Grinding machine with rest apparatus

Claim 1

A grinding machine for grinding a workpiece comprising: a bed; means mounted on said bed for rotatably supporting said workpiece; first drive means for rotating said workpiece; a wheel head slidably mounted on said bed for rotatably supporting a grinding wheel thereon; second drive means for rotating said grinding wheel; a first servomotor for moving said wheel head so as to move said grinding wheel toward and away from said workpiece; a rest apparatus comprising a pair of rest shoes movable toward said workpiece to support the same; a second servomotor for moving said rest shoes; means for measuring a diametral dimension of a workpiece during a grinding operation; a main control circuit for sequentially enabling an automatic grinding operation; first presetting means for digitally presetting variety of feed amounts; second presetting means for digitally presetting a variety of feed speeds; a digital feed device responsive to said measuring means and said main control circuit for selectively selecting one of the feed speeds preset in said first presetting means and one of the feed amounts preset in said second presetting means to cause one of said first and second servomotors to move one of said wheel head and said pair of rest shoes at a selected feed speed through a selected feed amount; means for calculating a taper amount of a workpiece ground under the support of said rest shoes being positioned at their advanced positions at the time when said measuring means generates a signal for finishing a grinding operation on said workpiece; and means responsive to said calculating means for compensating for advanced positions of said rest shoes for a next grinding operation.