A lapping machine includes a circular drive plate mounted on the end of a driven shaft and a circular lapping plate mounted on the drive plate. A pair of leveling levers are mounted between the drive plate and the lapping plate with each lever being in a groove in the drive plate. Each lever has a pivot point adjacent one end which is pivotedly seated on the drive plate and projects from the groove in the drive plate so that the lapping plate engages the lever. An adjustment screw is at the other end of each lever for adjustably pivoting the lever and thereby tilts the lapping plate with respect to the drive plate. Either the lapping plate or the drive plate has holes therethrough to permit access to the adjustment screws. A drive pin projects from the drive plate and fits in a groove in the bottom of the lapping plate to drive the lapping plate with the drive plate.

BACKGROUND OF THE INVENTION 
The present invention relates to a lapping machine, particularly for 
lapping diamonds, which is easily levelable to permit high speed 
operation. 
In U.S. Pat. No. 4,162,510, issued to Eugene O. Keizer, on July 24, 1979 
entitled "Keel-Tipped Stylus For Video Disc Systems," there is shown and 
described a stylus for use with a high density information record playback 
system, such as a video disc. The stylus is a body of a dielectric 
material, preferably diamond, which is shaped to provide it with a keel 
tip suitable for riding in the groove in the recorded disc. To make this 
stylus it is necessary to perform several lapping operations. Some of such 
lapping operations are carried out on a lapping disc having a flat lapping 
surface. To lap such dielectric material as diamond, which is very hard, 
within a reasonable time, it is desirable to rotate the lapping disc at 
very high speeds, such as at speeds of at least 7000 rpm. When rotating at 
such high speeds, it is essential that the lapping disc be level to 
prevent wobble which could damage the lapping machine and/or prevent 
proper lapping of the diamond. Therefore, it is desirable to have a 
lapping machine in which leveling of the lapping disc can be easily 
achieved. 
SUMMARY OF THE INVENTION 
The present invention relates to a lapping machine which includes a drive 
plate, means for rotating the drive plate about its center, a lapping 
plate mounted on the drive plate, means for causing the lapping plate to 
rotate with the drive plate and means for leveling the lapping plate. The 
means for leveling the lapping plate includes a lever mounted between the 
drive plate and lapping plate. The lever engages the lapping plate and is 
pivoted on the drive plate so that pivotation of the lever tilts the 
lapping plate with respect to the drive plate. Means is provided for 
adjustably pivoting the lever.

DETAILED DESCRIPTION 
Referring to FIGS. 1 and 4, a lapping machine which incorporates the 
present invention is generally designated as 10. The lapping machine 10 
includes a base housing 12 which encloses a suitable high speed motor, not 
shown. Although any type of high speed motor can be used, an electric 
motor is preferred. Extending vertically from the drive motor is a drive 
shaft 14 (see FIG. 1) having a circular drive plate 16 on the end thereof. 
The circumferential edge 18 of the drive plate 16 is tapered radially 
inwardly from the top surface 20 of the drive plate. A cylindrical hub 22 
projects vertically upwardly from the center of the top surface 20 of the 
drive plate 16. The hub 22 has a threaded hole 24 in its top end surface. 
The drive plate 16 has a pair of elongated grooves 26 in its top surface 
20. The grooves 26 are at an angle with respect to each other so as to 
form a V, with the apex of the V being on a diameter of the drive plate 16 
adjacent to but spaced slightly from the hub 22. The angles between the 
diameter along which the apex of the V is located and each of the grooves 
26 are equal. A threaded hole 28 extends through the drive plate 16 at a 
position along the diameter of the drive plate at which the apex of the V 
is located and between the apex of the V and the edge 18 of the drive 
plate 16. As shown in FIG. 3, the hole 28 extends at a slight angle 
radially inwardly from the bottom surface of the drive plate 16. A drive 
pin 30 is threaded in the hole 28 and has a pointed end 32 projecting 
slightly beyond the top surface 20 of the drive plate. 
In each of the grooves 26 in the drive plate 16 is a separate leveling 
lever 34. Each of the levers 34 is a body having a length and width 
corresponding to the length and width of a groove 26. The lever 34 has a 
thick end 36 which is of a thickness, i.e., dimension between the top and 
bottom surfaces of the lever 34, greater than the depth of the groove 26. 
The top and bottom surfaces of the lever 34 taper together from the thick 
end 36 to a thin end 38 which is of a thickness less than the depth of the 
groove 26. The lever 34 has a first pivot point 40 on its bottom surface 
at the thick end 36 and a second pivot point 41 on its top surface 
adjacent to but spaced from the end of the lever 34. A threaded hole 42 
extends through the lever 34 between its top and bottom surfaces at the 
thin end 38. An adjustment screw 44 is threaded through the hole 42 and 
engages the bottom of the groove 26. Rotation of the adjustment screw 44 
causes the thin end 38 of the lever 34 to move up or down in the groove 26 
thereby pivoting the lever 34 about the pivot point 40. The lever 34 has a 
threaded hole 39 extending diagonally therethrough from the top surface to 
the opposite side. A set screw 43 is threaded in the hole 39 and is 
adjustable to engage a side of the groove 26. 
