US2391388A - Grinding and lapping machine - Google Patents

Description

E. J. BULLARD GRINDING AND LAPPING MACHINE s Sheets-Shet 1 Filed July 5, 1943 Zmventor; 154 04 J 61 44/1190,

'Dec. 25; T91 5. E. J. BULLARD GRINDING AND LAPPING MACHINE Filed July 5, 1943 3 Sheets-Sheet 2 3nvcutor g 'fmz J BU /m0,

' attorney.

Dec. 25, 1945. E. J. BULLARD v GRINDING AND LAPPING MACHINE Filed July 5, 1943 5 Sheets-Sheet 5 424 BULMRD.

Zsnvcutor attorney- Patented Dec. 25, 1945 S" PATENT 4 OFFICE.

GRINDING AND meme MACHINE f r Y Earl r. Bullard, Altadena, cam. Application July 5, 1943, Serial No. 493,531

' 3 claims. 01. 51-131) This invention contemplates animprovement upon my grinding and lapping machine as disclosed in U. S. Letters Patent No. 2,209,071; issued July 23, 1940.

An object of the present invention i 'to prevent synchronism between movement of a lap and the work.

I have found in actual practice that Where a lap together with a work holder is revolved by a common means, although at differential speeds, a synchronism of movement results which causes the lap to wear unevenly and become wavy in form, thereby requiring replaning of the lap. The present invention overcomes the difiiculty aforesaid, with starting and stopping of the lap independent of any movement of the work.

Another object'is the provision ofa-novel lap which is so constructed and arranged that the working surface thereof may be maintained in V a selected plane. 7

With respect to the foregoing object it may be pointed out that laps of the character of the present invention are quite large, being six feet or and its associated members are carried upon a tubular pedestal 4 standing between the said lap and its associated mechanism and base, I, said pedestal being braced by a plurality of spaced legs 5 positioned'betwe'en the pedestal and the base I. Extending axially of the pedestal 4 is a spindle or'shaft 6. A motor I supported on floor 2 is adapted to drive the spindle or shaft 6 throughthemedium of reduction drives 8 and 9, these reduction drives constitute a'transmission means. In'the present instance, by way of exam-.

ple; the gear reduction between the drive 8 and the motor. is substantially ten to one, and. between the drive 9 and the spindle or shaft 6 a reduction of three to one. It is obvious that various reduced speed means may be r'itilized.

more in diameter and weighing three tons or more. Dressing of such a lap entails time and expense, and likewise requires the cutting away of the working surface'of the lap in order to provide a plane surface. With the present invention I have provided a lap so constructed and its parts so arranged that the working surface of the lap may at all times be'maintained with a given surface, with the result that a minimum amount of stock is taken away. 7 7

Another object of the invention resides in the provision of suitable means which will quickly and efficiently allow for adjustability of a work holder to accommodate various thicknesses of work.

In the drawings: f r

Fig. 1 is a partial fragmentary elevation of the complete grinding and lapping machine;

Fig. 2 is a fragmentary top plan view of the lapping machine; and 7 Fig. 3 is an enlarged fragmentary transverse sectional view on the line 3-'-3 of Fig. 2.

Referring now to the drawings, it may be I stated that fora full and complete explanation of the grinding and lapping machine reference is made'to my U. S. Letters Patent No. 2,209,071.

The-present description will be directed pr'imarily tothe improvements made in certain members of the grinding and lapping machine.

The grinding and lapping machine, briefly, is adapted to be supported by a base I upon a suitable foundation such as a floor 2. The lap 3 The'shaft Bis changed in diameter soas to have enlarged portions with respect to the overall length of said shaft at l0 and ii, there being suitable bearing means indicated generally as 12 between the shaft diameter portion [0 and'the pedestal 4; and adjacent the upper end of said pedestal. The platform or table I3 for the lap 3 is supported by means M which is carried on the portion ll of shaft 6. The means, l4 com prises an annulus [5 provided withspaced-apart end flanges. l6 and H. The flange 16 is provided with an end flange l8, to which are secured ribs IQ (of which there may be a spaced;plurality depending from the under surface of'the platform or table 13), by means of bolts-2(l.

The lap 3 is adapted-to fulcrum on the platform or table l3. The lap in the present instance consistsof a plurality of sectors, as best shown; in

Fig.2. The sectors are arrangedso as to form a complete annulus. Each lap sector is radially coredon its bottom surface, as indicated at 2| to reduce weight, and the base is provided with a ful- .crum 22 extending between the sides of the sector; and which may be intermediately positioned'between the curved ends of said sector. fulcrum does not in the present instance have a knife edgebut has a flat surface 23 in engagement-with the platform. Each sector of the lap is provided, adjacent its inner curvedend 24,w '.th a'bent arm 25, which arm is adapted to cooperate with nut 26 in such a way that movement of the nut will simultaneously tip all of said lap sectors relative to thefulcrum points thereof. Nut 26 is-threaded on a shaft 21; preferably the threads'are 12 or less to the inch so as to permit adjustment of theI laps if r the laps are to be tipped. Nut 26 1 is provided with end fianges 28= and 29, and between, said;

flanges is positioned an end portion of each lap arm 25. The flange 29 is provided with an embossment at 30, the embossment engaging each arm 25, while one or more adjustment screws 3| are in threaded engagement with the top flange 28 for contact with the arms 25, each arm being held between the embossment 30 and one or more of the screws 3|. The shaft 2! has welded thereto a flange 32. Flange 32 in turn is held in operative relationship with the platform I 3 and flange l6 of the means M by bolts 33.

