US2284056A - Lapping machine - Google Patents

Description

May 26, 1942*.` LH. s. IDG

' LAPPING-MAGHINE Filed July 9, 1940 May ze, 1942, www@ Y? 2,284,056

'LAPPING MACHINE Filed July s, 1940 5 sheets-sheet 2 a0 ao "I9 loo 79 38 x f 3Q :B44 4o is u 27 o wb I .2 M) (im I3 New n VH --lz5 1 i 'sa 10o 151 'o1 qe 153 0 gmc/w60@ f E o ..9

Q Y Herber 5. Indge May 26, 1942. H. s. INDGE i LAPPING MAGHNE 5 Sheets-Sheet 3 Filed July 9, 1940 57 'HHL IlIlA Herber 5. Indge wenn' H. s. INDGE l 2,284,056

L APPING MACHINE Filed July 49, 1940 5 Sheets-SheetA v May 26, -1942.

Herbr I ndge 3^# :Humm L. am

May 26, 1942. H. s. INDGE LAPPING MACHINE Filed July 9, 1940 5 Sheets-Sheet 5 -vurlan ,yf/

um 89mg w Herber 5. Indge 32 Muem @1Mo/man Patented May 26, 1942 UNITED STATES PATENT orifice LAPPING MACHINEl Herbert S. Inilge,Westbo1-o, Mass., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application July 9, 194o, s,eria1 No. 344,554

6 Claims.

The invention relates to lapping machines.

, and more particularly to a lapping machine for producing highly rened plane surfaces on a work piece.

One object of the invention vis to provide a simple and thoroughly practical lapping machine in which a plane surface of a relatively large worl; piece may be rapidly surfaced to a plane surface of extremely high quality. Another object of the invention is to provide a lapping machine in which the work piece is rotated and gyrated in a rotary' or irregular path while being lapped or abraded by a plurality of rotary and Work pieces by applying a plurality of lapping elements thereto which are reciprocated with a compound reciprocatory movement and simultaneously oscillated in arcuate paths relative to the surface of the work piece being lapped. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exempliiied in the structure to be hereinafter described, and the scope of the application of which will be indicated in the .following claims.

In the accompanying drawings, in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a right-hand end elevation of the improved lapping machine equipped with rotatable lapping wheels, having parts broken away and shown in section to show the operating mechanism thereof Fig. 2 is a front elevation of the improved lapping machine equipped with reciprocating lapping stick adapters;

Fig. 3 is a fragmentary diagrammatic view, showing the hydraulic piping diagram and electrical control circuit of the machine;

Fig 4 is a fragmentary pian view, showing the driving mechanism for the lapping heads and spindles;

Fig, 5 is a fragmentary vertical sectional view, on anenlarged scale,v of the driving and operating mechanism for one of the lapping heads;

Fig. 6 is a fragmentary cross-sectional view,

taken approximately on the line 6-6 of Fig.,5,' showing the driving mechanism'for producing a slow rotation'of the lapping wheel;`

Fig. V'l isa 'fragmentary bottom view, onV an enlarged scale, havingl parts broken away'and shown in section, lof the reduction gear unitffor controlling the simultaneous oscillation ofthe I lapping heads;

` Fig. 8 is a cross-sectional-view, taken approximately on the 4Ifnet-8 of Fig. 7;

Fig. 9 is a fragmentary sectional view, onan enlarged scale, of the gear mechanism for simultaneously oscillating, the lapping Aheads;

Fig. 10 is a fragmentary view showing the arrangement of the control lever for actuating' the cycle start switch and the stop switch:

Fig. llis a fragmentary vertical sectional view, on an enlarged scale, through one of the lapping heads equipped .with a reciprocating stick adapter;

Fig. 12 isa fragmentary front elevation, on an enlarged scale, showing the reciprocating lapping stickadapter;

Fig. 13 is a cross-sectional view, on an enlarged scaleftaken approximately on the line `I3--I3 of Fig. 11;

Fig. 14 is a fragmentaryv sectional view, on

an enlarged scale,l takenapproximately ony the line I4-I4 of Fig. 11;,and y Fig. 15 is a fragmentary front elevation, showing the two .lapping heads vequipped with lapping wheels.

