Parts carrier assembly for grinding machine

A parts carrier assembly in combination with a grinding machine,

• the parts carrier assembly including
• an annular parts carrier including an upper surface, a lower surface, an inner edge, an outer edge and a plurality of loading apertures extending through the parts carrier from the upper surface to the lower surface, wherein the inner edge is configured to engage a driving wheel of the grinding machine rotating about a central axis resulting in rotation of the parts carrier about an offset axis, which is offset from the central axis, wherein the loading apertures are configured to receive associated parts to be ground by the grinding machine;
• and
• a bearing insert having an inner bearing surface complementary in shape to the outer edge of the parts carrier, wherein the outer surface of the parts carrier bears against the inner bearing surface of the bearing insert as the parts carrier rotates about the offset axis, wherein the bearing insert is substantially crescent shaped when viewed normal to the central axis,
• the grinding machine including an upper grinding wheel having an upper substantially planar grinding surface, a lower grinding wheel having a lower substantially planar grinding surface, the driving wheel which is axially interposed between the upper grinding wheel and the lower grinding wheel, and an outer fixed ring axially each interposed between the upper grinding wheel and the lower grinding wheel,
• wherein the bearing insert is fixed to the outer fixed ring to inhibit rotation of the bearing insert with respect to the outer fixed ring.

A method for grinding parts comprising:

• loading a plurality of parts that are to be ground into an annular parts carrier that surrounds a central axis;
• rotating a grinding wheel including a substantially planar grinding surface about the central axis, the grinding surface having an outer diameter od1;
• rotating the parts carrier having an outer diameter od2, which is greater than od1/2, about an offset axis, which is offset from the central axis;
• positioning a bearing insert between the parts carrier and an outer ring, wherein an inner diameter of the outer ring is substantially equal to od1, and wherein the bearing insert is substantially crescent shaped when viewed normal to the central axis;
• and
• contacting the grinding surface of the rotating grinding wheel with the parts that have been loaded into the parts carrier.