US2272974A

US2272974A - Microlapping machine

Info

Publication number: US2272974A
Application number: US287985A
Authority: US
Inventors: Herbert S Indge
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1939-08-02
Filing date: 1939-08-02
Publication date: 1942-02-10
Anticipated expiration: 1959-02-10

Description

Feb. 10, 1942. H. s. INDGE 2,272,974

MIcRoLAPPING MACHINE l Filed Aug. 2,A 1959 4 Sheets-sheet 1 'Mmmm Feb. lo, H. S. INDG MIGROLAPPINQ MACHINE f Filed'Aug. 2, 1939 4 sheets-sheet 2 HEHHEH T .5T f/VDBE Figi@ Feb. 10, 1.942.

H. S. INDGE MICROLAPPING MACHINE 4 sheets-sheet 5 Filed Aug. 2j 1939 Fly@ HERER 7' EIA/05E @Mum Feb. 10, 1942. H55. lINDGE:v 2,272,974

' MICROLAPPING MACHINE Filed Aug. 2, 1959 4 sheets-'sheet 4 ma 3m. 5 m, m

iwf/ m Patented Feb. 10, 194,2I

MICROLAPPIN G MACHINE yHerbert S. lndge, Westboro, Mass., asslg'nor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application August 2, 1 939, Serial No. 287,985

` 1o claims. (Cl. 51-120) The invention relates to micro-lapping machines, and more particularly to a micro-lapping machine for surfacing plane surfaces.

One object of the invention is to provide a simple and thoroughlypractical micro-lapping machine in which a plane surface of a relatively -large work piece may be rapidly surfaced to a plane surface of an extremely high quality. Another object of the invention is to provide a mimachine; 4

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

Fig. 4 is a fragmentary planview of the ma-A chine, showing the driving mechanism for the micro-lapping heads and wheels;

Fig. 5 -is a fragmentary vertical sectional view, on an enlarged scale, of thedriving and operating mechanism for oneof the lapping heads;

Fig. 6 is a fragmentary cross-sectional view, taken approximately on the line 6 6 of Fig. 5, showing the drive mechanism for producing a slow rotation of the lapping wheel;

cro-lapping machine in which the work piece is 10 Fig. 7 is a fragmentary bottom View, on' an rotated and gyrated in a rotary or irregular path enlarged scale, having parts broken away and while being lapped or abraded by a plurality of shown in section, of the reduction gearA unit for rotary and planetarily moved lapping elements. controlling the simultaneous l'oscillation of the Another object of the invention is to provide a micro-lapping hea-d'5; micro-lapping machine for finishing aplane sur- Fig. 8 is a cross-sectional view, taken approxface by means of a lapping element which is roimately on the line 8 8 of Fig. 7, sli'owing detated slowly and oscillated rapidly in a plane tails of construction of -the speed reduction unit; tary or orbital path. Fig. 9 is a fragmentary sectional view, on an Another object of the invention is to provide enlarged scale, of the gearmechanism for simula micro-lapping machine for nishing a relative-- taneously oscillating the micro-lapping heads; ly large .diameter work piece by applying a pluand rality of slowly rotating, rapidly oscillating lap- Fig.l 10 is a fragmentary view showing the arping elements which are bodily and simultanerangement of the control leverfor actuating the ously oscillated in arcuate paths relativento the cycle stai-.i-l switch and the stop switch. surface of the work piece being finished. A furz5 The improved micro-lapping machine has been ther' object of the `invention is to provide a millllsated 111 the dl'aWiIlgS. COIIIDIiSng a base cro-lapping machine having a plurality of mi- A-Ill, which' suppo'rts a rotatable work supporting cro-lapping heads each of which is pmvided with platen Il together with a plurality of work drivan independent electrically driven lapping eleing pins or studs i2 (only one of which is shown ment which is rotated and gyrated in a plane- 30 in the drawings) Which nage the apertures tary or orbital path and in which the lapping in a work piece It to be finished. 'Ihe platen heads are bodily and Simultaneously moved in Il is positively driven by means of an electric arcuate paths across the face of the surface bemoto( .I4 mounted W1th1f 1 the base I. 0f the ing nished. Other objects will be in part ob- Imwhm The motor I4 1s preferably mounted vious or m part pointed out hel-emanen 35 on a pivotally mounted motor support 5 which The invention accordingly 'consists in the fea- 1S SguDPOled on a stud orshaft I6. The motor y tures of construction,combinations of elements, 'vggg Vlt' grvlvgrg! guei'lg ggg; and arrangements of parts' as Wm be exemphmeshes with a Worm gear 2| and serves to drive edin the structure to be hereinafter described,

