US3004371A - Bench-type lapping machine - Google Patents

Description

Oct. 17, 1961 F. E. LAYTON ETAL BENCH-TYPE LAPPING MACHINE 3 Sheets-Sheet 1 Filed April 8, 1958 TT'Y INVENTORB FORREST E. LAYTON HARRY I. SOLE Oct. 17, 1961 F. E. LAYTON ET AL BENCH-TYPE LAPPING MACHINE Filed April 8, 1958 3 Sheets-Sheet FORREST E. LAYTO'N HARRYLSOLE ZM 27 f FIG.2

Oct. 17, 1961 F. E. LAYTON ETAL BENCHTYPE LAPPING MACHINE 5 Sheets-Sheet 3 Filed April 8, 1958 1 HI ll l INVENTORS: FOR REST E. LAYTON HARRY I. SOLE BY TT'Y United States This invention relates to a bench-type fiat lapping machine.

The principal object of this invention is the provision of a small, inexpensive lapping machine for use primarily as a tool in a machine shop or the like or for lapping small runsof articles.

As a more specific object, this invention has within its purview the provision of a bench-type lapping machine which incorporates an inexpensive means for removing spent grit and lapping debris from the area immediately adjacent the effective lapping surface.

A specific object of this invention is the provision of a simple, adjustable holding means for articles on a lap, said holding means being sufliciently adaptable to hold in one arrangement a pair of cylindrical articles on the lap with the end faces of the articles in contact with the lap surface, and in another arrangement, to hold between them a single larger cylindrical object with its end face similarly disposed.

A further object of this invention is the provision of a holding means .for an article on a fiat lap, said means being capable of swinging adjustment in an arc over the lap and. also of adjustment in a vertical direction to accommodate articles of various heights on the lap.

.A feature of this invention is a novel support for the drive means for an annular lap, said support also serving as a support for an annular container for spent grit and lapping debris.

These and other objects and features of this invention will become apparent from the following detailed description when taken together with the accompanying drawings in which,

FIG. 1 is a plan view of a lapping machine incorporating the features of this invention;

FIG. 2 is a side elevational view, partly in section, of the machine of FIG. 1;

FIG. 3 is an end elevational view of the machine of FIG. 1 with a portion of the end of the machine broken away to show the interior thereof;

FIG. 4 is a fragmentary section taken in the direction of the arrows at line 4-4 in FIG. 1 showing a detail of construction of the machine;

FIG. 5 is a plan view, on a reduced scale, of the machine of FIG. 1 showing the article holding means adjusted for holding a large cylindrical object on the lap; and

FIG. 6 is an elevational view of a detail of the machine of FIG. 1.

Referring now to the drawings, and particularly to FIGS. 1 and 2, for a detailed description of the invention, there is shown a fiat, disc-shaped lap 10 having a recess 11 in the central region of its upper surface to provide an annular lap surface 12 thereon. Said surface 12 may have a series of radially disposed slots 13, or a single spiral groove (not shown), milled or otherwise formed in it for the purpose of conducting spent grit and lapping debris from the lap surface. Lap 10 has a substantial thickness to provide rigidity for the purpose of maintaining a given contour on surface 12.

Lap 10 may have fiat undersurface 15 upon which the lap is supported from the flanged end 16 of a drive shaft 17. The of shaft 17 is vertically disposed, and the lower region of the shafthas a relatively deep round recess 18 into which is inserted, with a relatively close fit,

T atent O the output shaft w of a reduction gear drive 20, the housing 21 of which may be formed as an integral part of the housing 22 of an electric drive motor 23. Said motor and reduction gearing may be of any well known and readily available type and hence the details of construction thereof will not be described herein.

Lap 10 is secured to the flanged end 16 of drive shaft 17 by a machine screw 24 preferably passing through a counter-sunk opening disposed in the center of lap 10 and threaded into a corresponding opening 25 concentric with the axis of the flanged end 16 of shaft 17. Driving torque is transmitted from shaft 17 to lap 10 by a drive pin 26 press-fitted into an appropriate opening in the flanged end 16 of the shaft and extending upwardly beyond surface 15 into a recess 27 formed in the underside of lap 10. The drive from shaft 19 to shaft 17 is effected by a key 28 interlocking the two shafts and held in place by a setscrew 29.