The improved lapping machine illustrated .in

4the drawings comprises av base l0 whlchsupports a rotatable work supporting platen .II together with a. plurality of work Vdriving pins or studs I2 (only one of which is `shown in the drawings) which engage apertures in a work piece I3 to beflnished. 'The platen Il is'positively driven by means of an electrlcfmotorV Il mounted within the base I0 of the machine. The motor I4 is preferably mounted on a pivotally-mounted adjustable motorysupport l5 (Fig. 1) which is supportedon a stud or shaft I6.

VThe motor I4 is providedv with a driving. pulley I9 which inV turn serves to rotate a worm 20 (Fig. 3). The worm 2U meshes withY a` worm gear 2| Vand serves to drive the work'su.pport` ing platen II and revolve and gyrate the work driving pins I2 by means of a mechanism substantially the same as that shown inmy prior U. s. Patent No. 1,610,527 datedrnecember 14,4

1926. The details of the mechanism for rotating the work supporting platen Il, which in my prior patent is a lapping element II, and for rotating and revolving the work driving pins I2, have not been illustrated in the present case since it is noty considered to be a part of the present invention. For details'of disclosure not4 contained'herein, reference may bc'had to my prior patent above referred to. W

Apairwof spacedflapping heads 25 and 21 (Fig. 2) vare provided for supportingeither a` lapping Wheel or a reciprocating lapping sticky adapter (to be hereinafter described) so as to' present a plane operative end -faceto'lap orv abrade the Work piece I3. In the preferred conare provided Vincluding in addition-to afhead 25 a port for a lapping'wheel 28 -or a reciprocatingl lapping stick `adapter which is 4also arranged to present a plane operative face. The lapping wheels 28 `(only one of Vwhich hasbeen illus'- trated inFigs. l and`3)jare spacedfrom each piece is rotated yandygyrated. Each Vof the Vheads 25and 21 is identical inv construction,

consequently' only one of the ,heals'lhas been illustrated "inf" detail. The lapping `wheel' 28 (Fig. 1) isfsupported at oneend/of aV rotatable spindle 29 which isiournalled in an eccentrically Y 4mounted, bearing 3|! withina rotatable'sle'eve 3|.

The sleeve 3| is rotatably supported in bearings 'of the arms 4| and 42 are each provided with intermeshing gear segments 43 and" by means ofwhich the arms :s ando together with the heads 25 and 21, respectively, and the lapping wheels 26 and 28 may be simultaneously oscillated in opposite directions during the lapping operation to impart a relative oscillating movement to each of the heads 25 and 21 during the struction, a pairl of spacedf micro-lapping heads;`

' ,Y micro-lapping head 21 which serves as a sup#- 'rotary and planetary movement of the lapping' wheels Y supported thereby. l

" The frame 38 has a rearwardly extending portion 48'(Fig. 4) which serves as a support for which is connected by a V-belt 5|-witl multian Velectric driving motor 49. The motor 49 is provided with a driving pulley 5,0 which is preferably a` multistepped v-type pulley (Fig. 1)

ple' stepped v- pulleys 52 and 53. respectively. The pulleys 52 and 53 are supported by vertically l arrangedshafts or spindles 54 and 55, respectively, which arefzrotatably` journalled in the sleeves-4|. A 1 i y i i The spindle or shaft 55 also 'Supports a single Vgroove pulley 56 (Fig.` 4)'which is connected l byaV-belt 51 with a single Vgroove pulley 58 32jand 33 Within the frame of the head 21'.` The wheel"26 is similarly. mounted at the lower end l `of a rotatable( vspiridle which is similarly -jourin a rotatable sleeve whichis in turn rotatably supported within .the frame Yof the head 25.

Both ofthe heads V21 and25 are arrangedv so that the rotatable sleeyes 3| may be rotated at av relatively fast speed whiletheeccentrically mounted'spindles 29 contained therein are rotated at a relatively slowvsped so that the individual abrasive grains ofthe lapping wheels 'i 26 arid28 will be moved in'irregular paths while `in operative contact during the rotaryand gy.-

spindle 29. VThis portion 65'serves `as a support `for ananti-friction bearing 66 Vwhich in turn supports a rotatable sleeve 261.' Vv'Ihe sleeve 61 carries a gear 68 which is xedly mounted thereratory movement'of'the workpiece I3.