40 the work supporting platen Il and revolve and and the scope of the application of which will gyrate the Work driving pins I2 by mea-ns of a be mdlcated m the -ouowmg .cla'lm' mechanism substantially the same as that shown In the accompanymg dla'wmgs m which s in my prior U S Patent No. 1,610,527 dated Deshown one .of various posslble. embodiments of cember 14,192.6. u The details ofl the mechanism the-mech-amca1 features of this inwinnen' 45 for rotating the work supporting platen Il, which Fig' 1 1s a' right'hand end elevatilon' having in my prior patent is a lapping element, and for parts broken away and shown m section to more rotating and revolving the work driving pins I2. Clearly Show the improved micro'lappng ma'. h'ave not been illustrated in the present case, Chine: since 'it is not considered to be a part of the Fig. 2 is a frontelevation of the vimprove 50 present invention Fmdtajls of disclgsure not contained herein, reference may be hadl to my prior patent above referred to.

A nuoro-lapping head is provided for supporting a lapping wheel so as to present a flat operative end surface to abrade the work piece I3. In the preferred construction; a pair of spaced micro-lapping heads are provided including in addition to the head 28 a micro-lapping head 21 which -serves as a support for a microlapping wheel 28 which is also arranged to present a fiat operative face. The lapping

wheels

28 and 28 are spaced from each other and are arranged to engage th'e work piece I3 to be lapped at diametrically opposite positions.

Each 'of the

lapping wheels

28 and 28 are :mounted for both a rotary and a planetary movement so that the abrading or lapping surface is moved in an irregular path as the work piece is rotated and gyrated. Each of the

heads

28 and 21 are identical in construction. Consequently only one of the heads has been illustrated in detail. The lappingwheel 28 (Fig. 1)

is supported at one end of a rotatable spindle 28 ping wheel spindle contained therein is rotated at a relatively slow speed,l so that the individual abrasive grains in the lapping wheels 28 and -28 will be moved in irregular paths while in operative contact with the longitudinally movable rotatable work piece I3 to be finished.

The

lapping heads

28 and 21 are preferably arranged so that they may be moved in a substantially vertical direction toward and from the work piece I3. A hollow column 38 is rigidly fixed tothe upper surface of the base M8. A verticallyv movable hollow sleeve 31 is slidably mounted within the column- 33. and is arranged to support the

lapping heads

28 and 21 adjacent to its upper endl The sleeve 31 supports a bracket 38 which serves as a support not only for the

lapping heads

28 and 21 but also supports the driving mechanism therefor.

In the preferred construction, in addition to the rotary and planetary movement 'of each

lapping wheel

28 and 28,-it is desirable that the heads- 28 and 21 be simultaneously oscillated to impart a third movement to the lapping wheels. thus-aiding in producing a highly refined microilnished surface. The

heads

28 and 21 are each provided with rearwardly extending

arms

38 and 48 respectively which are pivotally supported on a sleeve 4I (only one of which is shown 'in detail in Fig. 1). The bushing or sleeve 4I is vertically .arranged and is rotatably supported by the bracket 38. The

arms

38 and 48 are preferably arranged as bell crank levers having inwardly K projecting arms 4I and 42 respectively (Fig. 4).