Some of the spent grit and lapping debris falls into recess 11 and is conducted therefrom through radially and downwardly disposed passages 31 and 31 to the exterior cylindrical surface 32 of lap it while the rest moves radially outwardly on surface 12 or along grooves 13 directly to said cylindrical surface 32. The grit and debris falling along cylindrical surface 34 is then collected in an annular container 33 having a cylindrical outer wall 34, an inner cylindrical wall and a connecting frustoconical wall 36. it is understood that walls 34 and 35 need not be cylindrical but for ease of manufacture are preferably made so. Thus, for example, container 33 may be a sheet metal stamping and hence may be more readily made if walls 34 and 35 are substantially cylindrical.

7 Outer cylindrical wall 34 has an inner diameter which is slightly greater than the diameter of the exterior cylindrical surface 32 of lap 10 to allow the grit and debris to pass therebetween, and extends upward around the lower regions of lap 10, particularly above the exit ends 38, 39 of the passages 30 and 31, respectively, so that the grit and debris issuing from said exit ends will fall into container 33. The upper edge 40 of outer wall 34 is rolled over to give stiffness to said edge and also to provide a smoothly rounded entering and locating surface for lap 10 when said lap is assembled with respect to shaft 17.

To provide greater assurance that the contents of container 33 will not flow over inner wall 35 into housing 21 of the gear reducer 20, wall .35 is likewise made to extend upward beyond surface 15 into an annular groove 41 formed in'said surface 15.

Container 33 is drained through a pipe 42, shown more clearly in FIGS. 1 and 3, threaded into a fitting 43 welded to the lower region of outer cylindrical wall 34 over an opening 44 therein. Said pipe 42 is supported in such manner that the inner wall thereof slopes downward and promotes natural drainage of the contents of the container through the pipe to any suitable collecting means (not shown) provided by the operator. Movement of the contents of the container past opening '44 to promote flow therethrough is established by a paddle 45 (FIG. 2) preferably made of sheet metal and having a contour closely following the cross-sectional contour of container 33. Said paddle 45 has a horizontally disposed flange 46 (FIG. 3) which abuts on the underside of lap 10 and provides a means for applying fasteners 7 therethrough to the said underside of the lap. It may be appreciated that as the lap is rotated, paddle 45 will be rotated with it and will sweep around container 34, thus moving any lapping compound or debris collected therein past opening 44 while at the same time preventing a settling out of the compound.

Container 33, as well as housing 21 of the reduction gearing 20, are supported by a plate 48 which, in turn,

is supported from the top plate 49 of the frame 50 of the lapping machine. Said plate 48 may be cut to have an octagonal outer edge 51 (FIG. 1) and a circular inner edge 52 (FIGS. 2 and 3), but it is understood that the contour of the outer and inner edges of plate 48 are not material to the operation of this invention and may be varied to suit special circumstances. The support for plate 48 is comprised of a plurality of vertically disposed weldments 53 (FIG. 4) preferably of rectangular outline and welded at the top and bottom to the upper and lower plates 49 and 48, respectively. Said weldments 53 are disposed near the octagonal edge 51 of plate 48 and, of course, outside the container 33.

It may be observed from FIGS. 2 and 3 that upper Y plate 49 has a circular opening 54 therein through which extends, in relatively close proximity thereto, the outer cylindrical wall 34 of container 33. It may be noted further that the rolled edge 40 of the Wall 34 is disposed above the upper surface of plate 49 and overlaps and conceals the edge of the opening 54.

Housing 21 is provided with the usual attaching flange 55 which abuts on the underside of plate 48 and is secured thereto by a series of bolts 56. Container 33 is secured to the upper side of plate 48 through a plurality of Z-shaped stamped tabs 57, the upper leg 58 of which may be spot welded to the inner peripheral regions of the frusto-conical bottom wall 36 of the container and the lower legs 59 of which are fastened to the upper surface of plate 48 by screws 60. It is contemplated that container 33 will be supported at its inner edges by the tabs 57 and that its outer edge will rest upon the upper surface of plate 48.