i jThe Vlapping heads 25 and 21. are preferably arranged Aso4 that they maybe moved `in asubstantially verticaljdirection toward andfrom the 'work"piecef| 3. vQAhollovv column 36 is rigidly` fixed tothe-upper rsurface lof the base I0. Afvernalledin' eccentrically positioned bearings Withmountedwithinjthe'column 36 and'isarranged Atofsupport `the lapping `heads 25 andj21fadja- 'cent toA its: upper lend. The "sleeve 31; supports 'a bracket 38`whichserves as a support not/only 'for the lapping headsg'25 and 21 but also su-p-v ports `thefdivingmechanism therefor to be here-V "inafte'r, described.` f

4 providing a Vfurther irregularvbreak-up motion of the ,lappingA elements to produce Ya higlr- `ly nished workpiece, KVThe heads 25 and 21 are each` provided with rearwardlyextend-v `which isV mounted on and Vadjacentto the upper end of the sleeve 3| to rotate thesleeve 3| and thereby,v carry the spindle 29 and the lapping wheel28 supported thereby in a plantary path. Similarly, the spindle or shaft 54 (Eig.` 4) is provided witha `single V-groove pulley 59 which is'connectedgby means of a V-belt with a single v-groove: pulley (not shown) which is mounted on the rotatable sleeve supporting the lapping wheel spindle 35 to rotate the sleeve and therebymove thespindle 35 and the` lapping wheelsupported `thereby in` a planetary path. This Vplanetary drive-for the head 25 has not been illustratedin detail, since it is identical to that shown in Fig. 1 for the head 21. v

To facilitate a yrelatively 'slow rotary movement 'ofL the lapping wheels 26 and 28 during .their planetary movement, the sleeve 3| is provided with a reduced cylindrical portion which is concentric with the axisof the wheel toyand which mesheswith a'stationary internal ringgear 69 carriedrby the frame ofthe head 21.r The size of the gear 68 is such that it continuously meshes with the-gear 69Qdurin`g the planetary movement of the spindle 29 as produced by-rotation of its supporting sleeve 3|. flhegear-68 has afsmallernumber of teeththan the fixedgear 69, so that asthe gear 68 revolves within) the :stationary gear 69, the very slow rotarymovement is imparted to the lapping wheel spindle 29 toproduce a lrelatively slowrotary movement ofthe Wheel 28 while it is being moved planetarily at a comparatively'rapid rate.

The s1eeve61is-s1idab1y keyed to the spindle 29 by means of la key 10 so that the'spindlemay be moved in a vertical directionrto applythe desired pressure-'to the' lapping wh'eel 28 while in operative engagement with'the workpiece I3.

The upper endof ther'wheel spindle supports an ing arms 39 and;40, respectively, whichrfare pivotallysupportedgon a sleeve.,A ,4|a (only one `of.which is shownpin detail in. Fig-11)'. The bushing. or's1eeye 4| Vis vertically .arranged and is rotatably supported, vloyf ithe bracket., 38.r The arms 39 and 40"`are preferablyarranged as bell cranklevershaving inwardly projecting; arms 4I anclllZ;` respectively (Fig. 4). The inner ends anti-frictiombearing 312.1.-whiclf1in` turn rotatahlyhsupports the casing 13 havinga 'cover plate 14 xedly mounted thereon. Aco'mpression spring,V 15 fissupported at itslower end by 'meansof a.,stud;16,'xedly mounted on or integrally formed with thecap or cover 14. f The'upper endo f` Vthe spring15 is supported by a reduced cylindrical portion or stud 11 formed at the lower end of the sleeve 18. 'I'he sleeve 1 8 is screw threaded within the upwardly extending housing 19. A nut 80 threaded onto the sleeve 18 serves to lock the sleeve 18 in adjusted position relative to the housing 19, so that after the spring 15 has been compressed as desired it may be locked in adjusted position.

