Truing and dressing apparatus for grinding wheels

An apparatus for truing and dressing a grinding wheel made of cubic boron nitride and rotatably mounted on a grinding machine, comprising in combination:

• roll carriage means slidably mounted on said grinding machine so as to be moved in a first direction heading for said grinding wheel and in a second direction transversely relative to said first direction;
• a truing roll provided at an outer peripheral surface thereof with abrasive grain as hard as diamond and rotatably supported on said roll carriage means with its rotational axis parallel with said second direction;
• a dressing roll made of metal and rotatably supported on said roll carriage means with its rotational axis parallel with said second direction, said truing and dressing rolls being arranged to establish a gap of a predetermined distance between said dressing roll and said grinding wheel when said roll carriage means is fed to such a position in said first direction as to contact said truing roll with the grinding wheel;
• in-feed means for feeding said roll carriage means toward said grinding wheel so as to give an in-feed movement of a predetermined amount to said truing and dressing rolls;
• traverse feed means for moving said roll carriage means in said second direction so as to contact said truing roll with said grinding wheel over the entire width of the same in a truing operation and so as to face said dressing roll with said grinding wheel after said truing operation and prior to a dressing operation;
• and
• means for supplying liberation abrasive grain toward said gap between said dressing roll and said grinding wheel during said dressing operation, the mean size of said liberation abrasive grain being larger than said gap.