The shaftZl is provided substantially. throughout its length, starting with the term nation of the threaded area for nut 26, with coarse threads 34. The coarse threads may run eight to the inch, more or less. This threaded area carries a nut 35,

provided with an end flange 36. -1he1rut 3ii-is split longitudinally and horizontally toprovide collet 31, which carries bolts 38. Thus having adjusted the nut as to position on shaftfl the bolts 38 may be tightened to clamp the collet 311m the shaft and prevent any rotation of the nut. The n t carries a-washer .39 on its :fiange:36..and a bushin spider, designated generallyv as 4 I isprovided Witha-hl1b42 which rests on: the washer 89: and bears against bushing 4.9. The spider is provided with a-plura'lity-of equidistantly spaced arms radiatinsfromthe hub, these arms beingdesignated generally by :43, see 'Fig. 2. Each spider arm carries a membersll, which isiforklike or bifur= cated in form, in that it constitutes a pair :o-i spaced-apart arms :45 and .46. Member supportsa workhol'ding disetfl. There is a plurality of workholding discs, as shown in Fig; 2, said discs being positioned 1* above: the" lap. Each workho'lding'discill is provided :with a hub formedin two parts 49 and. 50. Parts. 49 and 50 are flanged at andi-SZ, and the flanges are held together in any suitable manner, such as by bolts- 53. Part4!) is provided with two enlarged spaced apart flan os 54 and'155, which brid-ge opposite sides of member 44. The construction is such that a member central of the flanges 54 and 55 is receivedin the way between the members 45 and 45. This construction is detailed in my patent heretofore mentioned. Each'hub 48 is adapted to be rotated when a sprocket 58 associated therewith is driven. There is a sprocket 56 for driving each hub and a continuous chain 51 is passed around said sprockets. A motor58 is secured to a' suitable bracket '59, the bracket in turn being upported between two of the spider arms, as shown at in Fig. 2. The motor shaft carries asprocket 6i and one of the hub members for a workhoiding disc is provided with a sprocket 62, around which sprockets GI and l 62 is passed a continuous chain-63.

Each-workholding disc s Provided with a plurality of transverse openings, within which openings is-placed the work, as is shown, forexample, in Fig; 3 at 64.

The operation, uses and advantages ofthe i-nvention justdescribed are as follows:

It is intended that the lap should bedriven through the transmission means by motor 1, and that the 'workholding disc should be rota-tedby motor-58. This is in orderto prevent synchronism of movement between the workholding discs and the lap, and'for the reasons pointed out in the statement of objects of the invention, The --arrangement is such thata clutch means is provided between eachworkholding-disohub and the driving sprocket,-to the end that the hub may "be removedfrom between the members-45 and to make repairs to the workholding disc, if necessary. For a description of the construction see my Patent No. 2,209,071. However, in the present construction, by forming the hub 48 in two parts, 5 the flanges 5| and 52 may be separated without disturbing other portions of the hub. This twopart hub construction is of value when different thicknesses of workholding discs are to be utilized. To begin with, the lap sectors may be adjusted so that the top surfaces of all-sectors lie; in the same plane by adjusting the nut 26 either upwardly or downwardly relative to the threaded shaft 21. W en the top surface of the lap requires redressing, the lap is adjusted as desired by movement of nut'26- to bring the top surface of the laps into ,acommon. plane, followed by taking a cut across the lap and then repolishing. By way of example, the set screws 4! are loosened, whereupon the nut 26 1s rotated either upwardly or downwardly to tip each lap sector about its fulcrum. After the required tippin the, .lap' sectors 1- are 'all secured yth screw-s3 I.

When it is desired to raise the workholdine disc above the lap, motor 1 will turnthe pindle or shaft '6 .1l; lW e rotate simultaneous thercwith,.'.sbaft .21.:and .itthe spider i he d against movement by the lock bar 65 (see Fig.1) the :31- wil travelo threads a upward direction relative toathe sha t andl tthe sp de to any. desired. hei ht, l mited of .oours by t ength oithethreedodrarea haveassum dwf eurse,--that1 her bolts 3. have een loosened s s to Pormi .375 t radia y travel on. s the hreads 3 this;

bar is. "formed with o.lonsitudmalslowl which allo s this lookbar tote raised relativetoa l n fileeourcd o the namin When the workholding discs .-;are positioned ab ve the lap, w th work such as 54 with n h orkrroceiving openings. hejlanis. rotated and th orkhold ng disosare likewise r ta ed, with the result that the Work has the surface thereof rou d. by the lab.

-I claim:

- 1. In a grind ng and lapping. machine, the-combination-oi: a l p c mpo dof indep ndent s t r rranged inoon u us annularlati n hip and means i f r varyingth an le: of ea h sec or el tive to a. horizontal: pl ne- 1 In a rindin and lappinemachine, the comn i n a c nti u us annul rlap formed in rs, a latform b neath said l nand a fulcrumfor eachsectorin contact W th said platform, and-means for; ti ping ach s ctor. about i s l rum o adj st the plane of said lap- 3. In a grinding and lapping machine, the combination of: a shaft, a motor-for rotating said shaf a plotformsu ported anon. end of said shaft. 11 econdsshait coa ial w the fir t shait and. formedwith two t eadedzones, a nut carried on one of said threaded zones, alap formed, in ec ors-and oborotively connected t said out, rmovmento said not adiusts-theplane oi s id s to s, a workh l or Po tioned. above said ap. a second out upon the second th eaded zon of aid second shaft. and-a solder betw en'said w rkholdor' andsoid. nut. the turn n Qf he se ondnut positioning theeis tof the workholder above saidlap, andmean for-rotatin he Workholder. 7

J -BULLARD.

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