward and downward so that the gauge pin I33 is in substantial alignment with the axis ofthe This movement of the gauge arm movement to the cam I38 whereby the cam surface I40 which engages the end I of the pin I42, will move the gauge pin I44 on said member I42 into substantial alignment with the longitudinal axis of the micrometer screw II and plunger I56. Movement of the spring pressed pin I42 inwardly, as descriped above, simultaneously causes the lip I48 to move away from the plunger I46 of the switch I41 opening the circuit I49. This opening of the circuit insures that the motor will not operate during the initial setting of the device.

The hand lever I11 is then operated to move spindle 4.

the spindle 4 carrying the lens holder and blankupwardly so that the upper surface of the blank will engage the lower end of the pin I39 with the upper end of said pin simultaneously engaging the effective abrading portion of the tool 58. It is to 'be understood that the tool 58 has been previously angled to generate the curvature desired. This angling being accomplished by loosening the screw 85 and thereafter tilting the head 2 to the desired amount which is determined by the protractor 88 and vernier scale 89. The screw 85 is then tightened to retain the tool in this angular position.

This movement of the spindle 4 in an upward direction simultaneously moves the splash pan 43 upwardly and by reason of the' fact that the bearing I is connected with said splash pan the plunger I58 and associated mechanism is also moved upwardly. It is assumed that the hand lever I14 has been moved so as to loosen the screw I13 which will permit the outer hearing I10 to move freely upwardly of the bearing I69. This upward movement of the outer bearing I10 tends to impart a compressing action to the spring I15 which, in turn, raises the bearing I69 and plunger I 56. This upward movement under the resilient action of the spring I15 causes the face I58 to engage the lower end of the gauge pin I44 with theupper end of said pin engaging the end I50 of the micrometer screw I5I. The contact pin I44 has a floating connection with the spring pressed pin I42 so that engagement of both of the contact faces I58 and I50 is insured. The gauge pin I44, being of the same length as the gauge pin I38, spaces the end I50 and contact face I58 an amount substantially equal to the space between the engaged surface of the blank 54 and the abrading tool 58 as determined by the gauge pin I38. The screw I13 is then moved so as to secure the outer bearing I10 in binding relation with the bearing I69 and thereby locks these parts in rigid relation with each other. The hand lever I11 is then operated to lower the spindle 4 and move the blank 54 from engagement with the gauge pin I38. The gauge arm I35 is then' swung outwardly and downwardly to a position, such as illustrated in. Fig. X, whereby the rise of the cam surface I40 is moved out of engagement with the end I4I of the spring pressed pin I42 causing said pin I42 to be moved outwardly and simultaneously move the gauge axis of the micrometer screw I5I. ward movement of the spring pressed pin I42 simultaneously moves the lip I48 into engagement with the plunger I46 of the switch I41 and closes the said circuit I49 through the switch I41. The micrometer screw I5I is then backed off an amount substantially equal to the amount of glass to be removed from the blank. This is determined by the scale I54 and scale indicator I55. The baflle plate I80 is then raised to close the front of the device and the hand lever I11 is operated to move the blank 54 upwardly into engagement with the abrading tool 58. This upward movement of the hand lever I11 simultaneously moves the splash pan 43 upwardly and the bearing connected with said pan in said direction. This upward movement of the outer bearing I10 simultaneously moves the contact face I58 of the plunger I56 in an upward direction. It is to be noted that when the plunger I56 is moved upwardly the associated bearing I69, saddle-like member I16 and switch I62, carried by said saddle, are also moved pin I44 out of aligment with the longitudinal upwardly as a single unit. .This upward movement of the saddle I16, by reason of the fact that the arm I59 is pivotally attached to said saddle at I60, also moves the said. arm in an upward direction. This relieves the pressure ofthe spring pressed plunger I64 on the contact face I63 ,of said rock arm I59 and allows the spring pressed plunger I6I of the switch I62 to rock the arm I59 about its pivot I60 in an upward direction and simultaneously move the plunger I56 upwardly internally of the bearin I69. This automatically closes the switch I62 and the circuit I49 starting the motor which, in turn, rotates the abrading tool 58 and lens blank 54.