It is desirable to provide a suitable mechanism for raising the wheel spindle 29 vertically to compress the spring 15 and withdraw the wheel 28 from operative contact with the work when desired. As illustrated in Fig. *5, a link chain 82 is fastened at its lower end to the stud 16. The u-pper end of the chain 82 is connected to a` pivotally mounted block 83 which is pivotally supported by means of a stud 84. The

stud 84 is supported on an upwardly extending boss 85 formed integral with the sleeve 18. The bracket 83 is providedwith an actuating handle 86 whereby'when moved in a clockwise direction (Fig. 5), the chain 82 may be pulled upwardly in a vertical direction to compress the spring 15 and thereby raise the spindle 29 and the lapping wheel 28 from operative engagement with the work piece. An identical construction is provided for rotating the wheel spindle 35 and also for raising it in a vertical direction. It is, therefore, deemed unnecessary to duplicate illustration of the constructional details of this head which are clearly shown in Fig. 5.

A driving mechanism is provided 'for oscillating the gear segments 43 and 44 to produce an oscillatory movement of each of the lapping wheels 26 and 26 at a comparatively low rate of speed during their combined rapid planetary and slow rotary movements. A speed reduction unit 90 is driven by meansv of a multi-stepped V- groove pulley 9| (Fig. l) mounted on the lower end of the shaft of the motor 49. A V-.belt 92 drivingly connects the pulley 9| with a multistepped V-groove pulley 93 which is mounted on the lower end of the rotatable driving or input shaft 94 of the speed reduction unit 90. A driven or output shaft 95 of the speed reduction unit 90 is provided with a rotatable plate 96 which is in turn provided with a T-slot 91 (Figs. 1 and 4) which serves as an adjustable crank plate. A connecting rod 98 is connected at one end by an adjustably positioned stud 99 which is adlustably supported within the T-slot 91 by means of which the crank motion imparted to the end of the connecting rod 98 may be varied as desired. The forward end of the connecting rod 98 is connected to a stud |00 which is carried by a bracket |0|. The bracket |0| is xedly mounted on the arm 4| adjacent to gear segments 43 and 44. As the rod 98 is moved endwise, due to revolution of the adjustable crankpin 99, an oscillating movement is transmitted through the pin |00, to the bracket |0|, to oscillate the arm 4| which in turn oscillates the head 25 and the lapping wheel 28. At the same time, through the intermeshing gear segments 43 and 44, the arm 42 is oscillated which transmits a corresponding oscillatory vmovement to the lapping head 21 and the lapping wheel 28. By adjusting the crankpin 99 relative to the plate 96, the length lof the oscillatory stroke of the heads 25 and 21 together with the lapping wheels 26 and 28, respectively, may be varied as desired. It will thus be seen that the heads 25 and 21 together with their respective lapping wheels 26 and 28 are oscillated simultaneously and in opposite directions during l the simultaneous rotary and planetary movement of the lapping wheels 26 and 28.

Any standard speed reduction unit may be employed for reducing the speed `of the motor pulley 9| to a suitable speed for oscillating the lapping heads 25 and 21. As illustrated in the drawings, the speed reducing unit which is employed is of thevtype known as the Heliocentric manufactured by the Universal Gear Corporation of Indianapolis, Indiana. The driven or input shaft 94 carries a pair of eccentrics |05 and |06 (Fig. 8). The output or driven shaft 85 is fixedly mounted to a, rotatable plunger holder |01 which travels within a stationary internal rack or gear member which is preferably divided into two parts, namely, the internal racks 08 and |09. The plunger holder |01 rotates within the stationary racks |08 and |09 at the rate of one tooth for each rotation of the input shaft 94.

The plunger holder |01 is slotted radially and carries a plurality of reciprocable plungers ||0 and which are arranged to work into and out of the teeth of the stationary racks |08 and ring gear but with definitely differing toothv shapes, the teeth of the racks |08 and |09 being substantially wedge-shaped. Due'to the wedging contact between the arrow-pointed plungers ||0 and and the teethof the racks 08 and |09, respectively, a combination of Vsliding and rolling Wedge action is obtained, forcing rotation with a minimum friction to the plunger holder |01 and the output o r driven shaft 95. The input eccentrics |05 and |06 force plungers out under load. A pair of retractingrings I|2 and ||3 ride in notches formed within the plungers ||0 and respectively, to hold them back on the no load part of their cycle of operation.