Frame 50 is comprised, in addition to top. plate 49, of

a side skirt 61 to the upper edge of which plate 49 may be Welded or otherwise secured, said skirt being shaped to form legs 62 in the corners thereof, the bottom of said legs being covered by a plate 63 suitably welded to the inner surfaces of the skirt corner and provided with a threaded opening 64 for the reception of a fastener 65 by which a rubber foot 66 may be secured to said plate 63. Appropriate openings 67, 68 and 69 are provided in the end and back regions of the skirt 61 for ventilation purposes and for access to the drain pipe 42 as well as to a plug 70 by which lubricant may be introduced into housing 21 of the gear reducer 20.

Considering now the operative surface 12 of the lap 10, it is contemplated that articles may be lapped on said surface 12 either by being held thereon by an operator while the lap is rotating, or by being placed in suitable holders provided for that purpose on the machine so that the operator may be occupied elsewhere while the articles of a material adapted to Wear the surface 12 and have a size large enough to cause the outer peripheral regions 101 (FIG. 2) to overhang the exterior cylindrical surface 32 of lap 10, and also to overlap, or overhang, the edges of the recess '11 while the inner surface 72A of the ring 71 is of either the same, or slightly smaller, size as the radial dimension of annular lap surface 12. Said rings have bottom surfaces of a contour complementary to the contour of the lap surface 12 which sweep over lap surface 12 and continually dress the said lap surface, all as described in the aforementioned patent to Bullard.

The means for holding ring 71 on lap surface '12 against revolution therewithis comprised of a triangular plate 73 having a curved arm 74 extending from one of as to cause the outer surface 76 of the roller to extend beyond the opposed edges of 77, 78 of the arm. In an- 4 other apex 79 of the triangular plate 73 is disposed a second roller 80 having a surface 81 which extends outwardly beyond the adjacent edges of plate 73. It is contemplated that plate 73 will be so disposed relative to surface 12 that a ring 71 may be supported rotatably between surfaces 76 and 80 of rollers 75 and 81, it being understood that the distance between said surfaces is less than the diameter of the outer surface of ring 71 and that the axes of rollers 75 and 81 are parallel to the axis of ring 71.

The supporting means for plate 73 includes a threaded post 82, the lower end of which passes through an opening 84 in top plate 49 and into the threaded opening 85 of a boss 83 formed by welding or otherwise rigidly securing a cylinder of metal to the underside of top plate 49. Post 82 is prevented from turning relative to threaded bushing 83, once its desired vertical position is established, by a lock nut 86 threaded over post 82 and clamped against the upper surface of top .plate 49. For convenience in turning post 82, the upper end 87 of the post may be squared off to accommodate a wrench or the 9 like.

. Extending upwardly from the upper surface 88 of the squared end 87 of post 82 is a threaded extension 89 of surface 88. Said plate 73 is clamped to surface 88 by a hand nut 91 threaded over extension 89 and hearing I 7 against plate 73 to clamp the plate against said surface 88.

An alternate and convenient means is provided for turning post 82 in bushing 83 without the aid of a wrench or special tool said means comprising (FIG. 6) a raised, parallel sided extension 101 on upper surface 88 fitting snugly into slot 90 in plate 73. Thus plate 73 may serve as the wrench for turning post 82.

The rotatable support for ring 72 is identical in every 'respect to that for ring 71 and hence will not be described in detail herein, it being suflicient to state that it is comprised of a post 92 to which may be clamped a plate 93 having an arm 94 on the end of which is a roller 95, a second roller 96 on plate 93 being spaced from roller 95 a lesser distance than the outside diameter of ring 72 so that said ring is supported against movement with the "lap by said rollers 95 and 96. A hand nut 97 locks plate 93 on its post 92. It is understood that posts 82 and 92 are interchangeable as well as plates 73 and 93 and hand nuts 91 and 97.

It may be apparent that posts 82 and 92 may beadjusted vertically to accommodate rings of different height on lap surface 12 and the plates 73 and 93 may be adjusted both angularly and translatively with respect to the posts to give great freedom of choice as to the location of an article on lap surface .12; Thus, work may be placed in rings 71 and 72 and the location of said rings with reference to lap surface 12 so selected as to cause said surface to remain true to its original contour for a long period of time despite the fact that such'surface may be continually abraded by the articles being lapped. Alternatively, in place of one or both rings 71, 72, a cylindrical object may be placed on lap surface 12 and made to bear against rollers 75 and 8%, or and 96 directly, while the article 'is being lapped.