Suitable oil supply means may be used, such as an oil well I82a and'a pump 49a. This means may be connected with a pipe line. I82 which,

as shown by the-dotted lines in Fig. 111, ex-

tends upwardly internally of the housing I and is connected through a coupling I83 to another pipe line I84 extending to and connected with an opening I85 internally of the tool supporting spindle 66. When the switch I62 is .closed to energize the motor circuit I49, a similar circuit I49a connected with the electrically operated pump 49a is simultaneously closed causing the pump to operate and direct the lubricant upwardly of the pipe line I82 and through the central opening I85 in the spindle 66. The fluid flows outwardly of the spindle 66 internally of the annular tool 58 and is thereby directed onto the face of the blank 54 which is being abraded. The tool 58 and its associated hub is provided with a vent opening I86 to relieve excess pressure internally of the tool during the abrading operationand'thereby eliminating undue backthe blank and simultaneously allows the contact face I58 tov move into engagement with the end I50 of the micrometer screw compressing the plunger I56 which, in turn, moves'the rock arm I 59 into engagement with the spring pressed plunger I6I of the switch I62 so that when the abrading is completed this pressure would auto- This outmatically open the switch I62 and likewise open the circuit to the drive motor 49 and lubricant pump mentioned above. This function automatically stops the motor 49 and the lubricant pump and simultaneously stops rotation of the tool 58 and blank 54.

When the operation of the motor 49 is stopped the lever H4 is rotated to release the pressure of the outer bearing I72 on the inner bearing 69. The hand lever IT! is then operated to move the spindle 4 and the blank 54 downwardly away from the abrading surface of the tool 58. The baflle plate I80 is then lowered and the blank 54 removed from the spindle 4.

To generate surfaces of different curvatures the head 2 is angled, as specified above, and the various adjustments are repeated.

It is to be noted that the spring pressed pin I42 is located against rotation by means of a slot and pin connection I81 and I88. This is to maintain the gauge pin I44 in a vertical position.

It is also to be noted that the shaft I89 carrying the pinion 39 and hand lever I", as illustrated in Figs. I and II, is provided with a cam sheave I90 to which is attached a weight I9I through a flexible cord or the like I92. When the hand lever I'll is operated to move the spindle 4 in an upward direction, to engage the blank 54 with the tool 58, the cam sheave I90 is rotated to a position illustrated by the dot and dash lines in Fig. II. This moves the weight in a downward direction so that the pull of the weight on the cord I92 exerts a lever action on the cam member I90. This lever action on the cam I90 constantly tends to urge the pinion in a direction which will move the spindle 4 upwardly. This upward urging of the spindle 4 exerts a constant pressure on the blank 54 of the tool 58. When the lever I'I'I is operated to move the spindle 4 downwardly the cam sheave I90 is moved to a position illustrated by the dotted lines in Fig. II, whereupon the weight I9I is raised and held in an upward direction. This is by reason of the fact that the cord I92 is moved to a position adjacent the shaft I89 and no lever action on the cam sheave I90 exists.

The front plate I93 of the device has a window opening I94 therein and also has a disc I95 pivotally attached thereto, as illustrated at I96. An operating knob I9! is provided for rotating the disc I95. The disc I95 is positioned internally of the front plate I93 of the device and is located between said front plate and the baffle I80. The disc I95 is provided with a chart I98 having portions thereof rotatable into alignment with the window opening I94. This chart I98 has indicia within the central opening of the base 203 of the main annular portion of the tool. The base 208 of the main annular portion 204 of the tool is joined into the hub I99, as by soldering or the like, along the adjacent surfaces 205. The said soldering may be in the form of a sweating operation wherein only a minimum amount of solder is necessary and whereby only a small amount of heat will soften said solder. The main annular portion 204 is preferably formed of fine particles of metal having a plurality of abrasive particles mixed therewith and held by sintering said particles of metal with each other. The base 208 is preferably formed only of particles of metal while the main abrading portion 204 is preferably formed of particles of' abrasive, such as crushed diamonds, sapphires or the like, distributed throughout the :efiective abrading portion of the tool. It is to be understood that any other suitable bonding material might be used and the particles of abrasive held in said material by means other than sintering, as for example, the said bonding material may be in the form of a plastic having characteristics of methyl methacryl'ate, Bakelite and so forth, or may have cementitious characteristics or the like. The base 203 and main annular portion 204 are so formed as to be in integral relation with each other along an annular intermediate surface 208 which forms a surface of division between the base of the tool formed preferably only of sintered particles of metal and the main abrading portion formed of a mixture of sintered metal and particles of abrasive. The particles of abrasive are distributed throughout the particles of metal or other bonding material of the main grinding element 204 of the tool in such a manner as to increase the thickness of the main grinding element 204 in different directions of greater wear during the use of the tool, as illustrated by the dot and dash lines A and B.

