Abstract

A grinding machine wherein a column supports a vertically movable holder for the spindle of a grinding wheel and the dressing apparatus is mounted on the holder. The dressing apparatus has a carriage disposed at a level above the grinding wheel and movable up and down radially of the grinding wheel. The carriage has a forward extension for a follower which supports a pivotable carrier for two parallel or nearly parallel spindles each of which carries one or more dressing tools. The carrier is pivotable relative to the follower between a first position in which the first dressing tool is ready to treat the working surface of the grinding wheel and a second position in which the second dressing tool is ready to treat the working surface. Separate motors are provided to move the follower along the carriage, to move the carriage along the holder, to drive the spindles for the dressing tools, as well as to pivot the carrier relative to the follower. The dressing tools have different profiles and the axial distance between such dressing tools can be a small fraction of the axial length of the grinding wheel. The axis of at least one dressing tool is inclined with reference to the axis of the grinding wheel.