A circular lapping plate 46 is mounted on the drive plate 16. As shown in 
FIGS. 1 and 4, the lapping plate 46 has a central hole 48 therethrough 
which receives the hub 22 of the drive plate 16. As shown in FIG. 1, the 
hole 48 has a rib 49 there around between the ends of the hole. The hole 
48 tapers radially inwardly from its bottom end to the rib 49 and has a 
cylindrical portion larger in diameter than the rib from the top end 
thereof to the rib. The rib 49 is of a diameter equal to the hub 22 so as 
to properly center the lapping plate 26 on the hub 22. The enlarged 
portion of the hole 48 on each side of the rib 49 allows for slight 
tilting of the lapping plate 26 to permit it to be leveled as will be 
explained. If desired, the hole 48 may be cylindrical on both sides of the 
rib 49 as shown in FIG. 5A or may be tapered on both sides of the rib 49 
as shown in FIG. 5B to permit the tilting thereof for leveling purposes. 
A flat washer 50 is on the top surface of the lapping plate 46 over the 
hole 48, and a cup-shaped spring washer 51 is on the flat washer 50. A 
headed screw 52 extends through the washers 50 and 51 and is threaded into 
the hole 24 in the hub 22 to secure the lapping plate 46 onto the drive 
plate 16. 
The lapping disc 46 has a V-shaped groove 54 in its bottom surface 
extending along a radius of the lapping disc. The groove 54 is positioned 
to receive the pointed end 32 of the drive pin 30 so as to cause rotation 
of the lapping plate 46 with the drive plate 16. Also, rotation of the 
drive pin 30 will cause tilting of the lapping plate 46 with regard to the 
drive plate 16. The lapping plate 46 has a pair of holes 56 therethrough 
between the radial inner end of the groove 54 and the center hole 48. The 
holes 46 are positioned so that each receives a separate one of the 
adjustment screws 44. A peripheral portion 58 of the bottom surface of the 
lapping plate 46 is tapered upwardly toward the top surface of the lapping 
plate. Surrounding the lapping plate 46 is a stationary work table 55, the 
bottom surface of which has a portion 57 which is tapered toward the top 
surface at its edge adjacent the lapping plate 46. 
When the lapping plate 46 is mounted on and secured to the drive plate 16, 
the lapping plate 46 can be leveled by first rotating the drive pin 30. As 
previously stated, this will tilt the lapping plate 46 with regard to the 
drive plate 16 to achieve a rough adjustment of the leveling of the 
lapping plate 46. Each of the adjustment screws 44 is then rotated to 
pivot the lever 34 about the pivot point 40. Since the thick end 36 of the 
lever 34 is thicker than the depth of the groove 26, the lapping plate 46 
is seated on the top surfaces of the levers 34. Thus, pivoting the lever 
34 will cause the portion of the lapping plate 46 over the lever to move 
toward or away from the drive plate 16 and thereby tilt the lapping plate 
46 with regard to the drive plate 16. Thus, rotation of the adjustment 
screws 44 will achieve a fine adjustment of the leveling of the lapping 
plate 46. Determination of when and to what degree the lapping plate 46 is 
level can be made with a suitable leveling instrument. 
Thus, the lapping plate 46 can be easily leveled after it is mounted on the 
drive plate 16. In addition, all of the leveling mechanism is contained 
between the drive plate 16 and the lapping plate 46 so that when the 
lapping plate is rotated at high speeds the leveling mechanism cannot be 
thrown loose by the high centrifugal forces applied thereto. Thus, the 
lapping machine of the present invention is safer to use. In addition, the 
lapping plate 46 can be easily removed for refinishing the lapping surface 
and replaced with a minimum of down time. When the lapping plate 46 is 
removed for refinishing, the leveling lever 34 can be locked in the 
grooves 26 by threading each of the set screws 43 until it engages a side 
of its respective groove and the lever 34 is pressed tightly against the 
other side of the groove. The drive plate 16 can then be rotatably 
balanced with the levers therein without loosing the levers. The tapered 
surfaces 18, 58 and 57 of the drive plate 16, lapping plate 46 and table 
55 provide for smooth air flow around these surfaces when the plates are 
rotating at high speeds. This provides for aerodynamic smoothing of the 
rotating plates to allow reduced air drag. 
Referring to FIGS. 6 and 7 there is shown a modification of the lapping 
machine, generally designated as 100, in which the leveling adjustment is 
made from beneath the drive plate 116 rather than through the lapping 
plate. The drive plate 116 is similar to the drive plate 16 shown in FIGS. 
3 and 4 except that the elongated grooves 126 do not extend to a 
substantial common point adjacent the drive pin 130 but extend to points 
adjacent the other edge of the drive plate. The drive plate 116 has a 
separate hole 117 extending therethrough from its bottom surface to the 
bottom of groove 126 at the end of the groove 126 adjacent the drive pin 
130. 
In each of the grooves 126 is a separate leveling lever 134. The leveling 
levers 134 are of the same construction as the leveling levers 34. 
However, the leveling levers 134 are turned over in the grooves 126 so 
that the first pivot point 140 at the thick end 136 engages the bottom of 
the lapping plate 146 and the second pivot point 141, adjacent to but 
spaced from the first pivot point 140, is seated on the bottom of the 
groove 126. A headed adjustment screw 144 extends through the hole 117 in 
the drive plate 116 and is threaded in a hole 142 in the thin end 138 of 
the leveling lever 134. The lapping plate 146 is of the same construction 
as the lapping plate 46, except that it does not require the holes for the 
leveling screws, and is mounted on the drive plate 116 in the same manner 
that the lapping plate 46 is mounted on the drive plate 16. 
The weight of the lapping plate 146 on the leveling levers 134 causes them 
to pivot about the second pivot point 141 so that the thin end 138 is 
lifted off the bottom of the grooves 126. Rotation of the adjustment 
screws 144 will pivot the leveling levers 134 so as to cause tilting of 
the lapping plate 146 to permit leveling of the lapping plate as 
previously described. Thus the lapping machine 100 permits leveling of the 
lapping plate 146 from beneath the drive plate 116.