The tool, like the tool 58, is supported for angular movement substantially about the center of rotation 201 of the curvature 208 of the effective abrading surface of' the tool. The tool, during use, is supported to pivot about the center 201 so that the effective abrading surface of said tool may be disposed at different angles, with respect to the work, to change the arc of the thereon which indicates the angle at which the understood that any suitable arrangement may be used for indicating the plus and minus angles.

In Figs. XI and XII there is illustrated a modified form of abrading tool and support comprising a hub I99 having a shank 200 with a tapered opening 20I therein and a. reduced extension 202. The reduced extension 202 is adapted to extend curve generated on said work, with substantially no change in the relation of the work relative to the abrading face of the tool.

Abrading tools of this character are designed to form plus and minus surfaces, that is, concave and convex surfaces. When forming concave or minus surfaces the effective portion of the tool substantially along the dot and dash line A is used. When forming plus or convex surfaces the effective portion of the tool substantially along the dot and dash line- B is used. It has been found from practice that, in the general run of the work, more minus or concave surfaces are required than plus or convex surfaces so that the main grinding or abrading element is increased in thickness along the line A more than along the line B by an amount determined according to the average percentage of surfaces to be formed by the tool so that the said thicknesses are balanced according to the amount of surfaces to be formed thereby and so that each tool will perform its maximum efficiencyboth as regards the generation of plus and minus curvatures prior to the discarding thereof. The tool is so designed that it will not perform the ex- I tent of its usefulness, for example, in forming the abrading machines.

concave or minus surfaces prior to its reaching the extent of its usefulness in forming plus or convex surfaces. In other words when the tool is forming concave or minus surfaces it will readily be seen that the outer and thicker portions of the grinding material will be the portions which come in contact with the lens. Since in normal use in the art the concave surfaces have been found to be in the majority as opposed to the number of convex surfaces which are ground in machines of this type. When convex surfaces are ground by this tool it will be readily understood that the inner portions, or those not so thick, of the grinding material will be in contact with the convex lens. It will therefore be readily understood that the outer portions of the grinding material are built up so as to be able to grind more surfaces than the inner portions so that over a period of time in the normal use of this tool more concave surfaces are ground than convex and the varied thickness of the grinding material of this tool is such that when the limit of the life of the tool has been reached the grinding material will be worn down to the support 203 substantially uniformly throughout its interface therewith. The effective abrading surface of the tool, in order to increase the life and durability thereof particularly for rough curve generation, is built up slightly along the lines A and B, as indicated at 209 and 2l0. These built up portions, although at the start of the use of the tool introduce a slight'error in curvature, are practical for rough or semi-finished curve generation. It has been found that the error introduced by such built up portions 209 and 2| is negligible and can, if necessary, be compensated for during the initial setting up of The built up portions 209 and H0 each have a curved surface thereon of a relatively short radius of curvature, as indicated by the arrows 2H and 2l2. The surfaces 2! and 2| I, which are of relatively short radius of curvature, are joined centrally by a longer radius of curvature, such as illustrated by an arrow H3. The curvature 2l3 is substantially tangent with the arc of curvature 208 along the line ofwhich the effective abrading surface of the tool is moved when the tool is tilted about the center 201. The annular intermediate surface 206 is composed of two differently curved areas, 2 and 2l5. The area 2 is of a relatively lo ng radius of curvature and the area 2l5 is of a relatively short radius of curvature but slightly less than the radius of curvature 2l3.

