Method and apparatus for producing balls

Abstract

Cylindrical or cubical blanks for producing balls, in particular small balls for ball bearings and placed in a vertical tube positioned eccentrically above a grinding disc having a horizontal plane abrasive upper surface which forms the bottom of the tube. The blanks partially fill the tube to a depth many times the cross section dimension of the blanks. For example many thousand of the blanks may be put in the tube at one time. The disc is then rotated to grind and tumble the blanks in the tube and to produce circulation of the blanks in the tube continually to bring different blanks into contact with the abrasive upper surface of the disc. During the grinding operation, a nozzle directs grinding fluid into the tube so as to promote circulation of the blanks in the tube and to inhibit the sticking of blanks to the side walls of the tube. In this manner all of the blanks in the tube are ground to approximately spherical shape. Means is preferably provided for moving the disc and tube toward one another to compensate for wear of the disc and to maintain the sphere relationship between the lower end of the tube and the disc face. If the abrasive of the disc has a hardness lower than the hardness of diamond, means is preferably provided for dressing the upper surface of the disc in order to keep it plane and free of grooves.

Dependencies are inferred from the claim text.