Occasionally, it may be desirable or necessary to lap a cylindrical article which is considerably larger in diameter than rings 71 and 72. Such over-sized articles may nevertheless be successfully lapped on the foregoing machine by arranging the plates 73 and 93 in the manner illustrated in FIG. 5. Thus, assuming that the over-sized article 98 is of approximately the size illustrated in FIG. 5 such that it would extend across central recess 11 if the outer edge thereof did not greatly overlap the outer edge of the lap. For an object of such size a spacing between the rollers 75 and 80 might not be sufficient to retain the article on the lap under certain conditions of operation. It is therefore desirable to make use of both plates 73 and 93 and use roller 75 of plate 73 and roller 95 of plate 93 to provide a roller support for the article 98 wherein the rollers are spaced apart a sufficient distance to ensure the retention of the article on the lap 12 at all times. Roller 95 is made available for this purpose by rotating plate 93 to such an extent that what amounts to the back of plate 93 is presented to the article 98 and roller 96 is unused. Similarly, plate 73 is rotated to such an extent that roller 75 only contacts article 98, roller 80 being disposed in proximity to, but not necessarily in contact with the article 98.

Obviously, when an article such as the one shown in FIG. is being lapped, there is no room for a conditioning ring such as 71 or 72 on the lap at the same time, and hence the conditioning of the lap under these circumstances must be performed when the article is removed.

In addition to the arrangement of plates 73 and 93 as shown in FIG. 5, it is obvious that said plates may be reversed in the sense that they are inverted, the inverted position being available for relatively high articles to make certain that ample clearance would still remain for the arms of the plates above the lap surface 12.

The machine may be provided with an olf-0n switch 99 and a timer switch 100, both of which may be disposed in a conveniently accessible location of the machine, preferably on the skirt 61 adjacent the motor 23 which it is desired to control. Both switch 99 and timer switch 100 may be of known and readily available construction and hence the details thereof will not be described herein. Suflice it to say, that with switch 99 in its on position, timer switch 100 may be set for any desired duration of operation of motor 23 within the limits of the timer switch, and upon the lapse of the time set, the motor will cease operating so that it is unnecessary for an operator to stand by the machine once he has placed an article to be lapped on plate 12 and set the machine in operation.

The general operation of the above-described lapping locations shown in FIG. 1 being illustrative of the extreme radially inner and outer positions likely to be encountered. It may be apparent that the foregoing machine, when designed for use with a lap plate 10 of small diameter, e.g., ten inches, may be inexpensively constructed and yet will accommodate a large range of sizes of articles as well as provide automatic conditioning of the lap so that the machine may be used continuously for small production rims.

It is understood that the foregoing description is merely illustrative of a preferred embodiment of the invention and that the scope of the invention therefore is not to be limited thereto, but is to be determined by the appended claims.

We claim:

1. A lapping machine comprising a rotatable lap, a pivoted support for articles to be lapped on said lap, said support comprising a fixed frame having a threaded opening, a post having a threaded region engaging said threaded opening and extending above the frame in proximity to the lap, said post having a flat-sided region adjacent the threaded region thereon, a plate extending in part over the lap end having a slot therein, said flat-sided end region extending into and engaging the side of the slot and locked against rotation relatively thereto by such engagement with the side of the slot but free to slide transversely of the post to vary the amount by which the plate extends over the lap, means on the plate for engaging an article to be lapped on the lap, means for locking the plate to the post against such transverse sliding thereon, and means for locking the post to the frame against relative rotation therewith, said plate functioning as a wrench to turn the post when said post is not locked to the frame.

2. A lapping machine as described in claim 1, said post having a shoulder between the flat-sided region and the threaded region against which the plate bears, and said means for locking the plate to the post comprising a hand nut threaded on the end of the post adjacent the plate and adapted to clamp the plate against the shoulder.

References Cited in the file of this patent UNITED STATES PATENTS 1,569,194 Long Jan. 12, 1926 2,274,332 Jarrett Feb. 24, 1942 2,627,144 Roshong Feb. 3, 1953 2,653,422 Roshong Sept. 29, 1953 2,782,571 Hanson Feb. 26, 1957

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