The inner ends of the arms 4I and 42 are each 4provided with intermeshing

gear segments

43 and 44 by means of which the arms 38 and 4II together with the

heads

28 and 21, respectively,` and the lapping wheels 28 and` 28, respectively,

' thereby. The frame 38 has a rearwardly extenlding p0r- 78 tion 48 (Fig. 4) which serves as a support for an electric/driving motor 48. Thejmotor 48 is providedwith a pulley 88 which is'preferably a multi-stepped V-type pulley (Fig. -l) which is connected by a V-belt 8l with multi-stepped V-

pulleys

82 and 83, respectively. The -

pulleys

82 and 83 are supported by shafts or spindles 84 and 88, respectfully,

The spindle or shaft 88 also supports a. single V-groove pulley 88 (Fig. 4) which is connected by a V-belt 81 with a single V-groove pulley 88 which is mounted on the upper end of the sleeve 3|. to rotate .the sleeve and thereby carry the spindle 28 and the lapping wheel 28 supported thereby in a planetary path.

Similarly, the spindle or shaft 84 (Fig. 4) is provided with a, single v-groove pulley 88 which is connected by means of a V-belt 88 with a single V-groove I pulley (not shown) which is mounted on the rotatable sleeve supporting the lapping wheel spindle 38 to rotate the sleeve and thereby move the spindle 38 and the lapping 'I wheel supported thereby in a planetary path. This planetary drive for the head 28 has not been illustrated in detail, since it is identical withthat shown in Fig. 1 for the head 21.

To facilitate a relatively slow rotary movement of the lappingwheel 28 during its planef tary motion, the sleeve 3I is provided with a reduced cylindrical portion 88 whichv is concentric with the axis of the wheel spindle 28.. -This p0rvtion 88 servesas a support for an anti-friction bearing. which in turn supports a rotatable sleeve 81. The sleeve 81 carries a gear 88 which is fixedly mounted thereto and which meshes with a stationary internal ring gear 88 carried by the frame of the head 21. The size of the gear 88 is such that it continuously meshes with the gear 88 durlngthe planetary movement of the spindle 28 as produced by rotation of its supportvery slow rotary movement is imparted to the lapping wheel spindle 28 to'produce a relatively slow rotary movement of the wheel 28 while itis being moved planetarily'; at a comparatlvelw rapid rate.

The sleeve 81 is slidably keyed to thespindle 1 28 by means of a key`18 so that the spindle 28 may be moved in a vertical direction to apply the desired pressure to the lapping wheel while in operative engagement with the work piece I3. 'Ihe upper end of the wheel spindle supports an anti-friction bearing 12 which in turn rotatably supports the casing 13 having a, cover plate 14 xedly mounted thereon. A compression spring 'I8 is supported at its lower end by means of a v stud 18 ilxedly mounted on or integrally formed with the cap or cover 14. The upper end of the spring 18 is supported by a reduced cylindrical portion or stud 11 formed at the lower end of a sleeve 18. The sleeve 18 is screw threaded within the upwardly extending housing 18. A nut 80 threaded onto the sleeve 18 serves to-lock the sleeve 18 in adjusted position relativel to the' housing '18,y so that after the spring 18 hasbeen tensioned as desired it may be locked in adjusted position. 1.

It is desirable to provide a suitablemechanism for 'raising the wheel spindle 28 vertically to compress the spring 18 and withdraw the wheel 28 from operative contact with the work when desired. As illustrated in Fig. 5,' a link chain 82 which are rotatably journalledl within the sleeves 4I.

is fastened at its lower end to a stud 16.l The upper 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 provided with an actuating handle 86 whereby when moved in a, clockwise direction (Fig. the chain 82 may be pulled upwardly in a vertical direction to compress the spring and thereby` raise the spindle 29 and the lapping wheel 28 from operative engagement with the workpiece.

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 e the

gear segments

43 and 44 to produce an oscillatory movement of each of the lapping

wheels

26 and 28 at a comparatively low rate of speed during their comparatively rapid planetary and slow rotary movements. A speed reducing unit 90 is driven by means of a multistepped V-groove pulley 9| (Fig. 1) mounted on the lower end of the shaft of the motor 49. A V-belt 92 drivingly connects the pulley 9| with a ymulti-stepped V-groove pulley 93 which is mounted on the lower end of a rotatable driving shaft 94 of the speed reducing unit 90. A driven shaft 95 of the speed reducing unit 90 is provided with a rotatable plate 96 which is provided with a T-slot 91 which serves as an adjustable crankl plate. lA connecting rod 98 is connected at one end by an adjustably positioned stud which is adjustably supported within the T-slot 91 by means" of which the crank motion imparted to. the end of the connecting rod 98 may be yvaried 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| (Fig. 9) adjacent to the

gear segments

43 and 44. As the rod 98 is moved endwise due to the revolution of the adjustable crankpin 99, an oscillating movement is transmitted through the pin |00, to the bracket |0l, to oscillate the arm 4| which in turn oscillates the head 25 and the lapping wheel 26. At the same time, through the

intermeshing gear segments

43 and 44, the.