The hub I99 and the base 203 are provided with an aligned opening 216 whose axis is disposed at an angle relative to the longitudinal axis of the shank 200 of the hub. This opening 2l6 communicates with the recessed area 2" of the main annular portion of the-tool and it is adapted to provide a vent through which lubricant fed into the recessed area 2ll through the hollow shaft 66 may flow outwardly and thereby avoid having an excessive internal pressure built up in said recessed area during the abrading operation.

When the main abrading portion 204 of the tool has become worn and. inefficient for use the said portion may be removed from the base 203 and a new portion secured thereto by the application of heat sufiicient to soften the bonding means holding said main abrading portion 204 to the base 203.

The tool set forth above'theoretically has an abradingsurface lying substantially in the line of the are 208 although during the initial use of the tool the built up portions 209 and 2! do depart slightly from said arc. This slight departure may be compensated for during the setting up adjustment of the machine, if de-:

secured to the hub I99, as by soldering, it is to be understood that it may be secured by other bonding means. I

As the abrading tool wears, and yet retains its abrading surface in the same curvature, it will be understood that the center of curvature 9| will gradually move away from its original position. To compensate for this movement, and

to avoid error in positioning the center of curvature 9| of the abrading surface 59 in axial alignment with the effective pivot 90 of the head 2, a guide mark 2l9 (Fig. 'I) is provided on the head 2 in such a position that, regardless of the wear of the tool, as long as the abrading surface is aligned with the mark 2l8, the tool is in the proper operating position. The guide mark 2"! is positioned on the head 2 a distance from the effective pivot 90 equal to a radius of the'abrading surface 59, and the abrading surface is usually aligned with the .guide mark 2l8 by placing a sharp, flat, tool horizontally on the mark and bringing the abrading surface to rest thereon.

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

Having described my invention, I-claim:

1. In a devicemf the. character described the combination of a hollowhousing having a work supporting spindle rotatably and slidably mounted therein and a head pivoted thereto, said pivot connection having a relatively wide .surface bearing with means associated therewith for locking the head in different angular positions, a tool supporting spindle rotatably mounted in said head having an abrading tool attached thereto and adapted to be tilted through the tilting action of said head to diflerent angular positions with respect to the longi- 1 tudinal axis of the work supporting spindle, said hollow housing having an open wall portion and means for closing said opening for confining the abrading tool and work carried by said work supporting spindle internally of said housing.

2. In a device of the character described the combination of a hollow housing having a work rotatably and mounted therein and a head pivoted thereto, said pivot connection having a relatively wide surface bearing with means associated therewith for locking the head in different angular positions, a tool supporting spindle rotatably mounted in said head having an abrading tool attached thereto and adapted to be tilted through the tilting action of said head to different angular positions with respect to the longitudinalaxis of the work supporting spindle, said hollow housing having an open wall portion,

means for closing said opening for confining the slidably connection having a relatively wide surface bearing with means associated therewith for locking the head in difierent angular positions, a tool supporting spindle rotatably mounted in. said head having an abrading tool attached thereto and adapted to be tilted through the tilting action of said head to different angular positions with respect to the longitudinal axis of the work supporting spindle, said hollow housing having an open wall portion, means for closing said opening for confining the abrading tool and work carried by said work supporting, spindle internally of said housing and means for simultaneously rotating said work and tool supporting spindles.

4. In a device of the character described the combination of a hollow housing having a work supporting spindle rotatably and slidably mounted therein and a head pivoted thereto, said pivot connection having a relatively wide surface hearing with means associated therewith for locking the head in different angular positions, a tool supporting spindle rotatably mounted in said head having an abrading tool attached thereto and adapted to be tilted through the tilting action of said head to different angular positions with respect to the longitudinal axis of the work supporting spindle,- said hollow housing having an open wall portion, means for closing said opening for confining the abrading tool and work carried by said work supporting spindle internally of said housing, means for urging said work supporting spindle towards said tool supporting spindle and means for simultaneously rotating said work and tool supporting spindles.