A single eccentric and set of plungers and stationary racks may be employed but for a maximum smoothness of operation and balance of the working parts, a universal Heliocentricspeed reduction unit is employed, having two eccentrics as illustrated, each of which actuates a set ot'4 plunge'rs and in operative engagement with a pair of stationary racks. Each set of plungers is timed directly opposite or 180 degrees apart and has a carrying arc of approximately 120 degrecs. The total effect is a balanced distribution of driving power over two-thirds of the complete cycle so that a balanced and uniform slow rotation of the loutput or driven shaft serves to rotate the eccentric or crankpin 98 to oscillate the heads 25 and 21 simultaneously in opposite directions to cooperate with the combined rotary and planetary movementsl of the lapping wheels 26 and 28 (Fig. 15) to produce the desired breakup movement of the lapping elements, thus producing a highly refined surface on a work piece.

To facilitate removal of nished work pieces and the insertion of work pieces to be lapped into the machine, a power operated lift mechanism is provided whereby the lapping heads 25 and 21 may be simultaneously moved to and from an operative position. In the preferred form, a fluid pressure operated mechanism isemployed, cornl 31 ismoved vertically in an -upward direction to raise the head 38 which in turn raises the lapy azsgote ping heads 25 and 21 and also theI lapping wheels 26 and 28, respectively, to an inoperative position.` Similarly, when uid under `pressure is ad-` mitted to a cylinder chamberV above the pisten IIB, a downward movement ofthe sleeve 31,

Withinthe column 35 is obtained, -thusnioving the lapping heads and 21ftos'l'iift the lapping wheels26 and 28 into operative engagement with the work piece I3. I l

In order to counterbalance the weight ofV the y head 38 andthe -partssupported thereon, a'counrelative to the column 31, the compression of the spring |2I may be adjusted as desired. The com,- pression spring |2I is preferably designed and adjusted so that its compression is sufficient subvalve |40 is provided in the pipe line |28 whereby excess uid under pressure within the iluid system may be exhausted through a pipe |4 into the reservoir |25. g i' "Io facilitate control ofthe lapping operation, anelectrical control `apparatusis provided 'for controllingnotoly the rotation andl gyration of the work piece |3 but'also the rotary, `plane tary; and i oscillatory 'movements of vthe lapping wheel 2E. The valve |30 is preferably `electricallyactuated by means of a solenoid ,|42 which is operatively connected to the left-hand end of the valve stem |3|' and a solenoidv |43 which is operatively connected .to the right-hand end `of the valve stem |3l. j Y

Electric` power pis supplied from a suitableV source of power, indicated'by the power lines |50r (Fig. 3),. An electrlcstarter button |5| is provided to ystart the lapping cycle and a stop button|524 is provided whereby the cycle may be stopped and the laps returnedto an inoperstantially to counterbalance the weight of the head 38 and the mechanisms supported thereby.

' `Whenthe head 38 ismoved downwardlyunder the influence of fluid under pressurethe spring |2| is,compressedand'serves as a cushion to reduce or'cushionthe approaching movement of the lappingv wheels 26 and 28 as they move into operative' contact with the work piece |3.

A fluidjpressure system` is provided for controlling the admission of uid under pressure tothe ncylinder, `||,5. `A reservoir |25 is formed as a separate unit `at therearof the base I0 of the machine and is connected to the base by a large tubular member |26 (Fig. 1).. Fluid is pumped from the'reservoirv |25 by a fluid pump |21 which is driven by an electric motor |28.The pump |21 forcesy fluid under pressure through a pipe |29 to a controlvalve |30. The control valve is a piston typevvalve comprising av valvestem |3| having formed integrally therewith valve pistons |32 and |33-' In the-position of the p arts (Fig. 3), uid under pressure passing throughY the pipe |29 enters a valve chamber located between the valve pistons |32 and |33 and passes outwardly throughV a pipe |34 into the cylinder chamber IIS to move the piston ||6 up-V ative position Vat any time during the cycle, if desiredt.V The push buttons, 5| and |52 are preferablyoperated by means of a manually operable lever |53 (Figs. 1, 2 and 10) which pro-` jects from the front of the machine base I0. The lever |53 is pivotally mounted on a stud |54 which is lixedlymounted within the` baseY l0 and the push buttons*I |5I` and |521 are located within` therbase |0 of the machine. When the leverV |53 is moved in a counterclockwise direction (Fig. 10), the push button switch I 5I is closedwhich serves to energize the solenoid |42 to shift the control valve |30 vtoward the left (Fig. 3) to cause a downward movement ofthe piston` I 8 and the lapping heads 25 and 21 together with their respective lapping wheels 28 and 28, and at the same timeto set an electric time delay relay |55 in motion. i