arm 42 is oscillated which transmits a correspending oscillatory movement to the micro-lapping head 21 and the lapping wheel 28. By adjusting the crankpin 99 relative to the plate 96, the oscillatory movement of the heads 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 2,1 together with their

respective lapping wheels

26 and 28 are oscillated simultaneously and in opposite directions during the 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

wheels

26 and 28. As illustrated in the drawings, a speed reducing unit is employed, of the type known as the Heliocentric, manufactured by Universal Gear Corporation of Indianapolis, Indiana. The driven or input shaft 94' carries a pair of eccentrics |05 and |06. The rotatable output or driven shaft member 95 is |01 which travels within a stationary internal gear or rack member which is preferably divided into two parts, namely the internal annular racks within the stationary racks |08 and |09 at the rate of one rack tooth for each rotation of the 4input shaft 94. The plu-nger holder |01 is slotted radially and carriesa plurality of reciprocable plungers ||0 and which are arranged to work into and out of theteeth of the stationary racks |08 and |09. The racks |08 and`|09 are keyed to the casing and have the general appearance of an internal ring gear but with denitely differing tooth shapes, the teeth of the racks |08 and |09 being substantially wedge-shaped. Due to the working contact between the arrow-pointed plungers ||0 and and the teeth of the racks |08 and |09, respectively, a combination of sliding and rolling wedge action-is obtained, forcing rotation with a minimum friction to the plunger holder |01 and the output or driven shaft 95. The input eccentrics |05 and |06 force plungers out under load. A pair of retracting rings ||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 working parts, a universal Heliocentric reducer isemployed, having the two eccentrics as` illustrated, each of which actuates a set of plungers fixedly mounted to a rotatable plunger holder and in operative engagement with a pair of stationary'racks. Each set of plungers is timed directly opposite or 180 apart and has a carrying arc of approximately 'Ihe total eiect is a balanced distribution of driving power over two-thirds of the complete cycle so that a balanced and uniform slow rotation of the output' Iproduce a micro-finished surface of high quality.

. To facilitate removal of finished work pieces and insertion of work pieces to be lapped, a power operated lift is provided whereby the micro-lapping heads 25 yand 21 may be simultaneously moved to and from an operating position.` In the preferred form a uid pressure operated mechanism is employed', comprising a cylinder ||5 which is xed relative to the base I0 of 'the machine. A piston ||6 is slidably mounted therein and is connected to one end of a piston rod ||1. The upper end of the piston rod ||1 is connected to an end cap ||8 which is fixedly mounted on the upper end of the sleeve 31. When fluid under pressure is admitted to a cylinder chamber I|9 below the piston H6, t'he piston ||6 together with the sleeve 31 is moved vertically to raise the head 38 which inturn raises the micro-lapping heads 25 and 21 and the lapping

wheels

26 and 28 respectively to an inoperative position. Similarly, when iiuid under pressure is admitted to a cylinder chamber |20 above the piston, a downward movement ofthe sleeve 31 within the column 36 is obtained, thus moving the lapping heads 25 and 21 to shift the lappingr wheeis 26 and 28 into operative engagement with the work piece |3. i

In order to counterbalance the weight of the head 38 and the parts supported thereon, a counterbalance. spring |2| is provided. The spring |2I is a compression spring and surrounds the piston rod I I1 and is contained within a central aperture in the vertically movable sleeve 31 and is interposed between a plate |22 at the base of the column 36 and an .adjustable thrust collar or nut |23 which is screw threaded into a threaded aperture at the top of the column 31. By adjusting the nut |23 relative to the column 31, thecompression of the spring |2I may be adjusted as desired. The compression spring |2I is preferably designed and adjusted so that its compression is suflicient to substantially counterbalance the weight of the head 38 and the mechanism associated therewith and mounted thereon. When the head 38 is moved downwardly under the influence of fluid' under pressure, the spring is compressed and serves as a cushion to slightly reduce or cushion the approaching movement of the lapping

wheels

26 and 28 as they move into operative contact with the work piece I3.