5. Gauge means for use with an abrading machine of the above character having a tool supporting spindle and a work supporting spindle cooperatively related with each other, and means for urging one of said spindles towards the other,

said gauge means having a spacer portion adapt-- ed to be disposed between the work and an abrading tool carried by said respective spindles for tact adjustable to a relatively set position and a movable contact, means adapted to be positioned between said contacts which is of substantially the same length as the spacer portion for obtaining an initial setting of said movable contact and mechanical means correlating said respective means which are adapted to be posi- :ofthe movable contact for predetermining the amount of material to be removed from the work during said abrading operation. 7

6. Gauge means for use with an abrading machine of the above character having a tool supporting spindle and a work supporting spindle cooperatively related with each other, means for urging one of said spindles towards the other, and means for imparting a rotary movement to said spindles, said gauge means having a spacer portion adapted to be disposed between the work and an abrading tool carried by said respective spindles for positioning said work and tool in positive spaced relation with each other and having automatic stop means for controlling the extent of abrading, said automatic stop means comprising a contact adjustable to a relatively set position and a movable contact, means adapted to be positioned between said contacts which is of substantially the same length as the spacer portion for obtaining an initial setting of said movable contact and mechanical means correlating said respective means which are adapted to be positioned between the tool and work and the contact members for simultaneously moving said means into and out of operative position, scale and indicator means associated with said adjustable contact for controlling the adjustment thereof relative to said initial set position of the movable contact for predetermining the amount of material to be removed from the work during said abrading operation and switch means associated with one of said contacts and adapted to be operated thereby for automatically shutting off the means for driving said spindle.

7. Gauge means for 'use with an abraiding machine of the above character having a tool supporting spindle and a work supporting spindle cooperatively related with each other, means for urging one of said spindles towards the other, and electrically operated means for rotating said spindles having a circuit connection with electrical energy, said gauge means having a spacer portion adapted to be disposed between the work and an abrading tool carried by said respective spindles for positioning said work and tool in positive spaced relation with each other and having automatic stop means for controlling the extent of abrading, said automatic stop means comprising a contact adjustable to a relatively set position and a movable contact, means adapted to be positioned between said contacts which is of substantially the same length as the spacer portion for obtaining an initial 'seting of said movable contact and mechanical means correlating said respective means which are adapted to be positioned between the tool and work and the contact members for simultaneously moving said means into and out of operative position, scale and indicator means associated with said adjustable contact for controlling the adjustment I thereof relative to said initial set position of the movable contact for predetermining the amount of material to be removed from the work during said abrading operation, switch means associated with one'of said contacts and adapted to be operated thereby for automatically shutting off the means for driving said spindle and means for opening the circuit of said electrically operated means when the spacer means is between the work and tool and for closing said circuit when :3: means is moved from between said work and 8. In a device of the character described the combination of a hollow housing having a work supporting spindle rotatably mounted therein and a head pivoted thereto, said pivot connection having a relatively wide surface bearing with means associated therewith forlocking the head in different angular positions, a tool supporting spindle rotatably mounted in said head having an abrading tool attached thereto and adapted to be porting spindle internally of said housing and means for urging one of said work and. tool supporting spindles toward the otherof said spin-.

dies.

9. Gauge means for use with an abrading machine of the above character having a tool supporting spindle and a work supporting spindle cooperatively related with each other, means for urging one of said spindles towards the other, said gauge means having a spacer portion adapted to be disposed between the work and an abrading tool carried by said respective spindles for positioning said work and tool in positive spaced relation with each other and having automatic stop means for controlling the extent of abrading, said automatic stop means comprising a pair of contact members, one of said contact members being adjustable to a relatively set position and the other being movable, means adapted to be positioned between said contact members which is of substantially the same length as the spacer portion for obtaining an initial set position of one of said contact members relative to the other, and mechanical means correlating said respective means which are adapted to be positioned between the tool and work and the contact members for simultaneously moving said means into and out of operative position, and means for adjusting one of said contact members relative to the other for varying the relation thereof as determined by said initial set position for predetermining the amount of material to be removed from the work during said abrading operation. 7

' LLOYD W. GODDU.

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