The downward movement of the head 38 shifts an adjustable stop or dog |56 (Fig. 3) into engagement withV the actuating roller of the normally open limit switch |51 to close the switch which inturn closes a circuit through a magnetic switch |58 to start the motor I4 and thereby rotatevand/or gyrate the work piece I3 and at the same time startthe motor 49 so as to rotate,

revolve and oscillate the lapping wheels 281:0` produce the desired and predetermined lapping operation on the work piece |3. The lappingoperation continuesl forl a predetermined time interval according to `the setting of the adjustable electric `time delay relay |55. After a predenerminedftime interval has lapsed, the time delay relayv |55 serves tov energize the solenoid thus moving the lapping heads 25 and `21 together with their'respective lapping wheels 28 valve chamber between the valve pistons |32 and y |33 passes. outwardly through the pipe Y|35 into the cylinder chamberi|20 to produce .a downward movement of the piston .||6 against the,4

compression `ofthe spring` |2Ito move the bracket 38, lapping heads 25 and 21, and lapping wheels 26 and 28 into operative lapping engage- |38 at the right-handend of the valve |30 (Fig.

3), and out through a pipe |39 which exhausts into the reservoir |25. An adjustable relief and 28 to I an upward or inoperative position. During this upward movement of the head 38, the adjustable stop ordog |56 recedes fr om engagement with' the limit switch |51 and .the switch |51 opens the circuit to operate the contact |58 which in turn stops the motors 4 and 49 to stop the movement of the work piece AI3 gaseoso able. in order to attain` one object of this 111;

vention, it iisfdesirable to provide alapping maichine i11j1`-which either a rotaryplanetarily moved lappingfwheel or a reciprocatory lapping stick rliayabav employed; depending upon the nature of the work--pieces`to be lapped: The lapping wheels226'; and 28 are preferably supported by a tapered shank |60 which mates with or nts a tapered Vaperture .|6|, formed within-.the lower end of the spindles 2 9 and 35,.` respectively, so that the rotatable planetarly lmovable rlapping wheels 28 and26 maybe readily removed from the` machine when desired;

A reciprocatory lapping stick adapter |62 is provided having a hollow tubular shapedjmember provided with an aperture |63'whieh ts anouter peripheral cylndricalcsurface onA the housing 21".V The adapter |62 -isprovided with elongated slots |64 andv |65 which are arranged on `diametricallyopposite sides thereof. A pair of studs |66 and v|61 pass through the elongated I slots` '|64 and' |65, respectively, and are screw threaded into' vthe housing 21. A'thrust collar |68vis .provided adjacent to the lower end of the housing 21 rand a plurality of studs `|69 r(Figs.-

11 and 13) project downwardly 'fromthe thrust collar-|68; The vstudsy|69 are surrounded by compression springs |10,- the lower ends of which arelocated within apertures.'` or holes |1| formed in theadapter |62. In the preferred form'a pluralityof-'studs'l69 are provided which are 'symmetrically-arranged (Figjl) so as to'form a yielding :device whereby the' reciprocable lapi-v ping sticks to befhereinafter described may be maintained inoperative yielding contact `with" the surface ofthe work lpiece I3 to belappe'd.'

The adapter |62 is provided witl'r'a reciprocable lapping stick4 holder if 13 jwhich serves as a support for `a' pair -of spaced' parallel lapping sticks |14"v and |15. Eacliof the lapping vsticks is 'ref movably supported;'dii-l` the reciprocable holder 'Y |13 so that tlne'yfrirayvr be readily removed and replaced'whendesired.. The lapping stick |14 is provided with a' holder |16 having "a surface |11 (Fig. 12) whichmates'with a correspondingly shaped surface onthe under sidef of the reciprof cable -holderv |132v The .holder k|16 isyieldingly' held 'in `position v'on the reciprocable; holder |13 by niearisoffztpairrofl springs |1811. and |18,^re spectively,l by vmeans of which the r lapping stick holderv |16maybereadily detachedwhen it is desired to'replace the vlapping stick with a new stick or'a stick having differentabrading characteristics. Y y i ff w Similarly, the 'lapping stick |15 is mounted in a holder vIlm-whichV is similarly yieldably held in f position onv the reciprocable holder- |13 in the same manner that thelappinglstick |14 and its supporting rholder |16 are mounted. Only one of the mountings has-been shown in detail; since they are identical in construction andit is not deemed Vnecessary Ito duplicatethe illustration. The reciprocable holder' |13 is arrangedto reciprocate longitudinally in a guideway A| 8| formed in a lower end plate |82 fixed to thelower surface of the adapter |62. A member |83 is fixed to the upper surface of the lreciprocable holder |13 `and formsa slidev member which mates'w'ith the slide surface |8| and also slides longitudinally on 'the plate |82, thuscooperating with thereciprocable holder |13 to form slideways for producing-the Vdesired 'reciprocatory movement of the lapping sticks"|14 and |15.