A fluid pressure system is provided for controlling the admission of fluid under pressure to the cylinder II5. A reservoir |25 is formed as a separate unit at the rear of the base I of the machine and is connected to the base by a large tubular member |26 (Fig. '1). Fluid is pumped from the reservoir |25 by `a. fluid pump |21 which is driven by an f electric motor |28. The pump |21 forces fluid under pressure through a pipe |29 to a control valve |30. The control valve |30 is preferably a piston type valve comprising a valve s tem |3| having formed integrally therewith valve pistons |32 and |33. Inthe position of the parts as illustrated in Fig. 3, uid under pressure passing through the pipe I 29 enters a valve chamber located between the valve pistons |32 and |33 and passes outwardly through a pipe |34 into the cylinder chamber ||9 to move'the piston I 6 upwardly which in turn serves to move the lapping heads and 21 to an upward or inoperative position. During this movement, fluid within the cylinder chamber |20 is exhausted through a pipe |35v which passes fluid into an end chamber |36 in the valve |30, from which uid exhausts through a pipe |31 into the reservoir |25. v

When the valve stem I3| is moved toward the left (Fig. 3) into its reverse position, uid under pressure from the pipe |29 entering the valve chamber between the valve pistons |32 and |33 passes outwardlythrough the pipe |35 into the cylinder chamber |20 to produce a downward movement of the piston I6 against the compression of the spring |2| to move the head 38, lapping heads 25 and 21, and lapping

wheels

26 and 28, respectively, into operative lapping engagement with the work piece I3. During this movement, fluid within the cylinder chamber I|9 is exhausted through the pipe |34, into a chamber |38 at the right-hand end of the valve |30 (Fig. 3), and out through a pipe |39 which exhausts into the reservoir |25.

A relief valve |40 is provided in the pipe ,line- |29 whereby excess fluid under pressure within the system may be exhausted through a pipe I4I intov the reservoir |25.

To facilitate control of thelapping operation, an electrical control apparatus is provided for controlling not only the rotation and gyration of the work piece I3 but also the rotary, planetary, and oscillatory movement of the lapping

wheels

26 and 28, respectively. The valve |30 is preferably electrically actuated by means of a solenoid |42 which is operatively connected to the left-hand end of the valve stem |3| and a solenoid I 43 which is operatively connected to theA right-hand end of the valve stem I3I.

Electric power is supplied from a suitable source of power, indicated by the power lines (Fig-3). An electric starter button |5| is provided to start the lapping cycle and a stop button 52 is provided whereby-the cycle may be stopped and the laps returned to an inoperative positionat any time during the cycle, if desired. The push buttons |5| `and |52 are preferably operated by means of `a manually operable lever |53 (Figs. 1, 2 and 10) which projects from the front of the machine base I0. The lever |53 is pivotally mounted on a stud |54 which is xedly mounted within the base I0, and the push buttons |5I and |52 are located within the base I0 of the machine. When the lever |53 is moved in a counterclockwi'sedirection (Fig. 10), the push button switch' I5| is closed which serves to energize the solenoid |42 to shift the control valve |30 toward the left (Fig. 3) to cause a downward movement of the piston |I6 and the lapping heads 25 and 21 and their

respective lapping wheels

28 and 28, and at the same time to set thetime delay relay |55 in motion. The downward movement of the head 38 shifts an adjustable stop or dog |56 (Fig. 3) into engagement with the actuating roller of a normally open limit switch |51 to close the switch |51- which in turn operates through a contact switch |58 to start the motor I4 and thereby rotate and/or gyrate the work piece I3 and at the same time start the motor 49 to rotate, revolve, and oscillate the lapping

wheels

26 and 28, respectively, to produce the desired and predetermined micro-finishing operation on the work piece I3. 'I'he lapping operation continues for a predetermined time interval according to the setting of the adjustable electrical time delay relay |55. After a predetermined time interval has elapsed, the time delay relay |55 serves to energize the solenoid |43 to shift the valve |30 toward the right (Fig. 3) to cause the piston II'6 to move upwardly to move the lapping heads 25 and 21 together with their respective lapping wheels 26 'and 28 to an inoperative position. During this upward movement of the head 30, the adjustable stop or dog I 56 recedes from engagement with the limit switch 51 and the switch |51 opens the circuit to operate the contact with |58 which in turn stops the motors I 4 and 49 to stop the movement of the work piece I3 and the lapping

wheels

26 and 28 so that the finished work piece may be removed from the machine and a new piece to be lapped inserted thereinstead.

A push button switch |60 is mounted on the front of the machine base tov control the starting and stopping of the motor |28 which drives the fluid pump |21.

The operation of this machine will be readily v apparent from the foregoing disclosure. A work piece I3 is placed in operating position on thework supporting platen II, and the push button |60 is then'actuated to start the fluid pump motor |28. The control knob |53 is then shifted toward the right (Fig. 2) or in a counterclockwise direction (Fig. l0) to actuate the starter switch so that the micro-lapping heads' 25 and 21 together with their

respective lapping wheels

26 and 28 move toward an operative position in engagement with the work piece I3. Movement of the head 38 toward an operative position closes the limit switch |51 which operates through the |5|` which starts the cycle of operation starter switch` |58 to start the motors Il and 88 to start a rotary and/or gyrating movement of the work piece I3 and at the same time to start the rapid planetary, slow rotating, and the simultaneous oscillating movements of the.microlap ping

wheels

26 and 28 to micro-lap the surface of the work piece I3 for a predetermined time interval after which the electrical `time delay relay |55 shifts the control valve |80 to move the lapping

wheels

26 and 28 to an inoperative position and during this movement to stop the motors I4 and 48, respectively. If, during the lapping operation, it is desirable for any reason to stop the cycle, the lever |53 may -be moved to.

ward the left (Fig. 2) or in a clockwise direction (Fig. 10) to actuate the emergency stop butt0n |52 which breaks the circuit, thus rendering the time delay relay inelectlve to immediately return the

wheels

26 and 28 to an inoperative position.

It will thus be seen that there has been provided by this invention apparatus in which theA various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be. made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawingsis to be interpreted as r illustrative and not in a limiting sense.

1. In a micro-lapping machine having a base, a rotatable work supporting platen, means to ro- .tate said platen,` a movable head, power operatedmeans to cause a relative approaching and receding movement between said head and platen, 'and a pair of spaced lapping heads pivotally mounted on Isaid vertically movable headmeach Aincluding a-rotatable, planetarily movable and tate said'platen, a vertically movable head, means to cause a relative approaching and receding movement between said head and platen, and a.

pair of spaced lapping heads-pivotally mounted tary and gyrating movements porting platen.

on said vertically movable head each including a rotatable, planetarily movable lapping element, a motor on said vertically movable head to rotate and revolve said lapping elements, and an oscillating mechanism driven by said motor simultaneously to oscillate said lapping heads in arcuate vpaths and in opposite directions during the rotary and planetary movement ofv said lap elements and work platen` 3. In a micro-lapping machine having a base, a rotatable work supporting platen, means torotate said platen, a vertically movable head, a

to move said element in a planetary path and slowly to rotate said lapping element, and means simultaneously to oscillate said heads in opposite directions.