In order to impart a reciprocatory movement to the lapping sticks |14 and |15, a suitable connection is provided between the spindle 29 and the reciprocable lapping stick Vholder |13. kThe Vmember |83 is provided with a transversely extending cut-out portion, forming two thrust surfaces |84 and V|85 (Fig. 14) Within which a ring |86 islocated. The ring |86 serves as a support for an anti-friction bearing |81. A tapered shank |88 mates with the tapered aperture |6| in the lower end of the spindle 29. A crankpin `|821 is formed integral with the shank member y|88 and nts within the central aperture inthe anti- 1` friction bearing |81. It will be readilyapparent from the foregoing disclosure thatl when the spindle 29 is rotated,l the crankpin |89 will be e revolvedto impart a reciprocatory movement to and the spindle29 at a comparatively slow rate of speed, `a compound reciprocatory movement will beV transmitted to the lapping sticks |14 and 59 ducing a plurality of compound motions which v |15. VThe rapid rotation of the sleeve 3| will impart a'comparatively rapid reciprocation of `a relatively long stroke to the lapping sticks |14 and |15 `and simultaneous therewith the slow rotation of the spindle 29 will impart a reciprocatory movement tov the lapping sticks |14 and |15-`Which is of a relatively slow speed through a Icomparatively short stroke. It will be readily apparent from the foregoing disclosure vthat the reciprocatory lapping'sticks |14 and |15 will be provided with a compoundreciprocatory stroke which'4 produces a break-#up'action in abrading or lapping a workpiece. In addition to the compound reciprocatory strokejof the lapping sticks |14 and |15, the two heads 25 and 21 are oscillated simultaneously and in the opposite direction,l thus imparting a third relative motion of theflapping sticks |14 and |15. At the'salme time the compound reciprocatory and oscillating movement is imparted to the lapping sticks |1,4and |15,` the work piece I3 is rotated and gyrated through an irregular path, thus probreaklup theaction Aol? the individual abrading particles of the lapping sticks so as to produce a highly refined ultra-iinished surface on the work piece |3 being lapped.

It will be readily apparent from the foregoing disclosure' that the reciprocable lappingA stick adapter |62 may be readily mountedon the heads 25 and 21 by removing the lapping lwheels 26 and 28 and sliding the tubular members'of the ref ciprocable lapping stick adapters |62 into supporting engagement-.with the housings 25 and 21,* after which the studs |66 and |61 are inserted in place, thus holdingthe adapters |62 in position `for aflapping operation.` WhenV the adapters |62 arev removed intoan operativeposition, the tapered shank |88 is moved into operative engagement with the tapered aperture |6| so that the combined rotary motion of the spindle 29 and the planetary motion of the sleeve 3| will be imparted to produce a compound reciprocatory movement of the lapping sticks |14 and |15. Similarly, the adapter |62 may be readily removed from the machine by removing the studs |66 and |61 and withdrawing the requiring .correction as follows: In the drewings, insert the figure CERTIFICATE OF CORRECT ION."

Patent No. 2,28u,o56. Mayae, letz.

. HERBERT s. INDGE.

It is hereby certified that error appears in the above numbered patent shown helow as a part of Sheet 2 same Sheet 2, Figure 2, for the reference numeral "160" read l60a-; Sheet 5 of the drawings, Figure l2, for the numeral "177" designating a springread -l78a; and that the saidLetters Patent should be read with this 'correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 11th day of August, A. D. -19LL2.

l Y Henry Van Arsdale',

(Seal) Acting Commissioner of Patents.

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