4. In a micro-lapping machine having a base,

'a rotatable work supporting platen, a work rotating and gyrating mechanism associated therewith to give a plurality of positive deilnite rotary and gyrating movements to a work piece supported on said platen during rotation of the platen.v a vertically movable head, a power operated-mechanism to raise and lower. said head, and a pair of spaced lapping heads pivotally secured on said'vertically movable head each including a rotary planetarily movable and oscil-y latable lapping element, means rapidly to move said lapping elements in a planetary path, means slowly -to rotate said lapping elements on each of said heads,."and means simultaneously to oscillate said heads in arcuate paths during the roof the work sup- 5. In a micro-lapping machine having a base, a rotatable work supporting platen, a work rotating mechanism associated therewith to impart a rotary motion to a work piece supported on said platen, means including a motor within said base to drive said mechanism, a vertically' movable head, means including a piston and cylinder to move said head to cause a relative approaching and receding movement between the vertically movable headv and platena lapping head pivotally mounted on said vertically movable head including a .rotatable planetarily movable and oscillatable lapping element, means including an electric motor on said vertically movable head rapidly to move said lapping element in a planetary path, means slowly to rotate said lappin element, and an oscillating mechanism driven y the motor on said head simultaneously to'oscillate said head in'an arcuate path during' the rotary and planetary movement of said lapping element. 6. In a micro-lapping machine having a base. a vrotatable work supporting platen, means to Arotate said platen, a vertically movable head on said base, a lapping element pivotally supported.` 'l 'on said head, means including a piston and cylinder mechanism to move said head vertically to cause an approaching or receding movement between said head and platen, an electric motor on said head, belt connections between said motor and said lapping :element planetarily to move said element at a comparatively fast speed, driving meanslto rotate said lapping element at a relatively slow speed, a speed reduction unit on said head, driving connections between said motor and speed reduction unit, and means including an adjustable crank mechanism actuated f by said speed reduction unit which is arranged to transmit an oscillatory movement in an arcuate path-to said lappingelement during its rotary and planetary movement.

7. In a micro-lapping .machine having a base,

' a rotatable work supporting platen,.a work driving mechanism associated therewith which is arranged to give the work piece a plurality of positive and denite rotating and gyrating movements during each rotation of the work supporting platen, a vertically movable spindle. a hydraulic piston and cylinder to raise and lower said spindle, and a lapping head pivotally mounted on said spindle including an electric motor, a lapping element having a at operative lapping face, operative connections between said motor and said lapping element rapidly to move.said element in a planetary. path,l driving means slowly to rotate said lapping element, and driving yconnections between said motor and said lapping element to oscillate said element in an n site directions.

` arcuate4 path during the rotaryand gyrating .movements of! the work supporting and driving mechanism. Y ,y

8. In amicro-lappingA machine having a base,

a rotatable work supporting platen, a workdriving mechanism associated therewith which is arranged' to give the work piece a plurality ofpositive and Adeiinite rotating and gyrating movevments during each rotation of the work supporting platen, 'a vertically movable spindle, a hydraulicpiston and cylinder to raise and lower said spindle, a pair oi' spaced lapping elements `pivotally mounted on said spindle arranged to ,engage a: work piece at diametrically opposite 1/ positions, a driving motor on said spindle. driving connections between said motor and each of Vsaid lapping elements rapidly to move said elements in a planetary path, driving mechanisms slowly to rotate each oi.' said lapping elements,

and driving connections between saidmotor and lapping elements simultaneously to escalate said paths and in appr lapping elements in arcuate valve operatively connected to admit iluld to said spindle cylinder, electrically operated means to shift said valve to. initiate a lapping operation. a time delay relay operatively connected to terminate the lapping operation after a predetermined time interval, and means including a switch actuated by the relative approaching movement ot said head to start the work drive motor and the lap driving motor as the lapping element approaches the work piece.

10. In a micro-lapping machine having a base. a-rotatable work supporting platen, a work rotating mechanism associated therewith to im- 9. In amicro-lapping machine having a base,

a rotatablework supporting platen,a work ro tating mechanism associated therewith to im part a rotary motion to a work piece supported on said platen, lmeans including-an electric motor operatively connected to drive said mechanism, a vertically movable spindle, means including a hydraulic piston and cylinder to raise and lowerl .said spindle, a -lapping head on said spindle including an electric motor, a lapping'element on.

said head, driving connections between said motor and said lapping element to rotate and planetarilymove said lappingelement, a control drive motor and the part a rotary motion to a work piece supported on said platen, means including an electric motor operatively connected to drive said mechanism, a vertically movable spindle, means including a hydraulic piston and cylinder to raise and lower` -said spindle, a lapping head on said spindle including anelectric motor, a lapping element on said head, driving connections between said motor and said lapping element to rotate and planetarily move said lapping element, a control valve operativelyonnected to admit fluid to said spindle cylinder, electrically operatedv